ML20129A120
| ML20129A120 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/31/1985 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0800, RTR-NUREG-800 NUDOCS 8506040472 | |
| Download: ML20129A120 (5) | |
Text
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o DUKE Powen GoMPANY P.O. box 33180 CHAMLOTrE, N.C. 28242 HALH. TUCKER Teuzenown vm.parameur (704) 373-4531 May 31, 1985 muum, -
Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
Ms. E. G. Adensam, Chief.
Licensing Branch No. 4 Re: Catawba Nuclear Station Docket Nos. 50-413 and 50-414
Dear Mr. Denton:
The fire protection program for Catawba is discussed in Section 9.5.1 of the FSAR. This program was reviewed by the NRC Staff in accordance
'with the Standard Review Plan (SRP) (NUREG-0800) as discussed in Section 9.5.1 of the Catawba SER including Supplements'2 and 3.
The Staff's review included a site audit on November 1-4, 1983.
On April 15-19, 1985, NRC/ Region II personnel conducted an on-site inspection of fire protection features including implementation of the plant safe shutdown guidance provided in position C.5.b and C.5.c of Section 9.5.1 of the SRP. The results of this inspection are detailed in Inspection Report No. 50-413/85-15.
It was noted during this inspection that the structural supporting steel which supports protected cables in the auxiliary feedwater pump room area were not fire-protected with a one-hour fire resistive
. material (UI 413/85-15-01).
It was agreed during the inspection that Duke's technical justification for not wrapping the cable tray supports would be submitted to NRR for review.
As discussed in the attached evaluation, the maximum potential fire load in the auxiliary feedwater pump room area is very low. As this evaluation demonstrates, it is not possible for sufficient heat to be developed for the duration needed to result in failure of any unprotected cable' tray supports.- Therefore. it is our conclusion that the addition of fire-resistive material to the subject cable tray supports is not necessary.
Very truly yours, h)/ $lQ Hal.B. Tucker ROS: sib Attachment j
s 8506040472 850531 PDR ADOCK 05000413 F
PDR v
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- Mr.. Harold R.,Denton, Dir:ctor-
'- May 31, 1985.
. Page Two ec: :Dr. J. Nelson Grace, Regional Administrator
.U. S. Nuclear ~ Regulatory Commission Region II.
'101.Marietta Street..NW, Suite 2900 Atlanta, Georgia. 30323 NRC Resident Inspector Catawba Nuclear Station Robert Guild, Esq.
P. O. Box 12097
' Charleston, South Carolina 29412 Palmetto Alliance-2135 Devine Street
~ Columbia, South Carolina 29205 Mr.. Jesse L. Riley Carolina: Environmental Study Group 854 Henley Place Charlotte, North Carolina 28207 A
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p April 26,1985 Memo to File Re: Catawba Nuclear Station Calculation of Unit 1 Auxiliary Feedwater Pump Room Maximum Potential Fire Severity File No: CN-1435.03 The maximum potential fire severity for a postulated fire with the Unit 1 Auxi-liary Feedwater Pump Room is calculated below. This task was performed to show that the worst case ambient ceiling temperature under fire conditions would not result in fail.ure of cable tray support members. A minimum time interval of 5 minutes with ambient ceiling temperature in excess of 1100 F is considered necessary to heat cable tray support members internally to the point of failure.
The calculations are performed considering 1!he actual fixed fire load within the room. For conservatism, a transient fire load consisting of 100 lb. of cellulose based material and 10 gallons of flamable liquid has been included.
The calculations ar e based o use of non-Jacketed annor interlocked cable with a heat of combustion of 12,800 Btu per pound of combustible cable material.
All cable trays are assumed to be 67% filled.
The following heats of combustion are assumed:
Flammable Liquid - 20,000 Btu /lb.
Lubricating Oil - 20,000 Btu /lb.
Cellulose Based Materials - 8,000 Btu /lb.
Fixed Fire Load 6" Cable Tray total length = 54 ft.
heat of combustion = 17,792 Btu /ft.
total heat of combustion = 960,768 Btu 12"' Cable Tray total length = 42 f t.
heat of combustion = 35,584 Btu /ft.
total heat of combustion = 1,494,528 Btu 24" Cable Tray total length = 193 f t.
heat of combustion = 71,168 Btu /ft.
total heat of combustion = 13,735,424 Btu Miscellaneous conduit and cable drops (1% of total-cable tray heat of combus-tion) = 161,907 Btu
P 1
Memo to File '
April 26,1985 Page 2
' Lubricating Oil 1.5 gallons in each motor driven CA pump = 3 gallons total X 10 lb./ gal. = 30 lb.
30 lb. X 20,000 Btu /lb. = 600,000 Btu
. Total Fixed Combustible Load =. E,952,627 Btu Transient Fire Load Cellulose-Based Material 100 lb. X 8,000 Btu /lb = 800,000 Btu Flansnable Liquid 10 gal. X 10 lb./ gal. = 100-lb.
.100 lb. X 20,000-Btu /lb. = 2,000,000 Btu Total Transient Combustible Load = 2,800,000 Btu
- Total Fixed and Transient-Combustible Load = 19,752,627 Btu Room Floor Area = 3,500 sq. ft.
Combustible Load = 5,644 Btu /sq. ft.
1 Interpreting from Table 5-9B on page 5-90 of the NFPA Handbook 1,334 Btu /sq.
ft. results in a severity equivalent to a fire of one minute duration. (Stan-dard Time-Temperature Curve)
Therefore, 5,644 Btu /sq. ft results in a severity equivalent to a fire of 4.23 minutes duration _.
(Standard Time-Temperature Curve)
-Proof Converting.the total heat of combustion to pounds of cellulose material
.19,752,627 Btu = 2469.08 lb*
8,000 Btu /lb.
2469.08 lb.
l3500sq.ft. =.705 lb./sq. ft.
2 ASTM E119 indicates that a 10 lb./sq. 'ft. load of combustible material will produce a fire of one hour duration.
Therefore, a combustible load of.705 lb./sq. ft. would produce a fire of 4.23 minutes in duration.
Comments While the temperature of the postulated fire may ideally rise faster than the standard time-temperature curve (1000 F at 5 minutes) due to the high heat con-
. tent of the materials, the resulting fire severity is minimal due to the lack of significant combustible loading.
Memo to File April 26, 1985 Page 3 These calculations, while not considering factors such as ventilation, load
- geometry,' distribution, and thermal characteristics of the boundaries, must be considered highly conservative for two reasons.
1.
Cabling in the room constitutes the vast majority of the combustible load (approximately 80%). Th'e calculations do not consider that approximately one third of these cables are wrapped with a one-hour barrier.
2.
The non-Jacketed armor interlock cable, while higher in potential heat con-tent than cellulose based materials, is non-propagating. Therefore, it is highly unlikely that cabling beyond the origin of the fire would become involved.
Conclusions Based on the maximum potential fire load included in these calculations, it is not possible for sufficient heat to be developed for the duration needed to result in failure of any tmprotected cable tray supports.
,/I@b.<2~ee4, J. M. Rucci Design Engineer I JMR/mdc a
i 1 NFPA Fire Protection Handbook,15th Edition. Section 5, Chapter 9, Subsections A.and B.
2ASTM E119-81, Standard Method of Fire Tests of Building Construction and Mate-rials, Appendix Section X6.3.
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