A hot steam leak during baking of ASDEX Upgrade – Consequences and lessons learned
ASDEX Upgrade is a midsize tokamak operated since 1991. A scheduled maintenance and enhancement shut down is done about once a year. After pump down and leak search a baking procedure is started to condition the vacuum vessel for plasma operation. During operation the vacuum vessel and all in-vessel...
Gespeichert in:
Veröffentlicht in: | Fusion engineering and design 2021-06, Vol.167, p.112385, Article 112385 |
---|---|
Hauptverfasser: | , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | ASDEX Upgrade is a midsize tokamak operated since 1991. A scheduled maintenance and enhancement shut down is done about once a year. After pump down and leak search a baking procedure is started to condition the vacuum vessel for plasma operation. During operation the vacuum vessel and all in-vessel components are water cooled. This cooling system is also used for baking with hot water at 150 °C. During one of these regular baking periods a hot steam leak appears in November 2017. The detection of the leak has triggered a controlled cool down scenario. Nevertheless, between the appearance of the leak and the identification and closing about 100 L water escaped during the controlled cool down from 150 °C to 65 °C into the torus. A fraction of the hot water was distributed as steam all over the torus and condensed at the coldest parts of the vessel, preferentially in remote ports. In addition, the steam interacts with boron containing layers. The resulting acid steam caused additional erosion.
The paper presents details of damages, actions taken to remove them as well as measures taken to avoid a future steam leak. |
---|---|
ISSN: | 0920-3796 1873-7196 |
DOI: | 10.1016/j.fusengdes.2021.112385 |