## Abstract

The Cohn-α and Feynman-Y methods are implemented to analyze critical and subcritical configurations of the MAESTRO core in the MINERVE zero power reactor in order to measure its integral kinetic parameters, i.e. effective delayed neutron fraction β_{eff} and the prompt neutron generation time A, in addition to the absolute reactivity p. Various methods are studied and implemented to obtain the variance-to-mean ratio curves and the cross-correlation power spectral densities (Cohn-α) of the detector's readings. Regarding the Cohn-α method, it is shown that the obtained kinetic parameters are highly sensitive to the numerical parameters used in the power spectra calculations. Despite their pronounce effect, very little considerations are usually given to their values, which are often determined rather arbitrarily. Generally, well-defined methodologies for tuning these parameters is overlooked. In this paper, a new methodology is proposed for analyzing the kinetic parameters' sensitivity to the power spectra calculations and for fine tuning of its numerical parameters in order to evaluate and reduce the associated uncertainty. Regarding the Feynman-Y method, the fitting models include a single-mode prompt reactivity model and a multi-mode delayed reactivity model. A direct derivation of the integral parameters (p and β_{eff} is performed using a novel approach, in which the parameters are simultaneously considered as degrees of freedom within the curve fitting procedure. This novel approach enables a simultaneous direct estimation of β_{eff} and the absolute reactivity p, independent of prior reactivity calibrations, e.g. rod-drop or stable period analysis.

Original language | English |
---|---|

Title of host publication | Physics of Reactors 2016, PHYSOR 2016 |

Subtitle of host publication | Unifying Theory and Experiments in the 21st Century |

Publisher | American Nuclear Society |

Pages | 1172-1185 |

Number of pages | 14 |

ISBN (Electronic) | 9781510825734 |

State | Published - 1 Jan 2016 |

Event | Physics of Reactors 2016: Unifying Theory and Experiments in the 21st Century, PHYSOR 2016 - Sun Valley, United States Duration: 1 May 2016 → 5 May 2016 |

### Publication series

Name | Physics of Reactors 2016, PHYSOR 2016: Unifying Theory and Experiments in the 21st Century |
---|---|

Volume | 2 |

### Conference

Conference | Physics of Reactors 2016: Unifying Theory and Experiments in the 21st Century, PHYSOR 2016 |
---|---|

Country/Territory | United States |

City | Sun Valley |

Period | 1/05/16 → 5/05/16 |

## Keywords

- Absolute reactivity measurement
- Cohn-α
- Feynman-Y
- Integral kinetic parameters
- MINERVE reactor
- Noise techniques

## ASJC Scopus subject areas

- Nuclear Energy and Engineering
- Nuclear and High Energy Physics