The Central Argentina de Elementos Modulares (CAREM) design has been under development for a number of years and was first introduced at an IAEA conference in 1984. The Comision National de Energfa Atomica (CNEA) drew on its experience in the design of research reactors to develop CAREM with the primary goals of enhanced safety and reduced costs. It is a simplified integral design with natural circulation of the primary coolant. The prototype design has a capacity of 27 MWe and commercial-sized units are expected to have capacities of 100-300 MWe with forced circulation being employed for units greater than 150 MWe. The design uses self-pressurization, i. e. it does not use sprays or heaters to maintain normal system pressure. The core is composed of 61 hexagonal fuel assemblies with 108 fuel pins per assembly and 25 control rods, which are positioned using internal hydraulic control rod drive mechanisms. The primary coolant flows over the shell-side of 12 compact helical coil steam generators. On the secondary side, the feed water and output steam are collected into a common set of annular pipes that surrounds the reactor pressure vessel.

The CAREM design uses passive safety systems and anticipates a post-accident grace period of 36 hours without operator action or power. Several test facilities have been built to test novel components such as the hydraulic control rod drive mechanisms and validate the safety analysis methods. The CNEA received the support

of the Argentinian government in 2009 to construct the prototype plant adjacent to the existing Atucha nuclear site. Plant construction began in 2014. Key parameters and a representative graphic for the CAREM design are given in Figure 2.1. [1]