Today, the New York Times confirmed our concerns about spent fuel at the crippled Japanese reactors.Spent fuel is the biggest potential hazard in this nuclear crisis.
Figures provided by Tokyo Electric Power on Thursday show that most of the dangerous uranium at the power plant is actually in the spent fuel rods, not the reactor cores themselves. The electric utility said that a total of 11,195 spent fuel rod assemblies were stored at the site.
That is in addition to 400 to 600 fuel rod assemblies that had been in active service in each of the three troubled reactors. In other words, the vast majority of the fuel assemblies at the troubled reactors are in the storage pools, not the reactors.
The Times story confirms the interpretation that spent fuel was tightly packed at the site to save space and money. Moreover, it confirms concerns that plutonium in mixed-oxides fuels could be released if reactor 3 melts down.
One big worry for Japanese officials is that reactor No. 3, the main target of the helicopters and water cannons on Thursday, uses a new and different fuel. It uses mixed oxides, or mox, which contains a mixture of uranium and plutonium, and can produce a more dangerous radioactive plume if scattered by fire or explosions.
I don't have time to write a full diary now. I will revisit this story later. This information confirms many of inferences I made in the diary I wrote yesterday.
Updated by FishOutofWater at Thu Mar 17, 2011 at 08:39 PM EDT
The Union of Concerned Scientists has compiled a different set of numbers than the Times. The UCS table shows a large amount of spent fuel stored at shut down reactors 4, 5 and 6. The total inventory of spent fuel rods is less in the UCS numbers than the Times numbers, but it is still a huge inventory of radionuclides.
Figure corrected bu UCS: