Another link, explaining the function of the (now missing due to the explosion) suppression pool at Unit 2: http://www.ucsusa.org/nuclear_power/nuclear_power_risk/safety/concerns-about-relying-on.html
It seems the only way to avoid a definitive rupture of the containment vessel is by venting more and more of the radioactive steam. This is quickly going from worse to worst. On 03/15/2011 06:19 AM, Mauro Lacy wrote: > Information related to the internal explosion in unit 2 at Fukushima > 1, by Yoichi Shimatsu: > http://newamericamedia.org/2011/03/tohoku-quake-and-tsunami-monitoring-internal-combustion.php > > From the article: > "That's the bad news. The even worse news is that the explosive force > of the internal blast reflected off the outer surface of the container > chamber, thus focusing a surge of massive pressure against the core > reactor vessel. There is a strong likelihood, yet to be determined by > TEPCO, of damage to the steel alloy of the reactor vessel. So far, any > micro-fissures in the core reaction have apparently not yet leaked > heavily. " > > > On 03/15/2011 05:02 AM, Horace Heffner wrote: >> This is an expanded and corrected version of the prior post in this >> thread. >> >> I think the primary danger from Fukushima 1 lies in the fact it uses >> MOX fuel (mixed oxide fuel, the oxides being of uranium and >> plutonium). Also, there is a vast amount of stored fuel outside all >> the reactor containment vessels. There is at this point no telling >> what the condition of the stored fuel rods is. In addition, >> plutonium produces a lot of neutrons, which increases the chances for >> spontaneous chain reactions if the fuel melts into a blob. These >> would be small explosions or thermal excursions, but still very >> dangerous, and possibly repetitive if the material is located in a >> confined space, like a hole bored into the ground. >> >> See: >> >> http://www.washingtonpost.com/business/economy/nuclear-crisis-deepens- >> as-third-reactor-loses-cooling-capacity/2011/03/14/ABk6rQV_story.html >> >> http://tinyurl.com/67tp62y >> >> "A commercial satellite photo of the complex showed piles of debris >> on top of units 1 and 3, which raised new fears about the condition >> of the pools where spent fuel is stored, especially at unit 1, where >> a design by General Electric placed the pool on top of the reactor >> but below the outer structure that was destroyed. The ability of >> workers to assess the damage was hindered by fears that another >> explosion might occur." >> >> "In March 2010, 1,760 tons of spent fuel was stored in the six pools >> — 84 percent of capacity, according to Tokyo Electric." >> >> That is over 250,000 kg of uranium (plus possibly some plutonium in >> the case of MOX) per storage pool on average. What is that going to >> do if it melts into a blob and starts boring a hole into the earth? >> That's a rhetorical question. For many answers google(China syndrome). >> >> That 250,000 kg contains many times the fissionable material in an >> atom bomb. This is a big problem even given it is almost all U238. >> MOX fuel, used in unit 3, is a *huge* problem. Plutonium is one of >> the most radiologically poisonous materials on earth. Pu242 has a >> half-life of 376,000 years. The atomic bomb Little Boy, dropped on >> Hiroshima, had 64 kg of uranium. Fat Man, dropped on Nagasaki, >> contained 6.2 kg of plutonium. For background information on Fat Man >> and Little Boy see wikipedia. >> >> Material that melts down inside the reactor steel containment has a >> chance of cooling down, due to the presence of control rod material, >> which should end up in the mess along with the fuel glob. However, >> spent fuel storage does not include control rods. It amounts to a >> water pool with storage racks. If the pool leaks the fuel rods can >> be exposed. >> >> Lesson learned too late: don't store fuel rods near reactors that >> have to be cooled and might explode. Second lesson: MOX fuels are a >> very bad idea in commercial power reactors. >> >> "Also notable, according to information on the website of Tokyo >> Electric Power Co., which operates the Fukushima facility, more than >> 200 tons of spent fuel is stored [away from the reactors] in casks." >> See: >> >> http://www.propublica.org/article/status-of-spent-nuclear-fuel-in- >> question-at-crippled-japanese-power-plant >> >> http://tinyurl.com/4taefqa >> >> The above web site has a good satellite photo taken before Fukushima >> No 2 blew. There are many amateur model airplane and drone builders >> that could get much closer much higher resolution photos. What is >> really needed are little robots to explore inside. The US Navy >> should be able to provide some help along those lines. >> >> The Fukushima reactors typically are loaded with 56 to 91 tons of >> fuel. See table on page 1 (called page 70) of: >> >> http://www.tepco.co.jp/en/challenge/energy/pdf-1/nuclear-e.pdf >> >> If the fuel loaded into reactor 3 is 0.5% plutonium, then that is >> about 280 kg of plutonium, about 45 times that in the Fat Man bomb. >> >> If a China SYndrome develops, then huge amounts of soil material can >> become neutron activated, made radioactive, so many additinal tons of >> radiologically toxic material could end up in the environment. >> >> What has happened and is happening in Japan is deeply saddening. The >> photos of the tsunami damage are heart wrenching. I hope for a quick >> resolution to the nuclear problems and for a minimal release of >> material. More pain in this situation is just unthinkable. However, >> it appears the dangers are great and not fully appreciated by the >> public, and there may be a need to calmly but rapidly prepare for the >> worst. >> >> Best regards, >> >> Horace Heffner >> http://www.mtaonline.net/~hheffner/ <http://www.mtaonline.net/%7Ehheffner/> >> >> >> >> >> >
