查了維基，快堆和熱中子堆都可以是第四代。樓主那個算是VHTR麽？南非那個下馬了。

http://en.wikipedia.org/wiki/Generation_IV_reactor

The very high temperature reactor concept uses a graphite-moderated core with a once-through uranium fuel cycle, using helium or molten salt as the coolant. This reactor design envisions an outlet temperature of 1,000 °C. The reactor core can be either a prismatic-block or a pebble bed reactor design. The high temperatures enable applications such as process heat or hydrogen production via the thermochemical iodine-sulfur process. It would also be passively safe.

The planned construction of the first VHTR, the South African PBMR (pebble bed modular reactor), lost government funding in February, 2010.[1] A pronounced increase of costs and concerns about possible unexpected technical problems had discouraged potential investors and customers.