ML20137G707

Forwards Updated Status of RAI Open Items & Comments on Responses Where Staff Needs Addl Details from W

ML20137G707
Person / Time
Site:	05200003
Issue date:	03/28/1997
From:	Huffman W NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9704010479
Download: ML20137G707 (4)

Text

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March 20, 1997

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Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Analysis Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230

SUBJECT:

AP600 OPEN ITEM STATUS UPDATE RELATED TO THE TESTING PROGRAM I l

i

Dear Mr. Liparulo:

Westinghouse letters NSD-NRC-97-4962 dated January 30, 1997, and NSD-NRC 4977 dated February 7, 1997, provided responses to the staff's requests for l additional information (RAIs) on the AP600 reactor systems testing program.

l The staff has reviewed these RAI responses and closed out those that were l

satisfactory. In some cases, the Nuclear Regulatory Commission staff has some additional questions concerning the Westinghouse responses which Westinghouse needs to clarify by further discussions with the staff.

Enclosed is an updated status of the RAI open items and comments on those J

responses where the staff needs additional details from Westinghouse, i 1

If you have any questions regarding this matter, you can contact me at 1 (301) 415-1141. l l

Sincerely, i original signed by:

William C. Huffman, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation l

Docket No.52-003 j l

Enclosure:

As stated i

cc w/ enclosure:

See next page bbNbd bbhi l DISTRIBUTION:  !

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ACRS (11) JLyons, 0-8 E23 GHolahan, 0-8 E2 Alevin, 0-8 E23 DOCUMENT NAME: A: TEST-RAI STS n ... .ni,i..w. i w: c . c ,y wnham .it. chm.nu.ncbow. *E' = Copy wkh .tt.ctwn.nt/.ncionw. *N' = No copy 0FFICE PM:PDST:DRPM l SRXB: DSS.A-,l D:PDST:DRPM l NAME WCHuffman:kgr % Alevi4# 7 h TRQuay-nh DATE 3 fQ97 3 /p /TV / 3/W/97 I 9704010479 970328 ~# #

PDR ADOCK 05200003 E PDR 4

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b d Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 l  !

i cc: Mr. B. A. McIntyre Mr. Ronald Simard, Director i Advanced Plant Safety & Licensing Advanced Reactor Programs l Westinghouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776 Eye Street, N.W. ,

P.O. Box 355 Suite 300  !

Pittsburgh, PA 15230 Washington, DC 20006-3706  !

Ms. Cindy L. Haag Ms. Lynn Connor Advanced Plant Safety & Licensing noc-Search Associates Westinghouse Electric Corporation  ? cst Office Box 34 Energy Systems Business Unit Cabin John, MD 20818 Box 355 Pittsburgh, PA 15230 Mr. James E. Quinn, Projects Manager LMR and SBWR Programs Mr. M. D. Beaumont GE Nuclear Energy Nuclear and Advanced Technology Division 175 Curtner Avenue, M/C 165 Westinghouse Electric Corporation San Jose, CA 95125 One Montro;e Metro 11921 Rockville Pike Mr. Robert H. Buchholz l Suite 350 GE Nuclear Energy 1 Rockville, MD 20852 175 Curtner Avenue MC-781 San Jose, CA 95125 Mr. Sterling Franks U.S. Department of Energy Barton Z. Cowan, Esq.

NE-50 Eckert Seamans Cherin & Mellott 19901 Germantown Road 600 Grant Street 42nd Floor Germantown, MD 20874 Pittsburgh, PA 15219 Mr. S. M. Modro Mr. Ed Rodwell, Manager Nuclear Systems Analysis Technologies PWR Design Certification Lockheed Idaho Technologies Company Electric Power Research Institute Post Office Box 1625 3412 Hillview Avenue Idaho Falls, ID 83415 Palo Alto, CA 94303 Mr. Frank A. Ross Mr. Charles Thompson, Nuclear Engineer l U.S. Department of Energy, NE-42 AP600 Certification Office of LWR Safety and Technology NE-50 19901 Germantown Road 19901 Germantown Road Germantown, MD 20874 Germantown, MD 20874  !

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l AP600 TESTING RAI STATUS i NSD-NRC-97-4962 dated January 30. 1997. RAI Response Status:

440.375 -------------------- Closed

, 440.380 -------------------- Closed j 440.381 -------------------- Closed 440.383 -------------------- Closed 440.388 -------------------- Closed 440.571 -------------------- Closed 440.572 -------------------- Closed 440.574 -------------------- Closed l

l 440.573 -------------------- Action W l

The rationale (part (a)) here is still not clear. Why should backpressure

have any significant impact early in the transient, when flow is critical and l

(presumably) largely independent of backpressure 7 (Note: the Westinghouse response does not explain the behavior; it merely restates the question and attributes it to backpressure with no specific justification.) The same question applies to part (b): granted that the saturation temperature at containment pressure is higher; however, as long as the primary system pressure is greater than containment pressure, what is happening in the core should not be significantly influenced by the containment conditions (except at the interface, if the flow is not critical)--and the question specifically referred to the initial depressurization phase, when the primary pressure is still well above containment pressure. In addition, if the explanation in part (c) of the response is correct, and the liquid break flow is higher for SB19, this would appear to decrease primary system inventory more rapidly and lead to an earlier transition to CMT draining, rather than a later transition as observed in the test. And if containment pressure really influenced early in-vessel behavior, a lower containment pressure (S818) would cause a higher void fraction for the same quality, increasing the mixture level in the vessel, and presumably promoting the continuation of recirculation, again the opposite of what was observed.

NSD-NRC-97-4977 dated February 7. 1997. RAI ResDonse Status:

l 440.197 -------------------- Closed 440.395 -------------------- Closed 440.570 -------------------- Closed 440.577 -------------------- Closed 440.581 -------------------- Closed 440.582 -------------------- Closed 440.575 -------------------- Action W 1

Why do the center and peripheral temperature histories differ after about 600 sec?

i I Enclosure l

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4 e ..

4  :

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440.576 -------------------- Action W i Westinghouse commits in this response to provide an uncertainty ' analysis for I

OSU by February 17, 1997. The staff is still waiting for this response. i 440.580 -------------------- Action W

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Although the explanation provided by Westinghouse may be accurate and the j assertion that PRHR thermal energy has a minor effect on the overall energy  !

balance may also be correct, the staff like to see this item addressed in the  !

to-be-provi6ed error / uncertainty analysis (see RAI response 440.576 - i.e.,  !

1 the uncertainty as'sociated with derived quantities). I

! I Other Miscellaneous Testina Open Item Status Updates:

{

i j 440.369 -------------------- Closed

440.524 -------------------- Closed '

4 440.525 -------------------- Closed 440.526 -------------------- Closed l 440.527 -------------------- Closed i 440.407 -------------------- Closed j 440.566 -------------------- Closed

i

0ITS Item 2659 ------------- Closed OITS Item 3104 ------------- Closed i

i OITS Item 1628 ------------- Resolved

.