Problem of the Week

Chapter 11: Energy and Its Conservation

Problem of the Week

Nuclear Navies
Put to sea in 1955, the USS Nautilus became the first nuclear-powered submarine. At the end of the Cold War, in 1989, there were over 400 fission-driven submarines. Presently, there are fewer than 200 such submarines active. Russia and USA have a few surface nuclear ships including carriers, cruisers, and icebreakers.

There are six nuclear submarines that now lie abandoned on the ocean floor: two American and four Soviet.

Akula Class
Thirteen Akula class submarines are active on the world's seas, six in the Northern Fleet and seven in the Pacific Fleet. A 190-MW nuclear reactor powers an Akula, generating a propeller power of 43 000 hp. During the 1980s, the Akula class was one of the quietest and quickest submarines in the world.

Calculate the efficiency of the nuclear reactor to transform nuclear energy into propulsion.

Assume that energy transformation from propulsion to motion is a 100% efficient, calculate the time required for the submarine to attain 35 knots. Where might most of the energy be "lost"?