ML20211A908
| ML20211A908 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 09/16/1997 |
| From: | Huffman W NRC (Affiliation Not Assigned) |
| To: | Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 9709250008 | |
| Download: ML20211A908 (4) | |
Text
.______ ____________ _ _ _ _ - __ - _ _ _
September 16, 1997 I
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:
REQUESTS FOR ADDITIONAL INFORMATION (RAls) ON THE AP600 STANDARD SAFETY ANALYSIS REPORT (SSAR) CHAPTER 15 ACCIDENT ANALYSES AND THE APPLICATION OF WCOBRA/ TRAC
Dear Mr. Liparulo:
The Nuclear Regulatory Commission (NRC) is still reviewing the AP600 Chapter 15 Accident Analyses. Based on recent discussion between the staff i
and Westinghouse on the Chapter 15 analyses and the application of WCOBRA/ TRAC to these analyses, the staff has determined that additional information will be needed to complete its review. The staff's RAls on the Chapter 15 analyses and related WCOBRA/ TRAC application are provided as an enclosure to this letter.
If you have any questions regarding this matter, you may contact me at (301) 415-1141.
Sincerely, original signed by:
William C. Huffman, Project Manager Standardization Project Directorate Divisi m of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003
Enclosure:
As stated LEh h fSOQfy cc w/ encl:
See next page DISTRIBUTION:
Docket File PDST R/F TQuay 0[.;> }
PUBLIC TKonyon BHuffman JSebrosky DJackson JMoore, 0-15 B18 WDean, 0-5 E23 ACRS (11)
GHolahan, 0-8 E2
- 1. i SNewberry, 0-8 E2 TCollins, 0-8 E23 Alevin, 0-8 E23 SSun, 0-8 E23 Llois, 0-8 E23
',; d 6 0 3 3 DOCUMENT NAME: A:CH15-3.RAI is receive a copy of tMa decismont,Indcate in the bec *C" = Copy wMhout attachment / enclosure "E' = Copy with attachment / enclosure
- N* = No copy 0FFICE PM:PDST:DRPM SC:SRXB:DSSA D:PDST:DRPM l
NAME WCHuffma h Alevr %
TRQuay 4 W DATE 09/t3/97 09fsf/X1 09/6/97 9709250000 970916 PDR ADOCK 05200003 E
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Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600
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cc: Mr. B. A. McIntyre Mr. Russ Bell Advanced Plant Safety '. Licensing Senior Project Manager, Prcgrams Westinghouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776 I Street, NW P.O. Box 355 Suite 300 Pittsburgh, PA 15230 Washington, DC 20006-3706 l
Mr. Cindy L. Haag Ms. Lynn Connor Advanced Plant Safety & Licensing Doc-Search Assee.iates Westinghouse Electric Corporation Post Office Bo; 34 Energy Systems Business Unit Cabin John, MD 20818 Box 355 Pittsburgh, PA 15230 Dr. Craig D. Sawyer, Manager Advanced Reactor Programs Mr. S. M. Modro GE Nuclear Energy Nuclear Systems Analysis Technologies 175 Curtner Avenue, MC-754 Lockheed Idaho Technologies Company San Jose, CA 95125 Post Office Box 1625 Idaho Falls, ID 83415 Mr. Robert H. Buchholz l
GE Nuclear Energy Mr. Sterling Franks 175 Curtner Avenue, MC-781 t
U.S. Department of Energy San Jose, CA 95125 NE-50 l
19901 Germantown Road Barton Z. Cowan, Esq.
Germantown, MD 20874 Eckert Seamans Cherin & Mellott 600 Grant Street 42nd Floor Kr. Frank A. Ross Pittsburgh, PA 15219 U.S. Department of Energy, NE-42 Office of LWR Safety and Technology Mr. Ed Rodwell, Manager 19901 Germantown Road PWR Design Certification Germantown, MD 20874 Electric Power Research Institute 5412 Hillview Avenue Mr. Charles Thompsen, Nuclear Engineer Palo Alto, CA 94303 AP600 Certification NE-50 19901 Germantown Road Germantown, MD 20874
U.S. NUCLEAR REGULATORY COMMISSION REQUESTS FOR ADDITIONAL INFORMATION ON WESTINGHOUSE AP600 SSAR CHAPTER 15 ACCIDENT ANALYSES AND RELATED WCOBRA/ TRAC APPLICATION RAI 44.726 SSAR Table 15.6.5-4 lists the initial and boundary conditions used for the break spectrum sensitivity study to identify the limiting break case.
These conditions are determined as a worst set of combination that will result in the limiting calculated PCT.
In a September 11, 1997 phone call between Westinghouse and the NRC, Westinghouse stated that these initial conditions (ICs) were determined from a sensitivity study based on the LOCA analyses for a break with 80 percent of the DECLG area Table 15.6.5-8, the same set of ICs was ass (CD-0.8). As shown in SSAR umed in the analysis for cases with CDs of 0.3 through 1.0 in determination of the limiting break size.
It is not clear that this set of ICs is independent cf break sizes.
Please discuss the need for changing the bounding ICs as the break size varies and justify the adequacy of the use of the same set of ICs in Table 15.6.5-4 for the determination of the limiting break case.
RAI 440.727 WCAP-14776 does not identify nor reference tha relationship of the OSU experiments to the AP600.
In particular, no arguments are justify the parameter ranges (temperature, flows, pressure, presented that etc.) are representative of the corresponding parameters to be used in the AP600.
Please document the OSU relationship including applicable parameter ranges.
RAI 440.728 WCAP-14776 states that WCOBRA/ TRAC (LBLOCA version) and NOTRUMP will be used to specify the initial conditions (ICs) for the large and small break LOCAs respectively, followed by the analysis of the long term cooling (LTC) phase using WCOBRA/ TRAC (LTC version).
However, there is r.o identification of the ICs resulting from a LBLOCA.
Please complete the analysis with the presentation of the Its resulting from a LBLOCA and the qualification of WCOBRA/ TRAC to analyze the LTC for these ICs.
RAI 440.729 In Chapter 15.6.$.4C.3.1, the DECLG break transient analysis is presented.
This is an extended initial transient to 1500 seconds.
The nodalization is that used in the LBLOCA and (presumably) the code used is the WCOBRA/ TRAC as qualified for the LBLOCA.
However, from Figure 15.6.5.4C.3.1-1 is apparent that the core is quenched at about 120 seconds. The continuation of the Enclosure
. I transient analyses should be performed with the WCOBRA/ TRAC version qualified I
for LTC.
Please present arguments to justify the use of the WCOBRA/ TRAC (qualified for LBLOCA) in the portion of this transient from 120 seconds to 1500 seconds.
RAI44b.730 In a September 11, 1997 conference call, Westinghouse confirmed that credit is taken for control rod insertion during SBLOCA analyses for breaks up to 30-inches.
It is not clear whether any control rod insertion is assumed in analyses for LBLOCAs including the 12-inch break discussed in the response to RAI.440.66.
SRP 15.6.5, item III.4.e, states that appropriate analyses are needed to support any credit taken for control rod insertion.
Please provide i
information on the control rod model assumed in the SBLOCA analyses, that the control rod insertion model for the SBLOCA analyses is acceptable for breaks l
with the range up to a 10-inch break, and justify or provide adequate analyses i
to demonstrate that the rods can insert into the core under the assumed break conditions. The request is also applicable to the LBLOCA analyses if the analyses take credit for control rod insertion, s
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