ML20012D649
| ML20012D649 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/19/1990 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9003280184 | |
| Download: ML20012D649 (3) | |
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t vor Vahey Power Sttion SNppingport. PA 16077-0004 JOHN D.s$1(B(.4 I8III 00>'bEIE tst fro 0.rlt
- Nach.81 OtOup March 19, 1990 t
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,U.
S. Nuclear Regulatory Commission
'Attnt Document Control Desk Washington, DC 20555 Reference Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Temporary Waiver of Compliance Gentlement The purpose of this letter is to request retroactive NRC approval of a
Temporary Waiver of Compliance regarding Unit No. 1 Technical Specification Limiting condition for Operation (LCO) 3.8.2.1.
As a
result of recent NRC Region 1 review, the action associated-with: LCO 3.8.2.1 has been interpreted to require the plant to declare vital bus as inoperable.f it's associated inverter is not powering i
a that bus.
If within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> the: inverter is not restored the plant must be in at least hot standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
This configuration has been discussed at length with various NRC staff members from both the region and headquarters.
A meeting was Leld-at Region 1 Headquarters on March 14, 1990.
During this meeting, the safety significance of operating a vital bus on -bypass' was discussed at length and concluded that there was no safety -impact for operating a single vital bus on bypass for extended periods of time.
We also discussed the need for the proposed change
'to-permit adequate time for maintenance to be performed to improve inverter reliability.
our letter dated Feb.
7, 1990 addressed the no significant hazards-considerations - in accordance with 10CFR50.92.
The proposed' amendment does not affect a
change in the types or amounts of effluents that may be released offsite or result in an increase in individual.
or cumulative occupational radiation exposure.
Accordingly, the proposed change meets the criterion for categorical exclusion set forth in 10CFR51. 22 (c) (9).
Therefore, pursuant to 10CFR51.22(b), an environmental assessment is not required.
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9003280184 900319
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Be$v0r Vallcy Pow;r StStirn, Unit N3. 1 t
Docket No. 50-334, License No. DPR-66 Operating License Change Request No. 178/39 Page 2 The referenced amendment request would revise the applicable LCO to be consistent with revision 4
of the Standard Technical Specifications (STS) in the area of A.C. Vital Bus operability.
This STS Action Statement recognizes that the vital bus may be inoperable (iet not powered from it's associated inverter) for a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before the plant must initiate actions to be in hot standby.
Therefore, the purpose of this request is to permit Beaver Valley to operate beyond the existing action statement of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to a maximum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before action must be initiated to place the unit in a mode in which the applicable LCO does not apply.
Approval of this request will permit additional time to troubleshoot, repair, test, and restore the vital bus to an operable status and potentially avoid an unnecessary shutdown.
As discussed with the NRC, our current 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> action statement is more restrictive than the allowable outage time permitted by the Standard Technical Specifications.
The power supply for the vital bus is derived from one of three sources.
This is described in Section 8 of the Final Safety Analysis Report.
Normal power is supplied one of two wayst Normal system arrangement consists of power supplied from the 480 volt emergency unit substations through a rectifier, static switch and a vital bus inverter (with the DC battery floating)
The alternate system arrangement consists of power from the 480 volt emergency bus substation through a 480/120 volt line voltage regulator (re'ferred to as maintenance by-pass since it bypasses the rectifier and inverter).
These two sources of power are equivalent.
The backup emergency l
power supply for the vital busses is from the 125 volt D.C. batteries through the inverter referenced above.
Each vital bus is backed up by a battery (ie:
four vital buses, four batteries).
On the basis that the alternate system arrangement is equivalent, l
except for a ten second interruption during a loss of offsite power, we conclude that the plant can safely continue to operate for an additional sixteen (16) hours while repair efforts to restore the backup emergency power supply continue.
t We will follow the Standard Technical Specifications for determining action requirements when the inverters are not providing l
power to a
vital bus.
This is the proposed compensatory measure to be followed until a
revision to the Technical Specifications is approved by the NRC.
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Bea'vCr V311cy Pow r Stcticn, Unit N3. 1 Docket No. 50-334, License No. DPR-66 i
I operating License Change Request No.178/39 Page 3 I
As stated above, the change from 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is supported by current NRC practices.
However, the NRC proposed resolution of l
Generic Issue 48, "LCO for Class 1E Vital Instrument Buses in Operating Reactors" contains proposals which we believe would support a
longer action time than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This issue is also being reviewed i
as part of the Westinghouse Owners Group MERITS program.
i The need for prompt action on this waiver of compliance has been
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established because of continued reliability problems associated with the Unit 1
- 3 Inverter.
These issues were discussed during a i
conference call between K. D. Grada of Duquesne Light with Region 1 i
and NRR personnel on March 17, 1990.
Interim approval of the waiver I
of compliance was granted during this conference call.
l Please call me or members of my staff if you have any questions' regarding this request.
Sincerely, d k/
(VicePresident D. Sieber Nuclear Group i
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I cc:
Mr. J.
Beall, Sr. Resident Inspector Mr. W. T. Russell, NRC Region I Administrator l
Mr. P. Tam, Sr. Project Manager Mr. R. Saunders (VEPCO)
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