Radiological Impact of Co-Location of the VLLW and LILW Repository at Mochovce Site

Abstract

JAVYS, the Slovak Nuclear Decommissioning Company, the owner and operator of National Radioactive Waste Repository (NRR) at Mochovce, is planning the enlargement of the existing NRR. The enlargement consists of the construction of new structures (double rows) like the ones existing for Low and Intermediate Level Waste (LILW) and of a new facility for the disposal of Very Low Level Waste (VLLW). A VLLW disposal site is being planned in Mochovce where a LILW disposal site is already located. As a part of ongoing licensing process for this change in utilization of the NRR we have updated the already existing assessment of potential radiological impact to members of the public after closure of the site, both from the migration of leachate in groundwater from the site and from possible inadvertent intrusion into the site, including future residential development on material excavated for the construction of a road. The radionuclides from the groundwater reach the biosphere through a stream flowing into the lake. It is conservatively assumed that individual in the critical group uses biosphere of the lake (for irrigations, fishing and recreation). In the case of unintentional intrusion into the repository, the exposed group consists of a small number of workers who excavate or examine repository materials. The assessment is based on preliminary conceptual design for VLLW module, estimation of future volumes for the different waste classes and their radiological inventories and considers some common aspects and potential interactions between both disposal systems, such as radiological criteria, critical group definition, institutional period, site environment, total activity inventory.