Selection and evaluation of decontamination and dismantling techniques for decommissioning of large NPPs components

Highlights: •We analysed main aspects and schemes of the D&D techniques selection. •We present D&D techniques evaluation process and example results. •"Tool-box" techniques allows effectively solve unforeseeable dismantling situations. •Analysis shows that the selection process for D&D techniques is a multi-step process. •"Tool-box" techniques allow flexibility during D&D work planning and implementation. -- Abstract: Most nuclear power reactors were built for one purpose – to produce electricity as safely and economically as possible. Plants were not designed for easy decommissioning. Since decommissioning was not taken into account from the beginning, dismantling and decontamination activities must be planned individually for each unique facility. Fortunately, the process is becoming more predictable and manageable due to gained experiences. Dismantling is the most visual phase of the decommissioning process. All nuclear facilities are unique, so that no single method of dismantling can be all-encompassing. The paper presents main aspects and schemes of the selection and evaluation process used in Lithuania for decommissioning of the emergency core cooling system and auxiliary reactor systems at Ignalina nuclear power plant. In addition, results of a GRS study on the different factors leading to the selection of dismantling techniques for decommissioning of a reactor pressure vessel in Germany are presented.