EAPSI: Small-scale testing of nuclear power plant materials

Reichardt Ashley M, Berkeley CA

Investigators

Abstract

As of 2012, a fraction of the world's energy is supplied by nuclear power plants. The interior environments of the reactors supplying this energy are far from benign. Structural materials in nuclear reactors must withstand decades of high temperatures and pressures, corrosive degradation, and damaging neutron radiation in an environment where safety and reliability are paramount. Of particular concern is radiation damage, which is known to cause unwanted hardening and embrittlement in materials, leading to premature failure. Such damage can be simulated quickly in the lab by focusing a beam of protons on a sample; however, since the protons only penetrate the material to very shallow depths, the testable sample size is limited to the micron scale. With such small samples to work with, traditional materials science tests such as tensile testing cannot be easily performed. To solve this problem, a collaborative effort will be made with radiation damage specialist Dhriti Bhattacharyya at the Australian Nuclear Science and Technology Organisation. Using focused ion beam (FIB) milling techniques, micron-scale tensile specimens will be manufactured and tested within a scanning electron microscope (SEM). In addition to providing mechanical property measurements, these tests will allow observations the material's local deformation in real time, providing a wealth of information about the failure mechanism of materials in a reactor setting. Microstructural investigations of tested specimens using transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD) can also be performed to provide further information about the deformation mechanisms involved. Not only will micro-tensile testing have a wide variety of applications in materials research as a whole, but it will also allow a greater number of labs around the world to safely conduct research with small amounts of irradiated and radioactive materials. This NSF EAPSI award is funded in collaboration with the Australian Academy of Sciences.