Information Notice 1996-24, Preconditioning of Molded-Case Circuit Breakers Before Surveillance Testing: Difference between revisions
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{{#Wiki_filter:UNITED STATES | {{#Wiki_filter:UNITED STATES | ||
COMMISSION | NUCLEAR REGULATORY COMMISSION | ||
OFFICE OF NUCLEAR REACTOR REGULATION | |||
NOTICE 96-24: PRECONDITIONING | WASHINGTON, D.C. 20555-0001 April 25, 1996 NRC INFORMATION NOTICE 96-24: PRECONDITIONING OF MOLDED-CASE CIRCUIT BREAKERS | ||
BEFORE SURVEILLANCE TESTING | |||
TESTING | |||
==Addressees== | ==Addressees== | ||
All holders of operating | All holders of operating licenses or construction permits for nuclear power | ||
reactors. | |||
==Purpose== | ==Purpose== | ||
The U.S. Nuclear Regulatory | The U.S. Nuclear Regulatory Commission (NRC) is issuing this information | ||
Commission (NRC) is issuing this information | |||
notice to alert addressees to the detrimental effect that preconditioning of | |||
molded-case circuit breakers could have on the diagnostic validity of | |||
surveillance tests. It is expected that recipients will review this | |||
information for applicability to their facilities and consider actions, as | |||
appropriate, to avoid similar problbms. However, suggestions contained in | |||
this information notice are not NRC requirements; therefore, no specific | |||
action or written response is required. | |||
DescriDtion of Circumstances | |||
During an inspection at the Diablo Canyon Nuclear Power Plant (IR 50-275, | |||
323/94-27 dated December 21, 1994), NRC inspectors noted that the licensee | |||
preconditioned circuit breakers before performing surveillance testing. | |||
Before the overcurrent trip testing, Diablo Canyon staff exercised the circuit | |||
breakers by manually opening and closing them three times. The plant staff | |||
'did not record the as-found condition of the breakers in terms of unexercised | |||
trip currents and times. | |||
During another inspection at the South Texas Project (IR 50-498, 499/94-35 dated January 19, 1995), NRC inspectors noted that the licensee exercised | |||
breakers | similar circuit breakers manually at least five times before testing the | ||
overcurrent trip unit. | |||
Discussion | |||
A molded-case circuit breaker is one of the most widely used protective | |||
devices for electrical circuits at nuclear power plants. Its proper operation | |||
is essential for the protection and safe operation of plant electrical | |||
equipment. Many circuit breakers are continuously energized for long periods. | |||
Often they are in service for years and are rarely, if ever, called upon to | |||
perform a protective function. Nevertheless, when needed, they must rapidly | |||
isolate a faulted or overloaded circuit to prevent equipment damage. | |||
Therefore, for the safe operation of the electrical distribution system | |||
equipment of a nuclear power plant, it is important to periodically verify | |||
their continued reliability. | |||
.K | |||
VE uor~cEya-0OZ %6qZ 'I | |||
I | |||
K> | |||
IN 96-24 April 25, 1996 Periodic inspection and testing of circuit breakers in their as-found | |||
condition is an appropriate way of demonstrating the functional operability of | |||
the breaker and of detecting any degradation. However, the practice of | |||
preconditioning before testing (e.g., lubricating pivot points and manually | |||
cycling the breaker) defeats the purpose of the periodic test. Such | |||
preconditioning does not confirm continued operability between tests nor does | |||
it provide information on the condition of the circuit breaker for trending | |||
purposes. Testing some circuit breakers in the as-found condition can provide | |||
useful data on which to base decisions on surveillance intervals and the | |||
ability of the untested circuit breakers to perform their intended function. | |||
Since only a fraction of the circuit breakers are tested each refueling outage | |||
to justify the operability of the remaining circuit breakers, preconditioning | |||
before testing does not provide the expected assurance of the operability of | |||
remaining breakers which are not tested. By preconditioning circuit breakers, useful information may be lost because the breaker may not have been capable | |||
of performing its intended function without preconditioning. | |||
To correct this situation, Diablo Canyon Power Plant plans to revise the | |||
electrical maintenance procedure before the next surveillance test has to be | |||
performed. The revised procedures will state that electrical testing should | |||
be performed before any intentional manual exercising of the breakers, and to | |||
ensure that electrical testing on breakers with removable trip units is | |||
performed before removing the trip unit. | |||
Some plants have older technical specification bases that cite National | |||
Electrical Manufacturers Association (NEMA) Standard AB 2-1980. This version | |||
of the standard specifies mechanical cycling of circuit breakers prior to | |||
electrical testing. In later versions of this standard, this procedure was | |||
deleted. There appears to be no valid technical need for mechanical cycling | |||
prior to electrical surveillance testing. | |||
The NRC has issued other generic communications on molded-case circuit breaker | |||
applications and testing: NRC Information Notice (IN) 92-51, and its | |||
Supplement 1, "Misapplication and Inadequate Testing of Molded-Case Circuit | |||
Breakers;" IN 93-26, "Grease Solidification Causes Molded Case Circuit Breaker | |||
Failure to Close;" and IN 93-64, "Periodic Testing and Preventive Maintenance | |||
of Molded-Case Circuit Breakers." | |||
If I | |||
IN 96-24 April 25, 1996 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. /a | |||
L.." | |||
Brian K. Grimes, Acting Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Sikhindra Mitra, NRR | |||
(301) 415-2783 Internet:skml@nrc.gov | |||
Steve Alexander, NRR | |||
(301) 415-2995 Internet:sda@nrc.gov | |||
Christopher Myers, RIV | |||
(817) 860-8144 Internet:cjm@nrc.gov | |||
Attachment: List of Recently Issued NRC Information Notices | |||
-tw@ / "Y | |||
K | |||
Attachment | |||
IN 96-24 April 25, 1996 LIST OF RECENTLY ISSUED | |||
NRC INFORMATION NOTICES | |||
Information Date of | |||
Notice No. Subject Issuance Issued to | |||
96-23 Fires in Emergency Diesel 04/22/96 All holders of OLs or CPs | |||
Generator Exciters During for nuclear power reactors | |||
Operation Following Unde- tected Fuse Blowing | |||
96-22 Improper Equipment Set- 04/11/96 All holders of OLs or CPs | |||
tings Due to the Use of for nuclear power reactors | |||
Nontemperature-Compensated | |||
Test Equipment | |||
96-21 Safety Concerns Related 04/10/96 All U.S. NRC Medical to the | |||
authorized | to the Design of the Door Licensees authorized to use | ||
Interlock Circuit on brachytherapy sources in | |||
Nucletron High-Dose Rate high- and pulsed-dose-rate | |||
remote afterloaders | and Pulsed Dose Rate remote afterloaders | ||
Remote Afterloading | |||
Brachytherapy Devices | |||
96-20 Demonstration of Associ- 04/04/96 All industrial radiography | |||
and radiography | ated Equipment Compliance licensees and radiography | ||
equipment | with 10 CFR 34.20 equipment manufacturers | ||
96-19 Failure of Tone Alert 04/02/96 All holders of OLs or CPs | |||
Radios to Activate When for nuclear power reactors | |||
Receiving a Shortened | |||
Activation Signal | |||
96-18 Compliance with 10 CFR 03/25/96 All material licensees | |||
Part 20 for Airborne authorized to possess and | |||
Thorium use thorium in unsealed | |||
form | |||
95-03 Loss of Reactor Coolant 03/25/96 All holders of OLs or CPs | |||
Supp. 1 Inventory and Potential for PWR power plants | |||
Loss of Emergency Mitiga- tion Functions While in a | |||
Shutdown Condition | |||
= | OL = Operating License | ||
CP - Construction Permit | |||
K2 2 IN 96-24 April 25, 1996 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. | |||
original signed by | |||
Brian K. Grimes, Acting Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Sikhindra Mitra, NRR | |||
(301) 415-2783 Internet:skml@nrc.gov | |||
Steve Alexander, NRR | |||
(301) 415-2995 Internet:sda@nrc.gov | |||
Christopher Myers, RIV | |||
(817) 860-8144 Internet:cjm@nrc.gov | |||
Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 96-24.IN Tech Editor reviewed 9/21/95 To receive a copy of this document, Indicate In the box: 'C' - Copy without enclosures 'E" = Copy with sncloRre -l = No copy | |||
OFFICE Contacts C IEELB | |||
NAME CMyers * JCalvo * AChatfee s | |||
SMitra * / | |||
SAlexander* 7 , | |||
DATE 4/22/96 4/15/96 4/22/96 4/LT/96 OFFICIAL RECORD COPY | |||
IN 96-XX | |||
April XX, 1996 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. | |||
Dennis M. Crutchfield, Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Sikhindra Mitra, NRR Christopher Myers, RIV | |||
(301) 415-2783 (817) 860-8144 Internet: skmlnrc.gov Internet: cjm@nrc.gov | |||
Steve Alexander, NRR | |||
(301) 415-2995 Internet: sda@nrc.gov | |||
Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN Tech Editor reviewed 9/21/95 To receive a copy of this document. Indicate In the box: 'C' - Copy without enclosures fEw - Copy with enclosures 'N' - No copy | |||
OFFICE IContacts C/EELB D/DRPI lI | |||
NAME CMyers * JCalvo * AChaffee DCrutchfield | |||
SMitra * | |||
SAlexanderLnfi_ | |||
DATE 4 /15/96 7' 4/15/96 4/ /96 4/ /96 | |||
. - - - - - - - | |||
UICLIAL KECOKR COPY | |||
,44 | |||
I 1 i | |||
<-' IN 96-XX | |||
April XX, 1996 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. | |||
Dennis M. Crutchfield, Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Sikhindra Mitra, NRR Christopher Myers, RIV | |||
(301) 415-2783 (817) 860-8144 Internet: skmlnrc.gov Internet: cjm~nrc.gov | |||
Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN Tech Editor reviewed 9/21/95 To receive a copy of this document, Indicate In the box: 'C' - Copy without enclosures 'E' - Copy with enclosures 'No = No copy | |||
lOFFICE Contacts I C/EELB l C/PECB I DRPM I | |||
NAME CMyers * JCalvo * AChaffee DCrutchfield | |||
SMitra * | |||
DATE 4 /I5/96 4/11 /96 4/ 4/ /96 OFFICIAL RECORD COPY | |||
IN 96-XX | |||
April XX, 1996 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. | |||
Dennis M. Crutchfield, Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Christopher Myers, RIV | |||
(817) 860-8144 Sikhindra Mitra, NRR | |||
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN Tech Editor reviewed 9/21/95 To receive a copy of this document. Indicate In the box: wCw = Copy without enclosures 'E" - Copy with enclosures 'N'= No copy | |||
OFFICE Contacts C/EELB I | |||
NAME Myers JCalvoJy r AChaffee DCrutchfield | |||
I ~SMi tra_ _ _ _ _ _ _ | |||
DATE 4 /16796 4/ I7/96 4/ /96 4/ /96 OFFICIAL RECORD COPY | |||
IN 96-XX | |||
April xx, 1996 This information notice requires no specific action or written response. If | |||
you have any questions about the information in this notice, please contact | |||
Office of | one of the technical contacts listed below or the appropriate Office of | ||
Nuclear Reactor Regulation (NRR) project manager. | |||
Dennis M. Crutchfield, Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Tom Westerman, RIV Christopher Myers, RIV | |||
(817) 860-8145 (817) 860-8144 Stephen Alexander, NRR Sikhindra Mitra, NRR | |||
(301) 415-2995 (301) 415-2783 Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN * . See previous concurrence | |||
* wprs | |||
'N' = No copy | T 5 .LL.1. .I i *k.hn,.. tC =-Cnnu without enclosures, | ||
........................... =E' CoDv with enclosures 'N' = No copy | |||
rcv r^uumn, juciva lwi'Jw. -r,. | |||
OFFICE RIV liE RIV E lRIV l E RIV E PSIB:DISP E | |||
NAME LTWesterman A CMyers k _ TP Gwyn* SAlexander | |||
l EE:DE E SC:EELB:DE | DATE I1/ g/95 t /,/95 / /95 01/25/95 / /95 OFFICE TECH ED N SC:SIB:DISP l EE:DE E SC:EELB:DE E C:EELB:DEl E | ||
NAME WRSanders SKMitra 't ASGill* JACalvo* | |||
DATE 109/21/95* / /95 41,1/2o%96 I/Y.1 09/21/95 9/27/95 OFFICE IPECB:DRPM PECB:DRPM PECB:DRPM I C:PECB:DRPM l D:DRPM | |||
NAME JTKoshy EFGoodwin* AChaffee DMCrutchfield | |||
DATE IJ/f/96 10/04/95 I /95 /95 /95 OFFICIAL RECORD COPY | |||
/ /95 | |||
IN 96-XX | |||
January xx, 1995 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. | |||
Dennis M. Crutchfield, Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Tom Westerman, RIV Christopher Myers, RIV | |||
(817) 860-8145 (817) 860-8144 Stephen Alexander, NRR Sikhindra Mitra, NRR | |||
(301) 415-2995 (301) 415-2783 Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN * . See previous concurrence | |||
To receive a copv ol this document. indicate Inthe box: C - Coov without enclosures . | |||
-E' CoDV with enclosures "N" - No coDY | |||
lOFFICE RI Tf RI E I BDS _I | |||
NAME TWesterman CMyers _ _ _ TP Gwyn* SAl exander | |||
DATE / /95 1 I / /9 IL/5 01_/25/95 / /95 OFFICE lTECH ED N SC:SIB:DISP E EELB:DE E SC:EELB:DE I E lC:EELB:DEl E | |||
NAME l RSanders SKMi tra ASGill* JJACalvo* | |||
DATE l09/21/95* / /95 I / 1/96 09/21/95 9/27/95 OFFICE JIPECB:DRPM PECB:DRPM I C:PECB:DRPMl D:DRPM | |||
* | NAME TKoshy EFGoodwin* AChaffee DMCrutchfi eld | ||
DATE I /oF/9 _ 10/04/95 / /95 / /95 / /95 OFFICIAL RECORD COPY | |||
/ /95 | |||
IK 'I | |||
IN 95-XX | |||
September xx, 1995 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. | |||
Dennis M. Crutchfield, Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical contacts: Tom Westerman, RIV Christopher Myers, RIV | |||
(817) 860-8145 (817) 860-8144 Stephen Alexander, NRR Sikhindra Mitra, NRR | |||
(301) 415-2995 (301) 415-2783 Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN * * See previous concurrence | |||
Te raclva a etonw of thb document Indicate hI Om box: 'C' - Copv without enclosures 'E - Copy with enclosures 'N- - No copy | |||
OFFICE R E RIV E R RIV E PSIB:DISP E | |||
NAME TWesterman c CMyers / T/5 6_ n SAlexander | |||
_ _w | |||
DATE I /Teean/95 jC/1y/95 / /95 _ T/ZS/95 I /95 OFFICE TECH ED N SC:SIB:DISP l DEE E SC:EELB:DE E C:EELB:DE E | |||
NAME RSanders SKMitra* ASGill* JACalvo* | |||
DATE 09/21/95* / /95 09/20/95 09/21/95 / /95 OFFICE PECB:DRPM I E PECB:DRPM / l-JLIPEIBhRPM IZC:PECB:DRPM ID:DRPM | |||
NAME TKoshy EFGoodwin RJK AChaffee DMCrutchfield | |||
DATE 9/26/95 y 95 V // /95 / /95 OFFICIAL RECORD COPY | |||
IN 95-XX | |||
September xx, 1995 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, Deputy Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical Contacts: Tom Westerman, RIV | |||
(817) 860-8145 Christopher Myers, RIV | |||
(817) 860-8144 Stephen Alexander, NRR | |||
(301) 415-2995 Sikhindra Mitra, NRR | |||
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN * , See previous concurrence | |||
To receive a copy of this document. Indicate In the box: 'C' Copy without enclosures E' - Copy with enclosures N - No copy | |||
OFFICE RIY I E RIY E RIV | |||
RIYE E PSIB:DISP E | |||
NAME TWesterman CMyers ____ _ SAlexander | |||
DATE / /LE95 / /95 I /95 /95 / /95 OFFICE TECH ED I N SC:SIB:DISP E EELB:DE I E SC:EELB:DEl E C:EELB:DEI E | |||
NAME RSanders SKMitra* ASGill* JACalvo I/ACj | |||
DATE 09/21/95* / /95 09/20/95 09/21/95 f /17/95 qI~d'3 OFFICE PECB:DRPM l C:PECB:DRPM l DD:DRPM | |||
NAME AChaffee BKGrimes | |||
DATE I /95 / /95 l// | |||
OFFICIAL RECORD COPY | |||
i | |||
IN 95-XX | |||
August XX, 1995 one of the technical contacts listed below or the appropriate Office of | |||
Nuclear Reactor Regulation (NRR) project manager. | |||
Brian K. Grimes, Deputy Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical Contacts: Tom Westerman, RIV | |||
(817) 860-8145 Christopher Myers, RIV | |||
(817) 860-8144 Stephen Alexander, NRR | |||
(301) 415-2995 Sikhindra Mitra, NRR | |||
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN * . See previous concurrence | |||
To rAceivA a Cf nv donument. indicate Inthe box: 'C' | |||
thids - Coov without enclosures 'E' - Copy with enclosures 'N' . No copy | |||
l1El R EE RIV | |||
RE I E lPSIB:DISP I E | |||
OFFICE | |||
NAME | |||
DATE | |||
RIV | |||
TWesterman | |||
/ /95 t | |||
CMyers | |||
I /95 ISAlexander | |||
/ /95 /95 /95 OFFICE TECH ED N SC:SIB:DISP I E EELB:DE E SC:EELB-DE E C:EELB:DEl E | |||
NAME BCalure SKMitra YOM& ASGill t JACalvo | |||
DATE 08/03/95* j-/ /95 / O/95 /04/95 / /95 OFFICE PECB:DRPM l C:PECB:DRPMT DD:DRPM | |||
NAME AChaffee BKGrimes | |||
DATE I /95 / /95 / /95 OFFICIAL RECORD COPY | |||
DATE | |||
K-/ | |||
IN 95-XX | |||
August XX, 1995 one of the technical contacts listed below or the appropriate Office of | |||
Nuclear Reactor Regulation (NRR) project manager. | |||
Brian K. Grimes, Deputy Director | |||
Division of Reactor Program Management | |||
Office of Nuclear Reactor Regulation | |||
Technical Contacts: Tom Westerman, RIV | |||
(817) 860-8145 Christopher Myers, RIV | |||
(817) 860-8144 Stephen Alexander, NRR | |||
(301). 415-2995 Sikhindra Mitra, NRR | |||
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices | |||
DOCUMENT NAME: 95-XX.IN * = See previous concurrence | |||
To receive a copy of this document. Indicate In the box: NCR - Copy without endosurms wEd - Copy with oncosurss rW- No copy | |||
OFFICE RIV I E RIY E RIV E RIV I E PSIB:DISP I E | |||
NAME TWesterman CMyers I jSAlexander | |||
DATE / /95 / /95 1/. /95 /95 / /95 OFFICE TECH ED N SC:SIB:DISP I E EELB:DE E SC:EELB:DE E C:EELB:DEI E | |||
I | NAME BCalure K54a" 1SKMitra ASGill JACalvo I | ||
DATE 08/03/95* gf(gfIq / /95 / /95 /95 / /95 OFFICE PECB:DRPM C:PECB:DRPM DD:DRPM | |||
DATE / /95 / /95 | |||
NAME | |||
DATE/ /95 1 | |||
1AChaffee | |||
/ /95 BKGrimes | |||
/ /95 II | |||
_ l | |||
OFFICIAL RECORD COPY}} | |||
{{Information notice-Nav}} | {{Information notice-Nav}} |
Latest revision as of 04:37, 24 November 2019
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001 April 25, 1996 NRC INFORMATION NOTICE 96-24: PRECONDITIONING OF MOLDED-CASE CIRCUIT BREAKERS
BEFORE SURVEILLANCE TESTING
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 detrimental effect that preconditioning of
molded-case circuit breakers could have on the diagnostic validity of
surveillance tests. It is expected that recipients will review this
information for applicability to their facilities and consider actions, as
appropriate, to avoid similar problbms. However, suggestions contained in
this information notice are not NRC requirements; therefore, no specific
action or written response is required.
DescriDtion of Circumstances
During an inspection at the Diablo Canyon Nuclear Power Plant (IR 50-275,
323/94-27 dated December 21, 1994), NRC inspectors noted that the licensee
preconditioned circuit breakers before performing surveillance testing.
Before the overcurrent trip testing, Diablo Canyon staff exercised the circuit
breakers by manually opening and closing them three times. The plant staff
'did not record the as-found condition of the breakers in terms of unexercised
trip currents and times.
During another inspection at the South Texas Project (IR 50-498, 499/94-35 dated January 19, 1995), NRC inspectors noted that the licensee exercised
similar circuit breakers manually at least five times before testing the
overcurrent trip unit.
Discussion
A molded-case circuit breaker is one of the most widely used protective
devices for electrical circuits at nuclear power plants. Its proper operation
is essential for the protection and safe operation of plant electrical
equipment. Many circuit breakers are continuously energized for long periods.
Often they are in service for years and are rarely, if ever, called upon to
perform a protective function. Nevertheless, when needed, they must rapidly
isolate a faulted or overloaded circuit to prevent equipment damage.
Therefore, for the safe operation of the electrical distribution system
equipment of a nuclear power plant, it is important to periodically verify
their continued reliability.
.K
VE uor~cEya-0OZ %6qZ 'I
I
K>
IN 96-24 April 25, 1996 Periodic inspection and testing of circuit breakers in their as-found
condition is an appropriate way of demonstrating the functional operability of
the breaker and of detecting any degradation. However, the practice of
preconditioning before testing (e.g., lubricating pivot points and manually
cycling the breaker) defeats the purpose of the periodic test. Such
preconditioning does not confirm continued operability between tests nor does
it provide information on the condition of the circuit breaker for trending
purposes. Testing some circuit breakers in the as-found condition can provide
useful data on which to base decisions on surveillance intervals and the
ability of the untested circuit breakers to perform their intended function.
Since only a fraction of the circuit breakers are tested each refueling outage
to justify the operability of the remaining circuit breakers, preconditioning
before testing does not provide the expected assurance of the operability of
remaining breakers which are not tested. By preconditioning circuit breakers, useful information may be lost because the breaker may not have been capable
of performing its intended function without preconditioning.
To correct this situation, Diablo Canyon Power Plant plans to revise the
electrical maintenance procedure before the next surveillance test has to be
performed. The revised procedures will state that electrical testing should
be performed before any intentional manual exercising of the breakers, and to
ensure that electrical testing on breakers with removable trip units is
performed before removing the trip unit.
Some plants have older technical specification bases that cite National
Electrical Manufacturers Association (NEMA) Standard AB 2-1980. This version
of the standard specifies mechanical cycling of circuit breakers prior to
electrical testing. In later versions of this standard, this procedure was
deleted. There appears to be no valid technical need for mechanical cycling
prior to electrical surveillance testing.
The NRC has issued other generic communications on molded-case circuit breaker
applications and testing: NRC Information Notice (IN) 92-51, and its
Supplement 1, "Misapplication and Inadequate Testing of Molded-Case Circuit
Breakers;" IN 93-26, "Grease Solidification Causes Molded Case Circuit Breaker
Failure to Close;" and IN 93-64, "Periodic Testing and Preventive Maintenance
of Molded-Case Circuit Breakers."
If I
IN 96-24 April 25, 1996 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. /a
L.."
Brian K. Grimes, Acting Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Sikhindra Mitra, NRR
(301) 415-2783 Internet:skml@nrc.gov
Steve Alexander, NRR
(301) 415-2995 Internet:sda@nrc.gov
Christopher Myers, RIV
(817) 860-8144 Internet:cjm@nrc.gov
Attachment: List of Recently Issued NRC Information Notices
-tw@ / "Y
K
Attachment
IN 96-24 April 25, 1996 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information Date of
Notice No. Subject Issuance Issued to
96-23 Fires in Emergency Diesel 04/22/96 All holders of OLs or CPs
Generator Exciters During for nuclear power reactors
Operation Following Unde- tected Fuse Blowing
96-22 Improper Equipment Set- 04/11/96 All holders of OLs or CPs
tings Due to the Use of for nuclear power reactors
Nontemperature-Compensated
Test Equipment
96-21 Safety Concerns Related 04/10/96 All U.S. NRC Medical to the
to the Design of the Door Licensees authorized to use
Interlock Circuit on brachytherapy sources in
Nucletron High-Dose Rate high- and pulsed-dose-rate
and Pulsed Dose Rate remote afterloaders
Remote Afterloading
Brachytherapy Devices
96-20 Demonstration of Associ- 04/04/96 All industrial radiography
ated Equipment Compliance licensees and radiography
with 10 CFR 34.20 equipment manufacturers
96-19 Failure of Tone Alert 04/02/96 All holders of OLs or CPs
Radios to Activate When for nuclear power reactors
Receiving a Shortened
Activation Signal
96-18 Compliance with 10 CFR 03/25/96 All material licensees
Part 20 for Airborne authorized to possess and
Thorium use thorium in unsealed
form
95-03 Loss of Reactor Coolant 03/25/96 All holders of OLs or CPs
Supp. 1 Inventory and Potential for PWR power plants
Loss of Emergency Mitiga- tion Functions While in a
Shutdown Condition
OL = Operating License
CP - Construction Permit
K2 2 IN 96-24 April 25, 1996 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.
original signed by
Brian K. Grimes, Acting Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Sikhindra Mitra, NRR
(301) 415-2783 Internet:skml@nrc.gov
Steve Alexander, NRR
(301) 415-2995 Internet:sda@nrc.gov
Christopher Myers, RIV
(817) 860-8144 Internet:cjm@nrc.gov
Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 96-24.IN Tech Editor reviewed 9/21/95 To receive a copy of this document, Indicate In the box: 'C' - Copy without enclosures 'E" = Copy with sncloRre -l = No copy
OFFICE Contacts C IEELB
NAME CMyers * JCalvo * AChatfee s
SMitra * /
SAlexander* 7 ,
DATE 4/22/96 4/15/96 4/22/96 4/LT/96 OFFICIAL RECORD COPY
IN 96-XX
April XX, 1996 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.
Dennis M. Crutchfield, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Sikhindra Mitra, NRR Christopher Myers, RIV
(301) 415-2783 (817) 860-8144 Internet: skmlnrc.gov Internet: cjm@nrc.gov
Steve Alexander, NRR
(301) 415-2995 Internet: sda@nrc.gov
Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN Tech Editor reviewed 9/21/95 To receive a copy of this document. Indicate In the box: 'C' - Copy without enclosures fEw - Copy with enclosures 'N' - No copy
OFFICE IContacts C/EELB D/DRPI lI
NAME CMyers * JCalvo * AChaffee DCrutchfield
SMitra *
SAlexanderLnfi_
DATE 4 /15/96 7' 4/15/96 4/ /96 4/ /96
. - - - - - - -
UICLIAL KECOKR COPY
,44
I 1 i
<-' IN 96-XX
April XX, 1996 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.
Dennis M. Crutchfield, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Sikhindra Mitra, NRR Christopher Myers, RIV
(301) 415-2783 (817) 860-8144 Internet: skmlnrc.gov Internet: cjm~nrc.gov
Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN Tech Editor reviewed 9/21/95 To receive a copy of this document, Indicate In the box: 'C' - Copy without enclosures 'E' - Copy with enclosures 'No = No copy
lOFFICE Contacts I C/EELB l C/PECB I DRPM I
NAME CMyers * JCalvo * AChaffee DCrutchfield
SMitra *
DATE 4 /I5/96 4/11 /96 4/ 4/ /96 OFFICIAL RECORD COPY
IN 96-XX
April XX, 1996 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.
Dennis M. Crutchfield, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Christopher Myers, RIV
(817) 860-8144 Sikhindra Mitra, NRR
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN Tech Editor reviewed 9/21/95 To receive a copy of this document. Indicate In the box: wCw = Copy without enclosures 'E" - Copy with enclosures 'N'= No copy
OFFICE Contacts C/EELB I
NAME Myers JCalvoJy r AChaffee DCrutchfield
I ~SMi tra_ _ _ _ _ _ _
DATE 4 /16796 4/ I7/96 4/ /96 4/ /96 OFFICIAL RECORD COPY
IN 96-XX
April xx, 1996 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.
Dennis M. Crutchfield, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Tom Westerman, RIV Christopher Myers, RIV
(817) 860-8145 (817) 860-8144 Stephen Alexander, NRR Sikhindra Mitra, NRR
(301) 415-2995 (301) 415-2783 Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN * . See previous concurrence
- wprs
T 5 .LL.1. .I i *k.hn,.. tC =-Cnnu without enclosures,
........................... =E' CoDv with enclosures 'N' = No copy
rcv r^uumn, juciva lwi'Jw. -r,.
OFFICE RIV liE RIV E lRIV l E RIV E PSIB:DISP E
NAME LTWesterman A CMyers k _ TP Gwyn* SAlexander
DATE I1/ g/95 t /,/95 / /95 01/25/95 / /95 OFFICE TECH ED N SC:SIB:DISP l EE:DE E SC:EELB:DE E C:EELB:DEl E
NAME WRSanders SKMitra 't ASGill* JACalvo*
DATE 109/21/95* / /95 41,1/2o%96 I/Y.1 09/21/95 9/27/95 OFFICE IPECB:DRPM PECB:DRPM PECB:DRPM I C:PECB:DRPM l D:DRPM
NAME JTKoshy EFGoodwin* AChaffee DMCrutchfield
DATE IJ/f/96 10/04/95 I /95 /95 /95 OFFICIAL RECORD COPY
IN 96-XX
January xx, 1995 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.
Dennis M. Crutchfield, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Tom Westerman, RIV Christopher Myers, RIV
(817) 860-8145 (817) 860-8144 Stephen Alexander, NRR Sikhindra Mitra, NRR
(301) 415-2995 (301) 415-2783 Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN * . See previous concurrence
To receive a copv ol this document. indicate Inthe box: C - Coov without enclosures .
-E' CoDV with enclosures "N" - No coDY
lOFFICE RI Tf RI E I BDS _I
NAME TWesterman CMyers _ _ _ TP Gwyn* SAl exander
DATE / /95 1 I / /9 IL/5 01_/25/95 / /95 OFFICE lTECH ED N SC:SIB:DISP E EELB:DE E SC:EELB:DE I E lC:EELB:DEl E
NAME l RSanders SKMi tra ASGill* JJACalvo*
DATE l09/21/95* / /95 I / 1/96 09/21/95 9/27/95 OFFICE JIPECB:DRPM PECB:DRPM I C:PECB:DRPMl D:DRPM
NAME TKoshy EFGoodwin* AChaffee DMCrutchfi eld
DATE I /oF/9 _ 10/04/95 / /95 / /95 / /95 OFFICIAL RECORD COPY
IK 'I
IN 95-XX
September xx, 1995 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.
Dennis M. Crutchfield, Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical contacts: Tom Westerman, RIV Christopher Myers, RIV
(817) 860-8145 (817) 860-8144 Stephen Alexander, NRR Sikhindra Mitra, NRR
(301) 415-2995 (301) 415-2783 Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN * * See previous concurrence
Te raclva a etonw of thb document Indicate hI Om box: 'C' - Copv without enclosures 'E - Copy with enclosures 'N- - No copy
OFFICE R E RIV E R RIV E PSIB:DISP E
NAME TWesterman c CMyers / T/5 6_ n SAlexander
_ _w
DATE I /Teean/95 jC/1y/95 / /95 _ T/ZS/95 I /95 OFFICE TECH ED N SC:SIB:DISP l DEE E SC:EELB:DE E C:EELB:DE E
NAME RSanders SKMitra* ASGill* JACalvo*
DATE 09/21/95* / /95 09/20/95 09/21/95 / /95 OFFICE PECB:DRPM I E PECB:DRPM / l-JLIPEIBhRPM IZC:PECB:DRPM ID:DRPM
NAME TKoshy EFGoodwin RJK AChaffee DMCrutchfield
DATE 9/26/95 y 95 V // /95 / /95 OFFICIAL RECORD COPY
IN 95-XX
September xx, 1995 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, Deputy Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical Contacts: Tom Westerman, RIV
(817) 860-8145 Christopher Myers, RIV
(817) 860-8144 Stephen Alexander, NRR
(301) 415-2995 Sikhindra Mitra, NRR
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN * , See previous concurrence
To receive a copy of this document. Indicate In the box: 'C' Copy without enclosures E' - Copy with enclosures N - No copy
OFFICE RIY I E RIY E RIV
RIYE E PSIB:DISP E
NAME TWesterman CMyers ____ _ SAlexander
DATE / /LE95 / /95 I /95 /95 / /95 OFFICE TECH ED I N SC:SIB:DISP E EELB:DE I E SC:EELB:DEl E C:EELB:DEI E
NAME RSanders SKMitra* ASGill* JACalvo I/ACj
DATE 09/21/95* / /95 09/20/95 09/21/95 f /17/95 qI~d'3 OFFICE PECB:DRPM l C:PECB:DRPM l DD:DRPM
NAME AChaffee BKGrimes
DATE I /95 / /95 l//
OFFICIAL RECORD COPY
i
IN 95-XX
August XX, 1995 one of the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.
Brian K. Grimes, Deputy Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical Contacts: Tom Westerman, RIV
(817) 860-8145 Christopher Myers, RIV
(817) 860-8144 Stephen Alexander, NRR
(301) 415-2995 Sikhindra Mitra, NRR
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN * . See previous concurrence
To rAceivA a Cf nv donument. indicate Inthe box: 'C'
thids - Coov without enclosures 'E' - Copy with enclosures 'N' . No copy
l1El R EE RIV
RE I E lPSIB:DISP I E
OFFICE
NAME
DATE
RIV
TWesterman
/ /95 t
CMyers
I /95 ISAlexander
/ /95 /95 /95 OFFICE TECH ED N SC:SIB:DISP I E EELB:DE E SC:EELB-DE E C:EELB:DEl E
NAME BCalure SKMitra YOM& ASGill t JACalvo
DATE 08/03/95* j-/ /95 / O/95 /04/95 / /95 OFFICE PECB:DRPM l C:PECB:DRPMT DD:DRPM
NAME AChaffee BKGrimes
DATE I /95 / /95 / /95 OFFICIAL RECORD COPY
K-/
IN 95-XX
August XX, 1995 one of the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.
Brian K. Grimes, Deputy Director
Division of Reactor Program Management
Office of Nuclear Reactor Regulation
Technical Contacts: Tom Westerman, RIV
(817) 860-8145 Christopher Myers, RIV
(817) 860-8144 Stephen Alexander, NRR
(301). 415-2995 Sikhindra Mitra, NRR
(301) 415-2783 Attachment: List of Recently Issued NRC Information Notices
DOCUMENT NAME: 95-XX.IN * = See previous concurrence
To receive a copy of this document. Indicate In the box: NCR - Copy without endosurms wEd - Copy with oncosurss rW- No copy
OFFICE RIV I E RIY E RIV E RIV I E PSIB:DISP I E
NAME TWesterman CMyers I jSAlexander
DATE / /95 / /95 1/. /95 /95 / /95 OFFICE TECH ED N SC:SIB:DISP I E EELB:DE E SC:EELB:DE E C:EELB:DEI E
NAME BCalure K54a" 1SKMitra ASGill JACalvo I
DATE 08/03/95* gf(gfIq / /95 / /95 /95 / /95 OFFICE PECB:DRPM C:PECB:DRPM DD:DRPM
NAME
DATE/ /95 1
1AChaffee
/ /95 BKGrimes
/ /95 II
_ l
OFFICIAL RECORD COPY