In the ruling, presiding Judge Takeshi Tachikawa said the Nuclear Regulation Authority "strictly and closely" assessed the two reactors before it found that they meet new safety regulations introduced in the wake of the March 2011 Fukushima nuclear crisis.

The plaintiffs, from Saga and the neighboring prefecture of Fukuoka, had claimed that the safety of the Genkai reactors is not secured.

The No. 3 reactor is now expected to be reactivated this autumn at the earliest.

Disputed in the lawsuit were the way in which possible earthquakes were estimated for aseismic designing for the nuclear plant and the risk of ruptures of aging pipes there.

While the plaintiffs argued that the risk of earthquakes was underestimated, the district court said it found "no unacceptable flaw" in the NRA's assessments.

The court also dismissed as groundless a different earthquake estimate submitted by the plaintiffs that suggested a higher risk of a severe earthquake-triggered accident at the Genkai plant.

The court said that Kyushu Electric has taken measures to prevent pipe ruptures, and that the plant operator carries out the maintenance of pipes in an appropriate manner.

The court did not recognize the possibility of a similar incident to a pipe crack found at the plant's No. 2 reactor in 2007, noting that necessary preventive measures have been taken.

Still, the court added that it was problematic that the pipe crack was not immediately detected.

The ruling triggered an outpouring of anger and disappointment among the plaintiffs who gathered in front of the Saga court.

"I'm filled with anger," said Hatsumi Ishimaru, 65, who leads the plaintiffs group. He criticized the court decision as following the will of the government and the business community.

Katsuhiko Kabuki, chief lawyer for the plaintiffs, blamed the court for neglecting a series of powerful earthquakes in the neighboring prefecture of Kumamoto in April last year. "The ruling is unacceptable," he stressed.

Kyushu Electric issued a statement welcoming the court ruling as "reasonable." It vowed to continue voluntary efforts to improve safety and stability at the Genkai plant.

In January this year, the NRA deemed that the No. 3 and No. 4 reactors meet the safety regulations introduced following the 2011 triple meltdown at Tokyo Electric Power Company Holdings Inc.'s Fukushima No. 1 nuclear plant. In April, Saga Governor Yoshinori Yamaguchi announced his approval for the reactors' restart.

At a press conference in Tokyo on Tuesday, Chief Cabinet Secretary Yoshihide Suga said the government continues to uphold the NRA's assessments. (Jiji Press)