• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.54
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• pp.167-177
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• 2000

The problem of system reliability is very important issue in the nuclear power plant, because the failure of its system brings about extravagant economic loss, environment destruction, and quality loss. This paper therefore proposes a normalized scoring model by the qualitative factors order to evaluate the robust reliability of nuclear power plants under uncertainty. Especially, the qualitative factors including risk, functional, human error, and quality function factors for the robust justification has been also introduced. Finally, the analytical reliability and safety assessment model developed in this paper can be used in the real nuclear power plant.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.282-287
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• 1996

We. develop in this study a wavelet transform method to apply to the flux reconstruction problem in reactor analysis. When we reconstruct pinwise heterogeneous flux by iterative methods, a difficulty arises due to the near singularity of the matrix as the mesh size becomes finer. Here we suggest a wavelet transform to tower the spectral radius of the near singular matrix and thus to converge by a standard iterative scheme. We find that the spectral radios becomes smatter than one after the wavelet transform is performed on sample problems.

• Korea and Global Affairs
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• v.1 no.1
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• pp.97-114
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• 2017

This article aims for searching the clue of North Korea nuke-problem by understanding it contextually. We must see this from the beginning as many trials in settling the problem have failed. North Korea nuke-problem is related to the change of international implication as well as the domestic process of its development. At first, it started from the regime survival, which evolved with the effect of learning. During the Cold War, its development had combined the principle of 'self-defense' because of Sino-Russia conflict. Particularly, its meaning varied dramatically due to the collapse of Cold War system plus the advent of post-Cold War system. North Korea nuclear program has became a global problem based on the deterioration of North Korea's security milieu and Bush administration's policy. Therefore, the area of common solution for NK nuke-problem must be found in the context of regime survival and the change of its meaning by continual convergence effort.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1428-1438
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• 2023

A novel Fission Diffusion Synthetic Acceleration (FDSA) method is developed and implemented as a part of a hybrid neutronics method for source convergence acceleration and variance reduction in Monte Carlo (MC) criticality calculations. The acceleration of the MC calculation stems from constructing a synthetic operator and solving a low-order problem using information obtained from previous MC calculations. By applying the P₁ approximation, two correction terms, one for the scalar flux and the other for the current, can be solved in the low-order problem and applied to the transport solution. A variety of one-dimensional (1-D) and two-dimensional (2-D) numerical tests are constructed to demonstrate the performance of FDSA in comparison with the standalone MC method and the coupled MC and Coarse Mesh Finite Difference (MC-CMFD) method on both intended purposes. The comparison results show that the acceleration by a factor of 3-10 can be expected for source convergence and the reduction in MC variance is comparable to CMFD in both slab and full core geometries, although the effectiveness of such hybrid methods is limited to systems with small dominance ratios.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1199-1210
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• 2017

A new in-line method for sampling neutrons emitted in (${\alpha}$,n) reactions based on alpha particle source information has been developed for continuous-energy Monte Carlo simulations. The new method uses a continuous-slowing-down model coupled with (${\alpha}$,n) cross section data to precompute the expected neutron yield over the alpha particle lifetime. This eliminates the complexity and computational cost associated with explicit charged particle transport. When combined with an integrated alpha particle decay source sampling capability, the proposed method provides an efficient and accurate method for sampling (${\alpha}$,n) neutrons based solely on nuclide inventories in the problem, with no additional user input required. Results from several example calculations show that the proposed method reproduces the (${\alpha}$,n) neutron yields and energy spectra from reference experiments and calculations.

• Advances in Energy Research
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• v.3 no.2
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• pp.71-80
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• 2015

This paper describes nuclear energy technologies for the solution of long term energy problem with better reliability. A short overview about nuclear energy applications are explained with a basic analysis of energy. Furthermore, industrial application, space application of nuclear systems and ship propulsion in nuclear energy application are demonstrated in more detail. This report also includes some examples of the experienced nuclear power plant to identify energy production. The general purpose of the article is to understand how efficiently nuclear systems generates energy, and solve the world's increasing energy demand in our century.

• Nuclear Engineering and Technology
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• v.21 no.2
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• pp.99-110
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• 1989

The optimal control of xenon concentration in a nuclear reactor is posed as a linear quadratic regulator problem with state feedback control. Since it is not possible to measure the state variables such as xenon and iodine concentrations directly, implementation of the optimal state feedback control law requires estimation of the unmeasurable state variables. The estimation method used is based on the Luenberger observer. The set of the reactor kinetics equations is a stiff system. This singularly perturbed system arises from the interaction of slow dynamic modes (iodine and xenon concentrations) and fast dynamic modes (neutron flux, fuel and coolant temperatures). The singular perturbation technique is used to overcome this stiffness problem. The observer-based controller of the original system is effected by separate design of the observer and controller of the reduced subsystem and the fast subsystem. In particular, since in the reactor kinetics control problem analyzed in the study the fast mode dies out quickly, we need only design the observer for the reduced slow subsystem. The results of the test problems demonstrated that the state feedback control of the xenon oscillation can be accomplished efficiently and without sacrificing accuracy by using the observer combined with the singular perturbation method.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.474.1-474.1
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• 2006

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1354-1357
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• 2017

Characterization of special nuclear material may be performed using energy spectroscopy of either the neutron or gamma-ray emissions from the sample. Gamma-ray spectroscopy can be performed relatively easily using high-resolution semiconductors such as high-purity germanium. Neutron spectroscopy, by contrast, is a complex inverse problem. Here, results are presented for $^{252}Cf$ and PuBe energy spectra unfolded using a single EJ309 organic scintillator; excellent agreement is observed with the reference spectra. Neutron energy spectroscopy is also possible using a two-plane detector array, whereby time-of-flight kinematics can be used. With this system, energy spectra can also be obtained as a function of position. Spatial-dependent energy spectra are presented for neutron and gamma-ray sources that are in excellent agreement with expectations.

• 전기의세계
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• v.16 no.1
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• pp.19-28
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• 1967

Indigenous energy resources available in Korea are limited to the three major resources such as Korean anthracite, hydraulic potential and wood and straws. As reported in various reports concerning energy problem in Korea, unfortunately these three major resources are not only poor in quality but also limited in quantity. The amount of energy to be imported, which will be increased at a considerably high rate by years due to the shortage in the supply by domertic sources against the demand, is studied in the view-pint of sound and logical energy dependence upon the external sources. What would occur, if the imported energy would be exclusively limited to an energy source only, has an enough reason to be paid a significant consideration. As a result, the feasibility is discarded in favour of nuclear power plants after an extensive prospect for electric power development plan covering more than coming thirty years, i.e., up to the year of 2,000 A.D. In briefing, this paper indicates that a measures to accomodate as large amount of nuclear power plants as possible in the electric power system is not only inevitable for a sound solution of the severe energy problem with which Korea is to be confronted but also leads to the national benefit.