Search results for "Nuclear reactor"

The n_TOF facility: Neutron beams for challenging future measurements at CERN

2016

The CERN n TOF neutron beam facility is characterized by a very high instantaneous neutron flux, excellent TOF resolution at the 185 m long flight path (EAR-1), low intrinsic background and coverage of a wide range of neutron energies, from thermal to a few GeV. These characteristics provide a unique possibility to perform high-accuracy measurements of neutron-induced reaction cross-sections and angular distributions of interest for fundamental and applied Nuclear Physics. Since 2001, the n TOF Collaboration has collected a wealth of high quality nuclear data relevant for nuclear astrophysics, nuclear reactor technology, nuclear medicine, etc. The overall efficiency of the experimental prog…

Determination of elemental levels in medicinally important Indian leaves by instrumental neutron activation analysis

1998

Levels of As, Ba, Br, Ca, Ce, Cl, Cr, Cs, Eu, Fe, Hg, I, K, La, Mg, Mn, Na, Ni, Rb, Sb, Sc, Sm, Sr, Th, Zn, and U have been determined in ten leaves widely used in ayurvedic medicine by instrumental neutron activation analysis (INAA). The neutron irradiations were performed with a 100 kW Triga nuclear reactor and the induced activity was counted with a gamma-ray spectrometer. Based on elemental levels obtained the utility of these leaves in medicine are discussed.

Shakedown Analysis by Elastic Simulation

2000

Shakedown analysis of elastic plastic structures is widely credited as a valuable analytical/numerical tool for design purposes. For complex structures and loading conditions, e. g. for fast breeder nuclear reactor plants, full inelastic analysis is rarely performed, practically never within the early stages of the design advancement and the inherent decision process. The essential information therein needed can in fact be obtained, at moderate computational costs, by application of the shakedown methods and rules, at least within some limits related to the present developments of shakedown theory and its applicability to practical engineering problems, see e. g. Ponter et al. (1990), Carte…

Determination of gunshot residues by neutron activation analysis

1973

Systematic investigations of gunshot residues, deposited around the bullet hole, have been carried out. The traces were produced by firing on filter papers from distances of 5 to 200 cm using one rifle and three pistols as arms. Antimony, lead and barium were quantitatively determined after irradiating the samples in the nuclear reactor TRIGA Mainz by measurement of gamma-lines of122mSb,122Sb,207mPo and139Ba. The determinations were made purely instrumentally and-where the half lives were long enough-also after chemical separation of the nuclides. The amount of the elements were determined in dependence of the firing distance and of the area around the bullet hole.

Natural Convection Cooling of a Hot Vertical Wall Wet by a Falling Liquid Film

2008

Abstract The system studied is a plane channel in which one of the two vertical walls is kept at an arbitrary temperature profile and may be partially or completely wet by a falling liquid film, while the opposite wall is adiabatic. Air from the environment flows along the channel with a mass flow rate which depends on the balance between hydraulic resistances and buoyancy forces. These latter, in their turn, depend on the distribution of temperature and humidity (hence, density) along the channel and eventually on the heat and mass transferred from wall and film to the humid air. A simplified computational model of the above system was developed and applied to the prediction of relevant qu…

The 15-Country Collaborative Study of Cancer Risk Among Radiation Workers in the Nuclear Industry: design, epidemiological methods and descriptive re…

2007

International audience; Radiation protection standards are based mainly on risk estimates from studies of atomic bomb survivors in Japan. The validity of extrapolations from the relatively high-dose acute exposures in this population to the low-dose, protracted or fractionated environmental and occupational exposures of primary public health concern has long been the subject of controversy. A collaborative retrospective cohort study was conducted to provide direct estimates of cancer risk after low-dose protracted exposures. The study included nearly 600,000 workers employed in 154 facilities in 15 countries. This paper describes the design, methods and results of descriptive analyses of th…

Analysis of a Station Black-Out transient in SMR by using the TRACE and RELAP5 code

2014

The present paper deals with the investigation of the evolution and consequences of a Station Black-Out (SBO) initiating event transient in the SPES3 facility [1]. This facility is an integral simulator of a small modular reactor being built at the SIET laboratories, in the framework of the R&D program on nuclear fission funded by the Italian Ministry of Economic Development and led by ENEA. The SBO transient will be simulated by using the RELAP5 and TRACE nodalizations of the SPES3 facility. Moreover, the analysis will contribute to study the differences on the code predictions considering the different modelling approach with one and/or three-dimensional components and to compare the capa…

Kodolspektroskopijas un beta radiometrijas rezultāti vides monitoringā Salaspils kodolreaktora apkārtnē (1966.g. līdz 1995.g.)

1998

The 15-Country Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry: Estimates of Radiation-Related Cancer Risks

2007

International audience; A 15-Country collaborative cohort study was conducted to provide direct estimates of cancer risk following protracted low doses of ionizing radiation. Analyses included 407,391 nuclear industry workers monitored individually for external radiation and 5.2 million person-years of follow-up. A significant association was seen between radiation dose and all-cause mortality [excess relative risk (ERR) 0.42 per Sv, 90% CI 0.07, 0.79; 18,993 deaths]. This was mainly attributable to a dose-related increase in all cancer mortality (ERR/Sv 0.97, 90% CI 0.28, 1.77; 5233 deaths). Among 31 specific types of malignancies studied, a significant association was found for lung cance…

An on-line mass separator for fission-produced alkali isotopes

1980

Abstract The design of an on-line mass separator installed at the TRIGA reactor in Mainz is described and its performance discussed. A tungsten oven, filled with about 2 g of 235U embedded in graphite, is exposed to a flux of 1.7 × 1011 thermal neutrons (s− cm−2) near the reactor core. After diffusion out of the graphite the fission-produced alkali isotopes are surface-ionized and electromagnetically mass-separated, the resolving power being about 750. Losses during the diffusion out of the target material are discussed. Due to these losses the maximum separator efficiency is about 5%, corresponding to a source strength of about 109 particles s−1 for the most abundant isotopes. The heaviest…