Undetected Accumulation of Gas in Reactor Coolant SystemML031060539 |
Person / Time |
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Site: |
Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant ![Entergy icon.png](/w/images/7/79/Entergy_icon.png) |
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Issue date: |
05/24/1994 |
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From: |
Grimes B Office of Nuclear Reactor Regulation |
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To: |
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References |
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-nr IN-94-036, NUDOCS 9405190137 |
Download: ML031060539 (10) |
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Similar Documents at Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant |
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Category:NRC Information Notice
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Mclaughlin on NRC, Regarding NRC Information Notice 2006-13: Groundwater Contamination 2020-09-03 The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:Clinton]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:Fort Saint Vrain]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Atlantic Nuclear Power Plant]] </code>.
[Table view]The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:Clinton]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:Fort Saint Vrain]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Atlantic Nuclear Power Plant]] </code>. |
UNITED STATES P/-3Y NUCLEAR REGULATORY
COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 May 24, 1994 NRC INFORMATION
NOTICE 94-36: UNDETECTED
ACCUMULATION
OF GAS IN REACTOR COOLANT SYSTEM
Addressees
All holders of operating
licenses or construction
permits for nuclear power reactors.
Purpose
The U.S. Nuclear Regulatory
Commission (NRC) is issuing this information
notice to alert addressees
to problems that could result from unrecognized
evolution
and accumulation
of gas in reactor coolant system high points. It is expected that recipients
will review this information
for applicability
to their facilities
and consider actions, as appropriate, to avoid similar problems.
However, suggestions
contained
in this information
notice are not NRC requirements;
therefore, no specific action or written response is required.Description
of Circumstances
Sequoyah Unit I had been shut down in March 1993. In early September
1993, after the unit had been refueled, the reactor vessel was reassembled
and the reactor coolant system was degassed, filled, and vented. The reactor coolant system was then depressurized
to atmospheric
pressure.
One pressurizer
power-operated relief valve (PORV) was open and the reactor coolant system average temperature
was being maintained
at approximately
49C [120'F]. Nitrogen cover gas was being supplied to the volume control tank at approximately
239 kPa [20 psig] and reactor coolant was being circulated
by the charging system and the residual heat removal (RHR) system. The reactor vessel level indication
system (RVLIS) was functional
for a significant
portion of the event. Before this event, instrument
maintenance
stickers were placed on the RVLIS indicators
for other maintenance
work. Although the RVLIS information
was available, the operators
were not monitoring
this information
because it was not procedurally
required to be used in shutdown modes of operation.
Reactor coolant system inventory
was being monitored
using pressurizer
cold calibration
level indications.
On December 17, 1993, the operators
began to pressurize
the containment
to 191 kPa [13 psig] in order to perform a containment
integrated
leak rate test.As containment
pressure increased, the operators
noticed a decrease in pressurizer
water level and, over a period of time, added approximately
31,400 liters [8,300 gallons] of water to maintain the pressurizer
level. Licensee personnel
evaluated
this situation
and recognized
that gas was accumulating
in the reactor coolant system. However, they failed to recognize
the magnitude 9405190137 po\ fit JE ote qq-f3tn 9t1S EsoI'I'
- ..~ -IN 94-36 May 24, 1994 or cause of the problem. Three days later, as the containment
was being depressurized
upon completion
of the containment
leak test, the operators noted that approximately
the same amount of water had to be removed from the reactor coolant system to maintain the level. On December 21, 1993, on the basis of operators'
observations
of the changing coolant system Inventory during the containment
leak test, the reactor vessel head was vented. It was subsequently
vented several times to maintain appropriate
reactor vessel inventory
based on RYLIS information.
The reactor vessel gas voiding conditions
went undetected
from early September
1993, when the reactor coolant system was verified to be filled, until December 21, 1993, when the reactor head was vented.The gas evolution
resulted from the temperature
in the volume control tank being much lower than that normally expected. (This lower temperature
was due to unusually
low component
cooling water temperatures
and to a maintenance
problem with a cooling water valve that resulted in the reduction
of the heat sink temperature
in the letdown heat exchanger.)
The lower temperatures
increased
the solubility
of gas in the volume control tank water so that more gas was dissolved
in the water. This gas evolved when the water was transferred
to the reactor coolant system by the charging system and heated up in the reactor vessel.Further details concerning
this event are in NRC Inspection
Report No. 50-327;50-328/94-04.
Discussion
The licensee completed
a final evaluation
in January 1994 and determined
that during this event the reactor vessel water level had decreased
to slightly below the top of the hot leg, and that the steam generator
tubes were nearly empty. The reactor coolant system inventory
was being monitored
solely on the basis of pressurizer
level, which was not indicative
of the reactor vessel and steam generator
levels. Calculations
by the licensee indicated
that an equilibrium
had been reached during the event so that the water level was approximately
1.6 meters [5.25 feet] above the top of the core. Any additional
gas evolved in the reactor vessel would be expected to be vented through the hot leg and surge line to the pressurizer
and out through the open pressurizer
PORV.The reactor water level at which equilibrium
was established
at Sequoyah was sufficiently
high so as not to interfere
with reactor coolant flow through the RHR cooling system. However, at other plants, the equilibrium
level, which is related to pressurizer
surge line geometry and RHR suction line location, might be such that a similar event could interfere
with shutdown cooling.Another potential
safety concern is related to the capability
of the steam generators
to transfer heat from the reactor coolant to secondary
coolant. In the equilibrium
condition
at Sequoyah, the steam generator
tubes were almost empty during at least a portion of the duration of this event. During this
IN 94-36--JMay 24, 1994 period, the steam generators
were assumed to be available
as an alternate means for shutdown cooling. It is not clear that cooling through the steam generators
could have been established, if needed, especially
because the plant operators
were unaware that the tubes were empty.Several factors involving
licensee performance
contributed
to the delay in the identification
and evaluation
of this event. They included (1) lack of consideration
on the part of licensee personnel
with respect to compression
of gas in the system caused by containment
pressure transmitted
to the reactor coolant system water through the open pressurizer
PORV; (2) misunderstanding
by the operators
about the operability
of RVLIS; (3) failure to stop the containment
leak test when water level changes were first noted so that the situation
could have been adequately
evaluated;
(4) an apparent lack of thorough evaluation
of previously
published
information
on similar events.The event discussed
in this information
notice highlights
the potential
for gas evolution
and accumulation
in the reactor coolant system in locations
and quantities
that may not be evident to operators.
Changes in temperature
and pressure can have significant
effects on the solubility
of gas in water, especially
at or near atmospheric
pressure conditions.
During cold shutdown, this phenomenon
can permit significant
quantities
of cover gas to be dissolved in lower-temperature, higher-pressure
volumes such as the volume control tank and to evolve into a large gas bubble in the reactor vessel (a lower-pressure, higher-temperature
area). This phenomenon
can occur without a sudden change in pressurizer
level, which is the indicator
normally used by the operators
to monitor water inventory.
Use of available
instrumentation
in shutdown modes to monitor reactor vessel water level can provide detection
of unexpected
system conditions
when reduced vessel inventory
is not planned as well as in reduced inventory
evolutions.
On April 12, 1994, a similar gas accumulation
event was identified
at the Salem Generating
Station (Unit 1) shortly after it entered Mode 5 (cold shutdown)
operation.
Although this occurrence
did not involve amounts of gas accumulation
as large as in the Sequoyah event, many similarities
existed regarding
both the process of gas formation
and the lack of operator awareness of the abnormal condition.
In both events, reactor vessel level information
was or could have been made available
for prompt identification
of the problem.Related Generic Communications
Notice 93-12, "Off-Gassing
in Auxiliary
Feedwater System Raw Water Sources," discusses
similar solubility
considerations
related to air pockets in piping at the McGuire Nuclear Station.* NRC Information
Notice 87-46, "Undetected
Loss of Reactor Coolant," discusses
undetected
loss of reactor coolant inventory at North Anna Unit 1 resulting
from inadequate
use of available indications
and failure to perform mass inventory
balances.
-\ > <_IN 94-36 May 24, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact one of the technical
contacts listed below or the appropriate
Of ice of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
contacts:
R. Benedict, NRR (301) 504-1157 S. M. Shaeffer, RII (615) 842-8001 Attachment:
List of Recently Issued NRC Information
Notices
I At,.thment
IN 94-36 May 24, 1994 LIST OF RECENTLY ISSUED NRC INFORMATION
NOTICES Information
Date of Notice No. Subject Issuance Issued to 91-81, Supp. 1 94-35 94-34 94-33 93-53, Supp. 1 94-32 94-31 90-68, Supp. 1 94-30 Switchyard
Problems that Contribute
to Loss of Offsite Power NIOSH Respirator
User Notices, "Inadvertent
Separation
of the Mask-Mounted Regulator (MMR)from the Facepiece
on the Mine Safety Appliances (MSA)Company MMR Self-Contained
Breathing
Apparatus (SCBA)and Status Update Thermo-Lag
330-660 Flexi-Blanket
Ampacity Derating Concerns Capacitor
Failures in Westinghouse
Eagle 21 Plant Protection
Systems Effect of Hurricane Andrew on Turkey Point Nuclear Generating
Station and Lessons Learned Revised Seismic Hazard Estimates Potential
Failure of Wilco, Lexan-Type
HN-4-L Fire Hose Nozzles Stress Corrosion
Cracking of Reactor Coolant Pump Bolts Leaking Shutdown Cooling Isolation
Valves at Cooper Nuclear Station 05/19/94 05/16/94 05/13/94 05/09/94 04/29/94 04/29/94 04/14/94 04/14/94 04/12/94 All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors, and all licensed fuel facilities.
All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of 01 or CPs for pressurized
water reactors.All holders of OLs or CPs for nuclear power reactors.OL -Operating
License CP -Construction
Permit
IN 94-xx May xx, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact one of the technical
contacts listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
contacts: R. Benedict, NRR (301) 504-1157 S. M. Shaeffer, R11 (615) 842-8001 Attachment:
List of Recently Issued NRC Information
Notices*See Dnrvinim- concurrence
wBw _. _ .-1 _._OFFICE *OEAB:DORS
SMShaeffer
PCWen MLesser MFMejaclDATE 05/04/L94
05/05/94 05/05/94 05/05/94 05/05/94[*AC/SRXB:DSSA
D/DORS TECollins
MVirgilio
AChaffee AJKugler BKGrimes 05/06/94 05/09/94 05/09/94 05.12/94 / /94 DOCUMENT NAME: SLQGAbIN.KV1 NOTE: The PMs for Sequoyah (D. LaBarge) and Salem (J.informed of the development
of this information
reviewed the draft information
notice.Stone) have been notice and they have Peter Wen, 5/10/94 IN 94-xx May xx, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact the technical
contact listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
Contacts: R. Benedict, NRR (301) 504-1157 S. M. Shaeffer, RI!(615) 842-8001 Attachment:
List of Recently Issued NRC Information
Notices*See previous concurrence
OFFICE *OEAB:DORS
SMShaeffer
PCWen MLesser MFMejac DATE 05/04/94 05/05/94 05/05/94 05/05/94 05/05/94*AC/SRXB:DSSA
D/DORS TECollins
8EXI MVirgilio
I AChaffee AJKugler BKGrimes 05/06/94 1 05/09/94 05/09/94 05/12/94 / /94 nnlflMFNT
IAMr. eCnveCTit
niti.-- -- I ia11 I EAdIL* .JLA(Un4.1 n .* r A NOTE: The PMs for Sequoyah (D. LaBarge) and Salem (J.informed of the development
of this information
reviewed the draft information
notice.Stone) have been notice and they have Peter Wen, 5/10/94 IN 94-xx May xx, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact the technical
contact listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
Contacts: R. Benedict, NRR (301) 504-1157 S. M. Shaeffer, R11 (615) 842-8001 Attachment:
List of Recently Issued NRC Information
Notices See previous concurrence
OFFICE l *OEAB:DORS
l *SC/DRP:RII
SMShaeffer
PCWen MLesser MFMejac DATE 1 05/04/94 1_05/05/94
1 05/05/94 _ 05/05/94 1 05/05/94*AC/SRXB:DSSA
AC/OGCB:DORS
D/DORS TECollins
MVirgilio
AChaffee AJKugler i(: BKGrimes 05/06/94 = 05/09/94 05/09/94 5/1V94 / /94 DOCUMENT NAME: SEQGASIN.RV1 NOTE: The PMs for Sequoyah (D. LaBarge) and Salem (J.informed of the development
of this information
reviewed the draft information
notice.Stone) have been notice and they have Peter Wen, 5/10/94 IN 94-xx May xx, 1994 This information
notice requires no specific action or writttten
response.you have any questions
about the information
in this notice, please contact the technical
contact listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.If Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
Contacts: R. Benedict, NRR (301) 504-1157 S. M. Shaeffer, RII (615) 842-8001 Attachment:
List of Recently Issued NRC Information
Notices OFFICE IOEABDOR5 DRP:RIIpcyJ
OGCB_ _ _ SC/DRP:RI
TECH ED NAME Benedict 'MShaeffer
PCWen Lesser DATE </A/94 5 /5/94 5 / 94/94 5//94 5 / 5/94 AC/SRXB:DSSA , AD/DSSA j C/OEAB:DORS
AC/OGCB:DORS
D/DORS TEColli MVirgil ' A2 fe AJKugler BKGrimes_____94 /$\/94 /947/94 94 / /94 UULUMtN I NAML: x 01 I J//q btbAbI1 N.KV1 jp'A4Mi: THE R& FR FoY(AH (-. LAMRPE) Azb 6MPA (j. )ROeia^ SoF'E Deospwt oF Ttts um. waIce ARD'NW ME .F) T"E JPV O D0e bWf ^ .&4-vhiw S/o/oA4.
IN 94-36 May 24, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact one of the technical
contacts listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.orig /s/'d by BKGrimes Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
contacts: R. Benedict, NRR (301) 504-1157 S. M. Shaeffer, R11 (615) 842-8001 Attachment:
List of Recently Issued NRC Information
Notices*See Previous concurrence
E OFFICE *OEAB:DORS
SMShaeffer
PCWen MLesser MFMejac DATE j05/04/94
05/05/94 05/05/94 05/05/94 05/05/94l*AC/SRXB:DSSA
RS*TECollins
MVirgilio
AChaffee AJKugler Iv _s 05/06/94 05/09/94 i 05/09/94 05/12/4 05//f/94 UuUMtrII NAM t: vq-io. IN NOTE: The PMs for Sequoyah (D. LaBarge) and Salem (J.informed of the development
of this information
reviewed the draft information
notice.Stone) have been notice and they have Peter Wen, 5/10/94
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list | - Information Notice 1994-01, Turbine Blade Failures Caused by Torsional Excitation from Electrical System Disturbance (7 January 1994)
- Information Notice 1994-02, Inoperability of General Electric Magne-Blast Breaker Because of Misalignment of Close-Latch Spring (7 January 1994)
- Information Notice 1994-03, Deficiencies Identified During Service Water System Operational Performance Inspections (11 January 1994, Topic: Biofouling)
- Information Notice 1994-04, Digital Integrated Circuit Sockets with Intermittent Contact (14 January 1994)
- Information Notice 1994-05, Potential Failure of Steam Generator Tubes with Kinetically Welded Sleeves (19 January 1994, Topic: Stress corrosion cracking)
- Information Notice 1994-06, Potential Failure of Long-Term Emergency Nitrogen Supply for the Automatic Depressurization System Valves (28 January 1994)
- Information Notice 1994-07, Solubility Criteria for Liquid Effluent Releases to Sanitary Sewerage Under the Revised 10 CFR Part 20 (28 January 1994)
- Information Notice 1994-08, Potential for Surveillance Testing to Fail to Detect an Inoperable Main Steam Isolation Valve (1 February 1994)
- Information Notice 1994-09, Release of Patients with Residual Radioactivity from Medical Treatment & Control of Areas Due to Presence of Patients Containing Radioactivity Following Implementation of Revised 10 CFR Part 20 (3 February 1994, Topic: Brachytherapy)
- Information Notice 1994-10, Failure of Motor-Operated Valve Electric Power Train Due to Sheared or Dislodged Motor Pinion Gear Key (4 February 1994)
- Information Notice 1994-11, Turbine Overspeed and Reactor Cooldown During Shutdown Evolution (8 February 1994)
- Information Notice 1994-12, Insights Gained from Resolving Generic Issue 57: Effects of Fire Protection System Actuation on Safety-Related Equipment (9 February 1994, Topic: Overspeed trip)
- Information Notice 1994-13, Unanticipated and Unintended Movement of Fuel Assemblies and Other Components Due to Improper Operation of Refueling Equipment (28 June 1994)
- Information Notice 1994-14, Failure to Implement Requirements for Biennial Medical Examinations and Notification to the NRC of Changes in Licensed Operator Medical Conditions (24 February 1994)
- Information Notice 1994-15, Radiation Exposures During an Event Involving a Fixed Nuclear Gauge (2 March 1994)
- Information Notice 1994-16, Recent Incidents Resulting in Offsite Contamination (3 March 1994)
- Information Notice 1994-17, Strontium-90 Eye Applicators: Submission of Quality Management Plan (QMP), Calibration, and Use (11 March 1994, Topic: Brachytherapy)
- Information Notice 1994-17, Strontium-90 Eye Applicators: Submission of Quality Management Plan (Qmp), Calibration, and Use (11 March 1994, Topic: Brachytherapy)
- Information Notice 1994-18, Accuracy of Motor-Operated Valve Diagnostic Equipment (Responses to Supplement 5 to Generic Letter 89-10) (16 March 1994)
- Information Notice 1994-19, Emergency Diesel Gemerator Vulnerability to Failure from Cold Fuel Oil (16 March 1994)
- Information Notice 1994-20, Common-Cause Failures Due to Inadequate Design Control and Dedication (17 March 1994)
- Information Notice 1994-21, Regulatory Requirements When No Operations Are Being Performed (18 March 1994)
- Information Notice 1994-22, Fire Endurance & Ampacity Derating Test Results for 3-Hour Fire-Rated Thermo-Lag 330-1 Fire Barriers (16 March 1994, Topic: Fire Barrier)
- Information Notice 1994-23, Guidance to Hazardous, Radioactive and Mixed Waste Generators on the Elements of a Waste Minimization Program (25 March 1994, Topic: Fire Barrier)
- Information Notice 1994-24, Inadequate Maintenance of Uninterruptible Power Supplies & Inverters (24 March 1994, Topic: Safe Shutdown, Fire Barrier)
- Information Notice 1994-25, Failure of Containment Spray Header Valve to Open Due to Excessive Pressure from Inertial Effects of Water (15 March 1994, Topic: Fire Barrier)
- Information Notice 1994-26, Personnel Hazards and Other Problems from Smoldering Fire-Retardant Material in the Drywell of a Boiling-Water Reactor (28 March 1994, Topic: Fire Barrier)
- Information Notice 1994-27, Facility Operating Concerns Resulting from Local Area Flooding (31 March 1994, Topic: Fire Barrier)
- Information Notice 1994-28, Potential Problems with Fire-Barrier Penetration Seals (5 April 1994, Topic: Fire Barrier)
- Information Notice 1994-29, Charging Pump Trip During a Loss-of-Coolant Event Caused by Low Suction Pressure (11 April 1994, Topic: Boric Acid)
- Information Notice 1994-30, Leaking Shutdown Cooling Isolation Valves at Cooper Nuclear Station (19 August 1994, Topic: Fire Barrier)
- Information Notice 1994-31, Potential Failure of Wilco, Lexan-Type HN-4-L Fire Hose Nozzles (14 April 1994, Topic: Hydrostatic)
- Information Notice 1994-32, Revised Seismic Estimates (29 April 1994, Topic: Earthquake)
- Information Notice 1994-33, Capacitor Failures in Westinghouse Eagle 21 Plant Protection Systems (9 May 1994, Topic: Stress corrosion cracking)
- Information Notice 1994-34, Thermo-LAG 330-660 Flexi-Blanket Ampacity Derating Concerns (13 May 1994, Topic: Fire Barrier)
- Information Notice 1994-35, Niosh Respirator User Notices, Inadvertent Separation of the Mask-Mounted Regulator(Mmr) from the Facepiece on the Mine Safety Appliances (16 May 1994)
- Information Notice 1994-35, Niosh Respirator User Notices, Inadvertent Separation of the Mask-Mounted Regulator(MMR) from the Facepiece on the Mine Safety Appliances (16 May 1994)
- Information Notice 1994-36, Undetected Accumulation of Gas in Reactor Coolant System (24 May 1994, Topic: Reactor Vessel Water Level, Stress corrosion cracking, Integrated leak rate test)
- Information Notice 1994-37, Misadministration Caused by a Bent Interstitial Needle During Brachytherapy Procedure (27 May 1994, Topic: Brachytherapy)
- Information Notice 1994-38, Results of Special NRC Inspection at Dresden Nuclear Power Station, Unit 1 Following Rupture of Service Water Inside Containment (27 May 1994)
- Information Notice 1994-39, Identified Problems in Gamma Stereotactic Radiosurgery (31 May 1994)
- Information Notice 1994-40, Failure of a Rod Control Cluster Assembly to Fully Insert Following a Reactor Trip at Braidwood, Unit 2 (26 May 1994)
- Information Notice 1994-41, Problems with General Electric Type Cr124 Overload Relay Ambient Compensation (7 June 1994)
- Information Notice 1994-41, Problems with General Electric Type CR124 Overload Relay Ambient Compensation (7 June 1994)
- Information Notice 1994-42, Cracking in the Lower Region of the Core Shroud in Boiling-Water Reactors (7 June 1994)
- Information Notice 1994-43, Determination of Primary-to-Secondary Steam Generator Leak Rate (10 June 1994, Topic: Grab sample)
- Information Notice 1994-44, Main Steam Isolation Valve Failure to Close on Demand Because of Inadequate Maintenance and Testing (16 June 1994)
- Information Notice 1994-44, Main Steam Isolation Valve Failure to Close on Demand because of Inadequate Maintenance and Testing (16 June 1994)
- Information Notice 1994-45, Potential Common-Mode Failure Mechanism for Large Vertical Pumps (17 June 1994, Topic: Biofouling)
- Information Notice 1994-46, Nonconservative Reactor Coolant System Leakage Calculation (20 June 1994)
... further results |
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