Koyama, SI; Suzuki, T; Mimura, H; Fujita, R; Kurosawa, K; Okada, Ken; Ozawa, M
For minimization of the ecological risks inherent in
nuclear fuel recycling, a new fuel cycle paradigm was proposed and its key technology
developments have been carried out as a part of the Advanced Optimization by Recycling
Instructive Elements (Adv.-ORIENT) Cycle strategy. The basic concept of the Adv.-ORIENT Cycle
uses a three-pronged approach, separation, transmutation and utilization of nuclides and
elements, based on the FBR fuel cycle. Fundamental research studies done in Adv.-OEIENT Cycle
[Phase-1: 2006-2010] have led to the following findings. 1. Cs and Sr separation and its
utilization: Silica gel loaded with ammonium molybdophosphate (AMP) and hybrid organic
microcapsules with crown ether D18C6 were investigated to chromatographically separate Cs and Sr,
respectively. In particular, uptake experiments of Cs from solution simulating the spent fuel
solution obtained were carried out by a batch method, and the uptake rates achieved were more
than 90%. 2. Minor actinide (MA)/lanthanide/fission product (FP) separation: A tertiary pyridine
type resin (TPR) can be used to recover Am, Cm and lantanide elements with a high separation
factor by a chromatographic method from spent fuel solution. The TPR can be used with
hydrochloric acid (HCl) as well as nitric acid (HNO(3)). 3. Ru, Ph, Pd and Tc separation: A
catalytic electrolytic extraction (CEE) method can effectively separate Ru, Ph, Pd and Tc. High
recovery ratios of Ru, Rh, Pd, Tc, Se, etc. were achieved using HCl solutions. Rh co-deposition
significantly accelerated reduction of Ru, Tc and Re using HNO(3) solutions. 4. Ru, Ph, Pd and Tc
utilization: Based on the mixed deposit obtained from the CEE experiments, Ru/Rh/Pd/Tc(Re)-Pt
electrodes provided the highest catalytic reactivity in the electrolytic production of hydrogen
in an alkali solution. 5. Basic engineering research: Results of corrosion experiments showed
that Hastelloy-B and Ta had a good anti-corrosive property in a wide range of HCl concentrations.
The basic thermo-chemical stability of TPR and tri-butyl phosphorous (TBP, as a reference) was
also experimentally studied, and the process safety conditions to be specified for practical use
of TPR could be identified. (C) 2011 Elsevier Ltd. All rights reserved.