ML20129G977
| ML20129G977 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 09/23/1996 |
| From: | Diane Jackson NRC (Affiliation Not Assigned) |
| To: | Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 9610300296 | |
| Download: ML20129G977 (4) | |
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UNITED STATES g
S NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30eeHoot September 23, 1996 Mr. Nicholas J. Liparulo, Nanager l
Nuclear Safety and Regulatory Activities Nuclear and Advanced Technology Division i
Westinghouse Electric Corporation i
P.O. Box 355 Pittsburgh, Pennsylvania 15230
SUBJECT:
FOLLOWON QUESTIONS RELATED TO SPENT FUEL POOL IN THE AP600 STANDARD j
SAFETY ANALYSIS REPORT (SSAR) l
Dear Mr. Liparulo:
To support the Nuclear Regulatory Commission (NRC) Plant Systems Branch safety evaluation effort, the staff has determined it needs additional information to complete 10 review. A telephone conference call was held between Westing-house and the NRC staff on September 10, 1996, to discuss these requests for i
additional information (RAIs).
RAlf 410.297 The staff has reviewed Ttble 9.1-4 in the SSAR which presents the time to saturation and height of water above the spent fuel given a station blackout and a seismic event. The staff believes that the shortest time to spent fuel pool boiling may occur during the following scenario that is not included in SSAR Table 9.1-4.
The postulated scenario is: The AP600 unit undergoes a normal refueling outage where 1/3 of the core fuel assemblies are deposited into the spent fuel pool, the plant is operated at full power just long enough to allow the new core to become fully irradiated, then something happens to the AP600 plant that necessitates a full core offload. Should a station blackout or a seismic event then occur, the time to pool boiling could be shorter than the times presented in SSAR Table 9.1-4.
Therefore, the staff is requesting Westinghouse to evaluate this bounding scenario and document in SSAR Table 9.1-4, the time to spent fuel pool saturation and the height of water above the fuel at 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
RAlf 410.298 In SSAR Section 9.1.3.5, Westinghouse states, "the spent fuel pool is designed such that a water level is maintained above the spent fuel assemblies for at least 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following a loss of the spent fuel pool cooling system and without makeup." Based on Table 9.1-4 in the SSAR, credit is taken for water in the in-containment refueling water storage tank (IRWST) and/or refueling cavity which is assumed to be available for gravity drain to the spent fuel pool following a full core off-load and loss of spent fuel pool cooling. This action is not described in the SSAR.
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9610300296 960923 PDR ADOCK 0520 3
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Mr. Nicholas J. Liparulo September 23, 1996 t
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Based'on a conference call with Westinghouse, the staff now understands that i
no operator action is needed for this gravity drain operation.
Inventory from the refueling cavity /IRWST automatically gravity drains into the spent fuel pool via the fuel transfer tube and fuel transfer gate. This operation l
4 requires that the fuel transfer tube isolation valve and the fuel transfer gate remain open following a total core offload. Given this information, the l7 staff requests that:
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Westinghouse clearly describe in the SSAR how the gravity drain process works following a loss of spent fuel pool cooling given a total core offload. This description needs to include when the fuel transfer tube j
isolation valve and the fuel transfer gate are opened and how the status of these components will be controlled following a total core offload i
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(i.e. Technical Specifications).
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Westinghouse clarify in the SSAR that the spent fuel pool level instru-mentation is safety related.
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You have requested that portions of the information submitted in the June 1992 application for design certification be exempt from mandatory public disclo-j sure. While the staff has not completed its review of your request in i
accordance with the requirements of 10 CFR 2.790, that portion of the submit-ted information is being withheld from public disclosure pending the staff's 3-final determination. The staff concludes that these followon questions do not I
contain those portions of the information for which exemption is sought.
I However, the staff will withhold this letter from public disclosure for 30 calendar days from the date of this letter to allow Westinghouse the i
opportunity to verify the staff's conclusions.
If, after that time, you do not request that all or portions cf the information in the attachments be
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withheld from public disclosure in accordance with 10 CFR 2.790, this letter -
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will be placed in the NRC Public Document Room. -
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l These followon questions affect nine or fewer respondents, and'therefore are l
not subject to review by the Office of Management and Budget under P.L.96-511.
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If you have any questions regarding this matterf you can contact,me at j
i (301) 415-8548.
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Sincerely, l
original signed by:
l Diane T. Jackson, Project Manager Stantiardization Project Directorate l
Division of Reactor Program Management i
Office of Nuclear Reactor Regulation i
Docket No.52-003 r
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DISTRIBUTION: See next page i
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DATE 09/(6/96 0
09/;* MBT 09/IT/96 09/e/96 GOFFICIALRECORDCOPY i
Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 cc: Mr. B. A. McIntyre Mr. John C. Butler Advanced Plant Safety & Licensing Advanced Plant Safety & Licensing Westinghouse Electric Corporation Westinghouse Electric Corporation Energy Systems Business Unit Energy Systems Business Unit P.O. Box 355 Box 355 e
Pittsburgh, PA 15230 Pittsburgh, PA 15230 ' ;
f Mr. M. D. Beaumont Mr. S. M. Modro Nuclear and Advanced Technology Division Nuclear Systems Analysis Technologies Westinghouse Electric Corporation Lockheed Idaho Technologies Company One Montrose Metro Post Office Box 1625 '
11921 Rockville Pike Idaho Falls, ID 83415 Suite 350 Rockville, MD 20852 Letter to be distributed to the following addressees after the result of the propri-etary evaluation is received from Westinghouse.
Mr. Ronald Simard, Director Ms. Lynn Connor Advanced Reactor Programs DOC-Search Associates Nuclear Energy Institute Post Office Box 34 1776 Eye Street, N.W.
Cabin John, MD 20818 Suite 300 Washington, DC 20006-3706 Mr. Robert H. Buchholz GE Nuclear Energy Mr. James E. Quinn, Projects Manager 175 Curtner Avenue, MC-781 LMR and SBWR Programs San Jose, CA 95125 GE Nuclear Energy 175 Curtner Avenue, M/C 165 Mr. Sterling Franks San Jose, CA 95125 U.S. Department of Energy NE-50 Barton Z. Cowan, Esq.
19901 Germantown Road Eckert Seamans Cherin & Mellott Germantown, MD 20874 600 Grant Street 42nd Floor Pittsburgh, PA 15219 Mr. Charles Thompson, Nuclear Engineer AP600 Certification Mr. Frank A. Ross NE-50 U.S. Department of Energy, NE-42 19901 Germantown Road Office of LWR Safety and Technology Germantown, MD 20874 19901 Gennantown Road i
Germantown, MD 20874 Mr. Ed Rodwell, Manager PWR Design Certification Electric Power Research Institute 3412 Hillview Avenue Palo Alto, CA 94303
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4 DISTRIBUTION:
Letter to Nicholas J. Linarulo. Dated:
Seotember 23. 1996
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