Paris, Sha'ban 26 ,1436,June 13 ,2015, SPA -- France's nuclear watchdog said that a recent shutdown at the Cattenom nuclear power plant did not cause a leak in radioactivity but warned that it could have had the potential to become "major issue." A cooling valve that was blocked open in the first of four reactors, allowing steam to escape and causing a drop in pressure in a generator, triggered the emergency shutdown at the power plant near the borders of Luxembourg and Germany, according to dpa. Nuclear watchdog ASN said in a report that it measured no increase in radioactivity either at the site of the plant or in the surrounding environment. It added that the pressure drop could have damaged the internal workings of the generator. Plant operator EDF said at the time of the shutdown, which occurred on May 28, that the emergency procedure had been a precaution. It added that the event had not posed a risk to the population or the environment. But ASN also warned that in the case of a steam generator tube rupture, "radioactive contamination of the reactor coolant system can then be released into the environment." It traced the malfunction to a recently-replaced faulty valve positioner, prompting ASN to question the reliability of the device. In its report, ASN rated the event the lowest on it 7-point scale, and told EDF to conduct a thorough check on both the reactor and the valve reliability before re-starting. The report caused a stir in Germany, which has long been opposed to France's nuclear power plants along its northern border. The environment minister for the bordering German state of Saarland condemned the threat posed by the plant. --SPA 14:41 LOCAL TIME 11:41 GMT www.spa.gov.sa/w