Impact of process parameters and design options on heat leaks of straight cryogenic distribution lines

The Future Circular Collider (FCC) accelerator will require a helium distribution system that will exceed the presently exploited transfer lines by almost 1 order of magnitude. The helium transfer line will contain five process pipes protected against heat leaks by a common thermal shield. The design pressure of the FCC process pipe with supercritical helium will be equal to 5.0 MPa, significantly exceeding the 2.0 MPa value in the present, state-of–art transfer lines. The increase of the design pressure requires construction changes to be introduced to the support system, the vacuum barriers and the compensation bellows. This will influence heat flows to the helium. The paper analyses the impact of the increased design pressure on the heat flow. The paper also offers a discussion of the design modifications to the compensation system, including the replacement of stainless steel with Invar—aimed at mitigating the pressure increase.

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Figure 1

Schematic diagram of the two proposed helium distribution networks for the FCC study [5].

Figure 2

Schematic view of a 50 m section of a cryogenic transfer line based on standard design solutions.

Figure 3

Schematic view of two 12 m modules included in the 50 m section of a cryogenic transfer line.

Figure 4

Schematic diagram of proper supports for the compensation bellows [6].

Figure 5

Comparison of the properties of stainless steel 304L and Invar^® [9].

Figure 6

Schematic diagram of a 50 m straight section of a cryogenic distribution line with Invar^® process pipes.