Internal review of superconductors and magnet laboratories 2nd part: SM 18 & b.163: current status, weak points, possible improvement Cryogenics Vladislav Benda (CERN), Klaus Barth (CERN)

19-May-2009Review of cryo laboratories2 SM 18 operational diagram

19-May-2009Review of cryo laboratories3 SM 18 equipment1/2 ComponentParametersNote Cold box 6 kW Linde m=25 g/s at P=19.3b with LN precoolerPossible upgrade: On line purifier Turbines to be optimized Compressors of the cold box Stal compressors: 2 compressors from 1 to 5 bar 1 compressor from 5 to 20 bar Flow g/s Total power 1.3 MW OK Recovery HP compressors 3 identical 5 stages compressors Burckhardt Flow 3x130 m3/h at 1 bar Power 3x40 kW Pressure 200b Maintenance/replacement (300 KCHF) is required, as they are old and in bad condition. Compressors are not required if a full flow purifier (20b) is installed. HP purifier High level of impurities acceptable (5%) Maximum flow 2x200m3/h Pressure 200b HP purifier is not needed if the full flow purifier is installed. 1.9K Pumping facility 1) WPU1&CCU2&H1 m=18g/s at 1.2 kPa Qheater=32kW at 1 kPa 2) WPU2&H5 m=7.2 g/s at 1.2 kPa Qheater=32 kW at 1 kPa If required CCU3 can be connected to WPU2. OK

19-May-2009Review of cryo laboratories4 SM 18 equipment2/2 ComponentParametersNote Cool down/warm up system CWU1&2, H4,H2, 3 compressors, CWL distrib.line Magnet cooling 120 kW at 80K Magnet warming 30 kW at 320K GHe return warming 200 kW at 300K 3 compressors Kaeser FS 440 Flow of two compressors: 300g/s at 3b, P=10b Third compressor is redundant OK Cryogenic feeder unit CFB 1 pair of 13kA CL, 2pairs of 600A CLs, HV test in GHe at 300K&1b U=3.1kV, GHe/LHe HX 4.5 g/s, Lambda plate for SC cable from 4.5 k to 1.9 K 10 CFBs operational 2 CFBs partially dismantled Cryobox-string LHe at 4.5K at 3b, GHe return, Shield: GHe in at 19b&50K, GHe out at 18b&75K Cryo lines of CB can be connected either to the cryobox or to Grec. For time being the box is connected to DSL test set up. This set up is foreseen to be adopted for FCM test. RF cavity 2 horizontal, ~5 g/s per bench 4 vertical, big consumption during cool down an filling, small consumption during operation Cryostats are not shielded Distribution line has a very high consumption (~12 g/s). The line is not shielded. A new low heat inleak line including 1.9K pumping is required. DSL test set up 1 pair of 600 A CL replaceable for 13 kA CL, HV test at 2 kV, Saturated or supercritical He for experiment Originally designed for DSL test

19-May-2009Review of cryo laboratories5 Magnet test facility in SM 18 Heavy cold mass, frequent cool down/warm up, working at 1.8 K Combined cryogenic line (CCL) GHe pumping LHe GHe Returns Cooling line Warming line Cooling/warming line (CWL) Cryogenic feeder units (CFB) Cooling unit (CWU) & GHe heater GHe LHe Cryogenic line (CL) Very low pressure heater (VLPH) Cold compressor unit (CCU)

19-May-2009Review of cryo laboratories6 GHe/LN pre-cooling system in SM 18 Is it necessary to pre-cool cold masses with GHe/LN system? It is simpler to cool it down directly with LHe! –Consumption of LHe in litres required to cool down 1 kg of stainless steel 1 – 32 from 300K to 4K 0.1 – 1.4 from 80K to 4K –Maximum represent utilization only of a latent heat of LHe –Minimum represent a full enthalpy –Real figures depends on heat exchange during a cool down It is evident that for heavy cold masses frequently cool down the GHe/LN pre-cooling system is more economic.

19-May-2009Review of cryo laboratories7 Proposal of SM 18 cryogenic upgrade SRF cavity – LHe distribution line to be changed –Heat leak to be reduced from ~12g/s to ~2 g/s (shielded line) –1.8 K pumping head to be integrated –Total cost estimation ~ 800 kCHF All other cryogenic lines shall be low consumption, shielded lines. Full flow dryer and full flow precooler/adsorber to be installed –Downtime reduction by avoiding the clogging –The whole system can work permanently at full power (both 1.9 K pumping units). –Cost estimation ~ 800 kCHF (French special contribution?) Upgrade of 6 kW cold box from refrigerator to liquefier –4 turbines to be changed/arranged including pipework –Estimated extra LHe production ~ 4 g/s –Cost estimation ~ 500 kCHF Control system from ABB & PCview32 to UNICOS –Duration: 2 years –Budged required:~250 kCHF –Resources required:1 engineer for 2 years –Implementation by steps Stop for 2-3 weeks

19-May-2009Review of cryo laboratories8 Proposal of the new cavity cryogenic distribution line in SM 18 Design and Technical specification to be done One valve box required per a bench Particularity of the line –Twin valve protection Bench branch lines disconnected while the main line is cold –He guard Protection of sub-atmospheric circuits Protection of twin valves volume –Each valve box includes: One heat exchanger One phase separator One He guard

19-May-2009Review of cryo laboratories9 Proposal of the new full low purifier in SM 18 Full flow precooler/adsorber unit Full flow helium dryer

19-May-2009Review of cryo laboratories10 Number of Tests in SM18 up to 2014

19-May-2009Review of cryo laboratories11 Compatibility with 6 kW 25 g/s) CB LHe production Average consumption needed (in g/s) Considering 6 kW CB current capacity 25 g/s, the requirements cannot be fulfilled at a present condition. Only if the CB is fully upgraded (~30g/s) and the cavity transfer line is changed the requirement can be fulfilled except for Peak of consumption possible: boosting by LHe, GHe to atmosphere or adapting the priorities between the tests. New cavity line and CB upgrade is not expected before nd st nd st nd st nd st nd st nd Cavities (with new cavity line 2 g/s)* Magnets Total Total if existing SRF cavity line (+10 g/s)** * Estimated consumption of the new line~2g/s ** Consumption of the existing line~12 g/s

19-May-2009Review of cryo laboratories12 SM 18 summary Compatibility of LHe required consumption and LHe production –Reduction of LHe consumption New distribution SRF cavity cryogenic distribution line All other cryogenic lines, cryostats and valve boxes to be shielded –Increase of cooling capability 6 kW cold box upgrade –In any case the consumption requirement in 2013 cannot be fulfilled Control system to be transferred to Unicos Typical tests suitable for SM 18 –Heavy cold masses to be pre-cooled by GHe/LN circulation preferable at high pressure –Working temperature 1.8 K

19-May-2009Review of cryo laboratories13 Building 163 operational diagram

19-May-2009Review of cryo laboratories14 Building 163 equipment 1/2 ComponentParametersNote Cold box Linde/Sulzer Cemtec 5g/s with LN precoolingFilter of turbine is clogged. Origin 1980, recuperated 1997 Compressor of the cold box Kaeser FS g/s at 13 b, P=250kW, U=400V Cooling water 7m3/h The same compressor is in b.165 and can be used for the cold box in b. 163 (reciprocity). OK 5x 1.8 K pumps 1x purge pump Leybold Segelec SV 300 Origin 1998 All pumps are identical OK 1.8 K Freska pumping unit 2x primary Alcatel x roots Alcatel RHV 300 P=45 kW 2x400 m3/h 3000 m3/h Very old, no maintainance, leaky. Estimated cost of a new one of the same pumping speed is about 120 kE. Leybold, fully automatic, one primary: SV600 & one roots 3000m3/h.

19-May-2009Review of cryo laboratories15 Building 163 equipment 2/2 ComponentParametersNote HP recuperation compressor in b m3/h, P=180bOK Two other compressors in bad condition. Buffers for pure He 4x 80m3 at 12 b HP buffers: 70 m3 at 150b 6x 80m3 at 12b close to b.180 (BEBC) Big dP (12b), Larger diameter of a connecting pipe is required. Buffers for impure He 18m3 at 150b Dryer and purifier, twin 2x200m3/h P=180b OK Dryer for impure He 400m3/hOK Gasholder 40m3OK

19-May-2009Review of cryo laboratories16 Liquefaction capacity in b.163 Nominal capacity150 l/h Real capacity130 l/h ~5g/s Today capacity 80 l/h –because of turbine filter clogging (charcoal powder?) Change of the filter is foreseen for week 28 –Stop for 3 weeks, Unicos transfer in the same time Cost estimation10 kCHF Required capacity130 l/h Possibility to boost capacity by external source of LHe –Limitation: volume of He buffers Possibility to use BEBC buffers more efficiently. New connecting line of a larger diameter is required. At a peak consumption GHe possibly to atmosphere

19-May-2009Review of cryo laboratories17 Building 163 summary Major part of the equipment is in a good condition Weak point to be treated –1.8 K Freska pumping unit is too old Its replacement is recommended –Cold box Clogging of the filter to be investigated and solved –If more often replacement of the filter is required an access shall be improved. Quite old –Possibility to change it for Block 4 cold box –6 “BEBC” buffers to be use more efficiently

19-May-2009Review of cryo laboratories18 HP recovery Burckhardt compressors in SM 18

19-May-2009Review of cryo laboratories19 1.8K Fresca pumping unit