Method for solidifying boron-containing nuclear waste liquid by phosphate polymer

Abstract

The invention discloses a method for solidifying a low-level radioactive nuclear waste liquid by a polymer, and concretely relates to a method for solidifying a boron-containing nuclear waste liquid by a phosphate polymer. The method mainly includes the following steps: (1) mixing a concentrated phosphoric acid solution with a concentrated boron-containing nuclear waste liquid according to a certain ratio to prepare a mixed solution; (2) preparing a polymer precursor by using water glass and polyaluminum chloride as raw materials and hydrochloric acid as an additive; and (3) mixing the mixed solution obtained in step (1) with the polymer precursor obtained in step (2) according to a certain ratio, and performing uniform stirring to prepare a solidified boron-containing nuclear waste liquid. The method has the advantages of large capacity for the boron-containing nuclear waste liquid, no need of alkali addition for neutralization, overcoming of the defect of strong retardation of a cement solidification process, good stability of the final solidified body, simple preparation process, low cost, no secondary pollution, and easiness in engineer application.

Description

Technical field [0001] The invention relates to a method for solidifying boron-containing nuclear waste liquid with a phosphate polymer, and belongs to the field of solidification treatment technology and material for medium and low radioactive nuclear waste liquid. Background technique [0002] The global energy crisis has promoted the rapid development of nuclear energy utilization. With the rapid development of the nuclear energy industry, the issue of safe disposal of radioactive waste has become more prominent. The boron-containing nuclear waste liquid, as the radioactive nuclear waste liquid produced during the operation of the PWR nuclear power plant, is mainly composed of borate, a small amount of sodium nitrate and sodium phosphate. It has strong acidity, high salt content, and difficult treatment. At present, the main idea for nuclear power plants to dispose of boron-containing nuclear waste liquid is: nuclear waste liquid concentration-alkali neutralization-cement sol...

AI Technical Summary

Problems solved by technology

However, when the traditional cement solidification process solidifies boron-containing nuclear waste liquid, there are defects such as large alkali consumption, high cost, low inclusion capacity, strong borate retarding effect, and secondary pollution. It is urgent to develop a safe and efficient new type containing Solidification treatment process of boron nuclear waste liquid

[0004] Studies by scholars such as A.M. El-Kamash have shown that in the process of using cement to solidify radioactive waste, adding zeolite to ordinary Portland cement can effectively improve the compressive strength of the cement solidified body and reduce the leaching rate of nuclide ions. However, this method needs to add alkali to neutralize, the alkali consumption is large, and there are problems such as retardation

Chinese patent CN 101456715A discloses a curing method that reduces the leaching rate of radionuclides in the cement solidified body by adding zeolite and adds lime to adjust the setting time of the solidified body. Water reducer and other additives are added, and the cost is high

Chinese patent CN 105741899A discloses a new solidification treatment additive, solidification formula and process for radioactive boron-containing waste liquid. Sodium metaaluminate is used to accelerate cement hardening and coagulation, and borate is prepared into polymer borate and then curing agent is added. The solidification method can make the boric acid containment rate of the prepared solidified body reach 49.5%, which can better make up for the defects of low solidification containment rate and strong retarding effect of traditional cement

However, this technology still has disadvantages such as complex process, large alkali consumption, secondary pollution and high cost.

[0005] The above methods all use alkaline gelling materials to solidify boron-containing nuclear waste liquid, but none of them can overcome the defects of large alkali consumption, high cost, low containment capacity, strong borate retarding effect, and secondary pollution at the same time.