385 research outputs found
Cs-137 contamination in wild boars in Sesia Valley, Italy
Traces of cesium-137, well above the threshold set out in the Italian regulations, have been found in wild boars in the alpine area of the Sesia Valley, Piedmont, Italy.
We analyzed samples of tongue and diaphragm of animals slaughtered during the hunting season 2012-2013 and in 27 of these the level of cesium was higher than the threshold specified by the Italian Regulation 733 of 2008, dealing with the tolerable limit in the event of a nuclear accident. In fact, 27 samples have values above 600 Bq/kg, reaching up to 5600 Bq / kg in one sample, i.e., about ten times the limit. Cesium-137 is a radioactive isotope released, in 1986 from the Chernobyl disaster. It would seem that the contamination of these boars is so high due to the Chernobyl fallout and not, as it was thought at first, due to a radioactive medical source abandoned and disposed of illegally.
According to ARPA Piemonte (Governmental Regional Agency), the fall-out from Chernobyl was particularly high in certain areas of Piedmont, including the Sesia Valley, and it is not uncommon to find wild boars so contaminated and, in particular, this has already happened in other areas heavily contaminated by Chernobyl fallout as the Sesia Valley was.
A radiological test has been carried out, to assess conclusively that cesium-137 in the boars is "old Cesium" from Chernobyl and nothing something coming from a new contamination. Cs-137 (which has a half-life of 30 years) came from Chernobyl mixed with the shortest-lived isotope Cs-134 (which has half-life of about 2 years). In particular, in May 1986, the ratio of the radioactivity of Cs-137 versus Cs-134 present in the cloud and deposited on Italian soil was equal to about two (1.94): in other words, the radioactivity from Cs- 134 was approximately half that from Cs-137.
But the radioactivity from Cs-134 is halved every two years, while the longest Cs-137 halves every 30 years. So now, 27 years after Chernobyl, the radioactive concentration from Cs-134 has halved more than 13 times, falling to very little, while that of Cs-137 is still a bit 'more than a half of the original one. So, if we analyze the Chernobyl Radioactive cesium today, the ratio of the radioactivity of Cs-137 and Cs-134 is no longer near 2, but it has become, in favor of Cs-137, about 8900.
A further analysis has been performed with more precise measurements: the radioactive contamination of our boars shows a radioactivity of Cs-134 in their flesh almost imperceptible, but in the order - in the maximum case of the 5600 Bq/kg contamination – of 0.6 Bq/kg. Then it is confirmed that it is due to the heritage of the Chernobyl cloud contamination.
However, the wild boars are “sentinel animals” for pollution conditions in the areas where they live, because they provide precise information about the status of the environment. Thus, a contamination of the animals should require investigation and analysis of the environmental, meteorological and hydrological pollution in the areas where they live
Italian Foundry Contamination Due To Cs-137
In late October 2005 at the Beltrame plant in Susa Valley (Italy) a radioactive source was accidentally
burned in the blast furnace. The source was not discovered by the detectors at the entrance, evidently
because of some shielding effect. This caused the contamination of foundry dust, air intake system, and
of the filters. There was no dispersion in the environment and risks to workers. All contaminated
dust was collected in big bags and placed within containers waiting to know for their destination. The
global activity is now estimated at 4 GBq. Five different contamination scenarios, have been
analyzed, i.e., possible ways by which such an amount of radioactive material could have been
introduced into the foundry. The considered contamination (4 GBq) is compatible with the total
activity of some calibration sources. In both cases, Cs-137 is in the form of a quite small radioactive
source capsule, sealed and surrounded by a shielding material assembly, such as Pb. The source capsule
would have a quite high radioactive concentration, and then a total mass in the order of grams. It has
therefore to be classified – for sure – as a High Radioactivity Material, or, once it is inadvertently
thrown away, as High Level Waste (HLW), according to the Italian regulation (III Categoria). The lead
assembly shielding explains why the assembly passed through the check of the gamma sensor without
creating alarm
La selezione delle formazioni geologiche atte al deposito delle scorie radioattive
RIASSUNTO
La ComunitĂ Europea prevede lo smaltimento delle scorie radioallive mediante confinamento in depositi
geologici. A seconda della pericolositĂ d_el rifiuto il seppellimento avverrĂ a profonditĂ piĂą o meno grandi,
con un isolamento piĂą o meno marcato e prolungato dalla biosfera. Un indagine sulle caratteristiche
necessarie ad un sito per la sua elezione a deposito di scorie radioattive indica come primaria la stabilitĂ nel
tempo dell'area, dal punto di vista idrogeologico (circolazione delle acque sotterranee) e geodinamico. I
criteri di selezione delle formazioni geologiche adatte vengono analizzati in dettaglio: si basano sulle
proprietĂ fisico-chimiche della roccia, sullo spessore, omogeneitĂ , continuitĂ e profonditĂ della formazione,
sulla struttura geologica. I tipi di formazione identificati come piĂą affidabili sono principalmente tre:
formazioni argillose, depositi salini e basamenti cristallini. All'interno di ognuno di questi tre tipi, vengono
esaminate le formazioni geologiche nella ComunitĂ Europea piĂą idonee ad ospitare depositi di scorie. Per
ognuna di esse vengono posti in evidenza alcuni particolari criteri di selezione. r "iene esaminata la presenza e
distribuzione in Italia di formazioni geologiche adatte ad un possibile smaltimento delle scorie radioattive.
SUMMARY
European Community has planned the disposa/ of radioactive waste into J.!eo/ogica/ repositories. The depth
ofthe disposal and the degree ofisolationfrom environment will depend on the (ype ofwaste. f(ydrogeo/ogical
and geodynamical stability of the area are the main requirementsfor a waste di posai site. Se/ection criterio/or
geologica/ formations are examined in detail: they dea/ with the phisica/ and chemica/ properties of the rock,
the properties of formati on, and the geologica/ structure. Three formation (vpes have been se/ected: c/ays, sali
deposits and crysta/line formations. For each type, geologica/ formations in the European Community with
adequate properties are examined, putting into evidence particular se/ection criterio. The presence and
distribution of geologica/ fonnations in lta(v, appropriate /or radioactive waste di.~posal, is investiga/ed as
well
Magneto-convective effect on tritium transport at breeder unit level for the WCLL breeding blanket of DEMO
The Water-Cooled Lithium-Lead (WCLL) is one of the four breeding blanket concepts proposed by Europe in view of its DEMO reactor. The velocity field of the electrically conducting lead-lithium eutectic alloy inside the blanket is strongly influenced by the external magnetic field used for plasma confinement combined with buoyancy effect. The strength of the magnetohydrodynamics (MHD) effect and of the magneto-convective effect (MHD and buoyancy force) depends on the intensity of the magnetic field and its orientation with respect to the direction of the lead-lithium motion. This phenomenon significantly influences the resulting temperature and velocity fields, and therefore the tritium transport inside the breeding blanket. A multi-physics approach of a 3D tritium transport model is presented for a simplified geometry of the WCLL breeding blanket. In particular, advection-diffusion of tritium into the lead-lithium eutectic alloy, transfer of tritium from the liquid interface towards the steel, diffusion of tritium inside the steel, transfer of tritium from the steel towards the coolant, and advection-diffusion of diatomic tritium into the coolant, temperature field, velocity fields of both lead-lithium and water, buoyancy forces, and MHD effect have been included in this study. The tritium concentrations and the inventories inside the lead-lithium, in the Eurofer pipes and in the baffle, and in the water coolant have been evaluated
Radioactive Waste Management of Fusion Power Plants
This chapter outlines the attractive environmental features of nuclear fusion, presents an integral scheme to manage fusion activated materials during operation and after decommissioning, compares the volume of fusion and fission waste, covers the recycling, clearance, and disposal concepts and their official radiological limits, and concludes with a section summarizing the newly developed strategy for fusion power plant
Cyclosporin A markedly changes the distribution of doxorubicin in mice and rats
A; Dx, doxorubicin; AUC, area under the curve
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