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CONTAMINATED WATER IN FUKUSHIMA

Fukushima No. 1 can’t keep its head above tainted water

by Reiji Yoshida

Staff Writer

More than two years into the triple-meltdown crisis at the Fukushima No. 1 power plant, workers continue to wage a desperate battle to keep the stricken reactors cool while trying to contain the 400 tons of radioactive water produced by the process each day.

Tokyo Electric Power Co. must decommission the three reactors, but the water is thwarting the effort. The decommissioning, if it ever starts, will take decades.

Here are some questions and answers on the encroaching problem and its implications for public health and the environment:

Why is radioactive water accumulating and how much is there?

As of May 7, Tepco had routed 290,000 tons of radioactive water into some 940 huge tanks at the complex, but 94,500 tons remain inside the basement floors of the reactor buildings and other facilities.

Tepco must perpetually pour water over the melted cores of reactors 1, 2, and 3 via makeshift systems to prevent the fuel from melting and burning again.

But the cores’ containment vessels were damaged by the meltdowns, allowing the highly radioactive coolant water to leak and flow into the basements. The dangerous radiation levels have prevented workers from getting close enough to fully assess the damage, let alone start the decommissioning process.

Compounding the problem is some 400 tons of groundwater that is also entering the basements of the tsunami- and explosion-damaged buildings, mixing with the leaking coolant water.

Tepco has been operating a water-recycling system to drain the basements that is supposed to extract cesium before recirculating the water back to the reactors. But the added inflow of the groundwater is exacerbating the threat.

In response, all Tepco has been able to do is build more storage tanks.

What problems will the water eventually pose?

Tepco says there is a limit to how many tanks the complex can accommodate before the site runs out of storage space.

Tepco said it can boost storage capacity from 430,000 tons from this year to 700,000 tons by mid-2015 by clearing a forest and other space in the compound. The move is expected to buy them about three years’ time.

Tepco is proposing some of the water be dumped into the sea after processing it to remove most, but not all, radioactive isotopes. Local fishermen strongly oppose the plan as it will taint the image of their produce.

Previous discharges into the Pacific have effectively contaminated the sea. Failure to store it means it will probably flood the whole compound and end up in the ocean anyway.

Neither Tepco nor government experts have come up with any other viable solutions.

Will the processed water pose health or environmental risks?

According to Tepco, the processed water could theoretically be safe, but fishermen and consumers disagree.

Tepco has been using an advanced liquid processing system made by Toshiba Corp. to decontaminate the coolant water.

ALPS can bring the density of 62 main radioactive substances below detectable levels, including strontium and plutonium.

Tritium is the exception, however. Tepco says the tritium level in the contaminated water is between 1 million and 5 million becquerels per liter. The legal limit is 60,000.

Tepco thus wants to dilute the water to bring the tritium density below the legal limit by dumping it into the sea. It has promised not to dump any without gaining the nod of local fishermen first.

Tritium, a common hazard at nuclear plants, can increase the risk of cancer if ingested and has a half life of 12.3 years. It is about 1,000th as radioactive as cesium-134 and -137.

Are there other concerns over water-related facilities?

Tepco revealed on April 5 that radioactive water stored in makeshift cisterns with coamings and surface covers were leaking into the soil.

This forced the utility to stop using the reservoirs, which were basically lined trenches with lids, and pump some 24,000 tons of tainted water out of them and into aboveground tanks.

The transfer is expected to be finished later this month.

Experts also are worried about the integrity of the 940 aboveground tanks built as of April 1, since 280 of them are considered “temporary” because they can only be used for up to five years. These are made of steel plates bolted together with waterproof packing to seal the seams, unlike welded steel tanks that offer a longer-term solution.

Tepco will need to start repairing or replacing the temporary tanks in spring 2016.

Tepco has dug 12 wells to intercept groundwater before it seeps into the reactor building basements. Will this work?

Yes, but only to a certain extent.

The wells were dug on the mountainside above the damaged buildings. Tepco plans to pump up as much groundwater as possible to keep it from entering the basements as it heads to the sea.

But Tepco estimates the wells can only pump up 100 of the 400 tons leaking into the buildings every day.

Tepco was going to release the well water into the sea because its radioactivity is much lower than the safety standards for drinking water set by the World Health Organization.

It suspended the plan on May 13 after the local fisheries association vetoed the idea, fearing any further discharge would only worsen the already marred image of local seafood.

The Weekly FYI appears Tuesdays. Readers are encouraged to send ideas, questions and opinions to hodobu@japantimes.co.jp

  • Alt-Idea

    Alternative contaminated water processing idea: Build a large water processing machine onsite: 1. Distill the contaminated water 2. Filter the vapour from the steam 3. Build a single large earthquake proof underground building near the site. 4. Store the contaminated filters in the building. 5. Use existing storage tanks for interim storage before processing.

    • Jim

      Build a large earthquake proof building? Really? I’m sure that’s exactly what they had in mind when they built Fukushima, Mr. Wizard.

      • Alt-Idea

        Today’s materials technology offer us new options for designing safer storage buildings. I envision a large Flexible underground sealed container for storing the contaminated distillation filters. (http://www.livescience.com/5680-flexible-building-survives-powerful-test-earthquake.html). Flexible walls and pallet racks within the container, able to successfully ride earthquake movement without breaking any joins, and protecting the storage. Equally important to storage, is designing a distillation steam filter with properties that can capture 100% contamination. Converting the waste from water to solid, removes the possibility of dumping into the precious ocean. All we need now, is a material’s scientist to design the filter…

  • http://www.facebook.com/iconofcharles Charles Ostdiek

    it’s all so ghastly. I can think of no fitting punishment for the daiichi managers who declined to make the plant safer for fear that the public would feel it to be unsafe. gross and reckless depraved indifference to basic humanity? mass manslaughter? but they were mentally sick, so maybe a diagnosis and treatment? early onset necrophilia? degenerative thanatophilia?

  • Guest

    and yet, they want to restart reactors all over the country.
    These are some seriously misguided people that place money ahead of human life. We can only hope that they are the ones stricken by radiation poisoning, along with the rest of us.

  • Chris Herz

    Nuclear power is so safe — we need more and more of it.

    • Thoughtful_Rationalist
    • http://getironic.blogspot.com/ getironic

      Remind me what the death count is due to the reactor blowing up?

      • thedudeabidez

        Check back in a few years after cancers have had time to gestate. You may also want to look into the number of people who lost their homes and livelihoods due to the reactor(s) blowing up.

  • http://www.jaapdenhaan.blogspot.nl/ JAHAAN

    Nuclear energy has been promoted as clean, the large amount of waste stored in tanks that have proven to leak
    aside. Various means have been studied without optimistic prospect. There are no geological sites that are predictably safe enough by earthquakes. There are aging nuclear reactors in some countries, waste grounds have been found contaminated. Higher levels of radiation are questioned that science may not even have been able to explore. Alternatives are implied that may not be as cheap, but will take away the risk of nuclear fission in the meantime.

  • Keith Thomas

    Clearly they have to stop the inflow of the 400t/day of relatively clean groundwater. There are flow barriers and diversions that can be constructed and cements and sealants can be injected into the flows to help do this (ref BP Gulf of Mexico).

    As they seem to be doing they should be able to remove most of the heavy radioactive contaminants from the water by reverse osmosis to allow its continual reuse so as to limit the need to store ever more water in temporary tanks. The residual tritium may similarly be able to be absorbed onto charged surfaces and then recovered from them as concentrates. All of this can be designed to be done robotically and should avoid the dangerous current linear use and waste storage problem.

    Rather than storing the water in above ground temporary tanks that leak it may be smarter to build a large lagoon that is lined with a good membrane (as in landfills and tailing ponds) and then pump the contaminated water into submerged balloons protected by a second balloon membrane. This allows you to monitor leaks via contamination of the lagoon water but also holds the contaminated water in dual flexible earthquake-proof balloon and lagoon membranes and confined to the protected lagoon rather than in tanks that risk leaking into the soil and the environment.

    However all of this is theory and means nothing if the Japanese have not yet got the message and plan restarting their other reactors. Also what is going on in the elevated pool of spent fuel rods in reactor 4 that risks collapsing? Very worrying and sad.

  • paulelan

    From the start of this nuclear accident it was clear that the effects where beyond control. Radioactive contamination is only cosmeticaly being repaired. Japan as a nation that supposedly owes its existence to the goddess of the sea, is destroying its environment and has a culture of denying catastrophy, obeying and following leaders and believing in a heroic endvictory. With radiation penetrating the environment the Japanese have created their own hell. Time to forget about the shame and face reality.