ML20140B569

Forwards Evaluation of Reactor Vessel Matls State of Toughness,Per 10CFR50.61(b).Current & Projected Rt Pressurized Thermal Shock Values Assessed Using Guidelines in Westinghouse .Plant Approved for Operation

ML20140B569
Person / Time
Site:	Yankee Rowe
Issue date:	01/22/1986
From:	Papanic G YANKEE ATOMIC ELECTRIC CO.
To:	Lear G Office of Nuclear Reactor Regulation
References
REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR FYR-86-007, FYR-86-7, NUDOCS 8601270045
Download: ML20140B569 (7)

Text

Tc'epho"c ('") 8' -* 'oo CANKEE ATOMIC ELECTRIC COMPANY TWX 710-380-7619 1

~

/ "s* 2.C.2.1 l

, 1671 Worcester Roact Framingham, Massachusetts 01701 FYR-86-007 l

, N UdfE , '

l 1

January 22, 1986 United States Nuclear Regulatory Commission Washington, DC 20555 Attention: Mr. George Lear, Director PWR Project Directorate No.1 Division PWR Licensing - A

References:

(a) License No. DPR-3 (Docket No. 50-29)

(b) Letter, Westinghouse Electric C)cporation to Yankee Atomic Electric Company, " Pressurized Thermal Shock Rule," dated July 26, 1985 (c) S. L. Anderson, " Analysis of Fast Neutron Flux Levels and End-of-Life Exposure for the Yankee Rowe Reactor Pressure Vessel," Westinghouse Electric Corporation, March 1981 (d) " Fracture Toughness Requirements for Older Plants,"

Standard Review Plan, Branch Technical Position MTEB 5-2 (e) "NRC Staff Evaluation of Pressurized Thermal Shock,"

November 1982 (Enclosure A to SECY-82-465)

Subject:

Pressurized Thermal Shock Rule - 10CFR50.61(b)

Dear Sir:

Yankee is required under 10CFR50.61(b) to establish the toughness state of the Yankee reactor vessel materials for pressurized thermal shock considerations by January 23, 1986.

An evaluation has been performed using the guidelines in Reference (b) to assess the current and projected values of RTPTS (at the inner surface) of the Yankee reactor vessel beltline materials and is contained in Attachment A. The methodology described in Paragraph (b)(2) of 10CFR50.61 was used to calculate the values of RTPTS-The limiting reactor vessel material, based on the RTPTS correlation, is the lower vessel plate. This is due to its higher nickel content and irradiation embrittlement. The calculated maximum RTPTS is 2230F currently and 2390F at end-of-license (1997). These values are well below the PTS screening criterion of 270 0F for plate material.

Based upon the above discussion, the Yankee plant can be operated through its remaining license without significant risk resulting from pressurized thermal shock. AD - J. Knight (ltr only)

• . EB (BALLARD) 0601270045 860122 f L EICSB (ROSA)

PDR ADOCK 05000029 PSB (GAMMILL)

P PIM1 f@ RSB (BERLINGER)

F0B (BENAROYA)

United States Nuclear Regulatory Commission January 22, 1986 Attention: Mr. George Lear, Director Page 2 We trust that you will find this information satisfactory; however, should you have any questions regarding this matter, please contact us.

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY George ic, Jr Senior. Project Engineer - Licensing Yankee Project GP/dps

i ATTACHNENT A Per 10CFR 50.61(b), a determination of RT PTS has been made for Yankee from current operation through end-of-license (1997). The determination requires that the material chemistry, vessel fluence, and initial RT

• NDT established.

Chemistry For the Yankee vessel, the chemistries are listed in Table I and those of interest are summarized below:

Cu (%) Ni (%)

Upper Plate 0.18 0.18 Lower Plate 0.20 0.63 Weld 0.12 0.07 Fluence Based on a Westinghouse analysis (Reference (c)), the peak fluence accumulation rate at the ID of the upper vessel plate near the core midplane is 0.101 x 10 N/cm per Effective Full Power Year (EFPY). Due to the location of the lower plate relative to the reactor core centerline, the lower plate receives less than 89% of this peak value.

The present fluence values are given below:

Upper Plate 1.78 x 10 N/cm (E > 1.0 MeV)

Lower Plate 1.584 x 10 N/cm (E > 1.0 MeV)

Assuming a 75% plant capacity factor and operation through 1997, the fluence at end-of-license (~26 EFPY) are calculated to be:

- si l Upper Plate 2.626 x 10 N/cm (E > 1.0 MeV)

Lower Plate 2.337 x 10 N/cm (E > 1.0 MeV)

Initial RT NDT Charpy tests were conducted by the manufacturer for both vessel plate and weld material samples. All tests were performed at 10 F using longitudinal specimens with none resulting in less than 30 ft-lbs. Initial RT

• NDT Pl ate material was corrected per Reference (d) by adding 20 F to compensate for the lack of transverse-oriented specimens. The initial RT f r the NDT weld remains 10 F since these specimens are isotropic. A sunurary of RT NDT and Charpy test values is prcvided in Table 2.

RT g3 Values RT is calculated as prescribed in 10CFR50.61(b). RT as defined in PTS PTS 10CFR50.61(b)(2) is the lower of the results given by Equations 1 and 2 . In all cases, Equation 1 resulted in lower values of RT The RTpg values PTS.

are contained in Table 3.

The limiti g reactor vessel material, based on the RT rrelation is the PTS lower vessel plate. This is due to its higher nickel content and resulting increased irradiation embrittlement. This is also noted in Reference (e).

The calculated maximum RT in the limiting plate is 223 F currently and PTS 239 F at the end-of-plant-license. These values are well below the PTS screening criterion of 270 F for plate material.

Therefore, the Yankee plant can be operated through its remaining license without significant risk resulting from pressurized thermal shock.

i l'

l A J a e n- + -we ---n-,. -e--r-~ ,vn,- ,m - , ,, -e--- 4 -- - m-

TABLE 1 Reactor Vessel Shell Material Properties Wald Chemical Composition (%1 Upper Shell Lower Shell Material Supplier: Lukens Supplier: Lukens Heat No.: 19281-2 Heat No.: 19244-3 C .20 ,

.19 --

Mn 1.27 1.18 .68 P .020 .016 .01 S .028 .026 --

Si .21 .20 .20 Mo .48 .48 .02 Ni .18 .63 .07 Cu .18 .20 .12 Cr -- --

.06 V -- -- --

Al -- -- --

TABLE 2 f

Initial RT and Charpy Test Values NDT Upper Shell Lower Shell r

Heat No. 19281-2 19244-3 L

?

Charpy Test at +100F (ft-lbs)1 L52-50-46 L48-41.5-43 Initial RTNDT (Per NTEB 5-2) +300F +300 F'  !

I Weld To Weld To Heat No. 19281-2 19244-3 .

r Charpy Test at +10 0 F (f t-lbs)1,2 40-31-35 42-30-38 9

Initial RTNDT +10 0 F +10 0 F t

1. Preirradiation tests by Babcock and Wilcox at time of vessel fabrication. ,

Tests conducted at 1/4 thickness location.

2. Weld material is Hi-Mang Moly wire with Linde No. 80 48KD flux.

i r

4 k

k l

l l

l f l

1

TABLE 3 RT Values PTS Fluence Initial Material N/cm (E > 1.0 Mev) RTNDT ( PTS Upper Plate (Current) 1.78 x 1019 300F 1780F Upper Plate (EOL) 2.62 x 1019 300F 1890F Lower Plate (current) 1.584 x 1019 300F 2230F Lower Plate (EOL) 2.337 x 1019 300F 2390F Weld (Current) 1.78 x 1019 100 F 1160F Weld (EOL) 2.62 x 1019 100F 1220F Note: RTPTS values are calculated using Equation 1:

0 RTPTS = I + M + [-10 + 470 Cu + 350 CuNi] f .270 where:

I = measured initial reference temperature in OF M = 480F l

i 1

1 0

, . . - - . - , - - , , , - , , .- ,-m,-- . . . . ,,e.. -n-- - , - 7,-,,,