ion beam accelerators and their application to radiation science … - andy smith... ·...
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Ion Beam Accelerators and their
Application to Radiation Science and
the Nuclear Industry
Andy Smith | Dalton Cumbrian Facility
University of Manchester
Outline
• Dalton Cumbrian Facility (DCF)
– What it is and primary science interests
– Facilities at DCF for Irradiation and characterisation
• Ion Beam Accelerators at DCF
• Science interests and capabilities
DALTON CUMBRIAN FACILITY
Dalton Cumbrian Facility
(DCF)
Radiation science facility which provides a unique
experimental research capability for the UK:
• Fundamental academic research hub for radiation science, with
particular emphasis on tackling problems relevant to the nuclear
industry throughout the fuel cycle
Location of DCF
Science Interests
• Radiation damage of materials
– Existing materials used in current plant
– New materials being developed for use in existing
plant and new plant (inc. Gen IV & fusion)
• Radiation chemistry of processes
– Used in processing throughout the fuel cycle
• Radiation effects on biology
• Robotics for harsh environments
Irradiation Equipment -
Gamma
5MV Ion Beam Accelerator
High dose rate 60Co planar gamma irradiator
• Absorbed dose rates of >20 kGy/hr down to <100 Gy/hr
• 9 litre sample chamber incorporating three turntables & two 19mm
access ports for connection to external experimental rigs
Material Development &
Characterisation
5MV Ion Beam Accelerator
• Mechanical preparation: Wide range of manual & automated cutting,
grinding & polishing/electropolishing equipment. Ball mill. Glovebox.
• High temperature laboratory: Tube furnace, High temperature vacuum
furnace, Spark Plasma Sintering
• Characterisation: FEGESEM incorporating EBSD, WDS & EDS, plus
heating/cooling & tensile stage; 2D-XRD; Time-domain thermoreflectance; a
range of optical microscopes; micro hardness testing; FT-IR Spectrometery;
FT-Raman Spectrometery/Raman Microscopy; Positron Annihilation Lifetime
Spectroscopy (PALS).
• Analytical Laboratory: A range of analytical equipment including: HPLC, Ion
Chromatography; Gas Chromatography; Surface Area & Porosity Analyser
(BET Method); Fluorescence Spectrophotometer; UV-Vis Spectrometer; Total
Organic Carbon & Nitrogen Analyser etc.
ION BEAM ACCELERATORS
Ion Beam Accelerators
5MV Ion Beam Accelerator
Ion beam accelerators producing a wide
range of ion species, energies and fluence
• 5MV tandem ion accelerator (NEC Pelletron
15SDH-4)
– High current TORVIS source providing
10 MeV 1H+ at up to 100 µA, 15 MeV 4He2+ at up to 15 µA
– Low current MC-SNICS source providing
partially and highly stripped heavy ions
e.g. 35MeV 58Ni6+ at ~1 µA
• 2.5MV single-ended accelerator (NEC
Pelletron 7.5SH-2)
– Light ion accelerator (e.g. 1H+ and 4He2+);
dual beam end station under
development
Layout of the accelerator
systems
5MV Ion Beam Accelerator
Ion beam Irradiation
Equipment
5MV Ion Beam Accelerator
Beam lines
• High beam energy/high beam current experiments– Beam line “hot cell” to allow higher penetration & higher damage rate studies
– Equipment for the handling, storage & onward transport of activated samples
• Ion beam analysis : PIXE, RBS, NRA & ERDA
• In-situ measurements : High temperature & pressure corrosion loop,
Raman spectroscopy
RADIATION DAMAGE
Science topic
Radiation tolerance of
materials
• Materials in current use in plant
– e.g. steels, graphite
• New materials for use in existing and future plant
– e.g. Ta alloys, Va alloys, W alloys, MAX phases
• Materials for use in decontamination and
possible long term storage / disposal
Beam requirements
• 1 – 10 MeV p+,
– recent work primarily 1.6 – 2.5 MeV p+
• Typically 10 – 30 μA on sample
• Temperatures up to ~600°C
• In vacuum 1x10-8 T – 1x10-6 T
• Irradiations from 10 min to > 50 hours
• Rastered beam - usually
• Heavier ions available on request
– He, C, Ti, Fe, Ni, Cu, Kr, Mo, Xe, Au + others
– Heavy ions – up to 35 MeV available
Irradiation end station
I. Ipatova et. al. “Radiation-induced void formation and ordering in Ta-W alloys” J.Nucl.Mater. 495 (2017) pp.343-350
P.T. Wady et.al. “Accelerated radiation damage test facility using a 5 MV tandem ion accelerator” NIM.A 806 (2016) pp.109-116
345 ± 3°C
Radiation tolerance of Ta
alloys
I. Ipatova et. al. J.Nucl.Mater. 495 (2017) pp.343-350
• Ta, Ta+5%W, Ta+10%W
– Emergence of interstitial dislocation loops at 0.1 dpa
in all 3 materials
– presence of W seems to delay the evolution of the
dislocation loop structure
TEM of irradiated pure Ta
I. Ipatova et. al. J.Nucl.Mater. 495 (2017) pp.343-350
SMoRE-II (IAEA CRP)Accelerator Simulation and Theoretical Modelling of Radiation
Effects
• IAEA sponsored ‘round robin’
– Comparison of ion beam irradiated and neutron
irradiated sample
– T91 boiler steel, neutron irradiated in BOR-60 to 35
dpa @ 450 °C
– 1 of 13 accelerator labs
– Irradiate with 5 MeV Fe ions
– Sample irradiation completed and currently being
prepared for TEM analysis
RADIATION CHEMISTRY
Science topic
Ion Induced
Radiation Chemistry
• Overall Aim
– Determine fundamental, mechanistic understanding
of radiolytic degradation & modification of materials
– Problems relevant to nuclear industry to inform better
technological solutions
collimator
cellhumidifier
valves
Radiation type: H+, He2+ … ions;
Irradiation conditions: inert or aerated;
Cell (for liquids): glass with a thin mica window;
Cormet autoclave setup for HTHP experiments;
Dosimetry: direct charge collection;
Beam current: 1-10 nA, up to 100 nA for solids;
Characterisation techniques: gaschromatography; mass spectrometry; UV-vis, Raman and FTIR spectroscopy; XPS, XRD, SEM and TEM.
Example of typical experiment
Radiolysis of Nitric Acid
Nitric acid is integral to the reprocessing of irradiated fuel and
is present in a number of areas of Plant.
HNO3 has complex chemistry:
Thermal Degradation
UV Degradation
Redox Chemistry
Radiolysis
Production of Nitrous Acid
HNO3
HNO2 is a major product of HNO3 radiolysis:
H•+ NO3•
HNO2 + O2
HNO2 + O
HNO2, NO2•,H+, H•,
H2, OH•, e-(aq)
Direct
Indirect
The problem with Nitrous Acid
• HNO2 is redox active
Effects corrosion rates
HNO2Np(V) Np(VI)
HNO2
Np(V)NO2
• + H+
HNO2Pu(III) Pu(IV)
HNO2Ce(IV) Ce(III)
NO2• + H+
Effects extraction of actinides in reprocessing
Liquid Irradiation Cell
Adhesive
Mica window
+
HNO3
Degradation of
adhesive
+
HNO2
Answer: New adhesive; Masterbond EP21ARHTND
Laverne & Schuler J.Phys.Chem. 91 pp.6550–6563 (1987)
Proton Irradiation
Experimental Conditions
• 4 Concentrations of HNO3: 0.1, 1, 4 & 6 M
• H+ ions of 5 MeV energy
• Dose rate: 0.25 Gy s-1
• Analysis by Shinn method
Results –
Comparison to literature
• There is no literature data on H+ ion irradiated HNO3 solutions to compare the data to.
• H+ ions have a LET that lies between alpha and gamma radiation.
Particle SourceEnergy(MeV)
Average LET in Water
(keV m-1)
H+ Accelerator 3 21
He2+ Accelerator 3 180
210Po 5.3 136
60Co 1.25 0.27*Values taken from Spinks and Wood 1990
Results
31/10/2016
[HNO3](M)
G(HNO2)(mol J-1)
0.1 0.014
1 0.013
4 0.102
6 0.333
Conclusions
• Results in line with literature values up to 4 M HNO3
• Results at 6 M HNO3 are likely effected by reaction with the adhesive
• Working on a new design of cell to remove adhesive element
Screwthread capwith aperture
Glass disc
GL25Screwthread
tube
O-ring
Acknowledgements
Iuliia Ipatova, Enrique Jimenez-Melero
Holly McKenzie, Alex Baidak, Glenn Trownson,
Howard Sims, Robin Orr and Fiona McLachlan
Accelerator Team : Paul Wady, Samir Shubeita,
Nick Mason
Staff, academics, post-docs and students of DCF
& University of Manchester
Other applications for
accelerators in the nuclear
sector
• Accelerator driven sub-critical (thorium) reactors
• High level waste disposal
– Long lived short lived (e.g. 135Cs (τ½ = 2.3e6a) to 134Cs (τ½ = 2.07a) )
– ‘Useless’ waste useful radionuclides (e.g.
medical isotopes for imaging or radiotherapy)
– Want a range of beams : proton, alpha, gamma,
neutron to exploit different transmutation pathways
