L-2014-021, Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System
| ML14055A328 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 01/29/2014 |
| From: | Kiley M Florida Power & Light Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BL-12-001, L-2014-021 | |
| Download: ML14055A328 (6) | |
Text
0 FPL. January 29, 2014 L-2014-021 10 CFR 50.54(f)
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555-00001 Re: Turkey Point Units 3 and 4 Docket No. 50-250 and 50-251 Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System
References:
(1) NRC Bulletin 2012-01, Design Vulnerability in Electric Power System, July 27, 2012 (ML12074A115)
(2) FPL Letter to NRC, L-2012-374, Turkey Point Units 3 and 4 90-Day Response to NRC Bulletin 2012-01, Design Vulnerability in Electric Power System, October 16, 2012 (ML12312A275)
(3) NRC Letter to FPL, Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System," dated December 20, 2013 (ML 1335A314)
On July 27, 2012, the Nuclear Regulatory Commission ("NRC") issued Bulletin 2012-01, "Design Vulnerability in Electric Power System" (Reference 1). This bulletin described operating experience involving the loss of one of the three phases of the offsite power circuit (single-phase open circuit condition) at Byron Station, Unit 2, and, accordingly, requested Florida Power & Light Company ("FPL") to provide certain information about the electric power system design of the Turkey Point Nuclear Plant ("Turkey Point").
Turkey Point responded to this request by letter dated October 16, 2012 (Reference 2).
On December 20, 2013, the NRC requested additional information regarding Bulletin 2012-01 (Reference 3). The enclosure to this letter provides FPL's response to the Reference (3) request for Turkey Point.
This letter contains one new regulatory commitment in regards to committing to meeting the timeline in the NEI Open Phase Condition Initiative (October 2013). There are no revisions to existing regulatory commitments.
Florida Power & Light Company 9760 S.W. 344th Street Homestead, FL 33035
L-2014-021 Page 2 If you have any questions concerning this response, please contact Robert J. Tomonto, Licensing Manager, at 305-246-7327.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on January Z9? 2014.
Very truly yours, Michael Kiley Vice President Turkey Point Nuclear Plant rjt Enclosure cc: Administrator, Region II, USNRC Project Manager, Turkey Point Nuclear Plant, USNRC Resident Inspector, Turkey Point Nuclear Plant, USNRC
L-2014-021 Page 1 of 4 Enclosure Enclosure Turkey Point Units 3 and 4 Response to NRC Bulletin 2012-01 Design Vulnerability in Electric Power System
L-2014-021 Page 2 of 4 Enclosure Response to NRC 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" (Agencywide Documents Access and Management System Accession No. ML12074A115), to all holders of operating licenses and combined licenses for nuclear power reactors. NRC Bulletin 2012-01 requested information about each facility's electric power system designs, in light of recent operating experience involving the loss of one of the three phases of the offsite power circuit (single-phase open circuit condition) at Byron Station, Unit 2.
On December 20, 2013, NRC letter (ADAMS ML13351A314) requested additional information regarding Turkey Point Units 3 and 4 response to NRC Bulletin 2012-01, "Design Vulnerabilities in Electric Power System."
In order for the NRC staff to complete its review of responses to the bulletin, the following additional information is requested:
RAI I
- 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 offsite power circuits for Class-I E vital buses until permanent corrective actions are completed.
Response
Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at the Turkey Point Nuclear Units 3 and 4. Based on the plant's offsite power configuration, electrical design details, and lessons learned from the Byron event, the following actions were taken to ensure plant operators can promptly diagnose and respond to open phase conditions (OPC):
- Interim Corrective Actions o Once every shift, all three phase connections to the startup transformers are verified intact by plant operators (Inspected at Startup Transformers).
L-2014-021 Page 3 of 4 Enclosure o Once every shift, all three phase connections at the switchyard tower that go to the startup transformers are verified intact by plant operators (Inspected in Switchyard).
o Operators have reviewed the Byron loss of phase event during training re-qualification.
o Operators have been briefed on recognition of abnormal behavior of equipment associated with a switchyard OPC.
o Bi-annual thermography inspections of the switchyard equipment are performed.
RAI 2
- 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
Status o Turkey Point Nuclear Plant in cooperation with other holders of 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 technology that has been proven to detect all the required open phase fault conditions for Turkey Point Plant operating conditions.
o NextEra Energy Nuclear Fleet (Florida Power & Light Company is a wholly owned subsidiary of NextEra Energy, Inc) is 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.
L-2014-021 Page 4 of 4 Enclosure o Rebuilding of the switchyard transmission conductors to reduce the number of connections has been completed on Unit 4 (Unit 3 to be completed in April 2014).
o FPL Transmission has performed initial testing of a potential design solution for the open phase issue.
'Schedule o Turkey Point Nuclear Units 3 and 4 have committed to the generic schedule provided in the NEI Industry OPC Initiative, dated October 9,2013.
o Turkey Point intends 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 deviations from the NEI Industry OPC Initiative schedule will be documented through the deviation/exemption process being developed in the NEI OPC Guidance Document.
Text
0 FPL. January 29, 2014 L-2014-021 10 CFR 50.54(f)
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555-00001 Re: Turkey Point Units 3 and 4 Docket No. 50-250 and 50-251 Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System
References:
(1) NRC Bulletin 2012-01, Design Vulnerability in Electric Power System, July 27, 2012 (ML12074A115)
(2) FPL Letter to NRC, L-2012-374, Turkey Point Units 3 and 4 90-Day Response to NRC Bulletin 2012-01, Design Vulnerability in Electric Power System, October 16, 2012 (ML12312A275)
(3) NRC Letter to FPL, Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System," dated December 20, 2013 (ML 1335A314)
On July 27, 2012, the Nuclear Regulatory Commission ("NRC") issued Bulletin 2012-01, "Design Vulnerability in Electric Power System" (Reference 1). This bulletin described operating experience involving the loss of one of the three phases of the offsite power circuit (single-phase open circuit condition) at Byron Station, Unit 2, and, accordingly, requested Florida Power & Light Company ("FPL") to provide certain information about the electric power system design of the Turkey Point Nuclear Plant ("Turkey Point").
Turkey Point responded to this request by letter dated October 16, 2012 (Reference 2).
On December 20, 2013, the NRC requested additional information regarding Bulletin 2012-01 (Reference 3). The enclosure to this letter provides FPL's response to the Reference (3) request for Turkey Point.
This letter contains one new regulatory commitment in regards to committing to meeting the timeline in the NEI Open Phase Condition Initiative (October 2013). There are no revisions to existing regulatory commitments.
Florida Power & Light Company 9760 S.W. 344th Street Homestead, FL 33035
L-2014-021 Page 2 If you have any questions concerning this response, please contact Robert J. Tomonto, Licensing Manager, at 305-246-7327.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on January Z9? 2014.
Very truly yours, Michael Kiley Vice President Turkey Point Nuclear Plant rjt Enclosure cc: Administrator, Region II, USNRC Project Manager, Turkey Point Nuclear Plant, USNRC Resident Inspector, Turkey Point Nuclear Plant, USNRC
L-2014-021 Page 1 of 4 Enclosure Enclosure Turkey Point Units 3 and 4 Response to NRC Bulletin 2012-01 Design Vulnerability in Electric Power System
L-2014-021 Page 2 of 4 Enclosure Response to NRC 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" (Agencywide Documents Access and Management System Accession No. ML12074A115), to all holders of operating licenses and combined licenses for nuclear power reactors. NRC Bulletin 2012-01 requested information about each facility's electric power system designs, in light of recent operating experience involving the loss of one of the three phases of the offsite power circuit (single-phase open circuit condition) at Byron Station, Unit 2.
On December 20, 2013, NRC letter (ADAMS ML13351A314) requested additional information regarding Turkey Point Units 3 and 4 response to NRC Bulletin 2012-01, "Design Vulnerabilities in Electric Power System."
In order for the NRC staff to complete its review of responses to the bulletin, the following additional information is requested:
RAI I
- 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 offsite power circuits for Class-I E vital buses until permanent corrective actions are completed.
Response
Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at the Turkey Point Nuclear Units 3 and 4. Based on the plant's offsite power configuration, electrical design details, and lessons learned from the Byron event, the following actions were taken to ensure plant operators can promptly diagnose and respond to open phase conditions (OPC):
- Interim Corrective Actions o Once every shift, all three phase connections to the startup transformers are verified intact by plant operators (Inspected at Startup Transformers).
L-2014-021 Page 3 of 4 Enclosure o Once every shift, all three phase connections at the switchyard tower that go to the startup transformers are verified intact by plant operators (Inspected in Switchyard).
o Operators have reviewed the Byron loss of phase event during training re-qualification.
o Operators have been briefed on recognition of abnormal behavior of equipment associated with a switchyard OPC.
o Bi-annual thermography inspections of the switchyard equipment are performed.
RAI 2
- 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
Status o Turkey Point Nuclear Plant in cooperation with other holders of 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 technology that has been proven to detect all the required open phase fault conditions for Turkey Point Plant operating conditions.
o NextEra Energy Nuclear Fleet (Florida Power & Light Company is a wholly owned subsidiary of NextEra Energy, Inc) is 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.
L-2014-021 Page 4 of 4 Enclosure o Rebuilding of the switchyard transmission conductors to reduce the number of connections has been completed on Unit 4 (Unit 3 to be completed in April 2014).
o FPL Transmission has performed initial testing of a potential design solution for the open phase issue.
'Schedule o Turkey Point Nuclear Units 3 and 4 have committed to the generic schedule provided in the NEI Industry OPC Initiative, dated October 9,2013.
o Turkey Point intends 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 deviations from the NEI Industry OPC Initiative schedule will be documented through the deviation/exemption process being developed in the NEI OPC Guidance Document.