nuclear-news

Man made corium lava – from Fukushima, toxic for centuries

Wired: ‘Healthy debate’ about location of Fukushima corium — Lava can melt a foot of concrete per hour — Cooling with water may not stop corium flow Title: The Most Dangerous (Man-Made) Lava Flow http://enenews.com/wired-healthy-debate-about-where-fukushima-coriums-are-lava-can-melt-a-foot-of-concrete-per-hour-cooling-with-water-may-not-stop-corium-flow
Source: Wired
Author: Erik Klemetti
Date: April 18, 2013 at 11:45a ET
h/t Room101
Title: The Most Dangerous (Man-Made) Lava Flow

[…] researchers at the Argonne National Lab have created corium in the laboratory […] They found that corium lava can melt upwards of 30 cm (12″) of concrete in 1 hour! This is why it is so important to know if a nuclear reactor accident has gone into true “meltdown” as the corium lava will rapidly melt its way through the inner containment vessels (or more) in a matter of hours unless it can be cooled again.

However, results from these CCI (core-concrete interaction) experiments, suggest that cooling with water may not be sufficient to stop corium from melting the concrete. One thing to remember — much of the melting of concrete during a meltdown occurs within minutes to hours, so keeping the core cool is vital for stopping the corium for breaching that containment vessel.

[…] TEPCO, the Japanese energy company who ran Fukushima Dai’ichi, claims that the corium didn’t breach the outer wall of the containment vessel (although there is a healthy debate about this).  […]

So, why is corium so dangerous? Well, even long after the flow has stopped, that lava will be highly radioactive for decades to centuries (along with the surrounding countryside if radioactive material made it out of the containment vessel) as the various radioactive materials in the lava decay. In fact, we don’t even have pictures of the corium lava from Fukushima Dai’ichi due to the high levels of radioactivity near the reactor. […]

See also: Analysis: Melted fuel completely penetrated concrete in under 15 hours at GE Mark I — Shows little decline in speed (CHART)

April 20, 2013 - Posted by Christina Macpherson | Fukushima 2013, Reference