The Use of Surrogates in Waste Immobilization Studies: A Case Study of Plutonium

Abstract

Surrogates are widely used in the research and development of nuclear wasteforms, providing detailed insight into the chemical and physical behaviour of the wasteform whilst avoiding the widespread (restricted and costly) use of radiotoxic elements in the laboratory. However, caution must be exercised when dealing with surrogates since no single element or compound perfectly mimics all aspects of the behaviour of another. In this paper we present a broad discussion of the use of surrogates in waste immobilization, drawing upon and highlighting our research into glass and ceramic wasteforms for the immobilization of bulk PuO 2 .

Thermal Properties of LiCl-KCl Molten Salt for Nuclear Waste Separation

“…The lanthanides act similarly to the actinides yet lack the radiation risks which significantly complicate experimental procedures. There are several factors that should be considered when determining whether an element can serve as a suitable surrogate for an actinide [8] Lanthanides are generally good surrogates for actinides given that both groups are Lewis acids, have large ionic radii, and possess flexible coordination geometries that prefer high coordination numbers. The most common lanthanide surrogates for uranium and plutonium are Ce, Eu, Nd, Gd, La, and Sm [8].…”

The fluorite related modulated structures of the Gd2(Zr2−xCex)O7 solid solution: An analogue for Pu disposition

“…This study focussed on characterisation of the Gd 2 (Zr 2À x Ce x )O 7 solid solution, where cerium was used as an inactive surrogate for plutonium. Tetravalent cerium has a very similar ionic radius to tetravalent plutonium (for a given coordination number) making it a good surrogate from a crystallographic viewpoint [8]. This solid solution and related rare earth oxide pyrochlores, is also of interest for application as a solid electrolyte in solid oxide fuel cells [9][10][11].…”

Ceramic formulation and processing design for plutonium disposition

“…Based on these two pre-requisites, a single-stage reactive sintering route was developed, as shown in Figure 1. After evaluation of the available plutonium oxide surrogates previously used in the literature [14], CeO 2 and depleted 238 UO 2 were selected as PuO 2 surrogates for this study. In addition to investigation of the surrogate solid solution limits (i.e.…”