Sweden was one of the first six countries to build and operate a nuclear power reactor. Thus, there exists a corresponding legacy in terms of liabilities for decommissioning and waste management of the historic facilities. Compliance with the Polluter Pays Principle (PPP) and its corollary on equity between generations implies that plans for decommissioning must be made and funds set aside for its execution. The need for precision in the cost estimates often governs the timing of the technical planning. Cost estimates are treacherous since cost raisers may be identified and evaluated only after considerable efforts have been made. Further complications and challenges arise as a result of changes that take place between construction and decommissioning of facilities in terms of the entities involved as owners, operators, license holders, Authorities and financiers. From this perspective, the present paper summarizes the general legislation as well as the legislation that applies particularly to nuclear activities. It also summarizes the relation between the nuclear decommissioning fund system and financial reporting. Three examples are provided that wholly or partially fall under the Studsvik act (that specifically covers old facilities): The Ågesta nuclear power plant The Ranstad uranium mining and beneficiation facility The Neutron Research Laboratory at Studsvik The findings include the following: It is important that the legislation be clear as to what is included and not. The rationale for the legislation should also be clear and well communicated. Old agreements can be significant for the assessment of liabilities, even in cases where a party may no longer exist. Support for assessment of when activities are continuing or not (which may have a strong significance for the liability) can be found in court cases on chemically contaminated soil. Analysis of facilities and the work carried out at different times can be very helpful in determining whether or not a facility is auxiliary. In order to be essentially correct, annual reporting must be coherent with the declarations of the funding system and in compliance with the IAR/IFRS standards. Keeping of searchable records is essential Research is essential, not only to provide bases for high quality decisions, but also to promote consensus based on agreement on factual circumstances