*Any reactor larger than ca. 400 MWe needs active cooling system, because power output is larger that can be cooled down passively.*
A good nuclear reactor design should be air cooled. Such as design can be upscaled to handle any cool down heat capacity. *And there won't be reactor pressure vessel breach if active cooling fails.* A good nuclear reactor design should be unpressurized, with no pressure vessel required. A good reactor design should be modular and be easily expandable from very small to very large without design complications. Such a design was prototyped back in 1969 demonstrated for a year and was discarded for political reasons China took this prototype design as the starting point for their main line commercial nuclear reactor development. <jounivalko...@gmail.com> > > Any reactor larger than ca. 400 MWe needs active cooling system, because > power output is larger that can be cooled down passively. However, 300 MWe > and less can be cooled down after the shut down just submerging reactor > into water, hence they are inherently safe. And there won't be reactor > pressure vessel breach if active cooling fails. For example, Kursk's > nuclear reactor did not suffer any damage in the accident and it is still > fully operational reactor. It was kept cool by surrounding sea water. > > It would be best to have small modular reactors. However nowadays > politicians count nuclear power as a number reactors. Hence they allow > building new reactors one at the time and if number of individual reactors > is limited, industry of course will build the biggest reactor on the > market! > > For example, here in Finland politicians allowed to be build one (1) > nuclear reactor into Olkiluoto, and of course industry chose to build one > 1600 MWe EPR (world largest!) that is just waiting for Chernobyl/Fukushima > scale disaster if every planned backups fails like they did fail in > Chernobyl/Fukushima. Olkiluoto 3 EPR reactor was commercial failure, it is > now some five years delayed, mostly because of the safety issues that are > inherently extremely difficult and demanding for that scale reactor. > > It would be far more wise to build modular 5x300MWe reactors. Safety > issues are much cheaper and the grid reliability is higher (single module > can be maintained at the time while others are running), but it is almost > impossible to get licence for five (5) nuclear reactors in current > political atmosphere! > > —Jouni > > > On 3 Apr 2012, at 22:47, Jed Rothwell <jedrothw...@gmail.com> wrote: > > Axil Axil <janap...@gmail.com> wrote: > > I believe that the design of the Fukushima reactors were Pre-Three Mile >> Island. >> > > As far as I know, the design of the reactor itself is not at fault. The > accident was caused by the destruction of the backup power supplies. > > As far as I know, none of the commercial reactors now sold have passive > cooling after shutdown. So any reactor would have the same problem. Even > CANDU reactors have to be actively cooled. > > The Three Mile Island accident was caused by a defective reactor design, > with a stuck valve and a badly designed instrument panel. > > - Jed > >
