ML20041A814
| ML20041A814 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 02/18/1982 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20041A815 | List: |
| References | |
| NUDOCS 8202220547 | |
| Download: ML20041A814 (2) | |
Text
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BALTIMORE GAS AND ELECTRIC CHARLES CENTER P.O. BOX 1475 BALTIMORE, MARYLAND 21203 ARTHUR E. LUNDVALL. JR Februar{l& '089 vice Patscor cn supper Q?,
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Office of Nuclear Reactor Regulation y% 4) y U.S. Nuclear Regulatory Commission Y
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Attention:
Atr. Robert A. Clark, Chief c>
Opemling Reactors Bmnch #3 4
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Division of Operating Reactors A
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Subject:
Calvert Cliffs Nuclear Power Plant Units Nos. l & 2, Dockets Nos. 50-3l7 & 50-3l8 Fire Protection Modifications
References:
(a) BG&E Letter of 11/6/8l from Lundwll to Clark of NRC (b) BG&E Letter of 3/l9/8l from Lundvall to Eisenhut of NRC (c) NRC Letter of 6/30/8l from Denton to Lundwll of BG&E (d) BG&E Letter of l/15/82 from Lundwll to Clark of NRC (e) BG&E Letter of 1/29/82 from Lundwll to Eisenhut of NRC Gentlemen:
Enclosed is the report of the independent labomtory tests of fire barrier doorway protective devices and a listing of those doorways in Unit No. I fire barriers which are to be protected by water curtains (i.e., dedicated sprinklers). Thess documents are furnished to resolve the "open" item regarding use of water curtains, Reference (a) and (b) above the exemption for suspending time requirements (Or testing, and Staff review of water curtain protection, Reference (c).
The report entitled " Fire Ewluation of Doors and a Water Curtain", Project No. 01-6763-201, dated February 1982, prepared by Southwest Research Institute documents the results of full scale fire tests performed in accordance with ASTM E-l52 procedures. These test results support BG&E's position that bulletproof and watertight door assemblies as installed at Calvert Cliffs Nuclear Power Plant are suitable for application in one and three hour fire barriers required for separation of redundant safe shutdown cables, comoonents, and systems. Similarly, two dedicated sprinklers, installed one on each side of doorways in accordance with the tested configuration, will provide an acceptable alternative to labeled f tre doors, bulletproof doors or watertight bulkhead OL doors when used at Calvert Cliffs Nuclear Power Plant.
s 8202220547 820218
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Mr. Robert A. Clark February 18,1982 The attached listing delineates where water curtains are to be utilized to meet NRC Appendix "R", Section lilG separation criteria for alternate safe shutdown.
The listed fire barriers are required to sepamte redundant safe shutdown cables, components, and systems identified in the previously submitted Intemctive Cable
' Analysis for Unit I (only), Reference (e) above. The following comments are offered for clarification and to put into perspective the use of water curtains in lieu of other types of doorway protectives:
1.
Th9 Southwest Research Institute test of dedicated sprinklers at doorways demonstrated that only one sprinkler head was required for effective three hour fire resistance. Two dedicated sprinklers are pmvided at doorways, and as indicated, in most cases, they are supplied fmm independent sprinklers systems.
The identifley "TUs) added to each area. This is provided to make a 2.
Conservative Fire Load" includes a large transient fire load (32 x l0 B comparison to the ASTM E-Il9 Time-Tempemture Curve used for structumi fire tests. Most area fire loads are chamcteristicallylow, the equivalent of 15 minutes or less. In actuality, tmnstent combustibles are controlled by Administrative Procedures so that excessive quantities cannot be introduced to shutdown rooms.
3.
Doorways are nominally 3'-0" x 7'-0" while the size of access hatch openings are identified under " Remarks". Most of the doorways and access openings listed are equipped with some form of closure. The balance are required to be unobstructed for ventilation purposes. The use of water curtains prevents loss of ventilation during normal and emergency plant operation due to accidental door closure.
4.
System opembility of water curtains is assured by sprinkler system alarm supervision. The same type release mechanisms as used on doors (i.e., fusible links)are utilized to actuate water curtains. Technical Specifications require continuous fire watches when sprinkler systems are out-of-service, which further assures continuity of protection.
5.
All rooms are provided with early waming automatic fire detection.
As indicated in Reference (d), which served to prcvide a progress report relative to the use of water curtains, the submittal of the Southwest Research Institute report completes our commitment relative to SER Item 3.l.20 and Appendix "R", Section lilG separation criteria for allemate safe shutdown.
Very truly yours, o
f.
edh.
3 cc:
J. A. Biddison, Esquire G. F. Tmwbridge, Esquire D. K. Jaffe - NRC
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