Probabilistic Safety Assessment and Human Reliability Analysis (PSA/HRA) Sub-committee

• Sub-committee Aim:
✓ To review the state-of-the-art methods and standards towards PSA and HRA on nuclear reactors;
✓ To provide data-centric solutions towards risk, reliability, and resilience analysis for nuclear safety under uncertainty; and
✓ To provide a platform for regional and international discussions on research developments regarding PSA and HRA on nuclear safety endeavours.

• Sub-committee Focus:
✓ Reviewing the operational needs of existing nuclear reactors in the region as part of a literature survey;
✓ Developing state-of-the-art methodologies towards risk, reliability, and resilience analysis for nuclear safety; and
✓ Comparing results between different codes/methodologies used for such analysis through well-defined benchmark problems.

• Research challenges:
✓ Challenge 1: Availability of sparse/limited component and human reliability data;
✓ Challenge 2: Characterising the uncertainty over the risk, reliability, and the resilience estimates towards risk-informed decision-making; and
✓ Challenge 3: Extracting and integrating meaningful data to develop interpretable and explainable machine-learning method to assess component/human performance.

The 3R Framework:

❖ Theme 1: Learning from data, physics, and contextual knowledge
❑ Focus: Development of supervised machine-learning techniques to predict the reactor system performance
towards performing a reliability analysis, resilience assessment, and system health monitoring – e.g., Physicsinformed
Neural Network, Digital-twin, and Reinforced-learning.

❖ Theme 2: Information extraction and interpretation from data
❑ Focus: Development of unsupervised machine-learning techniques to extract key features and information from
the measurements, social media platforms, noisy monitoring data, and expert opinions – e.g., Principle Component
Analysis, Reduced-order modelling, K-Nearest Neighbours, and Anomaly detection.

❖ Theme 3: Uncertainty quantification & Variability characterization
❑ Focus: Development of inverse methods to quantify the uncertainty and variability of key physical model input
parameters given the limited data, as well as robust computational approaches for forward methods towards
uncertainty propagation – e.g., Markov Chain Monte Carlo, Probability bounds analysis, and Dependency-tracking.

❖ Theme 4: Accident modelling & Emergency response
❑ Focus: Development of state-of-the-art modelling approaches towards characterizing complex accident sequences,
identifying the most significant contributing factor to the accident event, and deriving a risk-informed emergency
response plan – e.g., Dynamic fault-tree analysis, Multi-unit PSA, Bayesian network, and Petro-net models.

Topics of interest includes:
❖ Accident modelling
❖ Machine-learning methods for Uncertainty analysis
❖ Sensitivity analysis
❖ Monte-Carlo methods for parameter identification
❖ Prognostics and system health management
❖ Human factors in system reliability, safety and security
❖ Reliability, safety and security of components and systems
❖ Mathematical/Simulation methods in reliability, safety and security
❖ Reliability, safety and security related management systems
❖ Model verification and validation
❖ Disaster preparedness, mitigation and response

Recent Activities (since 2023):
✓ Attended Joint TINT – Nuclear Malaysia ASEAN NPSR Technical Meeting on PSA and HRA on Nuclear Research Reactor 2023 @ Bangkok, Thailand (18-JUL to 20-JUL)
✓ Attended European Safety and Reliability (ESREL) Conference 2023 @ Southampton, UK (3-SEP to 7-SEP)
✓ Attended ASEAN NPSR Annual Meeting 2023 @ Singapore, Singapore (9-OCT to 11-OCT)
✓ Asian Symposium on Risk Assessment and Management 2023 @ Hong Kong SAR, China (4-DEC to 6-DEC)
✓ Attended European Safety and Reliability (ESREL) Conference 2024 @ Krakow, Poland (16-JUN to 20-JUN)

Upcoming Activities:
✓ Attending Probabilistic Safety Assessment and Management & Asian Symposium on Risk Assessment and Management 2024 @ Sendai, Japan (7-Oct to 11-OCT 2024)
✓ Attending ASEAN NPSR Annual Meeting 2024 @ Singapore, Singapore (TBD, 2024)
✓ Attending Asian Symposium on Risk Assessment and Management 2025 (ASRAM 2025) @ Pattaya, Thailand (27-AUG to 29-AUG 2025)

Publication:
❑ International Journals
✓ Lye, A., Vechgama, W., Sallak, M., Destercke, S., Ferson, S., Xiao, S., (2024) “Advances in the reliability analysis of coherent systems under limited data with confidence boxes”, ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering (Accepted).

Contact Points: 

Malaysia: ❑ Phongsakorn Prak Tom
✓ Research Officer at Malaysian Nuclear Agency
✓ Email: phongsakorn@nm.gov.my
✓ Interests: Nuclear Power Plants, Thermal Engineering, Heat Exchangers, Emission, Engineering Thermodynamics, Safety
✓ ResearchGate: https://www.researchgate.net/profile/Phongsakorn-Tom
✓ Google Scholar: https://scholar.google.com/citations?user=Elw7PogAAAAJ&hl=en

Singapore: ❑ Adolphus Lye
✓ Post-doctoral Research Fellow, Singapore Nuclear Research and Safety Institute, National University of Singapore
✓ Email: snrltsa@nus.edu.sg
✓ Interests: Stochastic model updating, Markov
✓ ResearchGate: https://www.researchgate.net/profile/Adolphus-Lye
✓ Google Scholar: https://scholar.google.co.uk/citations?user=FJrZavIAAAAJ&hl=en

Thailand: ❑ Wasin Vechgama
✓ Nuclear Engineer (Professional Level), Thailand Institute of Nuclear Technology
✓ Email: wasin@tint.or.th
✓ Interests: Nuclear engineering, Human reliability analysis, Bayesian inference, Risk perception, Accident modelling, Sensitivity analysis, Source-term analysis, Cyber-security
✓ ResearchGate: https://www.researchgate.net/profile/Wasin-Vechgama
✓ Google Scholar: https://scholar.google.com/citations?user=hUTYd6gAAAAJ&hl=th