Safety assessments undertaken using the BIOMASS methodology: lessons learnt and methodological enhancements

Area of Science:

• Environmental Science
• Nuclear Engineering
• Risk Assessment

Background:

• The International Atomic Energy Agency (IAEA) coordinated a project to enhance methods for biosphere modelling in radioactive waste disposal safety assessments.
• The project built upon the earlier IAEA biosphere modelling and assessment (BIOMASS) project, incorporating lessons learned and scientific developments.

Purpose of the Study:

• To refine and enhance the BIOMASS methodology for improved post-closure safety assessments of solid radioactive waste disposal.
• To provide researchers in radioecology and radioactive waste disposal with a summarized review of the enhanced methodology.

Main Methods:

• Reviewed and identified areas of the original BIOMASS methodology requiring enhancement.
• Discussed lessons learned from applying the BIOMASS method.
• Assessed the methodology's usefulness using real-world examples and incorporated scientific advancements.

Main Results:

• The original BIOMASS methodology's overall approach was confirmed as sound.
• The enhanced version clarifies the necessity of an iterative and holistic approach, prioritizing system understanding.
• Experience highlighted the critical role of system understanding in site-specific safety assessments.

Conclusions:

• The enhanced BIOMASS methodology emphasizes an iterative, holistic approach with system understanding at its core.
• Adequate system understanding is crucial for underpinning safety assessments in radioactive waste disposal.
• The integral role of the biosphere in safety assessment is further emphasized in the refined methodology.