Concepts of small reactors

As a result of the Three Mile Island and Chernobyl accidents the safety of nuclear reactors have led to passive and inherent safety. That is, we should rely on the laws of nature, whether they be hydraulic, fluid diodes or gravity. Fundamentally there are only two requirements. The first is to make sure that the nuclear core power does not exceed a certain level. The second is to remove the core heat. According to Forsberg, five characteristics can be identified, which he calls PRIME (Passive safety, Resilient operation, Inherent safety, Malevolence resistance, and Extended safety), and should prevent major accidents. The best concept for advanced reactors is to make them essentially PRIME. In addition there are many options to realize the PRIME; natural circulation, balance between hydraulic pressures, fluid diodes, super containments. (author). 13 refs., 1 tab