The Nuclear Materials In The Ebisawa Indictment

The US Department of Justice issued a superseding indictment against Takeshi Ebisawa, a leader in the Yakuza international organized crime syndicate. Ebisawa was already charged with narcotics and weapons trafficing. Now nuclear materials trafficking has been added to the charges.

Ebisawa offered an undercover agent representing himself as an intermediary for an Iranian general samples of what he said was a large amount of thorium, uranium, and plutonium in exchange for weapons including surface-to-air missiles. The fissile material was said to come from Burma, the destination of the weapons.

All the nuclear material trafficking cases I’m aware of involve small amounts of the material, presented as a sample of more that is stored somewhere. Except that “more” is nonexistent. This case seems to follow that pattern.

My questions are

• Did the trafficker seem knowledgeable about the material?
• Do the LE people seem knowledgeable about the material?
• How much material was in the sample, and in what state was it?
• Where did it come from?

The first two are mainly a credibility check on the rest of the story. My answers to those two questions are not really and yes, although I think the SDNY presentation of the information verges on the sensational.

The biggest indicator that Ebisawa didn’t really know what he was selling was the attempt to sell thorium for nuclear weapons. He may have known that thorium cannot be used, but uranium-233, which is fissile, can be made from thorium-232, which is the bulk of natural thorium. The thorium must be irradiated in a reactor to produce uranium-233, and a byproduct is uranium-232, which has a strong gamma ray, making handling more difficult than plutonium. The reactor fuel must be processed chemically to obtain the uranium-233.

Likewise, yellowcake (only 80% purity according to the indictment) requires a great deal of chemical processing, including isotopic enrichment, before it is usable in a bomb. According to the indictment,  the undercover agent asked Ebisawa to make sure that the yellowcake is sufficiently enriched for a weapon, and Ebisawa says he will check Although uranium would be converted to the oxide as one of many steps after enrichment, the 80% (presumably chemical) purity indicates that this yellowcake is not at that stage. Ebisawa seems unaware of this.

Ebisawa didn’t know what he had, but he might have passed it off to someone who knew even less.

How much material was in the sample, and what state was it in?

There seem to have been three or four samples: a black granular material, and yellow powders. The yellow powders were said to be yellowcake and Th-232. Thorium dioxide may be white or yellow, so it’s possible that the powder is what they say.

Although a radiation meter is included in the photos, it’s not clear what it’s measuring. The radiation meter is a Gamma-Scout (h/t to @sandalphon.bsky.social for identifying it!). It’s suitable for rough measurements, but not a precision instrument. We are not told the units for the numbers, but the different positions of the top lever in the two photos suggest measurements on two different scales.

Two photos show a black material. All of the photos have little detail. It’s not possible to tell whether the black material is the same in the two photos. The second photo shows one larger pebble and many smaller ones, some with a cubic structure.

A U.S. nuclear forensic laboratory examined the Nuclear Samples and determined that both samples contain detectable quantities of uranium, thorium, and plutonium.  In particular, the laboratory determined that the isotope composition of the plutonium found in the Nuclear Samples is weapons-grade, meaning that the plutonium, if produced in sufficient quantities, would be suitable for use in a nuclear weapon. 

It’s not clear which samples contain which elements. To call the amounts “detectible” implies that they could be very small indeed; radiation makes all these elements easy to detect. The isotopic composition of plutonium could also be determined even if the quantities are very small. It’s likely that the laboratory did other measurements to determine what else is in the black material, which I am extremely curious about. It could be something natural, like monazite sands, which contain thorium, or it could be something literally cooked up. It resembles nothing in the normal processing stages for nuclear weapons.

Small plutonium sources might be obtained in various ways. When I was working in Estonia, they were fairly common at the Paldiski nuclear submarine training station. Most sources have been picked up by governmental agencies by now, but it would not be surprising to find one. China, India, and Pakistan could also be sources.

 “Weapons-grade” plutonium refers to its isotopic composition. All plutonium can be made into nuclear weapons, but it’s easier to do with weapons-grade composition. Note the qualification in the Justice Department statement: “if produced in sufficient quantities.” My general sense is that the amount was very small indeed, milligrams at the most.

The barrels shown in one photo could be anything, including, most likely, empty.

Where did it come from?

During their discussions regarding EBISAWA’s access to nuclear materials, EBISAWA also engaged with UC-1 [the undercover agent] concerning EBISAWA’s desire to purchase military-grade weapons.  To that end, in May 2021, EBISAWA sent UC-1 a list of weapons, including surface-to-air missiles, that EBISAWA wished to purchase from UC-1 on behalf of the leader of an ethnic insurgent group in Burma (“CC-1”).  Together with two other co-conspirators (“CC-2” and “CC-3”), EBISAWA proposed to UC-1 that CC-1 sell uranium to the General, through EBISAWA, to fund CC-1’s weapons purchase.  On a February 4, 2022 videoconference, CC-2 told UC-1 that CC-1 had available more than 2,000 kilograms of Thorium-232 and more than 100 kilograms of uranium in the compound U3O8 — referring to a compound of uranium commonly found in the uranium concentrate powder known as “yellowcake” — and that CC-1 could produce as much as five tons of nuclear materials in Burma.  [emphasis added]

Burma (Myanmar) has been suspected of desiring nuclear weapons in the past. However it has no mining or milling that might produce yellowcake, and earlier claims of attempts to develop a nuclear weapons capability are thin. NTI has an excellent review.

The small seal to the left in one photo is the seal of Thailand’s Office of Atoms for Peace. Thailand is where the material was confiscated.

My reading is that Ebisawa was trying to con the person he thought represented Iran into a shipment of weapons in exchange for materials he likely got from someone else with some assurances they looked enough like what he claimed to con a rube. He likely would not have fared well if he had actually been negotiating with an Iranian representative. Iran has a nuclear program and can make the measurements that would tell them the material is of little to no value. And Iran is not working on a uranium-233 weapon. Nobody is.

Cross-posted to Nuclear Diner