A Review of Dangerous Dust in Fusion Reactors: from Its Creation to Its Resuspension in Case of LOCA and LOVA

Abstract

Abstract:The choice of materials for the future nuclear fusion reactors is a crucial issue. In the fusion reactors, the combination of very high temperatures, high radiation levels, intense production of transmuting elements and high thermomechanical loads requires very high-performance materials. Erosion of PFCs (Plasma Facing Components) determines their lifetime and generates a source of impurities (i.e., in-vessel tritium and dust inventories), which cool down and dilute the plasma. The resuspension of dust could be a consequences of LOss of Coolant Accidents (LOCA) and LOss of Vacuum Accidents (LOVA) and it can be dangerous because of dust radioactivity, toxicity, and capable of causing an explosion. These characteristics can jeopardize the plant safety and pose a serious threat to the operators. The purpose of this work is to determine the experimental and numerical steeps to develop a numerical model to predict the dust resuspension consequences in case of accidents through a comparison between the experimental results taken from campaigns carried out with STARDUST-U and the numerical simulation developed with CFD codes. The authors in this work will analyze the candidate materials for the future nuclear plants and the consequences of the resuspension of its dust in case of accidents through the experience with STARDUST-U.

3D Simulation of a Loss of Vacuum Accident (LOVA) in ITER (International Thermonuclear Experimental Reactor): Evaluation of Static Pressure, Mach Number, and Friction Velocity

“…The fluid dynamics of these events has been experimentally and numerically investigated inside the scaled experimental facilities. The authors carried out, in old works [18,27,[29][30][31], campaigns, where pressure, velocity, and temperature have been measured and analysed. Then, different numerical models have been developed to replicate properly LOVA events.…”

“…The mathematical model used in this work has been tested and validated with the experimental campaign in the scaled facility STARDUST-Upgrade [27]. At the moment, experimental data about LOVAs in TOKAMAKs do not exist, and then it is impossible to directly validate the model for these reactors.…”

“…From the point of view of security, this kind of accident is one of the main concerns about the continuous operation of a fusion reactor. Since the preliminary studies that led to the construction of ITER, many researchers have investigated the consequences of a LOVA or of a LOCA (Loss of Coolant Accident), making hypotheses about the quantity of dust contained in the reactor, the diameter of the breach, the pressurisation rate, and the dust resuspension percentage [27][28][29].…”

Development of a Device to Measure Mass and Resuspension Rate of Dust inside Confined Environments

“…In the laboratory of Quantum Electronics and Plasma Physics (QEP), University of Rome "Tor Vergata", the sensor system with the experiment STARDUST-Upgrade has been developed. It is a cylindrical stainless-steel vessel, where it is possible to replicate Loss of Vacuum Accidents with different conditions [17]- [24].…”

A novel integrated approach for the hazardous radioactive dust source terms estimation in future nuclear fusion power plants

“…Modeling of a fusion reactor vacuum vessel is crucial for accident analysis and to predict materials inventory and mobilization, both from the experimental and numerical point of view. For that reason, along with experimental facilities to reproduce source term mobilization phenomena [26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36] it is also very important to develop a numerical model [37, 38] in order to predict particles quantities, velocity and direction in case of accidents such as a loss of vacuum, and not referring just to administrative limits but to estimates based on a more accurate methodology.…”