Speaker
Dr
Konstantin Mikityuk
(Paul Scherrer Institut)
Description
Calculational analysis of the unprotected loss of flow (ULOF) accident in a Generation-IV SFR, featuring a low-void core design, shows that the chugging sodium boiling regime in the core could last for several hundred seconds during the accident. While in the case of the traditional positive-void SFR core the sodium boiling onset
is almost immediately followed by the power run-away, fuel bundle overheating, melting and relocation (i.e. severe accident), the chugging boiling regime in the low-void SFR core could allow avoiding the power runaway and avoiding or at least significantly postponing the cladding overheating and melting caused by the permanent dryout. The low-void core design therefore could be classified as a new safety measure acting as a level of defence preventing the severe accidents. The state-of-the-art in the area of the chugging regime of the sodium boiling is very limited and very few corresponding experiments were performed. The paper will present the detailed transient analysis of the low-void core behaviour in unprotected loss of flow accident performed with the TRACE code (modified for the sodium boiling modeling) and discuss the physics of the predicted phenomena as well as the future research needed, including new experiments.
Country/Int. Organization
Switzerland
Primary author
Dr
Konstantin Mikityuk
(Paul Scherrer Institut)
Co-authors
Ms
Anne-Laurene Panadero
(Paul Scherrer Institut)
Mr
Simone Mambelli
(PSI)
