OHI, Japan (AP) ― Experts from the International Atomic Energy Agency on Thursday began their first inspection of a Japanese nuclear power plant that has undergone official “stress tests’’ ― a key step required to restart dozens of nuclear plants idled in the wake of the Fukushima crisis.

A 10-member IAEA team was inspecting the No. 3 and No. 4 reactors at the Ohi nuclear power plant in Fukui, western Japan, where there is a string of reactors.

“We look forward to seeing the types of specifications and types of improvements that Kansai Electric Power Co. has made at the Ohi nuclear plant,’’ mission leader James Lyons said at the outset of the plant visit. “Because that would give us opportunity to see how nuclear utilities are responding to these instructions.’’

The inspection comes a week after Japanese nuclear safety officials gave preliminary approval on the Ohi reactors, a step closer to restarting them.

Authorities have required all reactors to undergo stress tests in the wake of Fukushima nuclear crisis and make necessary modifications to improve safety. The stress tests, similar to those used in France and elsewhere in Europe, are designed to assess how well the plants can withstand earthquakes, tsunamis, storms, loss of power and other crises. Another hurdle will be gaining local approval for the plants to restart, required after regular 13-month inspections.

Only four of Japan’s 54 reactors are currently operating, and if no idled plants get approval to go back on line, the country will be without an operating reactor by the end of April.

Public concerns about the safety of nuclear power have grown after the March 11 earthquake and tsunami knocked out the vital cooling system at the Fukushima Dai-ichi nuclear power plant, sending three of its reactors to meltdowns and releasing massive radiation into the environment.

Prime Minister Yoshihiko Noda has promised to reduce Japan’s reliance on nuclear power over time and plans to lay out a new energy policy by the summer. But the nation obtained about 30 percent of its electricity from nuclear power before the crisis, and it could face power shortages if it cannot get more nuclear plants back on line soon.

Some experts have been critical of the stress tests, saying they are meaningless because they have no clear criteria. They also say that the government’s simulations of crises based on a single event are not realistic because disasters often occur in a string of events.