Current Digital Instrumentation and Control Licensing Activities

1
Current Digital Instrumentation and Control
Licensing Activities
The 21st IAEA Meeting of Technical Working Group
on Nuclear Power Plant Control and
Instrumentation (TWG-NPPCI) May 23 25, 2007

• Ian Jung, Chief
• Instrumentation, Controls, and Electrical
  Engineering Branch
• Division of Engineering
• Office of New Reactors

2
Agenda

• Overview
• Summary of New Reactors and Digital
  Instrumentation and Control (IC)
• Status of Operating Reactor Digital IC Upgrades
• Key Technical Issues
• Challenges
• Moving Forward

3
Overview

• New reactors are a reality, and digital IC is
  integral to all designs
• Digital upgrades to operating plants safety IC
  systems are being proposed
• USNRC and stakeholders are working cooperatively
  on key issues
• USNRC is getting ready to handle upcoming wave of
  new reactor applications and upgrades

4
New Reactors
5
New Reactor Designs and IC

• ESBWR
• GE NUMAC and GE/INVENSYS TRICON digital IC
  platforms for RPS and ESFAS, respectively
• Staff IC review of design certification
  application and topical reports underway
• ABWR
• Digital IC architecture yet to be identified
• AP1000
• Westinghouse Common-Q digital IC platform for
  RPS/ESFAS
• Staff IC review of pre-application topical
  reports underway
• US-EPR
• TELEPERM XS digital IC platform for RPS/ESFAS
• Staff IC review of pre-application topical
  reports underway
• US-APWR
• Mitsubishi MELTAC platform for RPS/ESFAS
• Staff IC review of pre-application topical
  reports just begun

6
New Reactors and Diversity
7
New Reactor Digital IC Observations

• Tendency of a conservative approach
• Lack of operating experience
• Increase in regulatory acceptance probability
• Use of previously NRC-approved platforms
• TELEPERM XS, TRICON/NUMAC, and Common Q
• Reduction in regulatory review
• Five different designs
• Staff burden for learning and consistency

8
Status of Operating Reactor Upgrades

• Upgrades in non-safety related equipment (and
  some safety-related) have been active for years
• Obsolescence of analog equipment is becoming a
  big issue for industry
• License renewal is a factor
• Industry has begun to engage USNRC for major
  RPS/ESFAS digital IC upgrades
• Many plants are observing recent developments

9
Key Technical Issue Areas

• Cyber Security
• Diversity and Defense-in-Depth
• Risk-Informed Digital IC
• Highly Integrated Control Room Communications
• Highly Integrated Control Room Human Factors

10
Key IssuesCyber Security

• Consistencies within existing NRC and industry
  cyber security documents
• Regulatory Guide 1.152, Revision 2
• NEI 04-04, Revision 1
• Proposed rule change to 10 CFR 73.55 that
  includes provisions for cyber security of
  critical digital systems

11
Key Issues Diversity and Defense-in-Depth

• Determining what constitutes adequate diversity
  and defense-in-depth
• Use of operator action and acceptable operator
  action time
• Crediting leak detection as part of the coping
  strategy
• Considering the effects of common cause failures
  (CCFs) versus disable a safety function
• Design attributes that eliminate the need for
  consideration of CCFs

12
Key Issues Risk-Informed Digital IC

• Use of current methods to model digital systems
• Use of risk insights in the resolution of key
  digital system issues

13
Key Issues Highly Integrated Control Room
Communications

• Clarity in inter-divisional communications
  independence within digital systems
• Degree of independence necessary to retain the
  capability to accomplish the safety function

14
Key Issues Highly Integrated Control Room
Human Factors

• Minimum inventory for alarms, controls, and
  displays
• Guidance and criteria for review of procedures,
  e.g., computerized procedures
• Guidance for review of soft controls

15
Digital IC Steering Committee
PM Support
Task Working Groups (TWGs)
NRC Line Organizations
Industry Contacts
16
Challenges

• Addressing key issues in a timely manner to
  minimize impact on current or planned reviews and
  to support industry needs
• Achieving appropriate staffing, knowledge
  transfer, training and qualification
• Learning and using relevant operating experience
  and lessons worldwide in a practical way
• Balancing safety and schedule

17
Moving Forward

• USNRC to work closely with key stakeholders to
  address key high-priority issues in a timely
  manner
• USNRC to continue to recruit right people, to
  train and qualify existing and new employees, and
  to manage knowledge required for effective
  licensing reviews
• USNRC to engage with international community and
  other industries to gain relevant operating
  experience and to cooperate future activities in
  digital IC
• USNRC to ensure safety in digital IC while
  addressing schedule challenges