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Fukushima Open Thread: "Creeping Disaster"

Unlike most incidents which threaten lives or public safety the Fukushima Daiichi crisis is unfolding slowly but seems headed towards an unpleasant range of potential outcomes:


“We are experiencing an ongoing, massive release of radioactivity,” says Wolfram K├Ânig, head of Germany’s Federal Office for Radiation Protection. “And everyone should know by now that this isn’t over by a long shot.” Nuclear expert Helmut Hirsch says: “All I hear is that people are wondering whether this will turn into a meltdown. But the thing is, it already is a partial meltdown.” The difference, in this case, is that Fukushima is a creeping disaster.

How Dangerous Is Japan’s Creeping Nuclear Disaster? Der Spiegel 28 Mar 11

Work on restoring the stricken site, despite heroic efforts, has been virtually halted by unexpected obstacles and prohibitive radiation levels in and around the plant, especially near Unit No 2:


Tokyo Electric Power Company announced on Monday that a puddle of water was found in a [service] trench outside the No. 2 reactor turbine building at the Fukushima Daiichi nuclear plant on Sunday afternoon. It said the radiation reading on the puddle’s surface indicated more than 1,000 millisieverts per hour.

Radioactive water in external tunnels NHK 29 Mar 11

TEPCO has no specific explanation for these levels; at 1000 mSv/hr a fifteen-minute exposure would consume even the higher radiation limits set for workers during this incident.

Meanwhile efforts to replace salt water with fresh water for cooling continue:



The disclosure about the escaping contaminated water came as workers pressed their efforts to remove highly radioactive water from inside buildings at the plant. The high levels of radioactivity have made it harder for them to get inside the reactor buildings and control rooms to get equipment working again, slowing the effort to cool the reactors and spent fuel pools.

Workers pumped less water into the reactors Monday in an attempt to minimize the overflow of radioactive water from them, slowing the cooling process, Tokyo Electric said.

Hiroko Tabuchi and Ken Belson – Contaminated Water Escaping Nuclear Plant, Japanese Regulator Warns NYT 28 Mar 11

Another disturbing development this morning is the discovery of plutonium in soil samples taken around the plant in recent days:


The government’s Nuclear and Industrial Safety Agency said it remains unknown which reactor plutonium came from and that TEPCO and the science ministry will strengthen monitoring on the environment both in the plant and outside of a 20-kilometer exclusion zone set by the government.

Hidehiko Nishiyama, a spokesman for the nuclear regulatory body, said the detection of plutonium suggests ”certain damage to fuel rods” and said it is ”deplorable” that the toxic radioactive material was found despite various containment functions at the reactors.

Plutonium detected in soil at Fukushima nuke plant Kyodo 29 Mar 11

While true, it is sobering to note that highly toxic plutonium is also regularly found in soil samples as a consequence of atmospheric nuclear weapons testing in the 20th century and the levels found are consistent with what we have now come to accept as “normal.”  The condition of the reactors and spent fuel pools, however, while largely unknown, does not seem to be getting any worse:


[Haruki Madarame, chairman of the Nuclear Safety Commission of Japan] said he cannot predict when the ongoing nuclear emergency will end and pointed to the possibility that fuel rods in the No. 2 reactor, which were temporarily exposed to the atmosphere, have been significantly damaged.

”We must control the water well so it won’t ever go outside” the complex, said Sakae Muto, vice president of TEPCO, at a news conference.

TEPCO revealed the elevated radiation levels in trench water a day after it first detected them, but Muto denied any intention of withholding information from the public.

On Monday, TEPCO continued to remove highly radioactive water from inside reactor buildings at the crisis-hit plant, in an effort to enable engineers to restore the power station’s crippled cooling functions. The turbine buildings are equipped with electric equipment necessary to cool down the reactors.

Plutonium detected in soil at Fukushima nuke plant Kyodo 29 Mar 11

The problem is that the radioactivity is spreading beyond the containment and the close proximity of Unit No 2 to the other crippled plants is a threat as levels rise.  It would seem the gallant efforts of the workers and engineers on site are not unlike trying to fill a bucket with a hole in it with the added complication that the leaking water poses a significant radiation hazard and time, in this case, may be working against them.  For the sake of the hundreds of thousands who lived in the near vicinity of the plant and those still downwind of this tragedy our hopes are with them.  But it looks like redoubled efforts will be required and we will only slowly discern the scope of this tragedy.


62 comments

  1. HappyinVT

    workers will be forced to evacuate?  My understanding is that they’ve brought in more workers in order to rotate them out in shorter shifts.

  2. Shaun Appleby

    Keep pumping without flooding the site in radioactive waste water:


    While parts of the Japanese plant have been reconnected to the power grid, the contaminated water – which has now been found in numerous places around the complex, including the basements of several buildings – must be pumped out before electricity can be restored to the cooling system.

    That has left officials struggling with two sometimes-contradictory efforts: pumping in water to keep the fuel rods cool and pumping out – and then safely storing – contaminated water.

    Hidehiko Nishiyama, a spokesman for Japan’s Nuclear and Industrial Safety Agency, called that balance “very delicate work.”

    He also said workers were still looking for safe ways to store the radioactive water. “We are exploring all means,” he said.

    More radioactive water spills at Japan nuke plant AP 28 Mar 11

    Not sure there is an immediate solution to this without mooring a tanker offshore for later waste disposal and scrapping.

  3. fogiv

    increasing ocean contamination.  i can hardly stand to think about this stuff.  scary, but shouldn’t someone be talking about this aspect?  is my concern unwarranted?

  4. Shaun Appleby

    From someone who should know, the head of safety research for boiling-water reactors at General Electric when the company installed the units at Fukushima discussing Unit No 2:


    At least part of the molten core, which includes melted fuel rods and zirconium alloy cladding, seemed to have sunk through the steel “lower head” of the pressure vessel around reactor two, [Richard Lahey] said.

    “The indications we have, from the reactor to radiation readings and the materials they are seeing, suggest that the core has melted through the bottom of the pressure vessel in unit two, and at least some of it is down on the floor of the drywell,” Lahey said. “I hope I am wrong, but that is certainly what the evidence is pointing towards.”

    The major concern when molten fuel breaches a containment vessel is that it reacts with the concrete floor of the drywell underneath, releasing radioactive gases into the surrounding area. At Fukushima, the drywell has been flooded with seawater, which will cool any molten fuel that escapes from the reactor and reduce the amount of radioactive gas released.

    Lahey said: “It won’t come out as one big glob; it’ll come out like lava, and that is good because it’s easier to cool.”

    Ian Sample – Japan may have lost race to save nuclear reactor Guardian 29 Mar 11

    If true this is not good news as the containment of No 2 is assumed to be breached to some degree.

  5. Shaun Appleby

    With profound implications for workers and the recovery attempt:


    …two days after the Kyodo agency report, on March 25, TEPCO made public measurements of different isotopes contributing to the extremely high measured radioactivity in the seawater used to cool reactor No 1. Again, a piece of the data jumped out at [Dr. Ferenc Dalnoki-Veress, a Research Scientist at the Monterey Institute of International Studies]: the high prevalence of the chlorine-38 (CL-38) isotope. CL-38 has a half-life of 37 minutes, so would decay so rapidly as to be of little long-term safety concern. But it’s very presence troubled Dalnoki-Veress. Chlorine-37 (CL-37) is part of natural chlorine that is present in seawater in the form of ordinary table salt. In order to form CL-38, however, neutrons must interact with CL-37. Dalnoki-Verress did some calculations and came to the conclusion that  the only possible way this neutron interaction could have occurred was the presence of transient criticalities in pockets of melted fuel in the reactor core.

    Eben Harrel – Has Fukushima’s Reactor No. 1 Gone Critical? Time 30 Mar 11

    Since then, Dr Edwin Lyman, a physicist with the Union of Concerned Scientists, and a trustworthy commenter, has questioned not Dr Dalnoki-Veress’ finding but the TEPCO data it was based on, “I think, given the error they committed in Unit 2 (first reporting a huge concentration of I-134, which wasn’t actually there), I’d be wary of attributing too much significance to a single anomalous measurement.”

    Either way it is not good news, a recriticality, even transient, could be a death sentence for nearby workers, on the other hand it seems the data from TEPCO is now considered highly unreliable by experts.  Take your pick.

  6. Shaun Appleby

    April’s off to an uneven start:


    Radiation levels increased sharply inside and outside the Fukushima Daiichi nuclear power plant Thursday, slowing work on the devastated facility again and once more throwing into doubt the integrity of the containment vessels that hold the fuel rods.

    Tokyo Electric Power Co. officials said the level of radioactive iodine in water at the plant hit levels 10,000 times the permissible limit, preventing workers from getting near the water, which accumulated during early efforts to prevent a full-fledged meltdown by flooding the plant.

    […]

    Engineers speculated that the radiation surges may be coming from a partial meltdown of the fuel core of reactor No. 1. It appears that small segments of the melted fuel rods in that reactor are undergoing what is known as “localized criticality,” emitting brief flashes of heat and radiation.

    Julie Makinen and Thomas H Maugh II – Radioactivity surges again at Japan nuclear plant LAT 1 Apr 11

    “Localized” criticality sends neutrons through every known bit of shielding basically like a knife through butter.  It is unpredictable and potentially fatal with instantaneous doses:


    Since 1945 (and not including Chernobyl or the Japanese reactor accidents of 2011) there have been at least 21 deaths from criticality accidents; seven in the United States, ten in the Soviet Union, two in Japan, one in Argentina, and one in Yugoslavia. Nine have been due to process accidents, with the remaining from research reactor accidents.

    Criticality Accident: Incidents Wikipedia

    Not good.

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