SwiBAC: Swiss Biosphere Assessment Code

Quintessa provides post-closure radiological modelling support to the National Cooperative for the Disposal of Radioactive Waste (Nagra), the organisation responsible for preparing the technical and scientific basis for the safe, long-term management of radioactive waste in Switzerland.

Quintessa has implemented Nagra's post-closure biosphere assessment model in a new software tool, the Swiss Biosphere Assessment Code (SwiBAC).

SwiBAC takes user input and generates models that are run using AMBER, Quintessa's generic compartment modelling code. SwiBAC runs the calculations and reports key and additionally requested output back to the user. The underlying models and calculations can be fully scrutinised by exploring the AMBER case files.

SwiBAC is run via text input files, the style of which is fully consistent with those for Nagra's source term and geosphere modelling codes, STMAN and PICNIC, which are also maintained and supported by Quintessa. SwiBAC can directly use time-dependent radionuclide fluxes from PICNIC geosphere calculations as input, facilitating integrated calculations. Alternatively calculations can be undertaken on a unit source term basis. SwiBAC tracks radioactive decay chains so that biosphere dose conversion factors can be provided.

The conceptual and mathematical basis for SwiBAC are fully described in supporting documentation, together with the verification of the code. SwiBAC is developed and maintained within Quintessa's TickITplus accredited quality management system.