NEURAP-A Dedicated Neutron-Imaging Facility for Highly Radioactive Samples

Area of Science:

• Nuclear Engineering
• Materials Science
• Radiation Detection

Background:

• Highly radioactive samples pose challenges for standard imaging techniques due to intense gamma radiation.
• Existing instrumentation for neutron imaging of such materials is scarce worldwide.
• The NEURAP setup at the Swiss neutron spallation source (SINQ) was developed to address these limitations.

Purpose of the Study:

• To detail the NEURAP setup and its specialized procedure for neutron imaging of highly radioactive samples.
• To present key applications of NEURAP in analyzing operational components and nuclear fuel.
• To highlight the insights gained from quantitative image analysis regarding material degradation.

Main Methods:

• Utilizing Dysprosium (Dy)-loaded imaging plates, sensitive to neutrons but not gamma rays.
• Implementing a multi-step process involving neutron irradiation, gamma erasure, and delayed readout of neutron-induced signals.
• Applying quantitative analysis to neutron radiographs of SINQ target components and spent nuclear fuel rods.

Main Results:

• Accumulation of spallation products was identified in SINQ target components.
• Aggregation of hydrogen was observed in spent nuclear fuel pins and their cladding.
• Detailed characterization of material degradation in operational nuclear materials was achieved.

Conclusions:

• NEURAP provides a unique capability for routine neutron imaging of highly radioactive samples.
• The findings contribute to understanding material degradation mechanisms in nuclear applications.
• Optimized operational regimes and extended safe lifetimes for nuclear components are potential outcomes.