An International Atomic Energy Agency (IAEA) Integrated Safety Assessment for Research Reactors (INSARR) team said the operator of the Hoger Onderwijs Reactor (HOR) in the Netherlands has enhanced safety since a previous review mission in September 2021. The team also found the need to address recommendations related to operational radiation protection and commissioning, following major modifications to the research reactor.

The four-day mission was conducted at the request of the Authority for Nuclear Safety & Radiation Protection (ANVS – Autoriteit Nucleaire Veiligheid en Stralingsbescherming), the Dutch regulatory body, and was hosted by the operating organisation TU Delft Reactor Institute (RID) at the Delft University of Technology. Earlier in April, the 3 MWt research reactor ended a six-month shutdown for the installation of a cold neutron source, which uses very low energy neutrons to study materials with large dimensions. It has since resumed operation to complete the commissioning of the cold neutron source.

The mission team comprised two experts from Argentina and India, as well as one IAEA official. They visited the reactor and its associated facilities and observed resumed operations, reviewed documents and held technical discussions with the reactor’s management and operating personnel.

“RID has addressed most of the review recommendations made in 2021 and achieved significant safety enhancement,” said Kaichao Sun, mission team leader and Nuclear Safety Officer at the IAEA. “Efforts remain needed to ensure the highest level of safety during the ongoing commissioning tests, following the recent major modifications at HOR.”

The team assessed that RID has strengthened the organisational effectiveness and operational programmes through:

  • Completion of an analysis for RID organisational restructuring options and clarification of roles and responsibilities;
  • Revision of operational limits and conditions, with clear distinctions between safety limits and safety system settings;
  • Development of an asset management database for the HOR operating programmes and technical modifications; and
  • Improvement of emergency preparedness by conducting drills.

The findings from the mission indicate the need for continued safety enhancements in areas that are related to:

  • Reassessment and development of a specific set of operational limits and conditions associated with the commissioning stages of testing the new installation of the cold neutron source; and
  • Revision of the area classification and zoning systems for radiological protection, considering the laboratories located within the reactor site.

“This INSARR follow-up mission effectively improved the safety awareness. In particular, the extensive and detailed discussions on the safety assessment gave us new insights on this topic,” said Camiel Kaaijk, Head of Reactor Development Department.

Image: TU Delft Reactor Institute