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Behavior of nuclear waste elements during hydrothermal alteration of glassy rhyolite in an active geothermal system: Yellowstone National Park, Wyoming

Description: The behavior of a group of nuclear waste elements (U, Th, Sr, Zr, Sb, Cs, Ba, and Sm) during hydrothermal alteration of glassy rhyolite is investigated through detailed geochemical analyses of whole rocks, glass and mineral separates, and thermal waters. Significant mobility of U, Sr, Sb, Cs, and Ba is found, and the role of sorption processes in their observed behavior is identified. Th, Zr, and Sm are relatively immobile, except on a microscopic scale. 9 references, 2 figures, 2 tables.
Date: December 31, 1984
Creator: Sturchio, N.C. & Seitz, M.G.
Partner: UNT Libraries Government Documents Department

United States Transuranium and Uranium Registries. Annual Report, October 1, 1993--September 30, 1994

Description: This report summarizes the salient activities and progress of the United States Transuranium. and Uranium Registries for the period October 1, 1993 through September 30, 1994, along with details of specific programs areas including the National Human Radiobiology Tissue Repository (NHRTR) and tissue radiochemistry analysis project. Responsibility for tissue radioanalysis was transferred from Los Alamos National Laboratory to Washington State University in February 1994. The University of Washington was selected as the Quality Assurance/Quality Control laboratory and a three way intercomparison with them and LANL has been initiated. The results of the initial alpha spectrometry intercomparison showed excellent agreement among the laboratories and are documented in full in the Appendices to the report. The NHRTR serves as the initial point of receipt for samples received from participants in the USTUR program. Samples are weighed, divided, and reweighed, and a portion retained by the NHRTR as backup or for use in other studies. Tissue specimens retained in the NHRTR are maintained frozen at -70 C and include not only those from USTUR registrants but also those from the radium dial painter and thorium worker studies formerly conducted by Argonne National Laboratory. In addition, there are fixed tissues and a large collection of histopathology slides from all the studies, plus about 20,000 individual solutions derived from donated tissues. These tissues and tissue related materials are made available to other investigators for legitimate research purposes. Ratios of the concentration of actinides in various tissues have been used to evaluate the biokinetics, and retention half times of plutonium and americium. Retention half times for plutonium in various soft tissues range from 10-20 y except for the testes for which a retention half time of 58 y was observed. For americium, the retention half time in various soft tissues studied was 2.2-3.5 y.
Date: August 1, 1995
Creator: Kathren, R.L. & Harwick, L.A.
Partner: UNT Libraries Government Documents Department

Completely automated nuclear reactors for long-term operation

Description: The authors discuss new types of nuclear fission reactors optimized for the generation of high-temperature heat for exceedingly safe, economic, and long-duration electricity production in large, long-lived central power stations. These reactors are quite different in design, implementation and operation from conventional light-water-cooled and -moderated reactors (LWRs) currently in widespread use, which were scaled-up from submarine nuclear propulsion reactors. They feature an inexpensive initial fuel loading which lasts the entire 30-year design life of the power-plant. The reactor contains a core comprised of a nuclear ignitor and a nuclear burn-wave propagating region comprised of natural thorium or uranium, a pressure shell for coolant transport purposes, and automatic emergency heat-dumping means to obviate concerns regarding loss-of-coolant accidents during the plant`s operational and post-operational life. These reactors are proposed to be situated in suitable environments at {approximately}100 meter depths underground, and their operation is completely automatic, with no moving parts and no human access during or after its operational lifetime, in order to avoid both error and misuse. The power plant`s heat engine and electrical generator subsystems are located above-ground.
Date: January 1, 1996
Creator: Teller, E.; Ishikawa, M. & Wood, L.
Partner: UNT Libraries Government Documents Department

Solubility experiments for the Nevada Nuclear Waste Storage Investigations Project

Description: In response to the need for experimental data on the solubility of waste elements under conditions that are characteristic of a potential repository at Yucca Mountain, the Nevada Nuclear Waste Storage Investigations project has proposed a series of experiments to measure solubilities. This report outlines the experimental conditions that will be used for these measurements. Water compositions, temperatures, important waste elements, the importance of solids in their control of solubility, and the effect of radiation are discussed. 20 refs.
Date: November 1, 1985
Creator: Kerrisk, J.F.
Partner: UNT Libraries Government Documents Department

Solubility limits on radionuclide dissolution

Description: This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution rates of some elements (Pu, Am, Sn, Th, Zr, Sm) are always limited by solubility. Dissolution rates of other elements (Cs, Tc, Np, Sr, C, I) are never solubility limited; their release would be limited by dissolution of the bulk waste form. Still other elements (U, Cm, Ni, Ra) show solubility-limited dissolution under some conditions. 9 references, 3 tables.
Date: December 31, 1984
Creator: Kerrisk, J.F.
Partner: UNT Libraries Government Documents Department

Lunar prospector measurements of the distribution of incompatible elements gadolinium, samarium and thorium

Description: Lunar Prospector neutron spectrometer (NS) and gamma ray spectrometer (GRS) observations have been used to map out the distribution of incompatible elements on the lunar surface. Specifically, the GRS data provide maps of the distribution of thorium and potassium while the NS data provide information on the distribution of iron and titanium, and the rare earth elements gadolinium and samarium. Using results of analysis of Celementine spectral reflectance (CSR) data, the Fe- and Ti-contributions to the NS data can be removed, leaving primarily rare earth element contributions from Gd and Sm. The Th and K maps correlate with the inferred Gd and Sm maps (r {approximately} 0.93), but there are regions of significant disagreement. One of these is in the KREEP-rich circum-Imbrium ring. No clear explanation has emerged for this disagreement, though Th, K, Gd and Sm have differing degrees of incompatibility. These results clearly are important to discussions of the geochemistry of the Procellarum-Imbrium Th-rich Terrane and the South-Pole-Aitken Terrane.
Date: April 1, 1999
Creator: Elphic, R.C.; Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Maurice, S.; Binder, A.B. et al.
Partner: UNT Libraries Government Documents Department

Delineating the major KREEP-bearing terranes on the moon with global measurements of absolute thorium abundances

Description: The Lunar Prospector (LP) Gamma-Ray Spectrometer (GRS) has been used to map the global composition of thorium on the lunar surface. Previous LP results of relative thorium abundances demonstrated that thorium is highly concentrated in and around the nearside western maria and less so in the South Pole Aitken (SPA) basin. Using new detector modeling results and a larger data set, the authors present here a global map of absolute thorium abundances on a 2{degree} by 2{degree} equal-area pixel scale. Because thorium is a tracer of KREEP-rich material, these data provide fundamental information regarding the locations and importance of terranes that are rich in KREEP bearing materials.
Date: March 1, 1999
Creator: Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Elphic, R.C.; Prettyman, T.H.; Binder, A.B. et al.
Partner: UNT Libraries Government Documents Department

Assessment of the important radionuclides in nuclear waste

Description: The relative importance of the various radionuclides contained in nuclear waste has been assessed by consideration of (1) the quantity of each radionuclide present, (2) the Environmental Protection Agency`s release limits for radionuclides, (3) how retardation processes such as solubility and sorption affect radionuclie transport, and (4) the physical and chemical forms of radionuclides in the waste. Three types of waste were reviewed: spent fuel, high-level waste, and defense high-level waste. Conditions specific to the Nevada Nuclear Waste Storage Investigations project potential site at Yucca Mountain were used to describe radionuclide transport. The actinides Am, Pu, Np, and U were identified as the waste elements for which solubility and sorption data were most urgently needed. Other important waste elements were identified as Sr, Cs, C, Ni, Zr, Tc, Th, Ra, and Sn. Under some conditions, radionuclides of three elements (C, Tc, and I) may have high solubility and negligible sorption. The potential for transport of some waste elements (C and I) in the gas phase must also be evaluated for the Yucca Mountain Site. 12 refs., 17 tabs.
Date: October 1, 1985
Creator: Kerrisk, J.F.
Partner: UNT Libraries Government Documents Department

Fixed capital investments for the uranium soils integrated demonstration soil treatment technologies

Description: The development of a nuclear industry in the United States required mining, milling, and fabricating a large variety of uranium products. One of these products was purified uranium metal which was used in the Savannah River and Hanford Site reactors. Most of this feed material was produced at the United States Department of Energy (DOE) facility formerly called the Feed Materials Production Center at Fernald, Ohio. During operation of this facility, soils became contaminated with uranium from a variety of sources. To address remediation and management of uranium-contaminated soils at sites owned by DOE, the Uranium Soils Integrated Demonstration (USID) Program was formed to evaluate and compare the versatility, efficiency, and economics of various technologies that may be combined into systems designed to characterize and remediate uranium contaminated soils. The USID Program has five major tasks in developing and demonstrating these technologies. Each must be able to (1) characterize the uranium in soil, (2) decontaminate or remove uranium from soil, (3) treat or dispose of resulting waste streams, (4) meet necessary state and federal regulations, and (5) meet performance assessment objectives. The role of the performance assessment objectives is to provide the information necessary to conduct evaluations of the technologies. These performance assessments provide the basis for selecting the optimum system for remediation of large areas contaminated with uranium. One of the performance assessment tasks is to address the economics of full-scale implementation of soil treatment technologies developed by the USID Program. The cost of treating contaminated soil is one of the criteria used in the decision-making process for selecting remedial alternatives.
Date: May 1, 1995
Creator: Douthat, D.M.; Armstrong, A.Q. & Stewart, R.N.
Partner: UNT Libraries Government Documents Department

Solvent extraction study of the thorium nitrate, nitric acid, and tributyl phosphate-dodecane system: density and acidity relationships

Description: A solvent extraction study to determine equilibrium conditions of thorium nitrate-nitric acid with 30% tributyl phosphate in normal dodecane has been completed. Experimental conditions studied were 30 to 60{sup 0}C, 0.05 to 1.5 M Th(NO{sub 3}){sub 4}, and 0.0 to 3.0 M HNO{sub 3}. The extractant concentration was constant at 30% tributyl phosphate. The equilibrium experiments have produced data which demonstrate that thorium nitrate concentration, free acid, and density are related in equilibrium behavior between the aqueous and organic phases from 30 to 60{sup 0}C in the 30% tributyl phosphate-dodecane solvent extraction system. The concentration interactions apply to both the two- and three-phase regions. A linear correlation was observed for the density (D) of the aqueous or organic phase and the concentration of thorium and free acid. The general form of the equation is D = a(C/sub Th/ + bC/sub H/) + c, where a is the slope, b is the constant, c is the intercept, and C/sub Th/ and C/sub H/ are the molar concentrations of thorium and free acid respectively. The relationship of temperature, thorium nitrate, and free acid makes possible the definitions of the boundaries between the two- and three-phase regions. This dependence, in turn, permits operational control or simulation studies of the system within the two-phase region. The data demonstrate the interactions of the components of the Thorex system and can be used to improve the mathematical description of equilibrium in the SEPHIS-Thorex computer program.
Date: May 1, 1980
Creator: Weinberger, A.J.; Marley, J.L. & Costanzo, D.A.
Partner: UNT Libraries Government Documents Department

Dissolution of ORNL HLW sludge and partitioning of the actinides using the TRUEX process

Description: Experiments were conducted to evaluate the transuranium extraction (TRUEX) process for partitioning actinides from actual dissolved high-level radioactive waste (HLW) sludge. Samples of sludge from melton Valley Storage Tank W-25 were rinsed with mild caustic (0.2 M NaOH) to reduce the concentrations of nitrates and fission products associated with the interstitial liquid. In one campaign the rinsed sludge was leached in nitric acid, and about 50% of the dry mass of the sludge was dissolved. The resulting solution contained total metal concentrations of {approximately} 1.8 M with a nitric acid concentration of 2.9 M. In the other campaign the sludge was neutralized with nitric acid to destroy the carbonates, then leached with 2.6 M NaOH for {approximately} 6 h before rinsing with the mild caustic. The sludge was then leached in nitric acid, and about 80% of the sludge dissolved. The resulting solution contained total metal concentrations of {approximately} 0.6 M with a nitric acid concentration of 1.7 M. Chemical analyses of both phases were used to evaluate the process. Evaluation was based on two metrics: the fraction of TRU elements removed from the dissolved sludge and comparison of the results with predictions made with the Generic TRUEX Model (GTM). The fractions of Eu, Pu, Cm, Th and U species removed from aqueous solution in only one extraction stage were > 95% and were close to the values predicted by the GTM. Mercury was also found to be strongly extracted, with a one-stage removal of > 92%. In one test, vanadium appeared to be moderately extracted.
Date: December 1, 1997
Creator: Spencer, B.B.; Egan, B.Z.; Beahm, E.C.; Chase, C.W. & Dillow, T.A.
Partner: UNT Libraries Government Documents Department

Evaluation of alternate extractants to tributyl phosphate. Phase I

Description: Preliminary evaluations have indicated that tri(n-hexyl) phosphate (THP) and tri(2-ethylhexyl) phosphate (TEHP) have some significant advantages over tri(n-butyl) phosphate (TBP) for fuel reprocessing although they also have some disadvantages. The longer alkyl chains in these new extractants decrease their aqueous phase solubility and increase the organic phase solubility of their metal complexes and the metal complexes of their degradation products. Both THP and TEHP extract uranium and plutonium more strongly than TBP; thorium extraction is in the order THP > TBP > TEHP. Tritium extraction is highest with TBP because of slightly higher water extraction. In extractions of thorium, a third liquid phase was formed using TBP at a solvent loading of about 40 g/L of thorium and above. Third-phase formation did not occur with THP or TEHP. The dialkyl phosphoric acid degradation products of THP and TEHP showed a markedly lower tendency to precipitate with thorium than did dibutyl phosphoric acid (HDBP). Chemical stability studies showed TEHP to have much greater stability to acid hydrolysis than TBP and THP, which were about equivalent. No differences were detected in the radiation stability of the three extractants. The phase separation properties of THP and TEHP are inferior to those of TBP in both the nitric acid and sodium carbonate (solvent wash) systems. Phase separation was improved appreciably by using a lower extractant concentration than 1.09 M (equivalent to 30 vol % TBP). Difficulties were encountered with TEHP, however, owing to rapid degradation of its phase separation properties with time of contact with HNO{sub 3}; this problem requires additional study.
Date: April 1, 1981
Creator: Arnold, W.D. & Crouse, D.J.
Partner: UNT Libraries Government Documents Department

Alternate Fuel Cycle Technologies/Thorium Fuel Cycle Technology Programs. Quarterly report for period 1 April--30 June 1978

Description: Voloxidation and dissolution studies: rotary-kiln heat-transfer tests are under way using a small rotary kiln along with the development of a mathematical model to determine kiln-heat-flux profiles necessary to maintain a desired temperature gradient. The erosion/corrosion test for evaluating materials of construction is operational. Fuel from a BWR (Big Rock Point) yielded more fine solid residue on dissolution than in previous tests with PWR fuel. Two additional parametric voloxidation tests with H.B. Robinson fuel compared air vs pure oxygen atmospheres at 550{sup 0}C; overall tritium release and subsequent fuel dissolution were equivalent. Thorium dissolution studies: the dissolution rate of thoria in fluoride-catalyzed 8 to 14 M HNO{sub 3} (100{sup 0}C) was max between 0.04 to 0.06 M HF; at higher fluoride concentrations, ThF{sub 4}.5H{sub 2}O precipitated. The rate of zircaloy dissolution continued to increase with increasing fluoride concentration. Stainless-steel-clad (Th,U)0{sub 2} fuel rods irradiated in the NRX reactor were sheared, voloxidized, and dissolved. {le}10% of the tritium was released during voloxidation in air at 600{sup 0}C. Carbon-14 removal from off-gas and fixation: carbon dioxide removal with Linde 13X molecular sieves to less than 100 ppB was experimentally verified using 300 ppM CO in air. Decontamination factors from 3000 to 7500 were obtained for CO{sub 2} removal in the gas-slurry stirred-tank reactor with CA(OH){sub 2}.or Ba(0H){sub 2}/sup .8H2O./. With Ba(OH){sub 2}.H{sub 2}0{sup 2} in a fixed-bed column, decontamination factors of about 30,000 were obtained.
Date: August 1, 1978
Creator: Vondra, B.L.
Partner: UNT Libraries Government Documents Department

Application of ENDF data to the AVR reactor with highly enriched uranium fuel and thorium feed

Description: Calculations were done applying ENDF data to the German AVR pebble bed reactor at KFA. Several core models were used, and the results obtained with ORNL methods for the multiplication, reaction rates, temperature coefficient of reactivity, and fuel temperature distributions are reported and compared. Only a small difference in multiplication is found for this core in going from ENDF/B-IV to ENDF/B-V cross-section data. The temperature coefficients calculated with the ENDF/B-V are somewhat smaller in magnitude. The worth of control rods was obtained and only a small difference was found with the data, but the calculated results are high compared with experiment. Neutron reaction rates with the key actinides are reported for three-dimensional core calculations.
Date: September 1, 1986
Creator: Vondy, D.R.
Partner: UNT Libraries Government Documents Department

Effects of periodic manual stirring and uranium addition on surrogate plutonium glass processing

Description: Using thorium as a plutonium surrogate, homogeneous glasses have been processed ranging from 15 to 20 elemental weight percent thorium with 0 to 5 elemental weight percent uranium. Homogeneous glasses have been processed at 1,475 C with residence times ranging from 1 to 12 hours. High ramp rates successfully inhibited thorium silicate formation. Residence times of 5 to 7 hours were required for static melts to become homogeneous for glasses containing 15 elemental weight percent thorium. Thorium dissolution rates have been determined for glasses containing 15 elemental weight percent thorium with and without the addition of uranium. When compared to identical glass compositions which were not stirred, stirred melts produced homogeneous vitreous products with an 80 percent reduction in residence time. A 20 elemental weight percent thorium glass was produced at 1,475 C by adding 2 elemental weight percent uranium. Without the addition of uranium, a melt temperature of 1,500 C was required.
Date: September 13, 1996
Creator: Meaker, T.F.
Partner: UNT Libraries Government Documents Department

Evaluation of Codisposal Viability for TH/U Carbide (Fort Saint Vrain HTGR) DOE-Owned Fuel

Description: There are more than 250 forms of US Department of Energy (DOE)-owned spent nuclear fuel (SNF). Due to the variety of the spent nuclear fuel, the National Spent Nuclear Fuel Program has designated nine representative fuel groups for disposal criticality analyses based on fuel matrix, primary fissile isotope, and enrichment. The Fort Saint Vrain reactor (FSVR) SNF has been designated as the representative fuel for the Th/U carbide fuel group. The FSVR SNF consists of small particles (spheres of the order of 0.5-mm diameter) of thorium carbide or thorium and high-enriched uranium carbide mixture, coated with multiple, thin layers of pyrolytic carbon and silicon carbide, which serve as miniature pressure vessels to contain fission products and the U/Th carbide matrix. The coated particles are bound in a carbonized matrix, which forms fuel rods or ''compacts'' that are loaded into large hexagonal graphite prisms. The graphite prisms (or blocks) are the physical forms that are handled in reactor loading and unloading operations, and which will be loaded into the DOE standardized SNF canisters. The results of the analyses performed will be used to develop waste acceptance criteria. The items that are important to criticality control are identified based on the analysis needs and result sensitivities. Prior to acceptance to fuel from the Th/U carbide fuel group for disposal, the important items for the fuel types that are being considered for disposal under the Th/U carbide fuel group must be demonstrated to satisfy the conditions determined in this report.
Date: September 28, 2001
Creator: Radulescu, H.
Partner: UNT Libraries Government Documents Department

Crystal structure of actinide metals at high compression

Description: The crystal structures of some light actinide metals are studied theoretically as a function of applied pressure. The first principles electronic structure theory is formulated in the framework of density functional theory, with the gradient corrected local density approximation of the exchange-correlation functional. The light actinide metals are shown to be well described as itinerant (metallic) f-electron metals and generally, they display a crystal structure which have, in agreement with previous theoretical suggestions, increasing degree of symmetry and closed-packing upon compression. The theoretical calculations agree well with available experimental data. At very high compression, the theory predicts closed-packed structures such as the fcc or the hcp structures or the nearly closed-packed bcc structure for the light actinide metals. A simple canonical band picture is presented to explain in which particular closed-packed form these metals will crystallize at ultra-high pressure.
Date: August 1, 1995
Creator: Fast, L. & Soederlind, P.
Partner: UNT Libraries Government Documents Department

A Review of Thorium Utilization as an option for Advanced Fuel Cycle--Potential Option for Brazil in the Future

Description: Since the beginning of Nuclear Energy Development, Thorium was considered as a potential fuel, mainly due to the potential to produce fissile uranium 233. Several Th/U fuel cycles, using thermal and fast reactors were proposed, such as the Radkwoski once through fuel cycle for PWR and VVER, the thorium fuel cycles for CANDU Reactors, the utilization in Molten Salt Reactors, the utilization of thorium in thermal (AHWR), and fast reactors (FBTR) in India, and more recently in innovative reactors, mainly Accelerator Driven System, in a double strata fuel cycle. All these concepts besides the increase in natural nuclear resources are justified by non proliferation issues (plutonium constrain) and the waste radiological toxicity reduction. The paper intended to summarize these developments, with an emphasis in the Th/U double strata fuel cycle using ADS. Brazil has one of the biggest natural reserves of thorium, estimated in 1.2 millions of tons of ThO{sub 2}, as will be reviewed in this paper, and therefore R&D programs would be of strategically national interest. In fact, in the past there was some projects to utilize Thorium in Reactors, as the ''Instinto/Toruna'' Project, in cooperation with France, to utilize Thorium in Pressurized Heavy Water Reactor, in the mid of sixties to mid of seventies, and the thorium utilization in PWR, in cooperation with German, from 1979-1988. The paper will review these initiatives in Brazil, and will propose to continue in Brazil activities related with Th/U fuel cycle.
Date: October 3, 2004
Creator: Maiorino, J.R. & Carluccio, T.
Partner: UNT Libraries Government Documents Department

RADIOACTIVITY DOSAGE OF ORNAMENTAL GRANITIC ROCKS BASED ON CHEMICAL, MINERALOGICAL AND LITHOLOGICAL DATA

Description: One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite and zircon. Chemical analysis revealed concentrations of uranium of {le} 30ppm, and thorium {le} 130ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for floor tiles in a standard room for samples with total concentration of uranium and thorium greater than 60ppm. On the basis of calculations of {sup 232}Th, {sup 40}K and {sup 226}Ra from Th, K and U analysis, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.
Date: October 3, 2004
Creator: Salas, H.T.; Nalini, H.A. Jr. & Mendes, J.C.
Partner: UNT Libraries Government Documents Department

Design of a boiling water reactor equilibrium core using thorium-uranium fuel

Description: In this paper the design of a Boiling Water Reactor (BWR) equilibrium core using thorium is presented; a heterogeneous blanket-seed core arrangement concept was adopted. The design was developed in three steps: in the first step two different assemblies were designed based on the integrated blanket-seed concept, they are the blanket-dummy assembly and the blanket-seed assembly. The integrated blanketseed concept comes from the fact that the blanket and the seed rods are located in the same assembly, and are burned-out in a once-through cycle. In the second step, a core design was developed to achieve an equilibrium cycle of 365 effective full power days in a standard BWR with a reload of 104 fuel assemblies designed with an average 235U enrichment of 7.5 w/o in the seed sub-lattice. The main operating parameters, like power, linear heat generation rate and void distributions were obtained as well as the shutdown margin. It was observed that the analyzed parameters behave like those obtained in a standard BWR. The shutdown margin design criterion was fulfilled by addition of a burnable poison region in the assembly. In the third step an in-house code was developed to evaluate the thorium equilibrium core under transient conditions. A stability analysis was also performed. Regarding the stability analysis, five operational states were analyzed; four of them define the traditional instability region corner of the power-flow map and the fifth one is the operational state for the full power condition. The frequency and the boiling length were calculated for each operational state. The frequency of the analyzed operational states was similar to that reported for BWRs; these are close to the unstable region that occurs due to the density wave oscillation phenomena in some nuclear power plants. Four transient analyses were also performed: manual SCRAM, recirculation pumps trip, main steam ...
Date: October 6, 2004
Creator: Francois, J-L.; Nunez-Carrera, A.; Espinosa-Paredes, G. & Martin-del-Campo, C.
Partner: UNT Libraries Government Documents Department

Assays and screening of alpha contaminated soils using low-resolution alpha spectroscopy of thick soil samples

Description: A new approach to estimating concentrations of alpha-emitting contaminants (e.g. U, Th, Ra, Pu, Am) in soil samples has been evaluated. The Victoreen Alpha Activity Monitor has been designed to empirically assay soil samples using low-resolution alpha spectroscopy, of thick soil samples. Pre-processing of the soil samples is minimal, involving only drying the soils and milling them to reduce inhomoceneities. Several laboratory tests of the instrument have been conducted. It has been shown that the instrument obeys simple counting statistics with measurement reproducibility improving with the inverse square root of the counting time. Using acquisition times of 1 to 24 hours the instrument Generated alpha assays of eighteen reference and field soil samples which were in good agreement with radiochemical analyses. It was observed that the alpha activity due to a 10pCi/g {sup 239}Pu spike added to a clean soil could be very readily distinguished from the 14pCi/g background activity of the soil. In a mock field screening test of 100 Pu-contaminated soils, the instrument demonstrated screening success rates ranging from 70% (at a screening level of 5pCi/g) to greater than 90% (at a screening level of 30pCi/g).
Date: April 1, 1995
Creator: Meyer, K.E.; Lucas, A.C. & Padovan, S.
Partner: UNT Libraries Government Documents Department

Results of the independent radiological verification survey at 79 Avenue E, Lodi, New Jersey (LJ091V)

Description: Prior to remediation, thorium residues in excess of DOE applicable guidelines were found in the eastern comer of the backyard on property at 79 Avenue B, Lodi, New Jersey. Decontamination, which consisted of excavation and removal of contaminated soil, was performed by subcontractors under the direction of Bechtel National, Inc. The independent radiological verification survey described in this report was performed by the Measurement Applications and Development Group at Oak Ridge National Laboratory to verify that the final remedial action had reduced contamination levels to within authorized limits. The property at 79 Avenue B, Lodi, New Jersey, was thoroughly investigated outdoors for radionuclide residues. Surface gamma exposure rates were below guideline levels and comparable the area. The results of soil radionuclide analysis for all soil concentration measurements were below limits prescribed by DOE applicable guidelines for protection against radiation. Analysis of data contained in the post-remedial action report and results of this independent radiological verification survey by ORNL confirm that all radiological measurements fall below the limits prescribed by DOE guidelines established for this site. The property at 79 Avenue B successfully meets the DOE remedial action objectives.
Date: September 1, 1996
Creator: Rodriguez, R.E. & Uziel, M.S.
Partner: UNT Libraries Government Documents Department