Dans une centrale nucléaire (CNPE), la localisation despoints chauds est une préoccupation importante, car ils participentà la dose que reçoivent les intervenants, en particulier lors desopérations de maintenance. Depuis 2010, EDF et le CEA ont entreprisd’adapter une nouvelle génération de caméra gamma, GAMPIX, pourdisposer d’un instrument portable dédié à cet usage. Ce systèmepermet de superposer une image gamma à une image visible, afin delocaliser les sources radioactives présentes dans un environnement.Des essais sur site au CNPE de Tricastin ont été associés aux développements spécifiquesréalisés par le CEA, afin d’appréhender les conditions particulièresrencontrées en CNPE, à la fois environnementales et radiologiques :l’énergie relativement élevée des gamma du cobalt 60 (1,17 et 1,33MeV) et la présence d’un bruit de fond ambiant permanent. Cet article présenteles principaux axes du cahier des charges initial, les développementsréalisés pour y répondre, et les résultats obtenus lors des campagnesd’essais. Même s’ils étaient uniquement dédiés à la qualificationde la caméra gamma, les tests réalisés ont montré des résultatstrès prometteurs, par exemple la mise en évidence de lignes de fuitele long d’une protection biologique ou le mouvement d’un point chauddans une tuyauterie (par rapport à sa position identifiée). En dernier lieu,les développements futurs sont évoqués.

During and after the Fukushima accident, the IRSN collected and interpreted the resultsof radiological measurements performed on foodstuffs of terrestrial origin published byJapan's Ministry of Health between mid-March 2011 and July 2012. Analysis of the findingsshows that the accident's date, livestock-rearing practices and the deposits'characteristics had a decisive influence. The fact that radioactive fallout occurred veryearly in the growing and breeding season largely explains the moderate contamination ofmost foodstuffs of terrestrial origin, notably in the areas with the largest deposits. Inthe case of dairy products and meat, feeding imported fodder to livestock in stables, acommon practice in Japan, compounded the calendar effect. Measurements published in Japanhave also borne out the particular sensitivity of mushrooms, including cultivated species,and game.

The gamma-ray exposure build-up factors of raw materialsof bricks (soils and fly-ashes) in the state of Punjab were investigatedfor the photon energy range 0.015 to 15 MeV up to 40 mfp penetrationdepth by the geometrical progression (GP) method. Appreciable variationsin the exposure build-up factor (EBF) are noted for the raw materials.The EBFs of the raw materials of bricks change depending on thephoton energy, penetration depth and chemical composition. The build-up factorsare low at low and high photon energies, whereas they are very highin the medium-energy region. The peak energy of the EBF for soilsis 0.3 MeV and 0.2 MeV for fly ashes. The EBFs of the raw materialsof bricks are also compared with those of bricks of red mud andcommon brick materials. Common bricks were found to have the lowestgamma-ray EBF. This study should be useful for emergency preparednessplanning and emergency dose estimation for future planned nuclearpower plants in the state of Punjab.

In this paper, the effect of additional adipose and muscle layers was investigated on theeffective dose and the organ absorbed dose. Calculations were performed using the MonteCarlo N-Particle Transport Code (MCNP) and the ORNL mathematical phantom for externalphoton and neutron beams. Variations in adipose and muscle tissue thickness were modeledby adding layers of adipose and soft tissues around the torso of the phantom. Theeffective dose decreased by about 7%–40% when the thickness of the extra layer increasedfrom 0.5 to 5 cm considering all photon energies (10 keV–10 MeV) and neutron energies(10–9–20 MeV) for anterior-posterior, posterior-anterior, left-lateral,right-lateral, rotation and isotropic irradiation geometries. The results calculated herewere compared with those reported in previous studies such as those of the VIPMAN,NORMAN05, MASH-3 and ICRP reference voxel phantoms. Our data shows that adding properadipose or muscle layers to two very different phantoms can cause similar effective dosevalues, and also more than half of the organ absorbed doses have satisfactoryagreement.

Dans le but d’obtenir le déclassement de l’installation nucléaire de base 106 (INB 106),trois de ses accélérateurs ont été arrêtés puis démantelés et un autre modifié pour passersous le seuil de classement INB. Le démantèlement a été mené sur la base d’une stratégiede démontage mécanique sans découpe. Les éléments de génie civil peu activés ont pour latrès grande majorité été laissés en place sans traitement avec des mesures compensatoiresde protection du public et de l’environnement. Le résultat global de ces opérations est ungain en termes de coût et de délais et une importante diminution des risques notammentradiologiques, l’impact du site à l’état final restant acceptable.

Beach Sand Mining (BSM) is a profitable industry earning a sizable income for the countryby way of foreign exchange. The Indian coast is rich in rare earths such as ilmenite,rutile, leucoxene, zircon, garnet and sillimanite, and is invariably associated withradioactive monazite. Due to the nature of the separation processes involved and themanual handling, workers in these factories are continuously being exposed to suspendedparticles containing naturally occurring radioactive materials. An attempt was made toestimate DNA damage using a chromosome aberration assay to monitor radiation effects inworkers of BSM industries in India. The study group comprised 27 BSM workers and 20controls. Percentage yields of dicentrics, acentric fragments and chromatid breaksobserved in the control group were 0.058 ± 0.017, 0.073 ± 0.03 and 0.22 ± 0.112,respectively. Percentage yields of dicentrics + centric rings, acentric fragments andchromatid breaks observed in the BSM group were 0.029 ± 0.01 (P value 0.19), 0.24 ± 0.06(P value 0.006) and 0.455 ± 0.06 (P value 0.0004), respectively. Elevated levels offragments and chromatid aberrations are suggestive of low-dose radiation effects and alsochemically-induced DNA damage.

The activity concentrations of soil, water and fertilizersamples were determined by using high-resolution gamma spectrometry(HPGe detector: 40% relative efficiency) with a PC-based MCA system.The samples were collected from the area of a urea fertilizer factory,lagoon and Shitalakhya river in Narsingdi, Bangladesh. The activityconcentrations of 226Ra ranged from 3.16 ± 0.32 to 10.28 ± 0.55Bq.kg-1, 1.22 ± 0.41 to 7.36 ± 0.42 Bq.L-1 and 3.55 ± 0.33 to 90.65± 3.17 Bq.kg-1 for soil, water and fertilizer samples, respectively.The 232Th activity concentrations ranged from 4.89 ± 0.45 to 15.82± 0.45 Bq.kg-1, 1.21 ± 0.06 to 8.59 ± 0.37 Bq. L-1 and 4.76 ± 0.25to 26.38 ± 1.40 Bq.kg-1 for soil, water and fertilizer samples, respectively.The 40K activity concentrations ranged from 24.96 ± 0.23 to 60.49± 0.56 Bq.kg-1, 7.48 ± 0.53 to 35.48 ± 0.24 Bq.L-1 and 3.55 ± 0.05to 3051.71 ± 19.53 Bq.kg-1 for these samples, respectively. Theradium equivalent activity, the hazard indices, the gamma activityconcentration index, the indoor absorbed dose rate and the correspondingannual effective dose were estimated for the potential radiological hazardof the collected samples. The calculated values of the representativelevel index values (Igr) for all samples of the study area are lowerthan unity except the MOP sample. The activity ratios were alsomeasured. These values are compared with reported values for othercountries of the world. The results of the comparison studies showthat the radioactivity concentrations and other radioactive indicesof the samples of the study area are below the internationally acceptedmaximum permissible values. Therefore, this region is safe fromany radiation hazard and no significant radiological threat was observedto the population of the study area.