Thermomechanical Testing of First Wall Test Pieces in ESURFa

Abstract

This paper reports work performed under Program Element I (PE-I) of the First Wall, Blanket, and Shield Program, the principal objectives of which are the testing of first wall design concepts to support the design of fusion reactor first walls and the verification of analytical techniques and design tools. The test facility, ESURF, consists of a 36 kW continuous duty electron beam, evacuated target chamber, and a 6.9 MPa water loop for active cooling of test pieces. Long pulse ''steady state'' surface heat loads are simulated by rastering the beam in two dimensions, while disruption heat loads are simulated by imposing a focused, stationary beam for a fixed length of time on the target area. Initial test pieces consisted of stainless steel (Type 316) tubes. Tests to date have included thermal-hydraulic characterization of the specimens, thermal cycling up to 500 cycles, disruption heat load simulations, and combined disruption heat loads with thermal cycling. The test results reported here address the verification of predicted thermomechanical response of the specimens, the effects of disruption heat loads on surface melting and crack formation, and the affect of thermal cycling on crack formation/propagation.