ML20040D095
| ML20040D095 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 01/11/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20040D093 | List: |
| References | |
| GL-81-14, NUDOCS 8201300134 | |
| Download: ML20040D095 (2) | |
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SAFETY EVALUATION REPORT s
BEAVER VALLEY UNIT 1 SEISMIC QUALIFICATION OF THE AUXILIARY ILLDWAILR SThitM I.
Introduction and Background On August 8.1980, the Division of Safety Technology (DST) transmitted the results of a study on the seismic capability of decay heat removal systems to the Division of Licensing (DL). That study included a simplified probabilistic risk analysis and recomendation for action l
by DL. Since August 1980, this subject has been the topic of additional correspondence relative to NUREG-0667. " Transient Response of Babcock and Wilcox-Designed Reactors." and has been discussed at several ACRS meetings and at planning sessions with DL and the Office of Nuclear Regulatory Research (RES). As a result of these concerns, and to assure conformance of each plant with General Design Criteria 2 and 34 of Appendix A to 10 CFR Part 50 "Multiplant Action Plan C-14: Seismic r
Qualification of Auxiliary Feedwater Systems" was formulated.
l The purpose of this plan is to determine the extent of the seismic qualification of the auxiliary feedwater (AFW) system for all operating l
Pressurized Water Reactors (PWRs). For plants with AFW systems that are not seismically qualified. either in whole or in part, this plan ultimately involves increasing the seismic resistance of the systems in a timely, systematic manner, where necessary. Upgrading of the AFW systems will be required to the extent that is appropriate to provide reasonable assurance that they are able to function following the occurrence of earthquakes up to and including the design Safe Shutdown Earthquake (SSE) for the plant.
To identify those plants without AFW systems, or portions thereof, which have been designed, constructed and maintained (and included within the scope of seismic related IE Bulletins 79-02. 79-04. 79-07, 79-14. and 80-11. and IE Information Notice 80-21) as seismically qualified systems in accordance with the criteria for other safety-grade systems at the facility. NRC Generic Letter 81.-14. " Seismic Qualification of Auxiliary Feedwater Systems." dated February 10. 1981, was issued under 10 CFR 50.54(f) to all operating PWR licensees. This letter also requested walk-downs of the equipment, components and piping comprising those portions of the AFW system which were not designed, constructed and maintained as seismically qualified systems i
in accordance with the criteria for other safety-grade systems at the facility.
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. These walk-downs were to be performed by personnel experienced in the analysis, design and evaluations of structures, systems and compon-ents similar to those comprising the non-seismically qualified portions of the AFW system to identify any readily recognized deficiencies in seismic resistance and to recommend any appropriate remedial modifica-tions. Any corrective actions taken, or planned, were to be described, and a schedule for the planned corrective actions provided. Similar considerations as those described above were to be given to alternate decay heat removal paths in those cases where portions of the AFW system are not seismically qualified.
The bounds to be considered for these systems were defined as follows:
In responding to this letter, the AFW system boundary from suction to discharge (including the water source and heat sink) shall include those portions of the system required to accomplish the AFW system function and connected branch piping up to and including the second valve which is normally closed or capable of automatic closure when the safety function is required. The AFW system boundary shall also include any portion of branch piping that is structurally coupled to the AFW system boundary such that the seismic response of the branch piping transmits loads to the AFW system. As a minimum, this includes the branch lines outside the AFW system boundary to a point of three orthogonal restraints. All mechanical and electrical equipment, piping (e.g., instrument air), conduits and cable trays, which are necessary or contain items which are necessary, for the operation of the AFW system shall also be considered.
In addition, the structures housing these systems and components shall be included. Similar considerations shall be applied when considering alternate means of decay heat removal.
Discussion l
l Duquesne Light submitted the information requested for Beaver Valley Unit l
1 in NRC Generic Letter 81-14 via letters from J. J. Carey to Steven A.
Varga, dated August 5,1981 and November 15, 1981. This information l
indicated that:
- 1) The safety-related portions of the AFW system (including the structures within which they are housed) are designed, constructed and maintained (and included within the scope of IE Bulletins 79-02, 79-04, 79-07, 79-14, and 80-11. and IE Information Notice 80-21) in accordance with seismic criteria consistent with those for other safety grade systems in the station. The portions of the AFW system considered are consistent with the bounds defined in GL 81-14.
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