Continued research is reported in the areas of intrinsic radioactive tracers for industrial process control and the effects of structural factors on radioinduced graft polymerization. The use of Be-- Po neutron sources for production of short-lived isotopes is being investigated. Data are included on the effects of target volume, high-Z scattering media, target-isotope concentration, and macroscopic cross-section on speciflc and total activation produced with a 10-curie source. Research on graft-polyerization concerning the effects of structure on freetinued. Results indicate that the radical formed in a variety of substituted methacrylate polymers is the same in all cases. (J.R.D.)

Calculations are made to determine the safe steadystate power operating limits of the Spert III reactor from the viewpoint of fuel plate burnout. A computer program is developed for the IBM 704 to aid in these calculations. The Bettis design departure from nucleate boiling (DNB) equation is used in conjunction with the LeTourneau and Grimble method of hot channel'' analysis in the development of the calculations. For cases where DNB occurs in the bulk boiling region, a modified Martinelli-Nelson twophase flow correlation and some experimental singlephase pressure drop data are employed. DNB for a typical operating condition of 550 deg F inlet temperature and 2500 psig is computed to check the code. The results of the sample calculation show that at a steady- state power level of 60 Mw (maximum design power) the minimum flow rate required to prevent DNB is approximately 8000 gpm. (auth)

The stated objective of the SNAP-50 reactor and primary system development program is the design, fabrication, development and test operation of a series of reactors and associated equipment leading to a fully qualified and accepted SNAP-50 flight reactor and primary system.