Post-Test Numerical Analysis of a Helium-Cooled Breeding Blanket First Wall under LOFA Conditions with the MELCOR Fusion Code

Michela Angelucci,Bradut-Eugen Ghidersa,Mihaela Ionescu-Bujor,Bruno Gonfiotti,Sandro Paci,Robert Stieglitz,Xue Zhou Jin

doi:10.3390/app12010187

Michela Angelucci, Bradut-Eugen Ghidersa + Show 5 more

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https://doi.org/10.3390/app12010187

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Abstract

The validation of numerical tools employed in the analysis of incidental transients in a fusion reactor is a topic of main concern. KIT is taking part in this task providing both experimental data and by performing numerical analysis in support of the main codes used for the safety analyses of the Helium Cooled Pebble Bed (HCPB) blanket concept. In recent years, an experimental campaign has been performed in the KIT-HELOKA facility to investigate the behavior of a First Wall Mock-Up (FWMU) under Loss Of Flow Accident (LOFA) conditions. The aim of the experimental campaign was twofold: to check the expected DEMO thermal-hydraulics conditions during normal and off-normal conditions and to provide robust data for code validation. The present work is part of these validation efforts, and it deals with the analysis of the LOFA experimental campaign with the system code MELCOR 1.8.6 for fusion. A best-estimate methodology has been used in support of this analysis to ease the distinction between user’s assumptions and code limitations. The numerical analyses are here described together with their goals, achievements, and lesson learnt.

Highlights

Two breeding blanket (BB) concepts are under development for the EU DEMO (Demonstration Power Plant): the Helium Cooled Pebble Bed (HCPB) BB concept and the Water
The mock-up is heated in the central zone through to a beam gun, and the Loss Of Flow Accident (LOFA) event is reproduced closing a valve on the outlet header of five channels
This paper reports the activities concerning the validation of MELCOR 1.8.6 for fusion against experimental data investigating the behavior of a First Wall Mock-Up (FWMU) in DEMO relevant conditions

Summary

Introduction

Two breeding blanket (BB) concepts are under development for the EU DEMO (Demonstration Power Plant): the Helium Cooled Pebble Bed (HCPB) BB concept and the WaterCooled Lithium Lead (WCLL) BB concept [1]. The HCPB blanket concept is characterized by EUROFER as structural material, the advanced ceramic breeder material based on a mixture of Li4SiO4 and Li2TiO3, and Be12Ti as neutron multiplier material [2]. The Karlsruhe Institute of Technology (KIT) has performed several experimental campaigns to qualify the HCPB design and to provide experimental data for code validation studies [1,3]. One of these campaigns involved is a First Wall Mock-Up (FWMU) under different Loss Of Flow Accident (LOFA) conditions [4]. Several LOFA scenarios are investigated depending on the percentage of valve opening: valve 60% open, 40% open, 20% open, 10% open, 5% open, and 0% open (full LOFA)

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