(PDF) Thorium for Sustainable Nuclear Energy

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All Sciences Proceedingshttp://as-proceeding.com/2nd International Conference on RecentAcademic StudiesOctober 19-20, 2023 : Konya, Turkeyhttps://as-proceeding.com/index.php/icras© 2023 Published by All Sciences ProceedingsThorium for Sustainable Nuclear EnergyRafika HELAIMIADepartment of English, Universityof MCM, Soukahras,Algeriar.helaimia@univ-soukahras.dzAbstract – Since the 1950s, there has been interest in using thorium in the nuclear fuel cycle as aprimary source of nuclear energy. This is due to its practicality and its likelihood of not becoming scarcein the future. However, in the 2000s, there was a revolution in the international arena to addressenvironmental, economic, and political issues such as global warming, greenhouse gas emissions,depletion of fossil fuels, nuclear proliferation dangers, lack of energy access, and insecurity. The goal ofimplementing a new nuclear strategy is to substitute thorium for uranium as a source of nuclear energy.This is because thorium is naturally abundant and helps to reduce the risk of nuclear accidents andradioactive contamination. Nevertheless, certain nations have faced obstacles in altering their nuclearapproach, mainly due to concerns about the risks associated with nuclear proliferation. But, there areongoing endeavors to realize a significant climate change stabilizing wedge through the implementationof thorium-based reactors. This article explains the properties of thorium, outlines the advantages of usingit, and highlights any limitations to its application, with the aim of addressing these concerns.Keywords – thorium, sources, uranium, drivers, energy, limitationsI. INTRODUCTIONThere has been a lot of interest in using thoriumas a part of the nuclear fuel cycle since the 20thcentury. This interest has increased due to issuessuch as the need to reduce greenhouse gasemissions and find a new, reliable, and cost-effective energy source. To achieve moresustainable and diverse sources of energy,strategies and scenarios have been proposed. Onesuch strategy is thorium nuclear energy production,which some countries have adopted despitechallenges and restrictions. This is because theybelieve that more nuclear energy is necessary foreconomic and secure development. Thorium hasfavorable characteristics such as abundance, lackof long-lived α emitters, and reduced greenhousegas emissions.II. OVERVIEW OF NUCLEAR FUEL SOURCES ANDPRODUCTIONAs we strive for global progress, it is crucial toensure a reliable energy supply and promotesustainable energy sources. Despite a decline in somedeveloped countries, the demand for electricity isexpected to increase in the future due to populationgrowth. Meeting this growing demand is essential forachieving energy security and sustainable developmentgoals (1). Nuclear power is widely considered the mostcost-effective and eco-friendly energy source due to itslow cost and minimal gas emissions. Many countriesare expected to increase their nuclear power capacityto 82% by 2025 from 7% in 2015 (2). Uranium andthorium are commonly used to produce nuclearenergy. UraniumUranium is a commonly found element in theearth's crust and is primarily used as fuel inreactors. In its natural state, uranium is composedof 99.3% 238U, 0.7% 235U, and small amounts of1

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234U. To be utilized in the nuclear fuel cycle, itmust first be separated from its ore and convertedinto a usable form.Uranium extraction involves varioustechniques, including open-cut and undergroundmining. Sometimes, copper mining can lead to thediscovery of uranium as a byproduct. The usualmethod of processing mined uranium ores is togrind them into a uniform consistency and thenextract uranium with chemical leaching. Thisprocess often results in the creation of"yellowcake," a dry powder that contains about75% naturally occurring uranium. The"yellowcake" is then sold as U3O8 on the uraniummarket(3).Fig.1 Uranium globaldistribution(https://www.selfstudyforias.com/uranium-and-thorium/) ThoriumThorium is being considered for use in the fuelcycle due to its ability to reduce minor actinideproduction, as per the IAEA in 2012. Over the pastfifteen years, research on thorium-based fuels forcurrent or evolutionary (generation III+) reactorshas gained more attention. Thorium can be a usefuladdition to the uranium-plutonium fuel cycle, as itcan help manage radioactive waste and spent fuels,and provide a solution for dealing with plutoniumstockpiles without fast reactors. Additionally,thorium may offer flexibility in light ofuncertainties about the long-term availability ofreasonably priced uranium (15).The primary source of thorium is the mineralphosphate monazite, which has the highestconcentration of thorium among other mineralswith a ThO2 content ranging from 3.1% to 11.34%(16).To extract thorium from the mineralmonazite two main processes are required: aciddigestion and leaching. During the acid digestionprocess, sulfuric acid is utilized to break down themonazite and is then heated to 230 C for fourhours. Afterwards, a selective precipitation methodis employed to separate thorium from uranium andrare earth elements (REE) using ammoniumhydroxide (NH4OH), sodium hydroxide (NaOH),and hydrogen peroxide (H2O2) (17) (18). It isconfirmed that 97.68% of the thorium can beseparated at a pH of 1.05e1.84 (19).Fig.2 Thorium global distribution(https://www.pmfias.com/uranium-thorium-distribution-advantages-uranium-india-nuclear-power-plants)III. DRIVERS OF THORIUM CONSUMPTIONDespite economic, environmental, and energyfactors like the financial crisis, the FukushimaDaiichi accident in 2011, and the booming gastendency affecting the development of nuclearenergy production, a number of countries decidedto develop the use of thorium to build new nuclearplans. Reasons include: Thorium is abundant in nature.Thorium (Th) is an element that is three timesmore common in nature than uranium. The isotope232Th accounts for the majority of natural thorium,2

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while other isotopes may exist in trace amounts orbe produced artificially. Thorium makes up only0.0006% (6,000 ppb) of the Earth's crust,compared to uranium which makes up 0.00018%of the crust. Thorium is radioactive and has a half-life of 1.4 1010 years, while uranium-238 has ahalf-life of 4.5 109 years. Due to its longer half-life, thorium is more prevalent than uranium in theEarth's crust, with an average concentration of 7.2ppm (parts per million). These characteristicsdemonstrate the unique nature of thorium.FİG.3 THORİUM WORLDRESERVES(https://www.frontiersin.org/articles/10.3389/fenrg.2023.1132611/full Thorium is a Fertile MaterialUnlike uranium, which is fissile, thorium is anuclear fertile source. Thorium (232Th) is aradioactive element that can capture neutrons andbecome 233Th, which then undergoes double betadecay to produce fissile 233U, a nuclear fuel (5).Besides, some of the Th232 transforms into U233by absorbing neutrons inside a reactor, which iswhy thorium is classified as "fertile" instead of"fissile" .Uranium-232 is preferred over uranium-238 for producing waste that does not contain long-lived emitters because it hardly producesplutonium or other transuranic elements (6).Furthermore, adding thorium to ADS allowstransuranium or plutonium to burn withoutrequiring uranium-238. These systems not onlyhave low radiotoxicity of waste but also provideimproved safety features and greater breedingflexibility (7). Thorium is crucial for thesustainability of advanced nuclear reactor designs,like Generation IV and beyond, because itsconversion ratio is equal to or greater than 1(8).Fig. 4 Thorium materials(https://academic-accelerator.com/encyclopedia/fertile-material) Thorium is Potentially a Non-proliferationBreederA potential solution for non-proliferation is theuse of thorium as a matrix fuel. This can aid inburning additional fissile materials in an open fuelcycle mode. By combining thorium with otherfuels, it is possible to create powerful fuels withhighly enriched uranium or plutonium. These fuelscan be used in reactors to improve the rate at whichfissile material is consumed. As a result, thisprocedure can speed up the removal of potentiallydangerous fissile material (14).IV.THORIUM FOR NUCLEAR ENERGY PRODUCTIONThe utilization of thorium as a newalternative source of energy has been a tantalizingprospect years ago. Thorium has been used as asource of energy since the end of World War II.Between 1950 and 1960, many advancements weremade, including the development of multiplethorium prototypes. Currently, three mainprograms are focused on developing thoriumnuclear fuel (7):The long-term goal of the Indian program is to useAdvanced Heavy Water Reactors for burningthorium, uranium-233, and plutonium.The Molten Salt Reactor is one of six ideas createdby the Generation IV International Forum (GIF).3