Jerry Pournelle speaks out about Weapons Grade Plutonium

[Social Spit]

www.jerrypournelle.com/vi...l#Thursday



Thursday, April 10, 2003

The breaking news is Plutonium in a big underground facility at Iraq's nuclear research site.



The news is all about "weapons grade Plutonium" which will very likely turn out to be false, and not about the huge underground complex that Hans Blix and his ace inspectors never found; and the aftermath of the story will be that there wasn't any "weapons grade" Pu and therefore the war was needless.



I would say that hiding a large underground nuclear research facility from the UN inspectors was itself the big story, but that is likely to be lost in the noise over "weapons grade" Pu.



They say they found "Yellowcake" and it was more radioactive than it should be. "Yellowcake" is Uranium Oxide, and is a term often used for refined Uranium ore. It would then be sent to an enrichment plant. It will typically have a very low U235 content; enrichment will bring up the ratio of U235 (actively radioactive) to U238 (more or less nuclearly inert, "depleted"). If what was supposed to be Yellowcake is more "radioactive" than it should be, then we need to know more about "how much more" and what kind of radiation is given off. As you can see here:



U-238 Beta Decay Energy: B- -147.065 +- 1.145 keV



Mode of decay: Alpha to Th-234

Decay energy: 4.270 MeV





U-235 Beta Decay Energy: B- -123.716 +- 0.869 keV



Mode of decay: Alpha to Th-231

Decay energy: 4.679 MeV





Pu-239 Beta Decay Energy: B- -802.912 +- 2.011 keV



Mode of decay: Alpha to U-235

Decay energy: 5.245 MeV





The energies and decay properties should make it easy enough to see if there is Pu present, but without reasonably sophisticated tests, a larger proportion of U-235 than usual in Yellowcake can make it "more radioactive" than was supposed.



We will just have to wait and see, but I won't be terribly surprised if there was no "weapons grade" plutonium.



"Fuel grade" Uranium is on the order of 10% U-235 and is almost always in oxide form. "Weapons grade" Uranium is about 90% U-235 and is generally in metallic form. I don't know much about Pu. They did have some experimental Pu fuel rods at the San Onofre SCE nuclear plant some 30 years ago when I did an article on "America's Looming Power Crisis" and had access to (and toured) many power facilities in California, Nevada, and New Mexico, but I didn't note the composition at the time. I would presume "weapons grade" Plutonium to be about 90% metallic. Plutonium is exceedingly dangerous stuff to get inside you (it's not all that horrible if ingested, it's getting particles in the lungs that will kill you), and it's not likely to be around in Yellowcake.



However, when they said "Yellowcake" I assumed they meant Pu mixed with Uranium oxides. This can be the result of using Pu in a reactor. Pu is also a possible product of power fission processes (the amounts can be varied depending on geometries and other matters) but that will be contained in the fuel rods. Fuel rods before they go into the reactor are not dangerous. Once they have been in a reactor they are hideously dangerous.



Pu isn't all that violently radioactive -- that's why the half life is in tens of thousands of years -- and was thought not to occur naturally until a couple of decades ago a "natural reactor" -- a Uranium ore site with a geometry such that water could pool in it and serve as a moderator -- was found in, I believe Nigeria (certainly somewhere in sub-Saharan Africa). The natural reactor had been operating for thousands of years and had generated some Pu meaning that Pu has been found in "nature" and thus is not exclusively a "man - made" element like Californium.



I would be much surprised to find "weapons grade" plutonium in a research facility. But any Pu at all is interesting.



As I said, the real story is a large nuclear research facility underground and never seen by the weapons inspectors. Clearly it was hidden for what seemed good reasons to Saddam and Company.