JPH068908B2 - Equipment for processing nuclear fuel materials containing impurities - Google Patents

Description

TECHNICAL FIELD The present invention relates to a treatment apparatus for an impurity-containing nuclear fuel material or a nuclear fuel material-containing material generated from a nuclear fuel processing facility. More specifically, the present invention relates to an apparatus for continuously separating an impurity component from an impurity-containing nuclear fuel material to purify and recover a nuclear fuel material, and an apparatus for continuously separating a material component from a nuclear fuel material-containing material to refine and recover a nuclear fuel material. It is a thing.

[Prior Art] Scrap powder such as grinding powder of sintered pellets is generated from a nuclear fuel processing facility. These powders are collected and reused. However, impurities are often mixed in these powders, and purification is performed to remove the impurities. Conventionally, such impurity-containing nuclear fuel material is usually purified by a chemical method such as solvent extraction after dissolving the impurity-containing nuclear fuel material in an acid.

On the other hand, in equipment materials for nuclear fuel production, for example, a molybdenum container is used as a container for sintering UO ₂ pellets, but since this container is heated at high temperature for a long time, not only the surface of the container but also the uranium not only inside the container Are diffused and invaded and contaminated. Therefore, decontamination of uranium is performed from a molybdenum container, which is usually performed by a chemical method disclosed in JP-B-59-33877, JP-A-60-255624 and the like.

Nuclear fuel substances include uranium, plutonium, and thorium, and impurities contained in the nuclear fuel substances include molybdenum, cadmium, lead, and sodium.
Further, as a material containing a nuclear fuel material, molybdenum can be cited.

However, since the above chemical method is a wet method, various waste liquids such as a filtrate are produced, and the waste liquid must be treated. This kind of waste liquid treatment has a problem that it is complicated and the treatment cost is high.

In order to solve this point, a fuel reprocessing apparatus for separating volatile fission products of spent fuel for a nuclear reactor by gas has been disclosed (Japanese Patent Laid-Open No. 53-8499). This device is a completely closed type cylindrical heating furnace, in which the sheared fuel containing sheath is put into the furnace, and the fuel is made into powder by heating and vibration and remains on the powdered fuel that has passed through the porous plate and on the porous plate. Saya is separated and taken out of the furnace through separate outlets.

[Problems to be Solved by the Invention] Therefore, the fuel reprocessing apparatus is intended to process only the fuel containing sheath, and it is difficult to process the impurity-containing nuclear fuel material of other general forms and shapes. .

An object of the present invention is to generate waste liquid from various forms of impurity-containing nuclear fuel material or nuclear fuel material-containing material,
It is an object of the present invention to provide a processing apparatus for continuously and surely separating and refining and recovering a nuclear fuel substance and impurities or materials by a dry method.

[Means for Solving the Problems] In order to achieve the above object, the configuration of the present invention will be described with reference to FIG. 1 corresponding to the embodiment.

The present invention relates to a heating furnace 1 of which both ends are open, which is formed so that a container 2 containing an impurity-containing nuclear fuel material or a nuclear fuel material-containing material 6 can pass from an inlet 1a at one end to an outlet 1b at the other end,
A means for simultaneously introducing the oxidizing atmosphere gas 7 from the inlets 1a and the outlets 1b at both ends of the heating furnace 1 and the oxidizing atmosphere gas 7 provided in the middle portion of the heating furnace 1 by heating the inside of the heating furnace 1 to contain the impurity-containing nuclear fuel substance or nuclear fuel. Impurity oxide or material oxide 8 that is selectively evaporated from the substance-containing material 6
And a lead-out pipe 4 which is led out together with.

It is preferable to provide the outlet pipe 4 with the filter 3 because the nuclear fuel oxide that evaporates can be solidified and collected. In order to solidify and collect this nuclear fuel oxide, it is preferable that the filter 3 is arranged in a temperature range that is lower than the melting point of the nuclear fuel oxide and higher than the melting point of the impurity oxide or the material oxide.

Further, it is preferable to provide the trap 5 at the outlet 4a of the outlet pipe 4 because the oxide led out from the outlet pipe 4 can be solidified and collected by natural air cooling or water cooling.

[Operation] When the impurity-containing nuclear fuel material or the nuclear fuel material-containing material 6 is accommodated in the container 2 and fed from the inlet 1a of the heating furnace 1, the nuclear fuel material or the material 6 is introduced into the heating furnace 1 in the heating furnace 1. The oxidizing atmosphere gas 7 converts the impurities into oxides that easily evaporate, and the impurity oxides or material oxides 8 evaporate and separate from the nuclear fuel material or material 6 while the container 2 moves in the heating furnace. Purified nuclear fuel material without impurities 9
Is taken out from the exit 1b.

In particular, by introducing the oxidizing atmosphere gas 7 through the inlet 1a and the outlet 1b at both ends of the heating furnace 1, the evaporated impurity oxides or material oxides 8 even if the heating furnace 2 is open at both ends.
Does not leak from the inlet 1a or the outlet 1b. Further, unlike when the oxidizing atmosphere gas 7 is introduced from either the inlet 1a or the outlet 1b, the evaporated impurity oxide 8 is not solidified near the outlet 1b having a low temperature or near the inlet 1a. As a result, the purified nuclear fuel material 9 at the outlet 1b is not recontaminated with the impurity oxide 8 or the impurity oxide 8 does not adhere to the new impurity-containing nuclear fuel material 7 at the inlet 1a.

[Embodiment] Next, an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, a passage for a container 2 is formed in the horizontal direction inside a core tube 1 which is a heating furnace of which both ends are open. The core tube 1 has an inlet 1a at one end and an outlet 1a at the other end.
b. The inlet 1a and the outlet 1b are provided on a straight line. The container 2 contains an impurity-containing nuclear fuel material or a nuclear fuel material-containing material 6. The oxidizing atmosphere gas 7 is simultaneously introduced with the same gas amount from both the inlet 1a and the outlet 1b by an air supply means (not shown).

A lead-out pipe 4 is provided at an intermediate portion of the core tube 1. The lead-out pipe 4 is detachably provided with a filter 3 for solidifying and collecting the nuclear fuel material which is extremely partially evaporated. Therefore, the filter 3 is arranged in a temperature range that is lower than the melting point of the nuclear fuel oxide and higher than the melting point of the impurity oxide or the material oxide. The outlet 4a of the outlet pipe 4 is provided with a trap 5 for solidifying and collecting the oxide led out from the outlet pipe 4 by natural air cooling or water cooling.

A method of separating impurities from the nuclear fuel material and refining and recovering the nuclear fuel material by the processing apparatus having such a configuration will be described.

First, when the impurity-containing nuclear fuel material 6 is housed in the container 2 and fed from the inlet 1a of the core tube 1, the nuclear fuel material 6 is introduced into the core tube 1 by the oxidizing atmosphere gas 7 introduced into the core tube 1. Turns into an easily evaporated oxide. As the container 2 moves in the core tube toward the outlet 1b, the impurity oxide 8 evaporates and the nuclear fuel material 6 is evaporated as shown by the broken line arrow in FIG.
Separate from. Purified nuclear fuel material 9 free of impurities is withdrawn from the outlet 1b.

At this time, the oxidizing atmosphere gas 7 is introduced from both the inlet 1a and the outlet 1b of the core tube 1 so that the evaporated impurity oxide 8 flows into the outlet tube 4. As a result, the impurity oxide 8 selectively oxidized and evaporated in the core tube 1 is guided in the direction of the outlet tube 4 and passes through the filter 3. The oxidizing atmosphere gas 7 entrained with the impurity oxide 8 contains the nuclear fuel oxide that has been evaporated only partly, but the nuclear fuel oxide is solidified and collected by the filter 3 depending on the arrangement conditions of the filter 3, and the impurity oxide 8 and the oxide are oxidized. The atmospheric gas 7 passes through the filter 3. The passed impurity oxide 8 is cooled in the trap 5 and solidified and collected. After the filter 3 is removed, the collected nuclear fuel oxide is separated and collected from the filter.

Here, the reason for introducing the oxidizing atmosphere gas 7 from both the inlet 1a and the outlet 1b of the core tube 1 will be described. If the oxidizing atmosphere gas 7 is introduced only from the inlet 1a at one end of the core tube 1, the oxidizing atmosphere gas 7 flows not only from the inlet 1a to the outlet 4a of the outlet pipe 4 but also from the inlet 1a to the outlet 1b. . In this case, the oxidatively evaporated impurity oxide 8 flows along with the flow of the oxidizing atmosphere gas 7 not only in the outlet 4a but also in the outlet 1b, and solidifies near the outlet 1b of the core tube 1 having a low temperature. However, it adheres to the refined nuclear fuel material 9 moving around the inside of the furnace or in the direction of its exit. This is also the case when the oxidizing atmosphere gas 7 is introduced only from the outlet 1b at the other end of the core tube 1, and as a result, the impurity oxide 8 that has been oxidized and evaporated has a low temperature.
Will solidify in the vicinity of the inlet 1a and will adhere to the nuclear fuel material 6 entering the inside of the furnace or the core tube. For the above reason, the oxidizing atmosphere gas 7 is introduced from the inlet 1a and the outlet 1b at both ends of the core tube 1.

In the above example, the description of the means for moving the container 2 is omitted, but as shown in FIG. 2, the containers 2 are successively put into the core tube 1 and the container near the inlet is indicated by the arrow in the next container. As indicated by reference numeral 10, the entire container 2 may be moved by pushing.

Further, as shown in FIG. 3, guide rollers 12 are arranged at the inlet and outlet of the heating furnace 1, a driving roller 13 is arranged below these rollers 12, and the endless belt 11 is wound around the rollers 12 and 13. The endless belt 11 may circulate inside the heating furnace 1. This belt 1
The circulation of 1 moves the container 2 from the inlet to the outlet.

Further, in the above example, the impurity-containing nuclear fuel material is contained in the container and separated into the impurity oxide and the nuclear fuel material. However, the nuclear fuel material-containing material may be contained in the container to separate the nuclear fuel material and the material.

[Effects of the Invention] As described above, the present invention has the following various effects by having the above configuration.

(1) Since it is a dry method, there is no need for waste liquid treatment unlike the conventional wet method.

(2) Since the nuclear fuel material containing impurities or the material containing nuclear fuel material is continuously introduced into the heating furnace and each component is separated and purified and recovered, the processing capacity and the efficiency thereof are large and economical compared to the batch system.

(3) Impurities or material components oxidized and evaporated in the high temperature part of the heating furnace center may migrate to the low temperature parts at both ends of the heating part, solidify and aggregate, and redeposit on the substance or the refined nuclear fuel material.
By introducing the oxidizing atmosphere gas from both ends of the heating furnace, the reattachment of impurities or material components can be prevented and the purification efficiency can be improved.

(4) The nuclear fuel oxide with a high melting point may evaporate only partly and be entrained in the impurities or the oxide evaporation component of the material, and the separation effect may be reduced, but the filter should be detachably installed in the outlet pipe. Thereby, only the nuclear fuel oxide can be collected by the filter, and the separation effect can be enhanced.

(5) By providing a trap at the outlet end of the outlet pipe, it is possible to solidify and collect the impurity oxide or the material oxide, which is the evaporation component discharged from the outlet pipe, by natural air cooling or water cooling.

(6) Impurity-containing nuclear fuel material or nuclear fuel material-containing material is placed in a container for processing and is passed from the inlet at one end to the outlet at the other end. Therefore, the impurity-containing nuclear fuel material or the material containing nuclear fuel material is disclosed in JP-A-53-8499. The fuel is not limited to the sheathed fuel shown in the publication, and can be processed relatively easily even in a general form and shape.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a processing apparatus according to an embodiment provided with a filter and a trap according to the present invention. 2 and 3 are schematic vertical sectional views of a processing apparatus in which a container is movably arranged. 1: Core tube (heating furnace) 1a: Core tube inlet (heating furnace inlet) 1b: Core tube outlet (heating furnace outlet) 2: Container 3: Filter 4: Outlet tube 4a: Outlet tube outlet 5: Trap 6: Nuclear fuel material containing impurities or nuclear fuel material-containing material 7: Oxidizing atmosphere gas 8: Impurity oxide or material oxide (evaporation component) 9: Purified nuclear fuel material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Tanaka, 622, Funaishikawa, Tokai-mura, Naka-gun, Ibaraki Prefecture Mitsubishi Nuclear Fuel Co., Ltd., Tokai Works (56) Reference JP-A-53-8499 (JP, A) JP-A-50-76661 (JP, A)

Claims (4)

[Claims] 1. An open-ended type which is formed so that a container (2) containing an impurity-containing nuclear fuel substance or a nuclear fuel substance-containing material (6) can pass from an inlet (1a) at one end to an outlet (1b) at the other end. heating furnace
(1), means for simultaneously introducing an oxidizing atmosphere gas (7) from the inlet (1a) and the outlet (1b) at both ends of the heating furnace (1), and provided in the middle part of the heating furnace (1) The oxidizing atmosphere gas
A discharge pipe (4) for discharging (7) together with an impurity oxide or a material oxide (8) selectively evaporated from the impurity-containing nuclear fuel material or the nuclear fuel material-containing material (6) by heating in the heating furnace. An apparatus for processing an impurity-containing nuclear fuel material and the like. 2. The treatment apparatus for impurity-containing nuclear fuel material according to claim 1, wherein the filter (3) is detachably provided on the outlet pipe (4). 3. The apparatus for treating an impurity-containing nuclear fuel material or the like according to claim 1 or 2, wherein a trap (5) is provided at the outlet (4a) of the outlet pipe (4). 4. The impurity-containing nuclear fuel material according to claim 2, wherein the filter (3) is arranged in a temperature range lower than the melting point of the nuclear fuel material and higher than the melting point of the impurity oxide or the material oxide. Processing equipment.