He did not do that nor is that why he won the prize.
http://www.huffingtonpost.com/2009/10/09/obama-wins-nobel-peace-pr_n_314907.html
and praised his pledges to reduce the world stock of nuclear arms
http://www.reuters.com/article/2012/08/31/us-usa-nuclear-arms-idUSBRE87U06B20120831
"I state clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons," he said to applause.
...
The document that would define how deeply the United States is prepared to cut back its nuclear arsenal - perhaps to 1,000 warheads or less - and how radically to alter U.S. nuclear doctrine is still awaiting Obama's final approval.
http://www.ens-newswire.com/ens/oct2009/2009-10-09-01.asp
http://abcnews.go.com/GMA/Politics/...ms-reduction-treaty-replace/story?id=10318006
President Obama and Russian President Dmitri Medvedev signed a new nuclear disarmament treaty in Prague today, replacing the Strategic Arms Reduction Treaty (START) that expired Dec. 5.
http://www.nytimes.com/2009/07/05/world/05nuclear.html?pagewanted=all&_r=0
In college, Barack Obama wrote about nuclear arms. As a senator, he viewed a deactivated Russian nuclear missile.