ML20160A053

Digital Modernization Project LAR - Presubmittal Meeting - NRC Presubmittal Meeting Telecon June 12, 2020

ML20160A053
Person / Time
Site:	Limerick
Issue date:	06/08/2020
From:	Exelon Corp
To:	Office of Nuclear Reactor Regulation
Marshall M, NRR/DORL/LPL, 415-2871
References
EPID L-2020-LRM-0041
Download: ML20160A053 (32)

Text

Limerick Generating Station Digital Modernization Project LAR Presubmittal Meeting NRC Presubmittal Meeting Telecon June 12, 2020

Agenda / Opening Remarks

• Introductions

• Expected outcome for meeting

• Fee Waiver

• Project description

• Current and Proposed Architecture

• Use of Alternate Review Process (ARP)

• NRC Lessons learned - digital projects

• Closing Remarks 1

Introductions - Project Team

• Susan Korn, VP Project Management

• Steve Hesse, Project Director

• Jerry Segner, Principal Project Manager

• Shannon Rafferty-Czincila, Licensing Director

• Dave Helker, Licensing Manager

• Frank Mascitelli, Licensing Lead

• Bob Dickinson, LGS Regulatory Assurance Manager

• George Budock, LGS Regulatory Assurance

• Pareez Golub, Digital Licensing SME

• Craig Myers, LGS Operations

• Sagar Patel LGS Operations 2

Introductions - Engineering

• Elliott Flick, VP Centralized Design Organization

• Vikram Shah, Director CDO

• John Connelly, I&C Analytical Branch Manager

• Mark Samselski, Lead Responsible Engineer

• George Bonanni, I&C Responsible Engineer

• Scott Schumacher, Systems Engineering

• Farad Zaman, Systems Engineering 3

Expected Outcome of Meeting

• NRC has an overview of project scope

• NRC has understanding of the current project milestones

• Exelon gains insights on NRC lessons learned from previous digital License Amendment Requests (LAR) 4

Exelon - DOE Partnership

• Historically, industry has struggled with modernization of first-echelon safety systems

• NRC issuance of Digital Instrumentation and Controls Interim Staff Guidance #06 (DI&C-ISG-06), Revision 2, Licensing Process, addressed perceived regulatory barriers

• In 2019 a public / private partnership was formed through the Light Water Reactor Sustainability Program (LWRS) to research viability of modernization of safety systems 5

Exelon - DOE Partnership

• Research produced two key products - Technical Requirements Specification (TRS) and License Amendment Request framework document

• LAR Framework Document

- Vendor-independent LAR framework document created in a format consistent with the DI&C-ISG-06 ARP

- Document is a starting point and will be refined as Limericks design further matures

- LAR framework will be made available through LWRS as a starting point for other licensees 6

Intent to Request NRC Fee Waiver

• Request fee waiver under 10 CFR 170.11(b)

• LAR will exercise all portions of the DI&C-ISG-06 Alternate Review Process for a large-scale protection system replacement

• Learnings from LGS execution of ARP will be used to support US operating fleet digital protection system modernization efforts

• First-echelon safety system digitization is critical to US operating fleet sustainability 7

Intent to Request NRC Fee Waiver

• LAR will utilize standardized industry digital design guidance - pilot project for Exelon

• EPRI Digital Engineering Guide (DEG) and

• NISP-EN-04, Standard Digital Engineering Process

• NEI 06-04, License Amendment Request Guidance, Appendices F and G

• DOE LWRS research LAR Framework Document subsequent revisions

• LGS LAR will set precedent for US operating fleet protection system modernization 8

Intent to Request NRC Fee Waiver DI&C-ISG-06 R2, Enclosure B, Information Provided in Support of a License Amendment Request for a Digital Instrumentation and Control Modification 9

Project Overview 10

Project Scope Replacement of first-echelon Safety-related Systems:

• Reactor Protection System (RPS)

• Nuclear Steam Supply Shutoff System (NSSSS)

• Emergency Core Cooling System (ECCS)

Project scope is draft for NRC discussion and planning purposes. Final scope to be determined by Exelon by August 2020.

11

Project Benefits

• Increase in plant safety

• Reduction in human error potential

• Increase in operational decision-making accuracy and speed

• Higher full system availability

• Enhanced self-diagnostic capabilities

• Increase in reliability

• Elimination of spurious half scrams

• Elimination of single component vulnerabilities

• Reduction of obsolete components

• Elimination of 1800 safety significant components 12

Project Benefits

• Increase in quality Operations and Maintenance

• Improved availability, spectrum and quality of MCR information

• Improved configuration control

• Continuous self-testing and diagnostics of all trains of safety functions

• Reduced administrative overhead

• Reduced operator burden through automation

• Supports workforce of the future 13

Project Milestones

• NRC presubmittal meeting June 2020

• Vendor selection July 2020

• Letter of Intent July 2020

• Fee waiver request letter July 2020

• Next NRC presubmittal mtg Oct 2020

• PPS LAR submittal June 2021 14

Current Architecture 15

Current Architecture - Main Control Room U1 - 647 -HPCI, 648 U2 - 603 Mode Switch

-RICI, 601 and Rx Scram Buttons Reactor/Containment Console Cooling and Isolation Vertical Boards U1 - 603 Mode U2 - 647 -HPCI, 648 -

Switch and Rx RICI, 601 Scram Buttons Reactor/Containment Console Cooling and Isolation Vertical Boards Unit 1 Unit 2 16

Current Architecture - Auxiliary Equipment Room C611 C611 C633 C633 C618 C646 C623 C618 C646 C623 C641 C641 C613 C613 C620 C620 C644 C644 C622 C622 C631 C609 C631 C609 C628 C628 C621 C621 C640 C640 C617 C617 Unit 1 Unit 2

Current Architecture - RPS, NSSSS, ECCS

• Commonalities between systems

• Detector trip unit relay

• Operator interface in Main Control Room

• Logic resides in Aux Equipment Room

• Up to 8 instrument channels to support 4 divisions of logic

• Each system installed separately

• Cohabitation of some logic and detector signals 18

Current Architecture - RPS

• RPS

• NSSSS

Purpose:

cause rapid *

Purpose:

Isolate plant shutdown primary containment

• Logic

• Logic

-Each division has two -One or two channels channels per division

-Two divisions -Up to four divisions

-One out of two taken -Variable, purpose twice specific logic

-Fail safe -Fail safe

• Two safeguard power -Interposing relays supplies

• Two safeguard power supplies 19

Current Architecture - ECCS

• From left to right

• Automatic Depressurization System (ADS)

• Core Spray (CS) Div. 1 and 3

• Residual Heat Removal System (RHR) Divisions 1 and 3

• NSSSS interface

• Core Spray Divisions 2 and 4

• RHR Divisions 2 and 4

• Reactor Core Isolation Cooling (RCIC) System

• High Pressure Core 20 Injection (HPCI) System

Current Architecture - ECCS

• Two instrument channels per division Divisions 1 & 3 ECCS in

• All use 1 out of 2 logic AER

• HPCI and RCIC are single division to initiate, two divisions for isolation

• ADS is two divisions

• Four divisions of Low Pressure Injection

• Divisional Diesel backed safeguard power

• Divisional AC and safeguard battery control power 21

Proposed Architecture 22

Proposed Architecture - Plant Protection System (PPS)

• New system comprised of vendors standard platform

• Vendor platform will have prior NRC approval

• New system retains similar architecture

• Replaces the existing four divisions of bi-stable analog trip units in RPS, NSSSS, and ECCS with separate, independent, channel functions in application software

• RPS, NSSSS, and ECCS are designed as segmented functions, running on a common platform

• Functions retain their existing logic separation

• Clear differentiation between channels, electrical divisions, and mechanical trains Digital platform vendor selection in progress 23

Current vs. Proposed Architecture - Main Control Room

• MCR Human Machine Interface (HMI) will be video display units (VDUs)

• Eliminate the separate lamp-based trip, status, and bypass indicators (BISI) and provide the information on the VDUs.

• Select manual controls are retained (e.g., Reactor SCRAM) with soft controls added for division-level systems initiation and component control 24

Current vs. Proposed Architecture - Auxiliary Equipment Room To Main To Video Main To Control Video Displa Video Displa To Control Main y To MainVideo Control Room Main Display Room Display Room Control y Control Room Room 25

Proposed Architecture - Plant Protection System (PPS)

• One-way redundant fiber optic cabling from each safety channel and safety division to the non-safety related DCS data backbone, which allows diverse display of all RPS, NSSSS, ECCS data and status by DCS/Plant Process Computer displays and annunciation.

• Ability to bypass one of the four channels for maintenance, while still retaining 2 out of 3 twice voting in the divisions

• Eliminate or reduction of Technical Specification (TS)

Surveillance Requirements (SR) through crediting platform and application self-diagnostics 26

Proposed Architecture - Plant Protection System (PPS)

• Use the existing, retained field input wiring terminals, hardwired connections to the new PPS (RPS, NSSSS, and ECCS) inputs and outputs

• To the extent practicable, eliminate redundant transmitters and bi-stables

• Ensure that the platform design does not preclude future migration of other safety systems and safety functions to the platform 27

LAR Use of Alternate Review Process (ARP) 28

Use of DI&C-ISG-06 Alternate Review Process

• Several presubmittal meetings to be planned to discuss full list of topics provided by NRC and included in DI&C-ISG-06

• Comprehensive Vendor Oversight Plan (VOP) will be developed for project - VOP Summary will be included in LAR

• NRC-approved platform used / applicability of application software development process (if NRC approved) to proposed software design, implementation, and test

• Regulatory commitments provided for:

• For uncompleted Plant Specific Action Items (PSAIs) included in LAR

• For later lifecycle design activities not governed by other regulatory processes 29

Next Presubmittal Meeting Topics

• Key design concepts, including the four fundamental design principles

• Replacement modification scope

• Comparison of the existing architecture and the proposed architecture

• D3 assessment strategy

• Identified significant deviations from a referenced NRC-approved topical report (if applicable)

• Strategy for changing TS SRs based on self-diagnostics

• Impact on Accident Analyses (e.g. response time testing)

• Human Factors considerations 30

NRC Lessons Learned Digital Projects 31