Quantitative visualization of a radioactive plume with harmonizing gamma-ray imaging spectrometry and real-time atmospheric dispersion simulation based on 3D wind observation

Nagai, Haruyasu; Furuta, Yoshihiro*; Nakayama, Hiromasa; Satoh, Daiki

Journal of Nuclear Science and Technology, 60(11), p.1345 - 1360, 2023/11

https://doi.org/10.1080/00223131.2023.2197445

A novel monitoring method for the quantitative visualization of 3D distribution of a radioactive plume and source term estimation of released radionuclides is proposed and its feasibility is demonstrated by preliminary test. The proposed method is the combination of gamma-ray imaging spectroscopy with the Electron Tracking Compton Camera (ETCC) and real-time high-resolution atmospheric dispersion simulation based on 3D wind observation with Doppler lidar. The 3D distribution of a specific radionuclide in a target radioactive plume is inversely reconstructed from line gamma-ray images from each radionuclide by several ETCCs located around the target by harmonizing with the air concentration distribution pattern of the plume predicted by real-time atmospheric dispersion simulation. A prototype of the analysis method was developed, showing a sufficient performance in several test cases using hypothetical data generated by numerical simulations of atmospheric dispersion and radiation transport.

Distance for fragmentation of a simulated molten-core material discharged into a sodium pool

Matsuba, Kenichi; Isozaki, Mikio; Kamiyama, Kenji; Suzuki, Toru; Tobita, Yoshiharu

Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 7 Pages, 2014/12

In order to develop an evaluation method of the distance for fragmentation of molten core material discharged into the sodium plenum, a sodium experiment with visual observation was conducted using an X-ray imaging system. In the current experiments, 0.9 kg of molten aluminum (initial temperature: around 1473 K) was discharged into a sodium pool (initial temperature: 673 K) through a nozzle (inner diameter: 20 mm). Based on the experimental results, the distance for fragmentation of the liquid column was estimated to be 100 mm in the experiments. Through the sodium experiment, useful knowledge was obtained for the future development of an evaluation method of the distance for fragmentation of molten core material. As a next step, sodium experiments using higher-density molten materials will be conducted to enrich the experimental knowledge. Besides, a new semi-empirical correlation will be developed to evaluate more appropriately the distance for fragmentation under CDA conditions.

("3D"+"2D+Time") visualization of vapor/water in the reactor observed by neutron beam

Kureta, Masatoshi

VizJournal, (11), 5 Pages, 2004/06

This paper explains the neutron radiography thermal-hydraulic measurement technique, especialy visualization technique, which was developed at Japan Atomic Energry Research Institute. Observation of large and fine-mesh data obtained by the new measurement technology is important from a research point of view. We developed the advanced visualization software which puts into practice effective observation by using new visualization methods, and we made the vizualization of phenomena possible by using VR and/or animation displays etc. by this system. Especially in this paper, the visualization techniques which were used in a prize-winning work of the "Visual Sience Festa 2003" by NIKKEI SCIENCE as easy to read for a general reader as possible by using many figures and movies.

ALPHA visual data collection STX005-025; Melt drop steam explosion experiments

Moriyama, Kiyofumi; ; Maruyama, Yu; Kudo, Tamotsu; Sugimoto, Jun

JAERI-Data/Code 99-017, 34 Pages, 1999/03

JAERI-Data-Code-99-017.pdf:7.96MB

no abstracts in English