In the Fukushima ROV #54 diary [May 2] the subject of actual conditions in the reactors came up, as it usually does. The diary offered a TEPCO photo ostensibly showing the calm and orderly condition of the unit-4 spent fuel pool, where absolutely no sign of the displaced assemblies and ragged aftermath of the nearly 3-day zirconium fire that burned in the first days after the tsunami could be detected. Making that photo highly suspicious to someone like me who has been paying attention.
In the comments it was noted per an April 18th [?] story from The Asia-Pacific Journal that the Japanese government instituted an information censorship regime early on to scrub the internet of information that conflicts with 'official' stories about how swimmingly everything at Fukushima is going. All the way to the Japanese government banning foreign and internet-based media from its daily press briefings. If you read that Asia-Pacific article, it is not the least bit difficult to form a rather strong opinion about the amount of information control going on in Japan, not for the benefit of proper protection of the Japanese people impacted by this mass meltdown. Basically, no one can feel confident that ANY of the information coming from TEPCO, the Japanese government or the Japanese press is timely, relevant or truthful.
Given this lockout on truth about what is actually happening at Fukushima, one can easily appreciate the courage of those who do have access to some of the truth about conditions who have spoken out and/or resigned in protest. Most high-profile of these include professor Toshiso Kosako who resigned in tearful protest of the government raising dose levels for schoolchildren in Fukushima province to 2 Rem per year, and Michio Ishikawa, former head of the Japan Nuclear Technology Institute (and notable pro-nuclear apologist), who claimed the reactor cores are completely melted by all indications. Despite what TEPCO and the government keep saying.
There were some rumblings in that ROV about applying censorship on DKos against diarists and/or commenters who might link and publicize these notable dissents from the official government line on the conditions and dangers at Fukushima and what that means for the people this same government has left behind to absorb whatever nasty isotopes the meltdowns send their way now and as far into the future as anybody cares to look. Along the same lines as the live-in DKos nuclear apologists who whine incessantly about anyone who doesn't think nukes are God's Gift to the warming world, or dares to say that things at Fukushima aren't perfectly benign and well under control.
I, of course, am of the opinion that all information is relevant, and since I haven't seen anybody in this country actually "panic" about the situation at Fukushima (outside their own closets, where they can panic all they want), I want to know what all sorts of 'experts' involved and uninvolved have to say. In fact, I am so notably distrustful of all things nuclear that I wrote a diary after the horrendous tornado disasters in Alabama last week specifically about the "station blackout" declared at the Browns Ferry nuclear reservation (3 ancient GE BWRs of the Fukushima design) as a result of downed power lines from those storms.
I'm sure those who are interested enough to have read this far into this diary will be pleased to know that the NRC monitoring mode instituted after declaration of 'unique event' at Browns Ferry has been discontinued. Offsite power to the reactors has been restored, though they remain in shutdown mode until transmission lines going out to customers are fully restored and restart can happen. Interestingly, this announcement mentions nothing about the amount of fuel damage any of the 3 reactors suffered from the loss of power, as original reports had one emergency diesel generator out of service so one of the reactors was on battery backup (for a total of 6 days, though it was an 8-hour battery). We heard nothing more about that after that first day, of course, other than one following report that had reactors 2 and 3 in cold shutdown, reactor 1 still hot.
At any rate, it's good that offsite power from two locations has been restored, and I expect units 2 and 3 to be ready to fire up when the time comes for them to start supplying the grid again. Unit 1 is another issue, I expect at least part of its core to need replacing before it's ready to go back online due to compromised cladding and possibly failed (crumbled) fuel in some of the assemblies. I have attempted to make the point several times during the past nearly two months since Fukushima first pushed its way into our consciousness that it takes mere seconds of time for compromised and overheated fuel in a reactor to transition from merely crumbled to molten. And that once molten, it tends to want to stay that way. It's difficult even for people who have good engineering type backgrounds to understand the dynamics of nuclear fuels and alloys. It's not just overheated metal, to be managed thermodynamically with a short amount of time in a cool-down bath. This metal comes with its own internal heat source, and that's much more difficult to control from the outside.
Our press has, with the help of TVA and government officials, stopped mentioning the condition of Browns Ferry unit 1. I'm pretty sure they had means of backup power (even if shunted from one of the other units' EDGs or a whole bunch of trucked-in batteries) to keep it from melting. They'll likely 'refuel' it and have it online by heavy heat season next winter. It's NOT Fukushima, we dodged the bullet yet again at this elderly nuclear reservation. But while I was looking for updates on the situation, I did run across something interesting from the Sustainable Energy Today blog from March 15 listing various DOE and NRC documents dealing with station blackout scenarios at BWRs as 'primers' going forward.
The most interesting document was from ORNL [Oak Ridge National Laboratory] on an experiment it conducted in 1993-94 to get details on how such an event would progress at a BWR - they chose Browns Ferry as their model. After the charts and diagrams and modeling data for setting the validity to Browns Ferry, it offers the details of what the experiment demonstrated. Diagrams, charts, graphs… these are all highly educational to interested people who would like to grok the thermodynamics of nuclear systems and appreciate the differences between them and other heat generating systems.
Additionally, these graphic results from an experiment actually conducted by ORNL - actually featuring the GE Mark I reactors at Browns Ferry - offer an excellent educational resource for those many interested, educated and capable Kossacks who WANT to understand what happened at Fukushima and where it's at right now. The aftermath is dependent upon what TEPCO and the Japanese government decide is bland enough for people to know, but that along with more honest information coming in from citizen and Greenpeace monitors, ex-heads of the ministry and academic 'experts' who can't condone government actions do give a general gist that can be followed fairly well if the baseline grasp of the dynamics is in-mind.
In the end, I offer all this because I agree with the head of the U.S. NRC and Michio Ishikawa (and a few other 'watchers' out in the wider world) that the three reactor cores at Fukushima are as completely melted as they're going to get. Have been since March. The corium has likely melted through the vessel bottoms into the primary containment drywell in at least two of them, probably all three. This would explain many things, including the apparent (reported) diminishing of immediate radiation levels on-site, as the corium is actually better shielded in the drywell as opposed to a breached vessel up high. It also means the 'flood the containment' tactic less dangerous, as they don't have to go to normal core level, they only have to go to the bottom segment of the vessel in order to provide cooling to what's left of the cores.
Apart from all other problems at the plants (and there are many), it looks less and less likely every day that the corium will melt all the way to the water table. That is encouraging, no one wants to see the worst nuclear catastrophe since nukes were invented get significantly worse than it already is. God willing, it won't get significantly worse (even though it conceivably could).
"God willing." Kind of a strange phrase given the monstrous earthquake and tsunami that started this catastrophe, classified by most insurers as "Acts of God." A similar station blackout at Browns Ferry ~7 weeks later caused by our own home-grown natural disaster scenario (massive tornado outbreak that kills lots of people and wipes out transmission capabilities) is enough to cause a double-take. When I realized ORNL had gamed this exact scenario nearly 20 years ago and come up with some data that would tend to make Fukushima a foregone conclusion even before all the buildings had finished blowing themselves to smithereens (note the hydrogen production graph in the ORNL document), it's spine-chilling.
Maybe God's trying very hard to tell us something our hard heads and myriad distractions make us normally deaf to? If so - and it takes this much death and destruction just to get our attention - it's a sure bet we probably won't get any future warnings before the worst of the worst case scenarios happens. I consider ourselves warned. As clearly as any warning could possibly be made.
* Illustrations from the ORNL document linked.