2. A Safety Overview of the HIE-ISOLDE Project
AP.Bernardes, A.Dorsival, S.Giron, D.Phan, J.Vollaire, D.Voulot
ESS Seminar

3. Outline Introduction to ISOLDE and to HIE-ISOLDE
Radioprotection issues
Cryogenic safety issues
General safety issues
Target failures
10/06/2014
ESS Seminar

4. Outline Introduction to ISOLDE and to HIE-ISOLDE
Radioprotection issues
Cryogenic safety issues
General safety issues
Target failures
10/06/2014
ESS Seminar

5. Introduction Proton beam from PSB: 1.4 GeV 2 µA 3e13 protons/pulse
Cycle: 1.2 s
3 kW average power
Instantaneous power: ≈ 1 GW
10/06/2014
ESS Seminar

6. Introduction  Existing Facility
Selectivity
Isolde
Protons 1.4GeV
HRS
GPS
GPS: M/ΔM=2400
HRS: M/ΔM=5000
Acknowledgment E.Siesling
GPS
HRS
10/06/2014
ESS Seminar 6

7. Introduction  Existing Facility
Beam dump
Target
Front- End
ISOLDE is an Isotope Separator On Line facility dedicated to the production of a large variety of radioactive ion beams
Radioctive ions beams Experimental area
By definition we cannot “enclose” 100% the target with a double envelope
Front-end Coupling table
Target
10/06/2014
ESS Seminar 7 7

8. Introduction  HIE ISOLDE project
Increase of protons beam Intensity (HI Design Study)
Protons/pulse
Intensity μA
Energy GeV
Cycles
Power kW*
2.2
1.4
1.2
3.1
1.1014
6.7 2
13.3
50% of pulses from booster
Increase Energy of radioactive ions beams (HE - October 2015)
REX-LINAC – 3MeV/u
Supraconducting LINAC – 10MeV/u 8
10/06/2014
ESS Seminar 8

9. Introduction  HE upgrade
HIE SC Linac
High Energy Beam Transfer lines HEBT
Compressor building 198
Cold Box building 199
HIE-ISOLDE Facility
High Energy upgrade
Upgrade existing post-accelerator 3MeV /u
with HIE SC supraconducting LINAC
Stage 1  5.5 MeV/u
Final stage  10 MeV/u for A/q=4.5 9
10/06/2014
ESS Seminar 9

10. Introduction  HE upgrade
Compressor building 198
Cooling & Ventilation: finished. Tests demineralized water ongoing.
Cryogenic: Piping done. Compressor frame installed

11. Introduction  HE upgrade
Power distribution racks in place.
Air ducts all in place
Cryo: Cold box under refurbishment
Cold Box building 199

12. Introduction  HE upgrade
Stage 1
Acknowledgement S. Maridor
Cryo Module 1: June 2015
Cryo Module 2 installation: Shutdown 2015/16: Jan – March 2016

13. Introduction  HE upgrade
Superconducting LINAC
- 6 cryomodules
- 32 cavities QWRs Quarter Wave Reasonators geometries
MV of total effective acceleration voltage

14. Introduction  HE upgrade
Thermal shield
Vacuum vessel
RF Cavity
- Accelerating gradient 6MV/m
MHz
Niobium-sputtered copper
Helium vessel (150l LHe)
Solenoid
Solenoid

15. Introduction  HE upgrade
Accessible experimental area
3 HEBT (High Energy Beam Transfer) lines
6 magnetic dipoles 45°
24 magnetic quadrupoles

16. HSE Health, Safety and Environment Unit
Introduction  HIE-ISOLDE organisation
45 MCH Budget
1 MCH Budget
HSE Health, Safety and Environment Unit
Progress on Safety is reported at:
HIE-ISOLDE project management
Steering committee
International Advisory Panel
Safety review

17. Outline Introduction to ISOLDE and to HIE-ISOLDE
Radioprotection issues
Cryogenic safety issues
General safety issues
Target failures
10/06/2014
ESS Seminar

18. Radioprotection issues
Radiological risks with the new LINAC
X-ray from cavities
Use of Stable Beam
Nuclear interactions lead to the production of penetrative secondary particles (neutrons & gammas)
Use of RIB Radioactive Ion Beam
Implantation of RIB (“hot-spot” build-up, contamination risk when opening the vacuum chamber for maintenance)
 Minor compare to low Energy part

19.  Definition of X-Ray sources was needed
Radioprotection issues
X-ray from cavities (operation & conditioning)
Strong source of bremsstrahlung X-rays in some operating conditions
Depends on surface state and cleanliness of the cavity
 Definition of X-Ray sources was needed
ORSAY
Acknowledgment S.Giron and J.Vollaire/DGS-RP

20. Radioprotection issues
Measurements (contact):
Normal operation: few mSv/h
RF conditioning: 20 mSv/h
He processing: 350 mSv/h  Used to size LINAC shielding
350 mSv/h
FLUKA simulation:
Rate of electron production due to “field emission”
Acknowledgment S.Giron and J.Vollaire/DGS-RP

21. Radioprotection issues
Acknowledgment S.Giron and J.Vollaire/DGS-RP
300 μSv/h
10 μSv/h
Identification of weak point
Validation of shielding
40-50 μSv/h
Mitigation measures:
- RF cavities in a shielded enclosure (supervised area <3 μSv/h)
No access to the personnel during operation
X-Ray monitoring with RP alarm outside shielding
Access forbidden to the roof
Additional shielding at each extremities

22. Radioprotection issues
Use of Stable Beam
Beam setting done with higher intensity stable beam (before each radioactive beam)
Diagnostic box inserted to the beam may created a local “hot spot”

23. Radioprotection issues
Use of Stable Beam
Nuclear interactions lead to the production of penetrative secondary particles (neutrons & gammas)
He 19.8 MeV/amu
Acknowledgment : J.Vollaire DGS/RP

24. Radioprotection issues
Acknowledgment : D.Voulot BE/OP
FLUKA simulation He2+ 1 ppA 20 MeV/u (J. Vollaire)
L. Moritz, “ISAC II Safety Report”, TRIUMF, 2006
08/04/14
AP.Bernardes EN-STI

25. Radioprotection issues
Maximum intensities for
3 µSv/h at 1 m
maximum energy
Operational table giving maximum intensity allowed on stable beam
Operation engineer in charge of machine responsible to respect the maximum beam intensities
Acknowledgment : D.Voulot BE/OP

26. Outline Introduction to ISOLDE and to HIE-ISOLDE
Radioprotections issues
Cryogenic safety issues
General safety issues
Target failures
10/06/2014
ESS Seminar

27.  Oxygen Deficiency Hazard and potential exposure to cold burns
Cryogenic safety issues
Each cryomodule contains 150l of LHe at 4.5K at 1.3 bara – 900 liters in total – Tunnel 300 m3
Access requested inside tunnel when cryomodules are cold (steady-state)
 Oxygen Deficiency Hazard and potential exposure to cold burns
150 liters LHe
Acknowledgment : Y.Leclercq
10/06/2014
ESS Seminar

28. Pressure relief devices are routed outside the tunnel.
Cryogenic safety issues
Risk assessment
Scenario: Unexpected vacuum break  Release of He through burst disk located on LHe tank
Safety devices on liquid Helium tank will release He outside of the HIE-ISOLDE tunnel
Tunnel roof
Ghe volume
Relief valve
Burst disc
Lhe volume
0. Nominal conditions
1. Vacuum break
Acknowledgment : Y.Leclercq and D.Phan
2. Air in-flow to the VV
3. Heat transfer to cold surfaces
5. P increase & devices opening
Pressure relief devices are routed outside the tunnel.

29. Cryogenic safety issues
Risk assessment
Design 2: Burst disk on insulation vacuum located at the top of cryomodule routed outside tunnel
Design 1: Burst disk on insulation vacuum located at the bottom of cryomodule not routed outside tunnel – Compensatory measures needed
Due to space constraint on the top plate, design 1 was selected and presented at the safety review

30. Cryogenic safety issues
Volumetric
concentration
of O2 [%]
Temperature [K]
Access only on one side and protective screen between burst disk and work place
AP.Bernardes EN-STI 30

31. A change from design 1 to design 2 was requested by the safety review
Cryogenic safety issues
Risk assessment
Scenario: In nominal operation, the cold mass is cooled down to 4.5K and the pressure in the LHe circuit is 1.3bara. The adjustment mechanisms are operated to re-align the superconducting components. This leads to a full rupture of the biggest bellows.
Safety devices on Vacuum vessel tank will release He outside of HIE-ISOLDE tunnel
0. Nominal conditions
Tunnel roof
1. Bellows rupture
A change from design 1 to design 2 was requested by the safety review
2. Pressure increase
3. Relief devices opening
Updated layout: Pressure relief devices are routed outside the tunnel.
Relief pressure valve
Burst disc
Ghe-Lhe volume
Thermal shield
Vacuum vessel
Path of helium gas
Bellows rupture
10/06/2014
ESS Seminar

32. Cryogenic safety issues
Safety pressure device on insulation vacuum routed outside
Safety pressure device on LHe tank routed outside
10/06/2014
ESS Seminar

33. Outline Introduction to ISOLDE and to HIE-ISOLDE
Radioprotections issues
Cryogenic safety issues
General safety issues
Target failures
10/06/2014
ESS Seminar

34. General safety issues
Cern boundary
Distance < 100m from CERN Boundary and offices building
Offices building

35. General safety issues 2 cooling towers External Noise Sources:
2 chillers
Bld. 198
Bld. 170
Air inlet – Building 198
Air inlet – Building 199
Bld. 199

36. General safety issues Internal noise Sources: Ventilation units
2 compressors
Ventilation units

37. Acoustic panels on walls
General safety issues
Acoustic doors
Acoustic treatment for building 198:
Acoustic panels on walls
Roof treated
Acoustic baffle on inlet air for ventilation units
10/06/2014
ESS Seminar

38. General safety issues
- Noise at CERN boundary complying with the legal value
- Noise at the level of windows office under acceptable tolerance
10/06/2014
ESS Seminar

39. General safety issues
Infrastructure and sensitive equipment shall be designed following CERN Seismic Safety rules:
The French territory is divided in five seismic zones from very low seismicity (seismic zone 1) to strong seismicity (seismic zone 5) – EDMS
CERN is classified as seismic zone 3 – Moderate seismic Hazard
10/06/2014
ESS Seminar

40. General safety issues
HIE-ISOLDE tunnel – Concrete blocks piling structure
10/06/2014
ESS Seminar

41. General safety issues
LMGC90 modele
 Minor change on the structure for a seismic type E (few millimeters of move without any impact on the tunnel stability)
Acknowledgment consultant Résonance and E.Perez-Duenas
10/06/2014
ESS Seminar

42. General safety issues
 Study demonstrated that we have a reserve capacity of a factor 2 for the stability of the tunnel in case of seismic event

43. Outline Introduction to ISOLDE and to HIE-ISOLDE
Radioprotections issues
Cryogenic safety issues
General safety issues
Target failures
10/06/2014
ESS Seminar

44. Solid inside container Liquid inside container
Target failures
Solid inside container
– ISO GPS beam –
3.3.E13 protons per pulse
4 bunches per pulse
572 ns in between each bunch
Fragmentation, Spallation, Fission
Liquid inside container
– STAGISO beam –
1.E13 protons per pulse
3 bunches per pulse
16 μs in between each bunch
ISO GPS beam instead of STAGISO on liquid target
Container weld have cracked  release inside vessel of irradiated Pb
10/06/2014
ESS Seminar

45. Target failures
ISOLDE operator in charge choses the parameters of the beams STAGISO or ISO GPS beam :
 Beam intensity is measured between injection and acceleration. If value > 1E13 protons per pulse (for STAGISO) then beam acceleration is “killed” in 1ms
Average (3 mn) number of particles monitored with BCT (Beam Current Transformer) If ppp> 1.E13 (for STAGISO), beam injection is stopped
10/06/2014
ESS Seminar

46. Fragmentation, Spallation, Fission
Target failures
Fragmentation, Spallation, Fission
Tantalum converter
Target container
Container
Target receiving 2.5.E18 protons with a focused proton beam 3.E13 n n n n
10/06/2014
ESS Seminar

47. Water cooling leak test
Target failures
Cooling water leak on target:
Oxydation of tantalum, molybdenum…
Production of H2
Water cooling leak test
10/06/2014
ESS Seminar

48. Broken flange on Front-end due to corrosion:
Other failures
Broken flange on Front-end due to corrosion:
10/06/2014
ESS Seminar

49. Other failures
Failure of target rotation mechanism of CNGS target
2010: 6.7*1019 POT 2.7 MGy
- Rust/pitting corrosion due to use of low grade X46Cr13 balls
- ZrO2 bearings tested and presently under analysis
2012: 3.9*1019 POT ~2.0 MGy
Acknowledgement M.Calvani
10/06/2014
ESS Seminar

50. Thank you for your attention

51. 5th High Power Targetry Workshop
Back up slides
E.Noah et al., Eurisol 100 kw target stations operation and implications for its proton driver beam*, Proceedings of EPAC 2006, Edinburgh, Scotland
22/05/2014
5th High Power Targetry Workshop

52. Back up slides MD beam 500 epA
Use Ne5+ instead of He+
Same A/q
Easier to produce
Lower dose rate
L. Moritz, “ISAC II Safety Report”, TRIUMF, 2006
Acknowledgment : D.Voulot BE/OP