ML20214X066

Safety Evaluation Re Projected Values of Matl Properties for Fracture Toughness Requirements for Protection Against PTS Events.Reevaluation of Listed Values Requested

ML20214X066
Person / Time
Site:	Arkansas Nuclear
Issue date:	12/02/1986
From:	NRC
To:
Shared Package
ML20214X057	List: ML20214X056 ML20214X066
References
REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR NUDOCS 8612100525
Download: ML20214X066 (3)

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'*9*****gt- SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING PROJECTED VALUES OF MATERIAL PROPERTIES FOR FRACTURE TOUGHNESS REQUIRENENTS FOR PROTECTION AGAINST PRESSURIZED THERMAL SHOCK EVENTS ARKANSAS POWER AND LIGHT COMPANY ARKANSAS NUCLEAR ONE, UNIT 1 DOCKET N0. 50-313 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 reactor "shall submit projected values of RT (at the inner vessel surface) of reactor vessel beltline materials by 9Nefng values from 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 22, 1986, Arkansas Power and Light Company (the licensee or AP&L) submitted projected values of RT together with material properties and fast neutron fluence of reactor vesEN beltline material for Arkansas Nuclear One, Unit 1 (ANO-1). The RT and fluence values were projected to the present end of license (E0L)PQ well as for 32 effective full power years (EFPY).

EVALUATION OF MATERIALS ASPECTS The controlling beltline material from the standpoint of PTS susceptibility was identified to be the middle circumferential weld, WF-112 (weld wire heat No. 406L44). The material properties of the controlling material and the associated margin and chemistry factor were reported to be:

8612100525 861202 PDR ADOCK 05000313 Utility Submittal Staff Evaluation P PDR Cu (copper content, %) 0.31 0.31 Ni (nickel content, %) 0.59 0.59 0 0 I (Initial RT NDT, F) 59 M (Margin, F) 59 CF (Chemistry Factor, F)

• 199.7

• Not submitted o

.e The controlling material has been properly identified, The ,iustifications given for the copper and nickel contents and the initial PT N are acceptable.

The margin has been derived from consideration of the bases Nr these values, following the PTS Rule, Section 50.61 of 10 CFR Part 50. Fauation 1 of the PTS rule governs, and the chemistry factor is as shown above.

EVALUATION OF THE FLUENCE ASPECTS Flux and fluence calculations were performed by using the discrete ordinates code D0T and plant specific sources based on previous cycles. Last cycle sources were used to extrapolate to future cycles. The critical material was identified to be the middle circumferential weld WF-112. Accordingly, the peak azimuthal and longitudinal flux was used in the calculation of the RT . The DOT transport calculations have been compared to the latest subillancecapsuleresultsandareconsistentwiththemeasurement. The method of the fluence calculation is conservative and acceptable.

EVALUATION OF THE CALCULATED ETn73 The equation specified in 10 CFR 50.61, as applicable for the ANO-1 pressure vessel is:

0 .

RT PTS = I+M+(-10+470xCu+350xCuxNi)xf .27 where: I = Initial RT =0F M =Uncertaintfkargin = 59 F Cu = w/o Copper in weld WF-112 = 0.31 Ni = w/o Nickel in weld WF-112 = 0.59 n weld WF-112 in units f =PeakQuence2 of 10 n/cm to the end of the current license and 32 effective full power years respectively = 0.86, 1.10 Then, to the present E0L:

0 RT PTS

= 59+(-10+470x0.31+350x0.31x0.59) x 0.86 27

= 59+199.7x0.96 = 250.7 F l

l Also, for 32 EFPY:

l, 0

l RT PTS = 59+(-10+470x0.31+350x0.31x0.59) x 1.10 27

= 59+199.7x1.026 = 263.9 F Both nf the above results are less than 300 F, the applicable screening criterion, and are acceptable.

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4 CONCLUSIONS The licensee has calculated values for RT P of 250.7*F at the present EOL and 263.9*F for 32 EFPY for the limiting weld J$terial. .These are both less than 300*F which is the screening criterion for the limiting weld material. This is acceptable. However, in order for the staff to confirm the licensee's throughout the life of the ANO-1 license, we request projected estimated RT thatthelicenseesubmSIba reevaluation of the RT and a comparison to the predictedvaluealongwithfuturePressure, Temper $Ibreoperatinglimitswhich are required by 10 CFR 50, Appendix G.

Date: December 2,1986 Principal Contributers: P.N. Randall L. Lois J. Ramsey G. Vissing G

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