The decommissioning of uranium-graphite reactor EI-2 at Russia's Siberian Chemical Combine (SCC) was formally accepted as completed by a government commission at a ceremony on 25 September. It is the first ever decommissioning of a commercial uranium-graphite reactor.
To guarantee safe storage of the reactor for tens of thousands of years, SCC in 2010 established joint stock company Experimental Demonstration Centre Decommissioning Uranium-Graphite Reactors (JSC UDC PEM). In co-operation with leading research centres of the Russian Academy of Sciences, JSC UDC PEM developed a unique decommissioning technology in which all reactor cavities are filled with a mix of natural clays.
"The reactor is filled with clay under pressure to eliminate all empty spaces inside. We also piled clay on top of EI-2 to form a hill, which is then covered with inert materials - sand and crushed stone, Andrei Izmestiev from JSC UDC PEM explained. "No concrete is used." The project was finished two months ahead of the schedule and work is now underway to construct a protective shield against weather impact. SCC CEO Sergei Tochilin told a press conference in Seversk that completion of the project will improve public confidence in the nuclear industry.
EI-2 began operating in February 1958 at the Tomsk-7 closed city (now Seversk) in the Tomsk region. It was SCC's second industrial uranium-graphite reactor. The first (I-1) was launched in 1955 and together they formed the first dual-purpose NPP producing both weapons-grade plutonium and 100MWe of electricity. In the 1960s SCC put three more dual purpose reactors into operation (ADE-3, ADE-4 and ADE-5) boosting power production to 600MWe.
Under a Russian-US agreement to end production of military-grade plutonium I-1, EI-2 and ADE-3 were shut down in the early 1990s and the other two reactors were stopped in 2008.
The technology developed for the decommissioning of EI-2 will now be applied to Russia's other uranium-graphite production reactors. As well as the five at SCC, there are five at the Mayak Chemical Combine in Ozersk and three at Zheleznogorsk's Mining & Chemical Combine in Krasnoyarsk. Together they produced 170t of weapon-grade plutonium between 1948 and 1994, according to the World Nuclear Association.
Russia's 2011 law on Management of Radioactive Waste characterises as "special" radioactive waste that is too dangerous or expensive to move. The waste produced by military programmes, including the Seversk reactors, and waste resulting from a nuclear accident is automatically characterised as "special".
A project is now underway to develop storage for such waste at Seversk. Izmestiev said the new facility will be safe for tens of thousands of years. Investments in development of the waste storage facility is estimated at RUB2.8bn ($42m), according to Denis Yegorov, Deputy Director of National Operator for Radioactive Waste Management (NO RAO). The total capacity of the facility will be 150,000 cubic metres and construction is planned for 2017-2021. Annual operating expenditures will be RUB100m. The facility will be in operation from 2021 to 2035 with possible extension to 2040. NO RAO has started the environmental impact assessment (EIA) for siting and construction of the facility.
In addition, the International Atomic Energy Agency and the Organization for Economic Cooperation and Development Nuclear Energy Agency are considering setting up an international pilot site at the SCC to develop irradiated graphite management technologies, Izmestiev said. The issue will be discussed at a meeting in Seversk in October.
