Madrid - Nearly 800 Spaniards will undergo health checks to make sure they have not been affected by radioactive material leaked from the nuclear plant of Asco I in the country's north-east in November, press reports said Tuesday.

Nearly 580 people have already been examined without finding any evidence of health damage.

The checks would nevertheless continue to confirm that nobody had been affected by radioactivity to a significant extent, the Nuclear Safety Council (CSN) said.

The director of a school in the city of Gerona however said Tuesday that he would request health checks for about 40 pupils who visited the plant on April 4.

The CSN accuses the nuclear plant near Tarragona, which is owned by the energy company Endesa, of having downplayed the seriousness of the leak when informing the watchdog about it in April.

The plant also faces sanctions for "inadequate control of radioactive material" because of the leak, which occurred during refuelling.

The environmental group Greenpeace called for the "preventative paralyzation" of the Asco I plant after the incident, which was described as one of the most serious related to nuclear energy in Spain.