ML19207A388
| ML19207A388 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 07/16/1979 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 7908170313 | |
| Download: ML19207A388 (3) | |
Text
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BALTIMORE GAS AN D ELECTRIC COMPANY GAS AN D ELECTRIC B UILDING B ALTl M O R E, M ARYLAN D 212 03 July 16, 1979 Anywun E. LUN OVALL,JR.
vice p.s s.ocr
- sum, Mr. Boyce H. Grier, Director Office of Inspection and Enforcement, Region 1 U. S. Nuclear Regulatory Co= mission 631 Park Avenue King of Prussia, PA 19h06
Subject:
Calvert Cliffs Nuclear Power Plant Units Nos. 1 & 2, Dockets Nos. 50-317 & 50-318 NRC IE Bulletin 79-01 and 01A
' Additional Information
Reference:
a) BG&E letter dated 6/13/79 from A. E. Lundvall to Director, DROl, NBC IE Bulletin No. 79-01.
b) BG&E letter dated 5/28/79 from A. E. Lundvall
'co Director, DROI, same subject.
Dear Mr. Grier:
Reference (a) submitted our initial response to IE Bulletins 79-01 and 01A.
In that response ve identified some ASCO solenoid valves which did not have the environmental qualifications required for their application (containment purge isolation valves).
In a subsequent letter, Reference (b), we supplied further infor=ation on additional ASCO valves which lacked sufficient qualification.
In discussions with yocr Staff concerning the above-mentioned letters, we vere requested to supply additional amplifying information concerning the design function of certain of the insufficiently qualified valves. The requested information is provided belov by solenoid valve identification number.
SV-2085 Containment Instrument Air Header This valve is not necessary for containment isolation; there are two isolation valves upstream. If the valve should fail either oren or shut, there vould be no adverse effect on the three valves it protects since they would all feil to their appropriate design positions on loss of air. One of the three valves is controlled by SV-517, which is discussed below. The remaining two valves are SV-518 and SV-519, both of which are qualified.
If SV-2085 was to fail open resulting in a loss of instrtment air, SV-518 and 519 vould fail cpen, their fail-safe position except in the case of a downstream 2" charging line break, which is not postulated to occur during this LOCA scenario.
d.,
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o Page 2 SV-517 Auxiliary Soray Lira This is not a containment isolation valve.
In addition, its failure to either the open or shut position vould have no adverse effect on plant safety.
If the valve failed open, it vould open up a spray path to the pressurizer from the charging pumps, which could then be shut off if pressure dropped. No credit is assumed for the charging pumps on a loss-of -coolant-accident. If th? valve failed shut, it would remove from use one of the two redundant flev paths for core flushing to prevent boron precipitation in the reactor vessel during long-term cooling following a cold leg break. The alternate flushing path would still be available for use.
57 611, 621, 631, 6hl SI Tanks llA & B and 12A & B Fill and Drain Lines These valves are not required for containment isoistion; there are t io locked-closed isolation valves downstream of them. These valves are normally closed and fail closed.
If they fail open the chance of any adverse effect is extremely small for the following reasons:
1.
On a large pipe break, the SI tanks release their contents within minutes after the accident. Therefore, the opening of the valves would have no consequence.
2.
If, by some remote chance. one did fail open before the tank's contents was released, it voald allow the tank's contents to fill up the 2" recirculation line to the Refueling Water Tank up to the containment isolation valves; this would deplete the 1000 ft.3 tank storage by apnroximately h0 ft.3 If, in addition, the drain valve (operated by SV-661, discussed belov) to the reactor coolant drain tank from the recirculation line also failed, approxi=ately 200 ft.3 of borated water vould be lost from the SI tank.
3.
After a SIAS, the instrument air compressors vill trip on hich air temperature, and subsequently SV-2085 vill act to close CV-2085, shutting off instrument air to these solenoid valves, decreasing the likelihood that they would open.
SV 618, 628, 638 & 6h8 SI Tanks 11A,113,12A & 12B Check Valve Leakace Drain to Refueline Wcter Tank (RWT)
These valves are not contain= nt isolation valves; there are two locked closed isolation valves downstream of them. These valves are normally closed, close on a SIAS, and fail closed.
If they fail open the chances of any adverse effect is extremely rmall for the following reasons:
1.
Same as Reason (1) above.
2.
If by some remote chance one did fail before the tank's contents were released, it would supply an alternate path (blocked doan-stream by isolation valves) for the tank's contents to flov once released; however, this alternate path is only a 1" line off the main 12" tank discharge line.
Consequently, an insignificant amount of water would be lost.
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Page 3 SV-661 SI Recirculation Return Line Drain to RC Drain Tank This valve is not a containment isolation vs1ve; there are two locked closed isolation valves downstream of the drain.
If this valve failed open instead of the design position (fail closed), the chances of any adverse effect is extremely snall for the following reasons:
1.
Same as Reason (1) above.
2.
If it did fail open before the tank's contents vere released, it would only have an effect if one of the SV-611 621, 631, or 6hl valves had also failed, in which case the previously blocked-up water in the recirculation line would be allowed to flov to the RC drain tank.
3.
Same as Reason (3) above.
We have placed an order for replacement ASCO Soleniod valves which are properly qualified, and we expect to receive them in time for installation during the next refueling outage for each unit.
Very truly ye s,
f. y-_
_) & '
> 1-cc:
J. A. Biddison, Esquire G. F. Trowbridge, Esquire Mr. E. L. Conner, Jr. - NRC Mr. P. W. Kruse - CE Director of Reactor Operations Inspection Office of Inspection and Enforcement Washington, D. C.
20555 705 36I