The contaminated water problems at Fukushima Daiichi have been plaguing the plant since day one. In recent months the problems have once again shown themselves to be too much for TEPCO to deal with while the plant continues to contaminate the environment. TEPCO stated that they were again, out of space only to find space after it became apparent the government would not allow them to dump contaminated water into the Pacific Ocean. This is something TEPCO has asked to do repeatedly since 2011 when they dumped contaminated water into the Pacific on top of what has been leaking.
Contamination and contaminated water from the failed reactors is still making its way out of the plant a number of ways, all with long term major implications for the environment and public safety.
The storage ponds were originally intended to be a holding spot for post ALPS treated water. This still contaminated water would have had high levels of tritium but in theory no other contamination after treatment. TEPCO had repeatedly tried to convince the public and the government that they should be allowed to dump the ALPS water into the Pacific. That issue was still being debated when it was discovered the storage ponds were leaking. The storage ponds did not hold ALPS water, instead someone at TEPCO made a decision to put highly contaminated water into the storage ponds. The ponds were not built to the standards needed for holding dangerous liquids due to TEPCO’s own design decisions. So of course the ponds leaked either through seams that failed, the leakage probe system or another route of failure. TEPCO’s sub standard design and the decision to put highly contaminated water into the ponds created a new problem that is making the environmental disaster worse. The high rads water being dumped into pond #2 was from the reverse osmosis system and should have been treated as high level waste, not put into a sub standard pond.
The pond design that failed was approved by NISA, the predecessor agency to the NRA. The decision to put the reverse osmosis contaminated sludge water into the ponds happened more recently. It is not clear if they informed the NRA before doing this or did it without telling them. The contaminated sludge water from the RO system when tested back in 2012 contained plutonium and curium. TEPCO has not released any data on these types of substances in the leaking ponds but there is the high potential that besides the tritium leaking from the ponds, plutonium and curium could also be leaking from the pond that was used to hold the reverse osmosis sludge water. This leaking is happening inland up on the hill, the pond leakage will mix into the ground water and could migrate anywhere the ground water can migrate and also contaminate the soil expanding the disaster zone around the plant.
A recent NHK documentary showed a series of dry bed underground rivers that flow into the plant grounds, two of them appear to go on either side of the units 1-4 reactors. These underground river bed structures could be routes for contaminated water to leave the plant grounds and end up in the Pacific. These may be harder to block off since they are natural underground structures. These could be one of the “mystery” routes for the continued contamination of the areas and sea life near the plant. They could also cause a situation where they draw contaminated water out of the soil around the reactors as a path of least resistance.
The plant grounds have some sort of storm sewer system. Gutters and similar structures to remove rainwater are needed around roads and other areas to prevent rainwater retention and erosion. There are some rather large ditches on site, TEPCO has referred to these at times but have not clarified if the storm drains drain into these or another system. Any storm drains and pipes on site could create yet another route for contaminated water to move. These pipes could also have broken during the earthquake creating a route that could draw contaminated water out of the nearby soil into the pipes. Some types of plants that deal with hazardous substances require runoff rainwater to be collected and monitored in some manner, others simply run it into a nearby body of water or city storm sewer system. It is not clear how the system at Daiichi is constructed but the existence of the system creates another route for moving contaminated water around the plant.
One of the considerable problems in dealing with the disaster is the 400 tons of groundwater that flows into the reactor buildings every day. As the groundwater reaches the area around the reactor buildings it becomes contaminated, adding to the contaminated water problem. TEPCO’s plan was to put some wells in on the inland side of the plant and to pump this groundwater directly out to sea. They assumed groundwater further back up the hill would be clean, allowing them to bypass the mess at the plant. The wells have shown that tritium is already mixed with the groundwater uphill from the plant. While the levels of tritium are fairly small they still show that there is a problem and the plant is leaking back inland, not just out to sea as TEPCO has stressed repeatedly. Small levels of cesium were also found in the wells at various measuring dates. It is not clear if this is back flow from the reactor buildings or radiation spewed across the plant that has sunk into the soil and is pulled into the wells by groundwater. TEPCO wants to dump this contaminated water into the sea. So far they have not been given approval and the idea is meeting resistance from local groups and environmental groups.
Contaminated Water Backflow
There have been some subdued admissions that the groundwater is being contaminated and will migrate inland outside of the plant. The NRA has also admitted that strontium 90 found at the plant will pollute coastal groundwater within 10 years. TEPCO apparently knew this as early as 2011. They had planned a large wall inland of the reactors to block groundwater and prevent contaminated water from migrating. TEPCO ditched the plan due to concerns that the soil was heavily contaminated by the water flowing out of the reactors. There is now some new discussion about creating underground walls around the reactors. A TEPCO-government panel talked with contractors who suggested building an underground wall around the reactors with a clay-like material. The leaking ponds contribute to this as does the damaged reactor units.
Rainwater contributes to the problem. A recent study showed that Typhoon Roke that hit the Fukushima region in 2011 created a considerable spike in cesium being transported into the river systems and into the coastal waters. This same behavior will happen at the plant where contamination deposited on surfaces and the soil will move with the rainwater. At Fukushima Daiichi this rainwater can move high levels of contamination out to sea or wherever the excess rainwater ends up. Excess rainwater that makes its way into the reactor buildings adds to the contaminated water burden at the plant.
The ALPS system is the third in a series of contaminated water treatment systems used at the plant. This larger more complex system is supposed to remove all radioactive contamination except for tritium and is in the testing phase right now. ALPS is expected to be able to treat 250 tons of water per day and up to 500 tons of water per day at full capacity. The plant is currently producing 400 tons per day of contaminated water as leaking reactor water and groundwater mix in the reactor buildings. ALPS will only get ahead of the contaminated water problem if it ran at full capacity most of the time. Any outage or failures would cause TEPCO to lose ground in processing the contaminated water at the plant. The final product from ALPS still contains high levels of tritium. Without some form of tritium removal system, the contaminated water will likely end up dumped into the Pacific Ocean. Tritium is a beta emitter with a 12.32 year half life.
Future Decommissioning Work
The plan to decommission the reactors at Fukushima Daiichi still involves flooding the reactor containment structures with water to shield against radiation as work proceeds. TEPCO has tried to “flood” the reactors already as a cooling tactic. They briefly tried this at unit 1 and discovered it will not hold water. There were also concerns about the stability of the containment structures if they were filled with water. They could become unstable in an earthquake and it was unclear how filling them with water would impact the structural integrity. If they do eventually do this removal tactic it will involve patching as much of the building or containment as possible to make them hold water. This process will likely be imperfect and will create more leaking contaminated water in the process.
The contaminated water problem has been a huge issue since the start of the disaster. Attempts to deal with the problem have mostly been left to TEPCO to figure out. This has proven to have been a poor choice as TEPCO has done the bare minimum or cut corners making projects ineffective or only to have them fail and the money be wasted. A critical window of time where actions could have been taken to mitigate some of the contaminated water outflow may have already passed. Determining if it is still possible to block the contaminated water from leaving the plant grounds requires a larger effort that TEPCO is dedicating to the issue.
The contaminated water issue needs to be solved and will likely require more design, research and money that TEPCO is capable of dealing with. Continuing to ignore the problem is creating more environmental damage in the region both on land and at sea. Much of this damage continues to migrate into the sea where it is not geographically limited to the area. This failure to deal with the contaminated water issues drastically increases the total cost for clean up and hinders any possible recovery for the region.
NY Times Weighs In
As we were completing work on this in depth article, the NY Times released a piece on the water issue at Daiichi. They looked more into the political failures that allowed it to happen. Their commentary on the issue is that TEPCO is quite overwhelmed and more reacting to problems than planning ways to control the situation. The head of the NRA doesn’t think another accident at the plant can be prevented, other experts think TEPCO is not dealing with the disaster in a competent manner.
The NY Times article also points out that the recovery committee is stacked with nuclear industry insiders, many the very people who were running things when the disaster happened. At a time when diverse expertise is critically needed the disaster response itself has become a closed off system, no wonder the response is failing.
“According to some who helped the government plan the cleanup, outside experts might have predicted the water problem, but Tepco and the government swatted away entreaties to bring in such experts or companies with more cleanup expertise, preferring to keep control of the plant within the collusive nuclear industry.”
Highlighting the massive failure of TEPCO and the government-industry committee that is supposed to be overseeing the response is that nobody bothered to get or anticipate the need to gain government approval to dump contaminated water into the sea. Possibly they just hoped when there was no other option the government would be obligated to allow it or possibly it was just more inept planning.
The common thread with all the people they interviewed was that the current entity is in way over their heads and are not capable of dealing with the disaster, the challenges are daunting. There also seems to be an undercurrent of giving up among the experts, that the disaster may be too big of a challenge even for them.
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