Showing papers in "Annals of Nuclear Energy in 1980"

TL;DR: An approximation method for solving certain types of neutron transport problems makes use of asymptotic expansions in terms of a dimensionless parameter, which is assumed small and is usually defined as epsilon = typical mean free path/characteristic length of the physical system as mentioned in this paper.

TL;DR: Evaluation of dynamic system descriptors in PWRs using the multivariate analysis is presented for the first time in this paper and applications of mini computer oriented algorithms are evaluated using test data from operating power reactors.

TL;DR: In this article, the authors developed a method for monitoring control rod vibrations by neutron noise measurements, and the noise induced by two-dimensional vibrations of control elements was investigated, and two possible diagnostical applications were considered: (a) the reconstruction of the mechanical trajectory of the vibrating element, and (b) the possibility of locating the vibration element in the core.

TL;DR: In this paper, a mathematical model of thermally induced water movement in the vicinity of a hard rock depository for radioactive waste is presented and discussed, where the equations describing heat and mass transfer become uncoupled and linear.

TL;DR: In this article, the (n, 2 n ) isomeric cross section ratio and the ( n, 2 n) and ( n, α) excitation functions for 59 Co have been measured in the energy range 13.4-18.1 MeV by activation techniques using the mixed-powder method and Ge(Li) detector γ-ray spectroscopy.

TL;DR: In this paper, Radiative transfer in plane-parallel inhomogeneous atmospheres is discussed from the points of view of the integral and the integro-differential forms of the equation of transfer.

TL;DR: In this paper, it is shown that the fluctuations of the neutron population can be uniquely separated into a local and a global component with each component satisfying a second-order differential equation, and that under certain limitations, the two-group treatment of the neutrons and the subsequent derivation of the two components, is equivalent to the one-group theory in which the slowing down of the fast neutrons is taken into account through an appropriately chosen slowing down kernel.

TL;DR: In this paper, the one group finite element formulation of the neutron transport equation is adapted to treat multigroup shielding problems, and the method is extended to eigenvalue problems by using a source iteration technique.

TL;DR: In this paper, the authors present a comprehensive review of common-mode/common-cause (CM/CC) failure and its prevention in the nuclear safety community during the past few years.

TL;DR: In this paper, the criticality factor of infinite slabs with monoenergetic neutrons scattering anisotropicically was determined by using the discrete ordinates method, up to the S32 approximation for the thinnest slab.

TL;DR: In this article, a nonlinear system formed by the original kinetics equations and a normalization condition 〈 o, ψ 〉 = 1 was used to define various quasistatic algorithms, i.e., solutions factorized into an amplitude function T and a shape function ψ.

TL;DR: In this article, the 239 Pu fission cross-section measurements were performed covering the neutron energy region from thermal up to 30 keV and different methods were applied for the neutron flux determination.

TL;DR: In this article, the authors measured cross sections for two high energy threshold reactions 23 Na(n, 2 n ) 22 Na and 58 Ni(n, 2 n ), 57 Ni were measured by the activation method in the neutron energy range from 14 to 18 MeV.

TL;DR: The non-linear partial differential integral Benjamin-Ono equation is shown to have almost all the properties of completely integrable nonlinear PDE equations epitomized by the Korteweg-de Vries equations.

TL;DR: In this article, a simplified mathematical model for which analytic solutions to the temperature and stress fields are derived are derived. But this model assumes that the waste is stored in a hard rock and does not consider the possibility of water-borne leakage of radionuclides.

TL;DR: In this article, the Langevin equation with the system-size expansion has been used to study the power fluctuation in a nuclear reactor at power taking into account the nonlinearities of the point reactor kinetic equation.

TL;DR: Although transport theory is one area of modern day research which Albert Einstein did not create, I have decided to speak on Einstein at this transport theory conference as mentioned in this paper, partly to honor this great scientist on the occasion of the centenary of his birth (14 March 1979).

TL;DR: In this article, a code called superb has been developed for the BWR fuel assembly burnup analyses using a supercell model, which is achieved by building isotopic densities in each fuel pin separately while the depletion equations are solved only in a few group of pins or burnup zones and the multigroup neutron spectra are differentiated in fewer group of pincell types.

TL;DR: In this paper, the authors apply the Novikov-Furutsu formula to neutron kinetics and statics in a multiplying medium with a statistically fluctuating reactivity, and find that the noise introduces a new definite production term into the conventional balance equation for the mean neutron number.

TL;DR: In this paper, tracklength biassing is employed in Monte Carlo Radiation Transport to obtain, within reasonable computer time, statistically reliable estimates of neutron and gamma transmission through thick shields, where the material cross section of the shield medium is multiplied by a factor " a " so that the particle tracks toward the shield exit are stretched.

TL;DR: In this paper, two approaches (two-group diffusion theory and one-group theory with slowing down kernel) which provide the theoretical justification of the separation of the neutron noise in water moderated reactors into a local and a global component are reviewed, and it is shown that the solutions obtained by either method are equivalent.

TL;DR: In this article, the F N method is used to solve the critical problem for a slab reactor with a finite reflector, and numerical results for the critical thickness are shown for different values of the mean number of secondary neutrons per collision and reflector thickness.

TL;DR: In this article, the F N method was used to solve the critical problem for a three-region reactor and to compute the disadvantage factor required for thermal utilization calculations, and numerical results were given.

TL;DR: In this paper, the authors apply the Box and Jenkins auto-regressive moving-average ARMA models to the analysis of several temperature time-series measured by the Commissariat a l'Energie Atomique in the course of the CFNa experiment carried out at the nuclear center of Grenoble.

TL;DR: In this paper, the thermal neutron induced fission cross-section of 232Th was measured at an intense and very pure thermal neutron beam of the Grenoble High Flux Reactor, yielding a value of (3 ± 1) μbarn.

TL;DR: In this paper, a parallel derivation of the forward Kolmogorov equation (FKE) and of the backward KG equation (BKE) from detailed probability balance equations for a population of neutrons, precursors and detected neutrons living in a multiplying medium where processes of capture and leakage, fission, precursor decay, detection and source emission occur.