ARIANNE Project

The ARIANNE (Advanced Reactor Investigative Analysis of Neutron Noise Experiments) project aims at testing and assessing the performances of the main neutron noise techniques (Feynman-alpha, Rossi-alpha, and Power Spectral Density) for estimating the kinetic parameters featuring the fast nuclear facility VENUS-F. Neutron noise techniques are very important to monitor the reactor kinetic features during its steady-state operation, ensuring its safe operation. While noise techniques are established methodologies in thermal reactors, their application to fast systems is quite scarce, demanding dedicated experimental efforts.

Due to its simple geometry and low thermal power, VENUS-F is ideal for studying neutron kinetics with noise techniques. The experimental campaign would be performed both in critical and slightly sub-critical configurations, exploiting fission chambers as neutron detectors. The experimental results obtained with the different techniques would be compared one to each other and against high-fidelity, Monte Carlo simulations of the experimental configurations.

The project is expected to contribute to the general know-how of experimental techniques for Gen-IV fast reactors, providing specific insights regarding the range of applicability and associated needs of state-of-the-art neutron noise techniques applied to fast systems.

In addition to the methodological outcomes, the experimental evaluation of the kinetic parameters featuring VENUS-F would be also valuable for the validation of numerical codes and nuclear data libraries applied to heavy-metal cooled fast reactors, like ALFRED and MYHRRA, contributing to the deployment of the Lead Fast Reactor technology.

The objective of the campaign will be to test and assess neutron noise techniques (mainly Feynman-α, Rossi-α and PSDM), generally employed in the case of thermal systems, to a fast nuclear facility like VENUS-F. This campaign will allow us to estimate the kinetic parameters of VENUS-F, and to assess the different noise techniques in the context of fast reactors, getting insights on their performance and on the challenges associated with them. The ARIANNE project will also highlight the need for possible corrections accounting for space and energy kinetics in a fast reactor.

The noise techniques used in ARIANNE will be compared with one another and against high fidelity Monte Carlo simulations of the experiment. The measured kinetic parameters are expected to provide useful insights about the physics of VENUS-F and of heavy-metal cooled fast reactors. In this respect, the experimental estimation of the kinetic parameters at VENUS-F would enrich the set of benchmarks that can be used for the Verification and Validation (V&V) of numerical and experimental methods, codes and nuclear data libraries, which is crucial step for the deployment of lead- and lead-bismuth-cooled fast reactors (e.g. ALFRED and MYRRHA).