Search results for "Radioactive Waste"

Nuclear Radii and Moments of Unstable Isotopes

1989

The development of on-line mass separators, which provide long chains of isotopes extending far off stability, immediately raised the question of how to gain access to the basic nuclear ground-state properties of these exotic nuclei—their spins, moments, radii, and masses. In general, the amount of radioactive material produced at these facilities is too small to form beams or targets for any kind of scattering or nuclear-reaction experiment. On the other hand, the traditional spectroscopic methods, namely, atomic, nuclear, and mass spectroscopy, have turned out to be very suitable for this application since they are easily adapted to the special on-line conditions.

Nuclear data activities at the n_TOF facility at CERN

2016

International audience; Nuclear data in general, and neutron-induced reaction cross sections in particular, are important for a wide variety of research fields. They play a key role in the safety and criticality assessment of nuclear technology, not only for existing power reactors but also for radiation dosimetry, medical applications, the transmutation of nuclear waste, accelerator-driven systems, fuel cycle investigations and future reactor systems as in Generation IV. Applications of nuclear data are also related to research fields as the study of nuclear level densities and stellar nucleosynthesis. Simulations and calculations of nuclear technology applications largely rely on evaluate…

Hydro-Mechanical Behaviour of a Sand-Bentonite Mixture for the Confinement of Nuclear Wastes

2019

The established concept for the protection of the biosphere from high-level nuclear wastes consists in the use of multi-barrier systems in deep geological repository, for which clayey geomaterials are key elements. Bentonite-based materials are selected as buffer and backfilling materials. Once in place, the barriers will be subjected to a series of severe loadings, including strong variations of suction (i.e. wetting and drying cycles). The paper presents selected results from a large ongoing research work to investigate the behaviour of bentonite-based materials in the context of nuclear waste disposal. In particular, the paper focuses on the response of a Sand/Bentonite mixture under dif…

Determination of the Porosity, Permeability and Diffusivity of Rock in the Excavation-Disturbed Zone Around Full-Scale Deposition Holes Using the He-…

1999

AbstractIn a nuclear waste repository, rock in the excavation-disturbed zone adjacent to the walls of deposition holes for waste canisters is a potential pathway for the transport of corrosive agents and radionuclides. Three experimental holes the size of deposition holes in a KBS-3 type repository (depth 7.5 m and diameter 1.5 m) were bored in hard granitic rock in the Research Tunnel at Olkiluoto and the porosities, effective diffusivities and permeabilities of rock in the excavation-disturbed zone were determined in a direction parallel to the disturbed surface using He-gas methods. Permeability and diffusivity in a direction parallel to the rock schistosity was found to be clearly large…

On the use of stacks of fission-like targets for neutron capture experiments

2019

The measurement of neutron induced reactions on unstable isotopes is of interest in many fields, from nuclear energy to astrophysics or applications; in particular transuranic isotopes are essential for the development of innovative nuclear reactors and for the management of the radioactive waste. In such measurements, the quality of the associated radioactive target is crucial for the success of the experiment, but in many cases the geometry, amount of mass and encapsulation of the target are not optimal, leading to limited results. In this work we propose to produce high quality radioactive targets for capture as a stack of thin targets using the techniques usually employed for fission me…

The critical Swedes and the consensual Finns: Leading newspapers as watchdogs or lapdogs of nuclear waste repository licensing?

2020

Abstract The final disposal of spent nuclear fuel has long stirred up societal debate and controversy in most countries utilizing nuclear energy. Various discourses contextualising the issue affect both the general public and policy-making. Both Finland and Sweden are considered forerunners in implementing final disposal. In this paper we explore similarities and differences in media attention paid to final disposal in Finland and Sweden by focusing on two leading newspapers in each country during the time period of 2008–2015. A longitudinal comparative study suggests that there are clear national differences in the roles assumed by print media in the handling of the final disposal issue. I…

The rationality of acceptance in a nuclear community: analysing residents' opinions on the expansion of the SNF repository in the municipality of Eur…

2010

The project to build a final disposal repository for Spent Nuclear Fuel (SNF) in the municipality of Eurajoki, Finland, is approaching its 2012 deadline for the application of a construction licence. At the same time, the nuclear waste company Posiva is already planning to expand the disposal capacity of the repository. This paper addresses the question of acceptance among the residents of Eurajoki regarding the repository's expansion, and examines what aspects should be taken into consideration when explaining local opinions. The local acceptance figures for Eurajoki are analysed in relation to assumptions of the six common explanation types. The relationship between information deficit, s…

2018

A vigorous anti-nuclear movement emerged in Germany in the mid 1990s, when spent nuclear fuel elements began to be transported to the interim storage facility in Gorleben, Lower Saxony. Resistance ...

Neptunium(V) Sorption and Diffusion in Opalinus Clay

2009

The sorption and diffusion behavior of 8 x 10(-6) M Np(V) in Opalinus Clay (OPA) with synthetic pore water (pH 7.6) as mobile phase was studied under ambient conditions by batch and diffusion experiments, respectively. The Kd value determined by batch experiments with OPA suspensions is equal to 0.025 +/- 0.005 m3/kg. The diffusion-accessible porosity epsilon of intact OPA as determined by through- and out-diffusion experiments with tritiated water (HTO) is equal to 0.15 +/- 0.01. The diffusion coefficient De and the rock capacity factor alpha of 22Na+ in OPA were measured by through-, out-, and in-diffusion experiments and asserted the reliability of these diffusion techniques. For the dif…

Nuclear Power, No Thanks?

2012

The greatest misunderstanding related to nuclear energy, which is continuously exploited by its opponents, is the nature of radioactivity. Pierre and Marie Curie carried in the pockets of their laboratory coats test tubes full of highly radioactive substances, unaware that gamma radiation could be harmful at high doses. In contrast, antinuclear propaganda has been so effective that most people are convinced that any radioactive “leakage” is deadly or that radioactive waste has to be buried at a depth of kilometers to avoid harmful effects—in fact, a few meters of soil is enough to absorb even the most intense gamma radiation—or that cancer risk grows exponentially due to nuclear power plant…