There is now little doubt that Fukushima Reactor 3 experienced post-tsunami fission but it is leaking

The water within Reactor Number 3 (where three workers were exposed to high levels of radiation yesterday) is 10,000 times more radioactive than the average water inside a nuclear reactor and contains radioactive iodine that is generated during fission and has a half-life of 8 days. Japanese engineers are pretty sure that this means that fuel rods within the reactor have contributed to fission reactions.

Here’s an important bit: The physical container that holds the fuel rods inside the reactor is very robust and is probably not leaking. However, as you might guess, the reactor container has a number of holes in it for pipes (etc.) that communicate between the inside and outside of the container. The reactor vessel need not be ruptured or broken for stuff to get out. The engineers in Japan think that highly contaminated water probably exited from the reactor containment via these pipes, though they are not sure.

There will be those who will claim that this does not constitute a leak. But it is.

Reactor containers 1 and 2 are also leaking, according to the engineers.

Source: NHK live report. You can also check the IAEA site for updates.

Regarding the workers (from the IAEA site):

three workers at the Fukushima Daiichi nuclear power plant were exposed on 24 March to elevated levels of radiation. The IAEA has received additional information on the incident from the Japanese authorities.

The three were contracted workers laying cables in the turbine building of the Unit 3 reactor. Two of them were found to have radioactivity on their feet and legs.

These were washed in the attempt to remove radioactivity, but since there was a possibility of Beta-ray burning of the skin, the two were taken to the Fukushima University Hospital for examination and then transferred to Japan’s National Institute of Radiological Sciences for further examination. They are expected to be monitored for around four days.

It is thought that the workers ignored their dosimeters’ alarm believing it to be to be false and continued working with their feet in contaminated water.

The Nuclear and Industrial Safety Agency (NISA) of Japan instructed TEPCO to review the radiation control system immediately in order to avoid similar incidents in the future.

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37 thoughts on “There is now little doubt that Fukushima Reactor 3 experienced post-tsunami fission but it is leaking

  1. Javad: “I hope they can control the disaster as soon as possible.”

    I’m more cynical than most, Javad. I don’t believe the leadership at Tokyo Electric is composed of well-intentioned people. Their history is replete with denying problems, and disclaiming responsibility. Like many large corporations, they priortize image management (and dividends)over human lives. They won’t contain this, at all. I’m guessing the executives are still considering ways to convince the Japanese government to let them use reactors 5 and 6 (TEDCO needs to recoup these losses, after all).

    This will be contained when the prime minister has had enough of being played, and does what Michio Kaku said at the end of last week– sandbag the place, build the sarcophagus. Gorbachev was smart enough not to let the thing burn for another week.

  2. IIRC correctly the very high temperature of the water circulated around in within the reactor means that the pipes and welds are very susceptible to corrosion. Which is why the cooling water has to be very pure. They’ve been pumping seawater, not known for it’s lack of contaminants, into the reactor for almost two weeks. In fact these types of leaks were predicted as soon as they started using seawater.

    I’m also still very concerned about the state of the spent fuel ponds at reactors 3 and 4. There is almost certainly some damage to the fuel rods in those ponds. If the pools are damaged then the water they’re putting in is going to leach out radioactive elements which are definitely going to work their way into the groundwater and into the ocean.


  3. Zirconium is essentially completely resistant to chloride as long as the temperature is low enough that there is actually liquid water present. Zirconium alloys are not susceptible to stress corrosion cracking the way that stainless steel alloys are. You need pretty high stress levels and pretty high temperatures to get very rapid stress corrosion cracking of stainless steels. I don’t think there would be any significant stress corrosion cracking below 100 C.

    There might be some failures of small piping or tubing, failure of the reactor vessel by corrosion due to sea water is not likely. Melting fuel is another matter, but that is becoming less likely all the time (as the decay heat gets smaller).

    The danger for the fuel remains it getting too hot, above 400 C or so. Then it can oxidize catastrophically in air or steam and perforate. There is high pressure gas inside the fuel element (first high pressure He and later Xe and Kr add to that (radioactive of course)), so once the fuel element cladding weakens the element will leak. After it leaks, pressure fluctuations would drive water in and out and would remove non-gases too, like CsI.

  4. Darlene #4 The issue of â??worst case scenarioâ? reminds me of an episode I heard of when TMI was going down. A reporter asked that and the nuclear engineer said (paraphrasing): that the fuel would become uncovered, overheat and melt down and become hypercritical in the bottom of the reactor vessel. There would be an explosion that would breach the reactor vessel and the containment vessel and disperse the entire inventory of radioactivity in the core into the atmosphere. At that exact moment, a tornado would pass by and would pick up all the radioactivity of the core and that tornado would travel up and down the East coast depositing a lethal dose of radioactivity in each major population center.

    The reporter was not amused by the invoking of the tornado because that was â??so unlikelyâ? and said so to the engineer, to which the engineer replied, â??you didn’t ask me for the most likely scenario, you asked me for the worst case scenario, don’t complain to me when I give you what you ask for.â?

  5. Darlene, I am not a nuclear engineer, but I’ll take a stab at that because most of the actual nuclear engineers have drunk so much Kool Ade that they are not much use.

    The wost case scenarios that are not impossible but remain fairly unlikely involve a combination of uncontrolled fission (making things much hotter and creating a lot of extra radioactive stuff) and explosion so that radioactive material is spewed into the atmosphere and badly contaminates a large area. Assuming everyone is evacuated only plant workers would be at risk. Subsequently, farmers would be out of business for a significant amount of time while the radiation dissipates. It is hard to say how such an event would impact the marine environment.

    More likely than that is the scenario we see now and not a lot more: Modest to minor contamination of workers and maybe some other people, contaminated farm land but not too contaminated so maybe one cycle of crops is lost, and a very nasty mess at the plant itself that will take thirty to fifty years to clean up at great expense.

  6. Daedelus2U [5] I think you’re the only one here talking about Zirconium, but since you bring it up, I should tel luyou that Zirconium has already been confirmed as having been melted into the seawater in the plants, and the rods were in fact exposed to the air. The problem with seawater is that the outer cladding of the rods an become brittle in a way that keeps them intact until water is added later, then they fall apart and the fuel pellets all fall to the bottom of the container where they heat up the lower (never out of the water) rods which are not oxidized.

    There might be some failures of small piping or tubing, failure of the reactor vessel by corrosion due to sea water is not likely.

    Why are you arguing something that has already been stated?

    Melting fuel is another matter, but that is becoming less likely all the time (as the decay heat gets smaller).

    Both fission and melting seem to have already occurred. Hopefully it is settling donw.

    Daedalus2u: great example of NPA monkey waving. the part of that scenario prior to the tornado is in fact the WCS for a nuclear reactor. Adding the tornado is the monkey, waving.

  7. Asinine â??expertâ?? analyses of the day:


    Categoryâ?? â??Orwell got nuthinâ??, nuthin I sayâ??:

    â??Experts said the exposure Thursday was likely due to the continuing venting of steam from reactor vessels to relieve pressure and heat. They said such activity had no serious health consequences outside the 20-km (12-mile) evacuation zone.

    “It isn’t too surprising given the problems they have had,” said Ole Reistad, a senior expert at the Norwegian Radiation Protection Authority.

    “Getting water through the primary circuit is the fundamental function they need to maintain. But they need to be able to control the workers’ exposure.”

    He said the release could even be seen as positive if it meant workers had restored water circulation through the reactor pressure vessels after pumps were knocked out.�

    **The release of radioactive materials can be viewed as positive? Compared to what? Doing a round of Cesium shooters? Itâ??s a sign of desperation, Ole. Theyâ??ve been grasping at hallucinatory straws for 12 days, and youâ??re happy to swim in the pool of delusion.

    Categoryâ?? â??Not who I want in charge of safety and inspecting nuclear plantsâ??:

    “10,000 times sounds horrendous but it’s probably not really. But you wouldn’t want to wash your hands in it.” (Laurence Williams, professor of nuclear safety at the John Tyndall Institute for Nuclear Research in Britain and a former chief nuclear power plant inspector.)

    **Whatâ??s a few orders of magnitude of increased hazard between friends? Wouldnâ??t want to wash my hands in it? You donâ??t say, Larry. Or bathe at all, brush my teeth, or consume it in any form, or inhale it, or have it come into contact with my skin. You know, all those ridiculous things people are liable to do when foolish enough to go about their daily lives.

  8. The uranium fission was completely shut down before the tsunami hit. They may have lost precise control over the geometry of stuff inside the core because of melting and oxidation, but there is basically no uranium fission going on right now. The cesium and iodine were already there, inside the fuel rods, as a result of fission while the reactor was operating before the earthquake. Detecting these radioactive elements in the atmosphere proves that the fuel rods have been breached, somewhere and to some extent, but it does not necessarily mean that uranium fission is happening now.

  9. CherryBombSim, that is not what the engineers in Japan are saying. They are making the claim that there is too much short-lived radioisotopes that can only come from fission that happened since the plants were shut down to be explained any other way. Some of the radioisotopes have very short half-lives, and should be pretty much gone if they were created while the reactor was turned on. But one of these short lived isotopes is sufficiently abundant that it is most likely to have been produced by fission after the shut down. This implies that some fuel rods have shifted or, more likely fallen apart and some pellets are gathered up somewhere enough to reach criticality.

  10. Greg, do you have a link for the criticality claim? I have looked pretty hard and all I can find is the “neutron beam” report which I don’t find credible. It was 1.5 km away.

    I haven’t seen any reports of radioisotopes that look like fresh fission is going on. I see some reports that are on the verge of detection limits, but isotope identificationn is not so good at those low levels.

  11. I was referring to a presentation given by a TEPCO engineer on NHK World Television ( which has an ongoing neverending live report.

    Here is the NHK summary of that story:

    Japan’s nuclear safety agency says it is highly likely that radioactive materials are leaking from part of the Number 3 reactor of the troubled Fukushima Daiichi nuclear power plant.

    The Nuclear and Industrial Safety Agency spoke to reporters on Friday about an accident in which 3 workers were exposed to radiation in the turbine building of the No. 3 reactor.

    It said 3.9 million becquerels of radiation was detected from 1 cubic centimeter of water sampled from the floor of the building. The radiation level was about 10,000 times higher than the water inside a normally operating nuclear reactor.

    The agency said the water sample indicated it is highly likely the leak comes from the reactor itself, not from the pool storing spent nuclear fuel.

    According to the officials, pressure inside the reactor core is stable and the agency doesn’t believe the reactor is cracked or broken. But it says it is highly possible that radioactive materials are leaking from somewhere in the reactor.

    The agency also said high levels of radiation have been measured at reactors No. 1 and 2, and speculates there may also be leakage from them. Cooling operations using seawater are continuing at the reactors.

    The plant’s operator, Tokyo Electric Power Company, also known as TEPCO, resumed work to restore the external electricity supply to the facility on Friday morning.

    Engineers are now checking pumps and other equipment for malfunctions before hooking up reactors 1 through 4.

    Lighting is expected to be available in the control room of the No. 2 reactor on Friday, while at the No. 3 reactor firefighters continue spraying water at the fuel storage pool.

    TEPCO says it intends to switch over from pumping sea water to pumping fresh water into the 3 reactors, as salt in the sea water could cause corrosion and buildup, hampering the smooth flow of water inside the structures.
    The company has been pumping seawater as an emergency measure.

    The power company also says preparations to switch to fresh water were completed at the No.1 reactor on Friday afternoon.
    Operations to pump fresh water into reactors No.2 and No 3 are expected to start later in the day.

    Friday, March 25, 2011 18:54 +0900 (JST)


    but that does not give the details the engineer was giving in the live report.

    If you can open up this link you can see a tepco person talking:


    This is not the same thing I saw, however.

  12. Greg, I saw those. I132 has a half life of 2 hours, but it is the daughter product of Te132 which has a half life of 3 days. Every sample I saw that found I132 also had Te132. Because I132 has ~1/40 the half life, you would expect to see about the same activity of I132 if it is the daughter of Te132 (because the I132 decays as fast as it is formed relative to Te132). That is about what the levels show. If both were from fresh fission products you would expect to see much higher levels of I132 because it decays 40 times faster.

    I don’t take this as evidence of a criticality event shortly before these samples were taken. You would expect to see other isotopes that are not present. I135 for example, it has a half life of 6.7 hours, I133 has a half life of 21 hours. These are not the decay products of longer lived fission products. There absence indicates to me that these are not fresh fission products.

    If there was a criticality event in sea water, you would expect to see neutron activated sea water minerals. You should see chlorine 36, and maybe Na24 (but maybe not Na24). Chlorine 36 would be essentially proof of a criticality event, even at very low levels. There is some from background cosmic rays but that is very small.

  13. I’ve asked nuclear experts. It’s unlikely that there’s a sustained chain reaction.

    It’s normal to get SOME fission byproducts from a shutdown reactor, since fission happens naturally in uranium and they are amplified by all the fissionable fuel.

    Subcriticality just means that fission chain reactions are not self-sustaining, it doesn’t mean that they don’t happen at all.

  14. Alex, if that is the case (and you are conficting with daedalus2u here … I’ll let you two slug it out) then the radioisotope evidence does still point to material coming out of the reactor containment facility.

  15. @daedalus2u: Thanks for that explanation. What’s your take on the significant increase today of Iodine131 near discharge pipes (~1,250 times the control limit, up from the last reading of 140X)?

  16. I think an actual reactor vessel has a crack or hole in at least one unit.

    I base that upon the reports of Neutron Beams three days ago. My understanding is that for such a beam to occur there must be fission occurring within line-of-sight of the hole or crack. Criticality is unlikely except in the core, ergo the crack is within line-of-sight of the core and therefor probably in the main body of the reactor. If its at a pipe joint it must be immediately adjacent to the reactor’s main body. Or else fission is happening in the cooling pipes, that case would be even worse as it means the fuel has melted and left the main reactor vessel.

  17. Greg, yes, those fission products did escape from the reactor, how they did is not clear. Te is pretty volatile. The few isotopes I am not clear on is Co58. I think that is a reactor product, from neutron activated iron. That might be from corrosion of the steel vessel by sea water. Activation of Fe would make Co58, but that should be pretty non-volatile. The same with the Ba140 and La144. I can’t come up with a plausible scheme by which they could evaporate out. I think they are from leaking water from the reactor. The half lives are too short for them to be from the spent fuel pools.

    The design specs say the reactor vessel is low alloy steel clad on the inside with stainless steel (with special provision to use alloys not susceptible to stress corrosion cracking).

  18. So idiots invade every debate? Well, idiots have company and so do I. I am from the West Coast (where else?) and about a week after the Japan event I was outside for a few minutes. It was snowing the kind of heavy wet snow we sometimes get as spring approaches, but I thought nothing of it as the newspapers had said that there was no chance of radiation having reached the coast at that point, and that even ‘if’ it arrived, it would be so minimal as to be almost undetectable.
    Imagine my surprise when I got inside the house and the top of my head started to feel weird and tingly.
    ‘It’s your mind.’ I told myself. ‘The media says there is no chance of radiation even being here.’
    So I didn’t do anything sensible like take a shower and wash my hair, though the tingling sensation was so evident that I certainly should have. About 6 hours later, I thought, ‘Well, it may not be radiation, but it’s some damn thing.’ And I did take a shower. The reason I’m writing this is that the unusual, tingling sensation is still there, about a week later.
    It could be that I am reading too many stories about farms in Germany where the soil is still unsafe, and lakes in Sweden where it is not advisable to fish or swim – 25 years after Chernobyl. All I know is that the tingling is still there and that if it doesn’t go away I may give up on science, buy myself a turban and a few tea leaves and go on the carnival circuit as some kind of radio-active fortune teller. I don’t want to; I hate fairs and don’t much care for the people who attend them, but what else will be left to me as my rational mind slips into the ether? And no, the radiation didn’t give me any special powers, not even the ability of many politicians and journalists and industry execs and whacko religions (all of them) and even whole countries to make the completely unpalatable sound like exactly the kind of horse shit you have been just dying to support with your tax dollars.

    Luckily, fortune tellers only have to tell the kind of lies you want to hear: Unlucky in love? I see a 22 yr old blonde model in your future! (She’s in your bedroom closet under the spare sheets) Short of cash? Let me look deeper into the glass… ah! Definite signs of prosperity for you in medium terms. (shall I ask ‘Mad Doffer’ the infallibly psychic parrot to peck a few stocks for you?) Like to talk to your mother? no.. But I digress.
    Could anyone answer the question – Have I been exposed to an unhealthy dose of radiation from standing in that wet snow on or about March 19?

  19. I133 only shows up one day, March 19. That is the same sample that also shows Ru105 which is another very short half life (4.4 hr) species without a longer lived precursor. That may be a sign of some fissioning, but it is at the limits of detection. Ru105 and I133 give off a bunch of different energy betas and picking out the right energy ones might be tricky at the limits of detection.

    I think the â??neutron beamâ? is a bad translation. Neutrons would travel line-of-sight until they scatter off of something and then they become isotropic. It doesn’t take very much hydrogen to scatter neutrons. In air, fission neutrons have a mean free path of about 100 meters. Moderated neutrons (thermal) have a much shorter path of about 20 meters. Any kind of neutron beam that traveled 1 km is not credible.

  20. wath, it is extremely unlikely that your symptoms are due to radioactive contamination. Levels that would produce acute effects in minutes would probably be enough to cause serious harm over several days, i.e. wounds in the scalp that penetrate to the skull and that do not heal.

    In any case, the brain is quite resistant to radiation, so if that is all that got exposed you are probably ok. 😉

  21. Greg Laden:

    I’m not saying that there is significant amount of fission. I’m just saying that fission byproducts can be detected even with a shutdown reactor, though normally at minute quantities.

    Whether this is the case here I just don’t know.

  22. The spent fuel rods in the Mark 1 reactors are stored at the top of the building under the roof- which was BLOWN off in the first few days. This thing has been an censored level 8 diaster since nearly DAY 1. Where is the world to help?

    Black smoke billowing out is BAD NEWS. There is very little to burn inside at this point but the nuclear fuel itself. The northern hemisphere is being radiated. Agenda 21 at work, depopulation afoot.

  23. @Graciana
    May I pass you a tinfoil hat?
    The kids and I had much fun makin it, but I don’t think I’ve got much use for it.

    Now, back to sanity
    I believe…
    My knowledge about all those pretty isotopes is much too small to follow your discourse and basically, that discourse is based on the information we’re given by authorities that have done a bad job on that level since day 1.
    I think if I had a bug for every time they said that cores had meldted down, hadn’t melted, partially melted, probably melted, probably not melted, rods had breached, not breached, definetly no damage, possibly some damage, probably no damage and so on, I’d be rich.

    The only thing I think is very clear is that Tepco are money greedy assholes without a bit of conscience. Blaming the injuries of the workers on themselves is despictable. They claim that all their employees are free to leave, but this doesn’t apply to the employees of sub-contracted companies for whom those workers work.

  24. Jct: Right, the whole planet is going to be poisoned by it. Deadly Deceit is a great book detailing the death statistics after Chernobyl and other nuclear accidents which government acted upon by discontinuing the death statistics! Har har har. I’m doing a video on what I’m doing to protect myself.

  25. I just want to thank you guys for your informed comments – seem to be a few unnecessary comments getting posted which are clouding the discussion a bit for those of us who prefer not to comment on things we know nothing about.

    Just wondering about Ana’s question to daedalus2u about the appearance of Iodine131. I noticed in being bandied about elsewhere, as though it spelt the end of the world or something. Is it significant?

  26. Rodger, as TH implies, the issue here is that this radioisotope is short lived, and is generated through fission, so if it is spiking than there is fission going on somewhere.

    Not the end of the world, maybe not even a big deal. But it would indicate that some nuclear material has gotten where it should not be and that can complicate things. Or, maybe it will be a big deal. If someone tells you that it is NOT a big deal for sure, or that it IS a big deal for sure, that is their politics talking. We simply don’t know.

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