ISSN: 1546-962X
Page Count: 11

Determination of Adjusted Neutron Spectra in Different MUSE Configurations by Unfolding Techniques
Plaschy, M
Reactor Physicist, Laboratory for Reactor Physics and Systems Behaviour (LRS), Paul Scherrer Institute (PSI),

Destouches, C
Research Engineer, Commissariat à l'Energie Atomique (CEA), Nuclear Energy Direction, (DER/SPEx/LPE),

Chawla, R
Professor, Ecole Polytechnique Fédérale de Lausanne (EPFL),

Beretz, D
Experimental Programmes Laboratory Member, Commissariat à l'Energie Atomique (CEA), Nuclear Energy Direction (DER/SPEx/LPE),

Mellier, F
MUSE Project Coordinator, Commissariat à l'Energie Atomique (CEA), Nuclear Energy Direction (DER/SPEx/LPE),

Servière, H

Fougeras, P

Chaussonnet, P

Domergue, C

Laurens, J-M

Philibert, H

Abstract

Investigations of spectrum adjustment by unfolding techniques for different locations of critical and driven subscritical MUSE4 configurations are presented. The current analysis is based on the recent accomplishment of specific foil activation measurements and on the use of the unfolding code STAY'SL in conjunction with IRDF-90 and IRDF-2002 dosimetry libraries. Specific developments have been conducted to consider the uncertainties associated with the determination of the experimental absolute reaction rates and the initial calculated spectrum in the most realistic manner. In this context, the iterative adjustment process for the neutron spectrum is established on the basis of variance/covariance matrices defined for the three types of input parameters, i.e., the experimental reaction rates, the initial spectrum, and the dosimetry nuclear data files. The results highlight the spectral variations between different locations of the MUSE4 cores, in particular the characteristic behavior of a subcritical configuration driven by an external T(d,n)He⁴ (14 MeV neutrons) source.

Keywords:
spectrum adjustment, activation measurements, threshold reactions, MUSE, STAY'SL, IRDF

Paper ID: JAI13443
DOI: 10.1520/JAI13443
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