- The misconception of a hydrogen explosion inside the unit #2 containment structure on March 15 refuses to go away. TEPCO has once again gone to the Press to try and stanch the misinformational flow by using some previously unreleased information. TEPCO now says the explosion of the unit #4 refueling deck was heard in the unit#2 control room and at the Emergency Response Center (TSC) and incorrectly believed to have been from the unit #2 refueling deck. This error in judgment was because units #1 and #3 had experienced explosions due to hydrogen from their damaged fuel cells, so the belief the same had occurred at unit #2 was logical. In addition, with no fuel in the unit #4 RPV, it was believed a refueling deck explosion with unit #4 was not possible. The disbelieving Press countered with questions about a severe radiological release which occurred in parallel with the “impulsive sound” and rapid pressure drop inside the unit #2 containment on March 15, indicating a hydrogen explosion in the unit #2. TEPCO says they have not been able to determine the reason for the coincident spike in radiological releases. TEPCO added they still believe the airborne surge came from unit #2, but they have no idea how it was released. (JAIF, NHK World)
If unit #2 experienced a meltdown similar to units 1&3 with all things being equal, the refueling deck ought to have suffered the same fate as with the first two. What prevented it? Two possibilities emerge…
1) The “blow out panel” on the unit #2 refueling deck was discovered to be open several days after March 15. Although there is no record as to how or when it happened, it is possible the panel was opened early enough to provide a pathway for hydrogen-impregnated gasses to get out of the building before reaching an explosive concentration. And/or,
2) Unit #2 may have had a much less severe fuel damaging experience than with units 1 and 3. While most reports to date say unit #2 had a full, core-relocating meltdown the same as units 1 and 3, control room records indicate its core was uncovered and without cooling water injection for no more than 3 hours. Control room records show the duration core uncovery and lack of cooling with units 1&3 was at least 2-3 times longer than unit #2. Due to unit #2 having the lowest rate of decay heat production of the three reactors, three hours of core uncovery and non-cooling seems too short for a core-relocating meltdown. If unit #2 had less fuel damage, it only follows that it would have produced less hydrogen…perhaps too little to generate an explosive concentration on the refueling deck.
- TEPCO has announced several rather startling things about the early days of the Fukushima accident, some of which relate to the above. Their new hypotheses are based on temperatures, amounts of cooling water and other data taken from instrument readings. First, they now believe the fuel cell in unit #1 had a full
meltdown, and complete core relocation to the bottom of the RPV. They also believe a considerable fraction of the molten material made its way through the bottom head and dropped to the concrete containment floor below. In addition, the corium ate its way more than 2 feet into the containment floor before solidifying. With unit #2, they now say no more than 57% of its fuel cell actually melted, and some of the corium relocated to the bottom head. Unit #3 is now believed to have suffered a 63% core melt with more relocation than unit #2. (NHK World, Asahi Shimbun, Mainichi Shimbun) We have been saying for months that the least severe core damage was with unit #2. This is the first “official” announcement confirming our position. However, we feel core damage in unit #2 may have actually been much, much less than even this new announcement purports. We also question the relatively low estimate on unit #3 core damage. Unit #3s’s fuel cell produced enough hydrogen to decimate not one, but two refueling decks. Further, the #3 hydrogen explosion was greater than either of the other two. That’s a damn lot of hydrogen! Wouldn’t this indicate unit #3 may have had the worst fuel damage?
- Analysis of the gas inside unit #2 primary containment vessel has been completed. TEPCO states the test results show Xenon to be non-detectable. They add that any Xenon which may exist below the detectability of their equipment must surely have come from spontaneous fission. (TEPCO Press Release)
- Because of a sudden alarm from the airborne “continuous dust monitor” near the Fukushima Daiichi’s Main Anti-Earthquake Building (Emergency Response Center, or TSC), all personnel were told to put on full face masks as a precaution. The requirement for full face masks was relaxed around the TSC several weeks ago (as reported here). Investigation into the cause of the alarm found to be a clogged filter. The filter was replaced and the monitor re-calibrated. The reading shows a 7.9×10-6 bq/cc radioisotope level in the air, which is well below the level requiring full face masks. (1×10-4 bq/cc). Full face masks are no longer needed. (TEPCO Press Release)
- The governor of Fukushima Prefecture, Yuhei Sato, has agreed to the prefectural assembly’s expressed desire to have all nukes within their borders decommissioned. TEPCO points out that such a move, including six completely undamaged units, will have severe economic effects on the prefecture and negatively impact the nation’s energy infrastructure for more than a decade. (NHK World) We will add that the move is one of pure political panic, and leaves all rationality at the doorstep. Yes, it will keep all incumbents in office, but short-term political gain will never compensate for the damage that will occur in the long term. It’s like throwing away six good, safe apples because another four have gone bad, at a time when everyone is hungry.
- NISA has decided to establish what the relative age of the damaged Fukushima Daiichi units had to do with the accident, if anything at all. The agency said there was no evidence that showed the age of the three units had anything to do with the accident. But a few contributing experts said it is too early to make such a judgment when the cause of the accident is still under investigation. (NHK World) The accident was due to the tsunami causing a total, long-term blackout. Period! End of discussion! How much money is going to be wasted in order to prove the obvious? Why not spend the money on tsunami recovery, which really needs it?
- On the other hand, the investigative panel created to establish the cause of the Fukushima accident several weeks ago (re: above), has had its first two members appointed. In other words, it doesn’t really exist yet. Regardless, neither man has any nuclear background or experience, but both have extensive science and technology backgrounds. Kiyoshi Kurokawa, former president of the Science Council of Japan, will be head of the panel and Nobel chemistry laureate Koichi Tanaka will be a panel member. The decision for the appointees to not have nuclear experience was a political compromise in the Diet. (Japan Times) Impressive-sounding credentials do not mean that either of them knows the difference between a neutron and a ping-pong ball. We’re sure they are experts in their academic and experiential specialties, but the subject matter of nuclear science and technology has been largely alien to all other scientific disciplines since World War II. For example…renowned cosmologist and theoretical physicist Micheo Kaku’s superstitious fairy-tales concerning meltdowns, as well as his misconceptions concerning fundamental nuclear processes. In addition, are these two newly-appointed men subject to radiophobia? We also think a critical criteria in the selection process should be whether or not a person suffers the Hiroshima Syndrome.