TSTF-07-13, Response to NRC Request for Additional Information (RAI) Regarding TSTF-495, Revision 0, Bases Change to Address GE Part 21 SC05-03, Dated January 11, 2007
| ML070960090 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 04/04/2007 |
| From: | Gambrell R, Joseph Messina, Millar D, Yates B BWR Owners Group, PWR Owners Group, Technical Specifications Task Force |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TSTF-07-13 | |
| Download: ML070960090 (2) | |
Text
TECHNICAL SPECIFICATIONS TASK FORCE A JOINT OWNERS GROUP ACTIVITY TSTF April 4, 2007 TSTF-07-13 PROJ0753 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Response to NRC "Request for Additional Information (RAI) Regarding TSTF-495, Revision 0, 'Bases Change to Address GE Part 21 SC05-03'," dated January 11, 2007
REFERENCE:
Letter from T. J. Kobetz (NRC) to the Technical Specifications Task Force, "Request for Additional Information (RAI) Regarding TSTF-495, Rev. 0,
'Bases Change to Address GE Part 21 SC05-03'," dated January 11, 2007.
Dear Sir or Madam:
In the referenced letter, the NRC provided a Request for Additional Information (RAI) regarding TSTF-495, Revision 0, "Bases Change to Address GE Part 21 SC05-03." This letter responds to the NRC's referenced request.
Any NRC review fees associated with the review of TSTF-495 should continue to be billed to the Boiling Water Reactors Owners Group.
The TSTF requests that the Traveler be made available under the Consolidated Line Item Improvement Process.
Should you have any questions, please do not hesitate to contact us.
Bert Yates (PWROG/W)
John Messina (BWROG)
Dana Millar (PWROG/CE)
Reene' Gambrell (PWROG/B&W)
Enclosure cc:
Tim Kobetz, Technical Specifications Branch, NRC Ross Telson, Technical Specifications Branch, NRC 11921 Rockville Pike, Suite 100, Rockville, MD 20852 Phone: 301-984-4400, Fax: 301-984-7600 Email: tstf@excelservices.com Administered by EXCEL Services Corporation
Response to NRC Request for Additional Information Regarding TSTF-495, Revision 0, "Bases Change to Address GE Part 21 SC05-03,"
dated January 11, 2007 NRC RAI Provide the results of additional analyses or studies performed that were conducted using a set of plant parameters not reported in the March 2005 Part 21 which gave results indicating that the limits in Figure 1 (Reference MFN 05-21) would be exceeded, or provide justification why additional analyses should not be performed.
(Note that this RAI was clarified in a conference call with NRC on February 8, 2007.)
RESPONSE
As part of the original evaluation, all Final Safety Analysis Report Anticipated Operational Occurrence (AOO) events that may result in a decrease in steam dome pressure were reviewed to determine if they could result in the steam dome pressure dropping below the Safety Limit (785 psig). The only event that is capable of a significant vessel depressurization that could cause steam dome pressure to decrease below 785 psig is the Pressure Regulator Failure - Maximum Demand Open event.
There are other analyzed events that may result in minor depressurization (for example, the Inadvertent Safety/Relief Valve Opening event and the Inadvertent HPCI/HPCS/RCIC Pump Startup event, which cause vessel depressurizations on the order of 10 to 15 psi), but the analysis of these events assumes that the pressure regulator is functioning. The pressure regulator senses the nuclear steam system pressure decrease and within a few seconds closes the turbine control valves far enough to stabilize the steam dome pressure at a slightly lower value. Therefore, the Pressure Regulator Failure - Maximum Demand Open event is the only event that could lead to a steam dome pressure drop to below 785 psig while thermal power is above ~25% of Rated Thermal Power.
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