IR 05000413/2019011

Temporary Instruction 2515/194 Open Phase Condition Report 05000413/2019011 and 05000414/2019011

ML19205A317
Person / Time
Site:	Catawba
Issue date:	07/24/2019
From:	Christopher Even NRC/RGN-II
To:	Simril R Duke Energy Carolinas
Reeder D
References
IR 2019011
Download: ML19205A317 (5)

Text

uly 24, 2019

SUBJECT:

CATAWBA NUCLEAR STATION - TEMPORARY INSTRUCTION 2515/194 OPEN PHASE CONDITION REPORT 05000413/2019011 AND 05000414/2019011

Dear Mr. Simril:

On June 12, 2019, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at your Catawba Nuclear Station Units 1 and 2 and discussed the results of this inspection with Mr.

Clark Curry and other members of your staff. The results of this inspection are documented in the enclosed report.

The NRC inspectors did not identify any finding or violation 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/

Christopher J. Even, Chief (Acting)

Construction Inspection Branch 2 Division of Construction Oversight Docket Nos.: 05000413 and 05000414 License Nos.: NPF-35 and NPF-52

Enclosure:

As stated

Inspection Report

Docket Numbers: 05000413 and 05000414 License Numbers: NPF-35 and NPF-52 Report Numbers: 05000413/2019011 and 05000414/2019011 Enterprise Identifier: I-2019-011-0039 Licensee: Duke Energy Carolinas, LLC Facility: Catawba Nuclear Station Location: York, SC 29745 Inspection Dates: June 10, 2019 to June 12, 2019 Inspectors: J. Kent, Construction Inspector Approved By: Christopher J. Even, Chief (Acting)

Construction Inspection Branch 2 Division of Construction Oversight Enclosure

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a Temporary Instruction 2515/194 Open Phase Condition inspection at Catawba Nuclear Station in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs 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 or violations of more than minor significance were identified.

INSPECTION SCOPE

Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.

OTHER ACTIVITIES

- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL 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)

This inspection was conducted using Temporary Instruction (TI) 2515/194 (ADAMS Accession No. ML17137A416), dated October 31, 2017. The inspectors reviewed the licensees implementation of Nuclear Energy Institute voluntary industry initiative (VII) in compliance with Commission guidance. The inspectors discussed the licensees open phase condition (OPC)system design and ongoing implementation plans with plant staff. The inspectors reviewed licensee documentation, vendor documentation, and performed system walkdowns to determine if the installed equipment was supported by the design documentation. These reviews were also made to determine if the licensee had completed the installation and testing of equipment, installed and tested alarming circuits both locally and in the control room, and analyzed potential impacts associated with the design implementation on the current licensing basis.

The objective of TI 2515/194 was to verify that licensees had appropriately implemented the NEI VII (ADAMS Accession No. ML15075A454), dated March 16, 2015, including updating their licensing basis to reflect the need to protect against OPCs.

Inspection of the Licensees Implementation of Industry Initiative Associated With the Open Phase Condition Design Vulnerabilities In Electric Power Systems (NRC Bulletin 2012-01) (1 Sample)

Temporary Instruction 2515/194-03.01 - VII (Part 1)

Catawba Nuclear Station selected the open phase detection system designed and manufactured by Power System Sentinel Technologies, LLC. At the end of this inspection the system remained in the monitoring mode of operation to facilitate continued data gathering of the system for evaluation of alarm and trip setpoints. The equipment was installed on the main step-up transformers (MSU) 1A, 1B, 2A, and 2B. Catawba Nuclear Station currently has no set scheduled date to transition the open phase detection system to full implementation (tripping functions enabled).

INSPECTION RESULTS

Assessment 2515/194 Detection, Alarms, and General Criteria - TI 2515/194-03.01 - VII (Part 1)

Based on discussions with the licensee staff, review of available design, testing, grid data trending results documentation, and walkdowns of installed equipment, the inspectors had reasonable assurance the licensee appropriately implemented the VII.

The inspectors determined that:

(1) OPCs will be detected and alarmed in the control room on the common annunciator panel.

(2) Detection circuits will be sensitive enough to identify an OPC for all credited loading conditions for installed equipment.

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

(4) The Updated Final Safety Analysis Report (UFSAR) has been updated to discuss the design features and analyses related to the effects of, and protection for, any OPC design vulnerability.

Assessment 2515/194 Protective Actions Criteria - TI 2515/194-03.01 - VII (Part 1)

(1) Four transformers were susceptible to an OPC as identified in this VII when the main generator was offline. The licensee installed detection and mitigating equipment for these affected transformers.

(2) With an OPC present and with or without an accident condition signal, the open phase design would not adversely affect the function of important-to-safety systems, structures, or components. The licensees OPC design solution added Power System Sentinel Technologies, LLC systems on the main step-up transformers MSU 1A, 1B, 2A, and 2B. The tripping function, when enabled, will provide an additional input to the associated transformer lockout relays. The credited plant response is not negatively affected and will be the same regardless of the conditions that generated the lockout of the transformer.

Assessment 2515/194 Detection, Alarms, and General Criteria Exceptions - TI 2515/194-03.01 - VII (Part 1)

The inspectors identified the following minor exceptions to the Temporary Instruction criteria resulting from the operating status of the design modifications.

(1) The licensees design was operating in the monitoring mode with already established setpoints and gathering data to verify the OPC design and protective schemes would minimize mis-operation, or spurious actions in the range of voltage unbalance normally experienced in the transmission system. The licensee developed engineering calculations to demonstrate coordination of the OPC detection and tripping setpoints for the actuation circuit that does not result in lower overall plant operation reliability. This calculation was presented in CNC-1381.06-00-0080, Rev. 0 and CNC-1381.06-00-0081, Rev. 0, for Units 1 and 2, respectively.

(2) A draft of the UFSAR was available for the inspectors review that included information related to OPCs. The licensee provided the inspectors with proposed changes to the licensing basis that discussed the system requirements related to the effects of, and protection for, any OPC design vulnerability. The inspectors verified the proposed change process was being tracked under initiating document EC 0000401499, OPEN PHASE DETECTION U1, Rev. 000 & EC 0000402827, OPEN PHASE DETECTION U2, Rev. 000.

The inspectors also determined that the Technical Specification Bases was not affected by this VII as evaluated under AR 02170349 and AR 02114867 for Units 1 and 2, respectively.

Assessment 2515/194 Protective Actions Criteria Exceptions - TI 2515/194-03.01 - VII (Part 1)

The inspectors identified the following minor exceptions to the Temporary Instruction criteria resulting from the operating status of the design modifications.

The licensees OPC design solution uses Power System Sentinel Technologies, LLC to detect, alarm, and provide an input to the associated MSU zone lockout relays. Upon an initiation of the zone lockout relays, the zone that is affected by a power loss is tripped and isolated.

The tripping function input to the transformer lockout relays remained deactivated during the onsite system implementation inspection and was not able to be demonstrated to perform the designed function. This action was being tracked in the design change package EC 0000401499 & EC 0000402827. Once enabled, the Open Phase Protection system will have the ability to isolate an affected MSU with an OPC detected on the high voltage side of the MSUs when either the Generator Power Circuit Breakers (GPCB) or at least one of the two no-load motor operated disconnects for physical break isolation of the GPCB are opened.

Due to the configuration of Catawba Nuclear Station 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.

Periodic tests, calibrations, setpoint verifications or inspections (as applicable) have been established for any new protective features. The surveillance requirements have been maintained for the plant Technical Specifications in compliance with the provisions of 10 CFR 50.36. Existing plant equipment will continue to be maintained according to the licensees current preventative maintenance program.

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

• On June 12, 2019, the inspectors presented the Temporary Instruction 2515/194 Open Phase Condition results to Mr. Clark Curry and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

2515/194 Calculations CNC-1381.06-00-0032 023

CNC-1381.06-00-0080 000

CNC-1381.06-00-0081 000

Drawings CN-1700-02.01 VTO ONE LINE DIAGRAM 22 KV RELAYS & 009B

METERS TRANSFORMERS N

O. 1A, 1T1A, 1T2A &

1ATE

CN-1700-03.01 VTO ONE LINE DIAGRAM 22 KV RELAYS & 010A

METERS TRANSFORMERS N

O. 1B, 1T1B & 1T2B

CN-1701-04 LOGIC DIAGRAM UNIT MAIN PWR SYS 007

PROTECTIVE RELAYING ZONE 1B PRIMARY &

BACKUP

CN-2700-02.01 VTO ONE LINE DIAGRAM 22KV RELAYS & 008A

METERS TRANSFORMER N

O. 2A, 2T1A 2T2A &

2ATE

CNEE-0186-01.01 ELEMENTARY DIAGRAM UNIT MAIN POWER 008B

SYS RELAYING NEUTRAL OVERCURRENT

RELAYS ZONE 1A

CNEE-0198-01 ELEMENTARY DIAGRAM TRANSFORMER 1A 005A

MONITORING

CNM 1330.05-0101 PSSTech Open Phase Protection (OPP) System- 000

MSU 1A Ch 1 Electrical Drawings

CNM 1330.05-0103 PSSTech Open Phase Protection (OPP) System- 000

MSU 1A Elementary Drawings

CNM 1330.05-0110 PSSTech Open Phase Protection (OPP) System- 000

MSU 1B Ch 1 Electrical Drawings

SK-EC410663-1000 Sheet Open Phase Protection System Main Step Up A

Transformer 1A Conduit Route Plan

SK-EC410663-3000 Sheet Open Phase Protection System Main Step Up A

Transformer 1A Power & Control Block Diagram

Engineering 0000401499 OPEN PHASE DETECTION U1 00

Changes 0000402827 OPEN PHASE DETECTION U2 00

Engineering AR 02114867 Open Phase Detection U2 00

Inspection Type Designation Description or Title Revision or

Procedure Date

Evaluations AR 02170349 Open Phase Detection U1 00

Miscellaneous IEGR-MN-2007 Open Phase Protection (OPP) System Preventative 11/12/2018

Maintenance Guide

PSSTech/OPPsys/Analysis- Open Phase Protection (OPP) System: Analysis of 2015

-2015/0225-200 Open Phase Protection (OPP) System Impact on

Existing Power System

UFSAR Chapter 8 20

UFSAR Changes UFSAR Change for EC 402827 00

Procedures OP/0/A/6350/010 Operation of Station Breakers and Disconnects 101

OP/1/A/6350/001 Normal Power Checklist 085

OP/1/B/6100/010 L Annunciator Response for Panel 1AD-11 063

OP/1/B/6300/001 Turbine Generator 109

OP/2/A/6350/001 Normal Power Checklist 083

OP/2/B/6100/010 L Annunciator Response for Panel 2AD-11 062

OP/2/B/6300/001 Turbine Generator 092

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