MSR Benefits

Molten Salt Reactor Advantages

  • Molten Fuel - Fuel circulates through the reactor, fission products get removed, for over 99% fuel use (vs. LWR ~3%). No long-term radioactive waste.
  • Salt Cooled - Coolant far below boiling point, reactor operates at atmospheric pressure. Fuel dissolved in stable salt (no water), no loss of coolant accident possible. No need for high-pressure safety systems.
  • High Inherent Safety - No water, no high pressure, nothing that could propel radioactive materials into the environment. Thermal expansion/contraction of molten fuel salt strongly regulates fission rate; MSR is a very stable reactor. Simple safety systems work even if no electricity or operators.
  • Easy Construction and Siting - Low pressure operation, so no high-pressure safety systems. No water, so no steam containment building. Reactor factory assembled, with modern quality control, sensors and communication.
  • Lower Cost - Even with exotic materials, construction costs will be dramatically lower than LWR — factory construction, minimal manual on-site preparation. No long-term radioactive waste, so no long-term storage.
  • High Temperature Operation - Heat to generate electricity, desalinate water, produce CO2-neutral vehicle fuel, etc.
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LFTRs eliminate most of the expensive, complex (and therefore failure-prone) systems in water-cooled reactors.

Molten salts are superior coolants so heat exchangers and pumps are smaller and easy to fabricate.

Simpler design and smaller size mean LFTRs can be produced in a factory and delivered, reducing construction cost and time, while increasing manufacturing reliability.

Assembly line production of a reactor would be comparable in complexity and quality control to building large aircraft.

Using modern design for the LFTR core, a reactor with a 6.6m long by 0.7m wide core, and a meter thick thorium-conversion blanket, generates 220MW electricity “in a simple to manufacture design that can fit within a tractor trailer for transport”. D. LeBlanc / Nuclear Engineering and Design 240 (2010)

Business economists observe that commercialization of any technology leads to lower costs as the number of units increases and the experience curve delivers benefits in work specialization, refined production processes, product standardization and efficient product redesign. Given the diminished scale of LFTRs, it seems reasonable to project that reactors of 100 megawatts can be factory produced for a cost of around $200 million. Hargraves, American Scientist Vol 98, July 2010

Production Requirements

Once we have assembly line production, a 100 MegaWatt LFTR would cost around $200 Million, so the total cost of producing power would be cheaper than coal. Boeing makes a $200 Million dollar product per day. Robert Hargraves – Aim High! @ TEAC3

“Boeing produces one $200 million plane per day in massive production lines that could be a model for mass production of liquid fluoride thorium reactors. Centralized mass production offers the advantages of specialization among workers, product standardization, and optimization of quality control, as inspections can be conducted by highly trained workers using installed, specialized equipment.” Hargraves, American Scientist Vol 98, July 2010

LFTRs can be 1-5 MW up to 1000MW or larger, to fit the site needs.

Site footprint:
A light water reactor would need 200,000 to 300,000 square feet, surrounded by a low-density population zone.
A LFTR would need 2,000 to 3,000 square feet, with no need for a buffer zone. Thor-Facts

Production details for installing a LFTR 10m underground (to prevent most terrorist attacks and avoid most natural disasters) are included in Moir and Teller, 2005

A Manhattan Project level of focus would produce operating LFTRs within 2-3 years and production in 5 years. Skunk works level of focus would have a prototype in 5 yrs, production in 10yrs. Cost to have LFTRs ready to be mass produced would be comparable to designing and certifying a new single PWR plant. Energy From Thorium: A Nuclear Waste Burning Liquid Salt Thorium Reactor

FLiBe Energy plans to have a LFTR operational by 2015.

Most LFTR designs (like the MSRE) use thermal neutrons (lower energy), but fast-spectrum molten salt reactor designs also work well; similar liquid-fuel, atmospheric pressures and chemically stable salt coolants. See Fast Spectrum Molten Salt Reactor Options, Oak Ridge Nat’l Labs

Liquid fluoride solutions are familiar chemistry. Millions of metric tons of liquid fluoride salts circulate through hundreds of aluminum chemical plants daily, and all uranium used in today’s reactors has to pass in and out of a fluoride form in order to be enriched. The LFTR technology is in many ways a straightforward extension of contemporary nuclear chemical engineering. American Scientist volume 98 – Hargraves, 2010

“The containment wall thickness and consequent capital costs for FS-MSRs will be lower than those for other reactor types because mechanisms to generate pressure or explosive chemical mixtures within containment are lacking. The containment walls are only required to contain a low-pressure internal environment and endure when subjected to external seismic and impact stressors. Halide salts are chemically inert, so they do not have exothermic reactions with the environment (oxygen, water) as would hot sodium or hot zirconium. With a greater than 500°C margin to boiling, the halide salts also do not have a credible route to pressurizing containment as would a water-cooled reactor. FS-MSRs also do not have any hydrogenous material within containment; thus they cannot generate hydrogen.” Fast Spectrum Molten Salt Reactor Options, Oak Ridge National Labs, July 2011

“FS-MSRs will require more expensive structural materials than LWRs because of their higher reactor temperatures and fast neutron flux tolerance requirement. However, because of the lower pressure, smaller amounts of the materials will be required. Overall, the material-expense-balance economics are as yet unknown. FS-MSRs will also require more expensive components and instruments because of both the higher temperatures and the requirement to accommodate remote maintenance.” Fast Spectrum Molten Salt Reactor Options, Oak Ridge National Labs, July 2011

About Hastelloy: “Good resistance to aging and embrittlement and good fabricability. It has excellent resistance to hot fluoride salts in the temperature range of 1300°F to 1600°F (705°C-870°C).” and “In tests of over two years duration, corrosion attack on HASTELLOY N alloy in molten fluoride salts at temperatures up to 1300°F (704°C), was less than one mil per year. It is expected that alloy N will be most useful in environments involving fluorides at high temperatures… HASTELLOY N alloy has good oxidation resistance in air. It shows promise for continuous operations at temperatures up to 1800°F (982°C).”HASTELLOY ® N alloy

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