"We can’t see inside Fukushima Daiichi because all our robots keep dying"

[wraper]

Look at the noise on the video as radiation increases.

[wraper]

There a robot failures on the video, exposure for 10 minutes at shown radiation is enough to kill you in a week.

[mikeselectricstuff]

The dark color at X-ray tubes can also be cause from the electron beam cracking oil or sputtering off some metal. The normally rather soft x-ray is not that likely to cause defects in the glass that turns it dark. However the higher energy radiation in the reactor might be able to do that.

X-ray tubes typically start off dark brown - this is to make the glass very slightly conductive to avoid problems due to surface charges building up and messing with the electron optics.

[TimFox]

So if lead reduces the effects of the radiation why can we not make a labyrinth of lead and a quartz window for the camera. I have seen documentaries of special nuclear reactor defueling machines that have concrete and lead labyrinths to keep this issue at bay. There would not really be that big of an issue with weight of your robot because we are not going to space and weight is not "really" a limiting factor. You may need a fairly beefy umbilical coated in lead shielding and on board power batteries for the robot. In my day dreaming of future projects would be a mining robot to use on mars for the Space X refueling system. This would face a similar radiation issue not as bad but still troublesome.

Note that lead is an efficient shield for alpha, beta, and gamma radiation, but not for neutrons.  Concrete, water, polyethylene (especially borated), and other hydrogen-containing materials are good for neutrons.

[Assafl]

There may a much simpler engineering problem at work here.

Instead of Sieverts, the problem at stake may be in Yen. Tepco might just want more money.

The "robot dying" story is a cute way to get public empathy for taking a larger stake from the public coffer.

Do you drink conspiracy kool-aid?

https://en.wikipedia.org/wiki/Radiation_hardening

If by conspiracy you mean looking for funding - I guess I am. There is no shame (nor "conspiratorial" intent) - just that they'd need to buy more robots.

I am sorry if the original texts strike me as "wanting". For example, I am sure you are used to rads for measuring the exposure a chip has to radiation. But the radiation these poor robots get exposed is expressed in Sieverts. Sieverts are used for humans (damage to biological tissue). Perhaps androids too. But not robots. (Are the robots androids? If they are I am missing a vastly bigger picture here.)

It would be nice if they stated what parts failed, the radiation exposure dose that these parts that failed had, and what protection did they use (lead box, etc.).

As for money - if they need more robot parts - it will cost more money. And these are not cheap robot parts (using radiation hardened components).

If by conspiratorial - you mean however, believing that Obama would tap Trump? Nope.

[james_s]

The dark color at X-ray tubes can also be cause from the electron beam cracking oil or sputtering off some metal. The normally rather soft x-ray is not that likely to cause defects in the glass that turns it dark. However the higher energy radiation in the reactor might be able to do that.

X-ray tubes typically start off dark brown - this is to make the glass very slightly conductive to avoid problems due to surface charges building up and messing with the electron optics.

Hmm I have a couple that have a noticeably brown patch everywhere the glass is directly exposed to radiation, although I suppose it could be evaporated tungsten from the anode. Somebody told me once that it was caused by the radiation and I never bothered to question that.

[Vtile]

It would be nice if they stated what parts failed, the radiation exposure dose that these parts that failed had, and what protection did they use (lead box, etc.).

Indeed it would be nice to know what happened to those robots, but I wouldn't be too suprised if that knowledge is protected as a trade secrets. In that sense you are right, even disasters are a good business for some. That said, I haven't looked the subject and my tendency for pessimism cynicism might trick me here.

[wraper]

It would be nice if they stated what parts failed, the radiation exposure dose that these parts that failed had, and what protection did they use (lead box, etc.).

First of all, failed robots were abandoned. So there is no way to check what exactly has failed. And even if they were recovered, checking them is not a trivial task as they became radioactive as hell. You cannot just go and poke them because you won't live that long after that.

[wraper]

I am sure you are used to rads for measuring the exposure a chip has to radiation. But the radiation these poor robots get exposed is expressed in Sieverts. Sieverts are used for humans (damage to biological tissue). Perhaps androids too. But not robots. (Are the robots androids? If they are I am missing a vastly bigger picture here.)

Just LOL, do you think they are particularly concerned about the radiation robots are exposed at  ? Or, just maybe, about radiation which impacts humans?
EDIT, and BTW:

The rad is a deprecated unit of absorbed radiation dose, defined as 1 rad = 0.01 Gy = 0.01 J/kg.[1] It was originally defined in CGS units in 1953 as the dose causing 100 ergs of energy to be absorbed by one gram of matter. It has been replaced by the gray in SI but is still used in the United States, though "strongly discouraged" in the chapter 5.2 of style guide for U.S.

So yeah, US is special one, the same as with inches.

[Assafl]

Okay - I follow that the gray unit is better as an SI unit. my point was the use of Sieverts with a robot.

And my point about Androids was a slight referral to science fiction (like Phillip K. Dick). Obviously these are not androids. Just a camera mounted on a remote controlled robotic body.

[Assafl]

It would be nice if they stated what parts failed, the radiation exposure dose that these parts that failed had, and what protection did they use (lead box, etc.).

Indeed it would be nice to know what happened to those robots, but I wouldn't be too suprised if that knowledge is protected as a trade secrets. In that sense you are right, even disasters are a good business for some. That said, I haven't looked the subject and my tendency for pessimism cynicism might trick me here.

Good grief. Why cynicism???  Whenever there is something of this magnitude it is VERY hard to project just how much it will cost to handle it. Many times, when there is a flurry of non-scientific articles, and you look at the legislature (it would be the Diet in this case) - there may be discussions about further funding. Maybe Not.

Tokyo Electric cannot fund this - not entirely - it is vastly bigger dollars than what a utility is capable of handling. No cynicism. How much did Chernobyl cost? It doesn't become cheaper over time. Those idiots beaurocrats who let the people (and children) of Pripyat stay in place. How much did it cost to do the surgeries to get the 5000 or so thyroids out. And the medication for life.  Who do you think pays for this shit??? Not reactor unit 4. For sure.

[raspberrypi]

Radiation phobia is very prevalent, even among intelligent and educated people. Sad - just no perspective.

Nuclear power is our only out to the global warming epidemic right now. Nuclear can b safe just dont use water as a moderator or coolant. The only reason why we dont have NaK cooled or pebble reactors is because nixon favored the water cooled designs and not enough money was put into them. Coal power plants actually emit more radiation around the plant then nuclear ones. We worry about the waste as a 1000 year problem but we are now using the what was considered waste 50 years ago as fuel. Who knows what solutions we will come up with in the next 50 years. Even water cooled reactors are safe as long as they have reliable power source to cool long enough for a safe shut down.

[D_Money22]

I would actually follow up on that by taking it one step further, the current pressurized reactor designs are awful. Not only are they inefficient, when something goes wrong (as we have seen) your strating internal pressure is well over 100 atmospheres, plus any additional generated by the catastrophic failure of the reactor and uncontrolled fissioning and decay. I firmly believe nuclear is our best option (at least short term, with a case for long term) for combating climate change. However, I think a whole lot more thought needs to be put into designs including molten salt reactors, such as thorium reactors, as these designs hold incredible potential to solve many of the problems I previously identified.

[Assafl]

I would actually follow up on that by taking it one step further, the current pressurized reactor designs are awful. Not only are they inefficient, when something goes wrong (as we have seen) your strating internal pressure is well over 100 atmospheres, plus any additional generated by the catastrophic failure of the reactor and uncontrolled fissioning and decay. I firmly believe nuclear is our best option (at least short term, with a case for long term) for combating climate change. However, I think a whole lot more thought needs to be put into designs including molten salt reactors, such as thorium reactors, as these designs hold incredible potential to solve many of the problems I previously identified.

The concept of "putting more thought" doesn't really work in safety engineering. Sure - you put all the smarts together and figure out all the possible scenarios. But then come a black swan and whatever you prepared for is insufficient (inexperienced operator & crappy experiment; tsunami; earthquake; too much rain in a particular place in California; a hurricane; a faulty seal from Martin Marietta; or even a radioactive Russian satellite that falls on Canada). Sure - there were many ways that the Fukushima accident could have been averted. But just "putting it higher" - has its own drawbacks. Longer cables, perhaps more sensitivity to earthquakes etc.

I am pro nuclear but am severely jaded (my father has a PhD in nuclear safety engineering - so obviously my entire family thinks nuclear is a sound way forward with rising energy demands). But going headstrong into the causes and effects of these disasters is the only way to assuage concerns regarding safety. Just like the flight industry reacts quickly and resolutely to flight disasters (and near accidents) - correcting systems and procedures that result in safety risks.

Perception is a problem. Lead poisoning is scary - but it was not when the big oil companies stood against unleaded fuels. Chemical pollution is also horrible - yet people are fine with having a stack near their house. But genetically modified foods - or radiation? Many go gaga. But then again, I am sure there are Italians living on the slopes of mount Vesuvius who are terrified of pressure cookers. Go figure..   

[wraper]

Okay - I follow that the gray unit is better as an SI unit. my point was the use of Sieverts with a robot.

So should they sent some human there to measure in Sieverts?

[Assafl]

Should they send humans in there? No. At least I wouldn't go in there.

But this thread (and the articles discussed) are not about the risk of radiation to humans. It is about the risk of radiation to robots. I cannot think of an equivalency of dose applicable to flesh and organs applying to a radiation hardened CPU. That is usually in rad or as you pointed out gray.

I would have preferred that the article would be more scientific. Stuff that starts with "1 is a lot - it is what NASA allows astronauts over their entire life" and then goes to show the robots die as well - what is it really about? Why are they posting this? Is it funding? Is it blaming Toshiba for bad engineering? Is it to scare people that large doses of radiation is bad? Duh.

So radiation kills electronics. Wow. Maybe it is news to you. Good. Maybe that is why the high powered RTG are always spaced many feet from the electronics they power - from satellites to moon surface devices. Except in pacemakers. But those are actually pretty low power.

[wraper]

So radiation kills electronics. Wow. Maybe it is news to you. Good.

During conversation it sounded like it was news to you. It was you that claimed that robots fail not due to radiation but conspiracy:

Instead of Sieverts, the problem at stake may be in Yen. Tepco might just want more money.

Should they send humans in there? No. At least I wouldn't go in there.

But this thread (and the articles discussed) are not about the risk of radiation to humans.

C'mon, do Tepco or whoever care about this tread and what we are discussing to start measuring in different units? Did they send those robots for the sake to test their rad hardness? Or to estimate danger for humans, as I say it again.

[Seekonk]

If we just sterilized a lot of people, world problems would go away.  What happened to ZPG.

[cdev]

The biggest problem with fission reactors is the spent fuel remains "hot" and problematic for thousands of years, presenting a huge storage problem which the owners of these plants often attempt to make society eat the cost of. It has to be cooled, continuously cooled by one means or another. That's why I think we should not build any more nuclear fission reactors until we've got a more responsible world with better technology to safely dispose of the nuclear waste. Corporations are often completely irresponsible and incapable of managing such materials safely long term.

Right now these spent fuel ponds all around the world are each a disaster waiting to happen.

[SeanB]

Spent fuel is not really a problem. Remember that all the uranoim mined in the world is basically a recovered material from natural reactors, that operated for millenia, were in water soaked silts and muds, and where the remains are still contained there 450 million years later.

The deposits were made by erosion of volcanic rock which has Uranium group metals in it that were oxidised by the atmosphere as the rock eroded, and were washed down rivers to be separated naturally by mass into pockets of heavy minerals, and which were in turn covered with mud and silt till there was enough for a water moderated natural reactor ( higher concentration of heavy nucleotides then to start the reaction going) to start up and run for long enough to boil off the water, cool down and get wet again and repeat the cycle. This went on for a long time till the most active materials were exhausted, and the by products stayed in the same locations for the 450 million years, sitting in sandstone with water flowing through, till they were mined for the current power plant uses.

So choose, low level waste mildly radioactive for long periods, like living in Edinburgh on top of a massive block of radioactive basalt and granite, exactly like people love as a kitchen cutting surface and as a counter top all round the room, with some high level waste that will decay in a century to pretty much the same. Or live with a coal plant putting 100 times as much out into the air you breath, or a gas powered plant doing the same with Radon gas, or with solar panels made with toxic elements in them.

The reactors were in Gabon, at a little place called Oklo, and are a source of a lot of materials along with uranium.

[mtdoc]

As cdev points out spent nuclear fuel remains a problem for thousands of years. And no it is not analagous to low level naturally occurring radiation:

Spent nuclear fuel is highly radioactive and potentially very harmful. Standing near unshielded spent fuel could be fatal due to the high radiation levels. Ten years after removal of spent fuel from a reactor, the radiation dose 1 meter away from a typical spent fuel assembly exceeds 20,000 rems per hour. A dose of 5,000 rems would be expected to cause immediate incapacitation and death within one week.
Some of the radioactive elements in spent fuel have short half-lives (for example, iodine-131 has an 8-day half-life) and therefore their radioactivity decreases rapidly. However, many of the radioactive elements in spent fuel have long half-lives. For example, plutonium-239 has a half-life of 24,000 years, and plutonium-240 has a half-life of 6,800 years. Because it contains these long half-lived radioactive elements, spent fuel must be isolated and controlled for thousands of years. A second hazard of spent fuel, in addition to high radiation levels, is the extremely remote possibility of an accidental “criticality,” or self-sustained fissioning and splitting of the atoms of uranium and plutonium.

In addition - spent fuel rods initially require active cooling for several years or risk igniting of the zirconium cladding which could result in massive atmospheric spread of dangerous radiation. One major, extended, and widespread electrical grid outage and that danger becomes real.

In general humans just cannot adequately deal with risks on a very long time frame.  We have a hard time comprehending risks beyond the short term - our brains are not wired for it. Immediate dangers activate our limbic system and motivate us to act quickly. Medium term dangers (up to a few years out) can motivate us adequately (via the neocortex) - since our evolutionary history included events which left those who did not react to such potential threats (decline of local food resources, etc) behind.

But we just cannot as a species deal with such long term risks - risks that extend far beyond the length of even the most long lasting of past human civilizations.

I think the fact that otherwise well informed, technically savvy members of this forum can say things like "spent fuel is not really a problem" demonstrates that.

[james_s]

It has always seemed to me that if the spent fuel is that active still, there ought to be much more energy that can be extracted from it. Surely if it has to be actively cooled we can use that thermal energy for something useful?

[SeanB]

Exactly, but there is no political will to reprocess that to blend with virgin fuel and use it again, so it sits there boiling water in a pond for decades, instead of making useful steam to generate power.

[james_s]

Exactly, but there is no political will to reprocess that to blend with virgin fuel and use it again, so it sits there boiling water in a pond for decades, instead of making useful steam to generate power.

A lump of it in a lead vault in my back yard could heat my house for free for the rest of my life. Obvious logistical problems there, but I'm sure there are larger scale operations where something like that could make sense.

[BrianHG]

Cant wait for cheap fusion power, though once we have it, I'm sure there will be reasons it wont be cheap for the regular end consumers...