The <a href="https://en.wikipedia.org/wiki/Soviet_Union" id="mw4g" rel="mw:WikiLink" title="Soviet Union">USSR</a>'s nuclear program receives plans for the United States <a href="https://en.wikipedia.org/wiki/Nuclear_weapon" id="mw4w" rel="mw:WikiLink" title="Nuclear weapon">plutonium bomb</a> from <a href="https://en.wikipedia.org/wiki/Klaus_Fuchs" id="mw5A" rel="mw:WikiLink" title="Klaus Fuchs">Klaus Fuchs</a> at the <a href="https://en.wikipedia.org/wiki/Los_Alamos_National_Laboratory" id="mw5Q" rel="mw:WikiLink" title="Los Alamos National Laboratory">Los Alamos National Laboratory</a>.