ML092860079
| ML092860079 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 10/13/2009 |
| From: | Thadani M Plant Licensing Branch IV |
| To: | Harrison A South Texas |
| Thadani, M C, NRR/DORL/LP4, 415-1476 | |
| References | |
| GL-08-001, TAC MD7881, TAC MD7882 | |
| Download: ML092860079 (4) | |
Text
From:
Thadani, Mohan Sent:
Tuesday, October 13, 2009 7:19 AM To:
Harrison, Albon Cc:
Cranston, Gregory
Subject:
G L 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal,, and Containment Spray Systems."
By letters dated October 13, 2008, and January 22, 2009, (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML082960430 and ML090330142 respectively), STP Nuclear Operating Company, the licensee for the South Texas Project (STP),
Units 1 and 2, provided Nuclear Regulatory Commission (NRC) responses to Generic Letter (GL) 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems."
The NRC staff has reviewed the licensee's responses, and concluded that additional information is needed to conclude that the licensee has acceptably demonstrated that the subject systems are in compliance with the current licensing and design bases and applicable regulatory requirements, and that suitable design, operational, and testing control measures are in place for maintaining this compliance as required in GL 2008-01. The NRC staff's request for additional information (RAI) is outlined below.
Please provide your response to this RAI in 45 calendar days from the date of this email.
Thanks.
Mohan C Thadani Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation (301) 415-1476 Mohan.Thadani@nrc.gov REQUEST FOR ADDITIONAL INFORMATION (RAI)
- 1. STP will evaluate the resolution of TS issues with respect to the changes contained in the Technical Specifications Task Force traveler to determine applicability and further assess any changes to the TS and TS Bases (Reference 4). Clarify the schedule for evaluating the TSTF traveler, and submitting a license amendment, if it is necessary to submit a license amendment as a result of the evaluation of the TSTF traveler.
- 2. In Reference 4 the licensee states that if voids are found during periodic venting, the procedure requires that the Shift Supervisor be notified and a condition report would be
written in accordance with the Corrective Action program. Clarify how the condition is determined, including any criteria used. Discuss follow-up actions, such as quantifying the size of the void, and trending the volume of the void.
- 3. Clarify the meaning of accessible and normally inaccessible as used in references 4 and 5. Include discussion of piping within containment; piping that requires scaffolding to reach; and piping in posted radiation areas.
- 4. Water level setpoints along with system design features are designed to prevent vortex effects that otherwise could potentially ingest gas into the GL systems during design basis events (Reference 4). Since flow rates under realistic accident conditions (non-degraded pumps, three trains running) may significantly exceed the design basis accident flow rates, clarify how the stated conclusions are applicable to actual expected accident conditions in all modes of operation.
- 5. The licensee states in Reference 4 that time delays estimated for delivery of flow for the various ECCS functions are based on pump start times and valve opening times. No additional allowance for the effects of gas accumulation is included in the calculations.
Justify that the use of conservative delays due to pump start and valve actuation is enough to bound the effect of gas accumulation in the subject systems.
- 6. Training was not identified in the GL (Reference 3) but is considered to be a necessary part of applying procedures and other activities when addressing the issues identified in the GL as the licensee has recognized. Provide a brief description of training REFERENCES 1 Preliminary Assessment of Responses to Generic Letter 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems, and Future NRC Staff Review Plans. Letter from Ruland, William H.,
Nuclear Regulatory Commission to James H. Riley, Nuclear Energy Institute, May 28, 2009. ML091390637 2 Generic Letter 2008-01 Response Guidance Generic Letter (GL) 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Contain Spray Systems. Evaluation and 3 Month Response Template, Enclosure 2, Generic Letter 2008-01 Response Guidance. Letter from James H. Riley, Director of Engineering, Nuclear Generation Division, Nuclear Energy Institute, to Administrative Points of Contact. March 20, 2008.
3 NRC Generic Letter 2008-01: Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems, Letter from Michael J.
Case, Director, Division of Policy and Rulemaking, Office of Nuclear Reactor Regulation, Nuclear Regulatory Commission. January 11, 2008. ML072910759,
4 South Texas Project, Units 1 and 2, Docket No. STN 50-498, STN 50-499, Nine-Month Response to NRC Generic Letter 2008-01, Letter from G.T. Powell, Vice President, Engineering, STP Nuclear Operating Company, to Document Control Desk, Nuclear Regulatory Commission., dated October 13, 2008. ML082960430, 5 Sorensen, Joel P., Texas Project, Units 1 and 2, Docket No. STN 50-498, STN 50-499, Nine-Month Supplemental Response to Generic Letter 2008-01, Letter to Document Control Desk, NRC, from Vice President, Engineering, STP Nuclear Operating Company, ML090330142, January 22, 2009.
6 Warren C. Lyon, U.S. Nuclear Regulatory Commission, Revision 2 to NRC Staff Criteria for Gas Movement in Suction Lines and Pump Response to Gas, ML090900136, March 26, 2009.
E-mail Properties Mail Envelope Properties ()
Subject:
G L 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal,, and Containment Spray Systems."
Sent Date: 10/9/2009 11:02:46 AM Received Date: 10/13/2009 7:18:00 AM From: Thadani, Mohan Created By: Mohan.Thadani@nrc.gov Recipients:
awharrison@STPEGS.COM (Harrison, Albon)
Tracking Status: None Gregory.Cranston@nrc.gov (Cranston, Gregory)
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 13508 10/9/2009 Options Expiration Date:
Priority: olImportanceNormal ReplyRequested: False Return Notification: False
Sensitivity: olNormal Recipients received: