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  Cherohula Skyway Closed by Mud Slide

Up here in the Tellico Mountains, we’ve been busy building Arks. Over the 3rd week of January we got a total of about 8 inches of rain plus a little snow! That replenished the badly needed ground water and brought the Tellico Rivery back up to snuff but it also had some bad effects.

One effect is a mud slide that closed the Cherohula Skyway at about the TN/NC line. The Skyway is a destination for those who like to ride sport bikes, drive sports cars or just see some beautiful scenery. It connects Tellico Plains, TN with Robbinsville,NC.

On about the 17th of January, a huge mud slide took out a good hunk of the roadway and resulted in Tn-DOT closing the road completely. The next day my friend and neighbor Vicki J and another friend Tracy drove up to look at and photograph the damage. Here are Vicki’s photos.

The damage is extensive enough that the road will probably be closed through at least most of the summer riding season. No word yet from TN-DOT about a time to repair.

John

02/03/2013 update:  With speed that I didn’t know a government agency could pull off, TN/NC-DOT has the Skyway back open. I haven’t driven up to see what they’ve done but I’ve heard that they removed the guard rail on the other side and made a lane out of the shoulder. In any event, it’s back open and all is well.

  Shop Lighting Done Right!

Hi, my name is John DeArmond and I’m a flashahaulic. Or lightahaulic. Or something like that because I’m attracted like a moth to things that give off light, especially lots of light.

Recently I decided to solve a problem that has been getting worse with diabetes and age – the ability to resolve fine detail. The eye doc hasn’t been much help but light and lots of it has. Just like with a camera, if you stop down the iris, your depth-of-field deepens. It takes a lot of light to stop down the human eye which has evolved to handle bright daylight. So I decided to create bright daylight in my shop using BACFLs (big-assed Compact Fluorescent Lamps)

Here’s the result.

A marvelous thing happened. I can now see!!!

I need to mention BuyLighting. They’re my go-to source for oddball stuff such as these BACFLs. I recently placed an order for the lamps for this project. One came in damaged. A crack in the glass let the air in. Its filaments flared for a moment and then poof! No light.

I dropped customer service a note about the problem. The nice lady on the other end promptly sent me a replacement and didn’t ask for the old one back. THAT is customer service. Keeping the old lamp is going to let me do a future article dissecting one of these large lamps to show how it works.

Enjoy

John

  Anatomy of a Bogus Headline

For a few days the headlines about Fukushima screamed that Unit 2 and Unit 4′s spent fuel pit “reignited” their nuclear reactions long after March 11th. As a nuke, these kinds of headlines make me cringe with disgust because they’re almost always false. The problem is that there is rarely enough original source information to analyze what is claimed. This instance is different.

The particular headline that a reader brought to my attention is here. After the sheer audacity of the headlines, the next thing that catches one’s attention is that the article is hosted by MIT. That should give it some creds, right? Didn’t work this time. Fortunately the writer cites his source, a paper by a Japanese professor named Tetsuo Matsui. His paper is here.

The Basis for the Claim

Two of the major fission products (the results of the uranium atoms splitting) are Cs-137 and I-131. The fractions of these two isotopes, that is the percentage of fissions that produce them are very well known. fI = 2.88 × 10-2 and fCs = 6.22 × 10-2 for the
cumulative thermal fission yields of U-235, taken from the IAEA data base.

I-131 has about an 8 day half-life so after the reactor has run at a certain power for at least 8 days, the amount of I that is produced equals the amount that decays. This is called secular equilibrium. On the other hand, Cs-137 with its approx 30 year half life continues to build in concentration for the length of time the fuel is in the reactor.

With a little fancy math detailed in the paper, one can compute the amount of I and Cs at the point of shutdown, what he calls point X, to a fair degree of accuracy. After point X, the ratio of I to Cs should decline at a fixed rate set by I-131′s 8 day half-life. Using data supplied by TEPCO he plots that ratio on a semi-log chart called Figure 1 in his paper and reproduced here. The red arrows and numbers are my addition.

Several things I don’t like about this plot. First, the data is noisy. the log scale compresses the noise toward the upper left but even then there is a huge outliers at “1″ and another at “2″. I don’t like to see data systematically deviate from the norm as it does at “3″. That those points align with a much different slope than the rest alerts me to possible systematic measurement errors.

This is the first problem – unreliable data. Especially in the days immediately following March 11, the radio-chemlab must have been in a mighty struggle to handle the volume of samples to be counted and to devise ways of counting the extremely hot samples that were coming in. Preventing the hot samples from interfering with the measurement of lower level samples is another problem. This data is OK for its intended purpose – to show the extent of contamination at various points but it is too noisy to base such a controversial conclusion on.

This is the data that he bases his conclusion on, Figure 2 in the paper. In particular the grey dots above the red line. They represent samples taken from the drain sump of Unit 2. The unit 4 data are the pink dots which are all over the place and are worthless in this evaluation.

Occam’s Razor

The principle of Occam’s Razor is that the simplest explanation that fits all the data is usually the correct one. Our good professor failed to apply that principle in several instances. First a critical assumption:

“If there is no strong chemical filtering effect in draining contaminated water from the reactor buildings, it would be difficult to understand the observed anomaly near the unit-2 reactor without assuming that a significant amount of fission products were produced at least 10 – 15 days after X-day.”

The problem with this assumption is that we know from TMI-2 that concrete has a strong preferential absorption for Cs over I. Further, we don’t know what compound form the Cs and I are in. Some will, of course be cesium iodide. But Cs is a very reactive element and would combine with other elements present in the water. Some of those elements include salt from the seawater. Cs would displace the Na in salt to form cesium chloride. That would attack the concrete and from an insoluble sludge. Thus with just a little mental exercise, one can think of several plausible “strong chemical filtering effects” that would preferentially reduce the Cs in the drain contents.

There are many other questions that arise simply because the professor failed at one of the most basic principles of science – be skeptical. Be skeptical of the data until proven valid and be skeptical of the results until validated by using a different method.

One such different method that could easily have been done would have been to calculate the number of fissions necessary to make the amount of excess iodine that he thinks he saw. I’m not going to try to compute that value for this blog post (I’d probably make a math mistake!) but I’d guess that the number of fissions would be in the 10E17 to 10E20 range.

That would not be a quiet reaction. Immense energy would be liberated causing violent boiling around the critical mass. The boiling would displace the water moderator with steam which would shut down the reaction. This process would repeat indefinitely until and unless the mass broke itself apart. The pulsations caused by the steam bubbles forming and collapsing would certainly have been audible outside the reactor building and a plume of steam would erupt.

Depending on how intense the fission reaction might be, this pulsating reaction might go on for days or even become a continuing process. Certainly not something that would go un-noticed.

In any event, doing the number of fissions calculation would have been a great cross-check on his I/Cs ratio calculation. Unfortunately he didn’t do that.

Let’s consider another faulty assumption – that the fission took place only in U-235. The fuel is primarily U-238, enriched from 2 to 3% with U-235. It is the U-235 that fissions with slow or thermal neutrons. Neutrons emitted from a fission are fast. They must be slowed before the U-235 reaction can take place. In this type of reactor, the cooling water performs this moderation. Remove the water and the reaction stops.

As the reactor operates some of the fast neutrons are absorbed by the U-238 and after a short decay chain become Pu-239. Pu-239 in turn can absorb a neutron and become Pu-240. Both isotopes are thermally fissionable. That is, they fission when a slow neutron strikes the nucleus. As the reactor runs, the concentration of Pu builds until at the point the fuel is ready to be removed during a refueling outage in excess of half the energy produced is from fissioning Pu.

The fraction of I and Cs produced from Pu is different than that produced by U-235. Therefore the assumption of only U-235 fission is incorrect. Unit 2′s core was an old core so many of the fissions would have been from other than U-235.

Another thing to consider is the lack of other fission products detected. A reaction large enough to make that much iodine would also make a large quantity of radioactive noble gases. None were detected. If you look here you will see that the site is ringed with area radiation monitors. The readings for each day since the event are there for the downloading and study. I went back and looked at the data around the time period claimed for the criticality event and saw nothing other than the slow decay of fission products released by the initial event. This right here is a big nail in the coffin of the idea of a spontaneous criticality event.

Improbability of Spontaneous Fissions

This is the real biggie. A reactor designed in the free world is designed such that the nuclear reaction will only take place under precise conditions. The fuel rod spacing has to be just right. The water moderator has to be present. And of course, the control rods have to be withdrawn. Most nuclear engineers, at least the ones I’ve talked to, consider spontaneous criticality in a damaged core to be a very unlikely event. Almost impossible. Let’s look at some reasons.

• As the center of the core melted, it made a mass of fuel pellets partially cemented together with molten fuel and control rods. The control rods in this type of plant contain boron carbide in powder form inside stainless steel tubes. These rods were fully inserted from the initial scram and so would be intimately mixed with the fuel. In the portions of the core where the temperature was great enough to melt the ceramic uranium oxide, it was also hot enough to melt the stainless steel control rods. Thus neutron absorbing boron carbide powder. The melting point of Boron carbide is higher than that of uranium oxide so it would be deposited as a powder throughout the “rubble bed” of fuel debris. This alone is enough to prevent criticality.
• The molten and partially molten fuel forms a dense, though somewhat porous mass. This displaces most of the water that is necessary for the pile to sustain criticality. No water, no criticality.
• There is evidence that the cores of all three reactors remained dry for several days after the earthquake. Again, no water, no criticality.
• TEPCO personnel were adding neutron absorbing boron in the form of boric acid to the water being injected into the reactors. So when the cooling water finally reached the damaged cores, it contained sufficient boron to prevent criticality.
• As I mentioned above, there was no detection of any other fission products above the quantities expected from the initial event.

Conclusion

No evidence other than that the one calculation made by the professor points to any possibility of a criticality event. The professor, probably wanting another publication for his resume, “pencil whipped” a few numbers, concluded that they looked OK and put the paper out there. But instead of sending it through the normal peer-review channels, he made it available to the media. Shades of Fleischmann and Pons of cold fusion infamy.

Until some other evidence of a criticality excursion presents itself – and none has to my knowledge – one must come to the conclusion that the professor is simply wrong in his conclusions.

  Fukushima Update 05/05/2011

Another Nail in the Coffin

of the Linear-No-Threshold (LNT) theory of radiation effects. A friend sent me this absolutely juicy article in which the author uses the Union of Concerned Scientists (LNT is their only reason for existence) cancer estimates against them. Here is the article.

In a nutshell, they applied the USC’s “any radiation causes cancer” methodology to airline flight where the population acquires thousands of man-REM of exposure over terrestrial background by virtue of being closer to outer space. In particular he looks at airline workers (stewardesses, pilots, etc.) According to the LNT cra… er theory, they should be dropping like flies from cancer caused by the “excess exposure”.

Fukushima Activities

The most notable news today is that two workers entered the Unit 1 reactor building for the first time since the explosion. They took radiation readings and prepared for the installation of air clean-up units pictured at left. Each unit contains a charcoal bed for iodine removal and a HEPA (High Efficiency PArticulate) filter to remove fine dust. The idea is to operate these units for several days to reduce the amount of airborne radioactive material inside the plant.

The goal of this activity is to make the reactor building habitable long enough that workers can attach the necessary piping to set up a closed loop cooling system. Right now they’re operating on the “feed and bleed” system where fresh water is pumped into the reactor and then allowed to bleed out. That’s where the massive amount of contaminated water in the turbine buildings is coming from. The closed loop cooling system will recirculate the same water over and over.

Bracing the Unit 4 Fuel Pit

TEPCO is looking at the feasibility of installing a concrete and steel support under the #4 spent fuel pit to help support the earthquake-damaged pit. There is some valid concern that another strong shake could cause the pit further damage, perhaps cracking it so that could not hold water.

The image at left shows a small portion of the fuel pit taken on 04/28. One can see debris from the explosion laying on top of the fuel racks. No gross damage to the fuel is visible in this shot. This indicates to me that the fuel got hot enough to fail the cladding but not hot enough to melt. That there was a hydrogen explosion indicates that a large zircalloy/water reaction took place.

Exposure Data

MEXT (Ministry of Education, Culture, Sports, Science and Technology) has released a massive amount of data concerning environmental radiation in the exclusion zone. This is a truly gargantuan amount of data. It would probably take a month to go through all if it. I’ve sampled some of it. It supports what I said earlier, that with the exception of a few small places such as Iitate, there is absolutely no reason to be keeping people out. Yet the government is now saying that it may be next year before people are allowed back in. Absurd.

Major Projects

Other than the projects mentioned above, TEPCO is working on the following activities

• Removing radioactive debris from around the outside of the reactor buildings. This will allow recovery workers to work in this area without risk of excessive radiation exposure.
• Construction of a desalination plant to remove the salt from the water being pumped from the turbine buildings
• Pump the water in the turbine buildings into temporary storage.
• Erect a demineralization plant to clean up this water so that it won’t emit so much radiation.
• Further experimentation with flooding the Unit 1 containment structure to aid with cooling the reactor. No news release has said so but I’m of the impression that they’re about to give up on this, based on the concern that another strong aftershock might damage a water-filled containment. I think that the current attempt to purify the air in Unit 1, to be followed by connecting to the Reactor Coolant System with the closed loop heat exchange is the new plan.

Less Frequent Updates

Now that the emergency phase of the event is over with and the utility is settling in for the long task of recovery, there is far less information flowing from the company and the various English language news sources that I monitor. Just not that much to report. Therefore I won’t be writing these updates nearly so often. Only when something interesting happens.

Meanwhile let’s not forget about the true disaster. The quake and tsunami. The photo at left shows the utter devastation caused by the combination disaster. With the official death toll over 30,000, anything that happens at the nuclear plant is small potatoes. The media would have you believe that the nuclear plant is the center of the disaster. It isn’t. No one outside the plant boundary has been killed or even injured by the incident. Keep that in mind as you read both the major media and my reports.

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