Abstract: Under the Power Expansion Program (PEP), modifications have been made to the Sodium Reactor Experiment (SRE) facility to improve plant reliability and permit an increase in power to 30 Mwt, with a reactor coolant outlet temperature up to 1200°F.

A simple, light-weight, split beam optical smoke densitometer is described.

Abstract: The removal of both SM-1 Core I high burnup elements from the SM-1 Core II and the insertion of two SM-1 Core I spare elements i their places are discussed. Nuclear and thermal characteristics of Core II with the change are presented and conclusion related to the change in hazard potential are made. If the core change indicated by this report is made, local peaking factors will be decreased and burnout ratios will be increased. This, of course, in itself leads to a more conservative estimate of core safety. There is no conceivable reason why this perturbation may not be safely made in the SM-1 Core II.

A commercially available electronic high vacuum pump has bee tested on various types of mass spectrometers used at the Oak Ridge Gaseous Diffusion Plant. Considerable savings in operating and maintenance costs can be realized from the use of this pump. the greatest savings result from the elimination of the cold trap required for the diffusion pump whether it is cooled by liquid nitrogen or by mechanical refrigeration. additional savings results from the fact that the pump currently is usually an adequate indication of the pressure in the spectrometer tube and that a continuously running mechanical fore pump is not required.