N uclear accidents such as Chernobyl have f a r reaching impacts on ecological systems. Likewise they have major implications for agricultural systems, since crops and livestock can become contaminated and rendered unfit for human consumption. A range of "countermeasures" exists, however, which can mitigate these impacts and allow food products to be saved. The CESER project has been concerned with the development of a system to assess the environmental sideeffects of such countermeasures. Estimates of the economic costs of these environmental side-effects have been made for a number of case study sites in the VK, using environmental models and a n original contingent valuation study. Estimates of f a r m level (private) costs are also included.