Main Question or Discussion Point
I heard and read several times that a pebble bed reactor is "safer" than a PWR or a BWR. However, I fail to figure out how. After all, light-water reactors also have negative temperature coefficients, which seem to be the "invention" that makes the pebble bed reactor "inherently safe". But I fail to see what's so fundamentally different between this type of reactor, and the old graphite-gas cooled reactors by the UK and the French, except that now, the reactor core is made out of pebbles instead of blocks...