ML20247N259
| ML20247N259 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/26/1989 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 89-506A, NUDOCS 8908020344 | |
| Download: ML20247N259 (4) | |
Text
_
[
VIRGINIA ELECTRIC AND POWER COMPANY RICIIMOND, VIRGINIA 23261 W.1. STE W ART SENIOR VICE PRESIDENT power July 26, 1989 U. S. Nuclear Regulatory Commission Serial No 89-506A Attn: Document Control Desk NOS/TAH:jm]
Washington, D. C. 20555 Doc'Let No. 50-338 50-339 License No. NPF-4 NPF-7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 ESF SLAVE RELAY TESTING On July 12,1989, Virginia Electric and Power Company submitted our plan for ESF slave relay testing with a proposed Technical Specification change.
During subsequent telephone conversations with the NRC's staff, we were requested to revise and resubmit the 10CFR50.92, Significant Hazards Consideration, for the proposed change. The revised Significant Hazards Consideration, which supercedes and replaces that which was submitted by the July 12,1989 letter, is attached.
If you have further questions, please contact us.
Very truly yours, Y,
W. L. STEWART
Attachment:
0l 0
80gg [
B P
u __
/
/
~
~U. S. Nuclear Regulatory Commission oc:
101 Marietta Street, N.W.'
Suite 2900 Atlanta, GA -
30323 Mr. J. L. Caldwell NRC Senior Resident inspector North Anna Power Station Mr. W. E. Holland NRC~ '3enior Resident inspector Surry Power Station 1
LL______________-___
$ V A LU ATION U NDER 10CFR50.92 FOR S IG NIFIC A NT H A Z A R' D S CONSIDERATION The proposed change requests a reduction in the number of Emergency Safety Features (ESF) slave relays to be tested during power operations at North Anna.
The request also asks that the surveillance frequency be.
changed to quarterly for those relays that will be tested at power.
NRC has established three criteria in 10CFR50.92 for determining whether a proposed amendment involves no significant hazards consideration.
No sigr.ificant hazards consideration is involved if the croposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility 'of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction 'in a margin of safety.
Regarding criterion -(1), the transients that could occur as a result of testing ESF slave relays at power have been previously evaluated.
In fact, the primary purpose for proposing this amendment was to reduce the-potential for causing transients that could challenge safety systems while operating the reactor at power.
Our assessment is that many of the ESF relay tests that under the current Technical Specification required to be performed at power created a significant potential for transients that were found to be unacceptable by Virginia Power from a nuclear safety perspective.
Therefore, we conclude that by limiting the at-power relay tests to a very select group and decreasing the frequency of testing, the proposed change does not result in a significant increase in the probability or consequences of an accident previously evaluated.
Regarding criterion (2), the majority of the ESF relays that were evaluated for on-line testing involved unusual and complex systems manipulations to accomplish the testing.
These system alignments were considered by Virginia Power to be unusual and potentially unsafe if conducted during power operations.
The limited number of relays eventually selected for testing at power were chosen to ensure, to the extent possible, that the potential impact on plant operations and the possibility of inducing some type of plant transient is minimizei Therefore we conclude that the requested change does not create and, based on our evaluation, reduces the possibility of a new or different kind of accident from any accident previously evaluated.
Fiegarding criterion (3), the safety analysis which supports this amendment request provides a thorough evaluation addressing the overall plant operational margin of safety.
It is Virginia Power's view that the submittal, as proposed, has ensured that overall plant operational safety has been preserved and may have been enhanced by the rigorous evaluation of the potential failure modes and consequences related to ESF re'ltiy testing while at power.
Therefore, we conclude that the margin of safety has not been decreased by the proposed change.
Based of our evaluation of the three criterion in 10CFR50.92, we conclude that the proposed change involves no significant hazards consideration.
l 1
)
l i
__.