Dr. Frank Shu: An Astrophysicist Offers An Outsider’s View on the Future of Energy

Dr. Frank Shu is beaming. “That’s it!” he smiles broadly, extending a hand to a colleague. The excitement is palatable in the sweat-soaked tropical heat of the Taiwanese afternoon. Applause breaks out among the students and professors in the large shed behind the sciences building at National Tsing Hua University. Success arrives in the form of a metal basket filled to the brim with blackened wood chips. And it’s arrived with little time to spare.

“All right!” Dr. Shu adds above the rising chatter of local and Chinese film crews on-hand to witness the momentous occasion. “To the airport!”

Shu, 71, has spent decades researching the great questions of the universe. In the early 60s, the Chinese-born American professor launched a long and distinguished career in the sciences developing a theory about the spiral arms of galaxies as an undergrad at MIT. By the end of the decade, Dr. Shu graduated from Harvard with a PhD in astronomy.

Over the years, he’s served on the faculty of UC Berkley and UC San Diego. In 2002, Dr. Shu was appointed the president of National Tsing Hua in Hsinchu City, Taiwan, shortly after the passing of his father, Dr. Shu Shien-Siu — a celebrated academic in his own right, who founded the Department of Mathematics at Tsing Hua and served as the school president in the 1970s.

In the intervening years, the pioneering work of Dr. Shu Junior earned him a wall full of accolades, including, most recently, the prestigious 2009 Shaw Prize for “Outstanding Contributions in Theoretical Astronomy” — recognition of a life dedicated to answering some of the greatest scientific questions of our time.

Career Change

Slowing down was never an option. Well into his 60s, the celebrated astrophysicist planted the seeds for a seemingly abrupt career shift. “I’ve always been concerned about climate change,” Dr. Shu explains. “But it was only five or so years ago that I realized that the problem that I thought would long be solved wasn’t being solved. And there were many, many conflicting ideas as to where the solution lay.”

He rates the issue as, quite possibly, the most pressing long-term concern facing society. “I think that if it progresses to the worst scenario projected, that it can disrupt civilization,” Dr. Shu, the seemingly near-permanent smile leaving his face. “It will become so disruptive of all of our social and national interests that civilization could dissolve into chaos.” In the 2000s, Dr. Shu published a paper examining the issue from, as he put it, the perspective of an astrophysicist — an attempt to offer the point of view of an outsider looking in.

“I think an astrophysicist views the Earth as one of many [planetary] systems, so we look at the Earth as a whole, and we’re able to assess the various contributions to energy potential, from fossil fuels to nuclear energy to sunlight to wind in a unified way,” Dr. Shu explains. “That’s what my energy article was about, [assessing the] potential. And once you put it in an astronomical perspective, you realize all of these energy sources come from astronomy. I hope we’re able to put that in an astronomical way.”

But for the professor whose esteemed career was founded, in part, on the development of scientific theory, publishing a paper wasn’t going far enough to address such an urgent issue. “I discovered in writing that article, I felt a sense of guilt that here was this very important problem and it wasn’t enough for me to give advice,” says Shu. “I thought I had to contribute to finding rational and reasonable solutions.”

Making Biochar

The reward for his work thus far appears to be little more than a metal basked full of charcoal. But his team’s brief celebratory break from work is understandable. The sooty burnt wood represents a hope for the future. After years of work, the team has produced a carbon neutral — or even carbon negative substance from a bucket of unwanted biomass — biochar.

“This is an invasive species that’s common to much of Southeast Asia,” Dr. Shu explains dipping his hand into what looks like a bucket of wood chips. “It came from Mexico originally. It’s called leucaena, and it’s considered an invasive bush. It’s very hard to make furniture out of the stuff. Nobody wants it. The farmers consider it a nuisance, but we can use it as a starting point for fuel.”

The industrial equipment that occupies the majority of the shed generates enough heat to melt salt into a molten form. Applied to the biomass — the aforementioned invasive bush — in the absence of oxygen, Dr. Shu and his team have created manmade charcoal in ten minutes flat. The energy source can be used as a carbon-negative alternative to environmentally destructive and finite fossil fuels. Buried under a lawn, the biochar’s benefits are even more pronounced. “An even better use for this is to put it into the ground, so it’s actually carbon negative,” says Dr. Shu. “It sequesters the carbon that would have gone back into the air if you had let that biomass rot.”

A Nuclear Future

National Taiwan University in nearby Taipei houses an even more ambitious piece of Dr. Shu’s energy puzzle, a two-foot tall graphite reactor module. It sits on a work bench, at the moment serving more as a symbol of untapped potential of the scientist’s true passion: nuclear energy. Utilized alongside the molten salt reactor currently generating biochar 40 minutes away, Dr. Shu believes he has a solution that can address much of the concern surrounding nuclear energy by removing meltdown fears from the equation.

“There’s not a meltdown [possibility] because the salt is already molten. In some sense, you’ve planned for the meltdown,” says Dr. Shu. “You’re operating under meltdown conditions The thing you’re actually afraid of is freezeups, where the salt drops below its melting point. Once it gets out of the reactor, it starts to cool, because there’s no more heat from the nuclear energy, so it starts to cool down and freeze. So, we’ve designed the rest of the plant in such a way that it will freeze in 10 seconds. So, before it can get out of this room, it’s on the floor. It’s frozen. So that means it’s immobilized, just the opposite of what you’re afraid of in regular nuclear reactors, where you’ve designed something to be solid, and now it’s gone beyond your design and become liquid. That can flow.”

Removing the need for constant cooling also means that plants utilizing Dr. Shu’s methods don’t need to be situated near large bodies of water and therefore are easier to situate in more sparsely populated areas.

For Dr. Shu, still further hope lies in thorium, an abundant element unintentionally stockpiled in countries like the US and China as a biproduct of mining. The professor explains, “It’s been known since the beginning of the nuclear age that there are two kinds of material that can become fissionable, if you add a neutron to them. When you add a neutron to thorium, it becomes a lighter version of uranium, which is fissionable. It is four times as abundant as the most abundant form of uranium.”

The other major benefit of thorium is the fact that — unlike conventional nuclear reactors — it generates no weaponizable waste in the process of generating energy. “It’s also much cleaner [than uranium],” he says. “Very little plutonium results from this kind of reactor. It keeps circulating until it’s gone. This kind of reactor will never produce weapons-grade plutonium.”

And while Dr. Shu and his team have plenty of work ahead of them when it comes to convincing the powers that be and the public at large that nuclear is a largely safe and clean method for generating energy, the scientist has no doubt of its potential power.

“There are two kinds of nuclear energy,” Dr. Shu explains with a smile. “One of them comes from fusion, which is how stars make energy, when you combine light elements and make heavy elements. The other comes from fission, which is the way we use nuclear energy today. You take heavier elements and you break them apart, releasing energy. Both of those are astronomical. Fusion relies on events that took place in the big bang. Fission relies on supernovas, the process that makes neutron stars. Every astrophysicist knows those are the two most powerful events in the universe, so they’re hard to beat.”

Related Videos: 




  • Reply November 14, 2014

    Oliver Tickell

    It’s true that thorium reactors produce no weaponisable plutonium. But they do produce weaponisable uranium – the isotope 233U. It’s also true that they do not produce as many long-lived trans-uranics, but there are still plenty of highly radiotoxic fission products, as well as the very powerful gamma emitter 232U. The thorium-uranium cycle is preferable to the uranium-plutonium cycle, but not all that much better. There are also huge engineering challenges to be overcome – even just finding materials capable of surviving the intense neutron bombardment. In the end all nuclear power will be defeated by renewables, which have none of these problems and – especially solar PV – are getting cheapr every week.

    • Reply November 19, 2014

      mark caldo

      Nobody included the world’s experts have yet made a viable U233 weapon. Why bother – much easier to use uranium.

      All the world’s nuke waste now fitting on a football field, would fit in ateam locker room after powering all the world’s energy needs for a thousand years burned up in an MSR. Compared to the tens of cu miles of deadly toxic forever end of life solar panels now heading to landfills to leach in water supplies worldwide, it seems almost benign.

      There are no engineering challenges related to molten salt reactors.

      I’d recommend Olly begin his learning process here with “terrestrial-energy-molten-salt-reactor-designed-commercial-success”

      Keep in mind that over 7 million folks worldwide die annually from fossil air pollution, a problem France nearly eliminated decades ago in 10 years with a almost trivial effort, building nuke power at half the cost of fossil fuels.

  • Reply December 18, 2014

    Raw Science

    Oliver Tickwell and Mark Caldo: Dr. Shu’s response to your comments is below.

    “Oliver Tickwell and Mark Caldo make valid points. However, power reactors of any kind are unsuitable of making nuclear weapons for a very fundamental reason. They produce a flood of neutrons that quickly produce contaminating isotopes – Pu-240 in the case of Pu-239 bombs or U-232 in the case of U-233 bombs – that render such efforts ineffectual. To produce nuclear bombs, there are only two proven paths: enrich natural uranium so that U-235 is more than 90% of the total uranium or special nuclear reactors that release neutrons so slowly that it is possible to remove Pu-239 from the reactor before it absorbs another neutron and becomes Pu-240. Neither path is available to power reactors. Linking nuclear power to nuclear weapons is a false association.

    Comparing electricity from non-dispatchable solar PV to electricity from dispatchable nuclear power plants is an also unproductive activity. They both have positive roles to play in de-carbonizing the primary energy supply chain. But solar PV is not cheap if one considers actual energy generated (nameplate power multiplied by the effective time that one gets to use that nameplate power over the course of a year) because the effective time is typically only 20% the number of hours in a year. At high latitudes like Germany, the capacity (or load) factor is only about 10%; while it is more than 90% for nuclear power plants in France where Germany imports much of its clean electricity when the Sun isn’t shining or the wind isn’t blowing. While it is true that solar panel prices have plummeted over the last decade, total costs per kWh have leveled off in recent years because the costs of installation and maintenance do not decrease with time. Nevertheless, the threats of looming climate change are so fearsome that it would be foolhardy to eliminate any effective weapon we have to combat it.

    It is misleading to claim that molten salt reactors do not have their technological challenges. Intense bombardment by fast neutrons does make metal brittle on time scales of 2 years or less (which explains why metal-alloy fuel rods in conventional light water reactors need to be replaced typically every 18 months); and they will also cause dimensional changes in nuclear-grade graphite on time scales as short as 4 years, unless one uses enough graphite to moderate most of the fission neutrons to slow speeds. There is also the matter of decay heat, which is not solved merely by having freeze plugs and dump tanks. Freeze plugs take too long to respond to emergency conditions. To deal with the decay heat problem in dump tanks in a completely safe way, one either has to build only very small reactors (to decrease the ratio of the volume where the decay heat is generated to the surface area where the decay heat can be carried away by passive systems), or one must possess the capability of on-line cleaning of fission products from the fuel salt. The latter capability is also crucial to breeding Th-232 into U-233, so well-designed thorium breeder molten-salt reactors can automatically be walk-away safe, whereas other designs cannot automatically make this claim unless they are built at very small sizes.

    Finally, the store of used fuel from light-water reactors is the only plausible nuclear material abundant enough in the world to start up the desired fleet of thorium molten-salt breeder-reactors. We should not wantonly burn up this resource for temporary use if we want sustainable nuclear power that can supply most of the primary energy needs of the 21st century and beyond.”

  • Reply January 9, 2015

    Keri Kukral

    For those following this story, there is an interesting discussion on a related video on our YouTube channel: https://www.youtube.com/watch?v=woNU2Vgl7j0

  • Reply January 21, 2016


    There is technology out there that has better efficiency than steam engine: http://www.bloomenergy.com/

Leave a Reply Click here to cancel reply.

Leave a Reply to Anonymous Cancel reply