For the Chinese Communist party, opacity is a virtue and transparency a vice. This approach to governance has worked well for the party, which will celebrate the centenary of its founding on Thursday.

Unfortunately, it does not work so well when you are running a Chinese nuclear power plant, especially in partnership with a foreign investor that cannot so readily embrace party principles.

China General Nuclear Power Group and Framatome, a unit of France’s EDF, provided a textbook example of this two weeks ago, when CNN reported that President Joe Biden’s administration was “assessing [a] reported leak at Chinese nuclear power facility”.

The alarming headline encapsulated what must be one of President Xi Jinping’s worst nightmares.

In January last year, the party’s initial struggle to control the Covid-19 outbreak caused many to wonder if it was finally meeting its “Chernobyl moment” — a system failure that would fatally undermine the regime’s credibility, much as the 1986 Chernobyl nuclear power plant disaster did for the Soviet Communist party.

Xi’s administration recovered from its initial pandemic missteps, so much so that the party now touts China’s successful containment of coronavirus as one of its greatest triumphs. But imagine if, just two weeks before the party’s 100th birthday party, there had been a Chernobyl or Fukushima-scale nuclear disaster just 75km west of the Pearl River delta, one of the country’s most densely populated and economically vibrant regions.

According to CNN’s report, based in part on documents provided by Framatome to the Biden administration, the leak had occurred at the Taishan Nuclear Power Plant in southern Guangdong province. Although administration officials did not think a major disaster was imminent, the documents also said China’s nuclear regulator had raised the plant’s radiation emission limits to help it deal with the situation.

Because CGN is one of dozens of Chinese companies that have been formally sanctioned by the US, Framatome potentially needed the Biden administration’s approval before helping its Chinese partner deal with the situation. CGN and EDF are 70-30 joint venture partners at Taishan.

Framatome’s memo to the US energy department was dated June 8, and CNN’s report came out during the morning of Monday June 14, China-time. The Taishan plant had apparently tried to pre-empt the report by publishing a statement on its website on Sunday night on June 13. That statement, however, simply said there were no problems at the plant and did not address any of the seemingly alarming details in CNN’s report.

CGN and Taishan’s “never apologise, never explain” type of approach to the situation rattled people’s nerves. One local government official in Jiangmen, whose jurisdiction includes the Taishan plant, told the Financial Times that local residents were completely in the dark. “The plant says everything is fine,” the official said. “Without proper explanation of CNN’s report, what can we do?”

Unlike its Chinese partner, Framatome and EDF could not stay silent. Their position was further complicated by the fact that the Taishan plant is the first in the world to operate a European Pressurised Reactor, a Franco-German technology. Any serious problems at Taishan could have enormous implications at other EPR projects, such EDF and CGN’s UK joint venture, now under construction at Hinkley Point.

But subsequent statements and briefings by the two French companies were still far less detailed than the information provided to the Biden administration. They said what was happening at Taishan appeared to be linked to damaged fuel rods — a common occurrence at nuclear plants that can usually be fixed without having to shut down the affected plant.

“Based on the information right now, I don’t think there’s need for undue concern,” Jeffrey Merrifield, a partner at Pillsbury and former member of the US Nuclear Regulatory Commission, said after the French briefings. “But the lack of information about the event is not helping provide greater confidence that there is not an issue.”

On June 16, more than 48 hours after the original CNN report, the Chinese government indeed confirmed that just five of some 60,000 rods at the affected reactor in Taishan had been damaged — too few to trigger safety concerns. If Beijing had simply said as much in a more timely fashion, this minor incident would never have threatened to become a major story.