Table 1 ['] lists the ratio of the nuclear energy of the commonly seen absorbant elements. The absorption cross section is higher than that of b. Only the invagination, SM, Eu. Many elements in Table 1 are either very expensive, or have a short service life, or have too small cross-sectional plane products.To and do not often use. It's boron (including '" B1 9. 8%) of closed cross section in all natural elements arranged 5; in addition to the CD, S, m, outside the Eu, and also low in e d, calendar. E u long service life, large cross section, is a kind of promising material, but ten points expensive; dG in super heat energy spectrum range not absorption effect, with burn up too fast; dG is a commonly used thermal neutron absorber,However, under 2. 9 x 10 one plus J common oscillation peak, the cross section product is significant.Ren. Reading. One is shown in figure 1 a fly '" B and natural boron absorption area falls along with the change of neutron energy. Besides B, is almost all other elements (n, blade response, receive neutron absorption after release wear permeability strong radiation, increase the waste material handling difficult. Although' "B (n, a) 7 iL excitation response, u also released in nuclear decay is 0. 7, 65 x 10 a '3 J ray,However, this is relatively soft compared with the 7 rays emitted by most medium weight atoms or heavy atoms. In nuclear industry practice, only boron containing materials (C, boron steel, C, etc.), Ag playing a Cd, E absorbing Q, fH and a few other types are most commonly used. The absorption cross-section area of 10 B varies with the neutron energy.