ML17177A307

Requests Addl Info Re Studies Performed to Justify Isolation of Qualified Svc Water from ECCS Room Coolers at Dresden & to Justify That Low & High Pressure Coolant Injection Pump Room Coolers Not Needed at Quad Cities

ML17177A307
Person / Time
Site:	Dresden, Quad Cities
Issue date:	03/04/1992
From:	Olshan L Office of Nuclear Reactor Regulation
To:	Kovach T COMMONWEALTH EDISON CO.
References
TAC-M81264, TAC-M81265, TAC-M82692, TAC-M82693, NUDOCS 9203130164
Download: ML17177A307 (5)

Text

March 4, 1992 *

.Docket Nos. 50-237, 5d-249 and 50-254, 50-265 DISTRIBUTION:

(Jj.(kel~fjJ_s NRC & Local PDRs PDIII-2 r/f OFC NAME DATE

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Mr. Thomas J. Kovach B. Boger.

J. Zwolinski R. Barrett C. Moore (:2.)

Nuclear Licens~ng Manager Commonwealth Edison Company-Suite 300 L. Olshan B. Siegel OGC ACRS(lO)

OPUS West III

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B. Clayton, RIII PDIII-2 Plant File 1400 OPUS Place Downers Grove, Illinoi~ 6051S

SUBJECT:

ASSESSMENT Of ECCS *OPERAlfILITY WITHOUT THE ROOM COOLER HEAT REMOVAL CAPABILITY*.~QRESDEN/QUAD'CITIES *(TAC NOS. M81264, M81265, M82692, AND M82693). *1

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Studies that.* you have performed* were us,ed to justify the i so 1 at ion of I.

qualified service water from the EC~S ro~m ~bOlers at Dresden arid also used to justify that low and high pressure coolant injection pump room coolers were not needed at Qua~ Cities.

We '~re evaluating these studies and need

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additional information to complete' our evaluation.. Please respond to the enclosed request for additional information.within 30 days of the date of this letter.

Enclosure:

Request for Additional Information cc w/enclosure:

See next page

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Sincerely,.

Original signed by:

• Leonard N. Olshan Leonard N. Olshan, Project Manager

.Project Directorate 111-2 Division of Reactor Projects - 111/IV/V Office of Nuclear Reactor Regulation *

3 I 'I /92 I I

Mr. Thomas J. Kovach Commonwealth Edison Company cc:

Michael I. Miller, Esquire Sidley and Austin One First National Plaza Chicago, Illinois 60690 Mr. C. Schroeder Plant Manager Dresden Nuclear Power Station Rural Route #1 Morris, Illinois 60450 U. S. Nuclear Regulatory Commission Resident Inspectors Office Dresden Station Rural Route* #1 Morris, Illinois 60450 Chairman Board of Supervisors of Grundy County Grundy County Courthouse Morris, Illinois 60450 Regional Administrator Nuclear Regulatory Commission, Region III

. 799 Roosevelt Road, Bldg. #4

. Glen Ellyn, Illinois 60137 IJlinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, Illinois 60601 Dresden Nuclear Power Station Unit Nos. 2 and 3

Mr. Thomas J. Kovach Commonwealth cc:

Mr. Stephen E. Shelton Vice President Iowa-Illinois Gas and Electric Company P. 0. Box 4350 Davenport, Iowa 52808 Michael I. Miller, Esquire Sidley and Austin One First National Plaza Chicago, Illinois 6069.0 Mr. Richard Bax Station Manager Quad Cities Nuclear Power Station 22710 206th Avenue North Cordova, Illinois 61242 Resident Inspector U. S. Nuclear Regulatory Commission 22712 206th Avenue North Cordova, Illinois 61242 Chairman Rock Island County Board of Supervisors 1504 3rd Avenue Rock Island County Office Bldg.

Rock Island, Illinois 61201 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety

• 1035 Outer Park Drive Springfield, Illinois 62704 Regional Administrator, Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, Illinois* 60601 Quad Cities Nuclear Power Station Unit Nos. 1 and 2

Enclosure REQUEST FOR ADDITIONAL INFORMATION REGARDING ASSESSMENT OF ECCS OPERABILITY WITHOUT THE ROOM COOLER HEAT REMOVAL CAPABILITY DOCKET NOS. 50-237, 50-249, 50-254, AND 50-265 During an inspection at Dresden Nuclear Power Station, concerns were identified regarding the isolation of Diesel Generator Cooling Water (DGCW) flow to the emergency core cooling system (ECCS) pump room coolers.

Cormnonwealth Edison Company (CECo or the licensee) isolated flow of DGCW to the ECCS pump room coolers at Dresden Station following completion of an on-site review of a study providing technical justification for this action. A similar study and on-site review concluded that certain ECCS pump room coolers were no longer required as attendant equipment at the Quad Cities Station. The Office of Nuclear Reactor Regulation has been requested to assess the operability of ECCS equipment without the room cooler heat removal capability at the Dresden and Quad Cities Stations. The Plant Systems Branch has reviewed the study, "ECCS Pump Room Transient Response to Loss of Room Cooler for Dresden Station Units 2 and 3" (RSA-D-90-01), and the on-site review of this report (number 90-23 Rev. 1).

Based on our review, the staff requests that the licensee ~rovide additional information to address the concerns identified below for both facilities.

1.

The study states that heat loads used in the analysis are assumed to be equal to the room cooler capacities. It is not clear that this assumption provides a conservativ~ me~sure of the heat generation within each ECCS pump room.

The licensee is requested to provide heat load calculations identifying each individual heat load for each ECCS pump room for the Dresden and Quad Cities Stations. The licensee is also requested to provide the associated room cooler capacity for each affected pump room.

2.

Failure of certain potentially unqualified components, such as the High Pressure Coolant Injection (HPCI) turbine gland seal condenser, may cause a substantial increase in the heat load for an individual ECCS pump room.

The licensee is requested to address the potential additional heat load imposed by failure of unqualified components within the ECCS pump rooms at Dresden and Quad Cities Stations.

• 3.

The study states that wall and ceiling concrete structures were modeled as heat sinks. The licensee is requested to identify the specific location of these heat sinks and describe the structure which constituted the ultimate heat sink for the Dresden model.

The licensee is also requested to describe how solar heat loads on exterior structures were accounted for in the model.

The corresponding study and similar information is also requested for the Quad Cities Station.

4.

A constant convection heat transfer coefficient was used in the Dresden model.

The licensee is requested to provide the basis for the values selected for each facility. The licensee is also requested to describe how the lower rate of heat transfer to horizontal surfaces with respect to vertical surfaces, under natural circulation conditions, was addressed by the models.

5.

6.

7.

8.

9.

• The analysis assumes a homogeneous mixing of air throughout the pump room.

The licensee is requested to describe the motive force which produces this mixing and provide the results of any testing performed which verified this assumption.

The results of the study indicate that bulk room temperature closely approaches or exceeds the equipment qualification temperature in certain ECCS pump rooms at Dresden Station. The licensee is requested to describe and provide the results of any testin_g or analysis which demonstrates that the local component temperature will not exceed the equipment qualification temperature and render the affected equipment inoperable when its service is required. The licensee is also requested to provide the temperature versus time profile utilized for qualification of affected electrical equipment.

The study states that LOCA environmental conditions for the adjacent areas are assumed throughout the transient at Dresden.

The licensee is requested~

to describe the assumed temperature versus time LOCA profiles for the relevant adjacent areas. Of particular interest to the staff is the response of the torus area temperature to a LOCA.

The conclusion of the study recommends that the ECCS room cooler systems be restored to service as soon as possible if continuous full capacity ECCS operation is deemed necessary.

The licensee is requested to describe results of any testing performed which demonstrates that DGCW is capable of supplying adequate flow to the emergency diesel generator and ECCS room coolers simultaneously. The licensee is also requested to address how this recommendation is intended to be implemented.

Appendix B to 10 CFR Part 50 requires that testing be performed which demonstrates that structures, systems and components. will perform satisfactorily in service. The licensee is requested to provide results of any testing which demonstrates that the ECCS components will perform satisfactorily without ECCS pump room cooler heat removal capability.