An International Atomic Energy Agency (IAEA) team of experts said the operator of a Dutch research reactor used for research and radioisotope production 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 Integrated Safety Assessment for Research Reactors (INSARR) team concluded a follow-up mission to the Hoger Onderwijs Reactor (HOR) in the Netherlands on 18 April to review the level of implementation of the previous recommendations. The four-day mission was conducted at the request of the Authority for Nuclear Safety and Radiation Protection (ANVS), the Dutch regulatory body, and was hosted by the operating organization TU Delft Reactor Institute (RID) at the Delft University of Technology. Earlier this month, the 3-megawatt 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 of 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 organizational effectiveness and operational programmes through:
- Completion of an analysis for RID organizational 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.
The mission team made a new recommendation on the training programme for the HOR reactor manager.
About HOR
The HOR is mainly utilized for neutron physics, medical radioisotope production, neutron activation analysis, materials irradiation, and education and training. The reactor began operating in 1963 and since then has gone through several modifications, including low enriched uranium conversion in 2005 and refurbishment of nuclear instrumentation and control systems in 2010. In December 2021, the HOR resumed operation after a more than two-year shutdown for the modification programme of its systems and components, including cooling circuits and the containment dome. In October 2023, the HOR was shutdown again to finalize the installation of the cold neutron source and entered the commissioning stages in April 2024.
In 2021, the IAEA and RID expanded their cooperation in neutron activation analysis to neutron beam-based methodologies - a key technique in materials research, biology and medicine. RID was first designated as an IAEA Collaborating Centre in 2010 and has since then supported the IAEA's activities in neutron activation analysis.
About INSARR Missions
