ML20206C920
| ML20206C920 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 04/02/1987 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.078, RTR-REGGD-1.078 2930K, NUDOCS 8704130192 | |
| Download: ML20206C920 (2) | |
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~ One First National Plaza, Chcago, Hlinois q' Address Re#y to: Post Omco Box 767
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Checa00. lilinois 60800 - 0767 April 2, 1987 Mr.~ Harold R. Denton U.S. Nuclear Regulatory Commission Office of' Nuclear Reactor Regulation Washington, DC. 20555 e
Subject:
Braidwood Station Units 1 and 2 Removal of Control Room Chlorine Monitors NRC Docket Nos. 50-456/50-457
Reference:
(a)
June 3, 1986 A.D. Miosi letter to H.R. Denton (b)
December 23, 1986 S.C. Hunsader letter to
^
H.R. Denton (c)
March 4, 1987 S.A. Varga letter to D.L. Farrar 2
Dear Mr. Denton:
References (a) and (b) provided Commonwealth Edison's justification for the removal of the chlorine monitors from the i
control room ventilation system at Braidwood Station.
Reference (c) provided the NRC approval to remove the chlorine monitors pending a commitment by Commonwealth Edison to perform additional Technical Specification surveillances.
This letter provides Commonwealth Edisons' commitments regarding this matter.
4 The chlorine monitors will be removed from the control room ventilation' system design prior to initial reactor criticality of Braidwood Unit 1.
Manual isolation capability of the control room envelope will be provided and this capability will be subsequently demonstrated on an 18 month basis, thereafter, via Technical Specification surveillance.
t Regulatory Guide 1.78, position 5(b), describes the analysis required for a maximum concentration-duration accident.
It 4
requires that the continuous release of hazardous chemical from the largest safety relief valve on a stationary, mobile, or onsite source falling within the guidelines of Table C-2 be considered.
i Using the interpolation method provided in Appendix A of Regulatory Guide 1.78 for chlorine in conjunction with Table C-2, a
control room habitability evaluation would not be required when the air exchange rate is 0.39 per hour.
This is based on a toxicity limit'of 45 mg/m3 being present in quantities less than 83 tons (the maximum cargo weight in the railroad tank car) at a location j
between four and five miles away from the control room.
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'8704130192 870402 i
PDR ADOCK 05000456
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> I For the Braidwood control room volume of 405,164 cubic feet, a maximum in leakage of 2633 cubic feet per minute (CFM) is required to maintain an air exchange rate of 0.39 per hour.
Due to the level of integrity designed into the Braidwood control room envelope, we are confident that the infiltration test will yield results much smaller that 2633 CFM and that further habitability analysis and subsequent inleakage testing will not be necessary.
A test will be performed to determine infiltration into the control room envelope when the control room is in the isolation mode.
To ensure plant design conditions are accurately represented, this test will be performed after Unit 2 construction activities and final preoperational testing of the Auxiliary Building Ventilation System are completed, currently scheduled to be completed prior to Unit 2 fuel load.
Since bubble tight dampers have been installed as part of the control room boundary, the measured infiltration is expected to be relatively small.
NRC review and acceptance of these commitments is requested.
Please address any questions concerning this matter to this office.
(
ed" S.
C. Hunsader Nuclear Licensing Administrator
/klj cc:
J.
Stevens Resident Inspector 2930K J