Method for processing nuclear fuels containing silicon carbide and for unsheathing nuclear fuel particles

A processing method, silicon carbide technology, applied in the field of processing nuclear fuel containing silicon carbide and shelling nuclear fuel particles, can solve the problems that TRISO particles have not attracted enough attention and TRISO fuel has not been developed, and achieve the effect of short cooling time

Inactive Publication Date: 2009-09-09
COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] No treatment has been developed today that is suitable for irradiated TRISO fuel and allows overcoming the above-mentioned drawbacks, probably due to the fact that TRISO particles did not receive enough attention during the period 1975-2000

Method used

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  • Method for processing nuclear fuels containing silicon carbide and for unsheathing nuclear fuel particles
  • Method for processing nuclear fuels containing silicon carbide and for unsheathing nuclear fuel particles
  • Method for processing nuclear fuels containing silicon carbide and for unsheathing nuclear fuel particles

Examples

Experimental program
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Effect test

example 1

[0042] Example 1: Thermodynamic method of the action of SiC by a mixture of chlorine and oxygen

[0043] Thermodynamic calculations of the composition of the closed reactor system at equilibrium using the HSC software (Outokumpu) showed that a chlorine-enriched chlorine-oxygen mixture could be used to volatilize SiC in a single step.

[0044] attached figure 1 Depicted are regions of gas mixture composition that theoretically do not have any solid residues (darkest regions).

example 2

[0045] Example 2: Burning of Carbon

[0046] Combustion of carbon is effective from 400°C onwards. This was verified experimentally by thermogravimetric analysis. For this experiment, pure oxygen was used.

[0047] SiC volatilization was verified for powder, granule and bulk samples.

example 3

[0048] Example 3: Behavior of SiC powder in a mixture of chlorine + oxygen

[0049] Studies performed by temperature have shown that a temperature of 900°C allows quantitative attack of SiC.

[0050] The results of this study are reflected in Figure 2.

[0051] in order to achieve Figure 2a As a result, chlorine gas including 80% by volume (Cl 2 ) and 20% oxygen by volume.

[0052] in order to achieve Figure 2b As a result, chlorine gas including 80% by volume (Cl 2 ) and 20% oxygen by volume. The reaction was carried out at 900°C.

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Abstract

The present invention relates to a method for processing nuclear fuel containing fissile material, SiC, and optionally carbon, wherein said method involves contacting said fuel with a chlorine and oxygen mixture at a temperature lower than 950 DEG C, more particularly at a temperature between 400 and 900 DEG C, in order to remove the SiC and the carbon, if any, from said fuel. The method of the invention can be used for unsheathing TRISO or BISO nuclear fuel particles, i.e. the particles for confining the nuclear fuel in a sheath or sleeve, or for removing the SiC matrix of a heterogeneous SiC-matrix fuel. The present invention has numerous applications, mainly in the treatment of irradiated nuclear fuels.

Description

technical field [0001] The invention relates to a method of processing nuclear fuel comprising silicon carbide (SiC) and possibly carbon as a heterogeneous matrix. [0002] The invention particularly relates to a method for shelling TRISO (tristructural isotropic, isotropic three-layer coating) or BISO (bistructural isotropic, buffer isotropic, isotropic buffer double-layer coating) nuclear fuel particles. [0003] TRISO particles most commonly assume the shape of a sphere, typically of millimeter size, comprising an inner core of fissile material and a skin or shell that permits the confinement of the fissile material. The fissionable material of the inner core typically includes actinide oxides or, less commonly, actinide carbides or oxycarbides. The shell can be single layer or multilayer. In the most widely used TRISO nuclear fuel, the outer shell, from the inner core, includes: a layer of porous carbon that allows the expansion of fission gases; a layer of high-density ...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): G21C19/38G21C19/48
CPCG21C19/48Y02W30/50Y02E30/30G21C19/38
Inventor斯特凡·布尔格弗雷德里克·佩龙
OwnerCOMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES