NG-14-0032, NextEra Energy Duane Arnold, LLC Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System
| ML14034A107 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 01/30/2014 |
| From: | Richard Anderson NextEra Energy Duane Arnold |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BL-12-001, NG-14-0032 | |
| Download: ML14034A107 (5) | |
Text
NExTera EN ERGY2MO.
ý;ýARNOLD January 30, 2014 NG-14-0032 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Duane Arnold Energy Center Docket No. 50-331 Renewed Op. License No. DPR-49 NextEra Energy Duane Arnold, LLC Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Desiqn Vulnerability in Electric Power System
References:
- 1) NRC Bulletin 2012-01, "Design Vulnerability in Electric Power System," dated July 27, 2012 (ML12074A115)
- 2) Letter, R. Anderson (NextEra Energy Duane Arnold, LLC) to U. S. NRC, NextEra Energy Duane Arnold, LLC Response to NRC Bulletin 2012-01 Design Vulnerability in Electric Power System, NG-12-0447, dated October 25, 2012 (ML12307A055)
- 3) NRC letter, Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System," dated December 20, 2013 (ML13351A314)
On July 27, 2012, the Nuclear Regulatory Commission (NRC) issued Bulletin (BL) 2012-01, "Design Vulnerability in Electric Power System." In response to an event at Byron Station, Unit 2 that involved the loss of one of the three phases of the offsite power circuit, BL 2012-01 requested licensees provide electric power system design information. In Reference 2, NextEra Energy Duane Arnold, LLC (hereafter NextEra Energy Duane Arnold) provided the requested information.
The NRC requested additional information regarding Bulletin 2012-01 via Reference 3. The enclosure to this letter provides the requested information.
NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324
Document Control Desk NG-14-0032 Page 2 of 2 This letter makes no changes to existing commitments and makes the following new commitment.
NextEra Energy Duane Arnold hereby commits to the generic schedule provided in NEI 13-12, Open Phase Condition Industry Guidance Document. It is our intention to meet the milestones of this schedule; however, any deviation from the generic schedule will be documented through the deviation/exemption process addressed in the NEI 13-12, Open Phase Condition Industry Guidance Document when it is available.
If you have any questions, please contact J. Michael Davis at (319) 851-7032.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on January 30, 2014 Richard L. Anders(n Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC Enclosure cc: Administrator, Region Ill, USNRC Project Manager, DAEC, USNRC Senior Resident Inspector, DAEC, USNRC
Enclosure to NG-14-0032 NextEra Energy Duane Arnold, LLC Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System 2 pages follow
NextEra Energy Duane Arnold, LLC Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System NRC Request 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 operatorscan promptly diagnose and respond to open phase conditions on the offsite power circuits for Class-I E vital buses until permanentcorrective actions are completed.
NextEra Energy Duane Arnold Response to Request 1:
Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at Duane Arnold Energy Center (DAEC). Based on DAEC's offsite power configuration, electrical design details, and 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 A Prompt Operability Determination (POD) was performed to verify that DAEC was in compliance with its licensing basis.
o Once per day, all three phase connections to the Startup Transformer are verified intact by plant operators (Inspected at Startup Transformer).
o Once per day, all three phase connections at the switchyard tower that go to the Startup Transformer are verified intact by plant operators (Inspected in Switchyard).
o Semiannual infrared inspections of the Startup Transformer and Switchyard equipment are being completed as part of routine inspections.
o Discussion of the Byron event was included in plant operator training to help plant operators understand the event and be aware of the condition at DAEC.
NRC Request 2:
Provide a status and schedule for completion of plant design changes and modifications to resolve issues with an open phase of electric power.
Page 1 of 2
NextEra Energy Duane Arnold Response to Request 2:
0 Status o As part of a larger industry effort, NextEra Energy Duane Arnold 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 As part of a larger industry effort, NextEra Energy Duane Arnold is fully engaged in the development of NEI 13-12, Open Phase Condition Industry 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, the OPC technology discussed above is being thoroughly evaluated, will be tested, and will be fully analyzed before installation.
o NextEra Energy Duane Arnold has determined design modifications are warranted to ensure an open phase condition would be automatically detected. NextEra Energy Duane Arnold has initiated a project and is in the process of finalizing project approval.
o NextEra Energy Duane Arnold has performed initial testing and development (T&D) of a potential design solution to determine viability of design solution for the open phase issue.
Schedule o NextEra Energy Duane Arnold hereby commits to the generic schedule provided in NEI 13-12, Open Phase Condition Industry Guidance Document. It is our intention to meet the milestones of this schedule; however, any deviation from the generic schedule will be documented through the deviation/exemption process addressed in the NEI 13-12, Open Phase Condition Industry Guidance Document when it is available.
Page 2 of 2
Text
NExTera EN ERGY2MO.
ý;ýARNOLD January 30, 2014 NG-14-0032 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Duane Arnold Energy Center Docket No. 50-331 Renewed Op. License No. DPR-49 NextEra Energy Duane Arnold, LLC Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Desiqn Vulnerability in Electric Power System
References:
- 1) NRC Bulletin 2012-01, "Design Vulnerability in Electric Power System," dated July 27, 2012 (ML12074A115)
- 2) Letter, R. Anderson (NextEra Energy Duane Arnold, LLC) to U. S. NRC, NextEra Energy Duane Arnold, LLC Response to NRC Bulletin 2012-01 Design Vulnerability in Electric Power System, NG-12-0447, dated October 25, 2012 (ML12307A055)
- 3) NRC letter, Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System," dated December 20, 2013 (ML13351A314)
On July 27, 2012, the Nuclear Regulatory Commission (NRC) issued Bulletin (BL) 2012-01, "Design Vulnerability in Electric Power System." In response to an event at Byron Station, Unit 2 that involved the loss of one of the three phases of the offsite power circuit, BL 2012-01 requested licensees provide electric power system design information. In Reference 2, NextEra Energy Duane Arnold, LLC (hereafter NextEra Energy Duane Arnold) provided the requested information.
The NRC requested additional information regarding Bulletin 2012-01 via Reference 3. The enclosure to this letter provides the requested information.
NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324
Document Control Desk NG-14-0032 Page 2 of 2 This letter makes no changes to existing commitments and makes the following new commitment.
NextEra Energy Duane Arnold hereby commits to the generic schedule provided in NEI 13-12, Open Phase Condition Industry Guidance Document. It is our intention to meet the milestones of this schedule; however, any deviation from the generic schedule will be documented through the deviation/exemption process addressed in the NEI 13-12, Open Phase Condition Industry Guidance Document when it is available.
If you have any questions, please contact J. Michael Davis at (319) 851-7032.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on January 30, 2014 Richard L. Anders(n Vice President, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC Enclosure cc: Administrator, Region Ill, USNRC Project Manager, DAEC, USNRC Senior Resident Inspector, DAEC, USNRC
Enclosure to NG-14-0032 NextEra Energy Duane Arnold, LLC Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System 2 pages follow
NextEra Energy Duane Arnold, LLC Response to Request for Additional Information Regarding NRC Bulletin 2012-01, Design Vulnerability in Electric Power System NRC Request 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 operatorscan promptly diagnose and respond to open phase conditions on the offsite power circuits for Class-I E vital buses until permanentcorrective actions are completed.
NextEra Energy Duane Arnold Response to Request 1:
Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at Duane Arnold Energy Center (DAEC). Based on DAEC's offsite power configuration, electrical design details, and 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 A Prompt Operability Determination (POD) was performed to verify that DAEC was in compliance with its licensing basis.
o Once per day, all three phase connections to the Startup Transformer are verified intact by plant operators (Inspected at Startup Transformer).
o Once per day, all three phase connections at the switchyard tower that go to the Startup Transformer are verified intact by plant operators (Inspected in Switchyard).
o Semiannual infrared inspections of the Startup Transformer and Switchyard equipment are being completed as part of routine inspections.
o Discussion of the Byron event was included in plant operator training to help plant operators understand the event and be aware of the condition at DAEC.
NRC Request 2:
Provide a status and schedule for completion of plant design changes and modifications to resolve issues with an open phase of electric power.
Page 1 of 2
NextEra Energy Duane Arnold Response to Request 2:
0 Status o As part of a larger industry effort, NextEra Energy Duane Arnold 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 As part of a larger industry effort, NextEra Energy Duane Arnold is fully engaged in the development of NEI 13-12, Open Phase Condition Industry 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, the OPC technology discussed above is being thoroughly evaluated, will be tested, and will be fully analyzed before installation.
o NextEra Energy Duane Arnold has determined design modifications are warranted to ensure an open phase condition would be automatically detected. NextEra Energy Duane Arnold has initiated a project and is in the process of finalizing project approval.
o NextEra Energy Duane Arnold has performed initial testing and development (T&D) of a potential design solution to determine viability of design solution for the open phase issue.
Schedule o NextEra Energy Duane Arnold hereby commits to the generic schedule provided in NEI 13-12, Open Phase Condition Industry Guidance Document. It is our intention to meet the milestones of this schedule; however, any deviation from the generic schedule will be documented through the deviation/exemption process addressed in the NEI 13-12, Open Phase Condition Industry Guidance Document when it is available.
Page 2 of 2