1. Interface issues on Super-FRS magnets test at CERN
Meeting for Super-FRS magnets test at CERN ( )
Interface issues on Super-FRS magnets test at CERN
Yu Xiang
CrYogenic Department in Common System (CSCY) GSI, Darmstadt

2. Meeting for Super-FRS magnets test at CERN (01.10.2014)
Revised pressure levels and SRV/RD set levels for the pressurized magnet helium vessel according to European Standards EN :2002 (E);
Sizing of the SRV/RD for long multiplet according to European Standards EN :2002 (E) and EN ISO ;
Stress analysis to check fix and sliding points at magnet and cryo-interface;
Pressure rising in helium vessel due to electro-magnetic energy dissipation.

3. Revised pressure levels and SRV/RD set levels (EN 13458-2:2002)
Courtesy to Luigi Serio
DP > 1 bar (rupture disk)

4. Set pressures for safety devices on liquid helium vessel in multiplets and dipoles of Super-FRS
26.3 bar [=1.25 * (20+1)]
DP = 1.1 bar (26.3 – 25.2) > 1 bar
= 25.2 bar
= 22.8 bar
Set pressure of rapture disk: 24 bar
DP = 4.0 bar (= 24 – 20) > 3.0 bar (= 0.15 * 20 bar)
MAAP = 22 bar
= 20.6 bar
= 19.4 bar
Set pressure of safety valve: MASP = 20 bar
MAWP = 20 bar
~ 94
(LESER)
: 18.8 bar (= 0.94 * 20 bar)
(Courtesy to LESER)
: 18 bar (= 0.9 * 20 bar)
MWP = 17.9 bar (=19.4 – 1.5)
(Courtesy to Luigi Serio)

5. Sizing the RD and the SRV for long multiplet under Insulation Vacuum Loss to Air (EN :2002, EN ISO )
Set pressure for rapture disk
Set pressure for safety valve
Minumum size for rapture disk
Minumum size for safety valve
Courtesy of Ruggero Pengo

6. Analysis of total stored energy deposition in helium by simultaneous quench of all magnets in long multiplet
Information of current damping and quench energy Courtesy by E. Floch and P. Szwangruber

7. Sizing the SRV and the RD under combination of insulation vacuum loss to air and worst case quench for long multiplet
0.76 W/cm²
= 0.6 W/cm²
(loss vacuum)
W/cm²
(quench
equivalent,
64 kW / 40 m²)
Set pressure for rapture disk
Set pressure for safety valve
Courtesy of Ruggero Pengo
Minimum size for safety valve under worst quench
Minimum size for
rapture disk under loss
vacuum and worst quench

8. Safety valve from LESER

9. SRV and RD on long multiplet cryostat

10. Interface for cryogenic headers and vacuum flange
Welding flange for process headers : solution from CERN (?)
Vacuum flange : ISO flange from CERN (?)

11. Boundary conditions for Stress analysis on 4
Boundary conditions for Stress analysis on 4.5 K return header at interface under 26.3 bars in pressure test
Spring rate: ~ 200 𝑁/𝑚𝑚
DN 80 (88.9 mm x 3.2 mm)
DN 65 (76.1 mm x 2.9 mm)
2500 mm
Under pressure test conditions,
Forces_DN 65 header / Forces _DN 25 header : ~ 6
3300 mm
Spring rate: ~ 170 𝑁/𝑚𝑚

12. Stress analysis of 4. 5 K return header assembly at interface under 26
Stress analysis of 4.5 K return header assembly at interface under 26.3 bars in pressure test
Safety factor of overall assembly > 1.3
Total deformation at cold mass side: < 0.3 mm
Total deformation at cryo-feedbox side: 3.3 mm
Maximum Von Mises Stress : 319 Mpa !

13. Forces on 4. 5 K return header at interface under 26
Forces on 4.5 K return header at interface under 26.3 bars in pressure test
Force on the cylindrical support : N
Force on the cold mass side: ~ 18 N (force free)
Force on the cryo-feedbox side: ~ 85 N (force free)

14. Stress analysis of 4. 5 K return header assembly at interface 4
Stress analysis of 4.5 K return header assembly at interface 4.5 K operation conditions
To be done:
at pressure 18 bar and 100 K during cooldown;
at pressure 20 bar and 4.5 K due to worst-case quench;
Temperature profile at 4.5 K operation condition
Heat conduction:
7.1 W at 80 K
Heat conduction: 0.4 W at 4.5 K
Total deformation at cold mass side: ~ 1.2 mm
Total forces at cold mass side: ~ 238 N
Maximum Von Mises Stress : 77 Mpa
Safety factor of overall assembly > 3.3
Total deformation (piping shrink) at cryo-feedbox side: 7.6 mm
Total forces at cryo-feedbox side: ~ 295 N (deformation-Y: ~ 1.8 mm)

15. Pressure rising in helium vessel of long multiplet due to electro-magnetic energy dissipation when the long quadrupole quenches.
Science & engineering for cryogenic safety. Philippe Lebrun. European Graduate Course in Cryogenics, Helium Week, WUT & CERN 30 August –3 September 2010
Quench of Long Quadrupole under quench protection
Energy stored at 1.1*In -> 1.29 MJ : P_Helium = 12 bars (+/- 1.0 bar)  
Energy dissipated within coils when Rd=1.4 Ohm -> 77% out of 1.29 MJ = 1.0 MJ : P_Helium = 10 bars (+/- 1.0 bar)
Energy dissipated within coils when Rd=2.1 Ohm -> 66% out of 1.29 MJ = 0.85 MJ : P_Helium = 8 bars (+/- 1.0 bar)  
Energy dissipated within coils when Rd=2.8 Ohm -> 57% out of 1.29 MJ = 0.74 MJ : P_Helium = 7 bars (+/- 1.0 bar)  
Energy dissipated within coils when Rd=4    Ohm -> 44% out of 1.29 MJ = 0.57 MJ : P_Helium = 5 bars (+/- 1.0 bar)

16. Pressure rising in helium vessel of dipole due to electro-magnetic energy dissipation when the dipole quenches.
Quench of Dipole under quench protection
Energy stored at 1.1*In -> 452 kJ:  P_Helium > 20 bars Energy dissipated within the coil when Rd=1.4 Ohm -> 35% out of 452 kJ = kJ : P_Helium > 20 bars
Energy dissipated within the coil when Rd=2.1 Ohm -> 21% out of 452 kJ = 95.0 kJ : P_Helium > 20 bars
Energy dissipated within the coil when Rd=2.8 Ohm -> 14% out of 452 kJ = 63.0 kJ :
for CASE B-1 of CEA dipole, P_Helium = 23 bars (+/- 1.0 bar)
for CASE B-2 of CEA dipole, P_Helium = 17 bars (+/- 1.0 bar)
for CASE B-3 of CEA dipole, P_Helium = 13 bars (+/- 1.0 bar)

17. Thank you for your attention!

18. European Standards (DIN/BS EN 13458)
The sizes for insulation vacuum relief seems too small according to EN :2002
Minimum inner diameter, 25 mm (510 mm² =0.34 mm²/litre x 1500 litres)
Maximum inner diameter, 80 mm (5000 mm²)

19. > 300 mm Meeting for Super-FRS magnet test at CERN (14.11.2013)
One example: Insulation vacuum relief device on cryomodule (~ 1 m diameter and ~12 m long) of XFEL at DESY (picture taken on 16-May-2013)
> 300 mm
Rough estimation of vacuum vessel volume: 9.5 m³ [=12 m*PI*(1 m) ²/4]
Estimation of minimum diameter of vacuum jacket relief device:
64 mm (3243 mm² = mm²/kg x 9.5 m³ x 1000 kg/m³)
> 300 mm

20. Part 3: Determination of required discharge — Capacity and sizing
Cryogenic vessels —Safety devices for protection against excessive pressure
Part 3: Determination of required discharge — Capacity and sizing
6 kW/m typical value from W. Lehman and G. Zahn, 1978
For heat flux due to air condensation on the helium vessel outer surface which is covered with 10 layers MLI Superinsulation
Maximum heat input WS on the helium vessel of short multiplet: 6 kW/m² x 16 m² = 96 kW
Maximum heat input WL on the helium vessel of long multiplet: 6 kW/m² x 40 m² = 240 kW !

21. Part 3: Determination of required discharge — Capacity and sizing
Cryogenic vessels —Safety devices for protection against excessive pressure
Part 3: Determination of required discharge — Capacity and sizing
B. Petersen, MKS, DESY, Tutorial for SRF2007

22. Meeting for Super-FRS magnet test at CERN (14.11.2013)
Courtesy to Luigi Serio,
“Design pressure and pipes sizing of the ITER cryoplant, distribution system and cryolines -ITER_D_2YN5B5 “