Lambda plates for WP 3 Engineering detailed design

Lambda plates for WP 3: Engineering detailed design Y. Leclercq, S. Spathopoulos*, F. Crisci, J. B Deschamps, S. Donche for WP 3 Engineering Design Review of the Lambda Plate for WP 3 13. 04. 2021

General overview Integration and environment Two lambda plates, one for DFX-IT and one for DFM-D 2 interface located at 89. 5 m and 140 m from IP respectively. Functional requirements § § § Leak tight separation between Cold powering (DFX/DFM) and Magnet sides (IT/D 2) Electrical continuity without influencing electrical performances and quench detection between two separated volumes Electrical insulation to ground and between conductors Withstand Lorentz forces Comply with PED standards where applicable. Engineering design basis Key design features for each LP based on know-how from LHC experience EDMS 2518554 2

Lambda plate design description A. Structural parts § § § Support plate Thermal plate Electrical insulation support flange B. Plug sub-assemblies § λΜ -> 2 x 18 k. A plug + 2 x 2 k. A 4 -in-1 plug λΜ § λΧ λX -> 7 x 18 k. A plug + 3 x 2 k. A 4 -in-1 plug Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 3

Lambda plate design description - Structural parts A. Structural parts § Support plate § § § Material: Main skeleton of the lambda plate Butt welded to HV tubes of DCM and DFX Stainless Steel Thermal plate Material: EPGC 203 (G 11) EN 1. 4429 grade Dimension: Ø 310 mm x 30 mm Thermal plate § § § Support plate Dimension: Ø 293 mm x 30 mm Glued on both sides of support plate Limits heat load exchange between adjacent volumes Electrical insulation support flange § § Compress homogeneously the knife edge of the electrical insulator to the support plate Connected to support plate with screws and elastic washers Electrical insulation support flange Material: Stainless Steel EN 1. 4306 Dimension: Ø 60 mm x 5 mm DCM-IT Lambda plate (λΧ) 4

Lambda plate design description- Plug subassemblies B. 18 k. A plug type 18 k. A SC Cable § 1 x 18 k. A Sc cable (Cu: 87 mm 2 + Nb. Ti: 11. 4 mm 2) § Electrically insulated with Kapton® tape § Sc cable soldered (60 mm) -> leak tightness through core § SC cable + solder part-> Glued to electrical insulator (PEEK) Material: Nb. Ti: 11. 4 mm 2 Cu: 87 mm 2 Dimension: Cu core= Ø 10. 9 mm SC = Ø 13 mm with Eccobond 286 § Increase heat conductive path of adjacent volumes § Reinforce cable + electrical insulator mechanical interface § Additional electrical insulation in case of Kapton tape damage Solder + SC Cable Material: Sn. Pb 60 -40 Cable properties (A. Ballarino, J. Fleiter “Busbar_for_WP 6 a_Inner_triplets”, EDMS 2376444) Thermal insulators glued on both ends § Glue Material: Epoxy Reference: Loctite Ablestik 286 Blue Eccobond 286 Blue 50 ml Twinpac Cable insulation Material: Polyimide (Kapton tape) Thermal insulator Material: ABS F. P Electrical insulator Material: PEEK 5

Lambda plate design description- Plug subassemblies B. 2 k. A 4 -in-1 plug type § Same principle is applied as in 18 k. A plug in most components § 4 x 2 k. A Sc cables (Cu: 20. 7 mm 2 + Nb. Ti: 3. 8 mm 2) instead of 1 Glue Material: Nb. Ti: 3. 8 mm 2 Cu: 20. 7 mm 2 Material: Epoxy Reference: Loctite Ablestik 286 Blue Eccobond 286 Blue 50 ml Twinpac Dimensions: Cu core= Ø 4. 9 mm SC = Ø 7 mm x 18 k. A § 2 k. A SC Cable Solder + SC Cable Material: Sn. Pb 60 -40 Electrical insulator component has 4 individual bores and each Cable properties (A. Ballarino, J. Fleiter “Busbar_for_WP 6 a_Inner_triplets”, EDMS 2376444) one of them intended to a single 2 k. A cable Cable insulation Material: Polyimide (Kapton tape) Thermal insulator Material: ABS F. P Electrical insulator Material: PEEK 6

Electrical Insulation design description § Each Sc cable is Kapton insulated until 5 mm within electrical insulator § Non Kapton-insulated cable covered by continuous layer of Eccobond and overlaps cable insulation for 40 mm § SECTION CUT Insulation layout 18 k. A plug For the 2 k. A 4 -in-1 plug, each cable has its own bore inside the electrical insulator 2 k. A 4 -in-1 plug Electrical insulation layout Section view of the plug assembly prototype Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 7

Mechanical design Stainless steel envelope § § The lambda plate envelope shall comply with PED 2014 -68 -EU FEA calculations to confirm compliancy of the structural design with requirements of the Annex B and C of the EN 13445 -3 harmonized standard Total deformation during pressure test Gross plastic deformation during pressure test (as defined in EN 13445 -5 Annex B) Polymer parts FEA calculations of PEEK parts at ambient temperature reveals the low level of stress (< 20 MPa equivalent Von Mises stress << Tensile strength at 80 MPa) in the Electrical Insulator for the worst-case scenario. Testing at cryogenic temperature in progress, see qualification presentation Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 8

Thermal performance § § § FEA thermal calculations to evaluate LP thermal behavior and contribution to superfluid volume heat loads Two studies implemented considering or not temperature gradient in saturated helium volume Conservative heat load for λX estimated below 12 W which is compliant with allowable budget of 15 W Temperature distribution in λX (T gradient in liquid), EDMS 2508715 Heat loads to Superfluid volume Individual 18 k. A plug (RRR 100) Individual 2 k. A 4 -in-1 plug (RRR 100) Lambda plate + DFX/DCM insulation plate Lambda plate + DFX insulation disk (assuming no efficiency of Insulation Plate on superfluid side) Full lambda plate assembly (RRR 100) Assumption : Temperature Gradient in saturated liquid NO YES 1. 1 W 0. 34 W 1. 1 W 0. 35 W 0. 6 W 0. 1 W 0. 8 W 0. 1 W 11. 6 W 3. 4 W Heat loads contribution to superfluid for the various Lambda Plate parts, EDMS 2508715 Temperature distribution in λX (no T gradient in liquid), EDMS 2508715 Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 9

Leak tightness design features Through cable § Leak tightness through cable is obtained by soldering (filling gaps with Sn. Pb) Soldered cable -> Electrical insulator § Leak tight interfaces Leak tightness is performed with Eccobond 286 glue Electrical insulator -> Support plate § Leak tightness is ensured with the machined knife edge of electrical insulator part Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 10

Risk Analysis § A risk assessment of the plug is presented in § 4. 1. 6 of the WP 6 a failure mode analysis § The scenario is a rupture of the Glue-PEEK interface leading to a mass flow of 0. 4 kg/s to the DFX volume. § The DFX safety relief devices are sized considering this scenario (PDFX<PS=3. 5 bara) § DFX-DSHX-DFHX : Safety relief devices calculations EDMS 2365987 Tests at 77 K are performed on the plug applying 1 k. N axial load to the cable. Visual inspections and leak test have not revealed any visible defects nor leak (tested to 10 -10 mbar. l. s-1) Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 11

Maintenance approach for λX § In the unlikely case of a developed leak at the plug level or the deterioration of one superconducting cable, the replacement of one plug or the entire Lambda Plate may be required. § Due to the sequence of operations and quality controls linked to the replacement of a Lambda Plate Due to the level of activation in the area where th DCM is installed § § The strategy in case the Lambda Plate needs to be replaced is to install the spare DCM (or repair the DCM at the surface). Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 12

Conclusion § The detailed design of the Lambda Plate is developed to fulfil the functional requirements § Next presentation presents the qualification of the design with respect to specifications § The design with respect to pressure equipment is performed according to standards for metallic parts and based on calculations for materials not covered by standards § The potential degradation of plugs is assessed and safety relief devices sized to contain the unlikely event § Due to the space restriction, the duration of the operations, replacing a plug/cable in the tunnel requires a repair at the surface Lambda plates for WP 3: Engineering detailed design– 13. 04. 2021 13