ML20140B441

Forwards Assessment of Projected Pressurized Thermal Shock Ref Temps of Reactor Beltline Matls Through 32 Efpys,Per Requirements of 10CFR50.61.Implementation of Requirements of 10CFR50.61 Complete

ML20140B441
Person / Time
Site:	Sequoyah
Issue date:	01/21/1986
From:	Domer J TENNESSEE VALLEY AUTHORITY
To:	Harold Denton Office of Nuclear Reactor Regulation
References
REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR NUDOCS 8601270009
Download: ML20140B441 (2)

Text

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. TENNESSEE VALLEY AUTHORITY

'"^"Wf8h Yo"o18M9 fa'c'e '

January 21, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Denton:

In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 This is in reference to our efforts at Sequoyah Nuclear Plant (SON) to meet the requirements of 10 CFR 50.61, " Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock (PTS)." As specified in paragraph (b)(1), enclosed is an assessment of projected PTS reference temperatures (RTpts) of SON's reactor beltline materials from the current time through 32 effective full power years (i.e., considerably past the expiration date of the operating license).

Since all values of RTpts fall within the specified PTS screening criteria through the expiration date of the SQN operating license, this completes our implementation of the requirements of 10 CFR 50.61. If pertinent information indicates a significant change in projected RTpts values, we will update our response as necessary.

Very truly yours, TENNESSEE VALLEY AUTHORITY f..d.An A. Domer Manager of Licensing SubscrJbeA and swor to before me this c//'fE day of _ _1986.

Notary Public MyCommissionExpiresh- N ,

Enclosure AD - J. MIGHT (1tr only)

EB (BALLARD) cc (Enclosure): EICSB (HOSA)

U.S. Nuclear Regulatory Commission pg ggg g gg) fl . J. Nelson Grace, Regional Administrator "f" g ffy )

101 Marietta Street, Suite 2900 Atlanta, Georgia 30323 Mr. Carl Stable Sequoyah Prorject Manager l ,\,

U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue j

Bethesda, Maryland 20814 6 12{ g y 7 ' qual opportunity Employer

J ENCLOSURE

, SFQUOYAH NUCLEAR PLANT'S RESPONSE TO 10 CFR 50.61 - FINAL RULE

+

The final rule specifies screening criteria of 2700F for base materials and axial welds and 3000F for circumferential welds and requires that reference temperatures (RTPTSs) be calculated and evaluated to these criteria. The RTPTSs are projected for the inner vessel surfaces of the beltline materials from the time of submittal to the expiration

! date of the operating license as required by 10 CFR 50.61. The basis J

for these projections are as follows.

)i RTPTS Projections for the beltline materials are sensitive to copper 4

content, nickel content, and initial RTNDT. The beltline materials I

! in units 1 and 2 consist of intermediate forgings, lower forgings, and ,

intermediate-to-lower forging circumferential welds. The copper contents, nickel contents, and initial RTNDTs for units 1 and 2 beltline materials are presented below. .

Cu Ni Initial RTNDT (1)

Uni t 1 (Percent) (Percent) (OF)

Intermediate Forging 0.15(2) 1,00(3) 40 Lower Forging 0.13(4) 0.76(4) 73 Circumferential Weld 0.33(4) 0.17(4) -40 Unit 2 Intermediate Forging 0.13(5) 0,74(5) 10 Lower Forging 0.14(2) 1,00(3) s -22 Circumferential Weld 0.13(5) o,11(5) -4 (1)These initial RTNDTs are measured values based on Charpy V-notch test and dropweight test. These values are taken from tables 5.2.4.1 and 5.2.4.2 of the Final Safety Analysis Report (FSAR).

1 -

(2)1hese values are taken from tables 5.2.4.2 of the FSAR.

(3)This value is the maximum nickel content allowed by SA-508, class 2 forging material specifications. i (4)These values are taken from WCAP-8233 "Sequoyah Unit 1 Reactor Vessel Radiation Surveillance Program," December 1973. I (5)These values are taken from WCAP-8513. "Sequoyah Unit 2 Reactor Vessel Radiation Surveillance Program," November 1975.

The projected RTPTSs are also a function of accumulated neutron fluence

at the inner surf aces of the beltline materials. The best estimate peak neutron fluence at the inner surf aces of the beltline s.aterials at i end-of-life (expiration of operating license) in taken to be 3.01 x 1019 n/cm2 . This value is a calculated design basis fluence level for end-of-life

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4 ..

. i

1 and is derived from the results of surveillance testing reported in WCAP-10340, " Analysis of Capsule T from the Tennessee Valley Authority Sequoyah Unit 1 Reactor Vessel Radiation Surveillance Program," and  !

WCAP-10509, " Analysis of Capsule T from the Tennessee Valley Authority I Sequoyah Unit 2 Reactor Vessel Radiation Surveillance Program." End-of-life is taken to be 32 effective full power years (EFPY), and this is based on a 40-year design life and an 80-percent capacity factor.

Thus, the best estimate peak gutron fluence at the inner surface per EFPY is taken to be 9.41 x 10 n/cm . The current EFPYs, current l fluences, plus 3 EFPY fluences and 32 EFPY fluences for units 1 and 2 l

are presented below.

Current Currentgluence +3 EFPY Fguence 32EFPYFguence EFPY (n/cm ) (n/cm ) (n/cm )

Unit 1 2.8521 2.68 x 10 18 5.50 x 1018 3.01 x 1019 Unit 2 2.4575 2.31 x 10 18 5.13 x 10 18 3.01 x 10 19 The projected RTPTSs for units 1 and 2 beltline material were determined by using equation 1 in 10 CFR 50.61, paragraph (b) (2), and the resulting values are presented below.

RTne(OF)

Unit 1 Current +3 EFPY 32 EFPY Intermediate Forging 167 184 s 240 Lower Forging 181 194 236 Circumferential Weld 123 148 230 Unit 2 Intermediate Forging 115 129 172 Lower Forging 97 113 167 Circumferential Weld 82 91 120 The projected end-of-life RTPTSs for the forgings meet the screening criteria of 2700F, and the projected end-of-life RTPTSs for the circumferential welds meet the screening criteria of 3000F. Upon significant changes to surveillance measurements, or other information indicating a need for updated projections, a revised response will be provided.

J