No abstract available

No abstract available

No abstract available

[en] A number of specific tasks arises during decommissioning of the reactor with liquid metal sodium as a coolant. The implementation of these tasks affects directly safety of the reactor unit and population near the installation. The high level of technology, development of technical decisions and trained personnel are needed to observe present requirements of normative documents. Peculiarity of liquid metal sodium as a coolant of the BN-350 reactor consists in its high chemical activity, fire risk, and high level of radioactivity. The strategy of management of such substance is drawn up on a stage-by-stage decreasing of tbe level of its danger for people and environment. The first stage consists of sodium cleaning from radionuclides that determine its radioactivity. Cesium-137 is the main isotope among others. The world wide practice came to the conclusion that the most effective method of cleaning from cesium isotopes is adsorption on carbon materials. The second stage includes the draining of cleaned sodium into tanks of storage. This stage demands development of special technological decisions and equipment to remove fully liquid metal coolant from the reactor vessel and circuits' loops. The third stage of sodium treatment consists of processing of drained sodium in chemically passive substance. There are different technologies in the world; their selection is made in the basis of detailed analysis taking into account many factors. For the BN-350 reactor at present is assumed sodium processing into sodium hydroxide with the following transfer into sodium from acceptable for disposal. During the fourth stage remains of sodium are removed from inner parts of the reactor unit. The location of sodium after the bulk draining depends on design particulars of the reactor and circuits. The given report contains the detailed description of each of four stages with indication of existing technologies as applied to the BN-350 reactor. The intended way of liquid sodium coolant transfer into safe form is pointed out. The work is implementing under technical and financial support of State Department and Department of Energy USA

[en] This paper describes the results of investigations of 08Cr16Ni11Mo3 (AISI 316 steel analogue) austenitic stainless steel irradiated in BN-350 breeder reactor at irradiation conditions close to that for Light Water Reactor (LWR) Internals. The pores were found in 08Cr16Ni11Mo3 steel irradiated at temperature 280 deg. C up to rather low damage 1.3 dpa and with dose rate 3.9 x 10^-9 dpa/s. There were obtained dose rate dependencies of yield strength, ultimate strength and ductility for 08Cr16Ni11Mo3 steel irradiated up to 7-13 dpa at 302-311 deg. C. These dependencies show a decrease in both yield strength and ultimate strength when dose rate decreases. There was observed an apparent decrease in total elongation when dose rate decreases, which was presumably connected with the pores formation in the steel at low dose rates. (authors)