Dismantling of MR-Reactor IN-Vessel Setups

Abstract

The results of dismantling performed on the in-vessel structures of the MR research reactor at National Research Center Kurchatov Institute are presented. Remote-controlled mechanisms and remote methods of diagnostics of the radiation conditions were used to perform the operations. These methods and technologies made it possible to provide radiation protection for the staff performing radiation-hazardous work and meet the dose-load requirements established in the regulatory documents. The results of dose-rate measurements in the work zones and the irradiation doses to personnel performing this type of work are presented.The MR research reactor at the National Research Center Kurchatov Institute is being decommissioned. During its period of operation the reactor was equipped with nine loop facilities for conducting a series of tests and investigations of different types of fuel elements, fuel, and structural materials. These facilities made it possible to study the thermophysical, hydrodynamic, and strength characteristics of elements of the core and the primary equipment of power reactor setups intended for different purposes under conditions as close as possible to natural. Its power together with the loop facilities reached 50 MW [1,2].The equipment of the loop facilities was placed in the basement rooms of the MR reactor building and was highly contaminated -the equivalent dose rate in individual rooms reached 20 mSv/h. In 2013-2014, the equipment in all nine loop facilities was disassembled and about 47 rooms were emptied of equipment [3]. The disassembly of the equipment made it possible to reduce the equivalent dose rate in rooms from 5-20 to 0.01-0.03 mSv/h. The in-vessel facilities of MR were disassembled in 2014.Aside from this, high-activity elements of the reactor and beryllium blocks were removed from the cool-down pool. The beryllium blocks, being structural elements of the core, and the graphite blocks, playing the role of the refl ector of the reactor, were also extracted, packed in cases or containers and removed, one part to a consolidation center and another to the high-level waste repository and subsequent shipments into long-term storage.More than 800 tons of MR equipment were dismantled in 2011-2014. Of this, more than 600 tons were radioactive wastes with total activity ~20 TBq. About 160 channels of the loop facilities and ~300 beryllium and graphite blocks with total 60 Co and 137 Cs activity ~55 TBq were removed from the reactor pool and fragmented. The high-level parts of the channels and blocks were packed in cases and placed in storage for cool-down; the medium-and low-level wastes were loaded into NZK-150-1.5P and KRAD containers and place in long-term storage at the Scientifi c-Industrial Association Radon. About 3000 m 3 of solid and 5000 m 3 liquid radwastes were removed from the territory; the total activity of the removed wastes reached 80 TBq.Remote controlled machines (Brokk Co., Sweden) were used to dismantle the equipment and handle the wastes. The intensely radiating parts w...

Examination of the waste held in a storage facility for high- and intermediate-level waste from the MR reactor

“…Работы по выводу из эксплуатации реакторов МР и РФТ выполняются в НИЦ «Курчатовский институт» в течение ряда лет . К настоящему времени демонтировано оборудование и активная зона реактора МР, аппаратура его экспериментальных петлевых установок [1], [2], удалена графитовая кладка реактора РФТ [2], [3] . В 2016-2021 гг .…”