Analysis of alternatives for radwaste management during dismantling of the equipment in building V1 at Ignalina NPP

Abstract

Ignalina NPP was operating two RBMK-1500 reactors. Unit 1 was closed at the end of 2004, and Unit 2 was closed at the end of 2009. Now preparation for dismantling activities, including building V1, is ongoing. Building V1 is located on the west side of Unit 1. It is a nine-level building with more than 200 rooms. Part of Unit 1 auxiliary systems are located in Building V1. Most systems in this building are contaminated. After situation analysis in Building V1 at Ignalina NPP and collection of the primary information related to the components’ physical and radiological characteristics, location and other data, two alternatives for radwaste management during dismantling were formulated and evaluated: the first, when the decontamination of dismantled components is performed (where it is reasonable) and the second one, when no decontamination of dismantled components is performed and after dismantling the components are routed to appropriate waste storage or disposal sites. To select the preferable alternative, MCDA method – AHP (Analytic Hierarchy Process) was applied. Hierarchical list of decision criteria, necessary for assessment of alternatives performance, were formulated. Quantitative decision criteria for these alternatives were analyzed using software DECRAD, which was developed at Lithuanian Energy Institute Nuclear engineering laboratory. Qualitative decision criteria were evaluated using expert judgment. The results have shown that the first alternative (decontamination is performed) is better than the second one (no decontamination is performed).