No abstract available

[en] The 10 kW JASON Argonaut research and training reactor was commissioned over thirty years ago and it has recently been subjected to a detailed safety assessment based on present day technologies and methodologies. As part of this assessment a Long Term Safety Review (LTSR) has been carried out in accordance with guidelines used in the LTSR of the UK's MAGNOX power plants. However, the operational history of low power research reactors and the limited potential for harm to the public and workers are important factors in reducing the scope of the LTSR when compared with that required for power reactors. In addition, periodic review of the safety case and team audits provide substantial support for the LTSR. This study will review the methodologies employed in producing an LTSR for JASON that has been endorsed by the appropriate safety regulators. (orig.)

[en] Full text: This paper reports an R and D which has the purpose of performing dose assessment of workers in nuclear plants, through virtual simulations using a game engine. The main objective of this R and D is to support the planning of operational and maintenance routines in nuclear plants, aiming to reduce the dose received by workers. Game engine is the core of a computer game, that is usually made independent of both the scenarios and the original applications, and thus can be adapted for any other purposes, including scientific or technological ones. Computer games have experienced a great development in the last years, regarding computer graphics, 3D image rendering and the representation of the physics needed for the virtual simulations, such as gravity effect and collision among virtual components within the games. Thus, researchers do not need to develop an entire platform for virtual simulations, what would be a hard work itself, but they can rather take advantage of such well developed platforms, adapting them for their own applications. The game engine used in this R and D is part of a computer game widely used, Unreal, that has its source code partially open, and can be pursued for low cost. A nuclear plant in our Institution, Argonauta research reactor, has been virtually modeled in 3D, and trainees can navigate virtually through it, with realistic walking velocity, and experiencing collision. The modified game engine computes and displays in real-time the dose received by a virtual person, the avatar, as it walks through the plant, from the radiation dose rate distribution assigned to the virtual environment. In the beginning of this R and D, radiation dose rate measurements were previously collected by the radiological protection service, and input off-line to the game engine. Currently, on-line measurements can be also input to it, by taking advantage of the game's networking capabilities. A real radiation monitor has been used to collect real-time radiation dose rate measurement and input this data to the game engine through a TCP/IP network. Another advantage of this approach is that radiation dose rate distribution can be mapped by any available method, from measurements or computation. We are planning to expand this application to consider a number of networked radiation dose monitors installed in the real plant, to map the dose rate and to perform the simulations in real-time. Any other nuclear plant can be simulated, depending on the availability of measured data, or radiation monitors installed in the real plant. (author)

No abstract available

[en] The dismantling of a nuclear facility is at the same time a technical and an economic challenge. One of the main economical aspects concerns the optimisation of nuclear waste. From this point of view, this work describes the dismantling of the research reactor at the University of Strasbourg. Built in 1966, this reactor went critical for the first time on 22 November 1966 and began to operate at nominal power in April 1967. After 31 years of service, the facility was shut down on 23 December 1997. The dismantling project began in the summer of 2006 and is scheduled for completion in the summer of 2008. In this paper we will share the experience gained with this project. (author)

[en] After a mention to the Argentine regulation of 1945 concerning the export of uranium ores and a short description of the 'Richter affair', the decree 10936 of 1950, that creates the Argentine Atomic Energy Commission (CNEA) , is analyzed. The activities of the CNEA between the years 1952 - 1955 are also outlined

[en] The dependence of rod vibration induced, neutron density fluctuations on the static neutron gradients was investigated experimentally at the QMC research reactor. By appropriate fuel loading arrangements the rod was made to vibrate within (a) flat flux and (b) a flux gradient. The neutron density was fluctuating with the frequency of the vibrating absorber only when the static flux gradient in the vicinity of the absorber was not zero. The double frequency effect was not observed. (author)

No abstract available

[en] Much of present day nuclear reactor mathematics is concerned with numerical methods which require the use of giant digital computers. Even as little as a quarter of a century ago sturdy rulers and ink pens were used as graphical aids to computation. These aids, or at least their computer analogues, still play a part in computation, although the present fashion is to use floppy rulers and light pens. (author)

[en] The work is devoted to evaluating the accuracy of using the system of constants together with the discrete ordinate method and the computer codes for studying the passage of neutrons and photons through water and steel gratings. The results of calculating the benchmark models for radiation protection database are presented in experimental channel of the NESTOR reactor. As a neutron source, a disk made of an alloy of uranium and aluminum irradiated with a stream of thermal neutrons leaving the NESTOR reactor was used