ML20040G512
| ML20040G512 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/26/1982 |
| From: | Prevatte R Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20040G511 | List: |
| References | |
| NUDOCS 8202160201 | |
| Download: ML20040G512 (3) | |
Text
r p
R: view Branch: Power Systems Reviewer:
R. Prevatte i.
ENCLOSURE SAFETY EVALUATION COOPER NUCLEAR STATION DOCKET NO. 50-298 ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES Introdu dion and Summary Nebraska Public Power District (NPPD) was requested by NRC letter dated August 8,1979 to review the electric power system at Cooper Nuclear Station.
The review was to consist of:
(1) Determining analytically the capacity and capability of the offsite power system and onsite distribution system to automatically start as well operate all required loads within their required voltage ratings in the event of (a) an anticipated transient, or (2) an accident (such as LOCA) without manual shedding of any electric loads.
(2) Determining if there are any events or conditions which could result I
in the simultaneous or, consequental loss of both required circuits from the offsite network to the onsite distribution system and thus violating the requirements of GDC 17.
The August 8,1979 letter included staff guidelines for performing the required voltage analysis and the licensee was further required to. perform a f
test in order to verify the validity of the analytical results. NPPD responded by letters dated December 27, 1979, August 11, 1980 and May 4,1981.
A detailed review and technical evaluation of the submittal was performed by Lawrence Livermore Laboratory (LLL) under contract to NRC, and with
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This work was reported by LLL's Technical general supervision by NRC staff.
Evaluation Report (TER) " Adequacy of Station Electric Distribution System We have reviewed Voltage, Cooper Nuclear Station" dated October 7,1981.
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' i this report and concur in the conclusions that the offsite power system and onsite distribution system are capable of providing acceptable voltages at the terminals of the Class lE equipment for worst case station electric load and grid voltages.
EVALUATION CRITERIA The criteria used by LLL in this technical evaluation of the analysis include General Design Criteria (GDC) 5 (" Sharing of Structures, Systems, and Components"), GDC 13, (" Instrumentation and Control") and GDC 17, (" Electric Power Systems") of Appendix A to 10 CFR 50; IEEE Standard 308-1974 (" Class lE Power Systems for Nuclear Power Generating Stations"); ANSI C84.1-1977 (" Voltage Ratings for Electric Power Systems and Equipment - 60 Hz"); and the staff positions and guidelines in NRC letter to NPPD dated August 8,1979.
ANALYSIS AND TEST FEATURES NPPD has analyzed each offsite power source to the onsite distribution 1
system under expected maximum and minimum grid voltages and loading conditions.
An additional analysis was conducted to evaluate the effects on Class lE system from starting a large non-Clar s-lE motor with the Class lE buses fully I
I loaded.
It has been established that the emergency 4KV and 480 volt loads will operate within allowable limits for the worst cases noted above. This is in compliance with GDC 17. The voltage analysis was verified by measuring voltages and loads at various Class lE and non-Class lE buses with the 4160V Class lE bus loaded to 65%. The comparison showed the calculated voltage for the Class 1E buses are within + 4% of the measures voltage, and are acceptable.
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l Conclusions We have reviewed the LLL Technical Evaluation Report and concur in tthe findings that:
(1) Under worst case conditions, the Class lE equipment will automatically start and continue to operate within their design voltage ratings.
(2) The voltage at the Class lE equipment will not exceed the upper design voltage rating under maximum offsite voltage and minimum plant loading conditions.
(3) The analysis submitted was verified by tests and the test data shows the analytical results to be acceptable.
(4) Based upon the information provided by the licensee no violation of GDC 17 exists.
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