By Zeeshan Hasan.
First published in Dhaka Tribune on 16 November 2021 at https://www.dhakatribune.com/opinion/op-ed/2021/11/16/op-ed-stop-global-warming-with-molten-salt-reactors
Decades of UN climate negotiations have yielded few results; our use of fossil fuels is still increasing, producing carbon dioxide emissions which are heating up our planet to dangerous levels. And yet, things didn’t have to be this way. Decades ago, visionary nuclear scientists like Dr. Alvin Weinberg, author of “The First Nuclear Era” (published 1994), proposed that fossil fuels could be eliminated and global warming solved by widespread adoption of nuclear power. Dr. Weinberg was formerly head of the Oak Ridge National Laboratory, one of the primary sites of nuclear reactor research in the USA, and co-inventor of the “light water reactor” design which has become the mainstay of nuclear power all over the world. However, he also foresaw that the risk of serious nuclear accidents which could occur at light water reactors (such as Chernobyl and Fukushima) would turn the public against nuclear power, and limit its promise of supplying fossil-fuel free energy to the world. Thus he designed a safer nuclear reactor called the Molten Salt Reactor, which still promises to be a safer and virtually limitless source of zero-carbon power. The climate crisis and the urgency of replacing fossil fuels makes this a critical discovery which everyone should know about.
Dr. Weinberg first points out that his design of the light water reactor (also called the pressurised water reactor) was adopted not due to either safety or economy; but simply because Admiral Hyman Rickover of the US Navy, found it most appropriate for the Nautilus nuclear submarine program.
“The coolant for the nuclear submarine reactor had yet to be determined. Rickover himself seemed to favour high-temperature sodium… I naturally called to their attention the ideas we had developed on the use of pressurised water. For a submarine reactor, pressurised water had two main advantages; first, a reactor based on it would be small enough to fit comfortably in a submarine… second, water, unlike sodium, was something the Navy ought to know about… Thus was born the pressurised water reactor… not because it was cheap or inherently safer than other reactors, but rather because it was compact and simple and lent itself to naval propulsion. But once pressurised water was developed by the Navy, this system achieved dominance.” (page 59)
However, the pressurised water reactor was not the only alternative for nuclear power. Dr. Weinberg also also developed the Molten Salt Reactor, which was designed to be inherently safe as it could not overheat and experience “meltdown”. This was recognised as a risk for pressurised water reactors if their nuclear control rod systems were defective (as at Chernobyl) or if their water-based pumping and cooling systems were stopped (as at Fukushima). The Molten Salt Reactor was successfully tested over 3 years at Oak Ridge:
“The molten-salt reactor began operation early in 1966 and achieved its maximum power… in March of that year. It continued to operate remarkably smoothly, though with interruptions for maintenance, until December 1969, when its operation was terminated so that funds could be diverted to the development of more advanced molten-salt systems. We were delighted with the MSRE (molten-salt reactor experiment)” (page 126)
Unfortunately, the Molten Salt Reactor was too late to influence commercial reactor design, which had already established an unstoppable momentum around the light water reactor:
“By 1953, the main line of reactor development in the United States was pretty well established; it was the light water reactor (LWR)… the LWR… had one overwhelming advantage; it had already proven itself as a reliable power plant in the Nautilus” (page 133)
The selection of the light water reactor by the commercial nuclear industry left it open to the possibility of catastrophic failures, against which the first generation designs of light water reactor did not have adequate safety measures.
“Even before Three Mile Island… I tried to convince the nuclear industry people that drastic action was needed if nuclear was to survive… on the basis of Norman Rasmussen’s estimates of the likelihood of a reactor accident, a reactor meltdown was all but certain within a few decades... the reactor would be destroyed, and this would bankrupt the utility that owned and operated the reactor, as well as greatly compromising the future of nuclear energy.” (pages 227-8)
Dr. Weinberg’s repeated warnings regarding the possibility of nuclear accidents in light water reactors cost him dearly; ultimately he was fired from his job as director of Oak Ridge National Laboratories. Unfortunately, Weinberg’s worst fears came true when the Chernobyl disaster occurred:
“Then came Chernobyl in April 1986. The nuclear enterprise throughout the world had to face the real possibility that the first nuclear era would be aborted.” (page 232)
Weinberg passed away in 2006, but his prediction of nuclear disaster in light water reactors was further reinforced after the 2011 Fukushima accident, which effectively ended public support of nuclear power in most Western countries. Weinberg’s prediction of the demise of the light water reactor industry led him to call this initial phase of nuclear power “the first nuclear era” (hence the title of his book). He foresaw the safer Molten Salt Reactor design taking over the nuclear industry afterwards:
“I visualised a second nuclear era based on an inherently safe reactor… Once the public realised that a meltproof reactor had been developed, its objections to nuclear energy would disappear. ” (page 231)
Unfortunately, Dr. Weinberg never lived to see his dream of the Molten Salt Reactor commercialised, largely due to the protests against nuclear power by anti-nuclear environmentalists who favoured solar and wind over nuclear energy. This was a tragic development, as nuclear has long been the only zero-carbon large scale source of continuous energy capable of replacing fossil fuels and stopping global warming.
“Carbon dioxide poses a dilemma for the radical environmentalist. Since nuclear reactors emit almost no carbon dioxide, how can one be against nuclear energy if one is concerned about carbon dioxide?… To my dismay… this is exactly the position of some of the environmentalists. Their argument is that extreme conservation, and a shift to renewables – that is, solar energy – is the only environmentally correct approach to reducing carbon dioxide. When I point out to them that conservation may be feasible in industrialized countries, but that it is hardly a choice for India and China, they seem to ignore the point.” (page 237)
Fortunately, a number of companies and government agencies around the world have taken up Weinberg’s Molten Salt Reactor design and are currently trying to commercialize it. The first proof-of-concept Molten Salt Reactor is about to be completed in Wuwei, China. Hopefully, within a few years, Weinberg’s dream of a second nuclear era powered by inherently safe Molten Salt Reactors will become a reality. One hopes that this will be in time to save the world from climate castastrophe.
