(Senator Nunn and Senator Richard Lugar) initiated a modest, bipartisan, $400-million-a-year program of investment in securing Russian nuclear weapons and materials.

As of this report from 2011, nearly 92% of 'loose nuke' material and sites had been secured:
http://nnsa.energy.gov/mediaroom/factsheets/protectioncontrolaccounting

more here:
http://www.cfr.org/arms-control-disarmament-and-nonproliferation/global-nuclear-nonproliferation-regime/p18984

"The Obama administration brought additional attention to this issue, pledging to secure all vulnerable nuclear weapons materials by 2014 and convening a high-level global nuclear security summits in 2010 and 2012. The 2010 summit yielded tangible results, with Ukraine announcing that it would get rid of all its Soviet-era highly enriched uranium, and five other countries stating intentions to convert their research reactors to run on low-enriched uranium, which is less dangerous. The next global nuclear security summit is planned for 2014 and will take place in the Netherlands."

Pres. Reagan projected a outward bluster of tough stands, and greatly re-ignighted the Cold war and nuke insecurity. He had nothing to do with ending the Cold War for which many falsely give him credit.