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Water Management and Mismanagement at Fukushima

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This photo shows the reactors (right) and the storage tanks for contaminated water (left) at Fukushima Daiichi on March 3, 2013 (Source: Google Earth)

In December 2011, the government of Japan announced with great fanfare that the nuclear reactors damaged in March at Fukushima Daiichi were in a state of “cold shutdown” and that the release of radioactive materials from the reactor containment vessels had been brought under control.

In August 2013, following months of worsening news, Masayuki Ono—acting nuclear power chief of the Tokyo Electric Power Company (TEPCO) that owns the reactors—sang a different tune, admitting that the utility was unable to control the release of radioactively contaminated water into the environment. These ongoing and uncontrollable discharges led Japan to declare this week that the leakage represented a “serious incident” rating a 3 on the International Nuclear Event Scale (distinct from the original accident at Fukushima, which rated a 7 on this scale).

Ongoing Water Leaks

In fact, the degree to which TEPCO could “control” the massive volume of radioactive water at the Fukushima Daiichi site was always in question. Soon after the accident began in March 2011, it became apparent that much of the cooling water being injected into the damaged reactor cores and spent fuel pools was leaking from the reactor vessels and primary containment vessels via unknown pathways and ending up in the reactor buildings and turbine building basements, as well as in various trenches and tunnels crisscrossing the site, some of which were not isolated from groundwater and tidewater. A number of temporary fixes were applied to prevent the ongoing release of large quantities of radioactive materials into the ocean. In addition, TEPCO installed a water processing system that was able to remove and concentrate one of the most troublesome radioactive isotopes in the cooling water, cesium-137, and built a vast farm of tanks to store water that was not being recycled for cooling. Yet these measures have been unable to prevent contaminated water from leaking from engineered structures into the soil. The leak from a storage tank of 300 tons of partially decontaminated water that TEPCO announced on August 19th of this year was the latest and most severe of a series of such releases.

At the same time that radioactive material is leaking into the soil beneath the site, one thousand metric tons of groundwater is flowing daily into Fukushima Daiichi from the inland mountains. About 400 tons is believed to be accumulating each day in the reactor buildings and turbine buildings, and the remainder is being discharged to the harbor. This provides a mechanism for the constant flushing of radioactive contamination in the soil below the reactors into the sea. TEPCO believes about 300 tons of the groundwater flowing daily into the harbor is becoming contaminated. It has begun to pump and store some of this groundwater but so far can only handle a fraction of the volume.

TEPCO has been evaluating a wide range of measures to attempt to stabilize the site, including construction of a so-called “ice wall” that would create a barrier of permafrost to divert the groundwater flow around the contaminated area. It has also finally requested international help. But the government of Japan, which has lost patience with TEPCO, has announced that it is taking the lead in developing emergency measures, although the extent to which the government will assume responsibility for dealing with the crisis is unclear

What Does It Mean?

Although the uncontrolled daily release of radioactivity into the environment represents a failure on the part of TEPCO to safely manage the Fukushima site, it does not yet pose a major public health threat comparable to the releases of radioactivity that occurred in the weeks following the accident, which were millions of times greater. The inability to safely contain the radioactivity at the site is first and foremost a threat to the workers who must report each day no matter how precarious the conditions. The contamination of more than ten workers in recent weeks, resulting in an expansion of areas where respiratory protection is required, has highlighted the dangers faced by personnel.

However, the situation is a stark reminder of how fragile things still are at Fukushima, which is especially alarming given the enormous quantity of radioactive material that still remains within the reactor cores and spent fuel pools. Things could rapidly get worse if, for example, additional wastewater tanks started to leak. And the potential for another earthquake that might cause soil liquefaction under the site, as reported by the Japan Times this week, raises the possibility of sudden and much larger releases. The international community should not be lured into a false sense of confidence during the periods when little news about Fukushima is being reported. The situation is dire and requires an urgent response.

 

Posted in: Japan nuclear, Nuclear Power Safety Tags: , ,

About the author: Dr. Lyman received his PhD in physics from Cornell University in 1992. He was a postdoctoral research scientist at Princeton University's Center for Energy and Environmental Studies, and then served as Scientific Director and President of the Nuclear Control Institute. He joined UCS in 2003. He is an active member of the Institute of Nuclear Materials Management and has served on expert panels of the Nuclear Regulatory Commission. His research focuses on security issues associated with the management of nuclear materials and the operation of nuclear power plants, particularly with respect to reprocessing and civil plutonium. Areas of expertise: Nuclear terrorism, proliferation risks of nuclear power, nuclear weapons policy

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12 Responses

  1. Richard Solomon says:

    Thanks for a succinct summary of the circumstances going on at Fukushima. Things certainly appear potentially catastrophic.

    Per other reports, the Japanese government is (finally) recognizing that TEPCO cannot cope with these events which are cascading into a downward and very troubling cycle. I have heard nor read of what specific steps the government intends to take to try to contain the situation, however.

    Is there anything UCS members can do to try to help nudge/support the Japanese government into taking constructive, proactive steps about this?

    Anything we can do to point out the dangers of spent nuclear fuel sitting in pools of water here in the USA to the NRC, our elected representatives, etc?

  2. Bernie Goetz says:

    If filtering of the water on the site is impractical perhaps all the unfiltered radioactive water stored on the site should be directly piped or barged far enough offshore so currents would disperse it away from land. This might be unpopular but should not cause significant human health effects. A long time ago radioactive waste was just dumped in the ocean, nothing to be proud of. I think the stored radioactive water really needs to get off the site as it greatly distracts from and hinders cleanup of the reactors and fuel pools. It looks like both Tepco and the Japanese government are playing politics. In this kind of environment responsible engineering decisions are more difficult.

    BTW, all this could have been avoided if what I’ve advocated for 30 years was in place. For both pressurized water reactors and boiling water reactors there should be a backup emergency procedure to depressurize the reactor as quickly as possible (avoiding stress cracking) while keeping the core covered with water and allowing unpressurized boiling by venting from the top of the reactor vessel. Its easy and cheap to have a reliable unpressurized water source. This could prevent future meltdowns. Three Mile Island taught me and some others (that were ignored) that the only thing that is really important is core integrity.

  3. Bernie Goetz says:

    Also, I assume there are plans to build new prefab reactor disassembly buildings over the existing damaged reactor buildings, or to use the columns and beams of the damaged reactor buildings for this purpose. These structures would have rails for cranes and cameras. Probably all damaged fuel should trucked or barged away to a different clean site.

  4. Bernie Goetz says:

    They plan to spend $470M to build an “ice wall”. If this seawall actually stops the water, the ground water level on the site will either eventually rise and flood the site (a fiasco!), or the water will go to adjacent property and thence to the sea, or the water might go under the seawall. I think the radioactive site water should be preferably filtered and then dumped into the deep ocean far offshore. If it can’t be filtered so be it, ocean damage would be insignificant . There is no other answer unless the water is pumped or barged off the site. Radioactive water should not be stored on the site; it hinders cleanup and causes other problems. To avoid offending the fishing industry and public cleanup on the site is severely hindered.

  5. Bernie Goetz says:

    Suggested cheap test: (1) Pick a sensible location far from land where a discharge pipe from the site could dump site water into the deep ocean. (2) Barge about a tank full (300,000 gallons) of highly radioactive water to this location and discharge it in the same way a pipe from land would, at a time when currents would carry the discharge into the deep ocean. (3) Have radiation levels at a number of places in the ocean monitored by the Japanese government, Tepco, a fisherman’s group, and outside groups to determine if there is a health risk to the Japanese or world public.

  6. Fritz Hass says:

    For me, they´re just waiting for the next earthquake or Typhoon flushing all of the contaminted water into the pacific ocean.

  7. Bernie Goetz says:

    Fritz makes a good point – storing water on the site has big risks. Sensible ocean dumping far from shore in the deep ocean would likely protect the Fukushima beaches and Japanese coastal waters much more than storing that water on the site. Fishing at the dumping vicinity should be banned as bottom feeding fish there could injest some detectable radioactivity; these fish could be easily tested. The Pacific ocean holds 10 power 21 kilograms of water. Suppose 100,000 kilograms of reactor fuel were directly flushed in the Pacific (unlikely) over the course of a year. The concentration of dissolved radioactive material would still be very small. India and China might dump 100,000,000 kilograms of conventional waste in the Pacific each day. I think the Japanese are ignoring the big picture and nit picking about the fish. Other countries should not complain as the biggest Pacific impact, although probably negligible, would be in waters near Japan.

  8. Fritz Hass says:

    Hm. I just re-thought what i said yesterday. Let´s say, an earthquake strikes and damages a number, if not all, watertanks. But also further damages the already wrecked buildings with ther SFPs, causing bigger leaks to them and causing them to run dry.
    Who then can help? You cannot send in people due to the then enormous radiation levels everywhere, will they just let the fuel ignite?
    It seems, placing the watertanks near and above the wrecked plant(s) may not be very smart.

  9. Bernie Goetz says:

    Hopefully the new filtration system will work well. But if it doesn’t they should accept lesser filtration. Keeping water on the site is impractical in the long run.

  10. Bernie Goetz says:

    Sorry for the frequent posts. Did they try course back-flush filters prior to finer filtering? Trucking away the radioactive sediment should be no big deal.

  11. Bernie Goetz says:

    I’d like to withdraw my suggestions and probably won’t comment any more on this. Japan has been hell on the fish. They should do what the fisherman want. No ocean dumping!

  12. Jane Jackson says:

    Why didn’t TEPCO bury Fukushima’s reactors in leaded sand, as was done at Chernobyl?

    I ask because a physicist colleague wrote recently:

    2.5 years – or 1000 days – after 3 of 6 of Fukushima’s nuclear reactors melted, 3 radioactive cores are cooled daily by 300 tons of water. Popping like 1000 giant highly radioactive mushrooms, 1000 tanks filled with 300 tons of radioactive water crowd the plant, with one added each day. At least 3 tanks leak, one leaches 1.8 Sv/hr – the equivalent of 100,000 chest X-rays per hour, or 1000 CT scans each hour.

    Soviets buried Chernobyl’s reactor in 4500 tons of leaded sand within 4 days by helicopter, added a cooling barrier underneath in 10 days, and a sarcophagus in 5 months in 1986.

    In 2013, we CAN be better than this!

    They should have asked for help from those who had gone through it before. For example, both Russian and later German robots excavators were tried at Chernobyl to clear the nuclear reactor debris. All robots froze because of immediate severe damage to their electronics from excess radiation. Workers cladded with lead had to be sent for 5- to 10-minute shifts to do the job, 2 5 years later.

    TEPCO just repeated the same error, and still sent robots to try to clear 3 reactor building. Of course they failed. Right there, the Japanese government should have intervened. Have them learn and do what worked from the largest pool of real experts, instead of repeating what did not work.

    The 3 reactor cores and fuel are slowly dissolving into the ocean from the many rains water run-off, while at the same time TEPCO has turned into a high volume factory of highly contaminated water that they do not even seem to understand should be decontaminated daily and recycled for cooling. They have to encase the 3 cores and the 5 spent fuel pools in leaded silica (sands melt into silica on the hot cores) before it is too late – ASAP!