TRAGEDY AT FUKUSHIMA DAIICHI

"HEAT SINK: a small metallic device attached to your CPU that, like the cooling tower at a nuclear-power plant, is the only device standing between safe, reliable system operation and a total core meltdown.”

—Howard Johnson, Ph. D., in Manager’s Guide to Digital Design

It would be difficult to think of a worse place to build a nuclear power plant. Perfectly safe nuclear generating stations have been built in hazardous locations from Antarctica to the Greenland glacier, but putting one on the beach in Japan, looking out over the ocean, right there on the Pacific Ring of Fire, seems ill-advised. The Ring of Fire, encircling the entire Pacific basin, including the California coast, is under constant threat of earthquakes, tsunami waves, and volcanoes from the westward tectonic shifting of the North and South American continents.

The nuclear engineers, mechanical engineers, civil engineers, electrical engineers, and seismic specialists in Japan are well trained and experienced, and they know how to optimize a building project. That is why, for the 54 nuclear reactors that were recently generating 40 percent of the electrical power in Japan, there is not one cooling tower. Why build natural-draft, fog-making, hyperboloid cooling towers, 600 feet tall, when you can use the Pacific Ocean as the ultimate heat sink for your generating plant? It saves a lot of space, which is precious in Japan, a lot of concrete, construction time, and money.

Every nuclear plant in Japan is built on the coast. Those in the southwest of the main island of Japan, Honshu, where the electricity alternates at 60 hertz, stare into the Sea of Japan. Those plants in the northeast of Japan, where the electricity alternates at 50 hertz, overlook the subduction zone where the Pacific tectonic plate runs underneath the Okhotsk tectonic

plate.257 As the North American continent glides westward on the slippery, molten rock on which it sits, the Pacific Ocean gets smaller and smaller, the Atlantic Ocean gets bigger and bigger, and the Pacific Plate subducts under Japan at a blistering 3.6 inches per year. It is not a smooth movement. The Pacific Plate sticks to the Okhotsk as it tries to fold under, and it can hang, not moving, for a thousand years as the tension builds up. Finally, the situation between the plates is stressed to the breaking point, and it just lets go, all of a sudden, in the rocky depths miles below the bottom of the ocean off the coast of Japan.

The shock wave produced by this abrupt movement travels fast through the rock, and it hits the Japanese islands with more force than any atomic bomb could produce. Things sticking up out of the ground are sheared off as the Earth underneath suddenly shifts position by

measurable feet. Destruction is widespread as the entire island shakes.

Moving more slowly, the second shock wave moves as an enormous ripple in the ocean water, beginning over the point undersea where the plates slipped and moving in a circle of growing radius. As the ripple nears the shore, the water gets shallow, and the shock wave, distributed evenly in the liquid, gets funneled down and concentrated. The amount of energy is still there, but there is less and less fluid to hold it. The ripple becomes a monster wave, and it hits the shore as a wall of water, the tsunami, coming very fast. It finishes off anything that was not knocked down by the initial shock wave through the ground and inundates inland territory.

That is why there are better places to build a nuclear power plant than on the beach in Japan, which would seem evident from the remains of what was once a roughly semicircular pattern of ancient, inscribed rocks, planted upright in the ground a few miles from the shoreline in northeastern Japan. These monoliths, probably 600 years old, are all graven with the same message, written in a long-forgotten Asian dialect. Scholars pooled resources for centuries, trying to decipher the message, seeing success some 30 years ago. Very roughly translated, the inscription reads: “Don’t even think about building anything between here and the ocean.” A thin layer of water-borne silt underneath the topsoil, ending about where the stones are placed,

attests to the fact that a tsunami wave once washed this far inland.258

The secondary cooling in a Japanese reactor is breathtakingly simple. A concrete pipe extends for a couple of hundred feet out into the ocean from a pump stand on the beach. A screen keeps curious sea life from being drawn into the cooling process. Water is sucked in by the pump, circulated through the condenser in the floor under the steam turbine, and introduced back into the ocean at a point a few hundred feet farther up the coast. A cooling system could not be any less expensive to build.

The quest for nuclear power in Japan began in 1951. The centralized state-run power company, established for national wartime mobilization in the last Great War, was formally dissolved, and nine small power companies were formed. One was the Tokyo Electric Power Company, Incorporated, now known as TEPCO, formed on May 1, 1951. Its territory was the upper eastern section of Honshu, the main island, operating on 60 hertz current.

There were never a lot of burnable resources in Japan, so generating power using steam was challenging. Liquid natural gas and fuel oil had to be imported, and this was not only polluting the air, it was extremely costly. Despite resistance from atomic bomb survivors, Japan would have to “make a deal with the devil” and embrace nuclear fission if it was to compete in the industrial world. Construction on the first plant, a British Magnox graphite pile, was begun by the Japan Atomic Power Company (JAPC) on March 1, 1961. They put it at Tokai, halfway down the east coast, and it had no cooling towers. The race to provide Japan with nuclear power was on.

TEPCO began its part of the nuclear expansion with the Fukushima I Power plant. Construction began on a single General Electric BWR/3 reactor with a Mark I containment on July 25, 1967. It would be the first of six boiling-water reactors built on the same property in the small towns of Okuma and Futaba in the Fukushima Prefecture, and it would become one of the world’s biggest nuclear power facilities. With everything running simultaneously, it could produce 4.7 billion watts of electricity. A second plant, Fukushima II, was built a few miles down the coast, and, by the turn of the 21st century, two more GE BWRs were planned for

Fukushima I. Unit 1, the first completed reactor in the new plant, was switched into the power grid on March 26, 1971.

At the time, General Electric was competing vigorously with Westinghouse for the hearts and minds of nuclear power-plant consumers, and the goal was to make the most economical plant with the least accident potential. Westinghouse was pushing their upscaled version of Rickover’s flawless submarine engine, and GE was hooked on Untermyer’s dead-simple BWR. To optimize these designs for the civilian market, there were several engineering modifications to make.

The Westinghouse reactor is comparatively small, and neutron flux is controlled by a concentration of boric acid in the coolant. Secondary protection from fission-product escape into the environment is a thick concrete building constructed around the reactor. As was demonstrated at Three Mile Island in 1979, the building is strong enough to withstand a hydrogen explosion inside.

The GE reactor had to be big and tall, about 60 feet high, because the engineers had simplified the structure to include the steam separators and dryers in the top of the reactor vessel. To use external separators would involve a lot of complicated plumbing, and an

engineering goal for these civilian reactors was to minimize the pipes.259 The separators and dryers kept water droplets, which could quickly destroy a steam turbine, out of the steam pipes. The resulting integrated reactor/separator vessel, made of six-inch steel, was so tall, there was no way to construct a sealed, reinforced concrete building around it thick enough to contain a possible steam explosion. There would be a stout, rectangular structure covering the reactor, the refueling pool, and the traveling crane above, but it could not be specified as pressure-tight.

Not having a separate building as the secondary containment structure meant that something else would have to encapsulate the reactor vessel, so a large pressure-resistant container with a bolt-down lid, made of inch-thick steel, was designed to be built around the reactor. This “dry well” is shaped like an inverted light bulb, being a vertical cylinder surrounding the reactor with a spherical bulge at the bottom. The dry well is supported off the floor of the reactor building by a large concrete pillar.

In a Westinghouse reactor, a steam explosion due to a major pipe rupture is controlled by letting the steam expand into the building that houses it without letting the steam breach the walls. The steam has enough room to dissipate its explosive energy in the process and condense into water, which runs down the inside walls and into the sump. With this arrangement, no fission products dissolved in the steam are able to contaminate the countryside. Under extreme conditions, overpressure from steam trips a relief valve and it goes up the vent stack. In this worst case, radioactive steam is released, but the building remains intact and able to contain further contamination.

The dry well is not of sufficient size to contain such a steam explosion. To deal with this maximum accident, there are eight large pipes connected to the spherical bulge and pointed down. Circling the reactor at the bottom of the dry well is the “wet well,” which is a large torus or a doughnut-shaped steel tank, 140 feet in outside diameter, into which the connecting pipes terminate. The doughnut-tube is 30 feet in diameter, or slightly larger than the pressure hull of an early nuclear submarine.

This wet well is half filled with water, 15 feet deep, and it is held off the floor by steel supports. In the event of a sudden high-pressure steam release, the hot gas rushes down the eight pipes and blows out under water in the torus. This tames the steam by cooling it. It condenses into water, which is then pumped back into the reactor vessel to keep the fuel from melting. The GE invention, the Mark I containment structure, is thus able to do in a relatively small space what a Westinghouse reactor needs an entire building to accomplish.

It seemed an exceedingly clever workaround for the problem of otherwise needing an impossibly large reactor building, but the General Electric Mark I containment turned out to be the most controversial engineered object in the 20th century. Disagreements of an academic nature concerning the design may have been flying around at GE for a few years, but the problems became semi-public at a “reactor meeting” in Karlsruhe, Germany, on April 10, 1973, when a paper was presented by O. Voigt and E. Koch, “Incident in the Wuergassen Nuclear Power Plant.”

Wuergassen was the first commercial reactor built in Germany, on the River Wesser between Bad Karlshafen and Beverungen. It was an early BWR/3 with a Mark I containment. The Germans had spent four years building the plant, and they connected it into the power

distribution system in December 1971.260 They were aware of rumblings of possible discontent concerning the Mark I containment coming from many directions, and they decided to put the speculations to rest by performing a simple test. Responsible engineers at GE claimed that the Mark I “did not take into account the dynamic loads that could be experienced with a loss of coolant.” It was great design on paper, and it looked wonderful standing still in the basement of the reactor building, but would the steel torus stand up to live steam being suddenly blown down into it, or would it experience transient forces for which it was not prepared? The Germans ran the reactor up to power, making a good head of steam, and then sprang all eight steam-relief valves open at the same time.

Behavior of the torus under this “worst case” condition had not been predicted by even its strongest detractors. It quenched the steam under the water in the half-filled torus as it was supposed to, but not thoroughly, and the steam started to swap sides, first showing up on the north side of the torus, and then on the south side. The torus became possessed by “condensation oscillation,” and it started rocking, tearing the support irons out of the floor and terrifying the reactor operators. It finally settled down, but not before causing expensive damage.

On February 2, 1976, General Electric engineers in the Nuclear Energy Division, Gregory C. Minor, Richard B. Hubbard, and Dale G. Bridenbaugh, the “GE Three,” resigned from the

company and held a press conference.261 They were dismayed by their design of the Mark I containment and wished to come clean. The structure was just too fragile to stay together and prevent what it was supposed to prevent in an unlikely but not impossible reactor breakdown, they announced. It was not a good day in San Jose, home of GE Nuclear. A Mark I Owners Group was formed by concerned power companies.

In 1980, not a moment too soon, GE issued three important modifications for the Mark I containment structures currently in use. The “ram’s head” terminals on the steam pipes into the torus, which could exert a rocket-like thrust when steam rushed through them, were to be unbolted, thrown away, and replaced with spargers that would distribute and release steam in small doses under the water. Deflectors were to be welded into the insides of each torus, to prevent water waves from developing in the wet well under steaming conditions, and the support irons underneath the torus were to be bolstered. All plant owners executed these modifications, including TEPCO for the five reactors having Mark I containments at Fukushima I 262

This was hardly the end of the matter, and over the next few years there were several studies, simulations, and scale-model tests of the mercilessly persecuted Mark I by Lawrence Livermore Laboratories, the University of California Berkeley, and the Nuclear Regulatory Commission. Of particular interest was how the dry well would perform with 787,200 gallons of

water sloshing back and forth in it under earthquake conditions.263 By this time, GE had introduced its radically improved design, the Mark III containment, and the Mark I was supported as a thoroughly vetted, field-modified, and improved legacy system.

All General Electric BWRs were equipped with several reactor safety systems, designed to prevent fuel meltdowns, radiation release to the environment, and general damage to the system in the event of the worst accident that could possibly happen. This hypothetical event, named the “design basis accident,” was planned assuming that the operating staff had lost control of the power plant and that there were multiple equipment failures. Safety systems were designed to begin operating automatically, with no help from the staff. Any such system could be deactivated by an operator, but if there were no operators present and making decisions, the safety systems would sense the condition of the power plant using electronic instrumentation and digital logic, and thus were capable of operating as designed without human intervention.

Unit 1 at Fukushima, the oldest BWR, was equipped with an isolation condenser. In any emergency shutdown (scram), the turbine shuts down and the steam line to the reactor is shut off immediately. This action prevents any radioactive debris from possible fuel leakage from contaminating the turbine, but it also isolates the reactor vessel from its normal cooling loop. Even in full shutdown, a reactor generates significant heat for several days, so something must take the place of the cool water that returns from the steam condenser underneath the

turbine.264 The isolation condenser was designed for this purpose, operating as an emergency alternative to the primary cooling loop without needing any external power.

The condenser is located in the reactor building, on the refueling floor, above the reactor vessel and the dry well. A pipe runs from the top of the reactor to a small condenser in a tank of water. The cool-water return pipe from the condenser connects to the bottom of the reactor. As the water in the tank absorbs heat from the reactor, it boils off and leaves the building through a pipe in the wall, blowing off into the air. There is enough water kept in the tank to cool the reactor for three days, and there is an external connection for a fire truck to refill it. Water circulates through the condenser loop by gravity. The hot water rises from the reactor top into the condenser, and the heavier cooled water is pushed by gravity into the bottom of the reactor. A remote-controlled valve in the cold leg is used to turn the system on and off. The

isolation condenser is simple and seemingly foolproof.265

In addition, all of the reactors at Fukushima that were in service were equipped with high — pressure coolant injection systems (HPCI) for emergency use. The HPCI (pronounced “hip — see,” with the accent on the first syllable) is designed to inject great quantities of water into the reactor while it is maintaining normal operating pressure in shutdown mode, assuming that there is not a major steam pipe broken. This system does not rely on external electrical power to run the high-pressure water pump. It is turned by its own, dedicated steam turbine, which is connected to the steam pipe on top of the reactor, exhausting into the wet well. It spins up 10 seconds after a scram, and delivers cooling water taken from the pool in the torus at the rate of

3,003 gallons per minute.266 For it to work, nine valves must be open.

Units 2, 3, 4, and 5 were BWR/4s, and were nearly twice as powerful as Unit 1. An early BWR/4 was rated at 2,381 megawatts thermal, whereas Unit 1 was rated at 1,380 megawatts thermal. These reactors dispensed with the isolation condenser for emergency use, and instead used the more aggressive reactor isolation cooling system (RCIC, pronounced “rick-see”). Its operation is similar to the HPCI, using a steam-driven pump to circulate water through the reactor vessel when the normal cooling loop is shut off, and it can even compensate for coolant leaking from broken pipes. Another nine remote-control valves must be open for it to operate, and its use must be monitored and controlled, else it will overfill the reactor and send water down its own steam pipe. It takes water from a dedicated water tank, which is also used to maintain the water supply in the torus “wet well.”

If the pressure in the reactor vessel reaches the danger level, 1,056.1 pounds per square inch, a steam-relief valve opens and blows down through a pipe into the torus, where the steam

and gas are released underwater and are calmed down.267 The combination of dry and wet well containment is large enough to reduce the high pressure originating in the reactor vessel, but if the pressure in the torus should go beyond the design pressure of 62.4 pounds per square inch, a valve must open or the torus will explode. Under this condition of extreme emergency, the steam and gas are sent up the ventilation stack and into the environment, possibly containing radioactive fission products. This is a last-ditch measure, meant to keep from causing a major break in the containment structure which would allow uncontrollable leakage of the entire reactor contents outside the reactor building. To make it up the stack, the pressurized gas and steam must break a rupture disc in the pipe, calibrated to fail only at desperately high pressure.

The engineers at GE tried to think of everything that could possibly happen, and a system or a workaround was designed for problems that seemed highly unlikely. Units 2 through 6 at Fukushima were even equipped with residual-heat removal systems using four electrically driven pumps to cool down the reactors using seawater. There was one common weakness, however, for all the safety systems: they all depended on electricity.

Each valve in the complex maze of piping required electricity to open or close it.268 If the plant scrams in an emergency, then it stops providing electrical power to itself. In this condition, it switches to external power off the grid or to a cross-wired connection to the reactor next door. If no power is available on the power-plant site or from the area outside the plant, then each reactor has two emergency diesel-powered generators that come on automatically. Either generator is capable of handling the electrical needs of the entire plant, in case one breaks down or will not start. If the backup generators will not start, then the last resort is a room filled with lead-acid storage batteries, kept charged up at all times. They will supply direct-current power to the control room for eight hours, which is plenty of time to open the necessary valves and start the emergency cooling systems, which will then run on their own without any

electricity.269 The control-room lighting, the system-monitoring instruments, and the valve actuators are built to run on the DC current from the batteries under this extreme emergency. Condensate or coolant pumps will not run on the batteries.

It took over 12 years to complete the Fukushima I power plant, with the last, Unit 6, starting commercial operation in October of 1979. Although each reactor was a General Electric BWR, no two reactors were just alike. There were constant improvements implemented by GE in the 1970s, and the technical sophistication of the reactor systems increased as units were added to the plant. The TEPCO engineers made certain that the plant met the special requirements for reactors built in a heavy earthquake zone. The earth was bulldozed off the site so that the reactors could be built on solid bedrock, reducing the horizontal earth movement during an earthquake to a minimum, and a tsunami wall was built down on the beach, protecting the plant

from an ocean wave as high as 18.7 feet.270 Two breakwaters, one north and one south, spread out from the beach and onto the sea floor to prevent waves from silting up the water intakes.

Each reactor was equipped with two large water-cooled diesel backup generators, located in the lowest part of the plant, completely underground, in the basement of the turbine building facing the ocean. Electric pumps brought in seawater to cool the engines and dumped it back into the ocean. The battery rooms and the electrical switchgear spaces were also in the basement, on the inboard side of the turbine building. The control room was two stories up, connected to the turbine building. As much equipment as possible was shared between pairs of reactors, especially the vent stacks. Units 3 and 4, for example, shared one 600-foot stack, exceptionally well braced for earthquakes.

There were exceptions. Units 2 and 4 had one water-cooled diesel and one air-cooled diesel. The Unit 4 air-cooled engine was down for maintenance and was in pieces on the floor. Unit 6, the more advanced BWR/5, had two water-cooled diesels in the basement, but there was a third generator located above ground in an auxiliary building. It was air-cooled.

In March 2011, Units 4, 5, and 6 were down for refueling and maintenance. Unit 4 was in the middle of refueling, with the dry-well lid and the reactor vessel cover unbolted and placed aside using the overhead crane in the reactor building. The refueling floor was flooded, and all the fuel had been moved to the adjacent fuel pool for a cool-down period. The only things turned on in the Unit 4 building were the overhead lights and the coolant pumps for the open fuel pool, keeping water moving over the spent fuel as its residual heat tapered off exponentially. Units 5 and 6 had just finished refueling, and Unit 5 was undergoing a reactor-vessel leakage test. Units 1, 2, and 3 were running hot, straight, and normal, and three 275-kilovolt line-sets were humming softly.

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were in the middle of refueling when the Tohoku earthquake struck Japan. Both reactors were completely inert, with no fear of a meltdown or a hydrogen explosion. The fuel had been emptied from the reactor vessel and transferred to the storage pool using the refueling machine.

On March 9, 2011, 70 miles offshore, the Pacific Plate tried to slip under the Okhotsk Plate, 20 miles under the ocean floor. A magnitude 7.2 earthquake hit Japan. It caused the reactors on the northeast coast to scram due to indications from the ground-motion sensors, including Units 1, 2, and 3 at Fukushima, and it made the news, but nobody was hurt. Three more earthquakes the same day shook the ground. It was just another day in Japan, and life resumed a normal path after the bothersome disturbances. The reactors immediately restarted and resumed power production.

Earthquake prediction is a science in Japan, explored with more enthusiasm than anywhere else on Earth. Accelerometers are spread over Japan and out into the sea floor, and tsunami warning buoys are anchored offshore. These sensors can detect ground or ocean floor movement and send signals back to the Japan Meteorological Agency (JMA) at the speed of light over electrical cables. The earthquake shock travels much slower, at the speed of sound through rock (about 3.7 miles per second), and, depending on how far out the disturbance is, there can be minutes of warning issued by JMA. That is enough time to crawl under something solid or race out the front door of a building. The entire country is wired with earthquake alarms, designed to go off upon ground-movement detection from the array of accelerometers.

On Friday, March 11, at 2:46:43 Japan Standard Time, two days after the four minor earthquake shocks, Mikoto Nagai, head of the Emergency Response Team in Sendai, was at his desk on the third floor of an earthquake-proof building, sipping coffee. A lot of engineering thought had gone into how to make a building withstand ground accelerations. As Japan rebuilt after having been bombed to the topsoil during World War II, most of the new structures were constructed to sway without the foundation crumbling and the vertical support beams splintering. The early-warning earthquake alarm went off. Nagai put down his cup and looked up at the LED display bolted to the wall. It flashed 100 followed by a 4. In 100 seconds, a hit from a magnitude 4.0 earthquake was expected. The display quickly changed its mind. Make that a 6.0. No, an 8.0. Nagai stood up, and his coffee cup bounced sideways off the desk. Bookshelves collapsed, the internal wall in front of him came down, and people started screaming.

The Pacific plate had successfully relieved the east-west tension and hit Japan with its biggest

earthquake ever recorded. It was 9.0 on the dimensionless Moment Magnitude scale.271 In three minutes, the eastern coastline of Japan fell 2.6 feet, and Japan moved 8 feet closer to

California.272 The rotational axis of the Earth tilted by 10 inches. Roads were churned, high — voltage power lines were downed, and 383,429 buildings were destroyed.

The point in Japan nearest the epicenter of the earthquake was Onagawa in the Oshika District, and on a point of land jutting out into the Pacific Ocean was constructed the Onagawa Nuclear Power Plant by the Tohoku Electric Power Company, down on the beach. It consists of one BWR/4 and two BWR/5s, built by Toshiba under contract with General Electric. The last one started operation on January 30, 2002. As it was the newest reactor of the group, it has the most updated earthquake hardening techniques applied to it, and it has a substantial, 46- foot tsunami wall between it and the surf. The earthquake rolled through Onagawa, scrammed all three reactors, and subsided without doing any damage to the power plant. All the workers’ homes within driving distance of the site, however, were leveled to the ground.

About 22 seconds after it hit Onagawa, the ground-shock hit Fukushima I, which was twice the distance from the epicenter. An inspector for the Nuclear Industrial and Safety Agency, Kazuma Yokata, was permanently stationed in the office building at Fukushima I, in the no­man’s land between Unit 1 and Unit 5. He heard the alarm go off, but he was not overly concerned until the ceiling appeared to be coming down on him. He cringed as the L-shaped brackets holding up the bookshelves ripped out of the wall and his thick binders containing rules and regulations started flying.

There were 6,413 workers on the Fukushima I site that day. One of them, Kazuhiko Matsumoto, was in the turbine building for Unit 6, finishing some work on air ducts. He suddenly found that it was impossible to remain standing on the sparkling clean deck, and he had to cling to a wall to keep from being dribbled on the floor like a basketball. The lights went out, and the windowless expanse of the turbine hall went black. In a few seconds the emergency lights turned on, and over the loudspeaker came a simple instruction: “Get out.”

Fukushima I was built to withstand a horizontal ground acceleration due to an earthquake of 0.447g (1g = 32 feet per second per second). Unfortunately, this 9.0 earthquake came in at

0.561g.273 The reactors, particularly the three earliest units that were running at full power,

were treated roughly. Some pipe runs ripped out of wall anchors, all external power lines went down, and anything not bolted down went flying. Fortunately, almost everything in a nuclear plant is bolted down. All 12 available emergency generators came on after a few seconds with the control rooms running on batteries. Over the next minutes, several aftershocks hit the island, with magnitudes up to 7.2.

With full AC power from the emergency generators, the three reactors that had been running at full power experienced orderly shutdowns, with the cores being cooled by the usual means, and everything was under control. At Unit 1, the completely passive isolation condensers were doing their job, cooling down the reactor core after shutting down from running at full power. There was no need to turn on the HPCI, at least not yet.

In the opinion of the reactor operators, the isolation condenser was doing its job too well. The temperature was falling too rapidly, and, with the steam condensing in the reactor vessel, a pipe could be collapsed from the vacuum it created. Over-thinking the simple, hard-wired digital logic that had turned it on, an operator put his hand on the switch handle that would stop the isolation condenser coolant flow and turned it off. Then, the remotely controlled flow valves

MO-3-A and MO-3-B closed.274

In major commercial reactor accidents, there always seems to be a single operator action that starts the downward spiral into an irrecoverable disaster. In the case of Fukushima I, closing those two valves at Unit 1 was the turning point. With that simple action, overriding the judgment of the automatic safety system, an operator doomed Fukushima I to be the only power plant in Japan that suffered irreparable damage due to the Tohoku earthquake of

2011.275

At 3:27 P. M., 41 minutes after the earthquake, a tsunami hit the beach at Fukushima I with a towering wave, 13 feet high. The wall built in front of the plant kept the wave from harming anything. Eight minutes later, a second and then a third wave hit. At 49 feet high, they went

over the 18.7-foot wall and inundated the entire plant.276

The water-intake structures for all six reactors were collapsed by the wave, the water pumps were blown down, and any electrical service outside the buildings was shorted out by the salt water and then torn away. In six minutes, all the underground diesel generators were flooded, and the emergency AC power failed. One diesel-powered generator, the air-cooled unit located above ground at Unit 6, remained online, providing power for Units 5 and 6. Units 3 and 4 were now on DC power, enabling operators to read instruments in the control room and manipulate remote-control valves until the batteries lost power, and now was a good time to make sure all the valves were in an open/close condition that would do the most good, keeping the core of Unit 3, recently operating at full power, from melting. In Units 1 and 2, the battery room was flooded, and the plant was in total blackout. No valves could be turned on or off, and the status of reactor systems was not available on the control panels. They were stuck with whatever configuration was in effect when the lights went off, and that meant that Unit 1 was coming down off full power with nothing to cool its 69 tons of hot uranium oxide fuel, continuing to generate megawatts of power. The isolation condenser was shut off. In Unit 2, at least the RCIC was left running when the power failed, but without some tweaking, it too would fail eventually. TEPCO advised the Japanese government that an emergency condition existed at

Fukushima I.

The tsunami rushed inland, to the ancient tsunami warning stones and beyond, carrying everything with it and drowning the Earth beneath it. Fishing boats and ocean-going ships hit the beaches and kept going. Down came houses, factories, and entire towns. Cars, trucks, and trains were moved like toys in a fire-hose spray. Power transformers blew up as electrical lines touched the ground, gas lines broke, and fires broke out, taking out any last burnable structures that had not washed away.

The wave came in, and then it went out, taking everything that would float out to sea. An estimated 18,000 human beings were washed into the Pacific Ocean. The loss of life was devastating. Two operators drowned at Fukushima Unit 4, trapped in the turbine building as the water quickly rose in the basement.

The immediate crisis at Fukushima I was a need for AC power to manage the cooldowns in Units 1, 2, and 3. Unit 1 was in total blackout with no passive systems running, and in 2 and 3 the water circulated through the torus pool was eventually going to have absorbed enough heat to start steaming. All the reactor interconnection cables, allowing the units to share 6.9 kilovolt and 480 volt power, had been lost in the tsunami. An obvious solution was to bring in portable diesel generators and hook up to whatever wiring stubs were left sticking out of the buildings, but this was not going to be simple. All roads into Fukushima I were either completely washed away, blocked by collapsed buildings, or jammed by fleeing people. Appropriate generators were available, but they were too heavy to be flown in by helicopter. They could only be transported by wide trucks on a smooth highway.

The plant wiring was also a problem. Temporary cables would have to be installed, first

running from the plant parking lot to the standby liquid-control pumps for Unit 2.277 Cables were available, but they were four inches in diameter, 656 feet long, and weighed more than a ton. Unreeling the cables and running through debris field covered with collapsed buildings and newly established lakes would have to be done without any powered equipment. No trucks, cranes, or bulldozers were available, and hidden beneath the ground clutter were manholes with the covers blown off. Everything about establishing AC power involved tremendous adversity, and it was going to take time.

In Unit 1 there was no instrument feedback revealing the state of the systems and no lighting in the control room. The operators could only look at the dead instruments using flashlights. By three hours after the earthquake, all the steam-relief valves had pried open and the water had boiled out of the reactor core. An hour and a half later, the fuel, still generating power at a fractional rate but naked of liquid coolant, started to melt away the zirconium sleeves on the fuel pins. The red-hot zirconium began to react chemically with the steam around it, oxidizing and leaving hydrogen gas in place of the steam. The zirconium core supports started to get soft and sag, and entire fuel assemblies started coming apart and tumbling down into the bottom of the reactor vessel. There were 400 fuel assemblies, and each one was 171 inches long. Compressed by the weight of the fuel, the wrecked mixture of uranium oxide, zirconium oxide, and melted neutron control blades increased its temperature. Fuel started to melt.

The combination of steam pressure and hydrogen gas pressure vented from the isolated reactor vessel exceeded the designed yield strength of the torus several times over. There was no electricity to open any valves, so the normal severe emergency action of venting the torus safely up the vent stack could not be initiated. General Electric’s Mark I containment, made of steel one inch thick, split open, and the soluble and volatile components of fission products, set free by the absence of any zirconium cladding, were sprayed into the reactor building. Included with it was hydrogen gas, mixing with the oxygen-containing air in the large space above the refueling floor. Unit 1 was now a bomb, set to go off and heavily contaminated with fission products.

The operating staff at Unit 1 knew that after being without a cooling system for several hours, the Mark I would have to be vented up the stack, but there was no power to open the main valve, AO-72. It was an air-operated valve, but it was possible to open it by hand if they could get to it. The entire reactor building was radiation-contaminated, which was a clue that the containment structure was already broken open, but men volunteered for the hazardous job of running down pitch-dark hallways, through a maze of doorways and passages, to the valve, open it by turning on a compressed-air line, and rush back, receiving the maximum allowable dose for the entire month in a few minutes. First, a gasoline-engine air compressor would have to be located and connected to the line. Every detail took time.

The entire area around Fukushima would have to be evacuated before it was legal to vent the containment, and government permission had to be verified. The TEPCO office in Tokyo finally gave the go-ahead at 9:03 a. m. on March 12, the next day. At 2:30 P. M., after heroic effort, the torus in Unit 1 was vented up the stack shared with Unit 2, but it was too late to prevent damage to the plant.

At 3:30 P. M., the men at Fukushima I had bucked all odds and installed external AC power to the standby pumps at Unit 2. With great effort, fire hoses had been attached to the outside access points for the condensate tanks in Units 1 and 2, and fire trucks were standing by to start pumping water and relieve the obvious heat buildup inside.

The men paused a moment to rest and admire their work. Six minutes later, at 3:36 P. M., the Unit 1 reactor building exploded in a spectacular geyser of debris, sending radiation — contaminated chunks of concrete and steel beams high in the air and careering through the newly installed equipment. Five men were injured, the wiring was ripped out, the generator was damaged, and the fire hoses were torn. Heavy debris came down all around for what seemed a long time. Radioactive dust from the Unit 1 fuel floated down out of the air and began to cover

the entire power plant.278 Not only had this explosion destroyed Unit 1, but from now on all work at Fukushima I would require heavy, bulky radiation suits and respirators, and now there was a new layer of movement-restricting debris on top of the already-established debris. It was a setback.

The next day, at 2:42 am. on March 13, the passive high-pressure coolant injection (HPCI) system in Unit 3, running on steam made from the afterglow in the fuel, finally gave out, and by 4:00 am. the fuel began to degrade, eventually collapsing into the bottom of the reactor vessel and generating a great deal of hydrogen gas. A fire engine was eventually able to inject seawater into the system, effectively closing the gate after the livestock had escaped. By 8:41 am., the operators had managed to open the air-operated torus vent valve and relieve the pressure that was building up. It was seen as a semi-miracle. Steam was seen coming out the vent stack, and the site boundary dose rate suddenly increased to 0.882 rem per hour.

At 11:01 am. on March 14, the day after the Unit 3 core structure melted, the Unit 3 reactor building exploded with a fireball, taking the lead over Unit 1 for the ugliest debris field. Hydrogen gas from the core deterioration had collected in the top of the building until it reached a critical concentration, somewhere over 4% in the air, and a spark must have set it off. Two fire engines were put out of commission, 11 workers were injured, the portable generators that were now collecting in the yard were all damaged, the temporary wiring was torn out, and the fire hoses were ripped apart. The new debris on the ground, everything from dust to chunks of walls, was extremely radioactive. The dose rate in the Unit 3 airlock, not even entering the reactor building, was now 30 rem per hour. The absolute emergency dose allowed one worker at the plant was 10 rem. That meant that if a worker stood in the airlock for 20 minutes, he had to be relieved and sent away, and he could no longer work on the problems at the plant. Debris on the ground after the Unit 3 explosion caused a dose rate of 1 rem per hour in the yard, and all personnel outside the control room were evacuated to the Emergency Response Center, near Unit 5.

At 12:40 P. M. the Reactor Core Isolation Cooling System (RCIC) in Unit 2 had absorbed all the shutdown heat it could stand, and the coolant-pump turbine stopped turning. It had held out for 70 hours, outperforming its design. The water in the reactor vessel boiled away, overstressing the Mark I containment structure, and at 4:30 P. M. the fuel pins started to melt, eventually falling into the bottom of the vessel and vigorously making hydrogen. Fortunately for Unit 2, the explosion of Unit 1 had blown a large hole in the side of the reactor building, so all the hydrogen leaking out of the torus was able to escape freely and not collect near the ceiling. Unit 2 never exploded, but its radioactive steam, iodine, and xenon were able to escape into the environment along with the hydrogen. Plans to vent the torus were cancelled when the pressure inside was found to be too low to open the rupture disc on the vent stack.

As the situation at Units 1, 2, and 3 continued to deteriorate, Unit 4 remained serenely innocent. All its fuel had been removed and stored in the fuel pool on the top floor in the reactor building. The cooling water surrounding the fuel was at 80.6° Fahrenheit, the tops were off the reactor vessel and the dry well portion of the containment structure, and nothing was anywhere near a crisis condition. The electrical power was gone, but Units 1, 2, and 3 were in continuous crisis, and they obviously needed more attention than Unit 4. The operating staff pitched in to help the units that were in deep trouble.

The fact that there was no power meant that the Unit 4 vent-stack damper valves had no compressed air holding them closed. They were, in fact, hanging open. Unit 4, for reasons of economy, shared a vent stack with Unit 3. There was no backflow damper installed, so when the overpressurized torus in Unit 3, heavily invested with hydrogen, was vented up the stack, using the correct procedures by the book, half of the vented gas went up the stack and half went back through the Unit 4 vent pipe. The hydrogen and radioactive steam proceeded through the relaxed valves in the Standby Gas Treatment System filters, up two stories, and out the exhaust air ducts on the fourth floor of the Unit 4 reactor building, where it collected at the ceiling and awaited an ignition spark.

At 6:14 a. m. on March 15, four days after the earthquake, the Unit 4 reactor building exploded with a mighty roar, much to the surprise of everyone working at Fukushima I. Having no theory as to what had just happened, the operators at Units 5 and 6 quickly climbed to the tops of the reactor buildings and hacked large holes in both roofs to let out the hydrogen, which did not exist, thus inflicting the only damage that the two newer reactors sustained in the Tohoku earthquake.

The cross-contamination of hydrogen and radioactive steam from Unit 3 was not figured out until August 25, and on March 15 the only plausible explanation was that the water in the fuel pool must have leaked out through a crack caused by the earthquake. The spent fuel, removed from the reactor core only days before, must have overheated and caused its zirconium cladding to generate hydrogen from the remaining steam in the pool. A helicopter flyover confirmed a great deal of radioactivity in the remains of the upper reactor building. A great deal of effort and time was spent in vain, trying to reload the fuel pool with water using helicopter drops and water cannons. It turned out that the fuel in Unit 4 was in fine condition, and the high radioactivity over the building resulted from dissolved fission products delivered to the space above the refueling floor by steam from Unit 3.

After the upper floor on the Unit 4 reactor exploded, there was basically nothing left to happen that could further degrade Fukushima I. The three reactors that were operating when the earthquake hit had melted down and were left an enormous liability for TEPCO. It would be feasible to rebuild Unit 4, because only the roof and walls covering the refueling floor had been blown up, but the radioactivity spread all over the power-plant grounds would make it an impractical work environment. Units 5 and 6, the newest reactors in the plant, could be brought back online with some rebuilding of the seawater intakes, new outside pumps, and an enhanced tsunami wall.

Unfortunately, the wind had shifted to an east-to-west direction during the disaster. Starting at the Fukushima beach, a swath of farmland running northeast about six miles wide by 25 miles long, washed of human habitation by the tsunami, may be too contaminated by fission product fallout to be repopulated immediately. It may be turned into a nature preserve. Every time it rains at Fukushima I, more radioactive dust is washed down to the shore and out into the ocean, causing issues for Japan’s sizable fishing industry.

None of the spent fuel at Fukushima I, in cooling pools or dry storage, was damaged and no fission products from it leaked into the environment. All of the radioactive contamination was from damaged, hot fuel exposed to steam, which was allowed to escape from Mark I containment structures, stressed beyond the imaginations of the engineers who had designed them. No one had considered that a reactor coming down off full power could be denied electricity for more than a few minutes, given the multi-level, parallel-redundant systems built to prevent it. After Unit 1 blew up, refilling the condensate tanks from external sources and wiring up emergency generators was delayed, and the remaining reactors fell like dominoes. Without an ultimate heat sink, the core structure in a nuclear reactor that has recently generated a billion watts of power will eventually melt from the delayed energy release in the fuel. If the workers had been able to refill the condensate tanks in Units 2 and 3, there would have been a lot of steam, but the vapor would not have contained any dissolved fuel, and it would not have been radioactive. With externally provided water and electricity, Units 2 and 3 would have

survived.279

Nothing melted through the bottom of a steel reactor vessel at Fukushima. After accidents at Three Mile Island and Fukushima, fears of a “China syndrome” melt-through begin to seem unfounded. There is simply not enough heat generated by tons of hot fuel to make a hole in the

bottom of a water-moderated reactor.

The workers at Fukushima I were dedicated to the tasks of bringing the reactors at the plant under control, with cold shutdowns a goal, and they worked without sleep, food, a way to get home, news from loved ones, or a remaining dwelling place, in a potentially dangerous radiation field. Two operators in the Unit 3 and 4 shared control room wore glasses, and their respirators would not fit correctly over their spectacles. Air containing radioactive dust leaked in to their breathing apparatus. One received a dose of 59 rem, and one received 64 rem. These were serious but not immediately fatal lung exposures. With workers retreating inside as the result of various explosions, the Emergency Response Center became heavily contaminated with radioactive dirt, and there were no controls in place to prevent radiation exposures. Workers who never worked near a reactor received substantial internal radiation doses. One woman, for example, received a dose of 1.35 rem.

As of September 1, 2013, there have been 10,095 aftershocks from the Tohoku earthquake of March 11, 2011.

With four nuclear power plants in a direct line of the tsunami waves following the Tohoku earthquake, what was it specifically about Fukushima I that caused it to be destroyed that made it different from other reactors? TEPCO, having ignored studies warning of a major earthquake and a tall tsunami, was widely blamed for the disaster. None of the preparations for a major off-shore earthquake were adequate, and the probability of an earthquake disaster, and the likelihood of a corollary tsunami, was not taken seriously. The nuclear regulatory structure in Japan as well as the prime minister himself were under fire for not having insisted on more rigorous safety inspections and preparations, but what caused this highly localized breakdown when seventeen other nuclear power plants around Japan were rattled in the same earthquake? Those plants located on the east coast were even hit with the same tsunami.

Consider the fate of Fukushima II, a nuclear power plant built by TEPCO, seven miles down the coast from Fukushima I. It is a newer power plant, having four General Electric BWR/5 reactors with Mark II containment structures, built under license by Toshiba and Hitachi. The reactors came online between 1981 and 1986, producing a combined 4.4 billion watts of electrical power. All four units were operating at full power on March 11, 2011, when the Tohoku earthquake struck Japan.

Immediately during the earthquake, all four units scrammed and automatically began emergency cool-down measures. Three out of four off-site power sources went down, and the emergency diesels started. A tsunami warning was issued, indicating that a wave at least 10 feet high was on its way. All operators were called to the control rooms, and everybody else was evacuated to high ground. In 36 minutes, the waves started coming. The highest in the area of the main buildings was 49 feet, and it swamped the 17.1-foot tsunami wall, covering the entire plant in seawater.

The tsunami knocked out the majority of emergency diesel generators and above-ground seawater pumps, but Unit 3 kept both its generators and its pumps, and Unit 4 still had one generator. The last remaining high-voltage electrical line out of the plant site after the earthquake remained operable. Using this off-site power and cross-connections with the three remaining diesels, all control-room instruments and controls remained in operation. All four reactors were depressurized, and coolant injection was established using the condensate water tanks, exactly as detailed in the written emergency procedures. Unit 1 required manual actuation of some motor-driven valves, but there was no radiation leakage or loss of lighting in the reactor building, and the workers were not dosed.

Unit 3 used its still-operational seawater pumps to achieve a cold shutdown, but Units 1, 2, and 4 used a spray of water from the condensation tanks to cool off the hot water pooled in the Mark II containment wet wells. New seawater pumps and a lot of temporary electrical cable were urgently needed, and TEPCO managed to find these supplies and lower them onto the plant site using helicopters the next day. About 200 workers, unimpeded by radiation contamination on the ground, installed the new motors and 5.6 miles of new electrical cable in 36 hours. By 3:42 P. M. on March 14, three days after the earthquake, all four units were being cooled using the seawater-driven Residual Heat Removal Systems, and the reactors were in cold shutdown on March 15.

The important differences between Fukushima I and Fukushima II seem to center on the ages of the two plants and the resulting differences in design sophistication. Nuclear-plant designs, all of which are experimental, rapidly evolved in the 1970s as lessons were learned and things that worked well were kept while things that did not work well were redesigned. The Mark II containment structure was a welcomed improvement and simplification of the much-debated Mark I.

Using air-cooled instead of seawater-cooled emergency diesel generators, located out of the basements and above ground, was also important. Being washed over by a wave was different from being soaked in a permanent pool of salt water, particularly if the engines used electrically driven pumps to circulate water out of the ocean, where the intakes were destroyed by the tsunami, and the electrical distribution boxes were left under water.

Fukushima II was also simply luckier than Fukushima I, which had its entire electrical switching yard wiped out, including the inter-unit electrical connections. Unit 1 at Fukushima I, having the smallest of the six reactors, had a lesser heat load to manage using the same Mark I containment structure that Units 1 and 3 had. Its set of two isolation condensers, unique to it at the plant, was ingenious and robust, and there was no reason why it could not have saved the reactor from destruction and brought it down to a cold shutdown without the convenience of emergency electrical power, if only it had not been turned off. The fate of Fukushima I, the safety reputation of American-designed light-water reactors, the remains of the nuclear power industry, and the background radiation in the Sendai Province could all have been different.

Take a step back and contemplate the sampling of nuclear wreckage that has been laid out before you in the ten chapters of this too-brief narrative. You can see patterns developed in this matrix of events. There are hot spots, imprints, and repetitions. The markings are all over the developed world, left there by one very large experimental program that was trying to improve the lot of mankind, and not to destroy or degrade it. The boldness of this long-term program can raise an eyebrow or two, but from an engineering standpoint it was new, exciting, unexplored territory. In all, it killed fewer people than the coal industry, it caused less unhealthy

pollution than the asbestos industry, and it cannot be blamed for global warming.280 In the last chapter, we will discuss what it all means and reach for what conclusions there are.

257 In the early 20th century Japan wanted to step up to electrical power, just like everyone else in the developed world, but there were at least two

modes of alternating current in use. Europe had chosen an alternating frequency of 50 hertz, and America had chosen 60 hertz. Japan, still recovering

from centuries of non-centralized government using the warlord model, found that the south end had chosen to buy generating equipment from Westinghouse, and it all ran on 60 hertz. The north end, on the other hand, had bought equipment from Siemens A. G., and it ran at 50 hertz. The two transmission modes are incompatible, and the north-south divide of electrical current exists to this day In a broad emergency this discontinuity makes it difficult to ship electricity from an undamaged southern end to the devastated northern end of Japan. A small number of frequency-converter stations exist on the boundary, but their capacity is overwhelmed in a disaster.

258 There have been many recorded earthquakes originating off shore that caused tsunami destruction in Japan. The one referred to on the “tsunami stones” is probably the Jogan Sanriki earthquake, which occurred at the Pacific/Okhotsk subduction zone on July 9, 869 (the 25th day of the 5th month, 11th year of Jogan). Its magnitude is estimated at 8.6. The existing stones may be replacements for original warnings that eventually became unreadable due to advanced age.

259 The GE BWR/1, designed in 1955 and installed at the Dresden Generating Station in Illinois, used an external steam separator/dryer. The Soviet RBMK reactors, such as Reactor no. 4 at Chernobyl, were boiling-water reactors using multiple external steam separators.

260 Technically the Wuergassen plant was not a GE, as it was built by AEG. AEG, however, did not design the reactor itself, but paid for a license from GE to build their latest model BWR. If there was something wrong with the Mark I, it was not the fault of AEG.

261 The three merry whistleblowers formed a consulting company MHB Technical Associates. They were hired as technical experts for, of all things, Jane Fonda’s movie The China Syndrome.

262 All the reactors at Fukushima I were BWR/4s with Mark I containments, except the 6th and last reactor installed. It was a BWR/5 with a Mark II containment. The Mark II was a complete redesign, having a lot of concrete backing up the steel structure. Reactor No. 6 came online on October 24, 1979. Reactors 3 and 5 were built by Toshiba under license from GE, and Reactor 4 was built by Hitachi with a similar agreement.

263 The report from the initial study “Sloshing of Water in Torus Suppression-Pool of Boiling Water Reactors Under Earthquake Ground Motions” (LBL — 7984), was released in August 1978. It arrived at no negative conclusions regarding the behavior of the wet well in an earthquake, but demonstrated a good agreement between the mathematical finite elements model and a 1/60 scale model of the torus given a shake equivalent to the El Centro Earthquake of 1940.

264 In fact, the water returning from the condenser is too cool to be put back in the reactor vessel. A typical GE BWR uses five stages of pre-heater in the return leg of the primary cooling loop. Heat for these pre-heaters comes from “extraction steam,” or steam directly out of the first (high-pressure) stage of the three-stage steam turbine. The extraction steam is then fed back into the condenser and cooled with the rest of the steam from the turbine. Newer BWRs have a simplified system using electrically driven heaters.

265 The same scheme, called “thermo siphon,” was used to cool the engine of the Model T Ford automobile without the use of a motor-driven water pump. Reactor No. 1 had two isolation condensers, in case one failed. Each water tank held 28,002 gallons of water and was capable of handling 116 tons of steam per hour.

266 The number given, 3,003 gpm, is only for Reactor No. 1. No. 2 and No. 3 pump at the rate of 4,249 gpm.

267 That describes the first steam-relief valve. There are eight in a BWR/3 and 16 in a BWR/4, with progressively larger blow-off pressures. The last one opens at 1,130.1 psig.

268 The larger valves are opened and closed by air pressure supplied by an electrically driven air compressor. For air-operated valves to be manipulated in emergency conditions, compressed-air bottles are provided, but the air valve is still opened or closed remotely by an electric signal. It is possible to open up the RCIC system manually but it is not easy If there is already radiation leakage in the reactor building, then the time limit for people working in the area to open a valve is strictly limited by the permissible dose and the dose-rate in the building.

269 It says eight hours in the battery advertisements and in the plant specifications, but performance may vary. Running a reactor on storage batteries can be as disappointing as a laptop computer in an airport waiting area when your flight has been delayed. It will power-down due to low battery just as your iPod dies.

270 The United States is not above building a nuclear power plant on the beach in the Ring of Fire. The Diablo Canyon Nuclear Power Plant in California is built facing the Pacific Ocean, using it as the source of coolant. Fukushima has an 18.7-foot tsunami wall, but Diablo Canyon has a 32-foot tsunami wall. There is no evidence of a wave this high ever having washed over the Diablo Canyon property.

271 One is tempted to write “Richter scale.” Somehow, it sounds better, but Richter is now considered to be an obsolete relic from 1935. It has been replaced by the Moment Magnitude scale, which expresses the energy released from an earthquake on a base-10 logarithm scale. There are correction factors added to the formula, but it is basically the same value as the old Richter scale, +/-0.6. A 9.0 event is 100 times more powerful than a 7.0 event.

272 The sinking of Japan had an effect on the rotational speed of the Earth. Just as a spinning ice skater speeds up by pulling in her arms, the Earth’s rotation sped up slightly decreasing the length of a day by 1.8 microseconds as the mass of Honshu Island drew downward, toward the center of the Earth.

273 The Diablo Canyon Nuclear Power Plant, the American equivalent of Fukushima I built on the coast in California, is built to withstand a horizontal ground acceleration of 0.750g.

274 The closing of these valves is surprisingly complex. The operators were “cycling” Isolation Condenser A, turning it on and off, trying to slow the temperature descent, with Condenser B turned off. Both condensers, A and B, had been turned on automatically by the scram-control logic. The last operator action was to cycle Condenser A down by turning off the cold-leg return valve, which was motor-operated.

275 There is a strange twist here. The operators at Unit 1 were desperate to restart the isolation condensers or to initiate the HPCI, but there was no DC current from the backup batteries. They stormed what was left of the plant parking lot, where the 6,413 workers had left their cars, and started pulling batteries out of the cars that remained on site, and, where available, they took jumper cables out of trunks. They stacked batteries on the floor in the control room, connecting ten 12-volt batteries in series using the jumper cables to make 125 volts DC for the valve-control motors. There was not enough current to keep the system alive for more than a few minutes, but for an instant the control panel lighted up and they could see that the isolation condenser valves MO-2A and MO-3A indicated closed. At 6:18 P. M. they were able to apply power to the motors and open the valves. A lookout reported steam coming from the condenser pool, indicating success. Seven minutes later, an operator reached for the switch and closed the valves, just as the automobile battery-pack died. No reason for this action has been determined. The isolation condenser valves could not be reopened.

276 The precise height of the second and third waves is not known, and it is estimated by the level of silt on the buildings at between 46 and 49 feet. The wave meter at the plant was capable of recording a wave as high as 24.6 feet, where it jammed right before it was carried away by the wave. The tsunamis that hit Fukushima I were the sum of several circular waves originating sequentially at large sea-bed movements in the quake epicenter and in the Japan Trench, running north-south between Honshu and the epicenter. The wave transmitted across the Pacific Ocean as the circular wave components increased in radius, eventually hitting the California coast. No damage was done on the eastern side of the Pacific. A tsunami of the type that hit Japan starts out with a wavelength of about 120 miles, moving at 500 miles per hour. When it approaches shallow water, the wavelength

compresses to 12 miles, the wave-height expands, and the speed reduces to 50 miles per hour.

277 These pumps (SLC) were not flooded or damaged, and if they could be powered up, it would save Reactor 2 by cooling it down with seawater. Reactor 1 was in greater need of help, but starting the SLC pumps for Reactor 2 looked like something that could be accomplished. Unfortunately, the seaward intakes for the pumps were blocked.

278 Fortunately, at 3:36 P. M. on March 12, the wind at Fukushima I was blowing out to sea. It is never good to let radioactive dust settle over the ocean, but it would have been much worse to have it settle over the inland territory to the west of Fukushima. Much nuclear mischief can be lost at sea and rendered much less harmful, because the dilution factor is so enormous as opposed to when it stays on land.

279 The reactors would have survived, but the steam turbine rotors would have been ruined. A major job of the diesel backup generators is to keep the turbine turning, if even at a very slow speed, using the electrically driven “jacking gear.” A large steam turbine must be kept turning at all times. If allowed to sit still for a few hours, the rotors will sag, losing balance and rubbing against the metal shell that covers the turbine. In this distorted condition, the turbine cannot be restarted. The backup batteries will not maintain this essential service to the turbine.

280 Statistically for every person who dies as a result of the generation of electricity by nuclear means, 4,000 people die as a result of fine-particle pollution caused by burning coal. Between 1972 and 2002, 730,000 lawsuits were filed because of asbestos dust inhalation, costing the asbestos industry $70 billion. The deaths caused by asbestos are in the half-million-people range. Global warming is believed to be caused by a buildup of carbon dioxide in the atmosphere, caused by our digging or drilling up and burning carbon that was sequestered underground. This carbon was geologically kept out of the total carbon inventory on the surface, but the need for power in the industrialized world has made it necessary to release energy any way we can. Most of the extra carbon dioxide comes from burning coal, gasoline, and natural gas. Nuclear power generation does not oxidize anything, but derives energy from nuclear fission. Some have pointed out that building a nuclear plant requires a lot of fuel to pour concrete and workers drive to the plant in cars, but these are ridiculously weak arguments against non-polluting nuclear power.

Chapter 11

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