Wednesday, May 9, 2012

Post 3: Unanswered Questions and Some Extrapolations Regarding Radiation at Fukushima

This is the third post in 3:

1. Post I:  Report Contains Numbers of Fuel Assemblies at Fukushima as of March 2010

2. Post II: How  Much Radiation Is At Issue: Cesium 137 in Spent Fuel Pool 4 

My Analysis:
Strangely missing from most public dialogue about the Fukushima Dai-ichi plant are any specific discussions of (a) reactor 3; (b) the common spent fuel pool, and (c) reactors 5 and 6. Also missing from public discussion are (d) quantifications of other forms of radionuclides that were released into the air and sea during the explosion. Most importantly, perhaps, is (e) the absence of any kind of discussion of the ongoing nature of the releases. I'm going to address unit 3 and the common spent fuel pool here.
            The exact state of reactor 3 is unknown but the physical appearance of the reactor is of utter destruction. Reactor 3 had the vigorous explosion and commentators have suggested that there was either a criticality in the reactor pressure vessel or in the spent fuel pool. Reactor 3 alone contained mox fuel, which uses plutonium in the fuel mix, rendering it more toxic than fuel based only on uranium (Reuters
          Using the data from the previous two posts linked above I am going to make some extrapolations about the cesium-137 radiation in spent fuel pool #3 and the common spent fuel pool.

What We Know About Cesium-137 in Fuel Pool 4

Professor Koide claimed the following: 1331 assemblies = 5000 X as much cesium-137 as released by Hiroshima (he said Hiroshima was 89 terabecquerels of cesium-137)

Cesium-137 in Common Spent Fuel Pool?

According to the report linked in post 1 (, the common spent fuel pool had 6,291 assemblies in March of 2010. Accordingly, it must have approximately 4.7 X as much Cesium-137 as spent fuel pool #4. 

Put otherwise, the common spent fuel pool  must have over 23,000X as much cesium-137 as contained in the Hiroshima bomb. It must have 23,000X 89 terabecquerels worth of cesium-137.(?)

[Caution: these figures are really only general estimates and do not address the relative depletion of radiation in the spent fuel pools since they're based on Prof. Koide's estimation of the amount of radiation in fuel pool 4, which contained new fuel. So, the figures are useful, albeit only ballpark in nature.]


Now let us look at Spent Fuel Pool #3. 

According to the report linked in post 1, each spent fuel pool at the reactor buildings contained 3,450 fuel assemblies. Hence, we can extrapolate that spent fuel pool #3 had 2.592X as much cesium as spent fuel pool 4 (1331 assemblies).

So, spent fuel pool #3 could possibly have had 12,960X as much cesium-137 as the Hiroshima bomb, or 1,153,440 terabecquerels of cesium-137. (?)

[Caution again--ballpark figures]

Ballpark numbers for cesium-137 are huge for spent fuel pool 3 (and that doesn't include the fuel in the reactor core).

There is evidence unit 3 spent fuel pool was damaged or possibly even destroyed:

First, Visual pictures of the plant suggest spent fuel pool 3 is no longer existent.

Second, Unit 3 had the biggest explosion of units 1-3. We've seen the visual evidence in the video releases of the explosions.

Third, the NRC tapes indicate significant damage to unit 3.

Asahi Flyover: No spent fuel pool seen in Reactor No. 3 — SFP ‘must’ be in center of screen, however we can’t see any of it (VIDEO) ( ;Asahi video availble here:

NRC minutes available here:

Fourth, on March 15 and 16 2011, Tepco and Japanese authorities described unit 3 as their priority: 

Washington Post 3/15: [excerpt]  "At the Fukushima plant, workers were focusing on the unit 3 reactor building, where a white plume of smoke was spotted Wednesday morning, and on unit 4, where fires flared up Tuesday and again on Wednesday morning... Wednesday afternoon, the Japanese military dispatched two helicopters to the Daiichi plant from Kasuminome Air Base in Sendai. A lead chopper was sent to determine whether radiation levels were low enough to continue with the operation. The second helicopter, a Boeing CH-47, followed behind, a huge bucket of sea water dangling beneath it. The CH-47 was slated to make several passes to drop water onto unit 3. But the crew on the first copter found radiation levels were too high to carry out the risky mission." [end excerpt]

"The plant operator described No. 3 -- the only reactor at that uses plutonium in its fuel mix -- as the "'priority.'"


The evidence suggests unit 3 was severely damaged. However, we do not know with any certainty how damaged the pool was, nor the reactor core.

I plan on searching for more information about spent fuel pool 3 in my archives. 

Finding any reports of the common spent fuel pools will be challenging. 

However, the information we have about what was actually stored at the plant (!!!!) and the sheer volume of radionuclides in the fuel rods together make one wonder why unit 3 was dropped from the news when it was the priority in March 2011?

Also, why all the recent attention now to unit 4 and nothing on the other units despite the massive steam/smoke releases over the last few months, documented in the Tepco and JNN webcams trained on the plant?


Robert Alvarez wrote to author of website Akio Matsumura:
–Based on U.S. Energy Department data, assuming a total of 11,138 spent fuel assemblies are being stored at the Dai-Ichi site, nearly all, which is in pools. They contain roughly 336 million curies (~1.2 E+19 Bq) of long-lived radioactivity.
About 134 million curies is Cesium-137 — roughly 85 times the amount of Cs-137 released at the Chernobyl accident as estimated by the U.S. National Council on Radiation Protection (NCRP).
       The total spent reactor fuel inventory at the Fukushima-Daichi site contains nearly half of the total amount of Cs-137 estimated by the NCRP to have been released by all atmospheric nuclear weapons testing, Chernobyl, and world-wide reprocessing plants (~270 million curies or ~9.9 E+18 Becquerel). (cited at Akio Matsumura

NukeProfessional provides the following 2 analyses of uranium and plutonium emitted from the plant

Jim Stone calculates the radiation from the uranium and plutonium in unit 3. I am not familiar with him as a source, but the numbers seem reliable when considered in relation to the cesium-137 numbers

1 comment:

  1. There is an error in the last paragraph.

    "Jim Stone suggests that the uranium and plutonium together."