ML20212N023

Safety Evaluation Supporting Util 860123 & 0507 Submittals Re Projected Values of Matl Properties for Fracture Toughness Requirements for Protection Against Pts,In Compliance w/10CFR50.61

ML20212N023
Person / Time
Site:	Fort Calhoun
Issue date:	03/05/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20212N019	List: ML20212N018 ML20212N023
References
NUDOCS 8703120317
Download: ML20212N023 (4)

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UNITED STATES o NUCLEAR REGULATORY COMMISSION

{ ,i WASHINGTON. D. C. 20666

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION, UNIT NO. 1 DOCKET NO. 50-285 PROJECTED VALUES OF MATERIAL PROPERTIES

-FOR FRACTURE TOUGHNESS-REQUIREMENTS FOR PROTECTION AGAINST PRESSURIZED THERMAL SHOCK EVENTS 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 submitbeltline projected materials valuesby ofgRT@ng(at values thefrominner the vessel time of submittal to.the expiration date of the operating license.- The assessment must specify the bases for the projection i_ncluding 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, as supplemented by letter dated May 7, 1986, the Omaha Public Power District, the licensee for Fort Calhoun Station, Unit No.1, submitted information on the material properties and fast neutron fluence (E > 1.0 Mev) of the reactor pressure vessel in compliance with 10 CFR 50.61.

EVALUATION OF THE MATERIALS ASPECTS The controlling beltline material from the standpoint of PTS susceptibility was identified to_be lower shell longitudinal weld seam 3-410.

The material properties of the controlling material and the associated margin and chemistry factor were reported to be: '

Utility Submittal Staff Evaluation >

Cu (copper content, %) = 0.23 0.23 ,

Ni (nickel content, %) = 0.95 0.95 I (Initial RT F) = - 56 - 56 M-(Margin,'F$OT, = 59 59 CF (Chemistry Factor, *F)= 175 174.6 ,

The controlling material has been properly identified. The justification given for the copper and nickel contents and the initial RT N are acceptable. The margin has been derived from consideration N the bases for'these values, following the PTS Rule, Section 50.61 of 10 CFR Part 50.

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

8703120317 870305 PDR ADOCK 05000285 p PDR

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EVALUATION OF THE FLUENCE AND RTo ASPECTS

- The methodology for the fluence calculations was based on the discrete ordinates code DOT 4.3 and the results from the analysis of surveillance capsule W-265. However, the results of the fluence calculation were' independently verified by the staff's contractor, Brookhaven National Laboratory (BNL), which performed the calculations with a P3 scattering approximation, an Sa quadrature, and ENDF/B-IV based cross sections. The neutron sources for the projection to 32 effective full power years were based on the average source distribution from Cycle 8. This is conservative because Cycles 9 and 10 loading achieved lower neutron leakages. Future cycles will be similar to Cycles 9 and 10 or will achieve even lower leakage.

Comparison of the licensee fluence results and the corresponding values obtained by BNL indicate that the licensee proposed RT values are conservative and, therefore', acceptable. ThefollowinhTkableliststhe complete set of the results obtained by BNL, including RT calculated using Equation 1specifiedin10CFR50.61,comparedtothosephosedbythelicensee.

BNL C-E 84 C-E 86 VESSEL EFPY FLUENCE . RT FLUENCE RT FLUENCE RT 101s n/cm2 opts 1018 n/cm2 opts 1018 n/cm2 opts 8.93 9.84 176.8 11.39 183.8 11.96 186.2 25.0 18.96 210.5 22.58 220.6 28.83 235.4 32.0 22.93 221.4 27.64 232.4 36.18 248.3 L

40.0 27.47 232.4 33.03 244.1 44.58 264.4 7

l C-E 86 From the licensee submittal January. '86 Reference 1 C-E 84 From an earlier submittal, for comparison l

As previously discussed, the longitudinal weld seam 3-410 has been identified as the limiting beltline material (Reference 3). The above table shows the BNL value, for 32 effective full power years, to be 221.4 F and the licensee value is 248.3 F. Both are lower than 270*F, the applicable 10 CFR 50.61 screening criterion, and are acceptable.

l l CONCLUSIONS of 248.3*F of the limiting material for 32 ThelicenseehascalculatedaRT[$ tion.The staff's contractor calculated effective full power years of oph 221.4*F. The Fort Calhoun reactor is projected to have less than 32 effective full power years of operation at the expi. ration of the license (June 7, 2008).

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4 Both the RT values calculated by the staff's contractor and by the licensee o - arelessthWRT270ar which is the screening criterion for the limiting material at the expiration date of.the license. This is acceptable and thus meets the requirements of the PTS Rule.

In order for us to confirm the licensee's projected estimated RT throughout thelifeofthelicense,wewillrequestthelicenseetosubmit$The-evaluation of the RT and comparison to the predicted value with future Pressure-TemperatuhIbsubmittals which are required by 10 CFR Part 50, Appendix G.

Date: March 5,1987 Principal Contributors:

P. Randall and L. Lois l

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. References

1. Letter from R. L. Andrews,' Omaha Public Power District, to A. Thadani, NRR, dated January 23, 1986.

2. Letter from R.-L. Andrews, Omaha Public Power District, to A. Thadani, NRR, dated May 7, 1986.

3. BNL Memorandum for J. Carew from D. Cokinos, " Review of the Ft. Calhoun Pressure Vessel Fluence and RT PTS submittal" dated October 10, 1986 (Draft).

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