Composite fuel material and method of its manufacture

 

(57) Abstract:

The invention relates to the production of composite fuel materials. The inventive composition of the fuel and the fissile material contains a substance on the basis of plutonium dioxide and an inert diluent. It also contains as fissile material oxides minor actinides - americium, and/or neptunium, and/or curium in the amount of 1-40% of the content of plutonium dioxide. As the inert diluent used porous zirconium carbide in the following ratio, wt.%: fissile 10-75; a carbide of zirconium - rest. The method of obtaining the composition of the fuel material includes preparation of fissile substances and inert diluent. Next perform multiple vacuum impregnation of the inert diluent ORGANOMETALLIC complexes, or sols or solutions of nitrates of plutonium and minor actinides. Produce two-stage heat treatment of the material. Advantages of the invention are to reduce the amount of waste, the reduction method and the possibility of regulating the composition of the fissile material in the production process. 2 S. p. f-crystals, 1 table.

Known fuel material with an inert diluent in the form of solid solution and with the following ratio of components: Rice Is 54.5% - ZrC - 45% (Rogozkin B. D. and others “Fuel of the solid solution of plutonium monocarbide and inert diluent for fast reactors”. Proceedings of the fourth interdisciplinary conference on reactor materials, may 15-19, 1996, , Dimitrovgrad, pages 328-340 /1/).

Since single-phase plutonium monocarbide corresponds to the composition of Rice0,88the application of the material has limitations. The excess of carbon over the above leads to the formation of single phase, worsening the compatibility of the core material with a steel sheath of the fuel element.

Closest to the claimed composition of the fuel material in essential characteristics is the fuel material, which contains plutonium dioxide as inert matrix - magnesium oxide (Kurina I. S. Moiseev, L. I. Obtain and study the properties of fuel pellets of the composition of PuO2-MgO”. Atomic energy of fissile material (no more than 15%) and therefore, low efficiency operation of the fuel rod. In addition, the material is expensive due to the complexity and multistage manufacturing.

The task of the invention to provide a composition of the fuel material, which will ensure the efficiency and safety of operation of nuclear reactors.

The technical result of the invention is to increase the concentration of fissile material in the composite fuel material, and therefore, the efficiency of the reactors through the use of the fuel rod with the cores of the composite fuel material with an inert diluent and in the possibility of regulating the composition of the fissile material.

This technical result is as follows. Composite fuel fissile material contains a substance on the basis of plutonium dioxide and an inert diluent. It also contains as fissile material oxides minor actinides - americium, and/or neptunium, and/or curium in the amount of 1-40% of the content of plutonium dioxide, and an inert diluent - porous zirconium carbide, in the following ratio, wt.%: dividing in yvod, that the claimed composition of the fuel is different from the known to the introduction of new components with special properties. As the inert diluent is used porous zirconium carbide with adjustable porosity.

In the source of information /2/ also described the method of preparation of the fuel material, which consists in the preparation of fine powders of inert diluent and fissile material, mixing them in a certain proportion, further joint compacting and sintering. The obtained tablet blanks require further mechanical processing, i.e., conducting dusty operations with highly radioactive plutonium material.

This solution is chosen as the prototype for the method of preparation of the composition of the fuel material, as it is the closest analogue to the set of essential characteristics.

The technical result of the method of preparation of the composition of the fuel material is in the exclusion of a number of operations in which waste is generated, the cheaper way and in the possibility of regulating the composition of the fissile material in the production process.

Technical t preparation of fissile substances and inert diluent. Then perform multiple vacuum impregnation of an inert diluent, which is used as a porous zirconium carbide, ORGANOMETALLIC complexes, or sols or solutions of nitrates of plutonium and minor actinides and their subsequent decomposition using the two-stage heat treatment.

For experimental verification of the composite material were used billet cores TVEL carbide zirconium different porosity - 35; 50; 82,5%.

The chemical composition of the original carbide blanks in the table.

Examples

Example 1.

Raw materials: ORGANOMETALLIC complex (IOC) with the content of plutonium Q=120-160 g/l; as an inert diluent - rods of zirconium carbide with a diameter of 5.9-0,5mm, 50-80 mm, porosity 55-65%.

Perform vacuum impregnation of the porous preform ORGANOMETALLIC complex in a sealed vessel. The residual pressure of 0.2-0.5 PA, the impregnation time of 10-15 min, the temperature of the liquid 20-50C.

The impregnated preform is dried. The residual pressure of 1-3 PA, a temperature of 80-100C, the drying time of 50-70 minutes

Then carry out the low temperature the/P>Next, produce high-temperature heat treatment. The residual pressure 1-310-3PA, time 60-80 minutes, the temperature of 1400-C.

Example 2.

Raw materials: Sol dioxide plutonium containing plutonium Q=200-600 g/l; inert diluent diameter of 5.9-0,5mm, 50-80 mm, porosity 55-65%.

Perform vacuum impregnation of porous workpieces Sol. The residual pressure of 0.5 to 0.8 PA, the impregnation time of 20-30 min, the fluid temperature 50-80C.

The impregnated preform is dried. The residual pressure 2-4 PA, a temperature of 60 to 90 ° C, the drying time of 80-120 minutes

Then carry out a low-temperature heat treatment of the samples. The residual pressure 3-510-2PA, the heat treatment time 60-80 minutes, the temperature of 450-S.

Next, produce high-temperature heat treatment.

The residual pressure 3-510-3PA, time 40-60 minutes, the temperature of 1600-C.

The impregnation and heat treatment carried out repeatedly until the desired content of plutonium dioxide in the pores of the preform.

Example 3.

Source materials: plutonium nitrate to plutonium concentration 400-1100 g/l; inert diluent diameter of 5.9-0,5mm, 50-80 mm, porosity 55-65%.

The impregnated preform is dried. The residual pressure of 0.1-0.3 PA, a temperature of 70-90 ° C, the drying time 60-120 minutes

Then carry out a low-temperature heat treatment of the samples in the interval 20-600C with a heating rate of 500-600 deg/hour and holding at 600C 30-60 minutes

Next, produce high-temperature heat treatment in the range of 600-1200C with a heating rate of 600 deg/hour, with exposure at 1200C 30-60 min and a residual pressure of 0.1 PA.

Eight cycles of impregnation dioxide content of plutonium in the porous sample is 2.9 g/cm3.

The invention solves the problem of disposal of highly radioactive waste of nuclear power, cheaper method of manufacturing a composite material, eliminating some operations. In addition, the use of the fuel rod with the cores of the composite fuel material with an inert diluent helps to ensure the efficiency of the reactors.

1. Composite fuel material containing fissile substance on the basis of plutonium dioxide and an inert diluent, characterized in that it additionally contains as a fissile material oxides minor actinides - americium, and/or neptunium, and/or curium in the amount of 1-40% ototoxin components, wt.%:

Fissile 10-75

Carbide zirconium Else

2. The method of obtaining the composition of the fuel material, including the preparation of fissile substances and inert diluent and implementation of heat treatment of the fuel material, wherein after preparation of the initial components perform multiple vacuum impregnation of an inert diluent, which is used as a porous zirconium carbide, ORGANOMETALLIC complexes, or sols or solutions of nitrates of plutonium and minor actinides and their subsequent decomposition using the two-stage heat treatment.

 

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