Materials in Nuclear Energy Systems (MiNES) 2021: Versatile Test Reactor
Program Organizers: Todd Allen, University of Michigan; Clarissa Yablinsky, Los Alamos National Laboratory; Anne Campbell, Oak Ridge National Laboratory
Tuesday 8:00 AM
November 9, 2021
Room: Urban
Location: Omni William Penn Hotel
Session Chair: Adrien Couet, University of Wisconsin-Madison
8:00 AM Invited
Overview of in Reactor Mechanical Testing in the Versatile Test Reactor: Tarik Saleh1; Julie Tucker2; Samuel Briggs2; Maria Okuniewski3; Cem Topbasi4; 1Los Alamos National Laboratory; 2Oregon State University; 3Purdue University; 4Electric Power Research Institute (EPRI)
The Versatile Test Reactor (VTR) is a fast spectrum test reactor proposed by the U.S. Department of Energy to provide a relevant experimental environment to test materials in conditions expected for advanced reactors. Instrumented in-reactor fast neutron spectrum mechanical testing is currently very difficult globally due to loss of experimental capability and limited numbers of fast test reactors. The VTR will provide a robust experimental environment for both materials irradiations and in-reactor mechanical and environmental testing. Among a large design team consisting of national laboratories, universities and industrial partners, the materials team, led by Los Alamos National Laboratory, Oregon State University, Purdue University and EPRI, has been working to design in-reactor mechanical testing rigs, associated diagnostics, as well as an open test assembly to house the experiments. This talk will review the status of these mechanical testing designs, environmental considerations, and plans for integrating them in the reactor.
8:40 AM
In Situ Mechanical Testing Method for Materials in Gaseous Environments: Peter Beck1; Jake Quincey1; Dustin Mangus1; Adam Koziol1; George Young1; Guillaume Mignot1; Samuel Briggs1; Julie Tucker1; 1Oregon State University
Advanced heat transfer fluids (such as He, supercritical CO2) for Gen IV reactor designs are being considered for their increased efficiency and power density at high temperatures. In situ mechanical testing of structural materials is needed to qualify materials for safe use in reactor designs. Simulated operating conditions make such work challenging due to high temperature, pressure, and geometric constraints impeding traditional crack growth testing. This work presents a novel, low-profile mechanism for crack growth testing in reactor environments, featuring a metal bellows and using a modified electric potential drop method. This compact device can be deployed in-core and will enable environmentally assisted crack growth testing. Low-cycle fatigue tests are performed on 316/316L stainless steel in a variety of elevated temperature (550°C) gaseous environments, including air, He, and supercritical CO2. Analogous tests are conducted in a traditional load frame to compare and validate the new testing method.
9:00 AM Cancelled
Emissivity Measurements of Silicon Carbide Cladding Samples for Use in Gas Cooled Fast Reactor: Noah Sutton1; Rodolfo Vaghetto1; Yassin Hassan1; Piyush Sabharwall2; 1TA&M Thermal Hydraulics Lab; 2Idaho National Laboratory
There is a strong need for further characterization and measurements of thermal properties of the materials to be tested in the Gas Cooled Fast Reactor (GFR) cartridge during irradiation test campaigns that will be conducted at the Versatile Test Reactor (VTR). Due to high operating temperature, radiation heat transfer is expected to play an important role in the GFR core heat transfer, and must be properly characterized. Emissivity measurements of cylindrical silicon carbide cladding samples have been conducted to study the dependency on the operating temperature and surface roughness. The measurement system is based on infrared technology and utilizes a reference with known properties of emissivity. High-temperature paint, with known emissivity as a function of temperature, was selected as the reference to conduct the measurements and estimate the uncertainty. Emissivity of the samples was measured for samples of two different surface roughness and at temperatures up to approximately 500 °C.
9:20 AM
Design and Operation of an Out-of-pile Liquid Sodium Experimental Facility for Mechanical Testing: Dustin Mangus1; Peter Beck1; Guillaume Mignot1; Wade Marcum1; Julie Tucker1; Samuel Briggs1; 1Oregon State University
The U.S. Department of Energy initiated the Versatile Test Reactor (VTR) program to address the capability gap pertaining to in-pile testing of engineering materials in prototypical environments proposed for the Generation IV fission reactors. Oregon State University (OSU) is performing work to develop a mechanical and environmentally assisted crack growth testing apparatus that can be housed within a fully instrumented VTR cartridge loop. OSU’s newly developed Glovebox for Experimental Liquid Sodium (GELS) facility is an out-of-pile thermal-hydraulic system that can provide purified liquid sodium to experimental loops and vessels within an inert glovebox. Integrated into GELS is the Corrosion Experimental Loop (CEL) which will house a compact loading mechanism to assess the viability of the loading systems' ability to facilitate crack growth in structural alloys tested in liquid sodium media. This presentation will highlight the capabilities of OSU’s GELS facility for materials degradation testing in support of SFR-related research.
9:40 AM
Fracture Mechanics-based Testing and DCPD in FLiNaK: Xavier Quintana1; Jake Quincey1; Peter Beck1; George Young1; Samuel Briggs1; Julie Tucker1; 1Oregon State University
Advanced reactor coolants such as molten salts pose unique challenges for test systems designed to study environmentally assisted cracking (EAC). Challenges with in-situ testing include immersing the sample in molten salt while preventing air exposure and providing sample access for real-time load control and monitoring of crack initiation and growth. An in-situ mechanical test system has been developed that addresses these challenges and is capable of state-of-the-art, fracture mechanics-based EAC testing in molten salt. Slow strain rate and K-controlled fatigue crack growth tests were performed utilizing DCPD for in-situ data collection. Initial tests have been conducted using 316 stainless steel in molten FLiNaK at temperatures up to 700°C. Samples were characterized post-test via scanning electron microscopy to elucidate the salt’s influence on stress corrosion cracking. Inductively coupled plasma-based salt impurity measurements are also used to correlate specimen performance in the salt environment.
10:00 AM Break