Stabilizing the reactors would allow workers to start dismantling and decontaminating the site, a process which experts have said will take at least a decade.
The new simulation may call into question the efforts to cool and stabilize the reactor, but the Tokyo Electric Power Company, or Tepco, says it is not worried more than eight months after the accident.
Increasing the system pressure also tends to stabilize the reactor.
To stabilize the reactors and restart cooling systems, the company rushed to reconnect the power plant to the electric grid.
The Tokyo Electric Power Company, which runs the plant, said it hoped to connect the electric cord to the cooling equipment inside the facility later Saturday in an attempt to stabilize the reactors that were damaged by the powerful earthquake and tsunami that struck Japan eight days ago.
With the drumbeat of bad news, including another powerful aftershock on Thursday, it will take months, if not years, to stabilize the reactors and spent fuel pools that were damaged in last month's earthquake and tsunami at the Fukushima Daiichi plant.
Arguably, since officials were unable to stabilize the reactors in the weeks following the tsunami, the danger increased as radiation leaks and explosions continued.
The easing has become possible because of success in stabilizing the three reactors at the plant that melted down after the magnitude-9 earthquake and huge tsunami on March 11, according to the Nuclear Emergency Response Headquarters.
There is no question that the Fukushima plant is less dangerous than it was during the desperate first months after the accident, mostly through the determined efforts of workers who have stabilized the melted reactor cores, which are cooler and less dangerous than they once were.
Workers sought to cool and stabilize the damaged reactors by pumping seawater and boric acid into them.
