Due to stricter government safety regulations, 30 of Japan’s idled 48 nuclear reactors have no immediate prospects of restarting operations, at least in the near future, according to an Asahi Shimbun survey of utilities.

Thirteen of those, mainly due to their age, are having particular difficulty in complying with the new standards, according to the survey, and are likely to be decommissioned.

The government tightened safety regulations for the nation’s nuclear power plants in the wake of the accident at the Fukushima No. 1 nuclear power plant, triggered by the 2011 Great East Japan Earthquake and tsunami.

The new restrictions ban electric power companies from locating reactor facilities directly on top of active fault lines. The state also revised the Law on the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors to limit, in principle, the operational life of reactors to 40 years.

“No matter how much money and time we spend, it would be impossible (for some reactors to clear certain hurdles),” said an official with an electric power company, referring to the two requirements.

The two restrictions are the main obstacles the utilities face in their efforts to restart idle reactors.

The 13 likely to be decommissioned are the Tokai No. 2 plant in Ibaraki Prefecture; the three reactors at the Mihama plant in Fukui Prefecture; the two reactors each at the Oi, Takahama and Tsuruga plants, all in Fukui Prefecture; the No. 1 reactor at the Shimane plant; the No. 1 reactor at the Ikata plant in Ehime Prefecture; and the No. 1 reactor of the Genkai plant in Saga Prefecture.

Of these reactors, the Tsuruga plant’s No. 1 reactor and the Mihama plant’s No. 1 and No. 2 reactors have exceeded the 40-year limit.

The Shimane plant’s No. 1 reactor will mark its 40th anniversary of operation at the end of this month, while the Takahama plant’s No. 1 reactor will pass the four decade mark in November.

Furthermore, an investigation by the Nuclear Regulation Authority has concluded that there is an active fault line beneath the Tsuruga plant’s No. 2 reactor building. A slip of an active fault directly under a reactor is highly likely to lead to its destruction.

The NRA is also studying the geological structure of the ground beneath the Shika nuclear plant in Ishikawa Prefecture, the Higashidori plant in Aomori Prefecture and the Mihama plant.

The new government standards also require nuclear plant operators to bolster fire prevention measures.

It is also unclear whether the four reactors at the Fukushima No. 2 plant, located 12 kilometers south of the crippled No. 1 plant, will be allowed to resume operations.

Fukushima Prefecture and local municipalities that are home to the Fukushima No. 2 plant have demanded all the reactors there be decommissioned. That makes it difficult for the plant’s operator, Tokyo Electric Power Co., to bring those reactors back online.

Utilities operating the remaining reactors among the 30 have said they have yet to decide when they can apply for safety screenings to restart their reactors. They say it would take much time to complete work needed to meet the new safety requirements demanded by the government.

The companies also said they will place priority on bringing back online those reactors that can more easily be brought up to standard.

To date, the NRA has received applications to restart 17 reactors at 10 nuclear plants. Ten of those reactors–the No. 3 reactor at the Tomari plant in Hokkaido, the Oi plant’s No. 3 and No. 4 reactors, Takahama’s No. 3 and No. 4 reactors, Ikata’s No. 3 reactor, the Genkai plant’s No. 3 and No. 4 reactors and the No. 1 and No. 2 reactors at the Sendai plant in Kagoshima Prefecture–are currently undergoing screening as originally scheduled.

But the NRA’s inspection process is behind schedule for the remaining seven reactors: the Tomari No. 1 and No. 2 reactors; the No. 2 reactor of the Onagawa plant in Miyagi Prefecture; the No. 6 and No. 7 reactors at the Kashiwazaki-Kariwa plant in Niigata Prefecture; the No. 4 reactor at the Hamaoka plant in Shizuoka Prefecture; and the Shimane plant’s No. 2 reactor.

Although the operator of the Hamaoka plant plans to apply for safety checks to resume operations at the facility’s No. 3 reactor by the end of fiscal 2014, the problem is that the facility sits in a location along the Nankai Trough southwest of Tokyo, where it has long been predicted a major earthquake will occur.

Then Prime Minister Naoto Kan ordered the operator of that plant to suspend all its reactors in May 2011 as the Fukushima nuclear crisis was unfurling.

But in the process of suspending operations there, a steam condenser for the No. 5 reactor was damaged, resulting in an influx of large amounts of seawater. Rust has also been found in a pressure vessel at the plant as well.