Production of ³³P from ³⁶Cl and ³³S by Fast-Neutron Irradiation

Enriched ³³ S, prepared by electromagnetic separation techniques, and ³⁶ Cl, prepared by reactor irradiation of natural chlorine, were evaluated as targets for the production of ³³ P by the ³³ S(n,p)³³ P and ³⁶ Cl(n,α)³³ P reactions. The fission-neutron cross sections of these reactions and those of the ³² S(n,p)³² P and ³⁵ Cl(n,α)³² P reactions were measured in four positions in the Oak Ridge Research Reactor (ORR) at various distances from the fuel elements. Millicurie quantities of ³³ P were prepared by fast-neutron irradiation of enriched ³³ S and ³⁶ Cl and subsequent aging to deplete the ³² P content of the ³³ P. Chemical procedures for separation of carrier-free phosphorus activities from elemental sulfur and NaCl are given.