[en] During the normal operation of HANARO, 30 MW open-pool type research reactor, several radionuclides are dispersed in pool or coolant water. The nuclides in the water are generated by activations of coolant, dissolved substances and corrosion products. In addition, there are several fission products caused by uranium contamination on fuel cladding surface. The radionuclides disappear by radioactive decay, release out of the water, and they are also eliminated by the ion exchange resin in the coolant purification system. Thus, the information on its efficiency to remove the nuclides from the coolant is necessary to estimate the radiological effect of a research reactor. In this work, the efficiency is measured by the gamma-ray spectroscopy for the coolant of HANARO

[en] To compare the findings of early periventricular leukomalacia on MR imaging and on US. MR imaging was performed in 17 neonates in whom well-demarcated increased periventricular echogenicity was seen on sonography. One more patient was included during the same period because MR imaging of this patient showed a periventricular lesion not suspected on previous US. Initial sonography was performed within 6 days of birth and was followed up between one week and one month later. MR images were obtained within the first month of life. Twelve of 17 neonates showed abnormal periventricular signal intensities on MR imaging. Follow up sonography revealed cystic changes in two cases and heterogeneous hyperechogenicities in three. All patients except the two with cystic changes showed normal periventricular echogenicity on final sonography. On MR imaging, 11 cases showed multifocal periventricular increased signals on T1-weighted images, and two showed mainly decreased signals representing cysts. Positive findings were more evident on T1-weighted than on T2-weighted images. On T1-weighted imaging, the characteristic finding of early periventricular leukomalacia was multifocal periventricular hyper or hypointensities, and hyperintense lesions were more common than hypointense. In the diagnosis of early noncystic periventricular leukomalacia, MR imaging was more objective than US

[en] The species and concentrations of the radionuclide in the primary coolant of HANARO were analyzed by using the gamma-ray spectroscopy. The full-energy peak efficiency for the volume source was calibrated as a function of the photon energy for an HPGe detector. The primary coolant of HANARO was picked at the primary coolant purification system, and the water at the upper part of the reactor pool was taken at about 20 cm under the pool surface. In the primary coolant, the concentrations of Na-24, Mg-27 and Al-28 were much higher than those of other nuclide, and they were in 1-6 x 10⁶ Bq/liter. Their origins were radiative reactions of aluminium used as the structure material and cladding of the nuclear fuel. The concentrations of Xe-138 and Xe-133 were relatively higher than those of other fission fragments. The source of the fission fragments in the coolant was the surface contamination of the nuclear fuel by uranium. Ar-41, Ce-141, Na-24 and Xe-133 were detected in the water at the upper part of the reactor pool. Na-24 was the main source of the pool top radiation level, and Xe-133 and Ar-41 were the main gaseous radionuclide released through the reactor pool surface

[en] To evaluate the US and CT findings of abdominal wall eddometrioma. We respectively reviewed nine patients with abdominal wall masses diagnosed as endometrioma during a recent three-year period. Both US and CT scans were performed in six cases, only ultrasound in one, and only CT scans in two. The location, size, shape, margin, internal echo or density, enhancement patterns, and relation to adjacent masses, as seen on US and CT images, were reviewed. All patients had a previous history of deliveries by caesarian section. All masses were 2-4.5cm in size ; five were located in subcutaneous layers and four in muscle layers. In all cases, sonographic findings were low echoic masses with irregular margins(7/7). Internal echotextures were inhomogeneous in five cases and homogeneous in two. On CT, masses in subcutaneous layers(5/8) showed speculated margins and linear enhancement of the rectus muscle fascia. In cases of lesion located in muscle(3/8), slight thickening of the rectus muscle was visible on precontrast CT scans, but on postcontrast CT scans, well-defined enhancing masses, separate from the rectus muscle were seen. When patients with a previous history of caesarian section present palpable abdominal wall masses, with cyclic pain, sonographic findings of a low echoic mass separated from the internal organs, and CT findings of a strongly enhanced mass are useful for the diagnosis of endometrioma

[en] The species and concentrations of the radionuclide in the primary coolant of HANARO were analyzed by using the gamma ray spectroscopy. The full energy peak efficiency for the volume source was calibrated as function of the photon energy for an HRGs detector. The primary coolant of HANARO was picked at the primary coolant purification system, and the water at the upper part of the reactor pool was taken at about 20cm under the pool surface. In the primary coolant, the concentrations of Na-24, Mg-27 and Al-28 were much higher than those of other nuclide, and they were in 1∼6x10'6'Bq/liter. Their origins were radiative reactions of aluminium used as the structure material and cladding of the nuclear fuel. The concentrations of Xe-138 and Xe-133 were relatively higher than those of other fission fragments. The source of the fission fragments in the coolant was the surface contamination of the nuclear fuel by uranium. Ar-41, Ce-141, Na-24 and Xe-133 were detected in the water at the upper part of the reactor pool. Na-24 was the main source of the pool top radiation level, and Xe-133 and Ar-41 were the main gaseous radionuclide released through the reactor pool surface

[en] Neutron transmutation doping (NTD) for producing Ntype silicon is based on the conversion of the Si-30 isotope into phosphorus atom by the absorption of neutron. This method can produce silicon semiconductors with extremely uniform dopant distributions. The NTD is one of the rare cases in the research reactor utilization providing direct industrial applications. HANARO, a 30 MW research reactor, has two vertical holes in the heavy water reflector region for the NTD - NTD1 and NTD2 of which the diameters are 22 and 18 cm, respectively. It has been confirmed that the two holes are very good for the NTD from the viewpoints of neutron quality and size. The commercial NTD service for 5 in. silicon ingot has been going on at the NTD2 hole, and an additional 6 in. irradiation device at the NTD2 and a 6 and 8 in. irradiation facility using the NTD1 hole are under development. In the several procedures of NTD service, the workers are occupationally exposed by radiation, mainly, gammarays. In this work, gamma-ray dose rates at the surfaces of the irradiated materials in NTD service are investigated in order to predict the dose rate of the NTD workers

[en] The species and concentrations of the radionuclide in the primary coolant of HANARO were analyzed by using the gamma-ray spectroscopy. The full-energy peak efficiency for the volume source was calibrated as a function of the photon energy for an HPGe detector. The primary coolant of HANARO was picked at the primary coolant purification system, and the water at the upper part of the reactor pool was taken at about 20 cm under the pool surface. In the primary coolant, the concentrations of Na-24, Mg-27 and Al-28 were much higher than those of other nuclide, and they were in 1 - 6x10⁶ Bq/liter. Their origins were radiative reactions of aluminium used as the structure material and cladding of the nuclear fuel. The concentrations of Xe-138 and Xe-133 were relatively higher than those of other fission fragments. The source of the fission fragments in the coolant was the surface contamination of the nuclear fuel by uranium. Ar-41, Ce-141, Na-24 and Xe-133 were detected in the water at the upper part of the reactor pool. Na-24 was the main source of the pool top radiation level, and Xe-133 and Ar-41 were the main gaseous radionuclide released through the reactor pool surface. (author)

[en] Neutron transmutation doping (NTD) for producing N-type silicon is based on the conversion of the Si-30 isotope into phosphorus atom by the absorption of neutron. This method can produce silicon semiconductors with extremely uniform dopant distributions. HANARO, a 30 MW research reactor, has two vertical holes in the heavy water reflector region for the NTD - NTD1 and NTD2 of which the diameters are 22 and 18 cm, respectively. It has been confirmed that the two holes are very good for the NTD from the viewpoints of neutron quality and size. And now, commercial NTD service for 5 inch silicon ingot is going on at NTD2 hole, and the irradiation facility for 6 inch ingot is being developed for the NTD1 hole. Uniform irradiation in the ingot radially as well as longitudinally is the prime target of the irradiation device design. The neutron screen method was chosen in HANARO for the uniform irradiation. From the previous study, the optimum neutron screen was searched so as to give an axial flux uniformity within ±2%. The radial uniformity of the resistivity can be represented by RRG(radial resistivity gradient), RRG=ρ_max-ρ_min/ρ_min where ρ_min and ρ_max are the minimum and maximum resistivity in a silicon wafer, respectively. Generally, the NTD customer demands that the RRG of an irradiated NTD silicon should be lower than 4∼5% for 5 inch ingot. The radial uniformity cannot be perfect because the neutron flux of the inner part of silicon is slightly lower than the periphery due to the neutron attenuation by silicon and the initial resistivity distribution. In this work, we checked the radial uniformity of the neutron irradiation for 5 and 6 inch ingots with calculation and experiment

[en] HANARO achieved first criticality in 1995. In this report, the reactor trip and unanticipated operational occurrences in HANARO from 2006 to 2010 are described and analysed. Most of the reactor trip and unanticipated operational occurrences, are caused by control rod trouble, leakage in the primary and secondary cooling system, blackout, abnormal of FTL(Fuel Test Loop) and CNS(Cold Neutron Source) system. Particularly most of reactor trips occurred in 2009 and 2010, due to the FTL and CNS commissioning. This report can be used for the operator education and as reference of reactor operation to prevent recurrence of the similar cases

[en] To evaluate the effect of plugging the biopsy tract in rabbit liver and the pathologic changes caused by plugging materials. Thirty-two New Zealand White rabbits were divided into four groups (eight rabbits in each) and compared with one another. They were labeled group A (control), B (gelfoam), C (fibrin sealant) or D (NBCA). the liver was exposed and biopsied with an 18G disposable biopsy gun. The inner Tru-cut needle was withdrawn and plugging was undertaken through the outer cannula of the biopsy gun. Bleeding times of each material were compared. The rabbits were sacrificed and pathologically evaluated for 17 days