Heat pump evaporation system and heat pump evaporation method used for processing low-activity liquid waste in nuclear plant

Abstract

The invention discloses a heat pump evaporation system and heat pump evaporation method used for processing low-activity liquid waste in a nuclear plant. The heat pump evaporation system comprises an evaporation tower bottom circulation loop, a steam cure pipeline and an evaporation tower heat exchanger; the steam cure pipeline is connected with the steam outlet of an evaporation tower, and is provided with a vapor compressor for pressurizing steam; the evaporation tower heat exchanger is connected between the steam cure pipeline and the evaporation tower bottom circulation loop; pressurized steam inside the steam cure pipeline is used for heating liquid waste in the evaporation tower bottom circulation loop. The heat pump evaporation method relates to a method using the system to treat the liquid waste. Compared with the prior art, the heat pump evaporation system and the heat pump evaporation method used for processing low-activity liquid waste in the nuclear plant can remarkably lower system consumption, and remarkably improve the separating efficiency of salt and radioactive nuclides, thereby having high economic benefit and use prospect.

Description

technical field [0001] The invention belongs to the field of nuclear power plant waste liquid treatment, and more specifically, the invention relates to a heat pump evaporation system and a heat pump evaporation method for treating nuclear power plant low-level waste liquid. Background technique [0002] Nuclear energy is a clean energy with great promotional value for quite a long period of time, but the three wastes treatment issues brought by nuclear power plants that affect environmental safety have become one of the restrictive factors affecting the widespread promotion of nuclear energy. For example, the waste liquid produced in nuclear power plants contains a small amount of radionuclides and different concentrations of salt, which is harmful to the human body and the environment. It needs to be treated before being discharged to meet the discharge requirements. [0003] At present, in the disclosed nuclear power plants, the evaporation process used for the treatment ...

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Problems solved by technology

However, there are at least the following problems in the evaporation treatment process of the above-mentioned low-level waste liquid: 1) the entire process consumes a large amount of high-temperature steam, and the cooling of the steam condensate consumes a large amount of cooling water, so the energy consumption is high and the economy is poor; 2) ) For the waste liquid with high salt content, the flow rate of the ordinary natural circulation evaporation process is low, which is easy to generate scaling in the system, which brings inconvenience to equipment cleaning and reduces the heat exchange efficiency of the heat exchanger; 3) The main equipment evaporation tower The separation performance is poor, and the boron content in the distillate distilled from the top of the tower is higher than the limit value of boron content in the discharged wastewater of the inland site, which reduces the environmental adaptability of the unit to the inland site

[0004] It can be seen that the high energy consumption and low decontamination efficiency of the above-mentioned evaporation treatment process have gradually failed to meet the requirements of energy conservation and emission standards, and it is necessary to provide a new waste liquid treatment process

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