B16732, Forwards Addl Info to Support Proposed License Amend Re Containment Penetration Conductor Overcurrent Protective Devices,Per 970829 Request

Forwards Addl Info to Support Proposed License Amend Re Containment Penetration Conductor Overcurrent Protective Devices,Per 970829 Request

ML20211C524
Person / Time
Site:	Millstone
Issue date:	09/18/1997
From:	Brothers M NORTHEAST NUCLEAR ENERGY CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20211C529	List: B16732, Forwards Addl Info to Support Proposed License Amend Re Containment Penetration Conductor Overcurrent Protective Devices,Per 970829 Request ML20211C538 ML20211C604 ML20211C610 ML20211C631
References
B16732, TAC-M98678, NUDOCS 9709260230
Download: ML20211C524 (7)

Text

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Nht ""P' F'"7 "d- (""" 2 56)' '"'"'d C' 6385 Nuclear Energy waisione Nucie., ro.er stasin Northeast Nuclear Erwrgy Company P.O. Box 128 Waterford, Cr 06385-0128 (860) 447 1791 Fan (860) 444-4277 The Nortlwast Utihties Systern SEP l 81997 Docket No 50-423 B16732 Re: 10CFR 50.90 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Millstone Nuclear Power Station Unit No. 3 Proposed Revision to Technical Specification Containment Penetration Conductor Overcurrent Protective Devices ,

(PTSCR 3-23-37) (TAC NO. M98678) 4 Pesconse to Reouest for Additional information in a letter dated May 5,1997, Northeast Nuclear Energy Company (NNECO) proposed to amend Operating License NPF-49 by revising Millstone Unit No. 3 Technical Speci'ication Surveillance 4.8.4.1 and its Bases Section. The NRC Staff, in a letter dated August 29,1997, requested NNECO to provide additional information to support our proposed license amendment.

Attached are our responses to the NRC Staffs questions. If you have any additional questions, please contact Mr. D. Smith at (860) 437-5840.

NORTHEAST NUCLEAR ENERGY COMPANY Nh M. H. Brothers' V N Vice President - Millstone Unit No. 3 cc: H. J. Miller, Region i Administrator l 1)

J. W. Andersen, NRC Project Manager, Millstone Unit No. 3 A. C. Cerne, Senior Resident inspector, Millstone Unit No. 3 W. D. Travers, PhD, Director, Special Projects Office I 9709260230 970918 PDR ADOCK 05000423 P PDR i i kif b

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Docket No. 50-423

B16732 1

Attachment 1 J

Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specification Containment Penetration Conductor Overcurrent Protective Devices (PTSCR 3-23-97)) (TAC NO. M98678)

NNECO's Commitments V

J September 1997

U.S. Nuclear Regulctory Commission -

B16732%ttachment 1\Page 1 Enclosure List of Regulatory Commitments The following table identifies those actions committed to by NNECO in this

document. Please notify the Manager - Nuclear Licensing at the Millstone Nuclear Power Station Unit No 3 of any questions regarding this document or any associated regulatory commitments.

Commitment Commitment

Date or Outage NONE NONE a

a i

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.l 4

1 4

4 t

. , l Q3cket No. 50-423 B16732

, Attachment 2 Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specification Containment Penetration Conductor Overcurrent Protective Devices (PTSCR 3-23-97) ) (TAC NO. M98678)

Response to Reauest for Additional Information September 1997

U.S. Nuclear Regulctory Commission B16732\ Attachment 2\Page 1 Millstone Nuclear Power Station, Unit No. 3 Response to Reouest for Additional Information for PTSCR 3-23-97 4

1. Long-Time and Short-Time Trip Delay Testing (a) Please submit the representative station procedure (s) responsible for the testing of the air circuit breakers, molded case circuit breakers, and i unitized starters under TS Surveillance 4.8.4.1.a.2

Response

The following procedures are provided:

SP3712T Containment Penetration Overcurrent Device Surveillance Testing for Load Center, MCC, and Molded Case Breakers SP3712T Maint. Forms 3712T-1 through -5 3P3712TA Containment Penetration MCC Starter and Molded Case Breaker PM SP3712TA Maint. Forms 3712TA-1 through -3 SP3712TB Containment Penetration 480 Volt Load Center Breaker PM and Testing SP3712TB Maint. Forms 3712TB-1 SP3712TC 6.9KV Containment Penstration Breaker PM SP3712TC Maint. Forms 3712TC-1 s

J (b) Please cite other examples where the TS Bases are utilized to contain exclusively the acceptance criteria and test parameters for surveillance requirements.

4

Response

The proposed amendment relocates test paramenters but maintains test acceptance criteria in the surveillance requirements. Clarifying information for test parameters (i.e., approximately 300 %/150 % test input current) is placed in the Bases. The test acceptance criteria remains in the text of the surveillance requiremont (i.e., +40%/-25%, +/-20% and to verify acceptable operation within the time delay bandwidth for the test current used per the Manufacturer's specifications)

U.S. Nucle r Regulatory Commission B16732\ Attachment 2\Page 2 (c) Discuss its implementation of functional tests for breaker operation vnrsus the testing of the breaker components. -

B_esconse in the event of a single pole test failure in a breaker used in ungrounded 480V circuits, two pole in series testing would be performed.11 all combinations of two poles in series testing meets acceptance criteria, the breaker is considered operable and testing of an additional 10% of the breaker population would not be required. As a good maintenance practice, the breaker would generally be changed out due to its degraded condition.

At no time would the breaker be considered inoperable solely because of a single pole failure.

2. Two Poles in Series Testing (a) Please provide the technical basis for the change in sampling methodology given the indication of a breaker failure (i.e., single pole test failure).

Response

As approved in Amendment 13 to the MP3 Technical Specifications, single pole failure follow-on series combination pole testing is only applicable to the instantaneous elements of molded case circuit beakers / unitized starters in ungrounded 480V circuits that are monitored for grounds. Operability is determined based on the results of the poles-in-series test. A series ,

combination pole test failure would invoke further testing of the breaker population as stated in current Technical Specifications. The current proposed amendment does not change the sampling methodology. This change clarifies the information provided from Amendment 13.

(b) Under the current TS surveillance wording, a breaker found inoperable with the instantaneous element on one pole out of calibration shall be restored to operable status prior to resuming operation. Please justify resuming plant operation in the case where one pole is out of calibration on the tested molded case circuit breaker.

U.S. Nuclear Regulitory Commission B16732\ Attachment 2\Page 3

Response

The current surveillance states ' Circuit breakers found inoperable during functional testing shall be restored to OPERABLE status prior to resuming operation." Determination of 480V breaker operability is not solely based on instances of single' pole test failure. This proposed amendment to the Technical Specifications does not change the testing philosophy, This proposed amendment clarifies the previously approved information from Amendment 13. The Safety Evaluation that accompanied Amendment 13 states *K all combination test results fall within the specified tolerances the circuit breaker can be declared operable".

This is implemented in our test program by the pm.Aice of requiring two pole in series combination testing if a single pole test failure occurs for 480VAC ungrounded circuits. Successful completion of the follow-on combination testing establishes breaker operability.

3, For the above questions, please address the potential for common mode failures (i.e., exceeding specified tolerances) during operation.

Response

if a two poles in series overcurrent test of a breaker fails, the breaker would be considered a test failure and inoperable. The additional 10% testing of

-breaker type population requirement would be performed and would determine if a common mode failure existed, if only a single pole is affected, the breaker is still operable and is not considered to be a failure.