DISCOLORATION OF THE WETTED SURFACE IN THE 6.1D DISSOLVER

[摘要] During a camera inspection of a failed coil in the 6.1D dissolver, an orange discoloration was observed on a portion of the dissolver wall and coils. At the request of H-Canyon Engineering, the inspection video of the dissolver was reviewed by SRNL to assess if the observed condition (a non-uniform, orange-colored substance on internal surfaces) was a result of corrosion. Although the dissolver vessel and coil corrode during dissolution operations, the high acid conditions are not consistent with the formation of ferrous oxides (i.e., orange/rust-colored corrosion products). In a subsequent investigation, SRNL performed dissolution experiments to determine if residues from the nylon bags used for Pu containment could have generated the orange discoloration following dissolution. When small pieces of a nylon bag were placed in boiling 8 M nitric acid solutions containing other components representative of the H-Canyon process, complete dissolution occurred almost immediately. No residues were obtained even when a nylon mass to volume ratio greater than 100 times the 6.1D dissolver value was used. Degradation products from the dissolution of nylon bags are not responsible for the discoloration observed in the dissolver.

[发布日期] 2013-12-18 [发布机构] Savannah River Site (S.C.)

[关键词] 42 Engineering H-Canyon, Dissolver, Discoloration, Corrosion;H-Canyon, Dissolver, Discoloration, Corrosion;12 Management Of Radioactive And Non-Radioactive Wastes From Nuclear Facilities