NLS2014014, Response to Request for Additional Information Regarding Bulletin 2012-01

Response to Request for Additional Information Regarding Bulletin 2012-01

ML14038A120
Person / Time
Site:	Cooper
Issue date:	02/03/2014
From:	Limpias O Nebraska Public Power District (NPPD)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL-12-001, NLS2014014
Download: ML14038A120 (5)

Text

H Nebraska Public Power District Always there when you need us NLS2014014 February 3, 2014 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Subject:

Response to Request for Additional Information Regarding Bulletin 2012-01 Cooper Nuclear Station, Docket No. 50-298, DPR-46

Reference:

1. Letter from Michele G. Evans, U.S. Nuclear Regulatory Commission, to List of Addressees, including Oscar A. Limpias, Nebraska Public Power District, dated December 20, 2013, "Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System""

2. Letter from Brian J. O'Grady, Nebraska Public Power District, to U.S. Nuclear Regulatory Commission, dated October 24, 2012, "90-Day Response to NRC Bulletin 2012-01, Design Vulnerability in Electric Power System" (NLS2012081)

3. NRC Bulletin 2012-01, "Design Vulnerability in Electric Power System,"

dated July 27, 2012 (Accession No. ML12074A115)

Dear Sir or Madam:

The purpose of this letter is for Nebraska Public Power District (NPPD) to submit its response (Attachment 1) to the Nuclear Regulatory Commission (NRC) Request for Additional Information (Reference 1) for the Cooper Nuclear Station (CNS). This submittal is in addition to the NPPD submittal provided (Reference 2) in response to NRC Bulletin 2012-01 (Reference 3).

This letter contains a regulatory commitment. The commitment is described in Attachment 2 to this letter.

If you have any questions concerning this matter, please contact David W. Van Der Kamp, Licensing Manager, at (402) 825-2904.

COOPER NUCLEAR STATION P.O. Box 98 / Brownville, NE 68321-0098 Telephone: (402) 825-3877 / Fax: (402) 825-5211 www.nppd.com

NLS2014014 Page 2 of 2 I declare under penalty of perjury that the forgoing is true and correct.

Executed on: 04 //----

(Date Sinc elyIy Asc ýA. Limpli2 Vice President- uclear and Chief Nuclear Officer

/dm Attachments: 1. NPPD Response to Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System"

2. List of Regulatory Commitments cc: Regional Administrator w/attachments USNRC - Region IV Cooper Project Manager w/attachments USNRC - NRR Project Directorate IV- 1 Senior Resident Inspector w/attachments USNRC - CNS NPG Distribution w/attachments CNS Records w/attachments

NLS2014014 Attachment I Page 1 of 2 Attachment 1 Nebraska Public Power District Response to Request for Additional Information to Bulletin 2012-01, "Design Vulnerability in Electric Power Systems" The Nuclear Regulatory Commission (NRC) Request for Additional Information for Bulletin 2012-01 is shown in italics. The Nebraska Public Power District (NPPD) responses to the individual questions for Cooper Nuclear Station are shown in block font.

NRC letter (ADAMS ML13351A314) dated December 20, 2013 requests thefollowing:

"In orderfor the NRC staff to complete its review of responses to the bulletin, the following additionalinformation is requested:

1. Provide a summary ofall interim corrective actions that have been taken since the January30, 2012, event at Byron Station, Unit 2, to ensure thatplant operatorscan promptly diagnose and respond to open phase conditions on the offsite power circuitsfor Class-lE vital buses until permanent correctiveactions are completed.

NPPD Response Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at Cooper Nuclear Station. Based the plant's offsite power configuration, electrical design details, and on lessons learned, the following actions were taken to ensure plant operators can promptly diagnose and respond to open phase conditions (OPC):

• Interim Corrective Actions o Daily walk-downs are on-going of the switchyards to identify any potential conditions that could cause an OPC.

o Transformer yard rounds are performed daily and include general and detailed inspections of the transformers and inspection of external wiring and connections to identify any potential conditions that could cause an OPC.

o Operations procedures were revised to include recording all three phase voltages for each offsite power source at least once per shift.

NLS2014014 Attachment I Page 2 of 2

2. Provide a status and schedulefor completion ofplant design changes and modifications to resolve issues with an open phase of electricpower.

NPPD Response

• Status o Cooper Nuclear Station is investigating options being researched by several vendors (PSC2000, EPRI, Schweitzer, etc.) to detect OPC faults. There is currently no generic, off-the-shelf technology that has been proven to detect all the required open phase fault conditions for all plant and transformer designs.

o Cooper Nuclear Station is fully engaged in the development of the Nuclear Energy Institute (NEI) OPC Guidance Document, as well as development of enhancements to software tools being used to

/ analyze OPC faults.

o With the goal of ensuring accurate detection without compromising nuclear safety or increasing plant risk, this new OPC technology is being thoroughly evaluated, will be tested, and will be fully analyzed before installation.

o Vulnerability studies of the OPC faults have been started for Cooper Nuclear Station.

Schedule o Cooper Nuclear Station has committed to the generic schedule provided in the Industry OPC Initiative.

o It is our intention to meet the milestones of this schedule; however, deviations may be required to accommodate outage schedules, software and hardware availability, manufacturer's delivery capabilities, licensing delays, etc.

o Any deviation from the Industry OPC Initiative schedule will be documented through the deviation/exemption process addressed in the NEI OPC Guidance Document.

NLS2014014 Page 1 of I LIST OF REGULATORY COMMITMENTS The following table identifies those actions committed to by Nebraska Public Power District in this document. Any other actions discussed in this submittal are provided for information purposes and are not considered to be regulatory commitments.

TYPE (Check one) SCHEDULED COMMITMENT/COMMITMENT NO. ONE-TIME CONTINUING COMPLETION ACTION COMPLIANCE DATE Cooper Nuclear Station will follow the In accordance generic schedule provided in the Industry with the schedule Open Phase Conditions (OPC) Initiative. provided in the Any deviation from the Industry OPC Industry OPC Initiative schedule will be documented Initiative.

through the deviation/exemption process addressed in the NEI OPC Guidance Document. / NLS2014014-01

+ 4 4 EN-LI-106 Rev. 9C0, Attachment 9.3

Text

H Nebraska Public Power District Always there when you need us NLS2014014 February 3, 2014 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001

Subject:

Response to Request for Additional Information Regarding Bulletin 2012-01 Cooper Nuclear Station, Docket No. 50-298, DPR-46

Reference:

1. Letter from Michele G. Evans, U.S. Nuclear Regulatory Commission, to List of Addressees, including Oscar A. Limpias, Nebraska Public Power District, dated December 20, 2013, "Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System""

2. Letter from Brian J. O'Grady, Nebraska Public Power District, to U.S. Nuclear Regulatory Commission, dated October 24, 2012, "90-Day Response to NRC Bulletin 2012-01, Design Vulnerability in Electric Power System" (NLS2012081)

3. NRC Bulletin 2012-01, "Design Vulnerability in Electric Power System,"

dated July 27, 2012 (Accession No. ML12074A115)

Dear Sir or Madam:

The purpose of this letter is for Nebraska Public Power District (NPPD) to submit its response (Attachment 1) to the Nuclear Regulatory Commission (NRC) Request for Additional Information (Reference 1) for the Cooper Nuclear Station (CNS). This submittal is in addition to the NPPD submittal provided (Reference 2) in response to NRC Bulletin 2012-01 (Reference 3).

This letter contains a regulatory commitment. The commitment is described in Attachment 2 to this letter.

If you have any questions concerning this matter, please contact David W. Van Der Kamp, Licensing Manager, at (402) 825-2904.

COOPER NUCLEAR STATION P.O. Box 98 / Brownville, NE 68321-0098 Telephone: (402) 825-3877 / Fax: (402) 825-5211 www.nppd.com

NLS2014014 Page 2 of 2 I declare under penalty of perjury that the forgoing is true and correct.

Executed on: 04 //----

(Date Sinc elyIy Asc ýA. Limpli2 Vice President- uclear and Chief Nuclear Officer

/dm Attachments: 1. NPPD Response to Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System"

2. List of Regulatory Commitments cc: Regional Administrator w/attachments USNRC - Region IV Cooper Project Manager w/attachments USNRC - NRR Project Directorate IV- 1 Senior Resident Inspector w/attachments USNRC - CNS NPG Distribution w/attachments CNS Records w/attachments

NLS2014014 Attachment I Page 1 of 2 Attachment 1 Nebraska Public Power District Response to Request for Additional Information to Bulletin 2012-01, "Design Vulnerability in Electric Power Systems" The Nuclear Regulatory Commission (NRC) Request for Additional Information for Bulletin 2012-01 is shown in italics. The Nebraska Public Power District (NPPD) responses to the individual questions for Cooper Nuclear Station are shown in block font.

NRC letter (ADAMS ML13351A314) dated December 20, 2013 requests thefollowing:

"In orderfor the NRC staff to complete its review of responses to the bulletin, the following additionalinformation is requested:

1. Provide a summary ofall interim corrective actions that have been taken since the January30, 2012, event at Byron Station, Unit 2, to ensure thatplant operatorscan promptly diagnose and respond to open phase conditions on the offsite power circuitsfor Class-lE vital buses until permanent correctiveactions are completed.

NPPD Response Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at Cooper Nuclear Station. Based the plant's offsite power configuration, electrical design details, and on lessons learned, the following actions were taken to ensure plant operators can promptly diagnose and respond to open phase conditions (OPC):

• Interim Corrective Actions o Daily walk-downs are on-going of the switchyards to identify any potential conditions that could cause an OPC.

o Transformer yard rounds are performed daily and include general and detailed inspections of the transformers and inspection of external wiring and connections to identify any potential conditions that could cause an OPC.

o Operations procedures were revised to include recording all three phase voltages for each offsite power source at least once per shift.

NLS2014014 Attachment I Page 2 of 2

2. Provide a status and schedulefor completion ofplant design changes and modifications to resolve issues with an open phase of electricpower.

NPPD Response

• Status o Cooper Nuclear Station is investigating options being researched by several vendors (PSC2000, EPRI, Schweitzer, etc.) to detect OPC faults. There is currently no generic, off-the-shelf technology that has been proven to detect all the required open phase fault conditions for all plant and transformer designs.

o Cooper Nuclear Station is fully engaged in the development of the Nuclear Energy Institute (NEI) OPC Guidance Document, as well as development of enhancements to software tools being used to

/ analyze OPC faults.

o With the goal of ensuring accurate detection without compromising nuclear safety or increasing plant risk, this new OPC technology is being thoroughly evaluated, will be tested, and will be fully analyzed before installation.

o Vulnerability studies of the OPC faults have been started for Cooper Nuclear Station.

Schedule o Cooper Nuclear Station has committed to the generic schedule provided in the Industry OPC Initiative.

o It is our intention to meet the milestones of this schedule; however, deviations may be required to accommodate outage schedules, software and hardware availability, manufacturer's delivery capabilities, licensing delays, etc.

o Any deviation from the Industry OPC Initiative schedule will be documented through the deviation/exemption process addressed in the NEI OPC Guidance Document.

NLS2014014 Page 1 of I LIST OF REGULATORY COMMITMENTS The following table identifies those actions committed to by Nebraska Public Power District in this document. Any other actions discussed in this submittal are provided for information purposes and are not considered to be regulatory commitments.

TYPE (Check one) SCHEDULED COMMITMENT/COMMITMENT NO. ONE-TIME CONTINUING COMPLETION ACTION COMPLIANCE DATE Cooper Nuclear Station will follow the In accordance generic schedule provided in the Industry with the schedule Open Phase Conditions (OPC) Initiative. provided in the Any deviation from the Industry OPC Industry OPC Initiative schedule will be documented Initiative.

through the deviation/exemption process addressed in the NEI OPC Guidance Document. / NLS2014014-01

+ 4 4 EN-LI-106 Rev. 9C0, Attachment 9.3