ML14043A106

Comanche Peak, Units 1 and 2, Response to Request for Additional Information for Bulletin 2012-01, Design Vulnerability in Electric Power System.

ML14043A106
Person / Time
Site:	Comanche Peak
Issue date:	01/30/2014
From:	Flores R, McCool T P Luminant Generation Co, Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL-12-001, CP-201301502, TXX-13189
Download: ML14043A106 (5)

Text

Rafael Flores Senior Vice President& Chief Nuclear Officer rafael.flores@luminant.com Luminant Power P 0 Box 1002 6322 North FM 56 Glen Rose, TX 76043 Luminant T 254 897 5590 C 817 559 0403 F 254 897 6652 CP-201301502 Log # TXX-13189 REF: REF: REF: REF: 10 CFR 50.54(f)10 CFR 50.55a(h)(2) 10 CFR 50.55a(h)(3)

BULLETIN 2012-01 January 30, 2014 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001

SUBJECT:

COMANCHE PEAK NUCLEAR POWER PLANT (CPNPP)UNITS 1 AND 2, DOCKET NUMBERS 50-445 AND 50-446 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR BULLETIN 2012-01, "DESIGN VULNERABILITY IN ELECTRIC POWER SYSTEM."

REFERENCES:

1. Nuclear Regulatory Commission (NRC)Bulletin 2012-01, "Design Vulnerability in Electric Power System" dated July 27, 2012.2. Luminant Power letter, Logged TXX-12122, from Rafael Flores to the NRC titled "90-Day Response to NRC Bulletin 2012-01, "Design Vulnerability in Electric Power System" dated October 25, 2012.3. NRC Request for Additional Information Regarding Response to Bulletin 2012-01, "Design Vulnerability in Electric Power System" dated December 20, 2013.

Dear Sir or Madam:

Reference 1 was the U.S. Nuclear Regulatory Commission (NRC)Bulletin 2012-01, "Design Vulnerability in Electric Power System." Reference 2 was Luminant Power's response to the NRC Bulletin.

Reference 3 is a NRC request for additional information (RAI) regarding Bulletin 2012-01 from licensees by February 3, 2014 to verify that they have completed interim corrective actions and compensatory measures and to determine the status of each licensee's long-term corrective actions. This letter provides the RAI response.If you have any questions regarding this report, please contact Tamera J. Ervin-Walker at 254-897-6902 or tamera.ervin@luminant.com.

This letter contains no new regulatory commitments.

I state under penalty of perjury that the foregoing is true and correct.Executed on January 30, 2014.A member of the STARS Alliance Callaway

• Comanche Peak -Diablo Canyon .Palo Verde

• Wolf Creek TXX-13189 Page 2 of 2 1/30/2014 Sincerely, Luminant Generation Company LLC Rafael Flores By: Thomas P. Vice President, Station Support TJEW Attachment 1: Response to Request for Additional Information for Bulletin 2012-01, "Design Vulnerability in Electric Power System." c -Michele G. Evans, Director, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation Wayne Walker, Region W Balwant K. Singal, NRR Resident Inspectors, Comanche Peak ATTACHMENT 1 to TXX-13189 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR BULLETIN 2012-01,"DESIGN VULNERABILITY IN ELECTRIC POWER SYSTEM."

Attachment 1 to TXX-13189 Page 2 of 3 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 offsite power circuits for Class-lE 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 -Summary of All Interim Corrective Actions Lessons learned from the events at Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at Comanche Peak Nuclear Power Plant. Based on 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 Periodic walk-downs are on-going of the switchyard to identify OPC vulnerabilities.

Specifically, the Transmission Operator performs switchyard walkdowns twice per week and Plant Equipment Operators perform switchyard inspections each shift and would detect such abnormal conditions as a fallen line to a startup transformer (ST).o Operating instructions and training curriculum were reviewed to ensure operators can diagnose and respond to an OPC.o Bus transfer procedures were verified to ensure three phase voltages are checked prior to bus transfers and after transfers complete.o Transformer yard rounds are performed each shift and include general and detailed inspections of the transformers to ensure parameters are within expected limits., Bi-annual infrared inspections of yard equipment are being completed as part of routine inspections.

o Operations procedures were revised to include recognition of equipment problems caused by OPC.Response 2 -Status and Schedule for Completion of Plant Design Changes Status o All holders of operating licenses and combined licenses for nuclear power reactors are investigating options being researched by several vendors (PSC2000, Electric Power Research Institute (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." All holders of operating licenses and combined licenses for nuclear power reactors are 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." 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." Vulnerability studies of the OPC faults have been completed for CPNPP. The results of the study showed that the existing undervoltage relaying will not detect all of the scenarios that were simulated.

Attachment 1 to TXX-13189 Page 3 of 3* Schedule o CPNPP 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.