Posted by Mark Halper

Chu Obama Charles Watkins Wiki

“Before I go Mr. President, let me tell you about these molten salt reactors.” That’s a completely made-up conversation. But outgoing U.S. Energy Secretary Steven Chu (l), this week did say that small modular reactors will be key to the country’s low carbon energy future. MSRs are one variety of them.

You might have missed the quiet announcement earlier this week: The U.S. Department of Energy has opened a second round in its $450 million program to fund small modular nuclear reactors, following its grant to Babcock & Wilcox late last year.

In a logical scenario, the next recipient would receive about $227 million, or roughly the same as what B&W is believed to have won.

“The Energy Department will solicit proposals for cost-shared small modular reactor projects that have the potential to be licensed by the Nuclear Regulatory Commission and achieve commercial operation around 2025,” DOE said in a press release.

Small modular reactors (SMRs) are much smaller than the gigawatt-plus size of new conventional designs. DOE said it is “seeking 300 megawatts or smaller.”

They auger lower costs because they can be manufactured in more of an assembly-line manner and transported complete to a site, and because they would allow utilities and other end users to add power in increments. They also lend themselves to installation in remote areas where they could provide a less expensive alternative to diesel generators.


Another advantage: they can potentially serve as sources of clean heat for industrial processes in factories and oil fields.

Outgoing Energy Secretary Steven Chu made it clear that they are an important part of a low carbon energy future.

“As President Obama said in the State of the Union, the Administration is committed to speeding the transition to more sustainable sources of energy,” Chu said in the release. “Innovative energy technologies, including small modular reactors, will help provide low-carbon energy to American homes and businesses, while giving our nation a key competitive edge in the global clean energy race.”

The DOE release also says that SMRs will offer “innovative and effective solutions for enhanced safety, operations and performance.”


With all that in mind, it seems to me that DOE should take a serious look at molten salt reactors (MSRs) and pebble bed reactors (PBRs), rather than only look at shrunken versions of conventional uranium fueled, water-cooled reactor, such as what B&W is building with its 180-megawatt mPower reactor (utility Tennessee Valley Authority plans to deploy two mPower units by 2021).

“Conventional” SMR companies like Nuscale Power, Gen4 Energy  and Westinghouse could well vie for the next round with small water-cooled reactors. But is this not also a funding opportunity for MSR companies like Huntsville, Ala.’s Flibe Energy and Cambridge, Mass.-based Transatomic Power?

Most MSR designs tick the “smaller” box, and would certainly qualify in the “enhanced safety, operations and performance” category. They are meltdown proof, operate at normal atmospheric pressure rather than at the high pressure of  many water-cooled designs, and they make more efficient use of fuel because they operate at higher temperatures. They also leave less waste, and in certain designs, can use nuclear wast as fuel. DOE’s 2025 target would be feasible.

Transatomic might be counted out if it sticks firmly to its intention to build a 500-megawatt reactor, which is above the 300 megawatt ceiling stated by DOE. But it seems that at their early stage of development, Transatomic could tinker with size.

Flibe fits right into the modular size, as it’s targeting between 10 and 50 megawatts, and up to 250 megawatts.


And don’t rule out a pebble bed option, either. Like MSRs, gas-cooled PBRs run at high temperatures. They fit well into small, modular form factors. A DOE-China collaboration ties the two ideas together, as it is looking into using molten salt coolants in solid fuel high temperature reactor (MSRs uses molten salts as part of their liquid fuel mix, as well as for the coolants that aborb the heat of a nuclear reaction and transfer it to a turbine).

In fact conventional giant Westinghouse is the commercial adviser to the DOE-China project, so it could have an interest in applying for funding for an alternative design, although it is almost certainly much further along with its small conventional reactor.

There is plenty of cross-pollinated interest among the various alternative parties that together could build a case for funding alternative nuclear. Westinghouse  – the commercial adviser to the U.S.-China molten salt coolant project – ran the Advanced Reactors track at last November’s American Nuclear Society’s annual winter conference (ANS) in San Diego, where the presentations included molten salts and high temperature reactors.

They also included talks by University of California Berkeley nuclear engineering head Per Peterson (he chaired the 5-day conference as well), who is known for his  interest in pebble bed reactors and in molten salt coolants. Peterson is also on the board of advisors at MSR company Flibe. In fact Peterson chaired the 5-day conference. Massachusetts Institute of Technology research scientist Charles Forsberg, a member of the DOE-China team, also presented in the alternative nuclear track.

Another MIT expert, Richard Lester, is a key adviser to MSR company Transatomic. Lester is the head of the department of nuclear science and engineering at MIT, where he is also the “Japan Steel Industry Professor” (I conjure up images of molten salt reactors supplying heat to steel mills when I see that).


And MIT, of course, is home to President Obama’s nominee for Chu’s replacement as Energy Secretary, the pro-nuclear physicist Ernest Moniz.

These individuals are not all united behind all the same causes and companies, but most of them share a big vested interest in alternative nuclear. It seems as though together, they could raise government interest – and backing – in the area.

Of course they’ll have to find funding elsewhere as well. I could imagine an oil company getting behind the development of a small MSR, for among other reasons, to use as a heat source. Or space agency NASA. The military might also want to invest – an MSR could help domestic bases disconnect from the creaky public grid, as Flibe president Kirk Sorensen has pointed out.

How about venture capital? Maybe. Flibe has added Bram Cohen to its board of advisers. Cohen is the founder of Internet company BitTorrent, where he has experience at raising $40 million in venture capital. Transatomic is getting ready to attempt a “Series A” round of venture financing.

Those possibilities could make a good mix. A DOE award should be a possibility. In the current round it might be a long shot. But so was the moon.

Photo from Charles Watkins, White House photographer, via Wikimeda


  1. onyerlefty says:

    Both Former Secretary Chu and Secretary Moniz seem to have a bias against MSRs because of the corrosion issue, even though Oak Ridge documents from the 1970s suggest the problem was largely solved. Chu:
    “One significant drawback of the MSR technology is the corrosive effect of the molten salts on the structural materials used in the reactor vessel and heat exchangers; this issue results in the need to develop advanced corrosion-resistant structural materials and enhanced reactor coolant chemistry control systems. In addition, operational practices would have to address the fact that the liquid salts solidify between temperatures of 300 C to 500 C, thereby requiring the use of special heating systems when the reactor is not operating.”
    Even though U-233 would never leave the reactor vessel, Chu expresses concerns about proliferation:
    “From a non-proliferation standpoint, thorium-fueled reactors present a unique set of challenges because they convert thorium-232 into uranium-233 which is nearly as efficient as plutonium-239 as a weapons material.”
    Moniz hasn’t mentioned MSRs publicly since his nomination, but in MIT’s “The Future of the Nuclear Fuel Cycle” (2009), of which Moniz was co-chair, only advanced LWRs are recommended for development in coming years. The study claims 50-100 years are required for fuel cycle transitions (how would JFK respond, were he told a Moon program would require a similar period of development?).

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