Tóm tắt

An unfolding method based on sparse representation is proposed and applied to unfolding problem ofrnmultiple activation foils measurement. The Online Dictionary Learning (ODL) algorithm is applied forrnsparse representation. The algorithm LARS-EN is used for reconstruction. The Akaike’s InformationrnCriterion (AIC) is applied to select the best coefficient path. Nuclear reactor of Qinshan phase II nuclearrnpower plant (NPP) is considered as the study object and training samples are generated by MonternCarlo code MCNP. By using the unfolding method proposed in this paper, two sets of neutron spectrumsrnare unfolded successfully with acceptable accuracies. The first set contains 4 neutron spectrums of differentrnshapes; and the second set contains 4 neutron spectrums at different positions of the radiationrnsurveillance capsule. Moreover, neutron spectrums of the radiation surveillance capsule can also bernunfolded with acceptable accuracies with fewer equations while the two fission detectors 238U andrn237Np are removed.