In 2010, “Japan had more than 46 tons (8.7 Tons in Japan, approximately 37 tons in Europe) of separated plutonium in stock, but its MOX recycling program has made little progress.” (Suzuki, 2010). 46 tons of plutonium equals to 41,730 kilograms.
Argonne National Laboratory reports that the US stockpiled about 110,000 kilograms (kg) of plutonium between 1944 and 1994, and about 100,000 kg remains in inventory. http://www.evs.anl.gov/pub/doc/Plutonium.pdf
Majia here: So Japan has stockpiles of plutonium that are about 40% of the US stockpiles.
Keep in mind this figure for Japan is the official number. Japan may have more given its stockpiling craze. (see my links at the bottom of this post for background)
Japan has a major fuel storage problem and spent fuel management purportedly has been a driver in Japan’s reprocessing requirements, according to Suzuki who contributed a chapter on Japan’s plutonium breeder program to Fast Breeder Reactor Programs: History and Status: A research report of the International Panel on Fissile Materials,.
Majia here: So Japan had a lot of spent fuel and it had a lot of plutonium stored in Japan.
It is now being widely recognized that the amount of plutonium stored around Japan is at problematic levels.
Yet, Japan wants to keep on processing plutonium and convened a secret panel to authorize it within its government (see my blog posts linked at bottom of essay).
Piers Williamson summarizes a speech given May 31st, 2012 by Professors Frank von Hippel (Princeton University) and Gordon MacKerron (University of Sussex) on the issues associated with reprocessing and stockpiling this volume of enriched fuel.
Williamson's summary is published as “Plutonium and Japan’s Nuclear Waste Problem: International Scientists Call for an End to Plutonium Reprocessing and Closing the Rokkasho Plant” and appeared in the Asia Pacific journal.
Williamson notes academics like von Hippel are claiming that Japan has a credibility problem when it comes to its unwillingness to stop enriching plutonium (I posted on this yesterday http://majiasblog.blogspot.com/2012/06/more-on-japans-efforts-to-resume.html).
Williamson notes that it would be very easy for Japan to quickly assemble nuclear weapons.
Majia here: No doubt Japan has a just-in-times nuclear weapons program. Think about it: why would Japan need to actually assemble the weapons before they are needed when it is so much more efficient to simply build them with vital parts stored strategically for that very purpose.
Of course, Japan may actually have hidden nuclear weapons; but I’m betting on just-in-time.
The Japanese have that system down.
So, why is this relevant for the Fukushima disaster?
The problem is that storing plutonium is dangerous. Plutonium is very dangerous stuff. One alpha particle emitted from Plutonium can break your DNA. It is a very bad thing to have an alpha particle lodged in your body.
(See http://majiasblog.blogspot.com/2012/05/on-internal-emitters.html and this post here for a discussion of what happened when people started ingesting radium in the US, which is less radiotoxic than plutonium. http://majiasblog.blogspot.com/2012/05/interesting-tidbits-in-history-of.html)
Japan had a lot of plutonium that was vaporized given it is being detected all around the northern hemisphere, including Lithuania.
The thing is we don’t know how much plutonium was vaporized.
It was surely quite a bit.
The range for Mox assemblies believed to have been inside reactor 3 range from 164 assemblies to 32 mox assemblies. At the low end estimate of 32 mox assemblies, we still get a scary total of 5.5 tons of fuel containing more than 300 kg of plutonium.
“300 kg is therefore equivalent to 300 billion lethal doses” (MOX fuel-Corium-Plutonium in Fukushima Daiichi http://www.fukushima311watchdogs.org/biblio/9/Mox%20fuel-corium-plutonium%20in%20Fukushima%20Daiichi.pdf)
So, at the very low end of risk, up to 300 kilograms of fuel may have been vaporized from the reactor alone. (The article's authors actually felt far more plutonium was involved).
A critic might say, "we don’t know how much of the assemblies were actually vaporized. So, 300 kilograms is an unlikely figure and 300 billion lethal doses absurd."
And there are all sorts of random variables impacting dispersal and we really don’t know how much of the fuel in reactor 3 is still intact, particularly because it has been burning and steaming for the last 15 months, as evident on the Tepco webcam and in screen shots I’ve taken.
That said, we must also consider that we don’t know whether mixed oxide fuel was stored in any of the spent fuel pools or whether there might even have been separated plutonium stored at the site.
I certainly would not take Tepco's word at face value on the subject of fuel stored at the site.
That raises the question: Where does Japan store all of its plutonium? Where do you store 8.7 tons of separated plutonium?
Plutonium was produced at the Tokai complex. It is probably stored there.http://majiasblog.blogspot.com/2012/05/tokai.html
Tokai is a huge complex and they’ve been processing fuel there for a while. See background on Japan’s reprocessing http://www.jaea.go.jp/english/04/tokai-cycle/01.htm
Tokai had earthquake damaged and has had reports of radioactive water leaking and a fire.
Japan had a lot of mixed oxide fuel in Daiichi unit 3’s reactor. Japan may have had mixed oxide fuel stored on site as well. Japan could have even had separated plutonium on site. Some of that fuel was damaged in March of 2011 and the plant has been steaming and smoking ever since.
Lots of plutonium may have been vaporized.
Plutonium may have been vaporized at other locations as well.
Japan’s crisis may very well have led to the greatest atmospheric and ocean dispersal of plutonium ever. (I will have to see how much was projected as being dispersed by Chernobyl but Chernobyl used U-235 not plutonium-infused mox fuel).
Inhaling or ingesting plutonium is more than simply increasing our background gamma. Plutonium emits high energy atoms that are capable of breaking DNA and can do terrible things to bodies when lodged inside them.
This is the real threat I believe from Fukushima.
SOURCE DETAILS (NOT LINKED IN TEXT OF ESSAY)
Piers Williamson Japan’s Nuclear Waste Problem: International Scientists Call for an End to Plutonium Reprocessing and Closing the Rokkasho Plant. The Asia-Pacific Journal: Japan Focus, Vol 10, Issue 24, No 4, on June 11, 2012.
Suzuki, Tatsujiro. Japan’s Plutonium Breeder Reactor and its Fuel Cycle. In Thomas B. Cochran, Harold A. Feiveson, Walt Patterson, Gennadi Pshakin, M.V. Ramana, Mycle Schneider, Tatsujiro Suzuki, Frank von Hippel Fast Breeder Reactor Programs: History and Status: A research report of the International Panel on Fissile Materials (53-61). February 2010. http://fissilematerials.org/library/rr08.pdf