This report addresses the semiannual progress report for the period ending on February 15, 1963.

Reactor water leaks cause outage time for locating and eliminating the leaks and for repairing damage paused by the vater that enters the reactor. The justification for equipment and process changes necessary for reducing the number of leaks and the resultant outage time is dependent on the number of leaks expected. This document presents an estimate of the future reactor water leak frequency and the average outage time charged to each leak. A water leak is defined as any entry of vater into the reactor moderator during operation. Future vater leaks are expected to result primarily from Van Stone flange failures and miscellaneous causes such as mechanical damage, fuel ruptures, and transverse cracks. It is assumed that continuous emphasis will be placed on corrosion monitoring to determine the tubes that must be replaced to prevent leaks because of internal and external corrosion. The number of water leaks is expected to average between 80 and 100 per year in the future. The normal-range of the number of leaks probably will be between 60 and 120 per year as a result of normal variation in the process tube physical condition. The number of outage hours charged per leak is expected to continue …

The research and development activities reported on are: enriched fuel (1.25% U{sup 235}), flex 2 code development, Pu burning and recycle, single tube fuel element, heavy isotope production, U{sup 233} -- Th{sup 232} fuel cycle, physics input for economic studies, Pu{sup 240} effective resonance integral, N-Reactor operator certification lectures, bases for control and nuclear instrumentation, and shield evaluation. (GHH)