Fukushima's ground zero: No place for man or robot
reuters.com
reuters.com
- High radiation concentrations in new leaves, and at least in the case of cedar, in pollen;
- apparent increases in growth mutations of fir trees with rising radiation levels;
- heritable mutations in pale blue grass butterfly populations and DNA-damaged worms in highly contaminated areas, as well as apparent reduced fertility in barn swallows;
- decreases in the abundance of 57 bird species with higher radiation levels over a four year study; and
- high levels of caesium contamination in commercially important freshwater fish; and radiological contamination of one of the most important ecosystems – coastal estuaries.
http://www.greenpeace.org/international/en/press/releases/20...
None of that is remotely as damaging to the natural environment as continued human habitation of the area that has been evacuated. Cry not for the fishes and birds, for they are better off with slight genetic damage than they are with us.
The threshold at which people become uncomfortable about radiation is several orders of magnitude lower than the threshold at which it causes population decline in wild populations, and people cause declines and extirpations in wild populations all the time.
Of course the people displaced from the area didn't disappear, they're affecting wildlife somewhere else. Seems like mostly zero sum in that specific regard.
At best, we can establish areas that look roughly like they used to look before humans, but this is no less deliberate design than the styrofoam rocks at the zoo, it's just on a different scale. Many such areas are, in fact, better seen as zoos, because of their small size or limited variety. Most of the productive arable land is predictably already being used for something by somebody.
Personally, I'm a humanist. The worst things environmental devastation can do to us are disrupt some of our services, like agricultural collapses; After that environmentalism is mostly a romantic or novelty-based aesthetic, albeit an attractive one. Pit it against human lives and human profit, and groups of humans will nearly always make the same decision.
EDIT: Worth tacking on, for some perspective: https://xkcd.com/1338/
Creating our homes in a more ecological and recycleable way would be in perfect harmony. The arguement is whether we should go further and drastically change the enviroment, do we have the right as the dominant species on the planet to abuse its resources for ourselves (as seen in the attached xkcd whose figures roughly show the populations of mammals who we have artifically inflated to such proportions for our dietray wants).
So if we changed our architechture and agriculture then yes we could live in perfect sync and harmony, it's just that we wont.
If you want to re-establish the wild ecology of ~4000 years ago? You need to get the people out. Modern human habitation & agriculture claims a right to every last square meter of land, and even the supposedly reserved natural areas are often cut & planted as if they were pseudo- lumber factories.
If this is your goal, irradiating wide swathes of land is a good start; There are few simpler or more reliable mechanisms to force sustained evacuation and shunning of an area for the centuries or millennia necessary to re-establish, for example, old-growth forest. Some legal regime might buy you a few decades, but don't kid yourself about the longevity and commitment of a particular political system.
The changes in species composition associated with the climate, then with megafauna, and later with the Columbian exchange & globalization, are going to pose some durable problems if you want it to look exactly the same, but you can form a complex ecology with most of the same niches filled with at least similar creatures.
Wild animals need a threat thousands or perhaps tens of thousands of times higher to actually threaten their ability to sustain themselves. All they need to keep the population up is replacement-level fertility on average, and most animals are physically capable of many, many times that level.
In this higher dose scenario lifespan is reduced so much that it starts to impinge on their reproductive capabilities, which are usually food/habitat limited by human influence (or previously to humans, by predators and disease as well).
Humans made a tradeoff towards k-selection: in order to support these huge skulls & brains, we made childbearing an epic process that takes a decade, and made childbirth quite dangerous. For something like heavily r-selected fish, two parents might produce ten thousand eggs, and only two of them need to survive to breed to sustain the population. Remove all the other things that kill this example fish, and each generation is five thousand times the size of the previous generation. Most mammals are somewhere between fish and humans.
Free up the habitat and let them reproduce ad libitum, and over all but the worst-hit areas, wild animal populations will grow rapidly because the radiation is less of a population stressor than the people, their cars, their pavement, their agriculture, and their fishing nets were.
This was not an expected result. The efficacy of Chernobyl as a wildlife preserve was kind of a wake-up call for ecologists about how deep into the anthropocene epoch we actually are.
I'm sure Greenpeace reports are biased but probably not more than studies by people who want to stuff nuclear power plants into private homes.
Absolutely. I would even suspect intent to deceive, as is so common with anti-nuclear propaganda. People have not been harmed to an alarming extent by this event, as they certainly were with Chernobyl. The reactor is a completely different passive-safe design. In all probability long-term damage will be limited to some hard-to-attribute secondary effects (changes to the land use patterns in the region will confound statistical analysis), and of course, massive psychological devastation due to all the panic and misinformation. Sadly this is by far the greatest threat posed by modern nuclear power (or rather the cultural context in which it is placed).
If the Japanese government would legally allow me to live next to the reactor I would take them up on it tomorrow.
160,000 people were displaced and will live in school gyms for the rest of their lives. Most have lost their livelihoods.
I suggest you talk to them before saying they have "not been harmed."
1. people might get harmed by the radiation (true)
2. evacuate them (still arguably sensible)
3. radiations caused harm because people were evacuated
> The Fukushima disaster is the single largest release of radioactivity into the ocean and one of only two Level 7 nuclear disasters in world history - the other being Chernobyl.
So, can you explain what is so wrong or inane about this statement? I think it's rather informative and to the point, tbh.
As far as I can tell, so far the "Level 7" category is useful mainly to cite in this very argument. Surely we can do better, are there at least some individual score factors?
1 - http://www-ns.iaea.org/tech-areas/emergency/ines.asp [2] - http://www.sciencedirect.com/science/article/pii/S0048969713... (2014, but I'm not aware of revised figures from the past two years)
I mean, they don't need Atlas here. They just need a ruggedized remote control car with a camera and a ton of lead plate on it.
robots, which can swim under water and negotiate obstacles in damaged tunnels and piping to search for the melted fuel rods.
to find and remove the extremely dangerous blobs of melted fuel rods, weighing hundreds of tonnes
You don't need a hundred-tonne robot to find a fuel rod, so they can at least get that part sorted. Once they know where they are, build something super rugged (I'm thinking basically a remote controlled shielded fork lift) to do the lifting.
Certainly if the answer was actually as simple as "buy this off the shelf thing" then all the smart people over there would've figured that out at some point in the last 3 years.
It's a complex process. They can't risk creating a situation worse than before, and nuclear facilities are pretty sensitive.
They usually create 1/4 scale models of the buildings they'll be working with for testing, etc. - it's a big deal.
The Fukushima reactor was built to withstand a huge amount of risk factors, they just all happened at the same time. The risk mitigation concept would be to say that you need to design a house to withstand a 10,000 year storm.
We do build mock facilities and we have recently started working on the Fukushima Daiichi inspections, and there is only so much I can actually say but I'll share what I can. I'll explain what caused the failure in this part and then I'll move onto the fun stuff in the next post (robots!).
In the past, the mock facilities we have made in the past were a quarter of a full scale reactor, rather than a quarter scale reactor, if that makes any sense at all.
Anyway back to Japan. I'm assuming people have a basic understanding of how fission reactors work (Boiling Water Reactors if you are interested in doing further reading).
To break the situation down, the cooling failed (believe it or not, diesel generators don't work too well on water!) on reactors 1, 2 and 3, causing a complete meltdown of the fuel rods. When cooling failed, all of the cooling water was turned into steam, which in turn reacted with the released radioactive isotopes creating hydrogen. I'm assuming people know mixing hydrogen with oxygen is basically a recipe for an explosion, and that is important for what happened next. They tried to vent the gases out to the atmosphere to prevent the pressure vessel from exploding, but the hydrogen went the wrong way and caused reactors 1 through to 3 to explode in various places. I can't remember correctly (I think its reactor 3?) but the explosion happened within the pressure vessel which is why there was a large contamination breach. Because of this complete loss of control of the reactors, and the meltdown currently happening, they flooded the whole system with sea water and pumped as much out into storage as they can, but they lose a lot of it out to the sea, hence the Americans whining about the radiation in the Pacific. Now, the reactors are stable (ish) and they are continuing to pump water in to stop them going critical again.
I'll move onto the robots when I get home in part two, but right now I need to go have an argument with a lawn mower as my hair is getting unruly. The video linked below explains more about the actual failure of the reactor:- https://www.youtube.com/watch?v=JMaEjEWL6PU
Brb.
AFAIK, fukushima was actually a very small "disaster", with negligigle human life loss (if I recall correctly, no life loss, except due to the evacuation panic)
Would you, in conscience, turn back on a series of nuclear reactors that had their emergency backup generators located in an area that can easily be flooded?
There are a lot of other human/social aspects involved as well.
It's better to apply the lessons learned from Fukushima to a safer type of reactor, built better, designed safer, and operated with a different set of procedures and by a different company (not TEPCO, for example).
1) in the past the mocks was just a subset portion of the reactor (ie the quarter that is relevant to operations)
Hopefully I didn't mangle your words, but this is how I understood your phrasing.
In terms of Fukushima, the manipulator we are developing will eventually have a testing rig built for it, however we have only just been involved on the project in the last month and as such haven't reached a stage where we need to build the rig yet. With the Japanese government funding though I imagine it will be a similar job with a scale rig.
So, ROVs.
We probably aren't going to use a ROV for our solution as it doesn't suit and they're a pain in the arse quite frankly.
To start, I'll address the issue with the 'wires' failing. An American company built a ROV that was heavily shielded and was driven via an umbilical. Wireless is hard to use and autonomy is too hard to use as the reactor conditions are unknown. The ROV was a good design and could survive the radiation for a reasonable amount of time, however for whatever reason they used PVC wire sheathes that break down under heavy radiation, and as a result the wires touched and shorted the electronics out, rendering the ROV useless and 'dead'.
In terms of why it takes so long and why we can't use an off the shelf version, basically radiation is a bitch. At the base of the reactor vessel, just above the corium, the radiation output is estimated to be around 3000 microsieverts per hour, that translates roughly to a human life expectancy of around 6 seconds, give or take. This amount of radiation causes electronics to fail (transistors commonly), and materials to break down. The breaking down of materials caused the American ROV to die, and another example would be that it can causes greases to harden, which stops motors working.
Reactors aren't big spacious areas either, so it's not like we can just deploy a lead (lead weighs a metric shit'tonne) shielded tank to have a look, it's just too big and cumbersome. We decided against using a ROV as it had to be 30kg or less, which is absolutely nothing once you bring in drilling packages and the likes.
Also quite often you will be deploying through a hole between the size of your fist up to just smaller than the diameter of your head, so that restricts you hugely as well.
You also have material compatability. If you get something stuck you have to be sure that it won't react and cause the reactor to become critical again, which could happen in one of the reactors (can't go into more detail sorry).
One last major consideration as too why it takes so long to build and test a ROV to suit. The reactors are under immense thermal stress, and metal likes to bend and warp when it's heating/cooling. You have to build your solution around the worst case scenario. An example would be we went into a boiler tube trying to plug a 1 inch hole from 18m above it using a manipulator arm. That's already hard on its own, but then we discovered the originally 7mm gap we were aiming for was actually now as small as 3.5mm. Trying to develop ROVs and remote solutions is really not easy, the best way I can put it is that this line of work is an art, not a science. That's why it will probably take the best part of a century I reckon to fix this problem.
That's why it will probably take the best part of a century I reckon to fix
this problem.
But a question -- you say you won't use a ROV. But you say wireless is hard and autonomy is too hard. So that leaves what?
And thanks for taking the time to share.
Also we are going to use a manipulator arm more than likely. Manipulator arms are cheaper and more widely used in our industry.
Your idea would be perfect if we were just doing an inspection, however we have other work we will need to do down there which will require various packages so it has to be somewhat bulkier.
3000 microsieverts (3 milisieverts) is most definitely not fatal, as it is similar to the yearly exposure.
Sorry?
There are gases circulating around, free hydrogen gas, volatile gases that could explode if exposed to a spark - so the robot has to be built to not spark or have inert mechanisms for turning, moving, etc.
Parts are submerged, so this robot needs to be water tight to irradiated water and have some mechanism of moving when submerged (buoyancy control).
Radiation is the highest danger to electronics, it's said that all the wires degrade, all the parts of the robot steadily break down when trying to get inside. The chips and control circuitry needs to be radiation hardened, and I bet the "wires" the article refers to means servo control wires - which needs to be linked to servos that are on the limbs - so it's harder to shield. (whereas control chips, the cpu, etc can be shielded by lead plates in a central location)
In all seriousness, radiation shielding (necessary thickness of metal, etc) is quite well understood. It's probably not even an especially hazardous cargo compared to what most tankers haul.
Depending on who "owns" the waste, its handling and disposal is regulated differently. " In 10 C.F.R. § 20.2002, the NRC reserves the right to grant a free release of radioactive waste. The overall activity of such a disposal cannot exceed 1 mrem/yr and the NRC regards requests on a case-by-case basis. Low-level waste passing such strict regulations is then disposed of in a landfill with other garbage. Items allowed to be diposed of in this way are: glow-in-the-dark watches (radium) and smoke detectors (americium) among other things."
https://en.wikipedia.org/wiki/Low-level_waste
"Low-level waste (LLW) is nuclear waste that does not fit into the categorical definitions for intermediate-level waste (ILW), high-level waste (HLW), spent nuclear fuel (SNF), transuranic waste (TRU), or certain byproduct materials known as 11e(2) wastes, such as uranium mill tailings. In essence, it is a definition by exclusion, and LLW is that category of radioactive wastes that do not fit into the other categories. "
Of note, there is no exclusion for naturally occurring radioactivity.
The sea has extractable uranium in it already, and the volume of water is pretty much a literal drop in the ocean.
http://www.tepco.co.jp/en/nu/fukushima-np/info/images/130529...
[1] http://acselb-529643017.us-west-2.elb.amazonaws.com/chem/243...
[1]http://hopefullyintersting.blogspot.com/2013/12/fukushima-vs...
It's also interesting that the fishing industry, which is usually (correctly) assigned blame for depleting fish stocks is, in this case, protecting fish habitat.
I guess nuclear contamination is in a different category than say, pollution from coal burning power plants, which add a lot of mercury to the environment which then ends up in high level ocean predators like tuna. The fishing industry doesn't seem to have the ability to stop that kind of pollution.
Maybe it's because many sea food consumers people casually ignore mercury levels in fish they eat. Or maybe it's because the Japanese seafood supply chain is well enough managed and regulated that people really know where a piece of fish in a market actually came from. Perhaps people carry geiger counters into the supermarkets there. I don't know.