Study On Tritium Inventory In The Liquid Metal Lithium-Lead Blanket Module Of Fusion Reactors

Tritium is one of the two kinds of fuels used in fusion reactors, so research on its technology is one of the important issues for fusion. Even though it is hardly found on the earth, it can be produced from the reaction between lithium and neutron in the blanket of fusion reactors to make tritium self-sufficient. Because of its radioactivity and violent activity, tritium is very easy to permeate out of the blanket, and this will result in the losing of nuclear fuel and the potential radioactive hazard to workers and publics around fusion reactor. So it is very important to study on tritium inventory and distribution in fusion reactor, and the possible routes for it to get out of the reactor and auxiliary systems in order to take measures to reduce tritium permeation and to be sure of the safety of fusion reactors.The liquid metal Lithium-Lead blanket design is one of the important fusion reactor blanket design in the world, it's also the major scenario of fusion reactor design and the International Thermonuclear Experimental Reactor (ITER) Test Blanket Module (TBM) design in China, i.e. the Dual-Functional Lithium Lead Test Blanket Module (DFLL-TBM). In this dissertation, the preliminary study on tritium inventory for the liquid metal Lithium Lead Test Blanket Module, such as tritium permeation, tritium distribution and so on, were done.First, the property of tritium, the property of liquid Lithium-Lead eutectic, the principal of tritium multiplication and the method of tritium extraction from liquid metal LiPb were introduced, and then the principal of tritium diffusion and permeation, and the tritium permeation reduction method were discussed. The technologies to extract tritium from DFLL-TBM were discussed as well as by analyzing the configuration of the ITER DFLL-TBM and the auxiliary system. At the same time, a preliminary analysis on tritium permeation for the ITER DFLL-TBM systems and a permeation model for the entire TBM system were presented. Analysis on tritium inventory and permeation were done through calculating the tritium partial pressure in liquid LiPb based onsafety requirement. The factors which would affect the tritium permeation, such as the percentage of LiPb flow in tritium extraction system (F) and Tritium Permeation Reduction Factor (TPRF) etc., were discussed. The factors that would reduce tritium leaking into environment were mentioned as well. The preliminary study and sensitivity analysis on tritium inventory and system for DFLL-TBM were performed in order to be sure of the system safety from the point of view of tritium safety.