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  1. Jazcko was wrong.

    His information came from those in Japan liaising with Tepco, and Tepco were wrong.

    The reason they were wrong in their estimation tf the condition of SFP 4 was that there were 2 failures that they were not expecting.

    1. Reactor 4 was full of water, when in fact it was meant to be emptied some days before. The failure to follow procedure was not known to the people at Tepco trying to work out the state of the plant.

    2. The pneumatic gate seal from Reactor 4 to SFP 4 failed resulting in the water that was not meant to be there leaking into SFP 4.

    So you are right – it was not boiling as expected by Tepco and therefore by the NRC and therefore as passed onto Jazcko.

    But – you were right by accident, in that a human error and a seal failure made the situation not as expected.

    If you consider theis to be proof that your claims of nuclear safety are correct, or some claim against Jazcko correct you are mistaken.

    BTW I am taking my information from the transcripts of the NRC conference calls and from Tepco’s own press releases about the leak.

    1. @Richard

      You are saying there is a direct pipe connection between the spent fuel pool and reactor 4 that only has one valve between them?

      That sounds dead wrong if I am understanding your claim correctly.

    2. Yep I just checked the photo again of the Mark 1. Took about .20 seconds. The spent fuel pool is above the level of the reactor. Your claim would have the water draining uphill. I must say that radiation which is the most poisonous material ever known to humanity able to kill millions with a single atom, has now been shown to counter act gravity. Now we will have problems with the waste floating away. The NRC must regulate the antigravity aspects as well. They are negligent !

      1. In a refuel outage, both the Drywell Head and Reactor Pressure Vessel Head are removed, with the Reactor Cavity flooded up.
        Flooded up means to the same level as the Spent Fuel Pool.
        The Reactor Cavity Gate has a pneumatic rubber seal that will allow equalization of the Reactor Cavity to the Spent Fuel Pool after air pressure is lost.
        As SFP level drops due to decay heat induced evaporation, the gate seal will allow the Reactor Cavity Water (initially at the same level) to leak towards the lowering Spent Fuel Pool.

        In effect – two slow processes oppose
        1) Evaporation tends to lower SFP Level
        2) RPV Cavity Gate Seal Leakage provides cooler additional inventory to the SFP

        Antigravity remains the domain of sci-fi.

    3. Richard
      Not everything that can go wrong will. Just as, not everything that can go right will, either.

      I doubt nukes even Japanese to have a tremendous disregard for procedures and this observation can be more succinctly stated as a lapse in communications. This is called the fog of war. It is real. There are other ways of estimating the volume of water in the spent fuel pools using radiation readings from helicopters. I was able to do this and get within 1 meter of actual water level using some very crude assumptions with the data that Jazcko had at the time I his profecies.

      The great thing about operating reactors is that very little information is needed to keep them safe or to understand their current state. Jazcko did not have the background to have this level of understanding and I doubt the Japanese had very much training in this type of gross assessment. I do know that the NRC staff has such proficiency and as has been subsequently reviewed were ostricized by Jazcko’s leadership style. Even though he had the resources he was technically incompetent to have the right to be such a prick.

      So did they get lucky with the reserve water? Yes. Did it give then more time? Yes. The important question that you miss here is was the time to initiate corrective action short compared to the time to identify the problem. The answer to this question is. Yes, very much so.

      I am going to get technical here and base my next statement in actual theory. The approximation of a complex system that evolves slowly can always be approximated to first order accuracy using simple linear thumb rules. We use this all the time in reactor analysis.

      The bottom line is that once the reactor is shut down everything that happens takes a long time to happen the longer after the shutdown the longer time to catastrophe.

      Here I fault the other NRC commissioners who had acess to the support staff and access to the knowledge to make these types of assessments and allowed Jazcko to run amuk.

      The information was there as this was all happening. I knew this then and was able to accurately piece together what was happening and make salient recommendations as the casualty transpired. It took 5-days from when I mentioned on NPR and emailed every contact I had in the nuclear industry to get those pump trucks on site. When the trucks got on site, they were able to control the level. We do not need gold playing to operate a nuclear reactor. We need to have a simple first order understanding of what is important and why.

      If you have access to it, I suggest you sit down and spend some time with NRTM-20 and learn exactly what types of indications you have available to you and just how valuable a radiac is in diagnosing the health of a plant. Leslie Corice does this at his blog Hiroshima Syndrome. Rod covers it in the previous post. The three of us all share a common background, we are all Navy Nukes. I was able to determine the water level with it when no one else had a clue.

      1. @ Cal Abel,

        Your comment:

        The bottom line is that once the reactor is shut down everything that happens takes a long time to happen the longer after the shutdown the longer time to catastrophe.

        was corroborated by Richard Black of BBC news 5 days after the event. He stated then:

        As time passes, the reactors should in principle become less dangerous.

        The rate at which they pump out heat decreases quickly, and by now the rate should be down to about one-thousandth of what it was a week ago, just before the Tohoku earthquake triggered a shutdown.

        And a keeper from Richard Black 5 days after the event:

        Greenpeace, with a long history of opposition to nuclear power, is still not convinced that the time has come to declare that the risk of a major accident has subsided.

    4. Richard, the calculation here makes clear that even without the water from the flooded up Reactor Cavity it still wouldn’t have been possible to empty the pool by evaporation that fast.

      It’s not only luck and that seal failure that saved the pool.

      The calculation also makes clear that with a lower level of water you get a lot of gamma radiation above the pool, which makes it very needed to refill it as early as possible.

    5. Did they fix the Pneumatic Gate Seal? Is the level in the Spent Fuel Pool dependent on the Refueling Cavity Level? If so, what is supporting the Reactor Cavity Level? The Refueling Cavity Seal?

  2. Of course there may have been other factors in Tepco getting their state assesment of SFP4 wrong.

    Did we all think SFP 4 was dry when Jazcko said it was – well no.

    Did he make it up? Well as we found out later – No.

    Still can’t see how this answers anything but the reporting of the way out fringe. It certainly doesn’t change the position or view of the situation of the many anti-nuclear people I have spoken to because we go by facts that could be established from the data, and the US Govt public statements were wrong in both underestimating the risk, and overstating the current SFP state. We knew that.

    1. Richard

      Yes the chairman was wrong. So are you. The pools are tubs of water. Unless they were cracked they would keep their water. Since they are made of very very thick steel it is very difficult to crack them. So the research above did not credit a valve left open but simply ran the numbers and concluded there was enough water and it could not boil.

      Rod ran those numbers too and came to the same conclusion. I guess they were running old government x86’s and their spreadsheets took some days to finish the calculations. Rob could afford a MacBook so was far faster.

  3. The nuclear lobby — IF there is a nuclear lobby — ought be slamming this all over the media along with the last report that the steel containment vessel wasn’t breached. But seeing their past “competence” at defending themselves against FUD with fact and record, I’m not holding my breathe!

    To those who say an aggressive nuclear PSA campaign is pointless because it runs counter to energy producers who also own fossil plants as well, then I say why bother with all this? Why don’t Rod and Hiroshima Syndrome and Yurman and Will and others just close shop and forget promoting a self-castrating cause? Maybe the only venue we can really ply our passion is for government-owned nukes!

    James Greenidge
    Queens NY

    1. A PSA campaign wouldn’t be pointless; it’s just unlikely given that the nuclear industry’s official organs are ineffectual due to lack of funding and general ineptness. Expecting any help from that quarter is a waste of time. The only way forward is by creating a grassroots movement, and that may be easier than it looks.

      Here in Quebec, a freshly elected government tried to pay off its support from certain Green elements by making an election night announcement that they would close the
      Gentilly Nuclear Generating Station. They were under the impression that this would be a quick win but were surprised to find that this was not going to be the case. A large number of people showed up for a demonstration in support of the plant and the government was forced to defer the final decision to a parliamentary commission.

      This will not necessarily save the station as the power is not really needed and refurbishment is going to be expensive, but the lesson to draw from this is that support from the bottom can have a profound effect, far greater than most think. This is where the battle for nuclear energy will be won or lost; on the ground, not by any top-down action by industry lobbyists or friendly politicians.

      1. Yes, that is spot on. It is easy to dismiss industry statements or PR as self interested. Which is not to say that the industry should be silent. It certainly should not be.

        In the UK, I think that the likes of George Monbiot, David Mackay etc have probably done more to keep nuclear on the agenda than any PR by Areva or Westinghouse could possibly have done. Their perceived independence is very valuable. Moving that forward at the popular level is of key importance.

        1. @quokka

          Few other industries seem to be afflicted with the notion that their factual statements should be easy to dismiss. Of course, they recognize that there are always some people who will try to dismiss them, so typical industry marketing and public relations arms use an age old technique called repetition to ensure that the dismissals do not happen “easily”.

          Any large business is going to have detractors and competitors that noisily try to beat them down. The normal, effective response to those detractors is continuously investing time and money to tell the positive side of the story, build alliances with others that share the benefits of the enterprise, and to make friends in the advertiser supported media (and campaign contribution dependent politicians) who will defend you against the detractors.

          There is no real “nuclear industry” that sees itself as needing to make those kinds of investments to protect its own self interests and to grow its core business. A large chunk of what some call the nuclear industry is actually just as happy building wind turbines, manufacturing and servicing gas turbines, and building drilling equipment for deep hydrocarbon extraction. Another chunk of “the nuclear industry” consists of electric companies who really do not care which fuels they use as long as the machines are cheap, there are few regulations that slow them down, and the cost of fuel can be passed on as an unpredictable expense that affects all competitors equally.

          My reason for working as hard as I do to share what I know about nuclear energy is that I am convinced that it is the best source of power we have available. It is the source of power that will enable humans to prosper far into the future on a planet with ample resources for all and with clean air and water that is not polluted by constant dumping of massive quantities of combustion waste products. Unlike industries, I am not motivated by money, but by truth and by a desire to leave the earth in a better condition than it was when I was born.

          1. You have a point about electric companies. They dislike being hated for using nuclear power, and it’s not actually a problem at all for them to forward the higher price of renewable to customers, in fact even if not actually making much more profits, more money going through them is still more power at the end of the day.
            For the German utilities, the perspective of losing a lot of money because suddenly the regulators decides to force them to close perfectly well working plants is an extremely negative side of nuclear.
            EDF in France is currently building/buying more and more solar and wind power because every watt they generate out of it is a lot of profit through the feed-in tariffs, and if ever it would endanger the stability of the grid, owning it means they can just stop it.

          2. @jmdesp

            For German utilities, the cash flows generated by nuclear were to allow them to finance England’s nuclear renaissance.

            Now German utilities are busy passing on to their citizens a 47% electricity price increase for next year. Gotta love it when the greens shoot themselves in the foot. Electricity will cease to be a commodity and become a luxury item.

            Merkel is 2 months away from embracing nuclear again. Gotta love those physics PHDs.

          3. @Daniel,

            The German 47% increase is to the renewables levy, not electricity price. That will take the levy to over 5 euro cents/kWh that consumers pay. Of course, this is not a trivial amount.

  4. I know (and worked with) several of these fellows, and all are very smart, capable individuals. From my understanding, much of their actual analysis work was done in the months immediately following Fukushima – several (like my former colleague Ian) were involved with safety analysis to support the NRC for several months following the Fukushima incident.

    In any case, it’s nice to see them getting their analysis out there.

    1. @ Steve

      My apologies to your friends. I am sure they are actually very smart and capable. My sarcasm above was not aimed at them.

  5. Although the temperature would never get to boiling, the key is the amount of inventory available in the spent fuel pool to maintain the temperature at equilibrium. 86 tons of evaporation per day is about 22,000 gallons loss per day. The real points to consider is how high the temperature got based on available decay heat, how much inventory was available once forced cooling was lost, and when did makeup start to replace the evaporation.

    1. @John – the point of my post is that the math is simple. If a steady state temperature is reached when the evaporation rate hits 87 tons per day, calculating the time required before fuel the used fuel is uncovered is a straightforward division problem – volume of water above fuel/volume per day = days until the fuel is uncovered. There is no need for fancy models; a PhD should be able to do the math in his head to realize that there were still many days left before any danger.

      1. A high-school physics student should be able to do it in 60 seconds with a calculator.

        tons/day / (sq. meters of fuel pool) = meters drop per day

        meters water cover / meters drop per day = days left until fuel uncovered.

        In other words, Jazcko does not have the mental acumen of someone able to pass a high-school physics course.

  6. Unfortunately, an old saying applies here: a lie makes it half way around the world before the truth leaves the porch.

  7. Rob, your comments seem right on, except for the bit at the end remarking about the “This manuscript has been authored by UT-Battelle LLC under contract DE-AC05-00OR22725 with the U.S. Department of Energy.” statement.

    You’re reading way too much into that…

    This is just boiler-plate national-lab speak that anyone at any of the labs must put on anything that gets published. It’s highly, highly unlikely that anyone above a division level (a group of about 200 scientists) would have had to approve a technical paper like this. And, that approval only requires checking for sensitive information on security or IP grounds.

  8. I don’t know if these are the exact dimensions of spf4 but its probably good enough to make an estimate.

    Dimensions are 35ft w x 40ft l x 39ft h. There is 26ft of water above the top of the fuel rods. I assume the water is leaving at 87tons/day. Assume density of water at 212F is 8lb/gal. Doing the math results in a loss of ~2.08ft/day or ~13 days till the water level reaches the top of the fuel rods.

    1. I used my method above and got 0.67 meters of loss (about 2 feet) per day, agreeing completely with your estimate.

      87 tons per day is roughly 1 liter per second, or about 15 gallons a minute.  This is not a terribly large amount of water to make up; the single pumper truck with the nozzle on the arm spraying water over the fuel pool was more than enough to refill it unless it had some pretty good leaks.

  9. I had not known that Chairman Jaczko had been misinformed as to the fill sequence of the SPF, so that he did not know the correct status of the water level at the time of the accident. Still, in his defense, there was also no assurance of continued integrity of the SPF when he made his statement.
    The earthquake had been much larger than expected, plus there had been some really powerful explosions of undetermined origin in the reactor building. So the large safety factor provided by the pool’s nominal water content could not be relied upon. Moreover, the Reagan had been forced to abandon its mission because of excessive airborne radiation. So he had solid reasons for his expressed concern.

  10. BTW I just saw this report by Tepco about why a leak of the pool was very unlikely which complements the info here :
    – “SFP is made of reinforced concrete which has a thickness of approximately 140 – 185cm, lined with 6mm-thick stainless steel plate.”
    – “supported by a steel and concrete structure, mostly isolated from the 4th and 5th floor walls”
    – “There are no pipes or drainage holes that pass through the concrete structure of the pool, either on the side or at the bottom of the pool”
    – “pool depth is approximately 11m, about 7m above the top of the 4m-long spent fuels”

  11. Re in NYTimes regarding Italian scientists jailed for not predicting earthquake:: “In Washington, the American Geophysical Union described the verdict and prison sentences as “troubling,” and expressed concern that they could “ultimately be harmful to international efforts to understand natural disasters and mitigate associated risk.”

    How bizarre! They sack these poor guys for NOT trying to out-guess mother nature and panicking regions with Chicken Little alarms, yet anti-nukers cry fire in the theater as a matter of course with off-the-wall mega-death scare tales and fabricated “proof” and other FUD that nuclear reactor accidents are always “imminent” to willfully terrorize a science-clueless public to vote against their own best interest for clean safe reliable power, and not only aren’t they chastised for their irresponsible antics but even praised for it in the media!

    James Greenidge
    Queens NY

    1. It’s not bizarre if you understand the political background, which is not open & honest, to say the least.
      The Green Movement are spending huge amounts to fight the fossil & nuclear fuel industries. They are being well funded.
      The largest political movement on the planet at the moment is UN Agenda 21.
      It is being pushed through by bureaucrats, not politicians.
      Alabama has just banned it, & other states, counties & cities are following suit.
      They see it rightly as an attack on personal property.
      It’s the reason that ~50% of US land is no longer in private hands.
      The New American 10 July 2012 is a must read, if you care for the future of your children, countries & planet.
      Want to know why cod science rules & the Global Warming Scam has such legs?
      It is being well funded, & UN Agenda 21 is the reason. is a clue to what’s going on. is another clue.
      On a much lighter & more hopeful note,, is well worth a read.
      We live in interesting times.

  12. All these calculations were done in Tokyo (TEPCO, NRC, et al) during the crisis. The critical comments posted here are missing some key pieces of information that went into some of the conclusions.

    (1) The explosion of Reactor Building 4 is perplexing. Since the reactor was defueled and preps being made for refueling, the energy source for the explosion was (and is) rather inexplicable. Questions were abound: acetylene bottles? hydrogen bottles? gasoline? hydrogen from RB #3? All of these sources were evaluated and discarded which left zirc water reactions from SPF #4.
    (2) The sudden loss of water could not be explained by evaporation/steaming. Draining via a seal leakage to the reactor vessel was considered, but TEPCO insisted the water level was full over the vessel. So, there was an assumption that the earthquake could have caused a massive leak in the SFP which could also have been exacerbated by the explosion of RB #3 the day before.
    (3) There was a substantial radiation level spike seen 150 miles downwind in Tokyo on or about the 15th. Many months later, the radiation sources are known to be fission products from one of the 3 operating cores (likely from #1). But this was not understood in the early days.

    The Gov’t in Japan were being advised by the US NRC team. Emergency response actions taken did consider strongly SFP #4. It made sense since it was a worse-case issue regarding the types and levels of fission products being released to the environment. Turns out that assessment was wrong. But what if that estimate was correct and the Japanese did nothing to mitigate the possibility?

    1. @Reid Tanaka

      It is never correct to take risky, life threatening actions based on “worst case” fantasies instead of taking prudent actions based on real measurements, realistic analysis, and a fundamental knowledge of materials and physical laws.

      Dr. Jaczko sent a team to “help” but hand picked that team from among the small group of NRC regulators who shared his politically motivated belief that the only safe nuclear plant is one that has been shut down, cooled down, depressurized and defueled.

      As I described in my post on the day that Jaczko testified to Congress that SPF for Fukushima Daiichi unit 4 was dry and posed a grave risk, there were many more important things to worry about. None of those more important things were made any easier to address by adding unreasonable panic to the mix.

      To this day, there remains no evidence supporting the “worst case” assumption that an earthquake could cause a steel tank made of carefully welded plates with no underwater penetrations to leak. Other than some sloshing of water during the shaking, the only source of water loss to worry about is evaporation, which takes place at a rather predictable rate – for the geometry of this specific tank, with its known heat load that rate is about 70 cm per day – roughly 87 tons of H2O. There will be high radiation above and near the tank due to the loss of shielding, but as long as you replace that water in time to keep the rods at least partially covered, there is no danger to the public.

      1. Rod,

        I was embedded with the NRC team as PACOM’s inside guy in Tokyo for the crisis for almost a year. I have to completely disagree with your characterization of the hand-picked NRC team. The lead guy has been in the industry for over 35 years and is a very strong proponent of the nuclear industry. The rest of the team consisted of rotating folks who were like military IAs. They came from all over the country to pitch-in for a few weeks at a time and brought varying levels of experience and expertise. They were all certainly professional and knew their business. No matter what errors were made, they all gave their best technical advice.

        (Furthermore, my guess is that most in the NRC lean in the conservative political direction and are/were no fan of Dr. Jaczko. Feelings about the Chairman or other Commissioners has no impact on professional/expert analysis).

        There were a lot of other agencies involved in the conference calls, so whereas NRC had lead, there was a consensus among the US experts. The best estimate for those experts for RB#4 blowing up was SFP#4. It took months before we had access and could make a determination that there was still water and that the fuel was intact. As far as the 50 mile evac arc, I believe that decision was made by the US experts in DC and not in Tokyo. The Gov’t of Japan did not execute a 50 mile evacuation. I think the criticism of the size of that zone is justified. I don’t believe the criticism of the early day estimate of SPF#4 being at risk is justified.

        We still don’t have a good explanation for RB #4 roof blowing off. And interestingly, high rad levels and massive amount of rubble on a building that had a defueled reactor precluded access to make a better determination.

        Again, the evaporation calculations were done, but leakage from the bottom couldn’t be ruled out. Although you have great confidence that the structure could survive a massive earthquake without cracking the spent fuel pool, and your confidence is bore out by the empirical result of the survival of 10 Fukushima buildings, I’m still a little not ready to say we should have assumed so in March 2011.

        I appreciate your dialog and continuing insights.

        – reid

        1. @Reid Tanaka

          I appreciate your input and your experience and value the fact that you are willing to engage in discussion. I am perhaps being too dismissive and a bit over the top in my characterization of the hand-picked NRC representatives that were allowed to contribute to the response. Please believe me when I tell you that I did not make up my accusation, though I might have embellished it a bit. There is a difference between inviting people with 35 years worth of conservative regulatory experience and purposely not inviting people who have actually been in operational situations requiring damage control responses.

          For me, this is not an issue of conservative versus liberal; some of the readers here can testify that I frequently claim to be a bleeding heart liberal who happens to have a hard head and likes math and science.

          In all of those conference calls that you participated in, did anyone think to ask what the measured temperature of the spent fuel pool was? (Please do not tell me that there was no functional temperature measuring device. I know a little about a lot, including remote sensing.)

          Did anyone think to ask if there was any indication of any particulates with isotopes other than Cs-134, Cs-137, or I-131? Both of those measured indications could have disproved the assumption that SPF#4 was producing large quantities of H2 through some kind of high temperature interaction with zirconium. Heck, did anyone think to read Atomic Insights to find out what the experts who participate in discussions here were writing?

          “Consensus” among “experts” is one of the issues that I rail against here. Another word for consensus on a conference call is “groupthink” where no one challenges the leader or feels empowered to ask hard questions.

          I can testify that it is not always a comfortable situation – I have been yelled at by a three star in front of other three stars for telling him the truth about his legal obligation to fund a particular program that he did not like. I later received several apologies; all I can say is that it was a good thing that I was an O-5 with tenure who knew that he had no hope of any promotions and could speak freely. It was not the only time that I helped to avoid a rather serious mistake by speaking up, but I also know how many times there was no one like me in the room when a bad decision was unchallenged.

          1. Rod,

            Thank you for your comments. I apologize for the delay in response. A little more clarification: the lead guy had years of experience as a plant operator before he moved to the NRC. This included operations at a similar plant. Like most of the rotating team members, he was not from DC. The NRC reached out to all their regional offices for folks with strong technical tickets. I recall that a couple of the members were dis-invited from returning since they couldn’t adjust out from their regulatory mode and adapt into an advisory role.

            Regarding data on SFP #4. We did not have any indications or data, nor was any available; certainly none available after the building explosion. Even weeks later when logs and recorded data became available, I didn’t see any for SFP#4. It is my guess that SFP indications are not one of those critical indications that are supported by the batteries in a station blackout and that the operators were diverted from plant #4 to support the reactor accidents at plants one, two and three. So other than the fire, smoke and steam we could see from cameras and satellite photos through the rubble of RB#4, we could only surmise the condition of the SFP.

            I think it was about 3 weeks later that there was more than a fire hose delivering water via spray (a concrete pump truck started water delivery). The initial photos from the camera at the top of the concrete pump boom were inconclusive regarding the presence of water in the SFP due to poor lighting and trying to peer through the rubble/steam/smoke. I think it was about 6 weeks into the casualty, TEPCO was able to drop a bucket and temp probe dangling from a cable mounted on the concrete pump boom down into the rubble and into the SFP. We finally were able to get a sample which gave us 3 important indications: (1) actual water was in the pool (noted by temperature change); (2) Temperature (which I think was around 80-90C); (3) radiochemistry and chemistry. Note that this was after a few weeks of spraying water into the top of the building with the hope of keeping the pool filled.

            The radiochemistry results confirmed lots of fission products and almost no fuel actinides. We were able to feel confident that the fuel was intact, but it really left us wondering why the building blew up and where the plume of high radioactivity came from. The radioactive plume was later determined to also be fission products likely from plant #1 (or #3).

            The conference calls were not just the NRC. They included many organizations (including NR).

            All said and done, there was a lot of smart guys trying to best surmise what happened in the heat of the battle. Working with them taught me a lot about civilian nuclear power and a great respect for the professionals therein.

            – reid

        2. I really appreciate all these comments. In our paper, we conclude that there should be no big leakage in the pool based on good agreement between the calculated level and measured data during 4/27-5/20 2011. If there was leakage, we wouldn’t have the agreement only based on the mass balance between the evaporation and spray.

  13. thats very interesting. so were the videos recorded live of exposed fuel racks in the sfp at unit 4. guess the plutonium offsite came from a giant farting nearby huh. im really curious to know how you feel about these comments now in 2013 when there is still very serious crisis at fukushima. its very hard in fact for me not to just call you a liar, Rod. somebody is paying you well, you are not working for the ”truth”. cheers.

    1. The plutonium was there long before Fukushima Dai-ichi was attacked by a tsunami. The tiny amounts measured were similar to those in many other places around Japan; as you may or may not remember, there was a plutonium weapon exploded there in 1945. In addition. There were hundreds of atmospheric tests conducted over the Pacific Ocean.

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