ML19329C587
| ML19329C587 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/25/2019 |
| From: | Alexander Schwab NRC/NRR/DRA/APOB |
| To: | Bryan Hanson Exelon Generation Co, Exelon Nuclear |
| References | |
| NEI 19-02 | |
| Download: ML19329C587 (5) | |
Text
November 25, 2019 Mr. Bryan C. Hanson Senior Vice President, Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO), Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
R. E. GINNA NUCLEAR POWER PLANT REGULATORY AUDIT
SUMMARY
RE: CONFIRMATION OF A PLANTS IMPLEMENTATION OF NUCLEAR ENERGY INSTITUTE (NEI) 19-02, GUIDANCE FOR ASSESSING OPEN PHASE CONDITION IMPLEMENTATION USING RISK INSIGHTS
Dear Mr. Hanson:
This letter is being sent to document the results of an audit conducted by the U.S. Nuclear Regulatory Commission (NRC) at R.E. Ginna Nuclear Power Plant. The NRC conducted the audit according to the audit plan, Regulatory Audit in Support of Confirmation of a Plants Implementation of Nuclear Energy Institute (NEI) 19-02, Guidance for Assessing Open Phase Condition Implementation Using Risk Insights, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19281C941). Ginna has decided to use NEI 19-02 to risk-inform the decision of whether to implement the Open Phase Isolation System to provide alarm and indication to the control room operators as opposed to automatic actuation mode in response to an Open Phase Condition (OPC).
One of the purposes of the audit was to identify key areas to address in a revision to the Temporary Inspection (TI) on OPC response to accommodate a plant that chose to use NEI 19-02 to stay in alarm only mode to address an OPC. This was done by investigating whether Ginna appropriately implemented the guidance in NEI 19-02. The audit also helped to determine whether the implementation of NEI 19-02 could be an appropriate alternate approach consistent with the revised Voluntary Industry Initiative on OPC response. The audit took place from October 15th-October 18th, 2019. The audit team was comprised of a Reliability and Risk Analyst from NRC headquarters and a regional Senior Reactor Analyst.
The audit began on October 15th, 2019, with an entrance meeting between the NRC and the licensee's staff and contractors. During the audit, the NRC participated in a technical review according to the audit plan. This technical review focused on how the methodology described in NEI 19-02 was implemented and the application (or temporary changes) of the plant specific PRA model of record within the context of applying the 19-02 methodology. It also included reviewing the training conducted and procedures required to address OPC to help verify the Human Reliability Analysis (HRA) documented in the licensees assessment, as well as reviewing the supporting documentation behind other key assumptions described in the licensees assessment and PRA model.
B. Hanson On October 18th, 2018, at the conclusion of the audit, the NRC participated in an exit meeting with the licensee's staff. During the exit, the NRC discussed recommendations that it would be incorporating into the revision of the TI. The recommendations included:
inspectors reviewing the training, procedures, and operator actions, and ensuring the HRA described in NEI 19-02 matches the inspectors observations. The team also identified a procedural weakness during the simulator demonstration: it was possible for an OPC alarm at certain locations (i.e., 2 of the 5 modified transformers), but not be directly confirmed by the procedure, thereby increasing the time before fault identification and isolation. It was noted, however, that OPC faults occurring in either of these locations was unlikely, and if one did, the overall effect was captured by a sensitivity study which increased the human error probabilities associated with the human actions assessed in the HRA. The team noted this was a valuable lesson learned for plants and that the revised TI would include guidance to verify that the plant procedures have indication checks for OPC faults at all locations. The team also suggested that for future NEI 19-02 analyses, for Ginna and other plants, sensitivity analysis be conducted for risk significant OPC electrical maintenance lineups. For example, Ginna can go into offsite power configurations (mode 0-100 or 100-0) where one station auxiliary transformer supplies all the safety buses during maintenance.
The team noted there was no Technical Specifications or the Technical Requirements Manual limitations on these configurations, thus sensitivity analyses of these alignments would be beneficial. The licensee performed a sensitivity analysis during the audit for these configurations. The analysis used a realistic time estimates based on past durations in these lineups and demonstrated there was no impact on the established 1E-6/year Core Damage Frequency threshold. The team concluded that the audit did not identify any issues that would preclude NEI 19-02 from being an appropriate alternate approach consistent with the revised OPC Voluntary Industry Initiative.
contains a list of documents reviewed by the team during the audit.
If you have any questions, please contact me at 301-415-8539 or via e-mail at Alexander.Schwab@nrc.gov.
Sincerely
/RA/
Alexander H. Schwab, Reliability and Risk Analyst PRA Oversight Branch Division of Risk Assessment Office of Nuclear Reactor Regulation
Enclosures:
- 1. List of Participants
- 2. List of Documents Reviewed cc: Listserv
LIST OF PARTICIPANTS U.S. NUCLEAR REGULATORY COMMISSION (NRC} AUDIT TEAM Alexander Schwab NRC/Audit Lead Frank Arner NRC/Senior Reactor Analyst
LIST OF DOCUMENTS REVIEWED DURING THE AUDIT The following documents were reviewed by the U.S. Nuclear Regulatory Commission audit team during the audit. The documents generally included procedures that implement the actions described in response to an Open Phase Condition (OPC) with the alarm in manual, the training on these procedures, the plants Nuclear Energy Institute (NEI) 19-02 analysis, and other documentation verifying the assumptions used in the NEI 19-02 analysis.
NEI 19-02, Guidance for Assessing Open Phase Condition Implementation Using Risk Insights G1-MISC-018, Ginna Open Phase Condition Evaluation OPC Ops Training Summary 9-20 AR-PPCS-12AOPD, Rev-002, 12A Open Phase Detection AR-PPCS-12AOPDST, Rev-003, 12A OPC Relay Trouble AR-PPCS-12BOPD, Rev-002, 12B Open Phase Detection AR-PPCS-12BOPDST, Rev-002, 12B OPC Relay Trouble AR-PPCS-6T767OPD, Rev-003, 6T767 Open Phase Detection AR-PPCS-6T767OST, Rev-001, 6T767 OPC Relay Trouble AR-PPCS-7TOPD, Rev-002, 7T Open Phase Detection AR-PPCS-7TOPDST, Rev-003, 7T OPC Relay Trouble DA-EE-14-002, Ginna Offsite Power System Open Phase LOCA Analysis
SUBJECT:
R. E. GINNA NUCLEAR POWER PLANT REGULATORY AUDIT
SUMMARY
RE:
CONFIRMATION OF A PLANTS IMPLEMENTATION OF NUCLEAR ENERGY INSTITUTE (NEI) 19-02, GUIDANCE FOR ASSESSING OPEN PHASE CONDITION IMPLEMENTATION USING RISK INSIGHTS DATED: 11/25/2019 DISTRIBUTION:
PUBLIC PM File Copy RidsNrrDraApob Resource RidsNrrDeEeob Resource ASchwab, NRR/DRA/APOB AZoulis, NRR/DRA/APOB FArner, RI/DRS ADAMS Accession No.: ML19329C587
- via email OFFICE NRR/DRA/APOB NRR/DRA/APOB*
NAME ASchwab AZoulis DATE 11/25/2019 11/21/2019