NRC-90-0060, Responds to 900104 Request for Supplemental Station Blackout Submittal
| ML20042D747 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 03/29/1990 |
| From: | Sylvia B DETROIT EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| CON-NRC-90-0060, CON-NRC-90-60 NUDOCS 9004050299 | |
| Download: ML20042D747 (3) | |
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March 29, 1990 NRC-90-0060 1
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U. S. Nuclear Regulatory Commission l
Attn Document Control Desk i
Washington, D. C.
20555 i
References:
1)
Fermi 2 j
NRC Docket No. 50-341 i
NRC License No. NPF-43 2)
Detroit Edison Station Blackout Submittal to NRC NRC-89-006), dated April 17, 1989 3)
NUMARC Letter " Station Blackout (590) Implementation:
I Request for Supplemental $80 Fubmittal to NRC" dated January 4, 1990 1
Subject:
Detroit Edison Response to Request for Supplemental SB0 Submittal to NRC Detroit Edison has performed a review of its station blackout submittal (Reference 2) as requested by WUNARC (Reference 3). The results of our t
J review are addressed in this letter. The review was performed to address NRC concerns with proper documentation and consistent implementation of l
NUMARC 87-00 guidance. We also reviewed our previous station blackout l
submittal in light of the clarification provided by WUNARC in their January l
1 4, 1990 letter (Reference 3). Where appropriate, we have addressed these clarification items in this submittal, j
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f Our review affirms that the previous Detroit Edison station blackout submittal (Reference 2) was based on use of NUMARC 87-00 guidance. The i
applicable NUMARC 87-00 assumptions are documented and are on file. Where there have been departures from NUMARC 87-00 methodology, they have been documented and are discussed in this submittal, j
The review of the station blackout submittal affirms that no hardware changes to the plant will be required to meet the station blackout rule.
j In its station blackout submittal Detroit Edison committed to perform a battery capacity test of the Non-Class IE BOP-2PC 260/130 volt battery.
The battery capacity test was completed during the first refueling outage i
and the BOP battery performed satisfactorily. The required battery capacity to support station blackout operation is 100% of nominal.
Therefore, battery replacement is not necessary.
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USNRC March 29, 1990 l
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Procedure revisions needed to meet NUMARC 87-00 will be completed by April l
j 14, 1990, as per the original submittal.
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An EDO Reliability Program similar to that required by NUMARC 87-00 has been in place for some time at Fermi 2.
EDG st, arts and failures are tracked by procedure, and the target 0.95 availability has consistently been exceeded. Note that the Fermi 2 Technical Specifications require a
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l similar tracking program.
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j NUMARC 87-00 assumes that the control room does not exceed 120 F during a 0
station blackout and that the primary containment temperature during the j
event is enveloped by LOCA profiles. Detroit Edison has verified NUMARC's l
0 assumption that the Fermi 2 control room would not exceed 120 F during a J
postulated blackout event. Because Ferai 2's control room has a variety of i
construction materials that must be considered, a unique compart.nent heat up analysis was performed that. takes credit for other types of wall I
materials (plaster, block walls, etc.) and takes credit for the volume above t.he partial suspended ceiling within the control room. This analysis is documented in a design calculation on file at Fermi.
Detroit Edison also performed a plant specific heat up analysis of the primary containment. The analysis does not assume reactor depressurization l
and uses the drywell atmosphere, cont.ainment steel liner and sacrificial j
shield steel liner as heat sinks. The analysis was redone to account for an assumed 25 spa seal leakage from the reactor recirculation pumps. This i
is a conservative assumption because 25 spa is the total react.or coolant j
system leakage when averaged over any 24-hour period that is allowed by the plant Technical Specifications. The analysis is documented in a design calculation and concludes that the cont.ainment design temperature of 0
340 F is not exceeded within the first hour of station blackout,. The i
drywell temperatures given in Det.roit Edison's initial st.ation blackout j
submittal have been revised to include the assumption of reactor i
I recirculation pump seal leakage.
Detroit Edison's original response regarding compressed air usage remains unchanged. However, the statement t. hat no air-operated valves are relied upon to cope with a station blackout for one hour needs to be clarified.
i As noted in the response, the two low-low set relief valves and five ADS i
safety relief valves rely on nitrogen to operate and each valve has an t
accumulator sized to provide five actuations each. These valves will be available and are relied upon to cope with a station blackout.
A final clarification regarding cont.ainment isolation from the original station blackout submittal is appropriate. Valve position verification I
will be determined by visual observation of valve stem position at the i
valve location or by control panel indicating lights as available.
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USNRC Harch 29, 190 NRC-90-0050 Page 3 If there are any quest,1ons regarding this submittal, please contact Mr.
Lewis Bregni at (313) 586-4072.
Sincerely, h'fctt A'
cc:
A. B. Davis R. W. DeFayette W. G. Rogers J. F. Stang n
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