JPH0740078B2 - Radionuclide removal equipment in degraded heavy water - Google Patents

Description

TECHNICAL FIELD The present invention relates to a radionuclide removing apparatus for deteriorating heavy water.

(Prior Art) In a nuclear power plant using heavy water as a coolant or moderator such as a new converter, an ion exchange resin is used to purify the heavy water. When using the ion exchange resin in a heavy water system, it is necessary to perform an operation of replacing light water in the product with heavy water, which is called deuteration before use, and an operation of replacing heavy water containing tritium with light water, which is called dewatering when discarded. Become.
Deteriorated heavy water, which is a mixture of heavy water and light water, is generated during the operation at the time of disposal, and in addition to tritium, radioactive nuclides adsorbed during purification are mixed in this deteriorated heavy water. Deteriorated heavy water is concentrated to about 99.8% and collected by an isotope concentrator called an upgrader.

The conventional pretreatment system for the upgrader is Co-60 in deteriorated heavy water.
Ion is removed, and further, solid Co-60 is removed by a filter. Since the ion exchange resin used in this apparatus cannot be discarded while containing heavy water, it is necessary to carry out a lightening operation, and at this time, the amount of deteriorated heavy water 2-3 times that of the ion exchange resin is generated.

Further, since the used ion exchange resin is usually transferred by water, waste water containing 5 to 6 times the amount of radionuclide is produced.

Further, it is usually difficult to incinerate the waste ion exchange resin in an incinerator of miscellaneous solids, and it is stored in a storage tank. The filter is stored as a crude solid after the drying process. That is, in the conventional method using the ion exchange resin, there is a problem that a large amount of radioactive waste water is generated in the used ion exchange resin and before and after the treatment.

(Problems to be solved by the invention) The present invention aims to make a device for removing radionuclides such as Co-60 in deteriorated heavy water compact for the purpose of preventing dose accumulation in the upgrader, and to make it easy to handle. To do.

(Means for Solving the Problems According to the Invention) In removing Co-60 metallic radionuclide in deteriorated heavy water, a circuit for removing ions and solid matter in the deteriorated heavy water through a cartridge filter filled with activated carbon impregnated with oxine, and And a drying circuit having a dehumidifier and a heater for drying the activated carbon containing heavy water in the cartridge filter in the circuit.

(Example) It demonstrates based on a figure. Deteriorated heavy water 1 is passed from a pipe a to a cartridge filter 2 of powdered oxine-impregnated activated carbon to remove Co-60 radionuclides, and is transferred to an upgrader 3 by a pipe b.

The powder oxine impregnated activated carbon cartridge filter 2 was filed by the present applicant at the same time as the present application. As shown in FIG. 2 or FIG. Cartridge 11 with particle size distribution adjusted to 50-200 mesh with 12 powdered oxine charcoal
Filled inside or between 11a and 11b.
A prefilter 13 of about 0 μm is placed at the outlet of the processing liquid for several μm.
The post filters 14a and 14b are attached.

After the use of the oxine impregnated carbon cartridge filter 2, the valve is opened and the heavy water in the cartridge filter 2 is drained to the deteriorated heavy water recovery tank 4 via the pipe c.

After that, the compressor 10 is started, and the air dried by the dehumidifier (for example, the molecular sieve filling device) 5 is heated by the heater 6.
It heats up and it sends air to the cartridge filter 2 through the piping d and e system, and the heavy moisture of the oxine impregnated activated carbon is moved to the air side. The heavy moisture in the air is adsorbed by the dehumidifier 5 and is again sent to the cartridge filter 2 as dry air.

Next, the heavy water adsorbed by the dehumidifier 5 is regenerated by utilizing the pressure difference or the temperature difference. The regenerated gas containing heavy water is sent to the condenser 7 through the pipe f, cooled there, and collected in the deteriorated heavy water tank 4 as deteriorated heavy water. Reference numeral 8 is a blinch ring unit. By preparing the two dehumidifiers 5 and using them alternately, the oxine charcoal cartridge filter 2 can be dried continuously. Since these dehumidifiers 5 are known ones, their details are omitted.

When the drying with the dry air is completed, the oxine charcoal cartridge filter 2 is removed and all or most of it is replaced. All or most of the removed oxine charcoal cartridge filter 2 is incinerated to reduce the volume.

The deteriorated heavy water collected in the deteriorated heavy water recovery tank 4 is pump 9
After that, water is again passed through the oxine charcoal cartridge filter 2 and then transferred to the upgrader.

As explained above, the ions and solids (clad) of metallic radionuclides such as Co-60 in the deteriorated heavy water are removed by the oxine charcoal cartridge filter 2, then the radionuclide is adsorbed, and the oxine containing heavy water The charcoal cartridge filter was dried, and after the drying was completed, the cartridge filter was removed, and all or most of it was incinerated for volume reduction.

(Effects) 1) Conventionally, ions and solids of metallic nuclides such as Co-60 were treated by separate devices with each function, but this was treated by one oxine charcoal cartridge filter with both functions. Since this is possible, the device can be simplified.

2) By drying the oxine charcoal cartridge filter, it is possible to prevent the generation of a large amount of deteriorated heavy water at a lower concentration.

3) The amount of waste can be reduced by incineration and volume reduction after drying.

4) It is possible to eliminate the generation of waste water containing a radionuclide, which has been conventionally caused by the transfer of the used adsorbent.

[Brief description of drawings]

FIG. 1 shows the device of the present invention. 2 and 3 show two examples of cartridge filters. In the figure; 1 ... Deteriorated heavy water 2 ... Cartridge filter 3 ... Upgrader 4 ... Deteriorated heavy water recovery tank 5 ... Dehumidifier, 6 ... Heater 7 ... Condenser 8 ... Blinch ring unit 9 ...... Pump, 10 ...... Compressor 11 …… Cartridge, 12 …… Powdered oxine charcoal 13 …… Pre-filter 14a, 14b …… Post-filter 15 …… (stock solution) inlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikiya Fujii 2-1-1 Yado-cho, Tanashi-shi, Tokyo Metropolitan area Sumitomo Heavy Industries, Ltd. Tanashi Factory (56) Reference JP-A-57-162642 (JP, A)

Claims (1)

[Claims] 1. A device for removing metallic radionuclides such as Co-60 in deteriorated heavy water, which removes ions and solids in deteriorated heavy water through a cartridge filter filled with activated carbon impregnated with oxine, and the circuit. A drying circuit equipped with a dehumidifier and a heater for drying the activated carbon containing heavy water in the cartridge filter therein.