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/ > > > > >
