Eucard-WP7 HFM collaboration meeting sept F.Rondeaux 1 Radiation hardness studies on resins : some words about cyanate ester F.Rondeaux CEA Saclay - IRFU - SACM - LEAS

Eucard-WP7 HFM collaboration meeting sept F.Rondeaux 2 Before speaking about the details of the tests… Precise the environment: –type of radiation? dose rate? total dose? –Answers will define the scope of the study, the experimental protocole –what is the appropriate reactor?.... Be careful (cf papers from D.Evans and R.P.Reed): –Results depends on radiation spectrum, energy, interaction cross-section, chemical composition of the materials… –Ex: irradiation effects on insulation systems consistent or not between reactors, depending if data plotted versus fast neutron fluence or total dose; –Damages can be underestimated with fast neutrons.  Bibliography : what has been already studied in this area? –already a lot of studies on the behaviour of resins after irradiation, especially connected with developments for ITER, –development of new materials, ex CE/ epoxy blend.  not perform useless studies if a solution already exits.

Eucard-WP7 HFM collaboration meeting sept F.Rondeaux 3 Cyanate ester resins Cyanate Ester / Epoxy Pot life : at least 24hours °C (the time to 100 mPas), about 72 hours, to 200 mPas. Viscosity : initially <100 mPa.s, the increase should not exceed a factor of 2 during the life time. Curing temperature max. : 150°C (/177°C) Safety : toxicity OK, exothermic reaction. Hunstman has developed a 40/60 cyanate ester /epoxy blend resin for the impregnation of the TF coils. radhard (according to the ITER requirements / neutron fluence of 1x10 22 m -2 ) The resin can be used in an industrial VPI process for the coils manufacture. (tested on the RESDEV mock-up).

Eucard-WP7 HFM collaboration meeting sept F.Rondeaux 4 Radiation tests results from ATI For years, ATI (Atomic Institute of the Austrian Universities, Vienna) has tested different insulating materials for the coils of ITER. –samples produced by Alstom, Ansaldo, –resins of CTD, Huntsman…. Irradiation in reactor TRIDA-Mark II –a gamma-dose rate of 1x10 6 Gyh -1, –a fast neutron density of m -2 s -1 (E>0.1 MeV). Mechanical tests at 77 K, at 0° and 90° –UltimateTensile Strength (UTS) –Interlaminar Shear Strength (ILSS) –Fatigue behevior ATI has shown that cyanate ester based insulation systems resists to the neutron fluence of 1x10 22 m -2 (E>0.1 MeV) and beyond (tests to 5x10 22 m -2, which corresponds approximately to a total absorbed dose of 250 MGy).

Eucard-WP7 HFM collaboration meeting sept F.Rondeaux 5

ATOMIC INSTITUTE LOW TEMPERATURE PHYSICS Association EURATOM – ÖAW DGEBA 77 K after irradiation up to 4x10²² m MPa 42 MPa 77 MPa 57 MPa 74 MPa 63 MPa 62 MPa 48 MPa 68 MPa 0° 90° DGEBA Orlitherm 20 % CE 30 % CE 40 % CE 100 % CE DGEBA 58 MPa 81 MPa 75 MPa 45 MPa 41 MPa The result is confirmed also in short beam shear tests. Cyanate ester based resin systems keep reasonable strengths up to a fluence of 4x10²² m -2