Information Notice 1993-26, Grease Soldification Causes Molded-Case Circuit Breaker Failure to Close: Difference between revisions
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| issue date = 01/31/1994 | | issue date = 01/31/1994 | ||
| title = Grease Soldification Causes Molded-Case Circuit Breaker Failure to Close | | title = Grease Soldification Causes Molded-Case Circuit Breaker Failure to Close | ||
| author name = Grimes B | | author name = Grimes B | ||
| author affiliation = NRC/NRR | | author affiliation = NRC/NRR | ||
| addressee name = | | addressee name = | ||
Revision as of 05:24, 14 July 2019
UNITED STATES NUCLEAR REGULATORY
COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 January 31, 1994 NR2' INFORMATION
NOTICE 93-26, SUPPLEMENT
1: GREASE SOLIDIFICATION
CAUSES MOLDED-CASE
CIRCUIT BREAKER FAILURE TO CLOSE
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 supplement
information
regarding
a problem with a 400-amp frame, 600-V ac molded-case
circuit breaker manufactured
by General Electric Corporation (GE) (Part No. TJK436Y400)
which failed to close when required due to grease solidification.
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 March 26, 1992, an engineered
safety feature (ESF) actuated at the Nine Mile Point Nuclear Station Unit 2 (NMP2) because of the loss of output power from an uninterruptible
power supply (UPS) while the loads were being transferred
from UPS power to the maintenance
supply power. During the transfer, the maintenance
supply output circuit breaker (CB-4) failed to close, causing a loss of power to the standby gas treatment
system radiation monitoring
cabinet, a false-high
radiation
signal, a group 9 (primary containment
purge system) primary containment
isolation, the loss of a control room fire panel annunciator, and a loss of communication
between the radiation monitoring
system computer and non-Class
IE radiation
monitors.
The operator immediately
took corrective
action to close circuit breaker CB-4 manually to restore the UPS loads. The UPS loads lost power for approximately
12 minutes during the event.After Information
Notice (IN) 93-26 was issued on April 7, 1993, additional
information
was obtained from GE and NMP2. The additional
information
in this supplement
is intended to assist recipients
in determining
the significance
of this potential
failure mode at their facilities.
-s 0900&S 9401250302
- i4 i_ (O3i 03017?1. RETURN TO REGULATGRY
CENTRAL FILES ROO&U
KI < 93-26, Supp. I January 31, 1994 Discussion
Niagara Mohawk Power Corporation, the licensee for Nine Mile Point 2 (LER 92-007-00), and Wyle Laboratories (Report No. 42370-RCCB-I)
determined
that circuit breaker CB-4 had failed to close because the grease used at the pivot points inside the breaker had dried out and solidified.
When the grease dried out, the metal-to-metal
contact areas experienced
increased
friction and eventual gouging. The friction caused the breaker to become increasingly
more difficult
to close, until, finally, the breaker would not close at all. The licensee located all breakers of the same make, model, and year as the one that failed and scheduled
their replacement.
Certain observations
were made in the NMP2 analysis relative to these breakers: 1. The safety function of these breakers is both to open and close automatically.
Normally, the only electrical
safety function of a breaker is its ability to trip. None of the breakers of this type at Nine Mile Point 2 have failed to trip when required.2. Due to the nature of the application
of these molded-case
switches, they were cycled extensively (approximately
200-400 times). This is more than a normal molded-case
circuit breaker used in a distribution
panel.3. The breakers were in close proximity
to the UPS transformers
causing operation
above normal ambient conditions, which may or may not have contributed
to the solidification
of the grease.GE has stated that in early 1980 the soap-based
and clay-based
grease used in this style molded-case
circuit breakers was replaced with a synthetic lubricant
as a product enhancement.
However, older molded-case
circuit breakers using the clay-based
and soap-based
grease may still be in use at other plants, in similar applications.
-V zi 93-26, Supp. 1 January 31, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact the technical
contact listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.nan K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
contact: Mark D. Pratt, NRR (301) 504-2701 Attachment:
List of Recently Issued NRC Information
Notices
- ~'~IN 93-26, Supp. 1 January 31, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact the technical
contact listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.Odginal fgned by Brian K. Grimes Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
contact: Mark D. Pratt, NRR (301) 504-2701 Attachment:
List of Recently Issued NRC Information
Notices EELB Concurrence
obtained by M.D. Pratt*EELB:DE:NRR
MDPratt 12/22/93*D/DE WHodges 01/12/94 SC/EELB:DE:NRR
C/EELB:DE:NRR
- OGCB:DORS:NRR
EWWeiss* CHBerlinger*
/~NECampbell
12/17/93*C/OGCB:DORS:NRR
/D RR GHMarcus 12/22/93 "01k (/94*RPB:ADM Tech Ed 12/22/93 DOCUMENT NAME: 93-26SP1.IN
r- IN 93-26, Supp. 1 January xx, 1994 This information
notice requires no specific action or written response.
If you have any questions
about the information
in this notice, please contact the technical
contact listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Reactor Support Office of Nuclear Reactor Regulation
Technical
contact: Mark D. Pratt, NRR (301) 504-2701 Attachment:
List of Recently Issued NRC Information
Notices EELB Concurrence
obtained by M.D. Pratt*EELB:DE:NRR
MDPratt 12/22/93 D/DE , WHodge'V'W
01/12./94 DOCUMENT NAME: SC/EELB:DE:NRR
EWWeiss*C/OGCB:DORS:NRR
GHMarcus 12/22/93 MCCBSUPP.NEC
C/EELB:DE:NRR
CHBerlinger
/ /D/DORS:NRR
BKGrime'l 01/ /94X*OGCB:DORS:NRR
NECampbell
12/17/93*RPB: ADM Tech Ed 12/22/93 I
IN 93-XX December 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: Mark D. Pratt, NRR (301) 504-2701 Attachment:
List of Recently Issued NRC Information
Notices (FEELB Concurrence
obtained by M.D. Pratt ./A /Ie/w/Z3 EELB:DE:NRR
MDPrat 4 H&y D/DORS:NRR
BKGrimes 12/ /93 DOCUMENT NAME: SC/EELB:DE:NRR
EWWeiss #)C/OGCB:DORS:NRR
GHMarcusmf-I
12/2.2./93 MCCBSUPP.
NEC C/EELB:DE:NRR
CHBerl ingerg'l l OGCB:DORS:NRR
NECampbell
12/rP/93 3'RPB:ADM V Tech Ed (;/ lvq3 IN 93-XX December 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: Mark D. Pratt, NRR (301) 504-2701 Attachment:
List of Recently Issued NRC Information
Notices GEELB Concurrence
obtained by EELB:DE:NRR
SC/EELB:DE:NRR
MDPratt& EWWeisst)D/DORS:NRR
C/OGCB: DORS:NRI BKGrimes GHMarcus 12/ /93 12/ /93 DOCUMENT NAME: MCCBSUPP.NEC
M.D. Pratt C/EELB:DE:NRR
CHBerlingeiO
I1/OGCB:DORS:NRR
NECampbell
12/17/93 4.C.RPB:ADM TechEO R
Attaci t IN 93-26, Supp. 1 January 31, 1994 Page I of I LIST OF RECENTLY ISSUED NRC INFORMATION
NOTICES Informati0n, -Date of Notice No. Subject Issuance Issued to 94-07 93-85, Rev. 1 Solubility
Criteria for Liquid Effluent Releases to Sanitary Sewerage Under the Revised 10 CFR Part 20 Potential
Failure of Long-Term
Emergency Nitrogen Supply for the Automatic
Depressurization
System Valves Problems with X-Relays in DB- and DHP-Type Circuit Breakers Manu-factured by Westinghouse
Potential
Failure of Steam Generator
Tubes with Kinetically
Welded Sleeves Digital Integrated
Circuit Sockets with Intermittent
Contact Deficiencies
Identified
during Service Water System Operational
Performance
Inspections
Inoperability
of General Electric Magne-Blast
Breaker Because of Mis-alignment
of Close-Latch
Spring Turbine Blade Failures Caused by Torsional Excitation
from Electrical
System Disturbance
01/28/94 01/28/94 01/20/94 01/19/94 01/14/94 01/11/94 01/07/94 01/07/94 All byproduct
material and fuel cycle licensees
with the exception
of licensees authorized
solely for sealed sources.All holders of OLs or CPs for boiling water reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for pressurized
water reactors (PWRs).All NRC licensees
except licensed operators.
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.94-04 94-03 94-02 OL e Operating
License CP = Construction
Permit