Pyroprocess Experiments at ENEA Laboratories

Abstract

A new facility, known as Pyrel III, has been installed at ENEA laboratories for pyrochemical process studies under inactive conditions. It is a pilot plant which allows electrorening and electroreduction experiments to be conducted on simulated fuel. The main component of the plant is a zirconia crucible. The crucible is heated by a furnace which is supported in an externally water-cooled well under the oor of a steel glove-box, where an argon atmosphere is maintained by a continual purge of about 10 L·min-1. The vessel is loaded with LiCl-KCl eutectic salt (59-41 mol%) and is currently operated at 460 °C. Several improvements on Pyrel II (the previous operating plant) have been introduced into Pyrel III. They are described in detail, together with the results from the rst experimental campaign which used lanthanum metal.Moreover, studies about the treatment of chloride salt wastes from pyroprocesses have been conducted in parallel. They follow two main routes: on one hand, a matrix termed sodalite, a naturally occurring mineral containing chlorine, has been synthesized from a mix of nepheline, simulated exhausted salts and glass frit; on the other hand, a novel method proposed by Korea Atomic Energy Research Institute (KAERI) is under assessment. The nal waste forms have been fully characterized with the support of the Politechnique of Milan, by means of density measurements, thermal analysis, and stereomicroscopy observations, FTIR, XRD, and RAMAN spectra, as well as leach tests under static conditions \ud \ud Pyroprocess Experiments at ENEA Laboratories (PDF Download Available). Available from: https://www.researchgate.net/publication/296335513_Pyroprocess_Experiments_at_ENEA_Laboratories [accessed Apr 28, 2016]

An experimental study on Sodalite and SAP matrices for immobilization of spent chloride salt waste

“…Among the fission elements present in the chloride salt (i.e. Rb, Sr, Cs, Ba, La, Nd) notable releases of Rb and Cs have been observed in solution immediately from the beginning of leaching tests performed by the present authors [23,25,29]. The leaching tests at 90 ± 2 C show a similar behavior with some differences (Fig.…”

“…1 clearly shows that the XRD spectrum of CSW.SOD.GF obtained at 925 C after 7 h well correspond to the sodalite phase. The same conclusion was confirmed by FT-IR analyses of CSW.SOD.GF that showed the presence of the characteristic peaks of sodalite [25]. Therefore, a thermal treatment of 7 h at 925 C was identified as effective in obtaining a final product essentially composed of sodalite (JCPDS card 37-0476).…”

“…An attempt was made to collect as much as possible literature data comparable with the results of the present study. For this purpose, Table 3 reports herein obtained data and literature results related to: analogous ceramic wasteforms previously studied by the present authors [24,25,30]; ceramic waste forms containing sodalite with the addition of 25 wt% glass frit, synthesized at Argonne National Laboratory…”

“…The so-obtained SOD-and SAP-based matrices were characterized by density measurements, X-ray diffraction with a Bruker AXS D8 ADVANCE diffractometer employing a Cu-Ka radiation (l ¼ 1.5418 Å) and by Fourier-transform infrared spectroscopy on a Perkin Elmer FT1600 analyzer. Moreover, SEM-EDS and thermogravimetric analyses were performed in order to assess the nature of the matrices before the leaching tests [25,29]. Finally, SEM analyses were also carried out on powder before and after leaching tests by a Zeiss Supra 40 microscope equipped with a GEMINI column (EHT ¼ 2e3 kV).…”