Applications of Demokritos TANDEM Accelerator in

Fusion Technology Research

TANDEM LabI.N.P.P

M. AndrianisS. HarisopoulosA. LagoyianisG. Provatas

National Centre for Scientific Research “Demokritos”

NuPECC Meeting, Athens, Greece, March 2015

Fusion Technology GroupI.N.RA.S.T.E.S.

G. ApostolopoulosZ. Kotsina

V. LukianovaK. Mergia

S. MessolorasI.E. Stamatelatos

P. TsavalasT. Vasilopoulou

Materials for Fusion Energy Production– Radiation damage of materials– Ion irradiations of fusion materials– Plasma Facing Materials

Activation Properties of CERN Structural Materials

Outline

Materials for Fusion Energy

The long-term perspective of the European Fusion Programme (EUROFUSION in H2020) is to achieve electricity production from the D+T fusion reaction.

A major challenge for the realization of the fusion power reactor (DEMO) is the development of materials capable of withstanding the intense neutron radiation.

DEMO DEMO Fusion Fusion reactorreactor

Radiation Damage Radiation Damage of materials during of materials during DEMO operationDEMO operation

Radiation Damage in Fusion Materials

• Microscopic radiation damage processes:– Atomic displacement and lattice disruption– Transmutation products: He & H– Activation

• Accumulation of radiation damage leads to Macroscopic effects:– Dimensional instabilities, swelling, bubbles,

voids– Reduction in thermal & electrical conductivity– Deterioration of mechanical properties,

hardening, embrittlement

Effects of 14 MeV fusion neutrons on materials

Atomic displacement

SwellingVoid/BubbleFormation

Operating conditions

First Wall Dose (dpa) Temperature

ITER Austenitic steel <3 dpa <300 oC

EUROFER 50-89 dpa <550oC

ODS Ferritic Steels 100-150 dpa <750 oC

SiCf/SiC Composites 100-150 dpa upto 1100oC

DEMO

ITER DEMO

Fusion Materials Research

• Research is conducted world-wide for the development of materials capable of withstanding fusion conditions

• A serious drawback is the lack of suitable neutron sources for testing under realistic conditions

• Ion accelerators are widely used to simulate irradiation conditions in a fusion plasma.

• At the Demokritos TANDEM accelerator irradiations of fusion materials are carried out with the aim to study fundamental radiation damage properties.

• The results are used for the validation of theoretical models developed within the MAT-IREMEV project (Integrated Radiation Effects Modeling & Experimental Validation) that operates under EUROFUSION

Ion Irradiation of Fusion Materials

Development of the new materials irradiation facility “IR2” with unique capabilities at the European level

Irradiation at cryogenic temperatures (40K) In-situ damage estimation by real-time

monitoring of the electrical resistivity Rapid in-situ post-irradiation annealing

Radiation damage and recovery of Fe-Cr alloys (prototype alloys for Fusion Reactor structural materials)

Rec

over

y R

ate

(% /

K)

Annealing Temperature (K)

Recovery in Fe-5%Cr after 5MeV proton irradiation at T=50K

Plasma Facing Materials

Plasma facing materials (PFM) are materials exposed in the harsh conditions of the plasma e.g. high temperatures, irradiation fields

TANDEM based nuclear analytical techniques such as Rutherford Backscattering spectroscopy (RBS) Nuclear Reaction Analysis (NRA) Time-of-Flight Heavy Ion Elastic Recoil Detection Analysis (ToF HIERDA)

combined with the application of micro-beam analysis are used to investigate Plasma Facing Materials removed from JET after the Deuterium-Tritium experimental campaign.

PFMs are studied at Demokritos TANDEM accelerator utilizing nuclear analytical techniques

JET (European tokamak)

Evaluation of CERN structural materials activation

Prediction of induced activity and dose rates is important for radiation protection of CERN maintenance personnel.

Evaluation of CERN structural materials activation properties was carried out by sample irradiation with neutrons in the energy range 4 to 11 MeV at Demokritos Tandem Accelerator and measurement of sample induced activity and dose rate.

SiC Girder and supports Experimental set-up

Outlook

Future developments:

• Use of advanced accelerator-based analytical techniques for fusion materials characterization at the nanoscale

• Development of a state-of-the-art materials irradiation chamber for radiation damage and ion beam modification

• Dual-beam irradiations for simulation of fusion conditions

Thank you for your attention