6101 project. Decommissioning of Maišiagala Radioactive Waste Storage Facility

MAIŠIAGALA RADIOACTIVE WASTE STORAGE FACILITY (MAIŠIAGALA RWSF)

Maišiagala RWSF was constructed in 1963. It is located in Bartkuškis forest of Žalioji forestry, Širvintos district, at the distance of 9 km from Maišiagala to the northeast, and 40 km from Vilnius.

Maišiagala RWSF is a 200 m³ capacity monolithic reinforced concrete basement, located at a depth of 3 metres, into which radioactive waste has been placed and covered with liquid concrete. The concrete absorbs and weakens ionizing radiation emitted by the radionuclides contained in the radioactive waste, and prevents them from being washed out with water and further spreading. Similar storage facilities were built in many places of the former Soviet Union and in Eastern Europe states.

Waste loaded to Maišiagala RWSF are radioactive waste generated by the use of radioactive materials and radioactive sources in industry, medicine and scientific research. Waste was transported to the storage facility located in Bartkuškis forest not only from Lithuania, but also from Kaliningrad and Grodno regions.

The waste at Maišiagala RWSF was collected until 1989. After that, it was decided to decommission this storage facility, because it did not meet the actual environmental protection requirements. There should be noted that the waste was not sorted, i.e. short-lived and long-lived waste was stored together. In accordance with the actual requirements, each type of waste should be stored in separate depositories, in special packages, as well as in specially equipped depositories for radioactive waste. At the time of decommissioning, about 120 m3 of radioactive waste had been accumulated and the repository was filled by 60 percent. The remaining space was filled by sand, and covered by concrete, bitumen, asphalt and a thick layer of soil.

Until 2002, Maišiagala RWSF was supervised by the Institute of Physics. Since 2002, the Radioactive Waste Management Agency (RATA) has been taking care of Maišiagala RWSF, and since 2019 – SE Ignalina Nuclear Power Plant.

MAIŠIAGALA RWSF SAFETY IMPROVEMENT

During the performing of continuous monitoring of Maišiagala RWSF, a small amount of tritium was found in water of wells drilled near the storage facility for observation purposes. It should be noted that the quantity of tritium did not exceed permissible norms. Moreover, such water did not reach even the nearest water bodies or wells of residents. However, this pointed to the need to strengthen the protective barriers of the storage facility established during the Soviet times to prevent the release of radioactive substances into the environment. Therefore, in December 2002, the European Commission allocated the funding and confirmed PHARE project “Maišiagala Radioactive Waste Storage Facility safety assessment and improvement”, the main objective of which is to improve the radiological safety of the storage facility environment. The project was implemented in 2006. The main stage of this project is the installation of new protective barriers for the storage facility. According to the project developed by French specialists, additional protective barriers – a system of soil and two waterproof membranes – were installed above the radioactive waste basement. These barriers protect radioactive waste placed in the storage facility from water. This is very important to ensure that radioactive materials will not be discharged into the environment together with water.

The whole territory of the storage facility was fenced with the special double fence, and cables were laid to detect the movements. Video cameras were also installed to monitor the territory. The mentioned measures ensure the physical safety of the storage facility, i.e. protecting the access of undesirable persons to the storage of radioactive waste.

Maišiagala radioactive waste storage facility after the implementation of PHARE project

The U.S. Department of Energy has made a significant contribution to improving the physical security of Maišiagala RWSF. In 2004, the mentioned department provided the support during the design and installation of the continuous monitoring system for the storage facility.

SUPERVISION AND ENVIRONMENTAL MONITORING OF STORAGE FACILITY

  The environmental monitoring programme for the storage facility was developed and implemented. The purpose of environmental monitoring of the storage facility is to check how the condition of the radioactive waste storage facility is changing and whether it meets the requirements for the storage facilities. Ten wells have been drilled to monitor the storage facility environment, and groundwater samples are systematically taken from these wells. In accordance with the legal acts and regulations of the Republic of Lithuania, as well as the environmental monitoring programme, the timely taking of samples of the storage facility environment is ensured, also the analysis of the samples and evaluation of the results obtained, preparation and distribution of the evaluation report and keeping of evaluation data. If any signs of pollution are detected, the necessary measures shall be immediately applied to identify the causes of pollution and eliminate them.

MAIŠIAGALA RWSF DECOMMISSIONING

There are accumulated comparatively small amounts of radioactive waste – about 120 m3 – at Maišiagala RWSF, but there are different types of waste: short-lived very low level waste, short-lived low level and intermediate level waste and long-lived waste. After the performing of detailed safety assessment of the storage facility, it was defined that the engineering barriers placed on the ground surface cannot provide long term protection against the spread of radionuclides; therefore, the radioactive waste storage facility cannot be reconstructed to a depository. For final disposal, the waste should be sorted, packed into special packages and placed to radioactive waste depositories – each type of waste into a separate depository.

According to the conclusions of experts, Maišiagala RWSF cannot be considered a final waste disposal site. In this regard, the decision was made that Maišiagala RWSF shall be decommissioned and radioactive waste contained in it shall be transferred to the Ignalina NPP for storage and disposal into depositories.

For this purpose, on 15 December 2016, the agreement was concluded with the Environmental Projects Management Agency (APVA) on implementation of the Maišiagala RWSF decommissioning project. The project is financed by the European Union structural funds, the Cohesion Fund. In order to protect the environment from the potential hazards, radioactive waste will be removed from the storage facility and the radiation control of the storage facility territory further will not be performed. It is planned that the waste will be removed and the territory of Maišiagala RWSF will be arranged by the end of 2023. The SE Ignalina Nuclear Power Plant is the executor of the Maišiagala RWSF decommissioning project, and APVA – the implementing institution.

During the project implementation, in 2017-2018, the Environmental Impact Assessment Report on the planned economic activity “Decommissioning of the Maišiagala Radioactive Waste Storage Facility” was prepared and agreed with the interested institutions, and on 5 June 2018 the responsible institution – Environmental Protection Agency – made a decision on the admissibility of the planned economic activity “Decommissioning of the Maišiagala Radioactive Waste Storage Facility” regarding the environmental impact. The decision was made – the planned economic activity “Decommissioning of the Maišiagala Radioactive Waste Storage Facility” is admissible according to the alternative term presented in the Environmental Impact Assessment Report – immediate decommissioning.

Also, in 2017-2018, the Final Plan for Decommissioning of the Maišiagala Radioactive Waste Storage was prepared, which, after agreement of interested institutions, was approved by Order No. 1-272 of the Minister of Energy of the Republic of Lithuania on 5 October 2018. This plan outlines how the process of Maišiagala RWSF decommissioning will be implemented.

In order to carry out decommissioning work on Maišiagala RWSF, it is necessary to obtain a license issued by the State Nuclear Power Safety Inspectorate (VATESI) for nuclear facility decommissioning. Therefore, in 2019-2020 the main attention is paid to preparatory work and preparation of the documents necessary to obtain a license for decommissioning.