DE1614533A1 - Process for the production of nuclear fuel for nuclear reactors - Google Patents

Description

Patent application

Societe Beige pour! 'Industrie Nucleaire BELGONUCLEAIRE, S.A., Brussels / Belgium, 351 Rue des Colonies

Process for the production of nuclear fuel for nuclear reactors.

The invention relates to the manufacture of Fuel for nuclear reactors and in particular the production of granular fuel material, how it is used in the fuel rods.

Xm Generally, the fuel rods with fuel formed by grain material of different grain sizes or grain sizes filled drilling _t the content of which for the purpose of achieving a density of the fuel-hoheii material compacted by vibration is (shaking or vibration compaction).

The difference in dimensions between the grains (different grain sizes) is such that it allows the voids between the large grains

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to be filled in with grains of smaller dimensions · The overall density achieved is increased if the tube is subjected to a vibration treatment after its filling, as it is called under the name Vibrο compaction or vibration compaction is known.

In the case of the production processes for grains that have become known by the dry route, one assumes one more or less compacted fuel-material mass from which then a grinding or crushing. ' Process is subjected; the grains thus obtained are then selected according to their dimensions (fractionated, classified, separated), and the unused grinding residue is then fed back into the process, i.e. compacted again, grind, etc.

The productivity (efficiency) of this method from grains of large dimensions (coarse grain) is real very small (i.e. there is only a little coarse grain generated proportionally), which means several process runs of the grinding residue, which is not used, makes it necessary and expensive material investments or * leads to investing expensive material and a less efficient production method.

The present invention has for its object, the Recycliere ^ ,, so the multiple passage through the

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Avoid grains through the manufacturing process or at least reduce the number of repeated runs to a very low value «

The invention consists of a method of manufacture of nuclear fuel grains by dry route, such as those used for the manufacture of fuel rods and with the help of vibration compaction be compacted, this process thereby indicates that the coarse grain or the large grains made to measure (e.g. with the same predetermined Dimension or predetermined - e.g. slightly differing - dimensions).

These grains (coarse grain) can be produced by any known means, for example with the help of a mechanical or hydraulic press.

The smaller sized grains (central and / or Fine grain) can according to the known method, as above described *, or they can also be prepared in the same way by grinding the according to the process made in accordance with the present invention Coarse grains are produced.

The following is, only as a non-limiting embodiment of the invention, the manufacture of a Fuel rods described, which are filled with grains is, according to the procedure according to the present

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discovery were made.

A mass or quantity of powder formed from a mixture of uranium oxide and plutonium oxide, is made with the help of a mechanical press compressed (pressed), such that grains of 2.9 mm in diameter arise.

These grains are then for the duration of 2 hours in an oven at ⁰ C under hydrogen I7OO 'atmosphere sintered (fritted). After the sintering process, the grains still have a diameter of approximately 2.5 mm.

The part of these grains is then ground in a crushing mill (roller mill) in such a way "that" is given grains of smaller dimensions, which vary between 250 microns (A) and 50 microns (M. / £ - 1/1000 mm).

A stainless steel pipe with an inner diameter of 7 mm is then filled with a mixture composed of 60 % grains of 2.5 mm (diameter or grain size) and ko% grains of dimensions (diameter) of 250-50 microns. The pipe is then shaken (vibration treated) in such a way that a high density of the fuel material (in the pipe) is achieved.

It should be noted that this example is only for

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Clarification is given, and that various modifications can be made

Claims -

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Claims (5)

4921/30 Bu / Wa - 6 - 30, May I967 16U533 ** claim claims' " 1. Method of making nuclear fuel grains by dry route, such as those used for fuel rods and with the help of vibration compression "are compressed, thereby marked c h η e t that the coarse (large) grains are made to measure using known means. 2. The method according to claim 1, characterized in that the same coarse grains or approximately the same dimensions or diameter are given * 3. The method according to claim 1 and / or 2, characterized in that the coarse (large) Grains can be made with the help of a mechanical press. 4. The method according to one or more of the claims 1 to 3 "characterized ge ke η η ζ calibration net, that grinds a TEI1 the coarse grains or the rough grain quantity such that grains _t lesser dimensions (diameter) generated * 5. Grain or the amount of grain from fuel material for nuclear reactors, like this one used in fuel rods . lind with the help of vibration compression (vibration bait Rütteiverdichtüng) is earned «thereby 009822/0821 . . '. . - BAD ORXANAL '. '■■■' ■ · '· ■ - 7 - 4921/30. Bu / Wa - 7 - 30, Mat I967 gekennseic h η et that the grains after Measure according to the method according to claim 1 and / or claims 2 and 3 are produced. 6 * fuel rod, thus g e k e η η ζ ei c h η e t, that it is at least partially filled with grains produced according to claim 5 " 7 · Fuel rod according to claim 5 and / or 6, characterized in that it is η ζ e ich. η et, 'that it contains approx. 60 % coarse grain, for example with dimensions of approx. 2.5 mm, and approx. 40 % medium and / or fine grain, for example with dimensions of 50 to 25Ο microns. 009822/0621