Review of recent developments in iodine wasteform production

Abstract

Radioiodine capture and immobilization is not only important to consider during the operation of reactors (i.e., I-131), during nuclear accidents (i.e., I-131 and I-129) or nuclear fuel reprocessing (i.e., I-131 and I-129), but also during disposal of nuclear wastes (i.e., I-129). Most disposal plans for I-129-containing waste forms (including spent nuclear fuel) propose to store them in underground repositories. Here, iodine can be highly mobile and, given its radiotoxicity, needs to be carefully managed to minimize long-term environmental impacts arising from disposal. Typically, any process that has been used to capture iodine from reprocessing or in a reactor is not suitable for direct disposal, rather conversion into a wasteform for disposal is required. The objectives of these materials are to use either chemical immobilization or physical encapsulation to reduce the leaching of iodine by groundwaters. Some of the more recent ideas have been to design capture materials that better align with disposal concepts, making the industrial processing requirements easier. Research on iodine capture materials and wasteforms has been extensive. This review will act as both an update on the state of the research since the last time it was comprehensively summarized, and an evaluation of the industrial techniques required to create the proposed iodine wasteforms in terms of resulting material chemistry and applicability.

Recent Advances in the Removal of Radioactive Iodine and Iodide from the Environment

“…Unfortunately, it is somehow difficult to really assess the advantages/disadvantages of each category. This is mainly due to their differences in composition, durability, stability, recyclability, efficiency, adsorption capabilities, and of course standardization protocols . However, LDHs and carbon-based materials are relatively easy to prepare.…”

“…This is mainly due to their differences in composition, durability, stability, recyclability, efficiency, adsorption capabilities, and of course standardization protocols. 47 However, LDHs and carbon-based materials are relatively easy to prepare. Although MOFs act as better I 2 /I − ion sensors, they are impractical for use in industrial-scale processes because they are usually prepared as powders.…”

“…The radioactive and stable isotopes of iodine are widespread in our environment, including soil and freshwater sources, and the production of iodine waste is inevitable, thus making it imperative to develop cost-effective and efficient technologies for the removal of iodine from the environment. Recently, Asmussen et al documented developments of iodine wasteform production . They described current efforts to develop materials capable of the capture, recovery conversion, and disposal of iodine.…”

“…Recently, Asmussen et al documented developments of iodine wasteform production. 47 They described current efforts to develop materials capable of the capture, recovery conversion, and disposal of iodine. They also mentioned the highly toxic radioiodine, which is an inevitable waste byproduct from nuclear fission released during standard operation of nuclear power plants or by accidents such as the Fukushima and Chernobyl disasters.…”

Densification and Immobilization of AgI-Containing Iodine Waste Forms Using Spark Plasma Sintering

“…Following loading, the final fate of the iodine-loaded material is called the waste form, which is an important consideration so that the long-lived 129 I, with a half-life ( t 1/2 ) of 1.57 × 10 7 y, will remain in a stable environmental configuration within a disposal facility. − Prior to disposal, a logical first step for porous sorbents is to perform a volume-reduction step to close the porosity. This is important because it can substantially reduce the volume occupied by the material in a repository, but it will also reduce the leachability of the material by closing off the porosity for groundwater to access.…”