In the operation of sodium-cooled fast reactor, accident caused by the leakage and combustion of liquid sodium is common, and it is a pivotal and difficult problem in research, construction and operation of sodium-cooled fast reactor internationally. In actual operation of sodium-cooled fast reactor, liquid sodium in sodium fire accident is difficult to form fog but mainly in columnar flow form due to low operation pressure and thermal insulation material wrapping the pipe, so experimental research about columnar fire is of much more practical significance. This paper focuses on combustion property on sodium column fire in the sodium-cooled fast reactor. Liquid sodium with high temperature will be poured into the combustion room via pouring high pressure nitrogen into sodium storage tank when solid sodium has been heated to enactment temperature; liquid sodium with high temperature will burn at combustion room with air forming sodium column fire. Initial temperature of sodium jet is about 200°C in experiment and spurt pressure is 0.2MPa, spurt flow is about 0.4–0.6m3 each hour. Temperature fields in combustion tank space and the catch plate in the bottom are measured through dozens of thermocouple distributed in combustion tank. No atomization phenomenon would exist in the pure sodium columnar fire in the space, the atomized fire triggered by splashed sodium from sodium stream striking the admittance plat and generate more than the high temperature of 900°C.

In order to verify the effect of the combined restraint form of straight strip and corrugated strip on the heat transfer capacity of shell-tube heat exchanger with natural circulation. The physical model and mathematical model of the local heat exchange section of the heat exchanger are established by using ICEM and Fluent to carry out numerical simulation. The calculation results of three-dimensional flow field and temperature field of the heat exchange section are solved and analysed to obtain the resistance characteristics of the tube bundle of shell-and-tube heat exchanger under the restriction of corrugated strip and straight strip with natural circulation and the influence at the temperature field.

Since sodium leak and sodium fire belongs to incidental accident in fast reactor. This paper made the simulation research on sodium droplet combustion, which was the most fundamental one of the analysis on sodium spray fire. Referencing to the sodium droplet combustion experiment, this paper made improvement in the traditional model of the sodium droplet and researched on the initial temperature and oxygen fraction on oxidation behavior of sodium droplet. This paper used the new spherical model with cones on the sodium droplet surface and improved the spherical model used in the traditional calculation of sodium droplet. This made the simulation was closer with the actual combustion situation. According to the characteristics of the reaction between the sodium and oxygen, this paper modeled sodium droplet combustion process, which was divided into three stages, namely the surface oxidation stage, pre-combustion stage and combustion stage, set up the mathematical model, compiled the calculation program and got the regulation of the sodium droplet temperature changed with time under different initial temperatures (200–500 °C) and different oxygen fractions (4–20%). This program was validated with the sodium droplet combustion experiment. Through using the proportion γ of the sodium mass participated in the oxidation reaction to vaporizing reaction in the unit time, under the different conditions of sodium droplet combustion, this paper used different γ in different reaction stage, got the simulation results, which were consistent with the experimental data and analyzed the changing regularity of γ.

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