Engineering Model of Beryllium Dust Layer Oxidation in an Accident with Coolant Outflow from the Cooling System into the ITER Vacuum Chamber

Steam oxidation of beryllium dust, which will inevitably be formed and accumulated in the vacuum chamber of the ITER thermonuclear reactor, can occur in emergency situations associated with the water flow from the cooling system of the first wall or divertor into the vacuum chamber (LOCA-type accident). This process is accompanied by the release of free hydrogen, which creates a risk of fire or explosion when mixing with air. The safety analysis of a thermonuclear reactor should include numerical estimates of the degree of oxidation and the amount of hydrogen released. The paper presents an engineering model that allows, with a given steam content in the volume of the chamber, to determine the rate of hydrogen production during the oxidation of beryllium dust layers and the total amount of hydrogen formed during an accident. An analytical assessment of the oxidation rate of the dust layer is carried out.