Internal review of IR2 LEP cryostats (WP11/WP5) Close out session Diego Perini, Rob Van Weelderen, Jaime Perez Espinos, Jean-Philippe Tock https://indico.cern.ch/event/630930/overview

Are the design and the specifications for procurement at the level of maturity appropriate to start the production? Have all the relevant constraints, e.g. thermo-mechanical, electrical, integration and safety related been identified and taken into consideration in the design? Are the interfaces with neighboring elements well defined and documented? Is the procurement strategy appropriate given the time constraints of the HL-LHC project? Is the assembly procedure well defined and the plans for the assembly facilities, tooling, and personnel, appropriate and compatible with the other activities? Are the quality control plan and the relating tests adequate? Is the proposed schedule realistic?

Connection cryostat LEP(R/L)A LEP(R/L)B As we are doing with the 11T, we replace the existing cryo-assembly with 3 independenly installed units. Each unit is aligned independently. The collimator is installed after the bypass cryostat is in place. From Delio’s presentation

General good quality of the presentations, well prepared. In the large majority of the cases the design foresees ‘standard’ or already tested solutions. Therefore the project looks under control. We spotted a few points that needs some further thinking / consolidation

Q1 Are the design and the specifications for procurement at the level of maturity appropriate to start the production? Yes We assume the use of the specifications of the already existing objects.

Q2. Have all the relevant constraints, e. g Q2 Have all the relevant constraints, e.g. thermo-mechanical, electrical, integration and safety related been identified and taken into consideration in the design? Almost yes with a few points to be checked Connection to line M must have high hydraulic impedance. To be checked. Tolerances are very tight (golden or silver level?). Tuning systems are accessible only during the assembly. Transport issues (vibrations, protection of delicate extremities). Punch system to center the beam pipe in the shell. Stability during thermal cycles? Check metallurgical status (cracks). Electrical safety around the extremity connections must be improved (next slide). Torsion and rotation of the bus bars during the assembly and use. Need of one fix point to avoid rotation. The system gives a local hydraulic restriction in the insulation vacuum volume. Safety valves (quantity, position, release pressure) should be checked. (Valid for the 11 T magnet as well).

Electrical insulation should be revisited in view of increasing margin and robustness, especially but not exhaustively in the following areas  : Lyras protection End cover inner surface insulation Insulation of the tubes going through the shuffling modules (beam lines, heat exchanger,…) Sharp edge of nozzles Dipole lyras of the neighbouring dipoles

Q3. Are the interfaces with neighboring elements well defined and Q3 Are the interfaces with neighboring elements well defined and documented? Yes We do not have too much to say. Standard machine configuration.

Q4 Is the procurement strategy appropriate given the time constraints of the HL-LHC project? Today it is reasonable. Tight time for tendering of some components but still ok. In case of problems with one supplier there is not a lot of margin. Project engineers could be very loaded, especially if there will be issues with the procurement of some critical components. The assembly periods are moving targets embedded into the 11T programme. Fine, but one need flexibility in case of shifts and delays. Bus bars. One firm only (Turkey).

Q5 Is the assembly procedure well defined and the plans for the assembly facilities, tooling, and personnel, appropriate and compatible with the other activities? Globally yes. The document we saw is a good starting point defining the assembly sequence. Tools look fine. The number of identified personnel is fine. We can not judge if the required personnel will be available in due time (compatibility with other activities). An industrial contract to provide the necessary personnel for assembly in the beginning of 2018 seems unrealistic

Q6 Are the quality control plan and the relating tests adequate? There is the need of some work to complete the plan. Test plan and acceptance criteria to be defined. Measuring systems and procedures to be defined. Those points were mentioned but not totally explained during the review. The cold test is planned without current in the bus bars. The overhead/possibility to power (some) of the main bus bars during the cold test should be studied. This could give useful information. We noted that a pneumatic test at 1.26 times the design pressure is acceptable for safety.

Q7 Is the proposed schedule realistic? At the moment and within what we know, yes. The assembly periods are moving targets embedded into the 11T programme. Fine, but one need flexibility in case of shifts and delays.