The main results of startup operations and experimental operation of a facility for decontaminating radioactively contaminated soil are presented. The facility was developed on the basis of water-gravity and mechanical separation of soil, making it possible to separate the soil into fractions according to grain size and to identify and remove the finely dispersed fraction which is characterized by high specific activity and in which up to 90-95% of the radionuclides accumulate. The salient features of the technological and instrumentation scheme of the facility are described, and an assessment of its cost-effectiveness is presented.

Efforts to develop design materials and preparations for liquidation of old radwaste repositories at the Russian Science Center KurchatovInstitute have revealed problems due to the lack of archived information on the salient structural features of the repositories and the wastes placed there as well as due to the inadequate development of the technical and technological support base for restoration work. The technical approach implemented during the preparation for liquidation of the repositories is described. The sequence of operations is presented, and the technological and technical means are described. The problems of the technological support for inspection of the repositories are analyzed.Old radwaste repositories at the Russian Science Center Kurchatov Institute were liquidated and the sites were restored in 2002-2006 [1]. The work on developing the design materials and preparations for liquidation of the old repositories revealed problems due to inadequate technological and technical underpinnings for this work.The present article expounds the approach that was implemented when the old repositories were inspected and opened up and prepared for liquidation. It describes the technology and technical solutions and discusses technological support problems. Survey of Old Repositories and Their Preparation for Liquidation.Since there was no information on the salient structural features of the repositories and the radwastes placed in them, the preparations for extracting the wastes and liquidating the repositories were made in the following sequence:• development and coordination of a plan for exploratory drilling and surveying of a repository; • exploratory drilling of the marginal zone and waste body; • radiation and visual inspection;• removal of the fill-up soil from the top cover of the repository; • partial unsealing, destruction, and removal of the top cover. The technical means and technology for exploratory drilling, surveying, and unsealing the old repositories were chosen taking into account the salient structures which were found and the state, composition, and activity of the wastes contained in the sites. All work was performed with continual dosimeter monitoring of the zones, the volume activity of the air, and the radiation conditions on the repository as a whole.

Abstract. In a period between 1943 and 1974 radioactive wastes were temporary buried on a special site on the territory of RRC "Kurchatov Institute". The site monitoring held since the end of the 80s showed that contaminants are located not only on the surface and in the ground but they have also spread in groundwater. The paper presents preliminary results of the work on development of numerical models of radioactive contamination migration the waste disposal site. The objectives of the work were to evaluate the existing contamination plume, to determine mechanisms of contaminant migration on the site and to develop a numerical model of radioactive contamination transport that would allow correctly predicting further plume spreading for making necessary engineering decisions. Based on laboratory findings and radiation monitoring data obtained at the waste disposal site and its adjacent areas, there were determined the site hydrogeological structure and parameters, and a geoinformation database was developed. Three-dimensional numerical models of groundwater flow (using the MODFLOW code) and mass transport (using the MT3DMS code) were built and verified against field measurements. Using these models, preliminary predictions of radionuclide migration from the waste disposal site were made.

Shipping out the spent fuel of the research reactors at the Institute for reprocessing is examined. The spent fuel is characterized by a great diversity of structural characteristics of the fuel assemblies and fuel elements, fuel compositions, and the enrichment, burnup, and cool-down times of the fuel as well as the state of the components of the assemblies and the structural materials. A classification and quantitative indicators of the accumulated spent fuel from the standpoint of the modern state of its reprocessing technology and the requirements for delivery to the Mayak Industrial Association are presented. The structural features of the TKU-19 and -128 shipment containers are presented, and the loading of spent fuel assemblies into them for shipment to reprocessing is described. The plans and goals of further work on the removal of spent fuel from the Institute's territory are presented.Twelve research nuclear reactors, about 20 experimental critical and subcritical nuclear stands, hot materials science laboratories for performing research with irradiated nuclear fuel, and some other unique physical factilities have operated as part of the experimental base at the Russian Science Center Kurchatov Institute [1, 2]. As a result of many years of experimental operation of the reactor base, a substantial amount of spent nuclear fuel with total activity exceeding 10 16 Bq has accumulated in the course of various scientific programs. This high level of activity is what dictates the urgency of removing this fuel from the Institute's territory to reprocessing facilities.Storage Conditions, Characteristics, and Classification of Spent Fuel. The irradiated fuel is primarily in the form of spent fuel assemblies, fuel elements, and their fragments in research reactors which were disassembled at different times: RFT, IRT, Romashka, Enisei, VVR-2 and OR, MR operated in the final shutdown regime, and the IR-8 and rebuilt OR which are currently operating.After being off-loaded, the irradiated fuel was put into temporary storage sites at the Institute, which were built so that the reactors could meet their operational requirements and that the spent fuel is handled safely. The technical state of the storage sites meets the modern nuclear and radiation safety as well as physical protection requirements. Spent IR-8 fuel is located in a storage pond at the reactor site; IRT, RFT, and MR fuel is located in a centralized dry storage facility on the main site of the Institute; Romashka and Enisei fuel is located in a dry storage facility of complex "R" as well as on the main site; VVR-2 and OR fuel is located in storage ponds of a complex of research reactors and critical stands (Gazovyi Zavod complex) that is located on an auxiliary site at the Institute.

The salient features of the organization and execution of the work performed to remove radioactive wastes from and rehabilitate ten old repositories located on a special site of the Institute, which were distinguished by their design and the form and composition of the wastes contained in them, are described. The old repositories were located close to a housing development, so that special attention was devoted to the choice of technologies and technical means used for the rehabilitation. The technical approach and the sequence of operations are presented, and the technology and technical means are described. The problems of providing the proper technological equipment for this work are analyzed.The present paper describes the approach which was implemented for removing wastes and for liquidating old repositories located on a special site of the Institute, describes the technology and technical solutions deployed, and discusses the problems of providing the proper technological equipment for this work [1,2].Technological Sequence of the Operations. Waste extraction and liquidation of old repositories were performed in the following sequence:• development and coordination of the project; • opening and removing the top cover; • removing wastes from the repository, sorting the wastes, including according to the γ-ray dose rate, and loading into certified containers; • examining and liquidating the structures; • performing a final radiation survey of the foundation; • sorting and removing contaminated soil from the pit; • documenting the work performed and processing the paperwork showing that the rehabilitation work has been completed; • backfilling the pit with clean soil. All work was performed with continual dosimetric monitoring of the work zones, monitoring of the activity of the air, and monitoring the radiation conditions on the storage sites as a whole. Dust suppression was used to keep the radionuclides in air at a minimum.