Molten salt reactors, however, are fundamentally different from conventional nuclear reactors. MSRs use a liquid fuel, whereas conventional reactors use a solid fuel – and MSRs operate at atmospheric pressure, whereas conventional reactors are highly pressurized. “The ability to operate at atmospheric pressure brings many engineering advantages,” said Mr. MacDiarmid. “The IMSR will be a much less expensive machine to build and operate, period.” ___ Terrestrial Energy MSR
Humans need cheap, plentiful, reliable, high-quality heat & electricity if they are to build an abundant and expansive future for themselves and their progeny.
New nuclear reactor designs that are safer, more reliable, more affordable to build and operate, and more efficient, are in the works in Canada and the UK. Not only are these molten salt reactors (MSRs) more affordable, safer, and more efficient — but they burn away nuclear waste!
The Advantage of MSRs
The molten salt technology had several distinct advantages over the light water reactors:
Operating Pressure: The first inherent virtue was the fact that MSRs operate at a much higher temperature without the need for high pressure. While failure of the primary system at a PWR can result in a highly pressurized release of radioactive material, MSRs operate at atmospheric pressure. A failure would therefore not lead to dispersion of radioactive materials such as was seen at Chernobyl.
Risk of Meltdown: Since an MSR is already operating in a liquid form with molten salts, by definition it cannot have a meltdown. A rupture of a pipe or the containment vessel would simply result in solidification of the molten salts with the radioactive elements remaining inert in a crystallized form.
Overall Stability: If the MSR creates too much heat, the molten salts expand into the surrounding pipes. In such a case, the chain reactions are reduced and the heat levels fall.
Passive Safety Systems: Oak Ridge created a simple back-up safety system in the event of failure, in the form of a ‘freeze plug,’ a salt plug kept cool by a fan. If the system loses power, the salt plug melts and the liquid salt flows into a geometrically designed tank where fission ceases to occur. This is significant, particularly when compared to the systems utilized at today’s light water reactors such as Fukushima. Although the Japanese facilities shut down immediately after the initial earthquake, the resulting tsunami overwhelmed the back-up electrical generators and battery systems necessary to keep the system cool and stable. The reactors overheated, resulting in a reaction that released hydrogen which accumulated in the containment. This ultimately led to the explosions that ruptured the containment.
Lower Proliferation Risk:
Another advantage of the molten salt reactor is that it can run on thorium, making it unsuitable for weapons use and therefore possessing non-proliferation characteristics. Partly for that reason, in 2002 the Generation IV International Forum (GIF – led by the European Atomic Energy Community) anointed the MSR technology as one of six most promising for future development. __ Peter Detwiler
More on molten salt reactors, an old technology that wants to become new again:
Conventional reactors use solid uranium fuel, bathed in either heavy water or ordinary water.
The salt reactors, or IMSRs, dissolve low enriched uranium in solution of a salt such as sodium fluoride.
A moderator is added to control the reaction – in this case, it’s graphite carbon – and the process begins, releasing heat as the atoms split.
Most commercial reactors in Canada today are big beasts, used to power electric generators connected to the main power grid.
Terrestrial is looking at smaller scale reactors that might well be used by companies to heat steam for industrial processes — perhaps in remote locations like the oil sands, or mining sites. Or they could power off-grid generators.
One advantage of the molten salt reactors is that they use uranium more completely that current reactors, said Irish.
They consume the elements that are among the longest-lived and most troublesome nuclear waste products – dangerous for many thousands of years to come.
The waste from a molten salt reactor, says Irish, is much less potent, decaying to a safe state in about 300 years. __ Mississauga (John Spears)
A safer, more economical, scalable nuclear reactor is just what we need at this stage in the evolution of technology-dependent human societies. Nuclear technology provides heat and power on demand, unlike intermittent unreliable sources of energy such as wind and solar. And if the new nuclear reactor technologies work out, new nuclear will be at least as economical as natural gas — and far more economical than wind, solar, or old nuclear.
MSRs can be theoretically fueled with either uranium-based fuel or thorium-based fuel. Thorium has some advantages, but the uranium industry is much more mature, and at a more advanced stage of development. More efficient uranium reactors can power human societies for tens of thousands of years — and it is conceivable that thorium supplies could provide reliable power for a hundred thousand years or more.
The following images are from Next Big Future
Flibe Energy … championing the LFTR (liquid fluoride thorium reactor)
Beyond advanced nuclear fission reactors, we can look forward to fusion :: fision hybrid reactors, new fusion reactor designs, and more ways of tapping into the energies contained within the nuclear forces.
There are many crucial tests which humans will need to pass, before moving on to the next level. The mastery of nuclear forces in the creation of safe, peaceful, affordable, reliable, and abundant energy, is only one of those tests. Time to get serious about the future.
Peak Oil: Meet the heat that spells your doom! How high temperature nuclear reactors of the future will obliterate the very thought of peak oil.