A series of runs was performed in which waste processing facility influent was spiked with americium-241, neptunium-237, and uranium-233 and run through the ultrafiltration and reverse osmosis (RO) units. The results of these experiments show that the ultrafiltration membranes are ionic dependent, whereas the RO unit is not. Membrane irradiation studies have been started. Continuous run parameters are being verified through a series of experiments. The small laboratory column tests were continued this quarter on several adsorbents. Decontamination factors were calculated for these adsorbents in removing neptunium-237 and americium-241 from waste solutions. Tests were continued with the 2-in. Engineering Columns using ultrafiltration product spiked with uranium-233. A 6-in. diameter column was installed in the combined raffinate line from the three Engineering Columns. This ''mixed bed'' column will polish the waste solution that is returned to the waste processing facility tanks. A quality control program was started this quarter.

A method was developed that allows the mode-locking process to go to its steady state condition before the laser is Q-switched. This is done by pumping the laser quasi-cw for about 5 ms. During this time, the loss in the Q-switch is such that the laser will just slightly go above threshold. The active modulator is on during this time, and the laser oscillates quasi-cw for a period long enough to obtain stable transform-limited short pulses. At the end of this prelase period, the laser is Q-switched, and a train of stable, short pulses is obtained.