ULNRC-06554, Follow-Up Action for Response to NRC Bulletin 2012-01: Extension of Implementation Period for Activating Open Phase Isolation System Installed at Callaway Plant

Follow-Up Action for Response to NRC Bulletin 2012-01: Extension of Implementation Period for Activating Open Phase Isolation System Installed at Callaway Plant

ML19344D210
Person / Time
Site:	Callaway
Issue date:	12/10/2019
From:	Bianco F Ameren Missouri, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL 2012-01, ULNRC-06554
Download: ML19344D210 (5)

Text

7AIIIeIefl Callaway Plant MISSOURI December 10, 2019 ULNRC-06554 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-000 1 10 CFR 50.54(f)

Ladies and Gentlemen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

RENEWED FACILITY OPERATING LICENSE NPF-30 FOLLOW-UP ACTION FOR RESPONSE TO NRC BULLETIN 2012-01:

EXTENSION OF IMPLEMENTATION PERIOD FOR ACTIVATING OPEN PHASE ISOLATION SYSTEM INSTALLED AT CALLAWAY PLANT

References:

(1) Ameren Missouri letter ULNRC-05926, 90-Day Response to NRC Bulletin 20 12-01 Design Vulnerability in Electric Power System, dated October 24, 2012 (2) NRC letter dated December 20, 201 3 Request for Additional Information Regarding Response to Bulletin 2012-01, Design Vulnerability in Electric Power System (3) Ameren Missouri letter ULNRC-06075, Response to Request for Additional Information Regarding Response to Bulletin 2012-01 Design vulnerability in Electric Power System, dated January 30, 2014 (4) NEI letter to Mr. Ho Nieh, Jr., Director, Office ofNuclear Reactor Regulation, U.S.

NRC, dated September 20, 2018 This letter is submitted in order to inform the NRC of a change in the implementation schedule for Ameren Missouris response to NRC Bulletin 2012-01 Design Vulnerability in Electric Power System. Following Ameren Missouris initial response to NRC Bulletin 2012-01 as submitted per Reference 1 a follow-up letter (Reference 3) was submitted in response to a Request for Additional Information (RAI) received from the NRC per Reference 2. The information provided in the follow-up letter included the status and schedule for completion of a plant modification to resolve the issue

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ULNRC-06554 December 10, 2019 Page 2 of 5 concerning the potential effects of an open phase in the offsite power sources or source connections to the plant.

In describing the schedule that would be followed for development and implementation of a modification at the Callaway Plant, the letter acknowledged Ameren Missouris alignment with the generic schedule provided in the Industry OPC Initiative developed by NET in 2013 Per that schedule, plant modifications for installation of an Open Phase Isolation System (OPTS) at each applicable plant were to be implemented by December 3 1 201 2 As Ameren Missouri indicated in the Reference 3 letter, It is our intention to meet the milestones of this schedule; however, deviations may be required to accommodate outage schedules, software and hardware availability, manufacturers delivery capabilities, licensing delays, etc. Any deviation from the Industry OPC Initiative schedule will be documented through the deviationlexemption process addressed in the NET OPC Guidance Document.

The NEI OPC initiative for the industry underwent some changes from the initially developed version, and Revision 1 was formally approved by the industry in 201 5 As plants subsequently began to complete their OPTS modifications, the approach taken was to initially maintain the installed systems in a monitoring/alarm mode only in order to monitor performance prior to activating the trip capability of the systems. In its letter dated September 20, 201 8 (Reference 4), NET informed the NRC that Revision 2 of the OPC Tnitiative was being issued. It was noted in the letter that revision of the originally described schedule was needed in order to provide adequate time for implementation of the necessary modifications to the plants and to accommodate an adequate monitoring time afterwards.

The following was noted in the letter:

Many plants have completed installation of their Open Phase Isolation System (OPTS) with other plants scheduled to complete during 201 8 Monitoring data to date indicates that installed OPTSs would have experienced spurious actuations ifthe automatic trip functions had been activated. Some spurious actuation causes are unknown and resolutions are still being pursued. Additionally, due to the limited monitoring period remaining before December 3 1, 201 8, there is some uncertainty that all existing and potentially new plant/grid configurations can be reliable handled by the various OPTS designs without including spurious actuations. As a result, the industry has recognized the need for an extended monitoring period necessitating a second revision the industry initiative.

As specified in the letter, a 24-month monitoring period was deemed to be sufficient before fully implementing the plant OPTS modifications (i.e., with their automatic trip capability enabled).

At Callaway, installation ofthe OPTS was completed in late 2017. The system was installed with the capability to effect automatic isolation of an offsite source experiencing an open-phase condition, but like most plants, the automatic trip capability was not enabled in order to allow for a monitoring period with the OPTS installed in an alarm-only mode. following a favorable monitoring period, the intent was for the installed OPTS to be fully implemented with its as-designed automatic trip capability enabled, in accordance with the NET OPC Initiative. This two-step approach to implementing the modification required the licensing activities for the OPTS to also be completed in two steps, particularly in regard to 1 0 CFR 50.59 review of the modification. The licensing activity for

ULNRC-06554 December 10, 2019 Page 3 of 5 supporting the enabling and full implementation of the OPTS at Callaway, including performance of a 10 CFR 50.59 Evaluation, wasjust recently completed.

The 10 CFR 50.59 Evaluation recently completed, reviewed and approved by Callaway personnel was supported by the fact that the OPTS for Callaway employs both a non-safety relay package in the switchyard with alarm capability and a package of safety-related (Class TE) relays installed in the feeder breaker trip circuits for the plant 4. 16-ky safety buses, providing alarm and automatic trip capability for effecting offsite source isolation. The latter utilizes 2-out-of-2 coincidence logic to minimize the potential for inadvertent trips. It may be noted that during the 24-month monitoring period now completed for these relays, no spurious alarms from the Class 1E relays were experienced.

Having just completed the 24-month monitoring period and the 1 0 CFR 50.59 Evaluation for enabling the automatic trip capability of the OPTS at Callaway, release of the modification for operation must now be planned. With the plant currently in operation in the middle of an operating cycle, the work management process must be followed, which includes planning and selecting appropriate timeframes for activating the OPTS for each train. four work packages must be implemented, i.e., one for each feeder breaker trip circuit (as there are two feeder breakers, one normal and one alternate, for each of the two 4. 1 6-ky Class 1E safety buses at Callaway). In order to allow sufficient time to complete the work management process (as managed pursuant to 10 CFR 50.65(a)(4)), including release of the OPTS modification for operation, Ameren Missouri is extending the current implementation schedule, i.e., from the current end date of December 3 1 20 1 9 (as established in accordance with the industry/generic schedule of Reference 4) to a new end date of May 1 5, 2020.

This letter contains no new regulatory commitments.

If you have any questions about this submittal, please contact Roger C. Wink, Manager Regulatory Affairs at (573) 310-7025.

I declare under penalty ofperjury that the foregoing is true and correct.

Senior Director, Nuclear Operations Executed on: Dec. 10) 2O1

ULNRC-06554 December 10, 2019 Page 4 of 5 cc: Mr. Scott A. Morris 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. L. John Klos Project Manager, Callaway Plant Office ofNuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 09E3 Washington, DC 20555-0001

ULNRC-06554 December 10, 2019 Page 5 of 5 Index and send hardcopy to QA File A160.0761 Hardcopy:

Certrec Corporation 6 1 00 Western Place, Suite 1050 Fort Worth, TX 76107 (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 Other Situations ULNRC Distribution:

F. M. Diya T. E. Herrmann B. L. Cox F. J. Bianco S. P. Banker R. C. Wink T. B. Elwood Corporate Oversight NSRB Secretary STARS Regulatory Affairs Mr. Jay Silberg (Pillsbury Winthrop Shaw Pittman LLP)

Mr. Dan Beck (Missouri Public Service Commission)

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