The NEA Working Party on Scientific Issues and Uncertainty Analysis of Reactor Systems (WPRS) concluded the 2026 WPRS Week, bringing together around 85 experts from member countries to advance key international activities in reactor physics, thermal‑hydraulics, radiation transport and shielding, and multiphysics modelling.
Held from 17-20 February 2026, the WPRS and four of its affiliated bodies met to review progress on benchmark exercises, data preservation initiatives, and to co-ordinate cross‑cutting technical work essential to the safe and efficient deployment of current and future reactor systems.
Delegates of the NEA Working Party on Scientific Issues and Uncertainty Analysis of Reactor Systems (WPRS)
Highlights of the week included:
- The first annual meeting of the Technical Review Group (TRG) of the Shielding Integral Benchmark Archive and Database (SINBAD), which reviewed the status of ongoing benchmarks and proposed new benchmarks and a pilot initiative to implement machine‑readable data format to SINBAD.
The first annual meeting of the Technical Review Group (TRG) of the Shielding Integral Benchmark Archive and Database (SINBAD) - The NEA Expert Group on Reactor Core Thermal-Hydraulics and Mechanics (EGTHM) meeting, which reviewed progress on thermal‑hydraulics benchmarks on high temperature gas reactor and liquid metal fast reactor concepts and reinforced co-ordination with the NEA’s Committee on the Safety of Nuclear Installations (CSNI) and activities of the International Atomic Energy Agency (IAEA).
The NEA Expert Group on Reactor Core Thermal-Hydraulics and Mechanics (EGTHM) meeting - The NEA Expert Group on Physics of Reactor Systems (EGPRS) session, which discussed ongoing neutronics benchmarks on light water reactor (LWR) and sodium fast reactor (SFR) systems as well as a time‑dependent neutronics activity. A new international Heat‑Pipe Microreactor (HP‑MR) Benchmark has been launched, attracting strong interest from members. Experts and delegates also explored proposals for new reactor‑physics initiatives.
The NEA Expert Group on Physics of Reactor Systems (EGPRS) meeting - The NEA Expert Group on Reactor Systems Multi-Physics (EGMUP) meeting, which examined advancements in coupled multiphysics benchmarks, new proposals related to small modular reactor (SMR) and molten salt reactor (MSR) modelling, and ongoing work by task forces on artificial intelligence and machine learning applications and on fuel‑temperature assumptions in depletion analysis.
The NEA Expert Group on Reactor Systems Multi-Physics (EGMUP) meeting - The 23rd Annual WPRS Meeting, which reviewed expert‑group outcomes, national reports from delegates, updates from the NEA Nuclear Science Committee and the IAEA, as well as the status of the WPRS mandate, upcoming cross‑cutting initiatives, and the 2026 SINUS training.
Collectively, these discussions underscored the NEA members’ commitment to supporting robust, internationally harmonised methods for uncertainty analysis, validation of reactor‑system modelling, and high quality data preservation. The outcomes of the 2026 WPRS Week will guide collaborative technical work in the coming year, helping member countries strengthen the scientific foundation for design and licensing of advanced reactor technologies.
