WM 14-0026, 30-Day Response on Planned Actions to Restore Compliance Regarding Essential Service Water Design Issues

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30-Day Response on Planned Actions to Restore Compliance Regarding Essential Service Water Design Issues
ML14357A124
Person / Time
Site: Wolf Creek Wolf Creek Nuclear Operating Corporation icon.png
Issue date: 12/16/2014
From: Heflin A
Wolf Creek
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
WM 14-0026
Download: ML14357A124 (4)
v • d • e


Text

. 4' ,

WOLF CREEK NUCLEAR OPERATING CORPORATION Adam C. Heflin December 16, 2014 President, Chief Executive Officer and Chief Nuclear Officer WM 14-0026 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Reference:

1) Letter WM 14-0011, dated May 8, 2014, from A. C. Heflin, WCNOC, to USNRC
2) Letter WM 14-0013, dated May 8, 2014, from A. C. Heflin, WCNOC, to USNRC
3) Letter dated November 26, 2014, from T. W. Pruett, USNRC, to A. C.

Heflin, WCNOC

Subject:

Docket No. 50-482: 30-Day Response on Planned Actions to Restore Compliance Regarding Essential Service Water Design Issues Gentlemen:

In Reference 1, Wolf Creek Nuclear Operating Corporation (WCNOC) committed to install a modification to mitigate the adverse effects of column closure water hammer in the Essential Service Water (ESW) system prior to plant start-up from Refueling Outage (RF) 20, which is currently scheduled to start February 28, 2015.

In Reference 2, WCNOC committed to ensuring the reliability of the four containment coolers in the future by, in order of preference, either replacing the tube bundles with new based on material availability, inspection of the tube bundles, or testing of the existing tube bundles prior to startup from RF 20.

WCNOC is fully committed to meeting the commitments described in References 1 and 2.

Reference 3 requested a response within 30 days of the date of the letter to provide the following information in order to facilitate Nuclear Regulatory Commission (NRC) inspection planning to verify WCNOC's long-term actions have restored the system design and restored compliance with NRC requirements:

P.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831

-AoD (

An Equal Opportunity Employer M/F/HCNET

WM 14-0026 Page 2 of 2

1. The date when the design change documents and modification packages will be complete and available for inspection for the containment cooler replacement and water hammer mitigation modification.
2. The dates when post-modification testing for these modifications is expected to occur.
3. The dates when full compliance will be restored for the significant conditions adverse to quality associated with ESW system piping pitting corrosion, containment cooler pitting corrosion, and ESW system water hammer.

The Attachment to this letter contains the 30-day response to the requested information in Reference 3.

This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-4000, or Mr. Steven R. Koenig at (620) 364-4041.

Sincerely, Adam C. Heflin ACH/rlt Attachment cc: M. L. Dapas (NRC), w/a C. F. Lyon (NRC), w/a N. F. O'Keefe (NRC), w/a T. W. Pruett (NRC), w/a Senior Resident Inspector (NRC), w/a

Attachment to WM 14-0026 Page 1 of 2 30-Day Response on Planned Actions to Restore Compliance Regarding Essential Service Water Design Issues

1. The date when the design change documents and modification packages will be complete and available for inspection for the containment cooler replacement and water hammer mitigation modification.

WCNOC Response The date that the key design change documents and modification packages will be available for inspection for water hammer mitigation is February 2, 2015.

The date that the design change documents and modification packages will be available for inspection for the containment cooler replacement is March 2, 2015.

2. The dates when post-modification testing for these modifications is expected to occur.

WCNOC Response The currently scheduled start date for post-modification testing for water hammer mitigation is March 21, 2015.

The currently scheduled start date for post-modification testing for the containment coolers is March 19, 2015.

3. The dates when full compliance will be restored for the significant conditions adverse to quality associated with ESW system piping pitting corrosion, containment cooler pitting corrosion, and ESW system waterhammer.

WCNOC Response

1) ESW system piping pitting corrosion - We are currently in compliance with American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code requirements for ESW system piping wall-thickness and we have in place a monitoring and repair/replacement strategy to ensure continuing compliance.

In Refueling Outage (RF) 18, which began March 9, 2011, WCNOC began replacing above-ground ESW system piping and to date has replaced approximately 2,100 feet in total, which includes approximately 225 feet of ESW system piping in containment.

During RF 20 approximately 800 feet of ESW system piping is scheduled to be replaced. The remaining affected above-ground piping, prioritized based on risk significance, is planned to be replaced or inspected through RF 23 which is currently scheduled for Fall 2019. Additionally, WCNOC replaced 18,000 feet of below-ground ESW system piping during the Mid-Cycle 20 Outage.

As of May 8, 2014, more than 6,000 feet of the above-ground ESW system piping has been inspected using Guided Wave Technology.

2) Containment cooler pitting corrosion - Full compliance will be restored for the containment coolers with respect to pitting corrosion at the conclusion of RF 20. This compliance will occur following the replacement of all coils as well as the addition of

Attachment to WM 14-0026 Page 2 of 2 a preventive maintenance activity to complete recurring hydro-testing of those coils where design precludes non-destructive internal inspection. The "D" containment cooler will be replaced with a stainless steel design which allows for non-destructive internal inspection in RF 20.

The planned strategy also includes the replacement of the "B" containment cooler in RF 21, and "A" and "C" containment coolers in RF 22 with a stainless steel design which allows for non-destructive internal inspection. Based on the evaluation of necessary parameters, the two-cycle replacement strategy, combined with hydro-testing, is sufficient to restore full compliance for the containment coolers.

3) ESW system water hammer - Full compliance will be restored for the ESW system with respect to water hammer following successful completion of post-modification testing at the end of RF 20.

WCNOC has every intention of meeting the dates listed above. However, the dates are considered target dates and subject to change due to risks that may impact the schedule. The NRC will be notified if the documented dates will not be met.

. 4' ,

WOLF CREEK NUCLEAR OPERATING CORPORATION Adam C. Heflin December 16, 2014 President, Chief Executive Officer and Chief Nuclear Officer WM 14-0026 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Reference:

1) Letter WM 14-0011, dated May 8, 2014, from A. C. Heflin, WCNOC, to USNRC
2) Letter WM 14-0013, dated May 8, 2014, from A. C. Heflin, WCNOC, to USNRC
3) Letter dated November 26, 2014, from T. W. Pruett, USNRC, to A. C.

Heflin, WCNOC

Subject:

Docket No. 50-482: 30-Day Response on Planned Actions to Restore Compliance Regarding Essential Service Water Design Issues Gentlemen:

In Reference 1, Wolf Creek Nuclear Operating Corporation (WCNOC) committed to install a modification to mitigate the adverse effects of column closure water hammer in the Essential Service Water (ESW) system prior to plant start-up from Refueling Outage (RF) 20, which is currently scheduled to start February 28, 2015.

In Reference 2, WCNOC committed to ensuring the reliability of the four containment coolers in the future by, in order of preference, either replacing the tube bundles with new based on material availability, inspection of the tube bundles, or testing of the existing tube bundles prior to startup from RF 20.

WCNOC is fully committed to meeting the commitments described in References 1 and 2.

Reference 3 requested a response within 30 days of the date of the letter to provide the following information in order to facilitate Nuclear Regulatory Commission (NRC) inspection planning to verify WCNOC's long-term actions have restored the system design and restored compliance with NRC requirements:

P.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831

-AoD (

An Equal Opportunity Employer M/F/HCNET

WM 14-0026 Page 2 of 2

1. The date when the design change documents and modification packages will be complete and available for inspection for the containment cooler replacement and water hammer mitigation modification.
2. The dates when post-modification testing for these modifications is expected to occur.
3. The dates when full compliance will be restored for the significant conditions adverse to quality associated with ESW system piping pitting corrosion, containment cooler pitting corrosion, and ESW system water hammer.

The Attachment to this letter contains the 30-day response to the requested information in Reference 3.

This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-4000, or Mr. Steven R. Koenig at (620) 364-4041.

Sincerely, Adam C. Heflin ACH/rlt Attachment cc: M. L. Dapas (NRC), w/a C. F. Lyon (NRC), w/a N. F. O'Keefe (NRC), w/a T. W. Pruett (NRC), w/a Senior Resident Inspector (NRC), w/a

Attachment to WM 14-0026 Page 1 of 2 30-Day Response on Planned Actions to Restore Compliance Regarding Essential Service Water Design Issues

1. The date when the design change documents and modification packages will be complete and available for inspection for the containment cooler replacement and water hammer mitigation modification.

WCNOC Response The date that the key design change documents and modification packages will be available for inspection for water hammer mitigation is February 2, 2015.

The date that the design change documents and modification packages will be available for inspection for the containment cooler replacement is March 2, 2015.

2. The dates when post-modification testing for these modifications is expected to occur.

WCNOC Response The currently scheduled start date for post-modification testing for water hammer mitigation is March 21, 2015.

The currently scheduled start date for post-modification testing for the containment coolers is March 19, 2015.

3. The dates when full compliance will be restored for the significant conditions adverse to quality associated with ESW system piping pitting corrosion, containment cooler pitting corrosion, and ESW system waterhammer.

WCNOC Response

1) ESW system piping pitting corrosion - We are currently in compliance with American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code requirements for ESW system piping wall-thickness and we have in place a monitoring and repair/replacement strategy to ensure continuing compliance.

In Refueling Outage (RF) 18, which began March 9, 2011, WCNOC began replacing above-ground ESW system piping and to date has replaced approximately 2,100 feet in total, which includes approximately 225 feet of ESW system piping in containment.

During RF 20 approximately 800 feet of ESW system piping is scheduled to be replaced. The remaining affected above-ground piping, prioritized based on risk significance, is planned to be replaced or inspected through RF 23 which is currently scheduled for Fall 2019. Additionally, WCNOC replaced 18,000 feet of below-ground ESW system piping during the Mid-Cycle 20 Outage.

As of May 8, 2014, more than 6,000 feet of the above-ground ESW system piping has been inspected using Guided Wave Technology.

2) Containment cooler pitting corrosion - Full compliance will be restored for the containment coolers with respect to pitting corrosion at the conclusion of RF 20. This compliance will occur following the replacement of all coils as well as the addition of

Attachment to WM 14-0026 Page 2 of 2 a preventive maintenance activity to complete recurring hydro-testing of those coils where design precludes non-destructive internal inspection. The "D" containment cooler will be replaced with a stainless steel design which allows for non-destructive internal inspection in RF 20.

The planned strategy also includes the replacement of the "B" containment cooler in RF 21, and "A" and "C" containment coolers in RF 22 with a stainless steel design which allows for non-destructive internal inspection. Based on the evaluation of necessary parameters, the two-cycle replacement strategy, combined with hydro-testing, is sufficient to restore full compliance for the containment coolers.

3) ESW system water hammer - Full compliance will be restored for the ESW system with respect to water hammer following successful completion of post-modification testing at the end of RF 20.

WCNOC has every intention of meeting the dates listed above. However, the dates are considered target dates and subject to change due to risks that may impact the schedule. The NRC will be notified if the documented dates will not be met.

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