Category Archives: Nuclear Back-end and Transmutation Technology for Waste Disposal

Measurement Activities by the Activation Method

Neutron capture cross sections were determined on the basis of Westcott’s conven­tion [1] by an activation method. The results for LLFPs [2—23] are listed in Table 5.1, and for MAs [24—31] in Table 5.2, together with previously reported data. Here, the symbols oeff, o0, and /0 denote the effective cross section, the thermal neutron capture cross section, and the resonance […]

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Theory of Power Spectral Density in ADS

Another subcriticality measurement technique is the power spectral density method. This chapter focuses on the cross-power spectral density (CPSD), which is the Fourier transformation of a cross-correlation function between two neutron detector signals. In an infinite and homogeneous subcritical system where the energy and spatial dependence of the neutron is neglected, the CPSD is simply expressed as a function of […]

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Nuclear Back-end and Transmutation Technology for Waste Disposal

On March 11, 2011, a massive earthquake and the resultant tsunami struck the Tohoku area of Japan, causing serious damage to the Fukushima Daiichi Nuclear Power Plant (NPP) and the release of a significant quantity of radionuclides into the surrounding environment. This accident underlined the necessity of establishing more comprehensive scientific research for promoting safety in nuclear technology. In this […]

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Outline of TEF-P

Several neutronic experiments for ADS have been performed in both Europe [6, 7] and Japan. In Japan, subcritical experiments with fast neutron spectrum core were performed at the Fast Critical Assembly (FCA) in JAEA/Tokai, and subcritical experiments with thermal subcritical core driven by 100 MeV protons are performed at Kyoto University Research Reactor Institute. Many experimental studies also have been […]

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Effect of Irradiations on Surface Wettability

Figure 10.4a-c shows the wettability change from ultraviolet, y-ray, and proton-beam irradiation, respectively. The horizontal axis denotes an integrated irradiation dose or irradiation time and the vertical axis denotes the measured contact angle. As shown in these figures, the contact angle decreases with the irradiation dose. In these experi­ments, the ambient effect is also studied during the irradiations, which are […]

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Measurement Activities at J-PARC/MLF/ANNRI

A new experimental apparatus called the accurate neutron nucleus reaction mea­surement instrument (ANNRI) has been constructed on the beam line no. 4 (BL04) of the MLF in the J-PARC. The ANNRI has two detector systems. One of them is a large Ge detector array, which consists of two cluster-Ge detectors, eight coaxial­shaped Ge detectors, and BGO Compton suppression detectors; the […]

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Design of Spallation Target for TEF-T

To evaluate the feasibility of a designed beam window of TEF target, numerical analysis with a three-dimensional (3D) model was performed. The analysis was done by considering the current density and shape of the incident proton beam to the target and the thermal fluid behavior of Pb-Bi around the beam window as a function of flow rate and inlet temperature. […]

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Experiments for NRD Developments

To evaluate systematic uncertainties in NRD, we have started experimental study at GELINA [5] under the collaboration between JAEA and EC-JRC-IRMM. The items to be studied are as follows: (1) particle size, (2) sample thickness, (3) presence of contaminated materials, (4) sample temperature, and (5) the response of the TOF spectrometer [3, 17]. Some experiments has been performed at GELINA […]

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