The Impossible Stories of the Tea Shop
or
The Cherry Blossom Project
"Someone gives you a billion gold and a doctorate and you build a nuclear power plant." Lady Mai sounded much less than impressed by the huge concrete edifice towering over her head. She no desire to feed the ego of Azula by feeding her yet more superlatives. Azula had made her fame in physics by researching nuclear fission and writing a revolutionary thesis, paper only other physicists could understand and large and important book called 'Nuclear Fission and Its Civilian Applications'.
A list of superlatives described the first civilian nuclear power station.
The site sat on five square kilometers of Chameleon Bay seaside and from the sea, its huge stacks and clean concrete domes impressed the technocrats. Mai had seen them. She had seen the forest of construction cranes over the largest Post War construction project in the Realm – towering amber towers to Azula's persuasive ideas. Azula had just turned twenty eight and she had a city of electricity built to her specifications albeit scaled up from the Five Megawatt Graphite Gas Reactor she had built at The Heijun Research Station north of Ba Sing Se. The GGR had impressed more than her thesis supervisors. The National Electricity Co operative of Ba Sing Se and The Electric Machine Industries Corporation of The Dominion wanted nuclear power stations to meed burgeoning demand for electricity. Ba Sing Se needed a solution to their pollution problem caused by dozens of electrical stations burning coal to meed their needs and nuclear power provided a perfect if somewhat mysterious means to solve pollution problems. Or at least promised to delay the problems long enough to make it a problem for later generations.
Azula disliked Lady Mai and had not expected the dainty and formal Lady of the Fire Nation to show up at a construction site.
Azula looked into the huge steel lined pit, some twenty meters deep and twice that across.
"The graphite moderated core and control gear will one day sit in this pit." Azula walked out across a steel beam that formed part of the supports for the core. "All this will be five meters below the level where workers will access the fuel and control rod systems. When this reactor begins operation, the core will be three hundred degrees Celsius and carbon dioxide will flow through channels in a gym sized graphite core to cool the fuel and carry the heat to make steam."
"In total, you will have four two hundred and fifty megawatt generators on this site." Mai added condescendingly. "I've been listening to you all morning."
Azula walked back on the steel beam.
Karo walked up to the lip of the reactor vessel. He bowed to Lady Mai and then looked at his clipboard. He never could quite convince her of his intelligence and yet had become a top notch mechanical engineer. Was it his freckles and his calm? Was it that he had hung out with Azula and likely was gayer than a lab full of monkeys on dope? Azula had a long lesbian resume so Karo wasn't courting her. The name 'Cherry Blossom Reactor' had come from his mechanical deigns which made the piping of the bottom of the reactor look like a cherry blossom.i
"Excuse me? Did I interrupt something?" Karo asked defensively.
"How many arc welders did we loose this week?" Azula stepped off the beam and glowered at Karo. She had discovered the building of a small scale nuclear reactor an enjoyable learning experience but she didn't have the detail oriented mind to put up with the minute details of building something that required attention to uninteresting details. Arc welders, riveting guns and the odd truck had gone missing and her sponsors wished for a precise accounting of these losses. "Chances are they're sloshing around inside the water tunnels under this place."
"I forgot to welcome you to Chameleon Bay, Fire Lady Mai." Karo turned to the her, "I hope I didn't appear rude but Azula has me doing the accounting."
"When they steal a heavy construction crane, then someone will deal with the thieving around here." Azula crossed her arms and faced Karo. "As long as it isn't either enough nuclear material to fission on its own as they say. Anyhow, the stuff will turn up. Half the pawn shops in Ba Sing Se must be selling off our equipment."
"This isn't anything hardware related but because this place is as huge as a city," Karo blushed, "I rushed over from the office block to inform you I received a call informing me that Fire Lady Mai will soon be visiting us and we're to extend all diplomatic courtesies." Karo cleared his throat. "I did try my best but the battery in the jeep has gone missing and so I had to leg it over here."
"That hardly inspires confidence." Lady Mai needled Azula.
"I design reactors, I don't do accounting." Azula pointed a slender finger at Karo. "He crunches the numbers for our employers." She crossed her arms and eyed Mai sternly. "In any event, this isn't our fault. Our security consists of a guard in a hut with a phone to the office at a surveyors mark on the main road. We have no fences or other security measures. The locals can walk right on the property and nick stuff. This situation will not improve until we start taking shipment of nuclear materials and equipment next year."
"I have my own security detail guarding the Royal Yacht." Lady Mai smiled slyly. "Do you need their help?"
Aang had come for a plant tour a week prior to Mai. Azula suspected Aang had sent Mai as an anti nuclear envoy. The Avatar had done this before and it annoyed Azula to no end.
Fire Lord Zuko had supported Avatar Aang's unwavering opposition to the construction going on at Chameleon Bay. Fire Lord Ozai had experimented with nuclear fission in an effort to make either a radioactive dirty bomb or a fission bomb (his scientist knew they could fabricate the former, but the latter produced more pleasing destruction). Avatar Aang feared such a plant could supply gigantic amounts of material which could never be disposed of and could become weapons.
The Northern Water Tribe King Arnoon feared the plant with its four massive reactors could poison their fishing grounds off the coast. The plans for the giant plant didn't call for the plant to discharge radioactive waste into the sea, but the sea water cooling the turbines would enter the sea at high temperature. The Northern Water Tribe feared fish die offs and had come to 'suggest' mixing ponds to mix the warm outgoing water from the plant with cold seawater to prevent fish kills.
A group from The Northern Water Tribe had come to see Chameleon Bay. They had even asked and been granted a tour of the experimental GGR Azula had built. Azula could rank the GGR as one of her finest achievements because it had run for four years and never had an accident. She failed to convince the Water Tribe representatives that safety record was not mere luck.
The role of 'nuclear defender' was not one Azula enjoyed. She had designed the reactor systems but the steam turbines and sea water steam condensing systems had come from various engineers working for various industries from coal fired power plants to locomotives. Her reactor consisted of a carbon dioxide cooled graphic moderated design that used natural uranium metal as 'fuel'. Azula had intended it to cool itself using convection as pumps and other devices could fail. She imprisoned it in a concrete box three meters thick on a side with a dense steel and concrete lid. The control rods and fueling tubes were accessed through this lid. She had designed it to be simple: she had no staff and had to run it with two graduate students. If it screwed up, she could leave it and walk away.
The sea water cooling system the fisherman disliked wasn't her design. When engineers designed the scaled up version of her reactor for power, Azula inisted they used well tested technologies for making that power. As a physicist, she was revolutionary but as an engineer, she was evolutionary and preferred to recycle old technologies if they were well tested and reliable. Her experimental reactor had used simple air cooling to take away the heat of the reactor, but this time, the heat was to be put to use to make electricity. Letting the heat drain to the air wasted the heat energy and now the mighty atom had to make a living. Coal fired power plants used fresh water and boiled it, used the steam to drive turbines to spin generators and make electricity or heat. Large plants recycled this water through the boiler but had to condense it to water. The coal plants on the coast used the same simple seawater system for cooling the steam and it worked efficiently and cheaply.
The Royal Yacht Roku had seen better days. The paint was fresh, but the ship looked small compared to the huge ocean liners of the modern age. The interior was lush mahogany, teak and tropical hardwoods but the decks needed a new coat of varnish and the brass needed polishing. The dining room could seat twelve and the low wooden table along with the icons of Fire Nation culture, the red and gold dragon themed carpet were luxury. Karo felt like he was entering a Fire Nation restaurant and the room looked 'bland' compared to luxury dining halls where passengers had invitations to sit with the captain at his table.
"Where are the chairs?" Karo looked at the low lying blonde white table and at the pink cushions. Azula had tried to educate him on some aspects of Fire Nation culture and Karo had an anthropological attitude toward them. He had learned traditional formal dinners involve sitting on cushions at a low table and eating fermented cabbage. He had the same attitude toward the Fire Nation ways of doing things as anthropologists had to tribes who ate the brains of the dead – he didn't pass judgment but was not prepared to take part.
"As you know, Avatar Aang has some concerns about this 'new' kind of power." Lady Mai watched with quiet bemusement as Karo struggled with the chopsticks. As a physical comedian, he had some talent. "The Dominion and Ba Sing Se plan to use it, but the rest of The Realm isn't convinced it's safe or necessary to split atoms."
"We have coal plants that spew out toxic sulfurous gasses and each year people die in Ba Sing Se from respiratory illness caused by pollution." Azula countered with a line she had learned by rote. "Call nuclear power the lesser of two evils but we had nothing else to supply our needs given our huge demand."
Karo dropped some kind of meat ball on the table cloth and looked at it wondering what to do next.
"Why did you come here?" Azula ignored Karo as he let another meatball slip out of his grasp and onto the plate. "Taking the grand tour of construction sites? Sick of my brother's athletic build so you decided to see hot, fat sweaty construction workers do their thing?"
"We have lot of those but I guess you don't need to be fit to run a concrete truck." Karo looked at his plate. "As an aside, does your country have frequent famines caused by impossible to operate eating utensils?" Karo held his chopsticks with great clumsiness. "I regret being rude but I can't work with chopsticks."
Mai snapped her fingers and a young servant girl with black hair in a neat pony tail came out. Mai whispered something, they both laughed quietly and the servant girl walked out of the room.
"We do have silverware." Mai told Karo politely.
She turned to Azula.
"The Avatar wants to keep an eye on this place." Mai said sternly. "Like anyone, I need a vacation from the palace so I tour the world with the Royal Yacht. I find the sea air relaxes me and refreshes me."
The servant girl returned with a pink napkin held closed by a pink napkin ring and bowed as she stood in front of Karo.
"You may have a better time with this – young man." She smiled and placed the folded napkin on the table. She trotted off to enjoy a good giggle at the uncultured Karo in private.
Karo undid the napkin and placed the fork, spoon and knife in their proper places. He put the napkin on his lap – normal in his mind but weird by Mai's standards.
"Will he be sending spies out next?" Azula took Mai to task. "Will I head out one morning to inspect the site and find a sky bison in camouflage hiding behind the turbine hall? I'll walk right past a big furry six legged thing because he has birch branches taped to his head." Azula twirled a rice noodle around her chopsticks to show off to Karo. "You can tell him we have reached the point where most of the physical plant has been constructed but the equipment is yet to be installed. We're on schedule but he'll have to wait about a six months to a year for the first reactor to go critical. We likely will be ready sooner but then we need to conduct tests."
"What kind of tests?" Lady Mai motioned with her chopsticks.
"Power plants have to perform perfectly and deliver power without fail." Azula explained somewhat pedantically. "If it fails, customers have blackouts; an annoyance in a household, very dangerous if the street lighting goes out or even deadly if the hospital can't function. Our tests will involve technical details like how much power gets lost on its way from our generators to the city, what kind of demands we need to meet. Do we need to operate the plant at full power at night because if we don't need to – we can save wear and tear and money. How long does it take the operators to bring this place to full power? We need to know this if we have a sudden surge of demand from the football stadium playing a night game or the hockey arena during the playoffs." Azula sounded confident she had explained matters but decided to be pedantic. "We think this plant can go to full power in an hour but we like to know for sure – eh?"
Mai looked to the uneasy Karo as he ate.
"Do you have anything to say?" She teased.
"The National Electricity Co - op needs to cover the costs of running this plant," Karo looked at his fork and the meatball now sticking firmly to it, "and customers wish to pay only for the electricity they actually use." Karo deftly balanced the spoon on his finger. "Nuclear power will provide 'base line' power for the city. That means it will become the main electric power station for ten million people. It will always be on but at times like the night, demand is low so we can reduce our output so we don't have waste. In the morning, people cook breakfast, factories and commerce picks up and we need to come on power. Sometimes, we will have all four reactors at full power and yet not have enough so we will turn on the coal plants as needed. We're the star of a play and so we need to know how to play our part so the performance goes on without a hitch."
Mai nodded. "What could happen if something went wrong?"
"What an ambiguous question." Azula dryly commented. "If we don't generate enough power when needed, a district could lose power. If we have too much power, then the surges can cause transmission lines to overheat and fail, substations can trip out to protect themselves. Much the same thing happens when lightning strikes power lines."
"The Avatar has concerns that if your reactors fail, then this place could be made uninhabitable for centuries." Mai sensed evasion but she didn't think Karo capable of it. She had met with Zuko and Aang and discussed the possibility of a horrific accident if the plant failed to work as planned and they worried if the reactors ruptured, the damage to the oceans and land could be horrific. Aang didn't like Azula's answers and thought she was evasive.
"A coal fired plant does this already by giving off smoke and poisonous gasses into the air and this seeps into the waters." Azula countered. "Mercury levels in Ba Sing Se waterways and in the fish has already rendered them unfit for human use. This will not dissipate for centuries." She glared at Mai. "The reactor gives off radiation during the fission process and the core would kill you in a minute or less." Azula's voice began to rise. "That core will sit five meters below the level of the five meter thick reactor lid inside the dome. Once completed, carbon dioxide will cool the reactor core and it will run at three hundred degrees Celsius when going at full power. Nothing can live inside the reactor chamber but then again nothing can live inside a coal burning furnace either. Five meter thick concrete walls of the reactor vessel keep it contained. The containment dome over it is that thick as well – and that dome while architecturally pleasing, isn't required. We added it only because we wished to allay any fears about this plant. The water for the turbines doesn't come into contact with the hot gas but passes though a special heat exchanger inside a separate five meter thick walled block separate from the core chamber."
Mai understood she had insulted Azula which gave her some small pleasure. Mai had reviewed the plans with Fire Nation experts who understood her work and understood the basics of what would make this place function.
The expert nuclear physicists from the Fire Nation had admired the design for Azula's research reactor. Azula used inert carbon dioxide at low pressure and unlike other proposed designs, her reactor dispensed with the circulating pumps all together. Carbon dioxide held heat very well and the graphite moderator couldn't melt. The hot gas rose out of the reactor, the colder gas entered in. The leaking coolant would waft out, not explode out. They admired the fact the design could use natural uranium metal as fuel. This eliminated the need for refining or enriching.
The same experts built a small reactor to play with and this made Zuko nervous and angry because the scientists didn't ask him for permission to build one. Zuko didn't want his experts tinkering with fission for fun. He demanded a report and took comfort in the very real criticisms his experts had of this 'achievement'.
The core had to be huge to make significant amounts of power. The experimental one Azula built took up a huge volume – the size of a full grown coal furnace used for power generation – while putting out one percent of the power. The reactor proved a pain in the ass to keep operating – it wanted to shut itself off if anything fell out of specifications.
They had tried to break the reactor – this made Zuko even more surly and almost cost the experts their jobs. As fortune and the fussy nature of the design would have it, overheating the thing proved impossible but they didn't tell Zuko they had a good try at making it catch fire, overheat or blow up. Although it would have given Zuko and Aang a very good reason to stop the march of progress toward nuclear power, her design included a heat activated system that dropped the shut off control rods into the reactor. They nearly all had heart attacks when they heard the thump of the rods dropping into the core. After that mishap, the reactor refused utterly to do anything exciting.
As if to add a slap in the faces of the experts reporting to Zuko, Azula's experimental reactor had no easy method to retrieve the shut off rods once they had fallen all the way in. The 'experts' fired off a telegram explaining their work and asking Azula how to raise the control rods to restart the thing. She had never faced the problem because as she wrote 'she had never been stupid enough to let it overheat'. They finally worked out that the 'coat hanger trick' used to unlock cars could raise each rod if they used sturdy enough wire.
They shut down the reactor and undid a good many fittings then lowered a cable with a fishing hook at the end. With the hook, they snagged the top of the control rod and heaved it back into position, tied it off by rope, reattached the electromagnets used to keep the rod in place and redid a good many fittings.
Zuko had instructed his spies to read their outgoing mail and had full knowledge of their control rod screw up. This did little to please Zuko, who thought the reactor should sit abandoned under the stands of the tennis stadium for the Royal Fire Nation Military University. As this facility was in the middle of a large post secondary institution on the edge of the capitol and Zuko worried a good deal more than his father about killing his subjects; he demanded the thing be shut off at once.
The experts shut the reactor down but had no idea how to dismantle it. Most of them soon left to work with Azula's group or other private firms to build really, really big reactors. For public safety and because a layer of wood lay between the reactor and the stands, the tennis stadium was closed permanently.
Katara came to Chameleon Bay in late fall. Azula agreed to put her and her father up in the guest cottage at their home in the nearby village of Tamgai. The leaves had fallen and the wind blowing across the bay had acquired a late fall bite.
Katara stood on the concrete road between the main reactor buildings and the huge buildings that housed the pump house and the vast electrical substation. In the six months since Mai had visited, Chameleon Bay had begun to look like a complete power plant. She was powerless to attempt any bending – something in the plant made bending impossible. She felt 'blind' because she knew sea water sloshed in vast tunnels under the plant and in pipes all over the place, in the damp air around her – as self evident to a water bender as the huge domes themselves. Cranes towered over the site, the cold wind strummed their cables. Aang had told her of the sheer size of the site but she found the gray concrete buildings an oppressive, looming presence. The four reactor domes had risen up in a year to become the largest domes ever erected without bending.
Azula had made this place.
The woman with the gold hair pin walked up to Katara with a clipboard in her hands. Katara nodded as she approached.
"We have finished the core of Reactor One." Azula winced as a gust of wind struck her face. "So far we've had no delays."
Katara considered Azula a good friend and regretted the way circumstances had put them at loggerheads. Her husband, Aang, did not approve of nuclear energy. The vast majority of denizens of Ba Sing Se and their king and coucils supported the project as it would bring back clean air and help clean up the chronic pollution of the last few years.
Azula handed Katara a pin in the shape of a rectangle.
"We have begun taking delivery of fuel and so everyone must wear this." Azula said reassuringly. "It's a dosimeter – the lab checks them to measure exposures." Azula then smiled as she put her arm around Katara and showed the metal strip pinned to her vest like a military medallion. "You're in absolutely no danger but we track radiation levels as a matter of policy. Call it scientific curiosity."
"Avatar Aang asked me to convey his greetings." Katara pinned the pin on her coat.
"He's not very welcome here." Azula spoke with some anger. "He has not treated us well at all. We're scientists and engineers working to build a power plant, not weapons makers and yet he treats us like we've set out to kill people and destroy the planet." Azula shivered. "I find that insulting."
"I can give you the full tour." Azula motioned toward the tempered glass doors of the front lobby and office block between the two legs of the huge H shaped building. "Follow me."
"He worries about unquestioned progress." Katara followed Azula and fiddled with the pin. "He grew up in a different age. He doesn't bother just you. The oil industry has no love for him either." She walked through the doors. "Can I ask if there are any risk to me in my ability to have children?"
"You had two already, how many do you need?" Azula gave a typical Azula remark. "You don't have to worry. You will have less radiation exposure in this building than sitting on the mountain top of the Southern Air Temple for an afternoon sipping tea."
The art nouveau movement had influenced the look of the lobby which had granite floors with fancy mosaics of things electrical. The walls had a pleasant beige color and the ceiling had drop down ceiling tiles with large square light fixtures set in them. To Katara, the lobby and office décor conveyed a business like atmosphere. She had expected a nuclear plant to have few windows as it had so much danger to keep confined and yet the office block was lit by large windows.
"We will provide tours once we become operational." Azula guided Katara across the office block. "High school science classes from Ba Sing Se most likely – although the public can also tour this place."
The vast concrete roofed turbine hall with the four turbines had a floor that had piping of all diameters laid out in a color code that held meaning for the engineers. Katara and Azula walked across the vast space on a sturdy shining steel catwalk. Azula's engineering reminded Katara of things the Fire Nation had built.
"These four turbines will take the steam from the two reactors." Azula stopped and leaned over the rail of the catwalk. "We will have Reactor One online in a few months with Reactor Two running three months later. We'll then finish Reactor Units Three and Four in the next year."
"Why not bring them online at the same time?" Katara's eyes followed the curve of a yellow turbine cowling.
"We can't. We need the time to hire the engineers and technicians to run the plant and uranium mining and smelting are new industries. We don't even have the full fuel load to start Reactor One." Azula explained. "The uranium mines and refiners have to ramp up production to make the fuel in enough quantity to run this place." She raised her hands in a gesture of helplessness. "For example, one mine supplying us used to mine silver and sold uranium by the pound to make colorful ceramic glazes and glow in the dark paint for clocks. Now they have to pull uranium ore out of the ground by the ton – we need one hundred and forty one tons for each reactor. They have found a willing customer for its once useless tailings – this made the owners happy, but it takes them time to scale up their operations."
The tour led Katara down halls with piping running along the ceiling, white concrete walls and cold concrete floors with a coating of drab yellow paint.
To Katara, the plant had much in common with the caves they had crossed to reach Omashu except these were square, lit by electricity and had brightly colored pipes, signs and fire extinguishers. She followed Azula onto the roof.
"This is the suppressor stack." Azula pointed at a huge, four story tall tank and an equally tall coil of pipes with fins spaced to allow air to flow through. "It will hold water. If the core overheats, the gas passing through the steam boiler will pass over a plug made to melt at 350 Celsius. The water in this tank will trickle down through spray nozzles on the pipes in the heat exchanger and 'suppress' the heat. We can also use it to turn on steam production through what we call 'injectors' if we need to do so after a leak or if the boiler boils dry."
"Why do you need it?" Katara looked up at the shiny tank.
Azula shook her head because she disliked asking so many questions she considered self evident. "All thermal power plants – those that make steam – require suppressors to deal with malfunctions in the steam system. If the boilers make too much steam the turbines could be damaged – turbines are hand made of exotic materials and so worthy of protection. If water leaks into the turbine circuit then the blades will corrode or get pitted – again a write off. In this plant, the suppressor also functions to wick away extra heat from the core during a shutdown so it will cool off in a manner of a few days – not weeks. This means we can go in and fix the problem." Azula pointed to tall white stack pipes. "While the reactor can't do anything dangerous, it makes no sense to let a steam accident write off some damn expensive generating equipment."
"Do you think this could happen?" Katara walked around the huge 'suppressor'.
"We've had magnitude six quakes but more severe ones could be possible." Azula told Katara. "In the event of such an event, the challenge will be getting back up and running. The safety features in the systems are designed to prevent damage or reduce it to repairable levels. Of course, most people want to know if the reactor could explode – no. Could it leak fuel – no. Could it leak coolant, perhaps but one of the advantages of carbon dioxide is that it holds little radioactivity."
Karo had training in operating the fueling robot. Azula trusted him because he was fussy and his gorgeous technical drawings revealed a delicate touch. He had great patience which the refueling system demanded. Azula hated that machine and cursed it for being slow, clunky and trying her limited funds of patience.
"How nice to see you Katara." Karo sat up from his workstation and bowed.
"May I say its nice to see you." Katara hugged Karo. "I never thought you'd be working here."
"I get paid well." Karo grinned and sat down in his chair. "I have the kind of patience for this work."
"What do you do?" Katara asked as he took hold of a large steering wheel.
"I have the job of supervising the fueling the reactor once we receive the full fuel load." Karo adjusted his controls. "This fueling crane will eventually service Reactor One and Two. Right now I'm seeing how it performs but I'll have the job of training the technicians once they arrive."
"How does fueling work?" Katara sked.
Karo sat back down and stared out the tiny window of meter thick glass. He had a thick window to view the reactor core and a set of lights on the wall in a circle had a pattern of green and white lights that made sense to him. He had designed most of the indicators and displays in the plant and this one showed the geometry of the core along with indications as to whether the fuel channels had fuel.
Azula immediately stepped in to answer. She had noticed distracting Karo while he ran the crane often caused him to drive the massive machine into the concrete walls of the reactor building. This made the kind of thud that scared the living daylights out of everyone else in earshotbut as the crane could lose a race against the slowest snail, did no damage.
"The fuel consists of uranium in shiny metal jackets." She decided against insulting Katara's intelligence. "Karo can you move over?"
Karo complied.
"If you look through the window you'll see manhole sized covers." Azula sat Katara down in the seat.
"Yes...okay." Katara peered through a yellowish tinted window.
"They are the fuel channels." Azula said pedantically. "When we fuel, eight fuel rods are loaded into the loading chamber off to the side. You can see the heavy door?"
Katara nodded.
"The fuel rods are placed outside that."
"The crane picks up the fuel rod and Karo guides it to the channel to be fueled." Azula announced. "When he has aligned the crane, he lowers it and the crane come to rest over the fuel channel. Karo then slides the cover to the side and the channel is open and he lowers the fuel into the reactor on a grapple."
"What if he missed?" Katara asked because she had begun to wonder how anyone could make sense of the dim yellow view of the plant innards the windows offered.
"The covers have alignment marks and the crane mechanism has shielding." Azula told Katara. "The result if he misses is a loud bump."
"What if you take out fuel?" Katara again asked. "You must have to deal with hot gas and the radioactivity from the fuel?"
"The crane has a design to hold that all in." Azula explained. "Did you actually read my papers?"
Clang!
Katara jumped and grabbed her chest.
Azula slapped Karo across the top of the head.
"How can you not see that?" Azula scolded. "You hit the wall! The wall!"
"When you asked me to do this..." Karo grabbed the wheel hesitantly, "didn't you ask me 'to play hob with the reactor internals'? We want to see what breaks and fix it because then we won't have any surprises." Karo resumed his work. "I feel like a lumberjack attempting brain surgery with an ax."
Azula merely played at scolding Karo. The crane made loud noises at the slightest occasion. Karo hadn't actually hit anything: the bang happened when the crane reached the forward limit of its travel. The fueling crane was a yellow behemoth that Karo controlled with a very delicate touch. The crane wasn't delicate or fast and barely seemed to move at all. With a nuclear payload, abrupt movements violated any notions of safety. The fuel handling portion of the crane consisted of a hexagonal shaped stubby pencil like device dangling off pulleys and a set of thick cables. The fuel handler itself weighed many tons, stood a story high and was at least a meter and a half in diameter. Most of the massive weight came from the shielding put in place to protect the operator from the searing radioactivity of spent fuel.
The fuel bundles were individually packed in wooden crates. They stood over two meters tall and looked as shiny as fine silver. At the top, a set of machined grooves allows the crane grapple to hold on as it moved the fuel. The fuel pins were welded to the thick central hub in a circle. The outer circle had twenty fuel pins, the inner had twelve.
Katara watched the workers in the fuel warehouse unpack the fuel rods. The crates sat in shallow wells in the floor. A worker tore the top off the wooden crate with a pry bar. The warehouse crane operator lowered the crane over the top of the rod and a clamp grabbed it with a grapple that then closed around a metal knob at the top. He lifted it up, then moved it over to a truck which had metal holders that held the fuel rods. Each holder held ten fuel rods and when filled up the truck drove through a heavy garage door in the side of the reactor building and onto a platform that had a forklift like machine that lifted his bin of fuel rods up to the reactor fueling door. This door was the thing bank robbers dreamed of in their nightmares. The five meter thick door opened and the crane picked up the fuel rods.
Katara accompanied Azula on her inspection of the fuel rods. Azula held out a magnifying glass and bright gas lantern with a lens to focus the light.
"Aren't these fuel rods radioactive?" Katara asked Azula as Azula bent over and rubbed her hand over a weld that held the support plate to the inner and outer fuel rods.
"Natural uranium fuel is only slightly radioactive and the fuel rod cladding will protect us." Azula ran her hands and the light down each tube.
Katara still wondered.
"What do you need to inspect them for?" Katara had a job. She had to ask about the operations of the place so she felt at liberty to ask.
"They weigh a lot so a bad weld could spell trouble." Azula ran her hand back up the rods. "We don't want to have the rods jam while fueling because then we'd need to have to take them apart – more time and more cost. We don't like to have the rods open in the reactor because then that could make the carbon dioxide radioactive. Again, more downtime, more cost." She paused and reached for a pencil behind her ear. "We'd have to release the coolant gas into the atmosphere and remove the defective fuel rod. Why not take the time now and do it right – eh?"
"Isn't that dangerous?" Katara had her doubts. Azula treated radiation like a natural phenomenon but the reactor had been built to keep something ferocious prisoner.
"Not really." Azula waved at the crane operator.
The metal cage he sat in slowly rode out along a track humming and clanking.
"I chose carbon dioxide because it doesn't hold much radioactivity and so we can purge it and yet no one will be affected." Azula eyed Katara. "You can breathe out now." She patted Katara on the back. "Why are you so nervous here?"
Katara did a small dance and nothing happened.
"I can't water bend." She told Azula reluctantly. "I can sense water under the plant but I can't water bend."
"Once you leave, your bending will be as it was. We think that water bending doesn't work very well here because of beta decay. You're close to a nuclear reactor and in a fuel storage facility full of uranium." Azula waved an okay to the crane operator who controlled the fuel transport. "An atom of uranium or any radioactive material spits off an electron from time to time. Harmless to us but we think your bending keys off the single electron of the hydrogen atoms in water and the free ones kicking around here might absorb that power. We have theories but no firm answers."
Katara balked.
"In any event, some of the machines we have do not react well to water bending." Azula continued in her pedantic way. "No type of bending works well in the vicinity of a nuclear reactor. We discovered this quite by accident when we began to tinker with our experimental reactor and no one could bend. We think the extra neutrons produced during the fission process block earth bending and the presence of high energy gamma rays fouls up fire bending. We have no idea whether this place can have an effect on air bending. I admit this is all just conjecture."
Two idealistic, young men and two women had climbed the tall stack using the maintenance ladders on the side. The tower had a small elevator which technicians used and since the control box was locked and the key sat in a drawer at Karo's desk with copies in the hands of technicians – this hinted they were not staff. The stack looked tall and slender but had a diameter of eight meters and the protesters had begun to unfurl a large banner when Azula and several senior engineers ran out following Karo.
"Does the plant have its own circus high wire act?" Karo pointed up at the lip of the stack.
Azula trained a set of binoculars on the climbers. She saw four of them at work on some kind of civil disobedience.
"Nuclear physicists build nuclear reactors; we don't like taking risks with our safety." Azula popped the leather covers off of the eyepieces of her binoculars
"We have a Water Tribe infestation." Azula explained to Karo.
"The weather has been damp and cloudy as of late. Maybe that brought them out?" Karo looked up at the colorfully dressed protestors. "Why would anyone want to climb up that thing?"
"Last week, I had a talk with our accountant about hiring on a security detail." Azula watched the action in the skies above Chameleon Bay as the protestors struggled to control the banner in the high winds. "He told me the company didn't think we need one right now because we're so remote."
"Come on Karo." Azula grabbed his collar. "We're going to have a talk with out intruders."
"I went to the top of that thing once because you wanted to show me the view." Karo sulked. "You took me up in a rickety looking elevator which looked like something window washers wouldn't use. You didn't warn me the stack swayed in the wind either."
"Maybe they're suicidal and gregarious." Karo added reluctantly
"What does that mean?" Azula walked out onto a metal walkway that led across the concrete roof to the stack.
"A group suicide pact?" Karo followed behind Azula. "What better place to jump from – none of that slim chance of survival worry – I remind you we have an asylum in the area."
"Falling bodies pose a safety hazard and our union would kick up a fuss if someone took an errant flailing suicidal maniac in the head." Azula fiddled with a ring of keys and pushed open the red door that led to the roof and both of them emerged on a metal walkway that led to the stack. "Look at all this lovely pre – stressed concrete – imagine getting a blood stain out of it. I doubt if environmental protestor would hang a banner and then leap to their deaths: they want to make a point, shut us down and live in a world free of incandescent light.
"We'd get hit first." Karo said darkly.
Azula looked up through her binoculars.
"You intend to talk to them?" Karo said in trepidation.
Azula waved her large keyring. "Aside from my skills as a nuclear physicist, I happen to take an interest in psychology." She pulled out a key and opened a metal cage on the wall. She pushed a mushroom shaped red button and a siren went off.
"You've inspired others to take an interest in yours..." Karo mumbled.
"What was that?" Azula jingled the keys.
She looked up at the four people on her tower. "Get a job!"
A boom swiveled out and a metal basket began to slowly head toward them.
"Get a job!" Azula yelled out. "What to you want!? Choking pollution or clean energy!"
Karo had a more pragmatic approach. "While I feel put out because the morning is damp and I enjoy manning that desk; do you have plans for what to do once we meet these people? As they have clearly got the higher ground, can we really do anything?"
A lute fell and made a pathetic twang and loud crackling smash as it hit the roof.
"They have lutes." Karo jumped back.
"Can I ask what business you have with us?" Azula shouted between cupped hands. "You do realize that you're trespassing!"
"Who are you?" A woman's voice answered back.
Karo watched the basket descend down the stack.
"I am the head engineer at this facility." She shouted back. "Not a luthier in case you may need one." Azula barked out threateningly and then held up the broken lute.
The metal cage slowly descended on thick cables and hit the ground with a soft clunk.
At the same time, the sirens on the top of the stack sounded off. A long banner fluttered to the ground.
"What!?" Karo asked as he stood behind the desk with Azula and wondered if the ringing in his ears would ever quit or if he'd never know for sure if it was him or the phone ringing.
"I wasn't talking to you!" Azula yelled as she paced in front of the four protesters. They were an older man and a woman and two younger adults about her age. "I didn't think of sounding the 'radiation release horns' but their one hundred and twenty decibel wail did bring you down from up our stack."
"What!?" A tall lady with lavender flowers in her hair shouted. She had the clothing of someone from the Northern Water Tribe and looked lithe and athletic. "As defenders of the traditions of The Northern Water Tribe, we demand to see our lawyers."
"What have your traditions got to do with our stack!?" Azula found herself yelling over the ringing in her ears.
"You have no security on site – did you know how easily we sneaked into this place?" The lady shouted back and wondered if she needed to see a doctor or healer to check for bleeding from her ears. She had heard loud sounds but the plant sirens had gone off a few meters over her head and out of fear for having her and her companions either deafened or fried (if the siren signaled a radioactive release) she came down.
"What will they steal!?" Azula stuck her finger in her ear. "You do know most of the things around here are either bolted to the ground or weigh many tons? I don't think our refueling crane will turn up in a crooked pawn shop in Omashu."
"The pen keeps getting stolen of my desk." Karo said loudly and sat behind the lobby desk made of gray polished concrete as if seeking its bulky security. We have a security guard at the end of our road and a chain link fence around the site. You had to climb over a two meter fence and sneak through the oak forest with this." Karo lifted up the corner of a huge cloth banner that read 'Chameleon Bay Kills Unagi!' painted with great skill using dark blue characters on a white background. "The banner is very nice work."
"Lets begin with who you four actually are!" Azula glared at Karo and grabbed the huge banner off the front lobby desk. "The banner claims we kill Unagi. Isn't that some kind of deep sea serpent of the Southern Oceans?"
"Places like this threaten our way of life," a man with a bald head, older and stouter around the tum than the woman pleaded, "and our village selected our family to take the message to you directly."
"Places like this?" Azula leaned on the desk and gave the man a puzzled look. "We're the only operating nuclear power plant in the world." Azula had to hold back her tongue. "Karo, have you called the authorities to retrieve these four?"
Karo already had called the local police. "Yes...they're on their way."
"So this is it, we're going to face imprisonment?" A tall young woman said sadly as she placed her hands gently on the older lady.
"Trespass and public mischief aren't serious offenses." Azula had her hands behind her back which always reminded Karo of the mannerisms of a put out hen. "The National Electric Co - op owns this place and I suppose they'll decide whether to press charges. You'll face a fine, maybe a few hours of community service and then slip out of Chameleon Bay in a favorable wind and never pay the fine or paint the light posts in the park or whatever."
Azula stood out on the sea wall built down the hill from the plant. Warm sea water discharged into the pool made by the two arms of the sea wall buffering local marine life from the effects of the lukewarm water used to cool the steam condensers. A damp wind blew from the sea.
Spring had arrived reluctantly and it had remained cold and damp the past week.
At high tide, the sea wall stood about four meters high, she knew it was low tide because she could see the slimy, green outlines of the granite blocks dropped in place to secure the concrete deck of the sea wall. She could see three local men fishing off the leeward edge of the wall (the wall was public property) which made her wonder if warming the water might actually have improved fishing.
She looked back on the plant. It dominated the landscape as it stood on a hundred and fifty meter tall granite bluff like an industrial age castle. She held out the probe of a Geiger Counter.
Nothing above background radiation levels turned up.
'Would people have such a problem with this place if I weren't a woman?' Azula waved the probe in the air. The granite of Chameleon Bay had its own natural level of radioactivity. The same granite made the plant possible because it made for sure footings, but made it hard to construct because the sea water system had to run through it.
Azula had moments of self doubt, but to men, she always proceeded with total confidence and expressed her doubts and lack of confidence only to Karo. She looked at the plant. The future could never be foretold and some calamity could destroy much of the plant during the planned six decades of planned use. Steam boilers did explode and kill people, turbines could blow apart and people could find themselves as ground in some electrical mishap. Such accidents happened in coal plants.
Azula turned around at the lighthouse at the end of the sea wall and turned around. The wind had begun to kick up.
Oddly enough, she didn't fret about the reactor safety systems. The power plant had all sorts of emergency valves and steam handling equipment in the event of steam accidents and lots of electrical safety features to prevent fires and death. The power plant had four diesel generators to provide light and power in the event the plant lost power due to natural disasters like an earthquake or typhoon. Azula had no faith in safety system designs. She decided to rely on sturdy construction, thermal expansion, convection and gravity to save the situation if something went badly wrong. Those funding the project agreed with Azula that a simple machine didn't stand as much of a chance of going south as a complex one. They also decided simplicity of design did much for the bottom line.
The Avatar found himself appalled at this attitude. He didn't care for 'implementation simplicity' or Azula's argument against complex safety systems. She argued with impeccable logic that she didn't intend to build a reactor that had to be told to shut off by some system. She wanted it to shut off because when something went wrong, continued operation under any circumstance was simply impossibleii.
He saw Karo and the senior reactor operator, Doctor Piangdao approaching her.
"We had a 'burst can alarm'." He explained as he stroked his goatee.
Azula had expected this sort of thing and wasn't a problem. The term 'burst can' referred to a fuel bundle that had either overheated or had a fabrication defect. The fuel rods sat on a metal post with a powerful spring in a piston at the base. If the fuel rod overheated, solder melted and freed the spring and pushed the fuel up out of the reactor where the refueling machine removed it and refueled it with a known good unit. Such a system removed the rod from the graphite and since no further fission could take place outside of the core, it allowed it to cool. Fuel fabricators tried to meet specifications and yet despite inspections, she knew a few bad rods might enter the core.
"We'll take the fuel rod out tomorrow and treat it as a rehearsal." Azula made a few calculations, "Brief the refueling operators that we'll take our time and replace the bundle next week."
"Will we go offline?" Piangdao asked.
"Is the fuel rod mechanically sound?" Azula asked.
"It reached the top of the fuel channel so yes." Piangdao answered confidently. "It popped the red flag on top and so we're not expecting mechanical problems. Nothing in the temperatures indicated an overheat so this looks like a bad fuel rod."
"I'll have a look." Azula walked with them back to the main road. "Once I'm satisfied, we'll use the standard procedure and leave the reactor up." Azula had good reason for this. She had designed the reactor to be fueled while under power as it kept the plant online without the headaches of a cold shutdown: the reactor didn't like being on. When turned off, the fuel poisoned itself with decay products that inhibited fission. The vast surface area of the fuel rods, the huge volume of gas and the mass of graphite meant the core had little latent heat. If left in shutdown for a few days, the convection across this vast surface area by the carbon dioxide would cool the core and shed the latent heat in the fuel and after a day the core had a mean temperature of less than the boiling point of water – useless for power plants. The start-up meant waiting for the poison to decay – at least a day, and a long pre – heating period of three days to get heat into the core and coolant gas.
While no one could enter the reactor, workers had access to the top of it. The reactor looked something like a beer can in shape, with the top 'floor' having heavy steel doors and a thick roof and the clutter of shiny metal machinery, ports, and parts made it hard to navigate.
Azula walked across the landscape of shining, gleaming metal circles, stubby pipes and chrome fittings. Karo always found it hard to keep his balance on the reactor lid because while the designers made it accessible, the chrome fittings always managed to trip him up. He found it particularly hard to keep himself from tripping because he had to hold the schematic which diagrammed the top of the reactor, the control rod motors, fitting and the large round shiny fittings for loading fuel. The reactor had 128 fuel rods and so the top of the chases had shiny metal loading plugs numbered 0 to 127 and they had to hunt down number 56 which had gone bad.
Azula had to know the exact location of the bad fuel rod so she could guide the crane operators onto it. Offloading fuel rods while the reactor saved time but meant a complex series of operations had to take place. The crane had to land over the correct fuel plug and connect with the three sturdy steel fittings sticking up from them – the ones that kept tripping up Karo. The crane operator had to fill the inside of the crane – a hollow chamber lined with dense steel – with reactor gas. Only when properly pressurized and correctly filled could they lift out the plug, move it to one side and extract the bad fuel rod with a heavy grapple.
"Found it." Azula pointed to a red flag like a mail box flap that had risen out of the floor. "Mark it off on your map."
Karo looked down and made a mark on the map. He had handled the fuel crane and so had the task of supervising the operation. The same operation would take place thousands of times in the life of the plant. The crane would remove spent fuel and ferry it to the spent fuel silo between the two reactor unit on this side of the plant and then deposit it in a spent fuel cask built to hold the fuel rods in such a way carbon dioxide could flow through it. Once plugged and sealed in the cask, the fuel could sit a year or so until the cask had filled up and then hauled off to be deposited in a concrete vault in a man made cave propose built on the site.
Karo didn't have to worry about the fate of the fuel at that point. The plant had a planned life of sixty years; the vault could serve for that length of time. After it had served its purpose, the plant would close and the vault would then be entombed in concrete and left forever.
Azula had a small periscope like probe inserted in a dedicated port in the reactor platform dedicated for the purpose of inspecting the reactor core and innards. The device contained a clear, dense liquid that absorbed radiation but like the viewing windows, allowed light through and so the observer could inspect the reactor innards without harm. The fuel tube was made of a shining corrosion proof steel alloy – expensive but intended to last a lifetime. The fuel rod looked like a circle of small silver pipes all welded together to a central rod and it looked as shiny as every other piece of metal in the reactor.
Before removing the fuel rod, she decided to take a look at it. At least if it had gone bad, she could figure out how it had gone bad before they removed it.
Next to her, neatly arranged in a row were a series of odd looking but very shiny tools.
Karo sat on the floor of the charge platform between the metal fittings and had drawings out. Next to him sat two red metal boxes; one contained tools, the other had held the periscope.
"Aren't we overdue for another group of idiotic protesters to hang banners." Azula peered through the eyepiece. "I can't see any evidence of damage to the core so I suppose we're a go for refuelling."
Azula had concerns about the integrity of the reactor innards given that a new fuel rod had tripped off in a manner that suggested an overheating problem.
Karo had done the technical drawings for the reactor core and he had the large map of the graphite blocks of the core. The core consisted of a series of metal stringers on which the fuel tubes, control rod tubes, cooling vents and graphite hung. Geometry mattered in this arrangement as the mechanical tolerances allowed fuel rods and control rods to move up and down in their channels. Each graphite block had keyed bits like landscaping blocks that allowed them to fit together properly and the whole assembly fit snugly together.
"The fuel rod looks intact..." Azula had a note of bewilderment in her voice. She pushed the periscope further down. Azula had assured the Avatar that her nuclear power reactor could not fail catastrophically. She had supervised every detail of its construction so even a small failure made her doubt her capabilities.
Azula tapped her lip and thought. "I wonder what would happen if we reset the rod?"
"We should have it trip off in a few hours when it overheats." Karo explained as he looked at the blueprints. "You don't think its defective?"
"It's a very expensive fuel rod," Azula stood up and rubbed her eyes, "I don't want to write it off because of a bad trip or a one time, momentary glitch."
Azula uncoupled her eyepiece. She picked up a special tool that looked like a wrench with a cross piece with rubber handles. She fit it on the end of the rod she had used for viewing and turned it an exact number of times. She stood back as the pressure of the hot gas in the reactor slowly pushed it out of the reactor. She picked another tool shaped like a meter long bar with a crescent wrench hex fitting in the middle. She turned it slowly until she heard a metallic click.
Karo had never heard anyone compliment him on his own brand of ingenuity but he had to take the award for extreme cleverness in designing the tools and mechanical systems in use in the reactor. He had taken top of his class in mechanical engineering. The mechanical systems and hydraulics had come out of his head. The reason looking into the reactor didn't fry Azula had come out of his work. He had taken a tube of stainless steel and made the working part of a periscope and machined it into two halves. He filled it with zinc bromide so the light could penetrate but the radiation couldn't. One half of the thing sent light from a torch in the eyepiece down, the other half had mirrors that sent the light to the magnifier and on to the person at the other end. The bottom had a set of reverse thread to lock into a plug in the floor of the platform. With a special tool, the plug allowed itself to descend at the bottom the periscope and also locked it back in place when it came back up..
Karo felt the heat wafting off the periscope. They'd leave it to cool off.
She pushed down on the red flag. A small pulse of hydraulic fluid sent a message to a ram to push down on the fuel rod against the force of the spring and push it back below the charge face. Azula knew her reactor system and a set of loud clicks meant the rod had reset itself in the reactor. She listened for a loud metallic thunk but none came. A loud bang meant the rod had shot back out of the reactor and hit the underside of the platform plug in the lid of the reactor.
"Tell me again what took place on the night shift?" Azula marched along a pipe chase.
"A sluice gate jammed closed in one of the seawater condensers." Karo held a clipboard as Azula wandered along a steam pipe. "This happened last night at one thirty in the morning." He followed Azula. "Odd but not dangerous. Sea water temperatures spiked but the sluice began working a half hour later."
"How far above tolerance did it spike?" Azula looked up at the face of the concrete chamber that held one of the two boilers.
"It reached ninety degrees briefly, sixty above the limit we are allowed to discharge. Boiler One briefly cycled only steam until the pressure water injectors refilled the heat exchanger. The turbines show no damage." Karo looked at the report. "We have a crew looking into it."
Azula ran her hand along a metal covered wiring duct to check it temperature. It felt cold to the touch and to her this meant no faults.
"We probably ingested a log." Azula told Karo. "Make a note and have the crew check for debris – then check the grates over the intakes and outlets."
"Should we be concerned?" Karo jotted the note down on his clipboard.
"I haven't seen any signs of a problem – a fuel rod trips, yet now its fine." Azula wore a look of concern. "They say bad luck comes in threes? We had anomalous readings from half a dozen instruments. Remember all the pyrometers in the core pegged themselves at the high end of their scale, then came back – a fault in the wiring board. The sluice gate system has started acting up but we've had no safety issues so the reactor is sound."
Azula inspected a simple pressure gauge on the side of the boiler. It read correctly.
Karo had a checklist he used on inspection and checked off that item.
"I gather a report has gone off to headquarters?" Azula walked over the steam pipes. "Or are you waiting for the inspection crews to report back?"
"I don't like bothering with reports until I have something to report." Karo carefully stepped over the steam pipes as if they were landmines. He knew nothing short of a bomb could breach them and yet he hesitated to step on them. "I could file a report about last night and they'd ignore it because it didn't cost anything to fix. Why waste time on something that will sit on a desk in the Ba Sing Se headquarters? The NEC loves reliable, cheap and clean power but hates controversy. We began operations to the sound of no publicity at all – a small two paragraph article on the back of the science page stated that 'we began operating Unit One but won't officially open until all four reactor units are online.'
"The King hates to travel." Azula said bluntly. "The NEC also want to keep things quiet lest The Avatar kick up a fuss. At least The Avatar and Zuko are busy with that fool idea of setting up a republic in the western part of the Earth Kingdom. Who knows? The capitol of their republic needs electric power and so maybe will buy a reactor unit or two." She glanced up at the dome of the roof. "We're partly a sales team – imagine that."
A loud crash and the sound of trees snapping greeted Karo as he placed his pencils in order on his desk.
"Did Reactor Unit Two blow up?" He asked himself as Azula rushed towards him accompanied by Piangdao. "Will we find a technician impaled on a control rod with five hundred tons of graphite scattered in the flaming woods?"
"If a reactor blew out, you'd be dead by now!" Azula grabbed Karo by the collar. "Something crashed in the woods!"
Karo rushed through the doors and out past the parking lot.
What they saw made them gape.
"Badger moles!" Piangdao cried out. "Dozens of them."
Azula could hear the sound of splintering wood, the scraping of rock and the ounds of panicked creatures. She had not planned for this contingency: the nuclear plant blocked all bending. She had thought this a security feature that provided a much needed level of safety. She realized suddenly that this need not be so. Badger moles by their nature relied on earth bending and now had run amok because they had gone 'blind' and in their confusion, had found themselves confused and bewildered on the surface.
"What do we do!?" Piangdao asked as he watched one mole uproot a tree just behind the substation.
"You head inside and strike up the siren!" Azula commanded. "I hope the noise with scatter them or drive them away before they blunder into anything vital – go!"
Piangdao ran back inside.
"If they stumble into the substation..." Karo warned.
Azula cringed and shook her head as she watched another large oak tree fall. The substation delivered the output of the plant to the outside world and also contained the trio of emergency diesel power generators. A badger mole unfortunate enough to break through the concrete wall protecting it, had no chance of surviving the half a gigawatt of power running through it but he might also destroy the substation in his death throws.
"Blundering around the catacombs of this place with torches for weeks doesn't appeal to me." Azula quietly hissed in frustration. "We had a few environmental survey – we have no badger moles for hundred of clicks."
Azula had no idea who had built that siren but it could split eardrums for leagues around the site. The badger moles rushed away from the horrid noise, crushing trees and once they could bend, tunneled away leaving a cloud of dust in their wake.
Notes
iThe bottom of the GGR reactor had a complex network of piping that radiates outward to a central vein. The metalwork Karo designed used color coded pipes that when installed looked like the patterns seen in a cherry blossom and so the name stuck. The AGR borrowed many design concepts and also had beautiful looking plumbing. Karo's mechanical designs in the AGR also proved equally beautifully and finely crafted. Karo had decided to trust natue and used natural forces like temperature and gravity to make the reactor safe. He never doubted that fission was a natural force – after all the core of the earth used it to make life possible.
iiIt is possible to do this. When Azula speaks of a 'core' in an AGR, she means a set of fuel loading tubes. Each tube projects out of the graphite core block, through the concrete charge face and then through the upper chamber where hot gas flows out of the reactor and through into the loading chamber. Fuel tubes are made of strong steel alloy but they are thin walled and thus are cheap to make. The AGR has no pressure vessel but the works including the boilers sit in a steel lined concrete vault. Unlike the Fukushima boiling water reactors (BWR), the AGR has no need of a pressure vessel as carbon dioxide is heavy, easy to contain and incapable of producing explosive steam or hydrogen gas.
Such a core can't melt down. Graphite can tolerate more heat than tungsten. The reactor in shut down mode relies on passive convection to rid itself of latent heat and the heat exchangers can use either water or air and the tunnels under the plant allow for the use of both. As the 'core' has a volume of solid graphite twenty time larger than the core of a typical BWR, heat can escape through a much vaster area. The AGR also has no active safety systems: convection alone cools it and should the fuel heat up, a spring loaded mechanism pushes sections of the fuel rod apart to increase surface area and shut off the reaction. Gravity operated 'poison' systems will drop control rods into the reactor if power fails and shut it down. Azula objected to containment structures beyond that of the reactor itself. She didn't approve of the construction of large domes over the reactor and heat exchangers and in fact the domes are not hermetically sealed due to steam pipes and the tunnel network used for cooling the turbine steam and air cooling systems.