1 ESS Cryogenic regulation loops proposal  Thermal shield  Power Couplers double-wall  CM cool down  Stand by and nominal operation  CM warm up Bertrand Renard – CEA

2 Thermal Shield  Thermal shield pressure: no CV60 open  Thermal shield mass flow rate: no ECCTD only (observation, no regulation)  Thermal shield outlet temperature Measurement: TT65 Redundancy: TT64 Actuator: CV61 Setpoint: 50 K (cool down and nominal)

3 Power Couplers double-wall  PC double-wall pressure: no, CV03 open  PC double-wall outlet temperature: Measurement: TT13 (or TT23…) Redundancy:TT11 (or TT21…) ECCTD only Actuator: CV11 (or CV21…) Setpoint nominal: ~150 K tbc Setpoint cool down: ~TT06 / 2  PC double-wall mass flow rate: only for redundancy Measurement: FT11 (or FT21…) Actuator: CV11 (or CV21…) Redundancy setpoint: define m = f(PC RF power) Cooling-down setpoint: m standby x (300 – TT05)/295

4 Power Coupler heaters  PC outlet heater Measurement: TT15 (or TT25…) Actuator: EH11 (or EH21…) Setpoint: ~285 K tbc Accessible, no redundancy  PC ceramic heater Measurement: TT14 (or TT24…) Actuator: EH12 (or EH22…) Setpoint: ~285 K tbc no redundancy

5 Accelerator cool down to 4.5 K  Cryomodule pressure: CV03 and CV04 open (CV01 open) Measurement: PT03 Actuator: CV02 Setpoint: <1,5 bara no redundancy except for CTL pressure  Cryomodule mass flow rate: no ECCTD only (observation, no regulation)  Cryomodule inlet temperature: no Regulated by the Cryoplant

6 1 CM cool down to 4.5 K  Cryomodule pressure: CV03 and CV06 open Measurement: PT03 Actuator: CV02 Setpoint: <1,5 bara  Cryomodule mass flow rate: no  Cryomodule inlet temperature: no (CV01 open); CV02 opening ramp to reduce thermal gradient

7 4.5 K active standby  Cryomodule bath pressure: CV03 & CV04 open Measurement: PT03 Actuator: CV02 Setpoint: <1,5 bara Accessible, no redundancy  Cryomodule mass flow rate: no ECCTD only (observation, no regulation)  LHe bath level Measurement: LT01 Redundancy: LT02 Actuator: CV01 + CV02 Setpoint: = 25% of Phase Separator

8 Accelerator cool down to 2 K  Cryomodule inlet pressure: no CV03 open  Cryomodule inlet temperature: defined by pressure  Cryomodule bath level CV02 closed ; Measurement: LT01 / LT02 Actuator: CV01 Setpoint: 25% of the Phase separator Actuator: CV04 Setpoint: >10% of the Phase separator This regulation avoids evaporation of the bath. Once 2 K is reached, CV04 opens and CV01 regulates.

9 Nominal operation and 2 K stdby  LHe inlet pressure: no Regulated by the Cryoplant: CV03 open  LHe bath pressure: no Regulated by the Cryoplant: CV04 open  LHe bath temperature: no (imposed by pressure)  LHe level: Measurement: LT01 Redundancy: LT02 Actuator: CV01 Setpoint: = 25% of Phase Separator

10 Accelerator warm up 2 to 4.5 K  Cryomodule pressure: CV03 closed, (CV01 and CV02 open). CV03 closed => no PC cooling CV04 open CTL pressure ramp regulated by the Cryoplant. Measurement: LT01 / LT02 Actuator: Heaters EH30 (and EH40…) Setpoint: 50% of Phase Separator  Cryomodule mass flow rate: no  Cryomodule temperature: no Helium circulation may be used but beware for LHe level rise.

11 CM passive warm up 4.5 to 300 K  Stop Thermal shield cooling  Cryomodule pressure: CV03 closed, (CV01 and CV02 open). CV03 closed => no PC cooling CV06 for 1 CM warm up  Cryomodule temperature Measurement: average of all cold mass T Actuator: Heaters EH30 (and EH40…) to speed up Setpoint: no

12 CM active warm up 4.5 to 300 K  Stop Thermal shield cooling  Cryomodule pressure: CV03 closed, CV01 and CV02 open. CV06 open to He recovery line Cryoplant recovery line sets pressure but overpressure must be avoided Measurement: PT03 Actuator: CV05 Setpoint: <1.2 bara  Cryomodule inlet temperature Measurement: TT05 Redundancy: TT91 Actuator: CV05 Setpoint: = temperature ramp on (TT05+TT06)

13 Accelerator warm up 4.5 to 300 K  Stop Thermal shield cooling  Cryomodule pressure: CV03 closed, CV01 and CV02 open. CV04 open for full machine warm up Cryoplant sets pressure but overpressure must be avoided Measurement: PT03 Actuator: CV05 Setpoint: <1.2 bara  Cryomodule inlet temperature Measurement: TT05 Redundancy: TT91 Actuator: CV05 Setpoint: = temperature ramp on (TT05+TT06)