ML110680045
| ML110680045 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/09/2011 |
| From: | Orf T Plant Licensing Branch II |
| To: | Wasik C Florida Power & Light Co |
| Orf, T J, NRR/DORL/301-415-2788 | |
| References | |
| Download: ML110680045 (2) | |
Text
From:
Orf, Tracy Sent:
Wednesday, March 09, 2011 8:19 AM To:
'Wasik, Chris'
Subject:
St. Lucie Unit 1 EPU - request for additional information (Performance and Testing)
Dear Mr. Wasik,
By letter dated November 22, 2010 (Agencywide Documents Access and Management System Accession No. ML103560415) Florida Power & Light Company (the licensee) submitted a license amendment request for St. Lucie Unit 1.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the licensee's submittal and has concluded that additional information is required from the licensee in order for the NRC staff to complete their review. The questions below describe these requests for additional information (RAls).
The NRC requests that the licensee respond to these RAls within 30 days of the date of this e-mail. If the licensee concludes that more than 30 days are required to respond to the RAls, the licensee should request additional time, including a basis for why the extension is needed.
Please contact me at the number below or by e-mail if you have any questions on this issue or if you require additional time to submit your responses.
Sincerely, Tracy J. Orf, Project Manager St. Lucie Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Phone: (301) 415-2788 CPTB-1:
On page 2.2.4-14, it is stated:
As addressed under Topic 10 below, for the MSIV [Main Steam Isolation Valve] safety-related close stroke, the maximum expected differential pressure is increasing for EPU beyond the value used in the current valve/actuator capability analysis. However, the closing margin (percentage of actuator output greater than that required to stroke the valve) for the MSIVs remains adequate for the safety-related close stroke at EPU conditions. The MSIVs are designed to use flow to assist in closure and, therefore the increased steam flow under EPU conditions will enhance the closing of the valve, thus ensuring that the TS [Technical Specification] requirements for closing time ( 6 seconds) are met.
Please provide the value for the maximum expected differential pressure at EPU conditions since Table 2.2.4-2 does not provide this value. Additionally, please provide the closing margins for the MSIVs at the current and EPU conditions.
CPTB-2:
On page 2.2.4-14, it is stated:
As discussed in LR [Licensing Report] Section 2.5.5.1, modification of the MSIVs is required to improve the structural integrity and fatigue life of the valves in the event of a spurious closure at EPU conditions.
This modification does not affect the safety-related function of the valves to close under accident conditions.
On page 2.5.5.1-8, the only discussion provided is:
The MSIVs will be modified to improve structural integrity and fatigue life in the event of spurious closure at EPU conditions.
Please describe the modifications to the MSIVs in greater detail and explain why the modifications do not affect the safety-related functions of the valves to close under accident conditions.
CPTB-3:
On page 2.2.4-16, it is stated:
As discussed under Topic 10 below, for the SGBS [Steam Generator Blowdown System] containment isolation valve safety-related close stroke, the maximum expected differential pressure is increasing for EPU beyond the value used in the current valve/actuator capability analysis. However, the closing margin for the SGBS containment isolation valves remains adequate for the safety-related close stroke at EPU conditions.
Please provide the value for the maximum expected differential pressure at EPU conditions since Table 2.2.4-2 does not provide this value. Additionally, please provide the closing margin at the current and EPU conditions for the SGBS containment isolation valves and explain why the closing margin at EPU conditions remains adequate.