The ("Design and Construction Rules for Mechanical Components of PWR Nuclear Islands") is a major international industrial standard published by AFCEN . It provides technical rules for the mechanical components of pressurized water reactors (PWR). Official PDF Access and Download
Most nuclear operators (EDF, CEA, Framatome) will require the latest edition plus any applicable addenda. rcc-m pdf download
Some specific technical details are available through research papers and educational uploads: RCC-M code The ("Design and Construction Rules for