The ITER organization informsthat the regulator suspended work on the assembly of a thermonuclear reactor. The French organization for nuclear safety Nuclear Safety Authority (ASN) there are still a number of questions on the safety of the project, to which ITER (as an organization) has not yet given answers. It is expected that the suspension of installation work at the facility will not affect the overall schedule for the construction of the reactor.
Image Source: ITER
Since the work is being carried out in France, the French regulator is responsible for the safety of the nuclear facility. A fusion reactor project in southern France was approved by ASN in 2012. In the process of construction and installation of facilities and equipment, ITER is obliged to provide the regulator with comprehensive information on safety at all predetermined stages of work. One of these ITER control points was supposed to pass on February 1, but the report was submitted in an incomplete volume. Therefore, on January 25, ASN reported that it was impossible to continue work on assembling the reactor without additional clarifications from ITER.
A breakpoint or “hold point” that has not been fully validated was set by the regulator in November 2013. When it was reached, it was possible to start welding the first two sections of the vacuum chamber in the tokamak shaft, which made the process of assembling the reactor irreversible. But to start the process, it was necessary to confirm the safety of the B2 foundation slab under the reactor building, and this foundation is 120 meters long, 80 meters wide and over 1.5 meters thick, as well as prepare some other reports.
ITER was required to demonstrate the safety of Slab B2 during the construction process. The organization also had to provide radiological maps in the reactor operation area. These maps would help to ensure the safety of personnel on the site without the use of special radiation protection equipment following the start of the reactor operation. Structural elements and equipment by themselves must create a sufficient shielding effect.
ASN also asked for additional analysis before starting the welding process of the vacuum chamber, as some dimensional discrepancies were found at the junction between the two sectors of the vacuum chamber. This is necessary to correct the program before starting the automatic welding machine.
The first section of the chamber is already assembled, including the installation of a thermal shield and two toroidal field coils. It will be transferred to the reactor shaft in the coming weeks. The second section, which will be welded to the first in the shaft, will be assembled over the next few months. There are 9 such sectors in total: 5 are made in the EU, and 3 produced and completed last 4th South Korea.
ITER expects that the suspension of work on the assembly of the reactor will not affect the overall work time. The first plasma in the reactor is expected to be received in 2025. But before the experiments on the synthesis of deuterium and tritium, things will come only by 2035. The ITER reactor is not designed to generate electricity. It should confirm the possibility of a thermonuclear reaction with a positive yield. So, with the cost of igniting a plasma of 50 MW at the output, scientists expect up to 500 MW of energy, and the reactor should hold this power for regarding 400 seconds.
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