N. I. Pavliuchenko, D. O. Muliar, A. O. Doroshenko
Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine,
36a, Kirova st., Chornobyl, 07270, Ukraine
Measures of dust suppression are considered, in particular, in the under-roof space of the Shelter object (SO). Methods for assessing the state of the protective polymer coating on the surfaces of the «collapse» of the 4th ChNPP unit and the intercontrophoric surfaces of the under-roofing space are described. The results of a mathematical and statistical analysis of monitoring the activity of radioactive emissions from the SO, the concentration of radioactive aerosols in the surface air layer at the industrial site of the SO are presented, as well as the dynamics of emissions of radioactive aerosols are analyzed. The evaluation of the protective properties of the area and depth of destruction of the coating was carried out and the thickness of the coating on the selected samples (in laboratory conditions) was determined.
According to the results of the research, conclusions were formulated, namely, the polymer coating firmly fixed radioactive dust on the coated surfaces, the growth over time of some of the monitored parameters is not associated with film destruction, there are minor secondary pollution processes, and the existing processes of coating destruction are slow. With the current operation of the Shelter object and without changes in its state, dust suppression measures are not recommended in the short term, as the coverage condition is satisfactory and it performs its protective functions, and the values of the monitored parameters do not exceed the operational limits.
Research contributes to optimizing the schedule of dust suppression sessions, their economic feasibility, because the amount of expensive localizing materials is reduced, the inflow and formation of radioactively polluted water to the New Safe Confinement (NSC) of the SO is reduced, which has a significant economic effect without environmental damage. In the future, it is necessary to continue monitoring the parameters of SO radioactive aerosols, and to assess the state of the protective coating in the sub-roofing and inter-control spaces of the NSC-SO.
The monitoring results should be used when taking decisions on the timing of irrigation with a protective coating, when detecting destruction processes, which result in an increase in the activity of SO radioactive aerosols.
Keywords: dust suppression measures, localizing of the polymeric coverage, standard of enterprise, estimation of the coverage state, radioactive aerosol.
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