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Advanced Fission Technologies and Systems
Published in William J. Nuttall, Nuclear Renaissance, 2022
A second key difference from conventional uranium-fuelled thermal critical reactors is that the Energy Amplifier uses thorium rather than uranium fuel. Thorium is roughly three times more abundant than uranium and as such is posited as the basis of a wholly new nuclear fuel cycle in the event that economic uranium resources are depleted. The use of thorium as a fission reactor fuel is interesting because thorium is not fissile. The key to the use of thorium is neutron capture by thorium-232 to form fissile uranium-233. While it is possible to construct a critical thorium/plutonium reactor the safety margins would be much tighter than in conventional uranium reactors as the fraction of delayed neutrons is lower in the thorium-based concept. In an ADS, where the level of criticality is maintained by an external neutron source, such concerns are much less burdensome [195]. Thorium has the added benefit of generating very few higher actinides (Po, Am, Cm, etc.) although this does not allow one to sidestep concerns around nuclear security and non-proliferation. We shall consider such aspects further in Section III.8.7.
Nuclear and Hydro Power
Published in Anco S. Blazev, Energy Security for The 21st Century, 2021
Thorium is a naturally occurring radioactive chemical element with the symbol Th and atomic number 90. In nature, virtually all thorium is found as Th-232, which has a half-life of about 14.05 billion years. Other isotopes of thorium are short-lived intermediates in the decay chains of higher elements, and only found in trace amounts. Thorium is mostly refined from monazite sands as a by-product of extracting rare earth metals.
The Other Energy Markets
Published in Anco S. Blazev, Global Energy Market Trends, 2021
Thorium is a naturally occurring radioactive chemical element with the symbol Th and atomic number 90. In nature, virtually all thorium is found as Th-232, which has a half-life of about 14.05 billion years. Other isotopes of thorium are short-lived intermediates in the decay chains of higher elements, and only found in trace amounts.
Investigation of foundation bed’s characteristics and environmental safety assessment in some parts of Bayelsa State, south–south Nigeria
Published in Cogent Engineering, 2022
Theophilus Aanuoluwa Adagunodo, Oyelowo Gabriel Bayowa, Ayobami Ismaila Ojoawo, Olusegun Oladotun Adewoyin, Patrick Omoregie Isibor, Emmanuel Ayibaifie Jephthah, Nicholas Oliseloke Anie
The wide variations in the compositions of these radioelements show that the study area is composed of series of lithological formations from depositional sediments and rock types (Akpan et al., 2016). The results showed that the background radiation in Ogbia and its environs contain partly 238U-enriched and highly 232Th-enriched soils across the surveyed region. As stated in the World Nuclear Association online library (WNA (World Nuclear Association), 2020), thorium is highly present in nature than uranium. It is fertile rather than being easily split. This characteristic has enabled thorium to be used as fuel together with recycled plutonium (a fossil material) in nuclear reactors. Thorium is a slightly radioactive metal that is naturally present in the subsurface. In some formations, thorium is found in small amounts while its abundance in other formations is about 300% than uranium. Thorium is insoluble when compared to uranium. This justifies why thorium is abundantly available in sands than uranium (WNA (World Nuclear Association), 2020). The transported thorium enriched materials and sediments during the deposition history of the Niger Delta could have been responsible for an elevated concentration of thorium in the study area which is higher than the global mean by a factor of 1.45.
Applications for Thorium in Multistage Fuel Cycles with Heavy Water Reactors
Published in Nuclear Technology, 2018
Timothy Ault, Steven Krahn, Andrew Worrall, Allen Croff
In order to understand the potential synergy of thorium and HWRs, it is helpful to review the basic neutronic properties of the thorium fuel cycle. Thorium is a naturally occurring element that is found exclusively as a single isotope: 232Th. The isotope 232Th is fertile but not fissile; upon undergoing a neutron capture, it becomes 233Th and undergoes two subsequent beta decays to become 233U, which is a fissile isotope. The relationship between 232Th and 233U is akin to that between 238U and 239Pu. The use of thorium and its associated isotopes has both advantages and disadvantages when compared to uranium and plutonium, depending on their application. These potential advantages and disadvantages have been reviewed at length in previous works (e.g., Refs. 1, 4, and 5). Among the most pertinent favorable properties of thorium and 233U in the context of this paper are the improved breeding performance of 232Th/233U compared to that of 238U/239Pu in the thermal neutron energy spectrum and a lower production of TRUs from neutron capture in 232Th/233U when compared to 238U/239Pu. A key shortcoming of thorium is the lack of a naturally occurring fissile isotope (in contrast to NU, which contains 0.71% fissile 235U) and the corresponding need to create new fissile material and/or use preexisting fissile material to initiate thorium-based breeding fuel cycles or to sustain nonbreeding thorium fuel cycles.
Safe, clean, proliferation resistant and cost-effective Thorium-based Molten Salt Reactors for sustainable development
Published in International Journal of Sustainable Energy, 2022
Thorium is 3–4 times more abundant than uranium and widely distributed in nature as an easily exploitable resource in many countries. Thorium fuels, therefore, both complement uranium fuels and ensure long term sustainability of nuclear power (IAEA 2005), and in the long term replace, or complement, uranium. Uranium-based nuclear power relies on U-235, which constitutes only 0.7% of natural uranium resources (David, Huffer, and Nifenecker 2007), whereas TMSR relies on U-233 and converts the thorium almost completely into energy, such that the real difference is roughly a factor of three hundred times as much output electric power per unit mass of raw fuel ore using a LFTR with closed-cycle gas turbine energy conversion (Juhasz, Rarick, and Rangarajan 2009).