(Monticello, MN) — Low levels of a radioactive isotope have been found near a Minnesota nuclear power plant. Trace amounts of the isotope, called tritium, were detected in groundwater close to the Mississippi River near the Xcel Energy Monticello Nuclear Generating Plant. However, experts say the levels of tritium found are well below unsafe limits, adding there is no risk to the public. However, Xcel Energy president Chris Clark says they will still work with state and federal officials for a thorough cleanup of the site.