If a plumber needs a part for a water heater or a groundskeeper needs a part for a lawnmower, they can just go to the nearest home improvement store. It’s much more complicated if a worker at the Y-12 National Security Complex needs a part for a machine.
Located in nearby Oak Ridge, Y-12 maintains the safety, security, and effectiveness of the U.S. nuclear weapons stockpile, and uses extremely specialized, highly regulated equipment in many aspects of its work. Restocking spare parts to maintain this equipment must be carefully calculated to remain within timeliness, cost, and storage requirements.
Hugh Medal, an assistant professor in the Department of Industrial and Systems Engineering (ISE), is leading an inventory optimization project at UT to create a digital model that helps Y-12 determine a more accurate, data-based forecast for stocking critical spare parts and general inventory.
“It’s a decision support tool that helps them determine the stocking level to ensure it’s not too small and not too large,” Medal said. “If it’s too small, then they might run out of parts and have to shut down production. That is a big problem. And if it’s too large, then they’re spending more money than they should, and they might run out of space.”
The model considers the fact that some parts may become obsolete and are no longer made by a supplier. It also factors in the uncertainty of how much Y-12 will need the spare part. This consideration and proactive planning for obsolescence can mitigate long-term risk over the life of a project.
“Obviously, the model is not going to make the decision for them. But it represents a quantitative approach, and it also represents a transparent approach,” Medal said. “It’s not just one person who has an opinion of ‘we should stock 10 parts,’ and another person who thinks ‘we really only need three since this part is not used very much.’ The model can provide a platform for different teams working together.”
Making the right calculations
The Y-12 project began to take form three years ago. Carla Arbogast, the director of ISE’s Center for Advanced Research & Education, was instrumental in the launch of the project. Late ISE Professor Rupy Sawhney was the initial principal investigator, and Medal assumed the role following Sawhney’s death.
Various graduate and undergraduate students have worked on the project over the years to help push it forward. PhD student Chad Uhles joined the team in January and has been working on the math and coding behind the model.
“Y-12 had a baseline approach, but we’re trying to expand upon that to make the numbers that the model outputs more realistic,” Uhles said. “I’m trying to figure out different probability distributions. What’s the underlying math going on behind that? What assumptions were we making with the previous model that we would like to relax a little bit to try to make our model and our results a little bit more realistic?”
Along with his role in the computations, Uhles has been serving as a mentor for three undergraduate students in the group this semester.
“They’ve been very hands-on in helping out with a lot of the writing that we’re having to do,” Uhles said. “They’ve also been able to see a little bit of what’s going on behind the curtains as far as some of the math that’s going on.”
Practical outcomes
Uhles has enjoyed working on a project that is pragmatic and will produce an outcome that can benefit a facility right away.
“There are times that you can work on a project or work on an idea, and yes, it is interesting, and it does provide some value, but it’s a very theoretical problem,” Uhles said. “What we are doing with Y-12 is a very practical problem that we can tailor and fine tune to the purposes of Y-12. That is the most rewarding thing, and one of the things that keeps me motivated on the project.”
Ashley Craig-Watkins, of Y-12’s supply chain, hopes that students also take the chance to learn more about Y-12 and its work.
“We hope they gain knowledge about the Y-12 mission and the significance of its role for the nation,” Craig-Watkins said. “It has been a great pleasure working with the UT students and their leader, Dr. Hugh Medal. The opportunity to collaborate with them on this topic has been a great learning experience for all of us.”
Medal views the project as win-win all around, with students helping create a tool that makes efficient use of government tax dollars while also helping Y-12 fulfill its mission.
“Hopefully the research that we’re doing is valuable to Y-12, but it’s also really valuable for the students to get a chance to work on a real project and something that matters,” Medal said. “It gives the students a chance to work on a government project, and to kind of contrast that with their internships, where they’ve been working probably in the private sector. It’s been a great learning experience for everyone involved, including me.”
Contact
Rhiannon Potkey (865-974-0683, [email protected])