[en] Purpose: To substitute the water feeding function to a fuel pool with a high pressure reactor core spray pump by utilizing a minimum flow rate by-pass pipeway in a high pressure reactor core spray device. Constitution: Water in a condensator tank is transferred from the condensator tank by a high pressure reactor core spray pump and injected by way of an electrically operated injection valve from a spray spurger in the pressure vessel into the reactor. The exhaust pipeway of the pump is branched and returned by way of the electrically operated valve to the condensator tank to form a minimum flow rate by-pass pipeway for protecting the pump against overheat. A pipeway is branched from the by-pass pipeway and connected from the orifice by way of the electrically operated valve to a spent fuel pool. This enables to supply water for the condensator tank upon failure of the spent fuel pool, as well as to save the additional pump for feeding water to the fuel pool which has been required so far. (Kawakami, Y.)

[en] Purpose: At the time of starting from the low-temperature condition in a device for handling a high temperature fluid, to evade an abrupt temperature rise of the device and to increase slowly the temperature thereof. Constitution: Bypass pipes are provided at the suction side of a circulating pump and at the outlet side of a regenerated heat exchanger, and valves are provided in parallel to the branched pipes. The downstream sides of the valves are converged and connected to the reactor water supply source. At the time of starting, a closed loop is functioned to a circulation system consisting of circulation pump-regenerated heat exchanger-non-regenerated heat exchanger-filtration desalting device-regenerated heat exchanger-circulation pump, and circulation water of the closed loop is caused to gradually flow to the reactor under surveilance of a thermometer. High temperature water of the reactor is caused gradually to flow into the closed loop, and the temperature of the closed loop is slowly raised. (Aizawa, K.)

[en] The purpose of this study was to test the usefulness of thallium-201 (Tl-201) thyroid scintigraphy in the detection of thyroid malignancies. Early and delayed Tl-201 scintigraphy was done in 135 patients with a clinically solitary thyroid nodule. There were 64 benign tumors and 71 malignant tumors. Scintigraphy was done 10 minutes (early scan) and 2 hours (delayed scan) after the administration of Tl-201. With a combination of early and delayed Tl-201 scintigraphy, sensitivity was 57.7% and specificity was 81.2%. Therefore, Tl-201 scintigraphy is of limited value for the detection of thyroid malignancies. (author)

[en] Fourteen cases of benign paroxysmal positional vertigo (BPPV) were studied with cervical circulation using DSA and Doppler. DSA study showed 7 abnormal cases out of 10 cases of BPPV. The abnormal findings included 5 cases of stenosis and 5 cases of coiling and kinking in cervical vertebral arteries. Doppler study showed that vertebral a. and also carotid a. had low volume and high laterality of cervical blood circulation in parameter of flow and velocity. These findings suggest the cervical circulation disorder was one of background factors in pathogenesis of BPPV. (author)

[en] Post-installed adhesive anchor bolts are commonly used on all types projects, from standard buildings to bridges and nuclear power plants. They are exposed to varying and diverse environmental conditions which are significant successfully to make connections to concrete structures for many years. With the failure of adhesive anchors in the Boston I-90 Tunnel Project, the use of these types of anchors has been called into question in America. On the other hand, also in Japan, a section of the SASAGO tunnel’s suspended concrete ceiling with adhesive anchor bolts became detached from the tunnel roof and fell onto the vehicles, 2012. In order to maintain the safety and reliability of concrete structures such as buildings or bridges on higher level over a long period time, we developed a new non-destructive inspection system of adhesive anchor bolts based on hammering tests using AE (acoustic emission) sensor. By adjusting the amount of resin of adhesive anchors, the model bolts with poor construction quality were made on concrete blocks and finite element analysis was carried out to evaluate performance of this inspection system. (author)

[en] Post-installed adhesive anchor bolts are commonly used on all types projects, ranging from standard buildings to bridges and nuclear power plants. They are faster to install, generally considered to be stronger, more flexible, easier to use and more reliable in majority of applications at ambient temperatures. They are exposed to varying and diverse environmental conditions which are significant successfully to make connections to concrete structures for many years. With the failure of adhesive anchors in the Boston I-90 Tunnel Project, the use of these types of anchors has been called into question in America. On the other hand, also in Japan, a section of the Sasago tunnel's suspended concrete ceiling with adhesive anchor bolts became detached from the tunnel roof and fell onto the vehicles, 2012. In order to maintain the safety and reliability of concrete structures such as nuclear plants on higher level over a long period time, we developed a new non-destructive inspection system of adhesive anchor bolts based on hammering tests using AE (acoustic emission) sensor. By adjusting the amount of resin of adhesive anchors, the mockup anchors with poor construction quality was made on concrete blocks and mockup experiment was carried out to evaluate performance of this inspection system. As a result of the mockup experiment, peak frequency of signal obtained from AE sensor shifted to lower frequency as the amount of resin decreased. In this mockup experiment, it was confirmed that our developed inspection system based on hammering tests using AE sensor had a large potential to evaluate adhesive anchor bolts. (author)

[en] Digital hammering inspection system with AE (Acoustic Emission) sensor has been developed and the effects of state, stiffness, etc. on the natural frequency of metal and concrete objects to be inspected were evaluated in terms of improper installations and age-related degradations. The system has been widely applied to social infrastructural diagnosis including expressways (West Nippon Expressway Company Limited, NEXCO-WEST), nuclear power plants (ex. Chubu Electric Power Co., Inc.), reprocessing plant of spent nuclear fuel (Japan Nuclear Fuel Limited) and a successful on-site trial of a new technology of i-Construction led by MLIT (the Ministry of Land, Infrastructure, Transport and Tourism). (author)

[en] We have developed a non-destructive inspection technique using the AE (acoustic emission) sensor. It is intended to be non-destructive evaluation in soundness of the adhesion anchor is installed in a nuclear power plant. We analyzed the Eigen frequency of the adhesive anchor measured by the AE sensor using a finite element method. Results of the analysis of the Eigen frequency, the change in Eigen frequency could be confirmed between the adhesive anchor which simulates the Peeling of the resin by aging degradation and defective workmanship and Healthy adhesive anchor. Moreover, the result of comparison examination with an experimental result is reported. (author)

[en] Post-installed adhesive anchor bolts are commonly used on all types projects, from standard buildings to bridges and nuclear power plants. They are exposed to varying and diverse environmental conditions which are significant successfully to make connections to concrete structures for many years. In order to maintain the safety and reliability of concrete structures such as buildings or bridges on higher level over a long period time, we developed a new non-destructive inspection system of adhesive anchor bolts based on hammering tests using AE (acoustic emission) sensor. It was confirmed that our developed inspection system based on hammering tests using AE sensor had a large potential to evaluate adhesive anchor bolts. (author)

[en] We have developed Check Valve Inspection System using acoustic emission sensor and ultrasonic sensor, to examine degradation and detailed motion (Full open, Tapping, Oscillation, etc.) of the swing check valve. This inspection system was applied check valves in the seawater system line of domestic nuclear power plants. The examination was carried out before and after replacing the check valve. Comparing the results of the inspection system and the results of overhaul, effectiveness of this system has been shown. (author)