There are currently very few examples of northern Canadian landscape architecture. There is even less literature on the subject. This design practicum follows a broad exploration of the Canadian North in an attempt to understand how the discipline of landscape architecture may insert itself as a profession capable of functioning in a northern environment. Key design issues specific to the North have been identified through a review of literature and personal experience working in the North, and have been categorized in three main areas: socio-economic, socio-cultural and physical environment. A framework of considerations for northern landscape architecture has been proposed and applied to the research process, supporting a holistic approach. A design has been proposed for the historic mine site of Port Radium, Northwest Territories. The design tests the applicability of landscape architecture in the North and follows the proposed framework, considering the history and future of the site from a socio-economic, socio-cultural and environmental perspective.

There are currently very few examples of northern Canadian landscape architecture. There is even less literature on the subject. This design practicum follows a broad exploration of the Canadian North in an attempt to understand how the discipline of landscape architecture may insert itself as a profession capable of functioning in a northern environment. Key design issues specific to the North have been identified through a review of literature and personal experience working in the North, and have been categorized in three main areas: socio-economic, socio-cultural and physical environment. A framework of considerations for northern landscape architecture has been proposed and applied to the research process, supporting a holistic approach. A design has been proposed for the historic mine site of Port Radium, Northwest Territories. The design tests the applicability of landscape architecture in the North and follows the proposed framework, considering the history and future of the site from a socio-economic, socio-cultural and environmental perspective.

Zugl.: München, Techn. Univ., Diss., 2006

Naturally occurring radioactive material (NORM) is a common feature in North Sea oil and gas production offshore but, to date, has been reported from only one production site onshore in the United Kingdom. This site, Wytch Farm on the Dorset coast, revealed high activity concentrations of lead-210 in metallic form but little evidence of radium accumulation. NORM has now been discovered at two further onshore sites in the East Midlands region of the UK. The material has been characterised in terms of its mineralogy, bulk composition and disequilibrium in the natural uranium and thorium series decay chains. In contrast to Wytch Farm, scale and sludge samples from the East Midlands were found to contain elevated levels of radium and radioactive progeny associated with crystalline strontiobarite. The highest radium-226 and radium-228 activity concentrations found in scale samples were 132 and 60 Bq/g, with mean values of 86 and 40 Bq/g respectively, somewhat higher than the mean for the North Sea and well above national exemption levels for landfill disposal. The two East Midlands sites exhibited similar levels of radioactivity. Scanning electron microscope imaging shows the presence of tabular, idiomorphic and acicular strontiobarite crystals with elemental mapping confirming that barium and strontium are co-located throughout the scale. Bulk compositional data show a corresponding correlation between barium-strontium concentrations and radium activity. Scales and sludge were dated using the 226Ra/210Pb method giving mean ages of 2.2 and 3.7 years, respectively. The results demonstrate clearly that these NORM deposits, with significant radium activity, can form over a very short period of time. Although the production sites studied here are involved in conventional oil recovery, the findings have direct relevance should hydraulic fracturing or fracking for shale gas be pursued in the East Midlands oilfield. Highly saline flowback fluid containing above regulation levels of radium has already been observed as a result of exploratory fracking operations in the North West s Bowland Shale and now appears a likely outcome if similar operations are conducted in the East Midlands. Barite (barium sulphate) coprecipitation is a cost-effective method for removing radium from solution. For the first time, reagent quantities for radium recovery by barite coprecipitation have been optimised in saline solutions of ionic strength (IS) 0.3 and 3 M. The process is highly effective, removing a maximum of ~90% radium in a single optimised coprecipitation step, but requiring substantially more sulphate at 3 M than at 0.3 M ionic strength to reach this maximum. It has been shown that, if left, the radiobarite precipitate will continue to remove radium by post-precipitation (recrystallisation). A pattern of diminishing returns in radium recovery by post- precipitation at each IS was observed; the rate was faster in the first 24 hours then dropped significantly over 14 days. After 14 days >80% of the radium was recovered, slightly more radium being removed at IS = 0.3 M. Therefore, if >90% radium recovery is sought, further co- and post-precipitation steps could be undertaken to approach the UK s 0.01 Bq/dm3 radium aqueous waste discharge exemption limit. However, compliance with UK s aqueous waste regulations would require multiple coprecipitation steps to recover >99.9% radium, which may not be feasible in practice. The Bowland Shale has high shale gas prospectivity and may be subject to further fracking operations in the future. Should local groundwaters mix with flowback fluid, there is potential for drinking water supplies to become contaminated. Baseline monitoring of groundwater was conducted in the region, so that comparisons may be made following potential fracking operations. The determined mean baseline for radium-226 and uranium-238 were 15.5 and 11.1 mBq/dm3 respectively, both below their respective notifiable drinking water level in the UK. In the majority of the groundwaters, barite is supersaturated and geochemical modelling has shown that a considerable proportion of the aqueous radium could precipitate in the Ba1-xRaxSO4 solid solution. A further increase in dissolved radium, barium and sulphate as a result of fracking will greatly increase the likelihood of concentrating the radium in barite scales, commonly found in oil and gas production equipment. What this means in terms of the potential NORM inventory is that Ra-containing NORM could manifest itself as fluid or solid waste.

This project’s goal is to evaluate the use of groundwater Rn as a tool for the search of deeply buried U deposits. To do so, the concentrations of major cations, anions, Rn, 4He, and 3H were measured in groundwater. Additionally, the abundance, composition, and distribution of radionuclides (U, Ra, 206Pb, 207Pb, 208Pb), were measured in soil and sandstone above the Denison Mines’ Phoenix Deposit (located at a depth of ~450 m). Rn was extracted from groundwater using mineral oil, and higher groundwater Rn radioactivity (average 0.13 Bq/g of water, n=10) was found in drill holes within ~100 meters of the Phoenix Deposit’s surface projection than in distal holes (average 0.072 Bq/g of oil, n=4). High Rn radioactivity is independent of the drill holes’ intersection with U ore, indicating that drilling did not transport significant amounts of Rn or parent isotopes to shallow depths. The water table is commonly within the Dunlop Member of the Athabasca sandstones, and groundwater Rn is positively correlated with average U concentrations obtained by modified aqua regia digestion of sandstones (analytical code 2AMS at the Saskatchewan Research Council) and also positively correlated with U in three-acid digestion of sandstones (analytical code 3AMS at the Saskatchewan Research Council). Diffusion models show Rn cannot travel significant distances, and so Rn is likely produced in MFd from the in-situ decay of U and Ra. 226Ra radioactivity was measured for B horizon soil samples (n=39) and sandstone samples (n=20) after a HCl leach followed with BaSO4 precipitation. An extraction efficiency for Ra of 28.2%±3.8%. was determined by comparing the soil BaSO4 precipitation procedure against unprocessed soils. Ra radioactivity in B horizon soil is lower than expected from U contents determined with INAA. Ra radioactivity is comparable to the values expected from INAA U concentrations (n=17) in sandstone, with exception to 4 Dunlop Member samples and 2 samples in the Read Formation and Bird Member. Ra in 4 of 5 samples in the Dunlop Member are 10-50% overabundant, perhaps resulting from Ra percolating downwards from soil. The proposed interpretation is consistent with lower than expected Ra radioactivity of B horizon soil. Ra is 260% and 420% overabundant in the two samples from the Read Formation and the Bird Member (1 each), suggesting upward migration of Ra from the U deposit. Low solute concentration and a neutral-weakly alkaline pH of shallow groundwater in the study area appears to prevent significant travel of Ra ions through groundwater by means of ion absorption competition. Pb isotopic compositions were determined using an ICP-MS for sandstones and soil via three different leaches; 0.02 N HBr, 2.7 N HCl, and concentrated HBr. Overall, Pb isotopic compositions of MFd (n=5) and B horizon (n=10) are similar, supporting the percolation of acidic surface waters through soil. One sample from RD (among 4 samples) show high 206Pb, suggesting an upward migration of 206Pb from the deposit. The ratios of 4He/3He in ground water ranged between 0.95-1.07; typical of groundwater-atmosphere interaction. The lateral flow of groundwater at deep levels can explain the absence of higher 4He/3He.

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Includes bibliographical references. / M.S.

I början av 1900-talet ansågs radium vara ett försäljningsargument för olika hushållsartiklar. Föreliggande studies syfte var att undersöka hur förhållandet till radium i hushållsnära varor såg ut i Sverige under tidsperioden 1900–1930. Syftet var även att undersöka vilka argument, om helbrägdagörande och vetenskapliga, som gavs för att sälja dessa produkter. Ur detta syfte skapades följande frågeställningar. 1. Hur skildrades radiumets olika aspekter i artiklar och annonser? 2. Vilka psykologiska- och medicinska tillstånd beskrevs dessa produkter vara bra för? 3. Vilka anspråk på medicinsk och vetenskaplig kunskap legitimerade användandet av dessa produkter? 4. På vilket sätt framkom det i annonser och artiklar hälsorisker med användandet? Som källmaterial användes artiklar och annonser ur två dagstidningar. Utöver dessa användes ett antal artiklar skrivna av kemisten John Landin. Materialet tolkades ur media- och medicinhistorisk synvinkel. Med tematisk analys skapades fem huvudkategorier: medicinska, skönhets-, psykologiska, vetenskapliga och strukturella argument för att använda radioaktiva hushållsprodukter. Resultatet pekade på att produkterna legitimeras genom bland annat medicinsk och vetenskaplig expertis. Radiumets nyttoaspekter framhölls, då radiumet sades bota allehanda sjukdomar. Inga risker framhölls med användandet. Därefter diskuteras studiens resultat kopplat till ställda frågeställningar och tidigare forskning samt samtidsrelevans. Slutligen diskuteras undersökningens styrkor och svagheter. / At the beginning of the 20th century, radium was considered a selling point for various household items. The purpose of the present study was to investigate how the relationship to radium in household goods looked like in Sweden during the period 1900-1930. The purpose was also to investigate what arguments, about healing and scientific, were given to sell these products. For this purpose, the following questions were created. 1. How is radium described in articles and advertisements? 2. What psychological and medical conditions are these products described to be good for? 3. What claims to medical and scientific knowledge legitimized the use of these products? 4. In what way do advertisements and articles presented any health risks with their use? As source material, articles-, and advertisements from two daily newspapers were used. In addition, several articles written by the chemist John Landin were used. The material was interpreted from media and medical historical point of view. With thematic analysis, five main categories were created: medical, beauty, psychological, scientific, and structural arguments for using radioactive products. The results indicated that the products were legitimized through, among other things, medical and scientific expertise. The usefulness of radium was emphasized when radium was said to cure all kinds of diseases. No risks were emphasized with the use. Then the results of the study are discussed in connection with questions asked and previous research as well as contemporary relevance. Finally, the strengths and weaknesses of the survey are discussed.

The main aim of this work was to investigate the extent of uranium and radium -fixation and mobilization at the interface of mining influenced surface water and sub-hydric soils, sediment and plant detritus. A freshwater ecosystem (stream channels in an alder swamp forest – Alno-Lemnetum with low residence time shallow ponds) developed directly below a mining site (Neuensalz) and influenced by uranium containing water served as investigation site for the identification of possible fixation and mobilization mechanisms. In addition, investigations were carried out on sediments in a water reservoir downstream of the examined abandoned mining site. It could be shown, that radium concentrations of the examined surface water (2001 – 2004) are only slightly higher compared to the range of geogenic levels for German surface waters, and that its activity concentrations decreased along the investigated flow path. In contrast, uranium concentrations are well above geogenic levels and the concentration level stays high along the whole water pathway through the study area. The U-238:Ra-226 ratio of the examined surface water from the spring to a pond outflow significantly increased. The uranium chain activity concentrations in the sediments determined in this study partly exceeded considerably the regional geogenic level. For the sediment water the 238U: 226Ra ratio in the first part of the flow path is significantly shifted in favor of radium while in the second part the ratio is shifted in favor of uranium. There were indications that the dissolved uranium is transported in the form of soluble carbonate complexes. Radium however is rather fixed under dominantly oxidizing conditions along the mainly turbulent mixed shallow water pathway. The fixation of uranium and radium in the upper section of the pathway (direct below the spring) was found to be inorganically, whereas in the second part organic bonds are more indicated. The influence of allochthonous organic carbon as main metabolic energy source for low order lotic ecosystems on the fixation of uranium was investigated by analyzing, the effects of leaves (coarse particulate organic matter: CPOM) and their degradation products (mainly fine particulate organic matter: FPOM and biofilms etc.). It was found that the highly mobile fraction of uranium in the water pathway, preferably present under the given conditions in the form different uranyl-carbonato-complexes, is efficiently fixed on fresh organic plant material (plant litter, leaves) in the first steps of organic matter decomposition within a few days. But it also can be immobilized relatively stable. It was also found that CPOM is a temporary sink for uranium, which may be sedimented depending on the turbulence flow and discharge. This may contribute to the directional removal of uranium from the water into the sediment. Finally this work analyzed the conditions in the pelagic and benthic zone of the Neuensalz pre dam of the Pöhl reservoir, which is located downstream of the mining site. It presents a periodically stagnant water body with seasonally continuous sedimentation, a possible stable sink of uranium and products of radioactive decay in early diagenesis. Water samples of the pelagic zone and undisturbed sediment cores were taken and analyzed during winter stagnation. The results are discussed in front of seasonal changes in water chemistry and load data. U-238 and Ra-226 showed a culmination of activity concentrations in the sediment horizons from 25 to 35 cm depth, in particular at a centrally located sampling point (K3). At this point highest activity concentrations of 238U were found with a median value of 770 Bq*kg-1 at a depth of 30 cm. At the same location 226Ra shows activity concentrations of 250 Bq*kg-1(median). Based on the Cs-137 dating method a sedimentation rate of 1.5 cm*yr-1 was calculated for the pre-dam Neuensalz sediment. On average sedimentation rates for 238U of 3,7 ± 1,1 kBq*m-2*yr-1 and for 226Ra of 3,5 ± 0,5 kBq*m-2*yr-1 were calculated. Furthermore, a total uranium stock of 68 ± 6 kg per hectare in the sediment was estimated. In connection with a sedimentation period of 23 years, the uranium inventory in the sediments would correspond to a portion of approx. 18 % of the uranium feed by the water influx estimated for the same period. This estimation did not take into account a geogenic portion and other sources like fertilizer. For radium, the situation is reversed. An extrapolation of the cumulative load for the same period results in a lower value by almost a factor of 100 compared to uranium. This compares with a radium inventory in the sediment, which is about 15 times higher than the projected load. This leads to the conclusion that in addition to the supply from the mining legacy also the geogenic background and/or discontinuous particulate import (via storm water stream runoff etc.) has to be considered. The analysis of the bonding stability and related potential mobilization of the sedimentary uranium using sequential chemical extraction shows that most of the uranium is found in the organic fraction over the entire sediment layer, which may be identified as organically bound or as uraninite. In conclusion not only radium is immobilized near to the source but also a relevant share of uranium is permanently fixed even in/on durably deposited organic matter despite eu-trophic conditions with high nitrate load, traceable in deeper sediment layers due to e.g intensive land use. / Hauptziel der vorliegenden Arbeit war die Untersuchung des Umfangs der Festlegung bzw. Mobilisierung von Uran und Radium an der Grenzfläche von Bergbau beeinflußtem Oberflächenwasser und subhydrischen Böden, Sedimenten sowie Bestandsabfall (Detritus). Als Untersuchungsgebiet zur Identifizierung entsprechender Fixierungs- und Mobilisierungsmechanismen diente ein Süßwasser - Ökosystem (Bach in einem Erlenbruchwald – Alno-Lemnetum – und integrierte flache Teiche mit geringer Verweilzeit) unterhalb eines ehemaligen Uranerzbergbau-Gebietes (Neuensalz), das von uranhaltigem Wasser durchströmt ist. Darüber hinaus Sedimentanalysen eines periodisch stagnierenden Wasserkörpers (Vorsperre der Talsperre Pöhl) im Abstrombereich der untersuchten Bergbaualtlast vorgenommen. Es konnte gezeigt werden, dass die Radiumkonzentration des Oberflächenwassers (2001-2004) geringfügig über der des geogenen Niveaus für deutsche Oberflächenwässer liegt und dass die entsprechende Aktivitätskonzentration von Radium entlang der untersuchten Fließstrecke beginnend mit einer Quelle an einem Tailingdamm deutlich abnimmt. Dagegen liegen die Urankonzentrationen des Oberflächenwassers deutlich über dem geogenen Hintergrund. Seine Aktivitätskonzentrationen bleiben entlang der Fließstrecke weitgehend stabil. Das 238U:226Ra-Verhältnis des Oberflächenwassers wird sich entlang der Fließstrecke von der Quelle unterhalb des Tailingdammes bis zum Abfluss aus der ersten, schwächer durchflossenen kleinen Senke (Forellenteich) erhöht. Die in dieser Arbeit ermittelten Aktivitätskonzentrationen der untersuchten Nuklide der Sedimente lagen zum Teil erheblich über dem geogenen Niveau der Region. Das 238U:226Ra-Verhältnis des Bachsediments ist im ersten Teil der Fließstrecke deutlich zugunsten des Radiums verschoben, während es im zweiten Teil zugunsten von Uran verschoben ist. Dies weist darauf hin, dass das gelöste Uran in Form carbonatischer Komplexe transportiert wird. Radium wird dagegen unter den vorherrschenden oxidierenden Bedingungen entlangder Fließstrecke eher fixiert. Für die Festlegung von Uran und Radium wurde im oberen Teil der Fließstrecke (direkt unterhalb der Quelle) eher auf anorganische Bindungen geschlossen, während die Fixierung im zweiten Teil der Fließstrecke eher organischer Natur ist. Da im Oberlauf von Fließgewässern allochthoner organischer Kohlenstoff die wesentliche die Energiequelle für alle Ökosystemfunktionen bildet und eine besondere Funktion mit Blick auf Untersuchungsziel vermutet werden kann, wurde die Wirkung von Laub (grob- organisches Material: CPOM) und seinen Abbauprodukten (fein-partikuläres organisches Material: FPOM, Biofilm usw.) auf die Fixierung von Uran analysiert. Es wurde festgestellt, dass das im Wasserpfad sehr mobile Uran, welches unter den gegebenen Bedingungen vorzugsweise in verschiedenen Uranyl-Carbonato-Komplexen vorliegt, nicht nur an frischer organischer Substanz pflanzlichen Ursprungs (Bestandesabfall, Laub) im Verlauf biologischen Abbaus effizient gebunden und festgelegt wird, sondern auch sehr stabil immobilisiert werden kann. Es wurde auch ermittelt, dass CPOM ein temporärer Speicher für Uran ist, welcher je nach Fließgeschwindigkeit sedimentieren und damit zum gerichteten Transfer von Uran aus dem Wasser in das Sediment beitragen kann. Der anteilige Austrag über das verstärkt gebildete DOC über den Laubeintrag ist relativ gering. Schließlich wurden die Verhältnisse mit Bezug zur Fragestellung in der pelagischen und benthischen Zone der Vorsperre Neuensalz der Talsperre Pöhl analysiert, die stromabwärts des Bergbaugebietes anschießt. Die Vorsperre stellt einen periodisch stagnierenden Wasserkörper mit saisonaler kontinuierlicher Sedimentation dar und damit eine mögliche stabile Senke für Uran und seine radioaktiven Zerfallsprodukte in der Frühdiagenese. Wasserproben der pelagischen Zone und ungestörte Sedimentkerne wurden in der Phase der Winterstagnation entnommen, analysiert und unter Berücksichtigung saisonaler Unterschiede bezüglich Wasserchemie und Frachtdaten disskutiert. Für U-238 und Ra-226 zeigt sich eine Kulmination der Aktivitätskonzentration in den mittleren Sediment- Horizonten von 25-35 cm Tiefe, insbesondere an der Probenahmestelle K3. Dort fanden sich auch die höchsten Aktivitätskonzentrationen der Vorsperre für 238U mit einem Medianwert von 770 Bq*kg-1 in einer Tiefe von 30 cm. Für Ra-226 fand sich am selben Ort eine Aktivität von 250 Bq*kg-1 (Median). Anhand der Datierung mithilfe der Cs-137 Methode wurde für das Sediment der Vorsperre Neuensalz eine Sedimentationsrate von 1,5 cm*a-1 errechnet. Für Uran ergab sich eine Sedimentationsrate von 3,7 ± 1,1 kBq*m-2*a-1 und für Ra-226 eine solche von 3,50 ± 0,5 kBq*m-2*a-1. Darüber hinaus wurde die im Schnitt ca. 40 cm mächtigen Sedimente ein Uranvorrat von 68 ± 6 kg pro Hektar bilanziert. In Verbindung mit der Dauer des Bilanzzeitraumes der Sedimentation (23 Jahre) entspräche das in der Vorsperre vorgefundene Uraninventar einem Anteil von ca. 18 % der für diesen Zeitraum abgeschätzten Uranfracht im Wasserzufluss, wobei der geogene Anteil des Urans und die Ausbringung von Phosphatdüngemitteln in den Sedimenten noch nicht berücksichtigt ist. Für Radium sind die Verhältnisse umgekehrt. Wenn aus den gegenwärtigen Aktivitätskonzentrationen im Zufluss auf eine kumulative Fracht für den 23-jährigen Bilanzierungs- bzw. Betrachtungszeitraum hochgerechnet wird, ergibt sich ein fast um den Faktor 100 geringerer Wert, verglichen mit Uran. Dem steht ein Radiuminventar im Sediment gegenüber, welches etwa 15-mal größer als diese hochgerechnete Fracht ist. Daraus ist abzuleiten, dass neben der relativ geringen wassergelösten Zufuhr aus der Bergbaualtlast dem gegogenen Hintergrund im sedimentierenden Substrat sowie diskontinuierlich Partikel (über Regenwasserabfluss) Bedeutung beizumessen ist. Bei der Analyse der Bindungsverhältnisse des sedimentären Urans (sequentielle Extraktion) wurde der größte Anteil des Urans im Sediment als Uraninit bzw. als organisch gebunden identifiziert. Insgesamt ist zu schließen, dass nicht nur Radium in der Nähe von Quellen immobilisiert wird, sondern auch Uran eine dauerhafte Fixierung in ständig abgelagertem organischem Material erfährt. Diese Fixierung ist trotz eutropher Bedingungen mit hoher Niratbelastung stabil und in tieferen Sedimentschichten nachweisbar.

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-04-08T12:24:41Z No. of bitstreams: 0 / Made available in DSpace on 2016-04-08T12:24:41Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-04-08T12:24:41Z No. of bitstreams: 0 / Made available in DSpace on 2016-04-08T12:24:41Z (GMT). No. of bitstreams: 0 / Os radionuclídeos naturais das séries radioativas do 238U, 235U e 232Th são frequentemente utilizados como traçadores em estudos ambientais para a compreensão da dinâmica que ocorre no ambiente marinho e terrestre, como por exemplo, em pesquisas de processos oceânicos e gerenciamento da região costeira. No ambiente marinho, estes radionuclídeos podem ser empregados para estimar fluxos biogeoquímicos de partículas e de nutrientes que ocorrem tanto na coluna dágua, quanto nos sedimentos. Várias pesquisas aplicam a distribuição e o respectivo desequilíbrio dos radionuclídeos naturais no meio ambiente, inclusive em modelos geocronológicos para se obter informações históricas em testemunhos sedimentares. Nesse estudo, realizou-se a caracterização radioquímica das distribuições de 226Ra, 228Ra e 210Pb de uma coluna sedimentar denominada 1B (248 cm de comprimento), coletada na Baía do Almirantado, Antártica. A metodologia utilizada incluiu a lixiviação ácida de amostras de sedimentos, seguida de separação radioquímica sequencial de 226Ra e de 228Ra pela co-precipitação com Ba(Ra)SO4 e de 210Pb pela co-precipitação com PbCrO4. Todas as medidas foram realizadas pela contagem alfa e beta total dos precipitados obtidos, em um detector proporcional de fluxo gasoso de baixa radiação de fundo. As concentrações de atividade de 226Ra e 210Pb foram empregadas para se estimar a atividade de 210Pbnão-suportado presentes no perfil sedimentar 1B. Considerando-se as concentrações de atividade de 210Pbnão-suportado obtidas e a aplicação do modelo CIC(Constant Initial Concentration), foi possível determinar a taxa de sedimentação de 0,59±0,05 cm/ ano. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP