Development of a remote laboratory-scale waste treatment facility

A waste treatment facility, designed on the basis of a feedrate of 1 l/hr of concentrated waste to a spray calciner, has been installed in a radiochemical hot cell at Pacific Northwest Laboratory. The facility includes three modules: feed preparation (storage tanks, evaporator, condenser), waste solidification (a spray calciner and in-can melter), and effluent control (venturi scrubber, cyclone separator, fission product adsorbers, nitrogen oxides destructor, iodine adsorber, HEPA filter, and packed scrubber). The system is flexible. The spray calciner and in-can melter can be easily removed and replaced by alternative solidification systems, and the effluent control system can be operated in many different sequences. Other components can be easily added to the effluent system for tests. Two effluent control flowsheets, designed to simulate those in defense waste and commercial waste processing plants, will be evaluated during the first radioactive runs. Most operational data from the system are remotely recorded continuously on strip-chart and multipoint recorders. Data on equipment operating parameters and upset conditions will be used to help maximize data on effluents, effluent decontamination factors and product quality. Five laboratory, pilot- and full-scale radioactive and nonradioactive waste solidification systems have already been operated at PNL. Experience with these systems demonstrated a need for additional radioactive work. Thus, the Remote Laboratory-Scale Waste Treatment Facility was developed. Operations completed with the other systems have indicated that scaling factors related to equipment size will not be a major consideration in the interpretation and usage of results from this equipment. These results can be used to provide guidance in developing full-scale radioactive waste treatment equipment