Well, it does seem to be where the explosion occured though. I just found http://www.nei.org/filefolder/BoilingWaterReactorDesign.jpg" [Broken] which at least seems to say as much. Although there seems to be a lot of conflicting information out there; one report claimed it occurred between the outside wall and a steel containment wall, which I'd interpreted as a Mark-III kind of containment, which isn't correct for the Fukushima reactor.The upper level of containment, the metal walls and roof, was destroyed. That structure is over the inner containment, which is reinforced concrete. I believe the reinforced containment had the pressure increase, which was vented. The venting would be through those stacks (towers) that one sees behind (to the west of) the units. Venting into the upper containment would not be the case as far as I know.
Yup, it'd require heavy investments though. A friend of mine was until recently involved in the upgrades in-progress at http://en.wikipedia.org/wiki/Oskarshamn_Nuclear_Power_Plant" [Broken], which is a BWR contemporary to Fukushima (although it's a different, ASEA design)In theory though, it's life could have been extended another 20 years.
The structure that was destroyed does contain the crane to lift the containment cover and is used during fueling operations. I'm not sure if it is considered secondary containment, but I do believe that it is a bit more secure than a simple metal enclosure. During refueling operations there is a small amount of radioactivity present and I believe the environment within the top portion of the building is controlled and not freely vented to the outside.It also houses the crane(s) to lift the containment cover and vessel components. I haven't seen pictures of the crane.
I think I read on TEPCO's, (Tokyo Electric Power Co.), website http://www.tepco.co.jp/en/press/corp-com/release/index-e.html that they were using Fire Pumps to inject seawater into the reactor. These are probably portable diesel-powered pumps that they have somehow hooked up to the Emergency Core Cooling System (ECCS), either the Core Sprayer system or the Low-Pressure Core Injection (LPCI) system. I think they still do not have AC power at the site to power their permanently installed pumping systems.Are the pumps they are using to pump seawater for reactor cooling motor driven or steam turbine driven? Are these the pumps designed for this emergency cooling or an alternate configuration?
I had used the http://www.nisa.meti.go.jp/english/files/en20110313-3.pdf" [Broken]. The count rates are on page 13; "measured without shoes, though the first measurement exceeded 100,000 cpm" sounds like that was the highest reading the instrument could give.What exactly is the source of those numbers? The link provides several pdfs.
Indeed, this is up to a 1000 times background levels. Maybe this was the origin of news reports mentioning that factor.Normal background btw is about 1-2 cps (60-120 cpm). Background comes from normal solar/cosmic radiation, and natural sources such as granite, and long-lived isotopes like K-40.
It is not dangerous to have shoes on which give 100 000 counts per minute. Just take them off, rinse them, and your problem is solved. If it is on your body, just take a shower (if showers are working in the afflicted area).And I would further ask, "What exactly is the significance of those numbers?" Is that even a significant quantity of radiation?
Is one refering to Onagawa plant? What is meant by enhanced?Another indication that there was a major release of radioactivity: Dutch radio just reported that the enhanced radiation levels at Onaga would be due to wind-driven activity from Fukushima.
This reminds me of how the Chernobyl accident first became public when radiation monitors at a Swedish reactor showed high levels of radiation.
Yes, I meant the plant Onagawa plant. Levels were 21 microsievert or four times as much (depends on how one reads the information - maybe they have an alert level of 21 microSievert, levels were four times their alert threshold).Is one refering to Onagawa plant? What is meant by enhanced?
Sorry: microsievert per hour, according to http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=ja&tl=en&u=http://mainichi.jp/photo/news/20110314k0000m040057000c.html".microsievert per what? 21 uSv is 2.1 mR. Typical backgrounds are 1 mR/day.
The cited report mentions 21 Sv, but not the time period, hr or day or otherwise.Sorry: microsievert per hour, according to http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=ja&tl=en&u=http://mainichi.jp/photo/news/20110314k0000m040057000c.html".
My point is not that it would be terribly dangerous at Onagawa, but that the amount of activity released at Fukushima was massive.
We can't assume that, though. Particulate and aerosol releases can be very directional with well-concentrated plumes.The alleged source being the Fukushima Daiichi plant located approx 120 kilometers to the south. Given 120 kilometers of diffusion, assumedly by some sort of Brownian motion type process, the Fukushima release must have been very substantial.
Immediately after the quake, the control rods were automatically inserted, and the fission chain reaction stopped. The heat production now is due to decay of the radioactive fission products, and is only about 10 % of the power when the reactor is on.Guys. Supposed the fuel rods melted and become molten, do fission still occur in molten state or not anymore?
I know. But supposed the controls rods were not inserted and the fuel rods melt and become molten and there is a tough cement underneath that prevent further falling underneath the plant. Would the uranium still fission when it's already in the molten state or would fission only occur when the uranium is solid?Immediately after the quake, the control rods were automatically inserted, and the fission chain reaction stopped. The heat production now is due to decay of the radioactive fission products, and is only about 10 % of the power when the reactor is on.