The assembly of the core of the International Thermonuclear Experimental Reactor ITER, which is being built near the Cadarache research center on the French Cote d'Azur, has been suspended by decision of the French Nuclear Safety Authority (ASN). This is reported by the New Energy Times.
It was planned that the reactor core would be assembled from nine massive sectors, each of which would weigh 440 tons. Two sectors are already in place, awaiting descent into the reactor chamber, and, according to the work schedule published on the ITER website, the first sector node was to be lowered into the tokamak chamber as early as December 2021, however, at the end of January 2022, the chairman of the board of directors ASN Bernard Doroshchuk sent a letter to ITER Director General Bernard Bigot warning that these sectors could only be installed in the reactor chamber if there was a guarantee that they could be removed later.
The fact is that even during the manufacture, either these sectors themselves, or their parts, were damaged during a fall and, possibly, seriously deformed. Welding these sectors inside the tokamak pit would be an irreversible operation that required official ASN approval, but in the absence of the aforementioned guarantees, tokamak assembly cannot be authorized. Experts believe that due to distortions in the structure, it is impossible to assemble the sectors in a planned manner in a spacious assembly hall. Instead, ITER proposed that this work be carried out inside a confined space where the final assembly of the reactor core would take place. If the sectors cannot be welded together properly, there is a risk of excessive radiation being released during reactor operation. Protecting personnel from gamma radiation and neutrons that are generated during ITER operation requires proper connection of the nine sectors, as well as a four-meter-thick concrete wall surrounding the reactor chamber.
Before re-application for permission to assemble the tokamak equipment inside the cryostat, it will be necessary to conduct a new thorough analysis of the design.
bbabo.Net