Neutron fluence monitoring for subsequent license renewal

The U.S. Nuclear Regulatory Commission (NRC) has been reviewing nuclear power plant license renewal applications for licensees seeking extended operation beyond their original 40-year operating licenses. The NRC has reviewed and approved applications for multiple licensees to continue operating up to 60 years from the issuance of their original operating license. Licensees have shown recent interest in continuing operation up to a total of 80 years, in accordance with the Atomic Energy Act of 1954, as amended. The NRC has been reviewing the technical and regulatory challenges for this subsequent license renewal period. This paper: (1) reviews experience and challenges in applying the NRC's regulatory framework regarding neutron fluence calculations to the broad variety of neutron fluence applications that support 60-year extended operating licenses, (2) explains the NRC's basis for developing an aging management program for fluence calculations for 80-year license terms, and (3) discusses planned improvements to regulatory guidance supporting the regulatory framework regarding neutron fluence calculations.