ML20092C323
| ML20092C323 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 06/07/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20092C322 | List: |
| References | |
| NUDOCS 8406210124 | |
| Download: ML20092C323 (2) | |
Text
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UNITED STATES og 8
6 NUCLEAR REGULATORY COMMISSION r.
j wAsHWGTON, D. C. 20586
%,..... p SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 58 AND NO. 40 TO FACILITY OPERATING LICENSE NOS. NPF-4 AND NPF-7 i
VIRGINIA ELECTRIC AND POWER COMPANY _
OLD DOMINION ELECTRIC COOPERATIVE NORTH ANNA POWER STATION, UNITS NO. 1 AND NO. 2 DOCKET NOS. 50-338 AND 50-339
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Introduction:==
By letter dated March 15, 1984, the Virginia Electric and Power Company (the licensee) requested an amendment in the form of changes to the Technicai t
Specifications (TS) to Facility Operating Licenses No. NPF-4 and No. NPF-7 for the North Anna Power Station, Units No. I and No. 2, respectively.
The proposed changes would delete the requirements for minimum and maximum temperature limits for A36 and A572_ beams in the steam generator supports and would delete verification requirements for determination of beam temperatures.
Discussion:
The NA-182 TS 3.4.10.2.a and c require that, with pressurizer pressure greater than 1000 pounds per square inch gauge (psig), _the temperature of the steam generator supports shall be greater than.85 degrees Fahrenheit ( F) for ASTM A36 beams and greater than 225*F for ASTM A572 beams. The A36 beams are monitored in the lower region of the supports at a bottom level corner, and the A572 material is monitored at a middle level corner during unit ' operation and at a top level corner during startup. TS 3.4.10.2.b also requires that the temperature monitored at the top level corner be less than 335 F.
These TS requirements were in response to the statement of the Advisory Committee on Reactor Safeguards in a partial report, dated October 26, 1976, for NA-182.
l These requirements were addressed in Section 5.4.3 of Supplement No. 6 of the NA Safety Evaluation Report, dated February 1977.
In order to achieve these elevated temperatures, the supports are now insulated by the use of tent-like enclosures and heated by resistance space heaters.
Through normal use, these blankets have become contaminated and have deteriorated l
to the degree that replac.ement of all blankets will be required every 7 years i
over the remaining life of NA-1&2. Continued use of these blankets would result in an estimated occupational dose exposure of 50 man-rem per year.
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Subsequent to the issuance of the NA-142 TS for elevated temperatures for steam generator supports, this matter, was identified by the NRC as unresolved safety Issue A-12, " Potential for Low Fracture Toughness and Lamellar Tearing in PWR Steam Generator and Reactor Coolant Pump Supports," the resolution of which is summarized in NUREG-0577, Revision 1, bearing the same title and published October 1983.
Evaluation:
The staff concurs with the licensee's request for deleting the steam generator TS requirements addressed above. The basis for the staff's concurrence with the TS revision is presented in NUREG-0577, Revision 1, Appendix C, " Valve l
Impact Analysis for A-12; Potential for Low Fracture Toughness and Lamellar Tearing in PWR Steam Generator and Reactor Coolant Pump Supports," wherein the staff concluded (Section 2.1) that corrective measures such as heating of steam generator supports should not be required for operating PWRs. Therefore, we find the licensee's proposed change for deleting the minimum and maximum temperature limits for A36 and A572 beams in the steam generator supports and verification requirements for detennination of beam temperatures to be acceptable.
The deletion of these TS requirements will no longer require the use of in-sulating tents, and removal of these tents will augment the licensee's ability to maintain individual occupational doses at as low as is reasonably achievable levels and within the limits of 10 CFR Part 20.
Environmental Consideration:
We have determined that the amendments are administrative in nature and do not authorize a change in effluent types or total amounts nor an increase-in power level and will not result in any significant environmental impact. Having made this determination, we have further' concluded that the amendments involve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 651.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the amendments.
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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, aid (2) such activities will be conducted in compliance with the Consnission's regulations' and the issuance -
i of the amendments will not be inimicel to the common defense and security or i
to the health and safety of the public.
Date:
June 7, 1984 Principal Contributors:
J. Halapatz L. B. Engle 1'
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