ML20137L706

Forwards Assessment of Pressurized Thermal Shock Ref Temps for Reactor Vessel Beltline Shell Plate & Weld Matls, Required by 10CFR50.61

ML20137L706
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	01/23/1986
From:	Withers B PORTLAND GENERAL ELECTRIC CO.
To:	Varga S Office of Nuclear Reactor Regulation
References
REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR TAC-59991, TAC-63527, NUDOCS 8601280064
Download: ML20137L706 (3)

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-E um art D V.nn Vce Presa1ert January 23, 1986 Trojan Nuclear Plant Docket 50-344 License NPF-1 Director of Nuclear Reactor Regulation Attn:

Mr. Steven A. Varga Director, PWR-A Project Directorate No. 3 U.S. Nuclear Regulatory Comission Washington DC 20555

Dear Sir:

TROJAN NUCLRAR PLANT Calculated Values of Pressurized Thermal Shock Reference Temperature (RTPTS)

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Reference:

10 CFR 50.61 Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Attached is our assessment of pressurized thermal shock reference temperatures for the Trojan reactor vessel beltline shell plate and I

wold materials required by the referenced regulation.

Inasmuch as all RTPTS values are less than the pressurized thermal shock screening criteria, this is our final response.

Sincerely,

U Bart D. Withers Vice President Nuclear Attachment c:

Mr. Lynn Frank, Director State of Oregon Department of Energy Mr. John B. Martin Regional Administrator Region V AD - J. KNIGliT (1tr only)

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e' Mr. S. A. Varga January' 23, 1986 Attachment Page 1 of 2 TROJAN NUCLEAR PLANT PRESSURIZED THERMAL SHOCK REFERENCE TEMPERATURE (RTPTS) CALCULATIONS

Reference:

1.

WCAP-10861 Analysis of Capsule X From PGE Trojan Reactor Vessel Radiation Surveillance Program, S. E. Yanichko, et al June 1985.

2.

PGE (B. D. Withers) to NRC (S. A. Varga) letter submittal of WCAP-10861, dated January 23, 1986.

3.

PGE (D. Broehl) to NRC (Schwencer) letter concerning Reactor Vessel Material Surveillance Program, dated May 22, 1978.

1.

Vessel Beltline Material of Interest:

Intermediate Shell Plates Lower Shell Plates Intermediate-to-Lower Shell Circumferential Weld Metal Intermediate Shell Longitudinal Weld Metal Lower Shell Longitudinal Weld Metal 2.

Best Estimate Neutron Fluence:

The present and projected fluence values utilized in the RTpyg calculations are based upon analysis of Surveillanco Capsule I by Westinghouse as documented in Reference 1.

Capsule I was removed from the reactor after 4.28 effective full-power years (EFPY) of plant operation in May 1984.

The surveillance capsule container was positioned axially such that the specimens were centered on the core mid-plane, spanning the central five feet of the 12-foot high reactor core. The analysis of the neutron environment within the Trojan reactor geometry, predic-tions of neutron flux magnitude and energy spectra, and core power distribution are explained in detail in Section 6 of Reference 1.

A copy of Reference I was submitted to the NRC in Reference 2.

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One further point of interest regarding these analyses is that the design bases assumes an out-in fuel loading pattern-(fresh fuel on the periphery) for 32 EFPY. PGE's future plans for low-leakage loading-patterns could significantly reduce the calculated end-of-life neutron fluence level presented below. The value of 32 EFPY is conservative considering the remaining years in the operating license and a 100 percent capacity factor.

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y Mr. S. A. Varga January 23, 1986 Attachment Page 2 of 2 In summary, the current and end-of-life fluence experienced at the inner radius of the vessel, which is the most limiting location, are:

Current EFPY fluence (E > 1.0 MeV), calculated:

3.87 x 1018 n/cm2 End-of-life fluence (E > 1.0 MeV), calculated:

2.89 x 1019 n/cm2 3.

Calculation of RTPTS:

For each material, RTPTS is the lower of the results given by Equations 1 and 2.

Equation 1:

RTPTS = I + H + (-10 & 470 Cu + 350 CuNijf.270 0

Equation 2:

RTPTS = I + M + 283f.194 0

I - Initial Reference Temperature (RTEDT)

M - Margin to be added to cover uncertainties in the values of RTNDT Copper and nickel fluence and the calculational procedures.

Cu - Weight percent of copper content.

Ni - Weight percent of nickel content.

f - Best estimate neutron fluence in units of 1019 n/cm2 goe E > 1 MeV.

In every case, Equation 1 yields a lower RTPTS'value than Equation 2.

Lower Lower Inter Inter Shell Shell Shell Shell Weld C5583-1 B9983-1 C5582-1 C5587-1 Metal I(*F)*

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+10 0

+10

-20 M(*F) 48 48 48 48 48 Cu(w/o)*

0.15 0.16 0.12 0.15 0.06 Ni(w/o)*

0.60 0.62 0.58 0.56 0.97 f(101' n/cm )

Current: 0.387 EOL:

2.89 2

RTPTS(*F)

Current 119.2 135.3 102.8 127.6 57.9 EOL 170.5 191.1 142.2 177.7

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• Values previously submitted to the NRC staff in Reference 3.

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