Alcator C-MOD Weekly Highlights May 7, 1996 The spring maintenance period continues. Work last week focused on the RF, divertor, cryopump, and magnet cooling systems. Nine out of ten outer divertor modules have been removed from the vessel and are being inspected, cleaned, partially disassembled, and readied for modification. An insert will be welded into the outer divertor support plate to improve the shear strength of the divertor mother bolts a factor of three to four. This change will allow plasma currents of over 1.5 MA to be achieved without damage to the outer divertor. The last divertor module which contains the outer divertor probe array is now being removed. Work continues on several other systems. Transmitter interconnect cables delivered from PPPL have been shortened and installed. Mechanical work on the RF PLC control rack is complete and wiring has begun. The east diagnostics stand extension is complete and is now ready for the relocation of diagnostic and control racks. The ECE and McPherson experiments have been moved back from the machine so that modifications to the pumping station can be made, and transfer lines for the cryopump installed. The four new TF cooling control valves have been installed along with new larger diameter manifolds. PLC software changes to control the new valves are under development. The prototype cryopump has been leak checked, instrumented, and successfully cooled down to LHe temperatures. The PLC hardware and software for monitoring the pump operation is also up and running. Automatic control of the cooldown via the PLC will be possible as soon as we receive new cryogenic control valves (due this week). Darren Garnier and Ying Wang successfully defended their theses last week. Darren's thesis title was "Lithium Pellet Injection Experiments on the Alcator C-Mod Tokamak" while Ying's was "A Study of Impurity Screening in Alcator C-Mod Plasmas". Martin Greenwald attended the ESnet steering committee meeting at LBNL (Berkeley, CA) last week.