[en] The loss coefficient of the butterfly valve which allows partial opening of the valve at closed position and is applicable to the small-sized pipe system with the diameter of 1 inch was measured for the variation of the valve disk blockage ratio. Two different types of the valve disk configuration to adjust the blockage ratio were considered. One was the solid type valve disk of which the diameter was changed into the smaller size rather than the pipe diameter, and the other was the perforate type valve disk on which some holes were perforated. The results from two types of valve disk were compared to identify their characteristics in the loss coefficient distributions. The loss coefficient and the controllable angle of the valve disk were decreased exponentially with the decrease of the blockage ratio. In addition, the perforate valve disk had the effect on the higher loss coefficient rather than the solid type valve disk

[en] Current management of renal angiomyolipomas (AMLs) include observation, transcatheter embolization and partial or total nephrectomy. Patients symptoms and size of the lesion are the determinants for the choice of the treatment. In general symptomatic or greater than 8 cm masses require intervention. A retrospective study of five patients presented with symptomatic lesions and treated with selective transcatheter embolization, over a 3 year period was performed in our hospital. A total of eight embolizations were performed, all on an emergency basis due to retroperitoneal bleeding or significant hematuria. Surgical intervention was necessary in one case, due to massive rebleeding on the fourth post-procedural day. Two patients rebled within 6 months and 2 years respectively, and were managed successfully with additional embolization. The remaining two patients are still asymptomatic 26 and 18 months after the successful initial result. Experience with this procedure is reported on with emphasis to the clinical outcome. It is believed that selective arterial embolization should be the standard initial therapy for symptomatic renal AMLs

[en] The normal shutdown and maintenance period of a nuclear power plant can be remarkably shortened when the examination and maintenance works in steam generator tubes are simultaneously carried out with refueling job. There are nozzle dams to block the coolant flow from reactor to steam generator. Workers are reluctant to install nozzle dam because of the high radiation exposure and the limited working space in steam generator. Moreover, the heavy weight of present nozzle dam makes its installation and removal works much difficult. In this paper, a lighter KAERI nozzle dam with increased flexural rigidity-to-weight was designed and manufactured by changing the structure design of the present nozzle dam and by selecting new material, carbon fiber-reinforced plastic. 4 figs., 6 tabs., 13 refs. (Author)

[en] Purpose: To determine the added value of multidetector computed tomography (MDCT)-assisted virtual bronchoscopy (VB) to axial MDCT and multiplanar reformatted (MPR) imaging with respect to conventional bronchoscopy in the evaluation of children with suspected foreign-body aspiration (FBA). Material and Methods: Twenty-one consecutive children (14 male, seven female, age 8 months-7 years, mean age 3.5 years) presenting with the suspicion of FBA were examined with 16-slice MDCT using 100-120 kV, 30-50 mA, 1-mm section thickness, 1.2 pitch ratio, and 0.6-1.0-mm reconstruction interval. Before CT examinations, chest radiographies were also obtained in all cases. VB and MPR imaging were carried out after MDCT examinations. Results: Nine foreign bodies were identified by gold-standard conventional bronchoscopy. VB, thin-section axial MDCT, and MPR images identified eight of nine foreign bodies. CT scans with MPR images and VB did not reveal a chronic foreign body; and, in one patient, endobronchial mucous was diagnosed as the foreign body. The sensitivity, specificity, and accuracy of thin-section axial MDCT and MPR images alone in the diagnosis of FBA were 88.9%, 91.7%, and 90.5%, respectively. Results were the same as those obtained when VB was also included. Conclusion: MDCT with VB and axial/MPR images provide equally valuable information in children with suspected foreign-body aspiration and prevent unnecessary conventional bronchoscopic examinations. However, VB increases total examination time and cost, and it does not provide additional information over MPR images in the evaluation of foreign-body aspiration

[en] The present paper demonstrates nodalization analysis results obtained in application of the MATRA-LMR/FB to channel blockage accidents for a SFR (Sodium cooled Fast Reactor), KALIMER-150. In the earlier study, a uniform node size over the total sub-channel length in a subassembly was used. The study was carried out not only for the radially different positions, i.e. central, medium between the center and the duct wall, and edge sub-channels in the assembly, but also for larger blockage sizes larger than 6 sub-channels, the blockage size of which was classified into a DBE(Design Basis Event) in the KALIMER-150 design. The present investigation focuses mainly on the identification of conservatism as well as consistency in the analyses of the maximum coolant temperature for the 6 sub-channels blockage accidents

[en] This opening and closing device is of the type which employs a casing inside the duct along the fluid path. It is provided with an opening through which the fluid flows and a joint with a closing clapper controlled from the outside enabling the fluid flow to be regulated. It is characterized by the fact that the casing is provided with a lateral opening with respect to the fluid flow direction, the size of this opening being sufficiently large to allow the assembly with its closing clapper to be introduced and withdrawn

[en] Material corrosion problem has been studied worldwide. The key element from surroundings affecting LBE corrosion is oxygen because the passive oxide formation on the metal surface is the decisive factor. Too low oxygen contents cause mass dissolution of metal substrate into LBE, but too much oxygen contents will be resulted in the coolant channel blockage by oxidation of Pb or Bi, and the porous oxide formation, which is not dense enough to protect the base metal Thus oxygen contents in LBE as well as oxygen partial pressure in cover gas must be monitored and controlled within appropriate value, typically about 10-6wt%. Generally YSZ (Yttria Stabilized Zirconia) tube or membrane is used to measure the oxygen activity, which acts as a good oxygen ion conductor. Theoretically YSZ membrane can measure the oxygen partial pressure down to 10-30 atm or less. But current oxygen sensors have several problems such as temperature hysteresis while operation, short lifetime, and leakage of ambient air into sensor. We developed an oxygen sensor to improve the leakage characteristics by applying new joining technology between YSZ ceramic and stainless steel metal structure. Various metal/oxide references were also tested

[en] Pipeline pigs are devices that are inserted into and travel throughout the length of a pipeline driven by a product flow. They are used for pipeline cleaning, pipeline protection and flow assurance in the oil, gas and other process industries. During a pigging process to clean a pipeline transporting refined petroleum oil from Buipe to Bolgatanga both in the Northern part of Ghana, the movement of the pig was obstructed leading to a blockage somewhere in the pipeline. Based on information from a pig signaler, radiographic inspections were carried on a portion of the pipeline to locate the exact position of the pig. The radiographs obtained revealed that the pig was located 50cm from a reference point and the battery component was disjointed

[en] The authors analyzed the indications, techniques, results, and complications of 96 percutaneous nephrostomy procedures performed in 60 pediatric patients between 1977 and 1988. Ninety-six attempts resulted in 93 successful catheter insertions (97%)in 39 male and 21 female patients, aged 1 day to 17 years. Bilateral catheters were placed in six patients. Obstructive uropathy was the most common indication (two renal transplants and 16 failed pyeloplasties or ureteral reimplants included). Treatment of stones required intervention in nine patients. Further dilation of the percutaneous track (16-28-F size) was necessary in seven patients (removal of foreign body in one, resection of polyp in one, endopyelotomy in two, and lithotripsy in three). The Seldinger technique was used in 15 of 93 successful catheter placements, including all cases requiring track dilation for endorenal manipulations. The Trocar technique was used in 78 successful and three failed placement attempts. Fluoroscopy was employed for guidance. No complications requiring surgery, transfusion, or angiographic embolization were encountered

[en] Sump screen issue is a concern for all PWRs. The background of sump screen issue is introduced. The development progress and current status of sump screen downstream effect are retrospected and the potential resolution options are analyzed. (authors)