Multi-Column Experimental Test Bed Using CaSDB MOF for Xe/Kr Separation

Abstract

Nuclear fuel reprocessing produces off-gas streams containing several radioactive components that must be captured for further treatment or storage. As part of the Off-Gas Sigma Team, parallel research at INL and PNNL has produced several promising sorbents for the selective capture of xenon and krypton from surrogate off-gas stream compositions. In order to design full-scale treatment systems, sorbents that are promising on a laboratory scale must be tested under process conditions prior to consideration for pilot testing and eventual full-scale application. To that end, a bench-scale multi-column system with capability to test multiple sorbents was designed and constructed at INL. This report details multi-column testing of CaSDB MOF produced at PNNL.

Initial Evaluation of CaSDB MOF Xe and Kr Capacities

“…Most likely, the sorbent material was damaged during shipping. As seen previously with this material, abrasion from handling causes it to break down to powder (Welty, Garn, & Greenhalgh, 2016). Initial weight of the sample was 18.99 g. The entire sample was carefully transferred to a one inch diameter column for activation.…”

“…Brunauer-Emmet-Teller (BET) surface area was measured using a Micromeritics ASAP 2020 and found to be 81 m 2 /g. Previous CaSDB MOF had a BET surface area of 4 m 2 /g and a density of 0.740 g/mL (Welty, Garn, & Greenhalgh, 2016).…”

“…That testing indicated good saturation capacity for Xe, but a low Xe capacity at initial breakthrough. The breakdown of the material to fine dust during handling and use was of concern as well (Welty, Garn, & Greenhalgh, 2016).…”

Investigating the Effects of Ag, Cu, and Pd Functionalized Chabazite on the Adsorption Affinities of Noble Gases Xe, Kr, and Ar

“…Xe in particular has been proposed as an anesthetic, , and all three noble gases are used in specialized types of lighting. In addition to these practical uses, the atmospheric detection of Xe is used for monitoring undeclared nuclear tests for the purpose of verification of the Comprehensive Nuclear Test Ban Treaty. , Adsorbents such as metal–organic frameworks (MOFs) are also being considered for the collection of Kr from spent nuclear fuel. − However, finding an efficient and cost-effective method for the capture and separation of noble gases (especially Kr and Xe) from air has proven to be technologically challenging. Generally, the commercial separation of these gases from air involves a cryogenic distillation process that is both energy intensive and expensive.…”