Plasma Mass Filters For Nuclear Waste Reprocessing

Abstract

Practical disposal of nuclear waste requires high-throughput separation techniques. The most dangerous part of nuclear waste is the fission product, which contains the most active and mobile radioisotopes and produces most of the heat. We suggest that the fission products could be separated as a group from nuclear waste using plasma mass filters. Plasmabased processes are well suited to separating nuclear waste, because mass rather than chemical properties are used for separation. A single plasma stage can replace several stages of chemical separation, producing separate streams of bulk elements, fission products, and actinoids. The plasma mass filters may have lower cost and produce less auxiliary waste than chemical processing plants. Three rotating plasma configurations are considered that act as mass filters: the plasma centrifuge, the Ohkawa filter, and the asymmetric centrifugal trap.

Study of Atmospheric Plasma-Based Mass Separation System for High-Level Radioactive Waste Treatment

“…[19]. Although no practical device was built to demonstrate the plasma centrifuge in HLRW mass separation, the concept was presented as one of the potential mass separation methods for HLRW management through mass separation by Abraham J. Fetermana and Nathaniel J. Fischa from the Department of Astrophysical Sciences, Princeton University, in 2011 [9].…”

“…Since 2010, the most active experiments on plasma-based mass separation have been carried out at Irkutsk, Russia [23], plasma mass filter experiments (PMFX) at Princeton Plasma Lab [24], and spent nuclear fuel (SNF) processing at the Joint Institute for High Temperatures in Moscow [25]. Of all the plasma-based mass separation experiments, plasma centrifuge, Archimedes filter, plasma mass filter and SNF separator system are applicable for nuclear waste mass separation, especially HLRW and spent nuclear fuel [9,12,19,25]. The Archimedes filter, plasma mass filter, and SNF separator system are applicable for separating elements (atoms) in a mass group rather than individual elements.…”

“…For plasma mass separation to dramatically change HLRW processing in the future, the process should cost USD200/kgHM [31] since the plasma mass separation system has a relatively smaller footprint than other systems, in addition to reduced construction, maintenance, and operation costs. Additionally, with zero additional cost of vitrification for waste immobilization, a 2 B USD budget for processing 500 tHM in 20 years would keep the processing cost < USD200/kgHM [9].…”

“…According to the mass profile, spent fuel rods are composed of approximately 3-4% fission products, the most radioactive elements, which contribute to 99.8% of the radioactivity via gamma and beta emissions; the remaining 96-97% masses are actinides that contribute to long-term and 0.2% overall radioactivity, primarily through alpha emissions [9]. In the case of liquid HLRW from spent fuel processing, like the Hanford site, 98.9% of the mass consists of non-radioactive bulk elements with 0.1% radioactivity, 0.7% fission products with 99.7% radioactivity, and 0.4% actinides with 0.2% radioactivity.…”

“…A traditional spent fuel processing plant can separate the actinides from the fission products. The process also creates a large residue volume of liquid HLRW as the first and second cycles of raffinate liquid mainly contain nitric acid, fission products, and minor actinides besides uranium and plutonium [9,10]. A thermal plasma-based mass separation system provides a unique opportunity for separating the bulk elements, fission products, and actinides as a mass group with high throughput without producing residual waste.…”