Thermal and structural analysis of W-7X first wall graphite tiles under direct NBI loads

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F25%3A00390613" target="_blank" >RIV/68407700:21220/25:00390613 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1016/j.fusengdes.2025.115178" target="_blank" >https://doi.org/10.1016/j.fusengdes.2025.115178</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.fusengdes.2025.115178" target="_blank" >10.1016/j.fusengdes.2025.115178</a>

Result language

angličtina

Original language name

Thermal and structural analysis of W-7X first wall graphite tiles under direct NBI loads

Original language description

Thermo-mechanical analysis of the Wendelstein 7-X neutral beam dump is presented focusing on failure phenomena resulting from strong impulsive thermal loading of the graphite tiles. One of the plasma heating systems of the Wendelstein 7-X stellarator is Neutral Beam Injection (NBI). There are two NBI boxes with currently a total injected hydrogen beam power of 7 MW and a pulse length up to 5 s. Each NBI box can be operated with four positive ion neutral injectors (PINI). A total of three PINIs were used simultaneously in the last operation campaign in 2022. NBI is highly important for the W7-X physics program, thus increasing NBI power is planned in the next operation phase. A portion of the NBI power passes through the plasma, creating a region of the first wall (FW) with a significantly increased heat load. This region, called the beam dump, could be a limiting factor for the NBI pulse length and thus it requires a precise remodeling of all constituents before the 2024/2025 operation phases to prevent repeated structural damage to this area. Since the graphite tiles are attached by multiple bolts to the CuCrZr heat sinks, the thermal expansion of graphite can induce significant stress in the graphite. The safety limiting factor is the induced thermal stress in the graphite tile due to the NBI beam power load. ANSYS Mechanical model was developed, including the bolted connections, and analyzed to examine the effect of the heat load on the FW components and to evaluate the maximal allowed duration of the NBI beam. A coupled transient simulation of the thermal and structural analysis is performed. The calculation used the NBI heat loads on the FW surfaces estimated by the BEAMS3D code. This paper presents the results of the numerical analysis and the related operating limits.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

20305 - Nuclear related engineering; (nuclear physics to be 1.3);

Project

<a href="/en/project/TS01030051" target="_blank" >TS01030051: Innovative shield against extreme heat fluxes in thermonuclear fusion and other plasma reactors</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Fusion Engineering and Design

ISSN

0920-3796

e-ISSN

1873-7196

Volume of the periodical

218

Issue of the periodical within the volume

115178

Country of publishing house

CH - SWITZERLAND

Number of pages

10

Pages from-to

2987-2996

UT code for WoS article

001502460400001

EID of the result in the Scopus database

2-s2.0-105005831177