Culham study group report on fusion reactors and the environment

The Study Group concentrated its work on the D-T reactor, the most likely first generation system and arguably the 'worst case' model. The only specifically nuclear hazard to persons outside a fusion power station, arises from the release of tritium to the environment. Excluding accidents, and subject to certain assumptions on reactor design, such releases will mainly affect populations near the power station and should be controllable within authorised levels. Other hazards exist which will affect the operating staff but not the general public. These arise from neutron activiation of the structure and tritium absorption in materials and contamination of waste. These hazards will be controlled by high standards of design and operation. It appears that the probability of a serious accidental release of tritium and the area of country affected depend strongly upon the hazard of a lithium fire. The full extent of the hazard and the cost of reducing the probability of the accident to an acceptable level cannot be estimated yet due to the lack of reactor designs. The Study Group has established in outline the major determinants of fusion reactor safety. To establish whether and how the requirements can be met is not possible without more information. Advanced techniques relevant to the principal problems of fusion safety - gas containment and fires in liquid metal systems - have already been developed in the development of fission reactors. Continuing re-appraisals of fusion reactor safety must be an integral part of fusion design. The recommendations of the Study Group emphasise this, and the necessity for basic physical data to aid both design and safety assessments. (author)