FETS-HIPSTER A High-Flux Proton Irradiation Facility Steve Roberts (University of Oxford) Chris Densham (RAL), Alan Letchford (RAL), Juergen Pozimski (Imperial College/RAL) Russell Gwilliam (University of Surrey) NNUF meeting, University of Leeds, 1st September 2014

Neutron-irradiated Unirradiated Ion- irradiated Micromechanical testing Fe-6%Cr – Size effects Yield Stress (GPa) Beam depth (  m) 0.1mm

Neutron-irradiated Unirradiated Ion- irradiated Micromechanical testing Fe-6%Cr – Size effects Yield Stress (GPa) Beam depth (  m) 0.1mm

Proton irradiation for (micro) mechanics? SRIM : 2 MeV protons into Fe Could use specimens 10 – 12  m thick – well beyond the size-dependent mechanics regime 25  m0m0m 0m0m

Proton irradiation for (micro) mechanics? SRIM : 2 MeV protons into Fe 25  m0m0m For 2MeV H + into Fe: Total damage: ~1 x10 -4 events / (Å - ion)  ~10 21 ions cm -2 for 1 dpa Depth ~ 15  m 5m5m 0m0m For 2MeV Fe + into Fe: Total damage: ~4 events / (Å - ion)  ~2 x ions cm -2 for 1 dpa Depth ~ 1  m

Proton irradiation for particle physics? “Front - End Test Stand” Rutherford Appleton Lab. & Harwell Culham: CCFE Oxford Proton Driver Front End for testing the early stages of acceleration (0–3MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories.

Proton irradiation for particle physics? “Front - End Test Stand” Rough specification: 3MeV H- 60mA peak beam current 10% load so 6mA average Spot size ~2 mm diameter (RMS) Can be focused or de-focused if desired – up to ~100 mm spot size Temperature pulses of ~10°C or less, and only small stress pulses (<few Mpa). Beam would deliver about ions s -1  1 dpa / day in top ~20  m over 1 cm 2

Comparison of Proton Irradiation Facilities Energy Proton current Target areaT-rangeReadynessNotes FETS- HIPSTER 3 MeV fixed: upgradable to MeV 6mA average (60mA pulses, 10% duty cycle) undecided, but up to 300mm diameter 300 – 1000C likely Accelerator exists, target area to be designed & commissioned protons only. DCF variable, <1 MeV – 10 MeV 0.1mA~5cm diameter Under development Single beam now, dual beam in late 2015 part of dual –beam facility. Can deliver any ion at micro-Amp current Birmingham cyclotron MeV 60  A Several cm?? Under construction Max run time 6-10 hours – shared with isotope production. Birmingham dynamitron Up to 3MeV1 mASeveral cm?? Under construction Long run times? UK IBC, Surreyup to 2 MeV 3  A (2x10^13 H/s) / 30  A Up to ~40cm diameter Up to 900COperational JaNNUS up to 4 MeV (typically 2.5MeV on Yvette for H + ) 40  A ( 2.5  ions/s) ~2.5cm diameter up to 800COperationalPart of triple – beam facility. HZDRup to 6 MeV µA Up to 10cm diameter? up to 800COperational IMBL, Michigan 400 kV – 3 MeV 1 nA – 50  A ~5cm diameter late 2014.Part of triple – beam facility. MIAMI, U. Huddersfield kV10 10 – ions/cm 2 /s TEM foil OperationalIn-situ irradiation TEM For 2-3 MeV protons, damage rate in the near-surface region is ~10 21 ions cm -2 for 1 dpa: i.e. ~100 Amp.s/cm 2

Front End Test Stand / High Intensity Proton Source for Testing Effects of Radiation Extension of the Front End Test Stand (FETS) proton source already funded and currently being commissioned at Rutherford Appleton Laboratory A world-unique high-intensity (6mA, 3MeV / 18MeV) irradiation facility. Deep (~25 micron), near-uniform radiation damage Up to ~100 dpa per annum Will enable studies of irradiation induced microstructural changes and mechanical properties including: –hardening, –embrittlement, –creep, –fatigue, –stress-corrosion cracking, –thermal property changes Applications in verifying and developing nucleonics codes and in thermal shock loading tests.

FETS-HIPSTER: Capability FETS-HIPSTER would enable study of mechanical properties of materials irradiated up to dpa levels typical of end-of life values for structural fission and fusion reactor materials, and over depths sufficient to perform mechanical property tests giving data directly transferrable to full-scale components. The large irradiation area of several 100s cm2 will permit multiple experiments in parallel, including in-situ tests (creep, fatigue, stress- corrosion). Existing ion and proton irradiation facilities cannot produce this combination of high dose and deep irradiation Data from FETS-HIPSTER experiments will allow pre-screening of materials to be irradiated in future neutron facilities such as the JHR, FAFNIR or IFMIF

FETS-HIPSTER: Future Extension There is also the possibility (beyond this proposal) to upgrade the beam energy to MeV to mimic more closely fusion-spectrum neutrons; The design of the current upgrade would allow for future developments to be able to handle the increased prompt radiation and activation that would result.

FETS-HIPSTER: Costs and Timing More than 50 staff-years of effort and £5-6M have already been spent on the Front End Test Stand. –After a beam physics programme (~1 yr) FETS would immediately be available for application as part of FETS-HIPSTER. Approximate cost of the equipment: £4M –Uses existing FETS accelerator, buildings, and expertise –HIPSTER would add beam transport line, building extension containing shielding, water cooling and air ventilation and a remote handling system, sample environment and beam dump system. Approximate annual running costs: £380k –£220k staff: three posts: one Physics, one technical support and one craft; –£60 k for maintenance, electricity, etc.; –£100k for equipment, e.g. flasks, beam dump spares) The complete design and construction of FETS-HIPSTER would require 3 years. –This process could run in parallel with the existing FETS timeline, so earliest first use could be late 2017 to mid 2018.