Potential for Loss of Remote Shutdown Capability During a Control Room FireML031200481 |
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 |
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Issue date: |
02/28/1992 |
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From: |
Rossi C Office of Nuclear Reactor Regulation |
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To: |
|
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References |
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IN-92-018, NUDOCS 9202240025 |
Download: ML031200481 (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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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
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 February 28, 1992 NRC INFORMATION NOTICE 92-18: POTENTIAL FOR LOSS OF REMOTE SHUTDOWN
CAPABILITY DURING A CONTROL ROOM FIRE
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 conditions found at several reactors that could
result in the loss of capability to maintain the reactor in a safe shutdown
condition in the unlikely event that a control room fire forced reactor
operators to evacuate the control room. It is expected that recipients
will review the 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
On July 26, 1991, the Washington Public Power Supply System, the licensee for
Unit 2 at the Washington Nuclear Plant.(WNP-2), discovered an unanalyzed
condition regarding fire protection and the safe shutdown capability for the
plant. The licensee found that a fire in the control room could cause hot
shorts, i.e. short circuits between control wiring and power sources, for
certain motor-operated valves (MOVs) needed to shut the reactor down and to
maintain it in a safe shutdown condition. If a fire in the control room
forces reactor operators to leave the control room, these MOVs can be
operated from the remote/alternate shutdown panel. However, hot shorts, combined with the absence of thermal overload protection, could cause valve
damage before the operator shifted control of the valves to the remote/
alternate shutdown panel.
Thermal overload protection is absent for some valves at WNP-2. This configu- ration exists to ensure that the thermal overload protection does not prevent
MOYs from performing their safety-related functions during an accident. As a
result, the thermal overload protection is configured to be either
continuously bypassed or bypassed only during an accident. Regulatory Guide
(RG) 1.106, Revision 1, 'Thermal Overload Protection for Electric Motors on
Motor-Operated Valves,* provides guidance in this area.
Figure 1 of Attachment 1 shows the control circuitry for-MOVs in a conceptual
manner, and the figure includes the relay coils which operate the contactors
9202240025 PDR 'LT T 0r% 9L-co0 I
Abbe- I/
IN 92-18 February 28, 1992 in the power circuitry for the motors. Figure 2 provides an example of the
manner in which the motor of an MOV that is closed can be energized and
damaged by a hot short if its overload protection is bypassed. The hot short
bypasses the push button that is normally used to close the MOV and thus
provides power to the relay coil, which closes those contactors that provide
power to drive the motor in the closed direction. Power will not be
disconnected from the motor although it is stalled, because the same hot
short bypasses the torque switch. With the motor stalled, current and torque
are abnormally high, possibly causing the motor windings to fail and possibly
causing mechanical damage to the valve. This mechanical damage may be suffi- cient to prevent reactor operators from manually operating the valve. A
similar problem can occur for MOYs that are open (see Figure 3). Shorts to
other sources of power can also cause failure of MOVs.
The licensee for WNP-2 determined that up to .15 MOVs in the residual heat
removal system might be adversely affected in this scenario. After
identifying the problem while the reactor was shut down, the-licensee
notified the NRC Operations Center and took corrective action. After con- ducting an initial analysis and before restarting the reactor, the licensee
rewired the control circuitry for the MOVs so that the torque and limit
switches in the valve operators are now located electrically between the
control room, the remote or alternate shutdown panel, and the motor control
center. Figure 4 is a diagram of the concept. Figures 5 and 6 show how hot
shorts can still cause the modified control circuitry to open or close the
MOYs. However, now the torque and limit switches are not bypassed by the hot
short, and the MOVs are protected from damage.
On November 20, 1991, the Pennsylvania Power and Light Company, licensee for
the Susquehanna Steam Electric Station, learned of the problem at WNP-2, determined that a similar condition existed for both units at the Susquehanna
Steam Electric Station, and notified the NRC Operations Center. Later, the
licensee stated that 37 MOVs which would be required to place the plant in a
safe shutdown condition could possibly be damaged by hot shorts occurring
during a fire in the control room. One of the MOVs is a reactor recirculation
suction valve, 15 are in the reactor core isolation cooling system, 16 are in
the residual heat removal system, and 5 are in the service water system.
On December 10, 1991, Northern States Power Company also found a similar
condition at the Monticello Nuclear Generating Plant.
Discussion
In RG 1.106, Revision 1, the staff stated that if thermal overload protection
devices are bypassed, it is important to ensure that the bypassing does not
result in Jeopardizing the completion of the safety function or in degrading
other safety systems because of any sustained abnormal circuit currents that
may be present.
IN 92-18 February 28, 1992 and valve operators are
When thermal overload protection devices are bypassed in sustained abnormal
wired as shown in Figure 1, hot shorts can result devices are not
circuit currents. Even if thermal overload protection
MOYs by tripping the thermal
bypassed, hot shorts can cause loss of power to of the motors for excessive
overload protection devices because of the demand capability to
current. In this case, hot shorts impair the it licensee's
in a safe shutdown condition.
efficiently shut its plant down and maintain operators to put them between
Rewiring the control circuitry for the valve
panel, and the motor
the control room, the remote or alternate shutdownand limit switches by hot
control centers prevents bypassing of the torque
shorts in the control room.
Related-Generic Communications
86-10, "Implementation of
The staff addressed hot shorts in Generic Letter 5.3.1.
Fire Protection Requirements," Enclosure 2, Section
or written response. If
This information notice requires no specific action notice, please contact
this
you have any question about the information inthe appropriate Office of
one of the technical contacts listed below or
Nuclear Reactor Regulation (NRR) project manager.
.Rosir Dere~recto=r!
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical contacts: James E. Knight, NRR
(301) 504-3264 Roger W. Woodruff, NRR
(301) 504-1152 Attachments:
for MOYs"
1. Figure 1, "Conceptual Control CircuitryWhile
Figure 2, "Postulated Short Occurring an MOV is Closed"
Figure 3, "Postulated Short Occurring While an MOV is Open"
Figure 4, "Conceptual Modification of Control Circuitry for MOYs"
Modified Control
Figure 5, "Postulated Short Occurring While an MOV with
Circuitry is Closed"
with Modified Control
Figure 6, "Postulated Short Occurring While an MOv
Circuitry is Open"
2. List of Recently Issued NRC Information Notices
Attachment 1 IN 92-18 February 28, 1992 LEGEND
CONTACT
ACTUATION POI NTS
CR CONTROL ROOM LO
..
MCC MOTOR CONTROL CENTER
a LC
VO VALVE OPERATOR
MC RELAY COIL - CLOSE VALVE
MO RELAY COIL - OPEN VALVE I I I I III I 1 --
OPEN VALVE STROKE CLOSED
C PUSH BUTTON - CLOSE VALVE
0 PUSH BUTTON - OPEN VALVE
LC LIMIT SVITCH - CLOSE VALVE
- THE LINES INDICATE THAT THE SWITCH
CONTACT
S
LO LIMIT SWITCH - OPEN VALVE ARE CLOSED. THE POINTS INDICATE THE VALVE
T TORQUE SWITCH POSITIONS WHERE THE SWITCH
CONTACT
S OPEN AND.
0 GREEN LMP CLOSE. FOR THE TORQUE SWITCH, THE
CONTACT
S
R RED LAIP ARE ACTUATED BY THE POSITION OF THE VALVE
MI5K AT MID STROKE AND BY THE PRESET TORQUE
AT THE END OF THE CLOSING STROKE.
FIGURE 1. CONCEPTUAL CONTROL CIRCUITRY FOR MOVs
I
Attachment 1 IN 92-18 February 28, 1992 LEGEND
CONTACT
ACTUATION POINTS *
CR CONTROL ROOM LO a
RSP REMOTE SHUTDOWN PANEL -. T
MCC MOTOR CONTROL CENTER
LC ___
VO VALVE OPERATOR
mC RELAY COIL - CLOSE VALVE
I I I I I l.
MO RELAY COIL - OPEN VALVE
OPEN VALVE STROKE
I I
C PUSH BUTTON - CLOSE VALVE 'CLOSED
0 PUSH BUTTON - OPEN-VALVE
LC LIMIT SWITCH - CLOSE VALVE
- THE LINES INDICATE THAT THE SWITCH
CONTACT
S
LO LIMIT SWITCH - OPEN VALVE ARE CLOSED. THE POINTS INDICATE THE VALVE
T TORQUE SWITCH POSITIONS WHERE THE SWITCH
CONTACT
S OPEN AND
0 GREEN LAMP CLOSE. FOR THE TORQUE SWITCH. THE
CONTACT
S
R RED LAMP ARE ACTUATED BY THE POSITION OF THE VALVE
S HOT SHORT DISK AT MID STROKE AND BY THE PRESET TORQUE
AT THE END OF THE CLOSING STROKE.
F I GURE 2. POSTULATED SHORT OCCUR I NG WH I LE AN MOV I S CLOSED
I
Attachment 1 IN 92-18 February 28, 1992 LEGEND
CONTACT
ACTUATION POINTS -
LO
CR CONTROL ROOM T
MCC MOTOR CONTROL CENTER LC
VO VALVE OPERATOR
MC RELAY COIL - CLOSE VALVE I I I I I -1 I I I I
MO RELAY COIL - OPEN VALVE OPEN VALVE STROKE CLOSED
C PUSH BUTTON - CLOSE VALVE
0 PUSH BUTTON - OPEN VALVE
LC LIMIT SWITCH - CLOSE VALVE X THE LINES INDICATE THAT THE SWITCH
CONTACT
S
LO LIMIT SWITCH - OPEN VALVE ARE CLOSED. THE POINTS INDICATE THE VALVE
T TORQUE SWITCH POSITIONS WHERE THE SWITCH
CONTACT
S OPEN AND
0 GREEN LAMP CLOSE. FOR THE TOROUE SWITCH. THE
CONTACT
S
RED LAMP ARE ACTUATED BY THE POSITION OF THE VALVE
R
S HOT SHORT OtSK AT MID STROKE AND By THE PRESET TORGUE
AT THE END OF THE CLOSING STROKE.
FIGURE 3. POSTULATED SHORT OCCURRING WHILE AN MOV IS OPEN
Attachment 1 IN 92-18 February 28, 1992 LEGEND
CONTACT
ACTUATION POINTS '
CR CONTROL ROOM LO
MCC MOTOR CONTROL CENTER
VO VALVE OPERATOR LC
mC RELAY COIL - CLOSE VALVE p
MO RELAY COIL - OPEN VALVE I I I I I u I
.
I
.
I I
.
C PUSH BUTTON - CLOSE VALVE OPEN VALVE STROKE CLOSED
0 PUSH BUTTON - OPEN VALVE
LC LIMIT SWITCH - CLOSE VALVE
- THE LINES INDICATE THAT THE SWITCH
CONTACT
S
LO LIMIT SWITCH - OPEN VALVE ARE CLOSED. THE POINTS INDICATE THE VALVE
T TORQUE SWITCH POSITIONS WHERE THE SWITCH
CONTACT
S OPEN AND
0 GREEN LAMP CLOSE. FOR THE TORQUE SWITCH. THE
CONTACT
S
R RED LAM ARE ACTUATED BY THE POSITION OF THE VALVE
DISK AT MID STROKE AND BY THE PRESET TORQUE
AT THE END OF THE CLOSING STROKE.
FIGURE 4. CONCEPTUAL MODIFICATION OF.CONTROL CIRCUITRY FOR MOVs
Attachment 1 IN 92-18 February 28, 1992 LEGEND
CONTACT
ACTUATION POINTS 6
CR CONTROL ROOM LO
RSP REMOTE SHUTDOWN PANEL T
MCC MOTOR CONTROL CENTER
LC
VO VALVE OPERATOR
Mc RELAY COIL - CLOSE VALVE r
l l. l. l
MO RELAY COIL - OPEN VALVE
lI I I I I
I I I I
OPEN VALVE STROKE CLOSED
C PUSH eUTTON - CLOSE VALVE
0 PUSH BUTTON - OPEN VALVE
LC LIMIT SVITCH - CLOSE VALVE
- THE LINES INDICATE THAT THE SWITCH
CONTACT
S
LO LIMIT SWITCH - OPEN VALVE ARE CLOSED. THE POINTS INDICATE THE VALVE
T TORQUE SWITCH POSITIONS WHERE THE SWITCH
CONTACT
S OPEN AND
G GREEN LAMP CLOSE. FOR THE TORQUE SWITCH, THE
CONTACT
S
R RED LAMP ARE ACTUATED BY THE POSITION OF THE VALVE
S HOT SHORT DISK AT MID STROKE AND BY THE PRESET TORQUE
AT THE END OF THE CLOSING STROKE.
I
FIGURE 5. POSTULATED SHORT OCCURRINO WHILE AN MOV WITH
MODIFIED CONTROL CIRCUITRY IS CLOSED
Attachment 1 IN 92-18 February 28, 1992 LEGEND
CONTACT
ACTUAT I ON PO INTS *
LO
CR CONTROL ROOM
RSP REUOTE SHUTDOWN PANEL T
MCC MOTOR CONTROL CENTER LC
VO VALVE OPERATOR
MC RELAY COIL - CLOSE VALVE . I
. I
. I
. I II
. I
I I
I
I
C S
I
' VII I
MO RELAY COIL - OPEN VALVE OPEN VALVE STRC0KE CLOSED
C PUSH BUTTON - CLOSE VALVE
0 PUSH BUTTON - OPEN VALVE
LC LIMIT SWITCH - CLOSE VALVE U THE LINES INDICATE THAT THE SWITCH
CONTACT
S
LO LIMIT SWITCH - OPEN VALVE ARE CLOSED. THE POINTS INDICATE THE VALVE
T TOROUE SWITCH POS IT I ONS WHERE THE SW I TCH
CONTACT
S OPEN AND
0 GREEN LAMP CLOSE. FOR THE TORQUE SWITCH, THE
CONTACT
S
R RED LAMP ARE ACTUATED BY THE POSITION OF THE VALVE
S HOT SHORT DISK AT MID STROKE AND BY THE PRESET TORQUE
AT THE END OF THE CLOS ING STROKE.
FIGURE B. POSTULATED SHORT OCCURR INO WHILE AN MOV WITH
MODIFIED CONTROL CIRCUITRY IS OPEN
I
Attachment 2 IN 92-18 February 28, 1992 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information Date of
Notice No. Subject Issuance Issued to
92-17 NRC Inspections of Pro- 02/26/92 All holders of OLs or CPs
grams being Developed at for nuclear power reactors.
Nuclear Power Plants in
Response to Generic
Letter 89-10
92-16 Loss of Flow from the 02/25/92 All holders of OLs or CPs
Residual Heat Removal for nuclear power reactors.
Pump during Refueling
Cavity Draindown
92-15 Failure of Primary System 02/24/92 All holders of OLs or CPs
Compression Fitting for nuclear power reactors.
92-14 Uranium Oxide Fires at Fuel 02/21/92 All fuel cycle and uranium
Cycle Facilities fuel research and development
licensees.
92-02, Relap5/Mod3 Computer Code 02/18/92 All holders of OLs or CPs
Supp. 1 Error Associated with the for nuclear power reactors.
Conservation of Energy
Equation
92-13 Inadequate Control Over 02/18/92 All holders of OLs or CPs
Vehicular Traffic at for nuclear power reactors.
Nuclear Power Plant Sites
92-12 Effects of Cable Leakage 02/10/92 All holders of OLs or CPs
Currents on Instrument for nuclear power reactors.
Settings and Indications
92-11 Soil and Water Contamina- 02/05/92 All uranium fuel fabrica- tion at Fuel Cycle Facil- tion and conversion facil- ities ities.
OL = Operating License
CP = Construction Permit
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list | - Information Notice 1992-01, Cable Damage Caused by Inadequate Cable Installation Procedures and Controls (3 January 1992, Topic: Overspeed)
- Information Notice 1992-02, Relap5/MOD3 Computer Code Error Associated with the Conservation of Energy Equation (3 January 1992, Topic: Overspeed)
- Information Notice 1992-02, Relap5/Mod3 Computer Code Error Associated with the Conservation of Energy Equation (3 January 1992)
- Information Notice 1992-03, Remote Trip Function Failures in General Electric F-Frame Molded-Case Circuit Breakers (6 January 1992, Topic: Overspeed trip)
- Information Notice 1992-04, Potter and Brumfield Model Mdr Rotary Relay Failures (6 January 1992, Topic: Probabilistic Risk Assessment, Commercial Grade, Overspeed trip)
- Information Notice 1992-04, Potter and Brumfield Model MDR Rotary Relay Failures (6 January 1992, Topic: Probabilistic Risk Assessment, Commercial Grade)
- Information Notice 1992-05, Potential Coil Insulations Breakdown in Abs RXMH2 Relays (8 January 1992, Topic: Commercial Grade, Overspeed trip)
- Information Notice 1992-05, Potential Coil Insulations Breakdown in Abs Rxmh2 Relays (8 January 1992, Topic: Commercial Grade)
- Information Notice 1992-05, Potential Coil Insulations Breakdown in ABS RXMH2 Relays (8 January 1992, Topic: Commercial Grade)
- Information Notice 1992-06, Reliability of ATWS Mitigation System and Other NRC Required Equipment Not Controlled by Plant Technical Specifications (15 January 1992)
- Information Notice 1992-06, Reliability of ATWS Mitigation System and Other NRC Required Equipment not Controlled by Plant Technical Specifications (15 January 1992)
- Information Notice 1992-07, Rapid Flow-induced Erosion/Corrosion of Feedwater Piping (9 January 1992)
- Information Notice 1992-08, Revised Protective Action Guidance for Nuclear Incidents (23 January 1992)
- Information Notice 1992-09, Overloading and Subsequent Lock Out of Electrical Buses During Accident Conditions (30 January 1992)
- Information Notice 1992-10, Brachytherapy Incidents Involving Iridium-192 Wire Used in Endobronchial Treatments (31 January 1992, Topic: Brachytherapy)
- Information Notice 1992-10, Brachytherapy Incidents Involving Iridium-192 Wire used in Endobronchial Treatments (31 January 1992, Topic: Brachytherapy)
- Information Notice 1992-11, Soil and Water Contamination at Fuel Cycle Facilities (5 February 1992, Topic: Brachytherapy)
- Information Notice 1992-12, Effects of Cable Leakage Currents on Instrument Settings and Indications (10 February 1992, Topic: Brachytherapy)
- Information Notice 1992-13, Inadequate Control Over Vehicular Traffic at Nuclear Power Plant Sites (18 February 1992, Topic: Brachytherapy)
- Information Notice 1992-14, Uranium Oxide Fires at Fuel Cycle Facilities (21 February 1992, Topic: Brachytherapy)
- Information Notice 1992-15, Failure of Primary Systems Compression Fitting (24 February 1992, Topic: Unidentified leakage)
- Information Notice 1992-16, Loss of Flow from the Residual Heat Removal Pump During Refueling Cavity Draindown (25 February 1992, Topic: Reactor Vessel Water Level, Temporary Modification, Brachytherapy)
- Information Notice 1992-17, NRC Inspections of Programs Being Developed at Nuclear Power Plants in Response to Generic Letter 89-10 (26 February 1992, Topic: Stroke time)
- Information Notice 1992-18, Potential for Loss of Remote Shutdown Capability During a Control Room Fire (28 February 1992, Topic: Hot Short, Safe Shutdown)
- Information Notice 1992-19, Misapplication of Potter and Brumfield Mdr Rotary Relays (2 March 1992)
- Information Notice 1992-19, Misapplication of Potter and Brumfield MDR Rotary Relays (2 March 1992)
- Information Notice 1992-20, Inadequate Local Leak Rate Testing (3 March 1992, Topic: Local Leak Rate Testing)
- Information Notice 1992-21, Spent Fuel Pool Reactivity Calculations (24 March 1992)
- Information Notice 1992-23, Results of Validation Testing of Motor-Operated Valve Diagnostic Equipment (27 March 1992)
- Information Notice 1992-24, Distributor Modification to Certain Commercial-Grade Agastat Electrical Relays (30 March 1992)
- Information Notice 1992-25, Pressure Locking of Motor-Operated Flexible Wedge Gate Valves (2 April 1992, Topic: Stroke time, Hydrostatic)
- Information Notice 1992-27, Thermally Induced Accelerated Aging and Failure of ITE/Gould A.C. Relays used in Safety-Related Applications (3 April 1992, Topic: Commercial Grade)
- Information Notice 1992-27, Thermally Induced Accelerated Aging and Failure of Ite/Gould A.C. Relays Used in Safety-Related Applications (3 April 1992, Topic: Commercial Grade)
- Information Notice 1992-28, Inadequate Fire Suppression System Testing (8 April 1992, Topic: Safe Shutdown)
- Information Notice 1992-29, Potential Breaker Miscoordination Caused by Instantaneous Trip Circuitry (17 April 1992)
- Information Notice 1992-30, Falsification of Plant Records (23 April 1992)
- Information Notice 1992-31, Electrical Connection Problem in Johnson Yokogawa Corporation YS-80 Programmable Indicating Controllers (27 April 1992)
- Information Notice 1992-32, Problems Identified with Emergency Ventilation Systems for Near-Site (Within 10 Miles) Emergency Operations Facilities and Technical Support Centers (29 April 1992)
- Information Notice 1992-32, Problems Identified with Emergency Ventilation Systems for Near-Site (within 10 Miles) Emergency Operations Facilities and Technical Support Centers (29 April 1992)
- Information Notice 1992-33, Increased Instrument Response Time When Pressure Dampening Devices Are Installed (30 April 1992)
- Information Notice 1992-33, Increased Instrument Response Time When Pressure Dampening Devices are Installed (30 April 1992)
- Information Notice 1992-34, New Exposure Limits for Airborne Uranium and Thorium (6 May 1992)
- Information Notice 1992-35, Higher than Predicted Erosion/Corrosion in Unisolable Reactor Coolant Pressure Boundary Piping Inside Containment at a Boiling Water Reactor (6 May 1992)
- Information Notice 1992-35, Higher than Predicted Erosion/Corrosion in Unisolable Reactor Coolant Pressure Boundary Piping inside Containment at a Boiling Water Reactor (6 May 1992)
- Information Notice 1992-36, Intersystem LOCA Outside Containment (7 May 1992)
- Information Notice 1992-37, Implementation of the Deliberate Misconduct Rule (8 May 1992)
- Information Notice 1992-38, Implementation Date for the Revision to the EPA Manual of Protective Action Guides and Protective Actions for Nuclear Incidents (26 May 1992, Topic: Brachytherapy)
- Information Notice 1992-39, Unplanned Return to Criticality During Reactor Shutdown (13 May 1992, Topic: Fuel cladding)
- Information Notice 1992-40, Inadequate Testing of Emergency Bus Undervoltage Logic Circuitry (27 May 1992)
- Information Notice 1992-41, Consideration of Stem Rejection Load In Calculation of Required Valve Thrust (29 May 1992, Topic: Anchor Darling)
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