WEAPONS refurbishment efforts called life-extension programs (LEPs) enable the National Nuclear Security Administration (NNSA) to maintain the nation’s nuclear deterrent without resuming the production of new weapons or underground nuclear tests, both of which ceased roughly a quarter century ago. (See S&TR, March 2012, Extending the Life of an Aging Weapon; July/August 2010, Enhancing Confidence in the Nation’s Nuclear Stockpile.) Sustaining the legacy manufacturing processes used for LEP component production is growing increasingly challenging for the NNSA laboratories and production facilities, which are tasked with keeping the aging weapons safe and operational. Many of the procedures are five decades old and geared toward mass production of weapons components. They entail lengthy multistep methods, expensive facilities, large lot sizes, and undesirable levels of hazardous waste generation. Some processes are no longer operationally feasible because of environmental issues, while others call for materials difficult to obtain.
Advanced manufacturing technologies such as additive manufacturing (AM), together with high-performance computing (HPC), could be used to develop next-generation manufacturing processes and materials for the NNSA complex. AM methods, in which layers of material are built up as prescribed in a digital file, can be used to quickly, easily, and precisely create objects with complex shapes. The superior material design and manufacturing process control available through AM can facilitate the creation of objects with more desirable material properties and performance than conventional subtractive manufacturing technologies. AM is already being exploited by a wide range of industries to drastically reduce product development and production time lines, particularly for low-volume specialty parts and tooling.
Recognizing that AM could greatly benefit national security missions, NNSA has launched a multiyear, multipronged initiative to explore, mature, and adapt the most promising commercial AM technologies and to develop new techniques. NNSA’s success will rely on the manufacturing expertise of its production plants and the unique science-based stockpile stewardship capabilities of its laboratories. “For NNSA to realize additive manufacturing’s important benefits in a reasonable time frame, it needs multidisciplinary labs such as Lawrence Livermore working closely with its production plants,” says Melissa Marggraff, deputy principal associate director for Livermore’s Weapons and Complex Integration Principal Directorate and coordinator for NNSA’s many AM activities. “We have materials science, engineering, high-performance computing, and certification expertise that can help make this effort a success.” Lawrence Livermore has five AM labs and more than 80 material scientists, chemists, physicists, engineers, and computational scientists developing advanced materials and manufacturing processes