Laura Lambert wrote:

Laura Lambert wrote: Laura Lambert wrote: Laura Lambert wrote:  Tuesday, May 23, 2017, 14:42 UO2/C green was prepared May 16th, 2017. The cast peeled off the glass nicely May 17th, 2017. Initial UO2 powder used = 50.25g (Inventory R-01032A, UO2 + bottle = 876.80g before use) Graphite powder used = 10.32g Green cast dried UO2/C + organic mass = 61.70g  The green was rolled up and wrapped in a piece of graphite sheet. The Ta-target boat was wrapped with 1 long layer of heat shield and installed in evap1 today. Chamber pumped down today. Target boat will be ramped up to 520A at the rate of 0.1A/min. Vacuum limit stop at 5.0e-5 Torr, backing off at 6.0e-5 Torr. IG1 = 4.80e-6 Torr Tapped up to 30A, 0.45V Waited ~1hr, vacuum stable. IG1 = 8.3e-6 Torr Initiating auto-ramp  Wednesday, May 24, 2017, 09:26 IG1 = 5.5e-5 Torr TGHT = 64A, 0.72V Vacuum currently yo-yo-ing. Changing vacuum limits to attempt to speed up process. Vacuum limit stop at 1.0e-4 Torr, backing off at 5.0e-4 Torr. Once vacuum settles and vacuum starts to drop will adjust limits again accordingly.  Wednesday, May 24, 2017, 11:17 IG1 = 1.2e-4 Torr TGHT = 69A, 0.74V TGHT direct readout = 66A, 0.73V Thermometer attached to TP = 41.0C Room temp = 24.0C Wednesday, May 24, 2017, 13:16  Vacuum going well. Stable yo-yo-ing at current vacuum limit. TP = 41.5C, RT = 23.9C IG1 = 1.2e-4 Torr TGHT = 71A, 0.77V Increasing vacuum limit stop to 2.0e-4 Torr. Thursday, May 25, 2017, 13:03 Vacuum has stabilized. TGHT = 188A, 1.85V IG1 = 2.2e-5 Torr. Adjusting vacuum limits so when 2nd phase starts, vacuum does not spike. Vacuum limit stop at 5.0e-5 Torr, backing off at 1.0e-4 Torr.    Friday, May 26, 2017, 13:40 Everything tripped off this morning at around 4:30am This was not due to the vacuum spiking as one would expect. No power bumps according to  ISAC controls. Looking back on elogs  [see elog i.d. 145] evap1 had also tripped off during the last round of carbonizing UO2, however last time everything tripped off ~60A. For last trip off the water valve remained open and on. This time  WV1 showed yellow in the TGHT epics box, off under WV epics box, but black [open] in the WV epics box diagram [see screenshot for better understanding]. Water valves are closed - confirmed in person - water wheels not turning. Trip-off occured ~275A. Vacuum was stable at trip-off point; IG1 ~6e-6 Torr  Reason: currently unknown.        Friday, May 26, 2017, 15:43 Starting pumping down again this afternoon while trying to understand trip-off - no progress on that end. IG1 = 4.9e-6 Torr Tapped up to 40A, 0.24V Vacuum spiked to 2e-5 Torr Backed off to 35A, 0.20V Showing lower voltage output than the last round that had tripped off...but ramping is so early on/ low current, hard to tell... Vacuum stable. IG1 = 5.4e-6 Torr Target boat will be ramped up to 275A [trip-off point] at the rate of 0.1A/min. Vacuum limit stop at 5.0e-5 Torr, backing off at 6.0e-5 Torr.   TP = 37.9C, RT = 25.2C    Monday, May 29, 2017, 08:21 Initially it looks like not enough time had been allowed for the vacuum to settle before initiating the auto-ramp resulting in the vacuum spiking and tripping off the system. A closer look shows that is not the case. Note: the vacuum limits were set to stop at 5.0e-5 Torr, backing off at 6.0e-5 Torr.    The TGHT started to back off when the vacuum was ~6e-6 Torr, this is considered a good vacuum and should not have caused the system to initiate backing off yet. Over the course of ~1min, evap1 had backed off all the way down to 0A. At this point the vacuum was now up to ~1.75e-5 Torr and still rising. ~34min after the TGHT had reached 0A, the vacuum eventually reached 8e-4 Torr and tripped off the evaporator. See photos attached.

 Tuesday, May 30, 2017, 07:41

Still unsure as to why evap1 tripped off again.

Put evap1 back under vacuum/ turned turbo pump on and opened isolation valve yesterday afternoon.

Vacuum good this morning...nothing tripped off...

 Tuesday, May 30, 2017, 08:21

IG1 = 2.3e-6 Torr

Tapped up manually to 40A, 0.24V

Waited ~1hr

IG1 = 4.5e-6 Torr

Initiated auto-ramp at 0.2A/min up to a final setpoint of 250A

 Wednesday, May 31, 2017, 09:37

IG1 = 2.4e-6 Torr

TGHT = 250A, 2.57V

Increasing max setpoint to 275A [the trip off point] at a rate of 0.2A/min

Vacuum is currently stable and low; increasing limits to:

Vacuum limit stop at 1.0e-4 Torr, backing off at 5.0e-4 Torr.

 Wednesday, May 31, 2017, 13:39

IG1 = 3.7e-6 Torr

TGHT = 275A, 2.80V

Increasing max setpoint to final setpoint of 520A at a rate of 0.2A/min

Vacuum is currently stable and low; keeping  current limits.

Wednesday, May 31, 2017, 15:57

IG1 = 8.14e-6 Torr

TGHT = 300A, 3.08V

Vacuum stable.

Decreasing ramping rate to 0.1A/min for overnight heating.

turbo pump = 40.5C; room temp = 25.1C

 Thursday, June 01, 2017, 09:00

IG1 = 4.2e-5 Torr

TGHT = 396A, 4.06V

Vacuum stable.

Increasing ramping rate to 0.2A/min.

turbo pump = 41.6C; room temp = 24.3C

 Thursday, June 01, 2017, 13:18

IG1 = 1.25e-4 Torr

TGHT = 439A, 4.48V

Vacuum stable.

Changing vacuum limits.

Vacuum limit stop at 2.0e-4 Torr, backing off at 5.0e-4 Torr.

turbo pump = 42.3C; room temp = 24.6C

 Thursday, June 01, 2017, 15:48

IG1 = 1.95e-4 Torr

TGHT = 467A, 4.81V

Vacuum stable.

Changing vacuum limits and ramping rate for heating overnight.

Decreasing ramping rate to 0.1A/min

Vacuum limit stop at 1.0e-4 Torr, backing off at 5.0e-4 Torr.

turbo pump = 44.1C; room temp = 25.3C

 Friday, June 02, 2017, 07:19

IG1 = 1.26e-4 Torr

TGHT = 473A, 4.77V

Vacuum stable.

Changing vacuum limits and ramping rate.

Increasing ramping rate to 0.2A/min

Vacuum limit stop at 2.0e-4 Torr, backing off at 5.0e-4 Torr.

 Friday, June 02, 2017, 10:18

IG1 = 2.04e-4 Torr

TGHT = 498A, 5.08V

Vacuum stable.

Changing vacuum limits.

Vacuum limit stop at 3.0e-4 Torr, backing off at 5.0e-4 Torr.

Fan has been inserted - pointed at turbo pump, TP temp's have decreased.

tp = 32.1C; rt = 24.7C

 Friday, June 02, 2017, 13:22

IG1 = 2.4e-4 Torr

TGHT = 520A, 5.40V

Vacuum stable and decreasing.

Carbonization process almost complete.

Will remain at max setpoints over the weekend.

TP = 28.2C; RT = 24.5C

 Monday, June 05, 2017, 08:51

IG1 = 1.75e-6 Torr

TGHT = 520A, 5.29V

Carbonization process complete!

Remained at max setpoints over the weekend.

Initiating auto cool at 1.0A/min

 Tuesday, June 06, 2017, 15:56

Vented in Ar and removed today.

Currently in glove box.

 Monday, June 12, 2017, 11:44

Flakes produced: 48.00g