Korea Hydro & Nuclear Power Co. (KHNP), the state-run nuclear power operator, said Wednesday that it will invest 6 trillion won (US$5.6 billion) in developing a safer reactor by 2020 as part of its efforts to beef up the country\'s nuclear safety. KHNP said it will earmark up to 7 percent of its revenue for the project every year with some 3,900 experts participating. The company posted 5.8 trillion won in revenue last year.