- Nuclear Power generation fueled by Thorium (atomic no. 90)
- A nuclear reactor consumes certain specific fissile isotopes to produce energy. Uranium-233, transformed from thorium-232, derived from natural mined thorium is used as nuclear reactor fuel
2) Energy Generation
a. Uranium-233 as a nuclear fuel
- Thorium (Th-232) is not itself fissile so is not directly usable in a thermal neutron reactor. However, it is fertile and upon absorbing a neutron will transmute to uranium-233, which can be an excellent fissile fuel material.
b. Fission chain reaction
- The fission of uranium-233 doesn't release enough neutrons to kick off chain reactions
- To use uranium-233(derived from thorium) as a nuclear reactor fuel, more neutrons must be pumped into the reactor to keep it going
- Mix the thorium with transuranium nuclide (the chemical elements with atomic numbers greater than uranium (atomic no. 92) such as enriched uranium 235, uranium 238, or plutonium)
- Sub-critical reactor coupled with high intensity proton accelerator called accelerator-driven systems (ADSs): High-energy accelerators or cyclotrons can produce neutrons by spallation. The neutrons produced by spallation would cause fission in the thorium based fuel, assisted by further neutrons arising from that fission
Science Writer Richard Martin : Thorium could provide a clean and effectively limitless source of power while allaying all public concern-weapon proliferation, radioactive pollution, toxic waste, and fuel that is both costly and complicated process.
- Uranium itself is fissile material: Once nuclear fission starts, it produces the massive concentrations of radioactive materials and the huge amount of heat. Cooling system is required for cooling them down. When the accidents and disasters such as earthquakes occur, they can cause failures in cooling systems and cause meltdowns→nuclear disaster
Ex) Fukushima nuclear accident
- As thorium can't split to make a nuclear chain reaction (is not fissile on its own), reactions could be stopped in case of emergency such as blackout.
- ThorCon liquid-fuel reactor, newly designed by Martingale Inc in USA, is a complete system of power generation module. There are four barriers between the fuel salt and the atmosphere. ThorCon is walk-away safe
- Hazardous nuclear waste production rate is a thousand times less than uranium.
- Zero CO2 emission
- In thorium based nuclear reactor, 100% of natural thorium can be used as a fuel. An accelerator-driven system including fast reactor can be used to burn transuranium nuclide contained in the used fuel from a conventional nuclear reactor.
- The radioactivity of the resulting waste also drops down to safe levels after a few hundred years, compared to tens of thousands years needed for current nuclear waste to cool off.
d. Nuclear Weapon nonproliferation
- Thorium reactor’s plutonium production rate would be less than 2% of that of a standard reactor.
- It is easy to build nuclear weapon because conventional uranium reactor produce nuclear waste containin enough plutonium ← the real reasons of using uranium over thorium in cold war-era.
e. Efficiency (1ton of Thorium vs. 250tons of Uranium): One ton of thorium can produce as much energy as 250tons of uranium, or 3,500,000tons of coal(Dr. Carlo Rubbia). Liquid fluoride thorium reactor(LFTR) can generate 1GW of electricity for 1 year with 1 ton of thorium
- Conventional reactors (Uranium based nuclear reactor): 250 tons of uranium per year for 1GW plant are required. From them only 35 tons of enriched uranium (containing 1. 15 tons of U235) are burned at conventional reactors and generate about 35 tons of spent nuclear fuel (waste).
- Thorium-based nuclear reactor (liquid fluoride thorium reactor): Since all natural thorium can be used as fuel, expensive fuel enrichment process is not needed. LFTR use only one ton of thorium per year for 1GW plant and produce 1ton of radioactive waste. Within 10years, the 83% of them are stable and can be sold and 17% of them go to geologic isolation for 300 years.
- According to MIT’s future of nuclear power 2009 analysis, most of the cost of nuclear electricity is actually the cost to construct the nuclear reactors (capital cost).
- The construction cost of thorium-fueled power plants is from five to seven times cheaper than that of traditional uranium reactors: Building a 1-gigawatt uranium plant today costs about $1. 1 billion. Building a 1-gigawatt thorium plant will cost only about $250 million or less, because meltdown concerns can be tossed out the window.
- Current operating costs, ignoring fuel costs, is a tenth of that of uranium reactor: While a 1-gigawatt uranium plant require about 500people and costs $50 million/year, thorium fueled reactor (liquid fluoride thorium reactor) costs $5 million/year.
- ThorCon liquid-fuel reactor, newly designed by Martingale Inc in USA, can generate electricity at 3cents/kWh which is cheaper than gas or coal.
3. Brief History
1) First Development
a. 1965~1968 an experimental molten salt reactor at Oak Ridge National Laboratory
- In the 1960s, uranium-based reactors were built to produce electricity, during that period, the U. S. Government built an experimental molten salt reactor using U-233 fuel, the fissile material created by bombarding thorium with neutrons.: The reactor, built at Oak Ridge National Laboratory, Operated critical for 15,000hours from 1965 to 1969
b. In 1968, the thorium-based reactor had been successfully developed and tested.
- Novel laureate and discoverer of plutonium, Glenn Seabory Publicly announced to the Atomic Energy Commission of which he was chairman, that the thorium-based reactor had been successfully developed and tested.
Policy of Nixon era : In 1973 US Government had made the decision to kill all of thorium research.
- Government scientists in the 1960’s developed a smaller and potentially safer form of nuclear power using cheap and abundant fuel, only to have the program mothballed and kept secret for decades.
- All thorium related research, which had been ongoing for twenty years at Oak Ridge National Laboratory,was stopped: The reasons were that uranium breeder reactors were more efficient, the research was proven, and byproducts could be used to make nuclear weapons.
- For the benefit of military uses, the safe thorium based nuclear power was sacrificed
- Carlo Rubbia, Italian Particle Physicist, generated 1MW of Electricity using proton cyclotron at the Paul Scherer Institute (PSI) in Zurich.
b. In 2013 Feasibility Testing of the thorium as a nuclear fuel
- In 2013, private norwegian company, Thor Energy began to produce energy at Halden test reactor in Norway using thorium as nuclear fuel: This test provide unique information necessary for qualifying this new fuel material for commercial use in current reactors.
b. Bill Thesling ,the Cleveland-based Energy from Thorium Foundation CEO
- Safety advantage over today’s high pressure reactors: In the thorium molten-salt reactor, thorium dissolved in a high temperature solutions of fluoride salts. It can't melt down because it’s already molten, so the concept of a meltdown is not even at play.
e. Professor Bob Cywinski, University of Huddersfield
- We need nuclear energy, nuclear power helps to combat climate change, emitting a tiny fraction of the carbon produced by fossil fuels. Misgivings over safety and the waste produced by conventional uranium-fuelled nuclear reactor can be addressed by the use of thorium.
- Jiang Mianheng, son of former leader Jiang Zemin visited the Oak Ridge labs and obtained the designs after reading an article in the American Scientist two years ago(2011) extolling thorium. He concluded that a molten salt reactor may answer for China's energy shortage and national security concern. He is spearheading a project for China’s National Academy of Science with a start-up budget of $350m. Over 140 PhD scientists have been working full-time on thorium power at the Shanghai Institute of Nuclear and Applied Physic.
- In 2014 China Government declared “War on Pollution” and decided to concentrate on developing thorium nuclear powers: The Chinese Academy of Science set up an advanced research centre in Shanghai in January 2014 with the aim of developing the world’s first industrial reactor using thorium molten-salt technology. A team of scientists in Shanghai had originally been given 25 years to try to develop the world’s first nuclear plant using thorium as a fuel. In March 2014, China Government reduced the original goal of creating a working reactor from 25years down to 10 by 2024 as China Government’s interest was changed from solving energy shortage to the smog crisis.
b. India: The leader in thorium reactor development. World’s first thorium reactor Designed.
- India refused to ratify the Nuclear Non-Proliferation Treaty (NPT) and excluded from trade in nuclear plant and material for 30years by Nuclear Suppliers Group (NSG). While India's uranium resources are limited due to trade bans, India has huge reserves of thorium.
- World's first thorium based nuclear reactor designed: In February 2014, the first look of design and prototype of the advanced heavy water reactor(AHWR) presented and slated for operation in 2016. Because of its inherent safety, researchers expect that thorium based nuclear reactors could be set up within populated cities like Mumbai. Dr. Sinha, chairman of Atomic Energy Commission predict that, the first megawatt of electricity would be generated within 7~8 years.
- From 2009 researchers at the Belgian nuclear research centre, SCK-CEN and EU have been designing for constructing the multi-purpose hybrid Research Reactor MYRRHA consists of a proton accelerator and reactor.
- According to a SCK-CEN schedule, construction could start in 2022, with commissioning the following year, and MYRRHA entering full operation by 2025.
- MYRRHA is now conceived as a flexible irradiation facility, able to work as an accelerator driven (subcritical mode) and in critical mode
- Using $250million in federal research funds to revive ORNL (Oak Ridge National Laboratory) research.
- U.S.Department of Energy is collaborating with Oak Ridge National Laboratory on molten salt reactor using molten fluoride salts as primary coolant and thorium as nuclear fuel
- Collaborating with China on thorium-based nuclear power designs using molten-salt reactor
- Bill Gates sees nuclear energy as a potential solution to lowering carbon-dioxide emissions around the world, and he has spent the past decade funding new ways to produce the energy in a safe, affordable way.
…About 10 years ago, Gates cofounded a company called TerraPower to build new kinds of nuclear reactors.
…The company is developing a new reactor that uses molten chloride instead of water as a coolant.
…Following a US Department of Energy investment worth $40 millionand a partnership with energy provider Southern Company, TerraPower plans on opening a new laboratory next year. Gates' company wants to develop a molten-chloride prototype by 2030, and the laboratory will be used to test reactor materials in the meantime.
…John Gilleland, the company's chief technology officer, told Business Insider that molten chloride designs are the "ultimate green reactor."
- Over the last several years, there has been a growing consensus among climate scientists that nuclear energy is critical for mitigating the worst effects of global warming. States are shifting from Renewable Energy Mandates to technology neutral Clean Energy Standards that include nuclear energy.
…Many new nuclear start-up companies have emerged in the United States, China and Canada, especially those designing small modular reactors (SMRs).
…One such reactor, ThorCon takes a different tack on manufacturing. It would be completely manufactured in 150 to 500 ton blocks in a shipyard, assembled, then towed to the site, producing order of magnitude improvements in productivity, quality control, and build time.
…ThorCon requires no new technology. ThorCon is a straightforward scale-up of the successful United States Oak Ridge National Laboratory Molten Salt Reactor Experiment (MSRE). A full-scale 500 MW ThorCon prototype can be operating under test within four years.
…ThorCon can produce clean, reliable, CO2-free electricity at 3 cents per kilowatt-hour — cheaper than coal
- Indonesia’s state company PT PAL Indonesia signed an agreement with nuclear power firm Thorcon International Pte Ltd to conduct development study and construction of a 500 mega watt and $1.2billion reactor, PAL Indonesia said.
…The thorium molten salt power plant is currently designed to be 174x66 meters floating facility which PAL said is expected to be built by Daewoo Shipyard & Marine Engineering in South Korea.
…PAL Indonesia, which produces warships and commercial vessels, will build the reactor and supporting components designed by Thorcon.
…Thorcon is working with Indonesia and could have its first 1 GW commercial unit in 4-6 years. ThorCon is a liquid-fuel fission power plant, under development in the US, to be built in a far-east shipyard, then floated to Indonesia, with testing starting in 2023-2025.
- Japan's International Institute for Advanced Studies(JIAS) is researching molten salt reactors that use liquid fuel.
- MYRRHA project: Collaborating with EU
- The UK is playing a key role in an international project to develop a new type of nuclear power station.
- Integral Inherently Safe Light Water Reactor (I2S-LWR) Project : To design I2S-LWR, cambridge team is considering the project not just from the perspective of fundamental nuclear reactor physics but also focusing on achieving high fuel-to-power conversion efficiency and cost effectiveness.
- SAMOFAR(Safety Assessment of the Molten Salt Fast Reactor) Project
- TU-Delft presented and officially announced a European Thorium MSR Project, SAMOFAR due to start in August 2015
- SAMOFAR Consortium consists of 11 participants from both science and industry
- The grand objective of SAMOFAR is to prove the innovative safety concepts of the MSFR by advanced experimental and numerical techniques, to deliver a breakthrough in nuclear safety and optimal waste management.
- The SAMOFAR project focuses on the MSR as a "self-breeder", producing its own fuel from cheap and abundant thorium without generating a surplus of proliferation sensitive fissile material, like all other reactors in the world do.
- Samofar is focused on fast reactors, which are more efficient than conventional light-water reactors and can breed fissile elements from nuclear waste.
- The researchers will build experimental laboratory facilities—not, at least for the next few years, an actual working reactor—to test the geometry of the freeze plug, the coatings of vessel and pipe materials, the behavior of the liquid fuel during circulation and draining, and other key safety metrics.
- In 2013, President Park and Bill Gates discussed about energy innovation. Bill Gates called for Korea’s attention in developing the next-generation nuclear reactor in order to efficiently deal with public safety concerns, nuclear waste and malfunctions.
1) Energy – Agrophotovoltaics :Combining Photosynthesis & Photovoltaics
- A convergence system that can produce electricity by building up solar panels on existing farmland, while preserving farmland in one piece and sustain the harvest of crops as well.
- The system is believed to contribute to increasing income of farming households, importantly along with expanding the spread of new·renewable energy.
2) Light saturation point
- [Light saturation point (LSP)]: Each plant has a certain amount of light it needs to grow well. Sunlight over that amount is not needed.
- Any light past the Light saturation point (LSP) causes harm.
- Agrophotovoltaics know as agricultural solar sharing uses the extra sun energy that would otherwise to wastes or be harmful to the plants.
3) Energy Generation + Crop Harvest
By way of installing solar panels at such a height as not to obstruct the operation or transportation of agricultural machineries and placing them with such an enough spacing as to ensure sufficient sunshine for the crops to grow, the crop yield shall be kept no less than those before the construction.
4) Significance: presenting new direction of new & renewable energy business
This is an eco-saving technology which enables to produce and sell the electricity at the same time as harvesting of crops, thereby contributing not only to the improvement of the incomes of farming households but also to the efficient utilization of scarce land all over the world.
2. Agrophotovoltaics & Agriculture
1)Food Crisis & Instability in agricultural work
- Food Crisis
…The growing global population, coupled with the shortage of arable land, could mean that we’re heading for a food crisis in the future.
...Farming is different from other jobs because it can be hard to predict production amounts.: The weather is greatly influencing crops, and crop yield is directly linked to livelihood. There is also the problem of not getting any income if the crops that were harvested couldn’t be sold
2) Benefits from Agrophotovoltaics (Solar sharing) system
A great way to solve the shortage of arable land and the problem of instability in agricultural work
- Increased land productivity
…The dual use of land for the harvesting of solar electricity and agriculture has been test and showed the land use efficiency of 160 percent in 2017 and 186 percent in 2018
- Improved water efficiency of land: positive results in using solar panels on farmland
...In 2018, experts from Oregon State’s College of Agricultural Sciences revealed the results of a study showing that solar modules could increase agricultural production on dry and unirrigated land.
...The soil beneath the panels had higher levels of moisture than the soil exposed directly to the sun.
...Reduced need for irrigation
- Stabilized and increased Profit
…Profit is further stabilized by adding income from energy produced and sold (or locally used) to income from agriculture.
…With this added income, it makes it easier to become established as a full-time farmer. Furthermore, by becoming a full-time farmer, more time can be used for making high quality crops.
-Prepare a good cultivation environment
...Key solution to reduce the need of time-consuming and labor cost and improve an uncomfortable labor environment
ex) installing an automatic fertilizer as part of the solar sharing frame, which could be programmed each season
ex) The solar panels overhead create shade as a thermal insulator for the laborers working with the crops making it a more bearable environment to work in.
- Making the farm completely energy-independent
...Farmers will no longer be surprised by unexpected power failures, since the energy captured from sunlight will be stored using batteries, making the farm completely energy-independent.
- Additional benefits
...Protection against damage caused by hail, drought and frost
-Over the past two years, the dual use of land for the harvesting of solar electricity and agriculture has been tested in the joint project of Fraunhofer ISE.
…On one-third of a hectare arable land near Lake Constance in Germany, photovoltaic modules with a total power output of 194 kilowatt are installed on a five-meter-high structure.
…The results from 2017 showed a land use efficiency of 160 percent, as confirmed by the project consortium.
…The performance of the agrophotovoltaic system in the very hot summer of 2018 greatly exceeded this value.: Based on the 2018 potato yield, the land use efficiency rose to 186 percent per hectare with the agrophotovoltaic system -by Stephan Schindele of Fraunhofer ISE
-Scientists of the University of Hohenheim collected data on the climatic conditions underneath the APV system and also from the neighboring reference field.
…The solar irradiation underneath the APV system was about 30 percent less than the reference field. In addition to the amount of solar irradiation, the APV system affects the distribution of precipitation and the soil temperature.
…In spring and summer, the soil temperature under the APV system was less than on the reference field; the air temperature was identical.
…In the hot, dry summer of 2018, the soil moisture in the wheat crop was higher than the reference field, while in the winter months, it was less.
→The shade under the semi-transparent solar modules enabled the plants to better endure the hot and dry conditions of 2018 -the agricultural scientist Andrea Ehmann
→This result shows the potential for APV in arid regions.
-The electricity production costs of an APV system is today competitive with a small PV rooftop system. Researchers anticipate further cost reductions due to economies of scale and learning effects.
…If the electricity is stored and used on site, as at the farm community Heggelbach, additional sources of income arise due to synergy effects.
…When politics allow, agrophotovoltaics can provide the answer to the “food or fuel” debate. From the technical point of view, farmers can harvest both.
…Through the dual use of arable land, the main task of food production is met. The additional solar electricity production contributes to the expansion of electric mobility and serves to protect the climate.
3. Agrophotovoltaics & Energy
1)Global Energy Solution
-Earth friendly energy
…Energy generation without carbon emissions
…Shade from the panels protects against overheating and global warming, also keeps the earth humid.
-Effective Energy: there is little sunlight wasted.
…Most crops need light to grow. However, plants don’t expend all the light they take in from the sun. Each plant has its own limit to how much sunlight it can take in, and if it goes over that limit it is wasted, or hurts the plant. Agrophtoboltaics (Solar sharing) is used to take in the sunlight that would otherwise go to waste or otherwise harm the plants and turns it into usable electricity.
…An effective way to produce sustainable energy without devastating the environment
…This system enables people to generate electricity on farmland, pasture land, water surfaces, roads, and anywhere people, animals, and plants are living.
…Even barren deserts can be changed into habitable lands where people can produce food and energy simultaneously.
2)Overcoming the problem of traditional PV power generation
-Agrivoltaic systems can help to overcome the problem of limited land resources, negating this disadvantage of PV power generation.
…Limitations related to the installation area are one disadvantage of traditional PV power generation: This is less important for households, where PV modules installed on rooftops can generate sufficient electricity, but industry requires a huge area for PV power plants to provide a sufficient and constant electricity supply.
3)Supplementation of agrivoltaic systems
-Battery backup systems
…The system cannot adequately function if sunlight is not available during the night or on cloudy days : Thus, it is difficult to rely on agrivoltaic systems as a main power source even if the total generation capacity is large enough to meet a country’s electricity demand.
…The key to solving this is to employ battery backup systems that can store electricity for use when sunlight is not available.
-PV Panel Recycling
…Although PV power generation itself does not cause pollution, the disposal of PV panels may have serious impacts on the environment. The impact could be particularly serious if agrivoltaic systems are adopted for large areas of farmland, resulting in huge volumes of PV panels requiring disposal.
…It is necessary to develop effective methods for recycling large volumes of PV panels while also promoting agrivoltaic systems.
4. World leading countries in solar sharing technology
-Solar power generation came to Japan in the year 1993.: For 20 years, one of the changes that has come about in the field of solar energy is Agricultural Solar Sharing (also known as agrophotovoltaics (APV) or agrivoltaics).
-In 2013, there was only about 100 developments. By the year 2017 there was about 1,300 developments.Currently the most solar sharing projects are in Chiba prefecture, with Shizuoka prefecture having the second most, and Gunma prefecture has the third most.
-Since 2016, the dual use of land for the harvesting of solar electricity and agriculture has been tested
-Integrated Photovoltaic Solutions presented at the EU PVSEC 2019 by Fraunhofer ISE
…Meeting Germany’s climate protection targets will require a significant expansion of photovoltaics.
…Integrating PV technology into building envelopes, vehicles and roads, as well as over agricultural fields and floating on water surfaces, capitalizes on surface areas with a tremendous potential for generating solar power.
…In Germany, building-integrated solar technologies and agrophotovoltaics alone can offer several hundred gigawatts of power.