PART 1: Liquid Fuel Nuclear Reactors introduced the history and technology of liquid fuel nuclear reactors – the path not taken as the world followed Rickover’s forceful choice of solid fuel reactors.

PART 2: Energy Cost Innovation described the opportunities for substantial cost reductions and presented the specific attributes of the molten salt reactor that lead to lower costs for energy.

Coal and prosperity

Worldwide, coal is the largest and fastest growing source for electric power, growing 50% in a decade. The 1,400 GWe of world coal power capacity is literally planned to double. The 2009 update of MIT’s Future of Nuclear Power shows new coal plants cost $2.30/watt, contributing about 2.3 cents/kWh to power costs [at 8% cost of capital, 40 year lifetime, 90% capacity factor]. Inexpensive US coal at $45 per ton contributes $0.018/kWh to electrical energy costs. Including operations costs, coal power costing about 5.6 cents/kWh is generally the least expensive energy source worldwide.

Affordable electric power is crucial to the developing world’s economies and their peoples’ prosperity. Peabody Coal CEO Gregory Boyce states the case for coal, “…there are 3.6 billion people in the world - more than half the global population - who lack adequate energy access. And another 2 billion will require power as the world population grows in the next two decades. …each year, we lose more than 1.5 million people to the effects of energy poverty.” Boyce called for recalibrating priorities to: eliminate energy poverty as priority one; create energy access for all by 2050; advance all energy forms for long-term access, recognizing coal is the only fuel that can meet the world's rising energy demand (italics added).

The World Bank seems to agree, lending $5.3 billion for 29 coal plants, but at the same time decrying increasing CO2 emissions they say may raise global temperatures 4°C. Economics trumps politics. In a global economy, the most economical power source will dominate. The failures of United Nations Framework Convention on Climate Change meetings in Kyoto, Copenhagen, Tianjin, Cancun, Bangkok, Bonn, Panama, and Durban testify to the power of economics and the importance of low-cost energy.

Global warming

Airborne coal soot causes 13,000 annual deaths in the US and 400,000 in China. Burning coal for power is the largest source of atmospheric CO2, which drives global warming, which threatens irreversible climate damage, ending glacial water flows needed to sustain food production for hundreds of millions of people, and shrinking the polar cold water regions of the ocean where algae start the ocean food chain. Atmospheric CO2 dissolving into the ocean acidifies it, killing corals and stressing ocean life. Demand for biofuels increases destruction of CO2 absorbing forests and jungles. The World Bank predicts food shortages will be among the first consequences within just two decades, along with damage to cities from fiercer storms and migration as people try to escape the effects. In sub-Saharan Africa, increasing droughts and excessive heat are likely to mean that within about 20 years the staple crop maize will no longer thrive in about 40% of current farmland. 

Ending coal CO2 emissions

Boeing-like factory production of one DMSR of 100 MWe size per day could phase out existing coal-burning power plants worldwide in 38 years, ending 10 billion tons of CO2 emissions from coal plants now supplying 1,400 GW of electric power. Energy cheaper than coal is crucial to reducing CO2 emissions.

Figure 8. Replacing coal plants with one 100 MWe DMSR per day zeros 10 GT of annual CO2 emissions in 38 years

Figure 8. Replacing coal plants with one 100 MWe DMSR per day zeros 10 GT of annual CO2 emissions in 38 years.

Ending energy poverty

The world population growing from 6.7 to 9 billion will increase resource competition, exacerbating environment stress. Yet the OECD nations, with adequate energy supplies, have birthrates lower than needed for population replacement. In developing nations, electricity can liberate women from chores of fetching water, cleaning, providing food, and raising children. Women with freed time can become educated, obtain jobs, gain independence, and make reproductive choices.

Figure 9. When economic well-being measured by the gross domestic product exceeds a threshold, birthrate drops sharply.

Figure 9. When economic well-being measured by the gross domestic product exceeds a threshold, birthrate drops sharply. (Data from CIA World Factbook.)

Nations with GDP per capita over $7,500 have sustainable birthrates. Electricity for water, sanitation, lighting, cooking, refrigeration, communications, health care, and industry contributes to economic development and improved personal incomes. Those nations with per capita electricity of 2,000 kWh/year (an average power of 230 W, 1/6 US use) do achieve GDP of $7,500 per capita, which leads to sustainable birthrates.

Producing CO2-neutral carbonaceous synfuels

Petroleum is the second largest source of world CO2 emissions, after coal. Cheap oil has been an important driver of world GDP. Concerns over peak oil have diminished with techniques for extraction of tight oil, but rising prices and decreasing EROI are implicated in GDP stagnation. High priced oil creates an economic opportunity for synthetic liquid fuels.

Synthesizing hydrocarbon fuels requires a source of hydrogen and a source of carbon. Nuclear heat and electricity can power dissociation of hydrogen from water. At a temperature of 950°C, the sulfur-iodine process works at a chemical/thermal conversion efficiency approaching 50%. The 43% efficient copper-chloride process can operate at 530°C, a temperature compatible with currently certified nuclear structural materials to be used in near-term DMSRs.

Potentially the carbon source can be CO2 that makes up about 0.037% of the atmosphere. Historically direct air capture has been criticized as uneconomic, but this can change with the availability of low-cost, high-temperature nuclear heat. Jeffrey Martin and William Kubic observed that alkaline lakes absorb about 30 times the CO2 of similar size fields of switchgrass. Their project Green Freedom conceived of trays of potassium carbonate solution exposed to the airflow within nuclear plant cooling towers. The potassium carbonate readily absorbs CO2 [by CO2 + K2CO3  + H2O à 2 KHCO3] creating potassium bicarbonate. The CO2 would be electro-chemically removed, requiring about 410 kJ/mole-CO2 of electric energy and 100 kJ/mole-CO2 of thermal energy. The chemical manufacturing processes for conversion of CO2 and hydrogen to methanol are proven; ExxonMobil has a process for converting methanol to gasoline. The complete facility could produce 17,000 barrels per day of gasoline at an estimated consumer cost of $5/gallon (2007), requiring an investment of approximately $5 billion. The fuel cycle would be carbon neutral, because just as much CO2 would be put into the atmosphere by burning synfuels as removed by air capture.

Nobel laureate George Olah advocates methanol fuel per se in The Methanol Economy because it is largely compatible with the existing gasoline infrastructure. Methanol has been used for decades to power race cars at the Indianapolis-500. Although it has about half the energy density of gasoline, methanol can be used in flex-fuel vehicles or  modified engines in ordinary vehicles.

Figure 10. CO2 is absorbed by lye [KOH] changed to lime [Ca(OH)2] heated to release CO2

Figure 10. CO2 is absorbed by lye [KOH] changed to lime [Ca(OH)2] heated to release CO2.


Jim Holm has an ambitious Skyscrubber concept to capture even more CO2, using Carbon Engineering’s process with high temperature nuclear heat. He proposes replacing the world’s 1200 largest coal plants, eliminating 10 Gt/y of CO2 emissions, and also capturing 2 Gt/y of CO2. His concept uses the high-temperature, helium-gas-cooled TRISO-fuel reactor which is closer to deployment than MSR, but MSR may be economically essential to replace the coal plants because MSRs are predicted to be lower cost than TRISO reactors.

Biomass carbon sources

Plants absorb carbon from air. Biomass energy technology strives to harvest the combustion energy stored in plants, but they can be alternatively used as a carbon source for synfuels. Biomass and hydrogen can be combined with nuclear heat to manufacture synfuels such as diesel more efficiently than does cellulosic ethanol technology.

Biomass can be processed in a heated, entrained-flow chemical reactor to create liquid fuels. The required thermal energy can be supplied from an MSR, adding hydrogen from water dissociation, and raising the temperature of the oxygen-free production process to approximately 1000-1200°C using an electricity-powered plasma arc. The role of the biomass is not so much to provide energy but to contribute the carbon that is combined with hydrogen and MSR energy to synthesize the biofuel.

By avoiding oxidation of the biomass, the synfuel mass yield is 1 tonne of diesel per 1.7 tonnes of biomass. This is 3.3 times that of anticipated cellulosic ethanol processes such as enzymatic fermentation or gasification. This reduces land use requirements for biomass production by 70%, reducing competition with land for food crops. Estimated costs for diesel fuel production in this manner are $4 per gallon.

The US consumes about 7 billion barrels of petroleum products per year. Dry biomass growth is about 6 tonnes/ha/yr, so to supply all US petroleum substitutes this way would require 160 million hectares for biomass crops. Forestland and farmland area in the US totals about 670 million hectares, so meeting US fuels needs this way is barely conceivable, if fuel use is reduced. Other potential carbon sources include cattle dung of 2.5 Gt/year, but collection costs are high. City sewers efficiently collect biomass at a rate of 100 grams per person per day.

No such biomass refineries are in production, and there is considerable chemical engineering development to be accomplished before constructing such billion-dollar plants. The major oil companies have the expertise to develop them. Petroleum’s high energy density and a century of engineering experience in its use have made it essential to the world economy. It could take another century to replace it with synthetic carbonaceous fuels.


The US uses 20 million tons of ammonia and ammonia fertilizer products annually. Energy for production of ammonia uses 1-2% of all world energy. Over 80% of ammonia is used for fertilizers that are responsible for food production sustaining 1/3 of the world population. Ammonia fertilizers were a component of the 20th century Green Revolution credited with saving over one billion people from starvation. Today ammonia is principally produced from natural gas, releasing CO2. World food production is highly dependent on fossil fuels.

Figure 11. Marangoni Toyota G86 Eco Explorer runs on ammonia fuel.

Figure 11. Marangoni Toyota G86 Eco Explorer runs on ammonia fuel. 

Ammonia, NH3, may be used as a fuel in internal combustion engines. With hydrogen from dissociation of water and nitrogen from air, ammonia can be produced without relying on carbon sources. Here’s a great video explanation by 12-year-old Katie. Like propane, liquid ammonia can be transported in tanks pressurized to about 13 atmospheres. It has been used as fuel for the X-15 rocket plant, WW II busses in Belgium, trucks and cars.

The NH3 Fuel Association advocates ammonia as a fuel for internal combustion engines. Today engineers are improving spark-ignited internal-combustion engines and diesel engines fueled with ammonia or ammonia with additives such as biodiesel, ethanol, hydrogen, cetane, or gasoline. Sturman Industries is developing an ammonia fueled hydraulic engine – no crank, no cam, no carbon.  Direct ammonia fuel cells can convert ammonia and air’s oxygen directly to electric power, without the need to thermally crack NH3 to release hydrogen.

Figure 12. Ammonia can generate electricity in fuel cells

Figure 12. Ammonia can generate electricity in fuel cells.

Solid state ammonia synthesis

Today the Haber-Bosch ammonia production process annually manufactures 500 million tons of ammonia from natural gas, water, air, and electricity. This process alone accounts for 3-5% of world natural gas consumption. For each tonne of ammonia produced, stripping carbon from CH4 releases 1.8 tonnes of CO2 to the atmosphere – about 10% of world coal plant emissions.

The company NHThree has designed a state ammonia synthesis (SSAS) plant fed by air, water, and electricity. Nitrogen is obtained from an air separation unit (ASU). There is never any separated explosive hydrogen gas. SSAS works like a solid oxide fuel cell, but in reverse, with a proton conducting ceramic membrane. The ceramic membranes are tubes, and the SSAS can be scaled up by using more tubes. In addition to electricity, an MSR can provide the 650°C steam heat for the SSAS cells.

Figure 13. Solid state ammonia synthesis: 6 H2O + 2 N2 → 3 O2 + 4 NH3

Figure 13. Solid state ammonia synthesis: 6 H2O + 2 N2 à 3 O2 + 4 NH3

With factory reactor production, MSR electric power is projected to cost $0.03/kWh, leading to ammonia costs of about $200 per tonne. Ammonia from natural gas today costs about $600/tonne. This new SSAS process has been demonstrated in the laboratory, but it requires chemical engineering development to generate ammonia in commercial quantities.

Cost of ammonia fuel

 The heat of combustion is the thermal energy that would be released in an internal combustion engine. The crude oil source energy cost of $4/gallon gasoline is about $2.67; other costs: taxes, refining, and distribution, only add $1.33. Assuming other costs stay the same, energy-equivalent ammonia fuel could sell for 2/3 the cost of gasoline.


Heat of combustion

Energy source price

Fuel energy cost


  22 MJ/kg




132 MJ/gal



Ammonia safety

Ammonia is the second most common industrial chemical. In the US ammonia is distributed by a 3,000 mile network of pipelines, principally for agricultural use. In a vehicle, ammonia would be liquid in tanks pressurized to 200 psi, similar to propane (177 psi). Compare this to tanks needed for compressed natural gas (3000 psi) or hydrogen (5000 psi). In an accident, spill, or leak ammonia dissipates rapidly because it is lighter than air. Its pungent odor is alerting. Ammonia is difficult to ignite, with an ignition temperature of 650°C. Unlike gasoline an ammonia fire can be extinguished with plain water.

Inhaling an ammonia concentration of one half percent for a half hour has a 50% fatality risk. Inhalation of 500 ppm is dangerous to health. Chronic exposures of 25 ppm are not cumulatively dangerous as humans and other mammals naturally excrete NH3 in the urea cycle, but ammonia is toxic to fish. The hazards of ammonia are different but equivalent to those of gasoline. Ammonia is toxic and gasoline is explosive. A 2009 Iowa State University analysis concludes

“In summary, the hazards and risks associated with the truck transport, storage, and dispensing of refrigerated anhydrous ammonia are similar to those of gasoline and LPG. The design and siting of the automotive fueling stations should result in public risk levels that are acceptable by international risk standards. Previous experience with hazardous material transportation systems of this nature and projects of this scale would indicate that the public risk levels associated with the use of gasoline, anhydrous ammonia, and LPG as an automotive fuel will be acceptable.”

In summary, nuclear ammonia is a suitable vehicle fuel. It emits no CO2 when burned. Its production can be CO2 free. It would require larger, stronger vehicle fuel tanks. The raw materials are air, water, and external low-cost energy from a MSR. Unlike carbonaceous synfuels, there is no expense to collect carbon from sources such as air or biomass. The economics of replacing gasoline with ammonia this way depend upon the energy-cost-innovative technology of the MSR.

Driving world GDP growth

World government debt exceeds $50 trillion, having doubled in 10 years. The public debt of the G7 advanced economies exceeds 100% of GDP, probably contributing to low economic growth. In 2012 US GDP grew at 2.5% while US debt grew at 8%.  US GDP only grew at a 1.8% annual rate in 1st quarter 2013.

The IMF suggests oil prices might double in a decade, diminishing GDP growth. Gail Tverberg at the Oil Drum illustrates how oil and GDP are related.



Figure 14. Energy and GDP are linked.

Oil prices are rising, partly because of diminishing EROI (energy return on invested energy). Chris Nelder tells us that a 60% drop in EROI from 25 to 10 increased oil prices 150%, and that a future drop from 5 to 2 would likewise increase prices to $240/bbl. Overall EROI for oil has dropped from 100 to about 10, and EROI for oil sands is near 5. EROI for corn ethanol is near 1.

Figure 15. Cheap energy ends as decreasing EROI cuts net energy delivered

Figure 15. Cheap energy ends as decreasing EROI cuts net energy delivered.

Economists from Solow to Ayres and Warr model GDP as a function of capital, labor, and energy. The oil sector represents about 4% of GDP, and the whole energy sector about 8%, but the impact of energy is greater than this suggests. Ayres points out there is no short term substitute for energy, and the output elasticity of energy services must be significantly greater than the cost share. Tverberg calculated a 0.4% increase in oil supply relates to a 2.2% increase in GDP, a 5-to-1 effect.

Ayres and Warr key on the concept of the energy that does useful work – electric power and mobile power – rather than primary, thermal energy. US aggregate work/thermal efficiency has improved from 2.48% in 1900 to 13.17% in 2006. Electric power generation efficiency rose from 8% in 1920 to 30% in 1960. A modern ultrasupercritical pulverized coal plant can achieve 47% and a new combined cycle natural gas turbine 60%, but this source of useful work, efficiency improvement, is running out.

Ayres and Warr and Hamilton point out that oil price rises are correlated with recessions, reported by the Wall Street Journal and Oil Drum.

Figure 16. Oil price rises have led recessions

Figure 16. Oil price rises have led recessions.

The implication is that diminishing EROI, efficiency saturation, and rising energy prices depress GDP. Cheap energy is no longer the source of economic growth that can solve the fiscal crisis. Energy cost innovation with liquid fuel nuclear reactors may provide that GDP growth opportunity.

Molten salt reactor development

Heightened public concerns about nuclear waste, global CO2 emissions, and nuclear power cost have led scientists and engineers to revisit the liquid fuel technologies bypassed in the 1970s. Lawrence Livermore scientist Ralph Moir and Edward Teller, a Manhattan Project veteran and developer of the hydrogen bomb, called for the construction of a small prototype MSR to launch such an energy project in 2005. Oak Ridge had meticulously documented its research, which was scanned and posted on the web in 2006 by then graduate student Kirk Sorensen.

Figure 17. Underground MSR proposed by Edward Teller and Ralph Moir.

Figure 17. Underground MSR proposed by Edward Teller and Ralph Moir.

France supports theoretical work by two dozen scientists at Grenoble and elsewhere. The Czech Republic supports laboratory research in fuel processing at Rez, near Prague. Design for the FUJI molten salt reactor continues in Japan. Russia is modeling and testing components of a molten salt reactor designed to consume plutonium and actinides from LWR spent fuel. MSR studies continue in Canada and the Netherlands. US R&D funding has been relatively insignificant, except for related studies of solid fuel, molten-salt-cooled reactors at UC Berkeley, MIT, U Wisconsin, and ORNL.

Startup ventures in Alabama, Ontario, Florida, and South Africa are actively designing MSRs, raising capital, and seeking a host nation with performance-based regulations. TerraPower is studying liquid fuel reactors as well as developing its traveling wave reactor.

Developing MSRs requires high temperature materials for the reactor vessel, heat exchangers, and piping; and chemistry for uranium and fission product separation. The authors estimate that with national laboratory support, a prototype could be operational in 5 years for approximately $1 billion. It may take an additional 5 years of industry participation to achieve capabilities for mass production.


The US Nuclear Regulatory Commission is not capable of licensing and regulating liquid fuel nuclear reactor technology. Its rules and procedures are specific to existing LWR power plant technologies. To illustrate, TerraPower has been driven from Washington state to China to gain permission to build its TWR. In 2007 NRC had proposed developing risk-informed, performance-based, technology-neutral regulations but the administration and Congress have not authorized nor funded this.

The biggest obstacle to advanced nuclear power technology is public ignorance and unwarranted fear of low-level ionizing radiation. Tens of thousands of people were unnecessarily evacuated from areas surrounding Fukushima, and many died from the stress. The World Health Organization and the United Nations reported that no one died from radiation nor will ill health effects be observed. Still incorporated into regulations, the obsolete linear no-threshold model (LNT) ignores direct evidence that low levels of radiation stimulate cellular responses that repair any damage from radiation. The existing ALARA (as low as reasonably achievable) guideline encourages ever more costly, unnecessary radiation protection. Nuclear power opponents use this fallacy that any radiation is dangerous to ratchet up costs to uneconomic levels. ICRP, EPA and NRC regulations should set threshold exposure limits in the same manner as for other potential health hazards. Governments must exhibit leadership in establishing new safety regulations that are based on observed health effects; then governments can unleash this cost-innovative technology.


Can liquid fuel reactor technology really be cheaper than coal? Yes! Moir’s analysis of ORNL’s design documents MSR energy cheaper than coal. One non-public venture has estimated its MSR costs leading to electricity costing 3-5 cents/kWh. Costs do depend upon goals. Opponents of nuclear power will attempt to raise costs by adding unnecessary requirements. The goal of energy cheaper than coal must be prioritized at every step of design and development. The potential global impacts on climate change, energy poverty, fuel costs, and economic growth can keep the focus on cost innovation.

The world faces a climate crisis from ever increasing CO2 emissions from burning fossil fuels. Developing nations, especially, strive to end energy poverty and improve the prosperity of their people. The new world economic order means nations will adopt the lowest cost energy sources. Only cost-innovative, zero-carbon, nuclear power can undersell coal, oil, and natural gas power sources.


Robert Hargraves, author of the book THORIUM: energy cheaper than coal, teaches energy policy at the Institute for Lifelong Education at Dartmouth College. He received his Ph.D. in physics from Brown University.

Ralph Moir has published ten papers on molten salt reactors during his career at Lawrence Livermore National Laboratory. He received his Sc.D. in nuclear engineering from the Massachusetts Institute of Technology.