ML20083G724
| ML20083G724 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/13/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20083G723 | List: |
| References | |
| NUDOCS 8401120179 | |
| Download: ML20083G724 (4) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION E
WASHINGTON, D. C. 20555 i
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTCR REGULATION RELATED TO AMENCMENT NO. 75 TO FACILITY OPERATING LICENSE NO. CPR-66 CUOUESNE LIGHT COMPANY CHIO EDISON COMPANY PENNSYLVANIA POWER CCMPANY BEAVER VALLEY POWER STATION, UN!T NC. :
DOCKET NO. 50-334 BACKGROUND As result of two consecutive incidents that occurred at Beaver Valley Unit No. 1 on May 24, 1983 which affected both redundant trains (A & B) of the onsite AC power distribution, the resident inspector requested the licensee to review the pertinent portion of the limiting condition for operation (LCO) of the technical specification (TS) for clarity and to evaluate whether it is clearly stated which one of the two action statements (LCO 3.8.2.1 vs 3.0.3) is appropriate.
Subsequent review by the licensee resulted in a TS change request dated July 14. 1983.
i SYSTEM DESCRIPTION To supply power to the safety related Class IE equipment, Beaver Valley's onsite AC distribution system employs a typical redundant division (Train A & B) where each train consists of a 4160-volt bus (I AE for Train A and IDF for Train B). Each bus is powered by an emergency diesel generator. Bus IAE 8401120179 831213 PDR ADDCK 05000334 P
supplies 480-volt emergency bus 8N while the redundant 4160-volt (IDF) bus supplies power to 480-volt emergency bus 9P. The 480-volt emergency (8N) bus serves the two 120-volt AC vital bus channels I and III of Train A while channel II and IV are cerved by' bus 9P of Train B.
EVENT On May 24,1983 the normal power supply to the 4160 volt bus 10F was interrupted at 9:55AM when a stray test signal was passed through inadvertently and operated 1010 circuit breaker (incoming power supply to IDF 4160V bus) while performing the station service transformer (TR-1B) test. When breaker 1D10 opened (Train B lost its power supply), the No. 2 emergency diesel ge'nerator started and emergency loads were properly sequenced on without initiating a reactor trip. Since offsite power was available, normal system alignment routine followed which required stripping emergency load, tripping No. 2 diesel geaerator output breaker, and closing the 4160-volt 1010 bus circuit breaker.
Based on that event, the LCO 3.8.2.1 was applicable and its action statement calls for the inoperable bus to be restored to operable status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
Consequently, Beaver Valley returned to normal system condition within the prescribed time interval.
The inspection report (83-10) dated June 14, 1983 by the Region I indicated that the licensee's action was adequate.
However, at about 1:27 Pli on the same day, the licensee received a vital bus channel I (Train A) trouble alarm. An investigation indicated that the
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channel I vital bus voltage dropped to 110 volts due to a blown capacitor in the inverter.
Later the power supply was restored by switching to the alternate power source while replacing the blown capacitor with a spare.
The system returned to normal about 3:00 PM.
EVALUATION In view of two unrelated events which affected botn trains under two different causes, the resident inspector requested the licensee to review their existing LCO and applicable action statement. They found that their existing LC0 lacks clarity on the assignment of trains. As an example, because each of the 480-volt emergency buses is designed to deenergize upon a loss of its respective 4160-volt emergency bus, there. is a remote possibility for an operator to misinterpret the above event with one 4160-volt emergency bus (Train A) and one 480-volt bus on Train B as a single train failure. To prevent occurrence of such a postulated event, the licensee requested a change to clearly identify the affected trains (s),
thus the operator can decide which action statement is appropriate.
The proposed amendment (8ti) will clearly identify the assianed ESF train boundary with respect to the 480-volt buses and allow the operator to respond according to a proper action statement.
In addition, this change conforms with the LCO 3.8.3.1 of the standard TS.
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In addition, the licensee has requested that Figure 6.2-1 of the Technical Specifications be upgraded to include the organization ander the Manager of Nuclear Engineering, and to change the job title of the Director 'of Personnel i
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Administration to Superintendent, Personnel Administration. These changes are all admini.strative in nature, have no safety significance, and are thus accepta ble.
Other changes requested in the licensee's July 14, 1983 letter will be :.
4 addressed in future amendments.
Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this
, determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed mar.ner, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
i Date: December 13,1983 Principal Contributor:
P. Kang
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