RPV Irradiation Embrittlement Key Technology Research Based On Barkhausen Noise

With the rapid development of nuclear industry both at home and abroad, it faces huge challenges and opportunities. Nuclear reactor pressure vessel, long-term working under high temperature and high pressure, causes its irradiation embrittlement. Based on this situation, this paper plans to develop a set of Barkhausen noise detection system to detect irradiation embrittlement effect on material property. The experiment takes RPV steel A508-3 as basic material for proton irradiation to research matrix damage during irradiation. And it takes Fe-1.0wt.% copper alloy, the simulation steel, as basic material for heat treatment to research Cu rich clusters precipitation during irradiation. This research method is effective in avoiding the shortcomings of strong neutron irradiation study, like long research cycle and being harmful to human body. And the usage of two kinds of materials avoids cross impact of matrix damage and Cu rich clusters precipitation. As a result, their separate effect on material property is clear.After reading a large number of literature, based on electromagnetism knowledge, mechanism research of MBN is done. From the Angle of magnetic domain structure and magnetization theory, this paper detailedly analyzes the nature of Barkhausen noise and its detection principle, it also has a understanding of the influence factors of MBN. This paper researches irradiation embrittlement mechanism and the influence factors and studies the leading microcosmic factors of irradiation embrittlement at different stages. It lays foundation for later sample processing.Based on the existing hardware platform, this paper optimizes sensor and signal processing part, obtains a smaller and more convenient hardware system. The software design contains three software platforms, Labview, Matlab and Access. The software system includes signal acquisition and display module, signal conditioning module, signal post-processing module and signal storage module. At last, a PC software applicable in RPV irradiation embrittlement is developed. Hardware combines software, making a whole Barkhausen noise detection system.Using the detection system, the experiment acquires MBN signal and knows four characteristic values, envelope area, envelope full height half width, envelope peak and RMS. Firstly, the paper does a verification experiment using ultra-low carbon steel containing Cu and Ni whose hardness is known. After verifying the feasibility, it carries on two materials detection, RPV steel with proton irradiation and Fe-1.0wt.% copper alloy with heat treatment, the simulation steel. According to the result, the paper analyzes matrix damage and Cu rich clusters precipitation effects on material property. It shows that both of them will cause MBN characteristic values change regularly. And the change tendency is consistent with the expected material hardening theory.