Yasuaki Watanabe

Study of reactivity control method by the application of gadolinium hydride to accelerator-driven system

A reactivity control method for accelerator-driven system (ADS) is studied for its ability to reduce both the maximum beam current and the load on the beam window. A burnable position (BP) assembly (with gadolinium and zirconium hydride pins) is applied to the ADS core for reactivity control, and various BP assembly optimizations (such as pin arrangement, BP assembly loading position, and BP composition) are performed to minimize the burnup reactivity swing. These optimizations lead to a decreased burnup reactivity swing that is as much as 82.5% less than the swing of non-BP-loaded core; furthermore, the maximum beam current is 12.5 mA. The reactor characteristics of the optimized BP-loaded ADS core are also analyzed to investigate how the introduction of BP assembly influences the system. Safety parameters (such as the Doppler coefficient and the coolant void reactivity) worsen with the introduction of BP assembly, and the total minor actinide transmutation amount decreases 30–40 kg because of the moderated neutrons and changed fuel composition.

Prominent sensory involvement in a case of familial amyotrophic lateral sclerosis carrying the L8V SOD1 mutation

• We present a case of familial amyotrophic lateral sclerosis carrying the L8V SOD1 mutation with novel clinical manifestations.

Disseminated cerebral amyloid angiopathy‐related inflammation manifesting as non‐convulsive status epilepticus

Cerebral amyloid angiopathy‐related inflammation is a rare treatable encephalopathy in the elderly. Although cerebral amyloid angiopathy‐related inflammation often manifests as seizures, the details have not been well documented. We describe a 70‐year‐old man with disseminated cerebral amyloid angiopathy‐related inflammation manifesting as secondary non‐convulsive status epilepticus, whose ictal electroencephalogram showed periodic lateralized epileptiform discharges. The cerebral microbleeds were disseminated, but rather obscure in the region where the magnetic resonance imaging and electroencephalogram abnormalities were prominent. The symptoms ameliorated after the administration of corticosteroids in combination with an antiepileptic drug. Cerebral amyloid angiopathy‐related inflammation should be taken into consideration when elderly patients present with progressive mental and cognitive decline with disseminated cortical and subcortical lesions. As some cerebral amyloid angiopathy‐related inflammation patients might manifest as non‐convulsive seizure, electroencephalograms are necessary for deciding the therapeutic strategy.

J-integral evaluation for an interface crack under thermal load using digital image correlation

In this study, a method for evaluating a fracture parameter, J-integral, for an interface crack from the displacement fields under thermal deformation is developed for studying the fracture behavior of an interface crack in an actual electronic component. First, the displacement fields around an interface crack tip are measured using digital image correlation (DIC). Second, the displacement gradient and strain are determined from the displacement fields using a finite element smoothing technique on the domain of integration. Then, the stress components are determined from the strains using the elastic-plastic relations with the incremental strain theory and the each material property. Finally, the J-integral value is determined by the numerical integration on the domain of integration. The effectiveness of this evaluation method is demonstrated by applying this method to the displacement fields obtained from the elastic-plastic finite element analysis.