nMPP meeting on Procedures

Tuesday 7 Apr 2009, 09:00 → 12:00 Europe/Zurich

30/7-012 (CERN)

Slides

• MPP_2009-04-07.pdf
• MPP_2009-04-07.ppt
• nMPP_070409.pdf
• nMPP_070409.ppt
• nMPP-meeting-C.S.-7.4.2009.pdf
• nMPP-meeting-C.S.-7.4.2009.ppt
• Report_to_nMPP_7_April_2009.pdf
• Report_to_nMPP_7_April_2009.pptx
• Res_meas_interconnect.pdf
• Res_meas_interconnect.ppt

MINUTES:

ARJAN Presentation on RB Powering Circuit Procedure:

The procedure was revised following the input of last nMPP meetings. The following tests were added/modified:

-          PQC (new test): to perform Quench Detection Calibration.

-          It is proposed to SUBSTITUTE the “Heaters induced quench test” before the PLI-2 with a “Fast power abort”.

-          PLI-2: the test shows a long ramp-up and ramp-down due to presence of a lot of plateau. It will be the first test-step providing information on circuit resistance.

-          PLI-S (new test): it is composed of 9 plateaus of 10 min each. The “OK to go on” with this test will be done following analysis of PLI-2 test results.

-          PLI-3: the first test-step with calorimetric measurement.

-          PNO: also with calorimetric check performed. Reminded as the 2009 Nominal current will be 8600 A (for a 5 TeV run).

-          The aim of the last test” Heater induced quench” is to eventually test the performance of nQPS in case of symmetric quenches. A wide discussion followed: Rudiger object that the probability to get a symmetric quench is too low compare to the fact of stressing the magnet by a provoked quench. Arjan seems to justify these 16 in total provoked quench compared to the hundred that the machine will experience anyway. Andrzej propose to move this test to the PGC where conditions are realistic and more information can be obtained. ACTION: PGC editors.

-          Andrzej comment: the possibility to have a software “RED BUTTON” to stop powering test ongoing should be evaluated and investigated. ACTION: Markus Zerlauth

-          Sandrine comment: is it safe to have a calorimetric measurement where the valves are blocked ongoing during a PNO (and PLI-3)test? Will be all the systems (magnets, cryoplants and lines) in a safe condition if one or multiple quenches happen? This point should be confirmed. ACTION: TE-CRG.

ARJAN Presentation on RQ Powering Circuit Procedure:

Very similar to RB.

-          RQD and RQF are powered separately up to PLI-2

-          No “Heaters induce quench” test at 7000 A

-          A unipolar powering failure test must be always done as the last test (to be remembered in case we decide to stop the HWC at a lowered current level). It is proposed to add it as in the cse of the dipoles at lower current.

 

NURIA Presentation on IPQs Powering Circuit Procedure:

GENERAL Powering Procedure:

-          Respect to previous version only one test is proposed to be changed: PNO.C3 PA where the ramp-up is stepped to do electrical measurements on the bus-bars. ALL 3 leads will have a plateau at each steps of the test.

-          BEFORE this test an access to the Tunnel is necessary to set the electronic. All the tests in a DS could be done in one go before another access to remove the equipment. Two sets are available to perform this test in two DS

SPECIFIC to 2009 POWERING:

-          Proposal to drop test PLI2.f3 was rejected (Knud says he need the test).

-          Proposal to drop test PNO.C4 and add the long plateau (1 hour; for current leads check) to PNO.C3PA for 2009 and general procedure was finally rejected: saving in time (just the ramps) is minor compare to test duration and in this way we will avoid to “overload of meanings” the PNO.C3PA test.

-          ACTION HUGUES: to be check if we still need PLI1.C3 and PLI2.E1

-          Amalia asked and Antonio P. confirmed that changes in the cryo valves in the DFBs have and will only concern liquid level setting and not cooling regulations setting.

-          Test-step “Quench_B1” and “Quench_B2” in PIC2 step will be renamed: “Heaters firing_B1” and “Heaters firing_B2” since names are misleading.

-          For IPQs circuits, NOMINAL current setting will be based on values provided by colleagues of BE: they will supply the list of currents for all circuits for 5 TeV powering.

-          A logistic question arises: what we need of nQPS system operational in order to start the IPQ powering tests? ACTION: Knud

-          TE-CRG shall define the support and responsibility (signatures) for calorimetric test during HWC ACTION: TE-CRG.

S.3-4 SPLICE checks at interconnection activities:

ARJAN presented the calculation of splice/stabilization behavior with varying parameters like: gap at Cu interconnection; %age of SnAg soldering presence in the splice; part of cable/stabilizer not in thermal contact. The simulation takes into account the real configuration of the measurements done in the Tunnel with V and I contact pin at 5 mm of distance and at 5 mm from the Cu pieces joint. “Risk areas” for the RB and RQ case are defined (where resistances are respectively > 11.8 and 19.4 µΩ for dipole and quadrupole splices).

GIORGIO presented the statistic for the first measurements done in the Tunnel. Distribution of values seems very consistent with numbers evaluated by Arjan; for MB one case shows an higher resistance (QBBI.B25R3.M3) ; for RB, 3 cases of higher resistance on M1/M2 were measured on Q29 and Q32 interconnections.

CHRISTIAN: he showed the full chain of QC steps put in place on the interconnection inspection in the Tunnel and inform as the US measurements on these NC have not shown any defect. He presented also the γ-rays results of the high resistance splice shot this night, where is clearly visible a lack of SnAg solder in the BB part of the interconnection (the splices itself seems OK).

After a wide discussion it was decided to redo this afternoon the electrical measurement on the dipole suspected NC splice, trying to improve the measurement with a better (more real) injection of the current in the interconnection and try to identify which part of the interconnection may be the cause of the higher resistance. It is also proposed from tomorrow to make similar measurement in the Sector 5-6 where some interconnections are accessible.

Other action with heavier impact on the planning (ex. redo the interconnection completely) are in standby until the results of the new measurements.

STATUS OF NCs in CONNECTION CRYOSTATS on BB SUPPORTING SYSTEM:

VITTORIO: showed an extract of the presentation that he will do this afternoon at the TE Group Leader Meeting.

The real situation of the BB support (in some case out of the nominal 1000 mm inter-supports distance up to ~ 1800 mm) was simulated with FEM and it is confirmed that the BB stabilizer will be plastically deformed (+/- depending by the cases) but, after a certain stroke, they will be for sure be strongly supported by the SS tubes.

The maximum acceptable inter-support distance was assessed for the 5TeV- Nominal – Ultimate current cases. They result respectively in 1550 – 1330 – 1300 mm.

Jean Philippe comment about the reparation done in the case of the .L6 connection cryostat where a NOMEX pipe was slide inside the SS tube all along the full length. On a moke-up a fatigue test up to 12000 cycles was performed showing no damages on the BB insulation. He also comments that, following these last analysis and calculation, only one case of dipole BB (M3) NC will need to be repaired. The other observed NCs seem inside the new tolerance on inter-support distance now estimated.