NS OPERATING EXPERIENCE WEEKLY SUMMARY 93-2
January 8 - January 14, 1993
The purpose of the NS Operating Experience (OE) Weekly Summary is to enhance
safety throughout the DOE complex by promoting the feedback of operating experience
and by 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 January 8 - January 14, 1993.
ITEM PAGE
1. ADMINISTRATIVE RADIATION EXPOSURE LIMITS EXCEEDED 1
2. LOSS OF CRITICALITY CONTROL AT FUEL FABRICATION FACILITY 2
3. TANK OVERFLOW AT SRS H-CANYON 3
4. OVERHEATED PRODUCTION CELL 3
5. CONTAMINATED HAND INJURY IN GLOVE BOX 4
6. DIVERSION VALVE FAILS FUNCTIONAL CHECK 5
7. CRYSTALLIZATION OF POTASSIUM HYDROXIDE (KOH)
IN PIPE CAUSES PUMP FAILURE 5
8. CONFINED SPACE ENTRY WITHOUT REQUIRED PERMITS 5
9. UNAUTHORIZED CRANE MODIFICATION CAUSES NEAR MISS 6
10. SEVERE HAND INJURY FROM IMPROPER POWER TOOL MAINTENANCE 7
11. FIRES AT CHERNOBYL 8
12. ELECTRICAL FAILURE IN HAWORTH POWERED PANEL 8
1. ADMINISTRATIVE RADIATION EXPOSURE LIMITS EXCEEDED
On January 8, 1993, dosimetry personnel at Hanford determined that five employees
had exceeded their administrative Lifetime Control Level (LCL) of N rem where N is
the age of the employee in years. The dosimetry personnel notified the employees
and facility managers. Facility managers placed the employees on radiation work
restriction pending the establishment of special control levels in accordance with
Article 216 of the Radiological Control Manual (RCM) (ORPS REPORT RL--WHC-WHC200EM-
1993-00030).
The LCL of N rem and the methodology for calculating total dose were recently
established by the DOE RCM (DOE N 5480.6, effective June 1992). Prior to this, the
total dose was calculated by summing an individual's external dose (documented TLD
readings etc.) and the person's annual effective dose equivalent from internal
depositions. However, the revised administrative limit defines total dose as the sum
of the individual's external dose plus his 50 year committed dose from internal
depositions. The 50 year committed dose is defined as the dose rate due to the
deposition, calculated over the fifty year period following the deposition. The total
dose for the fifty years is assigned to the current year (year of the deposition) totals.
Consider an example: A radiation worker age 58 (therefore with an LCL of 58 rem)
has a lifetime accumulated dose of 10 rem, an internal deposition exposure of 1 rem
and a current year external dose of 3 rem. His total dose used to be calculated as
follows: a previous total of 10 rem, plus 1 rem internal dose from current the
contribution, plus the current external dose of 3 rem, for a total of 14 rem or 44 rem
less than his LCL.
Article 212 of the RCM now requires that his dose be calculated as follows; 10 rem
previous total, plus 3 rem current external dose plus perhaps 50 rem committed dose
equivalent. The actual 50-year committed dose equivalent will depend on the
biological half-life of the ingested contaminant plus other factors. The total thus
becomes 63 rem. The worker exceeds his LCL of 58 rem by 5 rem and must be
placed on radiation work restriction.
Article 216 of the RCM allows for establishing special control levels provided certain
requirements are met. For example, special controls may be established when the
worker's remaining natural life span is less than 50 years (as would be the case in the
example above).
10#CFR#20 was revised to contain similar changes affecting the commercial nuclear
industry radiation worker. These changes incorporate advances in scientific
knowledge and implement the 1987 presidential guideline on occupational radiation
exposure.
Changes brought about by implementation of the DOE RCM need to be reviewed with
radiation protection personnel in detail, because the description given above is only
a simplified example of the effects of the changes. As the nuclear industry strives
to improve the protection of exposed workers, it is essential to stress and implement
the ALARA concept to meet these challenges. ALARA should be a major
consideration in every work plan.
2. LOSS OF CRITICALITY CONTROL AT FUEL FABRICATION FACILITY
On January 12, 1992, personnel at a General Atomics uranium fuel fabrication facility
in San Diego, California notified the NRC of a loss of a criticality barrier. General
Atomics manufactures fuel for TRIGA research reactors at this facility. One step in
the process involves melting a zirconium-uranium metal mixture in an induction heated
mold inside a casting furnace. The mold is surrounded by insulation and a water
cooled jacket. A mold heated to approximately 1900 degrees centigrade in the
furnace, developed a pin-hole leak in the water-cooled jacket allowing water to enter
the insulation. The water flashed to steam causing the mold to be ejected out of its
holder and the molten metal mixture to be dispersed inside the furnace. Because of
the limited quantity of uranium in the batch, there was no possibility of a criticality
accident existed. However, dispersement of the metal mixture constituted a loss of
geometry and therefore a criticality control violation. All material was contained
inside the furnace. (NRC event number 24865)
As part of its investigation of this event, the NRC noted that the facility s safety
analysis report (SAR) did not consider this accident scenario and had therefore not
analyzed the potential consequences. This event serves as a reminder for DOE
nuclear facility personnel to ensure that all credible accident scenarios are identified
and analyzed in their facility s SAR. Information on criteria for nuclear SARs can be
found in DOE Order 5480.24, Nuclear Safety Analysis Reports.
3. TANK OVERFLOW AT SRS H-CANYON
On January 7, 1993, at the Savannah River Site's (SRS) H-Canyon 211 H facility, an
operator noticed the E-3-3 holding tank level stabilize, then begin to decrease
unexpectedly, during a routine transfer of potentially contaminated rainwater from the
F-1-6 catch basin sump to the tank. The operator immediately stopped the transfer
and sent another operator to inspect the tank area. The second operator reported the
tank was overflowing. The overflow drained back to the F-1-6 sump so no cleanup
was required.
The operator had verified the tank level on a computer screen before starting the
transfer to ensure sufficient tank volume was available, as called for by the facility
procedure. Preliminary investigation discovered that, while the level detector
operated correctly, either the level transmitter or the data link to the computer screen
had failed. The time and reason for either failure is currently under investigation; these
level instruments are included in the facility's measuring and test equipment program.
Although the tank overflowed, the operator demonstrated good conduct of operations
practice regarding equipment monitoring and responding proactively to indicators.
The operator was alerted to this event by monitoring the level indication, and if she
had not noticed it, the cycle might have continued for a much longer time. Facilities
need to encourage a similar level of attention to detail and a questioning attitude by
their operators.
4. OVERHEATED PRODUCTION CELL
On January 7, 1992, operator inattention and failure to completely restore from
maintenance testing caused a production cell to overheat at the Paducah Gaseous
Diffusion Plant. Operations and Instrument Maintenance personnel were conducting
routine maintenance testing of coolant and seal system alarm setpoints. As part of
the testing, operators placed a pneumatic controller in the seal mode. Placing the
controller in this mode seals the air pressure to the control valve, and the valve will
either remain in the same position or move if pressure in the air line decreases. After
completing the test, operators did not return the controller to its normal position.
Because the test was performed routinely by trained personnel, there was no
procedure or checklist for system restoration following the test.
Some time later, a local cell monitoring system alarmed in the control room. The
alarm was indicated by an alarm printer, an annunciator light, and an audible general
alarm. Facility personnel silenced the available alarm, assuming alarm testing was still
in progress. The control room operators did not realize an actual alarm condition
existed until about 50 minutes later. Other alarm testing activities being conducted
at the same time may have contributed to the unrecognized alarm condition. Control
room operators then dispatched an operator to the local cell panel. The operator
arrived at the local panel and noticed that the cell temperatures were above the
operating limit. Operators then shut down the cell in accordance with facility
procedures. (ORPS Report ORO--MMES-PGDPCASOPS-1993-0001)
No damage to the cell resulted from the overheated condition. Had the operators not
identified the alarm condition and shut down the cell, the cell monitoring system was
designed to automatically shut down the cell when a high coolant pressure setpoint
was reached.
This event emphasizes the need for operators to be especially alert to the possibility
that alarm testing could mask actual alarm conditions. Every alarm should be verified
prior to acknowledging and silencing. The event also illustrates the benefits of using
procedures or checklists when conducting testing activities, even routinely performed
tests.
5. CONTAMINATED HAND INJURY IN GLOVE BOX
On January 6, 1993, at Argonne National Laboratory-West (ANL-W), a laboratory
worker, preparing a glovebox for decontamination, cut his hand and contaminated the
wound (ORPS Report CH-AA-ANLW-1993-0001). The worker was preparing pieces of a
broken glass beaker and other miscellaneous items for removal from the glovebox.
He was attempting to wrap duct tape around a plastic bag containing the broken
glass to prevent sharp edges from damaging the outer bag-out sleeve and to maintain
a 9-inch dimensional limit to permit passage through the access door. Wrapping
contaminated sharp objects with tape to prevent damage to vinyl bag-out sleeves is
a standard practice at ANL-W.
While wrapping the bag, the worker's hand slipped and the resultant impact caused
a piece of glass to penetrate the bag and the worker's glove in the glove port. The
worker sustained a puncture wound on his right palm. An ANL-W Radiation Safety
technician found contamination in the wound. After the contamination was reduced
to about 100 counts alpha, the worker went to a central dispensary for continued
decontamination and treatment. Additional gamma monitoring of the injured hand
was negative and a whole body count was normal. Bio-assay samples were also
collected to determine whether any measurable uptake occurred.
In the future, ANL-W personnel plan to use metal containers to collect contaminated
broken glass, and their lids will be taped down prior to placement in the vinyl bag-out
sleeve. The facility is phasing in the use of metal beakers.
OE Weekly Summary 92-36 reported a similar event at the Savannah River Tritium
Facility. On December 20, 1992, an operator removing a small O-ring from a
contaminated component with a dental-pick probe, slipped and punctured the anti-
contamination glove on his left hand, breaking the skin on his palm (ORPS Report SR--
WSRC-TRIT-1992-0069).
These events point out the importance of using extreme care when working with
sharp objects in a radiation contaminated environment. A wound sustained under
such circumstances can be difficult to decontaminate. Facilities should consider
alternate methods of handling contaminated sharp objects and substitute, where
possible, unbreakable laboratory equipment for glovebox use.
6. DIVERSION VALVE FAILS FUNCTIONAL CHECK
On January 10, 1993, an electrically powered diversion valve at the Savannah River
F-Canyon failed to operate during a weekly functional check. Facility personnel were
also unable to manually operate the valve (ORPS Report SR--WSRC-FCAN-1993-0002). This
failure is significant because the diversion valve redirects canyon cooling water to a
retention basin if high activity is detected in the cooling water. During normal
operation, the cooling water is either recirculated through a cooling tower or
discharged into a creek feeding into the Savannah River. Until the valve is repaired,
operators can manually divert the cooling water by using several system drain valves.
Facility personnel have categorized this valve as a Critical Protection component and
operators functionally test it on a weekly basis. During troubleshooting efforts,
maintenance personnel identified a failed shear pin on the Limitorque valve actuator
which prevented valve operation. Facility personnel are investigating the cause of the
pin failure. NS will follow this item and report as necessary on the cause of the shear
pin failure.
7. CRYSTALLIZATION OF POTASSIUM HYDROXIDE (KOH) IN PIPE CAUSES PUMP
FAILURE
On December 30, 1993, at the Hanford Uranium Oxide (UO3) Facility, a Condensate
Neutralization system pump failed because KOH solidified in a pipe line. In addition,
a manual valve downstream of the pump could not be operated because of the
solidified KOH (ORPS Report RL--WHC-UO3-1993-0002).
Facility personnel replaced the affected pump and valve and restarted the system on
January 7, 1993. Investigation determined that changing from 45 WT% KOH to 50
WT% KOH had caused the solidification. Facility personnel had recently begun using
50 WT% KOH because a surplus of this concentration was available from an adjacent
facility.
Recent abnormally cold weather at the Hanford Site contributed to the occurrence.
Because of UO3 facility plans to continue using 50 WT% KOH, facility personnel
covered the KOH tank and relevant piping with steam jacketing.
This event involves fundamental chemical and process engineering problems. Before
a solution concentration or a weight percentage is changed, the modification must be
evaluated, taking into consideration such things as system pressures, ambient
temperatures, pumping requirements, etc. to ensure that the process will not be
degraded by the proposed modification. When facilities, for economic reasons, take
advantage of excess supplies with different characteristics than had been used
before, a thorough engineering review of potential deleterious effects is required to
help prevent unnecessary downtime and equipment replacement.
8. CONFINED SPACE ENTRY WITHOUT REQUIRED PERMITS
On January 6, 1993, Health Physics (HP) technicians at the Idaho Chemical
Processing Plant (ICPP) entered the CPP-604 WL-101/102 vault and performed a
comprehensive radiation and contamination survey. The technicians did not have a
completed Hazardous Work Permit (HWP) for the vault entry. An Operations Shift
Manager (SM) and an HP Supervisor approved the vault entry. The HP technicians
wore supplied-air respirators and personnel extraction gear. A back-up extraction
team stood by the access hatch during the entry.
The survey was a part of the pre-job activity called for in a Special Procedure (SP)
(CPP-604 WL-101/102 "Vault Decontamination") to decontaminate the vault to allow
a construction contractor to line the vault floors and wall to comply with the
Resource Conservation and Recovery Act. The SP directed all activities necessary to
complete the job. It included a pre-job survey and required that HP technicians obtain
an HWP. The SM who approved the entry for the survey had himself initiated a
request for an HWP for the work. The HP technicians submitted the HWP request to
the Industrial Safety supervisor for review and approval. He told them that more
steps needed to be completed before he could approve the HWP. The HP technicians
reportedly thought the pre-job survey was one of the steps to be completed before
the HWP could be approved. Before the SM approved the entry, he asked the
technicians whether they had everything they needed (including the HWP). They
responded that they did, thinking that the survey needed to be done to get the HWP
approval.
The requirements for issuing an HWP include an atmosphere survey for oxygen
concentration, a pre-job briefing, extraction gear, and the staging of a back-up
extraction team at the access point. All the elements required for the HWP were in
place, with the exception of the atmosphere sampling and the pre-job briefing.
Because the technicians wore supplied-air respirators, the lack of an atmosphere
sample was considered insignificant. No injuries resulted from the event.
The WL-101/102 vault, a concrete shell, contains two waste holding tanks. One of
the tanks holds intermediate waste water for processing through process equipment
waste (PEW) evaporators. The other tank receives the concentrated waste after
processing. Potential hazards associated with entry into this vault include nitrous
oxide gas, radioactive gases, airborne radioactive contamination and an oxygen
deficient atmosphere.
The cause of this event was a breakdown in communications between the SM, the
Industrial Safety supervisor and the HP Technicians. The involved personnel assumed
important information rather than communicating and verifying it. This event
illustrates the importance of complete communications, including repeating back
essential items. In this case no one was injured because the technicians used the
appropriate equipment and back-up personnel were on hand, and no hazard was
present at the time. Facilities should use procedures to avoid reliance on memory and
assumption, but without adequate communications even the procedures will not
always be sufficient to ensure a safe approach to the job.
9. UNAUTHORIZED CRANE MODIFICATION CAUSES NEAR MISS
On December 11, 1992, at the Argonne National Laboratory-East Plant Facilities
Services (PFS) area, an assembly consisting of a piece of Unistrut and an iron casting
weighing approximately seven pounds fell about 15 feet from an overhead 4-ton
bridge crane trolley. The assembly missed hitting a plant employee by less than two
feet. The assembly had been attached to the overhead crane as a trolley travel stop.
It was not part of the original trolley design nor was it an authorized modification of
it.
Facility personnel stopped the crane and locked it out of service. PFS crane
maintenance and safety personnel reconstructed the incident and found that two
modifications had been made to the crane. The first modified the power connector
follower attached to the bridge. The hoist is the only electrically operated component
of this crane. It requires a power cable and connector that must track with the bridge
and trolley to provide power to the hoist motor. A chain attaches the connector to
the bridge. For unknown reasons the chain had been shortened, thus bringing the
connector within the trolley's range of travel.
The second modification added the Unistrut and casting assembly that fell from the
trolley. This "home made" trolley stop apparently had been installed because the
trolley had been contacting the hoist power connector before reaching the
manufacturer installed trolley stop, apparently due to the first modification.
The crane maintenance group re-located the power connector out of the trolley travel
path. The manufacturer installed trolley stop functioned properly with the hoist cable
power connector in its correct location. Facility personnel could not determine when
the modifications had been made.
This event illustrates that unauthorized modifications to facility equipment may cause
equipment failures. Facility modification procedures provide a formal method for
review, approval and documentation of changes to facility components, systems or
structures. Bypassing any of these steps can create hazardous conditions. Review
and approval of facility modifications, whether permanent or temporary, should
include consideration of potential impacts on facility procedures, training,
procurement, maintenance, operations and safety.
10. SEVERE HAND INJURY FROM IMPROPER POWER TOOL MAINTENANCE
On January 6, 1993, at Lawrence Livermore National Laboratory, an employee was
cleaning and inspecting a rotating grinding wheel and cutting blade when the small
and ring fingers of his left hand were severed (ORPS Report SAN--LLNL-LLNL-1993-0001).
The employee inadvertently placed his hand in a position where the rotating wheel
pulled his fingers into a point where they were pinched with the knife edge. Normal
operating practice requires the blade to be backed away from the grinder prior to
inspection. There was no written procedure for this task. Also, machine guards did
not fully cover the blade/grinding wheel area. The injured employee was transported
to a local hospital where both fingers were reattached. Facility personnel locked and
tagged the machine out of service, and began a lab wide survey of machine tool
guarding.
All machine tool equipment should be inspected and evaluated for compliance with
OSHA safety standards. Facilities should provide employees engaged in operation
and maintenance of machine tools with necessary training and up to date procedures
or instructions that address safety hazards. The risk of severe injury may be reduced
by establishing various barriers to prevent rotating machine hazardous parts from
contacting worker's hands, etc. These barriers usually inspection to ensure
compliance with applicable standards, training of operators and maintenance
personnel, and written precautions.
11. FIRES AT CHERNOBYL
On January 13, 1993, a small fire broke out at the Chernobyl nuclear power station
located 80 miles north of Kiev, Ukraine. Ukrainian nuclear officials stated that the fire
occurred in a room between the station's first and second reactors and was quickly
brought under control. There was no change in radiation levels at the facility.
Although the cause of the fire is under investigation, officials speculate that the blaze
could have been started after melted snow dripping from the roof caused a short
circuit in an auxiliary electrical unit that supplied power to welding equipment. The
fire did not affect the two operating reactors at the site. On January 14, 1993,
another fire occurred in the ventilation corridor above the cement sarcophagus that
covers the Unit No. 4 reactor core. Site personnel quickly extinguished the blaze and
no radiation was released. This is the fourth blaze reported at the Chernobyl complex
since the April 1986 explosion and fire spread radiation over a wide section of
Ukraine and Belarus. Another fire in November 1991 damaged the generator room
of reactor No. 1 (Newswire Service).
12. ELECTRICAL FAILURE IN HAWORTH POWERED PANEL
On January 4, 1992, in the Drafting Office area at Sandia National Laboratory's
Livermore Site, employees heard a breaker trip and simultaneously witnessed a spark,
then a flash, from a power connector at the bottom of a Haworth Powered Panel
System panel. This system is a room divider with electrical power outlets in the
raceway at the base of each panel. The employees found a small scorched area on
each side of the panel, and the plastic connector was partially melted (ORPS Report ALO-KO-
SNL-LVMRSITE-1993-0001). A similar occurrence was reported in UOR-90-17, dated 5/14/90.
These panels have been in service at this site for about ten years. They are designed
for a 20-amp load. However, the manufacturer recommends a 16 amp load for
extended use. On the morning of January 4, 1993, employees had just returned from
holiday. Six employees powered up their work stations, i.e. computers, desk lights,
etc. One employee plugged in a 13-amp heater because it was cold in the area. This
additional electrical load apparently caused the failure of the panel.
One of the most common hazards in the home or the work place is overloading of
electrical outlets. (Electrical load in amps can be determined by dividing the device
nameplate wattage by the circuit voltage.) In this case, a 1500-watt heater drew
about 13 amps (1500 watts divided by 115 volts). In the last decade, increased use
of electrical equipment in the work place has challenged the capacity of many
electrical circuits. Facility personnel should ensure adequate margins of safety are
maintained for partitions containing circuits and electrical outlets, especially if they
service work station locations.
ADDITIONAL INFORMATION RELATED TO FOLLOWUP ACTIVITIES
1. ADDITIONAL LOCK-OUT/TAG-OUT NONCOMPLIANCES
Lock out/Tag out (LO/TO) problems were the subject of recent items in the NS
Operating Experience Weekly Summary (Inadequate Interface Between Construction
and Operations Tag-outs, NS 92-33; Improper Lock-out/Tag-out Incidents, NS 92-35).
Two recent events at Hanford merit this follow-up report.
On January 8, 1993, in the Hanford tank farms, a work package was released
to perform work related to the installation of an emergency diesel generator at
Building 701-A. A LO/TO was approved and installed on day shift except for
final verification which was to consist of an independent check of the LO/TO
by an operator and a supervisor. Due to a shift change and the fact that the
actual work was performed by contractor personnel, the work commenced
without the required final verification being done.
On December 28, 1992, at the Plutonium Finishing Plant, a LO/TO was installed
to assure the de-energizing of a breaker on an electrical panel. Later, the LO/TO
Custodian allowed the LO/TO tags to be removed for switch testing by
electricians. After testing, the LO/TO tags were re-hung without the required
independent verification of the LO/TO. Over the next ten days the LO/TO tags
were removed and replaced two more times.
In both of these cases managers recognized after the fact that a procedural violation
had occurred. In dealing with LO/TO situations, compliance with procedures is
MANDATORY to assure personnel safety. Where work extends over several shift
crews, and contractor personnel are involved in performing maintenance tasks,
communication is vital to ensure that procedural requirements are completed before
the work is initiated.
2. FOLLOW-UP ON LITHIUM FIRE IN WASTE HANDLING FACILITY
OE Weekly Summary 92-36 reported a lithium fire on December 14, 1992, at the
Lawrence Berkeley Laboratory (LBL), as contractor personnel were preparing lithium
ribbon for packing. The lithium was being prepared by immersion in methanol inside
a fume hood designed for handling hazardous materials. The lithium ignited as it was
being immersed in the methanol (ORPS Report SAN--LBL-EHS-1992-0012).
Additional information indicates that mineral oil should have been used for immersing
the lithium, since methanol is readily miscible with water. The site disposal guide
used by contractor employees performing the work merely called for "a solvent"
rather than specifying mineral oil.
Two additional lessons were learned by the LBL staff from their review of this
incident. First, the generator of the waste lacked the training and knowledge to
package the lithium correctly, as evidenced by the fact that he had left it in a bag
under the fume hood. Had he placed the lithium properly in mineral oil, the contractor
personnel responsible for waste disposal would not have had to attempt to immerse
it themselves.
Second, the contractor personnel should not have attempted to prepare it for disposal
without notifying the responsible individual that it had not been packaged correctly.
The contractor was a certified waste handler, but his procedure was in error.
Vendors have been required to change procedures and retrain their personnel. In
addition, LBL staff will now provide strict oversight of vendor staff during the
collection, transfer, and packaging of waste.
Facilities that routinely handle combustible metals should ensure that employees are
trained in extinguishing metal fires. A good reference would be the National Fire
Protection Association Standard (NFPA FPH SEC 5-21), "Combustible Metal
Extinguishing Agents and Application Techniques."
3. FOLLOW-UP ON DIESEL GENERATOR CYLINDER HEAD PROBLEMS
OE Weekly Summary 92-32 discussed problems reported by Gulf States Utilities
(GSU) regarding potential problems in Type R-4 diesel generators (DGs) under the
manufacturer name Enterprise Engine Company or IMO-DeLaval. Cooper-Bessemer
has since acquired IMO-DeLaval and now has the responsibility of notifying owners
of the suspect cylinder heads. (NRC EN 24655). Cylinder heads in these DGs cast
before August 1, 1984 may have inadequately thick walls. The problem was
discovered during an investigation at the River Bend nuclear power plant on October
15, 1992. On that date a diesel generator was taken out of service to investigate
traces of engine coolant found in lubricating oil samples. The source of the coolant
was identified to be a minute leak from the number four cylinder head into the valve
train area, where it drained to the engine base. This event is documented in a 10
CFR Part 21 report (#92-248) to the NRC dated November 16, 1992.
On December 17,
1993, Cooper-
Bessemer provided
further identification
of the affected heads
to the NRC and
owners of their
diesel engines. The
final report identifies
affected heads by
serial number and
contains recom-
mended corrective
action.
The root cause for
the failure at GSU
was inadequately
thick cast walls at
the 3/4"-10 bolt hole
indicated on a sketch
supplied for the 10
CFR Part 21
notification (Figure
1). Cooper-Besse-
mer Design
Engineering has
reviewed the design
drawings to determine whether any other sub-cover bolt holes do not have adequately
thick walls between the bolt hole and the adjacent water passage. Their review
revealed no other bolt holes with inadequate wall thickness.
The affected cylinder heads are identified by one of the following part numbers: 03-
360-03-0F, 1A-6446, 1A-6447, 1A-6879, 1A-6240, 1A-6239, 1A-7062, 1A-5559,
1A-5558, 1A-6266, or 1A-6265, all of which were cast prior to August 1, 1984.
Identification of individual heads may be accomplished by referring to Figure 1 and
from the following information:
All heads have the cast serial number, heat number, cast date,
manufacturing date, water test, air test, gas test, and possibly
reconditioning information stamped on the head. At Area 1 on Figure 1,
which is inside the sub-cover, the serial number, heat number and cast date
should be stamped with minimum of ¨" size letters. Area 2 on Figure 1,
which is outside the sub-cover on the head, includes serial number, heat
number, manufacturing date, water test, air test, gas test information and
possibly reconditioning data.
Area 1 should be examined for the cast date as stamped by the Enterprise foundry
with steel stamps. This may be difficult to see as this area has been painted. Other
clues to the age of the cylinder head are at Area 2. If the serial number is L99 or less,
and the manufacturing date is before 1986, it is most likely a cylinder head cast prior
to August 1, 1984. Any questions concerning cast dates and serial numbers should
be directed to John R. Schneider, Manager, Quality Assurance at 412-458-3434.
Corrective action includes removing the stud at the location shown in Figure 1 and
applying Loctite Hydraulic Sealant (Item No. 56931) or equivalent, per Loctite instru-
ctions, to the threaded hole and stud. Tests at Cooper-Bessemer conducted on
December 7, 1992, proved this repair sufficient to withstand 100 psi of water
pressure (hot or cold) without leakage. Cooper-Bessemer Service Information Memo
#384 is being issued which explains this procedure in more detail. This corrective
action should be performed at the next scheduled diesel engine outage.
Corrective action at Cooper-Bessemer will be to repair this head section on all
affected cylinder heads returned to them for rebuilding or repair, using their standard
repair EAR-11-001. This involves drilling the hole 1/8" oversize and 1/8" deeper,
filling the hole completely with weld metal, redrilling and re-tapping to blueprint size
and depth, and re-hydrotesting.
Managers of DOE facilities with Type R-4 DGs manufactured by Enterprise Engine
Company or their successor, IMO-DeLaval, should determine whether the cylinder
heads on their units have this problem, and take appropriate remedial actions.
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 those described below, please contact Mr. Ivon Fergus, Office of
Nuclear Safety (301) 903-6364.
1. NS has identified a number of events related to the loss of annunciators and
other safety-related equipment caused by 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
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 developing a Safety Notice related to control of work at
electrical substations and switchyards.
5. NS is developing a Safety Notice related to the handling, storage, venting, and
opening of containers and drums that may be pressurized or may contain
flammable vapors. This notice will contain generic information about proper
storage conditions and the material conditions of containers.
6. NS is working with Lawrence Livermore National Laboratory and DOE-SF
personnel to develop a Safety Notice on cracking in ventilation ducting.
7. NS is considering developing a Safety Notice related to Emergency Diesel
Generator (EDG) fuel oil supplies.
8. NS is developing a Safety Notice addressing uses of independent verification for
equipment positioning.
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
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