Of Limited Brain Bandwidth

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At some point a person has to decide that he/she is involved in enough activitites in life. This uncomfortable world of overcommitment is where I have been for a while. I’ve come to the realization that my consciousness has limited bandwidth and that intellectual stimulus can overload it in ways that are hard to recognize. 

Having been born with lots of curiosity, I find myself piqued by a great variety of things in the universe.  The sciency stuff is obvious. But there are other things that can consume much of my capacity for attention.  It is much like an addiction to a drug. One soon becomes accustomed to a high baseline level of stimulus.  As boredom sets in,  the brain seeks greater stimulus. I can’t bear to wait 5 minutes without something to read. Cable television and the internet takes full advantage of this.

Last weekend I found myself totally immersed in the Free Electron Gas theory of metals. As I was wrestling with the math my family was out shopping and having fun. I was having fun as well, but it was of a more cloistered form. Was I being selfish? I think the answer is yes.

So, this life of intellectual pursuit can spin into a solitary life.  I like to joke that some days I’m misanthropic and other days I’m very misanthropic. That’s not exactly true, but I will say that my patience for unstimulating conversation is limited.  It comes down to the fuzzy boundary between ambition and obsession.  It is very easy to slip into a condition that is referred to as eccentric.  I can see how it happens. Maybe it is too late.

Things to notice about the disasters in Japan

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Everyone is rightfully concerned about Japan and what is to become of the region around the Fukushima Dai’ichi generating station. The quality of information by the various broadcast outlets is improving somewhat in my estimation. What the rest of the world should take note of is the stoic and highly admirable manner in which the Japanese have responded to the earthquake*tsunami*nuclear-disaster trifecta that has fallen upon them. In a US city there’d be looting and widespread felonious mischief as local criminal entrepreneurs rose to the occasion.

Another thing that I hope is noticed is the manner in which the failures initiated and propagated at the power station.  The unfortunate low elevation of the emergency generators is the obvious one.  But there is something else that is dramatically affecting how the incident propagates.  If you look at the cutaway diagrams of the plant you will see the highly compact nature of the facility.  The footprint of the buildings are quite small given the amount of equipment and processing that occurs there. In particular, the location of the cooling pools for the spent fuel assemblies is at the upper level of the structure, above the reactor spaces. 

The upper level with the cooling pools has an overhead crane that can move along the length of the facility. The fuel elements can be pulled up and out of the reactor and moved laterally into the pool.   The General Electric design is quite efficient in the use of acreage. But in the event of a major upset with fire, explosions, major radioactive material release, and structural damage, the compactness of the facility and the elevation of the spent fuel cooling pools works for prolonged incident propagation and against termination. 

The very altitude of the cooling pool spaces presents a major hurdle to taking control of the situation.  Having this problem at ground level where you could directly apply resources to the event would be bad enough. But to have it many stories above ground places huge constraints on the responders.  Designers of power plants should be thinking about where hazardous energy can be released and how responders will deal with it. Problem- all facilities design projects are constrained by severe cost considerations. Designers prefer to think about the most efficient designs, not how their brain child is going to fail.

Credible Information on Fukushima

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It is difficult to find truly informed opinion on the Fukushima reactor disaster in Japan.  The Daily Kos Community site by Richard Blair seems very credible from what I can discern.  The writer claims to be a Nuclear Power Operations-certified systems engineer in GE Boiling Water Reactors (BWRs). I have no reason to disbelieve it.

Actually, Rachel Maddow (and writers) did a very even handed presentation this evening of the basics of reactors, radiation, and nuclear power generation on her show. 

Blair (writing under the pseudonym Richard Cranium) shares some interesting insights on the Fukushima boiling water reactors. It’s worth a look.  It is part of a larger effort at information aggregation called the Japan Nuclear Disaster: Mothership.

Bug Hunt: Los Angeles

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Big, angry, armored termite soldiers from the Planet “O” land off the coast of SoCal and make an amphibious assault. Luckily for humanity they land near Camp Pendelton. Thus begins Battle: Los Angeles. 

Filmed in a documentary style, this movie follows the travails of a platoon of Marines on a mission to pick up civilians at a police station in Malibu and take them to a forward operating base (FOB) before heavy bombardment of the coast begins. The aliens take and keep the initiative early in the invasion.

The invaders aren’t misunderstood ET’s with big blue cow eyes.  These bipedal and possibly cyborgish critters are loaded with high velocity rounds and are fiendishly single-minded in their attempt to secure the planet. Aaron Eckhart plays the lead character, Staff Sergeant Michael Nantz.  Along the way the platoon picks up USAF staff sergeant Elena Santos played by Michelle Rodriguez. The casting of Rodriguez was particularly smart from the marketing perspective. Hotties with automatic weapons are irresistable to the male moviegoer. I’m thinking of Ripley making her escape from the Nostromo.

OK, guys, this is not a chick flick. It’s not especially bloody, but it is filled to the brim with male bravado and long satisfying bursts of full automatic gun fire. Wives and girl friends may be unmoved by the machinegun aesthetic. Just thought I’d mention it.

It’s not Academy Award stuff, but it is worth seeing on the big screen.

On a separate topic, for the fans of Dune, there is this link.

China Syndrome in Japan

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The China Syndrome is a fanciful “theory” that postulates that when a nuclear reactor undergoes a meltdown, the hot core material melts through the pressure vessel and through the concrete containment flooring below into the ground. All the way to China. 

Well, this really can”t happen because the core, hot as it is and dense as it is, could only go to whatever depth matches it’s density. I don’t think many people really understand what happens to core material when it breaches the containment and encounters the subsurface. Further, it’s hard to say if the core material will remain intact as a single unit long enough to retain a critical condition as it spills outside of the reactor vessel assembly. 

The fuel elements are, I believe, ceramic in nature, making them refractory. Refractory materials have quite high melting points. A reaction mass that has some fluidity might well split off isolated blebs which could then take the whole mass away from a critical condition.  This would tend to dampen the reaction rate and allow the reaction mass to cool below the melting point of the mass.  

Quite apart from the dispersion of the core material is the loss of moderator around the reaction mass.  This would occur as the primary coolant water flashes to steam as the pressure vessel is breached. Loss of moderator reduces the number of neutrons in the resonant range and the power should drop accordingly.  The decay heat from the fission products should be fierce.

As a molten parcel of reactor core heats up the surface material below it, the molten flooring, soil, or bedrock must be fluid enough to allow the core to displace it downward. It could be that the blob gets elongated and increases the surface to volume ratio enough to allow the loss of neutron flux to cause the blob to cool below the melting point of the ground.   How a self-heating blob of core material behaves under the pull of gravity in a variable and possibly refractory rocky matrix is not an easy problem.

Ground water would be problematic for the neighborhood because eruptions of contaminated steam would be expected to issue from the crater.

I hope these poor fellows are able to get their reactors under control before the area gets too hot.  If the reactor spaces and control rooms get too hot it is going to complicate the remediation.

It is worth reading the updates from NISA.

Some Comments on Public Schools

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I know public school teachers very well. There is much talk about the kind of job public school teachers are doing these days. Much of the discussion is very negative.  A lot of people seem to think that American public school education is in some kind of decline.  Conservatives in particular seem to have a good deal of criticism to direct at public school teachers.

While I suspect that this grumbling on the right has more to do with vengeful, angry little boys who have grown to be vengeful, angry men, I’ll set this hypothesis on the shelf for some more aging.

In Coloado we have an annual test battery for public school students called the CSAP’s.  It was an initiative set forth by conservative legislators who have a very negative view of public education in general and of teachers unions in particular.  The CSAP’s start tomorrow in fact.  My 9th grade kid will spend the next week taking them. 

It is funny. No matter how tight the legislation is, people will always find a way to game the system.  I know of one principal who was selected to open a brand new elementary school nearby.  While at his previous elementary school in a poor neighborhood, he had access to the students CSAP scores. Prior to his departure he contacted the parents of the top 70 or so students and invited them to come to his new school in a more affluent neighborhood. Nearly all of them did, leaving the previous school in the lurch.  Test scores plummeted at his previous school last year because of this. The parents of the recruited students had a good many volunteers among them. The level of volunteerism dropped substantially as well, adding to the workload in a school already depleted of hourly teachers aids.

Yes, the aforementioned principal seems guilty of some kind of malfeasance or corruption. He’s gaming the system. But he fell out of the sky into a system begging for gamesmanship.  He did it to pave his way into a superintendant slot someday and I’ve no doubt that he’ll get it.

The great fallacy of this issue in the public forum is that it is up to teachers alone to keep kids on track.  Having been married to a special education teacher I can say that there are a great many parents producing kids that are improperly wired, emotionally disturbed, sociopathic, and/or neglected or abused.  Many kids go to school hungry and go home to high stress environments where there is rampant drug abuse, alcohol, and family violence. 

It is not uncommon for some elementary students to be the only family members who can speak English.  Parents in such homes are not able to help with home work. They are not able to communicate with the schools owing to cultural aversion to such contact or because they are undocumented.

I believe that our culture has changed considerably since my age cohort was in public school.  College was a distant aspiration for many of us.  College was not needed to work in the trades. We could get on-the-job training or attend some kind of trade school.  Or, join the military.  These were the options. We had been to the moon, tamed the atom, and built massive industrial capacity for manufacturing an ever growing array of widgets and medicines.  Arguably, something was working well if industrial output is the measure.

But over time, with greater affluence in the US and abroad, the technology gap between the US and other nations began to shrink. Other cultures were developing their own magic dust and secret sauce.  The advantages of the US system began to diminish relative to other cultures. But the one thing that didn’t change is the bell curve.  As a population we still produce offspring who populate the bell curve of abilities and interests. 

I suspect that we have begun to intepret the “below 50th percentile” population in the various bell curves in a most disturbing way. Could it be that we are interpreting the very existance of the low academic achieving population as some sort of educational or societal failure?  Are we expecting modern education to skew the curve toward the high end against the natural spread of abilities and aptitudes in our culture?   Is the notion of excellence skewed towards academic achievement rather than the myriad other activities that make a productive life? Is high academic achievement the only acceptable result of education of our population? 

Not everyone needs to be a scientist or an engineer or astronaut.  We need to continue to identify youth who have such interests and aptitudes and carefully cultivate them toward such opportunities.  But we also must pay attention to those who have more ground based aspirations and abilities and value them just as highly.  It is like a food web.

The notion that we should engineer our schools to produce more super achievers is faulty and unfair to the 99 % who won’t become scientists or astronauts.   Even if we could multiply the population of scientists, engineers, and astronauts, the economy cannot accomodate them. Such professions are near the apex of the career pyramid.

I have come to believe that US culture has failed a large number of its youth.  Just look at the rates of incarceration in the USA.  A culture truly concerned about the wellbeing of its individuals wouldn’t have a few million of them in jail.  Could it be that the conditions in which we imprison citizens reflects what we truly think about individuals?  I think the current malaise in public school education manifested as high dropout rates and low achievement  and the epidemic of convicted felons may be connected as part of a larger failing of our society.

Nuclear Emergency in Japan

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The recent earthquake in Japan has triggered an actual nuclear emergency at the Fukushima Daini nuclear power plant. According to IAEA, the explosion earlier today originated in the Unit 1 reactor building and was not the result of explosive breach of the primary containment. One character interviewed on CNN called it a six sigma event.

If memory serves, water dissociates at ~2300 C. The cracking of coolant water by overheated fuel elements would result in the generation of noncondensable gases (H2 and possibly O2) that would add to the pressure excursion. Venting is the only option at that point. This was an issue at TMI. The explosive concentration range of hydrogen is very wide.

IAEA goes on to say that Units 1,2,and 4 are experiencing increased pressure, but Unit 3 is in a safe cold shutdown condition.  Tokyo Electric Power Company received permission to inject boronated seawater into the Unit 1 reactor.

This is very ominous news. Plainly, if the cooling loops were dumping enough energy out of the reactor they would not inject corrosive sea water into it.

There is a lot of talk about a meltdown.  As of this post, nothing has been disclosed about the actual state of the Unit 1 reactor core.  There has been no word on the state of the fuel elements or the state of the coolant loops.  I assume that the reactor design has a negative reactivity coefficient that will attenuate the reactivity with water coolant loss or void space formation.  The link on reactivity coefficients delves into a number of interesting and perhaps not-so-intuitive effects on reactivity during an upset condition.

Extractive Metallurgy as Inorganic Chemistry

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I am involved in an extractive metallurgy project 1 day per week give or take.  So I have been trying to take apart undesirable minerals in an ore to concentrate the desired metal. It’s called beneficiation- a word introduced by Agricola in his book De Re Metallica published in 1556.  I can’t disclose what the desired metal is.  Suffice it to say that it is rather scarce though not a coinage metal. 

What really amazes me is the disconnect between what many of us think of as the field of inorganic chemistry and the field of extractive metallurgy.  In my training as an organikker, I had never been exposed to extractive metallurgy, nor did I even know what it was.  Turns out that it is a field of applied inorganic chemistry. In this field, a metallurgist is the person who figures out how to extract desired metals from ore.  Nobody seems to call them a chemist, at least to their face. They’re the metallurgist.  No doubt there are exceptions.

Well, that clears things up quite a bit. I feel better getting that off my chest.  I’m sure any wayward metallurgist who happens upon this site has already begun to laugh. Extractive metallurgists do synthetic inorganic chemistry. It’s just that they prefer to keep company with a gangue of engineers and geologists rather than those who don’t work with minerals.  I can relate.

On the Digestion of Rock

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A rock consists of one or more minerals that may be held together by a cementitious binder. Or a rock may be a continuous mass of interlocking crystalline domains.

Igneous and metamorphic rocks are comprised of crystalline phases compacted into an inhomogeneous mass. Amorphous phases may be found as well.  Sedimentary rocks are often made of distinct mineral grains or pebbles held into position by cementitious matrix. There is a great deal of variety to be found.

The point is that rocks may have quite complex compositions. If the goal is to use rock for construction, then the composition may not be that important as long as some minimum structural attribute exists.  

But if the goal is to extract specific components from a rock, then the details of composition become very important.  Rock may be made of simple inorganic compounds.  Good examples would be calcium carbonate, sodium chloride, or calcium fluoride.  These substances are often found in crystalline form where the crystal consists of cations and anions which are free to solvate in the right solvent system and dissolve. These kind of minerals may be very weak structurally and subject to easy fracture.  The geological fate of such minerals is often aqueous transport and deposition to some location where a new mineral may precipitate from component ions in solution.

Some rocks may have appreciable fractions of monomers like silicate and aluminate. Monomeric components are able to form polymer networks which have a large effect on many properties of the mineral.  Glass and quartz are silicate network polymers that form rigid matrices. Silicate has 4 attachment points in a tetrahedral array that can form a variety of  linkages.  These matrices have properties like elevated melting point and rigidity that add or detract from the value of a given material. 

Quartz is a pure SiO2 network whereas soda glass contains network terminating additives that alter the connectivity and lower the glass transition temperature and melting point of the material. The additives lend workability to the glass. Chain and network termination no doubt has a major influence on the physical properties of rock.

Most metals are found in nature as an ionic compound in various oxidation states and charge balanced by simple anions like oxide, sulfide, or a halide.  Metal cations may also be associated with complex, polyatomic anions like sulfate, molybdate, tungstate, silicate, aluminate, and a few other oxidized species.  A few of these polyatomic anions, especially silicate, are held together with substantially covalent bonds. So their network polymer compositions may be very high melting and difficult to mill.

Extraction of desired metals from a rock will follow a path depending on the the type of mineral present. Rocks made of an ionic compound and not subject to network connectivity maybe susceptible to chemical attack and dissolution.  Treatment with strong acids or various fluxing agents may cause the digestion of a rock under less than drastic conditions. Such rocks maybe susceptible to weathering as well.

Rocks with substantial polysilicate or polyaluminate compositions are rather more difficult to digest. For the same reason glass resists most chemical attack, so too do silicate and aluminate minerals.  But substances that attack glass and alumina may also be useful in digesting rocks high in silicate and aluminate. In particular, hydrogen fluoride stands out. This acid is well known to attack glass by breaking the Si-O bond and making an Si-F bond due to silicons affinity for fluorine.  Digestion of silicate minerals with HF or ammonium bifluoride (NH4FHF) has been known for a long time.  The use of disulfur dichloride (S2Cl2) has been reported as well.

Silicates and aluminates are also susceptible to attack by hydroxide or carbonate.  This is often taken advantage of in the lab through the use of a muffle furnace and crucible. Digestion of a rock sample is affected at high temperature and the resulting digested material is then treated in a manner as to allow the separation of the metal as, for instance a hydroxide or carbonate that can then be ignited in the muffle furnace. This time a purified metal oxide is formed and weighed to give a yield or wt %. Metal oxides can usually be dissolved in aqueous acid and subjected to a variety of tests thereafter.