Effect of Gadolinium and Depleted Uranium on the Nitric Acid Dissolution of Samples from the 242-16H Evaporator Pot

Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent inspection of the evaporator showed significant formation of solids in secondary lines and in the evaporator pot. Tests completed at Savannah River Technology Center (SRTC) showed dilute nitric acid will dissolve the solids. Because the solids contain significant quantities of 235U, operations may need to add neutron absorbers such as gadolinium and depleted uranium to the nitric acid to avoid any potentiality for a nuclear criticality. Therefore, the authors performed a series of tests to ascertain the effect of these neutron absorbers on the dissolution of the sodium aluminosilicate