ML20210P091

Safety Evaluation Re Projected Values of Matl Properties for Fracture Toughness Requirements for Protection Against PTS Events.Util Must Submit Reevaluation of Resistance Temp PTS

ML20210P091
Person / Time
Site:	Calvert Cliffs
Issue date:	02/04/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20210P050	List: ML20210P047 ML20210P091
References
NUDOCS 8702130296
Download: ML20210P091 (5)

Text

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION BALTIMORE GAS AND ELECTRIC COMPANY CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-317 AND 50-318 REGARDING 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 1 Against Pressurized Thermal Shock" (PTS Rule) which was published in the

( Federal Register on July 23, 1985, the licensee for each operating pressurized water reactor "shall submit projected values of RT surface)ofreactorvesselbeltlinematerialsbygbng(attheinnervessel 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 measure-ments or other information indicate a significant change in projected values."

By letters dated January 23, August 29 and December 9, 1986 the Baltimore Gas and Electric Company submitted information on the material properties and the fast neutron fluence (E > 1.0 MeV) of the Units 1 and 2 reactor pressure vessels in compliance with the requirements of 10 CFR 50.61. The RTp and fluence values were projected to 32 effective full power years which Mrre-sponds to a 40 year operating license with an 80% capacity factor.

EVALUATION OF THE MATERIALS ASPECTS (UNIT 1)

The controlling beltline material from the standpoint of PTS susceptibility was identified to be the intermediate shell longitudinal welds 2-203 A, B and C, weld wire heat numbers 20291 and 12008 (tandem arc). The copper and nickel contents are averages for the two weld wire heats.

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

&* $b P

6 Utility Submittal Staff Evaluation Cu (copper content, %) 0.21 0.21 Ni (nickel content, %) 0.87 0.87 I (Initial RT NDT, F) -50 -50 M (Margin, *F) 48 CF (Chemistry Factor, *F) 152.6 The controlling material has been properly identified. The justifications given for the copper and nickel contents and the initial RT are accept-able. Themarginhasbeenderivedfromconsiderationofth$Dbasesforthese values, following the PTS Rule, Section 50.61 of 10 CFR Part 50. Assuming that the reported values of fluence are correct, Equation 1 of the PTS rule governs, and the chemistry factor is as shown above.

EVALUATION OF THE FLUENCE ASPECTS (UNIT 1)

The methodology for the fluence calculation was based on the discrete ordinates code 00T 3.5 using an ENDF/B-IV based cross section set. The scattering is treated with a P approximation, an S quadrature and plant specific sources. Theinterme$iateshelllongitudi,alwelds2-203A,B,C M were identified as the controlling material for the Unit 1 pressure vessel.

The peak axial fluence on the welds is the applicable value for the estimation of RT The calculated values are conservative. The methodology, the cross sectiSN. and the approximations used are acceptable.

EVALUATION OF THE CALCULATED RT (UNIT 1)

The equation specified in 10 CFR 50.61, as applicable for the Calvert Cliffs Unit 1 plant is:

0 RT PTS = I+M+(-10+470xCu+350xCuxNi)xf .27 where: I = Initial RT = -50*F NDT M = Uncertainty Margin = 48*F CU = w/o Copper in welds 2-203 A, B, C = 0.21 Ni = w/o Nickel in welds 2-203 A, B, C = 0.87

f = peak fluence for 32 effective full power years on welds 2-203 A,- 8, C -

(E > 1.0 MeV) in units of 1018 n/cm2 = 5.33-

..Therefore:

= 0

.RTPTS -50+48+(-10+470x0.21+350x0.21x0.87)x5.37 27

= -2+152.6x1.57 = 238.2*F which is lower than 270*F, the applicable 10 CFR 50.61 screening criteria, and is acceptable.

EVALUATION OF THE MATERIALS ASPECTS (UNIT 2)

The controlling beltline material from the standpoint of PTS susceptibilit was identiffe.d to be intermediate shell plate D-8906-1.

( 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, %) 0.15 0.15 Ni (nickel content, %) 0.56 0.56 I (Initial RT NDT, F) +10 +10 M (Margin, 'F) 48 CF (Chemistry Factor, 'F) 89.9 The controlling material has been properly identified. Thejustification given for the copper and nickel contents and the initial RT are acceptable. Themarginhasbeenderivedfromconsiderationgthebasesfor N

these values, following the PTS Rule, Section 50.61 of 10 CFR Part 50.

Assuming that the reported values of fluence are correct. Equation 1 of the PTS rule governs, and the chemistry factor is as shown above.

EVALUATION OF THE FLUENCE ASPECTS (UNIT 2)

The methodology for the fluence calculation was based on the discrete ordinates code DOT 3.5 using an ENOF/B-IV based cross section set. The scattering is treated with a P approximation, 3 an $8 quadrature and plant

- o I specific sources. The intermediate shell plate D8906-1 was identified as the controlling material (Reference 2). The peak axial and azimuthal fluence is the applicable value for the estimation of RT The calculated values are conservative. Themethodology,thecrossseckIhn.s and the approximations used are acceptable.

. EVALUATION OF THE CALCULATED RTog (Unit 2)

The equation specified in 10 CFR 50.61, as applicable for the Calvert Cliffs Unit 2 plant is:

0 l RT PTS = I+M+(-10+470xCu+350xcuxNi)xf .27

where

I = Initial RT NOT = 10'F M = Uncertainty Margin = 48"F

. CL = w/o Copper in shell plate D8906-1 = 0.15 Ni = w/o Nickel in shell plate D8906-1 = 0.56 l f = peak azimuthal fluence on shell plate 08906-1 for 32 effective full power i years of operation (E > 1.0 MeV) in units of 1018 n/cm2 = 5.33 Therefore: ,

= 0 RT PTS 10+48+(-10+470x0.15+350x0.15x0.56)x5.33 27

= 58+89.9x1.571 = 199.2*F which is lower than 270'F, the applicable 10 CFR 50.61 screening criteria, and is acceptable.

CONCLUSIONS v

{~ ThelicenseehascalculatedRT@y,aluesof238.2*Fand199.2'FforCalvert Cliffs Units 1 and 2, respecti for the pressure vessel plate material at j the end of 32 EFPY. This is less than 270*F which is the screening criteria for the limiting material at the expiration of the license. The Commission finds this to be acceptable. However, to permit the staff to confirm the licensee's projection of the estimated RT throughout the lives of the PTS

r-operating licenses of Calvert Cliffs Units 1 and 2, the licensee must submit a re-evaluation of the RT and a comparison to the current prediction along withthefuturePressure-fdhperatureoperatinglimitswhicharerequiredby 10 CFR 50 Appendix G.- It should be noted that this reevaluation is a require-

' ment by 10 CFR 50.61, whenever core loadings, surveillance measurements, or

..other information indicate a significant change in project values.

,Dat'e: February 4, 1987 Major Contributors:

P. Randall L. Lois O

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