ULNRC-06075, Response to Request for Additional Information Regarding Response to Bulletin 2012-01, Design Vulnerability in Electric Power System.

Response to Request for Additional Information Regarding Response to Bulletin 2012-01, Design Vulnerability in Electric Power System.

ML14030A423
Person / Time
Site:	Callaway
Issue date:	01/30/2014
From:	Reasoner C O Ameren Missouri, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL-12-001, ULNRC-06075
Download: ML14030A423 (6)

Text

WAmeren MISSOURI Cleve Reasoner Vice President Engineering Ameren Missouri Callaway Energy Center T 573.676.8241 F 573.676.4056

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January 30, 2014 ULNRC-06075 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Ladies and Gentlemen:

10 CFR 50.54(+/-) DOCKET NUMBER 50-483 CALLA WAY PLANT UNIT 1 UNION ELECTRIC CO. FACILITY OPERATING LICENSE NPF -30 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RESPONSE TO BULLETIN 2012-01, "DESIGN VULNERABILITY IN ELECTRIC POWER SYSTEM" On July 27, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued Bulletin 2012-01, "Design Vulnerability in Electric Power System," to all holders of operating licenses and combined licenses for nuclear power reactors.

Bulletin 2012-01 requested information about each facility's electric power system design. A response to this request was provided for Callaway Plant in an enclosure to Union Electric ( dba Ameren Missouri) letter ULNRC-05926, dated October 25, 2012. On December 20, 2013, the NRC issued a Request for Additional Information (RAI) to selected power reactor licensees and holders of construction permits regarding their responses to Bulletin 2012-01. The NRC RAI calls for a response by February 3, 2014. The information requested in response to the RAI for Callaway Plant is hereby provided in the enclosure to this letter. This letter does not contain new commitments.

Please contact Scott Maglio, Manager, Regulatory Affairs, at 573-676-8719 for any questions you may have regarding this issue. I declare under penalty of perjury that the foregoing is true and correct. Executed on: -----------------

Junction CC & Hwy 0 PO Box 620, MC CA-460 Cleveland

0. Reasoner Vice President, Engineering Fulton, MD 65251 AmerenMissouri.com STARS* Alliance ULNRC-06075 January 30, 2014 Page2 DRB/nls

Enclosure:

NRC Bulletin 2012-01 RAI Response ULNRC-06075 January 30, 2014 Page 3 cc: Mr. Marc L. Dapas Regional Administrator U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Fred Lyon Project Manager, Callaway Plant Office ofNuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8B 1 Washington, DC 20555-2738 ULNRC-0607 5 January 30, 2014 Page4 Index and send hardcopy to QA File A160.0761 Hardcopy:

Certrec Corporation 4150 International Plaza Suite 820 Fort Worth, TX 76109 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Responses and Reports ULNRC Distribution:

F. M. Diya C. 0. Reasoner III B. L. Cox L. H. Graessle S. G. Kovaleski S. A. Maglio T. B. Elwood M.D. Haag NSRB Secretary STARS Regulatory Affairs Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)

Enclosure to ULNRC-06075 Open Phase Condition NRC Bulletin 2012-01 RAI Response NRC letter (ADAMS ML13351A314) dated December 20, 2013 requests the following: "In order for the NRC staff to complete its review of responses to the bulletin, the following additional information is requested:

1. Provide a summary of all interim corrective actions that have been taken since the January 30, 2012, event at Byron Station, Unit 2, to ensure that plant operators can promptly diagnose and respond to open phase conditions on the off-site power circuits for Class-1 E vital buses until permanent corrective actions are completed.

2. Provide a status and schedule for completion of plant design changes and modifications to resolve issues with an open phase of electric power." Response 1 -Summarv of All Interim Corrective Actions Lessons learned from the January 30, 2012 event at Byron station were reviewed and various interim corrective actions were evaluated for safety and efficiency at callaway Plant. Based on the plant's off-site power configuration, electrical design details, and lessons learned, the following actions were taken to ensure plant operators can promptly diagnose and respond to an open phase condition (OPC):

• Interim Corrective Actions o The switchyard, off-site source power lines, and off-site source equipment were inspected for material condition and design vulnerabilities that could create OPC vulnerabilities, particular attention was given to support insulators without bus expansion joints. o Interim guidance has been given to the operating crews to make the crews aware of the open phase issue, to aid in identification of OPC events, and to provide appropriate operating actions in the event of an OPC. o Preliminary OPC analysis identified that with the shell form, wye-to-wye and core form, delta-to-wye transformers used at callaway, some detection capability exists to alarm and isolate with callaway's existing two-out-of-four coincidence, degraded voltage protection.

o Transformer and switchyard rounds are performed daily and include general and detailed inspections of the transformers and switchyard condition.

o Biannual infrared inspections of yard equipment are being completed as part of routine inspections and after disconnect switch operation to mitigate precursors leading to open phase conditions.

o Operations' alarm procedures were revised to include recognition of equipment problems caused by OPC and to provide appropriate isolation from the affected site source. Response 2 -Status and Schedule for Completion of Plant Design Changes

• Status 10jan14 o All holders of operating licenses and combined licenses for nuclear power reactors are investigating options being researched by several vendors (PSC2000, EPRI, Schweitzer, etc.) to detect OPC faults. There is currently no generic, off-the-shelf Page 1 Enclosure to ULNRC-06075 Open Phase Condition NRC Bulletin 2012-01 RAI Response technology that has been proven to detect all the required open phase fault conditions for all plant and transformer designs. o All holders of operating licenses and combined licenses for nuclear power reactors are fully engaged in the development of the 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 Electrical analysis studies of the OPC faults have been started for callaway Plant.

• Schedule 10jan14 o callaway Plant has committed to the generic schedule provided in the Industry OPC Initiative developed by NEI. 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.

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Text

WAmeren MISSOURI Cleve Reasoner Vice President Engineering Ameren Missouri Callaway Energy Center T 573.676.8241 F 573.676.4056

.................................................................................................................................................................................

.::::::

January 30, 2014 ULNRC-06075 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Ladies and Gentlemen:

10 CFR 50.54(+/-) DOCKET NUMBER 50-483 CALLA WAY PLANT UNIT 1 UNION ELECTRIC CO. FACILITY OPERATING LICENSE NPF -30 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RESPONSE TO BULLETIN 2012-01, "DESIGN VULNERABILITY IN ELECTRIC POWER SYSTEM" On July 27, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued Bulletin 2012-01, "Design Vulnerability in Electric Power System," to all holders of operating licenses and combined licenses for nuclear power reactors.

Bulletin 2012-01 requested information about each facility's electric power system design. A response to this request was provided for Callaway Plant in an enclosure to Union Electric ( dba Ameren Missouri) letter ULNRC-05926, dated October 25, 2012. On December 20, 2013, the NRC issued a Request for Additional Information (RAI) to selected power reactor licensees and holders of construction permits regarding their responses to Bulletin 2012-01. The NRC RAI calls for a response by February 3, 2014. The information requested in response to the RAI for Callaway Plant is hereby provided in the enclosure to this letter. This letter does not contain new commitments.

Please contact Scott Maglio, Manager, Regulatory Affairs, at 573-676-8719 for any questions you may have regarding this issue. I declare under penalty of perjury that the foregoing is true and correct. Executed on: -----------------

Junction CC & Hwy 0 PO Box 620, MC CA-460 Cleveland

0. Reasoner Vice President, Engineering Fulton, MD 65251 AmerenMissouri.com STARS* Alliance ULNRC-06075 January 30, 2014 Page2 DRB/nls

Enclosure:

NRC Bulletin 2012-01 RAI Response ULNRC-06075 January 30, 2014 Page 3 cc: Mr. Marc L. Dapas Regional Administrator U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Fred Lyon Project Manager, Callaway Plant Office ofNuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8B 1 Washington, DC 20555-2738 ULNRC-0607 5 January 30, 2014 Page4 Index and send hardcopy to QA File A160.0761 Hardcopy:

Certrec Corporation 4150 International Plaza Suite 820 Fort Worth, TX 76109 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Responses and Reports ULNRC Distribution:

F. M. Diya C. 0. Reasoner III B. L. Cox L. H. Graessle S. G. Kovaleski S. A. Maglio T. B. Elwood M.D. Haag NSRB Secretary STARS Regulatory Affairs Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)

Enclosure to ULNRC-06075 Open Phase Condition NRC Bulletin 2012-01 RAI Response NRC letter (ADAMS ML13351A314) dated December 20, 2013 requests the following: "In order for the NRC staff to complete its review of responses to the bulletin, the following additional information is requested:

1. Provide a summary of all interim corrective actions that have been taken since the January 30, 2012, event at Byron Station, Unit 2, to ensure that plant operators can promptly diagnose and respond to open phase conditions on the off-site power circuits for Class-1 E vital buses until permanent corrective actions are completed.

2. Provide a status and schedule for completion of plant design changes and modifications to resolve issues with an open phase of electric power." Response 1 -Summarv of All Interim Corrective Actions Lessons learned from the January 30, 2012 event at Byron station were reviewed and various interim corrective actions were evaluated for safety and efficiency at callaway Plant. Based on the plant's off-site power configuration, electrical design details, and lessons learned, the following actions were taken to ensure plant operators can promptly diagnose and respond to an open phase condition (OPC):

• Interim Corrective Actions o The switchyard, off-site source power lines, and off-site source equipment were inspected for material condition and design vulnerabilities that could create OPC vulnerabilities, particular attention was given to support insulators without bus expansion joints. o Interim guidance has been given to the operating crews to make the crews aware of the open phase issue, to aid in identification of OPC events, and to provide appropriate operating actions in the event of an OPC. o Preliminary OPC analysis identified that with the shell form, wye-to-wye and core form, delta-to-wye transformers used at callaway, some detection capability exists to alarm and isolate with callaway's existing two-out-of-four coincidence, degraded voltage protection.

o Transformer and switchyard rounds are performed daily and include general and detailed inspections of the transformers and switchyard condition.

o Biannual infrared inspections of yard equipment are being completed as part of routine inspections and after disconnect switch operation to mitigate precursors leading to open phase conditions.

o Operations' alarm procedures were revised to include recognition of equipment problems caused by OPC and to provide appropriate isolation from the affected site source. Response 2 -Status and Schedule for Completion of Plant Design Changes

• Status 10jan14 o All holders of operating licenses and combined licenses for nuclear power reactors are investigating options being researched by several vendors (PSC2000, EPRI, Schweitzer, etc.) to detect OPC faults. There is currently no generic, off-the-shelf Page 1 Enclosure to ULNRC-06075 Open Phase Condition NRC Bulletin 2012-01 RAI Response technology that has been proven to detect all the required open phase fault conditions for all plant and transformer designs. o All holders of operating licenses and combined licenses for nuclear power reactors are fully engaged in the development of the 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 Electrical analysis studies of the OPC faults have been started for callaway Plant.

• Schedule 10jan14 o callaway Plant has committed to the generic schedule provided in the Industry OPC Initiative developed by NEI. 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.

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