Fukushima – IEEE Engineering Retrospective

There is a rather remarkable article at the IEEE site. That’s the Institute of Electrical and Electronics Engineers. As nuclear power plants have a lot of electrical equipment in them, and it was a failure of electrical power that lead to the cascade failure, these folks have a strong interest in just what really happened. Their description is, IMHO, likely to be the most correct we’re likely to get for quite a while.


I strongly suggesting reading the whole thing and not just the snippets I’m going to put here as a ‘tease’. It reads better as written and it has some good and technically oriented pictures in it.

The “bottom line” is that there were several simple things that could be done differently that would prevent such an accident from happening again; yet since they were not done, the cascade failure has resulted in several cities being abandoned for the foreseeable future and nuclear power being ‘on the rocks’ in the industrialized west.

Some selected quotes:

24 Hours at Fukushima
A blow-by-blow account of the worst nuclear accident since Chernobyl

By Eliza Strickland / November 2011
On the other hand, close study of the disaster’s first 24 hours, before the cascade of failures carried reactor 1 beyond any hope of salvation, reveals clear inflection points where minor differences would have prevented events from spiraling out of control. Some of these are astonishingly simple: If the emergency generators had been installed on upper floors rather than in basements, for example, the disaster would have stopped before it began. And if workers had been able to vent gases in reactor 1 sooner, the rest of the plant’s destruction might well have been averted.

There is a picture of a room full of very large electrical equipment (that looks like giant motors and perhaps pumps) that are all under water. It is a gallery of pictures of equipment where clicking on the image let’s you page through the kind of photos that technical folks take, documenting the equipment and its condition. One shows a large control panel with a bunch of batteries in a row, connected by ‘jumper cables’, clearly scrounged from vehicles. Looks like 10 or 11 batteries, so at 12 VDC each, that would be 132 max and at 10 VDC (about where they are tapped out) 120 VDC. I wonder if the equipment was designed to run on DC, or if they were able to tap in just after a full wave bridge rectifier that made 120 VDC in normal use, followed by a DC Chopper and high frequency (so smaller sized inductors) DC power supply? Just wondering how ‘creative’ these guys had to become…

The world’s three major nuclear accidents had very different causes, but they have one important thing in common: In each case, the company or government agency in charge withheld critical information from the public. And in the absence of information, the panicked public began to associate all nuclear power with horror and radiation nightmares. The owner of the Fukushima plant, the Tokyo Electric Power Co. (TEPCO), has only made the situation worse by presenting the Japanese and global public with obfuscations instead of a clear-eyed accounting.
In the basements of turbine and reactor buildings, 6 of the 12 diesel generators shuddered to a halt as the floodwaters inundated them. Five other generators cut out when their power distribution panels were drenched. Only one generator, on the first floor of a building near unit 6, kept going; unlike the others, all of its equipment was above the water line. Reactor 6 and its sister unit, reactor 5, would weather the crisis without serious damage, thanks in part to that generator.
The isolation condenser, which relied on convection and gravity to perform its cooling function, should have helped keep the water level high in unit 1’s core through the crisis. But operators had turned off the system just before the tsunami by closing its valves—and there was no electric power to reopen them and let steam and water flow. Workers struggled to manually open the valves on the IC system, but experts believe the IC provided no help after the tsunami struck.
In the plant’s parking lots, workers raised car hoods, grabbed the batteries, and lugged them back to the control rooms. They found cables in storage rooms and studied diagrams. If they could connect the batteries to the instrument panels, they could at least determine the water levels in the pressure vessels.
TEPCO did have a backup for the emergency generators: power supply trucks outfitted with high-voltage dynamos. That afternoon, emergency managers at TEPCO’s Tokyo headquarters sent 11 power supply trucks racing toward Fukushima Dai-ichi, 250 km away. They promptly got stuck in traffic.
At around 9 p.m., operators finally plugged the car batteries they’d collected into the instrument panels and got a vital piece of information—the water level in reactor 1. The information seemed reassuring. The gauge registered a water level of 550 millimeters above the top of the fuel assembly, which, while far below normal safety standards, was enough to assure the operators that no fuel had melted yet.

But TEPCO’s later analysis found that the gauges were wrong. Months later, calculations would show that the superheated water inside the reactor 1 pressure vessel had dropped all the way below the bottom of the uranium fuel rods shortly before operators checked the gauge, leaving the reactor core completely uncovered.
It was after midnight when the first power supply trucks began to arrive at the site, creeping along cracked roads. The trucks parked outside the unit 2 turbine building, adjacent to the troubled unit 1, where workers had found one undamaged power control panel. In the darkness, they began snaking a 200-meter-long power cable through the mud-caked building in order to connect it to the power control panel. Usually trucks are used to lay such a cable, which weighed more than a ton, but that night 40 workers did the job by hand. It took them 5 hours.
That left one fire engine to cool the overheating reactor 1. This truck was the best hope for getting water into the pressure vessel quickly, but it took hours to maneuver it through the plant’s wreckage.
At 3:36 p.m., a spark flashed in the darkness of the reactor building, and hydrogen gas ignited. With a roar, the top of the reactor building exploded.

The roof shattered and the walls splintered; fragments of the building flew through the air. Chunks of rubble cut into the cable leading from the power truck, and the flow of current stopped; now the pumps could not be turned on, and freshwater could not cascade into the core. Other pieces of debris sliced into the fire engine hoses leading from the seawater pit. Smoke billowed upward, radiation levels soared, and the workers fled Fukushima’s first radioactive ruin. It wouldn’t be the last: The battle to contain the catastrophe during the first 24 hours was lost, and the explosions would keep coming.

If the explosion had not happened, it is likely the rest of the disaster would have been averted. They were making progress on cooling and stabilizing. How could the explosion have been avoided? A simple catalytic recombiner in the higher areas of the roof structure. (Or, one might suggest, a window biased open that is held closed by electromagnets…) Just having the electrical equipment control panels located on upper floors instead of in the basement. Generators located higher up slope, or in higher stories. Several specific ‘lessons learned’ are listed. Generators in places away from where water accumulates. Having systems intended to run without power manageable without power and with the ability to turn it on without power. Have standby power trucks close, not 250 km away (but not IN the likely disaster area…) Have independent and very secure batteries to power the instruments installed. Put in those H2 recombiners. Put filters on vents that do not need power to work (so if you need an emergency venting, you don’t need power to do it safely).

In other words, design more of the plant to be passively safe and not need electricity while making the electricity more disaster tolerant. And plan how to get rid of H2 from a core accident and / or spent fuel rod coolant failure. WITHOUT electric power…

It also looks like preventing accidental gas coupling between buildings is also important:

TEPCO reports say the problems in reactor 4 were probably due to hydrogen gas that leaked in from reactor 3; despite early reports to the contrary, the spent fuel rods stored in pools in reactors 4, 5, and 6 were covered with water throughout the accident and never posed a threat.

I’d also suggest that parking a half dozen nuclear reactors on the same chunk of sea shore in a Great Quake and tsunami region is not so bright on the face of it. Spread them out a bit more and put them up slope some more. Longer pipes to the ocean are not THAT expensive, considering the alternative of ‘fratricide’… I’d also suggest that maybe having some kevlar fire hoses and kevlar shielded power cables on those emergency trucks might be a good idea too.

The article also lists a main index article with more about Fukushima:


That link has about 9 other links on the top page. Several look interesting. From “Germany’s Nuclear Free Future” to “Aftermath of a Disaster Zone” to “China Remains Committed to Nuclear Power”. It is clear from the quality of the first article that those others are going to be information dense and prone to direct and honest evaluation of the facts.

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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13 Responses to Fukushima – IEEE Engineering Retrospective

  1. http://www.livescience.com/6328-ancient-supervolcano-created-giant-underwater-mountain-chain.html

    Shatsky Rise









    Some nice links to underwater volcanoes around the world (about 3million of them LOL)


    Just idiots for building reactors on the sea coast of japan. Maybe the West coast would have been better as less chance for tsunami.

    Interesting that Fuji has not done anything yet, as last time it awoke soon after.

    Aso Volcano is another massive volcano and there are some gigantic volcanic structures just off shore of Japan as well. Japan really reminds me of NZ

  2. Libertarian says:

    EM Idiocy knows no bounds. Several large companies, incl one I deal with, lost their nationwide networks in the Brisbane, Australia floods because their backup diesels were in basements below known repeat known flood levels.

  3. What a great post, this is excellent information, thanks!
    Re the engineering aspects of locating emergency generators in an area possible to be flooded – on the one hand it has been common practice which show many engineers/architects have overlooked this. Easy enough to be critical in hindsight.
    On the other hand, now that we have been thrust into reality, it does seem to be actually a culpable design deficiency, especially in this case where the basements are next to the ocean, and presumably are below sea-level.

  4. kuhnkat says:

    Interesting. Worse than I thought, but, not much. I keep hammering people with the FACT that 3 reactors melted down and little damaging radiation was released. I was under the misimpression that none of them completely melted down, but, it sounds like #1 got close if not fully!!

    As you and this report point out it would not be very difficult to redesign these units to be failsafe. Of course, why bother with the new pebble bed designs alread dealing with the issues and throium where we should be heading.

    Oh yeah, the other old designs in operation may benefit from what was learned there.

  5. John F. Hultquist says:

    I spent hours reading about Fukushima in the days following the earthquake. Many smart folks were guessing, usually quite correctly, as to what was going on and going wrong. I just read the report you linked to and it is confirmation of what I was reading at the time – with better detail and photos. It is sad that all this could have been prevented had these plants been upgraded as was suggested they do. Costs? Hindsight says the cost would have been small compared to not doing the upgrade.

    From that page a link to a wind power gap in Germany goes to a 2009 article.

    Meanwhile, there are also good intentions that go bad. Consider:

    In the USA, cantaloupes produced about 30 deaths from Listeriosis.

    And in Germany it was organic bean sprouts – 35 dead, 100 with severe kidney damage, and more than 3,200 ill.

  6. Ralph B says:

    Interesting report. I was put off by the excessive use of overly dramatic words. The reporter is not familiar with how BWR’s work and as always gets contamination and radiation mixed up. Maybe I quibble, but really the public’s misunderstanding comes when they read articles like this and think the reporter an expert.
    The reactor vessel has relief valves that open automatically (no power needed) and vent steam to the torus (big doughnut under the drywell (containment)) the torus is half full of water which quenches that steam. Normally there are pumps which take the water from the torus and pump it back to the reactor. In the US plants I worked they were steam driven (Terry turbines, mount on a motor cycle and go darn fast!) the valves could be operated manually but only as a last resort. The Japanese went for electric pumps. That to me is what did them in. In the US the emergency generators have all been mounted at or above ground level. There are several vital loads with battery banks (either 250 or 125 VDC) that run through motor generators or inverters. Usually good for 15 minutes at maximum load (that is the most critical time period to ensure safety systems activate. Typically they can last 4 hours or more the 10 minutes is very conservative.
    Anyway the drywell is only rated for 50psi or so. as soon as the zirc water reaction went on and no cooling happened I am sure the reliefs on the drywell opened venting hydrogen into the reactor building as the offgas system was down. The rest is history. We covered this pretty well back when it was happening and looks like we were pretty accurate.

    Wish I had more time to write an in depth critique but I am heading out will be back next week. If you are still interested in my viewpoint I would be happy to comply then

  7. George says:

    Still more people dead from Colorado cantaloupe and German sprouts.

  8. E.M.Smith says:

    @Ralph B:

    Any info related to the topic is welcome. I leave comments open indefinitely and sometimes you will see someone add something even months later. No worries.


    “Intelligence is limited by stupidity knows no bounds. -E.M.Smith”

    And in larger groups and governments, the average intelligence approaches the lower nodal point…

    @Ken McMurtry:

    Glad you liked it. Nice to have inside pictures and actual events described, rather than speculation and panic.


    Also, that these were about 40 year old designs and the newer stuff is already much better ought to also be recognized. We don’t need to ‘fix’ the non-passive design issues, we need to just build the already existing passive safe designs. (Though where fast retrofits could be done to existing plant, it ought to be…)

    Were it not for the ‘regulatory’ burden being so high as to make the new stuff prohibitive to build, I’m pretty sure this plant would have been replaced some time ago with much bigger, newer, and far safer modern plant and equipment…

    Regulation tends to ossify, and that’s a bad thing in a fast improving technology fields with known risks in old approaches.

    @George & John F. Hultquist:

    We’ll have reports of 10,000 dead from a single drought event and not bat an eye… yet a bit of radiation and everyone is in a panic. How many died IN THE TSUNAMI? We don’t even know how many 10s of Thousands or 100s of thousands. There are not enough records to even figure it out. Best we can do is guess. How many square kilometers of cities are just washed away and gone? How many contaminated with CHEMICAL contamination from all the stuff that got slopped around? Yet all the focus is on the relatively small area around the reactors that is ‘off limits’.

    BTW, the 10,000 in a drought was on the news crawler today. Didn’t catch the country… Yeah, impressed me so much I didn’t even notice what country and impressed the news editor so much they condemned it to the crawler… Probably this one:


    he drought and accompanying famine in East Africa continues to get worse: Three more regions of Somalia have been declared famine zones–defined as places where at least 20% of households face severe shortages and when more than 2 people in 10,000 die daily from hunger. Al Jazeera reports that 29,000 children have died from starvation in the past three months. In total 3.2 million people are in need of immediate humanitarian assistance. Behind all of this: The worst drought in 60 years. Delivering aid has been hindered due to the Islamist group al-Shabab controlling to worst affected areas; until very recently they have refused access to many aid organizations, and have denied that conditions of famine exist.

    So we have a disaster caused by religious bigotries and egos mixing with “God’s Will” causing 29,000 children to die (heck, even if over stated by a factor of 3 it is horrific) and it doesn’t even make it to the “News Reader”… Roughly 10,000 a month.

    One nuclear driven desalinization plant and some hydroponics and they all could live in relative plenty and luxury. But hey, we might have a nuclear accident and cause a few more cancers some day… maybe… Can’t have that.

    How humanity collectively can act as it does is a mystery to me. All I can do is point at it and toss rocks… But we’ve divided into 2 worlds, conceptually. Industrialized – who are now addicted to and totally dependent on ever advancing technology (and taking the sporadic industrial disaster, pollution disaster, or nuclear leaks) vs the ‘primitive 3rd world’ of living ‘green’ and close to the land (but taking the sporadic natural disasters and dealing with Malthusian LImits as nature presents them).

    Only time will tell which is more durable. One has a few million years of ‘working’ – with an equally long history of misery. The other has a few hundred years of spectacular successes and astounding quality of life; but has Malthus lurking in the background over the longer time scales… can we REALLY get a ‘soft landing’ of population growth with modernity?

    The contrasts between the two could not be more stark.

    And, what bothers me the most: I recognize that what is best for human survival is to have BOTH existing in the world for all of time. That way, if one fails, the other can replenish it… But that guarantees that someone is going to suffer who otherwise would not… Welcome to The Dismal Science…

    A necessary consequence of that context is that 10,000 children a MONTH can die in one place and we don’t even notice; while nearly nobody dies from a major nuclear accident in Japan and the entire Western World has fits of terror and rage… and changes $Trillions of energy plans and economic trajectories…

    Sometime I wonder about the insanity of people… the rest of the time I’m sure ;-)

  9. boballab says:


    If Uncle Joe Stalin was still alive he would probably say this: 1 hypothetical death is a tragedy, 29,000 real ones is only a statistic.

  10. Pascvaks says:

    Ahhhh.. “The Power of the Press”!! What you see and hear is all you get. What people are fed says a lot about who they are and what they think, we is what we eat y’know. If anyone actually thinks that the world has more problems now than it ever has, they’re bass’ackwards in their thinking, today we see and hear more than we ever have. On days when I’m really down, I have to do what people have always done, I have to get outside, get some fresh air, feel the breeze, look at the clouds, hear the rustle of the leaves in the wind, watch a squarrel or a bird, and forget about the problems of humans on the Third Rock from the Sun.

    Remember the “causes” of the recent Oz floods? How about NOLA and Katrina? Now we have Fukushima to add to the list of “Human Caused Disasters”. Sure seems the “regulators” we have that are supposed to be “taking care of all the little things so we don’t have a big bad problem” are about as efficient as the management and union leadership at Government Motors.

    Ma Dear Friends, I propose we alls go out and tar and feather us a lawyer or two just to get all this pent up hostility out of our po little minds. Are ya with me? Somebody bring a rope just in case we find a politician along the way.(SarcOnlyOffATinyBit)

    We don’t have to dig far to find the roots of the problem.

  11. Hamish McDougal says:

    Brilliant link, EM.

  12. Hamish McDougal says:

    Your comment
    “A necessary consequence of that context is that 10,000 children a MONTH can die in one place and we don’t even notice; while nearly nobody dies from a major nuclear accident in Japan and the entire Western World has fits of terror and rage… and changes $Trillions of energy plans and economic trajectories… ”
    is spot-on.
    ‘Nuff said.

  13. PaulID says:

    what are the three accidents they were talking about in the quote you gave? I know of 4 “major” accidents 2 of which involved loss of life the 2 none life threatening were three mile island and Fukushima the two deadly ones being Chernobyl and the only deadly accident in the U.S. at the I.N.L. west of where I live.

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