Abstract
Meticulous planning is essential for debris removal from the damaged reactors at the Fukushima Daiichi Nuclear Power Station to avoid dispersing radioactive material into the environment. The debris retrieval requires a prior phase of cutting to extract debris pieces after pieces before further processing and long-term storage. Several cutting methods are considered due to the high heterogeneity of fuel debris, as well as the varying operating conditions on the different locations. Both mechanical cutting and laser cutting are contemplated to achieve this goal. These two techniques have been proven to generate dust, in the present case, from a highly radioactive material, that will disperse in the containment vessel and might deposit on the remaining structures and walls. The integrity of the containment vessels cannot be proven, and it is essential to ensure that the particles would remain inside the vessel and would be captured efficiently by the counter-measure methods.
To be able to predict the local aerosol concentration evolution, it is aimed to develop a transfer function that takes into consideration key input parameters, defined by the cutting method and by the atmospheric conditions, in addition to other continuous phenomena that will affect the physical properties of the aerosol and consequently the local concentration.
This present work is devoted to the preliminary study of the agglomeration dynamic of a simulant dust and its potential deposition on stainless steel surfaces.
Dust agglomeration is occurring substantially in a matter of tens of minutes or hours and should quantified within the scope of transfer function development, as it will affect the particle’s dynamics and the efficiency of mitigations measures.
Regarding dust deposition, the preliminary observations show that clean and dry stainless steel does not promote particle deposition.
