Boric acid, white powdery crystal or trioblique axial surface scaly luster crystal, smooth feeling, no odor. Soluble in water, alcohol, glycerin, ether and essential oils, the aqueous solution is weakly acidic. A large number of glass (optical glass, acid-resistant glass, heat-resistant glass, glass fiber for insulating materials) industry, can improve the heat resistance, transparency of glass products, improve mechanical strength, shorten melting time.
　　
Moderation process
　　
U-235 produces fast neutrons after fission reaction, fast neutrons move in the moderator, the energy gradually decays, and finally becomes a thermal neutron, this time is called moderation time, this process is called moderation process, fast neutrons become hot neutrons after not necessarily immediately absorbed, but also move for a period of time, and finally absorbed, this time is called diffusion time. In the process of moderation, moderators can be used. The role of moderator is to moderate neutrons, so that neutrons are easy to react with the target nucleus, the prerequisite for doing moderators is to have a large scattering cross-section, small absorption cross-section, so that the moderation effect is good, the best moderator is heavy water, as well as carbon dioxide, carbon, water, boron-10 isotopes and so on.
　　
Boric acid absorbs neutrons
　　
Boric acid is a large neutron absorption cross-section, which is mainly used to adjust reactivity in reactors, and adding an appropriate amount of boric acid can reduce reactivity.
　　
Natural boron has two stable isotopes, ~(10)B and ~(11)B, with abundants of 19.78% and 80.22%, respectively. ~(10)B has the unique characteristics of high absorption of neutrons, ~ (10) B's absorption section for thermal neutrons is 3837 bar (1b=10, Pa), the absorption section of boron with natural abundance is close to 750 bar, while ~(11) is only 0.005 bar, so ~(10) B's absorption section for thermal neutrons is more than 5 times that of natural abundance boron, more than 20 times that of graphite, and more than 500 times that of traditional protective material concrete. That is, the boron-10 isotope is a highly effective thermal neutron absorber. Therefore, in nuclear power plants, it is indispensable in safety and control systems. Special grade (SQ) boric acid is used in the nuclear industry and has a high proportion of boron-10. Therefore, boric acid can terminate nuclear anti-application, absorb neutrons, and then fast-setting cement plugging, and then this place is no longer inhabited by no man's land for many kilometers.
　　
It is precisely because of this characteristic of ~(10)B isotope that ~(10)B isotope related products are widely used in military fields such as military protection, nuclear weapons and nuclear industry. Another function of boric acid is that it can be vitrified at high temperatures and can fix the diffusion of radioactive elements. (Just like glass fired in a glass factory)
　　
In addition, boron-10 isotopes can also be used in neutron counting tubes, used as protective screens in nuclear reactors, alignment rods, and also used to treat cancer.