Fukushima No. 4 reactor saved by upgrade mishap [View all]

[kristopher]

Yet another instance where blind luck - not planning, not safety design - was what determined the severity of the meltdowns. They made a mistake in sizing a piece of equipment needed for overhauling the reactor, the end result of which was that there was a large quantity of water available which actually should not have been there to cool #4's fuel pool.

Which side will luck be on next time?

Fukushima No. 4 reactor saved by upgrade mishap
March 08, 2012
By TOSHIHIRO OKUYAMA / Staff Writer

Bungled replacement work and a chance opening in a separator gate very likely saved the No. 4 reactor at the Fukushima No. 1 nuclear power plant from descending into a nightmarish situation, it has been learned.

The governments of Japan and the United States were worried that overheating and the decay of spent fuel rods at the No. 4 reactor could trigger catastrophic developments following the disastrous events of last March 11.

It appears now that the coincidental occurrence of the delayed replacement work and the opening in the separator helped avert the potential scenario of a full-blown meltdown.

The core shroud, a large structure in the reactor core, was undergoing...

http://ajw.asahi.com/article/0311disaster/fukushima/AJ201203080066