In order to obtain data for the development and design of the Purex dissolvers and to demonstrate to Manufacturing and Technical personnel the feasibility of increasing the size of dissolver cuts at BiPO{sub 4} and Redox, a dissolver production test program in a BiPO{sub 4} dissolver is requested. These tests are expected to supplement the program already initiated on the 321 Bldg. dissolver, explaining dissolver behavior to the extent that existing dissolvers can be operated under more nearly optimum conditions and that new dissolvers can be designed with accuracy.