Concepts and methods on clearance of buildings of nuclear facilities. Final report

The problems occurring during the clearance of buildings of nuclear facilities normally arise by the huge amount of material which has to be assessed and by the measuring strategies necessary for these release measurements which differ significantly from these strategies used in operating facilities. Therefore, besides the measuring procedures used in the past, the collimated and uncollimated in-situ-gamma-spectrometry is described in part II of this report. The clearance criteria for buildings are discussed in part I. The aim was not to generate new clearance levels, but to combine the existing clearance levels with the generic averaging quantities and the standardised measuring techniques. To reach this aim, the experiences gained during several measuring campaigns performed in five nuclear facilities are considered (part III). This work leads to recommendations summarized in part IV for the evaluation of release procedures which take into account aspects like the basic radiological safety standards, the purposes of the different measuring techniques and effort. (orig.)