Posted on 03/14/2011 6:39:05 AM PDT by Lil Flower
TOKYO, March 14 (Reuters) - Nuclear fuel rods at a quake-stricken Japanese nuclear reactor are now fully exposed, Jiji news agency said, quoting the plant's operator, Tokyo Eletcric Power Co .
(Excerpt) Read more at mobile.reuters.com ...
Thank you so much.
I am awed by the Japanese response to this series of cataclysmic events.
And given the Japanese architectural engineering prowess on display from all the video abounding showing how little structual damage occured despite the intense shaking of a very violent earthquake, them pressure containment vessels could withstand a direct hit of a small nuke right now and retain pressure integrity AFAIC.
There's no way any meltage of the core occured. There is undoubtedly deformation of the fuel and moderator rod assembly, i.e., warpage due to unmitigated intense heat of the nuclear pile while it was uncovered for a short time (as the coolant bled off).
Even so, the nuclear pile was never totally uncooled. Even IF the entire nuclear pile was only in contact with steam, the steam was still exchanging heat from the nuclear pile into the secondary torus water reervoir; all that's part of the calculated cooling design specs (albeit not optimal but within putative tolerances ostensibly to avoid outright core meltdown).
In fact, even in the Sci-Fi event the reactor core did melt in entirety, the secondary containment vessel is designed and constructed such that the molten slag of the entire nuclear core would be confined entirely within the secondary torus water reservoir (resting upon a graphite floor a meter thick acting as moderator). It might take a decade for that to cool, but there'd be no catastrophe.
There's no way for un-enriched fuel to go critical, and the graphite - along with the incorporated molten moderating rod material - would dampen over time whatever residual reaction was still occuring.
The design is American, not Japanese. So the design engineers were American, not Japanese.
Fukushima Dai-ichi #1 was designed in the 1960s. The engineers who worked on that are in their 70's, 80's, or perhaps 90's, or already passed away.
Most of the scenarios that are being discussed in this and other forums were considered by those engineers, 50 or more years ago. The earthquake was 7 times more powerful than the maximum that the reactors were designed to withstand, so that is currently putting more stress on the reactors and the operators.
The reactors were mostly built, operated, and maintained by the Japanese.
The reactors must be built, operated, and maintained correctly, or else the best design will not prevent a catastrophe.
It seems to me (not an expert) that the Japanese could benefit at this time from consulting, in particular, expert out-of-the-box thinking. Hopefully they will accept Immelt's offer of help.
One potential problem is that the market for BWRs dried up in the late 1970s, and along with it, the engineering talent that was responsible for the design of these BWRs in the US was permitted to disperse and attenuate decades ago. Some of the expertise was shared or transferred to the Japanese.
Because the reactors are now in unorthodox modes of shutdown under pathologically unusual circumstances, out-of-the-box thinking (eg, of the Apollo 13 variety) may be of particular value. In any case now it seems like an ideal time for the enineers and operators of all countries to work together to regain control of the situation.
No, there is no need to worry on the West Coast, or anywhere in America. Those in the immediate vicinity should be suited up, and I have heard that a dozen or so workers have shown signs of radiation sickness. However, the 12-kilometer evacuation area should be enough distance for safety, even if the rods are somehow exposed to the outside (that is, if the containment structure is destroyed). So far, the containment structure is intact; it will stay so even if the rods melt down, as shown by Three Mile Island. The ‘China Syndrome’ is a myth, and the Chernobyl disaster came from a completely different design.
I believe that ‘rods exposed’ means that the coolant has been steamed off the tops, which is why they’re pumping in seawater to replace it. It’s a disaster for the plant, since the reactor can’t be rebuilt after corrosion from the seawater or if the rods melt, but ‘meltdown’ doesn’t mean nuclear devastation for anybody else.
In short, pray for the workers, but don’t worry about your baby.
Thank you for the clarification.
“I understand 5 years til they could examine to see how far it had gone [three mile island] ... most were shell shocked with the discovery how bad it actually was.”
That’s correct. But despite the severity of the core meltdown, the three mile island problem was contained by the containment vessel. That’s very likely the result in Japan.
The big remaining danger is that the earthquake compromised one or more of the containment vessels. As long as that doesn’t happen, the loss of power in Japan from the loss of these reactors will kill a whole lot more people than the multiple meltdowns will.
I hope that they've ventilated the roof this time to disperse the H.
You could have helped out “Bill Nye the Science Guy” on CNN yesterday. The commentator asked him why they couldn’t use liquid nitrogen to cool the fuel rods. Nye said that it was a problem of portability, that LN2 wasn’t very portable, and besides, when you’re talking about the extreme temperatures of fuel rods, there’s no appreciable difference in the cooling temperature of water as compared to LN2. That’s why, says he.
Of course, right after that, the commentator asked him about what caused the hydrogen explosion in plant #1. Nye said, and this is pretty close to an exact quote: “Hydrogen explosion? That doesn’t make any sense. Someone must have confused hydrogen with helium. There couldn’t be a hydrogen explosion, it must have been helium.”
Holy crap...all I know about generating nuclear power is what I’ve learned on the internet in the last couple of days and even I about choked on my beverage when I heard him say that. He’s CNN’s special, super smart, science guy who’s going to teach the audience all about nuclear power? OMG. I looked him up on wikipedia to see what his credentials were, and his highest level of education is a B.S. Degree.
Bullshit. And that's as politely as I can put it.
Chernobyl was an absolute worst-case scenario with an uncontained nuclear reactor melting down, and the melted core flowed across the concrete in the basement, not down into the earth.
That blob there, photographed by a remote-operated camera, is melted corium - nuclear fuel mixed with other core materials. If you were standing right there you'd die an horrible but quick death from the heat and radiation.
And look at this - the melted core couldn't even melt this steel steam pipe, let alone the bedrock:
It just flowed out the pipe onto the floor.
The melted core is only generating enough heat to melt itself, not enough to melt much of what's around it. And the containment is designed so that a melted core does not collect into a blob and go critical to generate more heat, but rather to spread out and dissipate it to keep it from going super-critical.
Repeat after me: "The China Syndrome was just a movie. The China Syndrome was just a movie."
Sorry, my bad. The link I provided got mixed up with a different thread somehow. Argergrgrgrgr!!!!! (I only posted that all over the board today).
See:
http://www.freerepublic.com/focus/news/2688347/posts?page=7#7
“Are we ever going to get the real truth from the media? On anything? Hell, they think we the people are dumber than a box of rocks.”
... amd they are going to do all they can to keep us that way
I've operated PWR's commercially and in the Navy and have withheld commenting because my knowledge of BWR's is pretty limited. But I do know that a 72 hour (plus) loss of all AC power is one heck of a challenge, and we can only hope for the best.
Most of the chicken-little anti-nuclear types have an agenda that is not in the best energy interest of the US. Yes accidents can happen and multiple redundancy is necessary to prevent such from becoming beyond serious no matter the location. IMO in this country, location is the most important factor -- away from major earthquake faults and high enough about sea level to avoid a tsunami or flooding from a hurricane.
If playing it completely, absolutely, positively safe is the goal, then we don't build nuclear plants, live near a chemical plant or oil refinery, don't drive a car or fly in a plane; we build an underground home in tornado country and a concrete and steel residence on a hill in hurricane country. Risk is part of living; it can not be avoided. We spend big bucks in all aspects of commerce to reduce it (some of which is beyond the pale due to sue happy tort lawyers). What one needs to do is to evaluate risk objectively and not listen to those who either downplay it or hype it. Those that do have other agendas.
Post of the day!
The containment vessels at these plants are designed precisely to contain a complete meltdown. For one thing, one of the things that keeps the reactor core so hot is that it’s in a tight space and heat exchange is difficult, but if there’s a full meltdown the slag would settle across a very wide area in the containment vessel and cool relatively quickly. The “China Syndrome” scenario is a hypothetical, requires a worst-case scenario that is likely impossible at a Western-designr (much less a Western reactor that has been subject to emergency cooling procedures for days) and the “explosion when it hits groundwater” scenario appears to be from the movie “China Syndrome” itself. Plus, plutonium use in commercial reactors is rare and the rectors the Japanese are having trouble with are uranium powered.
I agree - I'm not nuclear at all, but I am electrical (transmission) and there are significant reasons that we give top priority to providing off-site power to nuclear plants even though they have redundant on-site power sources. What we are seeing at Fukushima right now illustrates that need well.
http://www.nisa.meti.go.jp/english/files/en20110315-1.pdf
"(2) Readings at monitoring posts
The measurement of radioactive materials in the environmental monitoring area near the site boundary conducted by a monitoring car in considering the wind flow, confirmed the increase in the radioactivity compared to the radioactivity at 07:30, March 14.
MP3 (Monitoring at North West of Site Boundary for Unit 2) : 231.1 micro Sv/h (14:30 March 14)
MP4 (Monitoring at north- west of Site Boundary for Unit 2 : 56.4 micro Sv/h(04:08 March 14)→29.8 micro Sv/h(14:14 March 14)
MP5 (Monitoring at north-west Site Boundary for Unit 2) 6.1 micro Sv/h(14:02 March 14)
MP6 (Monitoring at the west –southwest Site Boundary for Unit 2) 3.70 micro Sv/h(16:10 March 14) →4.2 micro Sv/h(12:34 March 14)
MP7 (Monitoring at the west –southwest Site Boundary for Unit 2) 6.1 micro Sv/h (12:16, March 14) (3)
Wind direction/wind speed (as of 14:14, March 14) at MP-4 Wind direction: North North West Wind Speed: 2.6 m/s"
Also has some reactor pressures, water levels and other info.
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