Complete extraction of radio nuclides in the form of fine powder from liquid radioactive waste (LRW), produced in the operation of nuclear reactor installations: EcoAtom Company successfully installed and tested an industrial-scale prototype plant at Armenia's Metzamor Nuclear Power Plant (NPP), which processes the liquid radioactive waste at a rate of 1tonne/hour, outputting only industrial-grade clean water.
EQUIPMENT DESCRIPTION
LRW Treatment Equipment
The equipment is designed
• to reduce the volume of LRW
• to separate the boracic acid from LRW
• to provide selective separation of radioactive isotopes, specifically radioactive isotopes of Cs and Co
The treatment system is based on the method of electrodialysis. Particularly, the new method allows unique selective separation of radioactive isotopes based on the differences of several parameters (electrochemical potential, factor of diffusion, ion sizes, etc.). The main parts of the equipment include filters, electrodialyzers, tanks and ion-exchangers. There are three types of filters: mechanical filter, oil filter, ultra filter. The radioactive isotopes are separated by the system, which contains six modified electrodialyzers.
The above technologies are extended to also clean industrial wastewater and remove heavy and toxic metals from contaminated grounds.
Operational Units and Activities
The main part of the equipment is installed in the hall. It allows to perform the following operations:
• final collection of LRW
• filtration
• multi stages of electrodialysis
• collection of boron acid
• collection of the remaining waste
• collection and transfer of purified water
The final stage of electrodialysis and the collection of concentrated Cs and Co are carried out in hot camera. In the remote control centre are conducted the following:
• controlling the overall operation
• measuring concentration of separated compounds
• measuring the electrochemical parameters
• measuring the level of radioactivity at each operational unit
• controlling radiation dosage
Steps of Operation
The processing of LRW by LRWTE includes the following sequential steps:
• Removal of mechanical particles through the mechanical filter
• Removal of oil particles through the oil filter
• Removal of disperse particles through the ultra filter
• Ion exchanging process through membranes
• Ion separation process through electrodialyzer
• Concentrating of separated isotopes through the elecrodialyzer-concentrator
• Processing of the resulted mass through the new special electrodialyzer-concentrator
• Separation of certain isotopes as solid homogeneous chemical compounds.
Technical Characteristics of LRWTE
Thedesigned by us LRWTE which is installed in Armenian NPP, has the following characteristics:
• Weight is 10 tones
• Installation area is 100 sq. m
• Content of Salt in Initial LRW must be less than 5g/l
• Capacity of the equipment is 1ton/h
• Electric Power consumed is 25 kw
• Separation of Cs and Co Isotopes is up to 99.9%
• Degree of Radioactivity in Purified Water is less than Ci/l, which means that purified water meets the sanitary standards ( Ci/l)
Comparison of methods
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Decontamination solutions may content different radionuclides and metals salts.
The Mobile System is designed
• to reduce the volume of LRW
• to provide separation of radioactive isotopes, specifically radioactive isotopes of Cs, Co and Sr.
The following figure shows main component blocks mounted on a standard 12.2 m (40ft) long trailer.
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1 – LRW input tank |
2 – Coarse mechanical filtration unit |
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3 – Fine mechanical filtration unit |
4 – Processor for solution dilution |
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5 – Oil filtration unit |
6 – Electrodialysis separator into base & acid sol. |
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7 – Radioactivity confining shielded hot area |
8 – Electrolysis extractor-concentrator module |
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9 – Vault of extracted metallic radionuclides |
10 – Base solution recirculation tank |
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11 – Acid solution recirculation tank |
12 – Mobile facility’s LRW processing area |
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13 – Output cleaned water holding tank |
14 – Mobile facility’s equipment control area |
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15 – Computerized control panel & monitors |
16 – AC-to-DC converter-transformer & monitors |
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17 – Mobile Facility’s operator station |
18 – Observation window & separation door |
(*) Fluid piping connections, pumps, valves, electrical connections, heaters & coolers are not shown