FSUE Moscow United Ecological and Technological and Scientific Research Center of Radioactive Wastes` Neutralization and Environmental Protection (FSUE Mos NPO “Radon”):

Tkachenko A. V., First Deputy Director, Candidate of Engineering Sciences, e-mail: radonalex@mail.ru

Litinskiy Yu. V., Leading Researcher, Candidate of Engineering Sciences

Near-surface storages were historically the most widespread facilities for storage of low and intermediate radioactive waste levels. Operating experience in conditions of a continental climate with cyclic seasonal freezing and thawing of grounds and underground constructions shows that the permeability of grouting cement and engineering barriers increases in time due to the cracks and cement destruction caused by these cycles. It is accompanied to the water accumulation in facility, leaching of radionuclides and their migration out of the storage. The new type of long term storage/disposal facility is developed on the basis of Large Diameter Borehole (LDB) to minimize these effects and increase the ecological safety of near-surface radioactive wastes` storage facilities as well as to use the operating territory in more effective manner. Two LDB-type storages (LDB-1 and LDB-2) with the internal diameter of 1.5 m and the depth near 40 m are constructed at the site of SUE MosSIA "Radon". In October 2003 LDB-2 was loaded for the first time with low and intermediate level radioactive wastes,, conditioned in 36 standard steel drums. In May 2006 LDB-1 was loaded with 90 similar drums. Later, the both Large Diameter Boreholes were licensed for radioactive wastes` storage. Since 2003 a complex of manual observations within the storage, in engineered barriers and in near field has been carried out to assess the tightness of construction, its temperature and radiation rate. Inside is the air humidity. Outside is the borehole and ground water level.