ML20211A231

Safety Evaluation Supporting Util 860123 & 0220 Responses to 10CFR50.61 Re Pressurized Thermal Shock Rule.Submittal of Reevaluation of Rt(Pts) & Comparison W/Predicted Value in Future pressure-temp Submittals Required

ML20211A231
Person / Time
Site:	Waterford
Issue date:	05/29/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20211A175	List: ML20211A172 ML20211A231
References
REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR NUDOCS 8606110089
Download: ML20211A231 (3)

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( o UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20655 h

'+, SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING PROJECTED VALUES OF MATERIAL PROPERTIES FOR FRACTURE TOUGHNESS REQUIREMENTS FOR PROTECTION AGAINST PRESSURIZED THERMAL SHOCK EVENTS LOUISIANA POWER AND LIGHT COMPANY WATERFORD STEAM ELECTRIC STATION, UNIT 3 DOCKET NO. 50-382 .

INTRODUCTION As required by 10 CFR 50.61, " Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock" (PTS Rule) which was published in the Federal Register July 23, 1985, the licensee for each operating pressurized water surface) reactor "shallvessel of reactor submit projected beltline values materials byof g RT@ng(at values the frominner vessel the time of submittal to the expiration date of the operating license. The assessment must specify the bases for the projection including the assumptions regarding core loading patterns. This assessment must be submitted by January 23, 1986, and must be updated whenever changes in core loadings, surveillance measurements or other information indicate a significant change in projected values."

By letter dated January 23, 1986, revised by letter dated February 20, 1986, a Louisiana Power and Light Company (the licensee or LP&L) submitted projected ...-

values or RT together with material properties and fast neutron fluence of reactorvessSI3 beltline material for Waterford Steam Electric Station, Unit ,'

3. The RT and fluence values were projected to 33.6 effective full power years (EFPYI3which.is considered to be beyond the expiration date of the license.

EVALUATION OF THE MATERIALS ASPECTS .i The controlling beltline material from the studpoint of PTS susceptibility 4 was identified to be Plate M-1004-2. The material properties of the t:

controlling material and the associated margin and chemistry factor were 7 reported to be:

Utility Submittal Staff Evaluation ,

Cu (copper content, %) 0.03 0.03 Ni (nickel content, %) 0.58 0.58 I (Initial RT PTS, F) 22 22 M(Margin,'F) 48  ;?

CF (Chemistry Factor, 'F) ,

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. i The controlling material has been properly identified. The justification given for the copper and nickel contents and the initial RT are acceptable. ThemarginhasbeenderivedfromconsiderationSIthebasesfor N these values, following the PTS Rule, Section 50.61-of 10 CFR Part 50.

Equation 1 of the PTS Rule governs, and the chemistry factor is as shown above.

EVALUATION OF THE FLUENCE ASPECTS The licensee used a maximum fluence of 3.68x10 13 n/cm2 (E > 1.0 MeV) on plate '

material for calculating RT This value was determined by tests described inFSAR5.3.1.4andenvelopN3 planned core loading patterns. To gain a quantitative estimate of the available margin in terms of fluence, we solve Equation 1 of the PTS Rule for fluence.

RT PTS I+M+(-10+470xCu + 350xcuxNi)f.27 Where: I =

iratial RTNDT = 22*F M = uncartainty = 48*F Cu =  % cyper in plate M-1004-2 = .03 Ni =  % nickel in plate M-1004-2 = .58 f a peak fluence (E 2: 1.0MeV)onplate 2

M-1004-2 x 10-19 cm /n = 3.68 0

Then: 270 = 22+48+(-10+470x0.03+350x0.03x0.58)f .27 f = 61,451 (which is outside the range of available experimental data, by a very large margin)

Therefore: the margin in fluence = 61451/3.68 = 16,698 EVALUATION OF THE CALCULATED RT g The limiting beltline material is Plate M-1004-2 and Equatioa 1 of the PTS Rule governs. Equation 1 specified in 10 CFR 50.61 applicable to the Waterford reactor vessel is:

RT PTS = I+N+(-10+470xCu + 350xCuxNi)f.27 Where: I, M, Cu, and Ni is as given above and f = peak fluence (E y 1.0 MeV) on plate 2

M-1004-2 x 10-19 cm /n = 3.68 Then: 0 RTPTS = 22+48+(-10+470x0.03+350x0.03x0.58)x3.68 27 RTPTS = 22+48+10.19x1.42 = 84.5 F 4 270*F

• The 84.5*F meets the 10 CFR 50.61 screening criteria of .270*F by a very large margin and is, therefore, acceptable.

CONCLUSIONS The licensee has calculated a RT of 85 F for plate material at the end of 33.6EFPYwhichisbeyondthenoSIbal32EFPYconsideredinthedevelopmentof 4 the PTS Rule. This is less than 270 F, which is the screening criteria for the l limiting material at expiration date of the license. This is acceptable.

However, in order for the staff to confirm the licensee's projected RT p throughoutthelifeoftheWaterford3operatinglicense,thelicenseeI5 required to submit a re-evaluation of the RT and comparison with the predictedvalueinanyfuturePressure-Tempe$lkuresubmittalswhichare submitted as required by 10 CFR 50, Appendix G.

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