Plus-minus ratios for pion production by 340-Mev proton bombardment were measured at 13 Mev, 18 Mev, and 42 Mev with the use of the spiral orbit spectrometer.

At the present time, plants in the 100-500Mv size range are more numerous and carry the greatest portion (over 50%) of the total steam-electric plant load in the U.S. utilities industry. The contribution of plants of over 1,000-Mv capacity is increasing more rapidly than any other size clarification and at present represents about 10% of the total capacity. By 1962 the TVA will have six plants with capacities of over 1,000-Mv. The largest steam-electric plant in the U.S. is the TVA plant at Kingston, Tenn., with a nameplate capacity of 1,440-Mv. Turbine-generator units are also following a trend of ever-increasing size. In present construction, the 150-200 Mv size range for units is the most common and represents the greatest contribution to capacity. Two units of 500-Mv nameplate rating each, the largest in the U.S., are on order by the TVA, and an 800 Mv unit is contemplated.