The U.S. Nuclear Regulatory Commission (NRC) has issued a new Regulatory Guide (RG) 1.237, titled "Guidance for Changes During Construction for Nuclear Power Plants Being Constructed Under a Combined License Referencing a Certified Design Under 10 CFR part 52." This guide provides an approved process for making design changes to structures, systems, and components of nuclear plants under construction. The document also mentions that it does not impose mandatory compliance on licensees and would not constitute a backfit or forward fit. The guide is accessible online alongside related documents for public review.
Simple Explanation
The U.S. Nuclear Regulatory Commission has made a new guide to help people who build nuclear power plants know how to safely change their designs as they build. It's not mandatory to follow these rules, but they show a good way to do it if you choose to.