Removal of Pu-238 from aqueous process streams using a polymer filtration process

Abstract

LosAlamos NationalLaboratory an affirmativeaction/equalopportunityemployer,is operated bythe Universityof Californiaforthe U.S. Departmentof Energy under contractW-7405-ENG-S6. By acceptanceof thisarticle, the publisherrecognizesthatthe U.S. Government retainsa nonexclusive,royalty-freelicenseto publishor reproducethe publishedformofthiscontribution, or to allowotherato do ao,for U.S. Governmentpurposes.LosAlamos NationalLaboratoryrequeststhatthe pubiisheridentifythisarticle as work performedunderthe auspicesof the U.S. Departmentof Energy.LosAlamoa NationalLaboratorystronglysupportsacademicfreedom and a researched% rightto publish;as an institution, however,the Laboratorydoes notendorsethe viewpointof a publicationor guarantee itstechnicalcorrectness. Abstract. A glovebox facility is under construction at Los Alamos that will recover a significant quantity of the impure Pu-238 that exists in scrap and residues fkom past production operations. The general flowsheet consists of milling, acid dissolution, ion exchange, precipitation, calcinationj oxygen isotope exchange, and waste treatment operations. As part of the waste treatment operations we are using polymer filtration to remove Pu-238 to meet facility discharge limits. Polymer filtration (PF) technology uses water-soluble polymers prepared with selective receptor sites to sequester metal ions, organic molecules, and other species from dilute aqueous solutions. The water-soluble polymers have a sufilciently large molecular size that they can be separated and concentrated using ukmflltration (UF) methods. Water and small, unbound components of the solution pass freely through the UF membrane while the polymer concentrates in the retentate. The permeate stream is "cleaned" of the components bound to the polymer and can be used in further processing steps or discharged. The concentrated retentate solution can be treated to give a final waste form or to release the sequestered species from the reeeptor sites by adjusting the conditions in the retentate solution. The PF technology is part of our work to develop a safe, reliable and cost-effective scrap recovery operation with high process efficiencies, minimal waste generation, and high product purity. Form636