Investigative study of the radiation damage on fuel clad of miniature neutron source reactor using computational tools

Core conversion requires some evaluation of the reactor safety. Changes to the reactivity worth, shutdown margin, power density and material properties are crucial to the proper functioning of the reactor. The focus of this article is to study the neutron flux distribution in the reactor core and radiation damage on candidate clads. The Ghana Research Reactor-1 (GHARR-1) operates at maximum power of 30 kW in order to attain a flux of 1.0× 1012 n·cm–2·s for the high enriched uranium core. Using the GHARR-1 core geometry, considering 348 fuel pins, the multiplication factor (Keff) is calculated at enrichments of 10%, 12.5%, 16%, 20%, 30% and 90.2%. The spectrum of neutron flux generated in the 26 group is also calculated at the specified enrichments. The ion/particle interactions with the targets (clad) were studied in the Stopping and Range of Ion in Matter code to establish the best clad material based on recorded defects and vacancies generated. From the calculations and simulations, the best choice from the candidate clads based on the assessment is SiC. The calculation of the fuel campaign length gives 7.5 years. The defects sustained by the prospective clad showed low susceptibility to swelling and other forms of deformation.

Experiment and Codes to Support Safety Assessments for Sodium Fast Reactors (KASOLA, SOLTEC and KARIFA)

The experimental liquid metal (LM) loops hosted within the Karlsruhe Sodium laboratory (KASOLA) com-prise a set of facilities to study Liquid Metal (LM) flows for various types of energy applications ranging from room temperature conditions used for education and training and fundamental research up to challenges posed by multi-physics problems such as material-fluid interactions at high temperatures. Extreme conditions, such as sodium boiling, relevant to thermo-electric conversion or fast reactor safety are covered in a dedicated facility small -scale (KARIFA). The complete experimental range is comple-mented by system code support and CFD simulation. The outcome is used for validation and develop-ment allowing application not only on component but also on system scale.

Optimization of the European Sodium Fast Reactor Secondary Sodium Loop as Part of the ESFR-SMART Project

Based on feedback from existing reactors and current projects, the European Sodium Fast Reactor Safety Measures Assessment and Research Tools (ESFR SMART) project proposes an optimization of the secondary circuit with the main aim of improving safety. Besides, the optimization also leads to a simplification of the circuits and therefore to a reduction of the cost of the reactor. For the implementation of the proposed new design option, some points require further R&D to validate their feasibility.

Micromagnetic Microstructure- and Stress-Independent Materials Characterization in Reactor Safety Research

Reactor safety research aims at the safe operation of nuclear power plants during their service life. In this respect, Fraunhofer IZFP’s micromagnetic multiparameter, microstructure, and stress analysis (3MA) has already made a significant contribution to the understanding of different aging mechanisms of component materials and their characterization. The basis of 3MA is the fact that microstructure and mechanical stress determine both the mechanical and magnetic material behavior. The correlation between features of magnetic and mechanical material behavior enables the micromagnetic prediction of mechanical properties and stress, both of which can decisively influence the service life. The Federal Ministry for Economic Affairs and Energy (BMWi) funded this research, handling the mutually superimposed microstructural and stress-dependent influences, a substantial challenge, especially under practical conditions. This superposition leads to ambiguities in the micromagnetic features. The 3MA testing system has been extended by more sophisticated evaluation methods being able to cope with more complex datasets. Investigations dealing with the expansion of the feature extraction and machine learning methods have led to a more precise distinction between microstructural and stress-dependent influences. This approach provides the basis for future applications in reactor safety.