Information Notice 2009-10, Official Exhibit - NYS000019-00-BD01- NRC Information Notice 2009-10, Transformers Failures - Recent Operating Experience (Jul. 7, 2009) (NRC in 2009-10)

Official Exhibit - NYS000019-00-BD01- NRC Information Notice 2009-10, Transformers Failures - Recent Operating Experience (Jul. 7, 2009) (NRC in 2009-10)

ML12334A490
Person / Time
Site:	Indian Point
Issue date:	07/07/2009
From:	Dan Dorman, Mcginty T NRC/NMSS/FCSS, Division of Policy and Rulemaking
To:	Atomic Safety and Licensing Board Panel
SECY RAS
References
RAS 21523, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 IN-09-010
Download: ML12334A490 (4)

United States Nuclear Regulatory Commission Official Hearing Exhibit NYS000019 Entergy Nuclear Operations, Inc.

In the Matter of:

(Indian Point Nuclear Generating Units 2 and 3) Submitted: December 12, 2011 u....~p..p. REG(J~)- ASLBP #: 07-858-03-LR-BD01

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Docket #: 05000247 l 05000286

~ 0 Exhibit #: NYS000019-00-BD01 Identified: 10/15/2012

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Admitted: 10/15/2012 Withdrawn:

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Other:

Stricken:

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS

WASHINGTON, DC 20555-0001 July 7,2009 NRC INFORMATION NOTICE 2009-10: TRANSFORM ER FAI LU RES-RECENT

OPERATI NG EXPERI ENCE

ADDRESSEES

All holders of operating licenses for nuclear power reactors under the provisions of Title 10 of

the Code of Federal Regulations (10 CFR) Part 50, "Domestic Licensing of Production and

Utilization Facilities," except those who have ceased operations and have certified that fuel has

been permanently removed from the reactor vessel. All holders of licenses or certificates of fuel

cycle facilities. All holders of and applicants for nuclear power plant construction permits under

the provisions of 10 CFR Part 50. All holders of licenses or certificates for fuel cycle facilities.

PURPOSE

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform

addressees of recent operating experience involving failures of large transformers. The NRC

expects 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 IN

are not NRC requirements; therefore, no specific action or written response is required.

DESCRIPTION OF CIRCUMSTANCES

For several years, available industry operating experience has indicated an increasing trend in

transformer failures, and has provided recommendations to reduce the chances of failure.

Improved preventive maintenance and monitoring practices have helped to identify some

problems before they developed to the point of failure, but the number of large transformers

events has not decreased and in fact continues to rise. The following are relatively recent

examples involving main power transformers:

• Indian Point, Unit 3-0n April 6,2007, while operating at 92-percent power, a fault

occurred on the No. 31 main transformer resulting in an automatic reactor trip and

transformer fire. Licensee Event Report (LER) 50-286/2007-002, which can be found on

the NRC's public Web site using Agencywide Documents Access and Management

System (ADAMS) Accession No. ML071620122, provides additional information.

• River Bend Station-On May 4,2007, an unplanned manual reactor scram was initiated

following the loss of cooling on the No.2 main transformer (see LER 50-458/2007-002, ADAMS Accession No. ML071840161, for more information).

• Grand Gulf Nuclear Station-On January 12, 2008, a manual reactor scram was initiated

following a loss of cooling to the main transformers (see LER 50-416/2008-001, ADAMS

Accession No. ML080700702, for more information).

M L090540218 OAG 10000526_000001 * Limerick Generating Station, Unit 2-0n February 1, 2008, a low voltage bushing

connection failed on the 2A main transformer resulting in a turbine trip and reactor

scram.

• Diablo Canyon, Unit 2-0n August 16,2008, an automatic reactor trip occurred resulting

from the failure of the main electrical transformer C phase. Plant operators

subsequently declared a Notification of Unusual Event due to an observed fire at the

C phase transformer (see LER 50-323/2008-001, ADAMS Accession No. ML082970221, for more information).

• North Anna, Unit 2-0n October 29, 2008, while attempting to place the unit on line, the

turbine tripped on a generator lockout relay actuation. The C main transformer was

discovered to be spraying oil.

• Oyster Creek-On November 28,2008, an electrical fault internal to the M1A main

transformer led to an automatic reactor scram due to load reject. The transformer was

replaced with the spare, and on February 1, 2009, this transformer failed due to a

bushing failure, resulting in a reactor scram, fire, and declaration of a Notification of

Unusual Event (see LER 50-219/2008-001, ADAMS Accession No. ML090260082, and

LER 50-219/2009-001, ADAMS Accession No. ML090970735 for more information).

A review of licensees' root cause evaluations for the large transformer failures shows that the

events are often the result of ineffective implementation of the transformer maintenance

program.

DISCUSSION

The events described above illustrate instances in which the loss or tripping of large

transformers resulted in plant transients, reactor trips, unnecessary starting of the emergency

diesel generators (EDGs), and declaration of plant events. Transformer failures have resulted

in eight declared plant events from January, 2007, to February, 2009, making them the second

leading reason for such declarations. While the large transformers discussed in this IN are

generally non-safety related, they are within the scope of the Maintenance Rule (Title 10 of the

Code of Federal Regulations, Section 50.65, "Requirements for Monitoring the Effectiveness of

Maintenance at Nuclear Power Plants").

A relatively high incidence of transformer failures has occurred in the last few years, the majority

of which could have been avoided had the licensee fully evaluated and effectively implemented

corrective actions and recommendations identified in industry operating experience. These

corrective actions included a more effective maintenance program and a more proactive

approach to addressing abnormal indications. In particular, some utilities have installed online

automated oil analysis and monitoring system to support decisions regarding preventive and

corrective maintenance to improve transformer reliability. The Institute of Electrical and

Electronics Engineers (IEEE) provides industry guidance on this matter in Standard

C57.140-2006, "IEEE Guide for the Evaluation and Reconditioning of Liquid Immersed Power

Transformers." However, it should be noted that the NRC has not endorsed this document, and

the recommendations it contains do not constitute NRC requirements.

OAG 10000526_000002

CONTACT

This IN requires no specific action or written response. Please direct any questions about this

matter to the technical contacts listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.

IRAI IRAI

Timothy J. McGinty, Director Daniel H. Dorman, Director

Division of Policy and Rulemaking Division of Fuel Cycle Safety

Office of Nuclear Reactor Regulation and Safeguards

Office of Nuclear Materials Safety

and Safeguards

Technical Contacts: Rebecca Sigmon, NRR/DIRS Prem Sahay, NRR/DE

(301) 415-4018 (301) 415-8439 E-mail: Rebecca.Sigmon@nrc.gov E-mail: Prem.Sahay@nrc.gov

NRC generic communications may be found on the NRC public Web site, httQ:llwww.nrc.gov.

To access this information, select "Electronic Reading Room" and then "Document Collections."

OAG 10000526_000003

CONTACT

This IN requires no specific action or written response. Please direct any questions about this

matter to the technical contacts listed below or the appropriate Office of Nuclear Reactor

Regulation (NRR) project manager.

IRAI IRAI

Timothy J. McGinty, Director Daniel H. Dorman, Director

Division of Policy and Rulemaking Division of Fuel Cycle Safety

Office of Nuclear Reactor Regulation and Safeguards

Office of Nuclear Materials Safety

and Safeguards

Technical Contacts: Rebecca Sigmon, NRR/DIRS Prem Sahay, NRR/DE

(301) 415-4018 (301) 415-8439 E-mail: .R.~.Q§~~§!:.$..i.9f.D.Q!J@!J[~:.9.Qy' E-mail: p..r.§f.D.,$.§!.O.9Y.@.oJ.g:.9Q'y'

NRC generic communications may be found on the NRC public Web site, httr;:rllwww.nrc.gov.

To access this information, select "Electronic Reading Room" and then "Document Collections."

Distribution: IN Reading File

Hard Copy to Elizabeth Doolittle (Mail Stop EBB 6003 1-0 2-M)

ADAMS Accession Number* ML090540218 TAC NO ME0392 OFFICE 10EBIDIRS ACIDIRS/IOEB D/NRRIDIRS TECH EDITOR NRRIDE/EEEB BC/EEEBIDE

NAME RSigmon JThorp FBrown KAzariah-Kribbs PSahay GWilson

DATE 05/08/09 05/13/09 06/02/09 04/03/09 email 05/12/09 05/12/09 OFFICE A/NRRIDE DPR/PGCB DPR/PGCB BCIDPR/PGCB D/NRRIDPR D:FCSS

NAME ABoland DBeaulieu CHawes MMurphy TMcGinty DOorman

DATE 05/18/09 06/03/09 06/03/09 07/01/09 07/07/09 06/19/09 OFFICIAL RECORD COPY

OAG 10000526_000004