OPERATING EXPERIENCE WEEKLY SUMMARY 93-38
September 17 through 23, 1993
The purpose of the Office of Nuclear Safety (NS) Operating Experience (OE) Weekly
Summary is to enhance safety throughout the Department of Energy (DOE) complex
by promoting feedback of operating experience and encouraging the exchange of
information among DOE nuclear facilities. The OE Weekly Summary is distributed
for information only. No specific actions or responses are required solely as a
result of this document.
Readers are cautioned that review of the OE Weekly Summary should not be relied
upon as a substitute for a thorough review of the interim and final Occurrence
Reports.
The following events were reviewed during the week of September 17 through 23, 1993.
ITEM PAGE
1. FOREIGN MATERIAL FOUND IN REACTOR VESSEL 2
2. VIOLATION OF TECHNICAL STANDARD AT CPP-603 FACILITY 3
3. SWITCHES FOUND IN IMPROPER POSITION 4
4. CRITICALITY CONTROL VIOLATION AT BABCOCK AND WILCOX
FACILITY 5
5. INCORRECT USE OF CHAIN AND HASP LOCKOUT 6
6. INADVERTENT BREAKER OPERATION CAUSES POWER OUTAGE
TO MULTIPLE FACILITIES 7
7. EMPLOYEE DRIVES METAL FENCE POST INTO 480-VOLT BURIED
CABLE 8
8. INTENTIONAL DEGRADATION OF NUCLEAR INCIDENT MONITOR
ALARM 9
9. WORKER BURNED FROM ENERGIZED WIRE 10
ADDITIONAL INFORMATION RELATED TO FOLLOWUP ACTIVITIES
1. IDAHO TEST REACTOR AREA HOT CELL RADIATION STREAMING
EVENT CORRECTIVE ACTIONS 11
1. FOREIGN MATERIAL FOUND IN REACTOR VESSEL
On September 15, 1993, personnel at the Advanced Test Reactor in Idaho submitted an
off-normal occurrence report after discovering foreign material in the reactor vessel for
the second time in less than a week. On September 8, facility personnel found a
damaged C-cell battery in the vessel and then found crushed flashlight parts on
September 13. All foreign material was located outside the core region and there was
no fuel damage.
After removing the C-cell battery on September 8, facility personnel performed a thorough
examination of the vessel and found no other debris. Although engineers could not
determine how the battery got into the vessel, facility management concluded it was
unlikely that there was other debris in the vessel. Site personnel reported that a certain
amount of foreign material in the vessel is analyzed for and determined to be acceptable
in the facility Safety Analysis Report. Facility personnel closed up the vessel and
conducted operational tests at approximately four megawatts for 20 minutes. The vessel
was then reopened, new flux monitors installed, another internal inspection performed,
and a similar operational test conducted. Workers found the crushed flashlight parts
during a subsequent vessel inspection on September 13. (ORPS Report ID--EGG-ATR-1993-
0032)
Management personnel placed a hold on reactor operations and initiated efforts to locate
the remaining flashlight parts and to determine the entry point of the flashlight into the
primary coolant system. After conducting various activities designed to retrieve the
remaining parts and finding some small pieces, facility personnel located a white plastic
ring floating beneath a screen on the inlet side of the reactor. Site personnel reported
that the location of the ring indicated the flashlight most likely entered the primary coolant
system at a point other than the reactor vessel. Facility personnel reviewed work
performed during the previous outage and determined that the flashlight probably entered
the system through the outlet piping of a primary coolant emergency pump during
maintenance.
Facility personnel reviewed the Safety Analysis Report and determined that the remaining
amount of material in the vessel, assuming an entire flashlight entered the system, would
not adversely impact safe operation of the reactor. However, personnel continued efforts
to remove additional foreign material. Site personnel planned to conduct an evaluation
of foreign material exclusion (FME) practices and procedures in place when the flashlight
entered the system. Preliminary indications are that FME controls may not be as formal
during work on systems connected to the reactor vessel as they are during work around
the vessel when it is open.
This event underscores the need for effective FME procedures and controls to protect
critical equipment and systems at DOE facilities from degradation caused by foreign
material. Facility personnel should be aware of the potential for foreign material migration
to critical equipment from systems and equipment that, without a thorough technical
evaluation, may not seem to present such a potential. DOE 4330.4A, Maintenance
Management Program, Section 8.3.3, states that maintenance supervisors should
routinely monitor work in progress and check for good work practices, including "open
system and component protection."
2. VIOLATION OF TECHNICAL STANDARD AT CPP-603 FACILITY
On September 19, 1993, operations personnel at the Idaho National Engineering
Laboratory CPP-603 Irradiated Fissile Materials Storage facility discovered two fuel-laden
carbon-steel hangers, or yokes, improperly spaced and in violation of the technical
standard designed to provide criticality safety. Although the technical standard was
violated, there was no criticality concern because the fuel was not highly reactive and the
distance between the fuel buckets was greater than the edge-to-edge requirement that
prevents neutron interaction in water. (ORPS Reports ID--WINC-FUELRCSTR-1993-0009)
Building CPP-603 is a facility used for underwater storage of nuclear fuel in three
underwater storage basins (north, south, and middle) and above-ground dry storage.
Irradiated fuel is suspended from a monorail system by single elements or in buckets
which can contain several small elements. The elements or buckets are attached to
hooks, generally made of stainless steel, that are welded to a steel yoke (carbon or
stainless) hanging from the monorail. The yokes have upper and lower bumpers to
ensure that correct spacing and adequate separation are maintained for criticality safety,
and they are classified as an engineering safety feature.
The facility Technical Standard states that the north and middle storage basins will be
inspected quarterly to ensure that like yokes are segregated into rows and that unlike
yokes in the same row are separated by an empty yoke and bucket to provide blank
spacing. The facility safety analysis report requires a water space of eight inches (edge-
to-edge) between fissile materials to provide near neutron isolation from neutron
interaction in water. This spacing is provided by the yoke-bumper design for like yokes,
which are dimensionally identical. Unlike yokes have different spacing from the trolley
to the lower bumpers, and the bumpers will be mismatched. Mismatched bumpers do
not prevent adjacent yokes from approaching closer than eight inches. Facility personnel
avoid this problem by placing only like yokes in a row. However, if unlike yokes are in
the same row, workers separate them by placing an empty yoke and bucket between
them, thus ensuring neutronic isolation.
Workers recently moved the subject yokes during performance of Special Procedure
#220-93 "SNAP Fuel Re-spacing, Rerigging, and Re-storage." Two operators visually
verified the yokes as like yokes by looking through approximately 22 feet of water to
determine if the bumpers were five feet apart and of equal height from the monorail.
During the bi-monthly inspection, facility personnel actually measured the height of the
yokes and discovered a six inch difference between them, which verified the yokes to be
unlike. Upon discovering this, the workers reverified the measurements and notified
management. Facility personnel reported that the special procedure that had been used
did not provide objective criteria for inspecting the bumpers and did not require use of
measurement devices.
In this event, the two yokes were separated by an empty yoke without the required
bucket. Facility personnel reported that the edge-to-edge distance was approximately 30
inches, well above the eight-inch edge-to-edge requirement; and the fuel in the buckets
was not highly reactive. The criticality safety criteria section of the Plant Safety
Document (the Safety Analysis Report) for building CPP-603 established criticality
prevention measures and described two conditions that could lead to a criticality event.
The first was a failure to properly isolate highly reactive fuel handling units (FHU)
suspended from the monorail system. The second was the release of an FHU from its
intended monorail storage position.
NS reported in OE Weekly Summary 92-22 about the loss of these barriers at CPP-603.
On September 18, 1992, an engineering team determined that 25 highly reactive FHUs
were in adjacent positions without proper spacing. This was significant because a
criticality event could result if these elements dropped to the basin floor and achieved an
unfavorable geometry, thus violating the first condition described in the Plant Safety
Document. Prior to that event on March 16, 1992, a corrosion engineer discovered that
one of the FHU yokes failed because of corrosion. This yoke was not used for storage
of nuclear fuel elements at the time of the failure. Facility personnel subsequently
declared that the corroding carbon steel yokes resulted in an unreviewed safety question,
constituting an occurrence of the second condition described in the Plant Safety
Document (ORPS Report ID--WINC-ICPP-1992-0024). Facility personnel developed Special
Procedure #220-93 because of these criticality concerns.
Corrosion of fuel storage equipment continues to be a problem at CPP-603. NS reported
in OE Weekly Summary 93-37 about recent fuel corrosion problems at the facility. On
September 13, 1993, personnel were rigging a fuel handling bucket containing a canister
of System for Nuclear Auxiliary Power fuel in preparation for re-storage when the canister
broke apart because of corrosion. Approximately 14 inches of the top section of the
canister and three fragments of highly reactive fuel pins separated and fell onto the safety
catch pan located under the storage bucket. (ORPS Report ID--WINC-FUELRCSTR-1993-0007)
3. SWITCHES FOUND IN IMPROPER POSITION
On September 14, 1993, operations personnel at Rocky Flats Building 779 discovered
the Hand-Off-Auto-off (HOA) switches for standby exhaust fans F401A and F402A in an
improper position. These fans are part of the glovebox and hood exhaust system. The
Stationary Operating Engineer (SOE) identified the improper switch configuration prior to
performance of the monthly fan rotation surveillance procedure. Earlier in the day, the
facility maintenance electricians and systems engineer performed a Post-Maintenance
Test on these fans and the test procedure required the HOA switch to be placed in the
OFF position and verification that the backdraft dampers were open. Facility personnel
completed this task and the SOE returned the switch to the AUTO position. The SOE
verified this action by radio contact to operators in the utilities control room.
During the next shift, control room operators preparing to perform the surveillance test
noticed a motor stop light for the fans, indicating that the switches were in the OFF
position. Both the utilities manager and the SOE confirmed that the HOA switches for
both fans were in the OFF position. The utilities manager returned the HOA switches to
the AUTO position and notified the shift manager of the event. Facility personnel
subsequently successfully completed the surveillance of the fans.
Facility personnel are investigating the event for identification of corrective actions and
lessons learned. They attributed the direct cause of this occurrence to inattention to
detail (i.e., personnel failing to maintain the HOA switches in the proper position). DOE
and internal security were notified of this event. (ORPS Report RFO--EGGR-ANALYTOPS-1993-
0139)
On August 16, 1993, a similar event occurred at the facility during the monthly fan
rotation surveillance. In this incident, the Building 559/779 utilities manager discovered
the HOA switch for Building 779 exhaust fans F401A/B was not in the AUTO position as
required. The improper switch position resulted in no standby fan capability. The SOEs
attempted the monthly fan rotation and exhaust fan F401B did not activate as required.
The utilities manager proceeded to check the HOA switch and discovered the improper
position. On August 13, 1993, facility personnel performed a loop calibration on this fan.
However, they reported that all information (i.e., visual confirmation and work package
signatures) indicated the switch was placed in the AUTO position as required. There was
no activity on this system between the loop calibration and the discovery. Facility
personnel are still investigating the cause of how the switch was placed in the wrong
position. (ORPS Report RFO--EGGR-ANALYTOPS-1993-0118)
These events emphasize the importance of maintaining system configuration by
performing lineups after maintenance and before returning systems and components to
service, including independent verification of procedure sign-offs as applicable. Switches
or valves left out of their normal positions should be tagged or otherwise marked to avoid
operational problems resulting from operators assuming that they are in the normal
position. Information on other equipment mispositioning events can be found in Institute
for Nuclear Power Operations (INPO) Significant Event Report 6-92, "Valve Mispositioning
Events," INPO Significant Operating Experience Report 85-2, "Valve Mispositioning
Events Involving Human Error," and Nuclear Regulatory Commission Information Notice
87-25, "Human Error - Wrong Unit, Train, or Component."
4. CRITICALITY CONTROL VIOLATION AT BABCOCK AND WILCOX FACILITY
On September 16, 1993, personnel at the Babcock and Wilcox (B&W) Uranium Fuel
Fabrication facility in Lynchburg, Virginia, discovered a violation of an administrative
criticality control and reported the event in accordance with Nuclear Regulatory
Commission (NRC) Bulletin 91-01. They discovered 436 grams of uranium-235 in a room
where the maximum mass limit was 350 grams. Workers were chemically separating
organic, aqueous, and carbon tetrachloride mixed wastes containing highly enriched
uranium oxycarbide when the event occurred. When solutions of uranium-235 are taken
into the processing laboratory, facility personnel are required to log the mass content to
ensure that the total does not exceed 350 grams. In this event, workers brought a drum
into the work area that contained two different solutions with separate mass values for
each solution. The records accompanying the drum indicated the proper values. When
they recorded the mass value in the laboratory log, only one of the two values was
entered. When the accounting discrepancy was discovered later in the day, workers
immediately removed the material from the area.
Facility personnel reported that, although the mass amount exceeded administrative
limits, the quantity was below the actual critical mass amount of 820 grams. In addition,
the second criticality contingency of a minimum required spacing between containers was
never violated. Facility personnel are investigating the event for identification of
corrective actions and lessons learned. NRC Bulletin 91-01, "Reporting Loss of Criticality
Safety Controls," requires all fuel cycle and uranium fuel research and development
licensees to report violations of criticality contingencies. (NRC Event Notification Number 26099)
For DOE facility contractors, DOE 5480.24, "Nuclear Criticality Safety," provides direction
on establishing nuclear criticality safety program requirements. This order establishes a
double contingency principle to prevent a criticality accident and provides necessary
elements for criticality safety programs. Also, the order invokes several American Nuclear
Society Standards for basic elements and control parameters of programs for nuclear
criticality safety.
5. INCORRECT USE OF CHAIN AND HASP LOCKOUT
On September 14, 1993, a locked-out fan pulley at the Savannah River K-Reactor began
to rotate slowly while maintenance personnel were replacing the belts on the fan. The
fan rotation was caused by differential pressure from an operating fan sharing the same
suction and exhaust header, a phenomena referred to as windmilling. The inability of the
lockout to prevent the fan pulley from rotating raised concerns regarding the adequacy
of the lockout and the potential for personnel injuries when operating equipment locked
out in a similar manner. There were no personnel injuries or equipment damage caused
by the event.
The lockout, installed to allow replacement of the fan belts, isolated electrical power to
the motor and included a chain wrapped through the spokes of the pulley and around a
bearing pedestal and locked with a hasp to prevent rotation caused by windmilling. After
mechanics removed about half of the belts from the fan, the hasp and chain came loose
and the fan pulley began to rotate slowly. Investigators determined that the hasp,
normally used to prevent personnel from inadvertently operating equipment, not as a
load-bearing blocking device, was not capable of withstanding the stress caused by the
windmilling and failed. Initially, the friction from the belts connected to the motor was
sufficient to prevent windmilling. However, as the mechanics removed the fan belts,
friction was reduced until the windmilling force was sufficient to cause rotation of the
pulley and failure of the hasp. Facility personnel also noted that the suction damper for
the fan, which helps minimize the windmilling effect when closed, was not included in the
lockout.
Facility personnel stopped all work on the fan and other equipment using similar lockouts
while the event was investigated. Investigators found that one part of the Reactor
Division safety manual specified using a chain and lock while another part of the manual
stated that a timber (such as a 4X4) should be used as a blocking device. Workers had
not been using timbers because they caused difficulties in removing the belts and
because of the conflicting safety manual requirements. Facility personnel are developing
a locking device that will allow unrestricted removal of the fan belts and at the same time
provide enough strength to absorb the windmilling forces. (ORPS Report SR--WSRC-REACK-
1993-0156)
This event underscores the need for personnel at DOE facilities to ensure that devices
used to restrain equipment from operating are designed to withstand the resulting
stresses. Failure to do so, especially when personnel are working near the restrained
equipment, could result in serious personnel injury or damage to nuclear safety-related
equipment. In this incident, the hasp was used to restrain the fan from rotating and failed
because it was not designed to withstand the resulting stresses. Also, site safety
manuals should specifically address use of lockouts designed to physically prevent
equipment movement, as opposed to preventing human operation.
6. INADVERTENT BREAKER OPERATION CAUSES POWER OUTAGE TO MULTIPLE
FACILITIES
On September 20, 1993, an operator performing preventive maintenance at a substation
at the Savannah River Site opened the wrong circuit breaker, causing a loss of power to
multiple facilities, including the Effluent Treatment Facility (ETF), the H-Area Tank Farm,
and administrative facilities. The ETF processes slightly radioactive water for release to
the environment, and the H-Area Tank Farm is a high-level radioactive liquid waste
storage facility. Backup diesel generators at both facilities started and operated as
designed. There was no adverse impact to personnel safety or the environment as a
result of the event. (ORPS Reports SR--WSRC-POD-1993-0032, SR--WSRC-ETF-1993-0007, SR--WSRC-
HTANK-1993-0066)
Facility personnel indicated the power outages were caused by personnel error when an
electrical equipment operator working in a switchyard inadvertently opened a 13.8kv
feeder breaker. The operator set his work package down behind him and turned around
to operate a permissive switch to allow opening of a cubicle for a just-opened breaker.
However, he turned the switch on the breaker next to the correct one instead. Site
personnel reported the breakers were adequately labeled and the operator had an
approved work package and procedure plus 15 years experience at the site.
The power outages lasted for approximately one hour. All power was lost to the ETF and
the Old Hill Tank Farm (part of the H-Area Tank Farm). The ETF was operating under
normal conditions when power was lost and operators verified that emergency generators
were operating and ensured the plant was in a safe shutdown condition. The Old Hill
Tank Farm evaporator was not operating at the time. However, power was lost to
storage tank ventilation purge fans. Operators verified operation of emergency
generators and restarted the fans.
Although there were no serious consequences from this event, it underscores the need
for extra precautions and awareness when operating equipment that, if improperly
operated, could adversely impact operations at multiple facilities. NS described events
caused by personnel errors in previous OE Weekly Summaries and referred to a
technique referred to as self-checking. Self-checking is a risk management tool designed
to reduce potential for human error by helping facility personnel focus attention on details
of the task at hand and to identify and avoid potential human errors before they occur.
This technique is widely used in the commercial nuclear industry, and the Institute for
Nuclear Power Operations (INPO) has issued a number of documents describing the
elements of effective human error reduction programs at commercial nuclear utilities.
Also, many commercial nuclear utilities incorporate two-man switches at high voltages to
prevent errors and protect personnel.
7. EMPLOYEE DRIVES METAL FENCE POST INTO 480-VOLT BURIED CABLE
On September 16, 1993, personnel at the Idaho Chemical Processing Plant discovered
that the overhead crane in the Fuel Process Restoration (FPR) facility would not function
because of a loss of power. Personnel investigated the event and discovered that a
fence post had severed the 480-volt buried cable supplying temporary power to the
crane. On August 30, 1993, workers installed four fence posts in the ground as anchors
for a trailer and a housing that supported a soil sample drilling project. After cutting the
cable, the workers did not immediately notice the loss of power because the FPR crane
was not in use. Facility personnel discovered the condition when they attempted to
switch the power feed to the crane from temporary to permanent.
As part of the soil sample drilling project, facility personnel obtained an excavation permit
that detailed the locations of telephone cables, imbedded electrical cable, and
underground piping. The temporary buried cable for the FPR crane was documented on
the permit. The workers installing the fence posts apparently did not properly check the
permit prior to driving the posts. In addition, the cable was buried only two feet deep and
was not identified by marker flags (ORPS Report ID--MKF-MKNE-1993-0001).
A similar event occurred on September 15, 1993, at the Savannah River Effluent
Treatment Facility when a worker encountered an underground pipe while drilling for a
soil sample. The pipe was a low-level radioactive waste-water transfer line made of high-
density polyethylene. The jacketed portion of the pipe was damaged, but facility
personnel reported that no waste water was released to the public. Facility personnel
conducted a critique and determined that the causes included lack of preparation of an
evacuation permit, relocation of the drilling stakes approximately 20 feet south of their
originally surveyed location without proper followup, and lack of established work control
procedures.
In December 1992, workers surveyed and staked the area where the drilling was
planned. Six months later they conducted a ground penetrating radar survey of the area
to identify underground interferences. In July 1993, workers moved to a new drilling
location in order to clear the overhead power line right-of-way. This new location was
outside the originally surveyed boundary. The workers failed to perform either a ground-
penetrating radar or a coordinate survey at the new stake locations (SR--WSRC-ETF-1993-
0005).
NS discussed problems with damage to underground cable, piping, conduits, and
structures during excavations in previous OE Weekly Summaries. Several events in this
category could have resulted in serious personnel injury. On September 14, 1992, an
underground natural gas pipeline ruptured when it was struck by a back hoe during an
electrical utility relocation project at the Lawrence Berkeley Laboratory. Facility personnel
previously surveyed the area for underground obstructions in accordance with
procedures, but a change in the job order altered locations. The workers failed to survey
the new area and subsequently punctured an underground gas line with a back hoe. No
one was injured as a result of this event (ORPS Report SAN--LBL-OPERATIONS-1992-0007). A
follow-up investigation determined that facility drawings were not adequately updated to
show the location of the gas line when it was installed in 1989. There was no tape or
trace wire installed marking the location of the line. In addition, facility personnel reported
that the pipeline was buried closer to the surface than required by code (OE Weekly Summary
92-21).
A similar event occurred on October 10, 1991, when personnel at the Los Alamos
National Laboratory ruptured an underground natural gas line with a back hoe. They
obtained an approved evacuation permit and all utilities were properly marked for
location. However, the depth of the piping could not be properly measured with
instruments available and facility personnel failed to follow procedures that required
manual exploration prior to machine excavation. The piping was buried only 10 to 12
inches below the surface (ORPS Final Report ALO-LA-LANL-PHYSTECH-1991-1009). Another near
miss occurred on September 20, 1991, at the Grand Junction Operations facility when
a worker severed a 13,000 volt underground power cable located one foot below the
surface while removing mill tailings at the Uranium Mill Tailings Remedial Action Site.
Facility drawings incorrectly showed the cable as being buried four feet deep and
encased in concrete (ORPS Report ID--GEO-GJO-1991-1019).
These events demonstrate the necessity to thoroughly investigate the possibility of
underground obstructions prior to commencing excavations. Review of plant facility
drawings may not be adequate for locating potential underground cables, conduits, tanks,
or piping. In addition, facility record drawings may lack information necessary to assure
correct marking of buried utilities. Excavations around utilities should be dug using hand
tools. Security and telecommunication personnel should be consulted prior to digging to
assist in identification of buried components. Facility procedures controlling excavations
should provide detailed steps for locating underground obstructions. Likewise,
underground cables, including temporary installations, should be identified with locator
flags. At commercial nuclear power plants, personnel often use cable locating equipment
such as Dynatel manufactured by the 3-M Corporation or ground-penetrating radar to
locate cables prior to excavation.
8. INTENTIONAL DEGRADATION OF NUCLEAR INCIDENT MONITOR ALARM
On September 20, 1993, a supervisor performing daily checks of a Nuclear Incident
Monitor (NIM) test panel at the Savannah River Reactor Materials facility discovered that
an alarm on the panel had been intentionally muffled. The alarm, which had been taped
over, functions to warn operators if electronic circuitry detects a functional problem with
any of the building NIMs. There was minimal impact on the ability to warn site personnel
of an actual nuclear incident because (1) the taped alarm was not needed for that
purpose and (2) a redundant NIM for each monitored area is available in the event a
problem with one NIM is undetected because of the taped alarm.
Investigators determined that the alarm was taped over sometime between Thursday
morning (16 September) and Monday morning (20 September) when it was discovered.
Facility personnel have not determined who taped over the alarm or why, but suspect the
alarm may have sounded during an electrical storm and 40-minute power outage on
Friday evening. Workers removed the tape from the alarm and retested it for proper
audio response. Planned corrective actions include revision of the daily NIM check
procedure to specifically require inspection of the alarm for obstructions and
reemphasizing to facility personnel the importance of not tampering with alarms and
warning systems. (ORPS Report SR--WSRC-RMAT-1993-0017)
In OE Weekly Summary 92-21, NS reported other events involving intentional disabling
and misuse of alarms and warning systems at DOE facilities. On September 13, 1992,
Rocky Flats personnel discovered that some workers changed the radio frequency on a
Life Safety/Disaster Warning (LS/DW) system radio transmitter and used the headsets
to listen to music (ORPS Report RFO--EGGR-PUFAB-1992-0254). On January 7 and 20, 1992,
personnel discovered a pair of orange visitor coveralls taped around the inner cone of a
LS/DW speaker and T-shirts stuffed into another speaker at Rocky Flats (ORPS Report RFO--
EGGR-PUFAB-1992-0008,0013). On November 27, 1991, Argonne National Laboratory - West
personnel discovered that the volume on a Life Safety System speaker had been turned
so low as to effectively turn it off. Investigators determined that the root cause of the
event was the failure of management to effectively communicate the hazards associated
with adjusting the volume on speakers intended to support life safety functions. (ORPS
Report CH-AA-ANLW-FCF-1991-1006)
These events illustrate that all personnel at DOE facilities may not fully understand the
safety significance of alarms and warning systems designed to alert personnel to
emergency situations, and the potential hazards associated with tampering and misuse
of these systems. According to one of the referenced ORPS reports, a Final Safety
Analysis Report describes the LS/DW as the most critical alarm system at Rocky Flats.
Facility management should ensure that the safety significance of tampering and misuse
of these systems is effectively communicated to site personnel.
9. WORKER BURNED FROM ENERGIZED WIRE
On September 21, 1993, a worker in Building 710 at the Nevada Test Site received minor
burns while she was working in an energized junction box. The employee was adding
ground wires to an air conditioning circuit and pulled a wire with a pair of pliers. The
pliers cut through the insulation and contacted the side of a junction box. A short circuit
resulted and caused minor flash burns on the worker's hands. She was transported to
a medical facility, treated, and released. Facility personnel are investigating the event
for identification of cause, corrective actions, and lessons learned. (ORPS Report NVOO--
REEC-OMD6-1993-0003)
A number of personnel injuries and near misses from electric shock have been reported
by other DOE facilities. A recent near miss occurred on August 18, 1993, at the Los
Alamos National Laboratory Physics Complex when an electrician came in contact with
a live 440-volt ac bus and ground with a wrench causing a substation breaker to trip.
This resulted in a loss of power to a portion of the facility. Although no personnel injuries
or equipment damage resulted from this event, there was a potential for serious injury or
fatality (ORPS Report ALO-LA-LANL-PHYSCOMPLX-1993-0006). On May 22, 1992, a technician
at the Lawrence Livermore National Laboratory received an electrical shock while
connecting a cable between equipment and a high-voltage power supply that had not
been de-energized (ORPS Report SAN--LLNL-LNL-1992-0055). In another event on September
9, 1992, two electricians at Rocky Flats Building 707 received flash burns to their hands
when an allen wrench used by one to tighten a ground lead slipped and made contact
with an energized 480-volt bus bar. The post incident investigation determined that the
electricians were not working in compliance with electrical safety requirements contained
in the facility Health and Safety Practice Manual (ORPS Report RFO--EGGR-PUFAB-1992-0248).
On November 5, 1990, an electrician at the Pinellas Plant received an electrical shock
when he made contact with a 480-volt bus as he tightened a conduit lock nut on a switch.
The electrician did not check for energized equipment before putting his hand on the
switch (ORPS Report ALO-PI-GEND-PINELLAS-1990-0036).
These events emphasize the importance of incorporating industry standard electrical
safety practices into work habits and work planning. Failure to do so can result in serious
personnel injuries or fatalities. Continuing training on electrical safety methods for all
personnel working on electrical equipment should be considered. Information on industry
standard practices for electrical safety may be found in American National Standards
Institute/Institute of Electrical and Electronic Engineers (ANSI/IEEE) C2, National
Electrical Safety Code.
ADDITIONAL INFORMATION RELATED TO FOLLOWUP ACTIVITIES
1. IDAHO TEST REACTOR AREA HOT CELL RADIATION STREAMING EVENT
CORRECTIVE ACTIONS
In OE Weekly Summary 92-11, NS described an event at the Test Reactor Area Hot Cell
(TRAHC) facility in Idaho where on March 18, 1992, facility personnel discovered a
radiation stream measuring 2 rem/hour from a hot cell wall. The radiation stream was
discovered during a routine radiation survey being conducted in conjunction with Cobalt-
60 processing in the hot cell. Radiation protection personnel traced the stream to a small
collimator opening (1/2 inch by 3/4 inch) in the four-foot thick shielding wall. The stream
was produced when the Cobalt-60 being processed in the cell was positioned directly in
line with the collimator. (ORPS Report ID--EGG-TRAHC-1992-0003)
An investigation into the event lead to the determination that an Unreviewed Safety
Question (USQ) existed based on the lack of a bounding analysis for radiation exposure
to a TRAHC worker. The determination of a USQ required that the facility be placed in
a shutdown condition pending Type 2 restart approval. In September, 1993, NS received
the following information from TRAHC personnel describing activities that have taken
place since the facility was shut down.
As a result of the event a detailed corrective action plan was developed for facility
recovery. The recovery strategy addressed all areas of facility operations including
management, technical safety basis, material condition, procedures, conduct of
operations, radiological improvements, and detailed operator retraining.
The management organization was revised by the contractor to more directly include the
TRAHC facility into the Power Reactor Program (RPT) Group and Department level
organizations. The facility Safety Analysis Report (SAR) and Technical Safety
Requirement (TSR) documents were completely rewritten to conform to DOE Order
5480.23 and 5480.22.
The contractor completed an "as built" review of all necessary facility drawings and
completed repairs of all electrical and ventilation systems. All cell shielding was
inspected and upgraded as required to restore it to original construction design, and
detailed radiation surveys were conducted to establish a safety basis for operation. All
facility operating procedures were rewritten incorporating appropriate radiological, safety,
and conduct of operations requirements, and these procedures were included into the
Department's process for configuration control.
The facility was extensively cleaned, decontaminated, and repainted. As a result, the
incidence of contamination events has decreased by more than 80%. Notable ALARA
improvements in operations have reduced personnel exposure for cell entries by a factor
of seven. An historical dose evaluation was completed to estimate TRAHC personnel
exposure from any historical streaming events. A facility wide automated dosimetry
tracking system has been implemented to efficiently monitor and control both personnel
and total job exposures.
The facility training and qualification programs were revised in accordance with the
requirements of DOE Order 5480.20 and all personnel in the facility were re-qualified.
The re-qualification process placed considerable emphasis on conduct of operations
philosophy, facility safety basis documentation, and procedure changes made to support
TRSs. Long range training plans were developed and put in place to conduct ongoing
training in conduct of operations and radiological safety.
These recovery activities have restored the operational safety and reliability of the facility.
A thorough review of the facility status was recently completed during a Operational
Readiness Review (ORR). The small number of minor findings made during the ORR
indicate that the contractor management has successfully corrected the issues which led
to the facility shutdown, and have established a new standard of material and personnel
performance readiness.
SAFETY NOTICES UNDER DEVELOPMENT
Note: The Office of Nuclear Safety encourages input related to the development of Safety
Notices. If you have any questions, comments, or information concerning events or
issues similar to the following, please contact Mr. Dick Trevillian, Office of Nuclear Safety
at (301) 903-3074.
1. NS has identified a number of events related to the loss of annunciators and other
safety-related equipment because of problems involving 120-VAC/125-VDC systems
at DOE and commercial facilities. NS is reviewing potential generic problems
associated with the adequacy of 120-VAC/125-VDC systems at DOE facilities.
2. NS evaluated three events associated with the temporary diesel generator at the
Rocky Flats Plant, Building 707. The lessons learned from these events, particularly
as they relate to the control of temporary modifications, are being considered for
dissemination in an NS Safety Notice.
3. NS is developing a Safety Notice concerning problems with Uninterruptible Power
Supplies (UPS).
4. NS is considering development of a Safety Notice related to control of work at
electrical substations and switchyards.
5. NS is working with Lawrence Livermore National Laboratory and DOE-SF personnel
to develop a Safety Notice on cracking in ventilation ducting.
6. NS is considering developing a Safety Notice related to fuel oil supplies for
Emergency Diesel Generators (EDGs).
7. NS is developing a Safety Notice to address uses of independent verification for
equipment positioning.
8. NS is developing a Safety Notice related to maintaining important alarm and
monitoring systems at facilities undergoing transition and decontamination and
decommissioning.
SAFETY NOTICES PREVIOUSLY ISSUED
Safety Notice No. 91-1, "Criticality Safety Moderator Hazards," September 1991
Safety Notice No. 92-1, "Criticality Safety Hazards Associated With Large Vessels,"
February 1992
Safety Notice No. 92-2, "Radiation Streaming at Hot Cells," August 1992
Safety Notice No. 92-3, "Explosion Hazards of Uranium-Zirconium Alloys," August 1992
Safety Notice No. 92-4, "Facility Logs and Records," September 1992
Safety Notice No. 92-5, "Discharge of Fire Water Into a Critical Mass Lab," October
1992
Safety Notice No. 92-6, "Estimated Critical Positions (ECPs)," November 1992
Safety Notice No. 93-1, "Fire, Explosion, and High-Pressure Hazards Associated with Drums
and Containers," February 1993
Copies of NS Safety Notices may be requested from: Nuclear Safety Information Center,
Office of Nuclear Safety, U.S. Department of Energy, Room S161, GTN, Washington, DC
20585