ML20045E489
| ML20045E489 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 06/18/1993 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20045E461 | List: |
| References | |
| 50-395-93-16, NUDOCS 9307020141 | |
| Download: ML20045E489 (2) | |
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ENCLOSURE 1 NOTICE OF DEVIATION i
South Carolina Electric & Gas Company Docket No.: 50-395 V.C. Summer License No.: NPF-12 During an NRC inspection conducted on March 2-April 3,-1992, a safety significant deviation from a written commitment was identified.
In accordance 6
with the " General Statement of Policy and Procedure for NRC Enforcement Actions," 10 CFR Part 2, Appendix C, the deviation is listed below:
For approximately 45 electric penetrations at V.C. Summer, only one protection (primary) was provided for the full range of possible fault currents and times that would exceed the penetration damage ratings. A second (backup) protection was included which protected against the maximum fault current; however, it did not provide protection in the overload or low level fault region. The approximately 45 penetrations lacking two (dual) full protections included the penetrations for containment loads such as Reactor Building Cooling Units and Pressurizer Heaters.
1.
In the FSAR, the licensee indicated that the recommendations included in Regulatory Guide (RG) 1.63, Rev. 1, were satisfied in the V. C. Summer design.
RG 1.63 indicates that the electric penetration assemblies should be designed to withstand, without loss of mechanical integrity, the maximum short-circuit vs. time conditions that could occur given random failures of circuit over-load protective devices.
IEEE Std. 308-1971, which the FSAR indicates is also applicable to the V. C. Summer licensing basis, requires that protective devices shall be provided to isolate failed equipment automatically.
Given the above, the protection of containment over-current protective devices should extend over the full range of fault currents and overload currents the devices could be exposed to based on the system configuration. As described in NRC inspection report 395/92-04, NRC inspectors found that this degree of protection was not provided for the subject approximately 45 penetrations at Summer.
2.
In response to the NRC's FSAR Question 040.72 D, "No single failure shall cause excessive currents in the penetration conductors which shall degrade the penetration seals," the licensee indicated that no single failure would cause excessive currents in penetration conductors which would degrade the seals.
The licensee did not meet the above commitment since the back-up breaker will not provide protection for permanent overloads and low-level faults.
9307020141 930618 gDR ADOCK 05000395 PDR
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South Carolina Electric & Gas Co.
2 Docket No.: 50-395 V. C. Summer License No.: NPF-12 i
3.
The licensee indicated in the FSAR, Appendix 3A, that the penetra-tion conductors have short-time over-load and short-circuit ratings consistent with the characteristics of the back-up protective device, assuming the failure of the primary protective device. However, based on the above finding, the NRC concludes that the penetration conductors do not have short-time over-load ratings consistent with the characteristics of the back-up r
protective device when the main incoming breaker is used as the back-up protective device.
4.
In the Safety Evaluation Report the NRC accepted the licensee's approach of using the main incoming (bus) breaker as the backup protective device for electric penetration overcurrent protection, provided it would be coordinated with the primary feeder breakers.
Based on the findings stated above, the NRC concludes that the licensee did not provide properly coordinated breakers (primary and backup) for the penetration conductor protection.
Please provide to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555, with a copy to the Regional Administrator, Region II, and if applicable, a copy to the NRC Resident Inspector, in writing within 30 days of the date of this Notice, the reescas for the deviation, the corrective steps which will be taken to avoid further deviations, and the date when your corrective action will be completed. Where good cause is shown, consideration will be given to extending the response time.
Dated at Atlanta, Georgia this 18th day of June 1993 i
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