JNES Calculation of the Amount of Radioactive Materials Released from #Fukushima I Nuke Plant

Japan Nuclear Energy Safety Organization (JNES), an independent administrative corporation under the Ministry of Economy, Trade and Industry, issued the result of its calculation of radioactive amounts released from Fukushima I Nuclear Power Plant in the first week of the nuclear accident.

From JNES presentation (3/27/2013), unit is petabecquerel (1x10^15) and 1 petabecquerel is 1,000 terabecquerels:

From March 11 to March 17, 2011,

I-131: 250 to 340 petabecquerels (or 250,000 to 340,000 terabecquerels)
Cs-134: 8.3 to 15 petabecquerels (or 8,300 to 15,000 terabecquerels)
Cs-137: 7.3 to 13 petabecquerels (or 7,300 to 13,000 terabecquerels)

For I-131, JNES's calculation, which is based on the accident progress analysis, is closest to TEPCO's number which is the highest (500 petabecquerels, or 500,000 terabecquerels).

In the image below (English labels added by me), from the top row, the entities that did the analysis are:

• Japan Nuclear Energy Safety Organization (JNES)

• TEPCO

• Japan Atomic Energy Agency (JAEA)

• Japan Agency for Marine-Earth Science and Technology (JAMSTEC)

• Central Research Institute of Electric Power Industry (CRIEPI)

All except JNES based their calculation on the actual measurement of radioactive materials.

I find it interesting that JNES's calculation shows potentially more Cs-134 than Cs-137. From the actual measurements on the ground, I believe the ratio has been 1:1 to 1:1.2.

On the night of March 11, 2011, the now-defunct Nuclear and Industrial Safety Agency (NISA) had JNES do the simulation using the Emergency Response Support System (ERSS) to predict the progression of the accident. JNES faxed the result of the simulation for Reactor 2 to NISA as early as 9PM on March 11, the simulation for Reactor 1 by noon on March 12 (more than three hours before the explosion), and the simulation for Reactor 3 at 6:30AM on March 13. The faxed results for Reactor 2 was delivered to the Prime Minister's Official Residence just past midnight on March 11 (early hours of March 12). (Jiji Tsushin, 9/3/2011)

No one acted on them.

NISA was trying to figure out the areas to have people evacuate. In addition to ERSS, the agency also ordered SPEEDI simulations done, using the information that the agency collected on its own. The agency dropped that effort when Prime Minister Kan and his ministers thought they knew best and drew concentric circles around the plant and decided the evacuation zones, ignoring the emergency protocol that specifically said they should use SPEEDI simulations for that purpose. (Asahi Shinbun's "Trap of Prometeus" Part 2)

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