ML19309B025
| ML19309B025 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/19/1978 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8004020502 | |
| Download: ML19309B025 (4) | |
Text
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,,a, Oh REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
DISTRIBUTION FOR INCOMING MATERIAL 50-312 REC: REID R W ORG: MATTIMOE J J DOCDATE: 06/19/78 NRC SACRAMENTO MUN UTIL DIST DATE RCVD: 06/22/79 DOCTYPE: LETTER NOTARIZED: NO COPIES RECEIVED SUDJECT:
LTR 1 ENCL 0 FURNISHINO ANSWERS TO QUESTIONS THAT NRC STAFF HAD CONCERNING APPLICANT"S QUALIFICATION FIRE STOP TEST.
PLANT NAME: RANCHO SECO (SMUD)
REVIEWER INITIAL:
XJM DISTRIBUTOR INITIAL-)L-
- DISTRIBUTION OF THIS MATERIAL IS AS FOLLOWS ******************
FIRE PROTECTION INFORMATION (AFTER ISSUANCE OF OL).
(DISTRIBUTION CODE AGO6)
FOR ACTION:
BR CH :_ ' ORE #4 BC**LTR ONLY (3 )
INTERNAL:
H'LTR ONLY(1 )
NRC PDR**LTR ONLY(1)
. a E+-*LTR ONLY ( 2 )
OELD**LTR ONLY(1)
AUXILIARY SYS BR**LTR ONLY(2)
AD FOR SYS & PROJ**LTR ONLY(1)
PLANT SYSTEMS DR**LTR ONLY(5)
WAMBACH**LTR ONI.Y( 1)
R.
MURANKA**LTR ONLY(1)
HANAUER**LTR ONLY(1)
EXTERNAL:
LPDR'S SACRAMENTO, CA**LTR ONLY(1)
REGION V**LTR ONLY(1)
TIC **LTR ONLY(1)
NCIC**LTR ONLY(1)
ACRS CAT B**LTR ONLY(16)
W ISTRIDUTION:
LTI 39 ENCL O CONTROL NBR:
74
._7-SIZE: OP 6
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TsE ENo 8 0 04 0 20 d5iD 3?
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f f.v; \\ " v ~ ~ c r - h y g g sACHAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S street. Box 15830, Sacramento, Califomia 95813; (916) 452-3211 June 19,1978 Director of Nuclear Reactor Regulation Attention:
Mr. Robert W. Reid, Chief Operating Reactors, Sranch No. 4 U. S. Nuclear Regulatory Comission Washington, D. C.
20555
~
Docket No. 50-312 Rancho Seco Nuclear Generating Station, Unit No. 1
Dear Mr. Reid:
Listed below are the answers to questions that NRC staff had concerning the District's Rancho Seco Qualification Fire Stop Test:
1.
Question What was the output of the burners for the cable tray crossing fire stcp tests?
Answer In the horizontal cable tray crossing fire stop tests and the horizontal-vertical cable tray crossing. fire stop tests, the burner output was 177,500 BTV's per hour per burner.
Therefore, the combined heat output of the two burners used in the tests was 355,000 BTV's per hour.
In the vertical cable tray crossing fire stop tests, the gas burners were operated at 30, 50 and 55 psi.
The heat output at these pressures is as follows:
Pressure BTU's Per Hour Per Burner 30 215.000 50 311,500 55 335,500 The vertical cable tray crossing fire stop tests were performed with a pressure initially of 50 psi, therefore for the initial portion of the test, which utilized two burners, the total heat output was 623,000 BTU's per hour.
2.
Question The horizontal-vertical cable tray crossing fire stop test demonstrates protection provided the horizontal tray from a fire in the vertical tray.
However, it does not demonstrate protection for the vertical tray from a fire in the horizontal tray.
In placing these barriers, credit should not be taken for the barrier preventing a fire in the horizontal tray from affecting cables in the vertical h#g tray.
.S,o m-
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Robert W. Reid June 19,1978 i
2.
Answer In u:,ing the horizontal-vertical cable tray crossing fiic stop, the District will not take any credit for the berier preventing a fire in a horizontal tray from affecting cables in the vertical tray.
The stop was specifically designed and will be used to prevent a fire in a vertical tray from spreading to an adh..ent horizontal tray.
3a. Question What is the maximum pressure differential that a fire stop would be expected to experience in the plant?
Answer Except for the A diesel generator room, Fire Area 37, the maximum differential a fire stop will see is antici-pated to be 0.12 inches of water.
The minimum differential maintained across the fire stop during the tests was 0.25 l
inches of water. The maximum differential a fire stop in i
the A diesel generator room will experience is approximately
)
0.5 inches of water.
For this room the District proposes to erect a fire stop using a solid core of Dow Corning silicone foam which will provide an airtight stop and be capable of withstanding-0.5 inches of water differential.
Details of the design and support documentation for the qualification of the fire stop will be submitted to the NRC at a later date.
3b. Question What is the maximum tray fill allowed or used in the plant?
Answer The nominal maximum designed fill allowed in the plant is 40%, however, there are a few trays in the plant which exceed this.
The maximum calculated fill for a tray is 90% and this particular tray does not go through a fire stop.
It is located beneath the control room floor.
There are many cables that enter the tray from each end and exit from the tray going up through floor slots on the control room floor.
These cables therefore do not go from one end of the tray to the other.
With this particular tray, if a cross section was taken at any point in the tray the actual l
fill would be much less in value than 90% since that value is based on the. assumption the cables are being routed from one end of the tray to the other.
Listed below in 3%
steps are the number of trays contained in the plant that exceed the nominal design value of 40%.
Percent Fill Number of Trays 41 - 43 43 44 - 46 28 47 - 49 14 l
50 - 52 9
53 - 55 5
l 56 - 58 5
l 59 - 61 2
90 1
l
I.
]
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.J Robert W. Reid June 19,1978 There are approximately 2,300 trays in the plant. There-fore, the percentage of trays with a fill greater than 40% is.approximately 5%.
3c.
Question Did flaming occur on the unexposed side of the fire stop
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during the cable tray wall penetration fire stop test?
Answer -
There was nt, flaming on the unexposed side of the fire stop during tne test.
Sincerely yours,
. hhb
' J! J. Mattimoe Assistant General Manager and Chief Engineer
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