WASHINGTON— In his blueprint for a stronger Navy, the sea service’s new top boss, Admiral John M. Richardson, is blunt about what he thinks matters most: nuclear punch.

Battling terrorists is today’s problem, but in looking toward a farther horizon, Richardson wants a Navy built to counter unpredictable future threats from other countries. Tops on his list is a new fleet of nuclear-armed submarines, known as ‘‘boomers,’’ that prowl the oceans as the quiet centerpiece of the nation’s nuclear force. The Navy plans to replace the current fleet of 14 Ohio-class boomers, which began service as early as 1981, with 12 next-generation subs.

‘‘This is foundational to our survival as a nation,’’ Richardson wrote in what he calls his design for the future, released Tuesday.

It also is a gigantic investment, estimated at $100 billion. Russia and China are both modernizing their nuclear forces, although not every expert agrees that this alone justifies to do the same, at huge expense.

Associated Press