NRC-87-0108, Forwards Suppl to 870427 Proposed Change to Tech Spec 3/4 6.1.7 Re Drywell Average Air Temp,Including Rev 3 to NEDO-24568, Mark I Containment Program Plant-Unique Load Definition,Enrico Fermi Atomic Power Plant Unit 2

Forwards Suppl to 870427 Proposed Change to Tech Spec 3/4 6.1.7 Re Drywell Average Air Temp,Including Rev 3 to NEDO-24568, Mark I Containment Program Plant-Unique Load Definition,Enrico Fermi Atomic Power Plant Unit 2

ML20237J432
Person / Time
Site:	Fermi
Issue date:	08/14/1987
From:	Sylvia B DETROIT EDISON CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20237J435	List: ML20237J456 ML20237J471 NRC-87-0108, Forwards Suppl to 870427 Proposed Change to Tech Spec 3/4 6.1.7 Re Drywell Average Air Temp,Including Rev 3 to NEDO-24568, Mark I Containment Program Plant-Unique Load Definition,Enrico Fermi Atomic Power Plant Unit 2
References
CON-NRC-87-0108, CON-NRC-87-108 TAC-65174, NUDOCS 8708180177
Download: ML20237J432 (5)

Text

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, B. Ralph Syltia p Group Vice Preludent Detrol! 6400 North Dixie Hi Edison =w ghway l

l August 14, 1987 I NBC-87-0108 U. S. Nuclear Regulatory Comission  !

Attn Document Control Desk Washington, D. C. 20555

References:

1) Fermi 2 NBC Docket No. 50-341 NBC License No. NPF-43

2) Detroit Edison Letter to NBC, " Proposed 'Ibchnical Specification Change - Drywell Average Air Temperature l (3/4 6.1.7) ," VP-NO-87-0035, dated April 27, 1987 j

Subject:

Supplement to Proposed Technical Specification Change -

Drywell Averace Bjr 'Ibmperature (3/f_fd,])

Detroit Mison is providing herein supplemental information in response to an NBC question regarding the effect of the design drywell heat .ad (9 MB'IU/HR) on the normal and emergency cooling water systems and associated equipment.

In response to this question, Detroit Mison performed a review on the General Service Water System (GSW), Reactor Building Closed Cooling Water System (RBOCW) ard Emergency Equipment Cooling Water System (EEN) design calculations and has verified that the design drywell heat load value of 9 MB'IU/HR was utili7ed in these calculations. A summary of the calculated drywell heat load is provided in Attachment 1. The design calculations conclude that sufficient cooling is provided to all essential equipnent outside the drywell.

Since the G9f, RDOW and EEG systems ere designed for the -

characteristic drywell heat load, no unacceptable consequences, such as vapor locking, steam binding or water hammer is expected. A sunmary of the RBOCW and EEG system operation is provided in Attachment 2. Two (2) related docunents (IEDO-24568 Rev. 3, dated April 1982 and MDC-DBCO-04-3336, Rev. 1, dated August 1985 with Supplemental Letter, dated July 14, 1987) are also provided, at your request, in Attachments 3 and 4.

Detroit Mison is also providing, for your review, supplemental information regarding the basis for requesting a Technical Specification temperature of 145 F. Detroit Edison initiated a review of the original design heat load calculation due to industry (

r. g 8700100177 h0BDO 41 l l PDR ADOCK PDR 3

USimC August 14, 1987 l tac-87-0108 Page 2 feedback of plants experiencing higher than expected drywell i temperatures. The original design heat load calculation (perforned in 1973) estimated that a maxinum 5.3 MBW/HR could be expected in the drywell. The original calculation was revised arrl a more detailed calculation performed to incorporate startw]p test and design data. ,

The revised design heat load calculation, based upon both rated thermal power operation and a maxinum lake water tgnperature of 85 F (inlet temperature to RBCOf and EECW oystens of 95 F), estimates that a maxinum 9 MBW/HR could be expected in the drywell. This maxinum heat load value corresponds to the heat removal capagility for maintaining the drywell at an equilibrium temperature of 145 F. At intermediate power levels (25-40 percent rated thermal power) with less than rated recirculating pump motor speed and lower feedwater temperatures, the drywell heat load is reduced to approximately 7 MBTU/HR. This heat load value corresponds to the heat removal capgbility for maintaining the drywell temperature below the current 135 F Technical Specification temperature limit.

The drywell temperatures recorded to date are approaching g 135 F as the lake water temperatures increase above 75 F. Fermi 2 currently has not reached its expected drywell equilibrium temperature due to the limited power operation of the plant. The heat load calculations presented herein are based upon maxinum design conditions at rated thermal power operation. It is expected that these calculations are l conservative for maintaining the drywell temperatures (during normal  !

operation) below 145 F.

If you have any questions, please contact Mr. Steven Frost at (313) 586-4210.

Sincerely, f 0 k Enclosure cc: A. B. Davis j E. G. Greenman i W. G. Rogers l J. J. Stefano I

L _ ___ _-_ _ _

4 Attachment 1 Sumary of Total Contit.uous Drywell Heat Load '(MBTU/HR)

1) Pipe insulation 1.85

2) Vessel 1.59

3) Stabilizer lug bracket 0.13

4) CRD piping 0.05

5) Refueling bellows seal 0.09

6) ' Vessel support skirt 0.23

7) Drywell cooler fan motors 1.20

8) Recirculating punp motors 2.29

9) SRW 0.20

10) Unidentified leakage .

0.99

11) Sacrificial shield graca heat 0.01

12) CRDs & PNs 0.31 TOTAL 8.94 MB1U/HR

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Attachment 2 RIOCW System Operation

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_ Sa Reactor Building Closed Cooling Water System (RBOCW) is designed - q to remove the heat load from both essential and non-essential L -equipment located in the Reactor Building and the drywell. These ~

loads are calculated at rated thermal pcmer and include an-approximate 9 MBTU/HR heat load for the drywell. Se total heat load for the RB00W system (including the drywell) is approximately 52 MBW/HR. The RB006 heat exchanger design capacity is approximately 68 MBW/HR, which when conpared to the loading, results in an excess capability of 16 MBW/HR. . Se current design basis provides that under loss-of-coolant accident (140A) conditions without loss of power or a i low RB00f pressure, the RB004 system would initially provide cooling to the essential and nonessential loads. As the IEA progresses an

' increase in RB00W heat exghanger exit temperature would occur. Wis

. variable is alarmed at 85 F. The Alarm Response Procedures ,

Lspecified several actions including' increasing the General' Service Water flow to the RBTH. system. Should this not result in an adequate temperature reduction, the EBOW system would be activated by the operator. 'ne drywell would be automatically isolated upon the concurrent loss of RB00f and a high drywell pressure signal.

EBOf System Operation Se Emergency Equignent' Cooling Water System (EB04) is designed to remove the heat load from both essential and non-essential equipment located in the Reactor' Building and the drywell should the RB00W system become unavailable. The EBOi system is divided .into two j divisions with power supplied by the Emergency Diesel Generators and '

cooling water by the Emergency Equipment Service Water system. Should

- a loss of offsite AC power or loss of cooling water pressure in the RBOCH system occur, both divisions of the EBOW system would

>. automatically initiate. The total heat load for normal operation of both divisions is:approximately 15 MBTU/HR. - The EBOi heat exchanger

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design capacity is approximately 22 MBTU/HR, which when conpared to r the loading, results in an excess capability of 7 MBW/HR.

yb Failure of a single division of the EBOW system would result in heat removal capability of approximately 11 MBW/HR, which is below the 15 MBW/HR total heat load at rated thermal power. Continued operation would be controlled by technical specification operability and temperature requirements. ,

Should a LOCA occur at the same time that the EBOf system is operational, the additional drywell heat load and the non-essential heat load would exceed the capability of the EBOf system to provide cooling service to all the essential equipment. As a result of this potential ~ condition, the non-essential drywell portion of the divisions would be automatically isolated upon receiving both a high ,

drywell pressure signal and activation of EBOf signal. The elimination of the drywell portion of the heat load would result in excess capacity directed to the non-drywell essential equipment.

Attachment 3 i

NEDO - 24568 Rev 3 (April 1982) 4

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