World’s First Table-Top System for Non-Destructive Isotope Analysis Using a Fingertip-Sized Neutron Source – Toward On-Site Identification of Nuclear Material Isotopes  – 

2026.02.03

Fig. 1 Comparison between a conventional NRTA system (left) and
the developed table-top NRTA system (right).

Nuclear Science and Engineering Center (NSEC) has developed a prototype system as an important step toward realizing a table-top instrument for the non-destructive assay (NDA) of nuclear material (NM) isotopes. Accurate isotope measurements by NDA are essential for proper nuclear fuel management and the prevention of illicit use of NMs.

NMs such as uranium and plutonium contain multiple isotopes with different neutron numbers. The isotopic composition determines key properties, including suitability as nuclear fuel and potential for weaponization. Therefore, accurately evaluating not only the total amount of NM but also the types and abundances of its isotopes is essential for nonproliferation and nuclear security.

Conventional NDA techniques generally struggle to distinguish isotopes. Although neutron resonance transmission analysis (NRTA) enables isotope identification, it has traditionally required highly specialized infrastructure such as large-scale accelerators or dedicated neutron sources. Consequently, NRTA measurements have been difficult to conduct in space-limited facilities, non-radiation-controlled areas, or outdoor environments. To overcome this limitation, NSEC has established an NRTA technique using a fingertip-sized californium-252 neutron source and developed the world’s first table-top NRTA system that enables isotope identification without the need for large-scale specialized facilities (Figure 1). Test measurements using simulated samples with resonance energies close to those of NMs demonstrated the system’s ability to differentiate isotopes. This result opens the way to nondestructive, on-site isotope measurements in environments where conventional NRTA has been impractical.

This achievement represents an important milestone toward the practical realization of a compact NRTA system capable of isotope measurements of NMs. Future efforts will include validation using actual NMs, improvements in measurement precision, and expansion of the range of measurable isotopes. In addition to contributing to nonproliferation and nuclear security, this technique holds promise for a wide range of applications requiring nondestructive isotope analysis, including age dating and provenance studies in archaeology, as well as the analysis of samples returned from space exploration.

The results of this study have been published in Communications Engineering, an open-access Nature Portfolio journal, on January 23, 2026.
Article information: https://doi.org/10.1038/s44172-025-00564-6

JAEA HP Press release (Japanese only)