Problem with Henry Pratt Motor-Operated Butterfly Valves ML031060541 Person / Time 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 , 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 , Crane Issue date:
09/26/1994 From:
Grimes B Office of Nuclear Reactor Regulation To:
References IN-94-067 , NUDOCS 9409200069Download: ML031060541 (8)
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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 ,
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 ,
Crane Category:NRC Information Notice
[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 [[: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]] OR [[:Crane]] </code>.
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Contents
1 UNITED STATES
2 OFFICE OF NUCLEAR REACTOR REGULATION
3 September 26, 1994
4 BUTTERFLY VALVES
5 Addressees
6 Purpose
7 Description of Circumstances
7.1 The licensee found that the pump suction valve was
7.2 The adapter plates
7.3 Related Generic Communications
7.4 Division of Operating Reactor Support
7.5 Thomas G. Scarbrough, NRR
7.6 V Attachnent 1
7.7 September 26, 1994
7.8 Attachment 2
7.9 September 26, 1994
7.10 NRC INFORMATION NOTICES
7.11 Driven Pumps Caused by
7.12 Potential Errors in
7.13 Dose Calculations
7.14 Computerized Treatment
7.15 Reactivity Insertion
7.16 Limits for High Burnup
7.17 Boric Acid Corrosion of
7.18 Caused by Cladding Cracks
7.19 Leaks and Tube Ruptures
7.20 Powell Gate Valve Disc
7.21 Leaking Shutdown Cooling
7.22 Cooper Nuclear Station
7.23 All holders of OLs or CPs
7.24 Al U.S. Nuclear Regulatory
7.25 All holders of OLs or CPs
7.26 All holders of OLs or CPs
7.27 All holders of OLs or CPs
7.28 All holders of OLs or CPs
7.29 All holders of OLs or CPs
7.30 All holders of OLs or CPs
7.31 All holders of OLs or CPs
7.32 Brian K. Grimes, Director
7.33 Office of Nuclear Reactor Regulation
7.34 Scot A. Greenlee, Region I
7.35 Thomas G. Scarbrough, NRR
7.36 Brian K. Grimes, Director
7.37 Office of Nuclear Reactor Regulation
7.38 Scot A. Greenlee, Region I
7.39 Thomas G. Scarbrough, NRR
7.40 Scot A. Greenlee, Region I
7.41 Thomas G. Scarbrough, NRR
7.42 Related Generic Communications
7.43 Division of Operating Reactor Support
7.44 Scot A. Greenlee, RI
7.45 Thomas G. Scarbrough, NRR
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON , D.C.
20555
September 26, 1994
NRC INFORMATION NOTICE 94-67:
PROBLEM WITH HENRY PRATT MOTOR-OPERATED
BUTTERFLY VALVES
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 a problem with Henry Pratt motor-operated
butterfly valves that can lead to the decoupling of the valve operator from
the valve stem.
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 October 17, 1993, the Duquesne Light Company conducted a full flow
surveillance test on a recirculation spray pump at Beaver Valley Power
Station, Unit 2. The pump did not establish adequate flow or discharge
pressure during the test.
The licensee found that the pump suction valve was
shut, though the annunciator in the control room indicated it fully open. As
the result of the investigation, the licensee found that the valve operator
had decoupled from the valve stem, allowing the operator to move independently
of the valve. Two of the three other recirculation pump suction valves were
starting to decouple because the valve spline adapters separated from the
operator drive sleeves .
On December 10, 1993, the licensee reported to NRC in accordance with the
requirements of 10 CFR Part 21, "Reporting of Defects and Noncompliance,",that
the recirculation pump suction valve disc could disengage from the motor- operator which could cause the recirculation spray system to operate in an
unacceptable manner.
Discussion
The recirculation spray pump suction valves at Beaver Valley Unit 2 are
12 inch nominal size Henry Pratt 1400 series butterfly valves with Limitorque
HBC-1 operators. The drive sleeve on a Limitorque HBC valve operator rotates
a spline adapter.
The spline adapter is keyed to the valve stem, but the key
does not prevent the adapter from moving down the valve stem toward the valve.
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IN 94-67
j _>September 26, 1994 If the spline adapter slips down the valve stem, it will disconnect from the
drive sleeve . On a Henry Pratt valve, the spline adapter is held in position
by an adapter plate, which is designed to permit passage of the valve stem, but not the spline adapter. Additionally, the valve bonnet plate, which is
located below the adapter plate, isT designed the same way.
The adapter plates
and bonnet plates were designed and manufactured by Henry Pratt.
Duquesne Light Company found that the center holes in the valve bonnet plates
and adapter plates were about 1.3 cm (0.5 inches] larger (in diameter) than
the corresponding design dimensions. This was sufficient to allow the spline
adapters to slip down the valve stem during operation of the valve.
This is
shown in Figure 1.
The licensee checked all 54 Henry Pratt butterfly valves at the Beaver Valley
Nuclear Power Station for proper adapter plate and bonnet plate dimensions.
No problems were noted beyond the recirculation pump suction valves.
The
licensee placed temporary spline adapter retaining clamps on the recirculation
spray pump suction valves pending permanent modification.
Related Generic Communications
The NRC discussed a separate root cause of decoupling of a valve from its
motor-operator in NRC Office of Inspection and Enforcement (I&E) Circular
80-12, "Valve-Shaft-to-Actuator Key May Fall Out of Place When Mounted Below
Horizontal Axis," dated May 14, 1980, and I&E Information Notice 85-67 ,
"Valve-Shaft-to-Actuator Key may fall out of Place When Mounted Below
Horizontal Axis," dated August 8, 1985.
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
orig /s/'d by
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts: Scot A. Greenlee, RI
Thomas G. Scarbrough, NRR
(412) 643-2000
(301) 504-2794 CIGrimes/for
Attachments:
1. Figure 1 - Henry Pratt Butterfly Valves With Limitorque Motor Operator
2. List of Recently Issued NRC Information Notices
see WDLanning memo to AJKugler date May 26, 1994 AcA(PI
and Drevious concurrence sheets
DOCUMENT NAME:
94-67.IN M'iLtR )ir.W-rs
r7uKUT
.,
OFFICE
NAME
SAGreenlee
I JCLinville
WDLanning
RJKiessel
DATE
7/13/94
[ 5/25/94
5/25/94 J 7/11/94 OFFICE
l *D:DE/NRR
NAME
l JMain
TGScarbrough
RHWessman
BWSheron
DATE [
7/12/94 l 7/31/94 J 8/ 2/94 l 8/ 9/94 OFFICE
jD:DORS/NRR
NAME
LJNorrholm
CERossi
J
ELDoolittle
BKGrimes il
DATE
8/ 8/94
18/
9/94
1 8/20/94
1 09/7P/94 V
V Attachnent 1
IN 94-67
September 26, 1994
Figure 1 Henry Pratt Butterfly Valve
with Limitorque Motor Operator
Attachment 2
IN 94-67
September 26, 1994
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
94-66
94-65
94-64
94-63
94-62 Overspeed of Turbine-
Driven Pumps Caused by
Governor Valve Stem
Binding
Potential Errors in
Manual Brachytherapy
Dose Calculations
Generated Using a
Computerized Treatment
Planning System
Reactivity Insertion
Transient and Accident
Limits for High Burnup
Fuel
Boric Acid Corrosion of
Charging Pump Casing
Caused by Cladding Cracks
Operational Experience
on Steam Generator Tube
Leaks and Tube Ruptures
Corrosion of William
Powell Gate Valve Disc
Holders
Potential Overpressuriza- tion of Main Steam System
Leaking Shutdown Cooling
Isolation Valves at
Cooper Nuclear Station
Accelerated Dealloying of
Cast Aluminum-Bronze
Valves Caused by Micro- biologically Induced
Corrosion
09/19/94
09/12/94
08/31/94
08/30/94
08/30/94
08/25/94
08/22/94
08/19/94
08/17/94
All holders of OLs or CPs
for nuclear power reactors.
Al U.S. Nuclear Regulatory
Commission medical
licensees.
All holders of OLs or CPs
for nuclear power reactors
and all fuel fabrication
licensees.
All holders of OLs or CPs
for pressurized water
reactors.
All holders of OLs or CPs
for pressurized water
reactors.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for pressurized-water
reactors.
All holders of OLs or CPs
for nuclear power reactors.
All holders of OLs or CPs
for nuclear power reactors.
94-61
94-60
94-30,
Supp. 1
94-59 OL = Operating License
CP = Construction Permit
IN 94-XX
July 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:
Scot A. Greenlee, Region I
(412) 643-2000
Thomas G. Scarbrough, NRR
(301) 504-2794 Attachments:
1. Figure 1 - Henry Pratt Butterfly Valves With Limitorque Motor Operator
2. List of Recently Issued NRC Information Notices
see WDLanning memo to AJKugler date May 26, 1994 and previous concurrence sheets
OFFICE
NAME
SAGreenlee
JCLinville
WDLanning
RJKiessel
DATE
7/13/94
5/25/94
5/25/94
7/11/94 OFFICE
NAME
JMain
TGScarbrough
RHWessman
BWSheron
DATE
7/12/94
7/31/94
8/ 2/94
8/ 9/94 OFFICE_ *C:RVIB/NRR
C
B/NRRD:DORS/NRR
NAME
LJNorrholm
RLSpessard
i ttle
BKGrimes
DATE
8/ 8/94
8/ 9/94
8 / /94
8/ /94 Document Name:
G:\\RJK\\NRCINS\\NRCIN.461
IN 94-XX
July 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:
Scot A. Greenlee, Region I
(412) 643-2000
Thomas G. Scarbrough, NRR
(301) 504-2794 Attachments:
1. Figure 1 - Henry Pratt Butterfly Valves With Limitorque Motor Operator
2. List of Recently Issued NRC Information Notices
see WDLanning memo to AJKugler date May 26, 1994 and previous concurrence sheets
OFFICE J
NAME
SAGreenlee
JCLinville
WDLanning
RJKiessel
DATE
7/13/94
5/25/94
5/25/94
7/11/94 OFFICE
EMEQ0_
C:E
/K
-RR
l
NAME
JMain
TGSc
arough
RHWAlSan
j
l
DATE
7/12/94
7/51/94
1p-9 /94
/g/94 OFFICE
C:q I I/NRR
D:DRIL/NRR
C:OGCB/NRR
D:DORS/NRR
NAME
olin
ELDoolittle
BKGrimes
DATE
Y/7
94
/
94
7/ /94
7/ /94 Document Name:
G:\\RJK\\NRCINS\\NRCI .461 Wf C-
.1 - t
94-P
Technical contact(s):
Scot A. Greenlee, Region I
(412) 643-2000
Thomas G. Scarbrough, NRR
(301) 504-2794 Attachments:
1. Figure 1 - Henry Pratt Butterfly Valves With Limitorque Motor Operator
2. List of Recently Issued NRC Information Notices
see WDLanning memo to AJKugler date May 26, 1994 and previous concurrence sheets
OFFICE
Region I
Region I
Region I
OGCB/NRR_
NAME
SAGreenlee
JCLinville
WDLanning
RJKiess4 K
DATE
5/ /94
5/ /94
5/ /94
7/11/9 OFFICE
Tech. Ed.
EMEB/NRR
C:EMEB/NRR
D:DE/NRR
NAME
_____ _
9 TGScarbrough
RHWessman
BWSheron
DATE
7/12 /94
7/ /94
7/ /94
7/ /94 OFFICE
C:RVIB/NRR
D:DRIL/NRR
C:OGCB/NRR
D:DORS/NRR
NAME
LJNorrholm
CERossi
ELDoolittle
BKGrimes
DATE
7/ /94
7/ /94
7/ /94
7/ /94 Document Name:
G:\\RJK\\NRCINS\\NRCIN.461
IN 94-67 September 26,
1994 If the spline adapter slips down the valve stem, it will disconnect from the
drive sleeve . On a Henry Pratt valve, the spline adapter is held in position
by an adapter plate, which is designed to permit passage of the valve sLem, but not the spline adapter. Additionally, the valve bonnet plate, which is
located below the adapter plate, is designed the same way. The adapter plates
and bonnet plates were designed and manufactured by Henry Pratt.
Duquesne Light Company found that the center holes in the valve bonnet plates
and adapter plates were about 1.3 cm [0.5 inches] larger (in diameter) than
the corresponding design dimensions. This was sufficient to allow the spline
adapters to slip down the valve stem during operation of the valve.
This is
shown in Figure 1.
The licensee checked all 54 Henry Pratt butterfly valves at the Beaver Valley
Nuclear Power Station for proper adapter plate and bonnet plate dimensions.
No problems were noted beyond the recirculation pump suction valves.
The
licensee placed temporary spline adapter retaining clamps on the recirculation
spray pump suction valves pending permanent modification.
Related Generic Communications
The NRC discussed a separate root cause of decoupling of a valve from its
motor-operator in NRC Office of Inspection and Enforcement (I&E) Circular
80-12, "Valve-Shaft-to-Actuator Key May Fall Out of Place When Mounted Below
Horizontal Axis," dated May 14, 1980, and I&E Information Notice 85-67 ,
"Valve-Shaft-to-Actuator Key may fall out of Place When Mounted Below
Horizontal Axis," dated August 8, 1985.
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, DirectoX"
Division of Operating Reactor Support
Office of Nuclear Reactor Regulation
Technical contacts-
Scot A. Greenlee, RI
(412) 643-2000
Thomas G. Scarbrough, NRR
(301) 504-2794 Attachments:
1. Figure 1 - Henry Pratt Butterfly Valves With Limitorque Motor Operator
2. List of Recently Issued NRC Information Notices
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 , Topic : Overspeed trip , Overspeed )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 : Loss of Offsite Power , Overspeed )Information Notice 1994-13, Unanticipated and Unintended Movement of Fuel Assemblies and Other Components Due to Improper Operation of Refueling Equipment (28 June 1994 , Topic : Spent fuel rack )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 , Topic : Overspeed )Information Notice 1994-15, Radiation Exposures During an Event Involving a Fixed Nuclear Gauge (2 March 1994 , Topic : Overspeed )Information Notice 1994-16, Recent Incidents Resulting in Offsite Contamination (3 March 1994 , Topic : Overspeed )Information Notice 1994-17, Strontium-90 Eye Applicators: Submission of Quality Management Plan (QMP), Calibration, and Use (11 March 1994 , Topic : Brachytherapy , Overspeed )Information Notice 1994-17, Strontium-90 Eye Applicators: Submission of Quality Management Plan (Qmp), Calibration, and Use (11 March 1994 , Topic : Brachytherapy , Overspeed )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 , Topic : Inactive license )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 )Information Notice 1994-24, Inadequate Maintenance of Uninterruptible Power Supplies & Inverters (24 March 1994 , Topic : Safe Shutdown )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 : Water hammer )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 )Information Notice 1994-27, Facility Operating Concerns Resulting from Local Area Flooding (31 March 1994 )Information Notice 1994-28, Potential Problems with Fire-Barrier Penetration Seals (5 April 1994 , Topic : Fire Barrier , Operability Determination )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 , Local Leak Rate Testing )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 : Stress corrosion cracking , 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 , Stress corrosion cracking )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 , Topic : Stress corrosion cracking )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 , Gas accumulation )Information Notice 1994-37, Misadministration Caused by a Bent Interstitial Needle During Brachytherapy Procedure (27 May 1994 , Topic : Stress corrosion cracking , 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 1994-42, Cracking in the Lower Region of the Core Shroud in Boiling-Water Reactors (7 June 1994 , Topic : Stress corrosion cracking )Information Notice 1994-43, Determination of Primary-to-Secondary Steam Generator Leak Rate (10 June 1994 , Topic : Grab sample , Main Steam Line Radiation Monitor )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 , Topic : Unidentified leakage )Information Notice 1994-47, Accuracy of Information Provided to NRC During the Licensing Process (21 June 1994 )... further results