ESS CRYOMODULE FOR ELLIPTICAL CAVITIES

Transcription

1 ESS CRYOMODULE FOR ELLIPTICAL CAVITIES BREAKDOWN OF CRYOGENIC COOLING CIRCUITS Auteur OLIVIER Gilles Date : 03/03/2015 Date : 03/03/2015 Vérifié par BOSLAND Pierre Signature Signature VERSIONS Date 03/03/2015 V1 Document creation 02/10/2015 V2 Update with Ps=1.04bar Version & modifications EDMS I / 10

2 1 PRESENTATION OF THE ESS PROJECT The European Spallation Source (ESS) is a multi-disciplinary research center based on the world s most powerful neutron source. After completion, it will improve visualization techniques and enable new opportunities for researchers in the fields of life sciences, energy and environmental technology. It is under design and construction in Lund, Sweden. The linear proton accelerator is composed of an ion source, different stages of bunching and pre acceleration, 3 superconducting sections and a heavy metal target. The superconducting part of the linac is composed of 3 strings of 26 spoke cavities (β=0.5), 36 medium (0.67) and 84 high β (0.86) elliptical cavities. The cavity string is cooled at 2K in a helium bath. A thermal shield cooled at 50K limits the heat losses of the cold mass. 2 PRESENTATION OF THE CRYOMODULE 2.1 Cavities Each cavity is composed of 5 (high beta) or 6 (medium beta) cells made of superconducting niobium at low temperature. A radiofrequency power is supplied by means of a coupler and its antenna. This RF wave creates an accelerating electric field for the beam inside each cell. The holding at low temperature is carried out by immersion in a helium bath contained in a titanium tank. Nozzle for diphasic pipe Cavity Coupler Nozzle for cooling down Helium tank EDMS I / 10

3 2.2 Cryomodule As the superconducting cavities are cooled at 2K, the cryomodule is used to insulate the cavity string from the outside and limit the calorie intake in addition of its holding and positioning functions. The convection losses are limited by the insulating vacuum and the radiations ones by the intermediate shield cooled at 50K and surrounded by a multi-layers insulation wrapping. 3 PRESENTATION OF CRYOGENIC LINES 3.1 General diagram EDMS I / 10

4 3.2 Low pressure line (cavities cooling) This line is a diphasic circuit (liquid/vapour) containing helium at 2K and 30mbar. The large diameter of the this pumping line limits the pressure drop during pumping and allows the fast discharge to the bursting disks in case of accident. The safety is ensured by rupture disks and 2 relief valves upstream. The filling line allows the bath level complement to compensate the evaporation. 3.3 Cooling down line This circuit allows the cooling down of the cavity string from ambient temperature down to 4.5K. The maximum pressure is that of the supply line: 3 bar. EDMS I / 10

5 3.4 Couplers cooling line The couplers ensure the interface between the external RF wave guides and the cavity, and its RF coupling by means of the antenna. The cooling of this component at 4.5K reduces the conduction and radiation heat losses of the cavity on this area. The maximum pressure is that of the supply line: 3 bar. The safety is ensured by a relief valve calibrated at 2.3bar and located outside the cryomodule in the valve box. 3.5 Thermal shield cooling line The thermal shield limits the radiation calorie intake on the cavities. It is cooled at 40/50K and the maximum pressure is that of the supply line: 19.5bar. The safety is ensured by a relief valve calibrated at 21bar and located outside the cryomodule in the valve box. EDMS I / 10

6 4 BREAKDOWN OF THE LOW PRESSURE CIRCUIT 4.1 Cavities and pumping necks Ps TS (K) L C1/2/3/4 - He tank (V=48l for HM, 46l for MB) V L/G x x 48 Ti / Nb / NbTi C5/6/7/8 - He tank neck P L/G ,48 Titanium Phase L: Liquid Phase G: Gas Ti : Titanium Nb : Niobium NbTi : Niobium-Titanium Type V : Vessel Type P : Pipe Type B : Bellows EDMS I / 10

7 4.2 Diphasic line Ps TS (K) L LP01/02/03 LP31/32/33 - Bursting disk pipe P G Stainless steel LP04/06/28/30 - Bellows 105x132 B G ,63 Stainless steel LP05/29 - Straight section P G ,46 Stainless steel LP07/08/09/10 LP24/25/26/27 - Straight section P G Stainless steel LP11 - Straight section (cavity 1 nozzle) P L/G ,92 Titanium LP12/14/16/18/20/22 - Bellows 105x132 B L/G , ,88 Titanium LP13/17/21 - Straight section P L/G ,85 Titanium LP15/19 - Straight section (Cavity 2/3 nozzle) P L/G ,91 Titanium LP23 - Straight section (Cavity 4 nozzle) P L/G ,04 Titanium 4.3 Jumper circuit Ps TS (K) L JLP01 - Diphasic pipe connection P G ,61 Titanium JLP02/03/04 - Exchanger SD G Stainless steel JLP05/06 Jumper elbow P G ,85 Stainless steel Type SD : Specific Device (under pressure) EDMS I / 10

8 5 BREAKDOWN OF THE HIGH PRESSURE CIRCUIT 5.1 Jumper circuit Pressure design TS (K) L J5K01 - Manifold V or P L ,03 Stainless steel J5K02 - Manifold to bellows P L ,03 Stainless steel j5k03 - Bellows 8x13 B L ,01 Stainless steel J5K04 - Bellows to exchanger P L ,03 Stainless steel J5K05 - Exchanger SD L x x 0,17 Stainless steel J5K06 - Manifold to jumper elbow P L ,08 Stainless steel 5.2 Cavity filling circuit Pressure design TS (K) L CC01/02 - Exchanger outlet & straight section P L ,24 Stainless steel CC03 - Bellows 8x13 B L ,05 Stainless steel CC04/05 - Straight section & CV90 valve inlet P L ,26 Stainless steel CC06 - CV90 valve outlet to diphasic pipe P L/G ,08 Stainless steel EDMS I / 10

9 5.3 Cooling down circuit Pressure design TS (K) L CD01 - Manifold to CV03 valve P L ,05 Stainless steel CD02 - CV03 valve to bellows P L/G ,01 Stainless steel CD03/05/07/09/11 - Bellows 8x13 B L/G ,01 Stainless steel CD04 Bellows to bellows P L/G ,06 Stainless steel CD06/08 - Bellows to bellows P L/G ,11 Stainless steel CD10 - Bellows to bellows P L/G ,09 Stainless steel CD12 - Bellows to level gauge P L/G ,04 Stainless steel CD13 - Level gauge tank V? L/G ,73 Stainless steel CD14 - Level gauge tank to diphasic pipe P L/G ,02 Stainless steel CD15/16/17/18 - Cavity inlet P L/G ,03 Stainless steel 5.4 Coupler cooling circuit Pressure design TS (K) L CP01 - Manifold outlet P G ,03 Stainless steel CP02/04/06/08 - Bellows 8x13 B G ,01 Stainless steel CP03 - Bellows to bellows P G ,08 Stainless steel CP05/07 - Bellows to bellows P G ,11 Stainless steel CP09 - Bellows to flexible hose P G ,15 Stainless steel CP10 - Flexible hose 8x13 to relief valve B G ,06 Stainless steel CP11/12/13/14 - Coupler inlet P G ,01 Stainless steel CP15/16/17/18 Coupler outlet (bellows 16x22) B G ,15 Stainless steel EDMS I / 10

10 6 THERMAL SHIELD Pressure design TS (K) L JTS01 - Inlet P G ,12 Stainless steel JTS02 - Outlet P G ,10 Stainless steel TS01 - Connector to bi-metallic transition P G ,03 Stainless steel TS02/08/14/20 - Bellows 8x13 B G ,01 Stainless steel TS03 - Bellows to BM transition P G ,01 Stainless steel TS04 - BM transition to extruded pipe P G ,02 Aluminium TS05/11/17/23 - Extruded pipe P G ,63 Aluminium TS06/10 - Extruded pipe to BM transition P G ,04 Aluminium TS07/09 - BM transition to bellows P G ,03 Stainless steel TS12 - Extruded pipe to BM transition P G ,04 Aluminium TS13 - BM transition to bellows P G ,01 Stainless steel TS15 - Bellows to BM transition P G ,01 Stainless steel TS16 - BM transition to extruded pipe P G ,03 Aluminium TS18/22 - Extruded pipe to BM transition P G ,02 Aluminium TS19/21 - BM transition to bellows P G ,01 Stainless steel TS24 - Extruded pipe to BM transition P G ,01 Aluminium TS25 - BM transition to connector P G ,02 Stainless steel EDMS I / 10