Tammiku radioactive waste repository was a former radioactive waste repository located in the village of Männiku in the municipality of Saku.
On the construction of the Tammiku radioactive waste repository
The Tammiku radioactive waste repository was established in the early 1960s as a burial site for radioactive waste from industrial plants, scientific and medical institutions and elsewhere on the territory of the then Estonian SSR.
The burial ground was in use from 1963-1995, until it was taken over by AS ALARA from the previous operator, the then Tallinn Private Car Company.
Facilities of the Tammiku radioactive waste storage facility
The burial site, located in a sandy pine forest near Tallinn, consisted of an underground liquid waste tank with a capacity of 400 m³, with a reinforced concrete and stainless metal inner lining, and an above-ground storage facility for solid waste. The latter consisted of an 18 m long and 8 m wide structure with reinforced concrete walls embedded in sandy soil.
The repository was divided into nine sections, six of which were filled with waste. The top of the sections were covered with concrete panels. To store the waste in the repository, the panels were removed from the top of one of the compartments and a portable metal roof structure with a door was placed on top. When the compartment was full, the roof structure was removed and placed over the next empty compartment. The panels were placed back on the filled section and covered with a layer of waterproofing.
Safety assessment of the Tammiku waste facility
A safety assessment of the Tammiku waste repository carried out in 1994 by the Swedish Institute for Radiation Protection showed that the repository fell far short of the safety requirements for modern radioactive waste repositories. In the same year, a The theft of radioactive substances from the dam an incident in which 1 person lost his life and several others suffered radiation injuries.
As a result of the safety assessment, the landfill has been closed for waste storage since 1995. All radioactive waste generated in Estonia is disposed of in an interim storage facility at the former nuclear site in Paldiski.
The Tammiku waste repository could also not be considered as a disposal facility for radioactive waste because the safety assessment did not ensure the long-term safety of the waste stored there for the surrounding environment and human health. It was therefore decided to decommission the repository by removing the waste that had been stored there for decades, and to transport and store it in an interim storage facility at the former Paldiski nuclear site, which complies with international requirements. Since then, post-decommissioning monitoring has been carried out and the plan is to open the repository for unrestricted use in 2025-2026.
Elimination works at the Tammiku landfill site
The decommissioning of the repository has now been underway for over twenty years. In 2001, the liquid waste tank was completed. Analysis of the liquid waste contained in the tank showed that, given the very low activity of the waste, it was possible and safe to discharge it into the normal sewerage system.
In 2008, following the approval of the EIA report and the issuing of the radiological permit, the removal of solid waste from the repository started. Initially, two metal boxes containing sealed radioactive sources were removed from the repository, representing a small fraction of the total volume of waste, but about 90% of the total activity of the repository.
Between 2009 and 2011, all the remaining waste was removed from the repository and transported to the Paldiski radioactive waste management centre for further treatment. The radiological characterisation, decontamination and dismantling of the repository started in 2012, and by 2025/2026 the repository site and the surrounding territory will become an unrestricted green area.