Identification of gas pipelines hydraulic efficiency coefficients

This study investigates the identification of non-measureable parameters of the gas transmission system (gas pipelines hydraulic efficiency coefficients). The problem statement and solution procedure are presented. The original problem is divided into two interrelated components: the nonlinear optimization problem and the temperature calculation. The nonlinear optimization problem is solved using the Successive Linear Programming (SLP) method. The problems of insufficiency of measurements and multiplicity of solutions are described, and appropriate approaches are proposed (introduction of additional subcriteria and uniting gas pipelines into groups). Identification of gas pipelines hydraulic efficiency coefficients for gas transmission systems of various complexity has been performed using the given algorithm

A method for nondestructive assay of nuclear materials in facilities with a pulse neutron generator and a digital technology for discrimination between neutrons and photons

A method for determining the U-235 concentration in fuel assemblies of a high-power channel-type PBMK reactor is described. The measure of U-235 content of an analyzed sample is the number of neutrons from thermal-neutron fission of U-235, normalized to the number of gamma quanta produced in thermal neutron capture by hydrogen nuclei in the scintillator or by B-10 in the glass of a photomultiplier tube. A pulse neutron generator based on DT reaction is the neutron source, and an organic scintillator with the pulse shape discrimination between neutrons and gamma rays with the aid of the digital technology is a detector. The scintillator is also used as a neutron moderator. Simulation of the method shows that the U-235 content of the analyzed sample can be determined for 1 min with an accuracy of 1% or better. The efficiency of the method has been confirmed by experimental investigations on a model of the setup

Experimental and numerical investigations of radiation characteristics of Russian portable/compact pulsed neutron generators: ING-031 ING-07, ING-06 and ING-10-20-120

The present paper discusses results of full-scale experimental and numerical investigations of influence of construction materials of portable pulsed neutron generators ING-031, ING-07, ING-06 and ING-10-20-120 (VNIIA, Russia) to their radiation characteristics formed during and after an operation (shutdown period). In particular, it is shown that an original monoenergetic isotropic angular distribution of neutrons emitted by TiT target changes into the significantly anisotropic angular distribution with a broad energy spectrum stretching to the thermal region. Along with the low energetic neutron part, a significant amount of photons appears during the operation of generators. In the pulse mode of operation of neutron generator, a presence of the construction materials leads to the "tailing" of the original neutron pulse and the appearance of an accompanying photon pulse at similar to 3 ns after the instant neutron pulse. In addition to that, reactions of neutron capture and inelastic scattering lead to the creation of radioactive nuclides, such as Co-58, Cu-62, Cu-64 and F-18, which form the so-called activation radiation. Thus, the selection of a portable neutron generator for a particular type of application has to be clone considering radiation characteristics of the generator itself. This paper will be of interest to users of neutron generators, providing them with valuable information about limitations of a specific generator and with recommendations for improving the design and performance of the generator as a whole. (c) 2014 Elsevier B.V. All rights reserved