Gross electricity output totalled 496,410 MWh in May, Krsko said in a statement posted on its website.
A total of 8.3 cubic metres of low and intermediate-level radioactive waste was stored in May, Krsko said.
Krsko NPP, located in Slovenia near the border with Croatia, generates some 40% of Slovenia's electricity output. It operates a Westinghouse pressurised light water reactor of 2,000 MW thermal power capacity.