Patent Number: 039473210
Section: summary

This invention relates to neutronic reactors, and particularly to a control and shim rod shield room for a reactor. As is more fully described in the copending application of Robert M. Evans Ser. No. 649,407 filed Feb. 21, 1946, in which is disclosed a neutronic reactor with which the present invention finds particular adaptation, it is necessary for control of the operation of the reactor to provide control and shim rods of neutron absorbing material which can be inserted into the reactor preferably from one lateral face, and withdrawn therefrom partially or fully as dictated by the activity of the reactor. For this purpose, suitable passages are provided in the reactor and control and shim rods are mounted for movement into and out of the passages. For further more detailed discussion of the nuclear physics and physical characteristics of neutronic reactors, particularly control and shim rods, reference is made to the copending application of Fermi and Szilard, Ser. No. 568,904, filed Dec. 19, 1944, now U.S. Pat. No. 2,708,656. However, the rods are highly radioactive when they are withdrawn from the passages due to the high degree of neutron bombardment to which they have been subjected while in the active portion of the reactor and a problem is presented of safeguarding personnel from the radiations from the withdrawn rods and from the open ends of the passages leading into the reactor. One of the principal objects of the present invention is to provide novel simple and effective means of shielding control and shim rods when they are in their withdrawn position. Another object is to shield personnel from radiations from the control and shim rod passages into a reactor when the rods are fully removed for servicing or repairs.