<p> The interaction of tritium with aluminum, copper, stainless steel, and gold plated substrates was studied using a low-pressure, argon plasma, as well as thermal desorption spectroscopy. These experimental methods allowed the influence of modifying metal surfaces on the absorption and adsorption of tritium to be measured. Stainless steel surfaces were modified by mechanical polishing, electropolishing, selective oxidation pre-treatments, and gold plating. The only surface modification performed on aluminum and copper samples was gold plating.</p><p> Use of the low-pressure plasma constitutes a novel approach to studying tritium migration and to measuring the quantity of adsorbed tritium. The migration of tritium was inferred from experiments, where a metal sample was exposed to a pulsed plasma. In such a method, tritium migration to the surface in between each pulse influences the quantity of tritium removed during subsequent plasma pulses. The results of these measurements indicated that the mechanism for tritium migration to the surface was limited by diffusion out of the underlying metal lattice. The measured rate of tritium migration to the surface does not appear to depend strongly on the metal type or surface modification. </p><p> Thermal desorption experiments were used to measure the influence of modifying metal surfaces on the total absorption of tritium. Thermal desorption involves heating samples to high temperatures for protracted periods of time, in order to remove all tritium contained within the metal lattice. These measurements indicated that modifying a metal surface significantly influences the total absorption of tritium during room temperature (25&deg;C) exposures. </p><p> Finally, a quantitative tritium migration model (QTRIMM) was developed in this work to describe the transport of the isotope through metal lattices. Additionally, QTRIMM includes a condition that relates the tritium concentrations adsorbed to the surface to the concentrations within the metal lattice. This model represents a major step forward in describing the migration of tritium through metal substrates, as many previous transport models have not included a condition for tritium adsorption. As demonstrated in this study, QTRIMM describes the measured data reasonably well.</p>

This work involves the design, synthesis, and formulation of organic second-order nonlinear optical and photorefractive materials. The second-order nonlinear optical work is divided into two sections. The first section focuses on the design and synthesis of high glass transition temperature aromatic polyesters for high temperature nonlinear optical applications. The polyesters are based on azo dye derivatives of resorcinol and 3,3'-ethylenedioxydiphenol. These diphenols could be polymerized with 5-t-butylisophthaloyl dichloride using mild solution or interfacial polycondensation procedures. The incorporation of the t-butyl groups in the polymer backbone resulted in a significant increase in glass transition temperature and more importantly solubility. The ethylene linkage present in the 3,3'-ethylenedioxydiphenol had the effect of lowering the glass transition temperature while providing a small increase in solubility. The resulting polymers were soluble in common organic solvents and had glass transition temperatures ranging from 89°C to 171°C. These polymers will be characterized for their second-order nonlinear optical properties in the near future. The second section on nonlinear optical materials focuses on the synthesis and characterization of a model compound for future self-assembling nonlinear optical molecules and polymers. The synthesis of dispiro[indane-2,3'-piperazine-6',2''-indane]-2',5'-dione via the direct thermolysis and dimerization of methyl-2-amino-indan-2-oate hydrochloride was accomplished. The crystal structure of this compound showed the necessary hydrogen bonding needed for the construction of an anisotropic, noncentrosymmetric second-order nonlinear optical material. The photorefractive work involved the formulation of guest-host polymer composites that demonstrated the photorefractive effect. The polymer composites are composed of poly(N-vinylcarbazole), 2,4,7-trinitrofluorenone and a second-order nonlinear optical azo dye. The composites and could be processed into thick films suitable for photorefractive measurements by plasticizing with N-ethylcarbazole. These materials could be electric-field poled at room temperature and showed high diffraction efficiencies ranging from 1% to 5%. The photoisomerization of the azo dyes to produce a competing diffraction signal was found to be polarization sensitive. Thus, the photorefractive effect could be isolated and studied independently by selecting the appropriate polarization. The photoisomerization can be avoided altogether by tailoring the azo dyes so that their absorbance is minimal at the frequency of the laser light. It was possible to perform asymmetric two-beam coupling when the photoisomerization was minimal.

Contained in this dissertation is an analysis of the fundamental chemistry of the f-block elements with oxygen donor ligands in ionic liquids. This work focuses heavily on the structures of the crystalline phases that form when lanthanides and actinides react with either phosphonates or borates in an ionothermal flux. It will be demonstrated in this work that this flux method is a valuable means of preparing new materials that would otherwise be unattainable using more conventional hydrothermal or solvothermal flux methods. The first project in this work focuses on the ionothermal flux synthesis of a series of new uranium phosphonates. Since the hydrothermal and solvothermal flux syntheses of uranium phosphonates had previously been extensively studied, this work provided a valuable proof of concept since there was a large body of reported structures to compare the products of the ionothermal flux reactions against. It was found that the topologies of the resulting crystalline phases were dictated equally by the choice of the ligand (e.g. aryl monophosphonate, alkyldiphosphonate, etc.), the choice of the flux method, and the choice of ionic liquid if an ionothermal flux was used. In the second project, a new series of trivalent f-element borates was synthesized using an ionothermal flux. While it was expected that the ionic liquid would act as both the solvent and the template in the synthesis of three-dimensional borate framework materials, what was actually observed was the formation of an isomorphous series of molecular tetranuclear borate cluster compounds. This is further evidence that an ionothermal flux may actually be responsible for limiting the dimensionality of structure topologies rather than facilitating the formation of templated extended networks. / A Dissertation submitted to the Department of Chemistry and Biochemistry in partial fulfillment of the Doctor of Philosophy. / Fall Semester 2015. / September 15, 2015. / Includes bibliographical references. / Thomas E. Albrecht-Schmitt, Professor Directing Dissertation; Samuel L. Tabor, University Representative; Michael Shatruk, Committee Member; Susan E. Latturner, Committee Member.

Since stars retain signatures of their galactic origins in their chemical compositions, we can exploit the chemical abundance distributions that we observe in stellar systems to put constraints on the nature of their progenitors. In this thesis, I present results from three projects aimed at understanding how high resolution spectroscopic observations of nearby stellar systems might be interpreted. The first project presents one possible explanation for the origin of peculiar abundance distributions observed in ultra-faint dwarf satellites of the Milky Way. The second project explores to what extent the distribution of chemical elements in the stellar halo can be used to trace Galactic accretion history from the birth of the Galaxy to the present day. Finally, a third project focuses on developing an input optimization algorithm for the second project to produce better estimates of halo accretion histories. In conclusion, I propose some other new ways to use statistical models and techniques along with chemical abundance distribution data to uncover galactic histories.

The focus of this doctoral thesis is the redox chemistry involved in radiation induced oxidative dissolution of spent nuclear fuel and UO2 (as a model substance for spent nuclear fuel). It is shown that two electron oxidants are more efficient than one electron oxidants in oxidative dissolution of UO2 at low oxidant concentrations. Furthermore, it is shown that H2O2 is the only oxidant that has to be taken into account in radiation induced dissolution of UO2 under deep repository conditions (granite groundwater dominated by α-radiolysis). Previously determined rate constants for oxidation of UO2 by H2O2 and O2, and rate constants for dissolution of U(VI) from the surface are successfully used to reproduce numerous UO2 dissolution rates reported in the literature. The impact of reactive solutes (Fe(II)(aq), 2-propanol and chloride) and Pd-inclusions (as a model for ε-particles) in combination with H2, on radiation induced oxidative dissolution of UO2 is investigated. It is shown that both the studied reactive solutes (under oxygen free conditions) and the combination of Pd inclusions and H2 inhibit the dissolution. Calculations (based on the fuel inventory) show that 1 µM Fe(II)(aq) decreases the dissolution rate by a factor of ~50 and that 1 ppm surface coverage of ε-particles is sufficient to completely stop the dissolution of 100 year old fuel (assuming 40 bar H2).The dissolution behavior of NpO2 and PuO2 in H2O2 containing aqueous solution without complexing agent is studied and compared to UO2. Based on the measured dissolution rates, we would not expect the dissolution of the actinides to be congruent. Instead, in a system without complexing agent, the rates Np and Pu are expected to be lower than the U release rate. The effect of ionizing irradiation on the UO2 reactivity is studied in order to elucidate the effect of self-irradiation on the reactivity of the spent fuel matrix. It is shown that a threshold dose must be achieved before any effect of irradiation can be seen. Beyond the threshold the reactivity seems to increase with increasing dose. Furthermore, the effect appears to be permanent. The effect of particle size on the reactivity of UO2 powder is studied in view of proposed theories suggesting a particle size dependence of both the pre-exponential factor and the activation energy for redox reactions. The rate constant and activation energy for oxidation of UO2 by MnO4- seems to agree with the proposed equations. The radiation chemical synthesis of UO2 nanoparticles is studied. It is shown that U(VI) released by dissolution of spent nuclear fuel could be reduced to UO2 nanoparticles.These particles could, due to their high reactivity towards H2O2, act as oxidant scavenger in a future deep repository for spent nuclear fuel. / Denna doktorsavhandling behandlar redoxprocesser involverade i strålnings­inducerad oxidativ upplösning av använt kärnbränsle och UO2 (som modellsubstans för använt kärn­bränsle).Detta arbete visar att två-elektron oxidanter är mer effektiva än en-elektron oxidanter i oxidativ upplösning av UO2 vid låga oxidantkoncentrationer. Dessutom visas, på kinetiska grunder,att H2O2 är den enda oxidant som måste tas hänsyn till vid stålningsinducerad oxidativ upplösning av UO2 under djupförvarsförhållanden (granitiskt grundvatten dominerat av α-radiolys). Tidigare bestämda hastighets­konstanter för oxidation av UO2 med H2O2 och O2, samt hastighets­konstanter för upplösning av U(VI) från ytan har framgångrikt använts för att återskapa UO2 upplösningshastigheter rapporterade i litteraturen. Inverkan av reaktiva ämnen i vattenfas (Fe(II)(aq), 2-propanol och klorid) samt av Pd-inneslutningar (som modell av ε-partiklar) i UO2 matrisen i kombination med H2, på strålningsinducerad upplösning av UO2 har studerats. Studien visar att både de reaktiva ämnena i vattenfasen (under syrefria förhållanden) och Pd- inneslutningar i kombination med H2 hämmar upplösningen. Beräkningar (baserade på ett bränsle­inventarie) visar att 1 µM Fe(II)(aq) minskar upplösningshastigheten med en faktor ~50 samt att 1 ppm ytbeläggning av ε-partiklar är tillräckligt för att effektivt stoppa uppslöningen av 100 år gammalt bränsle (vid 40 bar H2).Upplösning av NpO2 och PuO2, i jämförelse med UO2,har studerats i vatten­lösning innehållande H2O2 utan komplexbildare. Baserat på de uppmätta upp­lösnings­hastigheterna förväntas upplösningen av dessa aktinider från UO2-bränsle vara inkongruent. I ett system utan komplexbildare kan NpO2 odh PuO2 upplösningshastighetern förvantas vara lägre än UO2 upplösningshastigheten. Effekten av joniserande strålning på reaktiviteten hos UO2 har studerats för att klargöra effekten av egen-bestrålning. Studien visar att dosen måste nå ett visst tröskelvärde innan någon effekt på reaktiviteten kan observeras. Vid doser över tröskelvärdet ökar reaktiviteten med ökande dos. Effekten verkar vara permanent. Partikelstorlekens inverkan på reaktiviteten hos UO2 pulver har studerats med utgångspunkt i föreslagna samband mellan partikelstorlek och pre-exponentiell faktor och mellan partikelstorlek och aktiveringsenergi. Studien visar att hastighets­konstanten och aktiveringsenergin för reaktionen mellan UO2 och MnO4- överenstämmer med de föreslagna sambanden. Stålningskemisk syntes av UO2 nanopartiklar har studerats. Studien visar att U(VI) frigjort genom upplösning av använt kärnbränsle i ett djupförvar kan reduceras till UO2 nanopartiklar. Dessa partiklar kan, på grund av sin höga reaktivitet med H2O2, fungera som infångare av oxidanter i ett framtida djupförvar för använt kärnbränsle. / QC 20100908

<p>I det svenska djupförvaret för kärnbränsle ska kompakterad bentonit användas som barriär mellan kopparkapslar med utbränt kärnbränsle och berget. I kontakt med vattenförande sprickor kan bentonitbarriären under vissa omständigheter avge montmorillonitkolloider. Förutom att barriärens egenskaper urholkas pga förlusten av material kan kolloiderna, om de är stabila, underlätta transporten av sorberade radionuklider ut mot biosfären.</p><p>Den här studien fokuserar på att undersöka vilka effekter grundvattenkemin har på montmorillonitkolloiders stabilitet. Grundvattnets sammansättning, pH och jonstyrka, kommer sannolikt att förändras under djupförvarets livslängd, delvis pga inträngandet av glactialt smältvatten. Initialt kommer omgivande berg att värmas upp pga värmealstring från det radioaktiva sönderfallet i det utbrända kärnbränslet. Effekterna av pH, jonstyrka och temperatur på montmorillonitkolloiders stabilitet har analyserats genom att följa hur kolloiderna aggregerar med tiden. Minskningen av partikelkoncentration med tiden mättes med Photon Correlation Spectroscopy (PCS).</p><p>Aggregationsexperimenten visar att, vid ett givet pH och en given temperatur, ökar hastighetskonstanten för aggregation med ökande jonstyrka. Kritiska koaguleringskoncentrationen (CCC) för NaCl och CaCl2 för Na-montmorillonit och Ca-montmorillonit beräknas utifrån ett samband mellan hastighetskonstanterna och jonstyrkan.</p><p>Hastighetskonstanten för aggregation minskar med ökande pH eftersom ytpotentialen ökar. Effekten blir tydligare vid högre jonstyrkor och högre temperaturer, men kan däremot inte observeras vid låga temperaturer.</p><p>Temperatureffekten på bentonitkolloidernas stabilitet är pH-beroende. Vid pH≤4 ökar hastighetskonstanten för kolloidaggregation med ökande temperatur, oavsett jonstyrka.Vid pH≥10 minskar hastighetskonstanten med ökande temperatur. I mellanliggande pH-område minskar hastighetskonstanten för aggregation med ökande temperatur, förutom vid den högsta jonstyrkan, där den ökade. Beräkningar baserade på DLVO-teori matchar de experimentella resultaten.</p> / <p>In deep geological repositories in Sweden, encapsulated nuclear waste will be surrounded by compacted bentonite in the host rock. In future contact with water-bearing fractures, this bentonite barrier can release montmorillonite colloids under certain conditions. This process can lead to loss of buffer material. Furthermore, these colloids, if stable, may facilitate the transport of associated radionuclides towards the biosphere. Colloid stability is determined by groundwater chemistry.</p><p>This study addresses the effects of groundwater chemistry on the stability of montmorillonite colloids. During the lifetime of the repository, the pH and ionic strength of the groundwater are expected to vary, partly due to intrusion of glacial melt water. Initially, the temperature will be higher in the surrounding host rock due to heat released from radioactive decay in the spent nuclear fuel. The effects of these parameters on the stability of montmorillonite suspensions were evaluated by studying the aggregation kinetics. The change in particle concentration with time was monitored by Photon Correlation Spectroscopy (PCS).</p><p>Aggregation kinetics experiments showed that for a given pH and temperature, the rate constant for colloid aggregation increased with increasing ionic strength. The relationship between the rate constant and the ionic strength allowed the NaCl and CaCl2 critical coagulation concentration (CCC) for Na- and Ca-montmorillonite to be determined.</p><p>The aggregation rate constant decreased with increasing pH as the surface potential increased. This effect became more pronounced at higher ionic strengths and higher temperatures but could not be observed at low temperature.</p><p>The effect of temperature on the stability of the suspensions is pH-dependent. At pH≤4, the rate constant for colloid aggregation increased with increasing temperature, regardless of ionic strength. At pH≥10, the aggregation rate constant decreased with increasing temperature. In the intermediate pH interval, the aggregation rate constant decreased with increasing temperature except at the highest ionic strength, where it increased.</p><p>The experimental results were in agreement with DLVO calculations.</p>

<p>Denna licentiatavhandling behandlar effekten av två inneboende egenskaper (fissions produkter och egenbestrålning) hos utbränt kärnbränsle på hastigheten för strålningsinducerad upplösning av bränslematris (UO2). I ett framtida djupförvar kommer det utbrända kärnbränslet att deponeras 500 meter ner i berggrunden i en reducerande miljö. Under dessa förhållanden är UO2-matrisen själv en av de skyddande barriärerna mot frigörande av radionuklider, på grund av dess låga löslighet. När bränslet kommer i kontakt med vatten kommer U(IV) att oxideras till U(VI) av radiolysprodukter från vattnet och lösligheten för bränslematrisen kommer därmed att öka betydligt. </p><p>De flesta tidigare studier har utförts på obestrålad UO2 som skiljer sig signifikant från utbränt kärnbränsle. I utbränt kärnbränsle är de flesta fissionsprodukterna och neutronaktivieringsprodukterna radioaktiva och bränslet kommer därför bli bestrålat av sig självt. Effekten av joniserande strålning på reaktiviteten för UO2(s) har undersökts här. UO2 (pulver och fragment av en kuts) bestrålades i en 60Co γ-källa eller framför en elektronaccelerator varpå reaktiviteten för UO2 studerades genom oxidation av UO2 med MnO4 -. Det visade sig att reaktiviteten för UO2 ökar när det blir bestrålat för första gången (<20 kGy). Effekten ökar med ökande dos tills den når ett maxvärde ~1.3 gånger reaktiviteten för obestrålad UO2 vid torrbestrålning. Vid våtbestrålning ökar en dos på 140 kGy reaktiviteten 2.5 gånger. Effekten verkar vara permanent. </p><p>Tidigare studier har visat att H2O2 är den viktigaste oxidanten för upplösning av utbränt kärnbränsle under djupförvarsförhållanden. I vätgasatmosfär, som förväntas i ett djupförvar, har det visat sig att upplösningshastigheten är långsammare. Det har delvis förklarats med reaktionen mellan H2O2 och H2, som är väldigt långsam utan katalysator. Den katalytiska effekten av UO2 på den reaktionen har undersökts och det visades att den inte katalyseras av UO2. </p><p>En annan möjlig katalysator för reaktionen är ε-partiklar (ädelmetallpartiklar bestående av Mo, Ru, Tc, Pd och Rh) som bildats av fissionsprodukterna. Pd är en välkänd katalysator för reduktion med H2. Den eventuella katalytiska effekten av Pd har undersökts här. Även en eventuell katalytisk effekt av Pd på reduktionen av U(VI) med H2 undersöktes, både i vattenfas och i UO2-kutsar innehållande olika mängder Pd (som en modell för ε-partiklar).</p><p> Vi fann att Pd har en katalytisk effekt på reaktionen mellan H2O2 och H2 och andra ordningens hastighetskonstant är bestämd till (2.1±0.1)x10-5 m s-1. Pd har också en katalytisk effekt på reduktionen av U(VI) med H2 både i vattenlösning, hastighetskonstant (1.5±0.1)x10-5 m s-1, och i den fasta fasen. Hastighetskonstanten för processen i fast fas är 4x10-7 m s-1 och 7x10-6 m s-1 för kutsar med 1 respektive 3 % Pd. Dessa värden är väldigt nära diffusionsgränsen för den här typen av system. Den katalytiska effekten i den fasta fasen visar att upplösningen för 100 år gammalt bränsle kan stoppas helt. Vid 40 bar H2 krävs 10-20 ppm ädelmetallpartiklar och med 1 % ädelmetallpartiklar räcker det med 0.1 bar H2 för att stoppa upplösningen. </p> / <p>This licentiate thesis deals with the influence of two inherent properties (fission products and self irradiation) of spent nuclear fuel on the rate of radiation induced fuel matrix (UO2) dissolution. In a future deep repository the spent nuclear fuel will be deposited 500 meters down in the bedrock in a reducing environment. Under these conditions the UO2-matrix itself is one of the protective barriers against release of radionuclides due to its very low solubility. When the fuel comes in contact with water, U(IV) will be oxidized to U(VI) by products from radiolysis of water and the solubility of the fuel matrix will increase significantly.</p><p>Most previous studies have been performed on unirradiated UO2 which differ significantly from spent nuclear fuel. In spent nuclear fuel most of the fission products and neutron activation products are radioactive and therefore the fuel will be irradiated by itself. The effect of ionizing radiation on the reactivity of UO2 has been investigated here. UO2 (powder and fragment of a pellet) has been exposed to irradiation in a 60Co γ-source or in an electron accelerator and then the redox reactivity was studied. The kinetics for oxidation of UO2 by MnO4 - was used as a monitoring reaction. It was shown that the reactivity of UO2 increases when being irradiated for the first time (<20kGy). The effect increases with increasing dose until reaching a maximum value ~1.3 times the reactivity of unirradiated UO2 for dry irradiation. For wet irradiation a dose of 140 kGy increases the reactivity ~2.5 times. This effect appears to be permanent.</p><p> Previous studies have shown that H2O2 is the most important oxidant for spent nuclear fuel dissolution under deep repository conditions. Under H2 atmosphere, as expected in a deep repository, it has been shown that the dissolution rate is slower. This has partly been attributed to the reaction between H2O2 and H2 which is very slow without a catalyst. The catalytic effect of UO2 on this reaction was examined showing that UO2 does not catalyze this reaction.</p><p> Another possible catalyst for this reaction is the ε-particles (noble metal particles containing Mo, Ru, Tc, Pd and Rh) formed by the fission products. Pd is a well known catalyst for reduction by H2. The possible catalytic effect of Pd on the reaction between H2O2 and H2 is examined here. The possible catalytic effect of Pd on the reduction of U(VI) by H2 is also examined, both in aqueous phase and in UO2 pellets containing different amounts of Pd (as a model for spent fuel containing ε-particles).</p><p> It was found that Pd has a catalytic effect on the reaction between H2O2 and H2, the second order rate constant is determined to (2.1±0.1)x10-5 m s-1. Pd also has a catalytic effect on the reduction of U(VI) by H2 both in aqueous solution, rate constant (1.5±0.1)x10-5 m s-1, and in the solid phase, rate constants 4x10-7 m s-1 and 7x10-6 m s-1 for pellets with 1 and 3 % Pd respectively. These values are very close to the diffusion limit for these systems. The catalytic effect in the solid phase shows that the dissolution for 100 year old fuel can be completely inhibited, at 40 bar H2 a noble metal particle content of 10-20 ppm is needed and with 1 % noble metal particle content 0.1 bar H2 is enough to stop the dissolution. </p>

The release of radionuclides is a key process in the safety assessment of a deep geological repository for spent nuclear fuel. A large fraction of the release is assumed to be a consequence of dissolution of the fuel matrix, UO2. In this doctoral thesis, the kinetics and the mechanisms behind oxidative U(IV) dissolution were studied. The eects of solid phase inclusions mimicking the presence of fission products, and solutes mimicking expected groundwater components were also evaluated. Palladium, as a model substance for noble metal particle (fission products) inclusions, was shown to catalyze surface oxidation of U(IV), as well as reduction of U(VI). The second order rate constant for the surface reduction of U(VI) by H2was found to be on the order of 10-6 m s-1 (diusion controlled). Under 40 bar H2, 1 wt.% Pd was sufficient to suppress oxidative U(IV) dissolution in 2mM H2O2 aqueous solution. During g γirradiation under 1 bar H2, 0.1 wt.% Pd were sufficient to completely suppress oxidative dissolution. Under inert conditions, where H2 is only produced radiolytically, complete inhibition is observed for 3 wt.% Pd. The presence of Y2O3 as a model substance for trivalent fission products was found to decrease U(VI) dissolution significantly under inert, as well as reducing conditions. Based on kinetic data, it was shown that pure competition kinetics cannot explain the observed decrease. From experiments using pure oxidants it was shown that Y2O3 doping of UO2 decreases the redox reactivity. In addition, from experiments where hydroxyl radical formation from the catalytic decomposition of H2O2 was monitored, it could be concluded that doping has a minor influence on this process. On the basis of numerical simulations, the H2 concentration necessary to suppressradiolytic H2O2 production was found to increase with an increase in dose rate or HCO-3 concentration. Furthermore, the steady state concentration of H2O2 was found to be inversely proportional to the H2 pressure, and proportional to the square root of the dose rate. Fe2 diers strongly from the total reaction volume, the actual dose rate should not be converted into a homogeneous dose rate in numerical simulations. / QC 20110511

QC 20110608

Radiolabeled compounds, cis-diammine-(1,1-cyclobutanedicarboxylato)-$\sp{\rm 193m}$Pt(II) (carboplatin) and dipyrrolidinedithiocarbamato-$\sp{212}$Pb(II) (Pb(PDC)$\sb2$) were synthesized in microscale quantities. High performance liquid chromatography (HPLC) techniques were employed as both a synthetic tool and mode of product analysis. The specific activities of the purified radiochemicals were in the gigabecquerel per mg range. This was adequate for radiobiological experiments and is several orders of magnitude higher than that required for tracer studies. The radionuclide $\sp{\rm 193m}$Pt with 4.3 day half-life emits numerous low energy Auger electrons by virtue of its 3-step isomeric decay essentially by internal conversion. The yields and energies of the electrons were calculated using Monte Carlo methods. This radionuclide was produced by the $\sp{192}$Pt(n,$\gamma)\sp{\rm 193m}$Pt reaction. Other avenues of production, $\sp{192}$Os($\alpha$,3n)$\sp{\rm 193m}$Pt, were also considered. The $\beta$ emitting $\sp{212}$Pb, which decays to $\alpha$ particle emitting daughters, was isolated from a $\sp{226}$Ra generator. The clonogenic survival of Chinese hamster V79 cells was investigated using both radiolabeled and nonradiolabeled forms of the compounds. The effects of the two types of ionizing radiation (Auger electrons and $\alpha$ particles), kinetics of cellular uptake and retention, and subcellular distribution of these compounds were studied. The dosimetry calculations were performed using the radiation spectra, biokinetics, and Medical Internal Radiation Dose (MIRD) formalism. The mean lethal values of dose (D$\sb{37}$) for the radiolabeled carboplatin and $\sp{212}$Pb(PDC)$\sb2$ were 0.453 grays and 0.85 grays, respectively. The values of relative biological effectiveness (RBE) were estimated to be about 8.8 for radiolabeled carboplatin and 4.6 (2.4 with recoil of the daughter nuclei included) for radiolabeled $\sp{212}$Pb(PDC)$\sb2.$ The results confirm the inadequacy of the current methods of dose calculation (MIRD) and International Commission on Radiation Units and Measurements (ICRU) and point to the potential usefulness of $\sp{\rm 193m}$Pt-carboplatin in chemo-Auger combination therapy of cancer.