But one category of reactor has been delayed by the Fukushima incident. At reactors that had been approved before the Fukushima accident but where construction had not yet begun, the government still has not allowed construction to start while continuing to study whether further safety improvements can be made, said Xu Yuanhui, one of China’s top nuclear engineers for the past half century.

The delay applies to several conventional nuclear reactors plus Beijing’s project to build two reactors in northeastern China, using a new generation of technology known as a pebble-bed design. Critics and advocates describe it as safer than current reactors, though its cost-effectiveness unclear.

The two reactors in Shidao, in Shandong Province in northeast China, were approved days before the Fukushima nuclear accident began with an earthquake and tsunami March 11. But the 50-month timetable for building them cannot start until the government lifts its hold on construction.

“By the end of this year, maybe we’ll have some information from the government side,” Dr. Xu said.

Nuclear power represented only 1.1 percent of China’s electricity generation capacity at the end of last year. With wind turbines and coal-fired power plants being installed at rates that far surpass those in any other country, nuclear power is on track to account for no more than 4 percent of electricity capacity by 2015.

A big part of the appeal of nuclear energy for Chinese officials is that it supplies baseload power, meaning it is available 24 hours a day and seven days a week to meet needs. China passed the United States last year as the world’s largest installer of wind turbines, but wind still accounts for only 3.2 percent of China’s installed electricity generation capacity and less than 2 percent of electricity generated.

Coal remains by far the dominant source of electricity in China, producing three-quarters of the country’s electricity. Nuclear power mainly displaces coal as a source of baseload power. That has also made it popular with Chinese officials, as they have set increasingly ambitious targets to slow the country’s rapid rise in emissions of global warming gases, in which the country already leads the world.

Until reliable, large-scale storage of electricity is perfected for renewable energy sources like the wind and sun, “they’ve got to continue using nuclear as a fundamental part of their fuel mix,” said James A. Maguire, the regional managing director for Asian infrastructure at Aon Risk Solutions, a risk management and insurance broker.