8 Juillet 2013
July 8, 2013
What utilities have to do under new nuclear rules
Japan's new nuclear safety guidelines are the first to oblige power companies to prepare for major nuclear accidents. They also demand that utilities make their assessments for possible earthquakes and tsunami stricter than in the past.
The rules require utilities to set up an emergency command center that can withstand earthquakes and radiation. They also call for the installation of filter vents for boiling water reactors -- the kinds used at the stricken Fukushima Daiichi plant. The vents are designed to release pressure in containment vessels while limiting massive emission of radioactive substances.
Utilities will also have to replace power cables with non-flammable types before resumption of operations.
Plant operators also need to have ways to cool nuclear fuel from outside the reactors in case of terrorist attacks from aircraft.
A facility housing a back-up central control room must be set up 100 meters from reactors within 5 years.
The guidelines say faults that moved in the last 120,000 to 130,000 years are judged to be active faults.
But if it is impossible to make clear assessments, the guidelines say judgment should be based on whether faults moved in the last 400,000 years. Three-dimensional stratal analysis is also required.
Power firms are asked to anticipate the largest possible tsunami, and set up seawalls and take other measures to prevent water from entering buildings.
They must also assess anticipated damage from volcanic eruptions and tornados.
Nine of the pressurized water-type reactors in the country use flammable electric cables. It is believed that replacing them will cost an enormous amount of time and money. That is also true for other upgrades required of operators running aged reactors. The stricter safety standards are expected to force companies to decide which reactors to keep and which to decommission.
Screening plants to restart nuclear reactors
Japan's nuclear authority will soon begin screening applications from power companies to restart some nuclear reactors.
Screening will be based on new nuclear safety guidelines that took effect on Monday.
The Nuclear Regulation Authority will assign 80 people in 3 teams to do the work.
Officials from the nuclear agency say it will take at least 6 months to process an application from each plant.
Items to be examined include operators' preparation for serious accidents, powerful earthquakes and tsunami.
The agency will also perform onsite inspections.
The central government will approve the restart of reactors at plants found safe by the nuclear authority.
But before the final go-ahead, the government and power companies must gain the consent of local municipalities.
Some of the local governments have no plans in place for evacuating residents in case of an accident.
The nuclear authority says the municipalities must submit such plans before it can give the green light to restart reactors.
It is not known how long the government will take to approve the restart.
Two reactors at the Ohi plant in Fukui Prefecture are the only ones in the country currently online. Once they are idled for regular inspection in September, no nuclear reactors will be operating in Japan.