Radiochemical analysis of concrete samples from accelerator waste (original) (raw)
Related papers
Journal of Radioanalytical and Nuclear Chemistry, 2020
Cement is an important component of concrete used as a shielding material in nuclear accelerators and reactors. Hence cement samples should be analysed for the presence of certain trace elements that may get activated by neutrons emitted during the production of radioisotopes in an accelerator, so as to minimize the low level radioactive waste to be handled during decommissioning. With this motivation the present work was undertaken and 44 samples of five broad classes of cements were analysed for natural radioactivity (226 Ra, 232 Th & 40 K) and trace elements capable of generating long lived gamma radioactivity due to neutron activation.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2007
We use a description of the work carried out to determine the radioactive inventory for a redundant beam-dump from the PSI accelerator complex, as an illustration of techniques for the classification and characterisation of accelerator waste and how some difficulties can be circumvented. The work has been carried out using a combination of calculation and sample analysis: The inventory calculation effectively involves a large scale Monte-Carlo transport calculation of a medium-sized spallation facility and for the sample analysis, standard radiochemical analysis techniques have had to be extended to include AMS measurements so as to allow measurement of some of the long half-life, waste disposal relevant, nuclides.
Radioactive Contamination of Concrete: Uptake and Release of Radionuclides
Concrete in nuclear installations may become contaminated by various radionuclides. Consequently, decommissioning and dismantling produce considerable quantities of potentially contaminated materials that must be managed safely and cost-effectively. In this paper we present preliminary results from a research project that aims to improve knowledge about release behaviour of radionuclides from contaminated concrete, and that proposes a scientific approach to calculating the source term for radiological dose assessment for the various management options (e.g. direct reuse, recycling, disposal of rubble).
Radioactivation Analysis of Concrete Wall in OKTAVIAN Facility
Plasma and Fusion Research
A deuterium-tritium (DT) neutron generator in Osaka University with a continuous intense neutron source emitting 3 × 10 12 fusion neutrons per second has been in operation since 1981. However, radioactivation for the parts of the accelerator body is a serious issue. Hence, in this study, we investigated the radioactivation of the intense irradiation room containing the continuous intense neutron source. Core samples of the concrete wall were collected at various positions in the irradiation room and the radionuclides in them were determined by performing gamma-ray spectrometry. Major long-lived radionuclides found were 54 Mn, 60 Co, and 152 Eu. The radioactivity of 152 Eu may possibly be consistent with the result obtained using the simulation code. The radioactivities of 54 Mn and 60 Co were minimal compared with that of 152 Eu. The tritium amount in the core sample was measured employing a tritium sampling system and a liquid scintillation detector and was found to be considerably larger than the amount estimated using the simulation code. Tritium diffused from the titanium-tritium target was attached to the wall surface. However, most of it did not penetrate the concrete wall. These results reveal the radioactivity issue of fusion neutron generator facilities and are expected to aid in the maintenance of their operation.
Assessment of long-lived residual radioisotopes in cement induced by neutron radiation
MATEC web of conferences, 2020
During the decommissioning of nuclear power plants, a significant amount of cement based composites should be disposed as radioactive waste. The use of material with low-activation constituents could effectively reduce radioactivity of concrete. The subject of the paper is the content of trace elements with large activation cross section in concrete constituents due to their ability to be activated in radiation shielding structures. Various Portland cement specimens were subjected to elemental analysis by neutron activation analysis and prompt gamma activation analysis to assess the dominant long-lived residual radioisotopes. Concentrations of the radionuclides, such as Europium-152, Cobalt-60 and Caesium-134 were assessed. Their half-life time is 13.5, 5.27, and 2.07 years, respectively. On the basis of the obtained results, recommendations for cement selection for low-activation concrete are proposed in order to economize decommissioning cost by reducing a radioactive concrete waste.
Journal of Radioanalytical and Nuclear Chemistry
This paper reports the results obtained in a Nordic Nuclear Safety Research project during the second intercomparison exercise for the determination of difficult to measure radionuclides in decommissioning waste. Eight laboratories participated by carrying out radiochemical analysis of 3H, 14C, 36Cl, 41Ca, 55Fe and 63Ni in an activated concrete. In addition, gamma emitters, namely 152Eu and 60Co, were analysed. The assigned values were derived from the submitted results according to ISO 13,528 standard and the performance assessments were determined using z scores. The measured results were compared with activation calculation result showing varying degree of comparability.
Elemental analysis of a concrete sample by capture gamma rays with a radioisotope neutron source
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1995
Gamma radiation from capture of neutrons in concrete has been studied in the energy region from 0.3 to 10.5 MeV with a HPGe spectrometer and an AmBe neutron source. A careful analysis of the Fe, Si, Ca, and Cl peak intensities made it possible to determine their relative concentrations in the sample. A comparison has been made between this nuclear method and chemical techniques, resulting in good agreement. The employment of these nuclear reactions constitutes a promising technique for the bulk analysis of samples in the concrete industry, because of its nondestructive and in-situ nature.
Annals of nuclear medicine, 2015
Compact medical cyclotrons have been set up to generate the nuclides necessary for positron emission tomography. In accelerator facilities, neutrons activate the concrete used to construct the vault room; this activation increases with the use of an accelerator. The activation causes a substantial radioactive waste management problem when facilities are decommissioned. In the present study, several concrete cores from the walls, ceiling and floor of a compact medical cyclotron vault room were samples 2 years after the termination of operations, and the radioactivity concentrations of radionuclides were estimated. Cylindrical concrete cores 5 cm in diameter and 10 cm in length were bored from the concrete wall, ceiling and floor. Core boring was performed at 18 points. The gamma-ray spectrum of each sample was measured using a high-purity germanium detector. The degree of activation of the concrete in the cyclotron vault room was analyzed, and the range and tendency toward activation...
Radiation effects on the properties of concrete used in nuclear power plants
EMERG - Energy. Environment. Efficiency. Resources. Globalization
Inside the concrete used as a material for the protection shields against ionizing radiation coming from the core of the reactor, various processes and physical and chemical reactions have to be taken into account when the efficiency of the shield is analyzed throughout the operation life of the nuclear power plant. The paper looked at how the concrete can be affected by the irradiation with neutrons and gamma radiation under conditions of possible high fluence outside an reactor core.
Radiochemical analysis of a copper beam dump irradiated with high-energetic protons
Radiochimica Acta, 2009
The radionuclide inventory of a copper beam dump from the 590 MeV proton accelerator of the Paul Scherrer Institute in Switzerland was determined, focusing on radioisotopes with half-lives of more than 60 d, and in particular, of long-lived isotopes with T 1/2 = 10 4-10 7 years, which are important regarding radioactive waste management. The measurements were carried out using high resolution γ-measurement without sample destruction, as well as liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS) after chemical separation. For the first time, a beam dump from a high power accelerator facility was completely characterized concerning the depth and radial distribution profile of the most hazardous and/or long-lived radionuclides. Moreover, it turned out that some of the investigated radionuclides, like for instance 26 Al, 44 Ti or 60 Fe represent valuable material for application in several scientific fields like nuclear astrophysics, basic nuclear physics research, radiopharmacy and many others. Therefore, based on the analytical results, a special research and development program has been started at PSI objecting on specific preparative extraction of longlived radioisotopes (ERAWAST-exotic radionuclides from accelerator waste for science and technology).