The benchmark experiment on slab beryllium with D–T neutrons for validation of evaluated nuclear data

“…The accumulation of radionuclides is a problem related to the maintenance, replacement cycle, performance degradation of components, and decommissioning of devices. Simulations and analyses of activation by fusion neutrons have been reported, which have focused on the prediction of radioactive waste and its regulation [1,2]; estimation and experiments of hydrogen isotopes inside the whole system of fusion devices or their plasma-facing walls, divertors, and components [3,4]; and comparison between fission and fusion power plants [5]. In particular, predictions at the decommissioning step are essential because specific radionuclides with long half-lives (several years) accumulate inside the components.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Gamma-Ray Dose Distribution in the Toroidal Direction of LHD Vacuum Vessel from Radionuclides Generated in Deuterium Plasma Experiments

Ogino,

Kobayashi,

Mukai

et al. 2024

International Journal of Energy Research

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The evaluation of activities from radionuclides inside a vacuum vessel is required for the safe maintenance and estimation of the activation level of fusion devices. The Large Helical Device (LHD), Toki, Japan, has been performing deuterium plasma experiments since 2017, and radionuclides have accumulated in components such as vacuum vessels. In this work, the gamma-ray spectrum and activity of each detected radionuclide in an LHD vacuum vessel were evaluated using portable high-purity germanium (P-HPGe) and numerical calculations of photon transport for comparison with the removed armor tiles to evaluate the occupational exposure in the maintenance of LHD experiments. Measurements using the P-HPGe detector were performed at 20 positions along the toroidal direction of the LHD, at each O port, and between each pair of adjacent O ports. Using the estimated efficiency of the photoelectronic effects inside the P-HPGe detector calculated by Monte Carlo N-particle code version 6.1, the activities of the radionuclides in the armor tiles attached to the vacuum vessel were evaluated. The estimated activity concentrations were compared with the measured activities of the armor tiles removed from the vacuum vessel. Gamma rays from 58Co, 54Mn, and 60Co were detected, and the measured activities of 58Co and 54Mn generated by fast neutrons in the armor tile were almost consistent with those obtained from the removed armor tiles. The radioactivity of 60Co in the armor tile was underestimated compared with the activity obtained from the removed armor tiles. The measurement of activation by fast neutrons is feasible, whereas activation by thermal neutrons requires more accurate calculations and surveys to be measured using this method.

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“…In order to validate currently available nuclear data files for iron, the leakage neutron spectra from iron slabs were measured and calculated at CIAE by using the integral benchmark facility, which has been successfully used in a series of benchmark experiments [7][8][9][10]. The leakage neutron spectra from iron slabs were measured between 0.8 MeV and 15 MeV at emission angles of 60• and 120• using TOF method with a BC501A scintillation detector.…”

Section: Introductionmentioning

confidence: 99%

Benchmark experiment with iron slab by Time-of-flight technique at CIAE

et al. 2020

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In order to validate the evaluated nuclear data, leakage spectra in the range of 0.8 to 15 MeV from samples were measured by time-of-flight (TOF) technique using a D-T neutron source. An experimental system for benchmark validation of nuclear data with slab samples has been set up at China Institute of Atomic Energy (CIAE). In this study, test samples are iron slabs, of which the thickness are 5cm, 10cm and 15cm, and the measured angles were chosen to be about 60° and 120°. By comparing measured leakage spectrum with calculated ones by MCNP-4C code, using the data from the CENDL-3.1, ENDF/B-VIII.0, JENDL-4.0 and JEFF-3.3 nuclear data files, and the comparison was made by the spectrum shape and by the C/E values in different energy regions.

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The benchmark experiment on slab beryllium with D–T neutrons for validation of evaluated nuclear data

Cited by 17 publications

References 12 publications

Recent progress in nuclear data measurement for ADS

Recent progress in nuclear data measurement for ADS

Evaluation of Gamma-Ray Dose Distribution in the Toroidal Direction of LHD Vacuum Vessel from Radionuclides Generated in Deuterium Plasma Experiments

Benchmark experiment with iron slab by Time-of-flight technique at CIAE

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