ML18005A188
| ML18005A188 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 10/30/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18005A187 | List: |
| References | |
| NUDOCS 8711030363 | |
| Download: ML18005A188 (5) | |
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UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 1.0 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO, 2
TO FACILITY OPERATING LICENSE NO.
NPF-63 CAROLINA POWER 8( LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PL'ANT, UNIT 1 DOCKET NO. 50-400 INTRODUCTION By letter dated October 15, 1987, the Carolina Power 5 Light Company (the licensee) requested an exigent change to the Technical Specifications (Appendix A to Facility Operating License No.
NPF-63) for the Shearon Harris Nuclear Power Plant, Unit 1.
- However, by letter dated October 29,
- 1987, the licensee requested that this amendment be processed as an emergency amendment.
The proposed change would revise Technical Specification 4.8. 1. 1.2.f.ll to ensure that during a diesel generator full load rejection
- test, the diesel generator voltage does not exceed 110 percent of the diesel generator voltage at the start of the test, rather than the limiting value of 7590 volts currently stipulated in the Technical Specifications.
2.0 DISCUSSION AND EVALUATION With the plant in MODE 5 (cold shutdown),
the licensee, on October 13, 1987, attempted to conduct an 18 month surveillance test on diesel generator 1B-SB.
The objective of the surveillance requirement is (1) to demonstrate that a load rejection between 6200 and 6400 kw does not result in an emergency diesel generator overspeed trip, and (2) to ensure that the voltage regulator is functioning correctly such that the diesel generator is available in the event it is needed immediately following a load rejection.
While performing this full load rejection test on October 13, 1987, the diesel generator voltage reached 7850 volts which exceeded the 7590 volt limit stipulated in the Technical Specifications.
The 7590 volt value is based on,llO percent of the nominal diesel generator starting voltage of 6900 volts.
Typically, during a generator load rejection, the diesel generator voltage increases momentarily to some higher value, but usually less than the 110 percent of the starting voltage and then decreases to the no-load values.
- Thus, a specific maximum voltage value should take into consideration the initial generator starting voltage value which could be higher than the previously assumed nominal value of 6900 volts.
However, the voltage regulator did function properly since the generator voltage of 7850 volts did not exceed 8085 volts, which is 110 percent of the generator starting
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voltage of 7350 volts existing at the time of the test.
Since the initial starting voltage of the diesel generator is linked to the grid voltage at the time of the test, it may be above the nominal 6900 volts depending on load requirements of the licensee's power grid.
This situation cannot be avoided since the diesel generator must be paralleled to the offsite grid in order to achieve the initial loading requirement (6200-6400 kw) specified in the Technical Specifications.
The proposed change to Specification 4.8. 1. 1.2.f. 11 will limit the generator voltage to less than or equal to 110 percent of the voltage on the generator at the start of the test instead of the limiting value of 7590 volts currently required by the Technical Specifications.
Furthermore, the proposed change is within the design capability of the diesel generator.
The staff finds the proposed change acceptable based on information contained in the licensee's submittal as discussed above.
The staff has accepted 115 percent of nominal voltage as a value in the standard Technical Specifications.
3.0 EXIGENT OR EMERGENCY CIRCUMSTANCES Originally, this proposed change fell into the category of an exigent change, since absent this change, diesel generator 1B-SB would have to be declared inoperable in operational modes 1 through 4.
This would have significantly impacted the licensee's estimated schedule for return to service on November 4, 1987.
The licensee had no previous reason to suspect that failure of this surveillance requirement would occur.
Previous testing was performed when system grid demand was much higher and, therefore, system voltage and diesel generator voltage were proportionally lower.
As such, sufficient margin existed to successfully perform the surveillance requirement.
Subsequently, the licensee, by letter dated October 29,
- 1987, requested that the amendment be processed as an emergency amendment to allow the plant to enter operational MODE 4 now scheduled for the evening of October 30, 1987.
Therefore, an emergency license amendment is required to be issued in order to avoid delay of startup of the unit.
The staff has reviewed the licensee's explanation of the circumstances justifying consid-eration of this amendment on an emergency basis.
Based on this review, the staff finds that the licensee used its best efforts to apply for the subject amendment in a timely manner and that it had not acted in a manner as to create the emergency to take advantage of these procedures.
4.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION The Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazards consideration exists.
A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not:
(1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possi-bility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
The licensee has reviewed this request and determined, and the NRC staff concur, that:
A.
The proposed amendment does not involve a significant increase in the probability or consequences of any accident previously evaluated because the change does not affect the method in which the diesel generators, or any other safety system, perform their intended safety function.
Diesel generator and voltage regulator operability is still ensured and the intent of Surveillance Requirement 4.8.1. 1.2.f. ll to verify the ability of the diesel generator to perform satisfactorily during a full load rejection is still fulfilled by the revised surveillance requirement.
The revision merely allows operational flexibilityto perform the required surveillance without reliance on system grid voltage conditions.
B.
The proposed amendment does not create the possibility of a new or different kind of accident than previously evaluated.
As stated
- above, no physical change to any safety related
- system, nor change in the method in which any safety system performs its intended function result from the proposed amendment.
Therefore, the proposed amendment cannot create the possibility of a new or different kind of accident than previously evaluated.
C.
The proposed amendment does not involve a significant reduction in a margin of safety.
Diesel generator and voltage regulator operability and the ability to incur a load rejection without a diesel generator overspeed trip or excess voltage is adequately ensured by the revised surveillance requirement.
As such, the margin of safety is not affected by the proposed amendment.
Based on the review of the licensee's submittal, the staff has made a
final determination that the. licensee's amendment request does not involve a significant hazards consideration since operation of Shearon Harris, Unit I with the requested change would not
( I) involve a significant increase in the probability or consequences of an accident previously
- analyzed, (2) create the possibility of a new or different kind of accident from any accident previously analyzed, or (3) involve a significant reduction in a margin of safety.
- 5. 0 ENVIRONMENTAL CONS IDERATION This amendment involves a change in surveillance requirements.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission
AMENDMENT NO.
2 TO FACILITY OPERATING LICENSE NO.
NPF HARRIS UNIT 1 DISTRIBUTION:
CDocket No..50-400-NRC PDR Local PDR PD21 r/f S.
Varga G. Lainas P. Anderson B. Buckley OGC-8 D.
Hagan J.
Partlow T. Barnhart (4)
Manda Jones E. Butcher F.
Rosa 0.
Chopra ACRS (10)
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