Takahama units cleared for extended operation

The Japanese nuclear regulator has today approved the operation of units 1 and 2 of Kansai Electric Power Company's Takahama nuclear power plant for up to 60 years. They become the first Japanese units to be granted a licence extension beyond 40 years under revised regulations.

The Japanese nuclear regulator has today approved the operation of units 1 and 2 of Kansai Electric Power Company's Takahama nuclear power plant for up to 60 years. They become the first Japanese units to be granted a licence extension beyond 40 years under revised regulations.

Kansai's Takahama plant (Image: NRA)

Previously, operating licences lasted for 40 years, subject to a review every ten years. During that period the regulator checked the operator's maintenance plan for the unit.

The Nuclear Regulation Authority (NRA) approved a ten-year operating extension for unit 1 of the Takahama plant in Fukui prefecture in November 2014. The 780 MWe (net) pressurized water reactor (PWR) began operating in November 1974. Takahama 2 - also a 780 MWe PWR - was granted a ten-year life extension in April 2015. That unit started up a year after unit 1.

However, under revised regulations which came into force in July 2013, reactors have a nominal operating period of 40 years. Extensions can be granted once only and limited to a maximum of 20 years, contingent on exacting safety requirements.

Kansai applied to the NRA in April 2015 to extend the operation of the Takahama 1 and 2 reactor by 20 years under the new regulations.

As part of its application, special inspections were conducted, including ultrasound tests on the reactor vessels' welds and eddy current tests on the primary coolant nozzles to identify degradation. The units' containment vessels and their concrete barriers were also inspected for cracks.

Kansai was also required to submit to the regulator a long-term maintenance management policy, as well as implement an aging technology evaluation.

At a meeting today, the NRA approved Kansai's licence extension application.

Takahama 1 and 2 are progressing through the restart process. In April, the NRA confirmed the units meet new safety regulations. The units are the oldest of the seven reactors so far deemed to conform to the new safety standards.

Researched and written
by World Nuclear News