Photo/IllutrationMassive walls are intended to protect Chubu Electric Power Co.’s Hamaoka nuclear plant in Omaezaki, Shizuoka Prefecture, from tsunami. (Asahi Shimbun file photo)

Mandatory steps to respond to possible terrorist attacks and other safety measures will cost 11 nuclear plant operators at least a combined 4.41 trillion yen ($40 billion), according to this year's estimate, an Asahi Shimbun study found.

The soaring outlays undermine a government claim that nuclear energy will be the cheapest source of power in 2030.

What is clear is that costs will increase year by year.

Operators are obliged to strengthen their facilities to withstand a terrorist attack within five years of clearing more stringent regulations on reactor restarts imposed by the Nuclear Regulation Authority.

The new regulations were put in place in the aftermath of the triple meltdown at the Fukushima No. 1 nuclear power plant triggered by the 2011 earthquake and tsunami.

The Asahi Shimbun study covered nine regional utilities, ranging from Hokkaido Electric Power Co. to Kyushu Electric Power Co., as well as Japan Atomic Power Co. and Electric Power Development Co. (J-Power), which is constructing the Oma nuclear power plant in Aomori Prefecture.

Safety measures require operators to strengthen their ability to respond to a major earthquake, tsunami and raging inferno.

Each year, those companies must update their estimates on safety spending.

As of July, their overall total reached 4.41 trillion yen, up 582 billion yen from a year earlier.

The soaring cost is due mainly to NRA insistence that operators seeking to restart their plants implement tougher safety precautions than they had initially envisaged.

The bulk of the increase represents ballooning costs to construct anti-terrorism facilities.

Under the new regulations, operators are obliged to construct a facility that gives them the means to cool reactors via remote control in the event of a terrorist attack or an aircraft smashing into a plant.

Three of the operators divulged their spending on safety upgrades against a terrorist attack in the Asahi Shimbun study. Together, they operate five nuclear plants. Anti-terrorist measures for each reactor averaged 79 billion yen.

Six of the 11 respondents have yet to report on how much they will spend on them.

Total spending by operators on safety measures will likely rise by hundreds of billions of yen when the tab for anti-terrorist measures is included.

Kyushu Electric Power Co. reported 240 billion yen to protect the No. 3 and No. 4 reactors at its Genkai nuclear plant in Saga Prefecture.

That brings Kyushu Electric’s total spending on such safeguards to nearly 1 trillion yen, the highest figure to date among the operators.

Kansai Electric Power Co. set aside 51.7 billion yen on anti-terror measures for the No. 3 reactor at its Mihama nuclear plant in Fukui Prefecture.

The utility’s total safety cost could reach nearly 1 trillion yen as it is required to implement the same measures at its Oi nuclear plant in Fukui Prefecture, where the No. 3 and No. 4 reactors are operating.

Costs released by the operators to date suggest that they expect to spend an average of 180 billion yen per reactor.

The government asserted three years ago that nuclear energy will be the cheapest source of power in 2030, but that now appears to be wishful thinking.

The assertion was based on its study of the cost effectiveness of a range of energy sources and an estimate that safety precautions will cost 100 billion yen per reactor on average.

(This article was written by Toshio Kawada and Yusuke Ogawa.)