Advanced reactor experiments for sodium fast reactor fuels (ARES) project; Transient irradiation experiments for metallic and MOX fuels

Jensen, C. B.*; Wachs, D. M.*; Woolstenhulme, N. E.*; Ozawa, Takayuki; Hirooka, Shun; Kato, Masato

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 9 Pages, 2022/04

Radiation-induced effects on the extraction properties of hexa--octylnitrilo-triacetamide (HONTA) complexes of americium and europium

Toigawa, Tomohiro; Peterman, D. R.*; Meeker, D. S.*; Grimes, T. S.*; Zalupski, P. R.*; Mezyk, S. P.*; Cook, A. R.*; Yamashita, Shinichi*; Kumagai, Yuta; Matsumura, Tatsuro; et al.

Physical Chemistry Chemical Physics, 23(2), p.1343 - 1351, 2021/01

https://doi.org/10.1039/D0CP05720G

The candidate An(III)/Ln(III) separation ligand hexa--octylnitrilo-triacetamide (HONTA) was irradiated under envisioned SELECT (Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation) process conditions using a solvent test loop in conjunction with cobalt-60 gamma irradiation. We demonstrate that HONTA undergoes exponential decay with increasing gamma dose to produce a range of degradation products which have been identified and quantified by HPLC-ESI-MS/MS techniques. The combination of HONTA destruction and degradation product ingrowth, particularly dioctylamine, negatively impacts the extraction and back-extraction of both americium and europium ions. The loss of HONTA was attributed to its reaction with the solvent (-dodecane) radical cation of (HONTA + R) = (7.61 0.82) 10 M s obtained by pulse radiolysis techniques. However, when this ligand is bound to either americium or europium ions, the observed -dodecane radical cation kinetics increase by over an order of magnitude. This large reactivity increase to additional reaction pathways occurring upon metal-ion binding. Lastly nanosecond time-resolved measurements showed that both direct and indirect HONTA radiolysis yielded the short-lived (100 ns) HONTA radical cation as well as a longer-lived (s) HONTA triplet excited state. These HONTA species are important precursors to the suite of HONTA degradation products observed.

Demonstration research on fast reactor recycling using low decontaminated MA-bearing MOX fuels, 6; ARES-MOX transient program for irradiated MOX fuels in TREAT

Ozawa, Takayuki; Hirooka, Shun; Kato, Masato; Smuin, T. J.*; Jensen, C. B.*; Woolstenhulme, N. E.*; Wachs, D. M.*

no journal, , 

The ARES-MOX transient program is planned in TREAT by using MOX fuels irradiated in SPA-2 irradiation tests in EBR-II, which was conducted in 1984-1994 under the international collaboration between US and Japan, and have been stored in the current INL. The MOX fuels irradiated up to the maximum burnup of about 130 GWd/t in EBR-II includes the solid FP content of about 10 wt.%. In this program, the objectives are to acquire not only valuable data to develop the FCMI threshold for high-burnup annular MOX fuels but also knowledge about irradiation behavior of FP at transient. The overview of ARES-MOX program, schedule and outcomes expected from fuel performance calculation for annular MOX fuels irradiated in EBR-II will be introduced here.

Two dimensional analyses for pore migration behaviour to affect the MA-bearing MOX fuel restructuring

Ozawa, Takayuki; Hirooka, Shun; Kato, Masato; Novascone, S.*; Medvedev, P.*

no journal, , 

To evaluate the O/M dependence of pore migration regarding fuel restructuring at the beginning of irradiation, we are developing BISON for MOX in cooperation with INL and have installed pore migration model considering vapor pressure of vapor species and thermal conductivity for MOX. The O/M dependence of fuel restructuring observed in MA-bearing MOX irradiation experiment in Joyo was evaluated by the 2-dimensional analyses. Four MA-bearing MOX pins with different O/M ratio and pellet/cladding gap size were irradiated in Joyo B14 experiment. Remarkable restructuring of stoichiometric MA-bearing MOX fuels was observed in PIE, and could be evaluated by considering the influence of O/M ratio on vapor pressure. Also, a central void assumes to move toward wide-gap side when the pellet eccentricity taking place, but 2-dimentional analyses on pellet transverse section revealed that the central void formation observed in PIE would be inconsistent with a direction of the pellet eccentricity.