6.78. In most States, regulatory guidelines have not yet been issued on when retrieval is necessary and how requirements for retrievability, if any, should be implemented. Where retrievability is mentioned in national regulatory guidelines, there is usually an overriding requirement that any measures to enhance retrievability should not compromise the passive long term safety of a disposal facility. If retrievability is required as part of the national waste management policy, the regulatory requirements for retrievability should be reviewed to check that they are consistent with requirements for maintaining nuclear security and safety - including requirements for radiation protection and measures required under the system of accounting for and control of nuclear material - both in possibly prolonged periods before closure of the facility and in the long term.