Document Type

Report

Publication Date

2004

First page number:

1

Last page number:

6

Abstract

Immobilization of highly radioactive and long-lived isotope of 129I, which is a fission product in spent nuclear fuel, requires development of new durable host-materials.

Iodine is a very volatile chemical element, and even its chemically strong compounds such as AgI and CuI are not stable under ultraviolet irradiation or oxidizing conditions. Therefore, development of host materials for iodine immobilization is based on unusual approach – the search and testing of new compounds which were not studied before in respect of iodine sorption and strong fixation.

Laboratory of Applied Mineralogy and Radiogeochemistry of the V.G. Khlopin Radium Institute carries out investigation of prospective materials for iodine immobilization including transmutation since 1994. Some naturally occurring minerals such as tourmaline group, sodalite, apatite group were identified as possible host materials. However, these minerals are not suitable to be used as the targets for iodine transmutation.

Recently, a family of new discovered carbon molecules – fullerenes – was suggested for incorporation and strong fixation of highly radioactive elements. We have studied unseparated mixture of crystalline fullerenes and some pure fullerene fractions such as C60 and C70. These compounds were re-crystallized by evaporation of toluene solutions.

It was found that crystalline fullerenes phases are not effective for the iodine incorporation despite some interaction between crystalline C60 has been observed. Although FCC material demonstrated high loading capacity to iodine sorption it is necessary to take into account that FCC itself is not a final form of 129I immobilization. Either for disposal in geological formation or iodine transmutation in nuclear reactors the FCC should be converted into more chemically and mechanically durable material. In case of transmutation it is necessary to provide, also, an acceptable «transparency» of final material to neutron fluxes. Therefore, we decided to consider two main groups of durable compounds: silicon carbides and carbon nitrides (of fullerene structure) as possible targets of FCC conversion. It was assumed that synthesis of SixCy might be carried out at relatively low temperature as a result of chemical reaction between FCC and Si-organic chemicals. Successful synthesis of CxNy of fullerene-like structure using N-ion bombardment of carbon material was reported earlier. We propose that admixture of fullerenes in FCC will provide effect of “seeds” helping formation of CxNy of fullerene-like structure.

Keywords

Fullerenes; Iodine — Isotopes; Organic compounds; Radioactive wastes; Reactor fuel reprocessing; Sorbents

Controlled Subject

Iodine--Isotopes; Radioactive wastes; Sorbents

Disciplines

Chemistry | Oil, Gas, and Energy | Physical Chemistry

File Format

pdf

File Size

297 KB

Language

English

Comments

Signatures have been redacted for privacy and security measures.

Rights

COPYRIGHT UNDETERMINED. For more information about this rights statement, please visit http://rightsstatements.org/vocab/UND/1.0/

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