Japan's nuclear allergy

Yokosuka, Japan, site of a United States Navy base, is treating the 2008 decommissioning of the USS Kitty Hawk and its planned replacement with a nuclear-powered aircraft carrier as a major issue in its current mayoral campaign. While all four candidates oppose a nuclear-powered carrier, none have actually come up with a way to keep one from being assigned to the base. (The typical strategy so far seems to be to petition Tokyo.)

Opposition to the nuclear carrier seems rooted in the nation's deep aversion to all things nuclear. Asahi provides this example of justification for the opinion that nuclear vessels are dangerous:

In July 1998, a U.S. nuclear-powered submarine called at Yokosuka and city officials said they detected abnormally high radioactivity in the water.

This sounds to me like the same pseudoscience fueling the campaign against the use of depleted uranium rounds, but I could be mistaken. Does anyone know if radiation has ever been shown to be higher in the waters around nuclear vessels?