Wednesday, February 1, 2017

Convenient Acccounts of Fukushima Radiation Exposure Ignore Glaring Issue

Every time I read something about the Fukushima disaster my blood pressure rises.

For example, recent efforts to represent (hypothesized) remnants of melted fuel rods in unit 2 as evidence of containment is revealed as misleading when one considers the size of the reactor (larger than a bus) and the amount of fuel contained within unit 2's:
Justin McCurry January 30, 2017, Possible nuclear fuel find raises hopes of Fukushima plant breakthrough. The Guardian,

Operator says it has seen what may be fuel debris beneath badly damaged No 2 reactor, destroyed six years ago in triple meltdown

Hopes have been raised for a breakthrough in the decommissioning of the wrecked Fukushima Daiichi nuclear plant after its operator said it may have discovered melted fuel beneath a reactor, almost six years after the plant suffered a triple meltdown.

Tokyo Electric Power (Tepco) said on Monday that a remote camera appeared to have found the debris beneath the badly damaged No 2 reactor, where radiation levels remain dangerously high. Locating the fuel is the first step towards removing it. The operator said more analysis would be needed before it could confirm that the images were of melted uranium fuel rods, but confirmed that the lumps were not there before Fukushima Daiichi was hit by a powerful earthquake and tsunami on 11 March 2011. 

The amount of fuel contained of fuel in those reactors was substantial. If TEPCO had found all, or most, of the melted reactor fuel they would know it.

According to a November 16 report by Tepco titled, ‘Integrity Inspection of Dry Storage Casks and Spent Fuel at Fukushima Daiichi Nuclear Power Station,’[i] as of March 2010 the Daini site held 1,060 tons of spent uranium fuel. The total spent uranium fuel inventory at Daiichi in March 2010 was reported as 1,760 tons. The 2010 report asserts that approximately 700 spent fuel assemblies are generated every year.[ii] The report specifies that Daiichi’s 3,450 assemblies are stored in each of the six reactor’s spent fuel pools. The common spent fuel pool contains 6291 assemblies. The amount of MOX fuel stored at the plant has not been reported.

I suspect that TEPCO knows that most of the fuel is gone from unit 2's reactor containment and that what remains is a fraction of the total load, which was either dispersed in the explosions or has left the building.

But what bothers me even more than obfuscation around missing fuel are misleading accounts of radiation exposure.
Case in point:  The article published in CNBC below last week alleges that Fukushima radiation exposure was "far lower" than previously found:
Robert Ferris. Jan 24, 2017. Fukushima radiation levels far lower than previously thought, study finds. CNBC.Com,
Radiation levels remaining from the 2011 disaster at Japan's Fukushima Daiichi nuclear plant appear to be a small fraction of what previous measurements suggested, according to a recently published study that followed levels in tens of thousands of people living near the site of the accident.

Science magazine highlighted the research Monday, calling it the first study to measure individual radiation levels in locals following a major nuclear disaster. The study was published in the peer reviewed Journal of Radiological Protection in December.
I've seen this type of headline before so I was immediately suspicious. I pulled up the journal article and found a glaring issue that problematizes the validity of this conclusion that radiation levels were lower than previously calculated.

Here is the glaring issue ignored in the CNBC's optimistic headline: The radiation monitoring badges were provided to residents in August of 2011. The disaster and radiation exposure began March 11, 2011.

Consequently, RESIDENTS WERE NOT GIVEN BADGES TO MEASURE EXPOSURE UNTIL FULLY 5 MONTHS AFTER exposure, a fact that is acknowledged in the title of the research article but ignored in the news coverage:
Makoto Miyazaki and Ryugo Hayano. 2017. Individual external dose monitoring of alltizens of Date City by passive dosimeter 5 to 51 months after the FukushimaNPP accident (series): 1. Comparison of individual dose with ambient dose rate monitored by aircraft surveys. J. Radiol. Prot. 37 1(
For the measurement of individual external doses, Date City distributed individual dosim-eters (radio-photoluminescence (RPL) glass dosimeters: Glass Badge) to kindergarten-, elementary- and junior high school-children in August 2011. The target group was subsequently enlarged as the production capacity of the supplier increased, and the measurements are still ongoing

How is it possible to conclude that exposure was lower than previously thought when the evidence for that claim is generated from a study that excludes the first 5 months of exposure?

Truth has an especially slippery feel when it comes to Fukushima....



[i] It is worth noting that although this report was produced on 10/26/2010, the file properties indicate the document was modified on 3/13/2011: Integrity Inspection of Dry Storage Casks and Spent Fuels at Fukushima Daiichi Nuclear Power Station (16 November 2010),

[ii] Integrity Inspection of Dry Storage Cask.

1 comment:

  1. Good article! I know just what you mean about that blood pressure thing.