With two robot-probe operations apparently encountering increasingly high radiation levels inside the crippled Fukushima Daiichi nuclear plant during the past three weeks, some media reports suggested the radiation count was climbing rapidly. It didn’t help temper that view when plant operator Tokyo Electric Power Company (TEPCO) had to prematurely halt the second operation last Thursday to yank out the robot probe. Radiation had begun to dim the view of the attached cameras, threatening to leave the robot blinded and therefore unable to retrace its steps and escape the rubble. A TEPCO official explained that nuclear engineers conducted radiation lab tests prior to the operations taking place. This enabled the engineers to study the images taken in the first probe and estimate the different radiation levels—the highest of which was estimated to be 530 sieverts an hour. An estimate based on images taken during the second probe put the level as high as 650 sieverts an hour. (To put those numbers in context, when you take an abdominal X-ray, you’re exposed to about 4 millisieverts of radiation.) TEPCO says it is not particularly surprised at these numbers given that its probes were approaching the reactor vessel. “And these are not direct measurements, but are based on the amount of image noise produced,” a company official emphasized. “There is also a plus or minus error-margin of 30 percent.”
IEEE Spectrum 14th Feb 2017 read more »
Dr Helen Caldicott, explains recent robot photos taken of Fukushima’s Daiichi nuclear reactors: radiation levels have not peaked, but have continued to spill toxic waste into the Pacific Ocean — but it’s only now the damage has been photographed.
Independent Australia 13th Feb 2017 read more »