1. Engineering Issues for the NuMI Beamline at 2 MW Accelerator Physics and Technology Workshop for Project X P. Hurh Fermilab 11-12-2007

2. Putting Project X Targetry into Perspective

4. Engineering Challenges for HP Targetry Facilities Thermal Shock/Stress Waves (Liquid and Solid) Heat Removal Radiation Damage Radiation Accelerated Corrosion Remote Positioning Radioactive Component Removal and Repair

5. Thermal Shock and Stress Waves in Target Material Deposition of lots of beam energy into small volume of target material in very small amount of time. Heated area tries to expand rapidly, but is constrained by surrounding material. Creates compressive stress wave that moves radially outward from hot spot. Wave reflects and refracts at target boundaries to create time dependent and complicated stress states.

6. Thermal Shock and Stress Waves in Target Material Simple simulation of stress wave propagation in lithium cylinder.

7. Thermal Shock and Stress Waves in Target Material Can result in failure of targeted material: Fracture of solid from reflected tensile stress wave Cavitation in liquid targets Pressure impulse loading (“water hammer”) on nearby liquid cooling circuits Must design for accident conditions Max intensity and smallest spot size Max rep rate Off-axis (asymmetric) beam on target

8. Thermal Shock and Stress Waves in Target Material Ta-rod after irradiation with 6E18 protons in 2.4  s pulses of 3E13 at ISOLDE (top)

9. Thermal Shock and Stress Waves in Target Material P-bar Run II Target 7 with 8E12 ppp and sigma of ~0.16 mm (oxidation and melting as well!)

10. Thermal Shock and Stress Waves in Target Material NuMI Target- 01 Internal water leak possibly due to “water hammer” effect on bellows

11. Thermal Shock and Stress Waves in Target Material SNS Hg Target Cavitation problems B. Riemer, ORNL

12. Thermal Shock and Stress Waves in Target Material Project X Issues: Target (Jim’s talk) Windows Pre-Target Target US & DS Decay Pipe US “Water hammer”

13. Average Power Heat Removal Not only for materials interacting with primary beam (targets, windows), but also surrounding equipment and shielding. Obviously need to remove deposited energy fast enough to keep temperatures below known limits. Mechanical property degradation Alignment and expansion tolerance Coating and paint combustion

14. Average Power Heat Removal NuMI target chase air cooling for ANU/NOvA 700KW beam power

15. Average Power Heat Removal Project X Issues “Replaceable Systems” Target & Horns Modules Stripline block

16. Average Power Heat Removal Project X Issues “Non-Replaceable Systems” Target Chase - Install water cooled insert plates? Decay Pipe - Utilize redundant cooling circuit, increase flow, circulate He gas in decay pipe? Hadron Absorber - Utilize redundant cooling circuit, increase flow, handle steam generation (800˚C at innermost steel slab)? Heat Rejection RAW systems upgrades (more space needed?) New surface pond required?

17. Radiation Damage Displacements in metal crystal lattice Embrittlement Creep Swelling Damage to organics/plastics Cross-linking (stiffens, increase properties) Scission (disintegrate, decrease properties) Molecular Damage Simulations of peak damage state in iron cascades at 100K. R. E. Stoller, ORNL.

18. Radiation Damage Tungsten cylinders irradiated with 800 MeV protons and compressed to 20% strain at RT. A) Before irradiation B) After 3.2 dpa C) After 14.9 dpa D) After 23.3 dpa S. A. Malloy, et al., Journal of Nuclear Material, 2005. (LANSCE irradiations)

19. Radiation Damage L.K. Mansur, ORNL. 2nd HP Targetry Workshop

20. Radiation Damage Carbon-carbon composite damage at 1E21 proton/cm 2 fluence (N. Simos talk)

21. Radiation Damage Project X Issues Graphite used thus far in NuMI has surpassed 1E21 proton/cm 2 limit for C-C. IHEP study showed that radiation damage should not limit Target lifetime (1 year) for 2 MW operation. Need to study effect on windows! Outside beam spot, dose is not high enough (less than 0.1 dpa) to cause serious concern.

22. Radiation Accelerated Corrosion Radiolysis of air will produce NO 2 which will react with water vapor to create HNO 3 condensate. In addition the radiation fields will enhance hydrogen uptake and permeation. Evaluation of Aluminum, Inconel, and Stainless Steel performed by Savannah River Tech Center for the APT.

23. Radiation Accelerated Corrosion Al 6061 samples displayed significant localized corrosion after 3,600 Mrad exposure. Enhanced tritium uptake and permeation through austenitic Stainless Steel (300 series) R.L. Sindelar, et al., Materials Characterization 43:147-157 (1999).

24. Radiation Accelerated Corrosion MiniBooNE 25 m absorber HS steel failure (hydrogen embrittlement from accelerated corrosion). NuMI target chase air handling condensate with pH of 2. NuMI decay pipe window concerns.

25. Radiation Accelerated Corrosion Photograph of NuMI decay pipe US window showing corroded spot corresponding to beam spot

26. Radiation Accelerated Corrosion Are now filling NuMI decay pipe with helium at just below 1 atm to reduce stress on window and minimize stored energy if a window rupture were to occur. Future corrosion of window may necessitate window replacement or repair.

27. Radiation Accelerated Corrosion Project X Issues Need to characterize corrosive environment Need to analyze all load carrying components from corrosion perspective (crane rails, high strength pins, lifting fixtures, beam windows, etc…) Test materials, coatings, and joining materials for corrosion resistance

28. Remote Positioning Radiation Damage and Accelerated Corrosion combine to create a hostile environment for mechanical remote positioning systems Oil based lubrication gums up Sliding surfaces corrode and seize Cyclic thermal expansions tend to bind mechanisms Pre-stressed elements (springs, bolts, tension rods) are prone to cracking

29. Remote Positioning NuMI Target NT-01 removed from service due to seized bearing on longitudinal positioning system.

30. Remote Positioning P-bar target rotation shaft replacement

31. Remote Positioning Project X Issues Incorporate lessons learned into re-design of modules Identify possible corrosion & wear resistant coatings/platings that can stand up to high radiation environments Investigate use of ceramic bearings and alternative spring materials Incorporate seals, shrouds, and air jets to keep positioning components free from corrosion products (and plating flakes)

32. Radioactive Component Removal and Repair Original NuMI Target Hall Work Cell Design and Radioactive Component Removal Plan were based on 2 key concepts: Work Cell for component change-out only (no repairs) Long term storage of radioactive components in Target Hall shielded pit (“Morgue”) (no removal of components up-shaft) Recent operational experience and ANU (and Project X) plans have altered those fundamental concepts : Work Cell is needed for component repair Radioactive component removal up-shaft for long term storage is required.

33. Target Hall Layout Primary Beamline Target Pile Re-circulating Air Cooling System Target Work Cell MI-65 Shaft Base Horn 1 Horn 2 Low Energy Configuration Stripline Target Pile Shielding Horn 2 Medium Energy Configuration Morgue

34. Existing Work Cell Designed for component replacement, not repair 3 ft concrete side walls Steel door and steel end wall Supports weight of module and component Equipped with Lift Table to unmount/mount components Pb glass windows in beam right side wall and end wall Steel Door Stairs

35. Existing Work Cell Used work cell area to perform 4 component repairs in 1- 1/2 years of operation and only 1 component replacement Predicted dose rates for SNuMI phase 1 components are 300-400 R/hr at 1 foot Horn 1 Residual Dose Rates during water line insulator repair

36. Existing Work Cell Repairs effected by erecting temporary shielding Horn 1 water line insulator repair required 16 techs each performing 6- 12 sec tasks Long handled tools used Requires lots of planning, lots of people and lots of time At higher SNuMI residual dose rates, this solution is not possible

37. Work Cell Upgrade Concept Modular steel shielding extension to Work Cell Tele-manipulator station with Pb glass window Ability to configure shielding to place tele- manipulator station at repair area of component “Portable” Tele-manipulator station to remove manipulators up-shaft for repair and maintenance Requires design of special manipulator tool set Requires incorporation of tool set features in design of new Horns and Targets Contamination issues need to be addressed Requires training of tele-manipulator operators and stocking of tele-manipulator parts Currently in early conceptual design stage

38. RCRP: Short-Term Storage

39. Morgue practically limited to 3-4 components at one time Limited crane coverage Need remote “shelving” to optimize space usage First in, First out desired Allows decay until longer access for up-shaft removal possible

40. RCRP: Transport Cart MI-65 Shaft Base Morgue Shield Plug Crane Coverage Transport Cart must be capable of full weight of largest coffin. If coffins are not used, Transport Cart must be remotely drive-able. If coffins are not used, contamination containers must be used. Many interferences (crane coverage, shield plug, Morgue hatch covers, elevator). Any rails must be temporary to accommodate shield plug and Morgue hatch covers.

41. Radioactive Component Removal and Repair As part of ANU (off project) and NuMI operations, work has been initiated to: Develop shielded tele-mainpulator stations to enable repair on radioactive equipment Develop shielding and remote handling equipment to remove radioactive components from the Target Hall, up the shaft and store in another secure location These systems must be upgraded to handle the dose rates expected for Project X components

42. Radioactive Component Removal and Repair Project X Issues Need to understand shielding requirements for higher dose rate for coffins, morgue and telemanipulator stations Need to find suitable long term storage location (new excavation?). Could possibly use C-0 Assy Hall pit area for long term storage and radioactive component repair/compaction facility.

43. Possible Collaboration Opportunities? Radiation accelerated corrosion study and testing Graphite radiation damage investigation Thermal analysis (and verification testing?) of Target Chase (with cooling panels) and Hadron Absorber Decay Pipe US window replacement Development of radioactive component storage and repair facility at C-0 Target stress wave analysis and testing at P-bar Target Hall (after Run II)

44. Future AP-0 Target Test Facility A future, limited, Target Test Facility is still possible at FNAL using the AP-0 (p-bar source) Target Hall after Collider Run II (2010). Possible beam parameter ranges: 8-120 GeV, 0- 4e13 ppp (1.7e14, Project X), up to 700 kW (ANU) or 2.3 MW (Project X), sigma down to 0.12 mm. Parasitic running with Minerva, Minos, & NOvA required. This may practically limit testing to pulse testing rather than irradiation studies. Need proposals for specific experiments. Act soon; Current plan is to De-commission!