JPS6070398A - Method and device for removing tritium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention is based on tritium (radioactive tritium, hereinafter referred to as T
At facilities that handle compounds containing tritium compounds (hereinafter referred to as tritium compounds), the air containing tritium compounds is oxidized by a catalytic reaction and converted into tritium water, and then the air containing tritium compounds is converted into tritium water in a drying column filled with a desiccant such as zeolite. The present invention relates to a method and apparatus for adsorption removal.

In the present invention, the tritium compound means hydrogen containing T such as HT or T2, water containing T such as HTO or T2O, or hydrocarbon containing T such as CH3T or C2H3T.

In the present invention, tritiated water is water containing T such as HTO or T2O, or water vapor thereof.

In general, the method for removing tritium compounds is to convert all tritium (usually gaseous hydrogen, hydrocarbons, and water) compounds in the air into water using an appropriate oxidation catalyst, and remove the tritiated water by adsorption with a desiccant. However, if a drying column filled with a desiccant such as zeolite is used for a certain period of time, the adsorption capacity of the desiccant decreases. When the adsorption capacity has decreased in this way, a method has been taken to regenerate the desiccant by removing tritiated water by dehydrating the desiccant. This regeneration method is carried out by removing the drying column to be regenerated from the tritium removal system, or by operating a valve while it is still incorporated in the above tritiated water, but in either case, a closed circuit as shown in Figure 1 is formed. It is done as follows. That is,
The air circulating in the closed circuit by the circulation pump 6 is heated to 150 to 250C by the preheater 1 and flows into the drying column 2, and the drying column 2 is further heated to 150 to 250C by the heater B.
Tritium water adsorbed on the desiccant is desorbed by heating to 5DC. The air containing tritium water thus flows into the cooler 4 maintained at a temperature of θ to -55U.

After the tritiated water is condensed and removed, it flows into the tritiated water receiving tank 5 and is treated as waste liquid.

In this method, a small amount of tritiated water still remains in the circulating air after treatment in the cooler. That is, there are cases where a small amount of tritiated water remains in the circulating air due to the saturated water vapor pressure at the processing temperature of the cooler and is circulated in the closed circuit via the circulation pump.

In such cases, the tritiated water can theoretically be completely removed by lowering the processing temperature in the cooler, but there are issues with the cooler's capacity, clogging due to freezing of the tritiated water and condensation of air components, etc. In addition to causing problems, heat loss also becomes a problem, and the economic disadvantage cannot be ignored (・.

It is an object of the present invention to maintain the processing temperature in the above-mentioned cooler relatively high to overcome the drawbacks of the prior art.

The present invention connects a tritium handling facility, an oxidation catalyst bed, and a tritiated water removal circuit in series, and in the tritium water removal circuit, a preheater-drying column A, a cooler, and a preheater-drying column B are connected in parallel. (a) The pulp is manipulated to form a circulation circuit consisting of a tritium handling facility, an oxidation catalyst bed, a preheater and drying column A, and air is circulated through the circulation circuit to remove waste generated from the tritium handling facility. The tritium compound is introduced into the oxidation catalyst bed together with the circulating air, the tritiated compound is converted into tritiated water, and the tritiated water is introduced in the form of steam into the preheater-drying column A together with the circulating air to convert the tritiated water into the preheater-drying column A. (h) adsorbing at least the preheater-drying column A, the cooler and the preheater-drying until the adsorbent to the drying column is at or near the breakthrough point; The pulp is manipulated to form a circuit through column B and either bypassing the tritium-handling facility or through the tritium-handling facility, while circulating air and heating drying column A. desorbing tritiated water from the adsorbent, condensing most of the tritiated water in a cooler, and adsorbing the remaining tritiated water in a drying column B;
thereby regenerating drying column A and (C) manipulating the pulp to form a circuit consisting of a tritium handling facility, an oxidation catalyst bed, and a preheater and drying column B, and circulating air through the circuit. , the tritium compounds generated from the tritium handling facility are introduced into the oxidation catalyst bed together with the circulating air, the tritium compounds are converted into tritiated water, and the tritiated water is introduced in the form of water vapor into the preheater-drying column B together with the circulating air. and adsorb the tritiated water onto the drying column, continuing the operation until the adsorbent in drying column B is at or near the breakthrough point, and (CL) then at least the preheater-drying column B, Cooler and Preheater - Manipulating the pulp through drying column A and forming a circuit that does not pass through the tritium-handling facility or through the tritium-handling facility, while circulating air and heating drying column B. Tritiated water is desorbed from the adsorbent in the drying column, most of the tritiated water is condensed in a cooler, and the remaining tritiated water is adsorbed to drying column A, thereby regenerating drying column B. This invention relates to a continuous tritium removal method that consists of repeating the following steps.

The present invention also connects a tritium handling facility, an oxidation catalyst bed and a tritiated water removal circuit in series, the oxidation catalyst bed serving to convert tritium compounds into tritium water;
In the tritium water removal circuit, a preheater and a drying column, a cooler, a preheater and a drying column are connected in parallel, a tritium water receiving tank is connected to the cooler, and a tritium handling facility, an oxidation catalyst bed, and A circuit or tritium handling circuit between any one of two preheaters and drying columns and passing through at least one preheater and drying column, a cooler, and the other preheater and drying column and not passing through a tritium handling facility. Concerning a continuous tritium removal device in which the pulp is installed so as to form a circulation circuit through the facility.

Hereinafter, the present invention will be explained in detail according to the embodiment shown in FIG.

■ indicates a tritium removal device, 11 indicates a tritium handling facility, drying columns 14 and 20 are filled with new or regenerated zeolite adsorbent, and air containing tritium compounds leaked at the tritium handling facility π ( air to be treated) is tritium handling facility -v1-
Circulation pump 11 - oxidation catalyst bed 12 - V, V3 - preheater 1
Filter drying power ram 14-v4. v5-Dew point meter 21-V, 4
-Circulates in the closed circuit of the tritium handling facility ■ to form an adsorption system. At this time, all other valves are closed. That is,
All tritium compounds in the air to be treated are converted into water by the oxidation catalyst bed 12 and adsorbed by the drying column 14 . The dew point meter 22 detects not only the breakthrough point of the drying column 14 in this adsorption process but also the decrease in adsorption capacity due to changes over time. When detected, the drying column 14 switches from the adsorption process to the regeneration process, and the drying column 20 enters the adsorption process.

That is, Vl, - circulation pump 11 - oxidation catalyst bed 12V2
, “3T”)! 513-Drying column 14-V4゜■7
-Dew point meter 16-Cooler 17-■8. ■11-Child heater 19
-Drying power ram 20-■□2. ■□3-Dew point meter 22-V□
The circulating air heated to 150-250C by preheater 1 is heated to 150-250C by heater 5.
the drying column 14 heated to
The drying column 14 is regenerated by desorbing the tritiated water adsorbed in the drying column 14. It is also possible to incorporate a tritium handling facility (2) into the closed circuit forming the regeneration process of this drying column 14. The air containing the tritium water desorbed in this way or the desorbed tritium water and the tritium water from the oxidation catalyst is cooled to 5C in the cooler 17 to condense and remove most of the tritium water. It is stored in the receiving tank 18. Cooler 17 as above
Most of the tritiated water is condensed and removed, but the tritiated water that is not condensed and removed is sent together with air to the drying column 20 at room temperature, where the tritiated water is adsorbed and completely removed. The breakthrough point of the drying column 20 under the above adsorption process is detected by the dew point meter 22.

Next, the air containing the tritium compound (air to be treated) that leaked from the tritium handling facility (■) is transferred to the tritium handling facility (I-V1) - circulation pump 11 - oxidation catalyst bed 12 - (2)
□. , ■11-Child heater 19-Drying column 20-V, □,
V13-Dew point meter 22-V, 4-) Circulate through the closed circuit of the lithium handling facility (■) to form an adsorption system. At this time, all other valves are closed. That is, all tritium compounds in the air to be treated are converted into water by the oxidation catalyst bed 12 and adsorbed by the drying column 20. The dew point meter 22 detects not only the breakthrough point of the drying column 20 in this adsorption process, but also the decrease in adsorption capacity due to changes over time. When detected, the drying column 2o switches from the adsorption process to the regeneration process, and at the same time, the drying column enters the adsorption process.

That is, Vl, - circulation pump 11 - oxidation catalyst bed 12'10
．． ■11-Preheater 19-Drying power ram 2O-V12°V
19-Dew point meter 16-Cooler 17-V6. V13-Preheater 1 filter-drying power ram 2O-V4. V5-Dew point meter 22-V□
A closed circuit of 5 is formed, and the preheater 16 is heated to 1.50~250C.
The circulating air heated to 150 to 250
The drying column 14 is regenerated by feeding it into the drying column 20 heated to C and desorbing the tritium water adsorbed in the drying column 20. It is also possible to incorporate the tritium handling facility (1) into the closed circuit forming the regeneration process of the drying column 14. The air containing the tritium water desorbed in this way or the desorbed tritium water and the tritium water from the oxidation catalyst is cooled to 5C in the cooler 17 to condense and remove most of the tritium water. It is stored in the receiving tank 18.

As mentioned above, most of the tritiated water is condensed and removed in the cooler 17, but the tritiated water that is not condensed and removed is sent together with air to the drying column 14 at room temperature, where the tritiated water is adsorbed and completely removed. will be removed. The breakthrough point of the drying column 14 under the above adsorption process is detected by the dew point meter 22.

A feature of the present invention is that the two drying columns are repeatedly adsorbed and regenerated by pulping operations, and there is no need to remove them for regeneration. Most of the tritiated water is condensed in a condenser, and the remaining tritiated water is adsorbed in another drying column and recovered in the next step. Therefore, in the present invention, there is no need to lower the temperature of the cooler to such a low temperature, and clogging of the cooler can be eliminated.

Examples of the present invention will be shown below.

Example 1 Tritiated water was removed using an apparatus as shown in FIG. Each drying column contains 5A” of molecular 7-
/16 inch throwlet 5.5 ky was filled. The oxidation catalyst was packed with 1.9 kg of Nigelhard A-'16648 1/8 inch pellets. Tritium water of 400-465 microcuries/ml was used as the tritium compound to be treated. The drying column is heated with 2
A cooler that can heat up to 50 tl' is a Freon refrigeration device that can cool down to an outlet temperature of 5C when the inlet air temperature is 40C. Tritiated water was adsorbed onto a dry column. Regeneration was performed at 260C for 5 hours. Air volume during playback: 5m3
It was 7 hours. 620ml of tritiated water was recovered from the cooler. 1.5X10-6 for drying column after regeneration
Tritium of microcuries/ml air was present, which was below the acceptable standard value.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing a conventional tritium compound removal device, and FIG. 2 is a flow sheet showing a tritium compound removal device of the present invention. Patent applicant: Japan Atomic Energy Research Institute (1 other person) (4 other people) Procedural amendment (method) February 73, 2013 Showa H year 1974 Patent Application No. 77-h, the case of the person making the amendment Relationship: Applicant Address: (UOQ) Japan Atomic Energy Research Institute (1 other person) 4 agents

Claims (1)

[Scope of Claims] 1. A tritium handling facility, an oxidation catalyst bed, and a tritiated water removal circuit are connected in series, and in the tritiated water removal circuit, a preheater-drying column A is provided. cooler and preheater-drying column B, are connected in parallel; (a) operating the pulp to form a circuit consisting of a tritium handling facility, an oxidation catalyst bed, and a preheater and drying column A; Air is circulated through the circulation circuit, tritium compounds generated from the tritium handling facility are introduced into the oxidation catalyst bed together with the circulating air, the tritium compounds are converted into tritiated water, and the tritiated water is mixed with the circulating air in the form of water vapor. The tritiated water is adsorbed into the preheater-drying column A, and the operation is continued until the adsorbent in the drying column A is at or near the breakthrough point; (b) then through at least the preheater-drying column A, the cooler and the preheater-drying column B, and through the tritium-handling facility (-manipulating the pulp so as to form a circuit or a circuit through the tritium-handling facility;
Meanwhile, air is circulated and drying column A is heated to desorb 1-1) tium water from the adsorbent in drying column A, and most of the tritium water is condensed in the cooler, and the remaining tritium water is dried. It is adsorbed onto column B, thereby regenerating the dry column A, (,?) l-! J Pulp is operated to form a circulation circuit consisting of a tium handling facility, an oxidation catalyst bed, a preheater and a drying column B, and air is circulated through the circulation circuit to remove tritium compounds generated from the tritium handling facility. The lithium water is introduced into the preheater-drying column B in the form of steam together with the circulating air to convert the l-IJ tium compound into tritiated water. adsorb onto the drying column and continue the operation until the adsorbent in drying column B is at or near the breakthrough point, and (d) then at least the preheater-drying column B, the cooler and the preheater-drying. The valves are operated to form a circuit through column A and either bypassing the tritium handling facility or through the tritium handling facility, circulating air between them to heat drying column B and drying column A. Repeating the process consisting of desorbing tritiated water from the adsorbent, condensing most of the tritiated water in a cooler, and adsorbing the remaining tritiated water onto drying column A, thereby regenerating drying column B. A continuous tritium removal method consisting of: 2. A tritium handling facility, an oxidation catalyst bed, and a tritium water removal circuit are connected in series, and the oxidation catalyst bed plays the role of converting tritium compounds into tritium water, and the tritium water removal circuit has a preheater and a drying column. , a cooler and a preheater and a drying column are connected in parallel, a tritium water receiver is connected to the cooler, and a tritium handling facility, an oxidation catalyst bed, and any one of the two preheaters and drying columns are connected in parallel. A circulating circuit that passes through the preheater and drying column on one side, a cooler, and the preheater and drying column on the other side and does not pass through the tritium handling facility, or a circulation circuit that passes through the tritium handling facility can be formed. Continuous tritium removal equipment with valves installed.