Records show that difficulty has been encountered with the discharge of two tubes in B Pile, twelve in the D Pile, and fifteen in the F Pile during the period from initial start-up until March 15, 1948. In sixteen cases the tubes have been replaced, six of the tubes which were in the fringe have been made air tubes, four did not warrant replacement, and three are to be replaced in the future. General statistics for these twenty-nine tubes are presented with additional details in this report.

Activities for the month of February are as follows: (1) calculations of reactivity and temperature limits; (2) calculations of operating levels of D pile if reduced in size; (3) symposium on power coefficients; (4) test of new vertical (safety) rods; (4) metal quality studies; (5) status of process tube ionization chamber failures; (6) reactivity balance of each of operating piles; (7) graphite testing; (8) water activity calculations; (9) pile shielding; (10) radioactivity of titanium; and (11) critical mass experiments.

None