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[en] An automatic controller that uses the model predictive control (MPC) method is being developed for automatic load follow operation. As described in Ref. a system identification method is important in the MPC method because MPC is based on a system model produced by system identification. There are many models and methods of system identification. In this study, AutoRegressive eXogenous (ARX) model was selected from among them, and the recursive least square (RLS) method and least square (LS) method associated with this model are used in a comparative performance analysis
[en] Hydro-Quebec has been using CFD to analyze the performance of its existing turbines for many years. Most of those analyses are based on the measurement of a single runner blade. However, due to manufacturing techniques, in-situ modifications or repairs, there are often small differences between individual blades of the same runner. The impact of this non uniformity was not known thus far and was often assumed to be negligible given the size of the runner. This paper highlights the impact of such differences by presenting the CFD analysis of various blades measured on the same runner. Two different geometries are used for demonstration: the AxialT model propeller and a 50-MW Francis turbine. In both cases, about 50% of the blades could not be considered as representative of the whole turbine and using them could lead to wrong conclusions regarding the turbine performance.
[en] The purpose of this work is to establish the proficiency testing schemes of a fuel assembly for nonstandard test method case. As the nuclear regulatory guide, 'the testing and inspections to be performed to verify the design characteristics of the fuel system components, including clad integrity, dimensions, fuel enrichment, burnable poison concentration, absorber composition, and characteristics of the fuel, absorber, and poison pellets, should be described. ∼'. In this guide, the fuel assembly test method is as that, the lateral and axial stiffness, lateral vibration, lateral and axial impact and the rotational stiffness test. These method cases are very important for the license service and providing some input data for the accident analysis model of FA. Therefore, all of these tests have to be executed as the authorized standard, for example, Korea Laboratory Accreditation Scheme (KOLAS). Unfortunately, the performance tests of a FA did not certified by the KOLAS. In order to receive the authorized test scheme, the proficiency testing schemes is most important item. For non-standard test case, the most of these tests be normally executed through the inter-laboratory comparisons. However, there is no standard, no certified reference material (CRM) for pressurized water reactor (PWR) fuel assembly. In this case, the most important point is that how to verify the validity of the performance test method of a fuel. Therefore, the inter-personnel testing scheme is proposed for this. For the proficiency testing of a fuel assembly performance test, the lateral bending test of a fuel assembly (FA) is executed using FAMeCT. The FAMeCT is a tester of a versatile function for a mechanical characterization of an actual size FA. Because of the absence of the CRM, the t-test method was selected. Null and alternative hypotheses were assumed and then t-value was evaluated as these hypotheses
[en] Environmental sampling has considered a part of verification tool on North Korea nuclear activities since 2006. Collected samples undergo gamma screening at the Korea Institute of Nuclear Nonproliferation and Control (KINAC) before detailed analysis is carried out. The Compton Suppression System (CSS) is widely used for screening because of its high resolution. KINAC had designed the CSS with three secondary detectors. These detectors are designed to collect and subtract the Compton scattered events. This article will discuss the performance of the each secondary detector and the effect of the source location to the resolution of the whole system
[en] A good performance of high resolution nuclear spectrometry systems, at high pulse rates, demands restoration of baseline between pulses, in order to remove rate dependent baseline shifts. This restoration is performed by circuits named baseline restorers (BLRs) which also remove low frequency noise, such as power supply hum and detector microphonics. This paper presents simple circuits for baseline restoration based on a commercial current conveyor (CCII01). Tests were performed, on two circuits, with periodic trapezoidal shaped pulses in order to measure the baseline restoration for several pulse rates and restorer duty cycles. For the current conveyor based Robinson restorer, the peak shift was less than 10 mV, for duty cycles up to 60%, at high pulse rates. Duty cycles up to 80% were also tested, being the maximum peak shift 21 mV. The peak shift for the current conveyor based Grubic restorer was also measured. The maximum value found was 30 mV at 82% duty cycle. Keeping the duty cycle below 60% improves greatly the restorer performance. The ability of both baseline restorer architectures to reject low frequency modulation is also measured, with good results on both circuits