ML14043A111
| ML14043A111 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 02/03/2014 |
| From: | Costanzo C Constellation Energy Nuclear Group, EDF Group, Nine Mile Point |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BL-12-001 | |
| Download: ML14043A111 (8) | |
Text
Christopher R. Costanzo Office: 315-349-5205 Vice President - Nine Mile Point Fax: 315-349-1321 Email: Christopher.Costanzo@cenglIc.com CENG.
a joint venture of Energy-4 NINE MILE POINT NUCLEAR STATION February 3, 2014 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
Document Control Desk
SUBJECT:
Nine Mile Point Nuclear Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-63 and NPF-69 Docket Nos. 50-220 and 50-410 NRC Bulletin 2012-01: Design Vulnerability in Electric Power System - Response to NRC Request for Additional Information
REFERENCE:
(a)
NRC Bulletin 2012-01, Design Vulnerability in Electric Power System, dated July 27, 2012 (ML12074A115)
(b)
Letter from M. A. Philippon (NMPNS) to Document Control Desk (NRC),
NRC Bulletin 2012-01: Design Vulnerability in Electric Power System, dated October 25, 2012 (ML12306A087)
(c)
Letter from M. A. Philippon (NMPNS) to Document Control Desk (NRC),
NRC Bulletin 2012-01: Design Vulnerability in Electric Power System -
Supplemental Response, dated December 7, 2012 (ML12348A394)
(d)
Letter from M. G. Evans (NRC) to all holders of operating licenses and combined licenses, 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 U. S. Nuclear Regulatory Commission (NRC) issued Bulletin 2012-01, "Design Vulnerability in Electric Power System" (Reference a). Pursuant to 10 CFR 50.54(f), the NRC requested that all holders of operating licenses and combined licenses provide information regarding the facilities' electric power systems and verify compliance with General Design Criteria (GDC) 17, "Electric Power Systems." By letter dated October 25, 2012 (Reference b) and as supplemented by letter dated December 7, 2012 (Reference c), Nine Mile Point Nuclear Station, LLC (NMPNS) provided the response to NRC Bulletin 2012-01 for Nine Mile Point Unit 1 and Unit 2 (NMPI and NMP2).
Nine Mile Point Nuclear Station, LLC
>612 P.O. Box 63 Lycoming, NY 13093
Document Control Desk February 3, 2014 Page 2 Attachments (1) and (2) provide the NMPNS response to the NRC's request for additional information dated December 20, 2013 (Reference d).
This letter contains no new regulatory commitments. Should you have any questions regarding the information in this submittal, please contact Everett (Chip) Perkins, Director - Licensing, at (315) 349-5219.
I declare under penalty of perjury that the foregoing is true and correct. Executed on February 3, 2014 Sincerely, CRC/BTV Attachments:
- 1. Nine Mile Point Unit 1 Response to Bulletin 2012-01 Request for Additional Information
- 2. Nine Mile Point Unit 2 Response to Bulletin 2012-01 Request for Additional Information cc:
Regional Administrator, Region I, NRC Project Manager, NRC Resident Inspector, NRC
ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO BULLETIN 2012-01 REQUEST FOR ADDITIONAL INFORMATION Nine Mile Point Nuclear Station, LLC February 3, 2014
ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION By letter dated October 25, 2012 (Reference b), and as supplemented by letter dated December 7, 2012 (Reference c), Nine Mile Point Nuclear Station, LLC (NMPNS) provided the response to NRC Bulletin 2012-01 for Nine Mile Point Unit I and Unit 2 (NMP1 and NMP2).
By letter dated December 20, 2013 the NRC staff sent a request for additional information regarding the NMPNS response to NRC Bulletin 2012-01. This attachment provides the requested information for NMP1.
The NRC request is repeated (in italics), followed by the NMPNS response.
RAI #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."
Nine Mile Point Unit 1 (NMP1) Response Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at NMP1. Based on the plant's offsite power configuration, electrical design details, and lessons learned, the following interim actions have been taken to ensure that plant operators can promptly diagnose and respond to open phase conditions (OPC) on the offsite power circuits for Class-IE vital buses. The following interim actions will remain in place until permanent corrective actions are completed, as discussed in the response to RAI #2.
Control Room Shift Managers were briefed on the Byron event including operating indications that would be present for a similar event at NMP1.
Switchyard walkdowns are performed daily and include inspections that would detect a visible loss of phase on the reserve transformers. Operations personnel were shown pictures from the event at Byron station to assist them in recognizing potential OPC vulnerabilities during walkdowns of the switchyard.
Procedure NI-ST-SO, "Shift Checks," was revised to increase the frequency that operators take Line I and Line 4 amperage readings from twice a day to every four hours. The readings are taken upstream of the 115 kV bus.
The revision also added additional guidance to direct operators to enter Ni-OP-33A, "115 kV System" for a loss of line if an OPC exists for that line.
Procedure NI-PM-Si, "Operator's Rounds Guide," was revised to add a requirement to monitor the voltage of each phase of the 115 kV bus during control room monitoring rounds.
Procedure Ni-ARP-A4, "Control Room Panel A4," was revised to add an OPC on the offsite power circuit as a possible cause for control room alarm, "Power Board 102 Bus Voltage Low."
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ATTACHMENT 1 NINE MILE POINT UNIT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION Procedure N1-ARP-A5, "Control Room Panel A5," was revised to add an OPC on the offsite power circuit as a possible cause for control room alarm for, "Power Board 103 Bus Voltage Low."
RAI #2 "Provide a status and schedule for completion of plant design changes and modifications to resolve issues with an open phase of electric power."
Nine Mile Point Unit 1 (NMP1) Response Status An analysis to determine if NMP1 is vulnerable to an open phase condition going undetected on the offsite power circuits for Class-IE vital buses has been completed. The results indicate that existing relaying may not pick up on an open phase condition; therefore NMP1 is vulnerable to an open phase condition.
Constellation Energy Nuclear Group (CENG) and NMPNS will continue to participate in the industry user groups to develop a suitable protective relay scheme that will be able to detect and respond to 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. With the goal of ensuring accurate detection without compromising nuclear safety or increasing plant risk, new OPC technology is being thoroughly evaluated, and will be tested and fully analyzed before installation.
NMP1 will adopt a design similar to the industry developed solution which will be installed on the high voltage side of the Station Reserve Transformers which feed Class-lE vital buses. An engineering design package is currently being developed to install the digital relays for open phase detection. The relay will initially be used for indication purposes only; the trip function of the relay will be enabled at a later time as dictated by the Nuclear Energy Institute (NEI) OPC Initiative.
Schedule NMPNS has committed to following the generic schedule provided in the NEI OPC Initiative. NMPNS 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.
Any deviation from the NEI OPC Initiative schedule will be documented through the deviation/exemption process addressed in the NEI OPC Initiative document.
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ATTACHMENT 2 NINE MILE POINT UNIT 2 RESPONSE TO BULLETIN 2012-01 REQUEST FOR ADDITIONAL INFORMATION Nine Mile Point Nuclear Station, LLC February 3, 2014
ATTACHMENT 2 NINE MILE POINT UNIT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION By letter dated October 25, 2012 (Reference b) and as supplemented by letter dated December 7, 2012 (Reference c), Nine Mile Point Nuclear Station, LLC (NMPNS) provided the response to NRC Bulletin 2012-01 for Nine Mile Point Unit 1 and Unit 2 (NMP1 and NMP2).
By letter dated December 20, 2013 the NRC staff sent a request for additional information regarding the NMPNS response to NRC Bulletin 2012-01. This attachment provides the requested information for NMP2.
The NRC request is repeated (in italics), followed by the NMP2 response RAI #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."
Nine Mile Point Unit 2 (NMP2) Response Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at NMP2. Based on the plant's offsite power configuration, electrical design details, and lessons learned, the following interim actions have been taken to ensure that plant operators can promptly diagnose and respond to open phase conditions (OPC) on the offsite power circuits for Class-IE vital buses. The following interim actions will remain in place until permanent corrective actions are completed, as discussed in the response to RAI #2.
Control Room Shift Managers were briefed on the Byron event including operating indications that would be present for a similar event at NMP2.
Switchyard walkdowns are performed daily and include inspections that would detect a visible loss of phase on the reserve transformers. Operations personnel were shown pictures from the event at Byron station to assist them in recognizing potential OPC vulnerabilities during walkdowns of the switchyard.
Procedure N2-ARP-852100, "2CEC*PNL852 Series 100 Alarm Response Procedures," was revised to add a loss of a single phase of offsite power as a possible cause for control room alarm "4 kV Bus 101 Undervoltage." A note was also added that states "Loss of a single phase of 115 kV offsite power may result in a bus undervoltage alarm, but no automatic action. The affected phase 115 kV phase voltage and current reading zero would confirm the condition." The revised procedure adds direction to remove the associated line from service in accordance with procedure N2-OP-70, "Station Electrical Feed and 115 kV Switchyard" if an OPC is indicated.
Procedure N2-ARP-852200, "2CEC*PNL852 Series 200 Alarm Response Procedures" was revised to add loss of a single phase of offsite power as a possible cause for control room alarm "4 kV Bus 103 Undervoltage." A note was also added that states "Loss of a single phase of 115 kV offsite power may result in a bus undervoltage alarm, but no automatic action. The affected 1 of 2
V.
ATTACHMENT 2 NINE MILE POINT UNIT 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION phase 115 kV phase voltage and current reading zero would confirm the condition." The revised procedure adds direction to remove the associated line from service in accordance with procedure N2-OP-70, "Station Electrical Feed and 115 kV Switchyard" if an OPC is indicated.
RAI #2 "Provide a status and schedule for completion of plant design changes and modifications to resolve issues with an open phase of electric power.
Nine Mile Point Unit 2 (NMP2) Response Status An analysis to determine if NMP2 is vulnerable to an open phase condition going undetected on the offsite power circuits for Class-lE vital buses has been completed. The results indicate that existing relaying may not pick up on an open phase condition; therefore NMP2 is vulnerable to an open phase condition.
Constellation Energy Nuclear Group (CENG) and Nine Mile Point Nuclear Station will continue to participate in industry user groups to develop a suitable protective relay scheme that will be able to detect and respond to 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. With the goal of ensuring accurate detection without compromising nuclear safety or increasing plant risk, new OPC technology is being thoroughly evaluated, and will be tested and fully analyzed before installation.
NMP2 will adopt a design similar to the industry developed solution which will be installed on the high voltage side of the Station Reserve Transformers which feed Class-IE vital buses. An engineering design package is currently being developed to install the digital relays for open phase detection. The relay will initially be used for indication purposes only; the trip function of the relay will be enabled at a later time as dictated by the Nuclear Energy Institute (NEI) OPC Initiative.
Schedule NMPNS has committed to following the generic schedule provided in the NEI OPC Initiative. NMPNS 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.
Any deviation from the NEI OPC Initiative schedule will be documented through the deviation/exemption process addressed in the NEI OPC Initiative document.
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