At the top level a series of sub-models for the near-field, geosphere and biosphere can be implemented in AMBER, and these can be further discretised. Typically the following processes are included in the model:

• container failure;
• leaching from the waste due to infiltration of rainwater;
• water-borne transport through the engineered structure and unsaturated zone;
• advection and dispersion through an aquifer;
• abstraction of irrigation and other water;
• leaching from the soil due to water infiltration;
• erosion from the soil;
• ingestion of drinking water;
• ingestion of soil;
• external irradiation from soil;
• inhalation of suspended atmospheric material;
• ingestion of meat and milk;
• ingestion of crops.

Quintessa employees have delivered a number of training courses on near-surface disposal modelling and wider aspects of safety assessment in support of national radioactive waste safety programmes. As a consequence, AMBER has been used to assess near-surface disposal facilities for low waste in a variety of countries such as Canada, Indonesia, Lithuania and Romania.

Lead image courtesy of ONDRAF/NIRAS.