| 摘要 |
968, 212. Controlling reactors. BABCOCK & WILCOX Ltd. April 4, 1961 [April 4,1960], No. 12086/61. Heading G6C. A reactor control member consists of a body 2 whose diameter increases from one end enclosed in a tube 1 of corresponding internal shape, the annular space between body and tube containing a neutron-absorbing fluid. Relative movement produced by screw 5 alters the cross-sectional area and hence the volume of this space; surplus fluid is contained in reservoir 7 outside the reactor core. Body 2 is hollow and its surface may be conical, paraboloid or of cosine form, or any convenient shape; a cosine form gives the annular space its greatest volume per unit length at an intermediate position, which can be made to coincide with the region of highest flux. Suitable fluids are BF 3 , B 2 H 6, B 2 0 3 , Kr enriched with Kr<SP>83</SP>, Xe enriched with Xe<SP>131</SP> , vapours of Cd or its compounds; materials may also be added which under irradiation form suitable fluids, e.g. Br, Se, Te. The tube and body are of graphite, Al 2 O 3 ,SiC, BeO, quartz, Zr, Al; ceramic materials may be lined with Cr, Mo., Ni, V. |
