B15290, Requests Withdrawal for Use of Alternative to ASME Boiler & Pressure Vessel Code Section III for Millstone Unit 3

Requests Withdrawal for Use of Alternative to ASME Boiler & Pressure Vessel Code Section III for Millstone Unit 3

ML20086Q391
Person / Time
Site:	Millstone
Issue date:	07/25/1995
From:	Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
B15290, NUDOCS 9507280028
Download: ML20086Q391 (3)

Text

_ _ - - - _ _ - _ _ - - - _ _ _ - _ _ _ _ _ _ _ _ . - _ _ . _ -- - - - - - - - - - - - - - - - - - . . - - - - - - - - - - . - - - - - - - - - - - - - - - - - - - - .- --

d Northeast 2 *" s=w suum er 06037

//.a Utilities System  %,i uuuue. suvia cow ny P.O. Box 270 liartford, Cr 06141-0270 a

(203) 665 5000 July 25, 1995 Docket No. 50-423 B15290 Re: 10CFR50. 55a (a) (3) l U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Millstone Nuclear Power Station, Unit No. 3 Withdrawal of the Request to Use Alternative to ASME Code Section III Introduction The purpose of this letter is for Northeast Nuclear Energy Company (NNECO) to withdraw the request for the use of an alternative to the ASME Boiler and Pressure Vessel Code Section III for Millstone Unit No. 3. Specifically, NNECO, pursuant to 10CFR50. 55a (a) (3) dated June 9, 1995,m requested NRC approval to use' a different method to satisfy the requirement of the ASME Code Section III, Subsection NC 3652.3 for consideration of thermal stresses for low temperature piping systems (e.g., service water system and reactor plant component cooling water (RPCCW) system). This approval was requested for the current operational cycle only.

Backaround The proposed alternative would have permitted a small temperature excursion beyond the present RPCCW and service water system pipe stress analysis temperature during safety grade cold shutdown with elevated ultimate heat sink temperatures.

Specifically, NNECO's June 9, 1995, request was based on our intention to perform a safety grade cold shutdown operability I

(1) J. F. Opeka letter to the U.S. Nuclear Regulatory Commission,

" Request to Use Alternative to ASME Code Section III and Withdrawal of Proposed Revision to Technical Specification -

Domineralized Water Storage Tank," dated June 9, 1995.

9507280028 950725 ,

L PDR ADOCK 05000423 1 0 l P PDR

! I

U.S. Nu'c lear Regulatory Commission B151290/Page 2 July 25, 1995 determination based on RPCCW and service water (SW) piping system l maximum operating temperatures 10*F above those currently utilized in the stress analysis. Based on initial screening, a small percentage of structural components did not appear to readily meet ASME Code allowables.

As an alternative to performing detailed thermal analysis to demonstrate compliance with ASME Code Section III, Subsection NC 3652.3, in a letter dated June 9, 1995, NNECO proposed an alternative pursuant to 10CFR50.55a(a) (3) .

Discussion As discussed above, NNECO's June 9, 1995, request was based on our intention to perform a safety grade cold shutdown operability determination based on RPCCW and SW piping system maximum operating temperatures 10*F above that currently utilized in the stress analysis. However, we have since been successful in preparing an operability determination based on the original RPCCW and SW piping system maximum operating temperatures, a 75'F ultimate heat sink temperature, and Cycle 6 specific spent fuel pool cooling system heat loads.

At this time, the original RPCCW and SW piping stress analysis is applicable. Therefore, no alternative (or change in) analytical methods is needed to demonstrate ASME Code compliance. Therefore, we hereby withdraw our June 9, 1995, request.

Although not used in the current operability determination, the stress engineering assessment of the small percentage of structural components identified as not readily meeting ASME Code allowables based on the initial screening have been verified to meet ASME Code allowables based on further analysis for the postulated 10*F higher temperature.  ;

summary In summary, an engineering evaluation has concluded that no increase in RPCCW or SW piping system maximum operating temperature is required to achieve safety grade cold shutdown. This evaluation is based on a 75'F ultimate heat sink temperature (design basis maximum temperature) and a Cycle 6 spent fuel pool cooling heat load. Therefore, we hereby withdraw our June 9, 1995, request for NRC review and approval of a proposed alternate analytical method to demonstrate RPCCW and SW piping system ASME Code compliance.

i l

l 1

^

• U.S. Nuclear Regulatory Commission B15290/Page 3 July 25, 1995 ,

i If the.NRC Staff should have any questions or comments regarding ,

this submittal, please contact Mr. R. G. Joshi at (203) 440-2080.  ;

Very truly yours, f i

NORTHEAST NUCLEAR ENERGY COMPANY J.

AFGA F. OpgXa u i

Executive Vice President cc: T. T. Martin, Region I Administrator V. L. Rooney, NRC Project Manager, Millstone Unit No. 3 P. D. Swetland, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3 i

l t

i t

I 1

I

-1