Resonant upscattering effects on $^{238}$U absorption rates

Claude Mounier (1, 2) , Pietro Mosca (1, 2)

1 LLPR - Laboratoire de Logiciels pour la Physique des Réacteurs
2 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

The new requirements of accuracy in reactor physics calculations justify a review of the current models, like that one adopted in the cross-section processing, for a better evaluation of the keff and the resonant absorption rates. In this context, the aim of this paper is to investigate the effects of the free gas kernel developed by Sanchez on the $^{238}$U absorption rates. Homogeneous medium tests point out the increase of the absorption rates in the left wing of the resonances due to the upscattering produced by the new kernel. Heterogeneous tests show that the absorption in the left wing of the resonances is mostly affected by the scattering anisotropy in the laboratory system.

Mots clés: Doppler; Free Gas; Resonant Scattering

Domaines: Physique Nucléaire Théorique [nucl-th]; Physique Nucléaire Expérimentale [nucl-ex]

Claude Mounier, Pietro Mosca. Resonant upscattering effects on $^{238}$U absorption rates. PHYSOR 2014 - The ANS Reactor Physics Topical Meeting " The Role of Reactor Physics toward a Sustainable Future, Sep 2014, Kyoto, Japan. ⟨cea-02933119⟩