Decommissioning Uzbekistan's First Research Reactor

Today, it is standard practice to incorporate a decommissioning plan into the initial setup of a research reactor, but that was not the case in the 1970s when the IIN-3M reactor and many others were built.

“There was a general perception during the early years of building research reactors that decommissioning could be easily accomplished with minimal resources and planning. However, this is clearly not the case,” said Kungurov. “As a consequence, we did not have a plan for the decommissioning process and no information on how to remove or deinstall the equipment, which is where the IAEA’s support was vital.”

IAEA staff and other international experts travelled to Uzbekistan in August 2012 to evaluate the site of the reactor. The goal of the visit was for experts to assess the state of the facility and gather the necessary information to assist Uzbek officials in preparing for decommissioning.

Based on the results of the 2012 visit and other meetings, IAEA experts worked with the national team to develop a decommissioning plan — including a project schedule and cost estimates — in accordance with the IAEA’s recommendations and guidance on decommissioning planning.

“Estimating the costs for decommissioning was one of the most difficult parts of the planning process because our reactor operators had never done it before and it requires a lot of documentation,” said Kungurov. All the information on decommissioning the IIN-3M reactor, such as the specifics of the procedures, equipment and tools to be used, was submitted to Uzbekistan’s national regulatory body for approval prior to beginning work on the ground.

An important step before the decommissioning process can begin is the removal of all fuel and radioactive sources from the premises, as outlined in the IAEA’s safety standards. This typically requires specialized equipment and highly trained experts.

For the IIN-3M reactor, experts worked with the IAEA in cooperation with Russia and the United States to extract and ship the reactor’s fuel back to its country of origin: Russia. A particular challenge in this case was the form of the spent fuel — liquid high enriched uranium — as this was the first time such fuel had been returned to its country of origin by air. This cooperation also included preparing and transporting various disused liquid radioactive sources from the site to a disposal facility.

The decontaminating, dismantling and demolishing process could then begin. The decommissioning process involved taking apart the equipment piece by piece, such as the reactor vessel; eliminating surface contamination and ensuring safe radiation levels; and removing layers of concrete that were used in the reactor box. The IAEA supported each step of the process.

Once the decommissioning process was complete, the IAEA supported a survey of the site, upon request by the Government of Uzbekistan, to check for safe levels of radioactivity. Results showed that the decommissioning was successful as no significant residual radioactivity was found. This independent measurement was in line with the Government of Uzbekistan’s evaluation of the site, and together these findings confirmed it was safe to use for another purpose.

This article was also featured in the IAEA Bulletin on Research Reactors published in November 2019.