Information Notice 2010-09, Importance of Understanding Circuit Breaker Control Power Indications: Difference between revisions
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==PURPOSE== | ==PURPOSE== | ||
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform addressees about circuit breaker control power indication issues that could result in degraded circuit breaker protection and contro The NRC expects that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problem Suggestions contained in this IN are not NRC requirements; therefore, no specific action or written response is require DESCRIPTION OF CIRCUMSTANCES On March 28, 2010, following an automatic reactor trip at H.B. Robinson Steam Electric Plant Unit 2, a non-safety related electrical circuit breaker did not automatically open to isolate an electrical fault because this breaker did not have control power to the trip circui The lack of control power was due to a faulty fuse assembly in the breaker's control power circui The licensee's corrective action program shows that the control power indicating lights on the front panel of the breaker had not been illuminated for approximately one yea Additional information is available in Preliminary Notification of Event PNO-II-10-002 dated March 29, 2010, and can be found on the NRC's public website in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML10088041 | The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform addressees about circuit breaker control power indication issues that could result in degraded circuit breaker protection and contro The NRC expects that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problem Suggestions contained in this IN are not NRC requirements; therefore, no specific action or written response is require | ||
==DESCRIPTION OF CIRCUMSTANCES== | |||
On March 28, 2010, following an automatic reactor trip at H.B. Robinson Steam Electric Plant Unit 2, a non-safety related electrical circuit breaker did not automatically open to isolate an electrical fault because this breaker did not have control power to the trip circui The lack of control power was due to a faulty fuse assembly in the breaker's control power circui The licensee's corrective action program shows that the control power indicating lights on the front panel of the breaker had not been illuminated for approximately one yea Additional information is available in Preliminary Notification of Event PNO-II-10-002 dated March 29, 2010, and can be found on the NRC's public website in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML10088041 | |||
==BACKGROUND== | ==BACKGROUND== | ||
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(1) IN 1991-78, "Status Indication of Control Power for Circuit Breakers Used in Safety-Related Applications," November 28, 1991 (ADAMS Accession No. ML082380373). (2) IN 2007-34, "Operating Experience Regarding Electrical Circuit Breakers," October 22, 2007 (ADAMS Accession No. ML072390061). | (1) IN 1991-78, "Status Indication of Control Power for Circuit Breakers Used in Safety-Related Applications," November 28, 1991 (ADAMS Accession No. ML082380373). (2) IN 2007-34, "Operating Experience Regarding Electrical Circuit Breakers," October 22, 2007 (ADAMS Accession No. ML072390061). | ||
The NRC issued IN 1991-78 to inform licensees of the importance of having control power for circuit breakers used in safety-related application This IN highlighted the importance of having control power indication for both safety-related and non-safety related application IN 2007-34 highlighted the importance of identifying possible causes for breaker problems including the lack of control power indicatio DISCUSSION Industry operating experience shows similar control power fuse issues where the indicating lights were either dim or not illuminate The loss or degradation of control power in circuit breakers can prevent the breaker from performing its design function of either opening or closing on deman Although there is no regulatory requirement for the functionality of the non-safety related breaker discussed in this IN, industry operating experience describes instances of technical specification required equipment being rendered inoperable due to similar circuit breaker control power issue A recent review of breaker control power operating experience has determined that the following items are important to ensure proper breaker operation: | The NRC issued IN 1991-78 to inform licensees of the importance of having control power for circuit breakers used in safety-related application This IN highlighted the importance of having control power indication for both safety-related and non-safety related application IN 2007-34 highlighted the importance of identifying possible causes for breaker problems including the lack of control power indicatio | ||
==DISCUSSION== | |||
Industry operating experience shows similar control power fuse issues where the indicating lights were either dim or not illuminate The loss or degradation of control power in circuit breakers can prevent the breaker from performing its design function of either opening or closing on deman Although there is no regulatory requirement for the functionality of the non-safety related breaker discussed in this IN, industry operating experience describes instances of technical specification required equipment being rendered inoperable due to similar circuit breaker control power issue A recent review of breaker control power operating experience has determined that the following items are important to ensure proper breaker operation: | |||
* the verification of control power indication for both safety-related and non-safety related circuit breakers during walkdowns | * the verification of control power indication for both safety-related and non-safety related circuit breakers during walkdowns | ||
* the potential impact on safety-related equipment resulting from a loss of control power to non-safety related circuit breakers when they fail to open to isolate a fault | * the potential impact on safety-related equipment resulting from a loss of control power to non-safety related circuit breakers when they fail to open to isolate a fault | ||
Revision as of 02:33, 19 February 2018
| ML101020184 | |
| Person / Time | |
|---|---|
| Issue date: | 04/14/2010 |
| Revision: | 0 |
| From: | Dorman D H, McGinty T J, Tracy G M NRC/NMSS/FCSS, Division of Construction Inspection and Operational Programs, Division of Policy and Rulemaking |
| To: | |
| Beaulieu, D P, NRR/DPR, 415-3243 | |
| References | |
| IN-10-009 | |
| Download: ML101020184 (4) | |
ML101020184 April 14, 2010 NRC INFORMATION NOTICE 2010-09: IMPORTANCE OF UNDERSTANDING CIRCUIT BREAKER CONTROL POWER INDICATIONS
ADDRESSEES
All holders of an operating license or construction permit for a nuclear power reactor issued under Title 10 of the Code of Federal Regulations (10 CFR) Part 50, "Domestic Licensing of Production and Utilization Facilities," except those who have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vesse All holders of or applicants for an early site permit, standard design certification, standard design approval, manufacturing license, or combined license issued under 10 CFR Part 52, "Licenses, Certifications, and Approvals for Nuclear Power Plants."
All holders of or applicants for a license for a fuel cycle facility issued pursuant to 10 CFR Part 70, "Domestic Licensing of Special Nuclear Material." All holders of or applicants for a certificate of compliance issued under 10 CFR Part 76,
"Certification of Gaseous Diffusion Plants." All holders of or applicants for a license for a uranium conversion facility issued pursuant to 10 CFR Part 40, "Domestic Licensing of Source Material."
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform addressees about circuit breaker control power indication issues that could result in degraded circuit breaker protection and contro The NRC expects that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problem Suggestions contained in this IN are not NRC requirements; therefore, no specific action or written response is require
DESCRIPTION OF CIRCUMSTANCES
On March 28, 2010, following an automatic reactor trip at H.B. Robinson Steam Electric Plant Unit 2, a non-safety related electrical circuit breaker did not automatically open to isolate an electrical fault because this breaker did not have control power to the trip circui The lack of control power was due to a faulty fuse assembly in the breaker's control power circui The licensee's corrective action program shows that the control power indicating lights on the front panel of the breaker had not been illuminated for approximately one yea Additional information is available in Preliminary Notification of Event PNO-II-10-002 dated March 29, 2010, and can be found on the NRC's public website in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML10088041
BACKGROUND
The NRC previously issued two INs related to circuit breaker control power issues:
(1) IN 1991-78, "Status Indication of Control Power for Circuit Breakers Used in Safety-Related Applications," November 28, 1991 (ADAMS Accession No. ML082380373). (2) IN 2007-34, "Operating Experience Regarding Electrical Circuit Breakers," October 22, 2007 (ADAMS Accession No. ML072390061).
The NRC issued IN 1991-78 to inform licensees of the importance of having control power for circuit breakers used in safety-related application This IN highlighted the importance of having control power indication for both safety-related and non-safety related application IN 2007-34 highlighted the importance of identifying possible causes for breaker problems including the lack of control power indicatio
DISCUSSION
Industry operating experience shows similar control power fuse issues where the indicating lights were either dim or not illuminate The loss or degradation of control power in circuit breakers can prevent the breaker from performing its design function of either opening or closing on deman Although there is no regulatory requirement for the functionality of the non-safety related breaker discussed in this IN, industry operating experience describes instances of technical specification required equipment being rendered inoperable due to similar circuit breaker control power issue A recent review of breaker control power operating experience has determined that the following items are important to ensure proper breaker operation:
- the verification of control power indication for both safety-related and non-safety related circuit breakers during walkdowns
- the potential impact on safety-related equipment resulting from a loss of control power to non-safety related circuit breakers when they fail to open to isolate a fault
CONTACT
This IN requires no specific action or written respons Please direct any questions about this matter to the technical contacts listed below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manage /RA/ /RA/
Timothy J. McGinty, Director Daniel H. Dorman, Director Division of Policy and Rulemaking Division of Fuel Cycle Safety and Safeguards Office of Nuclear Reactor Regulation Office of Nuclear Material Safety and Safeguards /RA/ By John Tappert For/
Glenn Tracy, Director Division of Construction Inspection and Operational Programs Office of New Reactors Technical Contacts: Jesse Robles, NRR Joseph Giantelli, NRR 301-415-2940 301-415-0504 E-mail: jesse.robles@nrc.gov E-mail: joseph.giantelli@nrc.gov Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under Electronic Reading Room/Document Collection
CONTACT
This IN requires no specific action or written respons Please direct any questions about this matter to the technical contacts listed below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manage /RA/ /RA/
Timothy J. McGinty, Director Daniel H. Dorman, Director Division of Policy and Rulemaking Division of Fuel Cycle Safety and Safeguards Office of Nuclear Reactor Regulation Office of Nuclear Material Safety and Safeguards /RA/ By John Tappert For/
Glenn Tracy, Director Division of Construction Inspection and Operational Programs Office of New Reactors Technical Contacts: Jesse Robles, NRR Joseph Giantelli, NRR 301-415-2940 301-415-0504 E-mail: jesse.robles@nrc.gov E-mail: joseph.giantelli@nrc.gov Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under Electronic Reading Room/Document Collection ADAMS Accession Number: ML101020184 TAC ME3754 OFFICE DIRS:IOEB DIRS:IOEB Tech Editor ABC:DIRS:IOEBD:NRR:DIRS BC:DE:EEB NAME JRobles JGiantelli KAKribbs EThomas FBrown GWilson DATE 04/14/10 04/14/10 04/12/10 e-mail 04/14/10 04/14/10 04/14/10 OFFICE LA:PGCB:NRR PM:PGCB:NRR BC:PGCB:NRR D:NMSS:DFCSSD:DCIP:NRO D:DPR:NRR NAME CHawes DBeaulieu MMurphy DDorman GTracy TMcGinty OFFICE 04/14/10 04/14/10 04/14/10 04/14/10 04/14/10 04/14/10 OFFICIAL RECORD COPY