The insulation performance of cables removed from an actual plant was investigated in a simulated severe accident (SA) environment. The cable insulated with flame-retardant ethylene propylene diene rubber (FR-EPDM) was a safety cable in the plant. A similar FR-EPDM-insulated cable was aged artificially to the degree equivalent to what the removed cable would have been suffered. These cables were irradiated with ⁶⁰Co gamma rays at a dose rate of 10 kGy/h for 50 hours at room temperature to simulate the radiation exposure during a SA. The cables were then exposed to a steam environment for 168 hours to simulate the SA. During the steam exposure, the insulation resistance of the cables was measured continuously. As a result, the minimum insulation resistance was about 10⁸ to 10⁹ Ωm in the two cables, indicating that both have sufficient insulation performance.

This paper presents the effect of impulse voltage prestress on AC partial discharge characteristics of laminated PET films including an artificial void. The results of AC partial discharge (PD) tests shows that PD inception voltage (PDIV) largely drops after the impulse prestress irrespective of the void diameter and gap length, and later recovers to the first PDIV measured before the prestress. An attempt is made to estimate quantitatively the charge density accumulated on the void surface after the impulse voltage application causing PD from a difference in PDIV before and after the prestress. The observed effect of the prestress on the decrease and recovery of PDIV is discussed in terms of the accumulated surface charge behavior.

The PEA (Pulsed electro-acoustic) method is one of measurement techniques for space charge distributions in insulating materials, and we have improved the positional resolution of high temperature measurement. In the improvement, a thin acoustic sensor of P(VDF-TrFE) film was made using a spin coating method, and a piezoelectricity was given to it by poling procedure. Using this thin sensor, it is found that the space charge distribution was measured with a positional resolution of about 5 µm at 80℃.

In this report, the magnetic dipole moment was used to determine the need for a magnetic shield for capsule endoscopy guiding device. In addition, the index of the number of layers of MSC was examined from the evaluation of the magnetic shield characteristics of the open pail can, which is attracting attention as MSC, and the magnetic dipole moment. As a result, it became clear that the magnetic guiding device needs to be magnetically shielded at 11 Am² and above. In addition, when the shielding performance of the open pail can was evaluated, it was shown by analysis that the magnetic flux density could be reduced by up to 1.53 mT and the relative permeability was 1000. Finally, it was found that when the magnetic dipole moment of the magnetic inducer is less than 41 Am², only the open pail can is required, and when it is 41 Am² or more, the MSC needs to have two or more layers.

The Conventional electrolarynx (EL) restores the voice of people who have lost their voice, however, its voice sounds like a robot and it occupies user's one hand. Therefore, we developed a hands free wearable electrolarynx that improves the voice quality with the LPC residual wave as the vibration sound. Our device outputs the voice with a clearer formant on F3 and F4 than conventional EL does. Thus, we verified that the individuality of the voice can be expressed with our device.