Showing papers in "Annals of Nuclear Energy in 2007"

TL;DR: The issues related to the consistent qualification of coupled code systems as well as their application to different types of LWR transients are presented and the advances in numerical and computation techniques for coupled code simulations are summarized with outlining remaining challenges.

TL;DR: In this paper, the results obtained using one-dimensional and three-dimensional computational fluid-dynamic codes for the prediction of the dynamic behaviour observed in experiments carried out in a single-phase natural circulation apparatus were discussed.

TL;DR: In this article, the development of spatial dynamics code for molten salt reactors (MSRs) is reported, which is based on the light water reactor code DYN3D and it allows transients simulation by 3D neutronics and parallel channel thermal-hydraulics.

TL;DR: The TRIGA accelerator-driven experiment is a milestone in the roadmap towards the demonstration of the transmutation of nuclear waste in accelerator driven systems (ADSs) as mentioned in this paper, which is designed in such a way as to couple the different components of an ADS in a realistic environment by using an existing critical reactor adapted to the experiment's objectives, at significant power levels.

TL;DR: The results based on support vector regression machine learning confirm that this approach provides a framework for general, accurate and computationally acceptable multi-layer buildup factor model.

TL;DR: In this article, the authors used the Monte Carlo N-Particle (MCNP) code and a set of neutron cross-section data to develop an accurate three-dimensional computational model of the Nigeria Research Reactor-1 (NIRR-1).

TL;DR: In this paper, the neutronic calculation of the nuclear parameters (neutron spectrum, displacement per atom (DPA), gas production, tritium breeding ratio (TBR), nuclear heating) for structural materials in the first wall and fuel clad (made of ferritic/martensitic steels, vanadium alloy, silicon carbide, copper alloy, and stainless steel) of an experimental hybrid reactor using the most current Monte Carlo Neutron-Particle Transport code MCNP5 1.4.

TL;DR: In this article, the authors used the high brilliance electron beam from a superconducting LINAC to produce various secondary beams with a pulse width of less than 10ps, which allowed for a neutron energy resolution of better than 1% for neutron energies between E n = 50 keV and 5 MeV.

TL;DR: In this article, the authors have developed an efficient solution method for the calculation of neutron importance function in fissionable assemblies for all criticality conditions, based on Monte Carlo calculations.

TL;DR: In this article, large eddy simulation results of a subchannel of a rod bundle with triangular rod arrangement are presented, which have been carried out using the lattice Boltzmann method.

TL;DR: In this article, an extended reduced order model is presented and applied to analyze global and regional oscillations in BWRs and stability and semianalytical bifurcation analyses are performed using this model in conjunction with the BIFDD to determine the stability limits for both in-phase and out-of-phase oscillation modes.

TL;DR: In this paper, an analysis of the hydrogen and steam behavior during a total loss of feed water (LOFW) accident in the APR1400 containment has been conducted by using the computational fluid dynamics (CFD) code GASFLOW.

TL;DR: In this article, the CANDLE burnup strategy is applied to small (30MWth) block-type high temperature gas-cooled reactors (HTGRs) with thorium fuel.

TL;DR: In this article, the authors developed a dynamic model for the thermal-hydraulic analysis of a MTR research reactor during a reactivity insertion accident (RIA), which is validated by safety-related benchmark calculation for MTR-type reactors of IAEA 10MW generic reactor for both slow and fast reactivity insert transients.

TL;DR: Adaptive matrix formation (AMF) method has been developed for the numerical solution of the transient multigroup neutron diffusion and delayed precursor equations in two-and three-dimensional geometry.

TL;DR: In this paper, the verification of computer codes capability to simulate water hammer type transients is a very important issue at performing safety analyses for nuclear power plants employing the experimental investigations is presented and experience gained from benchmarking analyses is used at development of the detail RELAP5 code RBMK-1500 model for simulation of water hammer effects in reactor main circulation circuit.

TL;DR: In this article, a methodology is presented for the accurate assessment of the fast neutron fluence at the reactor pressure vessel (RPV) of a pressurised water reactor (PWR).

TL;DR: In this paper, the delayed supercritical process of a nuclear reactor with temperature feedback while inserting small step reactivity is analyzed, and the expression of relation between reactivity and time is derived.

TL;DR: The CNN model is used to simulate space-time response of different reactivity excursions in a typical nuclear reactor and the efficiency of the calculation method makes it useful for small size nuclear reactors such as the ones used in space missions.

TL;DR: In this article, a two-step analysis procedure was established for the prismatic VHTR physics analysis by combining all the methodologies described above, and the applicability of their code system was tested against core benchmark problems.

TL;DR: In this article, the authors investigated the use of a Monte Carlo method called sampling importance resampling (SIR) for the estimation of the nonlinear dynamics of a nuclear reactor, as described by a simplified model of literature.

TL;DR: In this article, a bridge is built between the reduced order model (ROM) and the system code RAMONA for the stability analysis of a specific operational point of the Leibstadt nuclear power plant.

TL;DR: In this article, a new methodology for absolute measurement of the effective delayed neutron fraction beff based on Feynman-a experiments and the two-region model was developed, which is able to obtain beff with the required accuracy and without knowledge of any other parameter.

TL;DR: The main contribution of this study is the development of an efficient procedure for BWR fuel lattice design, using GA with an objective function (OF) which saves computing time because it does not require lattice burnup calculations.

TL;DR: Suetomi et al. as mentioned in this paper presented a scheme to obtain the fundamental and few dominant solutions of the prompt time eigenvalue problem for a nuclear reactor using multi-group neutron diffusion theory.

TL;DR: In this article, a multi-dimensional flow boiling model is proposed to simulate the thermal-hydraulic characteristics and released nuclide distribution in the steam generator secondary side, which can provide the local velocity, temperature, enthalpy, void fraction, etc.

TL;DR: In this paper, a spectral nodal method was developed for the solution of one-speed discrete ordinates (S N ) problems with isotropic scattering in X, Y geometry, where the spectral Green's function (SGF) was generalized to solve the one-dimensional transverse-integrated S N linear-nodal equations with linear polynomial approximation for the transverse leakage terms.

TL;DR: From the results, it is able to conclude that the Metropolis sampling algorithm can be used for the simulations as it provides more accurate results and is also time efficient in comparison to the NTC and modified direct sampling algorithms.

TL;DR: The QuinalliBT system, a new approach to solve fuel loading and control rod patterns optimization problem in a coupled way, was tested and applied to a real BWR operation cycle and it was found that the value for keff obtained was 0.0024 Δk/k greater than that of the reference cycle.

TL;DR: A comparison of the spatially adaptive grid-refinement approach with that of uniform meshing approach for various benchmark cases confirms its superiority in greatly enhancing the accuracy of the solution without increasing the number of unknown coefficients.