ML20136H412
| ML20136H412 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/15/1985 |
| From: | BALTIMORE GAS & ELECTRIC CO. |
| To: | Jaffe D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8511250101 | |
| Download: ML20136H412 (3) | |
Text
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b BALTIMORE G AS AND ELECTRIC COMPANY P.O. BO X 14 7 5 B A LTIMOR E. M A R YL AN D 212o3 VERT CL FFS N CLE R WER PLANT LUSSY MARYLAND 20657 November 15,1985
' U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 ATTENTION:
Mr. D. H. Jaffe, Project Manager Operating Reactors Branch #3 Division of Licensing
SUBJECT:
Calvert Cliffs Nuc! car Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Request for Amendment Supplement Information
REFERENCES:
(a)
BG&E letter from Mr. A. E. Lundvall, Jr. to Mr. J. R. Miller, NRC dated December 22,1983 (b)
BG&E letter from Mr. A. E. Lundvall, Jr. to Mr. J. R. Miller, NRC dated March 26,1984 (c)
NRC letter from R.
W.
Reid to A. E. Lundvall, Jr. dated February 25,1980 l
Gentlemen:
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In references (a) and (b), Baltimore Gas and Electric Company requested amendments for Units 1 and 2, respectively, which would permit the use of the existing hydrogen purge exhaust line as a containment venting system during normal operations. Reference (c) established NRC review criteria regarding electrical override / bypass for containment isolation valves. This letter is in response to your recent request that we evaluate our proposed containment vent path against these criteria.
The criteria listed in reference (c) are presented below with a description of how our system meets each criteria. The discussion pertains to MOV-6900 and MOV-6901, the hydrogen purge containment isolation valves.
C The overriding of one type of safety actuation signal (e.g., radiation) should not cause the blocking of any other type of safety actuation signal (e.g., pressure) to the isolation valves.
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Mr. D. H. Jaffe November 15,1985 Page 2 r
The signals that will actuate isolation will be CRS and SIAS. A handswitch will be installed in the control room for each valve to allow overriding CRS for the purpose of opening the isolation valves for post accident hydrogen venting.
These handwitches override only CRS to their associated valve. They do not affect the SIAS to the valves or the CRS to any other component. SIAS cannot
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be overridden. Once a SIAS has occurred, the SIAS to all plant components would have to be either reset or blocked in order to open the valves in question.
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C Sufficient Physical Features (e.g., key lock switches) should be provided to c
. facilitate adequate administrative controls.
The handswitches for both containment isolation valves as well as their respective CRS override handswitches are key operated. The keys are under administrative control.
e C The system-level annunciation of the overridden status should be provided for every safety system impacted when an override is active.
The CRS override handswitch is annunciated in the control room when the switch is placed in the override position.
C4 ~ ' At least two diverse' signals should be provided to initiate isolation of the i
containment ventilation system. Specifically, containment high radiation, safety i
injection actuation and/or containment high pressurr should automatically initiate containment isolation.
SIAS and CRS are the signals that initiate isolation. SIAS is actuated by either a high containment pressure or low pressurizer pressure. CRS is actuated by high area radiation'in the containment.-
i C The instrumentation and control systems provided to initiate containment isolation should be designed and qualified as safety-grade equipment.
The control system will be installed safety-grade.
C The overriding or resetting of the isolation actuation signal should not cause the automatic reopening any isolation / purge valve.
As explained under C-1 above, only CRS can be overridden. Overriding of CRS does not in itself cause valve motion, but only permits the valve to be opened by turning the valve handswitch to open. To prevent reopening of the valves when l
either SIAS or CRS is reset, the valves will be added to the existing control room i
reset circuitry to ensure that placing the handswitches for MOV-6900 and 6901 to the CLOSE position is a prerequisite for resetting either isolation signal.
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Mr. D. H. Jaffe November 15,1985 Page 3 t
if you should have any further questions regarding our submittal, please do not hesitate to call us.
truly yours, r
A l
General Supervisor-Training and Technical Services RED /RMS/sjb cc:
D. A. Brune, Esquire G. F. Trowbridge, Esquire t
T. Foley, NRC T. Magette, DNR t
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