Marla Cervantes wrote:

Monday, October 22, 2018, 17:55  UO2/C green was prepared , September 24, 2018 Initial UO2 powder used = 50.11 g (Inventory R-01032A, UO2 + bottle = 374.03 g before use) Graphite powder used = 10.13 g Green cast dried UO2/C + organic mass = 62.45 g  The green was rolled up and wrapped in a piece of graphite sheet. The Ta-target boat was wrapped with 3-layers of heat shield [2 reused, 1 new] and installed in evap1. Currently pumping down  Tuesday, October 23, 2018, 15:38 IGP1 = 2.44e-6 Torr, Tapped to 60 A at 10A/10s with 20 s waiting every 10 A, Waited 28 min to vacuum to stabilize, tapped to 80 A at 10A/10s with 20 s waiting every 10 A, max pressure 7x10-3 Torr, waited 50 min to vacuum to drop Tapped to 100 A at 10A/10s with 20 s waiting every 10 A, max pressure 4x10-2 Torr, tapped current to 80 A, The pressure was dropping, when it was at 2x10-2 Torr, the current tripped off. IGP1 = 1x10-4 Torr Tapped back to 60 A at 10A/10s with 20 s waiting every 10 A, waited 5 min to tap to 80 A at same rate waited 5 min to tap to 100 A at same rate waited 25 min to vacuum to drop from 2e-2 Torr to 8e-4Torr Tapped to 110 A at same rate waited 3 min  to tap to 120 A at same rate waited 1 min  to tap to 130 A at same rate waited 1 min  to tap to 140 A at same rate   waited 15 min to pressure to drop from 6e-2 Torr to 7e-4 Torr   Changing manual rate to 10A/10s with waiting periods of 1 min, current was increased from 140 A to 260 A with this rate.   Changing manual rate to 20A/10s with waiting periods of 30 s, current was increased from 260 A to 480 A with this rate.   Waiting 4 min for the pressure to increase.   Changing the rate to 5A/30s, tapped until 510 A,   Changing the waiting period to 1 min, kept tapping to 530 A,   The pressure was dropping, when it was at 2x10-2 Torr, the current tripped off   The vacuum limit is 5e-1 Torr, and the pressure was dropping, there was no reason for the current to trip.   The pumps seems to be fine in the hot lab.

 Wednesday, October 24, 2018, 17:51

Rod from controls checked on the system, seems that the controls are not the cause of the trip

Rod suggested that the power supply might be overheating, 

thermocouples were installed on the surface of the power supply to register the temperature during the process

Tapping the current up again at accelerated rate see spread sheet for details.

Since pressure was not decreasing the current was increased to 595 A (rate 1A/min) [see figure CT-2]

The power supply's maximum temperature was 32.7 C which is a difference of 9.7 degrees with respect to the initial temperature. 

The target will remain at maximum temperature overnight.