The MDS Nordion gamma irradiator is housed in FASB. It is a self-contained, cobalt-60 gamma ray source. Its primary uses are gamma irradiation effects on reprocessing solvents, reliability testing of materials and components prior to introduction into a hot cell and radiochemical separations.
A test loop system has been designed and installed at INL to evaluate the effects of gamma radiolysis and acid hydrolysis on the stability and performance of solvent extraction process solvents. Since all preferred solvent extraction processes must exhibit high radiolytic and hydrolytic stability, this test loop will not be limited to any one solvent system but will be applicable to all systems of interest. The effects of radiolysis/hydrolysis on a particular solvent extraction flowsheet or solvent component are evaluated by recirculating an aqueous/organic dispersion through the solvent irradiation loop until a desired absorbed gamma dose is achieved and then passing the irradiated organic solvent through the applicable scrub, strip, wash, etc., stages of the flowsheet.
The conditioned organic solvent is then dispersed with a fresh aqueous solution and subjected to another cycle in the solvent irradiation loop. The irradiation source is a MDS Nordion GammaCell 220 Excel self-contained 60Co gamma irradiator. The gamma dose rate is approximately 3.5 kGy/hr in the center of the sample chamber. The solvent irradiation loop is based upon a coil of borosilicate glass tubing (0.375" OD, 0.202" ID) which is placed in the gamma irradiator sample chamber. The current effective dose rate for the radiolysis test loop is ~2.5 kGy/hr.