Immobilization of iodine via copper iodide

Abstract

CuI is a candidate wasteform for the immobilization of the fission product 129I. CuI can be made simply by the addition of CuCl to an I− bearing solution such that exchange of Cl− with I− takes place. The CuI material can then be consolidated into a wasteform by sintering at approximately 550 °C in argon or by hot isostatically pressing at 550 °C with 100 MPa of pressure. A waste loading of greater than 60 wt.% is achievable with good water leach resistance, in keeping with the low solubility product of CuI. However, like the well known wasteform candidate AgI, CuI decomposes in water containing metallic Fe. To compensate this deficiency, the sintered CuI wasteform can be further protected by surrounding it by Sn powder and HIPing at the low temperature of 200 °C.