L-PI-08-028, Three-Month Response to GL 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems.

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Three-Month Response to GL 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems.
ML081020368
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 04/10/2008
From: Wadley M
Nuclear Management Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
GL-08-001, L-PI-08-028
Download: ML081020368 (2)
v • d • e


Text

Prairie Island Nuclear Generating Plant Operated by Nuclear Management Company, LLC L-PI-08-028 10 CFR 50.54(f)

U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 License Nos. DPR-42 and DPR-60 Three Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergencv Core Cooling, Decav Heat Removal, and Containment Sprav Svstems"

Reference:

1) NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated January 11, 2008.

The Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01 (Reference 1) to request that each licensee evaluate the licensing basis, design, testing, and corrective action program for the Emergency Core Cooling System (ECCS),

Residual Heat Removal (RHR) system, and Containment Spray system, to ensure that gas accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified. The NRC, in GL 2008-01, requested each licensee to submit a written response in accordance with 10 CFR 50.54(f) within 9 months.

Additionally, the NRC requested that if a licensee cannot meet the requested response date, the licensee "shall provide a response within 3 months of the date of this GL". In the 3 month response, the licensee was requested to describe the alternative course of action that it proposes to take, including the basis for the acceptability of the proposed alternative course of action.

The 2008 Prairie Island Unit 1 refueling outage (1R25) occurred earlier this year. In response to and using the guidance of GL 2008-01, NMC staff conducted walkdowns in Unit 1 containment during 1R25 and identified one vulnerability that has been entered into the corrective action program for resolution. Subsequent to the NMC walkdowns, the Nuclear Energy Institute (NEI) provided detailed guidance for responding to GL 2008-01. Subsequent to receiving the NEI guidance, NMC also received some operating experience from a similarly-designed plant that during ultrasonic examination 1717 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1121

Document Control Desk Page 2 (UT) conducted as part of their walkdown, a void in a horizontal stretch of RHR line was identified. The walkdown at Prairie Island did not include UT. Based on new NEI guidance and new operating experience from a similar plant, NMC believes it will be necessary to conduct additional Unit 1 walkdowns to fully respond to GL 2008-01.

Since these walkdowns will require the unit to be shutdown, NMC will require additional time to fully respond to GL 2008-01. As an alternative to the nine-month response, NMC proposes to complete detailed Unit 1 walkdowns during the next Unit 1 refueling outage (1R26) and completing GL 2008-01 evaluations within 90 days of completing 1R26.

This alternative course of action is considered acceptable based on current operating experience. Surveillance testing performed on the subject systems has confirmed that there are no currently identified gas voiding issues. In-service testing of the systems are routinely performed and has demonstrated acceptable performance. Also, the vulnerability that has been identified has been entered into the corrective action program for resolution.

Summaw of Commitments This letter contains two new commitments and no revisions to existing commitments:

1 Complete the detailed walkdowns of inaccessible sections of the Generic Letter 2008-01 subject systems prior to startup from the 2009 Unit 1 Refueling Outage.

2. Evaluations of the Generic Letter 2008-01 subject systems will be completed within 90 days following the completion of the Unit 1 2009 Refueling Outage.

I declare under penalty of perjury that the foregoing is true and correct. Executed on Michael D. Wadley Site Vice President, Prairie Isl Nuclear Generating Plant Nuclear Management cc: Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC

Text

Prairie Island Nuclear Generating Plant Operated by Nuclear Management Company, LLC L-PI-08-028 10 CFR 50.54(f)

U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 License Nos. DPR-42 and DPR-60 Three Month Response to NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergencv Core Cooling, Decav Heat Removal, and Containment Sprav Svstems"

Reference:

1) NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems" dated January 11, 2008.

The Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2008-01 (Reference 1) to request that each licensee evaluate the licensing basis, design, testing, and corrective action program for the Emergency Core Cooling System (ECCS),

Residual Heat Removal (RHR) system, and Containment Spray system, to ensure that gas accumulation is maintained less than the amount that challenges operability of these systems, and that appropriate action is taken when conditions adverse to quality are identified. The NRC, in GL 2008-01, requested each licensee to submit a written response in accordance with 10 CFR 50.54(f) within 9 months.

Additionally, the NRC requested that if a licensee cannot meet the requested response date, the licensee "shall provide a response within 3 months of the date of this GL". In the 3 month response, the licensee was requested to describe the alternative course of action that it proposes to take, including the basis for the acceptability of the proposed alternative course of action.

The 2008 Prairie Island Unit 1 refueling outage (1R25) occurred earlier this year. In response to and using the guidance of GL 2008-01, NMC staff conducted walkdowns in Unit 1 containment during 1R25 and identified one vulnerability that has been entered into the corrective action program for resolution. Subsequent to the NMC walkdowns, the Nuclear Energy Institute (NEI) provided detailed guidance for responding to GL 2008-01. Subsequent to receiving the NEI guidance, NMC also received some operating experience from a similarly-designed plant that during ultrasonic examination 1717 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1121

Document Control Desk Page 2 (UT) conducted as part of their walkdown, a void in a horizontal stretch of RHR line was identified. The walkdown at Prairie Island did not include UT. Based on new NEI guidance and new operating experience from a similar plant, NMC believes it will be necessary to conduct additional Unit 1 walkdowns to fully respond to GL 2008-01.

Since these walkdowns will require the unit to be shutdown, NMC will require additional time to fully respond to GL 2008-01. As an alternative to the nine-month response, NMC proposes to complete detailed Unit 1 walkdowns during the next Unit 1 refueling outage (1R26) and completing GL 2008-01 evaluations within 90 days of completing 1R26.

This alternative course of action is considered acceptable based on current operating experience. Surveillance testing performed on the subject systems has confirmed that there are no currently identified gas voiding issues. In-service testing of the systems are routinely performed and has demonstrated acceptable performance. Also, the vulnerability that has been identified has been entered into the corrective action program for resolution.

Summaw of Commitments This letter contains two new commitments and no revisions to existing commitments:

1 Complete the detailed walkdowns of inaccessible sections of the Generic Letter 2008-01 subject systems prior to startup from the 2009 Unit 1 Refueling Outage.

2. Evaluations of the Generic Letter 2008-01 subject systems will be completed within 90 days following the completion of the Unit 1 2009 Refueling Outage.

I declare under penalty of perjury that the foregoing is true and correct. Executed on Michael D. Wadley Site Vice President, Prairie Isl Nuclear Generating Plant Nuclear Management cc: Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC

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