2. SMR for water reactors

The objective of a new nuclear offering that would complement existing power plants and be available as quickly as possible has led many designers to opt for a tried-and-tested reactor technology, the pressurized water reactor or PWR technology, the most widely used in the world for power plants and naval propulsion reactors.

Boiling water reactors (BWR), the other mature technology but much less widely deployed around the world, is, with one exception, not being considered by designers, probably for the following reasons:

• a design with disadvantages such as the second containment barrier extended to the conventional part (with risk of contamination), the mechanisms under the vessel (with penetrations in the bottom of the vessel), and a control system with instability domains;

• a sector...