Design And Preparation Of Flexible Neutron Shielding Material

With the growing global energy crisis,The research and application of new energy has become one of the strategic objectives of the sustainable development of the major countries in the 21 st century.The development and application of nuclear energy technology has become the core of new energy development.The application of nuclear science and technology has deepened into the fields of ship,submarine,aviation,aerospace,medicine,agriculture and other national security and national economy and people’s livelihood,and become an indispensable part of modern society.Various types of high-energy radiation（such as X-rays,gamma rays,and neutron rays）produced by radiation from nuclear materials not only impose higher requirements on the radiation-resistant materials of the relevant materials in the reactor,and the failure to form a leak may cause significant environmental Pollution（nuclear pollution）,serious harm to human life and health.Therefore,the reasonable control and protection of nuclear radiation has become a major problem in the development of nuclear power.Especially in China’s nuclear power to accelerate the development of today,to seek a new nuclear radiation protection materials,especially with the energy,penetrating ability and other characteristics of neutron protective material,is a new type of nuclear power design and construction of one of the key materials.The neutron shield is fabricated from neutron-moderator materials and neutron-absorber materials.Traditional neutron-moderator material contains cement-based material,metal-based material,fibre resin,polyethylene and so on.As a kind of synthetic silica gel,the special structure of silicone rubber makes it possess good heat resistance,corrosion resistance and radiation resistance.The thermal cross section of boron is 3837 b,and because boron captures low r-ray radiation energy,it is very suitable for thermal absorption.In this paper,a series of composite neutron shield material of boron phenyl siloxane rubber were prepared by using phenyl siloxane rubber as neutron-moderator material,boron containing compounds as neutron-absorbing material,and its performance was studied.First,different phenyl content silicone rubber was synthesized by steps of anion ring-opening,hydrolysis,polymerization,and the molecular structure and heat resistant properties were studied.The study shows that as-prepared silicone rubber contains phenyl,and the phenyl contents are consistent with expectation.The heat resistant property increased with the increase of phenyl contents.The decomposition temperature of as-prepared phenyl siloxane rubber is between 350-400℃,which meets the requirement temperature of nuclear test site.Then phenyl silicone rubber and boron compounds were mixed equality by using kneading and hot vulcanization process to prepare a series of composite neutron shield material of boron phenyl siloxane rubber.This paper examined the B₄ C content,thickness of composite material,nanomaterial,phenyl content,type of functional material these five factors on properties of neutron field material.The results prove that B content of B₄ C phenyl silicone rubber should be 20%³0%;the appropriate thickness of composite neutron field material is 3⁵mm;nanomaterials can upgrade comprehensive properties of composite materials;neutron shielding properties and heat resistant properties increased with the increase of phenyl contents;compared to B₄ C composite material,BN composite material has lower flexibility.Finally,composite neutron field material was prepared by grafting modification of B₄ C,the result shows that mechanical properties and neutron fielding properties were increased after grafting modification of B₄ C.