Re: [tlug] How much of radiations measured in Central Tokyo?

[Josh Glover <jmglov@example.com>]

On 15 March 2011 17:19, Stephen J. Turnbull <stephenjturnbull@example.com> wrote:

> Bad things are happening there, and they could get worse.  But there are
> competent people on the job, and it really seems that they know what they're
> doing (like putting out a big fire, cooling down a reactor takes time).  It's
> likely that they'll do the job.

And competent nuclear scientists are confident that even a full-on
core meltdown would be appropriately contained. As Stephen has
previously said, these are not Soviet plants, and they were designed
with defence in depth, to keep the radioactive core completely
isolated even in the event of a meltdown. Plant technicians are
trained for things that "should never happen", and the plants
themselves have safety measures for every conceivable failure. Of
course, there are always unconceivable failures, but it looks like the
Fukushima plant has already failed safe enough to stop worrying about
background radiation, unless you're there working on the core.

The main nuclear reaction (using fissile uranium) was stopped by the
control rods long ago. The control rods are suspended *above* the
fuel, so that a total loss of power will result in them dropping down
and halting the main reaction, courtesy of gravity. However, in
Fukushima, as in all the plants that shut down as a result of the
earthquake, the rods were lowered by the automatic anti-earthquake
safety system *before* the tsunami killed the emergency diesel
generations and the backup batteries were depleted.

Radioactive material is dangerous, and the nuclear power industry has
over-engineered plants accordingly. A rupture of the core containment
system is very unlikely in any Western reactor design since the 60s or
so, and the Japanese Boiling Water Reactors were built in the 70s.

If you have not read this yet, it should calm your fears:

http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/

-- 
Cheers,
Josh