In 2013 and 2014, the Korea Electric Power Corporation (Kepco) and its subsidiary Korea Hydro and Nuclear Power (KHNP) submitted the APR-1400 reactor design certification application to the US Nuclear Regulatory Commission (NRC). During the design certification process, the NRC determines whether a reactor design meets US safety requirements, independent of any specific power plant project. It is required before a reactor design can be used in the USA. In April this year, the NRC completed the application review and published their ruling in the Federal Register certifying the APR-1400 design. The ruling came into effect 120 days following publication. The certificate is valid for 15 years and can be extended for a further 15 years.