ML060320725
| ML060320725 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/31/2006 |
| From: | Cowan P AmerGen Energy Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 5828-06-20386, GL-04-002 | |
| Download: ML060320725 (6) | |
Text
10 CFR 50.54(f) 5828-06-20386 January 31,2006 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Three Mile Island Nuclear Station, Unit 1 Facility Operating License No. DPR-50 NRC Docket No. 50-289
Subject:
Supplement to AmerGen Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors Relating to Downstream Effects Analyses
References:
(1)
Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, dated September 13, 2004 (2)
GSI-191 SE, Revision 0, Safety Evaluation of NEI Guidance of PWR Sump Performances, dated December 6,2004 (3)
Letter from P. B. Cowan (Exelon Generation Company, LLC and AmerGen Energy Company, LLC) to U. S. Nuclear Regulatory Commission Exelon/AmerGen Response to NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, dated September 1, 2005 The US. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2004-02 (Reference 1) on September 13,2004 to request that addressees perform an evaluation of the emergency core cooling system (ECCS) and containment spray system (CSS) recirculation functions in light of the information provided in the GL and, if appropriate, take additional actions to ensure system function.
The GL requested that by September 1, 2005, addressees provide information regarding confirmation that the ECCS and CSS recirculation functions under debris loading conditions are or will be in compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of the Generic Letter. AmerGen Energy Company, LLC (AmerGen) provided the response to the GL in reference (3).
US. Nuclear Regulatory Commission January 31,2006 Page 2 As part of the September 1,2005 GL response, AmerGen provided the NRC with schedule information relating to performance of Downstream Effects analyses. The initial Downstream Effects evaluation has been completed for TMI. During a Reactor Building walkdown, performed in accordance with NEI 02-01 "Condition Assessment Guidelines: Debris Sources Inside PWR Containments", TMI identified a greater amount of unqualified coatings and some additional insulation in the Reactor Building than was included in the debris generation evaluation. The debris generation and transport analyses, as well as the Downstream Effects analyses, will be revised to incorporate this additional information in the final screen design. provides supplemental information to the reference (3) GL response regarding the performance of the Downstream Effects analysis.
The additional scope associated with the Downstream Effects evaluation is not expected to impact AmerGen commitments that recirculation functions will be in compliance with the regulatory requirements listed in the subject Generic Letter by December 31, 2007.
If you have any questions or require additional information, please contact Mr. Doug Walker at (610) 765-5726.
I declare under penalty of perjury that the foregoing is true and correct.
Respectfully, Director - Licensing & Regulatory Affairs AmerGen Energy Company, LLC
Attachment:
- 1) Three Mile Island, Unit 1 Supplemental Information to the September 1, 2005 Generic Letter 2004-02 Response
- 2) List of Additional Commitments cc:
NRC Regional Administrator - NRC Region I NRC Project Manager, NRR - Three Mile Island Station NRC Senior Resident Inspector - Three Mile Island Station File No. 05049 Three Mile Island, Unit 1 Supplemental Information to the September 1,2005 Generic Letter 2004-02 Response Supplemental Information to the September 1,2005 Generic Letter 2004-02 Response Page 1 of 1 As part of the September 1,2005 GL response, AmerGen provided the NRC with schedule information relating to performance of Downstream Effects analyses. TMI has ident~fied additional scope required for completion of the Downstream Effects evaluation. The following information is provided to supplement TMl's September 1, 2005 response to GL 2004-02.
Downstream Effects Evaluation A Reactor Building walkdown was performed in accordance with the guidelines given in NEI 02-01 "Condition Assessment Guidelines: Debris Sources Inside PWR Containments" during TMl's 1 R16 Refueling Outage (completed November 2005). In general, the inspections confirmed the assumptions made in the debris generation calculations for latent debris and tags/labels located in containment. The inspection identified a greater amount of unqualified coatings and some additional insulation in the Reactor Building than was included in the debris generation evaluation. The debris generation and transport analyses will be revised to incorporate this additional information in the final screen design. Overall, the walkdown findings are not expected to significantly impact the final sump screen design as described in the September 1,2005, response.
The initial Downstream Effects evaluation has been completed for TMI. In addition to the components identified in the September 1, 2005 letter (LPI manual throttle valves, ECCS pump seals, cyclone separators, and seal flush systems), a potential concern for excessive wear of the HPI pumps was identified. Further evaluation of these components will be performed.
To support the final design of modifications required at TMI in response to GL 2004-02, a revision of the analyses will be performed. The revisions will incorporate the findings of the 1 R16 TMI RB walkdown, incorporate the final sump screen design, and include changes that will provide additional margin in the final design. The debris generation and transport calculations revisions are expected to be completed by the end of June 2006. The downstream effects evaluations will be revised based on the final debris transport calculation results and the final sump screen design and testing. In addition, the evaluation of downstream effects on the fuel will be reviewed to determine if a revision is required based on the revised debris analyses. To support the Fall 2007 strainer installation, the revised downstream effects analyses are expected to be completed in October 2006. At present, the scope of potential modifications is not expected to be significantly different than those described in the September 1, 2005 response.
TMI expects to be in compliance with the regulatory requirements listed in Generic Letter 2004-02 by December 31,2007.
Attach men t 2 Three Mile Island, Unit 1 List of Additional Commitments Three Mile Island, Unit 1 Commitments Page 1 of 1 COMMITMENT The following table identifies those actions to which AmerGen have committed in this document.
Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.
Scheduled Completion Date The revised downstream effects analyses will be complete by October 31,2006.
October 31,2006