Underground siting of nuclear power reactors

A preliminary study of reactor siting has evolved a new concept of undergrounding that calls for excavation of an open pit. The reactor containment structure can be built using conventional construction techniques. After construction, the reactor vessel is covered with backfill material of defined permeability and porosity. Calculations show that because of this controlled permeability, radioactive seepage is confined in the backfill should an accident rupture the containment structure. The required depth of burial for complete confinement of the radioactive release is on the order of 100 m. Even a few metres of selected backfill, however, provide a dramatic reduction in the consequences of a transient release of radioactivity due to filtration and adsorption. In addition, backfill makes the reactor invulnerable to tornadoes and falling objects. Solving the containment issue in this economic manner makes close-in, metropolitan reactor siting a distinct possibility. (author)