RU2132095C1 - Device for carburizing liquid radioactive wastes - Google Patents

Abstract

FIELD: processing liquid radioactive wastes to transform them to carburized state. SUBSTANCE: device has tank with mixer connected at inlet to liquid waste delivery pipeline, cement batcher, and solid-admixture batchers which are interconnected with service cement bin and service solid-admixture bins, pipelines, and jet pumps; at outlet, tank with mixer is connected to inlet of vortex generator whose outlet is connected through circulating line with valve and pump to inlet of case with mixer and to drain; interconnected case with mixer, vortex generator, circulating line, and drain constitute mixing assembly and each of interconnected batchers, service bins, pipelines, and jet pumps form batch-metering feeder. EFFECT: improved capacity, reliability, and quality of final product. 1 dwg

Description

 The inventive device relates to the field of environmental protection, and more specifically to the field of processing of radioactive waste (RW) by fixing it in a stable solid environment. The most effectively claimed device can be implemented in cementing liquid radioactive (LRW), both homogeneous (leaks, solutions from regeneration, decontamination, LRW of nuclear power plants (NPPs) and radiochemical plants), and heterogeneous, containing spent filter materials (radioactive ion-exchange resins, filter - perlite, activated carbon) or mixtures thereof.

 A device for cementing radioactive waste [1], including a container for dry cement, a container for radioactive waste and reagents, a barrel with a load for mixing and a rotating device. The barrel with the load for mixing placed in it is filled with dry cement, radioactive waste and the closing aqueous phase (in the case of cementing solid radioactive waste), closed with a lid and rotated simultaneously in several planes. After reaching the required degree of homogenization of the mixture, the barrel together with the load for mixing and the resulting product is sent for disposal.

 The disadvantages of the known device are its reduced productivity, associated with the impossibility of 100% use of the useful volume of the barrel and the increased danger of the device due to the possibility of mechanical damage to the barrel with a mixing load.

 A device for cementing radioactive waste [2], including a container for dry cement, a container for radioactive waste and reagents, a container for sodium silicate, a screw feed mixer and a container for the finished product. The radioactive waste is mixed with the mixing aqueous phase (in the case of cementing solid radioactive waste) and, together with the dry cement, it is fed into a screw feed mixer, which homogenizes the mixture and transports it to a container where sodium silicate is supplied, which is intended to improve the quality of the finished product.

 A disadvantage of the known device is its reduced reliability associated with the danger of driving a screw feed mixer.

 The closest in technical essence to the claimed device is a device for cementing LRW [3], which includes a hopper for cement, a screw feeder - a cement dispenser, a mixing unit, which is a container with a screw mixer and a drain device, and a pipeline for feeding LRW into the mixing unit.

The known device operates as follows. LRW through the pipeline for supplying LRW is fed into the mixing unit. After mixing LRW using a screw feeder - cement dispenser, a predetermined amount of cement is fed from the cement hopper into the mixing unit. The supply of cement to the mixing unit is carried out with the mixer running. After filling the working volume of the mixing unit, the flow of cement is stopped. The mixture is stirred until complete homogenization, after which, when the mixer is working, the resulting radioactive cement mortar is discharged through a drain device, which is sent for long-term storage to a specialized storage facility, where it sets and forms a cement stone
The disadvantages of the known device are:
- reduced productivity of the device associated with the duration of a single cycle of homogenization of LRW and cement due to the low mixing capacity of the screw mixer;
- reduced reliability of the device, due to the fact that, due to its design features, the screw feeder - cement dispenser can, firstly: be clogged, and secondly: not provide a stable dosage of cement, as a result of which, for example, unauthorized an overdose of cement in the mixing unit and its quick setting in contact with LRW, and the result of the influence of both factors will stop the operation of the entire device;
- reduced quality of the final product (cement stone), associated with uneven properties in its volume due to the low mixing capacity of the screw mixer, especially if the LRW contains waste filter materials.

The advantages of the claimed device for cementing radioactive waste are:
- increase device performance;
- improving the reliability of the device;
- improving the quality of the final product.

 These advantages are provided due to the fact that the claimed device contains a container with a mixer, to the input of which a pipeline for supplying LRW is connected, as well as a cement dispenser and solid additive dispensers connected through a cement feed hopper and solid additive feed hoppers, pipelines and jet pumps with a hopper for cement and hoppers for solid additives, the outlet of the tank with a mixer is connected to the inlet of the vortex apparatus [4], which is connected via a circulation line to the valve and pump it is connected with the inlet of the container with a mixer and with a drain device, moreover, the containers connected to each other with the mixer, the vortex apparatus, the circulation line and the drain device together form a mixing unit, and each of the dispensers, feed bins, pipelines and jet pumps connected together is a feeder - dispenser.

The essence of the claimed device is illustrated in the drawing, which shows a General view of the device
A device for cementing liquid radioactive waste includes a pipeline for supplying LRW 1, a hopper for cement 2, a hopper for solid additives 3, jet pumps 4, pipelines 5, a supply hopper for cement 6, a supply hopper for solid additives 7, a cement dispenser 8, solid dosers additives 9, a container with a stirrer 10, a vortex apparatus 11, a circulation line 12, a valve 13, a pump 14, a drain device 15.

 The device operates as follows.

 First, with the help of jet pumps 4 from the cement bin 2 and bins for solid additives 3, cement and solid additives (radionuclide sorbents) are fed by pneumatic transport to the cement supply hopper 6 and solid additive bunkers 7. At the same time, LRW, with liquid additives introduced into them (cement plasticizers) through the pipeline for supplying LRW 1 with the mixer of the tank with the mixer 10 turned on, the vortex device 11 turned on, the valve 13 turned off, the pump 14 turned off and the closed drain device 15 is fed into the tank with the mixer 10 until it is full of the working volume of the mixing unit. After filling the working volume of the mixing unit, the LRW supply is stopped, the LRW pump is turned on, and the LRW is mixed using the mixer in the vessel with the mixer 10, using the vortex layer in the vortex device 11, and also by circulation using the circulation line 12. Into the mixed LRW using the cement dispenser 8 and the solid additive dispensers 9 enter the calculated amounts of cement and solid additives, then the cement dispenser 8 and the solid additive dispensers 9 are turned off, the resulting mixture is mixed until complete homogenization, the pump 14 is turned off, they dig the valve 13, open the drain device 15 and unload the finished product, close the drain device 15 and open the valve 13, after which the above described LRW cementing cycle is repeated as many times as necessary.

Tests have shown that:
- the performance of the claimed device due to the use of a new mixing unit exceeds the productivity of the device according to the prototype in 1.5 - 2 times;
- in the course of work for 20 days, there were no deviations from the set operating modes of feeders - dispensers;
- the presence of consumable bins ensures a uniform supply of cement and solid additives, which was confirmed by the constancy of the density of the resulting final product during all cycles of operation of the inventive device;
- in terms of quality, the final product obtained on the claimed device due to the use of the new mixing unit is higher than the final product obtained on the device according to the prototype, which was confirmed by the uniformity of its strength characteristics and water resistance throughout the volume (% of the variation in the values of similar characteristics in the volume of the final the product obtained on the device according to the prototype is on average in strength - about 50%, and in water resistance - 30%).

Sources of information
1. Nikiforov A. S., Kulichenko V.V., Zhikharev M.I. Neutralization of liquid radioactive waste. M .: Energoatomizdat, 1985, p. 132 - 133.

 2. Nikiforov A. S., Kulichenko V.V., Zhikharev M.I. Neutralization of liquid radioactive waste. M .: Energoatomizdat, 1985, p. 133 - 134.

 3. Sobolev I.A., Khomchik L.M. Disposal of liquid radioactive waste at centralized sites. M .: Energoatomizdat, 1983, p. 77 - 78.

 4. Logvinenko D. D., Shelyakov O. P. Intensification of technological processes in devices with a vortex layer. Kiev: Technics, 1976, p. 66 - 78.

Claims (1)

 A device for cementing liquid radioactive waste, including a mixing unit containing a container with a stirrer and a drain device, as well as a pipeline for supplying liquid radioactive waste connected to the inlet of the container with a mixer and through a cement feeder, cement hopper, characterized in that the device is additionally contains a hopper for solid additives connected to the inlet of the container with a mixer through feeders - batchers of solid additives, each of the feeders - cement batchers and solid additives consists of last well connected jet pump, pipeline, feed hopper and dispenser, and the jet pump connected to the hoppers for cement and solid additives, and dispensers to the inlet of the tank with a mixer, the mixing unit further comprises a vortex apparatus and a circulation line equipped with a pump, and the vortex apparatus has its own the inlet is connected to the outlet of the tank with a mixer, and the output is connected to a drain device and through the circulation line equipped with a pump to the inlet of the tank with a mixer.