The scope of this paper is a presentation of the safety issues and of the expected risks associated with the operation of test blanket modules (TBMs) inside the ITER machine. The discussion on the expected risks is done to outline the magnitude of the risks related to the test blankets with respect to the risks expected to operate ITER without the TBMs. The discussion wants to be of general purpose and it does not want to substitute the detailed analyses done in the past and the ones that are presently on going to have a detailed estimation of the risks related to operate test blanket systems (TBSs). Only such detailed analyses will demonstrate compatibility of TBMs with ITER safety requirements. We had reason to address the question on magnitude of TBM risks recently, in conjunction with the preparation of a draft safety reports for the two European TBSs. The key safety issue is associated with unwanted large plasma-disruptions that have the potential to cut right trough the first wall of the TBMs. Such plasma disruptions are currently postulated to occur under several conditions, including the use of the plasma termination system, when called upon to act in response to various initiating events. Under some very unlikely conditions, the through-wall rupture of the test-blanket first wall can lead to exothermic reactions between water/steam and test-blanket materials (lithium and/or beryllium) releasing quantities of hydrogen inside the vacuum vessel. Such releases would be in addition to those estimated for ITER, under similar conditions, but without the presence of the TBSs. The paper discusses this and other safety issues. The conclusion from this work is that the additional risk introduced by the European TBSs is miniscule. This is particularly true if the plasma-physics experiments to be conducted in ITER demonstrate that ITER plasmas are very stable, which, of course, is a necessary condition for a demonstration of fusion power reactor. © 2011 Tonio Pinna. Published by Elsevier B.V. All rights reserved.
All Science Journal Classification (ASJC) codes
- Nuclear Energy and Engineering
- Civil and Structural Engineering
- Mechanical Engineering
- Materials Science(all)