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Fukushima Unit 4 Spent Fuel Pool

Fukushima Unit 4 Spent Fuel Pool Issues and Answers

[A summation of prior posts on the Fukushima Daiichi unit 4 spent fuel issue from the Fukushima Commentary blog. Was the spent fuel transfer a harbinger of apocalypse, or not? As of 12/20/14, the staff at Fukushima Daiichi has safely moved 100% of unit #4’s 1533 stored fuel bundles to the ground-level common storage facility without incident.]

a. The Onset

The spent fuel issue at F. Daiichi erupted with an electrical failure in a switchboard which stopped cooling water flow through four spent fuel pools (SFP) at Fukushima Daiichi. Power was lost at 7pm on March 19, 2013, but all pools were returned to operation by 10am the next day. Tepco announced the problem within two hours of discovery and the Nuclear Regulation Authority confirmed it an hour later. Tepco initially said it was might have been due to faulty switchgear.
The decay heat level being generated in the pools was so low, two years after the Fukushima accident, that it would have taken many weeks before evaporation would have uncovered fuel bundles in all pools. Unit #4 pool contained the largest number of bundles, some of which were producing the highest level of decay heat, and increased in temperature from ~25oC to 30oC over its 15 hour cooling loss. All other pools experienced less temperature increase. The procedurally-desired limit for SFP temperature is 65oC, which was the number the Japanese Press and some politicians were fixated on. Actual fuel tube damage (deformation) cannot happen until temperatures approach 900 degrees Celsius. Hypothetically, the fuel’s Zirconium tubes can “burn” (actually, like a large fireworks sparkler) with temperatures above 900oC. However, before this could happen, all water in an SFP would have to evaporate away. Plus, natural convection would also have to be stopped for a long period of time to reach those high temperatures because the dry bundles would necessarily lose heat to the surrounding environment, and then only with a few isolated locations inside the pool. In other words, the worst-case scenario was so unlikely that it approached the impossible.
Most Press stories focused on the highly-unlikely worst-case scenario, but neglected to put it in any kind of real-world perspective. They implied that the 65oC tech-spec was the point when radioactive contamination will be spewed from the pools. One newspaper went so far as to allege the absolutely impossible. Japan Today posted, “Even used nuclear fuel becomes dangerous if its temperature is allowed to rise uncontrollably to the point where a self-sustaining critical reaction begins, causing a meltdown.” However, temperature alone cannot cause criticality. The fuel must be immersed in water in order to slow down neutrons enough to cause a chain reaction. No water equals no criticality. There would be no meltdown either, because that needs temperature in excess of 2500oC.
Japan Times let everyone know how frightened some of the Fukushima evacuees were. A 27-year-old housewife in the city of Fukushima said, “I am very worried because I have a baby. I want the information to be disclosed as quickly as possible because it will be difficult to evacuate promptly if (an emergency occurs) at night.” Takashi Haga, a 49-year-old office worker, said, “[The power failure] revived the memory of the nuclear accident two years ago. I thought [F. Daiichi] was under control.” NHK World reported that a university student in Fukushima city said the outage caused her serious concern because such problems could seriously affect residents. Thus fear of a spent fuel pool catastrophe compounded fear of radiation in the minds of many evacuees, and the Press exploited it.
Politicians also utilized the issue and some made political hay. In Tokyo, Industry Minister Motegi said the situation was serious and ordered Tepco to fix the problem as quickly as possible. Cabinet Secretary Yoshihide Suga said, "We will make utmost efforts to prepare alternative methods to cool the pools in consideration of a worst-case scenario." (Mainichi Shimbun). Masahide Matsumoto of Katsurao village said, “We will be in trouble unless Tokyo Electric Power Co. properly investigates the cause (of the outage) and restores power.” Such statements from public officials made it seem that without political pressure, the problem would not be corrected. Actually, the people at F. Daiichi were not sitting on their hands, playing Pokemon. They were working diligently to find the cause of the power loss, fix it, and get the pumps re-started.
The issue continued to dominate the Japanese Press for many days. Most Japanese newspapers dutifully reported that power was restored. Some did not. The cause was an electrocuted rat in one of the three temporary power-supply switchboards for the SFPs which (because of interconnections) knocked out all three. (Kyodo News; Sankei Shimbun; Japan Today) The Press articles strongly implied that the event was the result of the temporary switch boards being “makeshift” – literally slapped together in a chaotic scramble – which allowed the culprit rat to get into one of them. The term “makeshift” is misleading and inappropriate.
The switchboards were dubbed “makeshift” by all but one of Japan’s major news outlets, the lone exception being the Yomiuri Shimbun. Makeshift is defined as “a crude and temporary expedient used as a substitute”. (Merriam Webster) However, the Press used the term in the context of related synonyms such as “slapdash, hit-or-miss, primitive and/or amateurish”. Yes, the installed switchboards were temporary until the in-plant panels could be re-powered…which could not happen until the radiation levels were considerably lowered inside the reactor buildings. However, the temporary technology had functioned without a hitch for nearly two years. Such a track record hardly qualifies as slapdash, primitive or amateurish. Two of the boards were fabricated inside a nearby building to keep environmental effects from causing a problem with them. The third was located on a high-tech power-supply truck, the bed of which was enclosed. It was the truck that was violated by the deceased rat.
The opportunity was not missed by the prophets of nuclear energy doom who spouted visions of apocalyptic cataclysm. The most common topic of misinformation was the phantom “teetering” of “fragile” reactor building #4 because the 3/15/11 explosion caused one of the non-load-bearing outer walls to bow out a few inches. There were also wildly-embellished speculations on a radiological release of 100 to 1,500 times worse than Hiroshima/Nagasaki. These prophets caused unnecessary psychological damage on the unsuspecting people of Japan, and served no useful purpose.
As said earlier, the typical worst-case scenario was the notion that decay heat could have built up enough to boil off all the water, dry out the fuel bundles and burst them into flame. To begin, we have real-world, Fukushima-specific evidence to show that the pools would not get hot enough to boil. The power to all SFP cooling systems was lost on 3/11/11. Recovering power to any SFP cooling system at the station was not possible until the temporary power cable from the 1km-distant transmission system was spliced together and energized on 3/17/11. Several days of inefficient water drops from helicopters provided some help with units 1, 3 and 4 SFPs… very little help. For all intents and purposes, SFP cooling was lost for six days! The level of heat generation in all the pools was at their peak. But, none of the pools boiled. The waters in the unit #3 and 4 pools were heated to about 90 OC and evaporated rapidly enough to produce the “white smoke” reported world-wide, but there was no boiling. AREVA and MIT pointed out that it would have taken at least ten days before the tops of the fuel bundles in any of the pools would have become uncovered. It would have taken 5-7 more days for any of the pools to have evaporated to dryness. But by the time of the SFP power loss in 2013, decay heat had dropped constantly for two years. The rate of heat-up was but a small fraction of the original case. It would have taken three or more weeks - not 10 days – to uncover the tops of stored fuel bundles, if-and-only-if no-one did anything to mitigate the problem.
It is highly unlikely, but not impossible that dried out fuel bundles could get hot enough to cause a massive release of radioactivity. Possible does not mean inevitable. Possible means conceivable or hypothetical, but not inescapable. Regardless, dried out fuel bundles would have to heat up beyond 900 oC for sufficient deterioration of the outer Zirconium tubes in the bundles to allow a radiological release. Conceivable? Yes. Probable? No! As the two-year-reduced heat production warmed up the dried bundles, the heat would be naturally lost to the surrounding air. As the bundle temperatures rise, the rate of heat loss necessarily increases with it. At what point would the bundle temperatures have peaked? That’s a matter of assumption, but it would certainly have been considerably less than 900oC. Since 900oC was nigh-impossible, reaching a “meltdown” temperature of 2500oC was out of the question.
Thus, the worst-case SFP accident scenarios of March, 2013, should have been be dismissed by Japan’s Press and antinuclear politicians.

(Pictures of the truck and switchboard -


b. Prophets Profit on Japan’s fears

For several weeks that followed, America’s preeminent prophet of nuclear energy doom toured Japan. Arnie Gundersen preached that Fukushima Daiichi was an accident still-in-progress, with the greatest potential for disaster being the spent fuel pool (SFP) of unit #4.His prolific panderings had precious little real-world evidence to support them, but the Japanese Press and sympathetic politicians treated him as an expert voice to be reckoned with. His book on Fukushima had skyrocketed to the top of the Japanese non-fiction best-seller list the year before, and he surely received consultation fees for his tour of appearances. Technically his company, Fairwinds Energy Education, is not-for-profit. However, one can be sure that he paid himself handsomely out of the windfall of money from Japan. Preaching that Nuclear Judgment Day is an ongoing possibility had become a lucrative endeavor.
During his trip to Japan in late August and early September, Gundersen effectively exploited the on-going fears relative to unit #4 SFP. In a Kyoto public presentation, Gundersen said, "The spent-nuclear-fuel pool at Fukushima No. 1's unit 4 remains a sleeping dragon. The situation and possibility of a fuel pool fire in reactor 4 in the days [immediately] after the [March 2011] quake was the reason the U.S. government recommended that the evacuation zone be [set at] 80 km." (1) The statement itself was grossly misleading. The Nuclear Regulatory Commission’s Chairman Jaczko incorrectly told America’s Congress that #4 SFP was dry on March 16, 2011, and that fuel bundles in the unit #2 SFP were protruding out of the water. Unsure about what was actually happening at the plant, combined with America’s 50 mile emergency planning zone philosophy, Washington naively ordered all Americans within 50 miles (80 kilometers) to get out of Dodge. Did Gundersen mention that the US congress over-reacted and the American evacuation was unnecessary? He did not.
Gundersen added that America’s Brookhaven laboratories did a study on a hypothetical SFP fire in 1997 which would cause the permanent evacuation of a 50 mile radius. (2) However, the study itself says nothing about an evacuation radius… only that near-by evacuations would be prudent if the presumed fire took place at an actual nuke. Further, in 2003 the NRC updated the 1997 study and said that a Zirconium fire was a highly unlikely event and Brookhaven’s assumption of releasing between 10% and 100% of the contained fission products was just plain wrong. The NRC stated that these over-estimations and were off by as much as an order of magnitude (factor of ten). Further, the study assumed no human intervention to mitigate the postulated event (an assumption common to the majority of worst-case nuclear scenarios). Clearly, Gundersen intentionally misrepresented the content of the Brookhaven study, and conveniently neglected to say anything about the NRC’s subsequent revision of the report.
To make matters worse, he stretched the truth even further by saying, "The Fukushima plant's reactor 4 (pool) has 1,500 fuel bundles. That's more cesium than was released into the atmosphere from all of the nuclear bombs ever exploded, (which total) more than 700 over a period of 30 years. That's also why the U.S. recommended an evacuation with an 80 km radius." This was not why America recommended an 80km evacuation radius. It had nothing to do with nuclear weapon associations. But, it seemed believable in Japan where the Hiroshima Syndrome (3) holds sway. Confusion between reactors and bombs is commonplace in the island nation, and Gundersen exploited it to the maximum extent possible.
Finally, Gunderson boasted, "I told Tepco that while I realized they hoped and believed that there will always be water in the nuclear fuel pool, I had to ask whether or not they had (already prepared and stationed) any chemicals to put out a nuclear fuel pool fire in the event they were wrong. Tepco's response was that there was nothing in the fuel pool that could burn, a statement I find appalling." For someone touted as a nuclear engineering expert, his statement was appalling. The heat generated by spent fuel drops dramatically over the course of time. At the immediate point of reactor shutdown decay heat is 7% of full power. An hour later, it’s about 1.5%. At the end of one day, it’s below 1%. After 10 days, it’s about 0.3%. The “hottest” fuel bundle in SFP #4 had been out of the reactor for more than two years and its heat rate was in the 0.01% range! In other words, the fuel bundles’ heat production in mid-to-late 2013 would never get them hot enough to ignite the Zirconium cladding. Gundersen’s statement was patently inexcusable for someone ballyhooed to be an expert of repute!
Now, here’s the truly depressing question… why was Gundersen given such high esteem in Japan? Prior to 3/11/11, there was absolutely no public education in Japan on nuclear power plants, nuclear safety, or the realities of radioactive decay. Nothing! Even teaching about the aftermath of Hiroshima/Nagasaki had been out of the schools for three decades. The only nuclear and/or radiological education to be found was on the university level, and only for those aspiring to be part of what is known as Japan’s “nuclear village”. Japan was, and for the most part still is, a nation plagued by abject nuclear and radiological ignorance. Because of ignorance, a foreign street corner prophet of nuclear energy doom was given free license to line his pockets with Japanese yen.
Another of the prophetic voices was Harvey Wasserman, a long-time American nuclear fear-monger. (4, 5) He unabashedly proclaimed in September, 2013, “We are now within two months of what may be humankind’s most dangerous moment since the Cuban Missile Crisis.” He assured his readers that the unit #4 building was “…tilting, sinking and could easily come down in the next earthquake, if not on its own.” Tokyo Electric Co., owner of F. Daiichi, had brought in two independent experts to judge the structural condition of the unit #4 Primary Containment Vessel, of which the SFP is part. Both specialists said the building was not tilting…not even a tiny bit. In addition, while much of the several-hundred-mile-long Tohoku coast dropped about 2 feet in elevation due to the 3/11/11 earthquake, there is no record of unit #4 at F. Daiichi “sinking” on its own. Wasserman was appealing to popular rumors, and not the facts.
Wasserman also wrote that “Spent fuel rods are the most lethal items our species has ever created.” Worse than a nuclear weapon? Worse than any weapon of mass destruction? Where did he get this preposterous notion? He asserted that his nightmarish vision would release 15,000 times more fallout than the bombing of Hiroshima. Actually, the big-number prediction was entirely based on Cesium-137, which is a trace isotope from nuclear weapon detonations. Wasserman wanted us all to believe his 15,000-bomb estimate is for the entire matrix of bomb fallout, which is (at best) incredibly misleading. Then there’s the problem with getting all the Cesium out of the 1331 spent fuel bundles and into the atmosphere. 90-95% of the Cesium is too-deeply buried in the Uranium fuel pellets to be releasable, even if the apocalyptic, all-fuel-bundle fire scenario were plausible.
Wasserman also cited another long-time American antinuke, Robert Alvarez. Harvey used Alvarez’ estimate that the spent fuel bundles contain 85 times more radioactive Cesium than was released by Chernobyl. While there may be a kernel of truth to the numbers cited by Alvarez, the fallacy is in getting it all released to the atmosphere. Wasserman says that it would happen because when spent fuel tubes are exposed to the air they can ignite and release all of their contents. Wasserman further stated that if the building collapsed, the fuel bundles would all burn and a world-wide cataclysm will ensue. The US Nuclear Regulatory Commission studied this sort of scenario extensively, long before Fukushima happened, and found that after 180 days with Boiling Water Reactor fuel (Fukushima’s reactors are all BWRs), the rate of heat production due to radioactive decay is insufficient to cause Zirconium to burn. (6) Please recall, the “newest” spent fuel bundles in unit #4 SFP had been there since November, 2010, and the rest had been there many years longer. Thus, they could no longer get hot enough to burn.
Wasserman added to the rhetorical circus when he evoked Arnie Gundersen’s fantastic fabrication that the unit #4 fuel bundles were “…damaged and embrittled to the point of crumbling.” The problem with this notion was that there was no proof of Gundersen’s claim, other than his own confabulated speculations based the unfounded rumor that the pool boiled the week of 3/11/11. While there was some debris on the tops of the closely-packed unit #4 bundles, all actual studies showed no damage to any of them. In fact, in July of 2013 Tepco removed two of the bundles and diligently inspected them for damage. They found nothing! (7)
Gundersen also called the impending fuel transfer is unprecedented in human history. This did contain a kernel of truth. 1331 spent fuel bundles had never been moved in one continuous operation before. However, the level of risk with this removal was so close to zero as to be unworthy of mention with any nuke plant other than Fukushima. Gundersen unabashedly embroidered his wild speculation, calling the operation “unique and daunting” – so much so that it must be done with “100% perfection”. Wasserman expanded on Gundersen’s claim by saying that if the attempt failed, the bundles would be exposed to the air and burn with horrific consequences, causing the pool itself to crash to the ground and create a pile of fuel cells that could fission and “possibly explode”. There is no known reason why a fictitious spent fuel fire could magically cause a massive, steel-reinforced concrete structure to collapse. Further, reactor plant spent fuel is many, many times too dilute in fissionable isotopes to detonate…or even fizzle!
Wasserman also cited a nuclear-naïve former Japanese ambassador to further support his apocalyptic claims. Ex-ambassador Mitsuhei Murata said full-scale releases from Fukushima “would destroy the world environment and our civilization. This is not rocket science, nor does it connect to the pugilistic debate over nuclear power plants. This is an issue of human survival.” Since when does a mere politician with no nuclear credentials whatsoever serve as valuable evidence for anything nuclear?
But, Gundersen and Wasserman were not the only prophets to predict potential doom with the unit #4 spent fuel transfer. Helen Caldicott of Australia, another several-decades-long nuclear power basher, said that if the phantasmagoric pool collapse caused all the bundles in unit #4 SFP to spill out into a pile “the cooling water would dissipate, the fuel rods would spontaneously ignite releasing 10 times more cesium than that released at Chernobyl, contaminating much of the Northern Hemisphere and more than 50 million Japanese people would need evacuating.” She called the impending spent fuel transfer a “risky procedure” because the bundles were so “damaged and twisted that they will not be able to remove them from their racks.” (8)
All of the above bombast would probably have been for naught if it were not for the Japanese Press. International antinuclear luminaries were given “expert” billing, and Japan’s news media ate it up with a gusto usually reserved for a gourmet feast. One representative example comes from Japan Times, which posted, “There are 1,300 used fuel rod assemblies in a pool above the reactor. They weigh a total of 400 tons, and contain radiation equivalent to 14,000 times the amount released by the Hiroshima atomic bomb. The spent-fuel pool, standing 18 meters above ground, was damaged by the earthquake and tsunami and is in a deteriorating condition. It remains vulnerable to any further shocks, and is also at risk from ground liquefaction.” (9) The article goes on to say that spent fuel transfer is ordinarily a difficult task (which it isn’t) using computers, but the unit #4 bundle movements must be done manually, “And if something does go wrong, the consequences could be far more severe than any nuclear accident the world has ever seen. If a fuel rod is dropped, breaks or becomes entangled while being removed, possible worst case scenarios include a big explosion, a meltdown in the pool, or a large fire.” The Times added that any of these situations could lead to massive releases of deadly radionuclides into the atmosphere, putting much of Japan, including Tokyo and Yokohama — and even neighboring countries - at serious risk.
Meanwhile, the prophets of nuclear energy doom were stirring the cauldron of fear outside of Japan. A petition by 17 international antinukes was sent to the IAEA asking for monitoring by people independent of Tepco, Tokyo and the IAEA. An American on-line petition was signed by over 12,000 people, which alleged the west coast of the United States to be at risk. They also wanted “a detailed inspection of the (Fukushima No. 1) facility by a team of experts who are independent of the nuclear industry, as well as ongoing monitoring of West Coast and Hawaii water, air and food for radiation.” (10)
I predict that when the transfer of spent fuel from unit #4 SFP is over, and nothing of any consequence happens, one or more of the following will ensue;
1 – The antinuclear prophets will take credit for it, saying that their reproaches made Tepco and Tokyo take safety precautions beyond those initially planned,
2 – The unit #4 spent fuel transfer was merely practice for the much more dangerous, even more unprecedented removal of spent fuel and meltdown residue from units #1 through #3, and/or
3 - The Japanese Press and the prophets of doom will say something like this… ”WHEW!! That was a close one!”

Part b. references:




4. Wasserman, H.; Humankind’s Most Dangerous Moment: Fukushima Fuel Pool at Unit 4; Global Research; September 20, 2013.  

5. Wasserman, H; Demand for a Global take-over at Fukushima has Hit Critical Mass; Common Dreams, October 1, 2013.

6. NUREG CR-4952 -

6. Japan utility takes out 2 Fukushima nuke fuel rods;

8. Caldicott, Helen; The Medical Implications of Fukushima; July 10, 2013.

9. Government must take over Fukushima nuclear cleanup; Japan Times; August 29, 2013.



c.  Cherry-Picking Japanese Press Feeds Spent Fuel Fears

Japan’s leading English-language newspaper, Japan Times, started a news media feeding frenzy as the start of the fuel transfer approached. On November 6, 2013, the Times posted an article which was headlined “Tepco feeling heat over fuel removal”. (1) They selected the most outrageous foreign and domestic voices of criticism for the impending operation, while at the same time conveniently avoiding statements by long-standing antinuclear critics who said this was much ado about nearly nothing.
Let’s look at fear-mongering statements included in the Times article. In a letter to America’s president, former Japanese ambassador to Switzerland, Mitsuhei Murata, said, “It is urgently needed to set up an international task force to assist Japan by deploying all possible means to reduce the risks of the imminent first unloading of spent fuel from unit 4.” Next, Harvey Wasserman was cited, saying that Tepco does not have the scientific, technical or financial resources to do the job on its own. He reiterated that the work “may be humankind’s most dangerous moment since the Cuban missile crisis. We are petitioning the United Nations and Obama to mobilize the global scientific community to take charge of the nuclear power plant and the job of moving these fuel roads to safety.” These are but two of several scary criticisms in the Times piece. There were no “balancing” statements provided.
There were several antinuke sources that might have been used to balance the report.
The Times should have followed the lead of New York-based Bellona newspapers which posted a parallel article with a semblance of balance. (2) Bellona first cited the antinuclear Natural Resource Defense Council’s senior scientist Thomas Cochran, who said, “That Tokyo would have to be evacuated is complete nonsense. There are lots of worries at Fukushima. [The fuel pool] is not one of the pressing ones.” Next, Union of Concerned Scientists’ expert Edwin Lyman said a pool accident is not a risk of significance, and “The vast majority of fission materials are encased in ceramic material – if a fuel assemble casing broke, you would be dealing with noble gasses as well as a small amount of radioactive ones, but I don’t think that would cause any sign of off-site exposure.” These were not voices of the so-called “nuclear village” or international nuclear community. They were about as non-nuclear-community as it gets. However, there was nothing about their position on the matter in the Japan Times.
Was The Times turning heel on the NRDC and UCS? Probably not. There was another journalistic strategy at work. The Times was “cherry-picking” – carefully selecting only the most desirable sources to support a pre-conceived agenda. This is not atypical with much of the Japanese Press. Usually, all nuclear critics line up on the same side of the field, if you will. But, in the case of the spent fuel removal scheduled to start in the middle of November, there was no such uniformity among them. The Times was intentionally ignoring opposing viewpoints, performing a disservice to the public at large, and only interested in keeping their readers on edge.
It should be noted that one English newspaper in Japan went a bit further than the Times by predicting future apocalyptic situations at F. Daiichi associated with fuel removal. Japan Daily Press said the unit #4 spent fuel removal was merely “a good opportunity to practice” for what they feel will be even more risky future spent fuel handling at the nuke station. (3) The JDP added, “The more dangerous affair will be extracting the fuel rods from the three molten down cores, where a small mistake might become the spark that starts a whole new nuclear disaster on its own.” The JDP also said, “Tepco cannot be trusted with this dangerous process by itself”, and called for international assistance.
Regardless, after all the spent fuel from unit #4 has been safely transferred to the nearby common storage facility, it seems the scare-mongering will continue with removing spent fuel and melted corium from units #1 through #3. The beat will unquestionably go on, and Japan’s cherry-picking Press will do their utmost to keep their readers angst-ridden.






d.   Fairewinds’ Gundersen Guarantees Problems

The week of November 18, the staff at F. Daiichi transferred 22 unused fuel bundles from unit #4 spent fuel pool (SFP) and loaded them into a common storage facility 100 meters away. The process went without a hitch. However, America’s provocative antinuclear voice, Arnie Gundersen of Fairewinds Energy Education, said the dangerous part was yet to come. In fact, he assured us there would be accidents during the removal of the irradiated spent fuel bundles which would release so much radiation that workers would have to abandon the effort.
In his massively misleading video of November 15 entitled “Remove TEPCO Before Removing Fuel”, (1) Gundersen said Tepco was incompetent, “outgunned”, and had no commitment to informational transparency. He said, “Tepco has never been committed to getting information to the public in an accurate and timely manner”, the staff at F. Daiichi hasn’t the needed expertise, and they don’t have the money to do the job right. Gundersen called for an immediate stoppage of the fuel transfer process and a replacement of Tepco staff because they were “not engineers”. Further, he demanded “citizen oversight to make sure the job is done correctly.” He went on to say this wouldn’t happen because “The nuclear priesthood will circle the wagons and not tell us everything that is going on [because they are not] concerned about the dose Fukushima Prefecture is getting and the health effects being hidden.”
Gundersen re-asserted that the irradiated bundles in the pool were brittle and the racks holding them had been deformed to the point that they would not be capable of removal without breaking them. He then added the following guarantee, “I assure you there are not many surfaces that are vertical and horizontal anymore.” Gundersen assumed there must be rack deformities due to the large chunks of debris that fell on them from the explosion of March 15, 2011. Plus, “…and we know that after the accident they boiled violently,” which he said warped the plates. Finally, because of small debris pieces he said must have worked their way between the fuel bundles and the rack side-walls, the removal would create so much friction that the bundles would “likely snap”, releasing enough radiation to force the staff to abandon the operation.
Absolute balderdash!
First, for embrittlement to happen Zirconium would need to have the property of neutron absorption. Structural steel can absorb neutrons and become embrittled over many years of bombardment at full power reactor operation, but not Zirconium. Fuel bundles are a grouping of Zirconium tubes filled with uranium fuel pellets. The reason Zirconium is used as the structural metal is because it is essentially transparent to neutrons. Neutrons pass through Zirconium similar to light passing through a window pane, which is why the metal was used in the first place. In fact, Zirconium defined as a “strong, malleable, ductile, lustrous, grayish-white metal…resistant to corrosion…and very poor at absorbing neutrons” (2) Hardly something easily embrittled by neutrons.
There is usually a kernel of truth with what Gundersen says, but he confabulates it into something that bears no resemblance to the truth it came from. Zirconium can be embrittled if immersed in water and heated to around 900oC. If this happens, the metal strips Oxygen atoms from the water molecules by the process known as oxidation, and produces free hydrogen. This is where the hydrogen came from which caused the three explosions at F. Daiichi. However, none of the spent fuel bundles in F. Daiichi’s unit #4 SFP had ever been heated to more than about 300oC. Further, the alleged boiling of the pool never happened. Japanese helicopter pilots who flew over the pool said it was not boiling and it was never empty. For Gundersen to assert to the contrary is nothing more than the intentional perpetuation of convoluted rumors convenient to his argument.
Thus, Gundersen’s claim of the unit #4 fuel bundles being brittle enough to easily “snap” completely collapsed. In addition, his claims of the F. Daiichi staff being incompetent and Tepco not being trustworthy were nothing more than vacuous rhetoric. There’s no-one in Japan more qualified to do the job than the staff at F. Daiichi. Finally, his reference to the fictitious “nuclear priesthood” is merely an appeal to a time-worn main-stay of the antinuclear persuasion since Three Mile Island in 1979. It does not exist, never existed, and never will. If there is a “priesthood” with respect to nuclear energy, it is comprised of the leaders of the antinuclear demographic, the most prominent of which might be Arnie Gundersen.


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