Slashdot Mirror
TEPCO Unveils Plan To Deal With Fukushima Crisis
RedEaredSlider writes "Tokyo Electric Power Co. unveiled its plan for dealing with the crisis at the Fukushima Daiichi nuclear power plant, the worst nuclear disaster since Chernobyl. TEPCO said the radiation levels should drop over the next three months. It will take about six months for the reactors to achieve 'cold shutdown' in which the temperature of the water inside the reactor is less than 100 degrees Celsius (212 F). The current plan for cooling the reactors will mean injecting nitrogen into the reactor pressure vessel. All four damaged reactors experienced hydrogen explosions when water, heated by nuclear fuel, turned to steam and reacted with the zirconium alloy cladding of the fuel rods. Hydrogen, when exposed to oxygen, combusts. Nitrogen is an inert gas, so TEPCO hopes that it will prevent further explosions."
Liquid nitrogen is less effective than water at extracting heat. I ran through the calcs a few weeks ago:
http://news.slashdot.org/comments.pl?sid=2039038&cid=35501128
It's no noble gas; but N2 is pretty mild mannered. Nitrogen fixation generally requires either really clever enzymes(as with nitrogen fixing bacteria) or fairly abusive temperature and pressure along with a catalyst(as with the Haber Process). It is commonly used as a shield gas for welding of many of the less zesty metals; because it is probably the best-placed material on the cost/inertness curve. Nitrogen, liquid or compressed gas, is dirt cheap compared to any genuinely inert gas, and is inert enough for quite a few applications.
Compounds with a high proportion of nitrogen atoms, on the other hand, are to be considered guilty until someone who loves their fingers less than you do has finished proving them innocent...
So you don't think the metal pressure vessels, piping and fittings corrode and degrade under conditions of very high temperature, pressure, and nuclear radiation? They will never be as safe as the day they were built because it's not practical to inspect constantly and thoroughly enough to catch every single flaw before it becomes the least bit dangerous. The difference is if a coal, oil, or gas plant blows a pipe, a bunch of non-radioactive steam escapes, maybe kills some personnel on site, and maybe causes some fairly expensive damage. In a nuclear plant, there is always that possibility that a failure may progress to the catastrophic complete devastation of the entire site and some of the surrounding area.