| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Jim Irby |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| cryopump commissioning/wolfe |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:56:613PM |
| Author: To Be Determined |
| Physop Summary for 960821 This run was supposed to be in support of two MP's: #160 Cryopump Commissioning and #161 Low Triangularity development The run was expected to start late because of the EF4 problem that ended Tuesday's run. However, while the engineers were involved in replacing fuses and devising schemes for instrumenting the fault and (hopefully) avoiding it, there was a vacuum accident that scrubbed the run. The F-side ratiomatic was observed to be inoperable, and when Joe Snipes went into the cell to change filaments he accidentally broke a feedthrough, bringing the torus to atmosphere in a few minutes. EF4 tests were carried out in the afternoon. These were uneventful. New instrumentation had been added to monitor the gate pulses on the rectifiers and crowbars. IN addition, the half of the crowbar in the forward cabinet that was implicated in each of yesterday's events was removed. There seems to be evidence that this section fired without being properly triggered, causing the problems. EF4 was tested under PLC and under hybrid control, with double swings up to 3000A (6000A from the supply) and no faults were observed. Shot 7 included a full TF (5.3T) PLC pulse. Details in the logbook under PHYSICS_OPERATOR. Meanwhile, the ratiomatic was replaced and the machine pumped down. Pump-down was slow probably due to water frozen out on cold surfaces. The pressure was down to 1.e-4 at 17:30, and ECDC in D2 set up for overnight. |
| Session Leader Comments |
| Physics Operator Comments | |||
| Aug 21 1996 08:37:13:050AM | Steve Wolfe | Run Plan for Wed. 960821
MP#160 Cryopump commissioning (1/2 run) MP#161 Low triangularity development (1/2 run) SL Irby, Hutch PO Wolfe Engineering setup: ------------------ No overnight ECDC ECDC in D2 for 2 hours before run Start with power system settings as on 960820004 Gas setup: fill A-side with 20 PSI of D2 fill B-top with 5 PSI of D2 fill B-side-lower with 4 PSI of Ar | |
| Aug 21 1996 08:37:55:350AM | Steve Wolfe | Special Engineering:
-------------------- The EF4 problem which ended the Tuesday run, and proposed solutions, should be reviewed and appropriate action taken prior to starting this run. Since the second half of this run, and runs scheduled for later in the week, will require parallel EF4 operation at relatively high currents, it is essential that the EF4 faults be addressed. This may delay the start of this run by one to two hours. | |
| Aug 21 1996 08:39:14:160AM | Steve Wolfe | Run Plan:
--------- The first half of the run is to be used for commissioning the divertor cryopump. We will start with two fiducial-like baseline shots, based on 960820017, with the LN2 shield cold. The LHe pots will then be filled and we will run 2-4 nominally identical shots, monitoring pressures and gas consumption. Ar will be fired on all shots and the Ar levels determined. JT will orient the McPherson to look at the divertor. After several shots with the cryopump cold, we will close gatevalves and turn off all torus ionization gauges (ITG and the ratiomatics) and allow the pots to warm up, measuring the pressure rise as a measure of the total gas load. Finally a density scan will be performed to try to determine pumping speed as a funciton of divertor pressure, after which the pots will again be dumped into a closed-off machine. | |
| Aug 21 1996 08:39:44:570AM | Steve Wolfe | The second half of the run will be an attempt to develop reduced triangularity
discharges, in support of the JET similarity experiment (MP161) and the h-mode triangularity scan (MP143A). Assuming Yuichi is still attempting to do RF conditioning we will operate with a flattop Bt=5.4T. Initial shape changes will be done at 800kA (standard fiducial level), then once the target equilibrium (delta_l <= 0.4, delta_u <= 0.2?, k=1.65) the current will be raised in steps to approximately 1.2MA (q95=3.1). | |
| Aug 21 1996 08:51:50:210AM | Steve Wolfe | Start from 960820016, a so-so successsful startup from yesterday. It looks
to me like the OH voltage tweaks need to be modified, and there seems to be a negative radial field that should be removed. Also, it is possible that an adjuctment to the Segment 1 RCUR offset is indicated. I'll start from #16, which did work, and tweak from there. 08:45 Load from 960820016 and Load_into_model 08:49 Coldstart -- ok. Frnak predicts start of run at 10:30-11:00 | |
| Aug 21 1996 11:44:55:990AM | Steve Wolfe | The F-side ratiomatic seems to have died overnight. Snipes is changing
filaments before we get started. Disaster! Broke vacuum at the F-port gauge. Machine is up-to-air. We can still do some power tests, but no run today. | |
| Aug 21 1996 03:53:45:640PM | 960821001 | Steve Wolfe | EF4 test (PLC): -1500A, Large difference current due to temperature
imbalance, but basically ok. |
| Aug 21 1996 04:11:52:450PM | 960821002 | Steve Wolfe | EF4 test (PLC): 1400A +direction, balance is better. No faults.
|
| Aug 21 1996 04:24:46:770PM | 960821003 | Steve Wolfe | EF4 test (PLC): Same test again, with terminators on the pierson gate
current monitors. ok. |
| Aug 21 1996 04:39:25:350PM | 960821004 | Steve Wolfe | EF4 test (PLC): No power, test of crowbar instrumentation.
Too quick on the trigger button; try again. |
| Aug 21 1996 04:45:20:050PM | 960821004 | Steve Wolfe | EF4 test (PLC): 6kA(total) EF4 test (+ direction). Looks ok,
got 2923A in each coil. NO crowbar. |
| Aug 21 1996 04:45:35:870PM | 960821005 | Steve Wolfe | shot 5: EF4 test (PLC): 6kA(total) EF4 test (+ direction). Looks ok,
got 2923A in each coil. NO crowbar. |
| Aug 21 1996 04:58:51:970PM | 960821006 | Steve Wolfe | 960821006
Hybrid control: -1000 to +3000 Use only segment 1, disable IP control. Looks fine. |
| Aug 21 1996 05:13:10:350PM | 960821007 | Steve Wolfe | 960821007
TF and EF4 test: Hybrid control on EF4: -1000 to +3000 Change V_EF4 to go to zero after 0.1sec (approx) to get rid of oscillation around crossover. TF under PLC control. NO faults. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 03:49:49:670PM | Test | Ok | ef4 test forward |
| 2 | 04:07:54:540PM | Test | Ok | ef4 reverse |
| 3 | 04:21:34:770PM | Test | Ok | |
| 4 | 04:31:24:760PM | Test | Ok | xbar test no alternator |
| 5 | 04:42:42:930PM | Test | Ok | ef4 6ka reverse bridge |
| 6 | 04:53:57:880PM | Test | Ok | |
| 7 | 05:07:17:130PM | Test | Ok | tf ef4 forward and reverse |