ML20138G734
| ML20138G734 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 09/26/1985 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20138G723 | List: |
| References | |
| TAC-59821, TAC-59822, NUDOCS 8510250595 | |
| Download: ML20138G734 (5) | |
Text
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r 7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION DUQUESNE LIGHT COMPANY, ET AL.
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BEAVER VALLEY UNIT 2 j
DOCKET NO. 50-412 ENVIRONMENTAL ASSESSMENT AND i
FINDING 0F NO SIGNIFICANT IMPACT i
The U.S. Nuclear Regulatory Commission (the Commission) is considering I
issuance of an Exemption from a portion of the requirements of General Design Criterion (GDC) 4 (10 CFR 50, Appendix A) to the applicants
- for Beaver Valley Unit 2, located at the applicants' site in Beaver County, Pennsylvania.
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ENVIRONMENTAL ASSESSMENT:-
Identification of Proposed Action: The Exemption would permit the applicants not to install the pipe whip restraints and jet impingement shields and not to consider the dynamic effects associated with postulated pipe breaks in the Beaver Valley Unit 2 primary coolant system, on the basis of advance calculational methods for assuring that piping stresses would not result in i
rapid piping failure; i.e., pipe breaks.
- The applicants are Duquesne Light Company, Ohio Edison Company, the Cleveland Illuminating Company and the Toledo Edison Company.
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t Need for Proposed Action: The proposed Exemption is needed in order for the applicants not to consider the dynamic loading effect;s associated
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l with the postulated full flow circumferential-and longitudinal pipe ruptures in the main loop primary coolant system. These dynamic loading effects include pipe whip, jet impingement, asymmetric pressurization transients and l
break associated dynamic transients in unbroken portions of the main loop and connected branch lines.
Therefore, the applicants would not be required to l
install protective devices such as pipe whip restraints and jet impingement shields related'to postulated break locations in the primary coolant loops.
I Analysis shows that the pipe breaks, which these devices are designed to protect against, are extremely unlikely. On the other hand, the presence of these devices increase inservice inspection time in the containment and their elimination would lessen the occupational doses to workers and facilitate t
l inservice inspections.
GDC 4 requires that structures, systems and components important to j
safety shall be appropriately protected against dynamic effects including the effects of discharging fluids that may result from equipment failures, up to l
and including a double-ended rupture of the largest pipe in the reactor l
coolant system (Definition of LOCA).
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
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l grow to critical or unstable sizes which could lead to large break areas i
l such as the double-ended guillotine break or its equivalent.
The NRC staff has reviewed and accepted the applicants' conclusion. Therefore, the NRC staf f l
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agrees that 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 shields; 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 j
for the restraints and shields to be eliminated in calculating accident doses to the environment. While the jet impingement barriers and pipe whip restraints would minimize the damage from jet forces and whipping from a broken pipe, the calculated limitation on stresses required to support this 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 shield would have no significant effect on the overall plant accident risk.
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 l
that there are no significant radiological or non-radiological impacts l
associated with the Exemption.
l The proposed Exemption involves design features 1ocated entirely within the restricted area as defined in 10 CFR 20.
It does not affect plant non-radioactive effluents and has no other environmental imp 3ct. Therefore, the Commission concludes that there are no non-radiological impacts associated l
with this proposed Exemption.
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. Since we have concluded that there are no measurable negative environmental impacts associated with this Exemption, any alternatives would not provide any significant additional protection of the environment.
The alternative to 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 (0perating License) for Beaver Valley Unit 2.
Agencies and Persons Contacted: The NRC staff reviewed the applicants' request and applicable documents referenced therein that support this Exemption for Beaver Valley Unit 2.
The NRC did not censult other agencies or persons.
FINDING OF NO SIGNIFICANT IMPACT The Commission has determined not to prepare an environmental impact statement for this action.
Based upon the environmental assessment, we conclude that this action will not have a significant effect on the quality of the human environment.
l For details with respect to this action, see the requests for exemption dated February 24, May 31, July 16, and November 5, 1984, and July 9, 1985.
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 Local Public Document Room at the B. F. Jones Memorial Library, 663 Franklin Avenue, l
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_ Aliquippa, Pennsylvania 15001. The staff's technical evaluation of the 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 26th day of September,1985.
FOR THE NUCLEAR REGULATORY COMMISSION f
/6 Thomas M. Novak, Assistant Director for Licensing Division of Licensing h"i" LB#3/
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