ML20147D514

Request for Addl Info on Proposed Sys for Core Cooling & Effects of LOCA W/Encl Questionnaire

ML20147D514
Person / Time
Site:	Zimmer
Issue date:	10/10/1978
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Borgmann E CINCINNATI GAS & ELECTRIC CO.
References
NUDOCS 7810140095
Download: ML20147D514 (5)

Text

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, a p tro g*o UNITED STATES y" /, NUCLEAR REGULATORY COMMisslON

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. WASHINGTON D. C. 20555

%, ... / OCT 101978 Docket No: 50-358 Mr. Earl A. Borgmann Vice President - Engineering Cincinnati Gas.& Electric Company P. O. Box 960 Cincinnati, Ohio 45201

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - WM. H. ZIMMER, UNIT NO.1 In order that we may continue our review of your application for a license to operate the Zimmer Nuclear Power Station, Unit No.1, your response to the enclosed positions (and requests for additional information) are needed. The positions (and requests) are based upon information contained in your application as amended through Revision 46 and your response to our previous requests.

To maintain our review schedule, we will need your response to these positions (and requests) by November 15, 1978. If you cannot meet this date, please advise us within two weeks of receipt of this letter of your date for complete response.

Please contact us if you desire information or clarification regarding the Enclosure.

Sincerely, f B .

John F. Stolz, Chief.s fght Water Reactors Branch No. 1 Division of Project Management

Enclosure:

Request for Additional Information cc: See page 2

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The Cincinnati Gas and Electric OCT 101978 Company cc: Troy B. Conner, Jr., Esq. Thomas A. Luebbers, Esq.

Conner, Moore & Corber Cincinnati City Solicitor 1747 Pennsylvania Avenue Room 214, City Hall Washington, D. C. 20006 Cincinnati, Ohio 45202 Mr. William J. Moran Mr. Stephen Schumacher General Counsel Miami Valley Power Project The Cincinnati Gas.and P O. Box 252 Electric Company Dayton, Ohio 45401 P. O. Box 960 Cincinnati, Ohio 45201 Ms. Augusta Prince, Chairperson 601 Stanley Avenue Mr. William G. Porter, Jr. Cincinnati, Ohio 45226 Porter, Stanley, Arthur and Platt 37 West Broad Street Columbus, Ohio 43215 Mr. Peter H. Forster, Vice President Energy Resources Teh Dayton Power and Light Company P. O. Box 1247 Dayton, Ohio 45401 J. Robert Newlin, Counsel The Dayton Power and Light Company P. O. Box 1034 Dayton, Ohio 45401 Mr. James D. Flynn Manager, Licensing Environmental Affairs The Cincinnati Gas and Electric Company P. O. Box 960 Cincinnati, 0hio 45201 Mr. J. P. Fenstermaker Senior Vice President - Operations Columbus and Southern Ohio Electric Company 215 North Front Street Columbus, Ohio 43215 David B. P -!hauser, PhD 3569 Nine Mile Road Cincinnati, uhio 45230

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ENCLOSURE WM. H. ZIMMER ROUND-lWO QUESTIONS Introduction This enclosure consists of the nineteenth in a series of Round-Two positions (and requests for additional information). We will need your response to them in order to complete our safety evaluation of your Zimmer OL application. The position (and requests) are in the area of:

212.0 Reactor Systems As our review continues you may expect Round-Two positions (and requests in other areas not listed and possible additional requests in the above area.

It will be helpful to us if your responses' are in a " Position and Response" format using the same number designation as the position.

The first number designated the review area and the second (in parentheses) designated the associated section of the FSAR. Of course, your responses should include revision to the FSAR wherever appropriate

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212.72 Your responses to Questions 212.55 and 212.67 are incorplete.

(6.3) Nrcostrate that your proposed system for I.PCI fle 1 diursion to untwell spray cooling in the event of a I.0CA will s.ot adversely affect core cooling. Discuss the effects of the following on core cooling and provide the necessary infor: ration to show that the requirev.ents of GDC 35 of Appendix A to 10 CFR 50 and para. 50.46 of .10 CFR 50 are not violated as a ,

result: .

(1) Justify that the system provided for diversion of LPCI flow nects single failure criteria so that diversion before 10 minutes need not be considered.

(2) Justify the conclusion that a break in the HPCS line is the rmst limiting location when evaluating LOCA with diversion.

(3) Justify the result that a diesel failure causing loss of the LPCS is more limiting than a loss of the LPCI for core cooling.

Discuss the relative effects of these low pressure systems

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upon the paran,eter's in the LOCA calculations, e.g. , reflood, core heat transfer,in your justification.

(4) Provide a sensitivity study showing peak clad temperature as a function of break size for small break LOCA's assuming diversion will be initiated at 10 minutes. Perform this study for HPCS and recirculation line breaks. For the rest limiting break, provide the following figures:

(a) Water level inside the shroud as a function of time during the LOCA (b) Reactor vessel pressure vs. time (c) Convective heat transfer coefficient vs. time (d) Peak clad temperature vs. time (e) ECCS flow rate vs. time.

(5) Justify that diversion at times greater than 10 minutes will have less severe consequences than diversion at 10 minutes (considering appropriate break sizes for later diversion).

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212.75 The applicant has presented a 1.0CA analysis for a limiting small break with LPCI diversion at 10 ninutes. The applicant

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must justify that this analysis bounds all possible LPCI

• diversion scenarios considering wetwell spray, dry well spray and suppression pool cooling, and assuming a single failure.

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