Speaker
Description
The Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA) is a flexible experimental facility being designed at SCK CEN, Mol, Belgium. It is conceived to operate both in sub-critical mode, as an Accelerator Driven System, and in critical mode, as a lead-bismuth cooled fast reactor.
In order to comply with MYRRHA reactor design requirements, uncertainties must be quantified. In nuclear reactor design the uncertainties mainly come from material properties, fabrication tolerances, operating conditions, simulation tools and nuclear data. Indeed, the uncertainty in nuclear data is one of the most important sources of uncertainty in reactor physics simulations, and significant gaps between the uncertainties and the target accuracies (i.e., maximum acceptable uncertainties for a certain parameter) have been systematically shown in the past. Meeting the target accuracy is required not only to achieve the requested level of safety for MYRRHA, but also to minimize the increase in the costs due to additional safety measures.
Target accuracy assessments allow identifying nuclear data needs and requirements (by nuclide, nuclear reaction and energy channel). Since the accuracy and priorities strongly depend on the assumed initial uncertainty data and since numerous nuclear data libraries with updated uncertainty evaluations have been released in the recent years (i.e., ENDF/B-VIII.0, JEFF-3.3, TENDL-2019) and new evaluations are currently being produced, such as JEFF-4 and JENDL-5, it is necessary to provide updated target accuracies for advanced reactor design parameters and nuclear data.
Therefore, in this work we present a Target Accuracy Requirement Assessments of the latest MYRRHA reactor design. The capability of calculating the uncertainty data requirements has been implemented in SANDY, a Python package that can read, write and perform a set of operations on nuclear data files written in the standard ENDF-6 format. Afterwards, SANDY has been used to perform Target Accuracy Requirement Assessments on a homogenised on fuel assembly level MYRRHA reactor model with JEFF-4T0 and other state-of-the-art nuclear data libraries. Nuclides and reactions in need of improvement have been identified to provide feedback to the NEA Nuclear Data High Priority Request List and the JEFF community.