Controlling nuclear weapons and the means to make them is essential to keeping the most deadly weapons from reaching terrorists. CISAC researchers work to find ways of improving the safety and security of existing weapons and to secure the materials and technology for making new nuclear weapons. Past and curent research projects have dealt with protecting dangerous nuclear and other radioactive materials from theft, terrorism and unathorized use and examining security systems at nuclear facilities to reduce vulnerabilities. CISAC scholars have contributed to U.S.-Russian cooperative threat reduction programs and continue to advise U.S. and international policymakers on nuclear security issues.