Safe and Swift Monitoring of Nuclear Reactors with Gamma-ray Method

Ensuring the safety and compliance of nuclear reactors worldwide is a critical task that requires innovative monitoring techniques. Traditional methods often involve invasive procedures that can disrupt operations and pose security risks. However, a groundbreaking approach using gamma radiation is changing the game, thanks to a team of researchers at EPFL and the Paul Scherrer Institut (PSI).

Small modular reactors (SMRs) present unique challenges for monitoring due to their compact size and remote locations. Conventional monitoring methods designed for larger facilities may not be adaptable or sensitive enough for SMRs. The new non-invasive technique developed by the research team offers a more efficient way to monitor reactor criticality and composition without physically intruding into the reactor vessel.

Led by Oskari Pakari from EPFL and Professor Andreas Pautz from PSI, the researchers utilized bismuth germanate scintillators strategically placed outside the CROCUS research nuclear reactor. These scintillators allowed them to monitor gamma radiation emitted during the reactor's operation, providing valuable insights into its state without direct interference.

Gamma radiation, a type of electromagnetic radiation produced during nuclear fission, carries crucial information about changes in criticality and fuel composition within the reactor. By focusing on the fluctuations in gamma ray counts through statistical analysis, the new method offers a unique perspective on the reactor's operational state, different from traditional neutron-based approaches.

One of the key advantages of this innovative monitoring technique is its ability to provide essential data within minutes, a significant improvement over traditional methods that require longer measurement times and closer proximity to the reactor core. By leveraging computational tools to analyze temporal and spatial variance in detected gamma rays, the method enables rapid and accurate assessments of the reactor's condition, enhancing safety and efficiency in nuclear monitoring.