You must have misunderstood what you were replying to. The GP said that there are test wells around the facility for detecting leaks and they detect at levels much lower than is dangerous.
The post wasn't implying that nuclear power is absolutely safe. Simply that safety measures in place worked in this case and the incident was handled correctly with respect to response and reporting.
I can tell you that many monitoring wells are rarely tested before they're "operational".
Typically they're just installed according to a site model and assumed to function like that.
Happened to koch along the Mississippi where they assured regulators for a decade that you'd never see their contamination. Eventually someone was sampling along the Mississippi and there it was.
The post wasn't implying that nuclear power is absolutely safe. Simply that safety measures in place worked in this case and the incident was handled correctly with respect to response and reporting.