Experimental determination of a decommissioned nuclear reactor

The radioactive inventory was determined by sampling and laboratory analysis for the activated components such as the reactor internals, the pressure vessel and the neutron shied tank etc at a decommissioned nuclear reactor (PWR). The most important radionuclides and their activation reactions considered were showed. The techniques and instruments utilized in laboratory analysis were provided. Lastly, radionuclide residues for the main activated components were estimated. It was shown that radionuclide residues were mainly hold in the reactor internals, which represents 94%, and the pressure vessel 6%, the quantity of residues in primary shields was little. (authors)