ML20236M715
| ML20236M715 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 10/23/1987 |
| From: | Gucwa L GEORGIA POWER CO. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML20236M524 | List: |
| References | |
| SL-3503, TAC-67844, NUDOCS 8711130254 | |
| Download: ML20236M715 (3) | |
Text
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9, f33 ENCLOSURE 2
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cm A
.t Attonta. Goorgia 30308 Telechone 404 526 6526 Ma,hng Address.
1 Post office Box 4545 i
Atta ta. Geo gia 30302 L
LL ( Gu ooh t.T L.T.Qucwa 1
i Ma a;er %c; ear $Pe9 and Liceas ag SL-3503 1795C X7GJ10-H000 October 23, 1987 U.S. Nuclear Regulatory Commission Regional Administrator - Region II Sulte 2900 101 Marietta Street, N. H.
Atlanta, Georgia 30323 Attn:
Dr. J. Nelson Grace PLANT HATCH - UNIT 2 NRC DOCKET 50-366 OPERATING LICENSE NPF-5 TECHNICAL SPECIFICATIONS Gentlemen:
This letter constitutes written followup of a relief request to Technical Specification requirements.
Specifically, relief from
' Technical Specification requirements (on a one time basis) was requested, and subsequently granted, via telecon between Georgia Power Company (GPC) personnel, members of your staff, and members of the NRR staff on October 22,-
1987.
The waiver applies to Plant Hatch Unit 2
Technical l
Specifications 3.6.3.a.
and 3.4.7, each of which provides a Limiting Condition for Operation for failure of Main Steam Isolation Valves to meet closure time requirements.
Plant Hatch Unit 2 is currently operating at 85% of rated power with the "C" inboard Main Steam Isolation Valve (MSIV) out.of service, closed, and isolated.
This MSIV was isolated following a measured closure time of 2.3 seconds during surveillance testing.
. Unit 2
Technical Specifications Table 3.6.3-1 and Specification 3.4.7 require that this valve close between 3
and 5
seconds.
Pursuant to Technical Specifications 3.6.3.a.2 and 3.4.7.2.,
the affected penetration was r
isolated by closure of the "C"
inboard and outboard MSIVs.
(A Plant Specific evaluation justifying operation in this mode has been performed by General Electric).
The plant is required to perform the quarterly HSIV surveillance testing on the reaaining steam lines.
In order to do this, with one steamline isolated, the operating power level would have to be reduced significantly (approximately 50% of rated thermal power).
This reduction i
would be required to prevent an inadvertent scram or isolation on high reactor pressure, high neutron flux, or high steam flow.
GPC would j
prefer to reopen the isolated MSIV, while performing the surveillance testing from power levels at or below 75% of rated, in lieu of reducing 8711130254 871029 DR ADOCK O 6
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.U.S. Nuclear Regulatory Commission
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October. 23, 1987 Page Two i
thi, reactor power -to a lower level anti risking a spurious ~ isolation or-l
- scram, o
Since GPC intends to be operating with the fast. stroking MSIV open-
. for only a short period time.(approximately three. hours are expected - to be-necessary to per7orm the. MSIV surveillance test), ;it is highly unlikely that the any unusual circumstances (e.g., loss of offsite power) would occur to initiate a' ' closure of the MSIV.
Additionally, the performance of the MSIV testing with all valves-initially open will be-far.less likely to result in an' inadvertent isolation signal due to high team flow. thanfif the testing were performed at a reduced power level s
with one MSIV isolated.
The postulated consequences ~ of an inadvertent closure of all' four I
MSIVs from 75% power, with one valve closing more rapidly than 3 seconds, have been assessed.
The two primary areas of concern are fuel thermal limits, and reactor overpressure.
In all of the events which have been evaluated.to establish the -limiting minimum critical power ratio (MCPR),
the MCPR occurs well before the time the MSIVs are signaled to close.
Consequently, th'e more rapid closure of one MSIV. will not ' impact the limiting fuel thermal margins.
The transient event utilized to evaluate reactor overpressure is the MSIV closure with flux scram event.
This-postulated event is initiated from 105%
of rated steam flow (approximately 104% of rated thermal power) by the simultaneous closure of all 'MSIVs (the minimum Technical Specification of three seconds is assumed) with a coincident failure of the MSIV position switch scram signal. The reactor scram is assumed to occur later in the event due to a hign neutron flux signal.
The Cycle 7 reload licensing evaluation resulted in a calculated peak vessel pressure of 1255 psig for this event, which is 120 psi below the ASME code limit of 1375 psig.
The initiation of this event from 75% of rated power with a faster closure.of one of the four MSIVs is expected to result in a peak vessel pressure
,which is either bounded by or very close to the value determined in the l
reload licensing evaluation.
Based upon the assessments above, it is concluded that the operation of Plant Hatch Unit 2 at power levels at and below 75% of rated with the MSIV (with a rapid closure rate) reopened during the surveillance testing of the ~ remaining MSIVs is justified given the low probability of an unexpected. occurrence and the results of the assessment or the potential consequences-of such an occurrence.
L 1795C
1 i.
Georgia Power A i
U.S. Nuclear Regulatory Comnission October 23, 1987 Page Three.
GPC intends to pursue permanent relief to the MSIV closure time limit Technical Specification limit in the near future.
If you have any questions in this regard, please contact this office at-any time.
Sincerely, 1
fn 1_
L. T. Gucwa RE8/lc
Enclosure:
c:
Georaia Power Comoany Mr. J. P. O'Reilly, Sr. Vice President - Nuclear Operations Mr. J. T. Beckham, Jr., Vice President - Plant Hatch GO-NORMS U. S. Nuclear Reaulators Commission. Washinaton. D. C.
Mr. L. P. Crocker, Licensing Project Manager - Hatch i
U. S. Nuclear Reaulaton Commission. Reaion II l
Mr. P. Holmes-Ray, Senter Resident Inspector - Hatch i
I l
l 1795C l
runs
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