CARENTAN, France - When the Chernobyl catastrophe spewed a radioactive plume across Europe in 1986, the pro-nuclear French government said, in so many words, that the toxic cloud had neatly swerved around France.

 Now, 15 years later, even in France, the days of public trust in all things nuclear are gone, French environmentalists are saying as they protest foreign nuclear waste shipments into France.

 ''There's been an evolution in French thinking,'' Jean-Luc Verret, regional secretary for lower Normandy's Green

Party, said last week as a train bearing nine 110-ton casks of spent fuel elements approached Carentan, an upper Normandy town not far from the Allied landing sites.

 ''They pretended Chernobyl didn't affect France - they can't do that any more,'' Verret said.

 Indeed, even here near a giant commercial radioactive waste plant at La Hague, on a wind-swept tip of Normandy, wisps of doubt about nuclear safety have surfaced in recent years.

 On Thursday, French environmentalists delayed a rail convoy of German nuclear waste bound for the plant at La Hague.

Rail shipments of waste to the plant resumed this spring after a three-year hiatus caused by the discovery of widespread radioactive contamination of rail cars.

 The delays, caused by Greenpeace and Green activists, followed charges by a train workers' union that there is a ''lack of transparency'' and too little public information about spent nuclear fuel rail transports to La Hague.

 In addition, another environmental group, Manche Nature, has petitioned a Cherbourg judge to stop foreign nuclear waste shipments to the vast La Hague plant.

 The argument was that they are illegal. French law forbids storing foreign waste, Didier Anger, representative for the Greens, said last week.

 Also turning up the heat last week was an independent radiation testing laboratory in nearby Caen. The lab said a radiation leak in May from the plant at La Hague had been much worse than the company had acknowledged.

 A government radiation monitoring agency, the Nuclear Protection and Surveillance Institute, confirmed that its instruments had detected the leak in Alencon, more than 60 miles away.

 And the independent testing lab, the Western Radioactivity Verification Association, said health studies based on the company's own figures should be revised.

 ''Are we in the presence of chronically poor calibration? That would mean a good part of the studies done around the plant would be cast into doubt since they were based on the company's figures,'' said Pierre Barbey, the lab's scientific adviser.

 Environmentalists pay much attention to La Hague because France, which relies on reactors for 80 percent of its energy, has cast itself as a global leader in nuclear power and waste.

 In addition, money is involved from abroad, though figures are not forthcoming. La Hague is the world's largest commercial facility to separate plutonium and uranium from spent nuclear fuel.

 And as world interest in nuclear waste disposal mounts, France is exporting its expertise.  The United States and France, for example, have agreed to do joint research on nuclear waste, among other issues.

 But there are problems close to home. Last week, a group of Norman mothers said a new leukemia study adds to their worries about the health effects of the Cogema nuclear waste plant's radioactive discharges on their children.

 One group, called Les Meres en Colere (The Angry Mothers), was formed in 1997 when a noted epidemiologist suggested a link between a slight rise in leukemia cases in children playing on local beaches and eating local fish and shellfish near La Hague.

 Published on Jan. 11, 1997 in the British Medical Journal, the study, by Jean-Francois Viel, epidemiologist at the University of Besancon in eastern France, far from La Hague, suggested a connection between the reprocessing facility's radioactive emissions and the ailment in local children.

 Viel's was the first case-control study conducted around a nuclear installation in France. It provoked furious controversy across France, and Viel was widely vilified.

 But this summer, French newspapers declared Viel, whose nickname became the ''nuclear pariah,'' vindicated when a more recent government study, published in the British Medical Association's Journal of Epidemiology and Community Health, confirmed Viel's finding of a leukemia cluster near La Hague.

 The operator of La Hague, a government-subsidized corporation called Cogema, says its activities are safe and carefully monitored. In a statement, the company acknowledged concern but said, ''In the past 20 years, scientifically founded studies indicate no link between operations at the Cogema-La Hague site and the probability of occurence of infantile leukemia.''

 The Angry Mothers spokeswoman, Nathalie Bonnemains-Geismar doesn't buy it.

 She says her concerns are backed by ''the population's growing anxiety about the health effects of all reprocessing activities at La Hague and its liquid and gaseous radioactive releases.''

 On Thursday, as the nuclear waste train approached Carentan, it stopped for a Greenpeace activist who had barred its way by straddling one of the train rails rail, his hands stuck inside a steel tube nestled under the rail.

 ''Reprocessing is an economic and environmental aberration,'' declared a Cherbourg shipyard worker, Philippe Rousselet, as police pried him loose.

 The train moved on as a police helicopter hovered overhead.

 This story ran on page A29 of the Boston Globe on 8/5/2001.
 © Copyright 2001 Globe Newspaper Company.