ML19250C322
| ML19250C322 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/09/1979 |
| From: | Reid R Office of Nuclear Reactor Regulation |
| To: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7911230212 | |
| Download: ML19250C322 (5) | |
Text
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,(pa aro k UNITED STATES uq e(
g NUCLEAR REGULATORY COMMISSION
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j WASHINGTON, D. C. 20555
%g' N 4 November 9,1979 j
Dockets Nos. 50-317/318 Mr. A. E. Lundvall, Jr.
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Vice President - Supply Baltimore Gas & Electric Company P. O. Box 1475 Baltimore, MD 21203
Dear Mr. Lundvall:
By letter dated September 14, 1979, you submitted a procedura entitled,
" Test to Qualify Cable and Pipe Penetrations in Fire Walls and Floors for Calvert Cliffs Nuclear Power Plant" for our review and requested written notification of our acceptance of this procedure.
We approve the procedure subject to a satisfactory resolution of the enclosed comments. These comments were previously sent to your staff by telecopy on November 5, 1979.
A meeting has been scheduled, to discuss our comments, for November 14, 1979 at 9:30 a.m. in Bethesda, Maryland.
Your staff has agreed to:
(1) give the staff adequate notice of the testing schedule to allow staff observations of the procedure; and (2) submit a report documenting the testing results in a timely manner after completion of the testing.
Sincerely,
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Ibf. (
a Robert W. Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors
Enclosure:
Coninents on Test Procedures cc w/ enclosure:
See next page
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3 Baltimore Gas & E' ectric Company cc:
Janes A. Biddison, Jr, Mr. R. M. Douglass, Kanager General Counsel Quality Assurance Department G and E Building Room 923 Gas & Electric Building Charles Center P. O. Box 1475 Baltimore, Maryland 21203 Baltimore, Maryland 21203 George F. Trowbr+ ige, Esquire Shaw, Pittnan, F tts and Trowbridge 1800 M Street, H.U.
Washington, D. C.
20036 11r. R. C. '. Olson II is Baltimore Gas and Electric Company Room 922 - G and E Building Post Office Box 1475 Baltimore, Maryland 21203 fir. Leon B. Russell, Chief Engineer Calvert Cliffs Huclear Power Plant Baltinore Gas and Electric Company Lusoy, Itaryl and 20657 i
Bechtel Power Corporation ATTH:
f tr. J. C. Judd Chief Nuclear Engineer 15740 Shady Grove Road Gaithersburg, Maryland 20760 Combustion Engineering, Inc.
ATTH:
ifr. P. W. Kruse,flanager Engineering Services Post Office Box 500 Windsor, Connecticut 06095 Calvert County Library Prince Frederick, Maryland 20678 1388
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ENCLOSURE CALVERT CLIFFS NUCLEAR POWER PLANT DOCKET NOS. 50-317, 50-318 C0]!MENTS ON TEST PROCEDURES 0
1.
It ropears that the results of one or two tests will be applied th Jughout tne plant; therefore, each of the test variables should reflect the nost conservative condition among all plant areas.
The following considerations as pro osed in the licensee's procedure did not ap ear to be conservative:
A) Tray Fill (C-5)*
Cable loading of 50% in trays was proposed while in many plant areas tray fill in excess of 100% was observed.
Verify that the 50% cable tray load is conservative.
B) _Tyce of Cables (C-5)
Silicone ru.bber insulated, glass braid covered, and asbestos braid jacketed cables were proposed for the test to qualify the electrical penetration seal while the plant is known to have many non-silicone rubber cables (see Section 4.8 of MRC's Fire Protection SER).
By the licensee's previous test results, silicone rubber cables were shown to have a better fire retardant characteristics than conventional electrical cables; test results qualifying silicone rubber cable penetrations, therefore, will not be applicable to non-silicone rucber cable penetrations.
The licensee is requested to include a provision in the test wnich will cuaiify
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non-silicone rubber cable penetrations.
C)
Slab Thickness (Fig. 1)
A minimum of 2 feet thick wall or floor was proposed as the test assembly. We request the licensee to verify that there is not a wall or a floor in the plant that is less than 2 feet thick and is penetrated by electrical cables.
D) Test Conficuration (cover letter)
It was proposed that the penetration assembly will be tested in the horizontal or floor configuration to cuality both wall and floor fire stop design. We agree that floor configuration is more conservative; however, the wall and the floor penetrations in Calvert Cliffs have different designs.
The licensee is requested to include some wall penetration design (without Vermiculite void fill) in the horizontal configuration to quality the wall penetrations.
The number noted in the parentheses refer to the section in the licensee's procedure.
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E) Picina Penetrations (C-8)
It.vas indicated that the pipe penetration will utilize 6" diameter pipe and 10" diameter sleeve. We recuest the licensee to verify: (i) if all piping penetrations have sleeves; and (ii) if 6" pipe and 10" sleeve corresponds to the norst configuration in the plant. A larger sleeve 2nd/or a smaller pipe is believed to represent a worse configuration.
2.
The test procedure did not specify the pressure :ifferential to be maintained across the penetrations.
Verify nat a positive pressure differential will be maintained to sirulate a fire si tuation.
3.
Conduit Assembly A) The off-gassina of cables inside conduits may induce a fire in the terninal switch box outside the fire area which has an ignition _ source. A provision should be included in the test to demonstrate that the off-gassing of cables in the conduit will not cause a fire in the terminal switch box.
- 5) Testing the conduit.of cnly two feet unrealistic and non-conservative because it does not simulate differential expansions, off-gassing and changes in conductor and insulation resistance; we recor=end a configuration similar to that shown below be tested.
Sharp turns should be included.
Verify that the new length and configuration provide a realistic simulation
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of the plant conduit configuration.
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Test Duration (E-3)
Since some ci. oles required for the long term cooling ray be required to # unction up to 30 days following the fire, the test should demerctrate that the function of electric circuits can be maintained not cnly before, during and right after the fire, but also a reastnable period of time thereafter, exposirg the cables and tne conduit to an atmosphere similar to that following a fire.
5.
The test should include certain provisions to demcnstrate that techanical disturbances, (e.g., impact) cenerally expected in fire fighting and other possible activities subs-cuent to the fire, on the conduit will not disable the funct on of the cables.
6.
Mcse Stream Test (D-2) 0 The hose stream with the nozzle discharge angle of 30 is proposed for the hose stream test.
This stream while it is acceptable to the area equipped with a spray nozzle, may not be conservative in the areas where spr y nozzles are not provided.
Specifically, it is unlikciy.that sfray nozzles are provided for al.1 areas where pipe penetrations e.~ist.
Testing the piping pent tration with the proposed hose stream, therefora, is not conserva"ive.
Straight stream should be used to qualify penetrations cated in areas protected by noses equipped with the regular nozzle.
7.
Provide an analysis which verifies that changes in conductor and insulation resistance during a fire will not cause circuit mal functions.
8.
Describe the post test inspections and criteria to be used to determine that the cable is still functional and the length of the cable can be expected to remain functional.
Provide a brief description of the procedure to be used to replace the damaged cable following a fire.
9.
The circuit integrity test should include a provision to verify that switching transients will not have an adverse effect in naintaining the electrical function of the cable.
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