Neutron noise analysis

Neutron noise analysis can be defined as the direct measurement of the kinetics of a nuclear core. This page describes some of the NEA's previous activities on neutron noise analysis in nuclear power reactors.

Publications and reports
Previous NEA work

Work on neutron noise analysis included:


In 1986, the NEA published the State-of-the-Art Report on Reactor Noise Analysis which provided an assessment of the applicability of noise techniques to power reactor operations, which was drawn up by a working group of the NEA Committee on Reactor Physics in the aftermath of the 1984 SMORN IV symposium in Dijon. Practical applications of noise analysis techniques to plant surveillance have become more widespread, in particular in the areas of loose part detection and vibration monitoring. Theoretical understanding of the methods had also continued to improve.   

MUSE Benchmark

The MASURCA (mock-up facility for fast breeder reactor studies) reactor is an experimental nuclear assembly near the French Cadarache Nuclear Research Centre that could be configured as critical or subcritical reactor by loading a different number of fuel tubes. The core, in the central zone, is based on a uranium/plutonium MOX fuel. The installation was modified for the MUSE-4 experiments, with the addition of an external neutron source based on a deuteron accelerator and the deuterium-tritium or deuterium-deuterium reactions in a target placed in the centre of the fuel core. An evacuated aluminium tube allows the deuterons produced outside the reactor to reach the target. In addition, the MUSE-4 configurations include a central lead region, simulating the spallation target in future ADS. Finally, a reflector region made of a mixture of sodium and steel surrounds the core, and after this a shielding region built exclusively of steel.

Three configurations of the MASURCA facility were simulated in the benchmark. The detailed geometry descriptions and material compositions of each configuration were provided to the participants in the benchmark specifications. A model of the facility has been described and homogenised at the tube level. The errors introduced by the homogenisation approximation were checked by CIEMAT, and they appeared very small, typically from less than 0.1% in keff to a maximum of 8% in the absolute flux at the worst tube (keff = 0.995).


The International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook contains criticality safety benchmark specifications that have been derived from experiments that were performed at various critical facilities around the world. Relatedly, the Handbook has a number of sub-critical measurements, some of which, are accompied by the complete 'list-mode' data that can be used in the development of modelling and simulation tools related to subcriticality and neutron noise.


Ian Hill