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The Other Energy Markets
Published in Anco S. Blazev, Global Energy Market Trends, 2021
TRIGA fuel was originally designed to use highly enriched uranium, however in 1978 the U.S. Department of Energy launched its Reduced Enrichment for Research Test Reactors program, which promoted reactor conversion to low-enriched uranium fuel. A total of 35 TRIGA reactors have been installed at locations across the USA. Anotherr 35 reactors have been installed in other countries. Actinide nuclear fuel is a by-product of fast neutron reactors, where minor actinides produced by neutron capture of uranium and plutonium can be used as fuel. Metal actinide fuel is typically an alloy of zirconium, uranium, plutonium and the minor actinides. It can be made inherently safe as thermal expansion of the metal alloy will increase neutron leakage.
Nuclear Fuel Recycling
Published in Kenneth D. Kok, Nuclear Engineering Handbook, 2016
Patricia Paviet, Michael F. Simpson
For future advanced nuclear systems, minor actinides are considered more as a resource to be recycled and transmuted than to be disposed of directly into a nuclear repository. A key feature of advanced fuel cycles technologies would be to separate MA and ultimately americium from curium. Several countries are investigating the separation of MA from a PUREX/COEXTM based process raffinate or a modified PUREX process raffinate using new extractant molecules with two potential options for actinide separations: A selective separation of MA for interim storage, pending a decision regarding their transmutation in heterogeneous recycling mode either in fast reactor (blankets) or in ADS. As an example, the DIAMide EXtraction (DIAMEX)/Selective ActiNide EXtraction (SANEX) processes developed in France (Serrano-Purroy et al., 2005), TRUEX/TALSPEAK processes developed in the United States (Nilsson and Nash, 2007, 2009; Vandegrift and Regalbuto, 1995), ARTIST process developed in Japan) (Figure 14.25) are aiming to separate selectively MA.Other simplified processes are aiming to separate a group of actinides using an integrated fuel cycle (with online fuel recycling and re-fabrication) with the prospect of their homogeneous recycling in a fast reactor (i-SANEX and GANEX processes developed in Europe, TRUSPEAK process developed in the USA).
Introduction
Published in G. Vaidyanathan, Dynamic Simulation of Sodium Cooled Fast Reactors, 2023
After recovering U and Pu from spent nuclear fuel of thermal reactors (PWR, BWR, PHWR) by conventional reprocessing, the disposal of high-level radioactive wastes is a major concern in many countries. Most of the radioactive hazard remaining in high-level radioactive wastes after thousands of years comes from minor actinides (MA); isotopes of Np, Am, and Cm, and some long-lived fission products (LLFPs; Se79, Zr93, Tc99, Pd107, I129, and Cs135).
Gamma Radiolysis of Phenyl-Substituted TODGAs: Part II
Published in Solvent Extraction and Ion Exchange, 2023
Christopher A. Zarzana, Jack McAlpine, Andreas Wilden, Michelle Hupert, Andrea Stärk, Mudassir Iqbal, Willem Verboom, Aspen N. Vandevender, Bruce J. Mincher, Gary S. Groenewold, Giuseppe Modolo
Partitioning and transmutation (P&T) schemes are of interest as one way to reduce the total volume of radioactive material that requires deep geologic storage.[7,8] Briefly, P&T schemes aim to extract the bulk uranium, plutonium, and neptunium out of the used nuclear fuel. The raffinate left after this extraction step contains fission products, lanthanides (Ln), and the minor actinides (An) americium (Am) and curium (Cm). As the heat from the radioactive decay of americium is the dominant contribution to waste-form heat load from approximately 200–2000 years after removal from a reactor,[4] one central aim of the concept of P&T is removal of the minor actinides from the remainder of the used fuel.[7] Once removed, the minor actinides can be burned in a fast neutron spectrum reactor, yielding more energy and converting the minor actinides into short-lived fission products.[9,10]
Neutron capture cross sections of curium isotopes measured with ANNRI at J-PARC
Published in Journal of Nuclear Science and Technology, 2021
Shoichiro Kawase, Atsushi Kimura, Hideo Harada, Nobuyuki Iwamoto, Osamu Iwamoto, Shoji Nakamura, Mariko Segawa, Yosuke Toh
Minor actinides (MA) are generated in nuclear power plants through the reaction chains of neutron captures and alpha/beta decays starting from uranium. Some innovative reactors such as Accelerator-Driven Systems (ADS) and associated fuel cycles are intensively investigated [1,2] to reduce MAs’ long-lasting radiotoxicity in the spent fuels. For this purpose, accurate neutron capture cross section data on MAs are needed. Among MA isotopes, ( [3]) has importance in treating radioactive waste as holds a significant share in the source of decay heat and has a large neutron emission rate in spent fuels. Neutron capture cross section data for ( [3]) is also important because it is being part of production chain. However, accurate measurement of those cross sections has been highly challenging due to their highly specific activities.
Minor Actinide Transmutation in Supercritical-CO2-Cooled and Sodium-Cooled Fast Reactors with Low Burnup Reactivity Swings
Published in Nuclear Technology, 2019
Hoai-Nam Tran, Yasuyoshi Kato, Peng Hong Liem, Van-Khanh Hoang, Sy Minh Tuan Hoang
A light water reactor (LWR) with an electrical output of 1000 MW(electric) and average discharged burnup of 33 GWd/tonne produces about 24 kg of minor actinides (MAs) per year. In the total MAs discharged from the spent fuel of LWRs, neptunium (Np) constitutes about 50%; americium (Am) is 45%, and curium (Cm) constitutes the remainder of about 5%. Minor actinides are disposed of geologically as long-lived radioactive waste, whereas Am and Cm contribute to most of the radiotoxic inventory of spent fuel after 250 years of storage.1 Therefore, transmutation of MAs would contribute to the reduction of long-lived radioactive waste inventory. This process is efficient in a hard neutron spectrum by minimizing the production of higher MAs through neutron capture reactions. Subcritical accelerator-driven systems and fast reactors (FRs) could play a significant role in the transmutation of MAs (Ref. 2). Fast reactors, also known as MA burners, can transmute MAs to short-lived nuclides and minimize higher radioactive products by taking advantage of their hard neutron spectrum. Extensive studies to transmute MAs and fission products have been undertaken.1–3