Chalk River Laboratories (CNL) is a Canadian nuclear research facility in Deep River near Chalk River, about 110 mi north-west of Ottawa. The CNL Chalk River site is a federal site that is contaminated with waste that was generated over decades of research and development. In 2014, the CNL was given control over operations at the Chalk River site by the government.
The joke is that it's always five o'clock somewhere, and drinking with breakfast--or at least brunch--is in fashion, especially if it incorporates juice and is suddenly a breakfast drink. Mimosas, screwdrivers and bloody marys have never gone out of style, but now people are actually putting their booze IN their breakfast food.