April 27, 2017: PhD public defence - Petr Grigorev - Assessment of retention of plasma components in tungsten under high flux plasma exposure - UGent

Name: Petr Grigorev

Date: April 27, 2017 10:00 h

Venue: 

Class room 2.1 Irving Langmuir
Technicum (entrance A, block 4, second floor)
Sint-Pietersnieuwstraat 41
9000 Gent 


Assessment of retention of plasma components in tungsten under high flux plasma exposure: multiscale modelling approach

Nuclear fusion can be regarded as a potentially clean, secure and virtually unlimited source of energy for the future. Currently, the most advanced reactor concept – the so-called "tokamak" device employs magnetic confinement of fusion plasma. One of the most ambitious energy-related projects today is the construction of the world’s largest tokamak, also known as ITER, “The Way” in Latin. The experimental campaigns planned at ITER aim at testing integrated technologies, materials and physical regimes necessary for commercial production of fusion-based electricity. In other words, ITER aims at bridging the gap between today’s smaller fusion devices and the demonstrational power plant of the future, the DEMO reactor.

 

One of the main goals for the operation of ITER is to demonstrate the control of fusion plasma with negligible consequences for the environment. Hence, special attention is drawn to tritium (T) regarding its intrinsic toxicity and radioactivity. The limit of 700 g of T accumulated in the ITER chamber was set by the safety authorities in order to limit possible environmental hazards in the unlikely event of T release. A full understanding of the mechanisms governing T penetration, accumulation and retention in the materials that are in contact with plasma is thus important.

 

In the current ITER design, tungsten (W) is retained as armour material for the divertor – the exhaust system of ITER – that is subjected to harsh conditions in terms of heat flux and particle bombardment. The choice of W is mainly motivated by its outstanding properties, such as high melting point, high thermal conductivity and resistivity to sputtering. This thesis focuses on studying the mechanisms of retention and release of T from W under high flux plasma loads by means of multiscale modelling approach.

 
Promotors:
  •  (UGent) Jean-Marie Noterdaeme
SCK•CEN mentor:
  •  Dmitry Terentyev

Click here for a list of obtained PhD degrees.