Energy Technology Data Exchange (ETDEWEB)

Isothermal reaction experiments were performed in the temperature range of 1000 - 1300 C in order to determine the chemical interactions between Zircaloy-4 fuel rod cladding and Inconel-718 spacer grids of Pressurized Water Reactors (PWR) under severe accident conditions. It was not possible to apply even higher temperatures since fast and complete liquefaction of the components occurred as a result of eutectic interactions during heatup. The liquid reaction products formed enhance and accelerate the degradation of the material couples and the fuel elements, respectively. Only small amounts of Inconel are necessary to liquefy large amounts of Zircaloy. Thin oxide layers on the Zircaloy surface delay the beginning of the chemical interactions with Inconel but cannot prevent them. In this work the reaction kinetics have been determined for the system: as-received and pre-oxidized ...

International Nuclear Information System (INIS)

Zircaloy-2 and Zircaloy-4 tubing materials were irradiated with 1 MeV proton at 350 degrees C to doses of 0.01, 0.1, and 1 dpa respectively. Both microstructure examination and nodular corrosion test (500 degrees C, 1500 psi steam) were performed in order to understand the relationship between the microstructural evolution and the corrosion resistance of these alloys under irradiation. Neutron-irradiated Zircaloy-2 specimens which were obtained from a failed BWR fuel rod cladding were also studied. Specimens of three different neutron fluences were investigated; namely, 2.6x10"2"4, 3.2x10"2"5, 3.8x10"2"5, (E_n#>=#1MeV). The results indicated that the higher the irradiation dose the better the nodular corrosion resistance of both Zircaloy-2 and Zircaloy-4. It is concluded that irradiation-induced precipitate dissolution and irradiation-enhanced diffusion may increase the solute ...

International Nuclear Information System (INIS)

A study of stress corrosion cracking susceptibility of Zircaloy-4 in chloride-containing aqueous methanolic media is presented. The influence of water content is investigated in the 5-100 vol. % water range. The dependence of stress corrosion cracking on potential is evidenced. A close correlation is established with pitting susceptibility determined by a statistical analysis of induction times. A correlation with the repassivation potential is observed in the water-rich solutions. In the low water content solutions, two repassivation curves are determined according to the experimental technique. Pit morphology and fractography show a transition from aqueous to organic media. (author).

International Nuclear Information System (INIS)

This work is concerned with the development and application of ion implantation techniques for improving the corrosion resistance of zircaloy-4. The corrosion resistance in nitrogen implanted zircaloy-4 under a 120 keV nitrogen ion beam at an ion dose of 3 x 10"1"7 cm"-"2 depends on the implantation temperature. The characteristics of surface oxidation and corrosion resistance were analyzed with the change of implantation temperature. It is shown that as implantation temperature rises from 100 to 724 C, the colour of specimen surface changes from its original colour to light yellow at 100 C, golden at 175 C, pink at 300 C, blue at 440 C and dark blue at 550 C. As the implantation temperature goes above 640 C, the colour of surface changes to light black, and the surface becomes a little rough. The corrosion resistance of zircaloy-4 implanted with nitrogen is ...

Energy Technology Data Exchange (ETDEWEB)

The experimental effect investigation programme on Zircaloy-4/air oxidation was pursued and expanded to isothermal specimen exposure and the comparison of the oxidation between the atmospheres Ar/O{sub 2} and air. In close connection with the EC project OPSA, which is meanwhile terminated, the investigation concerned specimen exposure in a thermobalance to flowing atmospheres, namely dry Ar/O{sub 2} of composition 80/20 or synthetic air, respectively. As test parameters the linear heat-up rate was varied in the range 5 to 40 K/min and the ramp or holding temperature between 800 and 1500 C. Mass increase and reaction rate were continuously recorded or evaluated in temperature/time dependence. The oxide scale growth was found to be accompanied by colour changes, crack formation and spalling of layers, as well as by dimensional substrate growth, which are the reasons for the observed kinetic results. The microstructural investigation confirms ...

International Nuclear Information System (INIS)

An important application of metal hydrides is as a moderator material in nuclear reactors. The fundamental properties of hydrides are illustrated and an impression given of the current research into hydrogen in transition metals. Phase diagrams, magnetic properties, temperature dependence of the diffusion coefficient, energy level schemes and superconductivity are considered. (C.F.).

International Nuclear Information System (INIS)

The plasma cladding waveguide, which is a cylindrical dielectric core surrounded by a plasma cladding, is developed, and the guided modes and their characteristics of this waveguide are displayed through the present detailed theoretical research. The conditions of the single mode existing in the plasma cladding waveguide have been given, and the defined forbidden gap of frequency is discussed. It is found that the usage characteristics of the plasma cladding waveguide vary strongly with plasma frequency, and changing the plasma parameters can control the propagation mode. This paper focuses on exhibiting the basic characteristics and the potential applications of this new type of waveguide.

International Nuclear Information System (INIS)

Alloying elements such as Fe and Cr are generally considered to be effective even in small quantities for corrosion resistance of Zircaloy-4. The maximum total solubility of Fe + Cr in a Zr-Sn matrix has been reported to be very low. Therefore, most of these elements are observed in the form of ternary Zr-Fe-Cr-type precipitates. To clarify the effects of precipitates on corrosion property, Zr-1.3 Sn-(Fe,Cr) alloys containing Fe + Cr from 45 up to 180 ppm (the Fe to Cr ratio is about 2) were melted from pure zirconium (X-bar Zr and EB-Zr) and pure alloying elements. They were subjected to corrosion testing in 633 K water and microstructural analysis. It was found that precipitate-free materials showed much larger weight gains than precipitate-containing materials even at the same alloy compositions. Subsequently, a corrosion test on the precipitate-free material galvanically coupled with a noble intermetallic compound of ...

International Nuclear Information System (INIS)

The method of programmed thermodesorption has been used to study the forms of hydrogen adsorption in ZrNiHsub(x) hydride. It is shown that high concentration of the hydrogen, which extracted from hydride in the temperature range of 240-260 deg C results in appearance of ''reverse'' peak. Charge of hydride adsorption properties during its oxidation-reduction treatment is studied. Comparison with spectra of hydrogen thermodesorption from the surface of Ni/ZrO_2 deposited catalyst and zirconium oxide is carried out.

International Nuclear Information System (INIS)

Approximately 8% of the spent nuclear fuel owned by the US Department of Energy is clad with aluminum alloys. The spent fuel must be either reprocessed or temporarily stored in wet or dry storage systems until a decision is made on final disposition in a repository. There are corrosion issues associated with the aluminum cladding regardless of the disposition pathway selected. This paper discusses those issues and provides data and analysis to demonstrate that control of corrosion induced degradation in aluminum clad spent fuels can be achieved through relatively simple engineering practices.

International Nuclear Information System (INIS)

In the present work the hydrogen desorption properties of nanostructured magnesium hydride (MgH2) synthesized by controlled reactive mechanical milling (CRMM) of elemental Mg powder under hydrogen are investigated. A profound effect of the particle size of synthesized MgH2 hydride on its hydrogen desorption characteristics measured by differential scanning calorimetery (DSC) has been found. All synthesized MgH2 powders are characterized by a double hydrogen desorption peak. Furthermore, below a certain threshold particle size the DSC desorption temperature of the peak doublet starts decreasing rapidly with decreasing of the mean hydride powder particle size (expressed as equivalent circle diameter-ECD). In contrast, the nanograin (crystallite) size of MgH2 does not seem to have apparent effect on the DSC desorption temperature. It is also observed that for powder particles smaller than some threshold value, X-ray ...

International Nuclear Information System (INIS)

Axial offset anomaly (AOA) is caused by the deposition of crud on the fuel cladding of a PWR. When significant levels of crud build up on the cladding, boron can accumulate in the pores of the crud as a concentrated solution or solid phase, and cause the flux depression. Numerous studies have been conducted on the primary water chemistry to reduce the amount of crud in the primary circuit to avoid radioactivity buildup and unexpected power transition in the plant. However, experiments on the crud are restricted in the laboratory because the crud is a highly radioactive material. The objective of this study is to develop a test method for simulating the deposition of crud in a nuclear power plant

CERN Document Server

The process of radiation induced electron capture by protons or deuterons producing new ultra low momentum neutrons and neutrinos may be theoretically described within the standard field theoretical model of electroweak interactions. For protons or deuterons in the neighborhoods of surfaces of condensed matter metallic hydride cathodes, such conversions are determined in part by the collective plasma modes of the participating charged particles, e.g. electrons and protons. The radiation energy required for such low energy nuclear reactions may be supplied by the applied voltage required to push a strong charged current across a metallic hydride surface employed as a cathode within a chemical cell. The electroweak rates of the resulting ultra low momentum neutron production are computed from these considerations.

Energy Technology Data Exchange (ETDEWEB)

An Fe-19Cr-8Al-0.5Hf alloy has been roll bonded to Alloy 800 to form a protective clad material suitable for use in coal conversion atmospheres. The commercial producibility of both the Fe-19Cr-8Al-0.5Hf alloy and the clad composite has been demonstrated. The clad composite has been shown to exhibit resistance to sulfidation in high sulfur, coal gasification atmospheres low Btu for 2000 hrs at 1800/sup 0/F (1255K). The FeCrAlHf alloy must be preoxidized in the absence of sulfur to form fully protective alumina scales on all surfaces. Useful life of the composite at temperatures of 1400 to 2000/sup 0/F (1033 to 1366K) is governed by reactions at the FeCrAlHf clad alloy 800 interface. The rate of interdiffusion decreases with increasing Ni content and a high Ni alloy such as RA333 appears to be a better substrate than Alloy 800 for a FeCrAlHf composite. The mechanical properties of the ...

Energy Technology Data Exchange (ETDEWEB)

Combining in situ Rutherford backscattering and electrical transport measurements on low-temperature hydrogen-implanted amorphous Pd/sub 80/Si/sub 20/ films, we have studied the correlation between the hydrogen content and the resistivity.

International Nuclear Information System (INIS)

In the presence of hydroxyl anion, both formaldehyde and glyoxal are known to undergo rearrangements involving intermolecular and intramolecular hydride transfer (the Cannizzaro and Benzilic acid rearrangements respectively). The authors report ab initio SCF-MO calculations of the transition state geometries, the activation barriers, and the hydrogen isotope effects for these two reactions. The structure of the transition state for the rection involving formaldehyde is usually basis set dependent, becoming more linear and symmetrical as the basis set size increases. In contrast, the analogous transition state for the glyoxal reaction involves a highly non-linear hydride transfer. They find the isotope effects to be quite low for the Cannizzaro reaction, and significantly larger for the non-linear benzilic acid rection, in apparent contradiction to Westheimer's suggestion the isotope effects reach a maximum for linear hydrogen transfers. Since ...

Energy Technology Data Exchange (ETDEWEB)

A prototype hydride storage bed, using LaNi{sub 4.25}Al{sub 0.75} as the storage material, was fitted with strain gages to measure strains occurring in the stainless steel bed vessel caused by expansion of the storage powder upon uptake of hydrogen. The strain remained low in the bed as hydrogen was added, up to a bed loading of about 0.5 hydrogen to metal atom ratio (H/M). The strain then increased with increasing hydrogen loading ({approximately} 0.8 H/M). Different locations exhibited greatly different levels of maximum strain. In no case was the design stress of the vessel exceeded.

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of cladding technology development under the Coal-Fired Combined Cycle DOE Project. Clad Alloy Development, involved the selection, fabrication and burner rig evaluation of advanced clad alloy composition diffusion-bonded to IN-738. Testing was conducted for up to 5800 hours at 1600/sup 0/F in a simulated PFB environment. Metallographic evaluation showed Co-base cladding alloys PFB-5PM and PFB-6PM (aluminided) and Fe-base alloy GE-2541 to be the most corrosion resistant. The formability and fabricability of sheet material was significantly improved for these alloys by utilizing powder metallurgy techniques. Clad Process Development encompassed processing activities to evaluate sheet alloy formability, bucket surface preparation techniques, platform clad forming, and the activated diffusion bonding (ADB) of corrosion resistant ...

Wastenet

... The structure comprises piled foundations supporting a steel frame, and is clad in both masonry and rainscreen cladding systems. The hotel is adjacent to the recently redeveloped bus station in the centre of Norwich. Related Services Structural Design Go View all Services Find Projects Sector All Sectors Buildings & Infrastructure Environment Natural Resources Transportation Sub Sector All Sub-Sectors Country All Countries Angola Antigua and Barbuda Argentina ...

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) features a three-loop, sodium-cooled 400 MWt mixed oxide fueled reactor designed for the irradiation testing of fuels and materials for use in liquid metal cooled fast reactors. To establish the ultimate capability of a particular fuel design and thereby generate information that will lead to improvements, many of the fuel irradiations are continued until a loss of cladding integrity (failure) occurs. When the cladding fails, fission gas escapes from the fuel pin and enters the reactor cover gas system. If the cladding failure permits the primary sodium to come in contact with the fuel, recoil fission products can enter the sodium. The presence of recoil fission products in the sodium can be detected by monitoring for the presence of delayed neutrons in the coolant. It is the present philosophy to not operate FFTF when a failure has occurred that permits fission fragments to enter the ...

Energy Technology Data Exchange (ETDEWEB)

The influence of radiation on the corrosion of the fuel claddings in a Light Water Reactor (LWR) has been the subject of many investigations, and different aspects of the overall phenomena have been studied by different techniques. Analysis of the evolution of Secondary-Phase Particles (SPPs) for different periods of immersion of the cladding in the reactor enables the rate of corrosion to the structure of the material to be correlated. In the case of Zircaloy-2 in a Boiling Water Reactor (BWR), SPPs are dissolved under irradiation, and their dissolution affects the rate of oxidation and other correlated phenomena. In recent studies, the Zircaloy-2 in claddings loaded in the Leibstadt BWR are analysed after one, three and five cycles. Results are presented, and give an account of the changes which occurred in the materials under irradiation. (authors)

Energy Technology Data Exchange (ETDEWEB)

A method and an instrument for determining the total water content in a hydrocarbon fuel using an indicator composition, which includes calcium hydride and phenolphthaleyn, are developed. The essence of the method is fixing the presence of water with its interaction with the calcium hydride and subsequent indication of the formed Ca(OH)2 using the phenolphthallen. To make the indicator composition, a hygroscopic cotton, prewashed by rectified alcohol and dried for 30 minutes at 105 degrees, is impregnated by a 1 percent alcohol solution of phenolphthaleyn and is dried in the same conditions. Then the cotton is processed by a powder form calcium hydride (a layer thickness of 0.1 to 0.2 millimeters, and a granule size of less than or equal to 80 micromters). The indicator composition is placed in a glass tube (a diameter of 4 to 7 millimeters and a length of 80 to 100 millimeters), whose ends are sealed or filled with ...

Energy Technology Data Exchange (ETDEWEB)

The storage of aluminum-clad fuel and target materials in the L-Disassembly Basin at the Savannah River Site for more than 5 years has resulted in extensive pitting corrosion of these materials. In many cases the pitting corrosion of the aluminum clad has penetrated in the uranium metal core, resulting in the release of plutonium, uranium, cesium-137, and other fission product activity to the basin water. In an effort to characterize the extent of corrosion of the Mark 31A target slugs, two unirradiated slug assemblies were removed from basin storage and sent to the Savannah River Technology Center for evaluation. This paper presents the results of the metallography and photographic documentation of this evaluation. The metallography confirmed that pitting depths varied, with the deepest pit found to be about 0.12 inches (3.05 nun). Less than 2% of the aluminum cladding was found to be breached resulting in less than 5% of ...

Energy Technology Data Exchange (ETDEWEB)

The characterization data obtained to date are described for Approved Testing Material 104 (ATM-104), which is spent fuel from Assembly DO47 of the Calvert Cliffs Nuclear Power Plant (Unit 1), a pressurized-water reactor. This report is one in a series being prepared by the Materials Characterization Center at Pacific Northwest Laboratory (PNL) on spent fuel ATMs. The ATMs are receiving extensive examinations to provide a source of well-characterized spent fuel for testing in the US Department of Energy Office of Civilian Radioactive Waste Management (OCRWM) Program. ATM-104 consists of 128 full-length irradiated fuel rods with rod-average burnups of about 42 MWd/kgM and expected fission gas release of about 1%. A variety of analyses were performed to investigate cladding characteristics, radionuclide inventory, and redistribution of fission products. Characterization data include (1) fabricated fuel design, irradiation history, and subsequent storage and handling ...

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of analysis of selected data from the NRU test series dealing with heatup and reflood heat transfer during postulated PWR LOCA conditions. These tests used nuclear fuel rods and some considered clad ballooning and rupture. Also included was an electrically-heated rod ballooning test, REBEKA-6. The COBRA-TF computer program, renamed PYTHONS, was modified and used for the analytical tool. Modifications included provisions for fuel rod gas flow and pressure, creep deformation and rupture, channel blockage, and blockage heat transfer. Calculated clad temperatures for NRU unpressurized rods show quite good agreement with experimental data. The calculated amount and axial extent of clad ballooning for pressurized rods agrees reasonably well with post-test examinations of the NRU bundles. Time to failure was underpredicted in the MT-3 test as a result of the high strength of NRU ...

International Nuclear Information System (INIS)

The decontamination factor is studied as a function of laser fluence for three kinds of clad surfaces viz., plain zircaloy, autoclaved zircaloy and SS with cesium as the test contamination. It has been found that the decontamination factor exhibits a maximal behaviour with the laser fluence and its maximum value occurs at different laser fluences in the three cases. The maximal behaviour is attributed to reduced coupling of energy from the laser beam to the substrate due to the initiation of surface-assisted optical breakdown. The results obtained in the experiment carried out in helium environment qualitatively support this explanation (author)

International Nuclear Information System (INIS)

Electronic structure, volume optimization, bulk moduli, elastic constants, and frequencies of the transversal optical vibrations in LiH, NaH, KH, RbH, and CsH are calculated using the full potential augmented plane wave method, extended with local orbitals, and the full potential linearized augmented plane wave method. The obtained results show some common features in the electronic structure of these compounds, but also clear differences, which cannot be explained using simple empirical trends. The differences are particularly prominent in the electronic distributions and interactions in various crystallographic planes. In the light of these findings we have elaborated some selected experimental results and discussed several theoretical approaches frequently used for the description of various alkali hydride properties.

Energy Technology Data Exchange (ETDEWEB)

In order to obtain highly reliable InGaP/InGaAlP inner stripe (IS) lasers, the authors have clarified the relation between the maximum CW operation temperature and other laser characteristics, such as the pulsed threshold current, characteristic temperature, series resistance, and thermal resistance. The Al composition of the cladding layer, the carrier concentration of the p-cladding layer, and the thicknesses of the active layer and cladding layer have been optimized. It was found that an Al composition of 0.7 was the most suitable for the cladding layer, and the optimized carrier concentration was 4 x 10/sup 17/ cm/sup -3/. A maximum temperature of 90/sup 0/C was obtained for a 0.1 /mu/m active layer thickness and a 0.6 /mu/m cladding layer thickness. This is the highest value for InGaP/InGaAlP IS lasers, to our knowledge. In the case of a 0.06 /mu/m active layer thickness and a ...

Energy Technology Data Exchange (ETDEWEB)

Using commercial AZ31 magnesium alloy sheets, we produced a foamable preform sheet containing titanium hydride (TiH{sub 2}) powder through diffusion-bonding and hot-rolling of four cycles. Heating the preform sheets in Ar atmosphere, we obtained closed-cell magnesium alloy foams with various porosities. The foamed specimen at 883 K showed the maximum porosities of 77%. (orig.)

International Nuclear Information System (INIS)

Cyclic strength of #alpha#+#beta#-titanium alloy BT3-1 is studied under load frequencies of 33 and 300 Hz. The increase in the cyclic strength with growing frequency is caused by formation of FCC interphase layers of titanium hydrides. Their formation is one of possible ways of raising the fatigue strength of titanium alloys. Peculiarities of FCC interlayer formation in #alpha#+#beta# phases under loading frequency variation are revealed.

Energy Technology Data Exchange (ETDEWEB)

Secondary ion mass spectrometry (SIMS) has been used to investigate changes that occur in an advanced Ir-0.3W alloy during high temperature aging. This alloy is used to clad /sup 238/PuO/sub 2/ heat sources used in thermoelectric generators for deep space reconnaissance satellites. Long-term direct contact with PuO/sub 2/ at 1400/sup 0/C leads to physical and chemical changes within the cladding alloy that affect its metallurgical properties. SIMS was used to show that Cr, Fe, Ni, and in some cases O, diffuse from the PuO/sub 2/ into the alloy. Thorium and aluminum diffuse out of the alloy in these same regions. This SIMS study suggests that inward O diffusion and subsequent formation of ThO/sub 2/ on grain boundaries may stabilize the alloy against enhanced grain growth.

Energy Technology Data Exchange (ETDEWEB)

The characterization data obtained to date are described for Approved Testing Material (ATM)-106 spent fuel from Assembly BT03 of pressurized-water reactor Calvert Cliffs No. 1. This report is one in a series being prepared by the Materials Characterization Center at Pacific Northwest Laboratory on spent fuel ATMs. The ATMs are receiving extensive examinations to provide a source of well- characterized spent fuel for testing in the US Department of Energy Office of Civilian Radioactive Waste Management (OCWRM) program. ATM-106 consists of 20 full-length irradiated fuel rods with rod-average burnups of about 3700 GJ/kgM (43 MWd/kgM) and expected fission gas release of /approximately/10%. Characterization data include (1) as-fabricated fuel design, irradiation history, and subsequent storage and handling; (2) isotopic gamma scans; (3) fission gas analyses; (4) ceramography of the fuel and metallography of the cladding; (5) calculated nuclide inventories and ...

Energy Technology Data Exchange (ETDEWEB)

The characterization data obtained to data are described for Approved Testing Material 105 (ATM-105), which is spent fuel from Bundles CZ346 and CZ348 of the Cooper Nuclear Power Plant, a boiling-water reactor. This report is one in a series being prepared by the Materials Characterization Center at Pacific Northwest Laboratory (PNL) on spent fuel ATMs. The ATMs are receiving extensive examinations to provide a source of well-characterized spent fuel for testing in the US Department of Energy Office of Civilian Radioactive Waste Management (OCRWM) Program. ATM-105 consists of 88 full-length irradiated fuel rods with rod-average burnups of about 2400 GJ/kgM (28 MWd/kgM) and expected fission gas release of about 1%. Characterization data include (1) descriptions of as-fabricated fuel design, irradiation history, and subsequent storage and handling; (2) isotopic gamma scans; (3) fission gas analyses; (4) ceramography of the fuel and metallography of the cladding; (5) ...

International Nuclear Information System (INIS)

A series of six transient tests was performed on FFTF irradiated fuel pins to demonstrate their transient performance capability. The tests were performed in the TREAT reactor using sodium loops and instrumented test trains. The TEMECH computer code was used to design overpower transients which would simulate FFTF fuel pin thermal conditions during slow and fast unprotected transients. Some tests were run to substantial overpower levels but terminated prior to fuel pin failure, while other tests were intentionally extended to fuel failure to establish failure thresholds and characteristics. Post-test examination data provided significant cladding strain and fuel melting information used for performance code calibration and validation. These data showed that cladding damage caused by fuel melting is related to the steady state condition of the fuel.

International Nuclear Information System (INIS)

The LWR fuel performance analysis computer code, FRAPCON-1, are evaluated to investigate the performance of CANDU fuel elements loaded in Wolsung-1 reactor. The FRAPCON-1 models of neutron flux depression in fuel and of fuel-to-cladding heat transfer are modified, and the validity of fission gas release model for CANDU fuel is evaluated. And the heavy water properties are provided in calculating the heat transfer coefficient between cladding and coolant. By using the modified code, FRAPCON-1-CSK, the sensitivity studies are carried out for Wolsung-1 fuel element design parameters. The performance analysis is also performed for Wolsung-1 fuel elements. The calculated results are discussed in terms of LWR fuel design criteria because of unavailability of CANDU fuel design criteria. (Author).

Energy Technology Data Exchange (ETDEWEB)

Femaxi-iv is a computer code for the analysis of thermal and mechanical behavior of light water reactor fuel rods during steady-state and transient conditions. The main purpose of femaxi-iv is to calculate the stress and strain distributions in the fuel and cladding due to the pellet-cladding mechanical interaction, and the fission gas release rate during operations, especially power transients. The capability of femaxi-iv was extensively tested with a number of experimental results obtained in some international fuel irradiation programs. This paper provides a general description of the various models involved in femaxi-iv and some results of applications on the experimental data. ((orig.))

Energy Technology Data Exchange (ETDEWEB)

In this paper nickel acetate catalyzed sodium borohydride cartridges have been prepared and hydrolyzed with water for hydrogen production. Two technological solutions have been tested to increase the overall hydrogen yield, namely a porous water diffuser and a hydrophobic membrane. The first was used to improve water diffusion inside the hydride while the second to confine water inside the cartridge. The generated hydrogen flow showed a very reproducible behavior. Hydrogen promptly evolved just after water was pumped into the cartridge. After some initial peaks, a constant hydrogen flow has been recorded for the whole reaction time. The constant flow was related to the presence of the porous diffuser. The use of a hydrophobic membrane to confine the water inside the cartridge allowed to increase the overall hydrogen yield: about 6 water molecules per mol of hydride were required to complete the reaction. The reaction product was identified by ...

Science.gov (United States)

Proposed future space-based beam weapons systems will most probably require an intense neutral particle beam for effective operation across geomagnetic field lines. Such neutral beams can most efficiently be obtained by stripping excess electrons from negative ion beams. The objective of this work is to study the process of dissociative attachment of electrons. Specifically, to measure the cross sections for polar dissociation and dissociative attachment for production of H(-). It is suspected that these dissociative attachment cross sections for the production of H(-) from alkali hydrides are large. The insight gained from this study will be extremely helpful in the fabrication of high current density H(-) beam sources for use in the production of intense neutral hydrogen beams. A selection of alkali hydride molecules will be investigated in order to determine the largest cross sections for the production of H(-) by electron impact. The ...

International Nuclear Information System (INIS)

Ti-15Mo-2.7Nb-3Al-0.2Si (Timetal-21S), a metastable #beta#-titanium alloy, is a candidate material for titanium matrix composite structures in hydrogen-fueled hypersonic planes because of its excellent formability and adequate mechanical properties in the 500--800 C temperature range. The alloy is strengthened through the precipitation of fine #alpha# particles in the #beta# matrix. The mechanical properties and microstructures are controlled by a solutionizing/aging heat treatment. A major concern in using titanium alloys in hydrogen service is the embrittlement caused by the precipitation of hydrides. It is believed that the large solubility of hydrogen in the #beta#-phase would preclude the precipitation of hydrides in Beta titanium alloys, especially at low hydrogen pressures. However, depending on the hydrogen content, a shift in the ductile/brittle transition temperatures to levels much higher than room temperature has been reported for ...

International Nuclear Information System (INIS)

Some results on mechanical property study of copper and titanium subjected to impact load and next to neutron irradiation are presented. It was shown that shock wave influence involves a substantial shape change of the stress-strain diagram and of respective mechanical characteristics. Yield- and ultimate strength were substantially increased, as well as hardness with a considerable drop of plasticity. Also a heat stability of copper and titanium specimens was studied after being treated with shock-waves and neutron radiation. Results are given of electron microscope study of titanium structure sfter explosion hardening, which caused decomposition of hydride segregations in titanium and increased dislocation density.

Energy Technology Data Exchange (ETDEWEB)

We decided to investigate first the interaction of hydrogen with the 4d transition-metal series, with the first element being hcp Y. Because of the recent development of soft pseudopotentials, we chose to use the plane wave basis set to carry out the calculation. Since problems had been associated with the slow convergence in transition metals, we first tested the computational methods by studying the structural properties of Y; results were encouraging. We started the calculation of YH{sub x} with hydrogen occupying different interstitial sites.

International Nuclear Information System (INIS)

This paper present the results of a series of calculations made to determine the "2"3"8Pu production potential of several advanced target assembly designs in the Fast Flux Test Facility (FFTF). These calculations show that by using advanced target designs the intimately mix the "2"3"7Np target material with an yttrium hydride moderator, the FFTF has the potential of producing up to 30 kg of high-quality "2"3"8Pu per year.

Energy Technology Data Exchange (ETDEWEB)

This report for the Swiss Federal Office of Energy (SFOE) presents the overview reports made by SFOE Heads of Program on work done in 2007. Projects reported on in the natural gas-fired fuel cell area include the EU-project REAL-SFOC, the long-term testing of anode-supported SOFC stacks, intermediate-temperature fuel cells based on proton conducting electrolytes, the interdisciplinary ONEBAT project and lifetime-enhancement of SOFC stacks for CHP applications. In the polymer-electrolyte fuel cell (PEFC) area, projects concerning proton-conducting polymer membranes, factors limiting the lifetime of fuel cell membranes, a new highly active oxygen reduction electrode for PEM fuel cell and zinc/air battery applications, the enhancement of PEFC durability and reliability, model-based investigation of PEFC performance, and local gas analysis of PE fuel cells are briefly reported on. Long-term research activities in the hydrogen technology area reported on include those concerning the ...

Energy Technology Data Exchange (ETDEWEB)

The method of production of xAl{sub 2}O{sub 3}-yTiO{sub 2} compositions provides for the depth distribution of coating components and specifies its mechanical properties. In case of the composition obtained by cladding, titanium is mainly concentrated at the substrate. In case of mechanical mixture or composition obtained by sintering the oxides, the depth distribution of coating components is random.

International Nuclear Information System (INIS)

This paper presents the results obtained in the gamma scanning of two fuel pins from the bent subassembly of the fast breeder test reactor (FBTR) using a segmented gamma scanning system employing segment correlation developed for the assay of glove box solid waste. In addition to the actinide profiles, the paper also discusses the fission products and clad activation product profiles and tries to correlate the experimental values of the latter with computed values. (author). 4 refs., 1 fig., 1 tab.

International Nuclear Information System (INIS)

The structure and properties of composite powder coatings on the base of titanium carbide are studied. It is shown the electron-beam welding deposition of powders on the base of nickel and titanium carbide allows to produce of high-quality wear-resistant coatings which superior in density and hardness compared with sputtered ones. Changes of hardening phase volume percentage as well as composition of metal matrix make possible to control coatings hardness

Energy Technology Data Exchange (ETDEWEB)

The US National Energy Policy of 2001 advocated the development of advanced fuel and fuel cycle technologies that are cleaner, more efficient, less waste-intensive, and more proliferation resistant. The need for advanced fuel development is emphasized in on-going DOE-supported programs, e.g., Global Nuclear Energy Initiative (GNEI), Advanced Fuel Cycle Initiative (AFCI), and GEN-IV Technology Development. The Directorates of Energy & Environment (E&E) and Chemistry & Material Sciences (C&MS) at Lawrence Livermore National Laboratory (LLNL) are interested in advanced fuel research and manufacturing using its multi-disciplinary capability and facilities to support a design concept of a small, secure, transportable, and autonomous reactor (SSTAR). The E&E and C&MS Directorates co-sponsored this Laboratory Directed Research & Development (LDRD) Project on Mono-Uranium Nitride Fuel Development for SSTAR and Space Applications. In fact, three out ...

International Nuclear Information System (INIS)

The RESF is utilized for storage of spent fuel under emergency conditions as well as for testing of FM heads. It receives cooling supply from the PHT Pressurizing pumps and after removal of decay heat from the spent fuel it goes to the D2O Storage Tank. The geometry of the RESF system is such that it can not sustain the thermosyphon loop during SBO, due to high frictional forces. To achieve the sustained thermosyphon, modifications in the design were suggested viz., removal of the steam trap and the relief valve above it and replacement by a solenoid valve (SV-16). In the event of SBO, SV-16 will open on 'RESF channel temperature high' signal and connect to FT D2O tank. The tank, being at atmospheric pressure and at lower elevation, will provide higher cooling flow rate through the RESF channel. D2O is periodically removed from the FT D2O tank by operating a Class-II pump intermittently. The analysis was done for the modified RESF system configuration to estimate the flow rate through ...

Science.gov (United States)

A high power AlGaInP single quantum well graded index separate confinement heterostructure. It comprises a substrate and a multiplicity of layers deposited thereon comprising a single Ga{sub x}In{sub x}P quantum well where x has a value from about 0.4 to about 0.6; multiple graded index regions on both sides of the quantum well and cladding layers adjacent to each graded region of the well, the graded region comprising Al{sub y}(Ga{sub 1{minus}y}){sub 0.5}In{sub 0.5}P quaternary alloy; wherein the value of y in the graded region varies from about 0.2 at the quantum well/graded region interface to up to about 0.6 for the cladding layers/graded index regions; the heterostructure having a low broad area threshold current with pulsed thresholds in the range from about 1 to about 2 Amps/cm{sup 2} and a differential efficiency of from about 20 to about 60 percent.

British Library Electronic Table of Contents (United Kingdom)

Laser consolidation (LC) developed by National Research Council???s Industrial Materials Institute (NRC-IMI-London) since mid-1990s, is a laser cladding based rapid manufacturing and material additive process that could fabricate a ???net-shape??? functional metallic shape through a ???layer-upon-layer??? deposition directly from a computer aided design model without using molds or dies. In order to evaluate the LC processability of different materials, some representative nickel-based superalloys (IN-625, IN-718, IN-738, and Waspaloy), stainless steels (austenitic SS316L and martensitic SS420), and lightweight alloys (Ti???6Al???4V titanium alloy and Al-4047 aluminum alloy) have been investigated. Like other laser cladding based processes, due to process-induced rapid directional solidifi...

Energy Technology Data Exchange (ETDEWEB)

JAERI has been performing transient core thermal-hydraulic test program. In the program, authors performed BWR/ABWR DBE simulation tests with a test facility, which can simulate BWR/ABWR transients. The test facility has a 4 x 4 bundle core simulator with 15-rod heaters and one non-heated rod. Through the tests, authors quantified the thermal safety margin for core cooling. In order to quantify the thermal safety margin, authors collected experimental data on post-CHF. The data are essential for the evaluation of clad temperature transient when core heat-up occurs during DBEs. In comparison with previous post-CHF tests, present experiments were performed in much wider experimental condition, covering high clad temperature, low to high pressure and low to high mass flux. Further, data at wider elevation (lower to higher elevation of core) were obtained in the present experiments, which make possible to discuss the effect of axial position on ...

Energy Technology Data Exchange (ETDEWEB)

Experience at SRS, ORNL, BNL, and Georgia Institute of Technology involving irradiated aluminum clad fuel and target elements, as well as studies of non-irradiated aluminum indicate that some types of aluminum assemblies can be kept in a continually well-deionized water atmosphere for up to 25 years without problems. SRS experience ranges from 2.75 years for the L-1.1 charge kept in deionized D{sub 2}O{sup 1} to greater than 10 years for assemblies stored in the Receiving Basin for Off-site Fuel (RBOF){sup 2}. Experience at Georgia Institute of Technology reactor in Atlanta yielded the longest value of 25 years without problems. The common denominators in all of the reports is that the water is continually deionized to approximately 2 M{Omega} (2 {times} 10{sup 6}ohms) resistivity and the containers for the water are stainless steel or other non-porous material. This resistivity value is equivalent to a value of 0.5 micromhos or microSiemens conductivity and is ...

Energy Technology Data Exchange (ETDEWEB)

We report tests of a refuelable zinc/air battery of modular, bipolar-cell design, intended for fleet electric busses and vans. The stack consists of twelve 250-cm{sup 2} cells built of two units: (1) a copper-clad glass-reinforced epoxy board supporting anode and cathode current collectors, and (2) polymer frame providing for air- and electrolyte distribution and zinc fuel storage. The stack was refueled in 4 min. by a hydraulic transfer of zinc particles entrained in solution flow.

Science.gov (United States)

This letter describes the first lasing experiment of the heterostructure semiconductor Raman laser with lateral confinement of both the Stokes and pump fields. It has a GaP Raman active layer with thickness of 10 ..mu..m and Al/sub 0.1/Ga/sub 0.9/P cladding layers. The stripe of the active layer has been fabricated by a plasma etching technique. Steps should be taken to realize the semiconductor Raman laser pumped by an injection laser, applicable to wideband optical communication.

Energy Technology Data Exchange (ETDEWEB)

A diffuse-reflectance capability for the Fourier transform infrared spectrometer at the Y-12 Plant Laboratory has been implemented. A sample cell with a 25 to 400/sup 0/C temperature-controlled sample stage and an ultrahigh-vacuum-to-atmospheric pressure gas-handling capability has been developed. Absorbance of light from the spectrometer beam, resulting from the beam being scattered from a powder sample, can be measured. This capability of detecting molecular species on and in powders is to be used to study chemisorption on actinide and rare-earth metals, alloys, and compounds. Cell design is described along with experiments demonstrating its performance in detecting moisture absorption on uranium oxide, moisture and carbon dioxide absorption on the lithium hydride/hydroxide system, and carbon dioxide absorption on potassium borohydride. 13 figures.

Energy Technology Data Exchange (ETDEWEB)

A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the ...

Energy Technology Data Exchange (ETDEWEB)

Thin passive layers of uranium nitride were formed by nitriding pure metallic uranium in non-equilibrium, low pressure radio-frequency plasma of nitrogen. Plasma nitriding at low substrate temperature of 230 C-250 C was found to cause the formation of adherent layers of uranium sesquinitride ({alpha}-U{sub 2}N{sub 3}) which provide a considerable protection against hydrogen attack. The characteristics of these passivation layers were determined by X-ray diffraction and Auger electron spectroscopy. The incipient hydriding kinetics of the plasma-treated samples were compared with those of untreated and nitrogen-ion implantation ones, utilizing a hot-stage microscope that was monitored continuously with a TV camera and videotape. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Today TBP and TBAs are the compounds which have the highest potential to replace the hydrides arsine and phosphine in the MOVPE process. The authors have demonstrated the entire material system Ga-In-As-P can be grown without any loss of quality using TBP and TBAs not only in one reactor, but in a complete family of reactors. These reactors range from small-scale single wafer R and D reactors to multiwafer Planetary Reactor systems. Both InP based and GaAs based materials could be grown with an excellent quality. Thus all growth processes for III-V devices--long and short wavelength lasers, LEDs, high speed transistors, etc.--can be switched to TBP and TBAs. This will drastically reduce safety hazards and lead to processes that have advantages both from the ecological and economical point of view.

British Library Electronic Table of Contents (United Kingdom)

''Hybrid'' hydrogen storage, where hydrogen is stored in both the solid material and as a high pressure gas in the void volume of the tank can improve overall system efficiency by up to 50% compared to either compressed hydrogen or solid materials alone. Thermodynamically, high equilibrium hydrogen pressures in metal-hydrogen systems correspond to low enthalpies of hydrogen absorption-desorption. This decreases the calorimetric effects of the hydride formation-decomposition processes which can assist in achieving high rates of heat exchange during hydrogen loading-removing the bottleneck in achieving low charging times and improving overall hydrogen storage efficiency of large hydrogen stores. Two systems with hydrogenation enthalpies close to -20kJ/mol H2 were studied to investigate the h...

Science.gov (United States)

During this reporting period the experimental apparatus was completed after substantial delays by the manufacturer. The equipment has been fully tested to familiarize the staff with its operating and safety procedures. An initial liquefaction study has begun on samples of Utah coal (60 microns or less) using 50 grams of iron-titanium alloy, 500 ml of tetralin, and 150 grams of powdered coal at 500/sup 0/F and 500 psig. Results will be available in the next quarterly report. A new researcher has been added to the project to address the hydrogen absorption of new and recycled alloy samples. 2 figs.

International Nuclear Information System (INIS)

Fuel rod failures produce a release of fission products into primary coolant system. Since nuclear power plants have licensing limits for the release of volatile fission products to the environment (off-gas limits) detailed monitoring of the development of clad failure is necessary. In case of fuel rod failure a release of fission products into the primary coolant system arises. Fission gases accumulated in the free volume of a fuel rod escape through the clad defect. Water entering the fuel rod reacts with fission products, forming volatile chemical compounds. These may escape in a similar manner into the fission gases. Other compounds may dissolve and may be carried outside the fuel rod as dissolved species. Consequently, the distribution of these fission products, in the cross section of the fuel rod, is modified. An implementation of the maximum entropy gamma computed tomography technique is used to obtain such distributions in the area of ...

International Nuclear Information System (INIS)

The effects of catalytic metal additives on the hydrogen desorption properties of the submicrocrystalline magnesium hydride (#beta#-MgH_2) formed after hydrogenation of the Mg + 10 wt.%X (X = V, Y, Zr) mechanically (ball) milled composites were studied. The composites with catalytic metals were processed by controlled mechanical milling (CMM) in the magneto-mill Uni Ball Mill 5 under protective Ar atmosphere. X-ray diffraction of the milled powders revealed the formation of Mg nanograins (50-60 nm range) interdispersed with the nanograined metal additives within the powder particles. Scanning electron microscopy showed particle size reduction after milling. After activation and hydrogenation in a Sieverts-type apparatus under about 2 MPa pressure of hydrogen, the tetragonal #beta#-MgH_2 hydride co-exists with the small amount of retained unreacted Mg phase and the small amount of MgO in all three composites. The #beta#-MgH_2 phase after ...

Energy Technology Data Exchange (ETDEWEB)

Composite particles represented as TiV{sub 2.1}Ni{sub 0.3}-Raney Ni(R) were prepared by ball-milling a TiV{sub 2.1}Ni{sub 0.3} alloy with Raney Ni in the presence of 0.01 M sodium hypophosphite (NaH{sub 2}PO{sub 2}) aqueous solution as a reducing agent. The composite particles had different morphology from original TiV{sub 2.1}Ni{sub 0.3} alloy particles and TiV{sub 2.1}Ni{sub 0.3}-Raney Ni composite particles prepared by the ball-milling in the absence of the NaH{sub 2}PO{sub 2} aqueous solution. In charge-discharge cycle tests, the TiV{sub 2.1}Ni{sub 0.3}-Raney Ni(R) composite electrode showed the maximum discharge capacity of 620 mAh g{sup -1}, while its cycle durability was similar to the TiV{sub 2.1}Ni{sub 0.3} alloy electrode, which was explained from depth profiles of constituent elements by Auger electron spectroscopy (AES). In thermogravimetry (TG) and differential thermal analysis (DTA), two steps of dehydriding for hydrided TiV{sub 2.1}Ni{sub 0.3}-Raney ...

International Nuclear Information System (INIS)

An effort to expand the irradiation mission of the Fast Flux Test Facility (FFTF) beyond testing fuels and materials for the liquid-metal reactor (LMR) program included a study of the feasibility of producing commercial quantities of "6"0Co. The "6"0Co would be produced by neutron capture in assemblies containing an array of natural cobalt pins and hydrogen-bearing moderator pins located at the periphery of the FFTF core. Adding hydrogenous material to the assemblies enhances "6"0Co production by slowing neutrons into energy ranges where the "5"9Co capture cross section is higher. Some of the moderated neutrons leak from the moderated region to adjacent fuel regions, increasing local fission rates. In order to validate calculated fission rates and establish calculational biases and uncertainties, experiments were conducted in the zero-power plutonium reactor (ZPPR) to measure fission rates in fuel regions adjacent to a mock-up of a cobalt production assembly. The ZPPR experiment and ...

Energy Technology Data Exchange (ETDEWEB)

Since 1999, several studies on nuclear fuels were realised in C11/C12 Atalante Hot Cell. This paper presents firstly an overview of the apparatus used for fuel dissolution and characterisation like reactor design, gas trapping flask and solid/liquid separation. Then, the general methodology is described as a function of fuel, temperature, reagents, showing for each step, the reachable experimental data: Dissolution rate, chemical and radiochemical fuel composition including volatile LLRN, insoluble mass, composition, morphology, cladding chemical, radiochemical and physical characterisation using SIMS (made in Cadarache/LECA facilities), MEB. To conclude, some of the obtained results on 129I and 14C composition of oxide fuels, rate of dissolution and first results on dissolution studies of RERTR UMo fuel will be detailed. (Author)

Energy Technology Data Exchange (ETDEWEB)

This research aims to develop reliable, advanced system thermal-hydraulic computer code and to quantify the uncertainties of code to introduce the best estimate methodology of ECCS for LBLOCA. Although the one of best estimate code, RELAP5/MOD3.1 was introduced from USNRC, several deficiencies in its reflood model and some improvements have been made. The improvements consist of modification of reflood wall heat transfer package and adjusting the drop size in dispersed flow regime. The tome smoothing of wall vaporization and level tracking model are also added to eliminate the pressure spike and level oscillation. For the verification of improved model and quantification of associated uncertainty, the FLECHT-SEASET data were used and upper limit of uncertainty at 95% confidence level is evaluated. (Author) 30 refs., 49 figs., 2 tabs.

International Nuclear Information System (INIS)

By varying different variables (potential, chloride content, surface pretreatment etc.) it is possible to show the effect of increasingly harsher corrosion conditions on passive-layer stability. These changes will not be detected by conventional methods e.g. measurement of passive current density, until a very late stage. Electrochemical noise measurement will allow the action of inhibitors to be detected in a rapid and effective manner. High-alloy steels and titanium claddings subjected to pitting corrosion in chloride-containing media demonstrate how to use this method for problem solutions and to open up new practical applications. The effect of mechanical stresses (natural, tensile) on the corrosion system can be detected by electrochemical noise which opens up new methods for crack corrosion studying and monitoring. (orig./DG).

Science.gov (United States)

Development of a shear and leach complex for UO/sub 2/-SS clad fuel was continued with major emphasis on the operation of a rotary drum leacher. Flooding data for nozzle plate pulse columns at high A/O ratios are reported. Engineering tests of dissolution of Zr--6% U alloy with HF in molten salt demonstrated a dissolution rate of 0.8 to 1.5 mg/cm/sup 2//min. Subsequent fluorination with 100% F/sub 2/ proceeded at half times of 40 to 135 min. The results of a high level waste calcination (run R-72) made with formaldehyde treated simulated Purex waste are reported. (auth)

International Nuclear Information System (INIS)

Zirconium alloys have anisotropic mechanical properties depending on their physical orientations and are widely used as nuclear materials such as cladding tube material. An operation condition of the nuclear reactor requires a high creep resistance, because it is subjected to long period operations, high temperature and high pressure. Generally, it takes a few days or months to do the creep experiment, so it is difficult to get a data in short period. However, there is a way to predict a creep property by using the stress-relaxation in the short term. These studies realized the stress-relaxation through a compressive test of HANA-6 (Zr-1.1Nb-0.05Cu) alloy that was developed by KAERI (Korea Atomic Energy Research Institute), and then predicted the creep property

International Nuclear Information System (INIS)

It is generally known that a number of metallic glasses have excellent corrosion resistance in a variety of chemically hostile environments. Consequently, the use of laser cladding to coat a massive crystalline material such as aluminium with a layer of a metallic glass has obvious advantages. In this paper, the authors will show that the formation of a predominantly amorphous layer of Zr_6_0Al_1_5NI_2_5 alloy by laser processing is possible, if the obstacles to amorphization are overcome. In addition, evidence of the excellent corrosion resistance of this alloy in a NaCl solution will be given. A comparative study of the corrosion behavior of this amorphous alloy with pure aluminium and Al-Cr alloy will be done, in order to complete previous studies of laser processed coatings of aluminum substrates.

Energy Technology Data Exchange (ETDEWEB)

Isotherms have been measured for H(D){sub 2}(g) solution in crystalline Pd{sub 9}Si{sub 2} in the temperature range from 235 to 373 K. The solubilities are significant, e.g., at 1.0 MPa (298 K), (H/Pd) = 0.052 or Pd{sub 9}Si{sub 2}H{sub 0.47}, however, there is no indication of hydride phase formation even down to 235 K at 1.0 MPa. The thermodynamic values for hydrogen solutions at infinite dilution of hydrogen are {Delta}H{degrees}{sub H}= -11.9 kJ/mole {1/2}H{sub 2} and {Delta}S{degrees}{sub H} = -50 J/K mole {1/2}H{sub 2}. The former is more negative than for Pd-H{sub 2} and the latter is somewhat more positive; but generally the values are not that different from Pd-H{sub 2}. The isotope effect is similar to that found for Pd-H(D){sub 2}.

International Nuclear Information System (INIS)

The search for alternative energy supplies continues since the oil crisis of 1973. One energy vector is dihydrogen, H_2. Of the group VI hydrides, water has been the focus of most studies in harnessing solar energy and generating H_2. Two basic photochemical strategies have been employed: molecular photocatalytic systems, and semiconductor based photocatalytic systems. The results have not met with the euphoric expectations of the mid-1970's because of the difficulties encountered in H_2O splitting (E"0 S"2 "-/S = + 0.51 eV, NHE) is another vehicle tapped as a potential source of H_2. Heterogeneous photocatalysis utilizing semiconductor particulates and sunlight as the photon source has been successful with interesting quantum efficiencies. To this end, novel photocatalytic devices have been developed; one of these uses two coupled semiconductors to achieve vectorial displacement of the photogenerated reducing and oxidizing equivalents. An important area in which ...

Energy Technology Data Exchange (ETDEWEB)

The mobility of metals in ground water is an important consideration for evaluating remedial options at the Asarco smelter site. Tacoma, Washington. One factor in assessing metal mobility is the degree of secondary mineralization in a slag-fill aquifer extending into the intertidal zone along the Puget Sound shoreline. Samples of aquifer material were collected for mineralogical analysis from borehole MW-206 at five-foot intervals within the slag fill from 5 to 25 feet below the ground surface, and in the underlying marine sand and gravel at 27 feet. Grab samples of slag fragments with visually apparent secondary minerals were also collected at five intermediate depths between 12 and 19 feet. Samples were analyzed by a variety of techniques including hydride generation/atomic absorption for arsenic concentration, scanning electron microscopy/electron microprobe for mineralogical texture and microanalysis, powder x-ray diffraction for mineral identification, and ...

International Nuclear Information System (INIS)

Molar heat capacities have been measured for VHsub(n) and NbHsub(n) with n up to 1.93 at temperatures between 1.5 and 16 K. The height of the peak in plots of the electronic specific heat, indicating superconductivity, diminishes with increasing hydrogen content in the #alpha# + #beta# two-phase region, and can be taken as a measure of the fractional amount of #alpha#-phase present (lever-rule). In NbHsub(n) accordingly, the two-phase region presumably extends up to n = approximately 0.9 at helium temperatures. No hydride phase, including VH_2 and NbH_2, showed superconductivity above 1.5 K. The measured #gamma#-coefficients of the V/H-alloys agree with APW band-structure calculations for V metal in the range 5 =< nsub(e) =< 7 of band electron concentration. They coincide with the #gamma#-coefficients of V/Cr-alloys reported in the literature. Hence VHsub(n) represents another example of the 'shifting bands' concept developed recently for PdHsub(n). (author).

Energy Technology Data Exchange (ETDEWEB)

The Electrochemical Technology Program at Argonne National Laboratory (ANL) provides advanced battery R&D; technology transfer to industry; technical analyses, assessments, modeling, and databases; and independent testing and post-test analyses of advanced batteries. These capabilities and services are being offered to the US Advanced Battery Consortium (USABC) and Cooperative Research and Development Agreements (CRADA) are being negotiated for USABC-sponsored work at ANL. A small portion of DOE`s cost share for USABC projects has been provided to ANL to continue R&D and testing activities on key technologies that were previously supported directly by DOE. This report summarizes progress on these USABC projects during the period of April I through September 30, 1992. In this report, the objective, background, technical progress, and status are described for each task. The work is organized into the following task areas: 1.0 Lithium/Sulfide Batteries; 2.0 Nickel/Metal ...

Energy Technology Data Exchange (ETDEWEB)

The conversion of off-peak surplus electricity into peak electricity through an electrolyzer, hydrogen storage, and fuel cell energy storage system was discussed. Development efforts in high pressure alkaline electrolysis and Proton-Exchange Membrane (PEM) fuel cells have improved the near-term viability of these systems. Potential use of wind turbines and other renewable energy-based generation systems, through hydrogen-based energy storage, were discussed as a new supply of surplus electricity. An integrated set of nomographs were presented for providing quick estimates of peak electricity costs derived from an electrolyzer/hydrogen fuel cell system. The nomographs allowed first order cost comparisons of centralized versus distributed hydrogen energy systems considering trade-offs between production economies of scale and hydrogen storage and transport costs. Use of the nomographs to compare centralized and dispersed systems was demonstrated. Results showed that all else being equal, ...

International Nuclear Information System (INIS)

An effective procedure for removing _3H, Xe and Kr from irradiated fuels was demonstrated using Shippingport UO"2 fuel. The release characteristics of _3H, Kr, Xe, and I from irradiated nuclear fuel have been determined as a function of temperature and gaseous environment. Vacuum outgassing and a flowing gas stream have been used to vary the gaseous environment. Vacuum outgassing released about 99% of the _3H and 20% of both Kr and Xe within a 3 h at 1500_0C. Similar results were obtained using a carrier gas of He containing 6% H"2. However, a carrier gas containing only He resulted in the release of approximately 80% of the _3H and 99% of both Kr and Xe. These results indicate that the release of these volatile fission products from irradiated nuclear fuel is a function of the chemical composition of the gaseous environment. The rate of tritium release increased with increasing temperature (1100 to 1500_0C) and with the addition of hydrogen to the gas stream. Using crushed UO"2 fuel ...

International Nuclear Information System (INIS)

TRIGA-SSR is a steady state research and material test reactor that has been in operation since 1980. The original TRIGA fuel was HEU (highly enriched uranium) with a U"2"3"5 enrichment of 93 per cent. Almost all TRIGA HEU fuel bundles are now burned-up. Part of the spent fuel was loaded and transferred to US, in a Romania - DOE arrangement. The rest of the TRIGA fuel bundles have to be temporarily stored in the TRIGA facility. As the storage conditions had to be established with caution, neutron and thermal hydraulic evaluations of the storage conditions were required. Some criticality evaluations were made based on the SAR (Safety Analysis Report) data. Fuel constant axial temperature approximation effect is usual for criticality computations. TRIGA-SSR fuel bundle geometry and materials model for SCALE5-CSAS module allows the introduction of a fuel temperature dependency for the entire fuel active height, using different materials for each fuel bundle region. Previous RELAP5 thermal ...

Energy Technology Data Exchange (ETDEWEB)

The first of three scheduled poolside fuel examinations at the Oyster Creek reactor conducted during February/March 1980, was directed at one of the four symmetrically loaded ENC 8 x 8 lead assemblies that had achieved a burnup of approx. 25,000 MWd/MTU. Forty-five of the fuel rods in assembly UD3-109 were removed and examined. In general, the individual fuel rods were in excellent condition. The average fuel rod diameter continued to decrease during the last cycle was assembly burnup increased from 19,500 to 25,700 MWd/MTU. The creepdown since the beginning of life (BOL) in the center of the fuel rods is about 0.003 in. The fuel rods bore no indication of cladding ridging. Fuel rod growth continued at a linear rate of about 0.02% per GWd/MTU burnup since BOL. Preliminary eddy current test data showed that the cladding was free of significant defects. Visual examination of fuel rods, spacers, and tie plate revealed no unusual conditions. An ...

Energy Technology Data Exchange (ETDEWEB)

Plans for the disposal of radioactive liquid and solid wastes presently stored in double-shell tanks at the Hanford Site call for retrieval and processing of the waste to create forms suitable for permanent disposal. Waste will be retrieved from a tank using a submerged slurry pump in conjunction with one or more rotating slurry jet mixer pumps. Pacific Northwest Laboratory (PNL) has conducted tests using simulated waste slurries to assess the effects of a impinging slurry jet on the corrosion rate of the tank wall and floor, an action that could potentially compromise the tank`s structural integrity. Corrosion processes were investigated on a laboratory scale with a simulated neutralized cladding removal waste (NCRW) slurry and in a subsequent test with simulated neutralized current acid waste (NCAW) slurry. The test slurries simulated the actual NCRW and NCAW both chemically and physically. The tests simulated those conditions expected to exist in the respective ...

International Nuclear Information System (INIS)

Fourteen irradiated Fast Flux Test Facility (FFTF) fuel pins were subjected to representative overpower transients in six flowing sodium loop experiments conducted in the TREAT reactor. The transient tests were extended to substantial overpower levels well beyond protected levels, with some tests intentionally run to failure to identify failure thresholds and characteristics. Test variables included transient ramp rate (5, 50, and 100 cents/s) and burnup (2 to 58 MWd/kg). Performance limits and failure characteristics were identified, and cladding strain and fuel melting data were obtained for development and verification of transient analysis codes. The test results demonstrated that FFTF Reference fuel pins are capable of surviving overpower levels well beyond the FFTF secondary Plant Protection System (PPS) trip limit of 1.25 times normal rated power. Based on analytical evaluations to interpolate and extrapolate test results to the full range of burnups and ...

Energy Technology Data Exchange (ETDEWEB)

Continuous-wave (cw) operation at temperatures up to 23 /sup 0/C of an Al/sub 0.26/Ga/sub 0.26/In/sub 0.48/P/Ga/sub 0.52/In/sub 0.48/P/ Al/sub 0.26/Ga/sub 0.26/In/sub 0.48/P double heterostructure (DH) laser has been achieved for the first time. The threshold current was 160 mA at 20 /sup 0/C for a device with a 10-..mu..m-wide and 250-..mu..m-long ion-implanted stripe geometry. The emission wavelength was 671 nm during cw operation at 10 /sup 0/C. To reduce thermal resistance to a heat sink, a dually stacked structure made of a thin (approx.0.3 ..mu..m) p-AlGaInP layer and a p-Al/sub 0.76/Ga/sub 0.24/As layer was used as a cladding layer. The DH wafer was grown by atmospheric pressure metalorganic chemical vapor deposition.

International Nuclear Information System (INIS)

In the VEGA program on radionuclide release from irradiated fuel under severe accident conditions, 10 tests in total were performed at JAEA from 1999 to 2004 under inert and steam atmospheres including the highest pressure or temperature conditions. These tests showed the increase in release rate above 2,800 K or at the fuel liquefaction and the decrease in release rate under elevated pressure, which was a first observation in the world. The data on low-volatility radionuclide release, release from MOX fuel, effect of fuel oxidation, and eutectic reaction with cladding on release were obtained from the tests. The mechanism of pressure effect on release was examined and a new release model with pressure effect was proposed. In addition, the pressure effect on source term evaluation and effectiveness of accident management measures were investigated. This article summarizes the major outcomes described above that have already been published and newly describes the ...

International Nuclear Information System (INIS)

The Sp-100 reactor is a lithium-cooled high-temperature fast-spectrum reactor. The fuel is UN. The cladding is fabricated from PWC-11, a Nb alloy, as are all the primary structural components. A reactor lifetime of up to ten years with an operating temperature of 1370 K is required. The accumulated fluence is expected to be 6 x10"2"2 n/cm"2. The damage, which could result in swelling or embrittlement, anneals out as fast as it occurs for the majority of the structure. This has been confirmed by earlier radiation testing. A number of components, however, are exposed to lower temperatures and the reactor design and materials selection for these components must take this into consideration. Radiation effects must also be considered for the UN fuel, bearing materials, etc. To data an instrumented experiment, MOTO 1000A, has been conducted in the FFTF reactor and as uninstrumented experiment SPM-1 in the EBR-II reactor. In this paper the post-irradiation examination and ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents the new thermal hydraulic models describing the hydrodynamics of the solid fuel/steel chunks during an LMFBR hypothetical core-disruptive accident. These models, which account for two-way coupling between the solid and fluid phases, describe the mass, momentum, and energy exchanges which occur when the chunks are present at any axial location. They have been incorporated in LEVITATE, a code for the analysis of fuel and cladding dynamics under Loss-of-Flow (LOF) conditions. Their influence on fuel motion is presented in the context of the L6 TREAT experiment analysis. It is shown that the overall hydrodynamic behavior of the molten fuel and solid-fuel chunks is dependent on both the size of the chunks and the power level. At low and intermediate power levels the fuel motion is more dispersive when small chunks, rather than large ones, are present. At high power levels the situation is reversed. These effects are explained in detail.

Energy Technology Data Exchange (ETDEWEB)

The electrometallurgical treatment process described in this paper builds on our experience in treating spent fuel from the Experimental Breeder Reactor (EBR-II). The work is also to some degree, a spin-off from applying electrometallurgical treatment to spent fuel from the Hanford single pass reactors (SPRs) and fuel and flush salt from the Molten Salt Reactor Experiment (MSRE) in treating EBR-II fuel, we recover the actinides from a uranium-zirconium fuel by electrorefining the uranium out of the chopped fuel. With SPR fuel, uranium is electrorefined out of the aluminum cladding. Both of these processes are conducted in a LiCl-KCl molten-salt electrolyte. In the case of the MSRE, which used a fluoride salt-based fuel, uranium in this salt is recovered through a series of electrochemical reductions. Recovering high-purity uranium from an aluminum-matrix fuel is more challenging than treating SPR or EBR-II fuel because the aluminum- matrix fuel is typically -90% ...

Energy Technology Data Exchange (ETDEWEB)

Burnable poisons are used in nuclear reactors to produce a more level distribution of power in the reactor core and to reduce to necessity for a large control system. An ideal burnable poison would burn at the same rate as the fuel. In this study, separation of neutron-absorbing isotopes was investigated in order to eliminate isotopes that remain as absorbers at the end of fuel life, thus reducing useful fuel life. The isotopes Gd-157, Dy-164, and Er-167 were found to have desirable properties. These isotopes were separated from naturally occurring elements by means of plasma separation to evaluate feasibility and cost. It was found that pure Gd-157 could save approximately $6 million at the end of four years. However, the cost of separation, using the existing facility, made separation cost- ineffective. Using a magnet with three times the field strength is expected to reduce the cost by a factor of ten, making isotopically separated burnable poisons a favorable method of increasing ...

International Nuclear Information System (INIS)

A suspension-firing type radioactive waste incineration system is developed and cold demonstration testing of ceramic filters for the system are carried out. The incineration system, which is useful for a wide variety of waste materials, can serve to simplify the facilities and to reduce the costs for waste disposal. The incineration system can be used for drying-processing of concentrated waste liquids and disposal of flame resistant materials including ion exchange resins and rubber, as well as for ordinary combustible solid materials. An on-line backwash system is adopted to allow the ceramic filters to operate stably for a long period of time. For one-step filtering using the ceramic filter, the decontamination factor is greater than 10"5 for the processing of various wastes. In a practical situation, there exist vapor produced by the spray drier and the cladding in used ion exchange resin, which act to increase the decontamination performance of the ceramic ...

International Nuclear Information System (INIS)

During 17 years since the start of operation of the first commercial LWR in Japan, many LWRs have experienced various corrosion damages, but the causes of them were clarified, and the counter-measures were executed effectively in actual plants, as the results, the cause of corrosion damage decreased remarkably, and now, the high rate of operation has become to be maintained. In this paper, the major cases of corrosion damage experienced in LWRs in Japan and foreign countries, the causes of them and the countermeasures, the problems of hereafter and so on are described. The corrosion damage of metallic materials in the environment of LWRs occurs in the parts in contact with high temperature, high pressure water and steam, such as stainless steel piping in the primary cooling system of BWRs, and nickel alloy heating tubes of steam generators, carbon steel feed water piping and zirconium alloy fuel cladding tubes in PWRs. Recently, accompanying the advance of LWR ...

International Nuclear Information System (INIS)

Further to a cost-benefit analysis of the various medium-term and long-term and H.L.W. storage possibilities, C.E.A. (French Atomic Energy Commission) and S.G.N. decided to develop an original dry storage process with natural convection cooling that offers many advantages: cut in the total investment and operating costs; high operating safety; natural convection cooling; existence of two containment barriers irrespective of the assumed clad conditions; flexible, modular and compact design. The process was first implemented in the so-called CASCAD Cadarache Facility (vault-type facility) constructed in Cadarache mainly to store fuel from Brennilis heavy water reactor. For the purpose, a large program was set up to develop and validate computer codes, in particular with the use of mockups. On the request of many clients, and owing to the outstanding operating results of the CASCAD Cadarache Facility, SGN was brought to adapt the process to the storage of other types ...

International Nuclear Information System (INIS)

The TRAC/PFI-MOD2 Version 5.3 code was assessed against six FLECHT-SEASET forced reflood tests (31504, 31203, 31302, 31701, 34209, and 31922) and two cylindrical core test facility (CCTF) tests [C1-19 and C2-6]. The objective of this study was to evaluate the clad thermal response predictive capabilities of the code with the newly added reflood model under large-break loss-of-coolant accident (LOCA) conditions in a pressurized water reactor (PWR). The TRAC model for the FLECHT-SEASET test facility was developed from a RELAP5 model. The test section was modeled using a vessel component with 23 axial levels, 1 radial ring, and 1 azimuthal cell. Test inlet and exit conditions were modeled using fill and break components, respectively. The measured lower and upper plenum test conditions were input to the model. The electrically heated rod was modeled using a rod component with 22 axial mesh points. The axial boundary of each mesh point coincided with a fluid cell ...

Science.gov (United States)

Stresses commonly present in AlGaAs/GaAs laser heterostructures were reduced using Molecular Beam Epitaxy grown Al/sub 0.3/Ga/sub 0.7/P/sub 0.01/As/sub 0.99/ cladding layers. The Al/sub 0.3/Ga/sub 0.7/P/sub 0.01/As/sub 0.99/ alloy was grown using an incident P/sub 2/ flux of roughly-equal1 x 10/sup 14//cm/sup 2/ indicating a sticking coefficient of 0.1 at a substrate temperature of 600 /sup 0/C. X-ray automatic Bragg angle control curvature measurements were used to monitor the residual heteroepitaxial stress. Broadened double crystal x-ray linewidths indicated the occurrence of alloy grading and broadened interfaces. The effects of P concentration and film thickness on stress and on the existence of a misfit dislocation grid are discussed.

Energy Technology Data Exchange (ETDEWEB)

Production of cermet nuclear fuel having fine uranium dioxide (UO{sub 2}) particles dispersed in matrix metal requires basic property data on the compatibility of matrix metal with fission product compounds. It is thermodynamically suggested that, as burnup increases, cesium in oxide fuel reacts with the fuel, other fission products or cladding pipe and produces cesium uranates, cesium molybdate, or cesium chromate in stainless steel cladding pipe. Attempt was made to measure the thermal expansion coefficient and thermal conductivity of cesium uranates (Cs{sub 2}UO{sub 4} and Cs{sub 2}U{sub 2}O{sub 7}), cesium molybdate (Cs{sub 2}MoO{sub 4}) and cesium chromate (Cs{sub 2}CrO{sub 4}). Thermal expansion was measured by X-ray diffraction and determined by Cohen`s method. Thermal conductivity was obtained by measuring thermal diffusion by laser flash method. The thermal expansion of Cs{sub 2}UO{sub 4} and Cs{sub 2}U{sub 2}O{sub 7} is as low as 1.2% ...

Energy Technology Data Exchange (ETDEWEB)

Trihydroxynaphthalene reductase catalyzes two intermediate steps in the fungal melanin biosynthetic pathway. The enzyme, a typical short-chain dehydrogenase, is the biochemical target of three commercial fungicides. The fungicides bind preferentially to the NADPH form of the enzyme. Three X-ray structures of the Magnaporthe grisea enzyme complexed with NADPH and two commercial and one experimental fungicide were determined at 1.7 {angstrom} (pyroquilon), 2.0 {angstrom} (2,3-dihydro-4-nitro-1H-inden-1-one, 1), and 2.1 {angstrom} (phthalide) resolutions. The chemically distinct inhibitors occupy similar space within the enzyme's active site. The three inhibitors share hydrogen bonds with the side chain hydroxyls of Ser-164 and Tyr-178 via a carbonyl oxygen (pyroquilon and 1) or via a carbonyl oxygen and a ring oxygen (phthalide). Active site residues occupy similar positions among the three structures. A buried water molecule that is hydrogen bonded to the NZ nitrogen of Lys-182 ...

Energy Technology Data Exchange (ETDEWEB)

This proceedings volume is organized into seven sections that reflect the materials systems and issues of electrochemical materials R and D in batteries, fuel cells, and capacitors. The first three parts are largely devoted to lithium ion rechargeable battery materials since that electrochemical system has received much of the attention from the scientific community. Part 1 discusses cathodes for lithium ion rechargeable batteries as well as various other battery systems. Part 2 deals with electrolytes and cell stability, and Part 3 discusses anode developments, focusing on carbon and metal oxides. Part 4 focuses on another rechargeable system that has received substantial interest, nickel/metal hydride battery materials. The next two parts discuss fuel cells--Part 5 deals with Proton Exchange Membrane (PEM) fuel cells, and Part 6 discusses oxide materials for solid oxide fuel cells. The former has the benefit of operating around room temperature, whereas the ...

International Nuclear Information System (INIS)

The effect of phosphorus on the corrosion resistance of Al-bronzes is studied in detail in this work. A literature review showed that there are a lot of things known about the microstructure and the mechanical properties of Al-bronzes. In spite of their corrosion resistance the corrosion properties and the structure of the protective oxide films of Al-bronzes were seldom a matter of interest. Systematic studies of the influence of different alloying elements on the oxide film and the corrosion properties are rare. Therefore, it is not possible to predict the corrosion resistance of Al-bronzes, made by alloying particular elements. The high corrosion resistance of the new alloy CuAl_2_0P_1 was the reason to investigate the influence of phosphorus on the corrosion properties of Al-bronzes in more detail. A systematic study of the microstructure and the corrosion properties of Cu, CuP_x, CuAl_2_0 and CuAl_2_0P_x offers an insight into the effect of aluminium and phosphorus on the ...

International Nuclear Information System (INIS)

Studies are made in this program to enhance our understanding of the role of 5f electrons in chemical bonding. Most of our studies on the macroscopic scale emphasize certain isotopes available from the National Transplutonium Production Program centered at HFIR/TRU -namely, _9_6"2"4"8Cm, _9_7"2"4"9Bk, _9_8"2"4"9Cf, _9_9"2"5"3Es, and _9_9"2"5"4Es. Particular classes of compounds, such as hydrides, chalcogenides, and pnictides are often selected for study on the basis of their utility in bringing out significant chemical differences between the lanthanides and the actinides. High temperature/high pressure experiments on actinide metals and compounds reveal characteristics about the degree of 5f electron localization as a function of atomic number in the series. Magnetic properties of metals and compounds are investigated using ultra-sensitive methods and hydration numbers of ions in solution are investigated by neutron scattering at HFIR. As a result of a recently ...

Energy Technology Data Exchange (ETDEWEB)

In this work, wet ball milling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ball milling method, wet ball milling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ball milled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ball milled MgH{sub 2} powder. Although after ball milling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ball milled MgH{sub 2} powder is larger than that of dry ball milled MgH{sub 2} powder due to the lubricant effect of solvent THF during wet ball milling. The improved particle size and specific surface area of wet ball milled MgH{sub 2} powder is found to be determining its hydrogen sorption kinetics especially at relatively ...

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Energy and environment are two major concerns in our modern society due to the coming shortage in fossil energy sources and the growing of greenhouse gas emissions. The challenge for the coming years is to discover new energy resources and to develop devices that are compatible with a sustainable development and generate few (or zero) emission. One of these devices is the fuel cell feed by hydrogen, whose application fields are very large. In particular, the proton exchange membrane fuel cell (PEMFC) is the most realistic device for automotive application. However, hydrogen storage remains one of the most important challenges regarding its development. Although different techniques are available for storing hydrogen, no ideal solution has been found yet. Compression needs elaborated tanks in shape for supporting high pressures, liquefaction requires an expensive hydrogen cooling and adapted tanks. Chemical storage by hydrides ...

Energy Technology Data Exchange (ETDEWEB)

This proceedings volume comprises 17 papers on the following subjects: Methane hydrates, compounds of gas and water; Compressed air stroage gas turbine power plants / Scheduled application for load levelling between varying wind power production and power demand; Modern pumped storage power stations in the GW range - the PSW Goldisthal example; Lead batteries - new developments and future applications; Alkaline battery systems for hybrid electric road vehicles; Lighium systems and their applications; Zinc/air cells; Hydrogen storage - metal hydride storage, compressed gas storage, LNG storage; Carbon nanofibres for hydrogen storage; Double-layer condensers - technology, cost, perslpectives; Supercondensers in motor vehicles; Superconducting magnetic energy stores; Flywheel storage - status report; Decentralized energy storage in the European integrated supply grid - the EU project DISPOWER; Intercontinental integration of power supply - perspectives of full-scale ...

Energy Technology Data Exchange (ETDEWEB)

Pipeline automated ultrasonic testing (AUT) uses fully automated equipment that travels around a pipe on a welding band in a linear scan to allow array pulses to provide ultrasound information on weld zones. Pipeline AUT is also used for zone discrimination as well as with special calibration blocks, dual gate output displays, and rapid defect sizing. AUT allows for the inspection of welds soon after completion, and can save construction costs by process control when combined with engineering critical assessment (ECA) to minimize rejection rates. Ultrasonic phased arrays (UPA) use an array of elements that are all individually wired, pulsed, and time-shifted. Elements are pulsed in groups of approximately 16 elements at a time for pipeline welds. Phased arrays can be used to combine electronic scanning, sectorial scanning and precision focusing to give a practical combination of displays. Optimum angles can be selected for welds and other components, and the electronic scanning ...

International Nuclear Information System (INIS)

This study deals with testing the capacity of the code PARET to simulate natural circulation phenomena under different boundary conditions in addition to assessment of some new options related to simulation of control rod movement and the reactivity effect of thermal expansion fuel elements. the experiments of the simple thermal hydraulic loop of Missouri University about natural circulation phenomena in narrow parallel channel were used to validate the code. The results indicate good agreements regarding the evolution of coolant velocity and clad temperature. In particular the heat transfer coefficient of natural convection has been calculated in good agreement with the experiment. On the other hand, the core of MNSR reactor has been modelled to stimulate the reactor dynamic behaviour under natural circulation condition for different initial power level. The observed oscillations during the initial phase vanish gradually with passing time. In this context three ...

International Nuclear Information System (INIS)

Important steady-state thermohydraulic parameters of the TRIGA research reactor operating under natural convection mode of coolant flow were investigated using NCTRIGA computer code. Neutronic parameters used in preparing the input of NCTRIGA were taken from the analysis performed by 3-D Monte Carlo code MCNP4C. Benchmarking of the NCTRIGA calculated results were performed against the experimental data measured by the thermocouples in the instrumented fuel element (IFE) during the steady state operation of the reactor under natural convection mode of coolant flow. Various thermohydraulic parameters like the coolant velocity, flow rate and mass flow rate were generated for the hot channel as well as for the two channels comprising instrumented fuels. Calculated peak fuel temperatures at different power levels were compared with the measured values and also with the calculations performed by PARET code. Axial temperature profile at the fuel centreline, fuel surface and coolant in the hot ...

Science.gov (United States)

We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantum-well (MQW) structures. These structures, grown at 775 [degree]C by metalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6[degree] towards P(111)[r angle][l angle]111[r angle]A, consist of nominally undoped MQWs surrounded by doped In[sub 0.49]Al[sub 0.51]P cladding layers to form [ital p]-[ital i]-[ital n] diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In[sub 0.49]Ga[sub 0.51]P/In[sub 0.49](Al[sub 0.5]Ga[sub 0.5])[sub 0.51]P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg doping profile, confirming the importance of Mg diffusion and unintentional background doping in these materials. Our results show that (InAlGa)P materials are promising for ...

International Nuclear Information System (INIS)

In Japan, the development of next-generation Light Water Reactor has been launched since April 2008. The development program will be completed in 2015. The purpose of development is to cope with the replacement for existing nuclear power plants after 2030 in Japan and the expanding demand for nuclear power in the world; 'Nuclear Renaissance.' The reactor also aims to be global standard at around 2030. The requirements for global standard and domestic users have been investigated through the feasibility study of past 2 years, 2006-2007, and six innovative features or 'Core-Concepts' were established as follows. A) Reactor core system with uranium enrichment above 5% for significant decrease of spent fuel discharge and prominent higher availability B) Long-life materials and innovative water chemistry technologies for 80 years plant lifetime and significant reduction of occupational dose C) Seismic isolation technologies to standardize plant design independent from site conditions D) ...

Energy Technology Data Exchange (ETDEWEB)

The Fixed Bed Nuclear Reactor (FBNR) is a small 40 MWe reactor based on the Pressurized Water Reactor (PWR) technology. FBNR is an integrated primary circuit and simple in design. It has the characteristics of being small, modular, proliferation resistant, inherently safe and passively cooled reactor with reduced adverse environmental impact. It utilizes the fuel designed for high temperature reactors operating in a relatively low temperature of PWR environment The 15 mm diameter spherical fuel elements are made of TRISO type microspheres embedded in graphite and cladded by SiC. The coolant flow transfers them from the fuel chamber into the core and become fixed forming a suspended core. Any accident signal will cut off the power to the coolant pump causing a stop in the flow. This results in making the fuel elements fall out of the reactor core by the force of gravity and return into the fuel chamber where they are passively cooled under subcritical condition. ...

Science.gov (United States)

A critical review of the literature revealed no experiments on uranyl ion transfer from an aqueous to a tributyl phosphate phase which positively measured the kinetics of the chemical reaction at the interphase. Drawing isorhythmic lines on a three component diagram gives a complex correlation for the compaction of three sizes of glass beads. Neither the use of thoria sols nor high feed solution concentrations of thorium nitrate gave any significant increase in mean particle diameters over those obtained from nitrate solutions of lower concentrations in flame denitration. A hydraulic film resistance has been detected in the anion exchange of uranyl sulfate into Dowex 2lK, and chloride elution was found to give a higher apparent uranium diffusion coefficient than nitrate elution. The rate of dissolution of mixed thorium-uranium oxides was determined as a function of the per cent of mixed oxides dissolved. Mixing in tanks packed with boron glass Raschig rings ...

Science.gov (United States)

AlGaInP double heterostructure laser diodes with a GaInP active layer constitute a basic laser structure for visible-light lasers using an AlGaInP alloy system. This paper gives a detailed description of (Al/sub x/Ga/sub 1 - x/)/sub 0.5/In/sub 0.5/P metalorganic vapor phase epitaxial growth, laser-fabrication processes, and basic device-characteristics for these lasers. The obtained pulsed-threshold-current was about 3.8 kA/cm/sup 2/(3.2 kA/cm/sup 2/ minimum) for laser diodes with an 8-10 /n//m wide and 150-300 ..mu..m long injection stripe. High characteristic-temperature T/sub o/ for the temperature dependence of pulsed threshold current was obtained and was found to be dependent on band-gap-energy differences between active layers and cladding layers. The maximum value for T/sub o/ was 222 K. The lasing wavelength of an AlGaInP double heterostructure laser diode with a GaInP active layer was found to depend on growth conditions and dopant behaviour during the ...

Energy Technology Data Exchange (ETDEWEB)

The Control Rod Drive(CRD) nozzles for PWR nuclear power plants(NPP) house the control rod drives. The number of nozzle penetrations range from the mid-30's to over 100 in each reactor head. The integrity of CRD nozzles is very important, because the primary pressure boundary is established with the J-groove weld joining the nozzle to the head clad surface. The Alloy 600 PWSC CRD nozzle leaks discovered in the fall of 2000 and spring of 2001 in several US plants. Therefore the NRC has recommended a more proactive effort by US utilities to inspect similarly susceptible nozzles in all US plants. The primary safety concern is circumferential cracks that can permit the nozzles to separate from the head at high velocity and produce a large-break leak in the reactor vessel. A secondary concern is head leakage from any through-wall cracks in the nozzle or J-groove weld area. Numerous inspection and repair tools have been developed to address CRD nozzle inspection ...