Dual-neutron integral experiments close data gaps in lead nuclear benchmarking for safer reactors and fusion systems
Bridging global data gaps to enhance reactor safety, fusion technology, and precision radiation protection
image: The figure illustrates the experimental setup used to measure neutron leakage spectra from natural lead (natPb) slab samples, employing both D-T and D-D neutron sources at the integral experiment platform of the China Institute of Atomic Energy (CIAE). The pulsed neutron beam irradiates the natPb samples placed at different thicknesses (5 cm, 10 cm, and 15 cm), while neutron detectors are positioned at 60° and 120° to record the angular distributions of emitted neutrons using the time-of-flight (TOF) technique. The system incorporates a collimated beamline and heavy shielding to suppress background scattering and improve signal clarity. This layout enables high-precision measurement of neutron transport properties, supporting the benchmarking of evaluated nuclear data libraries critical for nuclear reactor design, fusion technology, and radiation shielding.
Credit: Yang-Bo Nie
Advancing Nuclear Data Validation for Lead Materials
The research team from CIAE and Lanzhou University successfully completed a series of integral experiments targeting natural lead (natPb), utilizing an advanced pulsed D-T and D-D neutron experimental platform. Through a unique geometric design, they achieved precise measurements of neutron leakage spectra at 120°, effectively filling the long-standing international gap in large-angle scattering data—critical for fusion and shielding applications.
Why Accurate Lead Nuclear Data Matters
Lead is a core material in nuclear engineering, extensively used in reactor shielding, radiation protection, and cooling technologies for advanced nuclear systems. However, discrepancies in evaluated nuclear data libraries at large scattering angles have posed challenges for accurate design and operational safety.
This study systematically compared four major nuclear data libraries—CENDL-3.2, JEFF-3.3, JENDL-5, and ENDF/B-VIII.0—revealing significant overestimations and underestimations in elastic and inelastic scattering regions, thus clarifying future directions for nuclear data refinement.
Advanced Experimental Design Ensures Robust Validation
The experiments employed natPb slabs of various thicknesses (5 cm, 10 cm, and 15 cm) and implemented multi-parameter detection of source neutrons. High-precision leakage neutron spectra were obtained using the time-of-flight (ToF) technique, with system calibration verified through polyethylene standard samples. The combined use of D-T and D-D neutron sources provided an unprecedented energy range coverage, ensuring the comprehensiveness and depth of nuclear data validation.
Dr. Yang-Bo Nie, corresponding author, emphasized:
"Our study provides new authoritative benchmark data for the evaluation and improvement of current nuclear data, and offers critical support for the future development of safe and efficient nuclear technologies."
Empowering a Wide Range of Nuclear Technology Applications
The results of this research are expected to have broad applications, including:
Fusion Reactor Design: Optimizing blanket and shielding structures.
Reactor Safety: Enhancing the reliability of neutron transport simulations.
Radiation Protection: Improving shielding for medical, industrial, and aerospace applications.
Accelerator-Driven Systems (ADS): Providing more accurate designs for targets and shielding materials.
The complete study is accessible via DOI：10.1007/s41365-024-01623-x
Nuclear Science and Techniques (NST) is a peer-reviewed international journal sponsored by the Shanghai Institute of Applied Physics, Chinese Academy of Sciences. The journal publishes high-quality research across a broad range of nuclear science disciplines, including nuclear physics, nuclear energy, accelerator physics, and nuclear electronics. Its Editor-in-Chief is the renowned physicist, Professor Yu-Gang Ma.