Talk:Plutonium

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Paramagnetism

   Someone whose exotic-magnetism chops are less rusty than mine should express an opinion as to whether Study confirms, Plutonium has no Magnetism (currently cited under Science, but no subheading, on Google News) and/or other new Google hits indeed require updating our coverage on the accompanying article, which appears to me be satisfied (as of an unrelated edit an hour ago) with "Magnetic ordering [is] paramagnetic" (in the InfoBox) as the only magnetism-relevant fact.
   It also makes me wonder if the new result suggests the paramagnetism would extinguish at temperatures sufficiently low that thermal noise is lower than energy-level differences anomalously close between states differing (i presume) in more than a single quantum number ....? (I'd bet there are at least some editors who have a better idea than i about which related but more general quantum-magnetism topics are likely to have been edited by the most suitable editors for the task.)
--Jerzy•t 07:51 & 07:56, 15 July 2015 (UTC)

"...most of whom were industrial workers..."

WHAT THE FUCK DOES THIS HAVE TO DO WITH ANYTHING??? 70.29.99.120 (talk) 08:28, 8 July 2018 (UTC)

You are right. Allcaps is in place, even. I have deleted that phrase. -DePiep (talk) 21:49, 8 July 2018 (UTC)

Criticality potential

Plutonium in solution is more likely to form a critical mass than the solid form due to moderation by the hydrogen in water.[10]

Umm i think this is misstated. Believe this should say "LESS" likely to form critical mass when moderated as an aqueous solution vs a solid. — Preceding unsigned comment added by 69.113.58.160 (talk) 16:22, 5 November 2018 (UTC)

Plutonium in Solution, and Neutron Moderation

The assumption that a solution of a plutonium compound must be aqueous is no longer valid. The phrase "plutonium in solution" needs to become "plutonium in aqueous solution".
In a molten salt reactor, plutonium would be dissolved as a tetra- or hexa- fluoride or -chloride, in a very hot molten alkali fluoride or chloride as the solvent.
Neutron moderation makes a huge difference to the idea of "critical mass". Neutrons at thermal speeds are much more easily captured than fast ones. Carbon nuclei and hydrogen nuclei are quite good at taking energy from neutrons.

In his book "Surely you're joking, Mr. Feynman" Richard Feynman does indeed point out the danger that aqueous solutions of fissile actinides - in this instance enriched uranium nitrates - can far more easily attain critical mass than the same amount of solid oxide or metal. Two containers of aqueous solution separated by a wall could add up to a critical mass with moderated neutrons!

The danger to personnel is from the neutrons, not necessarily an explosion. Bombs are usually made with isotopically pure fissile metal. But a reactor can use a mere 3.6% of the fissile isotope, as pellets in zirconium cylinders, surrounded by water to moderate the neutrons. The plutonium production reactors used natural metallic uranium, carbon in the form of very pure graphite, and water as a coolant, to create a state of "criticality" enough for the fission-produced neutrons from fissile 235_U, which is only 0.7% of the uranium, to be slowed down enough to be captured by other fissile nuclei in a chain reaction stable and productive enough to provide extra neutrons to be captured by the 238_U and produce ultimately 239_Pu. Carbon nuclei are quite good neutron moderators, and do not capture neutrons as much as hydrogen nuclei, protons, do. DaveyHume (talk) 15:42, 10 January 2019 (UTC)