ML20155C371

Forwards SE Re Request Relating to Pressurizer Pressures/ Shutdown Cooling Sys Interlocks.Nrc Concluded That NNECO Should Perform New SE Under Provisions of 10CFR50.59 to Determine If USQ Exits

ML20155C371
Person / Time
Site:	Millstone
Issue date:	10/30/1998
From:	Mcdonald D NRC (Affiliation Not Assigned)
To:	Bowling M, Loftus P NORTHEAST NUCLEAR ENERGY CO.
Shared Package
ML20155C376	List: ML20155C371 ML20155C378
References
TAC-MA1649, NUDOCS 9811020215
Download: ML20155C371 (3)

Text

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j UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20066 0001 ,,

g*o*****#g October 30, 1998 Mr. Martin L. Bowling, Jr.

Recovery Officer - Technical Services Northeast Nuclear Energy Company clo Ms. Patricia A. Loftus Director- Regulatory Affairs P. O. Box 128 Waterford, Connecticut 06385

SUBJECT:

LICENSE AMENDMENT REQUEST RELATING TO THE PRESSURIZER PRESSURE / SHUTDOWN COOLING SYSTEM INTERLOCKS - MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2 (TAC NO. MA1649)

Dear Mr. Bowling:

By letter dated April 29,1998, Northeast Nuclear Energy Company (NNECO) proposed to change the Final Safety Analysis Report (FSAR) for the Millstone Nuclear Power Station, Unit No. 2 (MNPS2) through an amendment to Facility Operating License No. DPR-65. This request results from its determination that the existing low-range pressurizer pressure transmitters in the shutdown cooling (SDC) system interlocks are susceptible to high inaccuracies during conditions ,

of harsh environment following a loss-of coolant accident or a main steamline break inside I containment. The replacement of these transmitters will result in the elimination of transmitter diversity as described in the MNPS2 FSAR. NNECO has determined that this deviation involves an unreviewed safety question (USQ), as defined in Title 10 of the Code of Federal Reaulations (10 CFR) 50.59.

The NRC staff has reviewed the submittal and finds that NNECO has not considered the diversity provided by the switch in the control room that removes power to one of the motor operated valves in the SDC system flow path in its evaluation of the high/ low pressure interface design.

/

The NRC staff has concluded, as detailed in the enclosed Safety Evaluation, that NNECO should /

perform a new safety evaluation under the provisions of 10 CFR 50.59 to determine if a USQ exists when taking into account the diversity provided by removing power to one of the motor- /

operated valves in the SDC system flow path. Depending on its findings, NNECO may be able to withdraw its current application for an amendment to the MNPS2 Facility Operating License No. '[

DPR 65 and proceed to the change the MNPS2 licensing basis and associated FSAR revision under the provisions of 10 CFR 50.59. If NNECO determines that a USQ still exists, it may supplement the current application by providing the results of new safety evaluation to support its request for a license amendment.

U[ $3 9811020215 981030 PDR ADOCK 05000336 P PDR h

4 M. L. Bowling, Jr. - The subject TAC number will remain open until NNECO requests the withdrawal of its amendment request or provides additional information, as the result of its new safety evaluation, to support the requested amendment. Please respond by December 11,1998, which was agreed to by Ravi Joshi of your staff. Should a situation occur that would prevent you from meeting this due date or have any questions, please contact me at 301-415-1408.

Sincerely, 0

-N Daniel G. Mcdonald, Jr., Senior Project Manager Millstone Project Directorate Division of Reactor Projects - t/11 Office of Nuclear Reactor Regulation Docket No. 50-336

Enclosure:

Safety Evaluation cc w/ encl: See next page

October 30, 1998 M. L. Bowling, Jr. The subject TAC number will remain open until NNECO requests the withdrawal of its amendment request or provides additional information, as the result of its new safety evaluation, to support the requested amendment. Please respond by December 11,1998, which was agreed to by Ravi Joshi of your staff. Should a situation occur that would prevent you from meeting this due date or have any questions, please contact me at 301-415-1408.

Sincerely, Original signed by:

Daniel G. Mcdonald, Jr., Senior Project Manager Millstone Project Directorate Division of Reactor Projects -l/Il Office of Nuclear Peactor Regulation Docket No. 50-336

Enclosure:

Safety Evaluation cc w/ encl: See next page DISTRIBUTION:

/IQochet Filey PUBLIC MSPD Reading JZwolinski WDean LBerry DMcDonald THarris (e-mail only, TLH3)

KMortenson, HICB JWermiel, HICB WBeckner, TSB OGC ACRS JDurr, RI DScrenci, RI DOCUMENT NAME: G:\ Mcdonald \MA1649.SE Tm receive a cop'r of this document, Indcate in the box: *C" = Copt w' attachrrfbrji/ enclosure *E* = Copy with attachrnent/ enclosure *N' = No copy OFFICE MSPD:PM_ M MSPD:LA \M d) @@lMl_M l l NAME MCDonafd4/t /m / L6enyt

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