risk-informed design for uk abwr project · pdf filebsl bso 2. scope of uk abwr ......
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Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
IAEA International Conference on Topical Issues in Nuclear Installation Safety: Safety
Demonstration of Advanced Water Cooled Nuclear Power Plants Vienna, Austria, 6–9 June 2017
RISK-INFORMED DESIGN FOR UK ABWR PROJECT
Yuki Ishiwatari (Hitachi-GE Nuclear Energy, Ltd.)
Kohei Hisamochi (Hitachi-GE Nuclear Energy, Ltd.)
Naoki Hirokawa (Hitachi-GE Nuclear Energy, Ltd.)
Dennis Henneke (GE Hitachi Nuclear Energy)
AE-OG-5927 Rev.0
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
Contents
1
1. Introduction
2. Scope of UK ABWR PSA in GDA
3. Peer Review
4. Risk-informed Improvements
5. Use of PSA to Support Design Optioneering
6. Summary
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
1. Introduction
22
PO
WER
10,000
15,000
(MWe)
1970 1975 19850
5,000
1995 2005
460460
540
784
1100
840
1100
1100
1100
820
1100
540
1137
1100
1356
1356
20,000
825
1380
1358
Advanced BWR phaseImprovement and Standardization phase
Domestic Production Phase
KASHIWAZAKI-KARIWA 7*
KASHIWAZAKI-KARIWA 6*
KASHIWAZAKI-KARIWA 4
HAMAOKA - 4*SHIKA - 1
KASHIWAZAKI-KARIWA - 5
SHIMANE - 2
HAMAOKA - 3*
FUKUSHIMA II - 4
FUKUSHIMA II - 2
HAMAOKA - 2*
TOKAI - 2*
FUKUSHIMA I-4HAMAOKA - 1*
SHIMANE – 1
(First Made-in-Japan NPP by Hitachi)
ONAGAWA - 3*
HAMAOKA - 5*
SHIKA - 2
1358SHIMANE - 3
2010
1373
OHMA – 1*1380
TSURUGA-1*
FUKUSHIMA I -1*
HD – 1*
NK – 1
1385
1373
MWe
357
Under constructionUnder construction
Under planning• 40 years continuous
construction and
maintenance
• 20 of 54 NPPs in
Japan by Hitachi-GE
(incl. cooperation
construction*)
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
1. Introduction
3
www.hitachi-hgne-uk-abwr.co.uk/downloads/2016-05_abwr-brochure.pdf
http://www.onr.org.uk/saps/saps2014.pdf
Hitachi-GE proposing to build ABWR plants in UK, based on experience of ABWRs in Japan and their design enhancements (i.e., Fukushima lessons)
Under Step 4 of Generic Design Assessment (GDA) and Generic Environment Permit (GEP)
UK regulatory expectation: Demonstrate ALARP(As Low As Reasonably Practicable)
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
1. Introduction
4
Hitachi-GE’s ALARP methodology
PSA has been used to support ALARP assessments
www.hitachi-hgne-uk-
abwr.co.uk/downloads/2015-10-30/UKABWR-
GA91-9101-0101-28000-RevB-PB.pdf
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
2. Scope of UK ABWR PSA in GDA
5
Numerical Tragers:
-
-
-(BSL)
(BSO)
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04
全予測頻度
(/年)
敷地外線量当量 (mSv)
BSL
BSO
2. Scope of UK ABWR PSA in GDA
6
Risk Targets:
- Offsite dose band frequencies
- Individual risk offsite
BSL: 1E-4/y, BSO: 1E-6/y
- Total risk of 100 or more fatalities
BSL: 1E-5/y, BSO: 1E-7/y
Intermediate measures for risk-informed improvements:
- Core Damage Frequency (CDF)
- Fuel Damage Frequency (FDF)
- Large Release Frequency (LRF)
- Large Early Release Frequency (LERF)
http://www.onr.org.uk/saps/saps2014.pdf
Dose [mSv]
Fre
q.
[/year]
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
2. Scope of UK ABWR PSA in GDA
7
SourceInternal events
Internalfire*
Internal flood*
Seismic*OtherIHs*
Other EHs*
Reactor(at Power) Detail assessment
Bounding assessment
Reactor(Shutdown)
Scoping Analysis
SFP
Fuel Route
Qualitative discussions to argue risk is insignificant
Turbinesystem
Simplified approach
(insignificantrisk)
Radwastesystem
* Retained after screening process in IAEA SSG-3
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
2. Scope of UK ABWR PSA in GDA
8
UK ABWR PSA was developed along with generic design development. Engineering teams in Hitachi-GE (as a plant vender) supported development/use of PSA.
PSA Support Team in Hitachi-GE
Systems
Design sections(Civil, Layout, Equipment)
C&I Electrical Fire assessment
Flooding assessment
Fragility analysis
Provide PSA input (design)- Design Information- FMEA- Capacity
Containment Performance
O&M
Design section(Civil, Layout, Equipment)
Provide PSA input (analysis)- Hazard- Fragility- Deterministic assessment
PSA Core Team
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
3. Peer Review
9
- Organized by GE-Hitachi
- Reviewed by industry experts from US and UK
- Similar process as performed in US (i.e., NEI 05-04)
- Covers Level 1~3 PSAs for all of the detailed/bounding assessments, as well as hazard screening process
- Reviewed against:
✓ UK Technical Assessment Guides
✓ ASME/ANS PRA Standards (including trial use or draft versions with provided feedback to ASME/ANS)
- Includes documentation of any peer review comments, as well as resulting responses
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
4. Risk-informed Improvements
10
ABWR Evolution through PSABWR
ABWR
ABWRs in Japan
UK ABWR (GDA)
- ECCS Configuration- ATWS countermeasure, etc.
- Alternate Water Injection/Spray- Hardened Containment Venting etc.
- LDF, COPS- Auto SLC, CTG, etc.
- Risk-Informed Design through Design changes and PSA development
- Examination on further design enhancementPSA developed
UK ABWR (Site Specific)
US ABWR
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
4. Risk-informed Improvements
11
During development of UK ABWR PSA
- PSA developed along with generic design development
- Design assumptions developed and recorded where necessary
- Design improvements / specific design options recommended from preliminary PSA results
- These recommendations implemented into PSA and recorded as design assumptions (where agreed with designer)
- Examples in next slide
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
4. Risk-informed Improvements
1212
During development of UK ABWR PSA
Incorporated in generic design
e.g., Backup room cooling system,Countermeasure against digital C&I CCF
e.g., Use of non-Class 1,2 systems as alternative injection measures
Options raised based on
preliminary PSA results
Basic requirements and high level design
Assumptions recorded and tracked
4. Risk-informed Improvements
e.g., Resonance frequency (seismic)Cable routing (fire)Component critical height (flood)
Way of dispassion depends on project schedule.
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
4. Risk-informed Improvements4. Risk-informed Improvements
13 Hitachi-GE Nuclear Energy, Ltd. Proprietary InformationHGNE COMMERCIAL
HGNE COMMERCIAL
5
Initial Identification of Options➢ Review of PSA results (MCS, Importance, low order
cutset, etc.)➢ Review of sensitivity analyses➢ Review of assumptions and uncertainties
Review with Engineering team➢ Generation of “Use of PSA” sheet➢ Review for additional options
Listing of options➢ Risk insights, design features and identified options
are put in the first table
Risk insightsIncorporated designOptions
Examination of further risk reduction➢ If the above criteria are met, the baseline option
should be selected over the alternate option.➢ If not, further assessment including identification of
implementation phase is considered.
Justification of BaselineAdditional assessmentImplementation Phase
FirstStep
Second Step
After development of
UK ABWR PSA
1. Identification of options
• Review of PSA results
• Review of sensitivity analysis
• Review of assumptions / uncertainties
• Review by designers
2. Examination of options
• Grossly disproportionate?
• Reasonably practical?
• Phase of implementation?
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information
4. Risk-informed Improvements4. Risk-informed Improvements
14
After development of UK ABWR PSA
Example of options implemented / to be implemented
• Set performance objective of nitrogen leak rate from a Safety Relief Valves for long term operability
• Increase thickness of specific pipe segment to further reduce risk from ISLOCA
• Introduce measures to avoid initiating events caused by a human error (e.g., using interlocks)
• Apply fire rating to specific intra-divisional boundaries
• Improve seismic fragilities of specific components (as reasonably practicable) which were found to drive seismic risk
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information 15
5. Use of PSA to Support Design Optioneering
PSA has been used to provide risk impacts from proposed design changes or justify baseline design
Examples:
• Category and Class
• Component location
• Surveillance interval
• Reactor depressurisation system design
• Severe accident countermeasures
Hitachi-GE Nuclear Energy, Ltd. Proprietary Information 16
6. Summary
• UK ABWR under GDA
• UK regulatory expectation: Demonstrate ALARP
• PSA as part of generic design process to support ALARP demonstration
• Full-scope PSA to compare with risk targets
• Use of peer reviews
• Risk-informed improvements during PSA development
• Systematic identification and examination of ALARP options based on developed PSA
• PSA also used to support design change decisions