ML110400749
| ML110400749 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 01/14/2011 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Division of Operating Reactor Licensing |
| References | |
| Download: ML110400749 (3) | |
Text
1 WBN2Public Resource From:
Poole, Justin Sent:
Friday, January 14, 2011 9:04 AM To:
Crouch, William D Cc:
Hilmes, Steven A; WBN2HearingFile Resource
Subject:
Draft Open Item RAIs on Chapters 8 and 3.11 Attachments:
draft chapter 8 open items.docx
- 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.
JustinC.Poole ProjectManager NRR/DORL/LPWB U.S.NuclearRegulatoryCommission (301)4152048 email:Justin.Poole@nrc.gov
Hearing Identifier:
Watts_Bar_2_Operating_LA_Public Email Number:
253 Mail Envelope Properties (19D990B45D535548840D1118C451C74D7B646AE40E)
Subject:
Draft Open Item RAIs on Chapters 8 and 3.11 Sent Date:
1/14/2011 9:03:43 AM Received Date:
1/14/2011 9:03:46 AM From:
Poole, Justin Created By:
Justin.Poole@nrc.gov Recipients:
"Hilmes, Steven A" <sahilmes@tva.gov>
Tracking Status: None "WBN2HearingFile Resource" <WBN2HearingFile.Resource@nrc.gov>
Tracking Status: None "Crouch, William D" <wdcrouch@tva.gov>
Tracking Status: None Post Office:
HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 638 1/14/2011 9:03:46 AM draft chapter 8 open items.docx 20595 Options Priority:
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No Reply Requested:
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Recipients Received:
Resolve whether or not routine maintenance activities should result in increasing the EQ of the 6.9 kV motors to Category I status in accordance with 10 CFR 50.49. (Section 3.11.2.2.1).
TVA must clarify its use of the term equivalent (e.g., identical, similar) regarding the replacement terminal blocks to the NRC staff. If the blocks are similar, then a similarity analysis should be completed and presented to the NRC for review. (Section 3.11.2.2.1)
Resolve whether or not TVAs reasoning for not upgrading the MSIV solenoid valves to Category I is a sound reason to the contrary, as specified in 10 CFR 50.49(l). (Section 3.11.2.2.1)
The NRC staff requires supporting documentation from TVA to justify its establishment of a mild environment threshold for total integrated dose of less than 1x103 rads for electronic components such as semiconductors or electronic components containing organic material. (Section 3.11.2.2.1)
TVA should provide a summary of margin studies based on scenarios described in Section 8.1 for CSSTs A, B, C, and D. (Section 8.2.2)
TVA should provide to the NRC staff a detailed discussion showing that the load tap changer is able to maintain the 6.9 kV bus voltage control band given the normal and post-contingency transmission operating voltage band, bounding voltage drop on the grid, and plant conditions.
(Section 8.2.2)
TVA should provide the transmission system specifics (grid stability analyses) to the NRC staff.
In order to verify compliance with GDC 17, the results of the grid stability analyses must indicate that loss of the largest electric supply to the grid, loss of the largest load from the grid, loss of the most critical transmission line, or loss of both units themselves, will not cause grid instability.
(Section 8.2.2)
TVA should confirm that all other safety-related equipment (in addition to the Class 1E motors) will have adequate starting and running voltage at the most limiting safety related components (such as motor operated valves, contactors, solenoid valves or relays) at the degraded voltage relay setpoint dropout setting. TVA should also confirm that the final Technical Specifications are properly derived from these analytical values for the degraded voltage settings. (Section 8.3.1.2)
TVA should evaluate the re-sequencing of loads, with time delays involved, in the scenario of a LOCA followed by a delayed LOOP, and ensure that all loads will be sequenced within the time assumed in the accident analysis. (Section 8.3.1.11)
TVA should provide to the NRC staff the details of the administrative limits of EDG voltage and speed range, and the basis for its conclusion that the impact is negligible, and describe how it accounts for the administrative limits in the Technical Specification surveillance requirements for EDG voltage and frequency. (Section 8.3.1.14)