Turbine Overspeed and Reactor Cooldown During Shutdown EvolutionML031060633 |
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: |
02/08/1994 |
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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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IN-94-011, NUDOCS 9402020376 |
Download: ML031060633 (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
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 February 8, 1994 NRC INFORMATION NOTICE 94-11: TURBINE OVERSPEED AND REACTOR COOLDOWN
DURING SHUTDOWN EVOLUTION
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
PurDose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to a recent event involving the spurious opening of
turbine governor and stop valves and resultant turbine overspeed and reactor
coolant system cooldown due to a malfunctioning control system during a
shutdown evoluation. 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 September 12, 1992, the Diablo Canyon Power Plant, Unit 1, was in Mode 2 at
0 percent power. The Pacific Gas and Electric Company (the licensee) was
shutting down the reactor for a refueling outage. The main turbine had been
manually tripped and removed from service. The unit was subcritical, with
bank OD" control rods fully inserted and bank KCT rods at approximately
50 steps. To prevent excessive reactor coolant system cooldown, an operator
was dispatched to re-latch the main turbine. This causes the stop valve trip
pilot valves to close which isolates a main steam leakage path to the
condenser. However with the re-latching of the main turbine, the turbine
speed rapidly increased from about 1100 rpm to 1870 rpm; reactor coolant
temperature decreased from 284C [5430F] to 2790C [535'F]; and the
intermediate range nuclear instrumentation indication increased from
1.9 x 10P amps to 2.2 x 10 amps. At the governor valve overspeed setpoint to
of 103 percent (1854 rpm), the governor valves began to close. In response
these indications, the operators again tripped the main turbine. The
operators observed that reactor coolant system temperature continued to
decrease and tripped the reactor to prevent an inadvertent return to
criticality from the cooldown.
9402020376 eDA R f PC
I" Li
,S
i~t;i . ,
7.l
- v\,A 94-11 February 8, 1994 Discussion
During reactor operations at Diablo Canyon, turbine speed is regulated by the
positions of four governor valves (see Attachment 1) which are controlled by
the P2000 computer. When the turbine is tripped, pressure switch PS-22B (Low
Auto Stop 01 Pressure) is designed to provide a contact closure signal to the
P2000 computer. This signal is used by the P2000 computer to reset the main
turbine speed reference signal to 0 rpm. To prevent excessive cooldown
following a plant shutdown, the licensee re-latches the main turbine while the
stop valve equalizing valves are closed. Re-latching the turbine in this
manner closes the stop valve trip pilot valves, which isolates a steam leakage
path to the condenser.
During this event, PS-22B failed to close due to corrosion of internal switch
components. The failure of PS-22B allowed the P2000 main turbine speed
reference signal to remain at 1800 rpm. As the main turbine deviated from
1800 rpm during coastdown, the P2000 speed controller integrated the deviation
which resulted in a maximum speed-increase demand signal. Upon re-latching
the main turbine, governor valve FCV-141 responded to the P2000 demand signal
and opened in an attempt to return main turbine speed to 1800 rpm. The main
turbine accelerated rapidly to 103 percent (1854 rpm), at which point the
governor valve overspeed system closed the governor valves. At approximately
the same time that the governor valves began to close, the licensee tripped
the turbine. The maximum speed attained of 1870 rpm was below the main
turbine overspeed trip setpoint of 1980 rpm. The turbine trip system remained
operable throughout the event.
The mechanical components of PS-22B include a plunger rod, a bushing, and a
case. The plunger rod was fabricated of austenitic stainless steel, and the
bushing and case were fabricated of aluminum. These two materials are far
apart on the galvanic series. The resulting potential difference could result
in the formation of a galvanic cell, creating aluminum oxide buildup between
the plunger and the bushing. Corrosion product buildup, combined with a
static pressure system, is believed to have caused PS-22B to stick.
A similar event occurred at the James A. Fitzpatrick Nuclear Power Plant. On
December 28, 1992, during a refueling outage, the main turbine stop valves
spuriously opened when the main turbine trip system was reset. Testing of the
turbine electro-hydraulic control system revealed a failed Agastat time delay
relay in the primary trip/reset logic circuitry. The time delay relay allows
the turbine to be reset without opening the main turbine stop valves. This
failure of the relay allowed the electro-hydraulic control system speed
circuit to change from 0 rpm to 1800 rpm spontaneously, creating a demand
signal to open the main turbine stop valves. In this event, the main steam
isolation valves closed, which prevented an actual turbine overspeed.
I .
bA 94-11 Yebruary 8, 1994 The events discussed above are examples of how turbine control system failures
can result inunanticipated challenges to turbine overspeed protection systems
during all modes of operation.
This information notice requires no specific action or written response. If
you have any questions about the information inthis 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 contact: Eric J. Benner, NRR
(301) 504-1171 Attachments:
1. Main Steam Stop and Governor Valves
2. List of Recently Issued NRC Information Notices
FROM MAIN STEAM
FCV-1 45 FCV-146 FCV-1 41 142
...... ..................................... ..................
................................................................ ..
FCV-1 139 FCV-1 39, -140, -141, AND (
-142 ARE CONTROL VALVES
FCV-143, -144, -145, AND
-146 ARE STOP VALVES o
FCV-1 43 FROM MAIN STEAM
Attacdment 2 IN 94-11 February 8, 1994 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information Date of
Notice No. Subject Issuance Issued to
94-10 Failure of Motor-Operated 02/04/94 All holders of OLs or CPs
Valve Electric Power for nuclear power reactors.
Train due to Sheared or
Dislodged Motor Pinion
Gear Key
94-09 Release of Patients with 02/03/94 All U.S. Nuclear Regulatory
Residual Radioactivity Commission medical
from Medical Treatment and licensees.
Control of Areas due to
Presence of Patients Con- taining Radioactivity
Following Implementation
of Revised 10 CFR Part 20
94-08 Potential for Surveil- 01/01/94 All holders of OLs or CPs
lance Testing to Fail for nuclear power reactors.
to Detect an Inoperable
Main Steam Isolation Valve
93-26, Grease Solidification 01/31/94 All holders of OLs or CPs
Supp. 1 Causes Molded-Case for nuclear power reactors.
Circuit Breaker Failure
to Close
94-07 Solubility Criteria for 01/28/94 All byproduct material and
Liquid Effluent Releases fuel cycle licensees with
to Sanitary Sewerage Under the exception of licensees
the Revised 10 CFR Part 20 authorized solely for
sealed sources.
94-06 Potential Failure of 01/28/94 All holders of OLs or CPs
Long-Term Emergency for boiling water reactors.
Nitrogen Supply for the
Automatic Depressurization
System Valves
93-85, Problems with X-Relays 01/20/94 All holders of OLs or CPs
Rev. 1 in DB- and DHP-Type for nuclear power reactors.
Circuit Breakers Manu- factured by Westinghouse
OL = Operating License
CP = Construction Permit
IN 94-11 February 8, 1994 The events discussed above are examples of how turbine control system failures
can result in unanticipated challenges to turbine overspeed protection systems
during all modes of operation.
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.
Oginal sined by
Brian K. Grimes
Brian K. Grimes, Director
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contact: Eric J. Benner, NRR
(301) 504-1171 Attachments:
1. Main Steam Stop and Governor Valves
2. List of Recently Issued NRC Information Notices
- See previous concurrences
OFC OEAB:DORS SC/OEAB:DORS PUB:ADM C/OEAB:DORS
NAME EBenner* EGoodwin* Tech Ed* AChaffee*
DATE 03/01/93 [03/05/93 I03/02/93 J 03/31/931j
OFC OGCB:DORS C/OGCB:DORS 1 I
NAME DKirkpatrick* GMarcus*
l DATE 04/08/93 04/09/93 102/17 /94
[OFFICIAL RECORD COPY]
DOCUMENT NAME: 94-11.IN
IN 94-XX
February xx, 1994 The events discussed above are examples of how turbine control system failures
can result in unanticipated challenges to turbine overspeed protection systems
during all modes of operation. 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 contact: Eric J. Benner, NRR
(301) 504-1171 Attachments:
1. Main Steam Stop and Governor Valves
2. List of Recently Issued NRC Information Notices
- See previous concurrences
OFC OEAB:DORS SC/OEAB:DORS PUB:ADM C/OEAB:DORS
NAME EBenner* EGoodwin* Tech Ed* AChaffee*
DATE 03/01/93 03/05/93 [03/02/93 03/31/93 OFC OGCB:DORS C/OGCB:DORS D/DORS
NAME DKirkpatrick* GMarcus* BGrimes
DATE 04/08/93 04/09/93 [ / /94 j.
AAAW
[OFFICIAL RECORD COPY]
DOCUMENT NAME: S:\DORSSEC\DCTURBIN.IN
IN 93-XX
April xx, 1993 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 Contact:
Eric J. Benner, NRR
(301) 504-1171 Attachments:
1. Main Steam Stop and Governor Valves
2. List of Recently Issued NRC Information Notices
- See previous concurrences
OFC OEAB:DORS SC/OEAB:DORS PUB:ADM C/OEAB:DORS
NAME EBenner* EGoodwin* Tech Ed* AChaffee*
DATE 03/01/93 103/05/93 03/02/93 103/31/93 OFC C/OGCB:DORS D/DORS
NAME GMarcusjtf BGrimes
DATE q /'T /93 / /93 I /93 DATE 'dI¶193 Q4b id4 f 9f3
[OFFICIAL RECORD COPY]
DOCUMENT NAME: S:\DORS SEC\DCTURBIN.IN
IN 93-XX
April XX, 1993 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 Contact:
Eric J. Benner, NRR
(301) 504-1171 Attachments:
1. Main Steam Stop and Governor Valves
2. List of Recently Issued NRC Information Notices
OEAB:DORS* SC/OEAVDORS PUB:ADM* C/OEAB:DORS C/OGCB:DORS
EBenner EGoodwin Tech Ed AChaffee GMarcus
3/1/93 3/X¢/93 3/2/93 3/31/93 / /93 D/DORS
BGrimes
/ /93
Document Name: G:\EJB1\DCTURBIN.IN
OEAB:DORS SC/OEAB:DORS PUB:ADM C/OEAB:DORS C/OGCB:DORS
EBenner £60 EGoodwin Tech Ed 3ManihAChaffee GMarcus
3 / I /93e / /93 1 A
3 /12/9 / /93 / /93 D/DORS
BGrimes
/ /93 Document Name: G:\EJB1\DCTURBIN.IN
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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)
- 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)
- 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)
- 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)
- 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)
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