The saga of the Fukushima Daiichi Nuclear Power Plant disaster continued this month, when Tokyo Electric Power Co (Tepco) sent two specialized, remote – controlled robots separately into the No 1 reactor to survey damage and record radiation levels, but both had to be abandoned inside due to malfunctioning equipment.
Claire Bernish(The Pontiac Tribune) – The saga of the Fukushima Daiichi Nuclear Power Plant disaster continued this month, when Tokyo Electric Power Co (Tepco) sent two specialized, remote – controlled robots separately into the No 1 reactor to survey damage and record radiation levels, but both had to be abandoned inside due to malfunctioning equipment. Hitachi – GE and the International Research Institute for Nuclear Decommissioning (IRID), designed the snake – like, form – shifting robot, to maneuver in unknown terrain, and to tolerate the extremely high radiation levels present inside the reactor for up to ten hours — a prospect which would be impossible with standard electronic devices.
The first robot completed two – thirds of its planned route on April 10, charting the location of debris while measuring radiation levels, in preparation for the next stage of decommissioning. The pictures it relayed are the first glimpses into the reactor, one of three that suffered complete meltdown after an earthquake and subsequent tsunami in March 2011 triggered the nuclear disaster — now widely considered to be on the same scale as Chernobyl.
The following video from the first robot, revealed the eerie aftermath of the disaster:
The robot was found to tolerate the radiation well, and with levels from 7.0 to 9.7 sieverts/hour, being lower than expected, future missions may be able to remain inside for a longer duration and could possibly include wireless devices.
The second venture inside employed an identical tube – shaped robot, which completed most of its mission, recorded somewhat lower radiation levels than the first. Footage includes steam rising from the lower part of the reactor, and first glances of the water which fills the unit. The robot’s light hitting rusted steel grating appears to glow green in the distortion, and the circle appearing in the water is just a reflection.
Eventually, the second robot’s camera succumbed to radiation and stopped functioning, but was able to locate the first, verifying its tread became immobilized on the steel grated flooring.
In combination, the videos show that debris which litters the area will not impede the next goal of sending a robot into the highly contaminated basement area of the reactor, though this likely won’t happen until next March. The decision was made to forgo further attempts to forcibly retrieve either device due to growing concerns they could become stuck elsewhere, possibly blocking access for future missions.
Tepco has come under heavy criticism for its handling of the disaster (rated 7 of 7 possible, or “major accident” by the International Atomic Energy Agency) and the subsequent feeble attempt contain the aftermath. In 2012, a scathing report which was commissioned by the Japanese parliament, found that though the magnitude 9.0 earthquake and consequent tsunami were “shocking”, the disaster at Fukushima Daiichi was “a profoundly manmade disaster — that could and should have been foreseen and prevented”, and for all intents and purposes, was “made in Japan”. After the massive quake knocked the plant’s main source of electricity offline, a mismatched socket prevented an effective secondary source from taking over. The enormous influx of water from the tsunami rendered backup diesel generators useless, and physical damage to both plant structures and the surrounding area prevented outside aid from reaching the plant.
Intra – facility communications were disabled with the loss of power, so lack of proper emergency training and knowledge, as well as improperly inspected equipment, compounded the problem exponentially, leading one critic in the field to describe the response as “the keystone cops”. But Tepco, the government, and regulatory agencies all knew at least five years prior, that this exact scenario — power failure due to a tsunami — was conceivable. In Tepco’s eyes, the consequences of shutting down the plant in order to reinforce structure and implement safety measures outweighed the perceived improbability of such an accident; and the regulators, reluctant to use foreign technological advancements, repeatedly colluded in signing off on the company’s procrastination.
Inadequate methods to contain the innumerable issues concerning water since the initial calamity are turning the clean up and decommissioning process into a major fiasco. To keep the melted fuel constantly covered in water, a makeshift system of hoses and pipes pumps water into the reactor, then treats it in preparation for storage in above ground tanks. Approximately 350 of these tanks used rubber seals only meant to contain the radioactive waste for up to five years. And not all of the water makes it to the tanks, as a sizable portion leaks into basement area and, due to structural damage from the quake, leaches into the soil, ultimately winding up in the ocean.
In July 2013, just 80 ft inland, faulty equipment led to an enormously inaccurate reading from a 50 ft deep observation well located between reactors No 1 and 2, of 900,000 becquerels/liter, which was most likely at least half composed of strontium – 90, a radionuclide not previously measurable at the site. After the equipment was fixed, the adjusted figure turned out to be far closer to 10 million becquerels/liter — more than three times greater than the previous record measurement. A subterranean channel, found to be the source of a highly contaminated leak dumping directly into the ocean immediately following the initial disaster, is located just 20 ft from this well.
One 300 metric ton (80,000 gallons) leak from a tank in August 2013, seeped into the ground after breaching a sandbag – reinforced concrete barrier intended to contain it, with the radiation level measured two feet above the resultant puddle of 100 millisieverts/hour — five times the yearly maximum exposure acceptable for workers. But this revelation came on the heels of an admission by Tepco that 300 tons of contaminated water was leaking directly from the reactors into the sea, per day.
Then in February this year, a drainage ditch emptying directly into a bay and thus straight into the ocean, measured radiation levels 50 to 70 times higher than the already elevated levels on site. Just days later came the news of Tepco’s failure to disclose for ten months, its knowledge of an accumulation of highly radioactive cesium – 137 tainted water on the roof of a building, measuring 23,000 becquerels/liter, which had been draining directly into the sea by way of a gutter, with every rainfall. After being shut down, readings remained 10 to 20 times above average.
Human error led to a 100 ton leak when two valves were mistakenly left open, resulting in a radioactive plume half composed of strontium – 90; and though the volume of the spill was less than other major breaches, the content measured an extraordinarily high 230 million becquerels/liter — 46 times more contaminated than groundwater at the site — and for the sake of perspective, 3.8 million times the legal limit for drinking water.
The most recent leak was discovered in March, when Tepco disclosed that some 750 tons of strontium – 90 laced rainwater, measuring 8,300 becquerels/liter, had overflowed from mounds near the faulty tanks, though the company maintained it had probably just permeated the ground and would not reach the ocean.
So, what does all this mean? If you’ve paid even the slightest attention to the plethora of reports citing conflicting statistics, and in some cases citing the same statistic for conflicting conclusions, you realize the answer is up for debate.
When it comes to the Fukushima disaster, people, including scientists, tend to fall on the scale at one extreme end or the other, making conclusory declarations altogether untenable. Even the facts can be conveniently rearranged to fit with presuppositions about an event of this magnitude, for which the consequences aren’t tangible. What holds greatest weight in truth, actually stands somewhere in the middle, drawing enough fear to be cautious, but enough rationality and deduction to not be overtaken by it.
The preceding figures were not included to foster unnecessary paranoia, but are merely for illustrative purposes. Evidence based on scientific study, has decisively placed the bulk of concern for Fukushima’s radioactive leaks with workers at the scene, closely followed by those living in close proximity to the plant at the time of the quake and tsunami.
Reports of numerous deaths and cancers of the thyroid are not based in fact, and have been disproved. With that said, the leaks composed of strontium – 90 are relatively new, and could pose cause for concern. Strontium – 90 is a beta – emitting radionuclide with a half – life of nearly 30 years, and behaves in the body much like calcium. Once ingested in food or drink, and with a general retention rate of 20 – 30%, strontium – 90 concentrates in bone and bone marrow, where its effects can be cumulative, possibly leading to bone cancer and leukemia.
Any fish, particularly smaller species, in the vicinity of the reactors probably have high concentrations of this radionuclide, but species like bluefin tuna which travel long distances, will experience decline in strontium – 90 concentration, eventually leaving its body altogether. A major concern seen online surrounds cesium, both -134 and -137, and concern for eating tainted fish.
Cesium – 137 can be indicative of nuclear weapons testing, and it’s extremely important to note that due to nuclear weapons testing in the Pacific by the US, France, and Britain in the 1950s and 60s, levels were already detectable. Cesium – 134, on the other hand, cannot be produced by nuclear weapons tests, so it acts as a specified marker for contamination from a nuclear power facility. Both radioisotopes are diluted significantly in the ocean, and an ongoing project including scientists and concerned citizens, actively measures cesium levels at various posts along the coast, from Canada southward to the US and Hawaii, and though levels have become recordable within the last year, are still insignificant.
Perhaps the single area of agreement with the myriad issues surrounding Fukushima, is that stabilization is urgent and imperative. With the jury – rigged system in place presently, cleanup has amounted to little more than stomping out fires. After the brutally critical report, Tepco has taken a bit of a back seat to government and regulatory agencies for the decommissioning process.
As time passes and human and mechanical error severely hinder progress, there are louder calls from the scientific community to simply encase the reactors in cement and steel, as was done with Chernobyl. Reactor No 4, has not attracted much attention since discussion has focused on the reactors which suffered meltdowns; but Tepco confirmed the structure can only withstand a quake into the upper part of the 6 magnitude.