Where a repository is already in operation, waste generators will usually be anxious to process and despatch their low — and intermediate-level waste as soon as possible — recognising that the business of an NPP is electricity generation not waste management. Where there is no disposal facility in existence, however, (and this is usually the case for deep disposal) there may be considerable uncertainty about how the waste ought to be processed to meet the waste acceptance criteria of the yet-to-be-created facility. In such circumstances the waste producer may prefer a ‘wait and see’ strategy in which the waste is kept in its raw state. This may not be acceptable to the regulator, however, who, understandably, will want to see that the waste is stored in a passive state. Preliminary treatment is one way around this dilemma but has the significant disadvantage that the waste will then need to be processed twice: once for storage and again for disposal. A solution that has been used successfully in many countries is the formulation of ‘preliminary waste acceptance criteria’, basing these upon an outline design for a waste disposal facility that is considered to be both feasible and affordable. Waste acceptance criteria (WAC) are normally established by the body that has ultimate responsibility for radioactive waste disposal: the waste management organisation (see next section).