The situation at Japan’s Fukushima Daiichi nuclear power plant has become extremely unnerving. The Tokyo Electric Power Company has now admitted that the spent fuel rods could go critical – that is, a nuclear chain reaction could restart.
“TEPCO said it is considering spraying Boric Acid by helicopter to try and prevent spent fuel-rods from reaching criticality again….” Turns out that sea-water for sure would slow the fission product Neutrons and allow them to be absorbed by other fuel components thus speeding up the chain reaction. “Without water the neutrons move to fast and are not absorbed …”
That’s different …
Hence the company’s proposal to add boric acid, which would mop up the neutrons and hopefully stave off the reactivation of a nuclear reaction. If this did happen, it does not mean there would be a nuclear explosion, but the rods would heat up, the zirconium cladding would probably split, and the likely release of radioactive material into the atmosphere would be significantly higher.
From Source:
NEW SCIENTIST.com WED, 18.20 GMThttp://www.newscientist.com/blogs/shortsharpscience/2011/03/nuclear-crisis-radioactive-fue.htmlIn addition ...
‘We have known since yesterday that the reactors themselves were coming under control, and that the biggest threat came from the spent fuel ponds, where the water level has fallen and temperatures have risen. That could lead to the stored fuel rods breaking open, releasing their radioactive contents.
”The possibility of recriticality is not zero,” TEPCO said as it announced the envisaged step against a possible fall in water levels in a pool storing the rods that would leave them exposed.’
