A research reactor near Munich has emitted excess C-14 radiation, says the Bavarian city's technical university. The "slight" leak late March had shown up Thursday when monthly readings were collated.
Munich's technical university (TUM) said Saturday a neutron reactor located at Garchingjust north of the metropole was found to have leaked nuclides into the atmosphere "slightly" above the level permitted annually in its license.
Neither human beings nor the surrounding environment had been endangered, said the TUM and Bavaria's environmental ministry — responsible for oversight.
Monthly figures collated on Thursday had shown an excess in C-14 particles 15% above the permitted yearly level, with the potential to cause "theoretically" a load for the public of 3 Mikrosieverts at the maximum.
That was less than the level a patient undergoing an x-ray at the dentists' would endure, said Anke Görg spokesperson for the TUM's operating institute, known as FRMII.
"An individual error during the installation of the mobile drying unit used for this purpose caused the discharge of the C-14 over a short period of time," Görg added, referring to a method used to extract C-14 in resin from water in the reactor's tank.
The Munich-based Süddeutsche Zeitung newspaper said the notifiable incident was ranked "0," very low on the international scale.
Garching's special campus, where an "egg"-shaped dome covers an older reactor — used between 1957 and 2000 — draws annually about 1,000 international researchers who experiment with its newer neutron reactor, the so-called FRMII.
The facility was put on hold on March 17 because of the current pandemic, leaving many scientists unable to glean results for industry and medicine, said Görg.
The FRMII reactor, inaugurated in 2005, remains controversial among organizations like Germany's branch of Friends of the Earth (BUND) and opposition Greens in Bavaria's state assembly.
Detection of the isotope C-14 is a key method in so-called carbon-dating to determine the age of ancient objects containing organic material.
Bavaria, which in the 1970s went through political turmoil over the siting of six nuclear reactors, now has only two of them in operation — Isar 2 east of Munich, and Gundremmingen C, west of Augsburg.
As a whole, Germany currently has six reactors running as a whole, according to the federal environment ministry, as it continues its nuclear-power phase-out, spurred by Japan's 2011 Fukushima disaster, as it pushes for renewables.