ML20236J396

Safety Evaluation Supporting Amends 106 & 96 to Licenses DPR-39 & DPR-48,respectively

ML20236J396
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	07/20/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20236J375	List: ML20236J373 ML20236J386 ML20236J396
References
NUDOCS 8708060162
Download: ML20236J396 (3)

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'o UNITED STATES

[ ([gg NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20S55 s.v

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i

RELATED TO AMENDMENT N0.106 TO FACILITY OPERATING LICENSE N0. GPR-39 AND AMENDMENT N0. 96 TO FACILITY OPERATING LICENSE N0. DPR-48 COMMONWEALTH EDIS0N COMPANY ZION NUCLEAR POWER STATION, U":TS 1 AND 2 DOCKET N05. 50-295 AND 50-304 INTRODUCTION By letter dated April 8,1987, Commonwealth Edison Company proposed amendments to Technical Specification, Section 4.3.4.D. Materials Irradiation Surveillance Specimen Inspection, at Zion Units 1 and 2. The proposed amendments provide a revised specimen capsule withdrawal schedule in the licensee's reactor vessel material surveillance program based on the staff's previous recommendation to the licensee in a letter dated January 16, 1986, from J. Norris of NRC to D. Farrar of the Commonwealth Edison Company.

DISCUSSION The exposure of a reactor vessel to the constant neutron irradiation and thermal environment changes the fracture toughness properties of ferritic materials in the beltline region of the vessel. The staff requires, as described in Appendix H of 10 CFR 50, that a reactor vessel material surveillance program be implemented to monitor vessel material property changes. The surveillance program is required to install a minimum number j of specimen capsules inside of the reactor vessel and withdraw capsules l periodically for metallurgical testing per ASTM E 185-82 guidelines. 4 The ASTM guidelines consider the following: 1) the peak vessel inside surface neutron fluence at the end of life (E0L) and the corresponding transition temperature shift; 2) the lead factor for each surveillance j capsule relative to the peak beltline neutron fluence; and, 3) the number i of effective full power years (EFPY) for the capsule to reach the peak vessel E0L fluence at the inside surface and at the i T (thickness) location. Based on staff calculations of the transition temperature shift at the vessel inside surface per Reg. Guide 1.99 Rev. 2, Zion should have a  ;

minimum of five capsules in the reactor vessel. Each of the Zion Units had I a total ;f eight capsules located at the inside of the vessel wall. j Presently, in Unit 1 the first three capsules have been removed, the fourth j capsule is still in use, and four capsules are on standby. In Unit 2, the first two capsules have been removed, the third capsule is in use, and five l

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1 capsules are on standby. According to ASTM, the fourth capsule in a reactor vessel is to be withdrawn in 15 EFPY, or when the neutron fluence for the capsule reaches E0L fluence at the vessel inner wall location. The fifth capsule is to be withdrawn when the neutron fluence for the capsule reaches the EOL peak fluence, or when the neutron fluence is in the range of once to twice I the peak E0L fluence.

In the previous staff' review on the withdrawal schedule as described in our January 16, 1986 letter, the staff accepted the licensee's withdrawal schedule of 8.5 EFPY for the fourth capsule at Unit 1 and for the third capsule at Unit 2. However, the staff recommended at that time that one additional capsule be provided in each reactor unit in order to satisfy the ASTM requirements. For this amendment, the licensee prposed to use one standby capsule from each reactor unit and withdraw them according to ASTM guidelines. For Unit 1, the fifth capsule, capsule Z, will be withdrawn in j 32 EFPY and for Unit 2, the fourth capsule, capsule X, will be withdrawn in 13 EFPY.

The earlier withdrawal of the fourth capsule in 13 EFPY from Unit 2 reactor )

is due to the implemented low leakage fuel design in the Zion reactcr vessels, which has reduced the neutron fluence at the beltline region of the vessels.

The neutron leakage reduction has resulted in a lower projected E0L neutron fluence and thus, an earlier withdrawal schedule for the fourth capsule. Also, '

because the fourth capsule will be ex,"osed to the peak E0L fluence in only 13

! EFPY, a fifth capsule is not needed for the Unit 2 surveillance program. The information on the neutron fluence was provided in the Westinghouse report WCAP-10902 and has been reviewed by the staff. For Unit 1, the fourth )

capsule will have accumulated neutron fluence corresponding to the E0L fluence at the reactor inner wall location in 8.5 EFPY. The fifth capsule  !

l willi reach the peak E0L fluence in 32 EFPY. For Unit 2, the fcurth capsule ,

will reach the peak E0L fluence in 13 EFPY. After the peak E0L fluence is l l reached, a fifth capsule is not needed.

l TECHNICAL FINDINGS Based on the staff calculations of the transition temperature shift and neutron fluence and review of the projected E0L neutron fluence, the staff concludes that the revised capsule withdrawal schedule will provide an l adequate surveillance program for the toughness data of reactor vessel material property at Zion Units 1 and 2 and that the proposed capsule withdrawal schedules comform to the ASTM guidelines. The staff approves the licensee proposed amend-ment to Technical Specifications, Section 4.3.4.0, at Zion Units 1 and 2.

ENVIRONMENTAL CONSIDERATION These amendments involve a change in the installation or use of the facilities -

components located within the restricted areas as defined in 10 CFR 20. The staff has determined that these amendments involve no significant increase in j the amounts, and no significant change in the types, of any effluents that may j be released offsite and that there is no significant increase in individual or  !

cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, these amendments meet the eligibility criteria for categorical exclusion set l fortnin10CFRSec51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental l

4 impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.

CONCLUSION We have concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance  !

of these amendments will not be inimical to the common defense and security or to the health and safety of the public.

Dated: July 20,1987 PRINCIPAL CONTRIBUTOR: J. Tsao s

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