It is required to secure decontamination technology that is easy to apply and minimizes the generation of secondary wastes for large-scale equipment and large-area decontamination, which are difficult to be applied structurally when massive repair or decommissioning of nuclear facilities. In this respect, decontamination foam has a potentially wide application in the removal of contaminants from metallic walls, overhead surfaces, and elements of complex components and facilities. The decontamination efficiency can be enhanced by improving the contact time between the chemical decontamination agents and the contaminated surface through the introduction of stabilizers into the decontamination foam.
In this study, the stability of a decontamination foam containing mesoporous silica nanoparticles as a stabilizer and the decontamination performance of radioactive isotope contaminated specimens were evaluated. A process for waste liquid treatment after foam decontamination was also proposed. Decontamination performance tests using RI contaminated specimens were carried out in a decontamination foam prepared only with a solution containing only 1 wt% EM100 surfactant and in a decontamination foam prepared with a solution containing 1 wt% EM100 surfactant and 1 wt% various silica nanoparticles. The stability of the decontamination foam was increased due to the addition of various types of silica nanoparticles. In particular, the liquid film thickness of the decontamination foam containing mesoporous silica nanoparticles was the largest. As a result, the decontamination coefficient for RI contaminated specimens increased as the thickness of the foam liquid film increased due to the longer contact time between RI contaminated specimen and the chemical decontamination agent as the thickness of the foam liquid film increased.