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MIT and the Challenge of Energy

Tanachai Limpaitoon, a PhD candidate at MIT, is thinking out loud about America's energy challenges, and what part his university can play in helping to solve them:
Obviously, we all understand the risks that accompany too great a dependence on foreign energy, particularly from politically unstable parts of the world. We also need to secure extended energy delivery systems, which are vulnerable to disruption, whether from sabotage or natural disasters. We must remember that major wars have been fought over access to scarce resources, and our dependence on oil for transport means growing prospects for conflict over energy supply. And while there is a renewed interest in nuclear power as an alternative to carbon-based fuels, we must answer the questions about the consequent potential for the proliferation of nuclear weapons.
Plenty of food for thought, though I hope Tanachai is taking a close look at GNEP as a long-term answer to his question.

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I hope he considers the fact that it is nearly impossible if not impossible for a proliferator to divert the fuel cycle as it currently stands to weapons production, and that nothing but a uniquely specialized Pu-239 production reactor can produce bomb-grade plutonium.
Anonymous said…
Two important technical errors. 1) A power reactor can produce weapons-grade plutonium if the fuel is irradiated briefly enough. More important, 2) plutonium need not be weapons grade (> 90% Pu-239) to be used in a nuclear explosive. Or at least that's the position of the US DOE, and they're the folks who make them. And used to test them.

Is it the US industry's position that plutonium with less than 90% Pu-239 cannot be used to make a nuclear explosive device?
Paul Primavera said…

I do not know if what you write is correct, but weapons-grade plutonium must contain no more than 7% Pu-240. I would assume this means that the other 93% must be Pu-239. I do not know if the other 93% can be a mixture of U-233 or 235 and Pu-239. I got this information from:

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I would greatly prefer that all weapons grade plutonium and uranium be down-blended for use in commercial nuclear reactors, saving only the minimum necessary for asteroid deflection:

"Three-stage thermonuclear devices have also been developed, whereby a third, larger fusion stage (a 'tertiary') is compressed by the energy of the fusion 'secondary' (described above). A three-stage bomb, the Mk 41, was deployed by the United States, and the USSR’s Tsar Bomba was also a three stage weapon. In theory, there is no limit to how many stages could be added. Though there is currently no need for five- or six-stage weapons with yields that could approach a gigaton, they could possibly be of use in deflecting Near-Earth Objects such as Asteroids and Comets which are in danger of colliding with the Earth and large enough to do sigificant damage (have high Torino Scale values)."
Robert Merkel said…
Anonymous is right.

WRT reactor-grade plutonium, I am not a nuclear physicist but I've read studies that claim that while reactor-grade plutonium is not ideal for making the kind of bombs that a first-world military would expect, it's quite adequate for making something that would explode with around 1 kiloton of force, even if the bomb was no more sophisticated than Trinity. That's enough to kill many thousands of people if you let it off in a densely populated city, with a lethal blast and radiation dose radius of roughly half a mile.

Interestingly, the same seems to apply (but to a lesser extent) to modern "bomb-grade" plutonium, which is not the super high purity stuff used in WWII. It would, apparently, be quite difficult to get Trinity-level yields out of the stuff reliably without using boosting. If you were talking about a nation-state with significant technical resources, they could probably use a boosted fission design to get much bigger yields (though that's apparently much more difficult to get right).

So spent fuel rods are a proliferation risk, though luckily they are so radioactive that they're damn near impossible for a terrorist to steal without immediately incapacitating and killing himself in the process, let alone reprocess into plutonium for a weapon.
Paul Primavera said…
Thanks for the clarification, Robert.

I don't mean to be sarcastic, but to put things into perspective, I would imagine that even as spent fuel rods are a 'proliferation risk' with respect to fission weapons, gasoline is a 'proliferation risk' with respect to napalm.

Spent fuel rods that are "so radioactive that they're damn near impossible for a terrorist to steal without immediately incapacitating and killing himself in the process, let alone reprocess into plutonium for a weapon" are indeed of minimal if any 'proliferation risk'.

But when reprocessed using the UREX process, they can be used to fuel the next generation of reactors.

Now let's see what industries wouldn't want the eventual development of a closed cycle, self-sustaining, clean nuclear energy future for the United States? Coal perhaps? Natural Gas?

And what has killed far more people (sometimes quite explosively)? Coal perhaps? Natural Gas?
Anonymous said…
Sorry, but I'm not prepared to accept a Wikipedia entry over the informed opinion of DOE and US nuclear weapons labs that so-called fuel and reactor grade Pu can be used to make effective, reliable nuclear explosives.

This was also the conclusion of the National Academy of Sciences in their 1994 and 1994 studies on options to dispose of surplus weapons grade Pu. And of the US DOE in its 1997 nonproliferation assessment of the surplus Pu disposition program.
Jim Hopf said…
You're all missing the main point.

Even if it is possible to get a low-yield nuclear explosion from spent fuel plutonium, it remains true that spent fuel (especially spent fuel in the developed world) does NOT represent a significant proliferation risk. The plutonium problem, if true, was always just the icing on the cake.

The reason spent fuel does not represent a real proliferation risk is that it is no more useful than raw uranium ore, which all these countries (Iran, etc...) have in abundance right under their own feet, in their own soil. Handling and processing spent fuel, and extracting the plutonium, is at least as difficult, if not more, than simply mining and enrichming raw uranium ore.

As a final note, stealing spent fuel from US (or developed country) nuclear power plant, then getting away, and then processing out the plutonium is absurdly difficult, far more difficult than any other conceivable approach. It's farcial.

As evidence of this, consider what all these nations have done up till now, Iran being a case in point. Pakistan enriched their own fuel, and this is the main tack being taken by Iran.

It fuel cycle facilities, both front and back end, that need to be controlled. That is, enrichment and reprocessing facilities should only be allowed in trusted nations. Reactors, as well as spent fuel inventories, are much less of an issue. There is a growing consensus on this, in the IAEA and elsewhere. Hence fuel cycle facility control the proposals from Al-Baredai (IAEA) and Bush on this subject.

The proliferation risk of nuclear power use in the developing world can be greatly minimized with some intelligent, targeted policies (concerning fuel cycle facilities), like those discussed above.

Nuclear power use in the developed world (in countries that already have the bomb, etc..) simply does not represent any proliferation risk. Never has. This is especially true concerning simply adding some more reactors in countries that already have a large number of them. Not only is stealing spent fuel from a developed country implausible, but adding to a huge (already "infinite") spent fuel inventory will clearly have no effect.

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