ML19269D129

Forwards Info Re Applicant'S Position on NUREG-0487, Open Issues Concerning Mark II Containment Program, & Lead Plant Load Acceptance Criteria in Response to NRC 790202 Ltr

ML19269D129
Person / Time
Site:	LaSalle
Issue date:	02/23/1979
From:	Delgeorge L COMMONWEALTH EDISON CO.
To:	Parr O Office of Nuclear Reactor Regulation
References
NUDOCS 7902270362
Download: ML19269D129 (4)

Text

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Commonwealth Ecison one First National Plaza. Chicago. Ilknois Address He,.'y to: Post Ofhce Box 767 Chicago, Illinois 60690 February 23, 1979 Mr. Olan D. Parr, Chief Light Water Reactors - Branch 3 Division of Project Management U.S. Nuclear Ragulatory Commission Washington, D.C. 20555

Subject:

LaSalle County Station - Mark II Lead Plant Acceptance Criteria (NUREG-0487)

NRC Docket Nos. 50-373 and 50-374 Reference (a) : O. D. Parr letter to B. Lee, Jr.

dated February 2, 1979

Dear Mr. Parr:

This transmittal responds to the request for informa-tion contained in Reference (a). Specifically, information is provided relative to the Commonwealth Edison position on NUREG-0487 and open issues concerning the Mark II containment Program as applied to LaSalle County Units 1 and 2.

The LaSalle County Design Assessment Report has been amended to include a commitment to adopt the Mark II Lead Plant Criteria with limited exceptions. These exceptions, which have each been addressed as open items in the Mark II Program, were reviewed with members of the NRC Staff during the week of February 12, 1979.

The attac.Nnent to this letter either responds to or provides a schedule for response to the NRC information requests contained in Enclosures 1 and 2 of Reference (a). In each case, it is expected that all outstanding information will be available by March 1979. At that time, the additional information will be transmitted to the NRC and appropriately referenced on the LaSalle County dockets.

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Commonwealth Edison NRC Docket Nos. 50-373/374 Mr. Olan D. Parr: February 23, 1979 As you know, resolution of the containment issue is essential to the closure of the LaSalle County safety review.

For this reason, we request that the information discussed in the attachment to this letter be reviewed expeditiously. It is worth noting that the Commonwealth Edison commitment relative to NUREG-0487 was docketed in December 1978 but was not recognized in Reference (a) , (DAR Revision 4, Appendix ( dated December 1978) .

Please direct any further questions in this regard to this office.

Very truly yours, L. O. DelGeorge Nuclear Licensing Administrator Boiling Water Reactors attachment

NRC Docket Nos. 50-373 ATTACH:ENT 50-374 Information Request.

Lead Plant Load Acceptance Criteria

1. Pool Swell Elevation and Wetwell Air Compression As indicated in the LaSalle County Station, Design Assessment Report, Appendix C, these NRC criteria will be met.

2. Small Structure Impact Loads As indicated in the LaSalle County Station (LSCS)

Design Assessment Report (DAR), Appendix C, this criteria be met.

3. Asymmetric Pool Swell Loads As indicated in the LSCS, DAR, Appendix C, the effect of this load on the containment boundary has been

\ assessed, and it was determined to be a noncontrolling load for design. On this basis the criteria will be met; however as discussed with the NRC staff in a Mark II Containment Owners Group meeting on February 13, 1979 a generic Owners Group Criteria will be submitted in March 1979.

4. Submerged Boundary Load During Vent Clearing As indicated in the L3CS, DAR, Appendix C the effect of this load on the containment boundary has been assessed, and it was determined to be a noncontrolling load for design. On this basis the criteria will be met; however further justification of the Mark II Owners Group criteria will be provided in March 1979. This justification was discussed in a meeting with the NRC staff on February 13, 1979.

5. LOCA/SRV Submerged Drag Loads

a. LOCA Water Jet (1) Ring Vortex Model A detail technical description of this model was presented to the NRC staff at the Mark II Owners Group meeting on February 13, 1979. A Mark II generic report will be provided in March 1979.

(2) Acceleration Drag As indicated in LSCS, DAR, Appendix C acceleration drag will be included in the assessment of the loads due to the LOCA Water Jet.

b. Unpublished Sarpkaya Data The methods for evaluating submerged structure drag loads for LSCS were presented to the NRC staff at a meeting on December 12, 197S. As indicated in that meeting, appropriated published data will be used to determine the modified drag coefficient for unsteady

NRC Docket Nos. 50-373

" 50-374 but non-oscillatory flow. In our judgement sub-mittal of this data is unnecessary; however we will attempt to expedite generic resolution of four concern.

c. Sensitivity Studies for Selection of Equivalent Uniform Flow Fields This study was described to the NRC staff in a meeting on Decembet 12, 1978. A more detailed description will be provided in an amendment to the LSCS, DAR in March 1979,

d. Guidelines for Interference Effects The basis for including interference effects in

• submerged structure load evaluations was discussed at a meeting with NRC staff on December 12, 1978.

A more detailed description will be provided in an amendment to the LSCS, DAR in March 1979.

' e. T-Quencher Water Jet Zone of Influence

' The zone of the influence used for LSCS was presented to the NRC staff in a meeting on December 12, 1978.

A description of this zone of influence and the pro-posed experimental justification will be documented in an amendmdnet to the LSCS, DAR in March 1979.

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! 6. SRV Bubble Phasing The detailed methodology will be documented in an

' amendment to the LSC3 DAR in March 1979.

7. SRV Bubble Frequency i The presentation made at the NRC/ Mark II Owners meeting a

on February 13, 1979 will be documented by the " Lead This document will confirm the Plants" in April 1979.

- conservatism of the ramshead load definition which was used for the final load assessment of LSCS.

8. Chugging FSI A generic reply to the NRC staff questions will be sub-mitted in March 1979.

9, Load Combinations - Load Case No. 10 At the NRC/ Mark II Owners meeting on February 13, 1979, the March II Owners presented justification for ignoring this load combination. Pending response from the NRC staff,

' the LSCS application of this load case will remain as described in the LSCS, DAR, Appendix C.

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