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[en] The HANARO, an open-tank-in-pool type research reactor of a 30MWth power in Korea, has been operating for 10 years since its initial criticality in February of 1995. The reactor trip or shutdown is accomplished by four shutoff units by insertion of the shutoff rods. The shutoff rod(SOR) is actuated by a directly linked hydraulic cylinder on the reactor chimney, which is pressurized by a hydraulic pump. The rod is released to drop by gravity, when triplicate solenoid valves ('dump valves') are opened to vent the cylinder. This paper summarizes the history of the performance, maintenance, drop cycles and the life extension program for the shutoff units
[en] 'Full text': The published data for rise of buoyant plumes are compared with about half of the thirty formulas now in the literature. Rise in stable air can be accurately predicted, given the buoyancy flux of the source, F, a stability Parameter proportional to the mean potential temperature gradient, s , and the mean wind speed, u. The Morton, Taylor and Turner theory quite successfully describes plume behavior when there is negligible wind, predicting that Δh = 5 F1/4s-3/8. When the plume is bent over in a wind the formula of Briggs best predicts the rise, Δh 2.5(F/us)1/3. Rise in an adiabatic or an unstably stratified atmosphere is not nearly as well known. All present observations of plume paths are fit fairly well by the 'x2/3' law, where x is the distance downwind of the stack. No 'final' rises in this case have been observed, and no data go downwind as far as the distance of greatest concern, i.e. that at which maximum ground concentration occurs. In view of these difficulties it is possible to recommend only an empirical fit to present data, a 'minimum expected plume rise.' The complete report will be an ORNL-NSIC document, 1967. (author)
[en] PurposeTo describe a modified endovascular technique for complete revascularization of visceral and renal arteries in symptomatic pararenal aortic aneurysm (PRAA).TechniqueArterial access was surgically established in both common femoral arteries (CFAs) and the left subclavian artery (LSA). Revascularization of the left renal artery, the celiac trunk, and the superior mesenteric artery was performed through one single sheath via the LSA. Suitable covered stents were put in the aortic branches but not deployed. The right renal artery was accessed over the left CFA. Due to the longitudinal extension of the presented aneurysm two stent-grafts were introduced via the right CFA. After deploying the aortic stent-grafts, all covered stents in the side branches were deployed consecutively with a minimum overlap of 5 mm over the cranial and caudal stent-graft edges. Simultaneous ballooning was performed to fully expand all stent-grafts and warranty patency. Conclusion: This is the first report in the literature of chimney grafting in PRAA for complete revascularization of visceral and renal branches by using more than two covered stents introduced from one side through one single sheath. However this technique is modified, it should be used only in bailout situations when branched stent-grafts are not available and/or surgery is not suitable.
[en] The in-chimney bracket structures will be installed on the upper part of chimney, which holds the capsule extension pipes in upper one-third of length. For evaluating the seismic effects on the capsules and related reactor structures by installation of the in-chimney bracket, an ANSYS analysis model is developed, and the dynamic characteristics are analyzed. The seismic response analyses of in-chimney bracket and related reactor structures of HANARO under the design earthquake response spectrum loads of SSE(0.2g) are performed. The several candidated designs of the capsule extension pipes and support spring stiffness to meet the displacement limit of the flow tubes in core region are proposed
[en] In HANARO are there provided three hexagonal irradiation holes (CT, IR1 and IR2) in the central region of the core while four circular irradiation holes (OR3 ∼ OR6) in the outer core. There exist two types of irradiation facilities: uninstrumented or instrumented. The uninstrumented irradiation facility is little influenced by the coolant flow. But the dynamic behavior by the flow-induced vibration (FIV) and seismic loads is expected to largely occur in case of the instrumented test facility due to the long guide tube to protect the instrumentation cables. To suppress this dynamic behavior of the facility, the in-chimney bracket was designed. As a supplementary supporting structure for irradiation facility, this bracket will hold guide tubes whose holding position of the instrumented facility in CT or IR is the middle part of the instrumented facility between the hole spider and the robot arm already provided in the reactor pool liner. On the while, the bracket will grip the upper part of the guide tube when it is applied to hold the instrumented facility loaded in OR sites. Therefore it is believed that the irradiation test can be successfully conducted since this bracket can reduce the FIV and dynamic response to seismic load as well. In new in-chimney bracket, IR1 is reserved for IPS(In-Pile Section) so only CT/IR2 guide tubes are supported by CT/IR clamp units and the shape of In-chimney bracket is redesigned. For evaluating the structural integrity on the new in-chimney bracket and related reactor structures, ANSYS finite element analysis model is developed and the dynamic characteristics are analyzed. The seismic response analyses of new in-chimney bracket and related reactor structures of HANARO under the design earthquake response spectrum loads of OBE(0.1g) and SSE(0.2g) are performed. The response shows that the stress values for main points on the reactor structures and the new in-chimney bracket for seismic loads are within the ASME Code limits. It is also confirmed that the fatigue usage factor is much less than 1.0. Therefore any damage on structural integrity is not expected when a new in-chimney bracket is installed in the upper part of the reactor chimney
[en] This paper describes the rise of strongly radioactive plumes. If a portion of the gases in a plume is radioactive, heat will be supplied continuously to each plume element by radioactive decay, producing buoyant rise. A plume could also acquire buoyancy through chemical reactions, thermal radiation effects, or latent heat exchange. This paper considers the plume rise that results from such buoyancy addition at a uniform rate.
[en] This article introduces the chimney noble gas sampling measurement of TNPS. Through comparing and evaluating the data of the two sampling systems about noble gas, it comes to a conclusion that both the results are basically consistent and reliable; and put forward improvement suggestions to the online gas spectrometer system. (authors)
[en] HANARO has a vertical hole for a cold neutron source, the CN hole, which was considerably deformed during manufacturing due to the welding on the horizontal beam tube. The shape of the CN hole was measured and analyzed for the optimal design of the vacuum chamber of the cold neutron research facility. The installation concept and realization plan were proposed based on the shape of the CN hole
[en] The 2016 August 24th, Mw6.0 Amatrice (Central Italy) normal faulting earthquake produced a remarkable number of Earthquake-Rotated Objects (EROs) that affected chimneys, as well as pillars and capitals on gates and walls. In this paper we present the EROs dataset, and perform some qualitative analyses to evaluate if specific geological and seismological features such as intensity, epicentral distance, potential amplification of the seismic shaking at the site, heterogeneities of the rupture on the fault and directivity effects, and peak ground accelerations, favoured the distribution of EROs observed after the earthquake. A first important outcome is that the distribution of the EROs of Amatrice 2016 mimics the general pattern of damage, and that EROs occurrence should be regarded as a diagnostic element of intensity degrees lower than those presently established by formalized scales. We also find that site factors, namely the surface geology and the local amplification, are the most significant contributors to the EROs occurrence. In addition, we find that the position respect to the fault can enhance the occurrence of local rotations. The distinctive features characterizing the 2016 EROs dataset resemble and substantiate the most important findings produced by previous studies carried out following the 2009 L’Aquila and 2012 Emilia seismic sequences, and allow to calibrate the empirical relations on the EROs distribution presented in the world Catalog of Earthquake-Rotated Objects.
[en] For the operation and maintenance works of In- Chimney in HANARO, the bottom of Y-piece supporting the IPS had been cut-off by 100mm. This modification needs for the additional finite element calculation following an earlier study, which showed the seismic analysis