Sam Cohen is best known as the inventor of the neutron bomb an accomplishment that has brought him the admiration of many Americans and the enmity of a few. He is also known for his advo cacy of a libertarian foreign policy. The interventionist games Ameri can politicians like to play with the affairs of other countries are often fundamentally wrong. Sam Cohen points out that, with the great ad vances in mass destruction technology, foreign intervention has also become very dangerous. Today's unfortunate victim of American'peace keeping' may be tomorrow's terrorist, and he may be equipped with very dangerous technology. Recently Sam Cohen sent me a brief account of a new sort of nuclear power plant that he thinks is now possible. You may wish to compare this idea with the new nuclear power idea described by Ed-ward Teller in the October
"In the nuclear explosives area, programs had been established in the 1950s in the US and USSR aimed toward developing 'pure-fusion' devices that unlike other devices used no fissile materials (uranium-235 and plutonium). Instead, they banked on being able to ignite very small amounts of heavy hydrogen, deuterium and tritium (which must be produced in nuclear reactors through the absorption of neutrons in lithium). Such explosives held the potential for being extremely cheap, the tritium cost being orders of magnitude less than the plutonium (also produced by neutron absorption in reactors) used in a fission weapon. In addition, such explosives, known as 'clean' devices, would release levels of radioactivity essentially insignificant compared with that from fission explosives.
"By the time the NPT was consummated, the U.S. pure-fusion program had been unsuccessful and expectations were it would remain so, which has been the case so far. (That is, at least in the U.S.; on the Russian side they stopped reporting more than 30 years ago, and we simply don't know what they have accomplished.) "As a consequence, the monitoring constraints contained in the NPT concerned only fissionable materials. No mention was made of tritium and insofar as using it in peaceful explosives, in no way was this forbidden. In fact, such application was considered an 'inalienable right.' "During the 1960s and 1970s, the U.S. maintained a peaceful explosives program, entitled
PLOWSHARE. One particular effort, Project Pacer, explored by the Los Alamos laboratory, envisaged the underground bursts, several times a day, of explosive devices having a yield of about 20 kilotons, where a relatively small fraction of the yield came from a fission trigger which ignited thermonuclear fuel which in turn very substantially reduced the overall radioactive contamination problem. Such devices would be burst in large steam-filled underground chambers. The superheated steam would then be piped to the surface and used to generate electricity in a conventional manner. Preliminary calculations indicated this approach held considerable economic potential. However, so great was the political resistance to bursts of such large yield and the accompanying production of such huge amounts of long-lived radioactivity that the project came to an inglorious ending."As for the pure-fusion devices the US and USSR had explored, yields on the order of 10 tons (0.0l KT) were of interest; namely, thousands-fold less than the Los Alamos scheme. Aside from the potentially low cost and lack of serious radioactivity, such explosives readily could be adapted to small inexpensive containment vessels and in a different fashion their energy release could be harnessed not only for electrical power production, but efficient heat production as well, plus having the same function of a nuclear breeder reactor where the explosive could produce as much tritium as it uses - making the nuclear cost essentially a function of the process used to recover the tritium produced; intrinsically simpler and cheaper than processing plutonium in breeder reactors.
"In recent years a new class of chemical explosives, which do not behave like normal explosives, have been under development. These promise to provide much higher concentrations of energy in small volumes than regular high explosives. This process, based on so-called ballotechnic technology, involves subjecting certain materials to high pressure shock compression, resulting in chemical reactions which give rise to those high energy concentrations. Based on statements coming from Russia, which unlike the U.S. has been quite open about their nuclear development program (ours effectively has ceased), there are reasons to believe this technology can be used to ignite very small quantities of deuterium and tritium to produce, in effect, a mini neutron bomb. As for the size and weight of the explosive, the potential exists for far smaller and lighter devices than nuclear explosives developed to date. For such a device, the energy partition is practically the converse of what happens in a fission explosive. Instead of most of the energy going into physical effects, as was the case for the bombs that destroyed Hiroshima and Nagasaki and for the Pacer explosives, the great bulk, about 85%, is released in the form of very high energy neutrons. For a burst of such a device in a relatively low density medium and for a 10 ton TNT equivalent yield, the blast component of such an explosion would be only about 1 ton (0.001 KT). To contain such an explosion underground would require a reinforced sphere approximately 10 meters in diameter and some tens of meters deep. In between bursts, the explosives, which might weigh on the order of pounds, would be lowered into the center of the cavity. Getting into qualitative specifics (and keep in mind that this discussion is not based on detailed calculations, for all the obvious reasons, but rather to present the general nature of the system), the chamber would be filled with carbon dioxide gas at very high pressure. Also in the chamber at the time of burst would be a vapor of an appropriate lithium (specifically lithium-6) compound - say lithium nitrate, which vaporizes at low temperatures.
"The purpose of the carbon dioxide is to slow down and absorb the energy of the neutrons emitted by the burst, but not to absorb the neutrons. The absorption of the reduced energy neutrons will be principally in the lithium, which has a very high propensity for such absorption and which will result in the production of helium and tritium. In effect, this scheme is analogous to how tritium normally is made, through neutron absorption in a fission reactor, except that it can be more cheap and efficient.
"At a much greater frequency than Pacer, the pure-fusion device would be lowered into the chamber and detonated. The hot gas would be piped out of the chamber and through a heat exchanger to produce steam, which in turn would drive a turbogenerator to produce electricity. Or the gas could be used to heat up large volumes of water, which could be dispatched to residential or industrial areas for heating purposes - as a substitute for natural gas, oil and electricity. (With respect to the explosive yield, there is nothing specific about the 10 tons TNT equivalent used here as an example. It readily could be tens of tons, the limitation on yield being a function of the cost of the containment problem, plus the political tolerance of explosions, however safe they may be, that take place in the vicinity of the areas where the energy is to be used. But for now this is a matter of conjecture, since we are discussing a scheme which has never received public and political scrutiny.) "For technically unsupportable reasons, but reasons that cannot be dismissed in the real world where nuclear fission power has been rejected by millions of Americans, producing power with fission reactors hardly has been an economic bonanza. To be sure, nuclear power generation has proved to be cheaper than coal and natural gas, but not all that much - on the order of 30 to 50 percent. (However, this has to be tempered when we consider the number of facilities that have been closed down or not even opened after construction has been completed.) Now this difference between nuclear and chemical power production still is quite significant when one calculates relative costs over long periods of time - i.e., decades - where the cost differential can amount to hundreds of billions of dollars, to say nothing of the difference in atmospheric pollution. This is a huge sum of money, comparable to the taxpayers' money wasted by the S&L bailout.
"On the other hand, who can predict how many nuclear power plant closings will occur to erode or even reverse this difference? How many additional reactor closings will take place as the politics of radioactive waste disposal become more and more restrictive? There are no hard answers to these questions, but our experience so far, aided and abetted by environmentalist pressures on politicians, does not bode well for the future of fission power regardless of reactor design improvements which promise large improvements in safety and efficiency. Adding to this the utter impossibility of making accurate long-term economic predictions, there should be an increasing incentive to explore and promote new and different nuclear energy schemes. One such scheme should be the use of low-yield pure-fusion explosives.
"Is the U.S. seriously investigating this prospective? Of course not! Despite all the prospective advantages of this scheme, in terms of U.S. nuclear policy a nuclear explosive, regardless of its application, is still a nuclear explosive and can be used for peaceful and military applications. As Gertrude Stein might have put it, 'A bomb is a bomb is a bomb.' Even though pure-fusion explosives may not be covered by the NPT, there still would be an outcry by nuclear arms control advocates that such a development, as peaceful and harmless as it may be, still is a threat to mankind. Despite the NPT avowal that peaceful applications of the Atom are an inalienable right, this right will be challenged, in the name of peace. But then the same thing might have been said when Alfred Nobel, of the Nobel Peace Prize, invented dynamite, which has been used to dig canals, mine ores, etc. - and blow people and cities to smithereens. Even though these devices used as mini neutron bombs in wars would allow a far more moral prosecution (by both sides) of war than high explosive weapons, U.S. policy still regards all battlefield nuclear weapons as basically immoral and to a degree where our stockpile of these weapons, including neutron bombs, is being demolished. So, to repeat, don't expect the U.S. government to take this scheme seriously, at least for the time being.
"On the other hand, although we do not take nuclear weapon development seriously any more, we do have a right to conduct research and even testing of the device discussed here. So does any other nation, and it is quite possible that any other number of nations may be working on pure-fusion explosives whose testing cannot be detected and identified from outside the country. Nor would the preparation of a test site be observable by any technical intelligence, since the required facilities are so modest in size and preparation. But apart from what other nations may be up to, we should at least give thought to such a scheme and its economic promise. Not to do so would be negligent and even foolhardy, considering our mounting energy problems.
"A few years ago when claims were made by two respected scientists that a 'cold fusion' experiment had been successful, the world went into a frenzy of excitement. But that turned out to be inaccurate, and the world felt terribly let down that the Promised Land of cheap and safe nuclear energy hadn't been reached. For decades before that, and still going on, there had been a massive (and massively expensive) program going on at various laboratories to develop techniques for 'hot fusion' energy produced without nuclear explosions. So obviously what seems to bother our government and millions of Ameri-cans is that there's nothing really wrong with cheap, clean nuclear energy provided it doesn't come from a bang, no matter how small. Are there any rational answers to this irrational dilemma? Perhaps, but they haven't emerged so far and they're not very likely to; for that would call for irrational people becoming rational.'' Correspondence with Sam Cohen can be addressed to him at 13241 Riviera Ranch Rd., Los Angeles, CA 90049.
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Vol. 21, No. 4
Newsletter: Access to Energy Newsletter Archive Volume: Issues Issue/No.: Vol. 21, No. 4 Date: December 01, 1993 10:05 AM Title: Dollars and Nonsense
Copyright © 2004 - Access to Energy Newsletter Archive
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