Text

NRC Inspection of Temporary Instruction 2515/194, Inspection Report 05000483/2018011
	ML18289A652
Person / Time
Site:	Callaway
Issue date:	10/16/2018
From:	Greg Werner; NRC/RGN-IV/DRS/EB-2
To:	Diya F; Ameren Missouri
	Werner G
References
	IR 2018011
	Download: ML18289A652 (13)
	v • d • e

October 16, 2018

SUBJECT:

CALLAWAY PLANT, UNIT 1 - NRC INSPECTION OF TEMPORARY INSTRUCTION 2515/194, INSPECTION REPORT 05000483/2018011

Dear Mr. Diya:

On September 13, 2018, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at your Callaway Plant. On September 18, 2018, the inspector discussed the results of this inspection with Mr. Roger Wink, Regulatory Affairs Manager, and other members of your staff. The results of this inspection are documented in the enclosed report.

The NRC inspector did not identify any findings or violations of more than minor significance.

This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.

Sincerely,

/RA Gregory Pick Acting for/

Gregory E. Werner, Chief Engineering Branch 2 Division of Reactor Safety

Docket Nos. 50-483 License Nos. NPF-30

Enclosure:

Inspection Report 05000483/2018011 w/ Attachment: TI 2515/194 Inspection Documentation Request

Enclosure

U.S. NUCLEAR REGULATORY COMMISSION

Inspection Report

Docket Number(s):

05000483

License Number(s):

NPF-30

Report Number(s):

05000483/2018011

Enterprise Identifier: I-2018-011-0050

Licensee:

Union Electric Company

Facility:

Callaway Plant

Location:

Steedman, Missouri

Inspection Dates:

September 10, 2018, to September 13, 2018

Inspectors:

B. Correll, Reactor Inspector

Approved By:

Gregory E. Werner, Chief

Engineering Branch 2

Division of Reactor Safety

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring licensees performance by conducting Temporary Instruction 2515/194, Inspection of the Licensees Implementation of Industry Initiative Associated with the Open Phase Condition Design Vulnerabilities in Electric Power Systems (NRC Bulletin 2012-01), at Callaway Plant, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the Nuclear Regulatory Commission program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.

List of Findings and Violations

No findings were identified.

Additional Tracking Items

None.

INSPECTION SCOPE

This inspection was conducted using Temporary Instruction 2515/194 (ADAMS Accession No. ML17137A416), dated October 31, 2017. The inspectors reviewed the licensees implementation of Nuclear Energy Institute voluntary industry initiative in compliance with Commission guidance. The inspector discussed the licensees open phase condition system design and ongoing implementation plans with plant staff. The inspector reviewed licensee and vendor documentation, and performed system walk downs to verify that the installed equipment was supported by the design documentation. The inspector verified that the licensee had completed the installation and testing of equipment (with the exception of the tripping functions),installed and tested alarming circuits both local and in the control room, and analyzed potential impacts associated with the design implementation on the current licensing basis.

OTHER ACTIVITIES

- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL

Temporary Instruction 2515/194 - Inspection of the Licensees Implementation of Industry Initiative Associated With the Open Phase Condition Design Vulnerabilities in Electric Power Systems (NRC BULLETIN 2012-01)

The objective of Temporary Instruction 2515/194 is to verify that licensees have appropriately implemented the Nuclear Energy Institute voluntary industry initiative (ADAMS Accession No. ML15075A454), dated March 16, 2015, including updating their licensing basis to reflect the need to protect against open phase conditions.

Temporary Instruction 2515/194-03.01 - Voluntary Industry Initiative (Part 1)

Callaway Plant selected a hybrid design using safety-related negative sequence relays and the open phase detection system designed and manufactured by Power System Sentinel Technologies, LLC. At the end of this inspection the system was still in the monitoring mode of operation to facilitate continued data gathering of grid perturbations for evaluation of alarm and trip setpoints. The open phase condition equipment was installed on the safety-related 4160 Vac buses (NB01 and NB02), and the Power System Sentinel Technologies, LLC equipment installed on Safeguards Transformer A (XMDV24). The licensee is scheduled to transition the negative sequence relays to full implementation (tripping functions enabled) by December 31, 2018. The licensee was preparing associated documentation for this transition, however they were not available for review at the time of inspection.

INSPECTION RESULTS

- OBSERVATIONS/ASSESSMENT

Based on discussions with the licensee staff, review of available design, testing, grid data trending results documentation, and walk downs of installed equipment, the inspector had reasonable assurance the licensee appropriately implemented the voluntary industry initiative.

The inspector determined that:

Detection, Alarms, and General Criteria TI 2515/194-03.01 - Voluntary Industry Initiative (Part 1)

(1) Open phase conditions will be detected and alarmed in the control room for each unit on the common annunciator panel.

(2) Detection circuits will be sensitive enough to identify an open phase condition for all credited loading conditions.

(3) No Class-1E circuits were being replaced with non-Class 1E circuits in the design.

Protective Actions Criteria TI 2515/194-03.01 - Voluntary Industry Initiative (Part 1)

(1) One transformer was susceptible to an open phase condition and the licensee was implementing design changes to mitigate the effects.

(2) With an open phase condition present and no accident condition signal, the open phase design would not adversely affect the function of important-to-safety systems, structures, or components. The licensees open phase condition design solution added two safety-related negative sequence relays on the safety-related 4160 Vac buses, and a Power System Sentinel Technologies system on the Safeguards B transformer for alarm only. This addition added a new tripping condition (open phase) to safety-related bus incoming supply breakers. The credited plant response was unaffected and would be the same regardless of the conditions that generated the isolation of the transformer.

No findings were identified.

The inspector identified the following exceptions to the Temporary Instruction criteria resulting from the incomplete design modifications:

Detection, Alarms and General Criteria Exceptions TI 2515/194-03.01 - Voluntary Industry Initiative (Part 1)

(1) The licensees design was operating in the monitoring mode with established setpoints enabled to gather data to ensure the open phase condition design and protective schemes would minimize misoperation, or spurious actions in the range of voltage unbalance normally expected in the transmission system. Because actual demonstration of this criterion requires the system to be in operation with final trip setpoints established, the inspector was not able to fully verify this criterion. After discussions with licensee staff, design document and test results reviews, the inspector had reasonable assurance that the actuation circuit design would not result in lower overall plant reliability. The inspector did not identify any issues of concern.

(2) The Final Safety Analysis Report (FSAR) had not been updated to include information related to open phase conditions at the conclusion of the onsite inspection. The licensee provided the inspector with proposed changes to the licensing basis that discussed the system requirements related to the effects of, and protection for, any open phase condition design vulnerability. The licensee continued to modify and update the proposed changes during the onsite portion of the inspection. The inspector verified the proposed change process is being tracked under License Document Change Notice, LDCN 17-0012 for the completion of the FSAR updates.

The inspector did not identify any issues of concern.

Protective Actions Criteria Exceptions TI 2515/194-03.01 - Voluntary Industry Initiative (Part 1)

(1) The licensees open phase condition design solution uses safety-related negative sequence relays on the 4160 Vac safety buses in a 2-out-of-2 coincidence logic for protection. A voltage unbalance of sufficient magnitude will actuate both negative sequence relays. The relays are designed to trip open the normal and alternate supply breakers to the associated safety bus, causing a loss of voltage to the bus.

The existing undervoltage relays will operate as designed to initiate starting of the emergency diesel generator to restore power to the bus.

The tripping function of the incoming breakers remained disabled during the onsite portion of the inspection and was not able to be demonstrated to perform the designed function. This action was being tracked in the modification package MP 15-0008.

Through review of design documents and discussions with licensee staff, the inspector had reasonable assurance that with an open phase condition present and with and without an accident condition signal, the open phase design would isolate the affected bus and cause an automatic restoration of power from the emergency diesel generators. Due to the configuration of Callaway Plants electrical distribution system, a loss of phase on one transformer would only affect one train of equipment, and loads required to mitigate postulated accidents would be available on the non-affected train, ensuring that safety functions are preserved as required by the current licensing bases. The inspector did not identify any issues of significance.

(2) At the time of this inspection, the licensee had not finalized documentation for periodic tests, calibrations, setpoint verifications, or inspection procedures associated with the Power System Sentinel Technologies, LLC at the time of this inspection. This action was being tracked in the modification package MP 15-0008. The inspector held discussions with licensee staff and identified that plans were in place to establish contracts with the vendor to provide maintenance and support activities for the Power System Sentinel Technologies, LLC equipment.

The licensee established maintenance activities for the safety-related portion of the open phase condition design, and the inspector verified the activities were appropriate.

Existing plant equipment will continue to be maintained according to the licensees current preventative maintenance program. The inspector did not identify any issues of concern.

EXIT MEETINGS AND DEBRIEFS

On September 18, 2018, the inspector conducted a telephonic exit to present the Temporary Instruction 2515/194 inspection results to Mr. R. Wink, Regulatory Affairs Manager, and other members of the licensee staff. The inspector verified no proprietary information was retained.

DOCUMENTS REVIEWED

Inspection Procedure TI 2515/194

Condition Reports

201707350

201707586

201802205

201802672

Drawings

Number

Title

Revision

8618-X-94076

Metering and Relaying 345-13.8KV Safeguard

Transformers POSN-V22 and V24

8618-X-94091

345-13.8KV SFGD XFMR-B AC Portion

8618-X-94726

Annunciator -1 Sheet -2 Drop -51 Thru 96, 98, & 100 18

8618-X-94760

Alarms and Metering to Plant Unit-1 ANN., BOP

Computer and Site Related Panel

8618-X-95741

345-13.8KV SFGD XFMR-B DC Portion

E-21001

Main Single Line Diagram

E-21023

Relay Setting Tabulations and Coordination Curves

System NB

E-21NB01