[en] The general requirements for applications for license termination and decommissioning nuclear power, research, and test reactors are contained in 10 CFR Part 50, ''Domestic Licensing of Production and Utilization Facilities.'' On June 27, 1988, the Commission published amendments to 10 CFR Part 50 (53 FR 24018) concerning specific criteria for decommissioning nuclear facilities. Amended 10 CFR 50.33(k), 50.75, and 50.82(b) require operating license applicants and existing licensees to submit information on how reasonable assurance will be provided that funds are available to decommission the facility. Amended section 50.75 establishes requirements for indicating how this assurance will be provided, namely the amount of funds that must provided, including updates, and the methods to be used for assuring funds. This regulatory guide has been developed in conjunction with the rule amendments and was published for public comment in May 1989. This version incorporates, where appropriate, the public comments received. Its purpose is to provide guidance to applicants and licensees of nuclear power, research, and test reactors concerning methods acceptable to the NRC staff for complying with requirements in the amended rule regarding the amount of funds for decommissioning. It also provides guidance on the content and form of the financial assurance mechanisms indicated in the rule amendments. 9 refs