Codes of new generation for safety justification of power units with a closed nuclear fuel cycle developed for the “PRORYV” project

The article describes the status of development of codes of new generation for the “PRORYV” Project by the end of 2019: twenty-five commercial-grade software products to justify design solutions and safety of power units with fast neutron reactors and liquid metal coolant (sodium and lead) in a closed nuclear fuel cycle. The developed system of codes is multi-physical and multi-scale that allows performing both calculations of the whole installations and high precision calculations of their individual elements. The developed codes offer unique features. Twelve developed codes have already been certified by Rostechnadzor, and six more have been submitted for certification. In addition to creating the software products, a large-scale work is being carried out to conduct experimental studies for code validation that meet modern requirements imposed by the codes: unique measurement techniques have been created; experimental data on flow characteristics of heavy liquid metal coolant (HLMC) in a fuel assembly simulator have been obtained, as well as of “gas-HLMC” interphase interaction after inert gas injection in HLMC and characteristics of heat exchange between the inert gas and HLMC. The results are already used for validation of system and CFD codes used in the “PRORYV” Project.

Potential radiological risk for the population during implementation of the Rosatom Proryv project. Part 2. Radiation detriment assessment

Nuclear power is effective and safe source of electricity. Meanwhile, uranium reserves in the earth's crust will run out in 100 years with the development of traditional nuclear reactors. The Rosatom “Proryv” project implementation will allow multiplying fuel sources for the new genera-tion nuclear power through the closing fuel cycle. Radiation safety of the new nuclear powers should be based on the state of the art Russian national and international regulations, as well as on predicted radiation doses, estimates of potential radiation risks and radiation detriment of the public. Developed methods for computational analysis of possible doses of estimates of radia-tion risks and population-based detriment, associated with atmospheric fallouts of radioactive substances from the BREST-OD-300 reactor, corresponds to the currently recognized approach-es to evaluating safety of nuclear energy facilities. Developed method for radiation detriment es-timating is in accordance with ICRP recommendations. It allows making assessment of radiation-associated health effects for Russian population with account of patients’ quality of life provided by the current health care system. The analysis of possible radiation doses and potential radia-tion risks shows that the upper 95% confidence bound of radiation detriment for the critical group of population in the town of Seversk (girls of 5 years of age) even in the event of beyond design basis accident at the reactor equals 1.1610-5 year-1, and does not exceed the radiation risk limit of 510-5 years-1, established by Russian national radiation safety regulations NRB-99/2009 for the population during normal operation of ionizing radiation sources. In the event of an accidental situation on the Brest-OD-300 reactor, the average estimates of radiation risks for the population living within the 30-km zone around the JSC “Siberian Chemical Combine” will generally remain in the range of negligible risk and will not exceed the level of 10-6 year-1.