If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Thorium THoughts

September 18, 2015 | A version of this story appeared in Volume 93, Issue 36

I was very pleased to see the article by Mitch Jacoby titled “Unleashing the Power of Thorium” (C&EN, July 6, page 44). The challenges of global warming are very real and will be difficult to deal with without a major contribution from a green nuclear power resource. Uranium-based systems have been shown to be difficult, expensive, and not very effective. A cleaner, safer, more effective, and less expensive alternative is much needed.

The last review of the thorium situation by C&EN was in 2009, in an article also by Mitch Jacoby (C&EN, Nov. 16, 2009, page 44). I am glad he is following the technology and its impact on global warming.

Carlyle Storm
Kingston, R.I.

The article on thorium failed to mention that the Alvin Weinberg group at Oak Ridge National Laboratory operated a liquid-fuel reactor for four years. Nor did it mention the 2010 American Scientist article by Robert Hargraves and Ralph Moir that made a compelling case for the use of thorium-232 in a liquid-fuel reactor (DOI: 10.1511/2010.85.304).

Currently all nuclear plants use uranium-235 as fuel. Nuclear-powered naval vessels use 235U of necessity. The question is why the Department of Energy will not permit an experimental liquid-fuel reactor powered by 232Th.

It is claimed that 1 lb of 232Th produces as much power as 300 lb of 235U or 3.5 million lb of coal, with far fewer environmental consequences. Thorium is more plentiful than uranium, and there is no danger of nuclear meltdown.

I am not a nuclear physicist but am interested in reducing the use of fossil fuels. Nuclear energy offers the most promising way of achieving this reduction, with 232Th being the most compelling option. I encourage C&EN’s readers to read everything they can on the use of 232Th as a replacement of 235U.

John H. Hash

I enjoyed reading the article about the renewed interest in thorium-based nuclear reactors and their associated history of neglect. Late in 1971, Houston Lighting & Power and Central Power & Light joined with San Antonio and Austin, Texas, to study the feasibility of nuclear power generation for their four jurisdictions. This ultimately led to the creation of what is now the South Texas Project Electric Generating Station near Bay City.

But what I recall vividly is a public hearing in the summer of 1973 (I believe), where I took a summer school chemistry class. At the hearing, Edward Teller (of H-bomb fame) was seen and heard by teleconference, long before Skype, advocating nuclear power (no surprise) but encouraging our utilities to use thorium as the basis for the reactions. Now it appears he was correct all along.

W. Patrick Cunningham
San Antonio

“Unleashing the Power of Thorium” brought to mind the summary I wrote of a symposium held at the urging of Edward Teller at Mitre Corp., in McLean, Va., on Oct. 25–27, 1979, on the topic “A Rationale for a Thorium-Cycle R&D Program.” Twenty nuclear-energy-minded experts attended, ranging from Teller (then at the Hoover Institution) to John F. O’Leary (former deputy secretary of energy), members of two national laboratories, industrial representatives, and foreign attendees from Canada, France, and Germany. The results fell on deaf ears.

I had been a group leader at Oak Ridge National Laboratory (ORNL) when it struggled to conduct the Homogeneous Reactor Test (HRT) using uranium (uranyl sulfate in heavy water) as the fuel with a thorium oxide blanket to be converted from 232Th into 233Th to protactinium-233 and on to fissionable 233U. The C&EN article calls the ORNL experiment “successful,” but the HRT itself failed in 1960 prior to testing with thorium, and the thorium research, both solid-fueled and molten-salt-fueled, was abandoned.

The new molten salt concept, particularly the “closed system,” looks to me to make it worth resurrecting the Thorium-Cycle R&D Program, updated of course from 35 years ago.

Richard S. Greeley
St. Davids, Pa.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.