ML20212K023
| ML20212K023 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 12/15/1986 |
| From: | Ainger K COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 2520K, NUDOCS 8701280435 | |
| Download: ML20212K023 (2) | |
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. One Fret Nabonal Plaza. Chcago, luinois 7";
f Address Reply to: Post Omco Box 767 k/ Chcago.18inois 60000 0767 December 15, 1986 Mr. James G. Keppler Regional Adainistrator U.S. Nuclear Regulatory Conunission Region III 799 Roosevelt Road Glen Ellyn, IL. 60137
Subject:
Byron Station Units 1 and 2 I&E Inspection Report Nos. 50-454/86-040 and 50-455/86-040 NRC Docket Nos. 50-454 and 50-455
References:
(a) November 18, 1986 letter from C.E. Norelius to Cordell Reed i
(b) November 25, 1986 letter from C.E. Norelius to Cordell Reed 4
Dear Mr. Keppler:
References (a) and (b) provided the results of inspections at Byron Station from October 1 to October 31, 1986. During these inspections, a concern was identified regarding the potential loss of recirculation capability for both auxiliary feedwater pumps. Attachment A of this let.ter contains Conunonwealth Edison's response to the NRC concern described above.
Please direct any questions regarding this matter to this office.
l l
Very truly yours, K. A. Ainger l
Nuclear Licensing Administrator
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I ATTACHMENT A 4
1 The inspection reports included with references (a) and (b) discussed a postulated scenario which could potentially lead to loss of recirculation capability for both auxiliary feedwater (AFW) pumps. The postulated scenario involves an automatie initiation of the AFW system coincident with a seismic event. The seismic event causes the loss of the condensate storage tank. A single active failure of the AF024 valve in the closed position isolates the recirculation capability of both AFW pumps back to the essential service water i
system. When operators throttle AFW flow to control steam generator level during this scenario, a question was raised whether sufficient flow would be provided to cool the pumps.
During preoperational testing on Byron Unit 1, a minimum recirculation flow of 85 spm was obtained and found acceptable by Sargent &
Lundy. The value of 85 spm is also listed in the Byron Technical Specifications for the surveillance on these pumps. Consequently, 85 spm has I
been determined to be sufficient flow to cool the pumps.
To assure this flow is provided, Byron Station will place permanently affixed labeling at the AFW flow control stations on main control board panels IPM06J and 2PM06J and each unit's remote shutdown panel. These labels will alert the operators of the minimum flow requirements for the AFW pumps and direct them to verify minimum recirculation flow before reducing pump discharge flow below this limit. These labels will be affixed to the panels prior to Unit 2 entering Mode 3.
Prior to Unit 2 entering Mode 3, operators on shift will be trained regarding the purpose of the new labels.
i Another item in the inspection reports concerned the loss of i
recirculation capability for both AFW pumps from the fire induced failure of the AF024 valve. This postulated scenario involves a fire in the B AFW pump room which causes the loss of the B AFW pump and the AF024 valve. The AF024 valve is assumed to remain closed, but valve AF022A functions normally. We assume the AF022A valve is presumed to function normally because it is located in a separate fire zone from the B AFW pump, 3
i The AF022A valve provides a recirculation flow path for the A AFW pump to the condensate storage tank (CST). Although the CST is not Josigned l
to withstand a tornado or seismic event, NRC rules do not require desigr against a fire and concurrent tornado or seismic event. Therefore, the CGT will be available to provide a recirculation flow path for the A AFW pump. As j
a result, the failure of the AF024 valve in this scenario does not cause loss of recirculation capability for both AFW pumps.
The last item in the inspection reports concerning the AF024 valve is whether this valve should be included in the ASME Section XI Inservice Testing (IST) Program for Valves. This question is being addressed through NRR's review of the latest revision of the Byron IST Program for Valves.
If it is determined through this review that the AF024 valve should be included in the program, the program will be appropriately revised.
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