English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

english) Understanding the behaviour of molten core material in the lower plenum of the RPV is essential to correctly predict severe accidents in NPPs. Especially for the IVR strategy, which aims to stop the progression of a hypothetical sever accident in the RPV , a detailed description of the phenomena in the lower plenum is necessary. However, current integral codes often use coarse nodalisations and simplified models, which cannot provide the necessary details to evaluate the applicability of the IVR. There is a variety of new special models, which allow detailed and precise descriptions of specific phenomena in a severe accident with the same computational effort as an integral code due to the improved capabilities of current workstations. The Phase-Change Effective Convectivity Model (PECM), as one of these models, was developed based on CFD-investigations of molten core material in the lower plenum at the KTH. This model uses empirical correlations to calculate the convective heat transfer to solve the energy equation. In comparison to the integral approach in the system code MELCOR this model provides a more detailed simulation of the molten material in the same computational time. However, the PECM still cannot capture all heat transfer phenomena in the molten pool. Therefore, an extension of this model was developed to enable the resolution of the stratification in the molten material. Compared to the original PECM approach the S-PECM shows a significant better agreement with the experimental findings in the LIVE-L7v test. To use its capabilities in severe accident simulations, the PECM was coupled to MELCOR. Therefore, the PECM-methodology was implemented into the CFD-software OpenFOAM and then coupled to MELCOR using the developed tool DINAMO. The validation basis for the PECM and the coupled system was expanded by simulating different experiments in the LIVE-facility. The application of the coupled system to the simulation of a severe accident in a generic NPP showed the capabilities of the coupling. The new coupling methodology and the extended PECM allow for more detailed and realistic simulations of molten core material in the lower head of the RPV .

Expansion of the Severe Accident Code MELCOR by Coupling External Models (KIT Scientific Reports ; 7726)