ML17352A687

Discusses Review of Residual RHR Flaw Indications in Check Valve 3-753

ML17352A687
Person / Time
Site:	Turkey Point
Issue date:	06/17/1994
From:	Croteau R Office of Nuclear Reactor Regulation
To:	Goldberg J FLORIDA POWER & LIGHT CO.
References
NUDOCS 9406290314
Download: ML17352A687 (6)

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Wp**W Docket No. 50-250 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 17, 1994 Hr. J.

H. Goldberg President - Nuclear Division Florida Power and Light Company P. 0.

Box 14000 Juno

Beach, Florida 33408-0420

SUBJECT:

TURKEY POINT NUCLEAR POWER STATION, UNIT 3 REVIEW OF RESIDUAL HEAT REMOVAL (RHR)

FLAW INDICATIONS - TAC NO. H84743 As part of our review of your 10 CFR 50.59 Safety Evaluations, we performed a

detailed appraisal of your assessment of the crack in RHR Check Valve 3-753.

We conclude that the check valve can safely operate and you should continue to inspect the flaw at 60-month intervals.

In your interoffice correspondence dated Harch 3, 1992, you summarized your evaluation of the RHR system swing check valve 3-753A, which has a flaw indication at the disk seating surface.

By letter dated September 14,

1993, you provided additional information justifying re-inspection at 60-month intervals.

We have reviewed your inspection schedule and found the first 60-month inspection in 1996 is consistent with IWB-2420.

The next two 60-month intervals will occur beyond the recommended intervals of IWB-2420.

However, since the projected crack growth is small (0.473 inches after 40 years),

the critical flaw size is large, and the component is an ASNE Code Class 2 valve, inspecting the flaw at 60-month intervals is acceptable.

If any inspections 94062903i4 9406i7 PDR ADOCK'50Q0250

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Your stress analysis over-simplified the structural geometry of the check valve and the response of fluid temperature changes on parts of the structure while neglecting the effect of check valve slam.

We recognize the complexity of the structure analyzed and believe the only comprehensive means of computing the stresses in the check valve would have been by application of finite element techniques.

This would have determined the relative responses of different parts of the structure under pressure and thermal loading and the resulting interaction stresses at the crack front developed as a result of these loadings during the operating transients.

We acknowledge that the material properties and critical stress intensity=factors are conservative and may be used in critical flaw size and crack growth rate determination.

We find that the critical flaw size is large in comparison with check valve dimensions and the growth of the flaw over the remaining lifetime will be small.

Therefore, regardless of your over-simplification and neglect of check valve slam, we believe the check valve will be operable with the flaw.

indicate that the crack growth analysis is non-conservative, you should provide a revised analysis which addresses all uncertainties, prior to placing the valve in-service.

With respect to root cause of the crack, incomplete information exists and consider ation of the root cause of the initial flaw may be of significance to the evaluation.

For example, the welding process used in attaching the Stellite No.

6 strip to the check valve body may have changed the cast austenitic stainless steel material properties unfavorably and created an initial flaw.

This possibility had not been discussed by APTECH in their reports.

The root cause of the indicated flaw should be investigated and an assessment made of generic implications of the findings on other check valves of similar design and application.

In summary, we request that you (1) confirm your intent to inspect and assess the crack in 60-month intervals, reporting any non-conservative results to us; (2) determine the root cause of the initial flaw, if not already determined, and inform us of your conclusion; and (3) inform us of your assessment of the generic implications and inspection findings on other valves of similar design and application.

We request that you provide a schedule and plan within 60 days to address these requests.

This request affects fewer than 10 respondents and, therefore, is not subject to Office of Management and Budget review under P.L.96-511.

If you need any additional information or have any questions, please call me at (301) 504-1481.

Sincerely, (Original Signed By) cc:

See next page Distribution See next a

e Richard P. Croteau, Project Manager Project Directorate II-2 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation PM: PDI I-2 CB LA:PDI I-2 OFFICE ETana E<<

rosnider RCrotea NAME 06/ 5 94 06 d 94 06 94 DATE OFFICIAL RECORD COPY DOCUMENT NAME: G:i84743.RHR D:PD HBerk 06 I

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Mr. J.

H. Goldberg Florida Power and Light Company Turkey Point Plant CC:

Harold F. Reis, Esquire Newman and Holtzinger, P.C.

1615 L Street, N.W.

Washington, DC 20036 Jack Shreve, Public Counsel Office of the Public Counsel c/o The Florida Legislature ill West Madison Avenue, Room 812 Tallahassee, Florida 32399-1400 John T. Butler, Esquire

Steel, Hector and Davis 4000 Southeast Financial Center Miami, Florida 33131-2398 Mr. Thomas'F.

Plunkett, Site Vice President Turkey Point Nuclear Plant Florida Power and Light Company P.O.

Box 029100 Miami, Florida 33102 Joaquin Avino County Manager of Metropolitan Dade County ill NW 1st Street, 29th Floor Miami, Florida 33128 Senior Resident Inspector Turkey Point Nuclear Generating Station U.S. Nuclear Regulatory Commission P.O.

Box 1448 Homestead, Florida 33090 Mr. Bill Passetti Office of Radiation Control Department of Health and Rehabilitative Services 1317 Winewood Blvd.

Tallahassee, Florida 32399-0700 Mr. Joe Myers, Director Division of Emergency Preparedness Department of Community Affairs 2740 Centerview Drive Tallahassee, Florida 32399-2100 Regional Administrator,'egion II U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W. Suite 2900 Atlanta, Georgia 30323 Attorney General Department of Legal Affairs The Capitol Tallahassee, Florida 32304 Plant Manager Turkey Point Nuclear Plant Florida Power and Light Company P.O.

Box 029100 Miami, Florida 33102 Mr. H. N. Paduano, Manager Licensing 5 Special Projects Florida Power and Light Company P.O.

Box 14000 Juno

Beach, Florida 33408-0420 Mr. Edward J.

Weinkam Licensing Manager Turkey -Point Nuclear Plant P.O.

Box 4332 Princeton, Florida 33032-4332

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Memorandum Dated

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& Local PDRs PDII-2 RF S.

Varga G. Lainas H. Berkow R. Croteau J. Strosnider E. Tana OGC ACRS (10)

D. Verrelli, RII B. Elliot

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