Energy From Thorium Discussion Forum

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PostPosted: Jun 12, 2013 5:01 pm 
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Kirk has provided a great historical account (in 20 chapters) of the development of the nuclear reactor, from the initial discovery of thorium and radioactivity to the Manhattan Project and more. I highly recommend this entire piece for your consideration. It will give you a real feel for the way our historical thread has evolved and the considerably talented people who made it happen. Plus, it is fun to read of details you may not know.

See: http://flibe-energy.com/?p=637


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PostPosted: Aug 14, 2013 10:57 pm 
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My thesis:

Thorium Research in the Manhattan Project Era

is at a stage of completion where I invite comments and suggestions. The abstract reads:

Quote:
Research on thorium as an energy source began in 1940 under the direction of Glenn Seaborg at the University of California in Berkeley. Following the discovery of plutonium-239 and its fissile qualities, similar experiments demonstrated that uranium-233 bred from thorium was also fissile. Seaborg viewed uranium-233 as a potential backup to plutonium-239, whose production was one of the Manhattan Project's primary efforts. Unlike plutonium, the chemistry of uranium was well understood, which added to the appeal of U-233. But plutonium-239 had the potential to be produced from natural (unenriched) uranium in a chain-reacting pile, while U-233 could not be produced in this manner from natural thorium (which lacked fissile isotopes). Not until the X-10 graphite reactor was constructed at Oak Ridge in 1943 was sufficient U-233 created to conclusively assess its nuclear properties, which were found to be superior to Pu-239 in a thermal-spectrum reactor. Early production of plutonium at X-10 showed significant contamination by Pu-240, which made plutonium unsuitable for simple "gun-type" nuclear weapons. Researchers in the "Metallurgical Laboratory" at the University of Chicago, which included Seaborg's chemistry group, suggested that the plutonium produced be used as a fuel in a special reactor to convert thorium to uranium-233 for weapons. This effort encountered many severe difficulties in fuel fabrication and dissolution. Seaborg also recognized the severe issue that uranium-232 contamination would play in any effort to use uranium-233 for weapons. Through tremendous effort, weapons designers at Los Alamos were able to design workable weapons using the implosion principle, which accommodated for the impure plutonium produced. Interest in U-233 for weapons effectively disappeared by 1945, but the Metallurgical Laboratory continued to investigate the potential of a thorium-U233 "breeder" reactor, based on a homogeneous mixture of uranium salts in heavy water. This effort also came to an end in early 1945. With the use of nuclear weapons on Japan in August 1945 and the end of World War II, many questions were asked about how nuclear reactors, nuclear power, and nuclear weapons would develop. Interest in the liquid-sodium-metal-cooled, fast-breeder reactor came to dominate, since it promised to increase the supply of rare fissile material rather than reduce it. Research on thorium and homogeneous reactors faded, but their involvement in early research led to later interest by Eugene Wigner, Glenn Seaborg, and Alvin Weinberg. The United States was fully focused on growing its nuclear weapons stockpile, and the success of the implosion weapon using plutonium, coupled with its natural advantage in production from unenriched uranium, led to limited interest in thorium as the Manhattan Project ended and the Atomic Energy Commission began in early 1947.


Its focus is the research that was done on thorium for nuclear applications from the discovery of uranium-233 up until the end of the Manhattan Project on December 31, 1946.


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PostPosted: Aug 15, 2013 9:19 pm 
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I liked it very much. I liked the pictures it made it seem more real to me.

I obviously didn't read too much, but I did read the preface on how thorium energy was abandoned because it reduced the rare fissiles instead of the uranium that produced the rare fissiles.

It looks very good, I will try to read all of it. The history of uranium vs thorium for energy is something that should never be forgotten.


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PostPosted: Aug 17, 2013 3:46 am 
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I assume that U-234 has less damaging properties for bomb use than Pu-240 does?
Otherwise you wouldn't gain anything by using the plutonium to make uranium in a reactor.


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PostPosted: Aug 17, 2013 7:35 am 
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The problem with 240Pu is that it ejects a neutron too often that prematurely sets off the explosion. This is due to its spontaneous fission rate. The half life for 240Pu is 6569 years with a 5e-8 probability that there was a spontaneous fission rather than decay. The similar numbers for 234U are 246,000 years and 1.6e-11. So the SF rate for 234U is 117,000 times less than 240Pu.


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PostPosted: Aug 17, 2013 2:47 pm 
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Great work Kirk, looking forward reading more of your thesis.


From Lars above

Quote:
The problem with 240Pu is that it ejects a neutron too often that prematurely sets off the explosion. This is due to its spontaneous fission rate. The half life for 240Pu is 6569 years with a 5e-8 probability that there was a spontaneous fission rather than decay. The similar numbers for 234U are 246,000 years and 1.6e-11. So the SF rate for 234U is 117,000 times less than 240Pu.


Kirk's thesis brings up the surprising issue that Seaborg was quite worried about spontaneous fission in U232 during the Manhattan Project (in looking at U233 for weapons). I guess maybe since they could quickly find the short half live of U232 but not so easily find out the chance of this decay being fission? You'd think once they made some U233 they'd just be able to measure the neutron generation rates even back in the 1940s? Strange...

It is still very hard to dig up U232 spontaneous fission rates as everyone seems to ignore it. Finally found it quoted in Bruce Hoglund's paper from many years back where he quotes from a 1971 source (table 5). U232 is indeed the highest spontaneous rate of the U isotopes but still no where near those of Pu isotopes (about 600 times lower than Pu240 and of course U232 is never more than a tiny fraction of produced U233).

http://home.earthlink.net/~bhoglund/multiMissionMSR.html

David LeBlanc


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PostPosted: Jan 28, 2014 1:41 pm 
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My thesis was successfully defended yesterday at the University of Tennessee. I have been invited to give a colloquium on the topic in the near future.


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PostPosted: Feb 08, 2014 5:55 am 
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Kirk Sorensen wrote:
My thesis was successfully defended yesterday at the University of Tennessee. I have been invited to give a colloquium on the topic in the near future.


I read everything you wrote. Was very helpful to understand how Thorium played in the early nuclear days.
Something equivalent on the 50s and 60s (before the Oak Ridge MSR experiment) would be very interesting as well.

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PostPosted: Feb 08, 2014 10:34 am 
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Here's a bit of trivia that sheds light on the culture at Oak Ridge during the war. The acclaimed science fiction writer Theodore Sturgeon wrote this in an introduction in his 1979 collection The Stars are the Styx:
Quote:
A great many scientists and technologists are involved in science fiction. During the Big War, the largest block of subscriptions to Astounding Science Fiction was in Oak Ridge, Tennessee, and the next largest in Hanford, Washington -- facts, John Campbell told me, that the German military intelligence never discovered or noticed.
John Campbell was the editor of Astounding, the nation's leading science fiction publication at the time, from 1937 onward. He had an undergraduate degree in physics and took the magazine in a more scientifically rigorous direction. He introduced such writers as A.E. van Vogt, Isaac Asimov, Theodore Sturgeon, and Robert Heinlein. The "Golden Age" of science fiction is associated with Campbell's influence before and during the war.

Science fiction writers during the war were deeply concerned with atomic power, largely due to Campbell's editorial guidance. Here is an edited paragraph from the Encyclopedia of Science Fiction that explains the type of stories and editorials that Oak Ridge researchers were reading.
Quote:
Nevertheless, atomic power would have been simply one more idea in the extravagant vocabulary of pulp-magazine sf had it not been for Campbell. Campbell's first published story featured the release of energy by the destruction of matter; and one of his earliest stories was "Atomic Power." He took a serious interest in progress in this area of science and popularized such research for the readers of Astounding. He discussed contemporary developments in his editorials, and actively encouraged his writers to consider the possibilities seriously. He made the scientific issues so familiar that even a routine space opera in 1941 could hinge its plot on the esoteric problem of isotope separation. Other story plots included:

- the psychological stress involved in working with a nuclear-power plant and its potential hazards
- radioactive dust as a weapon of war, and the difficulties of exercising control over such use
- an accident in a nuclear-power station which threatens to become a major disaster
- and of course, the atomic bomb


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PostPosted: Feb 08, 2014 1:33 pm 
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Really enjoyed this post.
Thanks


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PostPosted: Aug 08, 2014 12:24 pm 
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My thesis now available through the University of Tennessee:

Thorium Research in the Manhattan Project Era


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PostPosted: Aug 10, 2014 5:59 pm 
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Good Luck Doc!


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PostPosted: Sep 01, 2014 12:20 pm 
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Kirk Sorensen wrote:
My thesis now available through the University of Tennessee:

Thorium Research in the Manhattan Project Era

MS or PhD?

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PostPosted: Sep 01, 2014 3:58 pm 
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KitemanSA wrote:
Kirk Sorensen wrote:
My thesis now available through the University of Tennessee:

Thorium Research in the Manhattan Project Era

MS or PhD?

I believe Kirk already has a MS in aerospace engineering.
"He is also a PhD student in nuclear engineering at the University of Tennessee in Knoxville under Dr. Laurence Miller"
from:
https://www.youtube.com/watch?v=rv-mFSoZOkE
Dr. Sorensen's Google Tech Talk.

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PostPosted: Sep 01, 2014 6:22 pm 
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MS in aerospace engineering, Georgia Tech, 1999
MS in nuclear engineering, University of Tennessee, 2014

no longer working towards a PhD, had to give up that dream when I started a nuclear company.


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