The people of stockpile stewardship are the key to LLNL’s success

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From top left: David Heinrichs, Irene Yee, Teresa Bailey, Leslie Positeri, Kim Ferrari, Cynthia Nitta, Omar Hurricane, Rick Kraus and Brad Wallin.

The last nuclear test, code-named Divider, took place 30 years ago, on Sept. 23, 1992. That year, President Bush declared a temporary moratorium on nuclear testing, which became permanent during the Clinton administration. This ending of the era of nuclear testing was also the beginning of stockpile stewardship.

Leaders from the Department of Energy (DOE), and Lawrence Livermore, Los Alamos and Sandia national laboratories, convened to develop a strategy and map out an R&D effort that would come to be known as the Stockpile Stewardship Program (SSP). Its mission was ensuring the readiness of the nation’s nuclear deterrent force without nuclear tests. 

This third article of a series surveys the people of stockpile stewardship and the variety of the work that they perform to support the mission, as well as how that work has evolved. All LLNL employees support the stewardship mission in one way or another — in scientific and engineering roles, and in many more occupations. A few of their stories are told here.

For every team setting up a hydrodynamic experiment or running a high-energy density simulation, dozens of other employees are supporting them by ordering material supplies, procuring the next high-performance computer, maintaining safe working environments in labs, providing training to perform work more effectively, planning and building new facilities or hiring new employees to help with the expanding workload.

The work of Livermore employees has changed in some ways, but it has remained the same in others. As the needs of the stockpile stewardship mission have evolved, the Laboratory and its people have evolved along with them. What stands out over the last three decades is how the Laboratory’s employees have adapted to that change and fostered cooperation to meet their goals. The challenges of recruiting and growing the workforce to handle the increasing workload is another theme that emerges from discussions with both longtime and newer employees.

Safety support roles evolve

Working safely has always been a focus. In time, increasing sophistication about how to work safely became ingrained in Laboratory practices. David Heinrichs, leader of the Nuclear Criticality Safety Division, witnessed an evolution in his group’s work between the start of stockpile stewardship and the present day. The criticality safety activity ensures that during the handling and use of fissionable materials like plutonium and uranium, workers do not inadvertently put too large an amount of these materials in proximity sufficient to initiate a nuclear chain reaction, which would release harmful radiation.

“I came to Livermore from the Rocky Flats Plant in ’91,” he said. At the time, Heinrichs was the only non-Ph.D. physicist on the staff. “In those days, we didn’t have the same regulatory requirements — our only requirement was to provide briefings to the Nuclear Explosives Safety Study Group. We didn’t have the same level of regulatory oversight that we have today.”

For him, the mid 1990s were focused on weapons disassembly, and his work required writing criticality safety statements and performing tasks like transportation safety risk assessments. He also cooperated with counterparts at Los Alamos National Laboratory and other parts of the Nuclear Security Enterprise to share nuclear criticality safety practices. With the coming of life extension (LEP) and modification (Mod) programs to the Laboratory, Heinrichs’ division has been involved with the criticality safety assessment of the W80-4 LEP, and they will soon be working on the W87-1 Mod. 

More diverse credentials, and a growing workload

Both Heinrichs’ work and his group have evolved. “In the beginning, everyone was a Ph.D. physicist,” he said. “The last one retired recently. Today, we’ve evolved more into the engineering disciplines. We are hiring more and more nuclear engineers, but also people with systems engineering degrees, engineering physics and engineering mechanics backgrounds.” He notes that the workload is increasing for everyone involved in criticality safety: “All criticality groups are getting bigger because of increasing regulatory demand. Overall, our workload is growing.”

Coping with increased workload is a common theme among Livermore staff today, and one of the antidotes to the growing load is improving cooperation and building trust with others. Mechanical engineer Irene Yee designs and builds hydrodynamic tests that run at Site 300 and Los Alamos National Laboratory’s Dual Axis Radiographic Hydrodynamic Test Facility. Yee has worked at the Lab for five years. She said, “I’ve noticed a huge increase in the number of hydro experiments. It used to be that every hydro engineer used to have just one test in progress. Now, most engineers will have two or three."

Yee’s work requires her to design experiments, meet with stakeholders and look at the procedures and results of past experiments to understand how they were done.

“Today, I go to the shops every single day to check on the progress of parts I’ve asked for. I talk to machinists, who are creating parts that require quite high precision. I put a lot of trust in them — I’ve learned so much from them because I’m so early in my career,” she explained.

Greater skillsets are sought

Livermore’s employees often work on more than one team, and on more than one project at a time. Today, they also need a greater array of skills to meet their objectives. “When I was in grad school, it was good enough to develop a numerical method and demonstrate how to support it,” said Teresa Bailey, associate program director for Computational Physics in the Weapon Simulation and Computing Program. “Today, you have to design a numerical method, demonstrate that it works on parallel systems and that it runs on and will scale up on a graphics processing unit platform.”

“More attention is paid today to ensuring that the method and the algorithm will scale up,” she continued. “We must demonstrate scalability and applicability to advanced architectures. Our success at turning high-performance computing into a field has led to greater integration between code and hardware development — they are merging. Also, mathematical and physical models are merging,” she noted. “Within code teams, each code developer is expected to know more. The code teams have become more integrated — they need to have multiple skill sets and the ability to work together on hard problems.”

Finding the people with the right skills to work on these increasingly challenging problems is itself proving to be a challenge.

Training learns to adapt

“I remember the end of the Cold War in 1991,” said Technology Lead for Learning Development Leslie Positeri. “It was a moment where you remembered exactly where you were when the news was announced. We realized that a lot of things would be different at the Lab.” Positeri has seen the changes at the Laboratory through the lens of her work in developing training courses and providing educational opportunity to Lab staff.

“The training community has to be flexible in how we do business,” she said. “When I started at the Lab in 1989 was when we first started seeing technology coming into the classroom. We work on deploying technology and learning development so that people can get the skills they need to meet their goals and support their mission. Today, this activity doesn’t necessarily mean being in a classroom.” As the Laboratory experienced the external changes that happened in the world, she and her colleagues had to adapt.

“A big boom took place around safety training around this time in the mid-1990s,” she explained. “We had to develop hundreds of new courses. NIF, Superblock and other areas of the Lab needed dozens of new courses. When 9/11 happened, we saw a lot of changes around cybersecurity. Global changes impact how we do business, so the training community has to respond quickly. When COVID hit, we couldn’t stop offering Lab courses, so we now had to figure out how to offer them virtually.” Over time, she also saw an increase in the number of staff taking advantage of the Education Assistance Program for degrees and professional development. Today, an increased focus on leadership training and employee development keeps her organization busy.

Responding to world events, security gets upgrades

Kim Ferrari, the Product Development and Release lead for the Laboratory’s Security Protection Program, agrees. “We are always upgrading our systems with new technology. This has been a constant in the 25 years I’ve been here,” she said. Ferrari’s group protects nuclear assets by maintaining the Argus system, which provides physical access controls and intrusion detection around the Laboratory. Her group also supports six other sites, including Pantex and Y-12, Los Alamos and the Savannah River Site. Members of her group include coders from Computing, staff from Engineering, who design the hardware, and an IT team, who keep the system up and running and perform day-to-day maintenance.

During her career, Ferrari went from writing code to managing a group of code writers. “We’ve worked to evolve the Argus system as changes in technology happen.” She has been witness to the increased general interest in security after 9/11, and the recent push for cybersecurity. “Argus is an isolated system, it’s not on the internet, but the cybersecurity push is has become a bigger part of our job,” she said. The Laboratory’s technology directions are influenced by changes in the world and must evolve with them no matter how distant from those changes.

Recruiting a diverse next generation

To stay on track and fulfill mission requirements, the Laboratory needs to continue hiring at a rapid pace. The keys to succeeding will include focusing on hiring from a diverse pipeline, communicating the Lab’s commitment to its equity and inclusion efforts and showcasing the Lab’s many draws, such as its culture of team science and its advanced technology.

“As an intern, it can be quite daunting to come to a place like the Lab,” said Yee. “But, when I was here as an intern, I always received so much help from the people I worked with — I always received the help I needed when I went to ask someone a question. It’s really the people that I worked and interacted with that made me want to come back to Livermore.”

Cynthia Nitta, Livermore’s chief program advisor for Future Deterrent, Weapons Physics and Design, arrived at Livermore prior to the end of the Cold War and the beginning of stockpile stewardship. Nitta says that she came because she heard that Livermore was supportive for women, and she believes that the Lab’s environment is a continued selling point. “Today, I would motivate women to come here by telling them what our mission is, and all the important things you can work on here. Also, it’s an open working environment. You can go into anyone’s office, ask a question and get an answer. I’ve worked at places where you could not do that. In the late 1980s when I arrived, Livermore was a supportive environment for women, although there weren’t that many in the weapons program. It is a more comfortable working environment now because there is more diversity in the workforce.”

Everyone feels like they contribute

Omar Hurricane, chief scientist of NIF’s Inertial Confinement Fusion Program, suggests that inclusion is an important part of the formula to attract next-generation employees. “We want to have an environment where everyone feels like they are contributing something,” he said. Experienced staff should be sharing their knowledge with younger employees: “It’s important for the more senior people to always be engaged with the junior people,” Hurricane explained. “Gaining experience in the scientific method and benefitting from the intuition that the more senior people usually have is how the younger generation learns, while trying to do new things themselves. We need a better way to transfer this experiential learning to the junior people. Science is all about building. We build understanding and capability and transfer it to the next generation. There needs to be a good way to transfer the experience of the senior people to the next generation.” Mentoring relationships between the generations, typical of a university environment, can help address this need, he suggested.

According to Rick Kraus, a research scientist in the Physics Division, “the breadth of fields and specialties has increased. We still need people who have the capability to diagnose an explosive test or lead the engineering on a high-precision device. But with stockpile stewardship, we are also more concerned about topics such as understanding the metallurgical effects of aging or predicting the impact of changing manufacturing methods on how a material behaves. As we get further and further from the last nuclear test, all fields in stockpile stewardship become more important and are of higher consequence.”

The Laboratory’s leading edge scientific tools and technology are a big draw. “I think that the scientific tools are so important. We could not do the modernization programs now without them,” said Brad Wallin. “These are the tools that allow us to prepare for the future — our ability to continue to innovate the science and technology is critical. This is what attracts good talent to the Lab. We want smart people coming here to the Lab to use these tools.”

At the end of the day, it is people…

“At the end of the day, it is people who certify the stockpile,” he concludes. “During the nuclear testing era, people combined these tests with other experiments, simulations and their knowledge and experience, and it is the judgment of people that we depended on. This hasn’t changed; we use the archive of nuclear test data along with the best experimental and simulation tools we have ever had to train our people and make necessary modifications to the stockpile. The people and the tools give us the confidence to certify the stockpile.”

-Allan Chen