For sure it was MOX on Units 3 and 4.
Fukushima DaiIchi Reactor 3, had a history of cover ups on reactor vessel integrity, but several years prior to 311, they changed the shroud on F3 to be "new" but also to accommodate higher energy from MOX. That reactor blew sky high on video, see links below.
The reason GE was on site (they Scramed as fast as they could) was that they had removed a hot load of active fuel from 4, they had a fresh load of MOX in the equipment pool, and they were changing the shroud on F4. The goal was to partly change out the fuel in F4 to MOX even the complete burnup cycle wasn't done. This left partly spent fuel and new MOX in the same place. Of course by now the gov stopped all video release so we never got to see Fuku 4 blow sky high like 3, but look at the post explosion building pictures.
Fukushima DaiIchi (just means number 1, Fukushima means Island of Dreams) unit 3 and 4 blew up in a nuclear type of explosion called a Prompt Moderated Criticality. It is a runaway neutron event with a massive release of energy usually in milliseconds, which is the presence of water also becomes a steam bomb which amplifies the explosive force due the volume expansion during phase change from liquid to vapor.
More information on the amount of radiation (the inventory) blown into the atmosphere, and background information of the Prompt Moderated Criticality (with a video showing its not just theory but fact by Argonne National laboratory) are here:
A troll had this to say: "Bryan Elliot"
Fukushima could happen 150 times over and still move the Pacific's radioactivity by a factor of less than 1%. If we're doing a "great job" killing it, I'd hate to see what you consider a "bad job".Hmmmm....I guess in light of the coverups, the lies, the struggling bronto nuclear industry, the mass ocean dieoffs......we might as well assume that "you can't prove it's Fukushima" so therefore you could blow up all the nuclear plants in Japan and USA (about 150) and everything would be hunky dory. As least per the troll....things should work out just fine.
a) It's in the noise
b) Our measurement devices are so good, thats why we are seeing it