Researchers at Oak Ridge National Laboratory (ORNL) are studying neptunium, a rare radioactive element.<\/p>\n
It serves as the primary building block for the plutonium-238 used to power long-range spacecraft.<\/p>\n
This work is vital for deep-space exploration, as Pu-238 powers the Radioisotope Thermoelectric Generators (RTGs) used in missions such as NASA\u2019s Perseverance Rover.<\/p>\n
RTGs transform the heat from decaying matter into electrical power for spacecraft.\u00a0<\/p>\n
Unlocking neptunium\u2019s secrets<\/p>\n
Standard solar panels and lithium-ion batteries are often insufficient for the extreme conditions of deep space.\u00a0<\/p>\n
Hence, plutonium<\/a>-powered batteries are the only viable solution for sustaining scientific instruments on long-range missions.\u00a0<\/p>\n As NASA\u2019s ambition for complex space exploration grows, so does the demand for these nuclear power<\/a> sources, making efficient production a necessity for future discovery.<\/p>\n To maximize the potential, the researchers are working to master the materials science behind RTGs. This involves a rigorous dual focus on both chemical reactions and structural characterization \u2014 areas in which ORNL specializes.\u00a0<\/p>\n \u201cThe demand always exceeds our supply. Hence, we need to have a great understanding of neptunium chemistry to support the production of Pu-238,\u201d said Kathryn Lawson, radiochemist in ORNL\u2019s Fuel Cycle Chemical Technology Group.\u00a0<\/p>\n The team is using a process called thermal decomposition to unlock the chemical secrets of neptunium. The process involves systematically breaking down neptunium using controlled heat between 150\u00b0C and 600\u00b0C (302 to 1,112\u00b0F).\u00a0<\/p>\n Through this, the ORNL researchers have pinpointed the material\u2019s \u201cintermediate phases,\u201d or the hidden stages it passes through during transformation.<\/p>\n Chemical fingerprint of the element<\/p>\n In this work, the team merged physical data from Raman spectroscopy \u2014 which uses lasers to map molecular vibrations \u2014 with advanced computational modeling.<\/p>\n It led to an analysis of the internal mechanics of neptunium. This hybrid approach led to the first-ever \u201cstructural fingerprint\u201d of a vital neptunium oxide, providing a mathematical and visual roadmap for its behavior.<\/p>\n \u201cEssentially what we do is use Raman spectroscopy to shoot lasers at the sample and excite different vibrations in the structure of the material,\u201d said nuclear security scientist Tyler Spano.<\/p>\n \u201cWhat comes out is a series of peaks, a spectrum. That tells us something about the current material structure, but what we did was follow the heating pathway that Kathryn [Lawson] uses for the material,\u201d said<\/a> Spano.<\/p>\n The team performed these measurements under active heating, which provided a step-by-step view of how the material\u2019s bonding environment responded to thermal stress.<\/p>\n Having proven their measurement capabilities, the ORNL team is now moving on to study other poorly understood neptunium compounds.\u00a0<\/p>\n They aim to uncover new chemical pathways that could further streamline the creation of deep-space fuel<\/a>.<\/p>\n This research marks a \u201cresurgence\u201d in neptunium study, driven by a tight-knit group of early-career scientists.\u00a0<\/p>\n