In the context of coupled Monte Carlo neutron transport and thermal-hydraulic simulations,the knowledge of the continuous-energy cross-sections at every considered temperatureinvolves a huge memory burden. The key to handle full core coupled calculationsis to replace the memory storage of cross-sections by on-the-fly cross-section evaluations.In this respect, the multipole representation of cross-sections provides a convenientapproach. It allows an exact mathematical expression of most cross-section reconstructionformalisms and easily lends itself to parallel Doppler broadening calculations. Inthis work, theoretical aspects of the multipole representation of the Reich-Moore crosssectionformalism are explained. We present a fundamental result leading to a lowernumber of poles needed to exactly represent cross-sections using this formalism. This allowsconsiderably alleviating the convergence issues associated with the algorithms usedto calculate these poles. Then, we recall the formulas for microscopic cross-sections. Wepresent numerical results concerning exact representations of a nucleus expressed withthe Reich-Moore formalism and containing a large number of resonances : U238. Thecomparison with the NJOY reference nuclear cross-section processing code will also bepresented. Finally we discuss the outline for an upgraded multipole conversion from theMulti-Level Breit-Wigner cross-section formalism.
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