Revised regulations were announced by the NRA in July 2013, which must be met before reactors can receive permission to restart. These set out requirements for plants to be able to respond to a variety of natural phenomena as well as establish new measures to mitigate the effects of severe accidents, such as reactor core damage caused by beyond design basis events. Chugoku applied to the NRA in December 2013 for inspections to verify whether measures taken at Shimane 2 meet the new safety standards.
Chugoku has constructed a 15-metre-high sea wall to protect the plant from tsunamis and made preparations for a potential eruption of the Mount Sanbe volcano. It aims to complete seismic reinforcement and other works for Shimane 2 by the end of March 2022. Chugoku anticipates investing a total JPY600 billion (USD5.5 billion) on safety measures for the Shimane plant as a whole.
On 23 June, the NRA approved a draft report finding that Shimane 2 meets Japan's revised regulatory standards. The assessment of the unit has now been officially adopted after a public comment period and other procedures, clearing the way for it to resume operation.
However, Chugoku is still required to obtain approval from the city of Matsue and Shimane Prefecture before it will be able to restart Shimane 2.
"We will continue to pursue further improvements in the safety of the Shimane Nuclear Power Station, and will continue to make every possible effort to ensure the safety of the power station," Chugoku said in a statement.
Shimane 2 becomes the 17th Japanese reactor to pass the regulator's safety screenings and the fifth BWR - the same type as those at the Fukushima Daiichi plant - to receive regulatory approval to restart.
Shimane unit 1 - a 460 MWe BWR that started commercial operation in March 1974 - is currently being decommissioned. In August 2018, Chugoku initiated the regulatory process for starting up Shimane 3, a new 1373 MWe advanced boiling water reactor nearing completion.