Major loop circulation device used for nuclear energy system

Abstract

The invention discloses a major loop circulation device used for a nuclear energy system. The device comprises a container, a core, heat exchangers, a main pump, heat separator plates, a grid plate collecting box and a pipeline; the heat separator plate divide the inner chamber of the container into an external heat tank and an external cold tank, every heat separator plate is a hollow structure, every heat separator plate is provided with a heat separator plate inlet end and a heat separator plate outlet end, the heat separator plate inlet ends are arranged at the cold tank side of the lower portions of the heat separator plates, and the heat separator plate outlet ends are arranged at the cold tank side of the upper portions of the heat separator plates. The device enhances the flow of a coolant in the cold tank, and provides a cold tank and heat tank separation function under normal running and accidental conditions of a reactor; and the device inhibits heat layering in the heat tank under a shutdown condition of the reactor, enhances the natural circulation ability of the reactor, and effectively improves the economy, the reliability and the safety of the reactor.

Description

technical field [0001] The invention relates to a reactor cooling device technology, in particular to a main circuit circulation device for a nuclear energy system. Background technique [0002] In the pool-type liquid heavy metal cooling reactor, the melting point of the liquid heavy metal is relatively high (the melting point of liquid lead and bismuth is 125°C, and the melting point of liquid lead is 327°C), while the melting point of liquid sodium in the sodium-cooled fast reactor is 98°C, and the liquid heavy metal is relatively high. The high melting point makes it necessary to maintain a relatively high temperature in each area of ​​the reactor pool to prevent partial solidification of the coolant, and solid coolant particles may cause blockage and other accidents after entering the core. However, under shutdown conditions, due to the decrease of the coolant flow rate, the coolant in some low flow rate areas may also partially freeze due to insufficient oxygen control...

AI Technical Summary

Problems solved by technology

If this cold and hot pool separation method is used in a pool-type liquid heavy metal cooling reactor, it can ensure that the coolant on the thermal partition and the wall of the container is fully mixed, but the flow rate of the coolant inside the thermal partition decreases under shutdown conditions. Small, can not ensure the normal heat insulation effect of hot and cold sodium pools, and the coolant in some low flow rate areas may also partially freeze due to insufficient oxygen control effect

[0004] The second is the single-layer thermal insulation design adopted by European ALFRED and XADS. This scheme can only be used in liquid heavy metal cooling reactors with small temperature differences between the cold and hot pools. If the temperature difference between the cold and hot pools is large, thicker thermal insulation must be used. Plate design to reduce the problem of thermal stress in the thermal partition, which requires a larger space in the stack, increases the amount of coolant, and is not economical

At the same time, the presence of cold liquid heavy metals will also reduce the flow rate of natural circulation and adversely affect the cooling of the core after an accident shutdown

From the point of view of the integrity analysis of the equipment structure, the emergence of fast reactor thermal stratification is not good for the reactor vessel and some reactor internal components, which will cause obvious thermal stress in these components inside the structure, and pose a hidden danger to the safe operation of the reactor.

The phenomenon of thermal stratification can also cause the uneven distribution of oxygen concentration in the liquid heavy metal coolant, resulting in chemical control and structural material corrosion problems. Compared with sodium-cooled fast reactors, the chemical control and structural material corrosion problems of liquid heavy metal cooled reactors are more serious. serious

Sodium-cooled fast reactor "Wenju" reactor, China Experimental Fast Reactor CEFR, pool-type liquid heavy metal experimental device CIRCE, etc. mainly study thermal stratification through numerical analysis or experimental means, and have not retrieved related device designs for suppressing thermal stratification in thermal pools Program

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