ML17299A845
| ML17299A845 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/20/1985 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17299A844 | List: |
| References | |
| TAC-60476, NUDOCS 8512060065 | |
| Download: ML17299A845 (9) | |
Text
7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION ARIZONA PUBLIC SERVICE COMPANY, ET AL PALO VERDE NUCLEAR GENERATING STATION, UNIT I DOCKET NO.
STN 50-528 ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT The U.S. Nuclear Regulatory Commission (the Commission) is considering issuance of an Exemption from a portion of the requirements of General Design Criterion (GDC) 4 (10 CFR 50, Appendix A) to the Arizona Public Service
- Company, Salt River Project Agricultural Improvement and Power District, El Paso Electric Company, Southern California Edison Company, Public Service Company of New Mexico, Los Angeles Department of Water and Power*, and Southern California Public Power Authority (the licensees) for the Palo Verde Nuclear Generating Station, Unit I, located at the licensees'ite in Maricopa County, Arizona.
ENVIRONMENTAL ASSESSMENT:
Identification of Pro osed Action:
The Exemption would permit the licensees not to consider the dynamic effects and,
- hence, not require pipe whip restraints and jet impingement shields associated with postulated pipe breaks in the Palo Verde Unit I primary coolant system, on the basis of advanced calculational methods for assuring that piping stresses would not result in rapid piping failure; i.e., pipe breaks.
Need for Pro osed Action:
The proposed Exemption is required because GDC 4 requires that structures, systems and components important to safety shall be appropriately protected against dynamic effects including the effects of dis-1 1
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co-owner until after Palo Verde Unit I achieves commercial operation.
85120b00b5 851122 PDR ADOCK 05000528 P
PDR 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-tion of LOCA).
In recent submittals, the licensees 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 licensees'on-elusion.
Therefore, the NRC staff agrees that the double-ended guillotine break in the primary pressure coolant loop piping, and its associated dynamic effects, need not be required as a design basis accident for pipe whip restraints and jet impingement shields, i.e., the restraints and shields are not needed.
Accordingly, the NRC staff agrees that an exemption from GDC 4 is appropriate.
Environmental Im act of the Pro osed Action:
The proposed Exemption would not affect the environmental impact of the facility.
No credi t. is given for the barriers to be eliminated in calculating accident doses to the environment.
While the jet impingement barriers would minimize the damage from jet forces from a broken pipe, the calculated limitation on stresses required to support this proposed Exemption assures that the probability of pipe breaks which could give rise to such forces are extremely small; thus, the pipe whip restraints and jet impingement shields would have no significant effect on the overall plant accident risk.
The proposed Exemption does not otherwise affect radiological plant effluents.
Likewise, the relief requested 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 proposed 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 Coomission con-cludes that there are no non-radiological impacts associated with this proposed Exemption.
Since we have concluded that there are no measurable negative environmental impacts associated with this proposed Exemption, any alternatives would not provide any significant additional protection of the environment.
The alternative to granting the Exemption 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 License Stage) for Palo Verde, Unit 1.
A encies and Persons Contacted:
The NRC staff reviewed the licensees'equest and applicable documents referenced therein that support this proposed Exemption for Palo Verde, Unit 1.
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 this action will not have a si'gnificant effect on the quality of the human environment.
For details with respect to this action, see the requests dated June 7,
- 1984, and November 13 and 15, 1985, and other information provided by Combustion Engineering, Inc., in letters dated June 14, 1983 and December 23, 1983, which are referenced by the licensees.
These documents, utilized in the NRC staff's technical evaluation of the exemption request, are available for public inspection at the Commission s Public Document
- Room, 1717 H Street, N.W.,
Washington, D.C., and at the Phoenix Public Library, Business, Science and Technology Department, 12 East McDowell Road, Phoenix, Arizona 85004.
The staff's technical evaluation of the exemption request will 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 20th day of November, 1985.
FOR THE NUCLEAR REGULATORY COMMISSION Thomas M. Novak, Assistant Director for Licensing Division of Licensing DL:LBB3g Dpi~
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