Nuclear accident consequence assessment in Hong Kong using JRODOS

Area of Science:

• Environmental Science
• Nuclear Safety
• Computational Modeling

Background:

• Off-site emergency management for radioactive releases requires robust decision support systems.
• The Hong Kong Observatory utilizes the Java-based Real-time Online DecisiOn Support (JRODOS) system for accident consequence assessment and preparedness.
• Operational efficiency necessitates the use of computationally efficient dispersion models within JRODOS.

Purpose of the Study:

• To document the application and verification of the JRODOS system, specifically its ATSTEP dispersion model, for emergency management.
• To evaluate JRODOS's capability in short-range simulation through a case study of the Fukushima nuclear power plant accident.
• To assess potential accident consequences at a nearby nuclear power station and compare projected doses with international safety criteria.

Main Methods:

• Adopted the ATSTEP dispersion model within JRODOS for computational efficiency.
• Conducted verification studies by comparing JRODOS simulation outputs with tracer experiment results.
• Performed a case study using the Fukushima nuclear power plant accident data and simulated a hypothetical accident at the Guangdong Nuclear Power Station.

Main Results:

• JRODOS ATSTEP model outputs were generally of the same order of magnitude as tracer data up to 50 km under neutral atmospheric conditions.
• JRODOS simulations for the Fukushima accident produced realistic Cs-137 ground deposition results comparable to actual monitoring data.
• Simulations for a Daya Bay accident indicated projected effective doses within Hong Kong remain below IAEA criteria for urgent protective actions, though thyroid doses may approach criteria in some areas.

Conclusions:

• The JRODOS system, particularly the ATSTEP model, is a capable tool for nuclear accident consequence assessment and emergency preparedness.
• Verification studies and case studies demonstrate JRODOS's reliability in simulating radioactive dispersion and informing protective action decisions.
• JRODOS simulations provide valuable insights into potential radiological impacts, supporting regulatory compliance and public safety in areas surrounding nuclear facilities.