Initial Demonstration of the Vitrification of High-Level Nuclear Waste Sludge Containing an Organic Cs-Loaded Ion-Exchange Resin

Abstract

When immobilizing into borosilicate glass the radionuclides in the caustic high-level radioactive wastes stored in the USA, the soluble fission product Cs-137 has to be removed from supernates of the wastes. In the current processes zeolites or an organic precipitant will be used to remove the Cs. These are then treated further and mixed with the radioactive sludges and vitrified into a borosilicate glass. This paper describes the vitrification of a mixture resulting from using a new process to remove Cs from the caustic supernate. A resorcinol based organic ion exchange resin is used. This resin was then mixed with sludge and frit and vitrified. Using an organic ion exchange resin rather than zeolite or the organic precipitant has certain advantages. For example, use of the zeolite increases the amount of glass to be made and use of the organic precipitant produces benzene as a secondary waste stream. Results in the paper indicate that a mixture of the resin, sludge and frit can be successfully vitrified in a joule-heated, slurry fed melter. However, when resin is present in the feed, the glass becomes less durable due to the increased amount of Fe(II) caused by reduction of Fe(III) in the melt. Based on the durabilities of other waste glasses, this glass is still suitable as a canistered wasteform.

Treatment of Spent Argentine Ion Exchange Resin Using Vitrification - Results of FY01 Testing at the Savannah River Technology Center

“…In the late 1980s, SRTC performed vitrification studies with resorcinol-based organic ion exchange resin (Bibler, 1992). These early studies indicated that only low levels of resins could be fed to the small-scale Joule-heated ceramic melter.…”

Evaluation of interim and final waste forms for the newly generated liquid low-level waste flowsheet

“…The maximum cesium release of 4.0% occurred after 50 d of leaching at 70°C in HCI solution at pH 1.0; the mi ni mum loss was 0.17% in HC1 solution at pH 4.0. Bibler et al (1993) have reported that the vitrification of sludge, fiit, and a resorcinol-based ion-exchange resin used to remove 137Cs fiom a supernate resulted in the formation of low-durability glass, as indicated by high rates of boron, lithium, silicon, and sodium leaching from the glass.…”

Fiscal year 1995 final report for TTP SR-1320-04

“…For t h e I D M S , it has been found t o r e d u c e t h e Hg c o n t e n t t o below t h e p e r m i t t e d l e v e l of 1 0 pg/L f o r subsequent p r o c e s s i n g and e f f l u e n t h a s been <5 pg/L H g . 4 T h i s r e s i n w a s a polystyrene/divinylbenzene r e s i n O b s e r v a t i o n s f o r e a c h of t h e runs p e r t a i n i n g t o t h e o f f g a s system a r e d i s c u s s e d below. WSRC-TR-95-0404, Rev.0 I A f t e r t h e feed p r e p a r a t i o n s t e p , no m e t a l l i c mercury had accumulated i n t h e mercury sump o f t h e MWWT.…”

“…from a s i m u l a t e d HLW s u p e r n a t e i s g i v e n i n Table l . 4 T h e t y p i c a l composition of t h e dried r e s i n a f t e r C s removal I n t h e commercial n u c l e a r power s e c t o r , ion-exchange r e s i n s g e n e r a t e d as wastes r e q u i r e p r o c e s s i n g p r…”