In the 1980s, a series of critical experiments referred to as the Haut Taux de Combustion (HTC)
experiments was conducted by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) at the
experimental criticality facility in Valduc, France. The plutonium-to- uranium ratio and the isotopic
compositions of both the uranium and plutonium used in the simulated fuel rods were designed to be
similar to what would be found in a typical pressurized-water reactor fuel assembly that initially had an

This paper provides a brief description of the United States Nuclear Regulatory Commission (NRC) and its regulatory process for the current nuclear fuel cycle for light water power reactors (LWRs). It focuses on the regulatory framework for the licensing of facilities in the fuel cycle. The first part of the paper provides an overview of the NRC and its regulatory program including a description of its organization, function, authority, and responsibilities.

Burnup credit (BUC) is a concept applied in the criticality safety analysis of spent nuclear fuel
in which credit or partial credit is taken for the reduced reactivity worth of the fuel due to both fissile
depletion and the buildup of actinides and fission products that act as net neutron absorbers.
Typically, a two-step process is applied in BUC analysis: first, depletion calculations are performed
to estimate the isotopic content of spent fuel based on its burnup history; second, three-dimensional