Mixed oxide pellet sintering atmosphere control device

Abstract

Belonging to the technical field of fast neutron reactors, the invention discloses a mixed oxide pellet sintering atmosphere control device. The device comprises a gas cylinder, a drying pipe, flow valves, a bubbler, a thermometer, a pressure control apparatus, a gas mixing tank, a moisture meter, a sintering furnace and a control cabinet. Specifically, the gas cylinder is filled with a hydrogen-argon mixed gas, and the outlet of the gas cylinder is connected to the drying pipe to dry the moisture in the hydrogen-argon mixed gas; the flow valves fall into a first flow valve and a second flow valve; one end of the drying pipe far from the gas cylinder is connected to one ends of the first flow valve and the second flow valve respectively through two connecting pipelines, wherein the other end of the first flow valve is connected to the inlet of the gas mixing tank, and the other end of the second flow valve is connected to the bubbler. The device provided by the invention has the beneficial effects of accurate oxygen potential control, simple structure and control process, and high economical efficiency, and can meet batch production.

Description

technical field [0001] The invention belongs to the technical field of fast neutron reactors, and in particular relates to an oxygen potential control device for sintering atmosphere of mixed oxide pellets. Background technique [0002] When fast reactor MOX pellets are manufactured, the oxygen-to-metal ratio O / M of pellets is a very important technical index, and the oxygen-to-metal ratio is required to be between 1.96 and 1.99. Because the oxygen-to-metal ratio affects various thermophysical properties of fuel pellets, including thermal conductivity, thermal diffusivity, density, etc., it also has an important impact on the interaction between cladding and pellets. An excessively high oxygen-to-metal ratio will accelerate the oxygen diffusion rate at the contact point between the cladding and the pellet, accelerate the corrosion of the cladding, and reduce the service life of MOX components; too low an oxygen-to-metal ratio will lead to the generation of a second phase in ...

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Problems solved by technology

The addition of oxygen requires complex calculations and it is difficult to control the sintering process, because oxygen and hydrogen will react at high temperatures; the method widely used by technicians in various countries is to add a certain amount of water gas to the cylinder of hydrogen-argon mixed gas , but the water vapor may corrode the gas cylinder, so only the more expensive aluminum alloy cylinder can be used

Moreover, depending on the water content, the gas bottling pressure is also much lower than that of dry gas (dry gas is 10MPa, and moisture containing 800ppm of water can only be 4-5MPa, and the pressure is too high will cause water vapor to liquefy). The amount is also reduced accordingly, which cannot meet the demand for large quantities of production

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