Today the Japanese government announced that because of “malicious rumors” and “false reports”, they were to begin censoring the news from Fukushima. This is tragic in that the free and open supply of information has made it possible for analysts such as myself to discern what is really going on there.
Unfortunately a rotten apple or two spoils the basket. I ran across one such rotten apple today in this article in the persons of Arjun Makhijani, Phd, president of the Institute for Energy and Environmental Research, an anti-nuclear organization and author of such deep tomes as Carbon-Free and Nuclear-Free: A Roadmap for U.S. Energy Policy and Nuclear Wastelands, and F. Dalnoki-Veress, a Research Scientist at the James Martin Center for Non-Proliferation Studies of the Monterey Institute of International Studies. Wonder what their agendas are?
One of the persistent false rumors being bandied about is that Unit (you pick the number) has remained or gone critical in the aftermath of the incident after the quake. This is consider to be an impossibility by most credible engineers and physicists but the rumors persist.
The rumor is that the core in Reactor X (in this case Unit 1) has melted and reconfigured itself such that it can resume its nuclear reaction. Given the tiny amount of excess reactivity designed into power reactors and the critical fuel geometry that must be maintained, the is fanciful.
In the article I referenced, the authors go through a long and convoluted calculation to show that an erroneous (later corrected) isotopic analysis of the Unit 1′s cooling water proves that the fuel is critical and reacting. Let’s take a look at the situation.
TEPCO published an isotopic analysis on March 25th that showed an extremely high level (43 milliCuries/cc) of Cl-38 in the water sample. Cl-38 is made when natural Cl-37 absorbs a neutron, kicks out a gamma ray and turns into radioactive Cl-38. The natural chlorine is that in the saltwater they used to cool the reactor in the beginning of the event.
The only problem with this analysis is that Cl-38 has a half-life of only 38 minutes. Considering that it took probably 30 minutes to draw the sample, perhaps 45 minutes to transfer to the Unit 6 radio-chemlab where it sat for an unknown time before being analyzed, one would have to assume that the actual amount of Cl-38 in the reactor cooling water would be many times the 43 mCi/cc reported.
The problem is that the reactor had been shut down for 14 days before the sample was taken. Chlorine is scrupulously avoided in a nuclear plant because it causes intergranular stress corrosion to stainless steel. So the chlorine had to come from the seawater that was introduced quite some time after the reactor was shut down. No nuclear reaction, no neutrons. (neglecting spontaneous fission.) No neutrons, no transmutation of Cl-37 to Cl-38.
Occam’s Razor says that the simplest explanation that fits all the facts is usually the correct one. In this case, the correct explanation is the one that TEPCO provided – a simple mistake in the analysis. They re-ran the sample and the level of Cl-38 came up as “below detectable limits” as one would expect.
Instead of accepting TEPCO’s explanation, our friendly anti-nuke PhDs build a grand conspiracy theory. They go through a long and complicated calculation (which I have no argument with per se) to prove that the only way that much Cl-38 could be present in the water is if the fuel is still critical. Further they slip in the China Syndrome theory that the fuel had to have melted through the reactor vessel and was laying on the floor of the reactor building. We’ll delve into why that’s so silly in a moment.
Lies of Omission
Let’s look at some reasons why this analysis is, in my opinion, a deliberate exercise in deception. Their analysis assumes that some portion of the fuel is laying on the floor beneath the reactor and is undergoing a nuclear reaction. Let’s see why that can’t be true.
The big number one reason is that the reactor pressure vessel is intact and is holding pressure according to the IAEA. There can’t be a huge gaping hole in the bottom of the vessel and the thing still hold pressure. (maybe the IAEA is part of the conspiracy!)
In his drawing of the reactor system labeled Figure 2, he omits one tiny little detail that is critical to his assumptions. The control rod drives. These drives extend about 15 feet below the reactor vessel and enter the vessel from the bottom. If the fuel could have melted the vessel, it would not have had a nice smooth surface to work against and it would not have a clear path to puddle into the slab that he assumes in his calculation. The molten fuel and steel would have had to tumble down through the dense array of control rod drives, causing it to spread out and spatter.
When the reactor SCRAMed during the quake, the control rods were driven into the core by the control rod drives. That meant that as the core disintegrated during the LOCA, the control rods melted along with the fuel. The neutron absorbing material would be mixed in with or at least in intimate contact with the molten fuel, wherever it ended up. This is more than enough to keep the fuel from going critical again.
Low enriched fuel depends on the moderator (water) to be mixed intimately with the fuel in order to achieve a critical mass. In a melted blob, this is impossible.
In his calculations below Figure 3, he assumes the fuel to be at or above its melting point >3000 deg C. Yet to have moderation and to have chlorine atoms in the near vicinity, there has to be water in contact with the mass. What’s wrong with this picture?
Wrapped into this conspiracy theory is his claim that TEPCO measured mysterious “neutron beams” on March 13 (two days after the tsunami) 1.5 kilometers from the plant. This beam supposedly registered 3 microREM/hr on the instrument. It is impossible for a neutron flux to travel that far from the plant since the biological shield was still intact. Just the attenuation from that much air would render it an impossibility.
If one thinks about it for a moment, the more obvious answer is apparent. 2 days after the shake and flood. Instruments first shaken up and then wetted or at least humidified by the tsunami. Spurious indication on the meter or perhaps a mis-reading by an excited tech is the more likely explanation.
In any event, this neutron beam doesn’t fit with the rest of the story but he mentions it just to add more suspense.
Well, you get the picture. A classic case of GIGO (garbage in, garbage out) calculation.
It is unfortunate that in some circles, a PhD after one’s name infers great general knowledge and wisdom. Unfortunately this magazine apparently fell for that common mis-conception. They published a story which, taken in its best light is just plan wrong. Taken in a more realistic light, well….. Consider the agenda.
—Posted by neonjohn on April 24th, 2011 under Energy, Nuclear