Method for the long-term storage of spent nuclear fuel and cooling and storage tank for the implementation thereof

Abstract

The group of inventions relates to the nuclear power industry. A method for the long-term storage of spent nuclear fuel consists in unloading fuel whole within a removable assembly without dismantlingthe reactor core, and placing it in a cooling and storage tank disposed in a pit having a cooling system and being filled with a liquid lead-bismuth eutectic alloy, in which conditions are provided for maintaining the liquid state of the lead-bismuth alloy and for monitoring the temperature thereof for decay heat removal; removing the tank and placing same in an on-site cask without exceeding thepermissible temperature of the lead-bismuth alloy, with heat decay removal taking place until the lead-bismuth alloy hardens in the tank; transferring the tank to a transport cask without the implementation of further decay heat removal measures. A cooling and storage tank is also claimed. The group of inventions makes it possible to simplify and reduce the length of the refueling process in thecase of nuclear fuel with a high level of decay heat.

Description

technical field [0001] The group claimed by the present invention belongs to the nuclear power industry, namely, to methods of processing spent fuel (spent nuclear fuel), and above all, to reactors with lead-bismuth coolant, which operate without partial refueling. Background technique [0002] A method of long-term storage of spent fuel is disclosed in RU Patent No. 2550092; the method involves placing spent fuel assemblies in steel finned tanks pre-filled with liquid lead. To do this, position each box in a vertical electric furnace. Each tank was then removed from the electric furnace and placed into an air-cooled battery, along with the spent fuel assembly submerged in liquid lead. Due to the high melting temperature of lead (327°C) and the low temperature of the cooling air, the lead solidifies rapidly, and due to the thermal conductivity of lead, the residual heat of the spent fuel assembly is transferred to the cooling air through the tank wall. The disadvantage of ...

AI Technical Summary

Problems solved by technology

The disadvantage of the above method is that due to the high value of the installed capacity utilization coefficient, it is not suitable for civil nuclear power plant reactors due to the high level of residual heat, which is a characteristic of the operating mode of civil nuclear power plants, and after the completion of the service life, the active area of ​​the reactor cannot be extended time exposure to provide waste heat drop which may result in forced shutdown of the corresponding reactor