[en] Nuclear fuel cycle facilities, like much of the nuclear industry, are increasingly relying on digital instrumentation and control (DI and C) systems such as programmable logic controllers (PLCs) to maintain system variables for both production and safety purposes. Fuel cycle manufacturing processes are increasingly automated and relying on active engineered controls. Compliance with the double contingency principle requires that DI and C trains credited for criticality safety are independent. The additional requirements imposed as part of performing an Integrated Safety Analysis (ISA) in accordance with Title 10 of the Code of Federal Regulations (10 CFR) Part 70, Subpart H, mean that such DI and C systems must meet more stringent requirements than would otherwise be required to meet industry standards. This paper discusses the current status of the U.S. Nuclear Regulatory Commission's (NRC's) Digital I and C Working Group, and the requirements that would be imposed on such systems are a result of having to comply with the double contingency principle and the performance requirements of 10 CFR 70.61. Existing applicable NRC Interim Staff Guidance is summarized, and several case studies from ISA technical reviews are presented. (authors)