First testing completed on prototype transfer system for Savannah River Site pit production

• By Matthew Christian mchristian@aikenstandard.com
• September 14, 2022

Kristen Phillippi, an operations support specialist with Savannah River Nuclear Solutions, loads a 10-pound bag into the test transport container that sits on a cart driven by magnetic technology within the prototype of the material transfer system. Submitted Photo

Plutonium pit production facilities at the Savannah River Site have taken a step forward. 

Savannah River Nuclear Solutions, the manager and operator of the 310-square-mile site located south of Aiken, announced Sept. 12 that a material transfer system that will be central to pit production operations has successfully completed its first round of testing. 

Pits are an essential component of nuclear weapons.

In order to understand what pits are, it’s important to remember that all matter is composed of millions of tiny atoms, that atoms consist of protons, neutrons and electrons and that protons and neutrons form the nucleus at the center of an atom.

Normally, the nucleus of an atom is stable and doesn’t change, but the nuclei of certain elements – hydrogen, uranium and plutonium – can begin to change when an extra neutron is added. When a neutron is added to uranium or plutonium, the nucleus splits into smaller versions of itself, releasing energy and neutrons. This is known as nuclear fission.

Those neutrons can cause a chain reaction when they’re absorbed by nearby atoms of uranium or plutonium. In nuclear weapons, this chain reaction is uncontrolled and begins when neutrons are injected into a plutonium shell, called a pit, by an inward-focused explosion. Over time, the plutonium in these shells can begin to change on its own, which necessitates their replacement every so often.

The National Nuclear Security Administration has announced plans to construct replacement pits at the Savannah River Site and Los Alamos National Laboratory in New Mexico. At the Savannah River Site, 50 pits per year would be built at the failed MOX facility. 

“The material transfer system will be the veins and arteries of the SRPPF [pit production facility], moving material from beginning to end of the production process,” Patrick Schneider, Savannah River Nuclear Solutions plutonium modernization manager of operations, said in a news release. “Designing, assembling and testing a prototype of the transfer system now will allow the development of a final system that works seamlessly with the production processes.”

The Savannah River National Laboratory worked with the National Nuclear Security Administration to develop the system. 

“Bringing together this cross section of functional organizations at this early stage in the project will support our future success,” Schneider said.

The national lab began developing the system by researching available technologies for moving materials and items through the system. They evaluated the different technologies to determine which would be the most effective, have the fewest moving parts and be the easiest to maintain. After looking at pulley-driven, chain-driven and others, a magnetic drive was selected as the best option because it does not present maintenance challenges like chains that need lubrication or belts that stretch over time.

Next, the lab assembled the first version of the system and operated it in the lab to make sure it would run. It was then transferred to an existing facility that will eventually become the training and operations center for the pit production facility where a three-person operations team began putting it through its paces. The prototype had to demonstrate movement laterally and around corners. The final test was a multi-phase endurance test to ensure that it could transport more than the required weight over a four-week period.

Each phase required the system to run 24/7 for a week. The test began with a nearly 10-pound empty cart operating for the first week. A 10-pound bag was added to the cart for the second week, then a third 10-pound bag was added for week three, and finally, another 10-pound bag was added to complete the month-long test.

“When we got to 40 pounds, it was still operating and functioning, so we know it can do what’s needed,” Schneider said. “The magnetic-driven technology proved to be efficient and low maintenance.”

Information gained from testing has been shared with the glovebox design team. They will update the system’s design, based on improvements indicated by the testing. Then the updated system will be assembled and testing will begin again.

Pit production is slated to begin in the mid-2030s at the Savannah River Site.