Subsurface Facility Worker Dose Assessment Rev 00A, ICN 00

800-00C-SS00-00100-000-00A

 February 2004 


1. PURPOSE 
The purpose of this design calculation is to estimate radiation doses received by personnel 
working in the subsurface facility of the repository performing emplacement, maintenance, and 
retrieval operations under normal conditions. The results of this calculation will be used to 
support the design of the subsurface facilities and provide occupational dose estimates for the 
License Application. 
2. QUALITY ASSURANCE 
This document was prepared in accordance with AP-3.12Q, Design Calculations and Analyses. 
Because the results of this calculation will be used to support the Preclosure Safety Analysis 
relative to radiological safety of the repository, this document is subject to the requirements of 
the Quality Assurance Requirements and Description, DOE/RW-0333P, document (DOE 2003, 
Section 2.2.2). 
3. METHOD 
The methodology used in this calculation consists of three major elements, including a 
subsurface facility worker dose assessment, a comparison with applicable occupational dose 
regulations and criteria, and a discussion of how uncertainties, conservative inputs, and bounding 
assumptions impact the results of this calculation. 
The dose assessment involves calculations of annual individual and collective doses to 
subsurface repository workers. These occupational doses are defined as the Total Effective Dose 
Equivalent (TEDE) received by workers involved in subsurface facility operations. The TEDE 
consists of the deep-dose equivalent from direct exposure to contained sources and airborne 
radionuclides (submersion), summed to the committed effective dose equivalent from inhalation 
of airborne radionuclides. 
During emplacement and retrieval operations, the sealed waste packages are either enclosed by 
the shielded waste package transporter or are transferred to or from the waste package transporter 
downstream (based on the ventilation flow direction in the subsurface facility) from any 
subsurface workers. Therefore, any airborne release of radionuclides from the surface of waste 
packages being emplaced or retrieved would not contribute directly to the inhalation dose to 
subsurface workers performing these operations, and only external doses are considered in this 
calculation. 
The dose assessment is performed by job function or a worker group using the time-motion 
inputs and dose rates calculated at various worker locations. Two major worker groups are 
addressed in this calculation: waste package emplacement and retrieval personnel and 
subsurface maintenance personnel. 
For workers involved in the subsurface emplacement of waste packages, operations begin at the 
time the waste package is loaded onto the transporter at the Dry Transfer Facility (DTF) or 

800-00C-SS00-00100-000-00A 8 of 42 February 2004 
Canister Handling Facility (CHF). During retrieval, operations begin when an empty transporter 
leaves the DTF or CHF to retrieve an emplaced waste package. Each emplacement operation 
ends when the operators return the empty transporter to the surface to pick up a new waste 
package; each retrieval operation ends when the transporter delivers a waste package to the 
receiving surface facility. Initial calculations are made on a per-waste-package basis using an 
Excel spreadsheet. The resulting individual or collective doses are then multiplied by the 
maximum number of waste packages transferred between surface and subsurface facilities per 
year. Individual worker dose assessments take into account the possibility of multiple shifts per 
day so that total time worked per day does not exceed eight hours for any given worker. The 
equation used to calculate the annual individual dose to a waste package emplacement and 
retrieval worker is: 
EDg = Si (EDRi,g × Ti) × WPg (Eq. 1) 
where: 
EDg = External dose to a worker in group g (mrem/yr) 
EDRi,g = External dose rate at location i to a worker in group g (mrem/hr) 
Ti = Duration of the exposure at location i per transfer operation 
(hr/transfer) 
WPg = Annual number of waste package transfers involving a worker in 
group g (transfers/yr) 
To assess the individual dose to maintenance workers, Equation 1 is slightly modified as follows: 
EDg = Si (EDRi,g × Ti) × Mg (Eq. 2) 
where: 
Ti = Duration of the exposure at location i per maintenance operation 
(hr/operation) 
Mg = Annual number of maintenance operations involving a worker in 
group g (operations/yr) 
The collective dose for a group of workers explicitly accounts for multiple shifts (e.g., two waste 
package transfers per day using two work crews, per Assumption 4.2.11) by summing the 
individual doses of all workers in group g as follows: 
CEDg = Sg(Pg × EDg)/1000 (Eq. 3) 
where: 
CEDg = Collective annual dose to worker group g (person-rem/yr) 
Pg = Number of workers in group g (person) 
1000 = Unit conversion factor (mrem/rem) 

800-00C-SS00-00100-000-00A 9 of 42 February 2004 
Equation 3 applies to both emplacement/retrieval workers and maintenance workers for 
calculating the collective dose. 
3.1 WASTE PACKAGE EMPLACEMENT AND RETRIEVAL OPERATIONS 
The following considerations apply primarily to calculating doses to subsurface emplacement 
and retrieval workers. Some of these methodologies also apply to calculating doses to 
subsurface maintenance workers, as noted in Section 3.2. 
The dose rates at various locations of interest will primarily be due to the gamma and neutron 
radiation emitted from the waste package inside the shielded transporter or from scattered 
radiation leaving the emplacement drifts along the subsurface transport route. The radiation field 
to which operators are exposed from the waste package inside the transporter is assumed to be 
constant for the duration of the transport from the surface until the time the waste package 
transporter moves into an emplacement drift turnout (Assumption 4.2.4). There will be localized 
radiation fields at the turnouts along the waste package transfer route. These locations with 
higher dose rates will occur at the intersections between the main drift and each filled 
emplacement drift (Assumption 4.2.5). Therefore, the dose rate in the main drift along the 
transfer route will vary, peaking whenever the transporter approaches the midpoint of each 
emplacement drift turnout and dropping shortly after the transporter passes the turnout. Thus, in 
addition to the continuous radiation field from the waste package in the shielded transporter, the 
operators are subject to a varying exposure rate along the transfer route. When returning an 
empty transporter to its point of origin, operators are only exposed to this varying exposure rate. 
The average dose rate in both directions along the waste package emplacement or retrieval route 
between the first and last emplacement drift passed by the transporter is calculated simply as a 
distance-weighted average dose rate: 
EDRAv = (EDRTO × NED × DTO)/DED + {EDRMain × [DED – (NED × DTO)]}/DED (Eq. 4) 
where: 
EDRAv = Average dose rate along the emplacement route (mrem/hr) 
EDRTO = Average dose rate in the vicinity of an emplacement drift turnout 
(mrem/hr) 
EDRMain = Average dose rate away from an emplacement drift turnout (mrem/hr) 
DTO = Effective width of an emplacement drift turnout (m) 
DED = Distance between the first and last emplacement drift along the 
route (m) 
NED = Number of emplacement drift turnouts passed by a transporter 
Equation 4 applies to all emplacement routes, including those in which the turnouts are located 
on both sides of the track. Routes through Panels 1, 2, and 4 have turnouts on one side of the 
track (BSC 2003a, Figures 6, 7, and 9). However, turnouts in Panel 3 are located on both sides 
of the track (BSC 2003a, Figure 8), and are offset so that west and east turnout openings are not 
directly across from one another. 

800-00C-SS00-00100-000-00A 10 of 42 February 2004 
The dose rate in the vicinity of an emplacement drift turnout is a function of location along the 
intersection with the access main. Figure 1 shows how this dose may vary as the transporter 
approaches and leaves a turnout area. Note that Figure 1 is used only to illustrate the possible 
dose-rate profile in the vicinity of a typical drift turnout. The numerical values shown in 
Figure 1 are not used as direct inputs to this calculation. 
If dose rates at two or more points along this intersection have been calculated, then a distance 
weighted average dose rate can also be calculated for use as input to Equation 4. Equation 5 
shows how such a distance-weighted average dose rate can be calculated for the four dose points 
shown in Figure 1 along the main access drift in the vicinity of a turnout. 
D3, E3 
D2, E2 
D1, E1 
D0, E0 
0.0 
0.2 
0.4 
0.6 
0.8 
1.0 
1.2 
1.4 
1.6 
1.8 
2.0 
0 5 10 15 20 25 30 35 
Distance (m) 
Dose rate (mrem/hr) 
Figure 1. Hypothetical Dose-Rate Profile in the Vicinity of an Emplacement Drift Turnout 
EDRTO = Si=1,2,3 {[(Ei-1 + Ei )/2] × (Di – Di-1)}/D3 (Eq. 5) 
where: 
Ei = Dose rate at exposure point i (mrem/hr), where i = 1, 2, 3 
Di = Distance from first exposure point (E0), where D0 = 0 (m) and i = 1, 2, 3 
While Equations 4 and 5 represent simplifications of the actual exposure conditions along the 
transport route, they are adequate for purposes of this calculation because the locomotive or 
support equipment is assumed to travel at a constant speed along this route (Assumptions 4.2.9 
and 4.2.10, respectively). This averaging approach is also adequate and consistent with the 
requirement to calculate the total dose to individual workers or group of workers over a full year. 
The time spent by workers traveling in each direction between the first and last emplacement 
drift passed by the transporter is calculated as follows: 
TTO = DED/(1610 × ST) (Eq. 6) 

800-00C-SS00-00100-000-00A 11 of 42 February 2004 
where: 
TTO = Transporter travel time in the emplacement area (hr) 
ST = Transporter speed (mph) 
1610 = Conversion factor (m/mi) 
The time for the transporter to travel between the surface facilities and subsurface emplacement 
area is calculated as follows: 
TS-SS = DS-SS/(1610 × ST) (Eq. 7) 
where: 
TS-SS = Transporter travel time between the surface and subsurface (hr) 
DS-SS = Distance between the surface facility and subsurface emplacement 
area (m) 
3.2 SUBSURFACE MAINTENANCE OPERATIONS 
As indicated in Section 3.1, some of the above considerations extend to the calculation of doses 
to subsurface maintenance workers, including the equations used to calculate time and distance 
inside the access main. Not all of the subsurface areas will be accessible to maintenance 
personnel or require maintenance. The rationale for excluding certain areas from consideration, 
as well as the methodology used to analyze all other maintenance operations and their 
radiological impacts, is summarized below. 
Since maintenance workers will not be transporting a waste package to or from the subsurface, 
the only areas of concern for maintenance worker radiation doses are the intersections between 
the turnouts and access mains. Equipment that requires maintenance, such as the electrical or 
communications equipment, will be placed outside the intersection of the mains and turnouts to 
reduce the exposure to personnel. 
The overhead gantry and antennae in the turnouts (inside the emplacement drift doors) are only 
required for emplacement, so there will be no need to maintain these items after emplacement. 
While they could be operational after emplacement is completed, any operation that takes place 
in the turnout after emplacement will not rely on them being present or operational. These items 
can be replaced remotely if it is determined that retrieval is required. Therefore, there is to be no 
scheduled maintenance on the inside of the emplacement drift door. 
There is no scheduled maintenance for the exhaust mains and these areas will be limited to 
remote observations. Any non-routine maintenance in the turnout or exhaust main will be 
handled similarly to the emplacement drift maintenance. This will involve a campaign to isolate 
the area from the radiation source through temporary shielding or potentially moving waste 
packages (as required) and securing the area before work begins. These openings will be set up 
to eliminate potential maintenance items. For example, the exhaust main is not expected to have 
rail access because there is no requirement for rail in the exhaust, and the rail could require 

800-00C-SS00-00100-000-00A 12 of 42 February 2004 
maintenance. Dose impacts from such non-routine maintenance campaigns are excluded from 
this calculation. 
It is assumed that various maintenance crews will perform different maintenance functions on 
different systems, including ventilation, electrical, mechanical (rail), and ground control 
(Assumption 4.2.12). For example, the ground control inspector will not maintain the ventilation 
louver. 
As specified in more detail in Assumption 4.2.12, the ventilation maintenance crew is expected 
to have three workers: one worker will be responsible for the controls and calibration of controls, 
and two workers will remove and install louvers. The rail (mechanical) maintenance crew is 
expected to have three workers: one worker will be an equipment operator and two workers will 
remove and install rail. The electrical and ground control maintenance crews are each expected 
to have one worker who will perform inspections. 
4. DESIGN INPUT 
4.1 DESIGN CRITERIA 
The following design parameters are either used directly to calculate worker doses or form the 
basis for assumptions listed in Section 4.2. 
4.1.1 Sequence of Operations – Waste Emplacement 
The Emplacement and Retrieval System Description Document (BSC 2003b, Section 4.1.4.1.2, 
pp. 99, 100, 101) describes the waste package transportation and emplacement sequence of 
operations for a typical emplacement drift. This forms the basis for determining the number of 
operators, radiation fields to which they will be exposed, and duration of their exposures. The 
waste emplacement sequence of operations is detailed below: 
1. At the Heavy Equipment Maintenance Building, a single emplacement pallet is loaded 
onto the movable bedplate of the transporter. The bedplate with the pallet is then 
pulled into the shielded enclosure of the transporter. The primary locomotive moves 
the transporter into the load-out area of the DTF or CHF. 
2. Once in the load-out area, the waste package transporter shield doors are opened and 
the emplacement pallet is pushed out of the shielded portion onto the transfer deck 
portion of the transporter. 
3. The emplacement pallet is lifted off the waste package transporter for loading a waste 
package onto the pallet. 
4. A single waste package is placed on the emplacement pallet and then placed back onto 
the transfer deck of the waste package transporter. 
5. The emplacement pallet and waste package are pulled into the shielded enclosure of 
the transporter. 

800-00C-SS00-00100-000-00A 13 of 42 February 2004 
6. The shielding doors are closed. The primary locomotive pulls the loaded transporter 
away from the DTF or CHF docking area. [Note: this step is further broken down into 
two steps in Assumptions 4.2.1 and 4.2.2. Only the second part of this step would 
expose workers to the radiation field of the transporter.] 
7. Stopping at a track turnout outside the DTF or CHF, a secondary locomotive is 
coupled to the transporter. 
8. The entire train is moved through turnouts on the surface to ensure that the waste 
package transporter is correctly oriented for entry into the emplacement drift turnout. 
9. Both locomotives, one in front and one behind, move the loaded transporter into the 
subsurface facilities. 
10. The train stops near the predetermined emplacement drift turnout. 
11. The secondary locomotive in front of the transporter is uncoupled by remote control 
operators and moved to a standby location in the main drift. 
12. The locomotive controls are turned over to remote control operators in the central 
control center at the surface. The on-board locomotive operators then move to a 
designated subsurface location near the emplacement drift. 
13. The ventilation isolation doors at the entrance to the emplacement drift turnout are 
opened, and the rail switch is thrown to the turnout side. 
14. The primary locomotive behind the transporter remotely moves the transporter into the 
turnout and stops before reaching the emplacement drift docking area. 
15. The ventilation isolation doors are closed after the waste package transporter passes. 
16. The shielded transporter enclosure doors are fully opened from the central control 
center. 
17. The locomotive docks the transporter and pushes the transfer deck portion of the 
transporter completely inside the emplacement drift transfer dock. 
18. The rigid chain mechanism pushes the waste package from inside the shielded 
transporter enclosure to the transfer deck portion of the transporter. 
19. The emplacement gantry, which operates on the emplacement drift rails and is also 
remotely operated, moves over the waste package, straddling the transporter’s transfer 
deck. (Note: The gantry is placed in the emplacement drift prior to the start of 
emplacement operations in a particular drift). 
20. The emplacement gantry engages the four support points of the emplacement pallet 
and raises the waste package a few inches above the transporter bedplate. 

800-00C-SS00-00100-000-00A 14 of 42 February 2004 
21. The emplacement gantry is remotely controlled and guided into the emplacement drift 
to the emplacement location for the particular waste package. 
22. The emplacement gantry lowers the waste package to the drift floor and disengages 
from the four support points of the emplacement pallet. 
23. The emplacement gantry is moved back to the emplacement drift entrance for the next 
emplacement operation. 
24. The remote mechanism on the subsurface transporter retracts the bedplate back into 
the transporter’s shielded enclosure. 
25. The locomotive moves the transporter away from the emplacement drift docking area 
and stops. The shielded transporter enclosure doors are closed. 
26. The ventilation isolation doors are opened to allow the waste package transporter to 
pass. 
27. The locomotive moves the transporter from the turnout to the main drift and stops to 
allow the second locomotive to couple to the train. 
28. The ventilation isolation doors are closed after the waste package transporter passes. 
29. The operators reboard the locomotives; the controls are turned back to manual 
operation. 
30. The secondary locomotive is recoupled to the waste package transporter. 
31. The train proceeds to the surface for another emplacement operation. 
The sequence for retrieval operations is essentially the reverse of the sequence for emplacement 
operations. 
Steps 1 through 5 are surface operations that either involve no waste package or are conducted 
remotely with no operator in the vicinity of the transporter. Steps 6 through 12 are conducted 
manually by operators exposed to the radiation field of the shielded transporter on the way from 
surface to subsurface locations. During Step 9, operators are exposed to a varying radiation field 
that peaks as the transporter passes each emplacement drift turnout along the route. As indicated 
above, Steps 13 through 28 are conducted remotely, with the operators moving to a designated 
subsurface location near the emplacement drift where the dose rates will be negligible compared 
to the dose rates to the workers at other steps. In Steps 29 through 31, operators are once again 
exposed to a varying radiation field until the transporter leaves the emplacement area on its way 
to the surface. 
This input is used to derive the number of emplacement and retrieval workers 
(Assumption 4.2.1), and the duration of each step (Assumption 4.2.2) in which the workers may 
be exposed to a radiation field. 

800-00C-SS00-00100-000-00A 15 of 42 February 2004 
4.1.2 Width – Emplacement Drift Turnout 
The width of an emplacement drift turnout is 8 m wide (BSC 2003a, Table 8). 
This input is used in Assumption 4.2.5 to establish the dose-rate profile in the vicinity of turnout 
locations in Panels 1 through 4. 
4.1.3 Layout – Emplacement Drifts in Panels 1 through 4 
Table 1 summarizes the number of emplacement drifts within each of the four waste 
emplacement panels. The table lists the number of emplacement drifts located on the west 
and/or east side of the waste package transporter route through each panel (BSC 2003a, Figures 6 
through 9). 
Table 1. Number of Emplacement Drifts in Panels 1 through 4a 
Emplacement Drifts Emplacement 
Panel 
[A] 
West 
[B] 
East 
[C] 
1 8 0 
2 27 0 
3 22 19 
4 0 30 
Total Number of Drifts: 96 
aSource: BSC 2003a, Figures 6 through 9 
A detailed description of each emplacement panel, including projected development and drift 
turnover sequences, can be found in BSC 2003a (Section 8.4). The detailed description is 
summarized in the following paragraphs. 
The panel numbers correspond to the order in which panel construction and waste emplacement 
will be conducted. The route to the emplacement drifts in Panel 2 requires that the transporter 
goes past turnouts number 3 through 8 in Panel 1, which would already contain waste packages. 
Therefore, 33 turnouts are passed by the transporter en route to emplacement drift number 27 in 
Panel 2. All transporters destined for Panel 3 will require a reversal in the direction just past 
turnout number 3 in Panel 1 in order to head north towards Panel 3. In fact, the transporter will 
likely go past turnout number 3 two times (first southbound, then northbound) en route to Panel 
3. Therefore, a transporter destined for west emplacement drift number 1 in Panel 3 will have to 
travel past 26 turnouts on the west side of the route and 19 turnouts on the east side of the route, 
for a total of 45 turnouts. Panel 4 may be developed from either the north or south side. The 
shortest travel distance to Panel 4 is a route between Panels 1 and 2, with emplacement 
progressing from south to north. The transporter would have to travel a significantly longer 
distance to reach Panel 4 if emplacement occurred from north to south, since the transporter 
would have to travel the entire length of Panel 3 to reach Panel 4. 
This input is used to determine the number of emplacement drifts passed by a worker crew 
(Assumption 4.2.6) and the route that would result in passing the largest number of emplacement 
drifts to or from the emplacement location (Section 4.1.4 and Assumption 4.2.7). 

800-00C-SS00-00100-000-00A 16 of 42 February 2004 
4.1.4 Distance – West Turnout Number 1 in Panel 3 to Turnout Number 3 in Panel 1 
The distance between west turnout number 1 in Panel 3 and turnout number 3 in Panel 1 covers 
the transporter route specified in Section 4.1.3 that passes the greatest number of turnouts, 
assuming Panel 4 is developed from south to north (Assumption 4.2.6). This distance can be 
calculated by adding the length of each branch, delimited by nodes along this route. These nodes 
and branch lengths are obtained from the Ventilation Network Model Calculation (BSC 2003c, 
Attachment A, pp. D-7 to D-8), and the specific input values applicable to this calculation are 
reported in Table 2. Note that the branches are numbered in ascending order starting with west 
turnout number 1 in Panel 3 (Node 3010) and ending with turnout number 3 in Panel 1 (Node 
1030). 
The total length of all these branches is 6,442 ft. Note that the spacing reported in Table 2 
between emplacement drifts located along one side of the route ranges from 268 to 269 ft 
(e.g., Branch 396 between Node 3010 and Node 3020 is 269 ft long). This is consistent (and 
slightly conservative) with the 266-ft minimum emplacement drift spacing (center-to-center) 
criterion (Minwalla 2003, Section 4.11.2.5, p. 234). Multiplying 266 ft by the 24 west-side drift 
intervals between Panel 1, Drift 3, and Panel 3, West Drift 1 results in a total distance of 6,384 ft, 
just one percent less than the input value used in this calculation. This input is used in 
Assumption 4.2.7 to calculate the travel distance through the emplacement area. 
Table 2. Distance between West Turnout Number 1 in Panel 3 and Turnout Number 3 in Panel 1a 
Branch 
Number 
[A] 
Start 
Node 
[B] 
End 
Node 
[C] 
Length 
(ft) 
[D] 
Branch 
Number 
[E] 
Start 
Node 
[F] 
End 
Node 
[G] 
Length 
(ft) 
[H] 
Branch 
Number 
[I] 
Start 
Node 
[J] 
End 
Node 
[K] 
Length 
(ft) 
[L] 
396 3010 3020 269 412 3100 3075 199 428 3145 3180 69 
397 3020 3030 269 413 3075 3110 69 429 3180 3155 199 
398 3030 3040 269 414 3110 3085 199 430 3155 3190 69 
399 3040 3015 199 415 3085 3120 69 431 3190 3165 199 
400 3015 3050 70 416 3120 3095 199 432 3165 3200 69 
401 3050 3025 199 417 3095 3130 69 433 3200 3175 199 
402 3025 3060 70 418 3130 3105 199 434 3175 3210 69 
403 3060 3035 90 419 3105 3140 69 435 3210 3185 199 
404 3035 7214 90 420 3140 3115 199 436 3185 3220 69 
405 7214 3070 90 421 3115 3150 69 437 3220 3195 199 
406 3070 3045 199 422 3150 3125 199 438 3195 1010 69 
407 3045 3080 69 423 3125 3160 69 439 1010 1020 269 
408 3080 3055 199 424 3160 3135 199 440 1020 6112 99 
409 3055 3090 69 425 3135 3170 90 441 6112 1030 169 
410 3090 3065 199 426 3170 7113 90 
411 3065 3100 69 427 7113 3145 90 
Total Length = 6,442 ftb 
aSource: BSC 2003c, Attachment A, pp. D-7 to D-8 
bCalculated by summing the lengths of all branches (reported in Columns [D], [H], and [L] of this table). 

800-00C-SS00-00100-000-00A 17 of 42 February 2004 
4.1.5 Distance – North Portal Entrance to Turnout Number 3 in Panel 1 
As in Section 4.1.4, this distance can be calculated by adding the length of four branches (Branch 
466, 500, 501, and 441), which are delimited by five nodes (Nodes 6110, 6111, 6116, 6112, and 
1030) along this route. The branch lengths are obtained from the Ventilation Network Model 
Calculation (BSC 2003c, Attachment A, pp. D-8 to D-9) and are 6,547, 2,400, 200, and 169 ft, 
respectively. 
The total length of all these branches is 9,316 ft. This input is used in Assumption 4.2.8 to 
calculate the travel distance between the surface facilities and emplacement area. 
4.1.6 External Dose-Rate Criteria – Access Main and Ventilation Door of Emplacement 
Drift Turnout 
In its design options and recommendations, the Dose Rate Calculation for Emplacement Drift 
Turnout Configurations (BSC 2003d, Section 6.4) indicated that “the current dose rate criteria of 
1 mrem/hr in the access main and 10 mrem/hr at the ventilation door … may be overly restrictive 
for the License Application.” It based this conclusion “in view of substantially automated 
emplacement operations, and greatly reduced radiation level for the section of the access main 
shielded by the massive amount of rock.” 
“Pending the outcome of an ALARA evaluation,” the report indicated that “it would be desirable 
to change the dose rate criterion from 1 mrem/hr to 2.5 mrem/hr. Modification to the criterion of 
10 mrem/hr at the ventilation door is not recommended, as maintenance on the ventilation door 
requires periodic human access for hands-on activities.” 
Therefore, this calculation uses 2.5 mrem/hr, rather than 1 mrem/hr, as the dose-rate criterion in 
the access main at the entrance to an emplacement drift turnout. This calculation retains the 
10 mrem/hr dose-rate criterion for locations immediately outside the ventilation doors. 
This input is used in Assumptions 4.2.5 and 4.2.13 to derive the dose rates to workers located in 
the vicinity of emplacement drift turnouts. 
4.1.7 External Dose Rate – 10 Meters from Loaded Waste Package Transporter 
The external dose rate is 3.71 mrem/hr at a distance of 10 meters from the surface of a loaded 
waste package transporter when a waste package containing design basis fuel is inside the 
shielded enclosure. This value is taken from the Waste Package Transporter Shielding Design 
Calculation (BSC 2004, Table 6.3-1). 
This input is used in Assumption 4.2.3 to estimate the dose rate to workers involved in coupling 
a locomotive to a loaded waste package transporter. 
4.1.8 Maximum Speed – Waste Package Transporter and Support Equipment 
Per the description of the Main Drift Grade in the Emplacement and Retrieval System 
Description Document (BSC 2003b, Section 3.1.3.1.2), vehicles operating in the main drift shall 

800-00C-SS00-00100-000-00A 18 of 42 February 2004 
not exceed a “maximum normal operating speed of 5 mph for the waste package transporter and 
8 mph for support equipment.” 
This input is used to derive the speed of the waste package transporter (Assumption 4.2.9) and 
maintenance support vehicle (Assumption 4.2.10). 
4.2 ASSUMPTIONS 
The following assumptions are used to calculate worker doses. 
4.2.1 Number of Workers – Emplacement and Retrieval Operations 
The estimated number of workers is based on engineering judgment and follows the sequence of 
operations described in Section 4.1.1. Table 3 lists the number of workers required to perform 
each step in which workers are exposed to radiation during emplacement and retrieval 
operations. 
Table 3. Number of Workers Required to Perform Emplacement and Retrieval Steps 
Step Number 
(Section 4.1.1) 
[A] 
Number of 
Workers 
[B] 
Rationale 
[C] 
1, 2, 3 
N/A – No or 
Low Radiation 
Field 
These steps are conducted in a zero or very low radiation field; workers 
receive a negligible dose from these steps. 
4, 5, 6a 
N/A – Remote; 
Operators in 
Low Radiation 
Field 
These steps are conducted remotely in radiation fields; no workers are 
present in the vicinity of the operations and receive zero doses from these 
steps. 
6b 2 This step involves operating a primary locomotive with a two-person crew 
(W1/W2). 
7 4 
The two-person crew of the secondary locomotive (W3/W4) performs this 
step; the crew of the primary locomotive (W1/W2) stays in the cab during this 
operation. The dose rates to W3/W4 are higher than the dose rates to 
W1/W2 due to their proximity to the waste package transporter and absence 
of any cab shielding. 
8, 9, 10, 11 4 These steps involve two locomotives, each with a two-person crew 
(W1/W2/W3/W4). 
12 2 
The crew of the primary locomotive performs this task (W1/W2). The crew of 
the secondary locomotive (w3/W4) has moved to standby location as a result 
of Step 11. 
13, 14, 15, 16, 
17, 18, 19 , 20, 
21, 22, 23, 24, 
25, 26, 27, 28 
N/A – Remote; 
Operators in 
Low Radiation 
Field 
These steps are conducted remotely in radiation fields; no workers are 
present in the vicinity of these operations. All workers are standing by in a 
location with very low radiation fields during these steps and receive 
negligible doses. 
29, 30, 31 4 All four locomotive operators (W1/W2/W3/W4) are involved in these steps, 
conducted without a waste package in the transporter. 
N/A: Not applicable 
For some steps, workers will not be significantly exposed either because the activity is conducted 
remotely, or because the activity occurs away from any radiation field. In those cases, the 
number of workers is listed as N/A because no significant dose is incurred in those steps. In the 

800-00C-SS00-00100-000-00A 19 of 42 February 2004 
worker dose calculations (Section 6.1.1), the two crew members of the primary locomotive are 
identified as W1/W2, and the two crew members of the secondary locomotive are identified as 
W3/W4. 
Rationale: The rationale for the number of involved workers is given in the last column of 
Table 3. 
Usage: These assumptions are used in Section 6.1.1. 
4.2.2 Exposure Duration – Emplacement and Retrieval Operations 
The time spent by workers in the radiation fields for each of the steps in Section 4.1.1 is based on 
engineering judgment or is calculated in Section 6.1.1. These times are listed in Table 4 for each 
step. As was the case for Assumption 4.2.1, in some steps workers will receive a negligible dose 
because the activity is conducted remotely, or because the activity occurs in very low radiation 
fields. In those cases, the exposure duration is listed as N/A because no significant worker doses 
are incurred in those steps. 
Rationale: The rationale for the amount of time spent in the radiation field is given in the last 
column of Table 4. These times are difficult to quantify accurately in the absence of actual 
operational data. However, the times chosen are considered to be overestimates, resulting in a 
conservative dose calculation. 
Usage: These assumptions are used in Section 6.1.1. 
4.2.3 Dose Rate – At Coupling Location (Loaded Waste Package Transporter) 
The operators that manually couple the secondary locomotive to a loaded waste package 
transporter are assumed to perform this operation at a distance of 10 m from the nearest surface 
of the shielded enclosure. At this distance, the calculated dose rate from a shielded design basis 
waste package is 3.71 mrem/hr (see Section 4.1.7). 
Rationale: Ten meters is a conservative distance based on the transporter dimensions and 
secondary locomotive coupling location shown in Figure 2. 
End-to-end transporter dimensions are 78 ft 11.25 in. (24 m), and the length of the shielded 
enclosure is 21 ft 11 in. (6.7 m). The primary locomotive coupling location is approximately 
five meters from the nearest surface of the shielded enclosure. However, the only coupling 
operation performed by operators when a waste package is present inside the shielded enclosure 
involves the secondary locomotive (Section 4.1.1). 
The use of the dose rate for a design basis waste package is conservative. As indicated in 
Assumption 4.2.15, the dose rates from an average waste package inside the shielded enclosure 
would be at least a factor of five times lower. 
Usage: This assumption is used in Section 6.1.1 to calculate the dose to workers performing the 
coupling operations when a dose package is present inside the waste package transporter (Step 7 
in Section 4.1.1). 

800-00C-SS00-00100-000-00A 20 of 42 February 2004 
Table 4. Time Spent by Workers to Perform Emplacement and Retrieval Steps 
Step Number 
(Section 4.1.1) 
[A] 
Time in 
Radiation Field 
(hr) 
[B] 
Rationale 
[C] 
1, 2, 3 N/A – No or Low 
Radiation Field 
These steps are conducted in a zero or very low radiation field. Therefore, the 
time to conduct these operations is not relevant or needed for the purpose of 
this design calculation. 
4, 5, 6a 
N/A – Remote; 
Operators in Low 
Radiation Field 
These steps are conducted remotely in relatively high radiation fields; no 
workers are present in the vicinity of these operations or radiation fields. In 
addition, it is assumed that any dose-rate monitoring of the waste package 
transporter radiation field will be conducted remotely (e.g., using portal 
monitors). Therefore, the time to conduct these steps is not needed for the 
purpose of this design calculation. 
6b 0.1 
This step is estimated to take no longer than 1/10th of an hour (6 minutes), the 
smallest increment of time considered in this calculation due to the uncertainties 
in the time estimates. This assumption is based on engineering judgment. 
7 0.5 This step is estimated to take half an hour based on engineering judgment. 
8 0.1 This step is estimated to take no longer than 1/10th of an hour based on 
engineering judgment. 
9 
Variable – 
Calculated in 
Section 6.1.1 
The total time for this step is the sum of the travel time from the surface turnouts 
to the North Portal, travel time from the North Portal to an emplacement panel, 
and travel time through the emplacement panel to the emplacement drift. Each 
segment is calculated separately in Section 6.1.1 because the radiation fields 
vary along the route. 
10 
.0 
(included in 
Step 9) 
The train’s stoppage distance (and time) from full speed has not been 
determined, but is estimated to be considerably less than 1/10th of an hour. The 
two locomotive crews begin their exposure to the radiation field in the 
emplacement drift turnout area, but this initial time is factored into the travel time 
calculation for Step 9 by including the destination emplacement drift in the 
number of drifts passed by the transporter en route to its destination. 
11 0.5 
Time is based on the assumption that the same amount of time is needed to 
uncouple and maneuver the second locomotive to the standby location as is 
needed to couple the locomotive in Step 7. However, in this case, the 
uncoupling is performed remotely while the two locomotive crews stay in their 
cabs. In addition, the uncoupling operation is assumed to occur outside the 
radiation field of the turnout. 
12 
.0 
(negligible 
duration) 
Turning over control to the remote operator, and the operators moving to the 
standby location, is assumed to take less than one minute. 
13, 14, 15, 16, 17, 
18, 19, 20, 21, 22, 
23, 24, 25, 26, 27, 
28 
N/A – Remote; 
Operators in Low 
Radiation Field 
These steps are conducted remotely in radiation fields; no workers are present 
in the vicinity of these operations or radiation fields. All workers are standing by 
in a very low radiation field during these steps and receive a negligible dose. 
Therefore, the time to conduct these operations is not relevant or needed for the 
purpose of this design calculation. 
29 0.1 
Switching both locomotives back to manual mode is estimated to take less than 
1/10th of an hour. This step includes the time it takes for the crew of the second 
locomotive to approach the waste package transporter prior to coupling. 
30 N/A – Negligible 
Radiation Field 
Coupling the second locomotive is assumed to occur at a standby location that 
is far enough removed from the turnout entrance, a location where the dose 
rates are negligible. 
31 
Variable – 
Calculated in 
Section 6.1.1 
The total time for this step is the sum of the travel time from the emplacement 
drift through the emplacement panel, travel time from an emplacement panel to 
the North Portal, and travel time from the North Portal to the surface facility. 
Each segment is calculated separately in Section 6.1.1 because the radiation 
fields vary along the route. 
N/A: Not applicable 

800-00C-SS00-00100-000-00A 21 of 42 February 2004 
4.2.4 Dose Rate – Inside Locomotive Cab 
The locomotive cabs are assumed to be shielded, if necessary, so that the dose rate to operators 
inside the cabs will not exceed 2.5 mrem/hr when the locomotive is coupled to a transporter 
containing a waste package inside the shielded enclosure. 
Rationale: The Project Design Criteria Document (Minwalla 2003, Table 4.9.1-1) lists as one of 
its criteria the requirement that the individual annual TEDE not exceed 5,000 mrem, consistent 
with the requirements in Section 4.3 of this calculation. While operators will not be in the 
locomotive cab continuously, they would spend a good portion of the emplacement or retrieval 
operation inside the cab. A dose-rate limit of 2.5 mrem/hr inside the cab ensures that even if the 
operators were to spend a full work year inside the cab (2,000 hrs per work year), their exposure 
would not exceed 5,000 mrem from design basis waste packages. 
The use of this dose-rate criterion (for a design basis waste package) is conservative. As 
indicated in Assumption 4.2.15, the dose rates inside the transporter cab from an average waste 
package inside the shielded enclosure would be at least a factor of five times lower. 
The dimensions of the locomotive and waste package transporter are provided in Figure 2. The 
distance between the rear wall of the cab and rear hitch, to which the waste package transporter 
would be attached, is approximately 9 m. The distance to the nearest surface of the waste 
package transporter’s shielded enclosure is approximately 14 m (9 m + 5 m, see 
Assumption 4.2.3). Since the secondary locomotive is dimensionally identical to the primary 
locomotive, this assumption is even more conservative since the second locomotive’s cab would 
be at a greater distance (approximately 21 m) from the nearest surface of the shielded enclosure. 
Figure 2. Waste Package Transporter and Two Locomotives 
Usage: This assumption is used in Sections 3.1 and 6.1.1 to calculate the dose to workers inside 
the locomotive cabs while a transporter containing a waste package is coupled to one or both 
locomotives (Steps 6 through 12 described in Section 4.1.1). 
4.2.5 Dose Rate - Vicinity of Turnout Locations 
The dose rates at the turnout locations along the main access routes are assumed to be equal to 
the 2.5 mrem/hr dose-rate criterion over the entire 8-m width of the turnout opening (per 
Sections 4.1.6 and 4.1.2, respectively). The dose rate is assumed to linearly drop to negligible 
levels along the access main within 8 m on either side of the turnout opening, resulting in an 

800-00C-SS00-00100-000-00A 22 of 42 February 2004 
effective opening that is 24 m wide. This dose-rate profile is illustrated graphically in Figure 3, 
with points labeled in a similar manner as in Figure 1. 
D1, E1 D2, E2 
D0, E0 D3, E3 
0 
0.5
1 
1.5
2 
2.5
3
0 4 8 12 16 20 24 28 
Distance (m) 
Dose rate (mrem/h) 
Figure 3. Assumed Dose-Rate Profile in the Vicinity of an Emplacement Drift Turnout 
Rationale: This simplifying and conservative assumption is appropriate to estimate average dose 
rates along the waste package transporter route. The access main dose-rate criterion 
(Section 4.1.6) is driven by dose calculations using design basis waste packages placed near an 
emplacement drift entrance. No direct radiation reaches the workers outside the emplacement 
drift, and the entire dose is contributed by scattered radiation. Moving along the transporter 
route away from this centrally located dose point, the dose rate drops to a negligible level as the 
repository rock matrix shields most of the scattered radiation originating from waste packages 
inside the emplacement drift. This is supported by the conclusion in Section 4.1.6, “in view of 
… (the) greatly reduced radiation level for the section of the access main shielded by the massive 
amount of rock.” 
In addition, the average dose rates at the turnout locations are expected to be significantly lower 
due to the bounding considerations inherent in using design basis waste packages to derive the 
access main dose-rate criteria. Finally, any shielding used in the locomotive cab to reduce the 
exposure to workers from a loaded waste package transporter should also be effective at reducing 
the radiation field around the turnout locations. In this calculation, no credit is taken for any cab 
shielding that would reduce the radiation field in the vicinity of emplacement drift turnouts. 
Usage: This assumption is used in Sections 3.1 and 6.1.1, along with Equations 4 and 5, to 
calculate mean dose rates to workers (including maintenance workers) traveling along the 
transporter route. It is also used in estimating doses from operations that take place in the 
vicinity of an emplacement drift turnout (Steps 9 through 12 and Steps 29 through 31 described 
in Section 4.1.1), as well as maintenance operations in these areas. 

800-00C-SS00-00100-000-00A 23 of 42 February 2004 
4.2.6 Maximum Number of Emplacement Drift Turnouts Passed by Vehicle – 
Emplacement/Retrieval and Maintenance Operations 
The emplacement route that would result in the highest dose to either emplacement/retrieval or 
maintenance workers in any year of operation is assumed to be between West Turnout Number 1 
in Panel 3 and Turnout Number 3 in Panel 1, since this route involves passing 45 emplacement 
drifts. 
Rationale: This assumption is based on the layout of the emplacement drifts summarized in 
Section 4.1.3. A route maximizing the number of turnouts passed by the waste package 
transporter (or maintenance crew support vehicle) and the amount of time it takes the vehicles to 
reach their destination is assumed to maximize the dose to workers. A north-to-south route 
through Panel 4 may result in higher annual doses to workers since this routing would require 
traversing all of Panel 3. However, a south-to-north emplacement route in Panel 4 is considered 
more likely as it would reduce the distance the transporter would have to travel to reach the 
average emplacement drift in Panel 4. While the length of Panel 4 is greater than the length of 
Panel 3, only 30 turnouts are located in Panel 4 compared to the 45 turnouts passed by a 
transporter en route to the last emplacement drift in Panel 3. In addition, the route to Panel 3 
requires the transporter to reverse directions in the Panel 1 area. The time needed to perform this 
operation may offset some of the additional travel time spent by a transporter en route to the final 
emplacement drift in Panel 4. 
Usage: This assumption is used in Sections 6.1.1 and 6.2.1, along with Equation 4, to calculate 
average dose rates along this route. 
4.2.7 Travel Distance – Through Emplacement Area 
The dose-maximizing distance through an emplacement area in any year is assumed to be 
between west turnout number 1 in Panel 3 and turnout number 3 in Panel 1. This distance is 
1,964 m. 
Rationale: The total travel length was reported as 6,442 ft in Section 4.1.4 and converted to 
meters (0.3048 m/ft). This assumption represents an overestimate since it does not take credit 
for more than one emplacement drift filled per year (Assumption 4.2.11). Therefore, the average 
travel distances through Panel 3 will always be less than this estimate since only the last 
emplacement drift in Panel 3 is located at this dose-maximizing travel distance. 
Usage: This assumption is used in Section 6.1.1, along with Equations 4 and 6, to calculate 
average dose rates and travel times along this dose-maximizing route. 
4.2.8 Travel Distance – Between Surface Facilities and Emplacement Area 
The distance traveled by the waste package transporter between the surface facilities and 
emplacement area is assumed to be 3,540 m. 
Rationale: The layout of the surface facilities, including the total length of the tracks between 
surface and subsurface facilities, has not been finalized. Therefore, this value is based on a 
conservatively estimated distance of 700 m between the surface facilities and North Portal, plus 

800-00C-SS00-00100-000-00A 24 of 42 February 2004 
2,840 m between the North Portal and turnout number 3 in Panel 1. The first segment (surface 
facilities to North Portal) is based on an approximate rail length of 2,000 ft between DTF-2 and 
the North Portal shown on the Geological Repository Operations Area North Portal – Site Plan 
(BSC 2003e), plus a 10 percent contingency, converted to meters (0.3048 m/ft). Other surface 
facilities (DTF-1 and CHF) will likely involve shorter rail distances to the North Portal. The 
second segment (North Portal to emplacement area) was reported as 9,316 ft in Section 4.1.5 and 
converted to meters (0.3048 m/ft). 
Usage: This assumption is used in Section 6.1.1, along with Equation 7, to calculate travel times 
along the transporter route. 
4.2.9 Travel Speed – Waste Package Transporter 
The waste package transporter is assumed to travel at an average speed of 4 mph. 
Rationale: As indicated in Section 4.1.8, the maximum normal operating speed of the waste 
package transporter is 5 mph. Travel times (and exposure duration) are minimized when the 
waste package transporter travels at this maximum speed. However, it is not conservative or 
realistic to assume that the fully loaded transporter will be able to sustain this speed over the 
entire route, since some routes require the transporter to stop and reverse directions. Therefore, a 
conservative assumption is made that the average transporter speed is 4 mph. Operating the 
transporter at slower speeds would increase the travel time and worker exposures, but there are 
operational incentives to run the transporter at the highest possible safe speed. Therefore, a 
value that is 20 percent below the maximum allowable transporter speed is considered to be 
realistic for purposes of this calculation. 
Usage: This assumption is used in Sections 3.1, 6.1.1, and 6.2.1, along with Equations 6 and 7, 
to calculate travel times along the transporter route. 
4.2.10 Travel Speed – Support Equipment 
The travel speed for support equipment is assumed to be 8 mph. 
Rationale: The maximum allowable speed for support equipment specified in Section 4.1.8 
provides a realistic estimate for the calculation of doses to maintenance workers when in transit 
to the work locations. While slower speeds would result in more conservative dose estimates, 
there are operational incentives to run the support vehicle at the highest allowable safe speed. In 
addition, the dose contribution from transit through the emplacement panels is much smaller than 
the doses incurred during the actual maintenance operations (see Section 6.2.1). Therefore, the 
total doses are not very sensitive to the value of this parameter. 
Usage: This assumption is used in Sections 3.1 and 6.2.1, along with Equation 6, to calculate 
travel times through an emplacement panel. 
4.2.11 Number of Crews/Waste Packages – Emplacement and Retrieval Operations 
The number of waste packages emplaced each year is assumed to be less than or equal to 600. A 
minimum of two work shifts would be required to accommodate this throughput. It is, therefore, 

800-00C-SS00-00100-000-00A 25 of 42 February 2004 
assumed that each crew will transport an average of 300 waste packages annually to or from the 
emplacement drifts during years in which this maximum assumed throughput is effective. At 
this emplacement rate, five drifts would be subject to emplacement operations in one year. 
Rationale: The peak emplacement rate assumption of 600 waste packages per year is consistent 
with the assumption contained in the Recommended Surface Contamination Levels for Waste 
Packages Prior to Placement in the Repository (Edwards and Yuan 2003, Section 4.2.2) and is 
conservative compared to Cloud 2003 (Table 4). It represents an upper bound estimate of the 
annual waste-package emplacement rate. 
The number of active drifts in one year, at a rate of 600 waste packages emplaced per year, is 
based on: 
• Average emplacement drift length of 692 m, based on 66,450 m total drift length (BSC 
2003a, Table 8) and 96 drifts (Table 1) 
• Design basis waste package length of 202.7 in. (5.25 m) (BSC 2003b, Table 3) 
• Average spacing (skirt-to-skirt) of 4 in. (0.10 m) between waste packages (BSC 2003b, 
Section 3.1.2.2.3). 
This results in 132 waste packages per average drift, or an average of 4.6 drifts (rounded up to 5 
for conservatism) per year in which 600 waste packages are emplaced. 
It is assumed to take between four and eight hours to emplace or retrieve a single waste package. 
In order to handle two waste packages in a day, at least two emplacement and retrieval crews 
(and possibly a partial third crew, if the first two crews are limited to a 250-day work year with 
no overtime) would be needed. For conservatism in calculating individual doses, only two crews 
are assumed to be required for this operation. 
Usage: This assumption is used in Section 6.1, along with Equations 1 and 3, to calculate 
individual and collective doses to emplacement and retrieval workers. 
4.2.12 Crew Size, Duration, and Frequencies – Maintenance Operations 
A list of operational steps has not been formally developed for each of the subsurface 
maintenance operations. Therefore, the sequence of operations for such activities is listed here 
as a series of assumptions based on engineering judgment. Table 5 summarizes the crew-size 
assumptions and the estimated duration and frequencies of ventilation, electrical, mechanical 
(rail), and ground control maintenance operations. 
These operations are further broken down into component steps in the discussion of the rationale 
for each operation. The first worker in each crew is identified as W1 and, where applicable, the 
second and third workers in a crew are identified as W2 and W3, respectively. 

800-00C-SS00-00100-000-00A 26 of 42 February 2004 
Table 5. Duration, Crew Size, and Frequency for Various Maintenance Operations 
Maintenance Operation 
[A] 
Crew Size 
[B] 
Duration (hrs) 
[C] 
Operations per Year 
[D] 
Ventilation 3 3.2 10 
Electrical 1 3.5 12 
Mechanical 3 8 5 
Ground Control 1 8 2 
Rationale (Ventilation System Maintenance): There is no planned maintenance for the door 
actuator. The actuator will only be needed to operate a few hundred times during emplacement 
(based on approximately 132 waste packages per drift [see Assumption 4.2.11]). The actuator 
will be remotely tested to see if it is operational and, if found to be inoperable, it can be replaced 
(when access is required) using similar procedures to maintenance in the turnout (e.g., using 
temporary shielding). The failure rate on the actuator is expected to be very low. 
The only planned maintenance will be on the louver, which is a bolt-on item. It is estimated that 
maintenance will be required every 10 years. With 96 full drifts (see Table 1), this corresponds 
to approximately 10 maintenance operations per year. 
The ventilation crew is estimated at three workers: 
• One worker to disconnect, calibrate, and reconnect controls (W1) 
• Two workers to remove and install louvers (W2, W3). 
A detailed breakdown of the estimated work process for ventilation system maintenance is: 
• 0.25 hr to mobilize and set up (W1, W2, W3) 
• 0.50 hr to disconnect controls (W1) 
• 0.50 hr to unbolt and remove louver (W2, W3) 
• 0.50 hr to reinstall the louver (W2, W3) 
• 0.50 hr to reconnect and calibrate controls (W1) 
• 0.25 hr to demobilize (W1, W2, W3). 
Total time: 2.5 hrs plus 1/3 contingency for level of the estimate, or 3.2 hrs (approximately half 
a shift per operation). Therefore, the total time per year spent on ventilation system maintenance 
would be 32 hrs per worker, or 96 total staff-hrs, excluding travel time to the work location. 
When only one or two workers are performing a given task, the other(s) is assumed move to the 
access main where the dose rate is lower. Therefore, all three workers spend a total of 1.5 hrs, 
plus contingency (or 2 hrs), at the door. The balance of the time is spent in the access main. 
Rationale (Electrical System Maintenance): There will be no required scheduled maintenance on 
the transformers that would increase the worker dose because of where they are located. The 
motor on the door will require maintenance while emplacement is ongoing. With minimal 
access required after emplacement, there will be no scheduled maintenance after emplacement is 
completed. The motor will be tested remotely, similar to the actuator, and follow similar 
procedures. While emplacement is ongoing, it is estimated that each motor will require 
maintenance each month. The emplacement rate is approximately five drifts per year 
(Assumption 4.2.11). Based on the expected thermal loading of the drifts, it is conservatively 

800-00C-SS00-00100-000-00A 27 of 42 February 2004 
estimated that seven drifts could require maintenance during any given month (allowing for two 
spare drifts). Although all the work would be conducted at the door, it should be noted that dose 
rates are based on loaded drifts, so the majority of the maintenance work being performed would 
actually be under substantially lower dose rates from partially filled drifts. 
A detailed breakdown of the estimated work process is: 
• 0.25 hr to inspect connections (W1) 
• 0.25 hr to inspect and maintain lubrication (W1). 
Total time: 0.5 hr per drift. Assuming seven drifts are inspected each month results in a total of 
3.5 hrs per inspection-month. Therefore, the total work would be 42 hrs per year (42 total 
staff-hrs), excluding travel time to the work location. 
Rationale (Mechanical System Maintenance): Rail maintenance will not be required. However, 
after emplacement is complete, the switches to the emplacement drifts will be removed to reduce 
the potential of derailments and to minimize maintenance. The switch area will be made of 
concrete to expedite the change over. By using concrete in the intersection, the potential for 
derailments of the transporter and time spent in the area is reduced, which would substantially 
reduce the overall worker dose. Approximately five drifts will be filled per year, so five 
switches would be removed each year. 
The rail (mechanical) crew is estimated at 3 workers: 
• One equipment operator (W1) 
• Two workers to remove and install rails (W2, W3). 
A detailed breakdown of the estimated work process is: 
• 0.25 hr to mobilize and set up 
• 1.00 hr to unbolt switch 
• 2.00 hrs to remove frog and switch assemble (with a forklift) 
• 1.00 hr to remove old rail and move new section into work area 
• 1.00 hr to cut and drill hole to fit new section of rail into place 
• 0.50 hr to install new rail 
• 0.25 hr to demobilize. 
Total time: 6 hrs plus 1/3 contingency for level of the estimate, or 8 hrs (one shift per operation). 
Therefore, the total time spent on mechanical (rail) maintenance would be 40 hrs per worker, or 
120 total staff-hrs, excluding travel time to the work location. All maintenance operations would 
be conducted in the access main in the vicinity of the turnouts; therefore, all three workers are 
subject to the same dose rates. 
Note that the estimate for changing out a switch from a ballast roadbed is two to three shifts, 
versus one shift for changing out a switch from a concrete roadbed. 
Rationale (Ground Control System Maintenance): Ground control will be installed to minimize 
maintenance; therefore, there is no planned ground control maintenance. Any maintenance that 

800-00C-SS00-00100-000-00A 28 of 42 February 2004 
may occur can be handled similarly to the unplanned work in the turnout using, for example, 
temporary shielding. The only exposure to the ground control crew would be when conducting 
planned inspections. In areas that are inaccessible to humans (e.g., turnouts, emplacement drift, 
and exhaust main), inspections will be done remotely. Inspections in the intake mains can be 
done manually. The intersections will be monitored using extensiometers, so the frequency of 
manual inspections can be reduced. It is estimated that each intersection will be inspected twice 
per year by one person. There are 96 drifts (see Table 1) to be inspected, which will be done 
from the rail as the inspector slowly travels through the mains. 
It is estimated to take five minutes to inspect each of 96 intersections. 
Total time: 8 hrs per inspection. Therefore, the total work would be 16 hrs per year (16 total 
staff-hrs), which includes travel time. 
Usage (applies to all maintenance/inspection operations): These assumptions are used in 
Sections 3.2, 6.2.1, and 6.2.2, along with Equations 2 and 3, to calculate individual and collective 
doses to maintenance workers. 
4.2.13 Dose Rates – Maintenance Operations 
The assumed dose rates at each maintenance location are listed in Table 6, along with the 
rationale for these assumptions. 
Table 6. Dose Rates at Various Maintenance Operations Locations 
Maintenance 
Location 
[A] 
Dose Rate 
(mrem/hr) 
[B] 
Maintenance 
System 
[C] 
Rationale 
[D] 
Intersection of 
Turnouts and Access 
Main 
2.5 
Ventilation 
Mechanical 
Ground Support 
Per Section 4.1.6 and Assumption 4.2.5 of this 
calculation. Applies to ventilation system 
personnel standing by while others are 
performing work at the emplacement drift door. 
Emplacement Drift 
Vent Door 10 Ventilation 
Electrical 
Per criteria in Section 4.1.6. Applies to 
ventilation system only for time spent at the 
emplacement drift door. 
Transport Route 
through Emplacement 
Panel 
Calculated in 
Section 
6.2.1 
Ventilation 
Electrical 
Mechanical 
Calculated using Equation 4. 
Rationale: See last column in Table 6 for the rationale applicable to each maintenance location. 
Usage: These assumptions are used in Section 6.2.1, along with Equation 2, to calculate 
individual doses to maintenance workers. 
4.2.14 Interaction between Emplacement/Removal and Maintenance Operations 
Operations involving emplacement or retrieval of waste packages are assumed to be conducted at 
different times from operations involving subsurface facility maintenance. 
Rationale: Maintenance operations occur at a relatively low frequency (Assumption 4.2.12). 
The emplacement and retrieval operations, while performed more frequently 

800-00C-SS00-00100-000-00A 29 of 42 February 2004 
(Assumption 4.2.11), allow maintenance crews to enter the repository to conduct operations at 
times and/or locations when or where no waste packages are in the process of being emplaced or 
retrieved. Therefore, it is reasonable to assume that any radiation fields due to emplacement and 
retrieval operations (e.g., from a waste package inside a shielded transporter en route to an 
emplacement drift) will not add to the doses calculated for maintenance workers. 
Usage: This assumption is used throughout Section 6 to calculate individual doses to all 
subsurface workers. 
4.2.15 Dose-Rate Reduction Factor – Design Basis Waste Package to Average Waste 
Package 
The average dose-rate reduction factor between the design basis waste package and average 
waste package is assumed to be five. 
Rationale: The basis for this scaling factor is provided in Attachment I to this calculation. The 
exposure geometry between workers and waste packages (either on the transporter or in an 
emplacement drift) is primarily along the waste package axial direction. That is, the workers are 
exposed primarily by radiation leaving the tops or bottoms of waste packages (axial direction), 
rather than radiation emitted from the sides (radial direction). All the calculated scaling factors 
for the axial geometry discussed in Attachment I (Table I-1) range from 5.52 to 6.74. Therefore, 
an average factor of five applied to all conditions is conservative. 
Usage: This assumption is used throughout Section 6 to calculate average annual individual and 
collective doses to all subsurface workers. 
4.3 REGULATIONS 
The regulation applicable to worker doses is contained in 10 CFR 20.1201, Occupational Dose 
Limits for Adults: 
(a) The licensee shall control the occupational dose to individual adults to the following 
dose limits: 
(1) An annual limit, which is the more limiting of: 
(i) The total effective dose equivalent being equal to 5 rems; 
or 
(ii) The sum of the deep-dose equivalent and the committed dose equivalent to 
any individual organ or tissue other than the lens of the eye being equal to 
50 rems. 
(2) The annual limits to the lens of the eye, to the skin, and to the extremities, which 
are: 
(i) A lens dose equivalent of 15 rems, and 
(ii) A shallow-dose equivalent of 50 rems to the skin or to any extremity. 

800-00C-SS00-00100-000-00A 30 of 42 February 2004 
4.4 CRITERIA 
As low as is reasonably achievable (ALARA) design goals (Minwalla 2003, Sections 4.9.3.2 and 
4.9.3.3) for occupational workers ensure that both individual and collective annual doses are 
maintained at ALARA levels during normal operations and as a result of Category 1 event 
sequences. 
The following ALARA design goal is established for the design process: 
• The ALARA design goal for individual radiation worker doses is to minimize the 
number of individuals that have the potential of receiving more than 500 mrem/yr 
TEDE. That goal is 10 percent of the annual TEDE limit in 10 CFR 20.1201, and 
includes both internal and external exposures. 
5. USE OF SOFTWARE 
5.1 BASELINED SOFTWARE 
No software subject to verification under AP-SI.1Q, Software Management, was used in this 
design calculation. 
5.2 COMMERCIAL OFF-THE-SHELF SOFTWARE 
Only commercial off-the-shelf software was used in this calculation. 
5.2.1 Microsoft Excel 97 SR-2 
• Title: Excel 
• Version/Revision Number: Microsoft® Excel 97 SR-2 
• This version is installed on a Dell OptiPlex GX270 PC running the Microsoft 
Windows 2000 operating system (property tag YMP000730). 
Microsoft Excel 97, a spreadsheet program, is used in this calculation. Excel was used to 
generate tables listing the emplacement, maintenance, and retrieval operations; travel distances; 
number of workers involved in each operation; dose rates at worker locations; and time spent by 
the workers in the radiation field at each location. Excel was also used to generate the dose-rate 
profiles shown in Figures 1 and 3. Methodologies and equations (derived in Section 3), design 
parameters and assumptions (listed in Section 4), and calculations (performed in Section 6) are 
documented in sufficient detail to allow for independent duplication of the various computations 
without recourse to the originator or the original spreadsheet. Per Section 2.1.6 of AP-SI.1Q, 
this software is considered exempt. 

800-00C-SS00-00100-000-00A 31 of 42 February 2004 
6. CALCULATION 
Individual and collective worker doses are calculated by applying equations and methodologies 
described in Section 3 and by using design inputs defined in Section 4. Doses to emplacement 
and retrieval workers are calculated in Section 6.1, while doses to maintenance workers are 
calculated in Section 6.2. 
Calculated values are presented (rounded) only to the appropriate number of significant digits; 
however, calculations using Excel are carried out without regard to the number of significant 
digits in order to reduce round-off error between steps. 
6.1 EMPLACEMENT AND RETRIEVAL WORKER DOSES 
Annual doses to individual emplacement and retrieval workers are calculated in Section 6.1.1. 
These doses are then summed in Section 6.1.2 to calculate the collective dose to this group of 
workers. 
6.1.1 Individual Worker Doses – Emplacement or Retrieval Operations 
The anticipated sequence of emplacement operations is described in Section 4.1.1. The number 
of workers (Assumption 4.2.1) and exposure duration (Assumption 4.2.2) used in calculating the 
doses for each operational step are listed in Tables 3 and 4, respectively. The exposure times for 
operational Steps 9 and 31 are calculated as follows. 
Step 9 includes travel time from the surface turnouts to the North Portal and from the North 
Portal to an emplacement panel (Step 9a). The transporter then travels through the emplacement 
panel to the emplacement drift (Step 9b). Because the radiation fields vary along the route, each 
segment is calculated separately as follows: 
• Step 9a: Use Equation 7, TS-SS = DS-SS/(1610 × ST), where DS-SS = 3,540 m 
(Assumption 4.2.8) and ST = 4 mph (Assumption 4.2.9). TS-SS = 3540/(1610 × 4) = 
0.55 hr. 
• Step 9b: Use Equation 6, TTO = DED/(1610 × ST), where DED = 1,964 m 
(Assumption 4.2.7) and ST = 4 mph (Assumption 4.2.9). TTO = 1964/(1610 × 4) = 
0.30 hr. 
On the return trip through the emplacement area (Step 31a), the same transit time (0.30 hr) would 
apply. Since any dose rates to workers outside the emplacement area are negligible when the 
transporter does not contain a waste package, the travel time to return to the surface (Step 31b) is 
not required for this calculation. 
The dose field to which workers are exposed in Step 9a is 2.5 mrem/hr (Assumption 4.2.4) since 
the locomotive operators are assumed to be inside the cab, and the only contribution to the dose 
is from the waste package inside the transporter’s shielded enclosure. This dose field is still 
present in Step 9b, but a variable contribution from the scattered radiation in the emplacement 
drift turnouts is added to this stationary field as the transporter passes each turnout. 

800-00C-SS00-00100-000-00A 32 of 42 February 2004 
The dose rates at the turnout locations along the main access routes are assumed to be equal to 
the 2.5 mrem/hr dose-rate criterion (Section 4.1.6) over the entire 8-m width of the turnout 
opening (Section 4.1.2). This dose rate is assumed to linearly drop to negligible levels along the 
access main within 8 m on either side of the turnout opening (Assumption 4.2.5, not including 
the 2.5 mrem/hr contribution from any waste package being transported). This assumed doserate 
profile is illustrated in Figure 3. The average dose rate over the effective emplacement drift 
opening is calculated using Equation 5, where: 
i = 1, 2, 3 
E0, 1, 2, 3 = 0, 2.5, 2.5, and 0 mrem/hr, respectively 
D0, 1, 2, 3 = 0, 8, 16, and 24 m, respectively 
Note that in this dose-rate profile, all distance increments (Di – Di-1) are equal to 8 m. This value 
and the factor of 2 in the denominator can be taken out of the summation as a constant 
multiplicative factor. Therefore, the equation simplifies to EDRTO = {[(0 + 2.5) + (2.5 + 2.5) + 
(2.5 + 0)]/2} × (8/24), or 1.67 mrem/hr. 
Assuming a constant travel speed past each turnout location (Assumptions 4.2.9 and 4.2.10), the 
dose integration is mathematically equivalent to a constant dose rate of 1.67 mrem/hr over an 
effective distance of 24 m, and a negligible dose rate outside this distance (until reaching the 
next turnout area). 
This variable field is calculated as an average over the transporter route using Equation 4 as 
follows: 
EDRAv = (EDRTO × NED × DTO)/DED + {EDRMain × [DED – (NED × DTO)]}/DED, where EDRTO = 
1.67 mrem/hr (Calculated Value), NED = 45 (Assumption 4.2.6), DTO = 24 m (Assumption 4.2.5), 
EDRMain . 0 mrem/hr (Assumption 4.2.5), and DED = 1,964 m (Assumption 4.2.7). EDRAv = 
(1.67 × 45 × 24)/1964 + 0 = 0.92 mrem/hr. 
Adding the constant dose rate of 2.5 mrem/hr from the waste package inside the transporter 
results in an effective dose rate of 3.4 mrem/hr during Step 9b. The same variable fields will be 
experienced by the crew on the return trip through the emplacement area (Step 31a), but without 
the waste package inside the transporter. Therefore, the corresponding effective dose rate for 
Step 31a is 0.92 mrem/hr. 
The dose to workers transiting through the emplacement panel is simply the product of transit 
time and average dose rate. Thus, for Step 9a, the dose is 0.55 hr × 2.5 mrem/hr, or 1.4 mrem; 
for Step 9b, the dose is 0.30 hr × 3.4 mrem/hr, or 1.0 mrem; and for Step 31a, the dose is 0.30 hr 
× 0.92 mrem/hr, or 0.28 mrem. There would be no additional exposures to workers once they 
leave the emplacement area on the return trip (Step 31b). 
The dose rates to each crewmember are the same for most emplacement and retrieval steps. One 
exception to this rule occurs in Step 7 (Assumption 4.2.1), where two members of the 
four-person crew are assumed to be exposed to a field of 3.71 mrem/hr (Assumption 4.2.3), and 
the other two are exposed to a field of 2.5 mrem/hr (Assumption 4.2.4). This difference is 
accounted for in this calculation by dividing Step 7 into Step 7a (two workers outside the 

800-00C-SS00-00100-000-00A 33 of 42 February 2004 
locomotive cab) and Step 7b (two workers inside the locomotive cab). In addition, not all four 
crewmembers will be present for all operational steps, as indicated in Assumption 4.2.1. For 
example, only the crewmembers of the primary locomotive are involved in Steps 6 and 12. 
Steps 10, 12, and 29 are assumed to be conducted in the radiation field of the emplacement drift 
entrance (2.5 mrem/hr – Assumption 4.2.5). In Steps 10 and 12, the contribution from the loaded 
waste package transporter is added to this dose rate (2.5 mrem/hr – Assumption 4.2.4) for a total 
of 5 mrem/hr during these steps. In Step 29, the waste package transporter is empty and does not 
contribute to the dose rate, resulting in a dose rate of 2.5 mrem/hr at the turnout location. 
Combining the applicable assumptions from Section 4.2 with the exposure duration and dose 
rates calculated in this section provides sufficient inputs to permit the dose calculation for each 
worker in the emplacement and retrieval crew. The annual doses to each crewmember are 
calculated using Equation 1 and are presented in Table 7. 
The calculations, using design basis waste package dose rates, indicate that each of the two 
primary locomotive operators (W1/W2) would receive a maximum dose of 1,780 mrem/yr, 
which is slightly lower than the 1,890 mrem/yr to the two secondary locomotive operators 
(W3/W4). Using a scaling factor of 5:1 for design basis to average waste package dose rates 
under axial geometry exposure conditions (Assumption 4.2.15), the doses to the primary 
(W1/W2) and secondary (W3/W4) locomotive operators would be 360 and 380 mrem/yr, 
respectively. 
Exposure times, occupancy, and dose rates to workers during retrieval operations would be 
similar (but in reverse order of steps) to those calculated for emplacement operations. There 
would also be a reduction in the dose rates resulting from the radioactive decay of the waste 
package contents during the storage period. 
6.1.2 Collective Worker Doses – Emplacement or Retrieval Operations 
The annual collective dose to emplacement or retrieval workers is the sum of the total individual 
worker doses in each crew listed in Table 7, and is calculated using Equation 3. A single 
four-worker emplacement or retrieval crew would receive a maximum annual collective dose 
calculated as (1,780 + 1,780 + 1,890 + 1,890)/1000, or 7.3 person-rem/yr. This is doubled to 
15 person-rem/yr for the two shifts needed to accommodate a throughput of 600 waste packages 
per year (Assumption 4.2.11). Using a scaling factor of 5:1 for design basis to average waste 
package dose rates under axial geometry exposure conditions (Assumption 4.2.15), the collective 
doses, per crew and per annual throughput, would be 1.5 and 2.9 person-rem/yr, respectively. 

800-00C-SS00-00100-000-00A 34 of 42 February 2004 
Table 7. Design Basis Annual Doses to Individual Emplacement Crew Workers 
Step 
[A] 
W1/W2 
Exposure 
Duration (hr) 
[B] 
W3/W4 
Exposure 
Duration (hr) 
[C] 
W1/W2 
Dose Rate 
(mrem/hr) 
[D] 
W3/W4 
Dose Rate 
(mrem/hr) 
[E] 
Number of 
Operations 
(yr-1) 
[F] 
W1/W2 
Dose 
(mrem/yr) 
[G] 
W3/W4 
Dose 
(mrem/yr 
[H] 
1-6a N/A N/A N/A N/A 300 0 0 
6b 0.1 N/A 2.5 N/A 300 75 0 
7a,b 0.5 0.5 2.5 3.7 300 375 557 
8 0.1 0.1 2.5 2.5 300 75 75 
9a 0.55 0.55 2.5 2.5 300 412 412 
9b 0.30 0.30 3.4 3.4 300 313 313 
10 0 0 5.0 5.0 300 0 0 
11 0.5 0.5 2.5 2.5 300 375 375 
12 0 N/A 5.0 N/A 300 0 0 
13-28 N/A N/A N/A N/A 300 0 0 
29 0.1 0.1 2.5 2.5 300 75 75 
30 N/A N/A N/A N/A 300 0 0 
31a 0.30 0.30 0.92 0.92 300 84 84 
31b N/A N/A N/A N/A 300 0 0 
Total 2.5 2.4 N/A N/A 300 1,780 1,890 
Column [A]: Steps described in Section 4.1.1, with some refinements (a, b steps) explained in Section 6.1.1. 
Columns [B], [C]: From Table 3 (Number of Workers) and Table 4 (Exposure Duration), except Steps 9a, 9b, and 31a, which were 
calculated in Section 6.1.1. 
Columns [D], [E]: Assumption 4.2.3 (Step 7b), Assumption 4.2.4 (Steps 8, 9a, and 11), and Assumption 4.2.5 (Step 29); all others 
calculated in Section 6.1.1. 
Column [F]: Assumption 4.2.11. 
Column [G] = [B] x [D] x [F]. 
Column [H] = [C] x [E] x [F]. 
N/A: Not applicable to this step for reasons provided in Tables 3 and 4. 
Miscellaneous Totals: Only the time spent by workers in radiation fields is included and the number of operations is the same for 
all steps. Totals for Columns [G] and [H] are for Steps 1-31 and apply individually to each of the two workers (W1/W2 or W3/W4) 
represented in each column. 
6.2 MAINTENANCE WORKER DOSES 
Annual doses to individual emplacement and retrieval workers are calculated in Section 6.2.1. 
These doses are then summed in Section 6.2.2 to calculate the collective dose to this group of 
workers. 
6.2.1 Individual Worker Doses – Maintenance Operations 
The anticipated types of subsurface maintenance operations are described in Section 3.2. The 
required number of maintenance workers, and the duration and frequency of each maintenance 
operation, is described in Assumption 4.2.12, while dose rates at each maintenance location are 
listed in Assumption 4.2.13. 
As was the case with emplacement and retrieval operations, some workers will incur doses 
during their transit past filled emplacement drifts en route to the maintenance location. The 

800-00C-SS00-00100-000-00A 35 of 42 February 2004 
distances and mean dose rates from this transit are calculated in a manner similar as was 
conducted for emplacement and retrieval workers (Section 6.1.1). 
For each operation involving ventilation, electrical, or mechanical system maintenance, the most 
conservative dose estimate would result from transit through the entire length of Emplacement 
Panel 3, which requires going past a total of 45 turnouts on the east and west sides of the access 
route (Assumption 4.2.6). The average dose rates through this length of repository are the same 
as calculated in Section 6.1.1. However, since the support vehicle is assumed to operate at twice 
the speed of the waste package transporter (Assumptions 4.2.9 and 4.2.10), transit times and 
doses would be 50 percent lower. In Section 6.1.1, the product of transit time and average dose 
rates resulted in a dose of 0.28 mrem to each emplacement worker (Step 31a). The dose to each 
maintenance worker would be half this value in each direction, for a total round-trip dose of 0.28 
mrem per maintenance operation. 
Combining the applicable assumptions from Section 4.2 with the transit doses calculated in this 
section provides sufficient inputs to permit the dose calculation for each worker in a maintenance 
crew. The individual doses to each crewmember are calculated using Equation 2 and are 
presented in Table 8. 
Table 8. Design Basis Annual Doses to Individual Maintenance Crew Workers 
Maintenance 
Operation 
[A] 
Duration of 
Operation (hr) 
[B] 
Operation 
Dose Rate 
(mrem/hr) 
[C] 
Dose per 
Operation 
(mrem) 
[D] 
Transit Dose 
per Operation 
(mrem) 
[E] 
Number of 
Annual 
Operations 
[F] 
Annual 
Dose 
(mrem/yr) 
[G] 
Ventilation @ 
Door [1] 2 10 20 
Ventilation @ 
Main [2] 1.2 2.5 3 
23 
(sum) 0.28 10 233 
Electrical 3.5 10 35 0.28 12 423 
Mechanical (Rail) 8 2.5 20 0.28 5 101 
Ground Control 3.2 2.5 8 
Included as 
part of 
operation 
2 16 
Column [A]: Table 5, Column [A]. 
Column [B]: Table 5, Column [C]. 
Column [C]: Table 6, Column [B]. 
Column [D] = [B] x [C], except Ventilation Total: [D (sum)] = [D1] + [D2]. 
Column [E]: Calculated in Section 6.2.1 or part of operations per Assumption 4.2.12. 
Column [F]: Table 5, Column [D]. 
Column [G] = ([D]+ [E]) x [F], except Ventilation: [G] = ([D (sum)] + [E]) x [F]. 
N/A: Not applicable to Ventilation Total. 
Using a scaling factor of 5:1 for design basis to average waste package dose rates under axial 
geometry exposure conditions (Assumption 4.2.15), the doses to individual ventilation, 
electrical, mechanical, and ground control maintenance workers would be 47, 85, 20, and 3.2 
mrem/yr, respectively. 
6.2.2 Collective Worker Doses – Maintenance Operations 
The annual collective dose to maintenance workers is the sum of the individual worker doses in 
each crew and is calculated using Equation 3. Using the individual doses calculated in 

800-00C-SS00-00100-000-00A 36 of 42 February 2004 
Section 6.2.1 and crew sizes listed in Table 5 (Assumption 4.2.12), the annual collective dose for 
each maintenance operation is calculated and presented in Table 9. 
Table 9. Design Basis Annual Collective Doses for Subsurface Maintenance Operations 
Maintenance Operation 
[A] 
Crew Size 
[B] 
Individual Dose 
(mrem/yr) 
[C] 
Collective Dose 
(person-rem/yr) 
[D] 
Ventilation 3 233 0.70 
Electrical 1 423 0.42 
Mechanical 3 101 0.30 
Ground Control 1 16 0.016 
Total 8 N/A 1.4 
Column [A]: Table 5, Column [A]. 
Column [B]: Table 5, Column [B]. 
Column [C]: Table 8, Column [G]. 
Column [D] = [B] x [C]/1000. 
Using a scaling factor of 5:1 for design basis to average waste package dose rates under axial 
geometry exposure conditions (Assumption 4.2.15), the average collective doses to ventilation, 
electrical, mechanical, and ground control maintenance workers would be 0.14, 0.085, 0.061, and 
0.0032 person-rem/yr, respectively. 
7. RESULTS 
Individual and collective doses to subsurface repository workers are estimated using the 
methodology and equations described in Section 3, design parameters listed in Section 4.1, 
assumptions defined in Section 4.2, software described in Section 5, and calculations performed 
in Section 6. The parameters used in the dose calculations are supported by appropriate and 
conservative input data and assumptions. The calculated worker doses, summarized in Table 10, 
represent reasonable maximum and average results compared with the inputs used to derive 
them. The results are, therefore, suitable for the intended use. Uncertainties in the results are 
identified primarily by the use of input values related to design basis and average dose rates from 
the emplaced and transported waste packages. This uncertainty is evident in the range of results 
presented in Table 10. Additional uncertainties regarding the duration of operations, number of 
workers, and waste throughputs are not easily quantifiable, but the selected inputs are judged to 
be representative of conservative conditions. The impacts of some of these additional 
uncertainties and conservative input values are presented in Section 7.3. 
7.1 CONSIDERATION OF INTERNAL DOSES 
The Preliminary Consequence Analysis for License Application (BSC 2003f, Table II-15) 
indicates that total doses to maximally exposed subsurface workers from inhalation of airborne 
radionuclides would be less than 2 mrem/yr. This is well below the external doses listed in Table 
10 of this calculation. Therefore, the maximum annual TEDE for subsurface workers can be 
approximated by the total annual external dose to each worker reported in Sections 6.1.1 and 
6.2.1. 

800-00C-SS00-00100-000-00A 37 of 42 February 2004 
Table 10. Summary of Individual and Collective Doses to Subsurface Facility Workers 
Number of 
Workers/ 
Operation or 
Shift 
[A] 
Worker ID 
[B] 
Design Basis 
Individual 
Dose 
(mrem/yr) 
[C] 
Average 
Individual Dose 
(mrem/yr) 
[D] 
Shifts 
[E] 
Design Basis 
Collective 
Dose (personrem/
yr) 
[F] 
Average 
Collective 
Dose (personrem/
yr) 
[G] 
W1 
W2 1,780 360 
W3 
Four 
Emplacement/ 
Retrieval 
Workers per 
Shift (Eight per 
Operation) 
W4 1,890 380 
2 15 2.9 
W1 
W2 
Three 
Ventilation 
Maintenance 
Workers per 
Operation 
W3 
233 47 1 0.70 0.14 
One Electrical 
Maintenance 
Worker 
W1 423 85 1 0.42 0.085 
W1 
W2 
Three 
Mechanical 
Maintenance 
Workers per 
Operation 
W3 
101 20 1 0.30 0.061 
One Ground 
Control 
Maintenance 
Worker 
W1 16 3.2 1 0.016 0.0032 
Total 16 N/A N/A N/A 16 3.2 
Columns [A] and [B]: Assumptions 4.2.1 (Emplacement/Retrieval) and 4.2.12 (Maintenance). 
Columns [C] and [D]: Sections 6.1.1 (Emplacement/Retrieval) and 6.2.1 (Maintenance). 
Column [E]: Assumptions 4.2.11 (Emplacement/Retrieval) and 4.2.12 (Maintenance). 
Columns [F] and [G]: Sections 6.1.2 (Emplacement/Retrieval – Total for 2 Shifts) and 6.2.2 (Maintenance). 
NOTE: Total number of workers accounts for two shifts of four emplacement/retrieval workers. 
7.2 COMPARISON WITH REGULATORY LIMITS 
All the annual individual doses calculated in Section 6 are a factor of 2.6 or more times lower 
than the U.S. Nuclear Regulatory Commission regulatory limit of 5 rem/yr TEDE (Section 4.3). 
Since all the radiation fields used in this calculation affect the workers’ whole body, and do not 
preferentially irradiate the skin, lens of the eye, extremities, or specific organs, the TEDE limit is 
bounding. Therefore, all subsurface operations identified in this calculation comply with 
applicable regulations limiting occupational exposures. 
These doses have been calculated using radiation fields or design criteria applicable to design 
basis waste packages. This is a very conservative approach when operations involving large 
numbers of waste packages are considered. The result is higher exposures to personnel than 
would be incurred from the same number of average waste packages. Therefore, there is an 
adequate margin of safety in these calculations to provide assurance that the annual occupational 
dose limits would not be exceeded in any year from these operations. 

800-00C-SS00-00100-000-00A 38 of 42 February 2004 
7.3 COMPARISON WITH ALARA GOAL 
The individual doses to maintenance crew workers, including doses calculated using dose-rate 
criteria applicable to design basis waste packages, are all below the 500-mrem/yr ALARA goal 
(Section 4.4). Therefore, no additional ALARA considerations are required for such workers 
unless they are likely to be exposed to radiation from other maintenance activities not considered 
in this calculation. 
The 1,890 mrem/yr individual dose to emplacement and retrieval workers W3 and W4, 
calculated using dose-rate design criteria applicable to design basis waste packages, exceeds the 
ALARA goal specified in Section 4.4 by a factor of 3.8. However, assuming average rather than 
design basis waste packages as the basis for these calculations (Assumption 4.2.15) reduces the 
calculated doses to less than the 500-mrem/yr individual ALARA goal. 
In addition, the use of maximum travel distances and maximum throughput contributes to the 
conservatism in these calculations. For example, the dose contributions from the turnouts are 
highly dependent on the location of the active emplacement area in each panel. A projected 
maximum throughput of 526 waste packages per year in 2022 and 2023 (Cloud 2003, Table 4) 
would result in annual doses to emplacement workers approximately 12 percent lower than doses 
calculated using a throughput of 600 waste packages per year (Assumption 4.2.11). The annual 
waste package throughput (and the calculated collective doses) would be lower in other years. In 
addition, fewer filled drifts early in the emplacement phase would result in lower doses to 
maintenance workers since annual doses are assumed to peak towards the end of the 
emplacement operations, when most drifts are full. 
Finally, if only a two-person crew (rather than a four-person crew, per Assumption 4.2.1) 
performs subsurface emplacement and retrieval operations (one operator per locomotive), this 
would reduce the collective dose to emplacement and retrieval workers by almost 50 percent. 
While a formal ALARA evaluation for the subsurface operations considered in this calculation is 
outside the scope of this calculation, some of the considerations presented here may be applied as 
part of such an evaluation. 
8. REFERENCES 
8.1 DOCUMENTS CITED 
BSC (Bechtel SAIC Company) 2003a. Underground Layout Configuration. 800-P0C-MGR0- 
00100-000-00E. Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20031002.0007. 
[DIRS 165572] 
BSC 2003b. Emplacement and Retrieval System Description Document. 800-3YD-HE00- 
00100-000-000. Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20030930.0009. 
[DIRS 165574] 
BSC 2003c. Ventilation Network Model Calculation. 800-M0C-VU00-00100-000-00A. 
Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20030714.0001. [DIRS 164054] 

800-00C-SS00-00100-000-00A 39 of 42 February 2004 
BSC 2003d. Dose Rate Calculation for Emplacement Drift Turnout Configurations. 800-00CWIS0-
00200-000-00A. Las Vegas, Nevada: Bechtel SAIC Company. 
ACC: ENG.20030904.0005. [DIRS 165078] 
BSC 2003e. Geological Repository Operations Area North Portal – Site Plan. 100-P00-MGR0- 
00101-000-00A. Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20030820.0012. 
[DIRS 164658] 
BSC 2003f. Preliminary Consequence Analysis for License Application. CAL-WHS-RL-000002 
REV 00A. Las Vegas, Nevada: Bechtel SAIC Company. ACC: DOC.20030929.0015. [DIRS 
165091] 
BSC 2003g. Dose Rate Calculation for 21-PWR Waste Package. 000-00C-DSU0-01800-000- 
00A. Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20030903.0003. 
[DIRS 164533] 
BSC 2004. Waste Package Transporter Shielding Design Calculation. 000-00C-HE00-00100- 
000-00A. Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20040202.0021. [DIRS 
167113] 
Cloud, J.D. 2003. Waste Package Per Year Estimate for Planning Purposes. Interoffice 
Memorandum from J.D. Cloud (BSC) to M.P. Board, P. McDaniel, T.W. Mulkey, and 
S.L. Sethi, April 30, 2003, 0429037098, with attachment. ACC: MOL.20030527.0392. 
[DIRS 163991] 
DOE (U.S. Department of Energy) 2003. Quality Assurance Requirements and Description. 
DOE/RW-0333P, Rev. 13. Washington, D.C.: U.S. Department of Energy, Office of Civilian 
Radioactive Waste Management. ACC: DOC.20030422.0003. [DIRS 162903] 
Edwards, T.A. and Yuan, Y. 2003. Recommended Surface Contamination Levels for Waste 
Packages Prior to Placement in the Repository. 000-30R-OSS0-00100-000-000. Las Vegas, 
Nevada: Bechtel SAIC Company. ACC: ENG.20030903.0001. [DIRS 164177] 
Minwalla, H.J. 2003. Project Design Criteria Document. 000-3DR-MGR0-00100-000-001. 
Las Vegas, Nevada: Bechtel SAIC Company. ACC: ENG.20030402.0001. [DIRS 167101] 
8.2 CODES, STANDARDS, REGULATIONS, AND PROCEDURES 
10 CFR 20.1201. Energy: Standards for Protection Against Radiation, Occupational Dose 
Limits for Adults. Readily available. [DIRS 161817] 
AP-3.12Q, Rev. 2, ICN 1. Design Calculations and Analyses. Washington, D.C.: U.S. 
Department of Energy, Office of Civilian Radioactive Waste Management. 
ACC: DOC.20030827.0013. [DIRS 165022] 
AP-SI.1Q, Rev. 5, ICN 2. Software Management. Washington, D.C.: U.S. Department of 
Energy, Office of Civilian Radioactive Waste Management. ACC: DOC.20030902.0003. 
[DIRS 165023] 

800-00C-SS00-00100-000-00A 40 of 42 February 2004 
INTENTIONALLY LEFT BLANK 

800-00C-SS00-00100-000-00A 41 of 42 February 2004 
ATTACHMENT I 
DOSE-RATE REDUCTION FACTORS FOR THE AVERAGE SPENT NUCLEAR FUEL 
This attachment presents an estimation of dose-rate reduction factors between a waste package 
loaded with the design basis pressurized water reactor (PWR) spent nuclear fuel (SNF) and one 
with the average PWR SNF, and between a waste package loaded with the bounding PWR SNF 
and one with the average PWR SNF. The dose rates outside a 21-PWR waste package are 
obtained from the Dose Rate Calculation for 21-PWR Waste Package (BSC 2003g). The nuclear 
characteristics of the three spent fuel types are described in BSC 2003e (Section 5.1.4). The 
reduction factors are derived separately for the radial, top, and bottom directions of a 21-PWR 
waste package. Table I-1 summarizes the dose rates and reduction factors for a 21-PWR waste 
package separately loaded with one of the three spent fuel types. 
Table I-1. Dose Rates and Reduction Factors for a 21-Pressurized Water Reactor Waste Package 
Radial Direction 
Location Dose Rate (rem/hr)a Reduction Factor 
Design Basis SNF 
[A] 
Average SNF 
[B] 
Bounding SNF 
[C] 
Bounding/ 
Average 
[D] 
Design Basis/ 
Average 
[E] 
Surface [1] 5.83E+02 1.93E+02 1.38E+03 7.15 3.02 
1-meter [2] 2.23E+02 7.26E+01 5.22E+02 7.19 3.07 
2-meter [3] 1.38E+02 4.42E+01 3.23E+02 7.31 3.12 
Average [4] - - - 7.22 3.07 
Top Direction 
Location Dose Rate (rem/hr)b Reduction Factor 
Design Basis SNF 
[A] 
Average SNF 
[B] 
Bounding SNF 
[C] 
Bounding/ 
Average 
[D] 
Design Basis/ 
Average 
[E] 
Surface [1] 4.06E+02 6.02E+01 8.60E+02 14.29 6.74 
1-meter [2] 1.16E+02 1.87E+01 2.48E+02 13.26 6.20 
2-meter [3] 5.87E+01 1.03E+01 1.26E+02 12.23 5.70 
Average [4] - - - 13.26 6.22 
Bottom Direction 
Location Dose Rate (rem/hr)b Reduction Factor 
Design Basis SNF 
[A] 
Average SNF 
[B] 
Bounding SNF 
[C] 
Bounding/ 
Average 
[D] 
Design Basis/ 
Average 
[E] 
Surface [1] 1.30E+03 2.21E+02 2.80E+03 12.67 5.88 
1-meter [2] 3.69E+02 6.47E+01 8.02E+02 12.40 5.70 
2-meter [3] 1.70E+02 3.08E+01 3.70E+02 12.01 5.52 
Average [4] - - - 12.36 5.70 
Column [D] = [C]/[B], except [D4] = Average ([D1]:[D3]) 
Column [E] = [A]/[B], except [E4] = Average ([E1]:[E3]) 
aBSC 2003g, Tables 6.1-7, 6.1-8, 6.1-9, 6.2-2, 6.2-3, 6.2-4, 6.3-2, 6.3-3, and 6.3-4. The dose rates of Segment 6 in the 
tables were chosen. 
bBSC 2003g, Tables 6.1-10, 6.2-5, and 6.3-5 

800-00C-SS00-00100-000-00A 42 of 42 February 2004 
INTENTIONALLY LEFT BLANK