Further international guidance is needed on effective implementation of the radiation protection principles of justification and optimization in existing exposure situations.

This could include methodologies for assistance in the selection of case specific remediation action levels defined in terms of residual doses or derived quantities as well as procedures for a periodic review of action levels adopted in the early post-accident period to take account of changing radiological conditions. It could also include guidance on appropriate decontamination and remediation techniques. The guidance needs to address technical and scientific issues in addition to socially relevant factors and could promote the development of a coherent, transparent and collectively accepted decision making process.