Japan’s largest nuclear complex, Kashiwazaki- Kariwa, looks set to remain off line for the immediate future while regulators and operators Tokyo Electric Power Co (Tepco) attempt to assess the extent of any damage and long-term safety of the reactor complex, damaged by a recent earthquake.

Recently revised Japanese seismic safety design guidelines will require Tepco to demonstrate that an earthquake of magnitude 6.6 on the Richter scale has been included in predictive models.

Comments attributed to Japan’s Nuclear & Industrial Safety Agency (NISA), the Nuclear Safety Commission (NSC) and a task force investigating safety at the site suggest it may be more than one year, and perhaps as long as two years before the units can restart.

Tepco is expected to argue in favour of an early restart for those reactors which were less affected by the earthquake.