ML101610692
| ML101610692 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 06/08/2010 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Division of Operating Reactor Licensing |
| References | |
| Download: ML101610692 (4) | |
Text
WBN2Public Resource From: Lamb, John Sent: Tuesday, June 08, 2010 9:32 AM To: Arent, Gordon; wdcrouch@tva.gov Cc: WBN2HearingFile Resource; Wiebe, Joel; Raghavan, Rags; Milano, Patrick; Haag, Robert
Subject:
For Your Review - Watts Bar Unit 2 - EQVB Preliminary RAIs Attachments: EQVB Prelim RAI's-Chapter 14 2 1.docx Gordon & Bill, Attached, for your review, are preliminary Request for Additional Information (RAI) questions regarding Watts Bar Nuclear Plant (WBN), Unit 2. Please review to ensure that the RAI questions are understandable, the regulatory basis is clear, there is no proprietary information contained in the RAI, and to determine if the information was previously docketed. Please also let me know how much time Tennessee Valley Authority (TVA) needs to respond to the RAI questions.
Thanks.
John 1
Hearing Identifier: Watts_Bar_2_Operating_LA_Public Email Number: 23 Mail Envelope Properties (BE1CC4A72435624D84F8699734202B3E1FABE65AEA)
Subject:
For Your Review - Watts Bar Unit 2 - EQVB Preliminary RAIs Sent Date: 6/8/2010 9:31:31 AM Received Date: 6/8/2010 9:31:35 AM From: Lamb, John Created By: John.Lamb@nrc.gov Recipients:
"WBN2HearingFile Resource" <WBN2HearingFile.Resource@nrc.gov>
Tracking Status: None "Wiebe, Joel" <Joel.Wiebe@nrc.gov>
Tracking Status: None "Raghavan, Rags" <Rags.Raghavan@nrc.gov>
Tracking Status: None "Milano, Patrick" <Patrick.Milano@nrc.gov>
Tracking Status: None "Haag, Robert" <Robert.Haag@nrc.gov>
Tracking Status: None "Arent, Gordon" <garent@tva.gov>
Tracking Status: None "wdcrouch@tva.gov" <wdcrouch@tva.gov>
Tracking Status: None Post Office: HQCLSTR01.nrc.gov Files Size Date & Time MESSAGE 528 6/8/2010 9:31:35 AM EQVB Prelim RAI's-Chapter 14 2 1.docx 20646 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:
Recipients Received:
PRELIMINARY REQUEST FOR ADDITIONAL INFORMATION FOR WATTS BAR NUCLEAR PLANT, UNIT 2 TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-391 Below, for your review, are preliminary Request for Additional Information (RAI) questions regarding Watts Bar Nuclear Plant (WBN), Unit 2. Please review to ensure that the RAI questions are understandable, the regulatory basis is clear, there is no proprietary information contained in the RAI, and to determine if the information was previously docketed. Please also let me know how much time Tennessee Valley Authority (TVA) needs to respond to the RAI questions.
By letter dated January 11, 2010 (Agencywide Documents Access and Management System Accession No. ML100191686), TVA submitted Final Safety Analysis Report (FSAR)
Amendment No. 97 for WBN Unit 2. The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the TVA in FSAR Amendment No. 97.
Quality and Vendor Branch RAIs for FSAR Section 14.2
- 1. FSAR Chapter 14, Table 14.2-1, Sheet 48 of 90, "[Alternating Current] AC Power Distribution System Test Summary," TVA deleted the requirement to verify item 5 Demonstrate manual and automatic transfer schemes operate in accordance with design drawings under "Test Method." The NRC staff did not find a basis or justification for deletion of this test. The NRC staff requests TVA to provide a basis or justification why this test is not required for start of WBN Unit 2 to demonstrate the capability of the manual and automatic transfer schemes for the AC power distribution system for dual unit operation. Also, provide a description of the transfer scheme to include whether running loads are shed and then re-sequenced on, or if the loads are block loaded. If TVA is taking credit for the Technical Specification (TS) Surveillance Requirement (SR) 3.8.1.8 currently performed for WBN Unit 1 every 18 months for deleting this test requirement then describe how the loads of WBN Unit 2 are included in this surveillance.
- 2. FSAR Chapter 14, Table 14.2-1, Sheet 48 of 90, "AC Power Distribution System Test Summary," TVA revised Item 7 (renumbered item 6) to state that it will verify the capability of each common station service transformer (CSST) to carry the load required to supply engineered safety feature (ESF) loads for its respective load group under WBN Unit 2 loss-of-coolant accident (LOCA) conditions. The NRC staff finds this commitment to be different than the staffs acceptance documented in the Supplements 14 and 16 to the NUREG -0847, Safety Evaluation Report Related to the Operation of Watts Bar Nuclear Plant Units 1 and 2. In Supplement 16 to NUREG-0847, the NRC staff accepted TVAs position to demonstrate the capability of each CSST to carry the load required to supply ESF loads on one unit (WBN Unit 1) under LOCA condition since TVA, at that time, was not seeking an operating license for WBN Unit 2. The NRC staff documented its acceptance of TVAs position based on the commitment that before issuance of an Operating License for WBN Unit 2, TVA would
have to demonstrate the capability of each CSST to carry the load required to supply ESF loads of one unit (WBN Unit 2) under LOCA conditions in addition to power required for shutting down the non-accident unit (WBN Unit 1). Therefore, the NRC staff requests that TVA revise its test commitment to verify the capability of each CSST with LOCA conditions in WBN Unit 2 in addition to power required for normal shutdown (non-accident loads) of WBN Unit 1, or provide an explanation and justification why the original commitment was revised.
- 3. FSAR Chapter 14, Table 14.2-1, Sheet 49 of 90, "AC Power Distribution System Test Summary," TVA deleted the requirement to verify item 2 under Acceptance Criteria. The NRC staff did not find a basis or justification for deletion of this test. The NRC staff requests TVA to provide a justification why this test is not required for start of WBN Unit 2. TVA should describe how the loads of WBN Unit 2 are addressed with respect to the capability of the manual and automatic transfer schemes for the AC power distribution system between onsite (standby) diesels units from normal or alternate supply for dual-unit operation.
- 4. FSAR Chapter 14, Table 14.2-1, Sheet 44 of 89, "Diesel Generator Test Summary," TVA deleted the requirements to verify items 1 through 5 under Test Method. The NRC staff did not find a basis or justification for deletion of these tests. The NRC staff requests TVA to provide a justification why these tests are not required for start of WBN Unit 2. If these tests are currently being performed under the WBN Unit 1 TS SRs, then provide a summary of the impact on these tests for the WBN Unit 2 diesel generators due to dual-unit operation. Also, identify the WBN Unit 1 TS surveillances that are currently being performed to accomplish these tests.
- 5. FSAR Chapter 14, Table 14.2-1, Sheet 45 of 89, "Diesel Generator Test Summary," TVA deleted the requirement to verify items 10 under Test Method. If this test is currently performed on WBN Unit 2 diesel generators under the WBN Unit 1 TS SR 3.8.1.14 requirements, then confirm that the WBN Unit 1 TS SR 3.8.1.14 accomplishes this test.
Also, confirm that this surveillance performed for verifying WBN Unit 2 diesel generator capacity envelops the design-basis accident (DBA) loads of WBN Unit 2 plus the power required for the WBN Unit 1 loads.
- 6. The FSAR Table 14.2-1, Chapter 14 (Sheets 44 and 45 of 89), "Diesel Generator Test Summary," does not list a test that the WBN Unit 2 diesel generators automatic trip are bypassed on automatic or emergency start signal except for engine over speed and generator differential current. The NRC staff requests TVA to provide a justification why this test is not required for start of WBN Unit 2. If this test is currently performed on WBN Unit 2 diesel generators under the WBN Unit 1 TS SRs, then identify the WBN Unit 1 TS SR that accomplishes this test.