Safety Evaluation of Interim Storage Containers

Our competence is the safety evaluation of containers for long-term interim storage of highly radioactive wastes such as irradiated spent fuel elements from nuclear power plants or vitrified wastes from reprocessing. BAM performs this safety evaluation based on the German Atomic Energy Act (Atomgesetz, AtG) when commissioned by the Federal Office for Radiation Protection (Bundesamt für Strahlenschutz, BfS) in approval procedures or by the competent regulatory bodies in nuclear supervision procedures.

The full text of the German Atomic Energy Act and other current legal regulations can be found on the BfS website.

Key areas

Safety evaluation

Transport of a CASTOR^® cask at 0.3 m height in a temporary storage facility (source: BLG)

• for the long-term performance of containers and all associated components (e.g. sealing systems) under storage-specific operational conditions (temperature, moisture, radiation intensity, mechanical load)
• securing the safe enclosure of the radioactive inventory under mechanical and thermal loads at proper operational conditions
• the effects of a hypothetical crash of a container while being handled in a nuclear storage facility (design basis accidents)
• the container in case of beyond-design accidents (e.g. crash of a military aircraft)
• modifications or special features of containers during interim storage  

and

• assessment, determination and monitoring of the necessary quality assurance measures for the development, manufacture and operation of containers (material and component specifications; testing, working & installation and operational instructions, e.g. container handling after loading, container storage and monitoring of container leak-tightness during storage)
• the issuance of conformity certificates for each container showing that it complies with all quality requirements for interim storage
• on-site expert monitoring of first time implemented or substantially changed handling steps of interim storage containers (e.g. installation procedures for the lid sealing systems, verification of helium leak-tightness, drying and residual moisture content measurement)

Test methods

• Safety assessment using numerical methods or models (e.g. analytical approximation methods or suitable finite element analysis)
• Performing experimental tests or using their results
• Conducting comparative, transferability or model considerations

Safety science investigations

The Section performs investigations on container safety in order to maintain and develop the necessary specialist competence as well as developing test methods and test standards, in particular on:

• safety relevant influence of mechanical and thermal loads on containers and their components
• long-term behaviour of materials (e.g. polymers for neutron shielding) and structures (e.g. metallic and elastomeric sealing systems)
• determination of container design safety margins.

Consultation and advice

The Section provides advice on all issues concerning safety of interim storage containers for highly radioactive wastes. It provides advice for    

• the public,
• the ministries of Germany and the Federal States (Länder),
• other authorities and
• industry.

Moreover, the working group participates in information exchanges in this specialist field e.g. by organizing semi-annual seminars on quality monitoring of container manufacture and in the management of the “coordinating institution for cask dispatching information” (Koordinierungsstelle für Informationen zur Behälterabfertigung, KOBAF).

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