This Safety Guide provides recommendations on how to meet the requirements related to safety assessment in the Safety Requirements publication, Safety Standards Series No. WS-R-1, Near Surface Disposal of Radioactive Waste. It addresses the subject of safety assessment for near surface disposal of radioactive waste and provides guidance on approaches to performing safety assessments in the context of near surface repositories.

The ISAM project involved the review and enhancement of post-closure safety assessment methodologies and tools for both existing and proposed near surface radioactive waste disposal facilities. The main objectives of the project were to: (a) provide a critical evaluation of the approaches and tools used in the post-closure safety assessment of proposed and existing near surface radioactive waste disposal facilities; (b) enhance the approaches and tools used; (c) build confidence in the approaches and tools used. In order to help achieve these objectives, the ISAM project paid particular attention to discussing, agreeing and setting down a safety assessment methodology. The ISAM project primarily focused on developing a consensus on the methodological aspects of safety assessment, but also gave considerable attention to illustrating the application of the methodology to three main types of disposal facilities (vault, RADON and borehole type disposal facilities).--Publisher description.

This Safety Guide provides recommendations on how to meet safety requirements on the disposal of radioactive waste. It is concerned with the disposal of solid radioactive waste by emplacement in designated facilities at or near the land surface. The Safety Guide provides guidance on the development, operation and closure of, and on the regulatory control of, near surface disposal facilities, which are suitable for the disposal of very low level waste and low level waste. The Safety Guide provides guidance on a range of disposal methods, including the emplacement of solid radioactive waste in earthen trenches, in above ground engineered structures, in engineered structures just below the ground surface and in rock caverns, silos and tunnels excavated at depths of up to a few tens of metres underground. It is intended for use primarily by those involved with policy development for, with the regulatory control of, and with the development and operation of near surface disposal facilities.

This two-volume publication summarises the methodology for the long-term safety assessment of near surface radioactive waste disposal facilities, developed in the 'Improvement of Safety Assessment Methodologies' (ISAM) co-ordinated research project, as well as giving details of the application of the methodology to three hypothetical test cases.