China’s ambitions to be a leader in nuclear technology have been dealt a fresh blow, as construction of its most advanced reactor is facing a new delay. The project—which China is developing with Westinghouse Electric Co. of the U.S.—faces new development problems and now isn’t expected to start up until 2016 at the earliest, the chief engineer at China’s state-owned reactor technology company said Thursday. “We discovered some new problems during tests so we need to delay it more until next year,” Wang Zhongtang, chief engineer of China’s State Nuclear Power Technology Corp., said on the sidelines of an industry conference. Mr. Wang didn’t specify the nature of the latest problems found at ongoing trials for the reactor, nor did he provide a more precise time frame for its launch. The delay is the second for the project, which had been slated to start by the end of 2013. […]