Ohma start-up delayed by a further two years

05 September 2018

Completion of the Ohma nuclear power plant, under construction in Japan's Aomori prefecture, will be delayed by a further two years owing to the regulator's ongoing review of enhanced safety measures at the plant.

The Ohma 1 construction site (Image: J-Power)

In December 2014, Japan Electric Power Development Corp (J-Power) submitted an application to the Nuclear Regulation Authority (NRA) to make changes to Ohma 1's reactor installation to strengthen the unit's protection. These measures - including tsunami countermeasures, ensuring power supplies, ensuring heat removal functions, and severe accident responses - were originally expected to be completed by the end of 2020.

However, in September 2015, the company announced a delay to the start of safety equipment construction, pushing back the start of operation to around 2021. This delay was attributed to the prolonged screening process by the NRA after the company was requested to submit additional information about its plans.

A year later, J-Power said it expected a further delay of around two years in the completion of the NRA's review and approval process for Ohma 1. At that time, it expected construction of the safety upgrades to begin in 2016 and to be completed in the second half of fiscal year 2023.

J-Power announced yesterday that the NRA's review was still under way.

"Although items are examined in parallel and [there has been] some progress, it is expected that it will take a reasonable amount of time in the future, and based on the fact that the plant-related examination will follow, we will have to expect about two more years," the company said.

It added, "Along with this, based on the assumption of the review and approval period, the start of safety enhancement countermeasure construction is expected to be in the second half of 2020 and the end is expected to be the latter half of 2025." J-Power noted the start of operation of Ohma 1 "is still unknown".

The start of construction of the Ohma plant was originally due in August 2007, with commercial operation planned for March 2012. However, the imposition of more stringent seismic regulations put back the start of construction to May 2008 and commercial operation to November 2014.

Work to build the first unit at Ohma - a 1383 MWe Advanced Boiling Water Reactor - was about 40% complete in March 2011 when a tsunami caused the accident at the Fukushima Daiichi plant. Construction of Ohma 1 was suspended following the accident, but was resumed in October 2012. At that time, J-Power said it would strive to establish a safe power plant by, among other things, ensuring reinforced safety measures are implemented that take into account the lessons learned from the Fukushima accident.

Researched and written by World Nuclear News