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Analysis of reactivity effects due to core deformation in a Sodium-cooled Fast Reactor

Moira Coccia

Analysis of reactivity effects due to core deformation in a Sodium-cooled Fast Reactor.

Rel. Sandra Dulla. Politecnico di Torino, Corso di laurea magistrale in Ingegneria Energetica E Nucleare, 2019

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Abstract:

Sodium-cooled fast reactors are very sensitive to core deformation because of their hard spectrum. Fast reactor core is subjected to deformations caused by assembly bowing due to thermal or irradiation-related stresses or also by seismic events. Core assemblies are usually supported by lower grid plates ; their interactions in the upper part are controlled by the restraint core system. This system has to be accurately design in order to avoid uncontrolled compaction and consequent positive reactivity injection, but also negative reactivity effects, caused by radial flowering of the core. In this work, we will analyze different deformed configurations of the core of an axially heterogeneous SFR in order to evaluate the corresponding reactivity changes evaluated with a Montecarlo code and a mechanical code using diffusion to solve neutron balance equation. In particular we will focus on different levels of core compaction and widening, on deformations induced during an explosion transient and on different levels of core flowering (flowering both starting from the central assembly and for a fifth ring assembly).

Relators: Sandra Dulla
Academic year: 2019/20
Publication type: Electronic
Number of Pages: 83
Subjects:
Corso di laurea: Corso di laurea magistrale in Ingegneria Energetica E Nucleare
Classe di laurea: New organization > Master science > LM-30 - ENERGY AND NUCLEAR ENGINEERING
Aziende collaboratrici: CEA-Atomic Energy Commission
URI: http://webthesis.biblio.polito.it/id/eprint/12970
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