Abstract
The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory produces the most intense, pulsed neutron beams in the world for various scientific research experiments and industrial development activities. The neutrons spalled from a mercury target are moderated and directed into instrument channels by the Inner Reflector Plug (IRP), which is designed for the purpose of moderating, reflecting, and shielding these neutrons. The SNS lower IRP is the bottom-most segment of the inner reflector plug components. The lower IRP is a complex structure consisting of an aluminum vessel, beryllium and stainless-steel reflectors, water and cryogenic hydrogen moderators, neutron poisons, and various channels for neutron transport. The lower IRP must be replaced regularly due to consumption of the neutron poisons and embrittlement of the structural materials from radiation. The hydrogen moderators are constructed from 6061-T6 aluminum. Each hydrogen moderator has a vessel with concentric tubing for supply and return of 18K hydrogen. The hydrogen moderator vessel is welded to a connecting tube using gas tungsten arc welding (GTAW). Radiographic Testing (RT) of a moderator vessel during fabrication indicated porosity within the weld but did not define the location or shape of the porosity. For a better definition of the weld defects, the computed tomography (CT) scan technique was used to produce an accurate 3D image of the weld and weld defects. This paper will describe the procedure to incorporate the CT scan porosity data into the finite element model of a hydrogen moderator with a GTAW weld to determine fitness-for-service. The stress analysis was performed to evaluate the weld defects and to qualify the GTAW weld via the ASME BPVC design criteria.
| Original language | English |
|---|---|
| Title of host publication | Design and Analysis |
| Publisher | American Society of Mechanical Engineers (ASME) |
| ISBN (Electronic) | 9780791888483 |
| DOIs | |
| State | Published - 2024 |
| Event | ASME 2024 Pressure Vessels and Piping Conference, PVP 2024 - Bellevue, United States Duration: Jul 28 2024 → Aug 2 2024 |
Publication series
| Name | American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP |
|---|---|
| Volume | 2 |
| ISSN (Print) | 0277-027X |
Conference
| Conference | ASME 2024 Pressure Vessels and Piping Conference, PVP 2024 |
|---|---|
| Country/Territory | United States |
| City | Bellevue |
| Period | 07/28/24 → 08/2/24 |
Funding
The authors would like to acknowledge the contribution of Charlette Barbier for guidance of using SpaceClaim to incorporate the CT scan data. The SNS is sponsored by the Office of Science, U.S. Department of Energy, and managed by UT-Battelle, LLC under contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).
Keywords
- CT scan
- fitness-for-service
- hydrogen vessel
- stress analysis
- weld porosity