Hokkaido Electric Power has set the construction cost of the seawall at its Tomari nuclear plant at ¥125.5bn, closing out a figure it had left open for more than two months. The company's disclosure dated October 9, 2026 also keeps completion at August 2027.
What was settled
On July 30, 2026, the company disclosed that the seawall would be finished in August 2027 and said the change in construction cost was still under review. Its latest disclosure says that review is complete and the new cost is ¥125.5bn. It says nothing other than the cost has changed from the earlier announcement.
The disclosure does not give the earlier cost, so the size of any increase cannot be read from it.
What is being built
The company says it fixed the basic structure at a Nuclear Regulation Authority review meeting on conformity with the new regulatory standards in February 2024, where it explained the design policy and structural feasibility results. Work began on March 28, 2024.
The new wall stands 19.0 metres above sea level, against a site elevation of 10.0 metres. It runs about 1,200 metres, is up to 30 metres wide, and is built of concrete and cement-improved soil. It rests directly on bedrock, which the company calls a rock-seated support structure.
The schedule squeeze
The company describes a cramped work area inside the plant grounds, where the seawall work has collided with other safety-measure construction. It says it has taken various steps to shorten the schedule to hold the August 2027 finish, and that it will look for further cuts to finish sooner.
What remains open
The company says it will promptly disclose any matters that emerge, including effects on earnings. The notice gives no earnings figure. It is also a construction notice: it sets no restart date for the reactors and records no regulatory approval.