OWestinghouse. U.S. Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, D.C February 1, 2010

Transcription

1 OWestinghouse Westinghouse Electric Company Nuclear Power Plants P.O. Box 355 Pittsburgh, Pennsylvania USA U.S. Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, D.C Direct tel: Direct fax: sisklrb@westinghouse.com Your ref: Docket No Our ref: DCPNRC_ Subject: AP1000 Response to Proposed Open Item (Chapter 8) Westinghouse is submitting the following responses to the NRC open item (01) on Chapter 8. These proposed open item response are submitted in support of the AP 1000 Design Certification Amendment Application (Docket No ). The information included in these responses is generic and is expected to apply to all COL applications referencing the AP 1000 Design Certification and the AP 1000 Design Certification Amendment Application. Enclosure 1 provides the response for the following proposed Open Item(s): Questions or requests for additional information related to the content and preparation of this response should be directed to Westinghouse. Please send copies of such questions or requests to the prospective applicants for combined licenses referencing the AP1000 Design Certification. A representative for each applicant is included on the cc: list of this letter. Very truly yours, Robert Sisk, Manager Licensing and Customer Interface Regulatory Affairs and Standardization /Enclosure 1. Response to Proposed Open Item (Chapter 8) 04141jb.doc NJ

2 DCP NRC Page 2 of 2 cc: D. Jaffe E. McKenna T. Spink P. Hastings R. Kitchen A. Monroe P. Jacobs C. Pierce E. Schmiech G. Zinke R. Grumbir B. Seelman - U.S. NRC - U.S. NRC - TVA - Duke Power - Progress Energy - SCANA - Florida Power & Light - Southern Company - Westinghouse - NuStart/Entergy - NuStart - Westinghouse 04141jb.doc

3 DCP NRC ENCLOSURE 1 AP1000 Response to Proposed Open Item (Chapter 8) 0414ijb.doc

4 AP1000 TECHNICAL REPORT REVIEW Response to Request For Additional lnformation (RAG) RAI Response Number: Revision: 0 Question: In RAI-SRP8.3.2-EEB-08, the NRC staff stated that Figure , Tier 1 of the DCD shows that the motor control centers that feed the safety-related 250 Vdc battery chargers are fed from 480 V load centers. The applicant was asked to provide a detailed drawing of the 480 V load centers, the MCC that feed the battery chargers and the dc motor control center showing typical loads powered from these buses. The applicant was asked to describe how the 480 V load centers are protected from degraded voltage and frequency conditions and to provide the following information: a. The results of an analysis of the onsite power distribution system to demonstrate that adequate voltages at terminal of the battery chargers are optimized for the maximum and minimum voltage variations of the offsite power for events, such as a unit trip, loss-of-coolant accident, startup or shutdown. b. A description of the analytical techniques, methodology, and assumptions used in performing the analyses. Also, provide the results of these analyses for each level of onsite electrical power distribution. c. Identification of the analytical software (and its version) used for performing these studies and make available to the NRC staff an electronic copy of the electrical distribution system model that forms the basis of the analytical studies. Information by the applicant. In general, the NRC staff is seeking understanding of the applicant's approach to assuring consistency in the transfer to the Combined Operating License (COL) applicant the 1) analysis, calculations and assumptions made for maintaining adequate voltage regulation at safety-related equipment terminals, 2) the analysis and assumptions used to evaluate acceptable rating for equipment such as circuit breakers, 3) the studies, acceptance criteria, and assumptions used to determine equipment sizing. This is Open Item OI-SRP EEB-08. Westinghouse Response: Westinghouse will supply a COL Applicant with a configuration controlled model developed through the use of Electrical Transient Analyses Program TM. The Program will include the nonsafety related AC design calculations, including design inputs, assumptions, methodologies, and acceptance criteria used in the development of the sizing basis, settings, load flow, short circuit and voltage regulation. The results of the analysis of the onsite power distribution system will demonstrate that adequate voltages at terminal of the battery chargers are optimized for the 01-SRP8.3.2-EEB-08 I WestinghousePae1o2

5 AP1000 TECHNICAL REPORT REVIEW Response to Request For Additional lnformation (RAI) maximum and minimum voltage variations of the offsite power for events, such as a unit trip, loss-of-coolant accident, startup or shutdown. The battery charger function is to provide isolation between input ac and the dc system and to provide dc power when ac power is available. Safe shutdown of the plant does not require the support of the battery chargers. (DCD rev 16, paragraph 3, paragraph 7, table item 1, table item 1). As such, if the input voltage/frequency to the battery chargers falls outside of the acceptable limits defined in the detailed component design the chargers will perform their required function of isolation and the batteries will support those safety related loads requiring class le power. Additionally, Westinghouse will provide analyses of the safety related distribution system that will include load flow, voltage profile, short circuit analysis. These calculations will include techniques, methodology, and assumptions used in performing the analyses. These safety DC system calculations will be performed demonstrating the ability of the battery to support the assigned safety related function of the system. This DC analysis information is also addressed in Ol-SRP8.3.2-EEB-03 and OI-SRP8.3.2-EEB-05. Reference(s): Design Control Document (DCD) Revision: PRA Revision: Technical Report (TR) Revision: OWestinghouse Page 2 of 2