ML20065L178

Forwards Request for Relief from ASME Code Section XI Requirements Re Isi,Second Interval,Unit 2

ML20065L178
Person / Time
Site:	Mcguire
Issue date:	04/14/1994
From:	Mcmeekin T DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9404200326
Download: ML20065L178 (5)

Text

-

,. 11 l DukeIbun Osmpany T.C Atattum AlcGuire Nutlear Generation 1%crtment \ke hrsident 12700Hayn Ferry Road (htG01\P) (701)37%f800

. Huntenvolle, NC2S078KA5 (icH)8iM809 Fax DUKEPOWER April 14, 1994 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555

Subject:

McGuire Nuclear Station, Unit 2 Docket Nos. 50-370 Inservice Inspection,Section XI Second Interval, Unit 2 Relief Request 94-03 Dear Sir; Pursuant to 10 CFR 50.55a(g)(5)(iii), I am submitting the attached relief request for NRC review and approval. This request for relief from ASME Code requirements involves the Unit 2 safety-related snubber selection plan required by Section XI during the second interval. A copy of-the Inservice Inspection plan that will be used during the second interval for McGuire Nuclear Station, Unit 2 was provided by my letter dated September 16, 1993.

For your information, a similar relief request was approved by the NRC for both units during the first interval. This approval is documented within a March 26, 1985 NRC letter.

Further, a similar relief request was recently approved by the NRC for Unit 1 during the second interval. This approval is documented within an October 29, 1993 NRC letter.

Should there be any questions regarding this matter, please contact Robert Sharp 0 at (704) 875-4447.

Very truly yours, c/ J Ted C. McMeekin 9404200326 940414 h PDR ADOCK 05000370 Q PDR t'

I i

N

^'

d 4

U. S. Nuclear Regulatory Commission April 14, 1994 page 2 xc: Mr. S. D. Ebneter Regional Administrator, Region II U. S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. George F. Maxwell Senior NRC Resident Inspector, McGuire McGuire Nuclear Station Mr. Victor Nerses, Project Manager Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission One White Flint North, Mail Stop 9H3 Washington, D.C. 20555 Harry Payne, Commissioner of Labor Attention: Director, Boiler & Pressure Vessel Division Department of Labor State of North Carolina 4 West Edenton Street Raleigh, North Carolina 27601 l

l l

l

. m . . __ _ ._ . ._ _. _ _._.- __ - . _ _ . _ _ _ _

1 4

t.

ATTACHMENT DUKE POWER COMPANY MCGUIRE NUCLEAR STATION Request for Relief From ASME Code Section XI Requirements I. Component for Which Relief is Requested A. Name and Identification Number All . safety-related snubbers for Unit 2 B. Function Snubbers are designed to prevent pipe motion under dynamic loads.

1 C. ASME Section XI Code Class  ;

Provides support for Class 1, 2'and 3 systems D. Valve Category Not Applicable l

II. ASME Code Section XI Requirement That Has Been Determined To

..Be Impractical ASME Boiler and Pressure Vessel Code Section XI, 1989' Edition, Article IWF-5000

-l 1

III'. Basis for Requesting Relief The McGuire Nuclear Station Technical Specification (TS)

Surveillance Requirement 4.7.8 states that each snubber required by Technical Specification (TS) 3.7.8 be operable by performing an augmented inservice inspection program (as specified by TS 4.7.8a-1). Part of this augmented inspection program (TS 4.7.8e), requires that during the first refueling shutdown and at least once per refueling thereafter, a representative sample of snubbers be tested using one of three stated sample plans.

In addition to the above TS requirement, TS 4.0.5 requires that the rules 7f ASME Boiler and Pressure vessel Code Section XI be followed. Whereas TS 4.7.8e permits for the selection of one of the three sampling plans for snubber functional tests, the ASME Code Section XI has only one sampling plan to follow.

Prior to 1980, the ASME Code Section XI and Generic Standard TS sampling plan requirements were identical. That is, the Generic Standards TS specified only one plan and it was identical to what was specified by section XI. In the 1980 i revision of the Generic Standard TS, up to date operating i experience and design practices were used as a basis for the l three sampling plans, one of which is identical to the Section XI plan. By a letter dated February 14, 1984, Duke notified the NRC that sample plan number 2 for the functional testing of snubbers would be performed during the first McGuire Unit I refueling shutdown. This plan involves functionally testing a representative sample of snubbers in accordance with TS Figure 4.7.1. Since this plan for snubber selection differs from that specified in Section XI  !

of the 1986 Edition of the ASME Code, relief from the requirements of this portion of the ASME Code is requested. q The code requirement to perform functional testing on 10%

of the total number of snubbers, with subsequent samples of an additional 10% if any snubber fails the test, is impractical for stations with large number of snubbers. The consequences of using the 10% sample plan would lead to excessive radiation exposures, an increase in reinstallation errors, additional manpower requirements, and-possibly extended outages due to the probability of being required to

. test 100% of the snubber population. Alternate sampling plans, as outlined in the McGuire TS, will provide a 95%

confidence' level that 90% of the snubbers are operable. The NRC has reviewed these alternate plans and has found them acceptable. Due to the problems of_ dealing with such a large population of snubbers as required under the 10% plan, we would anticipate an actual decrease in the level of safety provided. McGuire Units 1 and 2 have a total population of approximately 2500 safety related snubbers.

, IV .' Alternate Testing Safety-related snubbers will be functionally tested per plan number 2 of the alternative plans in the McGuire TS 3/4.7.8.e.

V. Implementation Schedule McGuire safety-related snubbers will continue to be functionally tested per the requirements of the TS.

. . _