Experts working for the €20bn International Thermonuclear Experimental Reactor (Iter) nuclear fusion project are “vigorously preparing” additional information and analysis requested by France’s nuclear regulator ASN (Autorité de sûreté nucléaire) with the goal of providing key answers during the second quarter of 2022, Gilles Perrier, head of Iter’s safety and quality department said.

In an article posted on the Iter Organisation website, Mr Perrier addressed the decision by ASN to delay the anticipated February 1 lifting of a preset tokamak assembly “hold point”.

ASN has requested clarifications and information from Iter Organisation staff, including additional modelling and analysis on specific safety related issues. Following receipt of the material, ASN will permit welding of the first sections of the vacuum vessel for what is planned as the world’s largest magnetic confinement fusion device.