[en] The publication contains 11 contributions, of which 8 have been input to INIS. (P.A.)

[en] Systems to detect any ionising radiation source in scrap are routinely installed at the input to metallurgical plants. Tracking by means of hand instruments enables removing various radioactive materials from scrap. Materials can be contaminated by natural radionuclides (e.g. materials of the NORM type) and by artificial radionuclides (e.g. ⁶⁰Co in steel products). If radioactivity is detected, the material is disposed of in compliance with applicable legislation

[en] The 70th anniversary of the discovery of spontaneous fission by the young Russian physicists Konstantin A. Petrzhak and Georgii N. Flerov is commemorated. The situation in the 1940s is described and the activities of the 2 scientists, including their involvement in the development of the A-bomb, is outlined. (P.A.)

[en] Owing to a number of assets, which are outlined, neutron activation analysis (NAA) finds application in chemical metrology, specifically in the preparation of reference materials (RMs) of chemical composition and in analytical quality control. The self-verification principle is a special feature of NAA serving to verify analytical data produced by this technique. The strategies of the self-verification principle are explained and examples of its utilization are presented. Recently, NAA has been recognized as a primary method of measurement

[en] The article is structured as follows: Fuel pin leak tightness evaluation: In-service inspections; Inspections during outages; Off-line sipping test; Repair of damaged fuel assemblies by mean of MSIO. (P.A.)

[en] The methods of determination of ¹⁴C are outlined, and a comparison between the conventional methods and the processing of microsamples with measurement by accelerator mass spectrometry is presented. The assets of the processing of microsamples are highlighted and some applications are described. The development potential of the conventional method which is based on the synthesis of benzene and measurement by LSC at our laboratory is discussed. Currently, our radiocarbon laboratory performs experiments aimed at the processing of microsamples and preparation of graphitized targets. As to the control of the analytical methods, radiocarbon dating using existing dated material for repeated analyses and comparison of dating results with those obtained by other laboratories is a convenient approach

[en] This paper deals with laboratory determination of adsorption isotherms parameters. Granite from the central moldanubian pluton, site Panske Dubenky. Czech Republic, was chosen for the experiment. The place is one of the candidate sites to build a deep nuclear waste disposal facility. A batch experiment was performed in two modes, differing in the way of addition of radioactive nuclide ⁹⁰Sr. From this experiment- distribution coefficients for a linear isotherm or parameters for Langmuir isotherm were obtained. In addition, a through-diffusion experiment was performed. The objective of this experiment was to find whether some of the radionuclides ¹³⁷Cs, ⁹⁰Sr, ¹²⁵I is able to penetrate through the pores of a granite slice barrier between two solutions of different concentrations. During the period of the experiment no radionuclide was detected reliably. (author)

[en] The feasibility of nondestructive determination of fluorine in coal and other geological materials by instrumental photon activation analysis (IPAA) was studied. The method uses the non-specific 511 keV annihilation gamma rays of ¹⁸F, product of the ¹⁹F(γ, n)¹⁸F photonuclear reaction which is a pure positron emitter. The simultaneous formation of some other positron emitters, particularly ⁴⁵Ti and ^34mCl, interferes. Interferences from ²²Na, ⁴⁴Sc, ⁸⁹Zr, ⁷⁴As, and ⁸⁴Rb are small or negligible. Owing to an optimization of the beam energy and irradiation-decay-counting times and to the use of correction standards for the interfering nuclides, IPAA enables fluorine in selected USGS geochemical reference materials and NIST coal standards to be determined at levels as low as 10 ppm. The optimized procedure was applied to assaying fluorine in selected coals mined in the Czech Republic

[en] Two methods for determination of the most important parameters: retardation and hydrodynamic dispersion coefficients of ¹²⁵I^-, ¹³⁷Cs⁺ and ⁸⁵Sr²⁺ in crushed diorite and tonalite rocks, as well as in a homogenized soil of loamy sand type have been described. The sorption behavior of these radionuclides, injected into the stream of synthetic groundwater in a single pulse, was investigated in a dynamic flow column arrangement, which experimental details were given previously. Both methods apply breakthrough curves derived from the integral form of 1-D advection-dispersion equation using correction coefficients on the peak position and peak height. The first method uses a linear isotherm approach, when the radionuclide distribution coefficient (K_d) is supposed constant (linear sorption model) the other model applies a non-linear isotherm approach, when K_d is changing during the transport (Freundlich sorption model). In both models a method of non-linear regression has been used. From the comparison of these different models it followed that the non-linear approach gives more accurate and reliable results. (author)