Regulatory Role of the Reactor Accident Source Term

The reactor accident source term arises in two distinct ways in the US regulatory process. The first is the release of radioactive material to the environment during a hypothetical reactor accident. This source term is an input to models of radionuclide dispersal and accident consequences. It drives measures taken for emergency preparedness and accident response. It is a crucial element of Level III probabilistic risk assessments and also arises in the cost-benefit analyses of safety improvements that go beyond regulatory requirements to provide adequate protection of public health and safety. The second source term used in the regulatory process is the release of radioactive material to the reactor containment. This source term is used in the analysis of plant sites. It is a defense in depth measure to assess the adequacy of reactor containments and engineered safety systems. This source term also figures in the environmental qualification of equipment within the containment that must function following a design-basis accident. Most of the currently operating power reactors in the USA were designed an