NS OPERATING EXPERIENCE WEEKLY SUMMARY 93-10
March 5 - March 11, 1993
The purpose of the NS Operating Experience (OE) Weekly Summary is to enhance
safety throughout the 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 March 5 - 11, 1993.
ITEM PAGE
1. DIESEL GENERATOR FAILS TO START DURING TEST 1
2. PROCEDURE VIOLATION BY FIRE WATCHER 2
3. MISSING INSTRUMENT CHECK SOURCE 3
4. LOW FLASHPOINT OF DIESEL FUEL OIL 3
5. CAUTION REGARDING THE PACKAGING OF METALLIC URANIUM
IN STEEL DRUMS 4
6. INCORRECT CIRCUIT BREAKER OPERATION CAUSES REACTOR
TRIP BREAKERS TO OPEN 5
7. OPERATIONAL SAFETY REQUIREMENT VIOLATION CAUSED
BY FAILED TANK LEVEL INSTRUMENTATION 6
8. INADVERTENT LIQUID WASTE TRANSFERS 6
9. RADIOACTIVE DISCHARGE FROM SHUTDOWN FACILITY 7
10. PERSONNEL INADVERTENTLY DISCONNECT FUEL HANDLING UNIT
FROM HOOK 8
FINAL REPORTS - SUMMARIES
1. FAILURE OF REACTOR COARSE LEVEL INDICATION 9
1. DIESEL GENERATOR FAILS TO START DURING TEST
On March 5, 1993, in the Laboratory Technical Area (LTA) at Savannah River,
operations personnel were unable to perform a no-load start test on the 792-A Sand
Filter Diesel Generator. The LTA is the general research and development laboratory
for the entire Savannah River Site and handles many hazardous substances. The
diesel generator provides emergency power to maintain the exhaust flow through the
sand filter in the event of a facility loss of power. The Sand Filter is a large (100' x
150') underground structure downstream from the HEPA filters. It is intended to
provide a last barrier to filter air that may contain radioactive isotopes. Failure of
facility power combined with the failure of the diesel generator could cause
ventilation problems in the 773A facility, where many glove boxes and hot cells are
in use, and could result in spreading contamination throughout the facility and
possibly into the environment (ORPS REPORT SR--WSRC-LTA-1993-0014).
The initial investigation erroneously concluded that the battery did not have sufficient
cranking power to start the diesel. The investigators knew that the battery was fairly
old and was scheduled for replacement soon, although it still met the minimum
specification requirements for the system. The batteries were recharged for two
hours on a trickle charger, but the diesel still would not start. The batteries were
then warmed to increase their efficiency, and a diesel starting fluid was injected into
the diesel's air intake to assist starting, but the unit still would not start.
Maintenance and engineering personnel found the damper on the air intake line was
unable to open, as required for normal operation. The problem was not noticed when
investigators used the diesel starting fluid, because they injected the fluid into the
intake piping at a point downstream of the stuck damper. The damper was opened
and the unit started and ran without further problem. The investigation is continuing
to determine whether the damper problem is mechanical or electrical.
2. PROCEDURE VIOLATION BY FIRE WATCHER
On March 5, 1993, in Building 707 at Rocky Flats, a shift technical adviser found that
an employee providing a continuous fire watch on the second floor of the building
was not performing his required duties. The purpose of this facility is to conduct
thermal stabilization operations for the Rocky Flats site, including oxidation operations
of plant inventory and duct remediation. Fire watches in this facility are required to
meet the Operational Safety Requirements for previously identified safety deficiencies.
The main safety function of the fire watch is to cover those areas that do not have
a functional automatic fire detection system. The individual was reading a magazine,
and the fire watch log-sheet that documents completion of the fire watch inspections
had been filled out twenty minutes in advance. The individual concerned was relieved
of his duties pending the completion of the investigation (ORPS REPORT RFO--EGGR-PUFAB-
1993-0047).
Facilities are encouraged to review DOE Safety Notice 92-4, "FACILITY LOGS AND
RECORDS", (September 1992), by the Office of Nuclear Safety. The notice
summarizes situations at DOE facilities where logs were falsified, incorrectly entered,
or not completed. Readers are reminded that such practices are inconsistent with
DOE requirements and guidelines.
Additional related commercial industry experience is discussed in Nuclear Regulatory
Commission Information Notice (IN) 92-30, "FALSIFICATION OF PLANT RECORDS."
Quoting from Safety Notice 92-4, "DOE and commercial industry experience
emphasizes the potential adverse impact of improper logkeeping on nuclear safety,
as well as representing possible violations of Federal regulatory requirements and
criminal statutes."
3. MISSING INSTRUMENT CHECK SOURCE
On March 2, 1993, personnel at the Oak Ridge National Laboratory were unable to
locate a 0.2 uCi thorium-232 check source, creating a potential hazard that facility
personnel could be unknowingly exposed to radiation. Facility personnel were
performing the semi-annual leak test of HFIR sources when they identified the source
as missing. Several searches failed to locate it (ORPS Report ORO--MMES-X10ENVIOHP-1993-
0002).
There have been many instances at DOE facilities of improper disposal and loss of
control of radioactive sources. On December 22, 1992, personnel at the Chem-
Nuclear Geotech facility discovered an uncontrolled cobalt-60 source on the ground
outside the Source Storage Building at the Grand Junction Project Office during a
routine weekly survey. Dose rates from the source were 220 millirems/hour on
contact. Facility personnel verified that the site did not have a source of this type in
inventory, but a review of records indicated that a cobalt-60 source had been
reported missing in 1970 (ORPS Report ALO--GEO-GJO-1992-0019). Another loss of source
accountability occurred on July 22, 1992, at a Hanford facility when a cesium-137
check source used for calibration of radiation detection instruments was discovered
missing. Facility personnel found the source several days later in a parking lot. The
source was damaged and reading 10,000 disintegrations per minute. A Radiation
Protection Technologist had used the source to demonstrate an equipment
malfunction in the parking lot and the source was not properly returned to its
container (ORPS Report RL--PNL-PNLBOPEM-1992-0008).
NS reported on several other occurrences involving improper control and disposal of
radioactive sources in OE Weekly Summary 93-06. One event involved the death of
several people in China when a worker found a cobalt-60 source while cleaning a well
in November 1992. In the following days, he and two members of his immediate
family died of radiation sickness. In a similar case in Brazil in 1987, four people died
and 240 absorbed high doses of the radioactive isotope cesium-137 when a group
of children discovered a glowing capsule in a scrap heap and began to play with it.
These events underscore the importance of the proper control of radioactive sources.
Storage areas must be clearly identified and access controlled. Additional information
associated with control of sources can be found in NRC Information Notice IN 90-47,
"Unplanned Radiation Exposures to Personnel Extremities Due to Improper Handling
of Highly Radioactive Sources."
4. LOW FLASHPOINT OF DIESEL FUEL OIL
On February 18, 1993, personnel at the Savannah River Replacement Tritium Facility
(RTF) determined that the flashpoint for the standby diesel generator fuel was below
expected administrative limits, causing a potentially combustible condition and making
the diesel generator inoperable. An analysis of the fuel oil indicated the flashpoint
was 70 degrees Fahrenheit, compared to the administrative limit of 125 degrees
Fahrenheit. Upon discovery, facility personnel locked the diesel out of service,
barricaded the diesel generator building, and set up a blower to force fresh air into the
building. Facility personnel had not determined the cause of the low flashpoint when
this OE Weekly Summary was prepared. They suspect that the off-site fuel delivery
service did not properly flush the tank prior to filling it with the diesel fuel scheduled
for delivery to the RTF facility. If the previous shipment had been at a lower
flashpoint, residual amounts may have contaminated the RTF shipment and lowered
the flashpoint. A low flashpoint means that the fuel could detonate early in the
compression cycle and potentially damage internal components of the diesel.
Prior to this event, facility personnel had several problems with the diesel fuel. On
February 2, 1993, facility personnel analyzed the diesel fuel in accordance with
facility Technical Safety Requirements and determined that the fuel exceeded
allowable limits for water content and bottom sediments. Workers drained the fuel
from the storage tank and ordered replacement fuel. On February 8, 1993, workers
refilled the storage tank and obtained samples of the fuel. The results of the analysis
indicated bottom sediment in excess of surveillance requirement limits. Facility
personnel drained several gallons from the bottom of the tank to flush the excess
sediment. Subsequent analysis indicated that the bottom sediments were within
surveillance requirement limits.
DOE facilities have reported many other problems involving diesel fuel. Most fuel
problems result from low usage rates and fuel degradation over time. The rate of
degradation depends on storage temperature and the quality of the fuel. Heat may
accelerate fuel degradation and cause condensate to form on the tank walls as the
tank experiences a daily thermal cycle. Fuel degradation produces particulate and
insoluble gum contaminants in the fuel. The particulate, gum, and condensate tend
to settle at the tank bottom creating a medium for organic growth at the fuel/water
interface. Anaerobic sulfate-reducing bacteria, fungus, and yeast can grow in two-
phase systems containing water and diesel fuel. Removing water and contaminants
from the tank bottom and limiting the amount of water and contaminants introduced
with new fuel is extremely important. A fuel maintenance and testing program can
control fuel quality resulting in increased reliability of the diesel. ASTM D-975,
"Standard Specification for Diesel Fuel Oils," and ASTM D-4057, "Standard Practice
for Manual Sampling of Petroleum and Petroleum Products," are two industry
standards often used to ensure the quality of diesel fuel.
NS previously discussed the importance of monitoring emergency diesel generator fuel
specifications in OE Weekly Summary 92-29. Additional information can be found
in NRC IE Circular 77-15, "Degradation of Fuel Oil Flow to the EDG," and IE
Information Notice 87-04, "Diesel Generator Fails Test Because of Degraded Fuel."
5. CAUTION REGARDING THE PACKAGING OF METALLIC URANIUM IN STEEL DRUMS
On March 3, 1993, NS received a letter from an incident investigation team at
Lawrence Livermore National Laboratory (LLNL) regarding packaging of metallic
uranium in steel drums. The team reviewed several incidents involving unexpected
chemical reactions in steel drums holding metallic uranium. The team concluded that
although the chemistry involved in the incident is well documented, the incidents and
their probable causes are not common knowledge at DOE facilities.
The primary incident investigated involved an event that occurred on July 13, 1992.
An LLNL technician attempted to open a 30-gallon steel drum containing about 600
kg of depleted uranium rods. After removing the clamping ring, the worker used a
hammer and punch to pry the lid from the drum. Suddenly, the lid flew about three
feet into the air, apparently as a result of a low-grade hydrogen/oxygen reaction.
Immediately, packaging material in the drum caught fire. The technician replaced the
drum lid in an attempt to extinguish the fire. Facility personnel placed the drum in an
overpack and transported the container to a secure location (ORPS Report SAN--LLNL-LLNL-
1992-0062).
Several weeks later, facility personnel pierced the drum to determine the composition
of the gas content. The analysis indicated 25 percent hydrogen and 75 percent
nitrogen. The team hypothesized that a uranium/water reaction had produced
uranium oxide, uranium hydride, and hydrogen gas in the drum. When the lid was
removed, oxygen reacted with the uranium hydride resulting in the hydrogen/oxygen
reaction and ignition of the fire in the packaging material.
The LLNL investigative team concluded that using vented containers to store and ship
uranium metal was more reliable than using sealed containers. The letter states that:
"Although the vent provides a pathway for moisture to enter the container, it allows
the oxygen content to remain normal - thus inhibiting the uranium/water reaction -
and allows any hydrogen to escape. If sealed containers are to be used, attention
should be paid to the nature of the gasket and the integrity of the seal it makes. Care
must be taken to ensure that no source of moisture exists in a well-sealed container
of uranium metal. This means no organic packing material." The letter further
recommends care when opening drums of uranium metal that have been in storage.
Moreover, workers should be particularly aware of tightly sealed lids because it is
possible that water has been present in the drum.
In February 1993, NS issued Safety Notice 93-1, Fire, Explosion, and High-Pressure
Hazards Associated with Waste Drums and Containers. Copies of Safety Notice 93-1
may be obtained by contacting the Nuclear Safety Information Center at 301-903-
5011.
Reference: D.H. Wood, S.A. Snowden, H.J. Howe, Jr., L.L. Thomas, D. W. Moon,
H. R. Gregg and P.E. Miller, A Caution Regarding the Packaging of Metallic Uranium
in Steel Drums, University of California, Lawrence Livermore Laboratory, Livermore,
California, 1993.
6. INCORRECT CIRCUIT BREAKER OPERATION CAUSES REACTOR TRIP BREAKERS TO
OPEN
On February 3, 1993, Instrument and Control (I&C) personnel at the Calvert Cliffs
commercial nuclear power plant in Maryland opened the wrong circuit breaker during
maintenance activities, inadvertently causing four of nine reactor trip breakers, which
are part of the plant's Reactor Protection System, to open. The reactor continued to
operate throughout the event.
I&C personnel were using an approved work order to replace a nuclear instrument
that was part of a Reactor Protection System (RPS) cabinet. The work order, which
had been reviewed by Quality Engineering and the Shift Supervisor, specified two
circuit breakers to be opened to isolate the nuclear instrument. However, when
workers opened the second breaker, they deenergized the entire RPS cabinet instead
of just the intended instrument causing the reactor trip breakers to open. Facility
personnel determined that the breaker specified in the work order was incorrect. The
work order described the breaker by its identification number and did not provide an
accurate description including the name of the breaker (NRC Event Number 25001).
This event illustrates the need for work control documents such as procedures and
work orders to include detailed information to help reduce potential errors in the work
to be performed. This event might have been avoided had both the name and number
of the circuit breakers been included in the work order. Additionally, the event is a
reminder that workers should be sufficiently trained and qualified, both technically
and in self-checking techniques, so they will be aware of and understand expected
plant responses when operating equipment.
7. OPERATIONAL SAFETY REQUIREMENT VIOLATION CAUSED BY FAILED TANK
LEVEL INSTRUMENTATION
On March 4, 1993, a level indicator transmitter (LIT) for a tank at the Hanford Tank
Farm (a group of underground tanks containing high level radioactive waste) failed,
and operators were unable to measure the level in the tank within a day, resulting in
a non-conformance of a facility Operational Safety Requirement (OSR) designed to
assure the integrity of the tank. The tank integrity was not in jeopardy during the
event because the OSR requires a minimum level of six inches when tank ventilation
is flowing to prevent implosion (tank level during the event was over 200 inches)
(ORPS Report RL--WHC-TANKFARM-1993-0027).
Facility personnel initially attempted to repair the failed LIT, the only one for the
associated tank, in time to meet the OSR requirement. When it became apparent that
this would not be likely, supervisors tried to manually measure the tank level using
a "zip cord" (an electrically charged cable calibrated to indicate when it contacts the
surface of the tank contents). However, logistics problems and difficulties in
constructing a satisfactory glovebox prevented them from obtaining the level
measurement in time to satisfy the OSR requirement.
Workers repaired the LIT, and facility personnel were conducting an investigation of
the occurrence to determine causes, lessons learned, and necessary corrective
actions. Although in this event the tank integrity was never at risk, a similar event
could have more serious consequences if a critical parameter was near its limit. This
event emphasizes the importance of ensuring that backup measures to ensure
compliance with safety limits are readily available and can be promptly implemented
when required.
8. INADVERTENT LIQUID WASTE TRANSFERS
On March 5, 1993, approximately 740 gallons of liquid waste were inadvertently
transferred from a receiver tank to a storage tank at the Hanford Tank Farm causing
a violation of facility LCOs regarding leak detection. The violated LCO required either
that remote monitoring for the leak detection systems be operable along the transfer
route or that continuous manual monitoring of the leak detectors take place. To meet
the LCO requirements, Westinghouse Hanford Company (WHC) assigned personnel
to continuously monitor local leak detection alarms during the transfer because the
alarms were not operating at manned remote locations.
Later, personnel left their stations when the transfer was suspended to troubleshoot
a failed air-operated valve. During troubleshooting and cycling of the air-operated
valve, an agitation pump used to suspend tank waste solids and act as the transfer
pump was left running to recirculate tank contents. The pump is normally run for
several hours prior to a transfer to ensure that waste solids are suspended and
transferred, and facility personnel allowed it to run while the transfer was suspended
hoping that the air-operated valve would be repaired quickly. Workers checked the
level in Tank 244-TX every four hours while the pump was running.
However, a manual isolation valve in the transfer route apparently suffered a
catastrophic failure between the time it was opened to start the transfer and when
it was closed to stop it. Facility personnel were unaware of the failure, which created
a flow path when the air-operated valve was cycled during troubleshooting. During
the inadvertent transfer, personnel were not in attendance at the local leak detection
alarms to meet LCO requirements.
There were no transfer line leaks during the transfer. Facility personnel repaired the
air-operated valve but did not repair the leaking valve because it was located in a
highly contaminated valve pit. To prevent recurrence of the event, facility personnel
implemented administrative controls requiring constant surveillance of local leak
detection alarms and tank levels whenever the agitation pump was running (ORPS
Report RL--WHC-TANKFARM-1993-0028).
In a similar event at the Savannah River FB-Line (a plutonium processing facility) in
December 1991, failure of a valve to remain fully closed caused an inadvertent waste
transfer. Facility personnel had closed the valve but the excessive size and weight
of the valve handle caused the valve to partially open. NS identified 16 other
occurrences involving inadvertent waste transfers at DOE facilities during 1991-1993.
Of these 16 occurrences, 12 were caused by improper procedure use or inadequate
procedure content.
These events illustrate the need for facility personnel to consider the possibility of
equipment failures and alternate flow paths whenever motive force for a transfer is
present. These events also demonstrate the importance of adequate procedural
content and use when conducting waste transfers. Procedures can be used to
provide guidance on identifying and monitoring alternative flowpaths.
9. RADIOACTIVE DISCHARGE FROM SHUTDOWN FACILITY
On February 12 and 13, 1993, an above-normal radioactive discharge occurred from
a ventilation stack at a facility at Sellafield, a nuclear fuel reprocessing and storage
site in England. The discharge coincided with work on a ventilation fan in B204,
which became more extensive when fan belts had to be replaced. Sellafield personnel
determined that the discharge was approximately 14 percent of the annual discharge
limit for the site, and the dose to the most exposed member of the general public was
.04 percent of the average dose to people in the United Kingdom (UK) from natural
background radiation. According to site personnel, there was no risk to the public or
the environment, and discharge levels were below Ministerial reporting levels.
The source of the discharge was B203, an adjoining ex-plutonium residue recovery
plant, which has been shut down since the 1980s and is being prepared for
decommissioning. Sellafield personnel are planning to install a new filtration system
in B203 as part of decommissioning preparations. Sellafield management indicated
that had such a system been in place the discharge would not have occurred.
Management also indicated that much safety analysis work would be completed
before decommissioning started in order to anticipate problems associated with
cleaning up old facilities and provide enhanced protection to the public and the
environment.
Sellafield management is also utilizing techniques similar to Total Quality Management
to improve the safety of facility operations. The Sellafield work force is being
consulted on proposed arrangements concerning health physics monitoring service on
the site. Management is examining all aspects of Sellafield operations, including
health physics monitoring to determine if they are being performed in the best
possible manner. These consultations and reviews have so far resulted in proposals
that emphasize the importance of maintaining safety standards while, at the same
time, allowing plant operators a greater role in determining how and in what order
work is performed (Sellafield Newsletter, Week Ending 2/23/93).
10. PERSONNEL INADVERTENTLY DISCONNECT FUEL HANDLING UNIT FROM HOOK
On March 4, 1993, in an irradiated fuel storage pool area in building CPP-603 at the
Idaho National Engineering Laboratory, a hook holding a bucket containing fuel scrap
inadvertently became disconnected causing a stoppage of operations and clearance
of personnel from the area. Building CPP-603 is used to receive, handle and store
irradiated fuel. Underwater buckets and racks contain Fuel Handling Units (FHUs) and
are used to store nuclear fuel in pools in a safe configuration to avoid nuclear
criticality. At the time of the occurrence, facility personnel were installing redundant
rigging to the fuel-scrap bucket (estimated weight - 30 pounds) in a pool. All 154
previous installations were on full-cluster FHUs weighing about 300 pounds.
Installation of redundant rigging was a corrective action in response to a prior event
where corrosion of carbon-steel yokes was observed (ORPS Reports ID--WINC-ICPP-1992-
0024). In the most recent event, a yoke supported the fuel-scrap bucket by the
bucket bail. The bucket bail hung from a yoke hook rigidly attached to the yoke. The
yoke hook became disconnected when rigging personnel attached the rigging
(consisting of stainless-steel cable, hook and turn-buckles) and pulled on the cable to
remove line slack. Because of the light weight of the bucket the riggers lifted it too
far, disconnecting it from the yoke hook and leaving the bucket suspended only by
the redundant rigging. The hook was found disconnected during an investigation
conducted after a foreman, who was performing a final configuration check using an
underwater video camera, noticed the bucket rotating. Had the bucket fallen, it
would have landed on the pool floor. Recovery of the bucket from that position
would be significant effort. But the bucket would not create a danger of a criticality
excursion because its contents are not highly reactive. The lesson of this event is the
need to account for all relevant aspects of the lifting and handling methodology (ORPS
Reports ID--WINC-ICPP-1993-0014).
Facility personnel report that there is no danger of a criticality excursion because they
maintain double contingency for criticality. They observe facility Technical Standard,
requiring a minimum edge-to-edge spacing of eight inches for FHUs. Additionally, the
fuel-scrap bucket is classified as non-highly reactive. This means it could be in
contact with another FHU and not create a criticality excursion.
A special procedure controlled the rigging operation. Abnormal and emergency
procedures were in place to control contingencies that might arise. Riggers were
trained and briefed prior to the job. Training included a walk through and mockup
practice. Personnel followed procedures.
Facility personnel have tentatively attributed the root cause of the problem to the
failure to recognize the differences involved in rigging lightweight versus full-cluster
FHUs. The special procedure, training, and job briefing did not account for handling
lightweight FHUs. Facility personnel plan to revise the special procedure, training,
and briefings to account for FHU weight differences. Also, they plan to implement
continuous underwater video monitoring for future redundant rigging operations.
Finally, a special recovery procedure will be implemented for the suspended bucket.
FINAL REPORTS - SUMMARIES
This section of the OE Weekly Summary discusses events that have been filed as Final reports
on the ORPS. These events contain new or additional lessons learned that may be of interest
to personnel within the DOE complex. The description of each event, its causes, and lessons
learned are edited from the original ORPS final report.
1. FAILURE OF REACTOR COARSE LEVEL INDICATION
Reference: ORPS Report SR--WSRC-REACK-1993-0025
On February 2, 1993, at the Savannah River K-Reactor, a tritium production facility,
personnel determined that one of the redundant reactor coarse (wide-range) level
indications failed. At the time of the occurrence, K-Reactor was shutdown for a
cooling tower outage. Operations personnel made the failure determination after a
review of a level reading recorded on the Control Room Roundsheet. The normal
reading for the indicator is 19.5 feet and the Roundsheet indicated a level greater
than 20 feet, i.e., off scale. Personnel initiated an investigation and verified correct
transmitter valve alignment, so they then initiated a work request to repair the
transmitter. Repair personnel found a calibration problem, calibrated the transmitter
and returned it to service on February 22. Nine hours elapsed from the time of the
initial Roundsheet recording of greater than 20 feet and the start of the investigation.
During the nine-hour period, a shift change occurred. The other level indication
capability remained operational while the failed transmitter was out of service. The
transmitter was a Republic Model P0331E.
The root and direct causes of the transmitter calibration failure were attributed to a
failed or defective part. The direct cause of the delay in finding and investigating the
failure was attributed to poor employee communications. Poor communications were
exhibited between and within shifts. The information was not communicated to the
Shift Manager on duty and, therefore, not communicated to the incoming Shift
Manager. A shift order was issued to the shifts emphasizing the importance of
communications, logkeeping, turnover briefing, and exercising an inquisitive attitude
towards abnormal data. This occurrence emphasized the importance of good
employee communications.
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 Ivon Fergus, Office of Nuclear Safety
at (301) 903-6364.
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.
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 Waste 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