Technology Development and Contribution to CTBT - Japan Atomic Energy Agency / Integrated Support Center for Nuclear Nonproliferation and Nuclear Security

Technology Development and Contribution to CTBT

Development of nuclear nonproliferation and nuclear security technologies

Nuclear Forensics

Nuclear forensics in the context of nuclear security is a technical means to support criminal investigations by analyzing the origins, history, transportation routes and intended use of materials out of regulatory control and related evidences seized by law enforcement, based on the measurement of their physical and chemical characteristics such as material compositions. We are working on the development of analytical capabilities necessary for nuclear forensics analysis, nuclear forensics library technology including nuclear and radioactive material databases, as well as radiation measurement technology to support first response at the crime scene by law enforcement.

Nuclear Forensics
Process

Sample Measurement Technique
- Isotope Ratios
- Trace Element Compositions
- Uranium Age Dating
- Morphology Analysis
Nuclear Forensics Library
- Database (Nuclear/Radioactive Material)
- Data Analysis Approach, Tools
- Machine Learning Model Applications
Radiation Measurement Technology for First Responders
- Handheld Radioisotope Identification Device
- Direction-sensitive Gamma Detector

Surface Pattern Analysis of Nuclear Materials
by Deep Learning Model

Active Neutron

Nondestructive assay (NDA) can be classified into passive and active methods. The passive method measures neutrons and gamma rays spontaneously emitted from nuclear materials. In passive methods, when measuring samples such as spent fuel that emits strong radiation from fission products (FPs), the gamma rays and neutrons from the nuclear materials to be measured may be hidden by those of the FPs, making nuclear material measurement difficult. The active methods irradiate the samples with neutrons from outside the containers to induce nuclear reactions and measure their radiation generated by the reactions.

Neutron Resonance Analysis

In Neutron Resonance Analysis (NRA) for measuring nuclear materials (NMs), a sample is irradiated with pulsed neutrons, and the neutron energy that causes resonance reactions with the nuclei in the sample is measured by the time-of-flight (TOF) method. We have developed a Neutron Resonance Transmission Analysis (NRTA) system using a Laser-Driven Neutron Source (LDNS) with the aim of miniaturizing the Non-Destructive Analysis (NDA) system for measuring NMs. We conducted a neutron transmission experiment using an LDNS developed by Osaka University to demonstrate the applicability of LDNS to NRTA. The experimental result showed that the NRTA system equipped with the LDNS successfully identified the nuclides in the sample. Through this research, we demonstrated that a miniaturized NDA system can be expected in the near future. Since 2022, we have been developing Neutron Resonance Fission Neutron Analysis (NRFNA) as a method for accurately measuring a small amount of fissile material.

References

Experimental setup of neutron transmission
measurements using the Osaka LDNS

Delayed Gamma-ray Spectroscopy

Delayed Gamma-ray Spectroscopy (DGS) is a nondestructive assay technique that can be used for nuclear safeguards verification requirements by quickly evaluating the fissile nuclide content in pure or mixed nuclear materials, especially high-radioactivity nuclear material like used nuclear fuel. A DGS interrogation uses neutrons to induce fission in the sample and the gamma rays from the decaying fission products are observed over multiple cycles. We are researching the analytical requirements and developing instrumentation required for reprocessing plant near-term application and full assembly long-term goals.

Spectral Analysis Development
- Timing sensitivity
- Sample effects on spectrum
- Inverse Monte Carlo analysis
- Mass correlations
- Neutron signature correlations
Instrumentation Development
- Fission Signature Assay Instrument for small samples final application
- Delayed Gamma-ray Test Spectrometer for preliminary requirements/effects
- Test Moderator for model validation
- Neutron detector studies for source monitoring and fission signatures

Model of the Fission Signature Assay Instrument applying the DGS technique with neutron signature capabilities

Wide Area Monitoring

ISCN has been developing technology for detecting nuclear and radioactive materials in a wide area since 2020. In this project, we develop a device and system that can efficiently detect nuclear and radioactive materials in wide areas in and around event sites, especially for large-scale public events, such as the Olympic Games and World Expositions.

In order to apply to various situation, radiation mapping system for indoor and outdoor and remote measurement techniques using crawler robot will be implemented.

Radiation mapping systems: 2D/3D SLAM; Remote measurement through LPWA
Techniques for radiation source localization: Gamma-ray imaging; Direction sensitive fast neutron detectors

Concept of wide area monitoring around the stadium

Crawler robot equipped with a radiation detector

Concept of wide area monitoring around the stadium

Other activities

Technology development conducted in the past

CTBT

Scheme of CTBT International Verification Regime

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) prohibits any nuclear weapon test explosion or any other nuclear explosion in any spaces including cosmic space, atmosphere, underwater, and underground, and prescribes establishment of verification regime to verify that each member state adheres the treaty.

Although the CTBT has been ratified by 177 countries, it is currently not yet in force due to non-ratification by the countries required to enter into force. However, in preparation for the future entry into force of the Treaty, 90.2% (304/337) of the four types of International Monitoring System (IMS) facilities (Seismic, Radionuclide, Hydroacoustic and Infrasound) for the detection of nuclear tests, as defined in the Protocol to the Treaty, have installed, certified and operated all over the world. * as of February 2023

Current status of CTBT (as of February 2023): (1) 185 signatories and 177 ratified countries; (2) Of the 44 countries requiring entry into force, 41 signatories and 36 ratifying countries
Of the 44 countries required to enter into force,
Signed / unratified countries (5 countries): USA, China, Egypt, Iran, Israel
Unsigned / unratified countries (3 countries): North Korea, India, Pakistan

ISCN's Contribution to the International CTBT Verification Regime

JAEA has completed the construction of radionuclide station of Okinawa and Takasaki Station, and the Tokai Radionuclide laboratory, which have been certified by the CTBT Organization (CTBTO) as facilities satisfying the technical requirements for nuclear test monitoring and have been in operation. In addition, the national data center (NDC-2) receives radionuclide station data from the International Data Center (IDC) in Vienna, Austria, and analyzes the data on a daily basis. The Okinawa station is located in the Okinawa Tracking and Communication Station of the Japan Aerospace Exploration Agency, and the Takasaki station is located in the Takasaki Advanced Radiation Research Institute of the Japan Quantum Science and Technology Agency. The Tokai Radionuclide laboratory and NDC-2 are located in the Nuclear Science Research Institute of JAEA.

As shown in the figure below, JAEA plays three roles in the CTBT international verification regime, operation of radionuclide stations, radionuclide laboratory and NDC-2. JAEA actively cooperates with the government.