Six Years After Fukushima, Robots Finally Find Its Reactors' Melted Uranium Fuel (gizmodo.com)

An anonymous reader quotes Gizmodo: Earlier this year, remotely piloted robots transmitted what officials believe was a direct view of melted radioactive fuel inside Fukushima Daiichi Nuclear Power Plant's destroyed reactors [YouTube] -- a major discovery, but one that took a long and painful six years to achieve... Japanese officials are now hoping that they can convince a skeptical public that the worst of the disaster is over, the New York Times reported, but it's not clear whether it's too late despite the deployment of 7,000 workers and massive resources to return the region to something approaching normal.

Per the Times, officials admit the recovery plan -- involving the complete destruction of the plant, rather than simply building a concrete sarcophagus around it as the Russians did in Chernobyl -- will take decades and tens of billions of dollars. Currently, Tepco plans to begin removing waste from one of the three contaminated reactors at the plant by 2021, "though they have yet to choose which one"... Currently, radiation levels are so high in the ruined facility that it fries robots sent in within a matter of hours, which will necessitate developing a new generation of droids with even higher radiation tolerances.
Friday a group of Japanese businesses and doctors sued General Electric of behalf of 150,000 Japanese citizens, saying their designs for the Fukushima reactors were reckless and negligent.

Comments

Fukushima was older than Chernobyl

[jez9999]

I always like to remind people that this thing was older than Chernobyl. This was NOT a modern nuke plant with decent safety features that went meltdown. There is no comparison.

Re:Fukushima was older than Chernobyl

[Anonymous Coward]

I like to remind people that practically all nuke plants are old and don't have decent safety standards, and that it will always be this way because nobody likes to decommission an expensive nuclear power plant if it can be kept online just a little bit longer. Hence Fukushima.

Re:Fukushima was older than Chernobyl

[b0s0z0ku]

Even so -- it melted down. It didn't catch fire and burn for weeks like Chernobyl, because GE designers weren't insane enough to put graphite in close proximity to superheated steam. C + H2O -> H2 + CO

Chernobyl was actually an older class of reactor, even though it wasn't physically older than Fukushima. Based on 1940s plutonium production reactors (and likely, a secondary design consideration was production of plutonium from natural uranium), not really a civilian design.

The Chernobyl design has a few advantages like ability to be refueled while in use (each fuel element had its own steam/water tube that could be isolated) and ability to run on unenriched uranium. But those were outweighed by the disadvantages of the basic design, lack of containment, and poor execution (control rods that increased power when first inserted due to poor design!).

Interestingly, reactors with the same design as the failed Chernobyl plant are still running in Russia proper, though the plants in the former republics and satellite countries have been shut down.

Re:Fukushima was older than Chernobyl

[boudie2]

The following 23 U.S. plants have GE boiling-water reactors (GE models 2, 3 or 4) with the same Mark I containment design used at Fukushima, according to the NRC online database:
Browns Ferry 1, Athens, Ala., operating license since 1973, reactor type GE 4
Browns Ferry 2, Athens, Ala., 1974, GE 4
Browns Ferry 3, Athens, Ala., 1976, GE 4
Brunswick 1, Southport, N.C, 1976, GE 4.
Brunswick 2, Southport, N.C., 1974, GE 4.
Cooper, Brownville, Neb., 1974, GE 4.
Dresden 2, Morris, Ill., 1970, GE 3.
Dresden 3, Morris, Ill., 1971, GE 3.
Duane Arnold, Palo, Iowa, 1974, GE 4.
Fermi 2, Monroe, Mich., 1985, GE 4.
FitzPatrick, Scriba, N.Y., 1974, GE 4.
Hatch 1, Baxley, Ga., 1974, GE 4.
Hatch 2, Baxley, Ga., 1978, GE 4.
Hope Creek, Hancock's Bridge, N.J. 1986, GE 4
. Monticello, Monticello, Minn., 1970, GE 3.
Nine Mile Point 1, Scriba, N.Y., 1969, GE 2.
Oyster Creek, Forked River, N.J., 1969, GE 2.
Peach Bottom 2, Delta, Pa., 1973, GE 4.
Peach Bottom 3, Delta, Pa., 1974, GE 4.
Pilgrim, Plymouth, Mass., 1972, GE 3.
Quad Cities 1, Cordova, Ill., 1972, GE 3.
Quad Cities 2, Moline, Ill., 1972, GE 3.
Vermont Yankee, Vernon, Vt., 1972, GE 4.
This was from five years ago. Didn't check to see how many ar still operational but they're definitely old.

Re:Fukushima was older than Chernobyl

[Solandri]

The nuclear parts of the plant itself survived both the earthquake and tsunami just fine even though both events were well beyond the plant's design specifications.

The failure was loss of power to run the plant's cooling systems. Basically, the tsunami swamped the backup power generators and contaminated the diesel fuel reserves for the generators. The destruction of the surrounding roads prevented new generators and fuel from being brought in in a timely manner. And when they eventually did arrive, workers discovered the power couplings for the trucks were different from the ones the plant used, and they had to gerry-rig a connector. All of this took critical time which could've mitigated the severity of the accident. This wasn't an explosion like Chernobyl, it was a gradual event as the cooling water slowly evaporated allowing the fuel rods to melt.

A single diesel generator situated on higher ground with an independent fuel source could've prevented the entire accident. Instead, in stereotypical Japanese fashion, they placed all the generators in a neat row right next to each other in the basement, where the tsunami swamped all of them simultaneously. See, the thing about redundant backup systems (e.g. multiple generators in case some do not function) is that they have to be different to be redundant. If they're the same model, in the same location, using the same fuel source, then any single event which affects one generator will affect all the generators, defeating their redundancy. In fact the two newer reactors at Fukushima on higher ground were just fine because their generators and fuel supply worked as intended. They just didn't have a really long extension cord to reach from those generators to the problem reactors. Basically the failure at Fukushima was the same as when you store your backup drive next to your computer (although the consequences were much more severe). If your house burns down or you're burglarized, both your computer's main drive and your backup drive will be lost. Because you're storing both in the same location, the redundancy of a second copy is defeated by any event which affects that entire location.

Fukushima wasn't a failure of nuclear power. It was a failure of backup (non)redundancy which had nuclear consequences. Basically, because of unwarranted paranoia about nuclear power, everyone concentrated on going over the nuclear parts of the plant with a fine-toothed comb to make sure it was safe. As a result, the non-nuclear backup systems didn't get enough scrutiny, and that's what failed.

It's like airliner safety. Air travel is already far safer than other modes of transport. But because any airplane crash gets disproportionate news coverage, we spend billions of dollars trying to reduce the couple hundred airliner deaths per year even further. Meanwhile the tens of thousands of people dying each year in car accidents gets very little attention. Even including the estimated future cancer deaths from Chernobyl and Fukushima, nuclear power is still the safest power source we've invented (yes, safer than wind and solar based on both on deaths and lost man-days per unit of electricity generated).

Re:Fukushima was older than Chernobyl

[AmiMoJo]

The nuclear parts of the plant itself survived both the earthquake and tsunami just fine even though both events were well beyond the plant's design specifications.

That is incorrect. The plumbing for the cooling system was damaged by the earthquake. The tsunami damage made it impossible to check it in the aftermath, and the fault went unnoticed until it was too late.

That fault, specifically a key valve stuck in the wrong position, meant that the water that was pumped in to cool the reactors from fire engines was diverted to storage tanks. If it had reached the reactors then the explosions and meltdowns might have been avoided.

Fukushima wasn't a failure of nuclear power. It was a failure of backup (non)redundancy which had nuclear consequences.

To two are inseparable and for all intents and purposes one and the same.

But because any airplane crash gets disproportionate news coverage, we spend billions of dollars trying to reduce the couple hundred airliner deaths per year even further.

Is it that, or is it because the potential consequences of a disaster, like an aircraft going down over a city, are very serious? Also, the cost is relatively small compared to the profitability of running an airline. The main issues they have are fuel/pollution, noise and airport capacity. Safety costs come pretty far down the list.

Info...

[XSportSeeker]

I'll just repost my comment from Gizmodo here, some info to kill some potential myths.

It’s bad, and it’ll probably take a long time to be solved... ultimately getting to some point similar to Chernobyl. Not in the same scale I mean, but like years from now they’ll just encase the whole thing in concrete and abandon it there because there’s not much else to do.

Let me tell something about this for people that might be reading and getting a wrong picture out of it, because I also did and just learned recently about some stuff. People should know that for the vast majority of Fukushima prefecture, life remains going like normal. The area affected that people had to evacuate was a radius of around 20 to 30km (12 to 18 miles), which is of course still a lot, but just a small fraction of Fukushima as a whole, which has almost 750 square kms (288 square miles).

It’s nothing to laugh about, but I think some people imagine something like the entire prefecture, or half of Japan being a radiation infested zone or something. Fukushima is the 20th out of 47 prefectures in terms of population, 3rd in area, the capital city wasn’t affected.

I was watching a channel that made a tour around major onsen cities in Fukushima, awesome stuff. Radiation wasn’t a concern, even when they went to a coastal city about an hour away from the power plant.

Again, it’s not to diminish how serious the disaster is, but the thing is, we get a whole lot of reports talking only about the disaster zone, so much that it seems that it’s a huge area that is unlivable. It’s not.

The citing of the plant was certainly negligent

[dfenstrate]

Fukushima's site was dug down to make it easier to build. Just up the coast, closer to the epicenter, Onagawa was built higher above the water line, and they even included a basin to maintain an ocean water supply to the safety related pumps for the duration of a tsunami. They escaped the Earthquake and Tsunami largely undamaged. In fact, Onagawa actually served as shelter after the Tsunami.