The nuclear disaster at Fukushima marks its 4th anniversary today. This is a report on the conditions at what's left of the facility at this point in time. What has been tried and/or accomplished - or ignored - there in regards to ongoing radioactive pollution still leaking into the atmosphere and the Pacific Ocean from the facility, and where TEPCO, Japan and the rest of the nuclear world both industrial and governmental plan to go with it from here.
Because this overview covers a number of developments over a period of years, I won't apologize for its length. But due to length, I have chosen developments of particular interest for what they convey about both the overall situation 4 years later and have summarized these as succinctly as I can.
The Dangling, Damaged Spent Fuel Pools
December of 2014 marked the first truly big recovery accomplishment, with the removal of the last of the new/spent fuel assemblies from the unit-4 SFP and equipment pool. We were not informed about specific damage to assemblies and rods or whether any of them broke during the operations, but it does represent a significant accomplishment in unprecedented conditions. The project involved demolishing what was left of wall supports and roof debris, removing scattered big equipment, and cleaning up the mess on the destroyed refueling floor.
An entirely new facility was designed and built to cantilever over the top story of unit-4 with a nice new crane and cask transfer capability. Delays were quite frequent as the operation moved to new sections of assemblies, for assessment and planning. All in all, the project went surprisingly well. Now all the nuclear fuel at unit-4 has been removed to the common pool, leaving just the ruins and the cantilevered add-on in place.
TEPCO has announced that it plans to begin removal of spent fuel assemblies at unit-3 this year [2015]. Unit-3 was the most extensively damaged plant at the Daiichi facility, and radioactivity levels remain high with readings higher than 0.1 Sv/hr at 'many' locations. The operation will require another cantilevered add-on with a new crane for fuel removal, so it is unlikely that any assemblies will actually be removed this year.
Attempts to remove the original 35-ton fuel handling crane from the #3 pool, where it landed after being blasted into the air by the massive detonation that destroyed the building on March 14, 2011, have been fraught with mishaps connected to the need for workers to use remote control cranes to do the work due to high radiation. In February of 2013 workers knocked the 1.5 ton fuel handling machine into the pool, and in August of 2014 workers dropped the refueling crane console into the pool.
The crane removal project has now been postponed again until April at the earliest, as yet another oops on February 25th of 2015 leaked oil into the pool. Work was halted and the cooling loop servicing the pool was turned off, oil absorbing mats were placed in the pool in hope of removing the bulk of it before it can foul the pumps. So prepping unit-3's SFP for fuel removal has been an on-again off-again project since the beginning. Hopefully the workers operating the remote control machinery are getting somewhat better at it as they go.
Emptying the units 1 and 2 pools is planned over the next 5 years. Toward that goal TEPCO has begun dismantling the modular panel enclosure (what I call a glorified tent) they initially erected over unit-1 to contain radioactivity. A massive hydrogen explosion destroyed the building on the morning of March 12, 2011. Concerns about again sending contamination airborne to re-pollute areas downwind has slowed that project as well.
So far I have seen no reports on the condition of the refueling cranes in units 1 and 2. Unit-2's is likely to be serviceable, unit-1's is more of a question mark. But the fact that neither of those cranes are outfitted for remote control, those cantilevered add-ons may be necessary there as well. When the time comes to start cutting up and removing the reactor vessels themselves and any corium in them or remaining in the containment drywells remote control will be absolutely necessary. So the question applies solely to defueling the SFPs and the levels of radioactive contamination remaining in those buildings as those projects proceed.
The Second Great Contamination Event
During debris removal at unit-3 in the summer of 2013, 3-5 PBqs of cesium (plus considerable alpha and neutron emitters as well as strontium) went airborne and contaminated agricultural fields (and towns) downwind so badly that the foods set off alarms during government testing months later.
TEPCO had not bothered to report those releases, but once the contaminated food was noticed an NRA investigation found that an ill-advised cost-cutting initiative motivated them to over-dulute the spray dust suppressant by a factor of ten. These releases, along with the releases to the ocean from leaking storage tanks, were designated to be additional Level 3 [IAEA] 'accidents' in addition to the original Level 7 designation in 2011. No one has recorded or reported on estimated internal doses to farmers and/or the public under those plumes.
TEPCO has promised to properly dilute and use the dust suppressant according to instructions from now on. For whatever that is worth, given the utility's track record so far and with the Yakuza (organized crime) providing the bulk of the work force. Some of whom have been injured or killed on the job due to corner-cutting on safety basics, and many of whom manage to simply disappear one day and are never seen or heard from again.
Neither TEPCO nor the Japanese and Prefectural governments are counting worker deaths that occur off-site or after a worker's contract is over, and TEPCO has been notoriously remiss even before the 2011 catastrophe in providing protective and monitoring gear to workers, keeping accurate records of worker exposures, and conducting body scans at termination to indicate total internal accumulations.
Thus far inattention to workers' health and safety has been maintained as usual per the nuclear industry in Japan, and shows no signs of becoming stricter just because of the unprecedented dangers present at Daiichi. Given the notable reticence of the Japanese to monitor and report on exposures and health effects to the public as well, we will never know the true cost in human lives and health this disaster will have caused. Which, of course, is just as the industry and its pet governments have always deigned it to be, because if the public understood the true dangers nuclear technology presents they would have insisted upon total shutdown many years ago.
Corium Hide & Seek
Speaking of melted cores, TEPCO is currently attempting to locate remains of the units 1 and 2 cores via muon detectors mounted outside the buildings at the level of the reactor vessels (2nd story). They should be able to assess from these how much of the corium remains in the vessels. Those detectors, however, cannot find anything below ground level at the bottom of the drywells, in the torus rooms, in the underground piping systems or in the ground below the basemats. Neutrons are still being detected in the vicinity, which may at some point allow an assessment of where the bulk of the molten corium flows have congregated, but until the vast bulk of debris - including dust-sized fuel 'fleas', chunks of fuel and pieces of fuel rods - have all been removed to covered pits away from the four destroyed units, neutron radiation will be difficult or impossible to localize for the purpose of locating the corium flows themselves. That sequestration work is ongoing.
Fresh iodine-131 and xenon-133 in air samples confirms that some fission is ongoing, but it is thus far not reported whether this comes from the spontaneous decay by fission of fuel isotopes or from 'flash' fission events on the surface of corium when it is hit by water.
At any rate, the levels of volatile fission products are far, far below those initially released during the height of the disaster. At the present time and for at least the next dozen years the airborne release levels are estimated to be in the range of 10 million Bq/hr, or 240 million Bq/day.
Any attempts to recover corium from the three total meltdowns will probably not begin until around 2025 or later, and will take decades even if everything goes swimmingly. The common fuel handling facility will be receiving all of it, so efforts to cask the older assemblies in that building and moving it to open air storage areas is ongoing. Decommissioning of units 5 & 6 was decided as well. These units were undamaged by the earthquake and tsunami and were off line at the time. They are now being defueled and their SFPs will be emptied in the normal way with their normal refueling cranes and equipment as part of their decommissioning. This spent fuel must also go through processing (if it's ready for dry casking) at the common pool.
Where to Put It All?
Meanwhile, TEPCO has been buying up land in the exclusion zone and plans to use it for storing medium and high level radioactive waste. So far the spent fuel casks - those not containing damaged assemblies - being moved out of the Daiichi common pool facility have been stored at TEPCO's Daini facility ~14 km to the south. All four of those reactor plants remain idled and will be decommissioned as well at some point. Damaged assembly casks from the SFP removal operations at the four destroyed plants is/will be stored at a location between those units and units 5 & 6.
There is not as yet a long term high level (spent fuel) waste repository in Japan (or anywhere else in the world with the possible exception of old USSR sites in the 'stans), nor are plans to build one by the consortium of nuclear nations progressing appreciably. It has been suggested that such a facility may eventually be sited within the forever-contaminated exclusion zone around the Fukushima Daiichi and Daini plants, but it is unlikely they could accept additional high level waste from the stockpiles amassed over the years by Japan's many reactor facilities.
Once the coriums are accessed, cut into pieces and removed from their leaky oceanfront location, those pieces will represent the most dangerously high level of high level nuclear waste in existence. It will of course need to be somehow sequestered from the environment forever. Some imaginative suggestions have included sinking casks into the deepest area of the Japan Trench subduction zone [depth 9,000 meters/ 29,500 feet] off the cost of northeastern Japan, which will eventually carry it into the earth's molten mantle. Of course, that subduction zone's activity - as part of the Pacific Ring of Fire - is what caused the Great Tohoku quake of March 11, 2011. So nobody should be making bets at this point.
The Strontium Problem
As time goes on and as predicted and expected by all who have studied such things, the strontium-90 and 89 released by the three melted nuclear cores at Fukushima has steadily increased its presence. Produced at a general ratio of 1:1 along with the cesium sisters, the strontium presence in the original airborne releases was more like 1:10 due to strontium not being as volatile as cesium. It is, however, more mobile in the environment than cesium over time due to the proclivity of cesium to form bonds with particles of clay and form compounds that help to sequester it on the sea bottom and on land along natural drainage paths. Strontium is more biologically 'available' to accumulate in plants and animals as a calcium mimic, and is known to cause bone cancer and/or leukemias in sufficient concentration. Strontium has a much longer biological half-life than cesium as well, can remain in bones and teeth long after the person is dead. By contrast, the biological half-life of cesium is ~90 days.
Some of the corium contaminated coolant and groundwater in all those hundreds of giant tanks at Daiichi has been filtered with the first and second incarnations of Areva's trouble-plagued ALPS system, the highly contaminated resins from which have their own storage facility now. As of 2014 the tank water is estimated to contain somewhere between 30 and 100 times as much strontium as cesium. WHOI's Ken Buesseler claimed in an interview/article in National Geographic that the tanks contain 100 times more strontium than cesium at this point. PBS NewsHour quoted engineer Arjun Makhijani, president of the Institute for Energy and Environmental Research, figuring just 30 times more strontium than cesium. Given the estimated 212 PBq of cesium remaining in those tanks, multiplying by 30, is more than 6,000 times the amount of strontium-90 released by Chernobyl.
The above analysis is something that everyone interested in the environmental and possible health effects of the Daiichi disaster should keep forefront in their minds when reading something like this from Asahi in September of 2013, two and a half years after the meltdowns/blow-ups. The Japanese Fisheries Agency had, as of the article date, conducted a mere 40 tests on marine products for strontium since the disaster, while 37,470 tests for cesium had been conducted. This is justified by the Japanese government specifically...
The Ministry of Health, Labor and Welfare said it estimates levels of strontium at about 12 percent of radioactive cesium levels.
Which has nothing at all to do with how cesium and strontium behave in the environment and bioaccumulate in the food chain. Worse, it means the food testers are assuming based on inapplicable estimates like this that if the fish has accumulated 50 Bq/kg of cesium-137, strontium contamination should weigh in at around 6-8 Bq/kg. 50 + 6 = 56. 56 is less than 100, so the fish is perfectly safe to eat under Japanese law. Which, by the way, is 10 times stricter than the U.S. on how much radioactive waste you can eat for dinner. Alas, those estimates and assumptions are dangerously misguided in this application.
Analysis of Japanese Radionuclide Monitoring Data of Food Before and After the Fukushima Nuclear Accident [Merz, Shozugawa, Steinhauser; Environmental Science & Technology; January 26, 2015] has a very good explanation of the cesium/strontium ratios and their changes over time, for those who wish to understand the true situation now and going forward over the coming decades (half-lives of strontium-90 and cesium-137 both ~30 years).
...In order to account for the presence of these "inconvenient" radionuclides, Japanese authorities assumed that the pure beta-emitting 90Sr occurs in a constant ratio together with gamma-emitting 137Cs, which can be measured easily. The initial assumption that was reflected in the regulatory limits was based on the experiences of the Chernobyl accident and the fallout of the atmospheric nuclear explosions, [17] assuming an activity correlation of 90Sr : 106Ru : 134Cs : 137Cs = 5.1 : 4.3 : 3 :25.9 : 64.6. This led to the conservative assumption for 90Sr being 10% of the activity concentration of the respective 137Cs concentration in foods. [8] ...
[My emphasis]
Problem is, that in pre-Fukushima samples there was 2 to 10 times as much strontium as cesium in the environment from Chernobyl and bomb testing in the past due to the fate of these isotopes as they move through the environment. Thus the ratio of strontium to cesium now is not the same as it was in the beginning and will continue to change over a period of years as strontium concentrations go higher and cesium concentrations go lower. At some point in the next few years there will (in general) be as much strontium in the food as cesium, and it'll keep on going higher from there.
Foods with activities falling into this area will be falsely permitted although their consumption may be critical. For example, when foods contaminated with 23 Bq/kg 137Cs are consumed over the period of a year (clearly below the current limit of 100 Bq/kg), a 90Sr/137Cs ratio of 2 will already cause a committed dose of 1 mSv. At this activity ratio, a contamination level of 46 Bq/kg 137Cs (less than half of the current limit) will deliver 2 mSv over a year. If we keep in mind that the pre-Fukushima samples often had 90Sr/137Cs activity ratios > 2 (up to 10), this scenario illustrates the potentially severe impact of this erroneous assumption of a constant ratio at 0.1 (or even below).
With the concentration of strontium being released to the Pacific increasing steadily over the past 3 years - and scheduled to increase significantly yet again as the hundreds of thousands of gallons of water in the tanks is released - this is a situation that does have impact on people who consume seafood from the region. The
commercial fishing exclusion zone extends to 30 km offshore. Fish don't care about human drawn lines on maps. So Japan continues to test the food supply for cesium, and occasional samples do come in over the 100 Bq/kg limit. They will continue to assume that strontium is 1/10th to 1/12th of the cesium, even though strontium in the releases has increased in regards to the levels of cesium and will continue to go higher for as long as releases continue.
What Else Is In The Tanks
TEPCO recently gained permission from the government to release tank water directly to the ocean. Tritium cannot be filtered out, so it'll come with. As usual and because there simply exists no way to get the tritium out of million(s) of gallons of water, dilution is the solution to pollution. It's a big ocean, and tritiated water is just water. That's made with radioactive hydrogen. Several hundred other meltdown produced radionuclides that have not been or cannot be filtered out of the water will go on out as well.
~300 cheap bolt-together tanks were erected between 2012 and 2013 to hold the recovered coolant water pumped out of the containments/basements, after underground tanks TEPCO was using (it claimed) failed. One-piece welded tanks make up the bulk of the ~1,200 tanks being used to store water by the end of 2013. Few new tanks have been installed since, as the facility quickly ran out of room to put them. Now they are using huge bladders instead, and workers report that all of them are leaking. Thus the tank & bladder farm is and always has been a mere temporary way station for the corium contaminated coolant on its way to the sea.
Water in the lagoon directly seaward of the 4 destroyed reactors is tested regularly, and is significantly contaminated (levels fluctuate some) with everything from transuranics to tritium, inclusive, of fission/meltdown produced isotopes plus radioactive sodium from the salt water they were using in the first couple of months to not really control the meltdowns. The bottom has been 'sealed' with a marine concreting material twice, but contaminated trench water has been leaking directly over and through the wall all along and has not yet been stopped.
Water leaked/released from the conduit trenches and water storage tanks follows the site contour perimeter drainage "ditch" south of the harbor lagoon and seawater discharge canal (condenser coolant). Heavily contaminated rainwater from the roof of unit-2 (the only plant of the four that still has a roof) has been draining for years into the perimeter drainage "ditch" on the north side of the facility as well. TEPCO does not allow independent sampling of discharge at any points along the coastline all the way to the southern perimeter boundary of Daini - a stretch of nearly 20 kilometers. Thus we have only the corporation's word on how much is going out and how hot the water close to shore may be. Hence it is pertinent to note here that the exclusion zone is not just inland of the Daiichi facility, but also continues 30 kilometers offshore with a voluntary ban on commercial fishing extended to 100 km.
And About That Groundwater...
The groundwater underneath the plants is reflecting the same thing. TEPCO has deployed strontium filter systems to treat the tank water, which includes groundwater pumped out of the lower levels of the plants, where it flows through earthquake caused cracks in the walls and around piping. This is aquifer water that flows from the mountains to the west like an "underground river" directly beneath the plants and from there through ancient sinks following fossil faults bisecting the offshore shelf and into the Pacific Ocean beyond (past the Daiichi harbor seawall but well before the trench drop-off). It picks up corium contamination from the coolant poured in to the bottomless reactor vessels that follows gravity (and corium) into the basements, and significant portions of the corium flows themselves are suspected to have gotten below the first basement torus level via piping and drains.
Beyond that, there is much more groundwater flowing through and becoming corium contaminated than TEPCO can pump out and put into tanks. That water with high radiation levels (millions and billions of Bq/liter) flows under and through the cliff-front seawalls, rises from sinks beyond the harbor into the ocean at a rate of 300 - 400+ tons a day. Every day, for years. Cesium levels may be somewhat filtered via bonding with clay by the time the water comes up on the seafloor, but the strontium is still there. And of course the tritium. And other isotopes.
TEPCO and its industry allies have come up with some imaginative methods of trying to prevent the groundwater from going over and/or out of the wall or up through the sinks. At first it was a linking sheet metal coffer dam. But they ended up having to use those panels to cover the ground around the plants so workers could get from here to there without stirring up dust, collecting mud, or getting steamed by fumeroles that began hissing in the summer of 2011. Then it was the big freeze wall. Which is still not completed but they did turn on the upstream section this month just as they finished that section of the secondary zeolite pit-barrier. I'm not convinced freezing the ground is going to work long term, but zeolite is a useful improvement. It will bind radionuclides (like a charcoal filter). And will have to be refreshed regularly if they ever manage to extend it around and between the plants and the sea. The water coming in on the inland side isn't that contaminated. Hope they've got some big-ass Shop-Vacs on order, and a big pit to bury the zeolite in.
Truths That Have Come To Light
TEPCO keeping important information to itself or flat-out lying to everyone keeping track (including government regulators and IAEA) didn't begin in the summer of 2012 when they stirred up a lot of deadly dust to remove debris from the top of unit-3. Why, right at the beginning of the disaster they started telling lies about what was going on, pretending ignorance of actual conditions, and hoping nobody would notice. One of the footnoted findings from the official National Diet report on its investigation of the disaster (July, 2012) identified serious problems both with monitoring of radioactivity levels and communication of those to the responding agencies local, prefectural and national.
As the seriousness of contamination did become known, it was clear that the amount of radionuclides released from 3 total meltdowns and 4 exploding reactor buildings (complicated by several spent fuel pool fires that burned off and on for days) had been underestimated by all. The range of estimates from various investigations over the years have ranged from TEPCO's ridiculously low "less than 50% melt in only one reactor" crap to truly scary numbers many times higher than Chernobyl. As always when dealing with nuclear oopses, it depends entirely on who you ask.
A January, 2015 report from NHK analyzed last year's tardy information from TEPCO and the NRA indicating that seawater injected into the reactors through fire hoses in the first weeks to try and stop the meltdowns largely failed to get any water into those reactors. The hoses had been hooked up to exterior piping because no one could go in and hook it to the RCS proper, and in-line check valves shunted most of it into the turbine buildings (where it leaked out and flooded them). TEPCO admitted "most" of the water didn't make it. NHK quantifies that - 30 metric tons per hour was injected, but only 1 metric ton per hour made it to the reactors. Or, about 4.4 gallons per minute, a less than full 5-gallon bucket's worth.
Such a small amount of water actually caused the temperatures to climb, sustaining the meltdowns, throwing immense amounts of neutrons out willy-nilly, and lengthened the period of greatest releases to the environment for weeks. Turns out that only 25% of the original - and largest - Fukushima releases escaped in the first 4 days, while 75% escaped over the remaining weeks of March, 2011.
We see quite a few scientific studies linked here at DKos dealing with radiation monitoring of the Pacific off the coast of eastern Japan and off the west coast of Canada and the U.S., and have seen some colorful computer modeling maps and animations. We've seen much about expected levels and measured levels in the water and in seafood, and early on we saw a lot about the atmospheric plumes, the EPA's RadNet monitoring snafus, and predictions on health effects that may result. Most of these, just like the UNSCEAR report on Fukushima are based on the nuclear industry's disinformation that more than 90% of environmental (air and water) releases occurred in the first 4 days of the disaster. Something now known not to be true.
On October 24th of 2014 a letter was hand-delivered to the UN and UNSCEAR in New York City requesting revision of their report in light of new information, and a new UN mandate for the United Nations Scientific Committee on the Effects of Atomic Radiation [UNSCEAR]. The letter was signed by 43 civil society groups from 9 countries, including 21 groups based in Japan. The letter was accompanied by a careful critical analysis of the UNSCEAR report by the IPPNW [International Physicians for the Prevention of Nuclear War], an organization which was awarded the Nobel Peace Prize in 1985...
Current research gives no justification for such optimistic presumptions. Although UNSCEAR's evaluations of the complex data may be useful in assessing the consequences of the Fukushima nuclear catastrophe, we also feel that the report does not reveal the true extent of the consequences of the disaster. The Belgian Association for Radiation Protection, a member of UNSCEAR, criticized that the report has even retreated from the lessons of Chernobyl. UNSCEAR draws mainly on data from the nuclear industry's publications rather than from independent sources and omits or misinterprets cruicial aspects of radiation exposure. In question are also some of the assumptions, which UNSCEAR's calculations are based on. Even a month after publication of the report, the important appendices containing the raw data have still not been made accessible, preventing independent verification of UNSCEAR's conclusions. For these reasons, doctors from 19 affiliates of IPPNW have found the need to issue this critical analysis of the UNSCEAR report.
Emphasis mine
IPPNW's criticisms are based on 10 basic arguments:
1. The validity of UNSCEAR's source term estimates is in doubt.
2. There are serious concerns regarding the calculations of internal radiation.
3. The dose assessments of the Fukushima workers cannot be relied upon
4. The UNSCEAR report ignores the effects of fallout on the non-human biota.
5. The special vulnerability of the embryo to radiation is not taken into account.
6. Non-cancer diseases and hereditary effects were ignored by UNSCEAR.
7. Comparisons of nuclear fallout with background radiation are misleading.
8. UNSCEAR's interpretations of the findings are questionable.
9. The protective measures taken by the authorities are misrepresented.
10. Conclusions from collective dose estimations are not presented.
...and these arguments are explained in detail. It's worth a read, because just the childhood thyroid cancer rate in Fukushima prefecture belies UNSCEAR's unicorns and rainbows dismissal of the worst nuclear disaster the world has yet seen.
So this is where things stand with the Fukushima nuclear disaster four years later. Thanks for reading. If you are interested, some background links are offered below.
More:
SimplyInfo: Fukushima Disaster Four Year Report
Fukushima Unit-2 Full Report
Analysis of FOIA documents [NRC, DOE]: March 11 through May, 2011 -
Fuku FOIA Docs 1: Who Knew What When?
Fuku FOIA Docs 2: I Feel Like Crying
Fuku FOIA Docs 3: Heavily Redacted
Fuku FOIA Docs 4: A Marathon Not A Sprint
Fuku FOIA Docs 5: Did We Know This?
Fuku FOIA Docs 6: Your Career Likely Over
Fuku FOIA Docs 7: We Made The Onion
Fuku FOIA Docs 8: A Real Outrage