NUCLEAR COMMISSION ORDERS A SHUTDOWN FOR SOME REACTORS
Nuclear Regulatory Comm agrees to temporary shutdown of all Babcock & Wilcox nuclear reactors after utilities agree to modify safety equipment and operating procedures; agrees to permit 2 such reactors at Oconee, SC, to continue operating for a while in order to prevent possible electric power shortages in South Carolina, North Carolina and Virginia; Babcock & Wilcox says action is unncessary, but says it is preferable to forced immediate shutdown initially recommended by comm staff; Harold R Denton of NRC and William S Lee, pres of Duke Power, operator of Oconee plants, comment; instrument failure at 3 Mile Island, Pa, plant forces Fed and utility officials to switch to different method of cooling crippled facility; some radiation escapes into atmosphere, but at apparently harmless levels; illus of Oconee plant and demonstration at Rancho Seco, Calif, plant (M)