On 31/10/2013 10:26, The Natural Philosopher wrote:
On 30/10/13 22:36, newshound wrote:
On 30/10/2013 22:27, Andrew Gabriel wrote:
In article ,
The Natural Philosopher writes:
the rectorr would have been scrammed as part of the trip proecss,
stopping te chain reaction instantly, and the only nucelar issues left
aredeacy heat in te fuel rods, cibered by curculkatin te gas through te
core. A cannot remember where AGRS use convection or pumped gas but
they
are very safe designs.

http://en.wikipedia.org/wiki/Advance...cooled_reactor

ah yes, forced water and gas coooling, so they need the pumps.

They can get away without pumps in an emergency - convection cooling
by the gas alone can take away the power generated when shutdown.
That's one of their key safety design features.

Correct. And things happen relatively slowly with some thousands of tons
of graphite to heat up.

no, in fact they dont. An its not thousands, its hundreds at most.

The reasons for the delays are more about the nuclear-chemical
consequences of shutting down in a hurry.


Well it is much slower than in a water reactor, partly because of the
lower fuel rating and partly the greater mass of moderator in the UK plant.

I don't have the figures for AGRs to hand, but the Wylfa core contains
3740 tonnes of graphite. The AGR core is the same height, but certainly
quite a bit smaller in diameter. It must be close to a thousand tons.