Fukushima nuclear power plant situation explained

I’ll try to explain this without having to go talk about Nuclear plant design. For non-science majors, I wrote “Fukushima nuclear power plant meltdown explained simply” on Blog Watch. This article is going to be a little more technical, but it still won’t be Physics major-level. Pardon its simplistic explanation.

The 2011 Sendai Earthquake was without a doubt the most powerful earthquake to hit Japan, as we have recorded it. People didn’t start keeping record until 1900, so you can imagine that there is vast amount of information that we do not know about. Fukushima started producing electricity in 1971. In February 2011, Japanese nuclear energy regulators gave it another 10 years to operate. Fukushima nuclear power plant was designed to take on an 8.2 earthquake. And the beauty of Japanese Engineering showed through how Fukushima successfully withstood a 9.0 Earthquake, and a 7 meter high tsunami.

Nuclear power plants are designed in such a way that there are cascading backups. And Fukushima had redundancy written all over it. Fukushima suffered what experts call, “Level 4 Nuclear Event Scale. In English, it means an accident has occured but without significant off-site risk. The accident involves a significant damage to the core such as a partial core meltdown, or an overexposure of one or more workers that may lead to death. It also means an off-site release of radiation dose, measured in millisieverts.

There are seven levels of Nuclear Event Scale. The highest is Level 7, which is a Chernobyl-level type of accident where a major level of radioactive material is released causing widespread health and environment problems.

What the Japanese are now doing at Fukushima is preventing a core meltdown. One Unit 1 of the reactor, they have already flooded it with SeaWater mixed with boron. This forces the Core from cooling down.

So what’s the status now? According to Brave New Climate:

“Unit 1: Seawater injection continues and it is thought the reactor core is now sufficiently cool. Safety regulators consider reactor pressure of 353 kPa an indication of a stable condition.

Unit 2: The normal reactor core isolation cooling system is in use. Fuel rods are covered by about 3.8 metres of water.

Unit 3: Operations to relieve pressure in the containment of Fukushima Daiichi 3 have taken place after the failure of a core coolant system. Seawater is being injected to make certain of core cooling. Malfunctions have hampered efforts but there are strong indications of stability.

What of the explosions? Here’s a bit technical explanation of the explosion:

“Gas pressure in steel reactor pressure vessel rises when coolant systems are not active and is vented to reactor building by engineers. {In my view there is not yet plausible evidence that the temperature of the PV water was sufficiently high to spontaneously split water}

j. The hydrogen in the reactor building is ignited in an explosion which blows out the walls but is not likely to have damaged Steel pressure vessel or concrete containment.

{this is true of both scenarios –but the source of the hydrogen is also external to the PV and containment in my explanation, overcoming the problem of why there was not a hydrogen explosion within the containment and outside the PV!}”

The problem really is that there are mixed-signals being given. World Nuclear News reports:
“The Japan Atomic Industry Forum (JAIF) reported back from a press conference given by the Nuclear and Industrial Safety Agency (NISA) at 11.30pm. The trade body said that a malfunctioning guage means that water levels cannot be confirmed. The gauge in question reads that water levels are around two metres below the top of the nuclear fuel assemblies, which would represent a very serious situation with the risk of fuel damage.

“It is unknown whether [the reading] is real or not,” said JAIF. Other readings from the reactor system do not indicate that the reading – and the associated potential damage to fuel – are the true situation. Pressure levels stand at around 250 kPa, compared to reference levels of 400 kPa – and a high of 840 kPa recorded at unit 1 yesterday. Radiation levels have dropped during the seawater injection, said NISA.”

The situation is serious, but manageable.

FAQ on the Japan Nuclear power plant situation.

Cocoy Dayao

Cocoy is the Chief Technology Officer of Lab Rats Technica, a Digital Consulting company that specialises in DevOps, iOS, and Web Apps, E-Commerce sites, Cybersecurity and Social Media consulting. He is a technology enthusiast, political junkie and social observer who enjoys a good cup of coffee, comic books, and tweets as @cocoy on twitter.

Cocoy is also the Managing Director and Editor-in-Chief of the ProPinoy Project.

Cocoy considers himself to be Liberal.

  • Karl

    Guys, the situation in Japan is extremely serious now. Start paying close attention because it may soon be a crisis for us as well.


    I am not optimistic about how the local government will disclose radiation reading within the country, but i fully expect them to minimize the their findings.

    Here’s a satellite link to help you gauge for yourselves how the winds are either in or out of our favor. With this site, you can visualize cloud and wind behavior at different altitudes if you look carefully.


    May God bless us, and let’s continue to pray for Japan. They are now in very grave danger.

  • Cocoy

    Earthquake thread with references to impact studies, and damage scenarios >> here.

  • Bert

    The toll on human casualty in Metro Manila will depend on whether the earthquake strikes during the day or during the night. A 40 floors office high rise building contain about 2,000 workers at a time, so, assuming that builders in Metro Manila did not strictly follow building codes requirements will surely result to more deaths if the quake strikes during working hours.

    What compounded the problem is that there is no way to tell whether a certain existing building can withstand what magnitude of an earthquake it can take until after the earthquake strikes.

  • UP nn grad

    Earthquake deaths in Haiti was much higher because many buildings were built/approved-for-habitation were actually not in compliance (e.g. usual concrete-posts with inadequate rebars or like what plagues Pilipinas highways — concrete-mixes have the cement-proportion not in compliance). What are the odds so many such buildings are interspersed around metro-Manila? Forget individual houses; more worrisome will be higher density structures like high-school and college buildings.

    • Karl

      Another important consideration is who will bear the costs to repair the massive damage to the infrastructure throughout metro manila. It will undoubtedly be slow going and run up in the billions of usd. With a significant quake, the aftermath scenario is equally forbidding. Economically, this country could get back up to speed quickly, but we will still need clean water and a means to get to work.

  • Karl

    Thank heavens this didn’t happen during the typhoon season. Pray that the winds don’t change.

    The situation could actually create business opportunities for the Philippines. For example, car makers here may be asked to ramp up production to make up for plant closures there. They still need parts from Japan, though.

    It will ultimately depend on the reactor resolution and which areas are deemed unlivable, if at all.

    Wind still majorly in our favor. Only place to buy potassium iodide is at mercury bambang. Tell them your having a nuclear medicine scan.

    • UP nn grad

      Fukushima reactor could have easily handled the Baguio-1990 earthquake. Baguio was 7.8-on-Richter; Fukushima is designed to shake off 7.9 earthquakes.

      Question — can Baguio now handle a 7.8-on-Richter earthquake? How many more 4-story to 8-story high school/college buildings/public buildings are there in metro-Manila like the CCP of Cabanatuan, flattened with 154 dead by Baguio-1990/7.8-Richter earthquake?

      Some enterprising student working for his Masters-Public Administration or MBA or MS-Operations Research should write a paper on the difference in building codes for Pilipinas between 1985 and 2010. Surely, the codes have been upgraded for 7.9-Richter and school-buildings have been retrofitted for 7.9. But one has to wonder if the codes are now for 8.3 or 8.4.

      • Cocoy


        You make a good point and that’s precisely some of the points being raised recently. Also some of the hoopla on where we are exactly regarding earthquake survivability. There were several papers published on the extent of the damage. In Manila for example, one worst case scenario the research papers came out with, some 33,000 people would die, and some 40 percent of infrastructure lost. We published the pdf several days ago here on propinoy.

        • Karl

          Japan was warned by the IAEA that it likely would not withstand any quake over 7.0


          I haven’t had the time to read the other earthquake post here nor am i a structural engineer, but from what i understand, subsurface materials are critical. Some areas of Manila are on adobe rock – vs. virtual bog-lands like MOA. Fault areas like Ortigas may have an influence on the ‘quality’ of the quake as well.

          If we think of safety in terms of business district locations, or places with large buildings, well these areas are probably operating on safer structural codes than 80 percent of the remaining metro manila. I think no matter how you forecast the damage, most residential areas will take a pretty bad hit.

          Been monitoring the winds today and they are less favorable, unfortunately.

  • UP nn grad

    There is also another crisis that is looming:

    South Korea is looking to build a strategic grain reserve and is planning to buy cargoes of corn and another staples, joining similar efforts by other Asian nations worried about high food prices and social unrest.

    In December, Mexico bought millions of tons of corn futures to guard against price hikes for tortillas that sparked street riots in 2007.

    “It is a rational thing to do, to cover yourself, Diouf said.

  • UP nn grad

    GMA-News-TV is suggesting that Malakanyang should ask Food Authorities, like Thailand, should testing food imports from Japan.

    BANGKOK — Thailand will randomly test imported Japanese food products for possible radiation contamination, the country’s Food and Drug Administration said, after Japan warned of more radiation leakage from a power plant.

    There have been four explosions at the plant in Fukushima, north of Tokyo, since it was damaged in last Friday’s massive earthquake.

    “We will give priority to fresh food and fresh produce including vegetables and fruit from Japan,” Pipat Yingsaree, secretary-general of the Food and Drug Administration, told Reuters on Tuesday.

  • karl

    Tokyo now reading between 3 to 22 times backround levels. looks like its working its way south.

    that is about 1 rem/year, ok for adults but not ideal for children, and not at a sustained rate. with reactor activity unpredictable, it will likely fluctuate for the next few days.

  • KG

    The will of the wind. 🙂
    Nice one namesake.

  • Karl

    Not good guys. They are evacuating staff from the plant. Nobody will be there to attempt to cool the cores. Looks like they’ll be left to melt down, all of them.

    The japanese president and other officials there don’t sound encouraging at all. Their dispositions are like they lost a war.

    Positive note: Winds totally in our favor

    • UP nn grad

      What a mess. I’d hate to be a Japanese reading anything whether it be Mainline Media like Reuters or blogsites reporting “…doncha worry, it’s only level-this or level-that” or others hollering for shutting down all nuclear plants.

      The big item helping Japan — an honest and disciplined population. No reports yet of looting of houses vacated by citizens fleeing in fear of radiation brought by the winds or in search of “safer areas”, safer to include water and food.

      • UP nn grad

        I still remember Hurricane Katrina, when some (a small minority) of the New Orleans citizens went for a week-vacation in Europe or in California when the words was sent out to vacate. Won’t be surprised if a small minority of tokyo residents are doing the same — accelerating their European or USA vacation schedules with word of ill-wind headed their way. Better safe (and enjoying the spring weather) than panicked over bad wind.

      • KG

        yes those traits (honesty,discipline,preparedness,calm under pressure,etc) of the Japanese continue to amaze me

  • Karl

    Nice post Cocoy. I woke up and was amazed to find out how rapidly the situation there has deteriorated. Official word is that the dome in reactor 2 has been compromised. Reactor 4 is now reportedly on fire as well. Exposure rates further south of the plant are starting to rise. That means, presumably, that gases are also working their way south already.

    One thing the public here needs to understand, is that the winds have been very favorable thus far. Unfortunately, that is the only reason why southern japan and the Philippines are not currently in a major crisis. We are literally at the mercy of the wind. Also, what we observe on satellite imagery may not say it all. There is still a significant possibility of danger for us so it might be a good idea for people to pay attention and be prepared rather than be blindsided and rely on the governments info.