ML20137T364
| ML20137T364 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 11/06/1985 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20137T351 | List: |
| References | |
| NUDOCS 8512060445 | |
| Download: ML20137T364 (5) | |
Text
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7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION PUBLIC SERVICE COMPANY OF NEW HAMPSHIRE, ET. AL.*
SEABROOK STATION, UNITS 1 AND 2 DOCKET NOS. 50-443 AND 50-444 ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT The U.S. Nuclear Regulatory Commission (the Commission) is considering
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issuance of an Exemption from a portion of the requirements of General Design Criterion (GDC) 4 (10 CFR 50, Appendix A) to the Public Service Company of New Hampshire, et. al. (the applicants), for the Seabrook Station, Units 1 and 2, located at the applicants' site in Seabrook, New Hsmpshire.
ENVIRONMENTAL ASSESSMENT:
Identification of Proocsed Action: The Exemption would pemit eliminating l
the need to install the pipe whip restraints and jet impingement shields and their dynamic e,ffects associated with postulated pipe breaks in eight locations per loop in th Seabrook Units 1 and 2 primary coolant systems, on the basis l
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of advanced calculational methods for assuring that piping stresses would not result in rapid piping failure; i.e., pipe breaks.
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- The current construction permit holders for Seabrook Station are: Bangor Hydro-Electric Company, Canal Electric Company, Central Maine Power Company, Central Vemont Public Service Corporation, Connecticut Light & Power Company, Fitchburg Gas & Electric Light Company, Hudson Light & Power Department Maine Public Service Company, Massachusetts Municipal Wholesale Electric Company, Montaup Electric Company, New England Power Company, New Hampshire Electric l
Cooperative, Inc., Public Service Company of New Hampshire Taunton Municipal Lighting Plant, United Illuminating Company, Vermont Electric Generation and Transmission Cooperative, Inc., and Washington Electric Cooperative, Inc.
8512060445 851122 PDR ADOCK 05000443 A
, Need for Proposed Action: The proposed Exemption is needed because GDC 4 requires that structures, systems and components important to, safety shall be appropriately protected against dynamic effects including the effects of dis-charging fluids that may result from equipment failures, up to and including a double-ended rupture of the largest pipe in the reactor coolant system (Defini-tionofLOCA).
In recent submittals the applicants have provided information to show by advanced fracture mechanics techniques that the detection of small flaws by either inservice inspection or leakage monitoring systems is assured long before flaws in the piping materials can grow to critical or unstable sizes
__ which could lead to large break areas such as the double-ended guillotine break or its equivalent. The NRC staff has reviewed and accepted the applicants' con-clusion. Therefore, the NRC staff agrees that the double-ended guillotine break in the primary pressure coolant loop piping need not be required as a design basis accident for pipe whip restraints and jet shields, and their associated dynamic effects, i.e., the restraints and jet shields are not needed. Accordingly, the NRC staff agrees that a partial exemption from GDC 4 is appropriate.
Environmental Impact of the Proposed Action: The proposed exemption would not affect the. environmental impact of the facility. No credit is given for the barriers to be liminated in calculating accident doses to the environment.
While the jet impingement barriers would minimize the damage from fet forces from a broken pipe, the calculated limitation on stresses required to support the Exemption assure that the probability of pipe breaks which could give rise to such forces are extremely small; thus, the pipe whip restraints and jet shields would have no significant effect on the overall plant acc.ident risk.
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The Exemption does not otherwise affect radiological plant effluents.
Likewise, the relief granted does not affect non-radiological plant effluents, and has no other environmental impact. The elimination of the pipe whip restraints and jet impingement shields would tend to lessen the occupational doses to workers inside containment. Therefore, the Commission concludes that there are no significant radiological or non-radiological impacts associated with this Exemption.
The proposed Exemption involves design features located entirely within the restricted area as defined in 10 CFR 20.
It does not affect plant non-radioactive effluents and has no other environmental impact. Therefore, the Commission, con-cludes that there are no non-radiological impacts associated with the proposed Exemption.
Since we have concluded that there are no measurable negative environmental impacts associated with the Exemption, any alternatives would not provide any significant additional protection of the environment. The alternative to the compliance would be to require literal compliance with GDC 4.
Alternative Use of Resources: This action does not involve the use of resources not previously considered in the Final Environmental Statement (operating licknse) for Seabrook Units 1 and 2.
Agencies and Persons Contacted: The NRC staff reviewed the applicants' request and applicable documents referenced therein that support the Exemption for Seabrook Units 1 and 2.
The NRC did not consult other agencies or persons.
FINDING OF NO SIGNIFICANT IMPACT The Commission has determined not to prepare an environmental impact state-ment for this action. Based upon the environmental assessment, we conclude that
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this action will not have a significant effect on the quality of the human environment.
For details with respect to this action, refer to the applicants' request for exemption dated August 9, 1984, February 1, 1985 and July 10, 1985. These documents, utilized in the NRC staff's technical evaluation of the exemption request, are available for public inspection at the Comission's Public Document Room, 1717 H Street, N.W., Washington, D.C.
20555, and at the Excter Public Library, Front Street, Exeter, New Hampshire 03833. The staff's technical evaluation of the exemption request. fill be published with the exemption (if the exemption is granted) and will also be available for inspection at both locations listed above.
Dated at Bethesda, Maryland, this day of 1985.
FOR THE NUCLEAR REGULATORY COMMISSION Thomas M. Novak, Assistant Director for Licensing Division of Licensing DL:LB#3 B#3 OELD DL.
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REQUEST FOR EXEMPTIONS FROM A PORTION OF GENERAL DESIGN CRITERION 4 0F APPENDIX A TO 10 CFR PART 50 REGARDING THE NEED TO ANALYZE LARE PRIMARY LOOP PIPE RUPTURES AS A STRUCTURAL DESIGN BASIS FOR SEABROOK STATION,
'JNITS 1 AND P DISTRIBUTION:
iDocket!Nos;:[50-443/444)
NRC PDR~
Local PDR PRC System LB#3 Reading JLee VNerses TMNovak JSaltzman, SAB OELD, Attorney
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, HRDenton JRutherg AToalston WMiller, LFMB JPartlow BGrimes EJordan LHarmon EButcher, SSPB TBarnhart(8)
IBailey KJabbour BDLiaw RBosnak FCherny h' Johnson FCongel DMuller i
JScinto JShapaker RWHouston JPXnight RBernero HLThompson l
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