-------------------------------------------(UPDATE on 8/29/2011: NISA backtracked in the joint conference (TEPCO/government) in the afternoon, and now says it's not sure about the conversion rate of neptunium-239 into plutonium-239.)
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Now this is very curious.
The Nuclear and Industrial Safety Agency (NISA)'s daily press conference is ongoing (August 29). The NISA spokesman Moriyama mentions neptunium-239's conversion ratio to plutonium-239 as 1 to 1.
According to the June 6 estimate by the NISA:
Plutonium-239: 3.2×10^9
Neptunium-239: 7.6×10^13
So, now it is:
Plutonium-239: 7.6 x 10^13, or 76,000,000,000,000 or 76 terabecquerels
The amount of plutonium-239 has increased 23,000-fold, according to NISA.
On August 15 I wrote about neptunium-239, half life of about 2 days, having been detected in large quantity in Iitate-mura, 35 kilometers from Fukushima I Nuclear Power Plant. I had to take down the second post on the subject, but the information was correct.
Now, NISA is suddenly mentioning neptunium-239. Admission of wide dispersion of this nuclide and resultant plutonium-239 may be finally forthcoming, after more than 5 months.