44 / 2024-06-06 13:48:52

EXPERIMENTAL PROGRESS OF 209BI(N,G)210GBI CROSS-SECTION MEASUREMENT BASED ON POLONIUM SELF-DEPOSITION TECHNIQUE

Lead-cooled fast reactor;Polonium;209Bi(n,γ)210gBi;Spontaneous deposition; Response Surface Methodology

Lead-bismuth-eutectic alloy (LBE:44.5 wt.%Pb+55.5 wt.%Bi) has become an important coolant candidate for the fourth-generation reactor due to its good physicochemical properties. However, the radiation protection risk of radioactive polonium caused by liquid lead-bismuth alloy as the main coolant of the reactor has become an important issue that must be paid attention to in the research and development of lead-bismuth reactors. The ²⁰⁹Bi(n,γ)^210gBi reaction is the key source term for the production of ²¹⁰Po in a lead-bismuth-led reactor. Accurate measurement of the ²⁰⁹Bi(n,γ)^210gBi reaction cross-section is very important for assessing the risk of radioactive polonium release from a lead-bismuth reactor. At present, the reaction cross section can be measured online by directly measuring the cascade of transient gamma rays of the capture reaction or offline by measuring the ^210gBi decay product ²¹⁰Po. In this work, the self-developed polonium self-deposition technology is used to design the technical scheme of ²⁰⁹Bi(n,γ)^210gBi cross-section high-precision measurement and the preliminary experimental verification work. The key elements of the experiment are optimized by the intelligent modified response surface analysis algorithm. The preliminary experimental results show that this technical route has strong feasibility, but there are also challenges in data analysis such as natural polonium background and polonium alpha decay spectrum interference. Artificial intelligence technology has become an important research idea to solve related problems.