Seaglow

A Soviet nuclear submarine, sunk during the Cuban Missile Crisis, lies off the coast of Puerto Rico in 300 meters of water. The wreck's experimental plutonium reactor is now unstable and leaking radiation into the Gulf Stream - radiation that endangers not only Puerto Rico but the entire American Eastern seaboard.
A Deadly Prize

The Russian Federation hires Al Madeira to recover the reactor and Madeira soon learns that he's not the only interested party. Soon he's caught in a vise between the U.S. and Russian intelligence agencies, the Russian mob and Saddam Hussein.