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Response to Judi Lynn (Original post)

Sat May 12, 2018, 10:38 AM

10. My hope is that in a future time, this plutonium will have real value. Bomb cores based...

Last edited Sat May 12, 2018, 03:29 PM - Edit history (1)

...on weapons grade plutonium have problematic stability, because while they have very low levels of Pu-240 compared to reactor grade plutonium, they do have some of this isotope, and it both releases neutrons through a high spontaneous fission rate and a higher alpha rate. Although Pu-239 has a long half-life, it also exhibits alpha decay.

Neutrons released can cause small (subcritical) fission events as well.

I've seen TEMs of old plutonium, and they exhibit pitting both from radiation damage and inclusions of helium and a few fission products.

This was a rationale for continued nuclear weapons testing at the Nevada test site, where weapons were tested underground. The weapons scientists were interested in stability of cores that had been stored for a long time. Happily, such testing finally stopped, way too late, but it stopped, although it's possible the orange clown or someone equally as criminal and venal and foolish could always restart it, much as Trump's pal Kim Jung-Un has tested them.

In nuclear weapons, plutonium is always present in the form of a gallium alloy designed to stabilize the delta phase, a phase covering a relatively small region of the phase diagram.

The alpha, beta, gamma and epsilon phases of plutonium are not suitable for the very precise compression (by shock wave) required to detonate a nuclear explosion.

In order to achieve nuclear disarmament, we must degrade the plutonium in these weapons in order to render it into a form that will generate too much heat to be utilized in weapons, what I call the "Kessler solution." (Kessler et al. Nuclear Engineering and Design 238 (2008) 34293444).

In more than 30 years of study of environmental issues, I have convinced myself that the only form of environmentally sustainable source of energy for humanity is the uranium/plutonium cycle. I know of course, that this is not immediately popular, but we live in exceedingly stupid times where fear and ignorance are celebrated rather than suppressed.)

Bomb cores are metallic.

All of my reactor thinking in the last 5 years or so has involved reviving the LAMPRE concept in light of huge advances in materials science in the last 50 years since the LAMPRE was foolishly de-funded and forgotten. Although this reactor, which operated about two years with a very small core (see below) that produced about 1 MW of power relied on an iron/plutonium eutectic and a ternary cobalt cerium plutonium eutectic was investigated but never brought to criticality, I am intrigued by the neptunium plutonium eutectic shown in the phase diagram above. Bomb grade plutonium liquefied via its eutectic with neptunium would be rapidly rendered permanently unusable for weapons via the formation of 238Pu which result in the generation of too much heat (and radiation) to allow for the assembly of weapons.

My guess is that a complication for this approach might be the gallium in the cores, although I have been unable to locate a published ternary gallium neptunium plutonium phase diagram as yet.

Just this week though, going through some actinide phase diagrams as I sometimes do when I have time, I finally came upon a fine idea of extracting gallium from bomb cores without oxidizing them to an inorganic compound, that is removing the gallium (which is a critical metal in any case with lots of non-nuclear applications) directly in the liquid phase. This would involve metallic extractions in the liquid phase with a fission product that would be readily available in a more sensible world than the one in which we actually live, one in which the inexhaustible supply of uranium placed into the plutonium cycle were providing almost all of our energy.

Tip of the hat to my friend Mark at Atomic Skies, a nuclear historian, from whose site, linked above, comes this picture of the LAMPRE core:


(You need to click on the link to see it.)

Have a nice weekend.

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Arrow 12 replies Author Time Post
Judi Lynn May 2018 OP
pangaia May 2018 #1
rzemanfl May 2018 #2
KY_EnviroGuy May 2018 #3
DetroitLegalBeagle May 2018 #5
KY_EnviroGuy May 2018 #6
Crash2Parties May 2018 #9
karynnj May 2018 #4
Anon-C May 2018 #7
keithbvadu2 May 2018 #8
LineNew Reply My hope is that in a future time, this plutonium will have real value. Bomb cores based...
NNadir May 2018 #10
John ONeill May 2018 #11
NNadir May 2018 #12
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