Internal review of IR2 LEP cryostats (WP11/WP5)
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Diego Perini, Rob Van Weelderen, Jaime Perez Espinos, Jean-Philippe Tock
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https://indico.cern.ch/event/630930/overview
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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. thermomechanical, 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
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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
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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.
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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).
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 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
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Q3
Are the interfaces
documented?
with
neighboring
elements
well
defined
and
Yes
 We do not have too much to say. Standard machine configuration.
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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).
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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
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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.
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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.
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