Most of our coding work falls into four overlapping categories: producing computer code; writing code documentation; code verification and intercomparison studies. Most of this work has related to atmospheric dispersion or the underground disposal of radioactive waste.

Code production. Examples of codes that we have been involved in writing include: production of a network code for modelling flow and radionuclide transport in fractured rock (including matrix diffusion); development of an assessment code including near field, geosphere and simple biosphere components; developing and coding a mathematical model of the interaction between sea surface waves and internal waves; extending a one dimensional model solute transport to include sorption on colloids; developing and coding a mathematical model of microbial growth and gas production in a landfill site.

Code documentation. We have been involved in producing user, technical and programmer’s guides to BNFL's MONDRIAN network model (used for assessing surface disposal of radioactive waste). As well as documenting codes that we have been involved in producing, we have also contributed to the documentation of UK Nirex computer codes MASCOT and NAPSAC.

Code verification. We have developed and implemented programmes for testing: HMIP's DECOS-MG, a compartment biosphere model which allows multiple glaciations; the near field and far field components of BNFL's MONDRIAN network code; and for ADDOP, a model of atmospheric dispersion and deposition. We have also tested enhancements to TRAFFIC - BNFL's a 3D finite element groundwater flow and transport code including interactive chemistry. We have been involved in the validation of the UK ADMS atmospheric dispersion code, developed by CERC.

Intercomparison studies. As part of the verification of MONDRIAN we reviewed the performance of different models in the IAEA international NSARS exercises. We wrote the Stripa intercomparison reports on the comparison between the model predictions and the observations for the Site Characterisation and Validation experiments.