Molten-salt reactors & the thorium/LFTR concept

Bob Hargraves, the author of Thorium: Energy Cheaper than Coal, recently traveled to Shanghai to present a 30 minute talk summarizing the main points of discussion that he covered in his book. The occasion of the trip was Thorium Energy Conference 2012. Bob is a professor with a good facility for numbers and a talent…

Bob Hargraves, the author of Thorium: Energy Cheaper than Coal, recently traveled to Shanghai to present a 30 minute talk summarizing the main points of discussion that he covered in his book. The occasion of the trip was Thorium Energy Conference 2012.

Bob is a professor with a good facility for numbers and a talent for clear explanations. He provides reasonably accurate figures for most types of energy production systems available today using credible sources and showing his math. As he demonstrates, there is little hope of driving down the total cost of producing energy from unreliable, weather dependent sources because the capital investment in those sources will often be idle and not producing any revenue. That characteristic makes the revenue requirement for capital cost recovery impossibly uncompetitive.

He persuasively demonstrates that well-designed and built nuclear plants whose operators successfully achieve capacity factors in the range of 85-90% are already cost competitive with coal. He also shows how nuclear plant designers can apply well understood techniques to achieve even better economic performance.

There are a few areas where Bob and I part ways. My major beef with his analysis is his acceptance of old cost estimates for vaguely defined thorium power plants and his method of adjusting those already unreliable cost estimates by applying a standard inflation adjustment factor. As Bob acknowledges later in his talk, there really is no basis for estimating the initial cost of any power plant until there is a pretty solid design concept that is not going to change. Without a design, any cost estimate has about the same chance of hitting a target as a dart from a blindfolded thrower who has been spun around a few times before letting loose.

Bob also fails to apply his well explained learning curve logic to other forms of nuclear power. There is nothing that stops them from going smaller and adopting series production techniques. There is also no evidence that conventional nuclear plant builders have used up the potential gains from that technique already. Hargraves and I agree that the best way to reduce the cost of building nuclear power plants is to apply the same series production techniques and the same kind of factory-based quality control systems that enable economical commercial aircraft or large commercial ship production.

During the Q&A session after Bob’s talk, one of the conference attendees, Baroness Byrony Worthington, raised a question that I have often faced when discussing future energy systems. She seemed almost offended that Bob had revealed the true cost of weather dependent unreliables (aka renewables). She told Bob that he should be seeking a big tent with room for all “low-carbon” energy systems in the battle against coal.

There was a time when I had essentially the same belief and enthusiasm for alternative energy systems. I used to think about effective ways to use the fallen logs I saw as I drove through forested land and about building solar collectors. Even during that stage in my energy thinking, I had already spent a lot of time as a competitive sailor, so I was pretty skeptical about the prospects for commercially using wind energy. I’d experienced too many becalmed days on the ocean and missed too many days of racing due to lack of wind to be very excited about wind as being anything but a challenging source of hobby power.

The thing that opened my eyes to the limitations of biomass, solar, ocean thermal, and wave energy was taking a series of 400 level alternative energy engineering classes taught by Chih Wu, one of the men who wrote the book about Ocean Thermal Energy Conversion (OTEC). Chih (who told his colleagues to call him Bob) was a well-respected professor of mechanical engineering at the US Naval Academy, which is where I landed after my engineer officer tour on USS Von Steuben.

As a member of the Naval Academy staff, I could audit courses for free; it was an employment benefit that few of my colleagues used. I However, I was motivated because I wanted to bulk up my engineering knowledge level: even though I had completed a successful assignment as an engineer officer, I recognized that my English undergraduate degree would be inadequate if I wanted to pursue a technical career outside of the Navy.

After three semesters of pretty intensive study, I had convinced myself that there was no way that unreliable systems with capacity factors in the 18-40% could ever be made economical. The project assignment that I remember most clearly designing a solar heater for a swimming pool located on the coast of California. Even if I used very optimistic numbers for the solar energy input, the collectors still required a surface area that was larger than the pool. The pool also had to be covered for about 15 hours per day to prevent evaporative losses from cooling it below a moderately comfortable temperature of 72 degrees.

Bob and I often conversed about his choice to become a renewable energy expert. It took some time, but he finally admitted to me that he would have preferred to pursue his initial interest in nuclear energy. Unfortunately, the money for research projects in that field had virtually disappeared by 1972. Even though Bob taught at the Naval Academy, a place where research success is less important than teaching performance, he wanted to pursue interesting intellectual projects, obtain grants that would support student research and find ways to fund experimental construction efforts.

My motivation for learning more about energy options was to provide energy that is cleaner, cheaper, and more reliable than coal. That energy is also cheaper and more reliable than any form of energy that depends on the vagaries of the weather. I recognize that there is no hope for a big tent because successful pursuit of my goal will drastically reduce the market opportunities for all other forms of energy production.

The people who stand to lose market share will never like the effect of enabling nuclear energy to succeed, so they are unlikely to invite nuclear energy into their tent unless their intention is to sabotage its prospects for success. People who talk or write about energy might see logic in trying to bring all supporters of low carbon energy together, but people who want to sell systems will have a different point of view.

The most likely allies in the battle to make nuclear energy cheaper are energy consumers; they are motivated to ensure that their sources are the cleanest and cheapest available. Since nuclear energy is unlikely to ever power personal transportation or aviation, there is also a coalition possibility with coal, as unlikely as that might sound at first.

Cheap nuclear energy could be used to upgrade coal into a clean hydrocarbon fuel that could compete directly against oil in the liquid fuel market. Burned directly, coal sells for about $1.50 – $3.00 per million BTU. Crude oil, on the other hand, commands a market price of about $16.00 – $24.00 per million BTU in the recent world price range of $90.00 to $135.00 per barrel.

If nuclear energy can be used to economically convert coal to a liquid hydrocarbon that could be piped to market, it would open a large range of new opportunities for coal miners and coal mine owners. Since the US has large domestic coal resources and since I like union laborers, I think that is a match worth pursuing.

The key enabler of a vision of a cleaner, more abundant, less costly energy system is infusing nuclear technologists with a cost conscious culture that is as much a part of their decision process as their already important safety culture. That cost conscious culture must be well understood to discourage cheap, short-term thinking. It requires a full system view that recognizes the enormous cost that would be incurred from early failures due to using inadequate materials. It must also recognize the hazard and potential cost of taking short cuts that eliminate necessary steps or useful second checks. Experienced operators can help designers understand the value of simple, well-constructed equipment that lasts and lasts.

However, the industry has some work to do to eliminate the “cost is no object” mentality that pervades the industry. We have to stop allowing people to cloak their cost-increasing demand for zero defects or perfection in low priority activities as motivated by a “safety