Snubber Lubricant Degradation in High-Temperature EnvironmentsML031060631 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:
06/30/1994 From:
Grimes B Office of Nuclear Reactor Regulation To:
References IN-94-048 , NUDOCS 9406240045Download: ML031060631 (20)
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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 ,
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Limerick ,
North Anna ,
Turkey Point ,
River Bend ,
Vermont Yankee ,
Crystal River ,
Haddam Neck ,
Ginna ,
Diablo Canyon ,
Callaway ,
Vogtle ,
Waterford ,
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Farley ,
Robinson ,
Clinton ,
South Texas ,
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Cook ,
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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>.
Contents
1 NUCLEAR REGULATORY COMMISSION 2 June 30, 1994 3 SNUBBER LUBRICANT DEGRADATION 4 Addressees 5 Purpose
5.1 DescriDtion of Circumstances 5.2 The licensee determined that the 5.3 Elevated temperatures caused the 5.4 PSA mechanical snubbers 5.5 The physical conditions of 5.6 Past industry 5.7 For example, of all the functionally 5.8 In the case of Farley Unit 2, none of the 5.9 In December of 1993, PSA sent letters to all 5.10 PSA and the SNUG 5.11 SNUG also requested utilities 5.12 Division of Operating Reactor Support 5.13 Floyd S. Cantrell, RII 5.14 Arnold J. H. Lee, NRR 5.15 List of Recently Issued NRC Information Notices 5.16 June 30, 1994 LIST OF RECENTLY ISSUED 5.17 Assemblies and other 5.18 Operation of Refueling 5.19 Accuracy of Information 5.20 NonConservative Reactor 5.21 Failure Mechanism for 5.22 Main Steam Isolation 5.23 Inadequate Maintenance 5.24 Generator Leak Rate 5.25 Region of the Core 5.26 Problems with General 5.27 Overload Relay Ambient 5.28 All holders of OLs or CPs 5.29 All U.S. Nuclear Regulatory 5.30 All holders of OLs or CPs 5.31 All holders of OLs or CPs 5.32 All holders of OLs or CPs 5.33 All holders of OLs or CPs 5.34 All holders of OLs or CPs 5.35 All holders of OLs or CPs 5.36 Brian K. Grimes, Director 5.37 Office of Nuclear Reactor Regulation 5.38 Floyd S. Cantrell, RII 5.39 Arnold J. H. Lee, NRR 5.40 List of Recently Issued NRC Information Notices 5.41 Brian K. Grimes, Director 5.42 Office of Nuclear Reactor Regulation 5.43 Floyd S. Cantrell, Region II 5.44 Arnold J. H. Lee, NRR 5.45 List of Recently Issued NRC Information Notices 5.46 Brian K. Grimes, Director 5.47 Office of Nuclear Reactor Regulation 5.48 Floyd S. Cantrell, Region II 5.49 Arnold J. H. Lee, NRR 5.50 List of Recently Issued NRC Information Notices
NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON , D.C.
20555
June 30, 1994 NRC INFORMATION NOTICE 94-48:
SNUBBER LUBRICANT DEGRADATION IN HIGH-TEMPERATURE ENVIRONMENTS
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 the possible degradation of the lubricant used
in mechanical snubbers manufactured by Pacific Scientific (PSA ) when the
snubber is used in a high-temperature environment. 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.
DescriDtion of Circumstances During the ninth refueling outage at the Joseph M. Farley Nuclear Plant, Unit 2 at the end of 1993, the Southern Nuclear Operating Company (the
licensee) functionally tested a number of safety-related snubbers as
prescribed by its technical specification surveillance requirements.
From an
original test sample of 88 mechanical snubbers , the licensee identified
8 failures. Two of these failures, a PSA-1/4 on a steam generator blowdown
line and a PSA-10 on a pressurizer safety valve, led to the discovery of four
additional snubbers that failed their functional tests for common causes
(three more PSA-1/4s on steam generator blowdown lines and another PSA-10 on
the pressurizer).
The licensee concluded that high environmental temperatures (ranging from 38 to 93 *C [100 to 220 'F]) for extended periods had degraded the internal
lubricants used in these PSA snubbers .
The licensee determined that the failure mechanism of the PSA-1/4s was a loss of lubricant, and for the PSA-10s
it was a breakdown of lubricant viscosity.
Elevated temperatures caused the PSA-1/4 snubber grease to bake and dry up, resulting in complete lockup when
these snubbers were tested.
For the PSA-10 snubbers , the high temperatures
caused the grease to lose almost all viscosity,iresulting in insufficient drag
resistance during testing.
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IN 94-48 June 30, 1994 The licensee subsequently replaced all failed snubbers , and conducted physical
inspections and engineering evaluations to ascertain if any structural damage
had occurred. No support damage or system operability concerns were
identified by the licensee.
Discussion
The licensee does not have the capability to overhaul mechanical snubbers .
Consequently, unlike their hydraulic counterparts, mechanical snubbers are not
part of any routine preventive maintenance program.
are purchased and installed with the expectation that they are maintenance
free for the duration of their life in the plant.
The physical conditions of all snubbers are examined by visual inspections which, depending on the number
of unacceptable snubbers identified in the previous inspection interval, could
be performed once in every 36 months. Although the operability of some
snubbers is verified by functional testing each refueling outage, only a small
sample of the snubber population is exercised and tested.
Past industry experience with snubber failures has demonstrated that the failure modes of
mechanical snubbers are not readily discernible by visual inspection or even
physical str.'ing. Only functional testing under actual load conditions
appears to confirm their operability.
For example, of all the functionally tested mechanical PSA snubber failures identified by the licensee for both
units since commercial operation, only one was discovered by visual
inspection.
Depending on the size and distribution of the snubber population, sample
selection techniques and failure rates, it may take decades before all plant
snubbers are actually tested.
In the case of Farley Unit 2, none of the failed PSA snubbers had been tested since the unit began commercial operation
in 1981.
The subject PSA-1/4 and PSA-10 snubbers were installed during
original construction and were about 15 years old.
The licensee concluded that the failure of PSA snubbers as the result of
lubricant degradation after extended exposure to high temperatures is a new
issue.
The Snubber Utility Group (SNUG), of which the licensee is a member, and PSA are aware of the issue.
In December of 1993, PSA sent letters to all users of its snubbers , including Farley Unit 2, informing them of these
grease-related problems. Although PSA snubbers are lubricated with a
radiation-resistant grease (i.e., NRRG-159), recent test results from PSA and
the industry also indicate there could be an adverse impact on the service
life of snubbers in environments with elevated temperatures.
PSA and the SNUG Lubrication Working Group have requested users to inspect and evaluate all PSA
snubbers removed from service because of preventive maintenance or functional
failure for possible lubrication degradation.
SNUG also requested utilities to forward any relevant information using a standard data sheet.
~-
IN
94-48 June 30, 1994 PSA and SNUG are establishing a database to analyze and develop criteria based
on time and temperature for a service life program to be used by all
utilities.
The NRC staff is following the above industry activities and will
evaluate whether additional NRC actions are necessary.
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.
nanK. Grimes,
Division of Operating Reactor Support Office of Nuclear Reactor Regulation
Technical contacts:
Floyd S. Cantrell, RII (404) 331-5534
Arnold J. H. Lee, NRR (301) 504-2758 Attachment:
List of Recently Issued NRC Information Notices Attaachment
IN 94-48
June 30, 1994 LIST OF RECENTLY ISSUED NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
94-13, Supp.
1
94-47
94-46
94-45
94-44
94-43
94-42
94-41 Unanticipated and Unin- tended Movement of Fuel
Assemblies and other Components due to Improper
Operation of Refueling Equipment
Accuracy of Information Provided to NRC during
the Licensing Process
NonConservative Reactor Coolant System Leakage
Calculation
Potential Common-Mode
Failure Mechanism for Large Vertical Pumps
Main Steam Isolation Valve Failure to Close
on Demand because of
Inadequate Maintenance and Testing
Determination of Primary- to-Secondary Steam
Generator Leak Rate Cracking in the Lower
Region of the Core Shroud in Boiling-Water
Reactors
Problems with General Electric Type CR124
Overload Relay Ambient Compensation
06/28/94
06/21/94
06/20/94
06/17/94
06/16/94
06/10/94
06/07/94
06/07/94
All holders of OLs or CPs for nuclear power reactors.
All U.S. Nuclear Regulatory Commission Material
Licensees.
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 pressurized water
reactors.
All holders of OLs or CPs for boiling-water reactors
(BWRs ).
All holders of OLs or CPs for nuclear power reactors.
OL = Operating License
CP = Construction Permit
IN 94-48 June 30, 1994 PSA and SNUG are establishing a database to analyze and develop criteria based
on time and temperature for a service life program to be used by all
utilities.
The NRC staff is following the above industry activities and will
evaluate whether additional NRC actions are necessary.
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.
riginal gned by
8rian K. Grimes
Brian K. Grimes, Director Division of Operating Reactor Support
Office of Nuclear Reactor Regulation Technical contacts:
Floyd S. Cantrell, RII (404) 331-5534
Arnold J. H. Lee, NRR (301) 504-2758 Attachment:
List of Recently Issued NRC Information Notices forwarded by JRJohnson memorandum to BKGrimes dated 3/8/94 see previous concurrence OFFICE
NAME
FSCantrell
DMVerrelli
JRJohnson
RJKiessel
[
DATE
3/ 8/94
3/ 8/94
3/ 8/94
4/19/94 OFFICE
NAME
MFMejac
AJHLee
JANorberg
BWSheron
DATE
4/19/94
4/21/94,
4/22/94
5/17/94 OFFICE
OGCB/NRR
=
NAME
AJKugler*
i
s
I
DATE
5/25/94
06/Zf(/94 Document Name:
94-48.IN
IN 94-xx
May xx, 1994 PSA and SNUG are establishing a database to analyze and develop criteria based
on time and temperature for a service life program to be used by all
utilities.
Both of these organizations recognize that high temperatures seem
to be the leading cause of lubrication breakdown in snubbers . The NRC staff
is following the above industry activities closely and will take appropriate
regulatory actions deemed necessary.
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:
Floyd S. Cantrell, Region II (404) 331-5534
Arnold J. H. Lee, NRR (301) 504-2758 Attachment:
List of Recently Issued NRC Information Notices forwarded by JRJohnson memorandum to BKGrimes dated 3/8/94 see previous concurrence OFFICE
NAME
FSCantrell
DMVerrelli
JRJohnson
RJKiessel
DATE
3/ 8/94
3/ 8/94
3/ 8/94
4/19/94 OFFICE
NAME
MFMejac
AJHLee
JANorberg
BWSheron
DATE
4/19/94
4/21/94
4/22/94
5/17/94 OFFICE
OGCB/NRR
DORS/NRR
l
l
NAME
AJKugler
BKGrimes
DATE
5/2 794
5/
/94
_
Document name:
b:\\KJK\\NKLNb\\NKL1N.441
IN 94-xx
April xx, 1994 utilities.
Both of these organizations recognize that high temperatures seem
to be the leading cause of lubrication breakdown in snubbers .
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:
Floyd S. Cantrell, Region II (404) 331-5534
Arnold J. H. Lee, NRR (301) 504-2758 Attachment:
List of Recently Issued NRC Information Notices forwarded by JRJohnson memorandum to BKGrimes dated 3/8/94 see previous concurrence OFFICE l *Region II
l *Region II
l *Region II
l *OGCB/NRR
NAME
FSCantrell
DMVerrelli
JRJohnson
RJKiessel
DATE
3/ 8/94
3/ 8/94
3/ 8/94
4/19/94 OFFICE
EMEERRR
k AE/
N
NAME
MFMejac
A
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r erg
BWShero
DATE
4/19/94
4N-
/94
4
4/t-94
4/ %94\\
OFFICE
OGCB/NRR
DORS/NRR
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NAME
AJKugler
BKGrimes
DATE
4/ /94
4/ /94 VIU
Document Name:
b:\\KJK\\NKL1Nb\\NKL1N.441
forwarded by JRJohnson memorandum to BKGrimes dated 3/8/94 see previous concurrence OFFICE
OGCB/NRR A AA
NAME
FSCantrell
DMVerrelli
JRJohnson
RJKiessel
DATE
3/ 8/94
3/ 8/94
3/ 8/94
4//M/94 OFFICE
Tech Editor
EMEB/NRR
[ EMEB/NRR
l DE/NRR
NAME
A
d
Jo +
JHL &
JANorberg
BWSheron
DATE
4/k?/94
4/'1/94
4/ /94
4/ /94 OFFICE
OGCB/NRR
DORS/NRR
_
NAME
AJKugler
BKGrimes
DATE
4/ /94
4/ /94 Document Name:
G:\\RJK\\NRCINS\\NRCIN.441
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
