Metals etc. in the research and application of boron carbide/aluminum neutron absorbing materials

Dragon Boat - Boron Nitride Absorption Plate and Container Prototype for CNSC Spent Fuel Tanks

Dragon Boat - Acceptance Meeting for prototype of CNSC spent fuel transport container

The neutron absorbing material, also known as neutron poison material, absorbs thermal neutrons by containing large neutron absorption cross-section substances (such as boron, cadmium, tellurium, etc.), thereby suppressing nuclear fission chain reaction, and is mainly used for nuclear fuel and depletion. In the storage and transportation of fuel, the subcritical safety of storage and transportation is ensured. The boron carbide-reinforced aluminum (B4C/Al) neutron absorbing material is a new type of aluminum-based composite material formed by adding B4C particles into an aluminum matrix. Due to its advantages of high boron content, low density, high thermal conductivity, etc., Abroad, traditional neutron absorbing materials such as boron stainless steel have been widely used in the high density storage and transportation of nuclear fuel/spent fuel. Due to the late commercialization of nuclear power in China, research and development of neutron absorbing materials lags behind. B4C/Al neutron absorbing materials rely on imports for a long time, which seriously restricts China's nuclear power autonomy and development strategy of going global.

In recent years, the research group headed by Ma Zongyi, a researcher at the Institute of Metal Research, Chinese Academy of Sciences, worked with China Nuclear Power Engineering Co., Ltd. to carry out research on B4C/Al neutron absorbing material preparation, simulation of environmental service performance assessment, and development of full-size engineering parts. . Overcoming the problems of interfacial control during the preparation of large-size billets, breaking the bottleneck of high-productivity, high-yield-rate roll forming of high-content B4C/Al sheets, developing welding tools and welding processes suitable for welding composite materials, and opening up materials from materials. The development of a full-chain technology approach to device formation has laid a solid foundation for the engineering application of this material. A series of neutron absorbing plates with B4C content of 15~35wt% have been developed and the experimental evaluation of accelerated corrosion, high temperature aging, accelerated irradiation and boron uniformity test (neutron absorption method) has been completed, and the performance of the materials has been fully achieved. (such as corrosion resistance, etc.) is obviously better than similar foreign products.

Since 2014, Metals has successively provided prototypes for nuclear power special projects “Technical Projects for Design and Manufacturing of Nuclear Fuel Component Transport Containers” and “High Temperature Gas-Cooled Reactor Nuclear Fuel Element Transport, Storage Vessel Design and Manufacturing Technologies and Transport Process Technology Research Projects”. A number of batches of B4C/Al sheets were used to first realize the local supply of B4C/Al neutron absorbers. The neutron absorption plate supplied in May 2014 was used as a prototype for the National Science and Technology Major Project and CNNC's special scientific and technological project “Dragon Boat-CNSC Spent Fuel Transport Container Development” project. The prototype was recently approved by Xi’an Nuclear Equipment Co., Ltd. This indicates that China has independently developed a large-scale spent fuel transport container, filling the domestic gap, which has a milestone significance for China's spent fuel transportation. As a key component in the localization of key materials for spent fuel transportation containers, the B4C/Al neutron absorbing material developed by the metal has provided important support for the overall localization of containers and laid a foundation for the wider application of this material.

At the same time, for the first time in the world, the need for a neutron-absorbing material cylindrical structure for transporting and storing containers of new high-temperature gas-cooled reactors for high-temperature gas-cooled reactors has been achieved. Coiled operation and friction stir welding of neutron-absorbing materials have been realized for the first time in China. Sub-absorbent material breaks from a plate-like structure to a cylindrical structure. At present, Huaneng Shandong Shidao Bay Nuclear Power Plant High-Temperature Gas-Cooled Reactor Nuclear Power Plant Demonstration Project The new fuel element transport and storage containers have officially entered the mass production phase, and Metals has undertaken the task of supplying all neutron absorption plates for the vessel.

At present, the task force is working on the development of B4C/Al neutron absorbers that are structurally functional and integrated for the next generation of spent fuel dry storage vessels. The research work was supported by the NSFC-Lianning Joint Fund, the Fund, and the Youth Innovation Promotion Project of the Chinese Academy of Sciences.