ML19350C126
| ML19350C126 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/24/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19350C123 | List: |
| References | |
| NUDOCS 8103300555 | |
| Download: ML19350C126 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION
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SAFETY EVALUATION 3Y THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMEND"ENT NO. 26 TO FACILITY OPERATING LICENSE NO. NPF _4 VIRGINIA ELECTRIC AND POWER CCMPANY NORTH ANNA POWER STATION, UNIT NO. 1 DOCKET NO. 50-338
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Introduction:==
This Safety Evaluation Report related to Amendment No. 25 to Facility Operating License NPF-4 for the North Anna Power Station, Unit No.1 (NA-1) addresses changes in plant snubbers as specified in Table 3.7-4 of the NA-1 Technical Specification 3/4.7.10.
The changes involve the removal, addition and rel; cation of facility snubbers based on the ongoing NRC required multi-structure Amplified Response Spectra
( ARS) reanalysis for NA-1.
The ARS reanalysis has required in some cases the design and installation of pipe suoport modifications involving plant specific snubbers.
By letter dated March 12,1981 - and us supplemented by letter dated March 16, 1981, the Virginia Electric and Power Company (the ifcensee) requested the chan;es as noted above. These changes regarding specific snubber removal, addition and relocation and cur bases for. approval of these changes is provided below.
Discussion:
1.
Snubber Nos. WFPD-H-225 and 600 Essed on the ARS reanalysis, it has been determined that the existing snubber at location WFPD-H-225, outside the crane wall, be moved to location JPD-H-600, insida the crane wall. This requires the deletien of snubber No. 225 and the addition of snubber No. 600 in Table 3.7-4 of the NA-1 Technical Specification 3/4.7.10.
The relocation of this snubber dces not decrease the margin of t'4g since at the new location the snubber will provide greater sup".c
, the piping for. applicable loads ex::ected during a seismic event o. att vnt conditions as determined in-the ARS reanalysis.
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. 2.
Snubber Nos. WFPD-HSS-232, 233 and 234 Also, as a result of the ARS reanalysis, modifications were made to the supports for feed water piping to accommodate pipe stress and loading. The~efore, snubbers WFPD-HSS-232, 233 and 234 are no longer required and are removed. This requires the deleticn of snu bers 232, 233 and 234, at 1ccation FW-300-SB, from Table 3.7-4 of the NA-1 Technical Specification 3/4.7.10.
The combination of the piping support modifications and the deletion of these snubbers does not decrease the margin of safety since stress and applicable loads on piping expected during a seismic event or accident conditions will be reduced.
3.
Snubber Nos. WFPD-HSS-219. 220 and 221; and SI-HSS-100A and 1003 Finally, as a result of the ARS reanalysis, modifications were made to the supports of the feedwater piping system in the main steam valve house and the Safety-Injection piping in the safeguards building. These changes in-volved the replacement of snubbers WF?D-HSS-219, 220 and 221, and snubbers SI-HSS-100A and 100B with rigid supports. As a result of these changes snubbers 219, 220 and 221, at location WFDD-232-MSVH and snubbers 100A and 100B at location SI-256-SG are deleted from Table 3.7-4 of NA-1 Technical Specification 3/4.7.10.-
The combination of these changes were _made to reduce pipe stresses and loading expected on the above piping during a seismic event or accident conditions, and the replacenunt of these snubbers with rigid supports does rot decrease the margin of safety.
Evaluation:
Sased on the above, we find these changes to Table 3.4-7 of the_NA-1 Technical Specification 3/4.7.10 to be acceptable.
Environmental Consideration We have determined that the amendment does 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 amendment involves an action which is insignificant from the standpoint of
- environmental impact and, pursuant to 10 CFR Sl.5(d)(4), that an environmental impact statement or negative declaration and environ-ental-impact appraisal need not be prepared in connection with the issuance of this~ amendment.
i 3-Conclusion
' We have concluded, based on the considerations discussed above, that:
(1) because the anendment does not involve a significant increase
- in the probability or consequences of accidents previously censidered and does not _ involve a significant decrease' in a safety cargin, the
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amenc ent does not ' involve a significant hazards consideratien, (2) there is reasonable ' assurance that the health and safety of the public will not be endangered by-operation in the pecposed manner, and (3) such activities will be conducted in compliance with the Ccenission's regulations and the issuance of this amendment.will not be ininical to the common defense _ and security or to the health and saf ety of the public.
Date: March 24, 1981 e
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