ML17334B282

Provides Addl Info Re 860127 Application for Amends to Licenses DPR-58 & DPR-74 Changing Logic for Reactor Coolant Pump Breaker Position Trip Above Permissive P-8 to Two Out of Four Breakers Open.Fee Paid

ML17334B282
Person / Time
Site:	Cook
Issue date:	12/21/1988
From:	Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Murley T NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML17325B074	List: ML17325B073 ML17334B282
References
AEP:NRC:0895G, AEP:NRC:895G, NUDOCS 8812300232
Download: ML17334B282 (10)

Text

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A'CCESSION NBR:8812300232 DOC.DATE: 88/12/21 NOTARIZED: NO DOCKET FACIL:50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana & 05000315

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50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana & 05000316 AUTH. NAME AUTHOR AFFILIATXON ALEXXCH,M.P. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECXPIENT AFFXLIATION MURLEY,T.E. Document Control Branch (Document Control Desk) R

SUBJECT:

Supplemental application for amend to Licenses DPR-58 & I DPR-74 re RCP breaker position trip above P-8.Fee paid.

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Indiana Michigan Power Company P.O. Box 16631 Coiumbus, OH 43216 AEP:NRC:0895G Donald C. Cook Nuclear Plant Unit Nos. 1 and 2 Docket Nos. 50-315 and 50-316 License Nos. DPR-58 and DPR-74 RCP BREAKER POSITION TRIP ABOVE INFORMATION P-8'DDITIONAL U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Attn: T. E. Murley December 21, 1988

Dear Dr. Murley:

In AEP:NRC:0895D dated January 27, 1986, we submitted an application for amendment to our Technical Specifications (T/Ss) in which we proposed to change the logic for the reactor coolant pump breaker position (RCPBP) trip above permissive P-8 from one out of four breakers open to two out of four breakers open. Your staff subsequently requested that we provide additional information to support our proposal. Specifically we were to provide (1) a report from Westinghouse Electric Corporation (Westinghouse) stating that the proposed change would not advyr'sely affect public health and safety and (2) an explanation of/why the change would be of benefit in light of the fact that it would eliminate some protective system diversity.

In response to the first concern, we requested that Westinghouse review the proposed change. Their review and concurrence are documented in a letter from H. C. Walls (Westinghouse) to M. P.

Alexich dated May 9, 1986, which is included as Attachment 1 to this letter. The letter states that Westinghouse has not taken credit for the reactor trip on a single RCP breaker position above P-8 for any accident analysis for the Donald C. Cook Nuclear Plant Units 1 and 2 and that the change would not degrade the performance of the reactor protection system or its conformance to system functional requirements. The conclusion by Westinghouse is that the proposed change is acceptable.

In response to the second NRC concern, we believe that the change would be of benefit since it would reduce the number of spurious trips caused by failure of our Control Room Instrumentation Distribution System (GRID) and reduce challenges to our reactor p~l protection system (RPS). I I g(5P 8812300232 881221 0>~

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ATTACHMENT 1 TO AEP:NRC:0895G WESTINGHOUSE REVIEW OF THE PROPOSED TECHNICAL SPECIFICATION CHANGES REGARDING DELETION OF THE REACTOR COOLANT PUMP BREAKER POSITION TRIP ABOVE PERMISSIVE P-8

Dr. T ~ E. Murley AEP:NRC:0895G Despite the extensive hardware modifications implemented to prevent spurious trips and the resulting plant transients, we recently had a reactor trip caused by spurious initiation of the RCPBP trip. We therefore believe that our proposed T/S change is necessary to supplement the hardware modifications and request that your staff proceed with their review of our T/S change request.

It is noted that this change in RPS logic is provided as a retrofit for all Westinghouse PWR units, and all domestic PWR units'upplied subsequent to Three Mile Island incorporate this change.

The change in design from one out of four to two out of four logic will be scheduled for implementation after approval of this T/S change is received.

For your convenience, our original submittal (AEP:NRC:0895D) is included as Attachment 2 to this letter. The significant hazards analysis (SHA) included in our original submittal did not separate our analysis for each of the 10 CFR 50.92 criteria; therefore, Attachment 3 provides a more detailed SHA which addresses each of the criteria separately. Finally, changes have been made to the affected pages since our original proposal was submitted, and Attachment 4 therefore contains a revised set of T/S pages.

This submittal supplements our earlier T/S application and the

$ 150.00 application fee has therefore not been included.

This document has been prepared following Corporate procedures which incorporate a reasonable set of controls to ensure its accuracy and completeness prior to signature by the undersigned.

Sincerely, M. . Alexich Vice President ldp Attachments cc.'. H. Williams, Jr.

W. G. Smith, Jr. - Bridgman R. C. Callen G. Bruchmann G. Charnoff NRC Resident Inspector - Bridgman A. B. Davis - Region III

Hor 355 Westinghouse Water Reactor Pinsbur~p Pennsylvania i 5230 0355 Electric Corporation Divisions AEP-86-556 May 9, 1986 NS-OPLS-OPL-I-86-121 AEP P.O. 01882 Mr. M. P. Alexich, Victs President W G.O. CB-10009 and Director Nuclear Operations American Electric Power Service Corporation One Riverside Plaza Columbus, Ohio 43216 Attention: D. VanDeusen AMERICAN ELECTRIC POtKR SERVICE CORPORATION D. C. COOK UNITS 1 5 2 DELETION OF RCP BREAKER POSITION REACTOR TRIP (ABOVE P-8)

Dear Mr. Alexich:

In response to your request, this letter addresses concerns raised about the deletion of the reactor trip on a single reactor coolant pump breaker position .

above P-8 for D. C. Cook Units 1 and 2. The reactor trip from breaker position is changed from 1 out of 4 RCP breakers open above the P-8 'power level setpoint to 2 out of 4 breakers open for all power levels above the P-7 setpoint. The NRC has raised concerns about the effect of this logic change on the diversity and redundancy of the reactor protection system (RPS) for the single loop loss of flow event.

In the event of a single loop loss of flow, the low flow reactor trip is the design protection, and i.t meets the design requirement of maintaining minimum DNBR above the limit value. If no credit is taken for the low flowinreactor trip, DNBR may be less than the limit value at the limiting point the transient. However, a reactor trip on high Delta-T would terminate the accident before DNB occurs in a significant portion of the cor e. Westinghouse analysis shows that the hot spot clad temperature (on the inner clad surface) remains well below the melting point.

AEP-86-556 NS PPLS-QPL-I-86-121 Three redundant flow channels are provided for each loop for the low flow reactor trip. Above P-8, loss of flow in any loop, as sensed by two out of three channels, actuates a reactor trip. For the high Delta<<T reactor trips, one channel per loop is provided, and high Delta-T sensed by any two.channels trips the reactor.

We deletion of reactor trip on a single RCP breaker position above P-8, as described above, affects only the coincidence logic of the RPS and does not degrade either its performance or conformance to system functional requirements. In addition, it should be noted that Westinghouse has not taken credit for reactor trip on a single RCP breaker position above P-8 for any accident analyses for D. C. Cook Units 1 and 2. Also the change provides a reduction of challenges (i.e. spur ious trips) to the RPS.

Westinghouse concludes that the deletion of reactor trip on a single reactor coolant pump breaker position above P-8 is acceptable. The diversity and redundancy of the reactor protection system is maintained for the single loop loss of flow event.

If you have qny questions or ccmments regarding the preceding, please call Bill Rinkacs (412) 374-4043, Larry Tomasic (412) 374-4715, or the undersigned.

Very truly yours, H. C. Walls, Project Manager LVT:dmr Projects Department cc: M. P. Alexich J. G. Feinstein V. VanderBurg J. Markowsky S. H. Steinhart D. R. Hafer J. R. Jensen R. W. Jurgensen W. G. Smith B. Svensson M. J. Parvin, W

AEr-86-556 NS-OPLS-OPL-I-86-121 bcc: H. C. Walls/Letter File C. C. Swist 7/306 NSID Plant Data Files 7/109 M. J. Parvin - D. C. Cook J. Waleko Columbus W. T. Comerford - Chicago R. P. DiPiazza - MNC-414 OPL Letter File - MNC-411 Denise Rohaus L. V. Tomasic - MNC M.S. 4/08 W. J. Rinkacs, MNC 416 M. P. Osborne, MNC 414

ATTACHMENT 2 TO AEP:NRC:0895G TECHNICAL SPECIFICATION CHANGE APPLICATION SUBMITTED ON JANUARY 27, 1986