Upgrade of apollo3® internal thermohydraulic feedback model with THEDI, and application to a control-rod ejection accident

Cyril Patricot (1, 2) , Roland Lenain (1, 2) , Dominic Caron (2, 1)

1 LPEC - Laboratoire de Protection d'Etudes et de Conception
2 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

In the frame of APOLLO3 ® project (new generation CEA code system for core physics analysis based on deterministic neutron transport), it was decided to develop a new internal thermohydraulic feedback model: THEDI, a multi-1D, two-phase flow solver. This paper is dedicated to the presentation of the integration of THEDI in the APOLLO3 ® code. After a brief presentation of THEDI and of its APOLLO3 ® 's interface, some code-to-code verification cases are presented. First, APOLLO3 ® , using THEDI, is compared to CRONOS2 (a neutronic CEA code of the previous generation with its own feedback model) for steady-state and depletion calculations on a small PWR core. Then, APOLLO3 ® is compared to a CRONOS2-FLICA4 (a two-phase, four-equation three-dimensional thermohydraulic CEA code) coupling for control-rod ejection accidents, on a similar core. The objective of these comparisons is to verify the coupling between APOLLO3 ® neutronic solvers and THEDI. They are therefore all made with identical models and data, and they all lead to very close results. Thanks to THEDI integration, APOLLO3 ® 's capabilities to model a nuclear reactor core are improved. Thermohydraulic feedbacks can now be taken into account, in both steady-state and transient, for possibly diphasic flows.

Mots clés: APOLLO3 ®; THEDI; multi-physic coupling; control-rod ejection; CORPUS SALOME

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

Cyril Patricot, Roland Lenain, Dominic Caron. Upgrade of apollo3® internal thermohydraulic feedback model with THEDI, and application to a control-rod ejection accident. M&C2019, ANS, Aug 2019, Portland, United States. ⟨cea-02623807⟩