Friday, July 22, 2011

Fantastic Friday: How About Some Music?

I have been having trouble with my blog radio as it will only play one song on the playlist now. I do not know what the problem is, but I might have to overhaul it if it continues. So, I will give you some music of a different nature this Friday.

For those of you who are unaware, there was a series of albums produced by Josh Homme of Kyuss and Queens of the Stone Age fame known as the Desert Sessions. The Dessert Sessions was a project of Josh Homme and various other artists who would go out in the middle of the Nevada desert, hook their equipment up to a generator and start playing to see what would happen. All five albums are entirely improvised and feature material from names such as Chris Goss and Mark Lanegan. The result is an interesting mixture of material ranging from psychedelic, drug-induced guitar haze, to acoustic folk and blues. However, it all evokes the feeling of traveling across a massive, sun-baked desert alone and stoned out of your mind; while your flesh broils in the blistering heat or is scoured by blowing sand storms.

All five compilations are well worth getting but some of them are sadly out of print. My favorite collections of the series are 1&2 but my favorite single song is probably "Making A Cross" from volume 7&8. It is perfect music for listening to while driving as well as a lazy afternoon on the porch with a beer or for a late-night shot.

Friday, July 15, 2011

Fantastic Friday: What A Week!

For today's Fantastic Friday I give you a YouTube series called Epic Meal Time. Epic Meal Time features a group of young Canadian men who get together to make some of the most outrageous and fatty meals in existence. Each episode features a dish with unholy amounts of meat and cheese and they make a point of using bacon in every recipe. The end result is a sort of meat-nirvana that only the most dedicated eaters can ever hope to attain. The main host pretends to be constantly drunk and angry, and the sound of a bird cawing plays whenever he swears. They have a whole bunch of episodes and they come out with a new one every Tuesday. This week's episode features the "Epic Stockyard Burger", a bacon, cheese, bone marrow, and beef monstrosity that is stacked and then deep fried. I pity vegetarians, as they miss out on bliss such as this.

Thursday, July 14, 2011

Nuclear Technology Basics: Part 8 Liquid Metal Cooled Reactors

Introduction

Part 1

Part 2

Part 3

Part 4


Part 5

Part 6

Part 7

Liquid metal-cooled reactors are both moderated and cooled by a liquid metal solution. These reactors are typically very compact and could also potentially be used for naval propulsion. While there are a few currently existing liquid metal-cooled reactors that are being used for electricity generation, most examples are prototypes that have been built around the world as experimental reactors.

1. Sodium-Cooled Fast Reactors (SFRs)



Sodium-cooled fast reactors use a sodium-potassium alloy that remains liquid at room temperature. While the compound reacts violently on contact with air or water, its effects on steel are minimal. This makes NaK a possible coolant and moderator choice for a fast neutron reactor such as this one. Using water as a neutron moderator would effectively reduce the speed of the neutrons to those of thermal neutrons unless it was under massive amounts of pressure, while the NaK coolant and moderator does not need to be pressurized.

Fast reactors have advantages over reactors of other types as they achieve a high fuel "burn-up" ratio and greatly reduce the long-lived actinides that are present in the spent fuel when compared to other reactor types. This has made SFRs an attractive energy option for many countries around the world. Unfortunately, the Integral Fast Reactor project (IFR) was cancelled in the US because during the Clinton administration because of political reasons despite only being thee years away from completion. As of yet, a standard SFR design has not emerged from one of the many prototypes that have been built.

The NaK compound is pumped through the bottom of the reactor where it is heated up by the core. Hot coolant in the primary coolant loop is pushed into the heat exchanger, which is used to heat up coolant within the secondary coolant loop and the heated secondary coolant is used to turn a turbine connected to the generator. After leaving the turbine, the coolant flows into a condenser connected to a heat sink to help absorb some of the excess heat energy. The cold secondary coolant is pumped into the top of the heat exchanger while the primary coolant enters to bottom of the reactor again, completing the cycle. The control rods are inserted into the top of the reactor vessel.

Moderator Type: Liquid metal

Technology: Generation IV

Existing Examples: Three, but many more are being planned and built.

Advantages

-This reactor design has a high fuel burn-up ratio.

-NaK does not corrode steel.

-The reactor design is very compact yet has a high power output for its size.

-Liquid metal-cooled reactors are not pressurized leading to simpler piping systems.

-The liquid metal coolant cannot turn to steam unlike water during a meltdown, making a steam explosion impossible.

-Some variants of this design can be used as breeder reactors.

Disadvantages:

-The high temperature of the reactor could also pose design challenges.

-Sodium reacts violently with water and air.

Variants: BN-350, BN-600, Clinch River, Dounreay Prototype, Fermi 1, Experimental Breeder Reactor 1, Experimental Breeder Reactor 2, Fast Breeder Test Reactor, Integral Fast Reactor, Jōyō, Monju, Phénix, Prototype Fast Breeder, S1G, S2G, SNR-300, Sodium Reactor Experiment, Superphénix, Rapsodie

2. Lead-Cooled Fast Reactors (LFRs)



Fast reactors can also be used with a lead-bismuth coolant and moderator. Lead has a low degree of neutron absorption and does an excellent job of reflecting neutrons. In addition, lead is a very effective radiation shield and its extremely high boiling point makes lead-bismuth eutectic (LBE) an effective coolant even at higher temperatures. While LBE is somewhat corrosive to steel unlike NaK, it is unlikely that this poses a major problem as this issue can be overcome with proper engineering.

The design of the lead-cooled fast reactor is is slightly different from that of the sodium-cooled fast reactor. the LBE coolant on the outside of the coolant module flows downward where it is drawn into a pair of chambers in the center. The core of the reactor is contained with in a block in the center as well which heats the coolant as it is pushed upwards towards the top of the coolant module. This design has a pair of heat exchangers that are inserted into the top of the coolant module with the control rods in the center. Primary coolant transfers its heat energy to the coolant in the secondary coolant loop through heat exchangers where it is sent to a pair of turbines. After circulating through a secondary heat-exchange system to cool the LBE down, the returning secondary coolant is pumped through the top of the reactor to be drawn into the reactor core to complete the circuit.

Moderator Type: Liquid metal

Technology: Generation IV

Existing Examples: None that have been completed, but several LFRs are in the construction phase around the world.

Advantages

-This reactor design has a high fuel burn-up ratio.

-The entire reactor core can be removed and replaced during refueling procedures.

-The reactor design is very compact yet has a high power output for its size.

-Liquid metal-cooled reactors are not pressurized leading to simpler piping systems.

-The liquid metal coolant cannot turn to steam unlike water during a meltdown, making a steam explosion impossible.

-Some variants of this design can be used as breeder reactors.

Disadvantages:

-Lead-bismuth eutectic is slightly corrosive to steel.

-The lead-bismuth eutectic coolant can cause problems if it is allowed to solidify within the coolant circuits.

-The high temperature of the reactor could also pose design challenges.

Variants: OK-550, BM-40A, SVBR-100, Hyperion Power Module, MYRRHA

Friday, July 8, 2011

Fantastic Friday: For the Love of Quake!

I am not much of a gamer. The games that I do like and play are mostly older games for classic platforms such as the SNES and the Sega Genesis. As such, my knowledge of recent games is somewhat lacking, because I find most current computer games to be rather lacking in originality or fun. This is because many PC games are little more than an exercise to show off the graphical capabilities of the game rather than the gameplay itself. This is particularly problematic with the first-person shooter genre of games as they all seem to be imitators of each other, complete with boring enemies and rife with cliches.

I despise the Halo series as I find the main character to be little more than your average mindless military grunt like you see in almost every first-person shooter. Bioshock had some interesting ideas, but far too many of them got cut out in the final two games of the series, as a quick glance at the concept art books will show you. The Half-Life series is a refreshing change from the usual first-person shooter pablum as its protagonist, Gordan Freeman, is a theoretical physics researcher rather than the usual big and stupid marine. However, one of my favorite older games of all time remains the first Quake game.

It was originally for the PC but it has come out on numerous platforms. Unlike its later sequels, the enemies of the first Quake game were a strange mixture of horror-inspired monsters and formerly human soldiers that had apparently been captured and augmented by the enemy to make them mindlessly obedient in carrying out orders to kill you on sight. The antagonists of Quake all had very distinct characteristics in terms of how they attacked you and what their strengths and weaknesses were. All of the enemies were very well thought out and implemented and the environments that you fought them in were extremely varied. The game had a rather sparse plot, as you were supposedly a lone soldier left behind in a base after everybody else had been killed, as an enemy that was codenamed "Quake" had come through a sort of interdimensional device that your base was working on before the attack.

The game had four "episodes" of levels that were somehow related to each other. You could choose which episode you wanted to play in after selecting which entrance of difficulty you wanted to enter at the beginning of the game. You did not have to play the episodes in a specific order, but the episodes increased in difficulty so it is usually advisable to start with the first episode as it was the easiest one.

The first level of each episode was unique as it featured some sort of futuristic military base. However, the "base" levels had the same dismal and oppressive feeling that characterized the rest of the Quake levels. The walls were dingy and scratched, and were often covered in blood stains. Pools of grimy water and poisonous sludge were not uncommon and while the "base" levels lacked the horrifying textures of some of the later levels, they did imply that the current inhabitants were nearly mindless and that they were not the original builders as the current denizens seemed to lack the intelligence or autonomy to repair or maintain these crumbling structures.



The enemies that you fought in the "base" levels consisted of shambling human soldiers called "grunts", along with rabid rottweiler dogs, and the slightly more dangerous "enforcers" which were like grunts that have been upgraded. Grunts were humans that had cybernetic implants put into their brains by Quake that gave them feelings of bliss whenever they killed somebody. Grunts are not much of a challenge to defeat as two shots with the shotgun weapon that you start the game with was more than enough to put them down permanently and their reactions and movements were slow. Grunts were only challenging in large groups as they were quite accurate with their guns and could overwhelm you if taking on too many at once. When defeated, you could pick up a grunt's backpack which contained a few shells of shotgun ammunition. Rottweilers were even less of a threat than a grunt because all they could do is run towards you and attack you with a lunging bite. They had even less defense than a grunt and two blasts would quickly make them drop. The enforcers, which were the resident "tough guys" of the base levels were tougher than grunts as they wore full combat armor and were faster and had more defense than a grunt as it took four shotgun blasts to defeat them. In addition, they had some sort of energy weapon that fired blobs of light that cause quite a bit of damage to your character if he was hit. Unlike the grunts which could only snarl or growl, the enforcer apparently retained some degree of intelligence as it could utter simple phrases like "HALT!", "STOP!" or "FREEZE!" when it spotted you. When killed, an enforcer dropped a backpack containing "cells" which was ammunition for the "thunderbolt" weapon which you got later in the game.

After completing the "base" level at the beginning of each episode, you entered the world of your antagonist, which was some sort of dimension filled with rotting castles or malign dungeons. While the grunts, rottweilers and enforcers were absent in these levels, you had scrags, knights, death knights, fiends, zombies, rotfishes, ogres, spawn, vores, and shamblers.

Scrags are floating enemies that look like a cross between an armless man and a snake. They spit some sort of poisonous blob of fluid at you with a high degree of accuracy and damage if it hit you. Knights were twisted humanoid creatures wearing rusty armor and wielding battered and blood-covered swords that they used to great effect if they ever managed to get close enough to attack you with them if you did not fill them full of buckshot or nails first. Ogres were brutish humanoids that carried small grenade launchers and held chainsaws in the other arm. They were one of the most common enemies in the game and their grenades could be a real hassle at times. Continuing on with the rather easy enemies, the rotfish were undead piranha-like creatures that would chomp on you in the water and could easily be defeated by a single shotgun blast. Zombies were undead corpses that attached you by throwing pieces of their own flesh at you, and while they could be easily knocked down by any weapon, they would quickly rise up again and start attacking you unless you blew them to pieces using your explosive weapons.

Later on, you would encounter the more dangerous, mid-level enemies such as the death knight, spawn, fiend, and vore. Death knights are larger, tougher, and faster versions of the regular knight and could quickly kill you with a few swipes of their massive swords or their magical ranged projectiles. Spawn are bouncing blobs of slime that would harm you on contact and had a nasty habit of inflicting even more damage when killed as they tended to explode in your face when defeated. The fiend was a highly aggressive, eyeless, and clever beast that reacted by quickly charging at you and lunging across great distances to tear you open with its hook-like forelegs and would quickly rip you apart with them at close range as they did a lot of damage. Vores are bizarre, tripedal creatures that send explosive projectiles that homed in on your presence when they spotted you and a vore could take a lot of hits before killing it.



The undisputed "king" of the Quake monsters is the shambler. Shamblers are hulking, foul-tempered beasts that could send a powerful burst of lightning to reduce you to a pile of ashes, or rend your body to bloody chunks with their massive claws at close-range. Their heads lack visible eyes; and large, jagged, and frightening teeth jutted out of their mouths. They could soak up a lot of damage before falling, and they were especially resistant to your grenade launcher and rocket launcher which were normally very powerful weapons in the game. A shambler stops at nothing to defeat its enemies, even if it means crushing any allied monsters in its way. The shambler is never something that you want to see or take lightly.



Although Quake is a "mess" from a concept standpoint, there has never been anything like it before or since. The mish-mash of varied monsters and environments just seems to somehow work within the atmosphere of the game and Quake revels in its morbid, chaotic, and violent glory. While violence in video games often comes off as being over-the-top to the point of being cartoonish or laughable, the muted palette of Quake along with the otherworldly level architecture make the grisly world of Quake a truly chilling experience.

While the following sequels of the Quake franchise featured a race called the Strogg, they were little more than boring rip-offs of the Borg from Star Trek. Quake deserves a true sequel, but making one that captures the essence of the original game would be very difficult as Quake has an intensity that is not easily replicated by many modern games. This is an example of a game that transcends genres.

Sunday, July 3, 2011

Nuclear Technology Basics: Part 7 Graphite Moderated Reactors

Introduction

Part 1

Part 2

Part 3

Part 4


Part 5

Part 6

Many reactor designs use graphite as a moderator. Graphite is not as effective of a moderator as heavy water, but it is cheaper and it also has a low degree of neutron capture like heavy water. This makes it possible to use un-enriched or natural uranium as fuel. Graphite is somewhat susceptible to corrosion and annealing because the moderator blocks are often located in the hottest part of the reactor. Graphite also has a tendency to expand with prolonged neutron exposure. However, modern reactor designs have mitigated these issues so graphite remains a viable choice for a neutron moderator. The earliest energy reactor designs were graphite moderated, but some generation IV designs also use graphite as a neutron moderator.

1. Gas-Cooled Graphite Moderated Reactors (GCRs)



These reactors use graphite as a neutron moderator, but use pressurized carbon dioxide gas to cool the reactor. The primary example of this reactor type is the now obsolete MAGNOX design, so named for the "magnox" alloy of magnesium and aluminum which was used in the cladding of the reactor's core. The MAGNOX reactor grew out the nuclear weapons production program in Britain, but it also served a dual role for energy production.

The reactor itself consists of a pressure vessel similar to the BWR, with the fuel rods inserted in the top of the pressure vessel like in the LWR. The fuel rods of the reactor are surrounded by blocks of graphite, serving as the neutron moderator. These are situated inside the pressure vessel where carbon dioxide gas is heated by the fuel rods and flows upward and out of the hot gas duct connected near the top of the pressure vessel. The gas is pushed through a heat exchanger where water circulating within a closed loop is heated by the hot carbon dioxide and the resulting steam is used to turn a turbine. As the gas cools, it exits via the cool gas duct at the bottom of the heat exchanger and is sent back to the pressure vessel where it is heated again to complete the cycle.

A more advanced type of GCR was developed from the MAGNOX reactor, which is known as the advanced gas-cooled reactor or AGR. The AGR is similar to the design of the MAGNOX except that the heat exchanger of the AGR is contained within the reactor vessel itself instead of being outside of it like in the MAGNOX reactor. The AGR requires its fuel to be enriched unlike the MAGNOX design because the cladding of the AGR is made out of steel which has a tendency to capture neutrons. The original design of the AGR used beryllium cladding but this proved to be too costly, as beryllium is a very difficult material to process because of its high melting point and its affinity for oxygen at very high temperatures.

The AGR was built to overcome some of the MAGNOX reactor's shortcomings as the AGR was specifically built for energy production rather than the dual production of military grade plutonium. It was seen as a potential challenger to LWR designs, as the AGR was designed to allow refueling while the reactor was still in operation like in the MAGNOX reactor, but the fuel rod removal equipment was shown to be very prone to failure. In addition the design of the AGR was overly complex which added to the costs of construction and operation. In short, GCR reactors have a history of being fraught with technical difficulties and it is unlikely that any more of these types of reactors will be built.

Moderator Type: Graphite

Technology: Generation I-II

Existing Examples: Eighteen GCRs continue to operate in the UK, both of the MAGNOX and AGR designs.

Advantages

-Using a gas as a coolant allowed for higher operating temperatures and thermal efficiency.

-Some designs can use naturally occurring uranium without requiring further enrichment.

-It is more efficient in its fuel utilization than light-water moderated designs.

-It can be refueled without having to shut down the reactor.

-The resulting spent fuel can be stored in a more compact manner because it generates less heat when coming out of the reactor as it is less reactive.

Disadvantages:

-The fuel rod removal systems of these reactors was prone to technical problems.

-The design of the reactors was overly complex it often led to malfunctions.

-These reactors were more costly to build and operate than some reactor types.

-The first reactors of this type were not optimized for power production.

Variants: MAGNOX, AGR

2. High Power Channel-Type Reactors
(RBMKs)




This was a Russian design, and it was the reactor responsible for the infamous Chernobyl incident. This was both because of inherent flaws in this reactor's design as well as the fact that the staff on duty during the Chernobyl incident had attempted to run an unauthorized experiment with the reactor during its operation. With that being said, this reactor type is now considered to be obsolete.

The Reaktor Bolshoy Moshchnosti Kanalniy (RBMK) means "high power channel-type reactor" in Russian. It was similar to the MAGNOX design except it was water-cooled instead of gas-cooled and it heated water directly into steam within a pair of steam separators located inside the reactor pit which was used to turn dual turbines for energy. Because of the graphite moderator, the RBMK can run on unenriched uranium and the fuel rods can also be changed while the reactor is still in operation.

Part of the problem with this reactor design is the fact that it had a very high void coefficient. As the reactor is water-cooled, increases in temperature and pressure can cause the coolant to boil away and turn into steam, and the intensity of nuclear fission rises as the heat increases as the graphite moderator enables fission to continue. The control rods in the Chernobyl reactor were also controlled manually rather than automatically during an emergency. The Chernobyl accident resulted in a loss of coolant flow, which caused massive amounts of heat to build up in the core of the reactor triggering a positive feedback loop. The overheated core immediately vaporized the coolant within the reactor causing a huge steam explosion, similar to that of an overheated boiler within a steam engine.

The resulting steam explosion scattered radioactive particles from the core for hundreds of miles. The graphite surrounding the control rods was ignited by the heat of the reactor core and the roof of the reactor contained bitumen which also started burning. The official death toll released by the Soviet government was a total of thirty one deaths, and most of these were reactor workers and rescue personnel but many more people were thought to be sickened by the release of radioactive particles. To this day, an exclusion zone surrounding the reactor has been declared off-limits to humans but wildlife appears to be thriving there and the degree of ambient radioactivity has dropped considerably since the incident. If the Chernobyl reactor had a containment dome over it like all modern reactor designs do today, the effects of the meltdown on the workers and nearby populace would have been negligible. However, while the Chernobyl disaster and the resulting casualties was indeed a tragedy that could have been prevented with the proper engineering precautions, it was by no means the most severe industrial accident in the modern world. When compared to the Bhopal incident in India or the Banqio dam collapse in China or the yearly death toll resulting from a fossil fuel-based infrastructure dwarfs that of Chernobyl several times over.

Ever since the Chernobyl incident, the few remaining RBMK reactors still in operation have had their safety systems updated to prevent something like this from ever happening again. As it is, RBMKs only exist in Russia. Because this design of reactor is considered to be obsolete, it is unlikely that any new RBMKs will be built in the future.


Moderator Type: Graphite

Technology: Generation I-II

Existing Examples: Eleven in Russia, one in Lithuania.

Advantages

-It can use naturally occurring uranium without requiring further enrichment.

-The reactor generated a lot of electricity with its dual-turbine design

-It can be refueled without having to shut down the reactor.

Disadvantages:

-This design has a very high void coefficient.

-The control rods were under manual instead of automatic control

-The safety features of this reactor design are obsolete

-The Chernobyl disaster has effectively ended interest in the RBMK design.

Variants: None, other than RBMKs with modified safety features.

3. High Temperature Gas-Cooled Reactors
(HTGRs)



Improvements on GCRs has led to interest in developing gas-cooled reactors with a higher operating temperature that would allow for a greater degree of thermal efficiency and a higher degree of fuel utilization than the previous GCR designs. In addition, these reactors are also of a simpler design and use gas turbine systems for power generation leading to a more compact turbine assembly. Unlike previous GCR reactors, HTGRs use helium rather than carbon dioxide as a coolant because of the fact that it is inert even at higher temperatures leading to less corrosion on the piping systems of the circulating coolant.

Early experimental HTGR designs such as the Fort Saint Vrain Generating Station in the US, and the THTR-300 in Germany experienced technical problems or financial difficulties. However, the pebble bed reactor (PBR) shows great promise. The PBR is revolutionary in that its fuel is contained within spherical pellets of graphite that are piled within a chamber inside the reactor vessel. The pyrolytic graphite shells surrounding the fuel cores serves as a neutron moderator while the helium gas that circulates through the spaces between the pebbles serves as a coolant, avoiding the complex piping systems needed for designs that utilize fuel rods. These fuel pellets are circulated through the reactor every thirty seconds or so to be inspected for damage, allowing worn pellets to be removed and new ones to be put into circulation without shutting down the reactor for refueling. In addition, the reactor can hypothetically use graphite shelled pellets of thorium or fuel made from decommissioned nuclear warheads. Finally, the PBR pellets lack the fuel density to allow a meltdown to happen making a meltdown of the reactor physically impossible.

Of course, the PBR carries its own disadvantages, mainly that the PBR design utilizes a once-through fuel cycle and the graphite-sealed fuel pellets are very difficult to recycle in addition to increasing the volume of spent fuel to be disposed of by up to fifty percent. While there is certainly no shortage of fissile material that can be used in a PBR, once-through fuel cycles that make it difficult to engage in nuclear reprocessing are inherently wasteful.

Even though the PBR was originally a German design, political pressure within Germany's government has effectively stalled any and all research for nuclear power generation for the foreseeable future. There was interest in the PBR in South Africa, but political hurdles surrounding the construction of the Koeburg reactor has scared away investors and the reactor project was mothballed in 2010 by the South African government. The only active PBR project that remains is in China where the HTR-10 prototype at Tsinghua University is scheduled to be commissioned in 2013.

Moderator Type: Graphite

Technology: Generation III

Existing Examples: None currently in operation.

Advantages

-The fuel pellet design makes meltdowns physically impossible.

-The reactor core is cooled by helium gas which is chemically inert at high temperatures.

-The coolant system of the PBR is cooled passively and its simple design eliminates the extensive piping of active cooling systems.

-It can be refueled without having to shut down the reactor.

-Alternative fissile fuels can hypothetically be made into pellets to be used by this reactor design.

Disadvantages:

-The PBR uses a once-through fuel cycle.

-The pellet design of the reactor makes the reprocessing of spent pellets very difficult.

-The graphite shells of the spent pellets increases the total volume of material to be disposed of by up to fifty percent.

Variants: Dragon, TTR-300, Peach Bottom Unit 1, Fort St. Vrain 1, PBR, PBMR

4. The Very High Temperature Reactor (VHTR)

The VHTR (Very High Temperature Reactor) is a generation IV design that could be said to be an extension of HGTR reactor designs. It is also cooled with helium gas and uses graphite as a moderator. The core of pebble bed VHTRs would be similar to the PBR while prismatic block VHTRs would have its fuel shaped into fuel rods that are inserted in holes drilled into the hexagonal graphite blocks surrounded by control rods. The helium gas would be heated by circulating around the control rods to be carried to a heat exchanger to heat up water to spin a turbine.

True to its name, the VHTR concept operates at temperatures reaching 1000°C. This would make it very useful for providing process heat to carry out many industrial applications such as cheap hydrogen production and hydrocarbon reactions. The reactor would be extremely safe in addition to having a very high degree of thermal efficiency because of its high operating temperature. While this reactor design would have a once-through fuel cycle, the VHTR has a much higher fuel utilization ratio and the resulting spent fuel would have a much shorter half life than fuel from traditional LWRs. Prototype VHTRs are under development in China and the US has expressed interest in the VHTR for its Generation IV program.


Moderator Type: Graphite

Technology: Generation IV

Existing Examples: None currently in operation.

Advantages

-The fuel pellet design of the pebble bed variant makes meltdowns physically impossible.

-The reactor is an extremely safe design.

-The reactor core is cooled by helium gas which is chemically inert at high temperatures.

-The coolant system of this reactor is very simple.

-It can be refueled without having to shut down the reactor.

-Alternative fissile fuels can hypothetically be made into pellets to be used by this reactor design.

-The very high temperatures lend themselves to higher thermal efficiencies.

-The reactor would serve a dual purpose as a source of process heat for thermochemical production.

Disadvantages:

-It uses a once-through fuel cycle.

-The pellet design of the PBR variant VHTR makes the reprocessing of spent pellets very difficult.

-The graphite shells of the spent pellets of the PBR variant of the VHTR increases the total volume of material to be disposed of by up to fifty percent.

Variations: PBR VHTR, Prismatic Block VHTR

Friday, July 1, 2011

Fantastic Friday: Best Macaroni and Cheese Ever!

I thought that I would share one of my favorite recipes of all time. This is a version of baked macaroni and cheese that is made with bechamel sauce. Although the reputation of macaroni and cheese has suffered immensely with those abominations in a box such as Kraft, you will no longer allow such culinary mockeries in your kitchen again. This is a simple and fast recipe that even the most inept cook will find success.



Included here is the sauce that you will need for the recipe.

As a bonus, I am including a rare recipe that I saved from a newspaper article many years ago. It is for "onion marmalade" which is a savory spread that goes well with roasted meats or cold cut and cheese sandwiches. It is made from onions that have been carmelized over low heat for a long period of time, making them mellow and sweet instead of their characteristic pungent flavor when raw.



Enjoy, everybody!