Workers with plant operator FirstEnergy identified a leak on a feed water Venturi meter. Samples were taken and there was a positive result for tritium in the under drain system in the auxiliary building, according to an event notification report from the U.S. Nuclear Regulatory Commission (NRC).
The sample, obtained January 20, indicated a level of 46,000 picocuries (pCi/l) per liter. The Environmental Protection Agency's limit for tritium in groundwater is 20,000 pCi/l , according to the NRC report.
Tritium occurs naturally in the environment in very low concentrations, but is also produced during nuclear weapons explosions, as a byproduct in reactors producing electricity and in special production reactors where the isotope lithium-6 is bombarded to produce tritium.
The Perry nuclear power plant is located on a 1,100-acre site on Lake Erie, 40 miles northeast of Cleveland.