ML17240A338
| ML17240A338 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 08/30/2017 |
| From: | Northern States Power Co, Xcel Energy |
| To: | Robert Kuntz Plant Licensing Branch III |
| Kuntz R, NRR/DORL/LPLIII | |
| References | |
| Download: ML17240A338 (31) | |
Text
1 Non-Safety Related Digital Feedwater and AMSAC/DSS Control Systems Replacement Project Xcel Energy Prairie Island Nuclear Generating Plant 8-30-2017 1
2 Agenda
- Introductions
- Meeting Purpose
- Project Overview
- 10 CFR 50.59 Assessment
- Future Actions
- Summary
- Feedback and Questions 2
3 Meeting Purpose
- Outline project scope, design, and licensing basis supporting the digital FW and AMSAC/DSS control system change
- Discuss the preliminary 10 CFR 50.59 assessments and conclusions
- Discuss possible future interaction with the NRC staff 3
4 Project Overview
- Current System
- Westinghouse WDPF System
- Digital Technology
- Non-Safety Related Distributed Control System (DCS) 4
5 Project Overview
- Project Drivers
- Obsolescence
- WDPF Systems are 28 years old
- Parts not manufactured since 2002
- Vendor technical support ends in 2017
- Recent Hardware Issues
- Current system not suitable for plant life
- Unit 1 operation to 2033
- Unit 2 operation to 2034
- Long term operating and maintenance strategy
- Common platform with demonstrated history of reliable operation 5
6 Project Overview
- Timeline
- 2015-2016: Preliminary Engineering Phase
- Multidiscipline team
- Many team members from original WDPF team
- 2017: 10 CFR 50.59 Assessment Phase
- 2018: Detailed Design Phase
- 2019-2020: Installation Phase
- In service dates:
- Unit 2 - 2019
- Unit 1 - 2020 6
7 Project Overview
- Project Scope
- Replace existing DCS
- Digital to digital - Ovation
- WDPF to Ovation
- Next generation of platform
- Same OEM
- Upgrade FW Reg Valve Controls
- Analog to digital - DVC 7
8 Project Overview
- Project Design Principles
- Mitigate obsolescence
- Improve equipment reliability
- Eliminate SPVs and transient initiators
- Use well vetted, common platform with demonstrated history
- Design system hardware and software within the bounds of current design and licensing basis
- Use industry standard methods for design and testing
- Use a multi-layer testing approach through fabrication, installation, and commissioning
- Design, test, and install system to minimize outage impact 8
99 Project Overview
10 Project Overview
- Project Scope Detail
- Install Ovation DCS:
- FW Control System (SGWLC)
- AMSAC/DSS System
- Control System Infrastructure
- Modify Main Control Board Operator Interface:
- Retain operator manual controls
- Move some indications to new graphic display
- Modify FW Control Valve field devices:
- Replace FW Reg valve controls with dual redundant digital positioners on Main Control Valves and single digital positioner on Bypass Control Valves
- Modify Simulator 10
11 Project Overview
- Project Scope Detail (contd)
- Improve Equipment Reliability
- Increase redundancy
- Eliminate at least 16 SPVs (8 per unit)
- Functional Control Enhancements
- Reduce operator burden
- More fault tolerant
- Improve FW Control strategies
- Improve time response 11
12 10 CFR 50.59 Assessment
- FW Design & Licensing Basis
- AMSAC/DSS Design & Licensing Basis
- Assessment Approach
- Qualitative Assessment
- 10 CFR 50.59 Criteria
- Preliminary 10 CFR 50.59 Overall Conclusion 12
13 10 CFR 50.59 Assessment
- FW Design & Licensing Basis
- USAR described FWCS & Control Valve Design Functions:
- Provide SG Program Level Control during normal operation
- Prevent control and protection interaction with Median Signal Select (MSS) for NR SG level
- Licensing
- Steam Flow/FW Flow mismatch trip elimination
- USAR described Failures and Accident Analysis 13
14
- AMSAC/DSS Design & Licensing Basis
- Design Function: Satisfy 10 CFR 50.62
- AMSAC Actuation: Turbine Trip and AFW actuation
- DSS Actuation: Remove power to the control rods
- Licensing
- Installed WDPF AMSAC to meet requirements of 10 CFR 50.62
- USAR described Failures and Accident Analysis 14 10 CFR 50.59 Assessment
15 10 CFR 50.59 Assessment
- Assessment Approach
- Use current regulatory requirements & guidance
- NEI 01-01 (including Appendix A) endorsed by NRC RIS 2002-22
- NRC IN 2010-10
- Monitoring ongoing NEI/NRC efforts
- 10 CFR 50.59 screening considerations (NEI 01-01 Section 4.3):
- Software considerations
- Functional segmentation
- Time response
- Human System Interface
- Safety to Non-Safety Interface
- NEI 01-01 drives conservative conclusion to screen in 15
16 10 CFR 50.59 Assessment
- Assessment Approach (contd)
- 10 CFR 50.59 Evaluation Considerations (NEI 01-01 Section 4.4)
- Same as screening considerations
- Qualitative Assessment is key to addressing Criterion 1, 2, 5, and 6 of 10 CFR 50.59 16
17 10 CFR 50.59 Assessment
- Assessment Approach (contd)
- NEI 01-01, Section 5.3.1, Factors that Affect Dependability
- The ability to provide reasonable assurance that an upgrade will exhibit sufficient dependability is a key element of 10 CFR 50.59 evaluations
- Qualitative Assessment characteristics:
- System design features
- System design development and quality processes
- Operating history 17
18 10 CFR 50.59 Assessment
- Qualitative Assessment - Design Features
- Design Features to support low likelihood of failure (examples):
- Isolation Devices
- Redundancy
- Architectural assignments
- Segmentation
- Self Diagnostics
- Failure states
- Existing Manual Controls
- Susceptibility Analysis
- Hardware Failures
- Environmental
- Design Defects
- Operator or Maintenance Errors 18
19 10 CFR 50.59 Assessment
- Qualitative Assessment - Design Development and Quality Processes
- Design specification provides requirements for design, fabrication, documentation, testing, and delivery
- Specification and Westinghouse design development processes based upon industry standards
- Specification requires multi-layer testing approach through fabrication, installation, and commissioning 19
20 10 CFR 50.59 Assessment
- Qualitative Assessment - Operating History
- Ovation Experience
- More than 100 Ovation nuclear systems deployed
- Variety of nuclear applications worldwide
- Greater than 500 Rx years of OE
- Fisher DVC Experience
- Over 700,000 sold
- Over 7 years
- OE Research 20
21 10 CFR 50.59 Assessment
- Qualitative Assessment Preliminary Conclusions
- Will demonstrate dependability and low likelihood of failure:
- Required design features maintained and no new failure results
- Design development and quality processes being applied
- Operating history is strong 21
22 10 CFR 50.59 Assessment
- 10 CFR 50.59 Criteria
- Expected 10 CFR 50.59 Criteria 1, 2, 5, and 6 conclusions based on preliminary Qualitative Assessment and preliminary design work:
- No more than a minimal increase in frequency of an accident
- No more than a minimal increase in likelihood of malfunction
- No possibility of an accident of a different type
- No possibility of a malfunction with a different result 22
23 10 CFR 50.59 Assessment
- 10 CFR 50.59 Criteria (contd)
- Other 10 CFR 50.59 Criteria:
- Criteria 3 & 4:
- Systems do not initiate new failures or malfunctions
- Radiological consequences are not evaluated for these events
- Criterion 7:
- Systems do not impact any critical inputs credited in the Safety Analysis for fission product barriers
- Change will not exceed or alter a fission product barrier design basis limit
- Criterion 8:
- Change does not constitute, involve or modify a method of evaluation described in the USAR 23
24 10 CFR 50.59 Assessment
- Preliminary 10 CFR 50.59 Overall Conclusion
- Screens in for evaluation
- Would not require prior NRC approval
- Perform change under 10 CFR 50.59 24
25 Future Actions
- Xcel Next Steps
- Proceed with detailed design
- 10 CFR 50.59 evaluation sufficiently complete in 3rd Quarter 2018
- Opportunity for additional learning with new guidance
- Timing to accommodate project installation
- Unit 2 - 2019
- Unit 1 - 2020 25
26 Summary
- Described the project scope, design, and licensing basis supporting the digital FW and AMSAC/DSS control system change
- Discussed the preliminary 10 CFR 50.59 assessment and conclusions
- Outlined next steps and possible future interaction with the NRC staff 26
27 Feedback and Questions 27
?
28 Acronyms
- BFRV - Bypass Feedwater Regulating Valve
- CCF - Common Cause Failure
- CFR - Code of Federal Regulations
- CR - Control Room
- DCS - Distributed Control System
- DVC - Digital Valve Controller
29 Acronyms
- HSI - Human System Interface
- IN - Information Notice
- I/O - Input/Output
- I/P - Current to Pressure Converter
- LVDT - Linear Variable Differential Transformer
- M/A - Manual/Automatic Control Station
- M/L - Manual Loading Station
- M/P - Motor to Pressure Converter
- MSS - Median Signal Select
- NEI - Nuclear Energy Institute 29
30 Acronyms
- NR - Narrow Range
- NRC - Nuclear Regulatory Commission
- NRR - Nuclear Reactor Regulation (Office of)
- OE - Operating Experience
- OEM - Original Equipment Manufacturer
- P/I - Pressure to Current Converter
- RCP - Reactor Coolant Pump
- RG - Regulatory Guide
- RIS - Regulatory Issue Summary
- Rx - Reactor
- SF/FF - Steam Flow/Feedwater Flow 30
31 Acronyms
- SGWLC - Steam Generator Water Level Control
- SLIM - Small Loop Interface Module
- SME - Subject Matter Expert
- SPV - Single Point Vulnerability
- SWIL - Software In Loop
- USAR - Updated Safety Analysis Report
- WDPF - Westinghouse Distributed Processing Family
- WR - Wide Range 31