Jeffrey LewisAnother FEPC Statement

Another statement from FEPC.

My comment: TEPCO is fighting the good fight, continuing to inject seawater into Units 1 and 2.  TEPCO has suspended seawater injection on Unit 3 after the explosion. That looks very bad.  Remember, the goal now is to prevent breaching of the primary containment vessels.  There also remains an outstanding question about the status of spent fuel rods in cooling ponds.

I think we should avoid throwing stones at right now.  There will be plenty of time to assign blame later.  Right now, we should all be rooting for TEPCO to gain the upper hand.

Update to Information Sheet Regarding the Tohoku Earthquake

The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office

As of 1:00PM (EST), March 14, 2011

  • Radiation Levels
    • At 9:37AM (JST) on March 14, a radiation level of 3130 micro sievert was recorded at the Fukushima Daiichi Nuclear Power Station.
    • At 10:35AM on March 14, a radiation level of 326 micro sievert was recorded at the Fukushima Daiichi Nuclear Power Station.
    • Most recently, at 2:30PM on March 14, a radiation level of 231 micro sievert was recorded at Fukushima Daiichi Nuclear Power Station.
  • Fukushima Daiichi Unit 1 reactor
    • As of 12:00AM on March 15, the injection of seawater continues into the primary containment vessel.
  • Fukushima Daiichi Unit 2 reactor
    • At 12:00PM on March 14, in response to lower water levels, TEPCO began preparations for injecting seawater into the reactor core.
    • At 5:16PM on March 14, the water level in the reactor core covered the top of the fuel rods.
    • At 6:20PM on March 14, TEPCO began to inject seawater into the reactor core.
    • For a short time around 6:22PM on March 14, the water level inside the reactor core fell below the lower measuring range of the gauge.  As a result, TEPCO believes that the fuel rods in the reactor core might have been fully exposed.
    • At 7:54PM on March 14, engineers confirmed that the gauge recorded the injection of seawater into the reactor core.
    • At 8:37PM on March 14, in order to alleviate the buildup of pressure, slightly radioactive vapor, that posed no health threat, was passed through a filtration system and emitted outside via a ventilation stack from Fukushima Daiichi Unit 2 reactor vessel.
  • Fukushima Daiichi Unit 3 reactor
    • At 11:01AM on March 14, an explosion occurred at Fukushima Daiichi Unit 3 reactor damaging the roof of the secondary containment building. Caused by the interaction of hydrogen and oxygen vapor, in a fashion to Unit 1 reactor, the explosion did not damage the primary containment vessel or the reactor core.
    • As of 12:38AM (JST) on March 15, the injection of seawater has been suspended.
  • Fukushima Daini Unit 1 reactor
    • As of 1:24AM on March 14, TEPCO commenced the cooling process after the pumping system was restored.
    • At 10:15AM on March 14, TEPCO confirmed that the average water temperature held constant below 212 degrees Fahrenheit.
  • Fukushima Daini Unit 2 reactor
    • At 7:13AM on March 14, TEPCO commenced the cooling process.
    • As of 3:52PM on March 14, the cooling function was restored and the core temperature was stabilized below 212 degrees Fahrenheit.
  • Fukushima Daini Unit 3 reactor
    • As of 12:15PM on March 13, reactor has been cooled down and stabilized.
  • Fukushima Daini Unit 4 reactor
    • At 3:42PM on March 14, cooling of the reactor commenced, with TEPCO engineers working to achieve cold shutdown.


  1. JT (History)

    Seawater activation products? Seems to me the introduction of massive amounts of seawater to the core has its own complications. We should now be looking for short-lived Na-24 and long-lived Cl-36 in explosion plumes, in addition to fission products and actinides….

    • yousaf (History)

      I am physicist not an engineer so excuse the naivete: is there anything besides water that could viably be used as coolant?

      It seems the water may create more heat in exothermic oxidation reactions with the hot cladding(?) leading to more heat and more evaporation.

      I am sure it is more complicated than that but if anyone has insight on this, pls let me know.


    • Michael F (History)

      Not sure we’d see much in the way of activated impurities in the sewater – unless the corium at the bottom of the pressure vessel goes critical (which is doubtful with all the boron they’ve pumped in, but we just don’t know). We’ll know if the pressure vessel and containment is breached (not just venting) by a spike and then sustained release of not just I-131 and Cs-137, but a host of other fission products as well.

      Seawater is not good on piping and other materials. After this is stabilized they’ll probably run it for a few months to cool it fully down, but afterwards (and I am speculating wildly here) either let it evaporate and begin flushing with pure water or maybe just concrete over the whole thing and entomb it.

    • virtualnomad (History)

      Didn’t the Russians originally want to tunnel beneath Chernobyl to induce a nitrogen freeze? Of course, they eventually opted to entomb.

    • John Schilling (History)

      JT – There is no actual nuclear fission taking place at Fukushima. If it didn’t cease when the reactors were shut down after the quake, the boric acid certainly put an end to that. Plenty of radioactive decay, now and for some time to come, but radioactive decay doesn’t produce neutrons so it won’t activate the Na or Cl (or H or O) in the sea water.

      As the #1 and #3 cores at least have been damaged, we do have to worry about hot salt water leaching fission products and/or unburnt fuel from the fuel elements. That is presumably where the Cesium, etc are coming from.

      Yousaf – in principle, there are many coolants that could be used. But they will need to be used in substantial quantity, as there is ~10 megawatts of waste heat to deal with. Given the severly damaged infrastructure in Sendai, I suspect a steady supply of e.g. liquid nitrogen is not realistic.

    • yousaf (History)

      thanks — it just seems H2O is asking for trouble: more heat production, more hydrogen release. Especially since the hydrogen accumulates in the top of the structure near the spent fuel storage pools which have several years’ worth of spent fuel in them. That is a location you would not want a hydrogen explosion — of course, it appears to have happened in #1 and #3.

      If those explosions blew out the plumbing for the storage pools then we may potentially have a worse outcome than a meltdown.

      I fear that these hydrogen explosions are being taken too lightly given their location (i.e. approx. co-located with the spent fuel pools).

      If there is anything besides H2O that could be used it would be sensible to use it.

      But I take your point that the huge amount of heat to be absorbed requires the flow of an abundant cheap material.

    • Hairs (History)


      In an earlier thread I mentioned the reactor thermal power after shutdown, but unfortunately I used a total core mass instead of the fuel mass so I greatly over-estimated the thermal power. However, having woken up and drunk some coffee, some better estimates of Fukushima’s thermal power after shutdown (assuming 100 tonnes of uranium in the core) are:

      After 24 hours = 28 MWth
      72h = 21 MWth
      120h = 18 MWth
      168h = 17 MWth
      720h = 11 MWth

      Assuming they’re maintaining a pressure of 6 bar abs in the vessel then the evaporation of water will absorb heat at a rate of about 2,100 kJ/kg, thus the evaporation rates (and consequently the feed rates) necessary just to stop the core temperature rising are about:

      24h = 13kg/s
      72h = 10 kg/s
      120h = 9 kg/s
      168h = 8 kg/s
      720h = 5 kg/s

      In other words, in the first day you’ve got to pump in around 47 tonnes of water per hour, only falling to 18 tonnes per hour even after one month. At these rates there’s really no alternative to water: it’s readily available in vast quantities from out the sea (though sadly limited by the pumping capacity), it’s non-toxic, and importantly it has an enormous cooling effect compared to almost anything else. An equally important factor is that the plant was designed for water, so there are no significant unknowns with regard to water’s neutronic effects on the core, and also the existing equipment can handle it (pumps and valves would probably fail to work properly with any fluid that is significantly more or less dense, or viscous, than water; for example seal cooling would rapidly fail if another liquid were used after which the pump would just overheat and seize).

      As I’ve mentioned, there’s really no alternative to water. The fact that it generates hydrogen if the zircaloy gets hot enough is a major hazard, and I’m sure the Japanese engineers are racing to get power to their hydrogen igniters / recombiners to reduce this danger.

  2. gbettanini (History)

    Thanks for your interesting post, but i don’t fully unterstand the reactor n.2 cooling process.
    Seawater is injected in the core to cover the fuel rods, so i presume that the water pressure must be at around 80 atm, maybe more…. So the problem of the water level can be (and maybe already is) resolved.
    But after the water refill i don’t understand how the excess heat will be removed. Will the reactor vessel be sprayed with water? Is there some water recirculation with some heat exchanger? Will the second containment be flooded with fresh water and will hot (and radioactive) water extracted?
    I think that a thermal power of around 10 MW must be extracted to mantain a constant temperature in the core. In your opinion how could be the excess heat removed?

    • Jeffrey (History)

      They keep venting the core. It is called “feed and bleed” — one of the many terrible things I have learned this week.

    • Michael F (History)

      The core has been depressurized during the venting, as Jeffrey stated. I’ll try and dig up the reference for where they are, but I think they were down to ~25atm.

      After the water refill they are hoping to get temporary heat exchangers back up. This has been hampered by the damage from the tsunami to the switchyard.

    • gbettanini (History)

      Thanks, that explains an actual pressure of only 0,65 MPa. The actual pressure is far lower than the nominal pressure because (i presume) the water injection pump is weak.

    • Hairs (History)


      The lower pressure MAY be because the pumping discharge pressure is limited. But I suspect there would also be a deliberate policy to maintain a vessel pressure well below the normal operating pressure. I can think of at least three reasons for this:

      1. The enthalpy of vaporisation of water is greater at lower pressures i.e. at 6 bar abs it takes about 2,080 kJ/kg to evaporate water but at 75 bar abs it takes just 1,470 kJ/kg. Thus by running at a lower pressure each kilogramme of evaporated water is carrying away an additional 610 kJ/kg of heat from the core. Given the current problems this additional cooling effect at lower pressure is surely a major factor in the engineers’ thinking.

      2. If the cooling / water supply is interrupted while at 6 bar then there is a useful time buffer while the pressure rises towards the pressure vessel’s failure point. However, if the pressure starts at 75 bar then that buffer is reduced.

      3. The pumps are almost certainly centrifugal, and these deliver lower flows at higher pressures. Since flow is everything right now, it would make sense to run the pump at the lowest possible pressure (i.e. keep the vessel at the lowest possible pressure) in order to make most use of the pump’s / pumps’ flow capacity.

      I suppose there is also a another consideration, which is that if things got bad enough for molten corium to reduce the integrity of the pressure vessel, then a rupture from 6 bar would be less damaging (in explosive terms) than a rupture from 75 bar.

    • gbettanini (History)

      Very good points Hairs, thanks.
      So, to cover with liquid water the fuel assemblies the water temperature must be kept at around 160°C (320 °F).
      A nightmare.

    • Hairs (History)


      “So, to cover with liquid water the fuel assemblies the water temperature must be kept at around 160°C (320 °F).”

      Yes (and no). To keep the fuel assemblies covered under current conditions of about 6 bar abs the water temperature must be kept below 160 deg C, or alternatively the evaporated water must be replaced.

      If the water temperature rises above 160 deg C it won’t mean that the fuel assemblies immediately dry out; instead more water will evaporate and a new, higher pressure will be established in the pressure vessel. At this higher pressure the water’s boiling temperature will also be higher so there’d be a new equilibrium at which the temperature is maintained by allowing the water to boil off at, say, 170 deg C (= 7.9 bar abs pressure in case you’re wondering). If there’s still insufficient water in-flow then up the the temperature goes again, and with it the pressure, to a new equilibrium.

      Obviously the process does not really occur stepwise but is instead a smooth progression.

      P.S. I hope this wasn’t a patronising post – I’d assumed from your comment that the rise in saturation temperature and pressure (and its implications) wasn’t clear to you; please do accept my apologies if I’m explaining something you already knew.

    • gbettanini (History)

      No, far from patronising….. the rise and fall of pressure and temperature is clear to me but yesterday i was picturing in my mind a reactor kept at around 100 bar (water temperature 300+°C) vented now and then and refilled with pressurized water BUT with some kind of thermal exchange with the outer ambient.
      You and Jeffrey changed that picture quite a lot. A reactor cooled only through water evaporation enthalpy that (considering a 50 m3 water volume) you must fill and vent every three minutes.

  3. Virtualnomad (History)

    Sea water pumping in units 1 and 3 were suspended because the ONLY pump had to be rushed to unit 2. What’s up with that? IAEA says Japan’s having a hard time getting additional pumps into place. I understand that it must be a logistical nightmare. At the same time, isn’t there a U.S. aircraft group offshore with air assets? Can’t somebody fly the goods in with a helo? This seems very strange to me.

    • Eve (History)

      Perhaps the other pumps were damaged in the tsunami.
      Consider the foreground damage indicated here…note the damage to what appears to be turbines in the foreground.
      You will also see one of the loading bay doors on the building tending the reactor hall 4 damaged to approximately 3-4 metres up.

    • virtualnomad (History)

      Thanks Eve. I guess my point was that in terms of disaster mitigation, it would seem helpful to have other standby pumps either on or off site. Preferably both. Since they’ve shifted the mechanism to concentrate on unit-2, i’m assuming they’re somewhat mobile.

  4. Joshua Simeon Narins (History)

    I know next to nothing.

    What happens to all the seawater pumped into the reactor? Do unhealthily radioactive particles accumulate within it (i.e. does it get tainted by its proximity to the core, or is there just too much water for that to be an issue)?

    If it does get tainted, where/how/does it exit the reactor?

    • virtualnomad (History)

      The sea water is currently being “retained” by TEPCO. According to IAEA, TEPCO hasn’t determined what long-term storage options are. A yet unwritten story…

    • John Schilling (History)

      The sea water that doesn’t boil is being retained, and can be dealt with later. The cores are hot enough that some of the sea water does boil, which is actually where most of the cooling effect comes from. The condensers which used to take care of that are now just scrap metal. The steam is vented to the air, with whatever radioactive contamination it managed to leach from the core along the way.

      Not enough to produce a Glowing Death Plume, but enough to raise concern. Dose rates of 2-300 uSv/hr were mentioned, which won’t cause acute radiation sickness but can lead to elevated cancer rates later on.

    • virtualnomad (History)

      40 uSv/hour in two kilometer radius, according to IAEA — down from from 1,000 uSV/DAY at peak melt. 0.02 uSV/hour is background

    • Hairs (History)


      The seawater is going to get very nasty – the continuous evaporation will mean that the remaining brine is concentrating extremely quickly. In the long term this will cause corrosion of the fuel cladding, and the chlorides in particular will be attacking all the austenitic steels in the core with a vengeance. More worrying in the short-term, though, is the build-up of scale.

      At temperatures above about 90 – 100 deg C there’s a strong precipitation of alkaline scales such as calcium carbonate and magnesium hydroxide from seawater. For this reason multi-stage flash thermal desalination plants use prodigious quantities of anti-scalant to try to keep their heat exchangers clean, and even then there’s typically a loss of heat transfer coefficient by a factor of 2 or so (this despite yearly acid cleaning to remove the scale that does form). Above 120 – 130 deg C non-alkaline scales such as calcium sulphate are deposited – and because these are such bitches to get rid of no multi-stage flash desalination plant will operate at a top brine temperature above about 110 deg C.

      At 6 bar abs the brine in Fukshima will have a saturation temperature of 159 deg C, so the brine in these cores will be depositing scale like crazy, and this will have a huge impact on the heat transfer from the core. To my (limited) knowledge the nuclear industry has never considered or calculated the effects of using seawater in such circumstances, so I’m willing to bet that the engineers in Japan had not reckoned on the effect of the scaling. Even if they had there was not much choice about the use of seawater. Consequently if the seawater is not being as successful as hoped it is probably because the deposited scale is cutting the heat transfer from the fuel to the water by a factor of 2 – 10.

  5. Red_Blue (History)

    Updated pictures (same as from ISIS, but from the source at higher resolution without any arrows obscuring the reactors) showing damage to reactor 3 (the one with two columns of steam:

  6. virtualnomad (History)


    40 uSv/hour in two kilometer radius, according to IAEA — down from from 1,000 uSV/DAY at peak melt. 0.3 uSV/hour is background

    • Red_Blue (History)

      The highest reading from today (probably from inside the plant) was 3,130 µS/h (over three thousand microsieverts per hour) as reported by Kyodo sourcing TEPCO, timed 9:37 p.m.

      NISA reported this as the highest measurement from plant boundary:
      “MP3 (Monitoring at North West of Site Boundary for Unit 2): 231.1 micro Sv/h (14:30 March 14)”

      I haven’t seen any per day measurements.

  7. Rip (History)

    CNN continues to hype headlines…”Is U.S. in Danger?”

    OMG! The cores are going to melt thru the earth and pop-out in Newark, NJ.

    • Andrew Tubbiolo (History)

      With all the exotic chemicals in the Passaic River the added heat capacity might help quench those runaway reactors. Not to mention they might be a welcome addition to the scenic architecture as seen from the NJ Turnpike. Sorry to any NJ natives out there. I defected from NJ during the Regan admin, and have fond memories of unique landscape that is Secaucus and Newark. Oh the pain when your coming of age years follow the course and dark humor of a Billy Joel song.

    • FSB (History)

      There may be legitimate danger — not just to NJ –if the spent fuel pools dry up and the winds carry the crap across the globe.

      In NJ, it would just add to background noise.

  8. CaptainCanuck (History)

    Some very interesting tidbits in a video released by the IAEA, showing Amano getting briefed on the Incident and Emergency Center (IEC):

    Freeze the video at 0:48 – appears they are modeling atmospheric propagation from Fukushima.

    Freeze the video at 0:54 – you can read the questions being posed by the IEC to (presumably) TEPCO.

  9. FSB (History);=&scp=5&%2334;spent%20fuel=&pagewanted=print

    “In both cases, the concrete primary containment shell was not damaged, officials reported. However there have been no reports of what happened to metal tanks at the top of the secondary containment building that contains the spent fuel rods, which continue to give off heat and must be cooled by circulating water, Lochbaum said.

    “One of the challenges is that the explosion took the roof away. If any of it fell into the [spent fuel] pool, it could either have damaged the fuel,” or impaired the water circulation in the pool. “That’s the concern that’s in play,” Lochbaum said Sunday. “

  10. tokyo requiem (History)

    NHK is now reporting that there is likely to be damage to the containment shell, in addition to the fuel rods that we already knew about.

    This is very bad, right?

  11. Red_Blue (History)

    This time the explosion (reactor 2) apparently didn’t damage the steel crane hall structure of the reactor building, but compromised the suppression pool and as such the containment of the reactor. Radiation readings have climbed sharply, now already 8,217 uSv/h at the gate. There are also reports on NHK World (TV) that “visible steam” has been leaking from reactor 2 for two hours and that staff is being evacuated except a team of 50 (per plant or per reactor?).

    In any case a very small number. When they gave an evacuation order before reactor 3 explosion, they soon recalled those not injured in the reactor 3 explosion.

    What’s strange is that there is still no information about the spent fuel storage pools on high floors of the damaged reactor buildings, nor about the refueling schedule of these reactors. Each building being damaged by explosions increases the risk that the reactor with the most recent refueling and hottest spent fuel rods, will also soon suffer from a spent fuel rod fire…

    • yousaf (History)

      This is from rwendland from a previous thread:

      Storage March_2010_amount Capacity

      At_reactors 3450 8310
      Common_pool 6291 6840
      Dry_cask 408 408

      Much of the spent fuel evidently is at the reactors

    • Red_Blue (History)

      This report dated March 2010 indicates that at that date, 3,450 fuel assemblies were in the reactor unit integral spent fuel pools, which represents 1/6 of average core capacity per reactor stored next to each reactor.

      However, at that date the common (external building) pool was near capacity, so if any refuelings have happened during 2010, it’s probable that the load in the itegral pool for that reactor may have increased somewhat.

      The big question is still which reactor refueled last, hopefully it was one of the units stopped for maintenance, but that’s not very likely unless something went wrong with optimal scheduling.

  12. FSB (History)

    Third explosion:

    “Chief Cabinet Secretary Yukio Edano told reporters the suppression pool of the number-two nuclear reactor appeared to have been damaged.

    This is the bottom part of the container, which holds water used to cool it down and control air pressure inside. ”

    If Amano says its ok, it probably is not:

    “Yukiya Amano, director general of the IAEA, said it was “very unlikely” to turn into an accident similar to Chernobyl as “the design is different and the structure is different”, making the reactors far safer. But local residents remained distrustful of official assurances, following accusations of cover-ups in the past. ”


    “Government officials admitted that it was “highly likely” the fuel rods in three separate reactors had started to melt despite repeated efforts to cool them with sea water. Safety officials said they could not rule out a full meltdown as workers struggled to keep temperatures under control in the cores of the reactors.

    The Fukushima crisis now rates as a more serious accident than the partial meltdown at Three Mile Island in the US in 1979, and is second only to the 1986 Chernobyl disaster, according to the French nuclear safety authority. After insisting for three days that the situation was under control, Japan urgently appealed to US and UN nuclear experts for technical help on preventing white-hot fuel rods melting. ”


  13. Anon (History)

    The governor of Tokyo, Shintaro Ishihara, had described the disaster as a “punishment from heaven” because the Japanese had become greedy.

    How come America was not punished??

  14. tokyo requiem (History)

    NHK is reporting that the spent fuel rods in unit one are exposed to the open air from the first explosion, and it is possible (likely?) that the cooling mechanism associated with the pool is not functioning.

    • Anon (History)

      Can you give a source or any more details?

  15. Ayu (History)
  16. Anon (History)

    “A spokesman for the Japanese company that runs the stricken reactors said in an interview on Monday that the spent fuel at the Fukushima Daiichi and Daini plants had been left uncooled since shortly after the quake.

    Some scientists said that a worst-case outcome was unlikely and that the Japanese would probably have enough time to act before too much water boiled away. Firefighters with hoses can pour in water, they said, or helicopters could drop tons of water.

    “I’m still hopeful that they can contain all this,” Thomas B. Cochran, a senior scientist in the nuclear program of the Natural Resources Defense Council, a private group in Washington, said in an interview.


    • FSB (History)

      “Mr. Shiomi of Tokyo Electric said that in addition to the power and cooling failures, some water had spilled from the pools.

      But he said that the company thought there “was relatively little danger that temperatures would rise.”

      “If you compare this to everything that’s been going on,” Mr. Shiomi said, “it’s not serious.”


      Everything is “bon” — Team America

    • FSB (History)

      “Fears also mounted about the threat posed by the pools of water where years of spent fuel rods are stored.

      At the 40-year-old Fukushima Daiichi Unit 1, where an explosion Saturday destroyed a building housing the reactor, the spent-fuel pool, in accordance with General Electric’s design, is placed above the reactor. Tokyo Electric said it was trying to figure out how to maintain water levels in the pools, indicating that the normal safety systems there had failed too.

      Failure to keep adequate water levels in a pool would lead to a catastrophic fire, said nuclear experts, some of whom think Unit 1’s pool might now be outside.

      “That would be like Chernobyl on steroids,” said Arnie
      Gundersen, a nuclear engineer at Fairewinds Associates Inc. and a member of the public oversight panel for the Vermont Yankee nuclear plant, which is identical to Fukushima Daiichi Unit 1″

    • archjr (History)

      FSB: Have some oatmeal. Does a great job on smugness.

  17. tokyo requiem (History)

    The Chief Cabinet Secretary Edano Yukio has right now announced at a press conference that there is a fire at the No.4 unit. As someone above predicted, it is caused by the spend fuel rods, which are no longer being cooled.

    The presser is being streamed live on NHK (Japanese only). I’m sure they’re be running the reel, and commentary, over and over again. You can watch here:

  18. yousaf (History)

    From the NHK (translated), I understood that there is a fire in the building of #4 reactor, but not at the spent fuel pool.

    Do Japanese native speakers have a different take?

    • adamk (History)

      From what I have heard the #4 reactor fire was put out, which would suggest it was not a spent fuel pool fire. Have not found a good live feed of events taking place at the reactor though, besides nhk-world.

      Under worst case scenario are there any procedures left on the table that could avert further catastrophe?

  19. Stephen (History)

    Does anyone know of any wonkish nuclear engineering blogger following this?

    I’m finding the MSM to be really unsatisfactory.

  20. Dan (History)

    Aren’t they going to run out of workers soon? If radiation continues to get worse, it seems like they’ll need to abandon ship sometime.

  21. Dan (History)

    From the IAEA (
    Japan Earthquake Update (15 March 2011, 06:15 CET)

    Japanese authorities informed the IAEA that there has been an explosion at the Unit 2 reactor at the Fukushima Daiichi plant. The explosion occurred at around 06:20 on 15 March local Japan time.

    Japanese authorities also today informed the IAEA at 04:50 CET that the spent fuel storage pond at the Unit 4 reactor of the Fukushima Daiichi nuclear power plant is on fire and radioactivity is being released directly into the atmosphere.

    Dose rates of up to 400 millisievert per hour have been reported at the site. The Japanese authorities are saying that there is a possibility that the fire was caused by a hydrogen explosion.

    The IAEA is seeking further information on these developments.

    The IAEA continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.

  22. Eve (History)

    Apparently all the fuel rods in reactor 4 before the inspection, is in the spent fuel storage pond, now without coolant and possibly exposed to air. Similar scenarios can occur in reactor halls 5 and 6.

  23. CaptainCanuck (History)

    Some very interesting tidbits in a video released by the IAEA, showing Amano getting briefed on the Incident and Emergency Center (IEC):

    Freeze the video at 0:48 – appears they are modeling atmospheric propagation from Fukushima.

    Freeze the video at 0:54 – you can read the questions being posed by the IEC to (presumably) TEPCO (circa March 12th)

  24. FSB (History)

    archjr — oatmeal did nothing for my smugness. Will try sea-water and boric acid.

    It does produce gas I’m told. Hold your nose.

  25. Eve (History)

    What is the configuration of the unspent and spent fuel rods in reactors 4 to 6 and 1 to 3? Were they likely to move in a magnitude 9 earthquake? Perhaps my questions are a cognitive hazard.

    • Eve (History)

      Configuration of spent was provided earlier – but the unspent fuel?

    • Anon (History)

      Reactor 4 was “off” I believe

    • Eve (History)

      Sure there was no fuel in the reactor… all the fuel is in the storage pond due to inspection. So 783 fuel rods… when were they loaded, what efficiency were they run at, where they mixed oxide etc?

  26. Anon (History)

    Forwarded msg from Bulletin — Hairs, etc. may wish to contribute:

    Dear colleagues,

    We have been following very closely the events of the past few days at the
    Fukushima plant and in Japan generally. We are devastated by the terrible
    news and wish to contribute to a clear analysis of the evolving tragedy—a
    tragedy for the Japanese people and a tragedy for humanity.

    We are asking experts to send us their observations about the unfolding
    events to post in an “Expert’s Corner” that we’re developing now for our
    website *We would value contributions from Pugwash
    experts*. Please contact us with your technical reports and initial
    assessments so that we can provide the most accurate information to our
    readers around the world.

    [I deleted Kennette’s email. Let me know if you need it.]

    Thank you all very much for your generosity and compassion, as well as your

    Warm regards,


  27. Anon (History)
  28. Andrew Tubbiolo (History)

    Here’s a question from the peanut gallery for the nuclear engineers out there. Why not have a means of flaring H2 as it’s generated in the core? Basic conservation of energy says you’d generate no new net heat that was not already expended, and as we have seen it’s going to be released anyway. Why is it allowed to build up? I remember as a 10 yo listening to coverage of 3 Mile Island and talking heads dreading H2 buildup. So obviously this has been a known issue for some time.

    • John Schilling (History)

      It’s not clear whether you are talking about flaring the H2 while it is still in the core, or as it emerges. Actually burning the H2 in the core, or anywhere else in the containment structure, would require pumping in oxygen – by the time there is any H2 being generated, the core will be quite anoxic. The oxygen would have to be pumped in under pressure, not something I would want to count on after a 9.0 earthquake and associated tsunami have worked over my machinery. And it would add roughly 120 megajoules of energy to the core per kilogram of H2 eliminated – thermodynamically speaking, you end up with zirconium oxide either way, but feeding the Zr free oxygen rather than forcing it to tear apart water makes a big difference.

      Flaring the H2 as it leaves the core, analogous to the natural gas flares at oil refineries, was I believe the plan. That machinery apparently didn’t survive the earthquake and tsunami either. Lesson going forward, and probably reasonable to retrofit to existing facilities, is to add hardness and redundancy to that system.

    • FSB (History)

      folks have done some work on it:

      google “Safety Implementation of Hydrogen Igniters and Recombiners for Nuclear Power Plant Severe Accident Management “