Separation of iodine produced from fission with a porous metal silver column in99Mo production

Abstract

In Argentina, at the Ezeiza Atomic Center, 13~I is produced by wet distillation of naturat tellurium dioxide irradiated with thermal neutrons in a pool-type reactor. In order to recover the 13~1 present in the production process of fission 99Mo obtained by irradiation of UAIJAI targets (with 90% enriched uranium) a separation method was developed, lodine isotopes can be separated from a sodium hydroxide solution containing fission products using a column filled with alternate beds of glass microspheres and porous metal silver. Tests with tracers were performed in radiochemical laboratory. Following this results, a series of tests with higher activities (3 TBq of 99Mo and 0.7 TBq of 131I) were carried out in hot cellsl Molybdenum passes through the silver column, while 131I retention was 92-97% in tracer test and 90% in optimised hot cell tests. This result depends on several facts that are discussed. An initial separation of iodine isotopes diminishes radiation damage on ion-exchange resin used in the subsequent molybdenum purification, improving its retention and elution yield.

27 Radiochemistry

“…The isotope 125 Sb can be separated 29 from neutron irradiated tin using a silica gel column whilst 131 I can be removed 30 from ¢ssion products (as a stage in the puri-¢cation of 99 Mo) using porous silver. A simple generator for 188 Re (from the decay of 188 W) has been described 31 in which saline elution yields a solution of sodium perrhenate.…”

Sorption and desorption studies of radioiodine onto silver chloride via batch equilibration with its aqueous media

“…A chromatographic column of porous silver could be used for retention of 97% of fission 131 I from alkaline solution during the production process of fission 99 Mo (Mondino et al, 1999). Freshly precipitated silver iodide could be used to sorb 70% of the residual trace 131 I impurity from fission 99 Mo in ammonia solution (Deptuła et al, 1974).…”

Estudo de rotas de purificação em processos de produção de Mo-99 e I-131 de fissão

“…Neste exemplo de destilação seca de óxido de urânio, o alvo irradiado foi aquecido a 800 ºC, sob fluxo de ar, e os vapores de iodo foram coletados em solução de NaOH e bissulfito de sódio (ABRASHKIN e RADICELLA, 1964 MONDINO et al, 1999;WILKINSON et al, 2003). Em outro caso o iodo radioativo foi adsorvido em uma pequena coluna contendo platina particulada e com um fluxo alternado de hidrogênio e solvente, obtendo-se assim a dessorção do iodo (BRAKE et al, 2002…”

“…A retenção do I-131 em colunas cromatográficas contendo prata (óxido/metálica) ou carvão tem sido empregada nas linhas de processamento de Mo-99 como etapa inicial de separação, podendo ser processado paralelamente, por meio de técnicas complementares como destilação úmida e precipitação (MONDINO et al, 1999;EL-ABSY et al, 2010;SALACZ, 1985).…”