Fukushima: Removing Spent Fuel Rods

If you’ve ever looked at Fairewinds Associates videos, you know that the big problem at Fukushima is the drying up of the cooling pools which are suspended over the reactor vessel and contain the spent (but extremely radioactive) fuel rods.

Before a worst case accident occurs, I believe the spent fuel rods must ultimately be removed from the damaged cooling pools and stored off-site (that is, in a place that doesn’t happen to be over a nuclear reactor).

But how do we get the rods out of the cooling pools? The tower crane that I found in Google Sketchup 3D Warehouse is only 60 meters tall, which is unfortunate because that’s about the height of the Fukushima reactor buildings (prior to having their roofs blown off) and therefore doesn’t allow any reach.

So I added a base of shipping containers like so:

The crane on the ground erects the platform, upon which is built the upper crane, which can access the fuel rods in the cooling pool and remove them.

Shipping containers are normally stacked no more than seven or eight high, but since an intermodal shipping container can hold about five times its weight, I thought it was fair to assume that empty containers can be stacked up to five times higher than loaded ones. If so, then a stack of twelve as shown is not a problem.

I’m not saying there aren’t better ideas. But I do think this is safer than concrete burial.

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Japan’s Choice: Go Solar or Go Dark

Japan’s dim capital faces further power crunch” (Associated Press, April 3):

About 9 million kilowatts of capacity may be gone forever as the radiation-leaking Fukushima Dai-ichi nuclear plant is likely to be scrapped and the future of the halted Dai-ni plant is uncertain. That suggests chronic shortages until new power plants are built. A government plan for the power supply that may include new plant construction is to be announced at the end of April.

Electrical power is critical to the automobile and steel industries, and one Tokyo resident comments, “I think it will be nearly impossible for Japanese people to live without air conditioning.”

It will take at least ten years to construct a nuclear power plant. Waiting that long is out of the question. So does Japan go for fossil fuel? That’s not so cheap either.

For fossil fuel plants, according to wikipedia, “Construction costs, as of 2004, run to US$1,300 per kilowatt.” But Synapse Energy comments:

Construction cost estimates for new coal-fired power plants are very uncertain and have increased significantly in recent years. The industry is using terms like “soaring,” “skyrocketing,” and “staggering” to describe the cost increases being experienced by coal plant construction projects. In fact, the estimated costs of building new coal plants have reached $3,500 per kW, without financing costs, and are still expected to increase further.

For the replacement of 10 gigawatts of electrical capacity, Japan would need to spend $35 billion on coal plant construction. Remember, that’s just on plant construction. Then you have to buy the fuel.

Coal-generated electrical power operational costs are 5.5 cents per kilowatt hour. Even at half capacity of 5GW, that would be $24 billion added to the cost over the next ten years.

Total coal power cost for Japan: $59 billion, and it will take several years to build the plants.

Fortunately, there is a power source that Japan can build now — and will provide power cheap. It’s solar power. Current costs for rooftop solar photovoltaic installations even in the anti-solar US have dropped to $4.22 a watt — or $4220 per kilowatt.

For the 10 GW that Japan needs, the total solar power cost would be $42 billion, versus $59 billion for coal power — and, perhaps, Near Infinite for nuclear power.

The aforementioned price for community PV installations is without tax incentives or subsidies. This can be done personally, without a massive government program.

Indeed, the only thing that may prevent Japan from going massively solar this summer is the government, which will dangle false promises of a future glut of subsidized fossil fuel power in front of consumers in order to deter individualized solar power installation in the near term.

But can the solar power industry meet the need in the short term? Solar power industry inventory is currently 3 GW. That’s thirty percent of Japan’s power production gap, already built and ready to install.

Sweat out the long hot summers and shiver through the long cold winters in the dark waiting for fossil fuel plants to be built, or go solar now. That’s the choice for every Japanese citizen, community, and company.

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Robots and Radiation

Robots to the Rescue,” Technology Review (29 March 2011):

. . . . constructing robots designed to withstand high levels of radiation would be difficult. “For radiated environments, one needs robots that are particularly rugged,” he says. “Such robots typically are rather large, slow, have only a few CPUs and sensors.”

Surely the slowness issue doesn’t apply to teleoperated robots. Commands sent through a fiber optics cable travel at the speed of light, no matter what the exterior radiation level is. And so what if the CPU manipulates the claw in milliseconds rather than microseconds? That’s still too fast for a human operator to notice.

Radiation also has relatively little effect on bulk electronics like batteries, power supplies, servo motors, etc. A radiation environment high enough to affect a 24 DC motor is barely this side of a nuclear bomb detonation.

We don’t have to shield an entire robot. Just the vulnerable microelectronic circuitry that forms the “brains” and sensors.

I find it hard to believe that even the microelectronics would be more vulnerable to radiation than humans are. After all, the debate about whether cell phone radiation affects human brain tissue is in the news all the time, but we seldom if ever hear any concern over whether the same radiation affects the cell phone itself.

Even if the radiation in a damaged nuclear plant is sufficient to damage electronics, wouldn’t it be better to simply replace a burn-out module in a robot, on-site, rather than having to hospitalize a human worker due to overexposure?

As I recall from my brief, unhappy days in nuclear power, radiation is attenuated by a factor of ten by a two-inch thickness of lead. It’s got to be a lot easier to encase electronic components in a lead box than to shield an entire human body.

Even cameras could be protected, by using periscope configurations. The camera would be placed in a thick, shielded box with mirrors:

Then a tube is mounted atop the box with mechanisms to tilt and turn the upper mirror:

And in turn the periscope assembly is mounted on the robot:

Now, judging from this illustration, I can see that I need to rescale my robot, because video cameras are much smaller than I’ve been showing. That in turn would minimize the size of the protective lead box.

But would the lead box still have to be so heavy that the robot couldn’t move? Many hobbyist robots these days are powered by wheelchair motors, which can carry a hundred kilograms or more. A small lead lined box two inches thick would weigh less than this. Even four inches is possible, and that would attenuate radiation by a factor of a hundred.

Anyhow, how much radiation are we talking about before conventional electronics breaks down? I came across this statement at eHow.com: “Ionization on electronics from nuclear radiation can damage semiconductors within devices for long periods of time after only 5,000 rads of radiation.” ‘Only?’ That dose is five times more than is needed to kill a human worker in a day.

I hope someone reading this will send me a link to numerically-specific (as opposed to general-concept) information on how much radiation it takes to kill electronics.

But until then, I remain convinced that conventional electronics can fare better against radiation than can human beings. Therefore, as much as possible, teleoperated robots should replace human presence in high radiation environments.

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Robot door-opening tool

“Robots to the Rescue” (Technology Review, March 29, 2011):

Some experts also question how helpful robots would be after a nuclear plant disaster. Something as simple as a locked door could prevent a robot from doing its job.

Is it really that hard for a robot to open a door? I came up with this design for a robotic door opening tool:

It’s carried in a wagon behind the robot, then lifted and oriented like so:

It would be under remote control, of course, relayed by the robot to the human operator. I’m debating whether the mode of communication between the robot and the door opener would be radio, infrared, or cable. I’m leaning toward infrared.

But what if the door is locked? Hmm . . . have to design device to insert and turn keys. But is that impossible? It seems to me that these days, journalists can write anything about, say, time travel, and everybody nods. But suggest the ability of a robot to insert a key into a keyhole — why, that’s sheer fantasy!

The above article, incidently, continuously hammers the point that you need extreme radiation hardening for robot sensors to function in a high-radiation environment. I have my suspicions that the problem is exaggerated, but that’s deserving of another blog entry.

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TOR Systems List

This picture identifies the major systems for the TOR. (TOR stands for Tele-Operated Robot.) Here is a preliminary parts list.

1. Arduino Microcontroller for input/output interface between communications and motor/servos. Easy to find, only $35.

2. Wireless Camera available on Amazon.com for under $100.

3. Servos/Actuators can be found at digikey, etc.

4. Sheet metal enclosure. I’m not sure where you get the material, but it must be available locally because it’s used in machine shops all over the place. There are books on Amazon about how to use it.

5. Motor (Wheelchair) is available on eBay for around $100-$200. Behold:

6. XBee for point-to-point radio communications. Another $30-$40 item, available at Maker Shed and elsewhere.

Lots of things left off this list: like front tires, 12 V batteries, battery connector, electronics mount and shielding, all kinds of stuff. But this list is a start toward the process of actually building the robot.

And the components connect just like lego bricks, so all you have to do is buy them and snap them together . . . riiiiight. But seriously, I think the hardest part of this project will be to clear enough room in my apartment to build it.

Well, I suppose the arm is going to be a challenge too. On the other hand (excuse the appendage-related pun), if you’ve programmed one servo, you’ve programmed them all. Right? Riiiiight.

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Robot arm studies

As I get closer to designing a teleoperated robot that I can actually build, I wanted to experiment with different robot arm designs. Hence I took the re-design of a couple days ago and made several re-designs out of it in turn.

In this first version, I deleted the camera at the base because the robot already has a camera. I also changed the claw servo from radial to linear. I’m not sure that was such a good idea, but there we go.

Here I got rid of the back-arm and compensated by extending the fore-arm. I might need a counterbalance now for the fore-arm.

Always vigilant to cut out costly servos, I eliminated the ability of the wrist to turn clockwise/counter-closewise. The claws can still tilt and pick up stuff and punch buttons. Maybe it’s not so good at pulling throttles.

Doing away with one more servo. I tilted the claws as a compromise angle because the wrist angle is now fixed. (My attempt to make the claws stand out more with different coloring seems to have backfired.)

Here’s an unconventional variation. No radial servos, just linears — and only three are required, though the design looks complicated at first sight.

Here is a second view, from underneath. Think of the silver bars as sliding along the black slots, and you can see how this works in three dimensions. I don’t think I’ll ever build this one, however, now that I see how it looks. But that’s the beauty of Sketchup.

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Robot re-design

The elbows-back manipulator arms of the previous version always make me think of Fozzie Bear going, “Waka waka!” The design was taken from a space robot and doesn’t really work on a ground vehicle, so I replaced it with the new manipulator.

The redesigned robot looks much more plausible in the control room:

So why are humans still being dangerously irradiated in the control room, when teleoperated robots can monitor gages and push buttons?

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Japan Solar Energy Graphics

Sometimes it seems that nuclear power advocates are attempting to insinuate that Japan doesn’t have enough land area to use solar energy in place of nuclear energy. Here’s what the solar panel requirements actually look like.

Per person:

[Calculations: Electrical consumption per person is 8507 kwh per year. Daily consumption is 8507/365 = 23.3 kwh. Insolation at Tokyo is 4 kwh/day per square meter. PV panel efficiency is 15 percent. Panels per person = (daily consumption)/(insolation * efficiency) = 23.3/(4 * .15) = 40 sq. meters]

Here’s the graphic for all Japan:

[Calculations: Area per person = 40 sq meters. Population of Japan = 127 million. Total Area = (Area per person) * (Population of Japan)
= 40 x 127 million = 5080 square kilometers]

I don’t think it would be that difficult for the Japanese to dedicate this much land area to solar panels. Take the roofs of buildings and homes, then over roads and streets, and that should handle most of it.

At any rate, the required surface area is less than 1.4% of the total land area of Japan, and the extra crowding would certainly be less discomforting than the extra radioactivity they’re now experiencing.

(The radiation symbol is drawn to scale to cover the exclusion zone around Fukushima Nuclear Power Plant #1.)

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Robot Arm in Sketchup

This design is based on the first iRobot photo shown here. Sketchup, by the way, is not for CAD, it’s for quickly illustrating concepts.

Sketchup can draw smooth curves as in the iRobot photo, but boxes are of course faster to draw, and also if I were to actually build this as an amateur, I would be using boxlike enclosures (rather than aesthetically-pleasing curves) to save on manufacturing costs. It would simply be a matter of cutting and welding sheet metal, which I figure I could learn how to do in less than a week.

Here is the video camera. Note that the gray cylinder connectors rotate, which means that the camera box can be tilted up and down. The lower cylinder enables the entire mechanism to twist right and left, and the one on the right, of course, tilts the arm up and down.

In this overhead view, we see that the cylinder on the left enables the forearm to be twisted independent of the base. This enables the arm to extend and contract its reach.

A detail of the ‘claw’ or ‘hand.’ According to the article, the iRobot is capable of lifting over two hundred pounds, which I find amazing because it doesn’t look that sturdy. If I can build an arm that can lift fifty pounds, I will be happy!

Let’s step back and again look at the side view, which suggests how easy it would be to put this on my existing robot design.

By the way, I note that one of the commenters on the aforelinked news article claimed that teleoperated robots aren’t really robots because they aren’t capable of independent action. I’m becoming aware that this is a matter of confusion with a large audience, so perhaps in the future the distinguishing term for this kind of teleoperated robot should be ‘telebot’ or ‘telbot.’ Unfortunately, if I were to use such a term now, the average person would go, “Say what?” So maybe I should stick with ‘teleoperated robot,’ but I suppose even that term is going to get puzzled stares.

I count seven cylinders in all, which is a number low enough that it can be handled by one Arduino. I guess I should read up on servos now.

Another thing I should do is learn how to do Sketchy Physics. Then I could really show off the articulation. Ah, so much to do, and so few brain cells to do it with!

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Edison and His Inventions (an 1894 book review)

While prowling in the local Half Price Books, I came across this book. This is not a reproduction of an 1894 book, it is an original, and it only cost me $25. I feel pleased.

Here’s the title page, which gives you a taste of what it’s all about:

At the time of publication, Edison was still in his mid-forties, and the War of the Currents had been waged at the Chicago Colombian Exhibition the previous year. But you won’t find elaboration of Tesla here. This is a literary ode to Edison.

Edison, it seems, was quite the scamp as a child. He was always experimenting with things and causing mayhem with fires, explosions, etc. This did not ingratiate him with others, as we can see from these illustrations:

Well, at least the cat didn’t push him around. In any case, lest you think Edison was a juvenile delinquent, there is this charming tableau:

Okay, so what did Edison invent — I mean, besides crazy stories about his childhood?

Well, he is credited with inventing the electric light, but as we all know by now, he was more an innovator in that. Still, the book recounts an impressive list: the New Edison Dynamo, the Pyro-Magnetic Dynamo, Train Telegraph, the Mimeograph, Etheric Force (“a new discovery”), Tasimeter, Harmonic Engine, Multiplying Copying Ink, and of course, The Sonorous Voltameter.

You know, there are times when I wondered if the author was making some of this stuff up. But at least with the saner stuff, there are schematics:

This is for the ‘quadruplex,’ which apparently allowed four telegraph messages to be sent at the same time on the same wire. Big deal a hundred and twenty or so years ago, but not so much in use now that even Third World countries have cell phone networks.

The biggest deal of all back then was the phonograph, and you can tell just how big it is by looking at the expression of this devotee:

Well, I think she’s enamored of the phonograph. Are those poppies on the table?

This book gets so random sometimes. There’s a long section on jokes about the phonograph and the telephone, and some embarrassing jokes in ethnic dialect. I wouldn’t precisely call it racist, but it’s . . . embarrassing.

Anyhow, here’s the Electric Pen:

I never saw one of these while growing up. Just about everything Edison invented has become obsolete by now, and this was one of the earliest victims of the march of progress. Still, it looks kind of cool. The sort of thing that Make would have an article about.

Here’s a little flavor of how the focus of technological innovation in the nineteenth century differs from that in the twenty-first:

The clearness of the phonograph’s articulation, Mr. Edison says, depends considerable upon the size and shape of the opening in the mouthpiece. When words are spoken against the whole diaphragm, the hissing sounds, as in shall, fleece, etc., are lost. These sounds are rendered clearly, when the hole is small and provided with sharp edges, or when made in the form of a slot surrounded by artificial teeth.

I’m sure engineers at Apple encountered similar technical issues for the iPhone.

Now here’s the schematic for the electric light:

Notice, there’s nothing on the schematic about “Japanese Bamboo” for the filament, which modern technology historians identify as the real breakthrough which established Edison’s claim to fame for ‘inventing’ the electric light. Prior to JB, filaments burned out in a few hours, rendering electric lights as laboratory toys. After JB, filaments lasted for many days and electric lights spanned the continents.

The fun stuff in this book are the more obscure inventions, like the micro-tasimeter, which Edison invented to measure the temperature of stars. Did you know Edison was into astronomy? Quite a few pages in this book cover it, so evidently he was a proud father of this invention:

As you might have guessed by now, what I like most about the book are the illustrations. And not so much of the inventions as the glimpses it provides of A Lost Time. For example, here is a dynamo room, perhaps not so different than dynamo rooms today but consider that this was so novel back then that it appeared in a book aimed toward a popular audience:

Some of the shapes of this technology haven’t changed in a century — note the conduits on the ceiling — but obviously the proportions of the machinery have changed a great deal since Edison’s time.

The decision to include some illustrations in the book reveal far more about the intended reading audience than Edison. For example, the author thought that people would be interested in seeing illustrations of Edison’s buildings, like so:

This picture reminds me of a Mystery Science 3000 episode, where Joel and the robots are watching a movie from the 1930s and there’s a scene in a stadium, and Tom Servo says, “Everyone in this scene is dead.” Yep. The little boy grew up, and now even his grandchildren are probably dead. I wonder where the dog went, or if it even existed other than in the illustrator’s mind as a counterpoint to the magnificence of the Edisonian edifice. Was this illustration based on a photograph or camera obscura? No matter, Edison’s legacy looms over all, saying, “You have been lost to oblivion, but I shall endure.”

Well, for a while longer, perhaps. But then there’s this scene, in which a passenger aboard a train engages an Edison invention to telegraph while in transit:

To be sure, a valuable innovation in its time, but not much use for it anymore — nor for the Edisonian process of reproducing sound waves by scratching vinyl. It serves as a reminder of the transitory nature of engineering glory.

Could the day come when Edison is forgotten? Maybe he should have spent a little time talking about death rays and communicating with Martians. That seems to have secured immortality for Tesla.

Tesla has also gained a lot of street cred in the anti-patent community, which is odd, because I don’t think Tesla ever spoke against patents. On the other hand, this book concludes with Edison’s anti-patent remarks: “I have become extremely skeptical as to the value of any patent, and so long as our patent law remains in its present iniquitous shape, I shall try to do without patents.”

And then he really lets loose:

The present law is a constant temptation to rascals, and virtually offers a premium on rascality. Under it the infringer of a patent is not interfered with until the real owner can show that he has the monopoly of the device in question. The process may take years, during which the infringer, who has money and audacity enough to secure another man’s invention, can go on and perhaps wear the rightful owner’s life out by litigation and annoyance.

Indeed, Wilbur Wright is thought to have died prematurely in part because of the stress of patent fights over the invention of the airplane. But as for Edison, I suspect that the historical record is that he did not keep his resolve and there were many more patents to come in the decades he had yet to live.

Anyhow, this book is an interesting glimpse of a technological lost world of electric dynamos carried in horse-drawn carriages, of carbon diaphragms being state of the art, of sonorous voltameters, and incredulity that machines could reproduce voices and send them anywhere at the speed of light.

Which, when I think about it, is pretty incredible. Given that we take it all for granted now and have lost our sense of wonder, perhaps we deserve to have lost the secret of how to directly convert burning coal into electricity:

Well, to tell you the truth, there are some passages in this book that made me wonder whether the author wasn’t quite accurate in taking notes when he interviewed Edison, or maybe he didn’t interview Edison at all and just cobbled this book together from unattributed newspaper clippings from reporters who did talk to Edison but still weren’t quite accurate in taking notes — and may have committed a little ‘inventing’ of their own along the way.

But what the transcriptions indicate that I do find it credible is that for all his electrical inventions, Edison really had less of an understanding of the nature of electricity than the typical high school student today. Perhaps that’s why reading some of the ‘explanations’ of how his inventions work tend to be less than enlightening. And once again, I am confounded with just how far a person can go while having only the sketchiest idea of where he is going.

Anyhow, there’s a scanned version of this book on Amazon and at the time of this writing there is also a first edition (1879) available on eBay, where it’s bidding $124 at the moment — which kind of makes me wish I hadn’t crumbled so many pages while reading mine. But I doubt that my 1894 edition would command as much. Besides, it’s not for sale. I need it for guidance.

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