Heavy element research

International Nuclear Information System (INIS)

Anon.

1976-01-01

Heavy element research activities in metallurgy and ceramics during 1976 at Lawrence Berkeley Laboratory are reviewed. Topics include: microstructure, properties and alloy design; ceramic alloy program; high resolution and high voltage electron microscopy; and powder metallurgy

Neutrinoless ββ decay mediated by the exchange of light and heavy neutrinos: the role of nuclear structure correlations

Science.gov (United States)

Menéndez, J.

2018-01-01

Neutrinoless β β decay nuclear matrix elements calculated with the shell model and energy-density functional theory typically disagree by more than a factor of two in the standard scenario of light-neutrino exchange. In contrast, for a decay mediated by sterile heavy neutrinos the deviations are reduced to about 50%, an uncertainty similar to the one due to short-range effects. We compare matrix elements in the light- and heavy-neutrino-exchange channels, exploring the radial, momentum transfer and angular momentum-parity matrix element distributions, and considering transitions that involve correlated and uncorrelated nuclear states. We argue that the shorter-range heavy-neutrino exchange is less sensitive to collective nuclear correlations, and that discrepancies in matrix elements are mostly due to the treatment of long-range correlations in many-body calculations. Our analysis supports previous studies suggesting that isoscalar pairing correlations, which affect mostly the longer-range part of the neutrinoless β β decay operator, are partially responsible for the differences between nuclear matrix elements in the standard light-neutrino-exchange mechanism.

Applications of a global nuclear-structure model to studies of the heaviest elements

International Nuclear Information System (INIS)

Moeller, P.; Nix, J.R.

1993-01-01

We present some new results on heavy-element nuclear-structure properties calculated on the basis of the finite-range droplet model and folded-Yukawa single-particle potential. Specifically, we discuss calculations of nuclear ground-state masses and microscopic corrections, α-decay properties, β-decay properties, fission potential-energy surfaces, and spontaneous-fission half-lives. These results, obtained in a global nuclear-structure approach, are particularly reliable for describing the stability properties of the heaviest elements

On the production of heavy elements by cold fusion

International Nuclear Information System (INIS)

Armbruster, P.

1985-01-01

After a short historical introduction (Section 1), this article presents new insights into the mechanism limiting the fusion of heavy nuclides (Section 2). Fusion is finally limited by the increasing Coulomb forces in the formation process of a compound system, as well as in its deexcitation. Moreover, nuclear structure effects in all stages of evaporation residue (EVR) formation are shown to be of importance. The wide field of fusion reaction studies and possible experimental techniques is projected onto the task of element synthesis, and only those aspects that are of relevance here are covered. The better understanding of EVR formation (Section 2) and the new experimental techniques (Section 3) that enabled the production of elements 107-109 (Section 4) are also discussed. In Section 5 ground-state properties and the nuclear structure of the heaviest isotopes, together with their production cross sections, are discussed. Finally, an outlook on how eventually to go beyond Z = 109 is given

Heavy water moderated tubular type nuclear reactor

International Nuclear Information System (INIS)

Oohashi, Masahisa.

1986-01-01

Purpose: To enable to effectively change the volume of heavy water per unit fuel lattice in heavy water moderated pressure tube type nuclear reactors. Constitution: In a nuclear reactor in which fuels are charged within pressure tubes and coolants are caused to flow between the pressure tubes and the fuels, heavy water tubes for recycling heavy water are disposed to a gas region formed to the outside of the pressure tubes. Then, the pressure tube diameter at the central portion of the reactor core is made smaller than that at the periphery of the reactor core. Further, injection means for gas such as helium is disposed to the upper portion for each of the heavy water tubes so that the level of the heavy water can easily be adjusted by the control for the gas pressure. Furthermore, heavy water reflection tubes are disposed around the reactor core. In this constitution, since the pitch for the pressure tubes can be increased, the construction and the maintenance for the nuclear reactor can be facilitated. Also, since the liquid surface of the heavy water in the heavy water tubes can be varied, nuclear properties is improved and the conversion ratio is improved. (Ikeda, J.)

Superheavy Element Synthesis and Nuclear Structure

International Nuclear Information System (INIS)

Ackermann, D.

2009-01-01

The search for the next closed proton and neutron shells beyond 2 08P b has yielded a number of exciting results in terms of the synthesis of new elements [1,2,3]. The superheavy elements (SHE), however, are a nuclear structure phenomenon. They owe their existence to the quantum mechanical origin of shell correction energies without which they would not be bound. In recent years the development of efficient experimental set-ups including separators and advanced particle and photon detection arrangements allowed for more and more detailed nuclear structure studies for nuclei at and beyond Z=100. A review of those recent achievements is given in ref. [4]. Among the most interesting features is the observation of K-isomeric states. Experimentally about 14 cases have been identified in the region of Z>96 as shown in Fig. 1. K-isomers or indications of their existence have been found for almost all even-Z elements in the region Z=100 to 110. We could recently establish and/or confirm such states in the even-even isotopes 2 52,254N o [5]. The heaviest nucleus where such a state was found is 2 70D s with Z=110 as we reported in 2001 [6]. Those nuclear structure studies lay out the grounds for a detailed understanding of these heavy and high-Z nuclear systems, and contribute at the same time valuable information to preparation of strategies to successfully continue the hunt for the localisation of the next spherical proton and neutron shells after 2 08P b. The recent activities for both SHE synthesis and nuclear structure investigations at GSI will be reported.(author)

Physical particularities of nuclear reactors using heavy moderators of neutrons

Energy Technology Data Exchange (ETDEWEB)

Kulikov, G. G., E-mail: ggkulikov@mephi.ru; Shmelev, A. N. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)

2016-12-15

In nuclear reactors, thermal neutron spectra are formed using moderators with small atomic weights. For fast reactors, inserting such moderators in the core may create problems since they efficiently decelerate the neutrons. In order to form an intermediate neutron spectrum, it is preferable to employ neutron moderators with sufficiently large atomic weights, using {sup 233}U as a fissile nuclide and {sup 232}Th and {sup 231}Pa as fertile ones. The aim of the work is to investigate the properties of heavy neutron moderators and to assess their advantages. The analysis employs the JENDL-4.0 nuclear data library and the SCALE program package for simulating the variation of fuel composition caused by irradiation in the reactor. The following main results are obtained. By using heavy moderators with small neutron moderation steps, one is able to (1) increase the rate of resonance capture, so that the amount of fertile material in the fuel may be reduced while maintaining the breeding factor of the core; (2) use the vacant space for improving the fuel-element properties by adding inert, strong, and thermally conductive materials and by implementing dispersive fuel elements in which the fissile material is self-replenished and neutron multiplication remains stable during the process of fuel burnup; and (3) employ mixtures of different fertile materials with resonance capture cross sections in order to increase the resonance-lattice density and the probability of resonance neutron capture leading to formation of fissile material. The general conclusion is that, by forming an intermediate neutron spectrum with heavy neutron moderators, one can use the fuel more efficiently and improve nuclear safety.

Physical particularities of nuclear reactors using heavy moderators of neutrons

International Nuclear Information System (INIS)

Kulikov, G. G.; Shmelev, A. N.

2016-01-01

In nuclear reactors, thermal neutron spectra are formed using moderators with small atomic weights. For fast reactors, inserting such moderators in the core may create problems since they efficiently decelerate the neutrons. In order to form an intermediate neutron spectrum, it is preferable to employ neutron moderators with sufficiently large atomic weights, using "2"3"3U as a fissile nuclide and "2"3"2Th and "2"3"1Pa as fertile ones. The aim of the work is to investigate the properties of heavy neutron moderators and to assess their advantages. The analysis employs the JENDL-4.0 nuclear data library and the SCALE program package for simulating the variation of fuel composition caused by irradiation in the reactor. The following main results are obtained. By using heavy moderators with small neutron moderation steps, one is able to (1) increase the rate of resonance capture, so that the amount of fertile material in the fuel may be reduced while maintaining the breeding factor of the core; (2) use the vacant space for improving the fuel-element properties by adding inert, strong, and thermally conductive materials and by implementing dispersive fuel elements in which the fissile material is self-replenished and neutron multiplication remains stable during the process of fuel burnup; and (3) employ mixtures of different fertile materials with resonance capture cross sections in order to increase the resonance-lattice density and the probability of resonance neutron capture leading to formation of fissile material. The general conclusion is that, by forming an intermediate neutron spectrum with heavy neutron moderators, one can use the fuel more efficiently and improve nuclear safety.

Heavy metals and related trace elements

International Nuclear Information System (INIS)

Leland, H.V.; Luoma, S.N.; Wilkes, D.J.

1977-01-01

A review is given of heavy metals and related trace elements in the aquatic environment. Other reviews and bibliographies are cited, dealing with the metabolism and transport of metal ions and with the toxic effects of stable and radioactive trace metals on aquatic organisms. The sources of trace elements in natural waters are discussed. It is suggested that atmospheric inputs of several trace metals comprise sizable fractions of total inputs to the Great Lakes and continental shelf waters. Information on stack emissions of trace elements from a coal-fired steam plant was used to estimate the likely range of air concentrations and inputs to a forested watershed in Tennessee. Some basic concepts of cycling of elements through aquatic communities were examined, such as the Pb, Mn and Zn concentrations in sediment and estuarine plants and animals colonizing dredge-spoil disposal areas. The use of plants as biological indicators of trace element contamination was outlined, as well as bioaccumulation in aquatic fauna. The effects of environmental factors on the kinetics of element exchange were noted, for example the influx rates of Cs 137 in tubificid worms, and Co 60 and Zn 65 in shrimp were shown to be temperature dependent. The toxicity of heavy metals on aquatic fauna was discussed, such as the histopathological lesions in the kidney and liver of fishes caused by heavy metals, and the effects of Hg and Cu on the olfactory response of rainbow trout

Determination of trace elements and heavy metals in agricultural products cultivated at the Rimac river valley in Lima city using nuclear and related analytical techniques

OpenAIRE

Bedregal, Patricia; Torres, Blanca; Olivera, Paula; Mendoza, Pablo; Ubillús, Marco; Creed-Kanashiro, H.; Penny, M.; Junco, J.; Ganoza, L.

2004-01-01

There are strong indications that the Rimac river valley is being contaminated with heavy metals and an excess of trace elements that come from some industrial and mining activities developed along the Rimac river valley. The agricultural products cultivated there in could be suffering the same effect. Nuclear and related analytical techniques will play an important role in the study of pollution by providing information concerning the degree of contamination in some agricultural products cul...

Nuclear fuel element

International Nuclear Information System (INIS)

Penrose, R.T.; Thompson, J.R.

1976-01-01

A method of protecting the cladding of a nuclear fuel element from internal attack and a nuclear fuel element for use in the core of a nuclear reactor are disclosed. The nuclear fuel element has disposed therein an additive of a barium-containing material and the barium-containing material collects reactive gases through chemical reaction or adsorption at temperatures ranging from room temperature up to fuel element plenum temperatures. The additive is located in the plenum of the fuel element and preferably in the form of particles in a hollow container having a multiplicity of gas permeable openings in one portion of the container with the openings being of a size smaller than the size of the particles. The openings permit gases and liquids entering the plenum to contact the particles. The additive is comprised of elemental barium or a barium alloy containing one or more metals in addition to barium such as aluminum, zirconium, nickel, titanium and combinations thereof. 6 claims, 3 drawing figures

New approach to description of fusion-fission dynamics in super-heavy element formation

International Nuclear Information System (INIS)

Zagrebaev, V.I.

2002-01-01

A new mechanism of the fusion-fission process for a heavy nuclear system is proposed, which takes place in the (A 1 , A 2 ) space, where A 1 and A 2 are two nuclei, surrounded by a certain number of shared nucleons ΔA. The nuclei A 1 and A 2 gradually lose (or acquire) their individualities with increasing (or decreasing) a number of collectivized nucleons ΔA. The driving potential in the (A 1 , A 2 ) space is derived, which allows the calculation of both the probability of the compound nucleus formation and the mass distribution of fission and quasi-fission fragments in heavy ion fusion reactions. The cross sections of super-heavy element formation in the 'hot' and 'cold' fusion reactions have been calculated up to Z CN =118. (author)

Nuclear physics with heavy ions. 1

International Nuclear Information System (INIS)

Reif, R.; Schmidt, R.

1981-01-01

Some results obtained in nuclear physics with heavy ions in the energy range up to 10 MeV/nucleon are summarized. A short review of the tendencies in the development of heavy ion accelerators is followed by a classification of the mechanisms observed in heavy ion interactions. The characteristics of the various types of reactions are presented. Applications of heavy ion beams in other branches of sciences are discussed. (author)

Quantum mechanical theory of positron production in heavy ion collisions with nuclear contact

International Nuclear Information System (INIS)

Heinz, U.

1986-01-01

The interplay between atomic and nuclear interactions in heavy ion collisions with nuclear contact is studied. The general theoretical description is outlined and analyzed in a number of different limits (semiclassical approximation, DWBA, fully quantal description). The two most important physical mechanisms for generating atomic-nuclear interference, i.e., energy conservation and the introduction of additional phase shifts by nuclear reactions, are extracted. The resulting typical coupling matrix elements are analyzed for their relative importance in atomic and nuclear excitations. The description of nuclear influence on atomic excitations in terms of a classical time delay caused by nuclear reactions is reviewed, and its relationship to the underlying quantal character of the nuclear reaction is discussed. The theory is applied to spontaneous positron emission in supercritical heavy-ion collisions (Z/sub tot/ ≥ 173). It is shown that nuclear contact can lead to line structures in the positron energy spectra if the probability distribution for nuclear delay times caused by the contact has contributions for T ≥ 10 -19 sec. We explicitly evaluate a model where a pocket in the internuclear potential near the touching configuration leads to formation of nuclear molecules, and predict a resonance-like excitation function for the positron peak. 25 refs., 7 figs

Actinide targets for the synthesis of super-heavy elements

International Nuclear Information System (INIS)

Roberto, J.B.; Alexander, C.W.; Boll, R.A.; Burns, J.D.; Ezold, J.G.; Felker, L.K.; Hogle, S.L.; Rykaczewski, K.P.

2015-01-01

Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of "4"8Ca beams on actinide targets. These target materials, including "2"4"2Pu, "2"4"4Pu, "2"4"3Am, "2"4"5Cm, "2"4"8Cm, "2"4"9Cf, and "2"4"9Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including "2"4"9Bk, "2"5"1Cf, and "2"5"4Es are described.

Synthesis of superheavy elements and application of nuclear physics methods in related fields

International Nuclear Information System (INIS)

Flerov, G.

1985-01-01

Heavy ion accelerators are used not only for the synthesis of new elements but also for the production of nuclear filters from polymers. The principle is described of the manufacture of such filters, and their chemical processing. By changes in irradiation conditions and in conditions of chemical leaching, nuclear filters may be obtained of various density, shape and size of pores and with a different angular distribution of tracks in the polymer material. The most frequently used polymer is polyethylene terephthalate film. The uses are described of nuclear filters, such as water treatment in the production of semiconductor instruments, in cryogenic instruments, in the purification concentration and sterilization filtration of viruses and vaccines, etc. Other uses of heavy ion beams are suggested, such as the method of nuclear tracks, the manufacture of membranes with a single opening, the manufacture of laser diaphragms, lithography, etc. (E.S.)

Nuclear fission induced by heavy ions

International Nuclear Information System (INIS)

Newton, J.O.

1988-09-01

Because the accelerators of the 50's and 60's mostly provided beams of light ions, well suited for studying individual quantum states of low angular momentum or reactions involving the transfer of one or two nucleons, the study of fission, being an example of large-scale collective motion, has until recently been outside of the mainstream of nuclear research. This situation has changed in recent years, due to the new generation of accelerators capable of producing beams of heavy ions with energies high enough to overcome the Coulomb barriers of all stable nuclei. These have made possible the study of new examples of large-scale collective motions, involving major rearrangements of nuclear matter, such as deep-inelastic collisions and heavy-ion fusion. Perhaps the most exciting development in the past few years is the discovery that dissipative effects (nuclear viscosity) play an important role in fission induced by heavy ions, contrary to earlier assumptions that the viscosity involved in fission was very weak and played only a minor role. This review will be mainly concerned with developments in heavy-ion induced fission during the last few years and have an emphasis on the very recent results on dissipative effects. Since heavy-ion bombardment usually results in compound systems with high excitation energies and angular momenta, shell effects might be expected to be small, and the subject of low energy fission, where they are important, will not be addressed. 285 refs., 58 figs

Charged particle induced delayed X-rays (DEX) for the analysis of intermediate and heavy elements

Science.gov (United States)

Pillay, A. E.; Erasmus, C. S.; Andeweg, A. H.; Sellschop, J. P. F.; Annegarn, H. J.; Dunn, J.

1988-12-01

The emission of K X-rays from proton-rich and metastable radionuclides, following proton activation of the stable isotopes of the elements of interest, has not been widely used as a means of analysis. The thrust of this paper proposes a nuclear technique using delayed X-rays for the analysis of low concentrations of intermediate and heavy elements. The method is similar to the delayed gamma-ray technique. Proton bombardment induces mainly (p, n) reactions whereas the delayed X-rays originate largely from e --capture and isomeric transition. Samples of rare earth and platinum group elements (PGE), in the form of compacted powders, were irradiated with an 11 MeV proton beam and delayed X-rays detected with a 100 mm 2 Ge detector. Single element spectra for a range of rare earths and PGEs are presented. Analytical conditions are demonstrated for Pd in the range 0.1-5%. Spectra from actual geological samples of a PGE ore, preconcentrated by fire-assay, and monazite are presented. All six platinum group elements are visible and interference-free in a single spectrum, a marked advance on other nuclear techniques for these elements, including PIXE and neutron activation analysis (NAA).

Heavy Metallic Element Distribution in Cisadane River Estuary's Water and Sediment

OpenAIRE

M. Taufik Kaisupy; Abdul Rozak; Endang Rochyatun

2006-01-01

Observation of heavy metallic elements in Cisadane River Estuary has been done in July and November 2005. The results show that heavy metallic elements content in seawater is lower and still below the treshold value stated by government for fisheries. There was an indication of heavy metallic elements on sediment. Distribution of Pb on July and of Cu on November 2005 were found higher near the coast and decrease towards the sea, and commonly were found in front of estuary such as Cisadane, Mu...

Nuclear fuel element

International Nuclear Information System (INIS)

Mogard, J.H.

1977-01-01

A nuclear fuel element is disclosed for use in power producing nuclear reactors, comprising a plurality of axially aligned ceramic cylindrical fuel bodies of the sintered type, and a cladding tube of metal or metal alloys, wherein said cladding tube on its cylindrical inner surface is provided with a plurality of slightly protruding spacing elements distributed over said inner surface

Nuclear Matrix Elements for the $\\beta\\beta$ Decay of the $^{76}$Ge

CERN Document Server

Brown, B A; Horoi, M

2015-01-01

The nuclear matrix elements for two-neutrino double-beta (2 n$\\beta\\beta$ ) and zero-neutrino double-beta (0 n$\\beta\\beta$) decay of 76 Ge are evaluated in terms of the configuration interaction (CI), quasiparticle random phase approximation (QRPA) and interacting boson model (IBM) methods. We show that the decomposition of the matrix elements in terms of interemediate states in 74 Ge is dominated by ground state of this nucleus. We consider corrections to the CI results that arise from configurations admixtures involving orbitals out-side of the CI configuration space by using results from QRPA, many-body-perturbation theory, and the connections to related observables. The CI two-neutrino matrix element is reduced due to the inclusion of spin-orbit partners, and to many-body correlations connected with Gamow-Teller beta decay. The CI zero-neutrino matrix element for the heavy neutrino is enhanced due to particle-particle correlations that are connected with the odd-even oscillations in the nuclear masse...

Nuclear fuel element

International Nuclear Information System (INIS)

1974-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed. A heat conducting fission product retaining metal liner of a refractory metal is incorporated in the fuel element between the cladding and the nuclear fuel to inhibit mechanical interaction between the nuclear fuel and the cladding, to isolate fission products and nuclear fuel impurities from contacting the cladding, and to improve the axial thermal peaking gradient along the length of the fuel rod. The metal liner can be in the form of a tube or hollow cylindrical column, a foil of single or multiple layers in the shape of a hollow cylindrical column, or a coating on the internal surface of the cladding. Preferred refractory metal materials are molybdenum, tungsten, rhenium, niobium and alloys of the foregoing metals

Nuclear fuel element

International Nuclear Information System (INIS)

Thompson, J.R.; Rowland, T.C.

1976-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed. A heat conducting, fission product retaining metal liner of a refractory metal is incorporated in the fuel element between the cladding and the nuclear fuel to inhibit mechanical interaction between the nuclear fuel and the cladding, to isolate fission products and nuclear fuel impurities from contacting the cladding and to improve the axial thermal peaking gradient along the length of the fuel rod. The metal liner can be in the form of a tube or hollow cylindrical column, a foil of single or multiple layers in the shape of a hollow cylindrical column, or a coating on the internal surface of the cladding. Preferred refractory metal materials are molybdenum, tungsten, rhenium, niobium and alloys of the foregoing metals

Interactions of relativistic heavy ions in thick heavy element targets and some unresolved problems

International Nuclear Information System (INIS)

Brandt, R.; Ditlov, V.A.; Pozharova, E.A.; Smirnitskij, V.A.

2005-01-01

Interactions of relativistic heavy ions with total energies above 30 GeV in thick Cu and Pb targets (≥2 cm) have been studied with various techniques. Radiochemical irradiation experiments using thick Cu targets, both in a compact form or as diluted '2π-Cu targets' have been carried out with several relativistic heavy ions, such as 44 GeV 12 C (JINR, Dubna) and 72 GeV 40 Ar (LBL, Berkeley, USA). Neutron measuring experiments using thick targets irradiated with various relativistic heavy ions up to 44 GeV 12 C have been performed at JINR. In addition, the number of 'black prongs' in nuclear interactions (due to protons with energies less than 30 MeV and emitted from the target-like interaction partner at rest) produced with 72 GeV 22 Ne ions in nuclear emulsion plates has been measured in the first nuclear interaction of the primary 22 Ne ion and in the following second nuclear interaction of the secondary heavy (Z>1) ion. Some essential results have been obtained. 1) Spallation products produced by relativistic secondary fragments in interactions ([44 GeV 12 C or 72 GeV 40 Ar]+Cu) within thick copper yield less products close to the target and much more products far away from the target as compared to primary beam interactions. This applies also to secondary particles emitted into large angles (Θ>10deg). 2) The neutron production of 44 GeV 12 C within thick Cu and Pb targets is beyond the estimated yield as based on experiments with 12 GeV 12 C. These rather independent experimental results cannot be understood with well-accepted nuclear reaction models. They appear to present unresolved problems

Nuclear physics and heavy element research at LLNL

Energy Technology Data Exchange (ETDEWEB)

Stoyer, M A; Ahle, L E; Becker, J A; Bernstein, L A; Bleuel, D L; Burke, J T; Dashdorj, D; Henderson, R A; Hurst, A M; Kenneally, J M; Lesher, S R; Moody, K J; Nelson, S L; Norman, E B; Pedretti, M; Scielzo, N D; Shaughnessy, D A; Sheets, S A; Stoeffl, W; Stoyer, N J; Wiedeking, M; Wilk, P A; Wu, C Y

2009-05-11

This paper highlights some of the current basic nuclear physics research at Lawrence Livermore National Laboratory (LLNL). The work at LLNL concentrates on investigating nuclei at the extremes. The Experimental Nuclear Physics Group performs research to improve our understanding of nuclei, nuclear reactions, nuclear decay processes and nuclear astrophysics; an expertise utilized for important laboratory national security programs and for world-class peer-reviewed basic research.

Transplutonium elements - a literature survey

International Nuclear Information System (INIS)

Sivaramakrishnan, C.K.; Jadhav, A.V.

1974-01-01

The report surveys reported work on the discovery of transplutonium elements and their production through various methods like bombardment of heavy elements with charged ions, successive neutron captures on heavy elements in reactors and multiple neutron captures by heavy elements during nuclear explosions. Estimated yields of transplutonium elements in special targets irradiated in reactors, and also as byproducts from spent power reactor fuels are quoted. Various chemical procedures adopted for recovery of these elements from irradiated target and also from power reactor fuel reprocessing streams are described. A brief survey of shielded facilities available at various centres for transplutonium programmes is also included. Major uses of some of these heavy elements are described. (author)

Heavy Metallic Element Distribution in Cisadane River Estuary's Water and Sediment

Directory of Open Access Journals (Sweden)

M. Taufik Kaisupy

2006-04-01

Full Text Available Observation of heavy metallic elements in Cisadane River Estuary has been done in July and November 2005. The results show that heavy metallic elements content in seawater is lower and still below the treshold value stated by government for fisheries. There was an indication of heavy metallic elements on sediment. Distribution of Pb on July and of Cu on November 2005 were found higher near the coast and decrease towards the sea, and commonly were found in front of estuary such as Cisadane, Muara Saban and Tanjung Pasir. High Pb and Zn distributions on November 2005 were found only in front of Cisadane estuary. Cd distribution of Cisadane estuary was constant at all station but did not show any correlation with the distance of station and estuary. The Cd content on July and November 2005 is lower than 0,001 ppm. Generally, heavy metallic elements content have a uniform distribution at all stations inspite of its distance to estuary.

Lattice results for heavy light matrix elements

International Nuclear Information System (INIS)

Soni, A.

1994-09-01

Lattice results for heavy light matrix elements are reviewed and some of their implications are very briefly discussed. Despite the fact that in most cases the lattice results for weak matrix elements at the moment have only a modest accuracy of about 20--30% they already have important phenomenological repercussions; e.g. for V td /V ts , x s /x d and B → K*γ

Nuclear physics with polarized heavy ions

International Nuclear Information System (INIS)

Fick, D.; Grawert, G.; Turkiewicz, I.M.

1992-01-01

Polarized heavy ion beams ( 6 Li, 7 Li, 23 Na) have been in use as tools for the investigation of nuclear scattering and nuclear reactions for almost two decades. This review attempts to survey the research activities in this field with reference to nuclear structure, nuclear dynamics and reaction mechanisms. Besides reviewing the results from full quantum mechanical coupled channels analyses of data, special attention is paid to handwaving arguments and semiclassical pictures as a complementary way of obtaining a better understanding of the relevant physics. (orig.)

THE PROPERTIES OF HEAVY ELEMENTS IN GIANT PLANET ENVELOPES

Energy Technology Data Exchange (ETDEWEB)

Soubiran, François; Militzer, Burkhard [Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 (United States)

2016-09-20

The core-accretion model for giant planet formation suggests a two-layer picture for the initial structure of Jovian planets, with heavy elements in a dense core and a thick H–He envelope. Late planetesimal accretion and core erosion could potentially enrich the H–He envelope in heavy elements, which is supported by the threefold solar metallicity that was measured in Jupiter’s atmosphere by the Galileo entry probe. In order to reproduce the observed gravitational moments of Jupiter and Saturn, models for their interiors include heavy elements, Z , in various proportions. However, their effect on the equation of state of the hydrogen–helium mixtures has not been investigated beyond the ideal mixing approximation. In this article, we report results from ab initio simulations of fully interacting H–He– Z mixtures in order to characterize their equation of state and to analyze possible consequences for the interior structure and evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and SiO{sub 2}, we show that the behavior of heavy elements in H–He mixtures may still be represented by an ideal mixture if the effective volumes and internal energies are chosen appropriately. In the case of oxygen, we also compute the effect on the entropy. We find the resulting changes in the temperature–pressure profile to be small. A homogeneous distribution of 2% oxygen by mass changes the temperature in Jupiter’s interior by only 80 K.

Relativistic heavy-atom effects on heavy-atom nuclear shieldings

Science.gov (United States)

Lantto, Perttu; Romero, Rodolfo H.; Gómez, Sergio S.; Aucar, Gustavo A.; Vaara, Juha

2006-11-01

The principal relativistic heavy-atom effects on the nuclear magnetic resonance (NMR) shielding tensor of the heavy atom itself (HAHA effects) are calculated using ab initio methods at the level of the Breit-Pauli Hamiltonian. This is the first systematic study of the main HAHA effects on nuclear shielding and chemical shift by perturbational relativistic approach. The dependence of the HAHA effects on the chemical environment of the heavy atom is investigated for the closed-shell X2+, X4+, XH2, and XH3- (X =Si-Pb) as well as X3+, XH3, and XF3 (X =P-Bi) systems. Fully relativistic Dirac-Hartree-Fock calculations are carried out for comparison. It is necessary in the Breit-Pauli approach to include the second-order magnetic-field-dependent spin-orbit (SO) shielding contribution as it is the larger SO term in XH3-, XH3, and XF3, and is equally large in XH2 as the conventional, third-order field-independent spin-orbit contribution. Considering the chemical shift, the third-order SO mechanism contributes two-thirds of the difference of ˜1500ppm between BiH3 and BiF3. The second-order SO mechanism and the numerically largest relativistic effect, which arises from the cross-term contribution of the Fermi contact hyperfine interaction and the relativistically modified spin-Zeeman interaction (FC/SZ-KE), are isotropic and practically independent of electron correlation effects as well as the chemical environment of the heavy atom. The third-order SO terms depend on these factors and contribute both to heavy-atom shielding anisotropy and NMR chemical shifts. While a qualitative picture of heavy-atom chemical shifts is already obtained at the nonrelativistic level of theory, reliable shifts may be expected after including the third-order SO contributions only, especially when calculations are carried out at correlated level. The FC/SZ-KE contribution to shielding is almost completely produced in the s orbitals of the heavy atom, with values diminishing with the principal

Exploration of (super-)heavy elements using the Skyrme-Hartree-Fock model

International Nuclear Information System (INIS)

Erler, Jochen

2011-01-01

Motivated by the steadily increasing number of known nuclei and nuclear properties, theories of nuclear structure are presently a field of intense research. This work concentrates on the self-consistent description of nuclei in terms of the Skyrme-Hartree-Fock (SHF) approach. The extrapolation of nuclear shell structure to the region of super-heavy elements (SHE) using the SHF model, the dependence on different parameterization and the influence of collective correlation will be studied. The general scope of this work are large scale calculation for a global survey of properties of SHE like binding energies, separation energies and decay characteristics and lifetimes. These calculations were done in a collaboration with the theory group of the GSI in Darmstadt and have the aim to develop a database of lifetimes and reaction rates for α, β-decay and spontaneous fission in a very wide range with proton numbers 86 ≤ Z ≤ 120 and neutron numbers up to N ∼ 260 relevant for the astrophysical r-process. The results of this study for example predictions of a possible islands of very stable nuclei and information of favored decay mode for each nuclei are also applicable in the recent experimental synthesis of exotic SHE. For these calculation a framework to calculate β-decay half-lives within the SHF model has been developed and the existing axial SHF code has been extended to compute β-transition matrix elements and so to provide an estimation of half-lives. (orig.)

Exploration of (super-)heavy elements using the Skyrme-Hartree-Fock model

Energy Technology Data Exchange (ETDEWEB)

Erler, Jochen

2011-01-31

Motivated by the steadily increasing number of known nuclei and nuclear properties, theories of nuclear structure are presently a field of intense research. This work concentrates on the self-consistent description of nuclei in terms of the Skyrme-Hartree-Fock (SHF) approach. The extrapolation of nuclear shell structure to the region of super-heavy elements (SHE) using the SHF model, the dependence on different parameterization and the influence of collective correlation will be studied. The general scope of this work are large scale calculation for a global survey of properties of SHE like binding energies, separation energies and decay characteristics and lifetimes. These calculations were done in a collaboration with the theory group of the GSI in Darmstadt and have the aim to develop a database of lifetimes and reaction rates for {alpha}, {beta}-decay and spontaneous fission in a very wide range with proton numbers 86 {<=} Z {<=} 120 and neutron numbers up to N {approx} 260 relevant for the astrophysical r-process. The results of this study for example predictions of a possible islands of very stable nuclei and information of favored decay mode for each nuclei are also applicable in the recent experimental synthesis of exotic SHE. For these calculation a framework to calculate {beta}-decay half-lives within the SHF model has been developed and the existing axial SHF code has been extended to compute {beta}-transition matrix elements and so to provide an estimation of half-lives. (orig.)

Survival and compound nucleus probability of super heavy element Z = 117

Energy Technology Data Exchange (ETDEWEB)

Manjunatha, H.C. [Government College for Women, Department of Physics, Kolar, Karnataka (India); Sridhar, K.N. [Government First grade College, Department of Physics, Kolar, Karnataka (India)

2017-05-15

As a part of a systematic study for predicting the most suitable projectile-target combinations for heavy-ion fusion experiments in the synthesis of {sup 289-297}Ts, we have calculated the transmission probability (T{sub l}), compound nucleus formation probabilities (P{sub CN}) and survival probability (P{sub sur}) of possible projectile-target combinations. We have also studied the fusion cross section, survival cross section and fission cross sections for different projectile-target combination of {sup 289-297}Ts. These theoretical parameters are required before the synthesis of the super heavy element. The calculated probabilities and cross sections show that the production of isotopes of the super heavy element with Z = 117 is strongly dependent on the reaction systems. The most probable reactions to synthetize the super heavy nuclei {sup 289-297}Ts are worked out and listed explicitly. We have also studied the variation of P{sub CN} and P{sub sur} with the mass number of projectile and target nuclei. This work is useful in the synthesis of the super heavy element Z = 117. (orig.)

Reaction mechanisms for the synthesis of the heaviest elements from heavy ion reactions

International Nuclear Information System (INIS)

Gaeggeler, H.W.

1988-10-01

This review paper concerns fusion reactions with light heavy-ions, cold fusion, transfer reactions using light heavy-ions or heavy ions. In two appendices, methods for the separation and detection of nuclides in the domain of heaviest elements are described and a comment on the discovery of the element 104 is given. 51 figs., 10 tabs., 335 refs

Survival and compound nucleus probability of super heavy element Z = 117

International Nuclear Information System (INIS)

Manjunatha, H.C.; Sridhar, K.N.

2017-01-01

As a part of a systematic study for predicting the most suitable projectile-target combinations for heavy-ion fusion experiments in the synthesis of "2"8"9"-"2"9"7Ts, we have calculated the transmission probability (T_l), compound nucleus formation probabilities (P_C_N) and survival probability (P_s_u_r) of possible projectile-target combinations. We have also studied the fusion cross section, survival cross section and fission cross sections for different projectile-target combination of "2"8"9"-"2"9"7Ts. These theoretical parameters are required before the synthesis of the super heavy element. The calculated probabilities and cross sections show that the production of isotopes of the super heavy element with Z = 117 is strongly dependent on the reaction systems. The most probable reactions to synthetize the super heavy nuclei "2"8"9"-"2"9"7Ts are worked out and listed explicitly. We have also studied the variation of P_C_N and P_s_u_r with the mass number of projectile and target nuclei. This work is useful in the synthesis of the super heavy element Z = 117. (orig.)

HEAVY-ELEMENT ENRICHMENT OF A JUPITER-MASS PROTOPLANET AS A FUNCTION OF ORBITAL LOCATION

International Nuclear Information System (INIS)

Helled, R.; Schubert, G.

2009-01-01

One possible mechanism for giant planet formation is disk instability in which the planet is formed as a result of gravitational instability in the protoplanetary disk surrounding the young star. The final composition and core mass of the planet will depend on the planet's mass, environment, and the planetesimal accretion efficiency. We calculate heavy-element enrichment in a Jupiter-mass protoplanet formed by disk instability at various radial distances from the star, considering different disk masses and surface density distributions. Although the available mass for accretion increases with radial distance (a) for disk solid surface density (σ) functions σ = σ 0 a -α with α 5 years of planetary evolution, when the planet is extended and before gap opening and type II migration take place. The accreted mass is calculated for disk masses of 0.01, 0.05, and 0.1 M sun with α = 1/2, 1, and 3/2. We show that a Jupiter-mass protoplanet can accrete 1-110 M + of heavy elements, depending on the disk properties. Due to the limitation on the accretion timescale, our results provide lower bounds on heavy-element enrichment. Our results can explain the large variation in heavy-element enrichment found in extrasolar giant planets. Since higher disk surface density is found to lead to larger heavy-element enrichment, our model results are consistent with the correlation between heavy-element enrichment and stellar metallicity. Our calculations also suggest that Jupiter could have formed at a larger radial distance than its current location while still accreting the mass of heavy elements predicted by interior models. We conclude that in the disk instability model the final composition of a giant planet is strongly determined by its formation environment. The heavy-element abundance of a giant planet does not discriminate between its origin by either disk instability or core accretion.

Nuclear fuel element leak detection system

International Nuclear Information System (INIS)

John, C.D. Jr.

1978-01-01

Disclosed is a leak detection system integral with a wall of a building used to fabricate nuclear fuel elements for detecting radiation leakage from the nuclear fuel elements as the fuel elements exit the building. The leak detecting system comprises a shielded compartment constructed to withstand environmental hazards extending into a similarly constructed building and having sealed doors on both ends along with leak detecting apparatus connected to the compartment. The leak detecting system provides a system for removing a nuclear fuel element from its fabrication building while testing for radiation leaks in the fuel element

Origin of the chemical elements

Energy Technology Data Exchange (ETDEWEB)

Tayler, R J

1984-05-01

The subject is discussed in relation to the composition of initially created matter and changes which have occurred during the life history of the universe, with particular reference to our galaxy and nearby galaxies. Headings are: observations of element abundances (stars, gas clouds in our own and nearby galaxies, hot gas in galaxy clusters, the solar system); the originally created matter (Big Bang theory and early nuclear reactions); processes changing observed composition (galactic evolution; nuclear fusion reactions in stellar interiors; chemical composition of a highly evolved massive star); supernovae (production of heavy elements); chemical evolution of the galaxy; production of very heavy elements (s process, r process).

X-ray spectroscopy of highly ionized heavy ions as an advanced research for controlled nuclear fusion power

International Nuclear Information System (INIS)

Zschornack, G.; Musiol, G.

1988-01-01

Diagnostics and modelling of nuclear fusion plasmas require a detailed knowledge of atomic and molecular data for highly ionized heavy ions. Experimental verification of atomic data is made on the basis of IAEA recommendations using the method of high-resolution wavelength-dispersive X-ray spectroscopy in order to obtain contributions extensioning the available atomic data lists. Basic facilities for producing highly charged heavy ions are the electron-ion rings of the heavy ion collective accelerator and the electron beam ion source KRYON-2 at the Joint Institute for Nuclear Research at Dubna. For high-resolution X-ray spectroscopy with these sources a computer-aided crystal diffraction spectrometer has been developed the precision of which is achieved by using advanced principles of measurement and control. Relativistic atomic structure calculations have been carried out for a great number of elements and configurations to obtain data in ionization regions heavily accessible to the experiment. (author)

Heavy quark energy loss in nuclear medium

International Nuclear Information System (INIS)

Zhang, Benr-Wei; Wang, Enke; Wang, Xin-Nian

2003-01-01

Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark

Research in heavy-ion nuclear physics

International Nuclear Information System (INIS)

Sanders, S.J.; Prosser, F.W.

1992-01-01

This report discusses the following topics: Fusion-fission in light nuclear systems; High-resolution Q-value measurement for the 24 Mg+ 24 Mg reaction; Heavy-ion reactions and limits to fusion; and Hybrid MWPC-Bragg curve detector development

Nuclear fuel elements

International Nuclear Information System (INIS)

Nakai, Keiichi

1983-01-01

Purpose: To decrease the tensile stresses resulted in a fuel can as well as prevent decladding of fuel pellets into the bore holes by decreasing the inner pressure within the nuclear fuel element. Constitution: A fuel can is filled with hollow fuel pellets, inserted with a spring for retaining the hollow fuel pellets with an appropriate force and, thereafter, closely sealed at the both ends with end plugs. A cylindrical body is disposed into the bore holes of the hollow fuel pellets. Since initial sealing gases and/or gaseous nuclear fission products can thus be excluded from the bore holes where the temperature is at the highest level, the inner pressure of the nuclear fuel element can be reduced to decrease the tensile strength resulted to the fuel can. Furthermore, decladding of fuel pellets into the bore holes can be prevented. (Moriyama, K.)

Nuclear dynamics in heavy ion induced fusion-fission reactions

International Nuclear Information System (INIS)

Kapoor, S.S.

1992-01-01

Heavy ion induced fission and fission-like reactions evolve through a complex nuclear dynamics encountered in the medium energy nucleus-nucleus collisions. In the recent years, measurements of the fragment-neutron and fragment-charged particle angular correlations in heavy ion induced fusion-fission reactions, have provided new information on the dynamical times of nuclear deformations of the initial dinuclear complex to the fission saddle point and the scission point. From the studies of fragment angular distributions in heavy ion induced fission it has been possible to infer the relaxation times of the dinuclear complex in the K-degree of freedom and our recent measurements on the entrance channel dependence of fragment anisotropies have provided an experimental signature of the presence of fissions before K-equilibration. This paper reviews recent experimental and theoretical status of the above studies with particular regard to the questions relating to dynamical times, nuclear dissipation and the effect of nuclear dissipation on the K-distributions at the fission saddle in completely equilibrated compound nucleus. (author). 19 refs., 9 figs

Heavy Quark and Quarkonium Transport in High Energy Nuclear Collisions

Energy Technology Data Exchange (ETDEWEB)

Zhou, Kai [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China); Institute for Theoretical Physics, Johann Wolfgang Goethe-University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Frankfurt Institute for Advanced Studies, Ruth-Moufang-Str. 1, D-60438 Frankfurt am Main (Germany); Dai, Wei [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China); Xu, Nu [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Zhuang, Pengfei [Physics Department, Tsinghua University and Collaborative Innovation Center of Quantum Matter, Beijing 100084 (China)

2016-12-15

The strong interaction between heavy quarks and the quark gluon plasma makes the open and hidden charm hadrons be sensitive probes of the deconfinement phase transition in high energy nuclear collisions. Both the cold and hot nuclear matter effects change with the colliding energy and significantly influence the heavy quark and charmonium yield and their transverse momentum distributions. The ratio of averaged quarkonium transverse momentum square and the elliptic flow reveal the nature of the QCD medium created in heavy ion collisions at SPS, RHIC and LHC energies.

Heavy Quark and Quarkonium Transport in High Energy Nuclear Collisions

International Nuclear Information System (INIS)

Zhou, Kai; Dai, Wei; Xu, Nu; Zhuang, Pengfei

2016-01-01

The strong interaction between heavy quarks and the quark gluon plasma makes the open and hidden charm hadrons be sensitive probes of the deconfinement phase transition in high energy nuclear collisions. Both the cold and hot nuclear matter effects change with the colliding energy and significantly influence the heavy quark and charmonium yield and their transverse momentum distributions. The ratio of averaged quarkonium transverse momentum square and the elliptic flow reveal the nature of the QCD medium created in heavy ion collisions at SPS, RHIC and LHC energies.

The fabrication of nuclear fuel elements in Mexico

International Nuclear Information System (INIS)

Guerrero Morillo, H.L.

1977-01-01

The situation of the nucleoelectrical generation in Mexico by 1976 is described: two nuclear reactors under construction but no defined program on the type and start-up dates for the next power plants. However the existence of a general plan on nuclear power plants is mentioned, which, according to the last estimates reaches to 10,000 MW installed by 1990. The national intension, definitely expressed in the Law, is to supply domestic nuclear fuel to the power reactors operating in the country, starting with the first reload for the two BWR's at the first national station in Laguna Verde, which will be required at the end of 1981 and of 1982, respectively. Before such circumstances and the relatively short amounts of fuel elements that should be produced for those two unique reactors, Mexico already has to adopt a strategy to follow in respect to fuel elements fabrication. The two main options are analyzed: 1. To delay the local fabrication until a National Nuclear Program may be defined, meanwhile purchasing abroad the necessary reloads and initial cores; and 2. To start as soon as possible the local fuel elements fabrication in order to supply fuel for the first reload of the first unit of Laguna Verde, confronting the economical risks of such posture with the advantages of an immediate action. Both options are analyzed in detail comparing them specially under the economic point of view, standing out immediately the big effect of some factors which are economically imponderable, as experience and independance that would be gained with the second option. Emphasis is made on the advantages and risks of any case. According to the first option and once a National Program is defined, the work would be heavy but of simple strategy. On the contrary, the second option requires the adoption of a more complicated strategy, as either the project of the factory as its initial operation should be made under transient conditions, in view of the expected future expansion still

Study of the behaviour of some heavy elements in solvents containing hydrogen fluoride

International Nuclear Information System (INIS)

Tarnero, M.

1967-01-01

The anhydrous liquid mixtures: dinitrogen tetroxide-hydrogen fluoride and antimony pentafluoride-hydrogen fluoride were studied as solvents for heavy elements interesting nuclear energy: uranium, thorium, zirconium and for some of their compounds. For N 2 O 4 -HF mixtures, electric conductivity measurements and liquid phase infrared spectra were also obtained. Uranium and zirconium tetrafluoride are much more soluble in N 2 O 4 -HF mixtures than in pure hydrogen fluoride. Uranium dissolved in these mixtures is pentavalent. In SbF 5 -HF mixtures, uranium dissolves with hydrogen evolution and becomes trivalent. The solid compound resulting from the dissolution is a fluoro-antimonate: U(SbF 6 ) 3 . (author) [fr

Elements from chlorine to calcium nuclear reactions

CERN Document Server

Kunz, Wunibald

1968-01-01

Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

Development of heavy load carrying vehicle for nuclear power station

International Nuclear Information System (INIS)

Terabayashi, Yasuharu; Oono, Hiroo; Aizu, Takao; Kawaguchi, Kaname; Yamanaka, Masayuki; Hirobe, Tamio; Inagaki, Yoshiaki.

1985-01-01

In nuclear power stations, in order to carry out sound and stable operation, the routine inspection and regular inspection of machinery and equipment are performed, therefore, the transportation of heavy things is frequently carried out. Especially, the transportation of heavy things over the steps of passages and stairs requires much labor. Therefore, Chubu Electric Power Co., Inc. and Chubu Plant Service Co., Ltd. carried out the research on the development of a vehicle for transporting heavy components of nuclear power plants. In this research, it was aimed at developing a vehicle which can carry heavy components and get over a step, climb and descend stairs, and run through a narrow passage having many curves as well as running on flat ground. For this purpose, the actual state of the transportation of heavy things was investigated during the regular inspection of a nuclear power station, and on the basis of this results, a prototype vehicle was made and tested. Thereafter, a transporting vehicle of actual scale was made and tested. The investigation of actual state and the examination of the fundamental concept, the design, trial manufacture and verifying test are reported. (Kako, I.)

Nuclear reactor fuel element splitter

International Nuclear Information System (INIS)

Yeo, D.

1976-01-01

A method and apparatus are disclosed for removing nuclear fuel from a clad fuel element. The fuel element is power driven past laser beams which simultaneously cut the cladding lengthwise into at least two longitudinal pieces. The axially cut lengths of cladding are then separated, causing the nuclear fuel contained therein to drop into a receptacle for later disposition. The cut lengths of cladding comprise nuclear waste which is disposed of in a suitable manner. 6 claims, 10 drawing figures

Heavy ion collisions with A = 1057: Aspects of nuclear stability and the nuclear equation of state in coalescing neutron-star binary systems

International Nuclear Information System (INIS)

Mathews, G.J.; Wilson, J.R.; Evans, C.R.; Detweiler, S.L.

1987-12-01

The dynamics of the final stages of the coalescence of two neturon stars (such as the binary pulsar PSR 1913+16) is an unsolved problem in astrophysics. Such systems are probably efficient generators of gravitational radiation, and may be significant contributors to heavy-element nucleosynthesis. The input physics for the study of such systems is similar to that required for the strudy of heavy-ion collision hydrodynamics; e.g., a finite temperature nuclear equation of state, properties of nuclei away from stability, etc. We discuss the development of a relativistic hydrodynamics code in three spatial dimensions for the purpose of studying such neutron-star systems. The properties of the mass-radius relation (determined by the nuclear equation of state) may lead to a proposed mechanism by which hot, highly neutronized matter is ejected from the coalescing stars. This material is photodisintegrated into a free (mostly) neutron gas which may subsequently experience rapid-neutron capture (r-process) nucleosynthesis. 15 refs., 4 figs

The origin of the chemical elements

International Nuclear Information System (INIS)

Tayler, R.J.

1984-01-01

The subject is discussed in relation to the composition of initially created matter and changes which have occurred during the life history of the universe, with particular reference to our galaxy and nearby galaxies. Headings are: observations of element abundances (stars, gas clouds in our own and nearby galaxies, hot gas in galaxy clusters, the solar system); the originally created matter (Big Bang theory and early nuclear reactions); processes changing observed composition (galactic evolution; nuclear fusion reactions in stellar interiors; chemical composition of a highly evolved massive star); supernovae (production of heavy elements); chemical evolution of the galaxy; production of very heavy elements (s process, r process). (U.K.)

Nuclear fuel elements

International Nuclear Information System (INIS)

Ainsworth, K.F.

1979-01-01

A nuclear fuel element is described having a cluster of nuclear fuel pins supported in parallel, spaced apart relationship by transverse cellular braces within coaxial, inner and outer sleeves, the inner sleeve being in at least two separate axial lengths, each of the transverse braces having a peripheral portion which is clamped peripherally between the ends of the axial lengths of the inner sleeve. (author)

Nuclear fuel element

International Nuclear Information System (INIS)

Grossman, L.N.; Levin, H.A.

1975-01-01

A nuclear fuel element has disposed therein an alloy having the essential components of nickel, titanium and zirconium, and the alloy reacts with water, water vapor and reactive gases at reactor ambient temperatures. The alloy is disposed in the plenum of the fuel element in the form of particles in a hollow gas permeable container having a multiplicity of openings of size smallr than the size of the particles. The container is preferably held in the spring in the plenum of the fuel element. (E.C.B.)

Embalse nuclear power plant and heavy water valuation

International Nuclear Information System (INIS)

Martin, Daniel E.

2008-01-01

The author describes the nuclear power plant characteristics, the building work, the heavy water valuation criteria and the reasons why he considers that any capital good can be valued by the cash-flow method. The Embalse nuclear power plant replacement value is of U$S 1.593.538.000. (author) [es

CARA Project: development of the advanced ULE fuel element for heavy water nuclear power plants

International Nuclear Information System (INIS)

Brasnarof, Daniel O.; Marino, Armando C.; Florido, Pablo C.; Munoz, C.; Bianchi, Daniel R.; Giorgis, Miguel A.

2006-01-01

The CARA Project (Spanish acronym of Combustible Avanzado para Reactores Argentinos) is a national fuel element technology development, compatible with our nuclear power plants (Atucha I, Embalse and Atucha II). It takes into account the experience obtained in our nuclear organisations (CNEA-CONUAR-NASA). The goal of the CARA fuel element is the performance improvement for those reactors and the enhancing of their normal operative conditions. The CARA design allows the burnup extension by using 52 rods of the same diameter. Likewise it keeps good thermo-hydraulic behaviour. The fuel bundle can be directly used in nuclear power plants with horizontal channels. By using an additional system it can be installed in the PHWR with vertical channels. The expected profits, by the use of the CARA in our reactors, broadly guaranty the recovery of the fund for its development, due to a reduction of the NPP fuels and back end cost. We estimate a reduction in the generation cost between 20 or 25 % in relation to the present one if we use 0.85 or 0.90% SEU (Slightly Enriched Uranium). The use of the CARA fuel in our reactors will also reduce the amount of spent fuel to be treated. The shortening could be between 17 to 27 % in Atucha I in relation to the present ULE (0.85%), between 38 to 46% for Embalse, and 45 to 53% for Atucha II. The mechanical behaviour and hydraulic compatibility have been verified. Several CARA prototypes were fabricated with a new design of the end plate and with new processes for the welding for the rods. We present in this paper the current status of the CARA fuel element development. (author) [es

Correlation of Heavy Element in Sea Water and Sediment Samples from Peninsula of Muria

International Nuclear Information System (INIS)

Rosidi; Sukirno

2007-01-01

The analysis of heavy metals in marine environmental samples peninsula of Muria in the year 2004 has been carried out by using neutron activation analysis (NAA) method. The objective of this analysis is to know the distribution of heavy metals in the sea water and sediment, which accommodate the recent environmental data in supporting the license of site for the nuclear power plants (NPP). The result of the analysis show that there were only 5 observed elements found in sea water and sediment were Cd, Co, Cr, Sb and Sc. All of heavy metals from sea water (0.002 mg/l) are obviously lower than the threshold value established by environmental minister Act; Kep LH No 51/2004. From the observed data to use software of SPSS version 10, application of the Pearson correlation (r) shows that between Co with Sc was indicator show a highly positive significant correlation (r=0.928), between Cr with Sc was sufficiently positive high (r=0.756), between Cr with Cd was precisely (r=0.611) while Co with Sb shows the significantly low (r=0.429). (author)

Nuclear research with heavy ions. Annual progress report, January 1, 1981-December 31, 1981

International Nuclear Information System (INIS)

Kaplan, M.

1981-11-01

The experimental research program is primarily concerned with the nuclear reactions induced by collisions between heavy-ion projectiles and complex target nuclei, the dynamics and thermodynamics associated with such collisions, and the relationships of the observables to the equilibrium and non-equilibrium properties of nuclear matter. As a sensitive probe of the nuclear interactions, detailed measurements of light-charged-particle emission were performed using counter telescopes for atomic number and mass number identification. Preliminary results from a new experiment on direct and evaporation-like emission of 4 He from reactions of 340-MeV 40 Ar with 238 U are reported. Using a large two-dimensional position-sensitive avalanche detector, and measuring three-fold coincidence events between two fission fragments and an emitted 4 He particle, we were able to distinguish emission processes in fusion-like fission from those associated with inelastic reactions. Analysis of the data shows isotropic and strongly forward-peaked 4 He components for both fusion and sequential fission, and kinematic evidence indicates substantial evaporation-like emission from the composite system rather than from fission fragments. The effects of light element impurities on charged particle spectra from heavy ion collisions are discussed, and a technique for directly evaluating the impurity contribution is briefly described

Glenn T. Seaborg and heavy ion nuclear science

International Nuclear Information System (INIS)

Loveland, W.

1992-04-01

Radiochemistry has played a limited but important role in the study of nucleus-nucleus collisions. Many of the important radiochemical studies have taken place in Seaborg's laboratory or in the laboratories of others who have spent time in Berkeley working with Glenn T. Seaborg. I will discuss studies of low energy deep inelastic reactions with special emphasis on charge equilibration, studies of the properties of heavy residues in intermediate energy nuclear collisions and studies of target fragmentation in relativistic and ultrarelativistic reactions. The emphasis will be on the unique information afforded by radiochemistry and the physical insight derived from radiochemical studies. Future roles of radiochemistry in heavy ion nuclear science also will be discussed

Nuclear fuel elements design, fabrication and performance

CERN Document Server

Frost, Brian R T

1982-01-01

Nuclear Fuel Elements: Design, Fabrication and Performance is concerned with the design, fabrication, and performance of nuclear fuel elements, with emphasis on fast reactor fuel elements. Topics range from fuel types and the irradiation behavior of fuels to cladding and duct materials, fuel element design and modeling, fuel element performance testing and qualification, and the performance of water reactor fuels. Fast reactor fuel elements, research and test reactor fuel elements, and unconventional fuel elements are also covered. This volume consists of 12 chapters and begins with an overvie

Review of even element super-heavy nuclei and search for element 120

Energy Technology Data Exchange (ETDEWEB)

Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Maurer, J.; Barth, W.; Burkhard, H.G.; Dahl, L.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Runke, J.; Scheidenberger, C.; Schoett, H.J.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Muenzenberg, G. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Manipal University, Manipal Centre for Natural Sciences, Manipal, Karnataka (India); Antalic, S.; Saro, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Grzywacz, R. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States); Hamilton, J.H. [Vanderbuilt University, Department of Physics and Astronomy, Nashville, TN (United States); Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Shaughnessy, D.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Miernik, K. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); University of Warsaw, Warsaw (Poland); Miller, D. [University of Tennessee, Knoxville, TN (United States); Morita, K. [RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Roberto, J.B.; Rykaczewski, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland)

2016-06-15

The reaction {sup 54}Cr + {sup 248}Cm was investigated at the velocity filter SHIP at GSI, Darmstadt, with the intention to study production and decay properties of isotopes of element 120. Three correlated signals were measured, which occurred within a period of 279ms. The heights of the signals correspond with the expectations for a decay sequence starting with an isotope of element 120. However, a complete decay chain cannot be established, since a signal from the implantation of the evaporation residue cannot be identified unambiguously. Measured properties of the event chain are discussed in detail. The result is compared with theoretical predictions. Previously measured decay properties of even element super-heavy nuclei were compiled in order to find arguments for an assignment from the systematics of experimental data. In the course of this review, a few tentatively assigned data could be corrected. New interpretations are given for results which could not be assigned definitely in previous studies. The discussion revealed that the cross-section for production of element 120 could be high enough so that a successful experiment seems possible with presently available techniques. However, a continuation of the experiment at SHIP for a necessary confirmation of the results obtained in a relatively short irradiation of five weeks is not possible at GSI presently. Therefore, we decided to publish the results of the measurement and of the review as they exist now. In the summary and outlook section we also present concepts for the continuation of research in the field of super-heavy nuclei. (orig.)

Nuclear research with heavy ions

International Nuclear Information System (INIS)

Kaplan, M.

1991-08-01

This report discusses the following topics: Asymmetric fission of 149 Tb* from the finite-range, rotating-liquid-drop model: mean total kinetic energies for binary fragmentation; charged-particle evaporation from hot composite nuclei: evidence over a broad Z range for distortions from cold nuclear profiles; the role of reversed kinematics and double kinematic solutions in nuclear reactions studies; production of intermediate-mass-fragments in the reaction 98 Mo + 51 V at an excitation energy E* = 224-MeV; emission of light charged particles in the reaction 344-MeV 28 Si + 121 Sb; continued developments of the statistical evaporation code LILITA N90; and planning for heavy-ion-collision studies at very high energies: the STAR collaboration at RHIC

Heavy water radiolysis and chemistry control of the Fugen Nuclear Power Station

International Nuclear Information System (INIS)

Ibuki, Y.; Kitabata, T.; Kato, T.

1989-01-01

A computer analysis for heavy water radiolysis clarified the mechanism of the heavy water radiolysis rate change with impurities in the heavy water and cover gas, helium. The mechanism is supported by over ten years' operational data of the heavy water radiolysis in the Fugen nuclear power station. (author)

Probing the nuclear symmetry energy with heavy-ion collisions

Directory of Open Access Journals (Sweden)

De Filippo E.

2015-01-01

Full Text Available Heavy ion collisions (HIC have been widely used to extract the parametrization of symmetry energy term of nuclear equation of state as a function of barionic density. HIC in fact are a unique tool in terrestrial laboratories to explore the symmetry energy around the saturation density (ρ0 = 0.16fm−3 from sub-saturation densities (Fermi energies towards compressed nuclear matter (ρ > 2 − 3ρ0 that can be reached at relativistic energies, as a function of different conditions of temperature, mass asymmetry and isospin. One of the main study at present is to reach a coherent description of EOS of asymmetric nuclear matter from heavy ion collisions of stable and exotic nuclei, nuclear structure studies and astrophysical observations. In this work an overview of the current status of the research is shortly reviewed together with new perspectives aimed to reduce the present experimental and theoretical uncertainties.

Theory of nuclear excitation by electron capture for heavy ions

Energy Technology Data Exchange (ETDEWEB)

Gagyi-Palffy, A.

2006-07-01

The resonant process of nuclear excitation by electron capture (NEEC) in collisions involving highly-charged ions has been investigated theoretically. NEEC is a rare recombination process in which a free electron is captured into a bound shell of an ion with the simultaneous excitation of the nucleus. Total cross sections for NEEC followed by the radiative decay of the excited nucleus are presented for various collision systems. The possibility to observe the NEEC in scattering experiments with trapped or stored ions was discussed focusing on the cases with the largest calculated resonance strength. As the photons emitted in different channels of the electron recombination process are indistinguishable in the total cross section, the interference between NEEC followed by the radiative decay of the nucleus and radiative recombination was investigated. The angular distribution of the emitted photons in the recombination process provides means to discern the two processes. Angular differential cross sections for the emitted photons in the case of E2 nuclear transitions were presented for several heavy elements. (orig.)

Study of nuclear reactions involving heavy nuclei and intermediate- and high-energy protons and an application in nuclear reactor physics (ADS)

International Nuclear Information System (INIS)

Matuoka, Paula Fernanda Toledo

2016-01-01

In the present work, intermediate- and high-energy nuclear reactions involving heavy nuclei and protons were studied with the Monte Carlo CRISP (Rio - Ilheus - Sao Paulo Collaboration) model. The most relevant nuclear processes studied were intranuclear cascade and fission-evaporation competition. Preliminary studies showed fair agreement between CRISP model calculation and experimental data of multiplicity of evaporated neutrons (E 20 MeV) were emitted mostly in the intranuclear cascade stage, while evaporation presented larger neutron multiplicity. Fission cross section of 209 mb and spallation cross section of 1788 mb were calculated { both in agreement with experimental data. The fission process resulted in a symmetric mass distribution. Another Monte Carlo code, MCNP, was used for radiation transport in order to understand the role of a spallation neutron source in a ADS (Accelerator Driven System) nuclear reactor. Initially, a PWR reactor was simulated to study the isotopic compositions in spent nuclear fuel. As a rst attempt, a spallation neutron source was adapted to an industrial size nuclear reactor. The results showed no evidence of incineration of transuranic elements and modifications were suggested. (author)

MEGHNAD – A multi element detector array for heavy ion collision ...

Indian Academy of Sciences (India)

When heavy ion beam available from such machines fall on a target and undergo collision, very rich and often pristine fields of research open up. In order to carry on such activities, we have taken up a project to build a multi element gamma, heavy ion and neutron array of detectors (MEGHNAD) to detect and study the ...

Contribution of Heavy Water Board in nuclear fuel cycle technologies. Contributed Paper IT-03

International Nuclear Information System (INIS)

Mohanty, P.R.

2014-01-01

The three stage Indian nuclear power programme envisages use of closed nuclear fuel cycle and thorium utilization as its mainstay for long term energy security on sustainable basis. India is committed to realize this objective through the development and deployment of frontier technologies pertaining to all aspects of a closed nuclear fuel cycle. Comprehensive indigenous capabilities have been developed in all aspects of nuclear power and associated fuel cycles. Heavy Water Board (HWB), with its abiding objective of fulfilling demand of heavy water for India's flourishing nuclear power program, is one of the frontrunner in Nuclear Fuel Cycle Technology. HWB is now engaged in wide spectrum of activities in various facets of fuel cycle covering all the three stages of Indian Nuclear Power Programme. HWB is contributing to Nuclear Fuel Cycle through large scale production and sustained supply of key input materials including heavy water, solvents for nuclear hydrometallurgy, 10 B enriched boron etc

Status on the heavy elements research using the DV-DFS method

International Nuclear Information System (INIS)

Hirata, Masaru; Bastug, T.; Sekine, Rika; Onoe, Jun; Nakamatsu, Hirohide; Mukoyama, Takeshi

1999-03-01

In this review report, we describe recent progress on the heavy elements research using the discrete-variational Dirac-Fock-Slater (DV-DFS) method which is being improved by Kyoto University, Shizuoka University, RIKEN and JAERI. The DV-DFS is a versatile method for interpreting spectroscopic data and predicting chemical bonding of polyatomic systems including heavy elements. This review is based on the lectures given in 74th spring meeting of chemical Society of Japan (March, 1998) and also at the workshop on the XAFS-relativistic electronic structure calculation for the actinides research which was held at Tokai Research Establishment of JAERI (November, 1998). (author)

Procedure for operating a heavy water cooled power reactor

International Nuclear Information System (INIS)

Rau, P.; Kumpf, H.

1981-01-01

Nuclear reactors cooled by heavy water usually have equipment for fuel element exchange during operation, with the primary circuit remaining contained. This fuel element exchange equipment is expensive and complicated in many respects. According to the invention, the heavy water is therefore replaced by light water after a certain time of operation in such way that light water is led in and heavy water is led off. After the replacement, at least a quarter of the fuel elements of the reactor core is exchanged with the reactor pressure vessel being open. Then the light water serving as a shielding is replaced by heavy water, with the reactor pressure vessel being closed. The invention is of interest particularly for high-conversion reactors. (orig.) [de

Nonlinear finite element analysis of nuclear reinforced prestressed concrete containments up to ultimate load capacity

International Nuclear Information System (INIS)

Gupta, A.; Singh, R.K.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

1996-01-01

For safety evaluation of nuclear structures a finite element code ULCA (Ultimate Load Capacity Assessment) has been developed. Eight/nine noded isoparametric quadrilateral plate/shell element with reinforcement as a through thickness discrete but integral smeared layer of the element is presented to analyze reinforced and prestressed concrete structures. Various constitutive models such as crushing, cracking in tension, tension stiffening and rebar yielding are studied and effect of these parameters on the reserve strength of structures is brought out through a number of benchmark tests. A global model is used to analyze the prestressed concrete containment wall of a typical 220 MWe Pressurized Heavy Water Reactor (PHWR) up to its ultimate capacity. This demonstrates the adequacy of Indian PHWR containment design to withstand severe accident loads

Influence of the nuclear autocorrelation function on the positron production in heavy-ion collisions

International Nuclear Information System (INIS)

Tomoda, T.; Weidenmueller, H.A.

1983-01-01

The influence of a nuclear reaction on atomic positron production in heavy-ion collisions is investigated. Using statistical concepts, we describe the nuclear S matrix for a heavy-ion induced reaction as a statistically fluctuating function of energy. The positron production rate is then dependent on the autocorrelation function of this S matrix, and on the ratio of the ''direct'' versus the ''fluctuating'' part of the nuclear cross section. Numerical calculations show that in this way, current experimental results on positron production in heavy-ion collisions can be reproduced in a semiquantitative fashion

Nuclear reactor theory

International Nuclear Information System (INIS)

Sekimoto, Hiroshi

2007-09-01

This textbook is composed of two parts. Part 1 'Elements of Nuclear Reactor Theory' is composed of only elements but the main resource for the lecture of nuclear reactor theory, and should be studied as common knowledge. Much space is therefore devoted to the history of nuclear energy production and to nuclear physics, and the material focuses on the principles of energy production in nuclear reactors. However, considering the heavy workload of students, these subjects are presented concisely, allowing students to read quickly through this textbook. (J.P.N.)

Heavy element accumulation in Evernia prunastri lichen transplants around a municipal solid waste landfill in central Italy.

Science.gov (United States)

Nannoni, Francesco; Santolini, Riccardo; Protano, Giuseppe

2015-09-01

This paper presents the results of a biomonitoring study to evaluate the environmental impact of airborne emissions from a municipal solid waste landfill in central Italy. Concentrations of 11 heavy elements, as well as photosynthetic efficiency and cell membrane integrity were measured in Evernia prunastri lichens transplanted for 4months in 17 monitoring sites around the waste landfill. Heavy element contents were also determined in surface soils. Analytical data indicated that emissions from the landfill affected Cd, Co, Cr, Cu, Ni, Pb, Sb and Zn concentrations in lichens transplanted within the landfill and along the fallout direction. In these sites moderate to severe accumulation of these heavy elements in lichens was coupled with an increase in cell membrane damage and decrease in photosynthetic efficiency. Nevertheless, results indicated that landfill emissions had no relevant impact on lichens, as heavy element accumulation and weak stress symptoms were detected only in lichen transplants from sites close to solid waste. The appropriate management of this landfill poses a low risk of environmental contamination by heavy elements. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental investigation in separating the heavy metal elements of refuse incineration fly ashes by using molten iron

Energy Technology Data Exchange (ETDEWEB)

Yang, J. [Chongqing Univ., Chongqing (China)]|[CPI-Yuanda Environmental-protection Engineering Co. Ltd., Chongqing (China); Liu, Q.; Dong, L. [Chongqing Univ., Chongqing (China); Du, Y. [CPI-Yuanda Environmental-protection Engineering Co. Ltd., Chongqing (China)

2008-07-01

One of the main waste treatment methods in the world for municipal solid waste (MSW) is incineration. It is effective in toxic substance destruction, waste volume reduction, and energy recovery. Some chemical substances are accumulated during incineration, most notably lead, zinc, chromium and cadmium, as well as other heavy metals. Untreated fly ash disposed in landfills can pollute the soil, surface water and groundwater because of the high levels of hazardous heavy metals and high salt concentration that can be leached out. This paper presented an experiment that melt-separated the heavy metal elements from fly ash generated during refuse incineration. Molted iron, was used as resolvent to dissolve the heavy metal elements in it. The paper described the materials and methods as well as the results of the study. It was concluded that using molted iron to separate the heavy metal elements from MSW incineration fly ash was feasible. The removal ratio of the main heavy metal elements was above 80 per cent, and some of it was above 99 per cent. 5 refs., 7 tabs., 1 fig.

What can we learn from the fission time of the super-heavy elements?

OpenAIRE

Boilley, D.; Marchix, A.; Wilgenbus, D.; Lallouet, Y.; Gimbert, F.; Abe, Y.

2007-01-01

International audience; Recent experiments performed at GANIL with a crystal blocking technique have shown direct evidences of long fission times in the Super-Heavy Elements (SHE) region. Aimed to localize the SHE island of stability, can these experiments give access to the fission barrier and then to the shell-correction energy? In this paper, we calculate the fission time of heavy elements by using a new code, KEWPIE2, devoted to the study of the SHE.We also investigate the effect of poten...

EDRXF measurements of heavy elements in soil samples from some potentially polluted sites in zambia

International Nuclear Information System (INIS)

Hayumbu, P.; Phiri, L.K.; Mambo, A.; Sokotela, S.B.

2001-01-01

A survey of heavy element levels in top soils collected around four industrial plants and along four highway stretches demonstrated that there was significant pollution only around an abandoned Pb/Zn mine. Sample collection in a rectangular grid encompassing each source sought to depict the spatial extent of pollution. Ascertaining levels of heavy elements in potentially polluted soils in urban areas of Zambia and along major highways was deemed desirable because it is common practice to grow maize and vegetables in lots adjacent to accessible industrial sites and highways. Pb is a heavy element of interest for all sampled sites whose distribution at the abandoned mine ranged from 13 to 2028 ppm

Double Beta Decay and Neutrino Masses Accuracy of the Nuclear Matrix Elements

International Nuclear Information System (INIS)

Faessler, Amand

2005-01-01

The neutrinoless double beta decay is forbidden in the standard model of the electroweak and strong interaction but allowed in most Grand Unified Theories (GUT's). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass, the neutrinoless double beta decay is allowed. Apart of one claim that the neutrinoless double beta decay in 76 Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUT's and the minimal R-parity violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUT's. For that one has to assume that the specific mechanism is the leading one for the neutrinoless double beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present contribution, one discusses the accuracy of the present status of calculating the nuclear matrix elements and the corresponding limits of GUT's and supersymmetric parameters

Matrix elements of Δ B =0 operators in heavy hadron chiral perturbation theory

Science.gov (United States)

Lee, Jong-Wan

2015-05-01

We study the light-quark mass and spatial volume dependence of the matrix elements of Δ B =0 four-quark operators relevant for the determination of Vu b and the lifetime ratios of single-b hadrons. To this end, one-loop diagrams are computed in the framework of heavy hadron chiral perturbation theory with partially quenched formalism for three light-quark flavors in the isospin limit; flavor-connected and -disconnected diagrams are carefully analyzed. These calculations include the leading light-quark flavor and heavy-quark spin symmetry breaking effects in the heavy hadron spectrum. Our results can be used in the chiral extrapolation of lattice calculations of the matrix elements to the physical light-quark masses and to infinite volume. To provide insight on such chiral extrapolation, we evaluate the one-loop contributions to the matrix elements containing external Bd, Bs mesons and Λb baryon in the QCD limit, where sea and valence quark masses become equal. In particular, we find that the matrix elements of the λ3 flavor-octet operators with an external Bd meson receive the contributions solely from connected diagrams in which current lattice techniques are capable of precise determination of the matrix elements. Finite volume effects are at most a few percent for typical lattice sizes and pion masses.

Improved nuclear fuel element

International Nuclear Information System (INIS)

1980-01-01

The invention is of a nuclear fuel element which comprises a central core of a body of nuclear fuel material selected from the group consisting of compounds of uranium, plutonium, thorium and mixtures thereof, and an elongated composite cladding container comprising a zirconium alloy tube containing constituents other than zirconium in an amount greater than about 5000 parts per million by weight and an undeformed metal barrier of moderate purity zirconium bonded to the inside surface of the alloy tube. The container encloses the core so as to leave a gap between the container and the core during use in a nuclear reactor. The metal barrier is of moderate purity zirconium with an impurity level on a weight basis of at least 1000ppm and less than 5000ppm. Impurity levels of specific elements are given. Variations of the invention are also specified. The composite cladding reduces chemical interaction, minimizes localized stress and strain corrosion and reduces the likelihood of a splitting failure in the zirconium alloy tube. Other benefits are claimed. (U.K.)

Nuclear reactor fuel elements

International Nuclear Information System (INIS)

Hindle, E.D.

1984-01-01

The fuel elements for a pressurised water reactor comprise arrays of rods of zirconium alloy sheathed nuclear fuel pellets. The helium gas pressure within each rod differs substantially from that of its closest neighbours

Improved nuclear fuel element

International Nuclear Information System (INIS)

Klepfer, H.H.

1974-01-01

A nuclear fuel element is described which comprises: 1) an elongated clad container, 2) a layer of high lubricity material being disposed in and adjacent to the clad container, 3) a low neutron capture cross section metal liner being disposed in the clad container and adjacent to the layer, 4) a central core of a body of nuclear fuel material disposed in and partially filling the container and forming an internal cavity in the container, 5) an enclosure integrally secured and sealed at each end of the container, and a nuclear fuel material retaining means positioned in the cavity. (author)

A study of pollution extent in some drinking water resources by heavy elements in Hadramout governorate

International Nuclear Information System (INIS)

Barheyan, Saad Awadh

2001-01-01

The paper is considered as a preliminary study of pollution extent in some drinking water resources in Hadramout governorate by heavy elements which differ in their toxicity. The elements subjected to study are Cd, Pb, Fe, Cr, Mn, Zn, Co and Cu. Atomic absorption spectrometric method of analysis (AAS) is used for the determination of heavy elements concentrations. The elemental analysis of drinking water samples shows that the concentration of the above-mentioned elements in drinking water resources, lies in the permissible limit given by the WHO. Similarity of elements content is observed in Thela and Fuwah waters, bu the case is different for Ghail Bawzeer and Asshihir waters due to their different lithospheric structures. Drinking water used by the civilians is not subjected to physical, biological or chemical treatment which may lead to total or partial removal of heavy elements and other rejected impurities. Drinking water running in distribution nets is a hard water and has a weak base (Ph which explains the reason why heavy elements are absorbed and precipitated inside drinking water pipes before they reach consumers. This type of hard water causes accumulation of salt precipitates inside the water pipes which results in many economic and health disturbances to consumers. The slight increase of Cr, Mn, and Co concentration in drinking water flowing in the pipes may be due to the effect of some anions such as nitrates which form soluble compounds with the elements contained in the chemical composition of the drinking water pipes. This paper is a strong indicator for determination of heavy elements concentrations in different drinking water resources in Hadramout govemorate. Such approach seeks a further comprehensive work with special focus on the study of lithospheric structure of the feeding water regions of Hadramout aquifers. (author)

Exclusion of nuclear forces in heavy-ion Coulomb excitation and Coulomb fission experiments

International Nuclear Information System (INIS)

Neese, R.E.; Guidry, M.W.

1982-01-01

A simple prescription for estimating the energy at which nuclear forces begin to play a role in heavy-ion Coulomb excitation and Coulomb fission experiments is presented. The method differs from most commonly used recipes in accounting for projectile and target nucleus deformation effects. Using a single adjustable parameter the formula reproduces the energy for the onset of Coulomb-nuclear interference effects for a broad range of heavy-ion systems. It is suggested that most Coulomb fission experiments which have been done involve both Coulomb and nuclear excitation processes and should more properly be termed Coulomb-nuclear fission experiments

Nuclear physics and heavy element research at Lawrence Livermore National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Stoyer, Mark A; Ahle, L E; Becker, J A; Bernshein, L A; Bleuel, D L; Burke, J T; Dashdorj, D; Henderson, R A; Hurst, A M; Kenneally, Jacqueline M; Lesher, S R; Moody, K J; Nelson, S L; Norman, E B; Pedretti, M; Scielzo, N D; Shaughnessy, D A; Sheets, S A; Stoeffl, W; Stoyer, N J [Lawrence Livermore National Laboratory, University of California, Livermore (United States)

2009-12-31

This paper highlights some of the current basic nuclear physics research at Lawrence Livermore National Laboratory (LLNL). The work at LLNL concentrates on investigating nuclei at the extremes. The Experimental Nuclear Physics Group performs research to improve our understanding of nuclei, nuclear reactions, nuclear decay processes and nuclear astrophysics; an expertise utilized for important laboratory national security programs and for world-class peer-reviewed basic research.

On the domestically-made heavy forging for reactor pressure vessels of PWR nuclear power plant

International Nuclear Information System (INIS)

Pan Xiren; Zhang Chen.

1988-01-01

The present situation of the foreign heavy forgings for nuclear reactor pressure vessels and the heavy forgings condition which is used for the Qinshan 300MWe nuclear power plant are described. Some opinions of domestic products is proposed

Nuclear structure effects in quasifission – understanding the formation of the heaviest elements

Directory of Open Access Journals (Sweden)

Hinde D. J.

2016-01-01

Full Text Available Quasifission is an important process suppressing the fusion of two heavy nuclei in reactions used to create superheavy elements. Quasifission results in rapid separation of the dinuclear system initially formed at contact. Achieving reliable a priori prediction of quasifission probabilities is a very diffcult problem. Through measurements with projectiles from C to Ni, the Australian National University’s Heavy Ion Accelerator Facility and CUBE spectrometer have been used to map out mass-angle distributions (MAD - the fission mass-ratio as a function of centre-of-mass angle. These provide information on quasifission dynamics in the least modeldependent way. Average quasifission time-scales have been extracted, and compared with TDHF calculations of the collisions, with good agreement being found. With the baseline information from the survey of experimental MAD, strong influences of the nuclear structure of the projectile and target nuclei can be clearly determined.

Rack for nuclear fuel elements

International Nuclear Information System (INIS)

Rubinstein, H.J.; Gordon, C.B.; Robison, A.; Clark, P.M.

1977-01-01

Disclosed is a rack for storing spent nuclear fuel elements in which a plurality of aligned rows of upright enclosures of generally square cross-sectional areas contain vertically disposed spent fuel elements. Each fuel element is supported at the lower end thereof by a respective support that rests on the floor of the spent fuel pool for a nuclear power plant. An open rack frame is employed as an upright support for the enclosures containing the spent fuel elements. Legs at the lower corners of the frame rest on the floor of the pool to support the frame. In one exemplary embodiment, the support for the fuel element is in the form of a base on which a fuel element rests and the base is supported by legs. In another exemplary embodiment, each fuel element is supported on the pool floor by a self-adjusting support in the form of a base on which a fuel element rests and the base rests on a ball or swivel joint for self-alignment. The lower four corners of the frame are supported by legs adjustable in height for leveling the frame. Each adjustable frame leg is in the form of a base resting on the pool floor and the base supports a threaded post. The threaded post adjustably engages a threaded column on which rests the lower end of the frame. 16 claims, 14 figures

Production of heavy nuclides in nuclear devices

Energy Technology Data Exchange (ETDEWEB)

Eccles, Samuel F [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1970-05-15

Since the last Plowshare Symposium in 1964 a number of experiments have been carried out to study the production of heavy nuclei by rapid multiple neutron capture in specially designed nuclear devices. These experiments listed below were conducted underground at the Nevada Test Site and data were obtained radiochemically after sample recovery by drillback. The main characteristics of these experiments are 1) higher neutron fluxes than in the early events, 2) a variety of targets, including 238-U, 242-Pu, 237-Np, 243-Am, 232-Th, 3) the occurrence of an interesting 'reversal of the odd-even effect' in the mass yield curves, and 4) the absence of nuclei in the debris with (Z,A) greater than (100,257). Analysis of data from these experiments have led to capture cross sections for neutron-rich uranium isotopes (out to 249-U), and capture-to-fission ratios for the odd-A neutron-rich plutonium isotopes (out to 253-Pu). General studies of the fission process in neutron-rich nuclei have also been undertaken using the data from these experiments. The large amounts of 250Cm and 257Fm made in the recent Hutch experiment ({approx}1 x 10{sup 20} and {approx}5 x 10{sup 17} atoms, respectively) make it scientifically exciting, and economically feasible, to mine and recover enough material to produce laboratory targets of these isotopes. These targets would be used in investigations of yet-undiscovered, short-lived isotopes of Fm, Md, and No, as well as the possible production of new isotopes of element 104 and even element 105. (author)

Production of heavy nuclides in nuclear devices

International Nuclear Information System (INIS)

Eccles, Samuel F.

1970-01-01

Since the last Plowshare Symposium in 1964 a number of experiments have been carried out to study the production of heavy nuclei by rapid multiple neutron capture in specially designed nuclear devices. These experiments listed below were conducted underground at the Nevada Test Site and data were obtained radiochemically after sample recovery by drillback. The main characteristics of these experiments are 1) higher neutron fluxes than in the early events, 2) a variety of targets, including 238-U, 242-Pu, 237-Np, 243-Am, 232-Th, 3) the occurrence of an interesting 'reversal of the odd-even effect' in the mass yield curves, and 4) the absence of nuclei in the debris with (Z,A) greater than (100,257). Analysis of data from these experiments have led to capture cross sections for neutron-rich uranium isotopes (out to 249-U), and capture-to-fission ratios for the odd-A neutron-rich plutonium isotopes (out to 253-Pu). General studies of the fission process in neutron-rich nuclei have also been undertaken using the data from these experiments. The large amounts of 250Cm and 257Fm made in the recent Hutch experiment (∼1 x 10 20 and ∼5 x 10 17 atoms, respectively) make it scientifically exciting, and economically feasible, to mine and recover enough material to produce laboratory targets of these isotopes. These targets would be used in investigations of yet-undiscovered, short-lived isotopes of Fm, Md, and No, as well as the possible production of new isotopes of element 104 and even element 105. (author)

Valuation of Embalse Nuclear Power Plant and of heavy water

International Nuclear Information System (INIS)

Martin, D.E.

2008-01-01

The author describes the Nuclear Power Plant characteristics, the building work, the heavy water valuation criteria and the reasons why he considers that any capital good can be valuated by means of cash-flow. The value of replacement of Embalse Nuclear Power Plant is of U$S 1.593.538.000 (authors) [es

CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

Energy Technology Data Exchange (ETDEWEB)

Weberg, Micah J. [PhD Candidate in Space Science, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2134A Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Lepri, Susan T. [Associate Professor, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2429 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States); Zurbuchen, Thomas H., E-mail: mjweberg@umich.edu, E-mail: slepri@umich.edu, E-mail: thomasz@umich.edu [Professor, Space Science and Aerospace Engineering, Associate Dean for Entrepreneurship Senior Counselor of Entrepreneurship Education, Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, 2431 Space Research Building, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA. (United States)

2015-03-10

The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space.

CORONAL SOURCES, ELEMENTAL FRACTIONATION, AND RELEASE MECHANISMS OF HEAVY ION DROPOUTS IN THE SOLAR WIND

International Nuclear Information System (INIS)

Weberg, Micah J.; Lepri, Susan T.; Zurbuchen, Thomas H.

2015-01-01

The elemental abundances of heavy ions (masses larger than He) in the solar wind provide information about physical processes occurring in the corona. Additionally, the charge state distributions of these heavy ions are sensitive to the temperature profiles of their respective source regions in the corona. Heavy ion dropouts are a relatively new class of solar wind events identified by both elemental and ionic charge state distributions. We have shown that their origins lie in large, closed coronal loops where processes such as gravitational settling dominate and can cause a mass-dependent fractionation pattern. In this study we consider and attempt to answer three fundamental questions concerning heavy ion dropouts: (1) 'where are the source loops located in the large-scale corona?'; (2) 'how does the interplay between coronal processes influence the end elemental abundances?'; and (3) 'what are the most probable release mechanisms'? We begin by analyzing the temporal and spatial variability of heavy ion dropouts and their correlation with heliospheric plasma and magnetic structures. Next we investigate the ordering of the elements inside dropouts with respect to mass, ionic charge state, and first ionization potential. Finally, we discuss these results in the context of the prevailing solar wind theories and the processes they posit that may be responsible for the release of coronal plasma into interplanetary space

Nuclear reactor fuel elements

International Nuclear Information System (INIS)

Hindle, E.D.

1981-01-01

An array of rods comprising zirconium alloy sheathed nuclear fuel pellets assembled to form a fuel element for a pressurised water reactor is claimed. The helium gas pressure within each rod differs substantially from that of its closest neighbours

Nuclear responses in INTOR plasma stabilization elements

International Nuclear Information System (INIS)

Gohar, Y.; Gilligan, J.; Jung, J.; Mattas, R.F.; Miley, G.H.; Wiffen, F.W.; Yang, S.

1985-01-01

Nuclear responses in the plasma stabilization elements were studied in a parametric fashion as a part of the transient electromagnetics critical issue C of ETR/INTOR activity. The main responses are neutron fluence and radiation dose in the insulator material, induced resistivity and atomic displacement in the conductor material, nuclear heating and life analysis for the elements. Copper and aluminum conductors with either MgAl 2 O 4 or MgO insulating material were investigated. Radiation damage and life analysis for these elements were also discussed

Nuclear Fragmentation in Clinical Heavy Ion Beams, Should We Worry?

DEFF Research Database (Denmark)

Bassler, Niels; Hansen, David Christoffer; Toftegaard, Jakob

2012-01-01

Particle therapy with fast ions is increasingly applied as a treatment option for localized inoperable tumour sites. One of the reasons for the increased complications of understanding heavy ion dosimetry and radiobiology stems from the mixed particle spectrum which occurs due to nuclear fragment......Particle therapy with fast ions is increasingly applied as a treatment option for localized inoperable tumour sites. One of the reasons for the increased complications of understanding heavy ion dosimetry and radiobiology stems from the mixed particle spectrum which occurs due to nuclear....... The concept of relative biological effectiveness (RBE) translates the physical dose to a biological effective dose which is iso-effective to photon radiation. Radiobiological models based on amorphous track structure such as the Local Effect Model, but also microdosimetry based models both rely on a full...... the sensitivity on the three fields mentioned above, including: turning off nuclear fragmentation entirely, changing all ineleastic cross sections +/- 20%, changing key parameters in the Fermi-Breakup (FB) model. Results show nuclear effects have their largest impact on the dose distribution. Stopping power...

Heavy element affinities in Apollo 17 samples

International Nuclear Information System (INIS)

Allen, R.O. Jr.; Jovanovic, S.; Reed, G.W. Jr.

1975-01-01

204 Pb, Bi, Tl and Zn in samples from Apollo 17 exhibit relationships not found in samples from other sites. 204 Pb, Tl and Zn in residues remaining after dilute acid leaching are correlated with one another. Orange soil 74220, which is enriched in 204 Pb, Tl and Zn, is included in these relationships. In addition the submicron metallic phase generally associated with agglutinate formation is correlated with all three of these elements; this relationship has already been reported for 204 Pb in other samples. Thus, orange soil and agglutinates appear to be involved in concentrating heavy volatile metals. A process other than mixing is required to account for this. As a consequence of the isolation of the landing site by the surrounding massifs, local supply and recycling of volatile trace elements in soils may account for some of the interelement relations. (Auth.)

Heavy flavor operator matrix elements at O({alpha}{sub s}{sup 3})

Energy Technology Data Exchange (ETDEWEB)

Bierenbaum, Isabella; Buemlein, Johannes; Klein, Sebastian

2008-12-15

The heavy quark effects in deep.inelastic scattering in the asymptotic regime Q{sup 2}>>m{sup 2} can be described by heavy flavor operator matrix elements. Complete analytic expressions for these objects are currently known to NLO. We present first results for fixed moments at NNLO. This involves a recalculation of fixed moments of the corresponding NNLO anomalous dimensions, which we thereby confirm. (orig.)

Non destructive SXRF analysis of heavy elements in lichens

International Nuclear Information System (INIS)

Ramos, M.T.; Figueiredo, M.O.; Pereira da Silva, T.; Basto, M.J.; Chevallier, P.

2000-01-01

Various species incrusting granitic and calcareous rocks were collected at different places covering a large span of atmospheric conditions. They were chemically studied by synchrotron- induced X-ray fluorescence (SXRF), a nondestructive technique of outmost importance in the field, allowing for a future use of the same lichen fragments in further tests. This study proved that lichens - at least the saxicolous species - concentrate heavy elements recognized as strong pollutants, like lead and bromine, irrespective the environmental availability of these elements, either in the atmosphere or in the rock substrate, partially frustrating the use of saxicolous lichens as pollution monitors. (author)

The heavy-ion total reaction cross-section and nuclear transparancy

International Nuclear Information System (INIS)

Rego, R.A.; Hussein, M.S.

1982-10-01

The total reaction cross section of heavy ions at intermediate energies is discussed. The special role played by the individual nucleon-nucleon collisions in determining the nuclear transparancy is analysed. Several competing effects arising from the nuclear and Coulomb interactions between the two ions are found to be important in determing σ sub(R) at lower energies. (Author) [pt

The heavy-ion total reaction cross-section and nuclear transparency

International Nuclear Information System (INIS)

Rego, R.A.; Hussein, M.S.

1982-01-01

The total reaction cross section of heavy ions at intermediate energies is discussed. The special role played by the individual nucleon-nucleon collisions in determining the nuclear transparency is analysed. Several competing effects arising from the nuclear and Coulomb interactions between the two ions are found to be important in determining σ(sub R) at lower energies. (Author) [pt

Application of insoluble tannin to recovery of uranium, TRU and heavy metals elements form radioactive liquid waste

International Nuclear Information System (INIS)

Hamaguchi, Kazuhiko; Shirato, Wataru; Nakamura, Yasuo; Matsumura, Tatsuro; Takeshita, Kenji; Nakano, Yoshio

1999-01-01

Mitsubishi Nuclear Fuel Co., Ltd. (MNF) has developed a new adsorbent, TANNIX (tread mark), for the recovery of uranium, TRU and heavy metal elements in the liquid waste, in which TANNIX derived from a natural tannin polymer. TANNIX has same advantages that handling is easier than that of standard IX-resin, and that the volume of secondary waste is reduced by burning the used TANNIX. We have replaced its radioactive liquid waste treatment system from the conventional co-precipitation process to adsorption process by using TANNIX. TANNIX was founded to be more effective for the recovery of Pu, TRU, and hexavalent chromium Cr-(VI) as well as Uranium. (author)

PROBABILISTIC FINITE ELEMENT ANALYSIS OF A HEAVY DUTY RADIATOR UNDER INTERNAL PRESSURE LOADING

Directory of Open Access Journals (Sweden)

ROBIN ROY P.

2017-09-01

Full Text Available Engine cooling is vital in keeping the engine at most efficient temperature for the different vehicle speed and operating road conditions. Radiator is one of the key components in the heavy duty engine cooling system. Heavy duty radiator is subjected to various kinds of loading such as pressure, thermal, vibration, internal erosion, external corrosion, creep. Pressure cycle durability is one of the most important characteristic in the design of heavy duty radiator. Current design methodologies involve design of heavy duty radiator using the nominal finite element approach which does not take into account of the variations occurring in the geometry, material and boundary condition, leading to over conservative and uneconomical designs of radiator system. A new approach is presented in the paper to integrate traditional linear finite element method and probabilistic approach to design a heavy duty radiator by including the uncertainty in the computational model. As a first step, nominal run is performed with input design variables and desired responses are extracted. A probabilistic finite elementanalysis is performed to identify the robust designs and validated for reliability. Probabilistic finite element includes the uncertainty of the material thickness, dimensional and geometrical variation. Gaussian distribution is employed to define the random variation and uncertainty. Monte Carlo method is used to generate the random design points.Output response distributions of the random design points are post-processed using different statistical and probability technique to find the robust design. The above approach of systematic virtual modelling and analysis of the data helps to find efficient and reliable robust design.

Nuclear fuel element

International Nuclear Information System (INIS)

Iwano, Yoshihiko.

1993-01-01

Microfine cracks having a depth of less than 10% of a pipe thickness are disposed radially from a central axis each at an interval of less than 100 micron over the entire inner circumferential surface of a zirconium alloy fuel cladding tube. For manufacturing such a nuclear fuel element, the inside of the cladding tube is at first filled with an electrolyte solution of potassium chloride. Then, electrolysis is conducted using the cladding tube as an anode and the electrolyte solution as a cathode, and the inner surface of the cladding tube with a zirconium dioxide layer having a predetermined thickness. Subsequently, the cladding tube is laid on a smooth steel plate and lightly compressed by other smooth steel plate to form microfine cracks in the zirconium dioxide layer on the inner surface of the cladding tube. Such a compressing operation is continuously applied to the cladding tube while rotating the cladding tube. This can inhibit progress of cracks on the inner surface of the cladding tube, thereby enabling to prevent failure of the cladding tube even if a pellet/cladding tube mechanical interaction is applied. Accordingly, reliability of the nuclear fuel elements is improved. (I.N.)

LIBS detection of heavy metal elements in liquid solutions by using wood pellet as sample matrix

International Nuclear Information System (INIS)

Wen Guanhong; Sun Duixiong; Su Maogen; Dong Chenzhong

2013-01-01

Laser-induced breakdown spectroscopy (LIBS) has been applied to the analysis of heavy metals in liquid sample. A new approach was presented to improve the detection limit and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions, respectively. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to obtained LOD of 0.07 ppm for Cr element in solutions. (author)

LIBS Detection of Heavy Metal Elements in Liquid Solutions by Using Wood Pellet as Sample Matrix

International Nuclear Information System (INIS)

Wen Guanhong; Sun Duixiong; Su Maogen; Dong Chenzhong

2014-01-01

Laser-induced breakdown spectroscopy (LIBS) has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection (LOD) and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to the obtained LOD of 0.07 ppm for Cr element in solutions

Effect of heavy atoms on photochemically induced dynamic nuclear polarization in liquids

Science.gov (United States)

Okuno, Yusuke; Cavagnero, Silvia

2018-01-01

Given its short hyperpolarization time (∼10-6 s) and mostly non-perturbative nature, photo-chemically induced dynamic nuclear polarization (photo-CIDNP) is a powerful tool for sensitivity enhancement in nuclear magnetic resonance. In this study, we explore the extent of 1H-detected 13C nuclear hyperpolarization that can be gained via photo-CIDNP in the presence of small-molecule additives containing a heavy atom. The underlying rationale for this methodology is the well-known external-heavy-atom (EHA) effect, which leads to significant enhancements in the intersystem-crossing rate of selected photosensitizer dyes from photoexcited singlet to triplet. We exploited the EHA effect upon addition of moderate amounts of halogen-atom-containing cosolutes. The resulting increase in the transient triplet-state population of the photo-CIDNP sensitizer fluorescein resulted in a significant increase in the nuclear hyperpolarization achievable via photo-CIDNP in liquids. We also explored the internal-heavy-atom (IHA) effect, which is mediated by halogen atoms covalently incorporated into the photosensitizer dye. Widely different outcomes were achieved in the case of EHA and IHA, with EHA being largely preferable in terms of net hyperpolarization.

The importance of heavy water in nuclear technology

International Nuclear Information System (INIS)

Gharib, A.G.

2004-01-01

Due to similarities of chemical and almost physical properties in H 2 O and D 2 O but differences in nuclear and particle peculiarities provide valuable application for D 2 O. To sustain a controlled chain reaction, the energy of neutrons produced by fission must be reduced through collisions with other nuclei, a process called moderation. A good moderator has a mass close to that of the neutron to maximize energy loss per collision and a very small neutron capture cross section to minimize unwanted nuclear reactions. Deuterium is far the best moderator, more than 80 times better than hydrogen and 30 times better than 12 C ir 18 O. Heavy water is almost as good as deuterium and has the distinct advantage of being a nonflammable liquid. Heavy water is also an excellent neutron reflector, and thus decreases the number of neutrons that escape the reactor core without participating in fission reactions. For this reason a feasibility study and subsequently a technical survey was carried out on engineering of a pilot scale plant. As the result of this studies, the know-how of heavy water production on basis of selected method including dual temperature isotopic exchange and distillation techniques developed. Subsequently the primary and almost detail engineering documents prepared on best knowledge of our own engineers without external contribution

Spectroscopy of very heavy nuclei with a view to study super-heavy nuclei

International Nuclear Information System (INIS)

Khalfallah, F.

2007-08-01

Within the recent years, the spectroscopic study of single particle orbitals of very heavy elements (VHE) has become possible with the development of increasingly efficient experimental setups. This allows us, through nuclear deformation, to access with these deformed nuclei to orbitals situated around the Fermi level in the spherical superheavy elements (SHE) and learn more about the nuclear structure of these nuclei. The aim of this work is the spectroscopic studies of heavy and very heavy elements. Because of the experimental difficulties associated with the fusion reactions in the VHE region, a detailed optimization studies is essential. Simulation of energy loss and angular straggling of these nuclei due to the interaction in the target and to neutron's evaporation was carried out and allowed us to optimize the angular acceptance of the separators according to the target thickness. An extensive survey and exploration in the VHE region was also conducted on the basis of cross section's systematics in the literature and simulations carried out using the statistical code Hivap. In this framework, the possible extension of the range of validity of a set of Hivap parameters was investigated. This work has enabled us to prepare a list of experiments of interest for the production of very heavy nuclei. In this thesis, our work was concentrated on the spectroscopy of the nuclei No 256 et Rf 256 for which two experimental proposals were accepted. The octupole deformations predicted in the actinides region is studied in another part of this thesis, a part witch is dedicated to the gamma spectroscopy of Pa 223 . The data from a new experiment carried out using the Jurogam-Ritu-Great setup are analysed and compared to previous results. They confirm the octupole deformed shape in this nucleus. (author)

Mechanism of nuclear dissipation in fission and heavy-ion reactions

International Nuclear Information System (INIS)

Nix, J.R.; Sierk, A.J.

1986-01-01

Recent advances in the theoretical understanding of nuclear dissipation at intermediate excitation energies are reviewed, with particular emphasis on a new surface-plus-window mechanism that involves interactions of either one or two nucleons with the moving nuclear surface and also, for dumbbell-like shapes encountered in fission and heavy-ion reactions, the transfer of nucleons through the window separating the two portions of the system. This novel dissipation mechanism provides a unified macroscopic description of such diverse phenomena as widths of isoscalar giant quadrupole and giant octupole resonances, mean fission-fragment kinetic energies and excitation energies, dynamical thresholds for compound-nucleus formation, enhancement in neutron emission prior to fission, and widths of mass and charge distributions in deep-inelastic heavy-ion reactions. 41 refs., 8 figs

Nucleosynthesis of heavy elements by the photonuclear reaction

International Nuclear Information System (INIS)

Hayakawa, Takehito

2002-01-01

Nucleosynthesis of heavy elements is important for understanding of the site mechanism in the stellar and cosmochronology. The nuclei heavier than iron have been synthesized mainly by the s-process and the β-decay after the r-process. The light isotope p-nuclei produced by the photonuclear reaction in Type II supernovae explosions. In order to understand the role of each process, the ratios of the processes are calculated. I propose the experimental plan using the photon sources. (author)

Dynamics of light, intermediate, heavy and superheavy nuclear ...

Indian Academy of Sciences (India)

2014-05-01

May 1, 2014 ... Various features related to the dynamics of competing decay modes of nuclear systems are explored by addressing the experimental data of a number of reactions in light, intermediate, heavy and superheavy mass regions. The DCM, being a non-statistical description for the decay of a com- pound nucleus ...

System for assembling nuclear fuel elements

International Nuclear Information System (INIS)

1980-01-01

An automatic system is described for assembling nuclear fuel elements, in particular those employing mixed oxide fuels. The system includes a sealing mechanism which allows movement during the assembling of the fuel element along the assembly stations without excessive release of contaminants. (U.K.)

X-ray Ionization of Heavy Elements Applied to Protoplanetary Disks

NARCIS (Netherlands)

Ádámkovics, Máté; Glassgold, Alfred E.; Meijerink, Rowin

The consequences of the Auger effect on the population of heavy-element ions are analyzed for the case of relatively cool gas irradiated by keV X-rays with intended applications to the accretion disks of young stellar objects. Highly charged ions are rapidly reduced to the doubly charged state in

Trace elements and heavy metals in hair of stage III breast cancer patients.

Science.gov (United States)

Benderli Cihan, Yasemin; Sözen, Selim; Oztürk Yıldırım, Sema

2011-12-01

This prospective study was designed to compare the hair levels of 36 elements in 52 patients with stage III breast cancer to those of an equal number of healthy individuals. Principal component and cluster analysis were used for source of identification and apportionment of heavy metals and trace elements in these two groups. A higher average level of iron was found in samples from patients while controls had higher levels of calcium. Both patients and controls had elevated levels of tin, magnesium, zinc, and sodium. Almost all element values in cancer patients showed higher dispersion and asymmetry than in healthy controls. Between the two groups, there were statistically significant differences in the concentrations of silver, arsenic, gold, boron, barium, beryllium, calcium, cadmium, cerium, cobalt, cesium, gadolinium, manganese, nickel, lead, antimony, scandium, selenium, and zinc (p heavy metals and trace elements in the hair of breast cancer patients in comparison to healthy controls. These results could be of significance in the diagnosis of breast cancer.

Tests on the synthesis of superheavy elements

International Nuclear Information System (INIS)

Anon.

1981-01-01

The article briefly summarizes the study of superheavy elements, starting with speculations on the existence of relatively long-living nuclei via theoretical works to nuclear properties and chemical properties, search for the longest-living nuclei of the calculated stability island in nature, up to the attempts to produce such superheavy elements in large heavy ion accelerators (Berkely, Dubna, Darmstadt, Orsay). Principle and problems of the two methods to achieve a synthesis of such heavy nuclei, i. e. fusion reactions and transfer reactions, are briefly discussed. (RB) [de

Nuclear fuel element

International Nuclear Information System (INIS)

Hirama, H.

1978-01-01

A nuclear fuel element comprises an elongated tube having upper and lower end plugs fixed to both ends thereof and nuclear fuel pellets contained within the tube. The fuel pellets are held against the lower end plug by a spring which is supported by a setting structure. The setting structure is maintained at a proper position at the middle of the tube by a wedge effect caused by spring force exerted by the spring against a set of balls coacting with a tapered member of the setting structure thereby wedging the balls against the inner wall of the tube, and the setting structure is moved free by pushing with a push bar against the spring force so as to release the wedge effect

Nuclear fuel element

International Nuclear Information System (INIS)

Hirayama, Satoshi; Kawada, Toshiyuki; Matsuzaki, Masayoshi.

1980-01-01

Purpose: To provide a fuel element for reducing the mechanical interactions between a fuel-cladding tube and the fuel element and for alleviating the limits of the operating conditions of a reactor. Constitution: A fuel element having mainly uranium dioxide consists of a cylindrical outer pellet and cylindrical inner pellet inserted into the outer pellet. The outer pellet contains two or more additives selected from aluminium oxide, beryllium oxide, magnesium oxide, silicon oxide, sodium oxide, phosphorus oxide, calcium oxide and iron oxide, and the inner pellet contains nuclear fuel substance solely or one additive selected from calcium oxide, silicon oxide, aluminium oxide, magnesium oxide, zirconium oxide and iron oxide. The outer pellet of the fuel thus constituted is reduced in mechanical strength and also in the mechanical interactions with the cladding tube, and the plastic fluidity of the entire pellet is prevented by the inner pellet increased in the mechanical strength. (Kamimura, M.)

AMS advances in the geosciences and heavy-element analysis

International Nuclear Information System (INIS)

Rucklidge, J.C.; Wilson, G.C.; Kilius, L.R.

1990-01-01

Until recently small accelerators, such as the 2 MV Tandetron, have been used only for the lighter elements such as 10 Be, 14 C and 26 Al, while the heavier isotopes such as 36 Cl, 41 Ca and 129 I have been perceived to need the higher energies only available on large machines. We describe the use of a Tandetron for measurement of 129 I/ 127 I at natural levels, and the in situ assay of some heavy elements of interest in economic geology at detection levels superior to those of more widely used techniques. A few recently described novel applications of AMS are also given. (orig.)

K-edge x-ray fluorescence analysis for actinide and heavy elements solution concentration measurements

International Nuclear Information System (INIS)

Camp, D.C.

1984-07-01

Advantages of using Co-57 as an exciter for K XRFA include: a compact design that requires no x-ray tubes; the exciter-detector assembly locates remote from support electronics; on-line, at-line, or off-line configurations for monitor/measurements; systems that can be run by semi-skilled technicians, once programmed; and operated via remote terminals with results sent to control rooms; heavy element concentrations that are measurable thru industrial pipes; independent of minor changes in solution matrix or source half life with concentration results reported in near-real-time; a dynamic range of measurable concentrations that is greater than 10 4 ; measurement times that are reasonable even at 1 gram/liter; and for nuclear safeguards, it provides the <0.5% accuracy required by DOE for the accountability of U, Pu, or both, once the system is calibrated

The influence of nuclear structure on the Lamb shift in hydrogenlike heavy atoms

International Nuclear Information System (INIS)

Beier, T.; Plunien, G.; Soff, G.

1997-01-01

We evaluate and list the various contributions to the Lamb shift in hydrogenlike heavy atoms which arise from parameters describing shape, size and structure of the nucleus. We compare these contributions with those obtained from quantum electrodynamics. It is found that in heavy nuclei, nuclear contributions depending on experimental parameters and nuclear models are of the same size as QED contributions of order a 2 . Therefore, in these systems the theoretical predictions for binding energies are limited by the exact knowledge of the nuclear parameters. In addition, we tabulate all corrections contributing to the 1s 1/2 Lamb shift in hydrogenlike Pb and U. (orig.)

The quality control for biological-shield heavy concrete construction of nuclear power project

International Nuclear Information System (INIS)

Sun Hongjun; Ma Xinchao

2012-01-01

The paper introduces the function and characteristics of biological protective heavy-concrete, and its main application scope and role in Fangjiashan nuclear power project. From the aspects of raw material selection, mixing ratio test, heavy concrete production, the paper discusses the main control points of heavy concrete construction process, points out the basic characteristics of heavy concrete construction, and put forward measures to prevent density non-uniformity during heavy concrete construction and to control slump during transportation. Results prove that reasonable construction process control can assure the engineering quality. (authors)

Plant Design Nuclear Fuel Element Production Capacity Optimization to Support Nuclear Power Plant in Indonesia

International Nuclear Information System (INIS)

Bambang Galung Susanto

2007-01-01

The optimization production capacity for designing nuclear fuel element fabrication plant in Indonesia to support the nuclear power plant has been done. From calculation and by assuming that nuclear power plant to be built in Indonesia as much as 12 NPP and having capacity each 1000 MW, the optimum capacity for nuclear fuel element fabrication plant is 710 ton UO 2 /year. The optimum capacity production selected, has considered some aspects such as fraction batch (cycle, n = 3), length of cycle (18 months), discharge burn-up value (Bd) 35,000 up 50,000 MWD/ton U, enriched uranium to be used in the NPP (3.22 % to 4.51 %), future market development for fuel element, and the trend of capacity production selected by advances country to built nuclear fuel element fabrication plant type of PWR. (author)

Chemical and nuclear properties of lawrencium (element 103) and hahnium (element 105)

International Nuclear Information System (INIS)

Henderson, R.A.

1990-01-01

The chemical and nuclear properties of Lr and Ha have been studied, using 3-minute 260 Lr and 35-second 262 Ha. The crystal ionic radius of Lr 3+ was determined by comparing its elution position from a cation-exchange resin column with those of lanthanide elements having known ionic radii. Comparisons are made to the ionic radii of the heavy actinides, Am 3+ through Es 3+ , obtained by x-ray diffraction methods, and to Md 3+ and Fm 3+ which were determined in the same manner as Lr 3+ . The hydration enthalpy of -3622 kJ/mol was calculated from the crystal ionic radius using an empirical form of the Born equation. Comparisons to the spacings between the ionic radii of the heaviest members of the lanthanide series show that the 2Z spacing between Lr 3+ and Md 3+ is anomalously small, as the ionic radius of Lr 3+ of 0.0886 nm is significantly smaller than had been expected. The chemical properties of Ha were determined relative to the lighter homologs in group 5, Nb and Ta. Group 4 and group 5 tracer activities, as well as Ha, were absorbed onto glass surfaces as a first step toward the determination of the chemical properties of Ha. Ha was found to adsorb on surfaces, a chemical property unique to the group 5 elements, and as such demonstrates that Ha has the chemical properties of a group 5 element. A solvent extraction procedure was adapted for use as a micro-scale chemical procedure to examine whether or not Ha displays eka-Ta-like chemical under conditions where Ta will be extracted into the organic phase and Nb will not. Under the conditions of this experiment Ha did not extract, and does not show eka-Ta-like chemical properties

Study on the prediction of soil heavy metal elements content based on visible near-infrared spectroscopy

Science.gov (United States)

Liu, Jinbao; Zhang, Yang; Wang, Huanyuan; Du, Yichun

2018-06-01

The estimation of soils heavy metal content can reflect the impending surroundings of surface, which lays theoretical foundation for using covered vegetation to monitor environment and investigate resource. In this study, the contents of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb in 44 soil samples were collected from Fufeng County, Yangling County and Wugong County, Shaanxi Province and were used as data sources. ASD FieldSpec HR (350-2500 nm), and then the NOR, MSC and SNV of the reflectance were pretreated, the first deviation, second deviation and reflectance reciprocal logarithmic transformation were carried out. The optimal spectroscopy estimation model of nine heavy metal elements of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb was established by regression method. Comparing the diffuse reflectance characteristics of different heavy metal contents and the effect of different pretreatment methods on the establishment of soil heavy metal spectral inversion model. The results of chemical analysis show that there was a serious Hg pollution in the study area, and the Cd content was close to the critical value. The results show that: (1) NOR, MSC and SNV were adopted for the acquisition of visible near-infrared. Combining differential transformation can improve the information of heavy metal elements in the soil, and use the correlation band energy Significantly improve the stability and predictability of the model. (2) The modeling accuracy of the optimal model of nine heavy metal spectra of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb by PLSR method were 0.70, 0.79, 0.69, 0.81, 0.86, 0.58, 0.55, 0.99, 0.62. (3) The optimal estimation model of different elements using different treatment methods has better stability and higher precision, and can realize the rapid prediction of nine kinds of heavy metal elements in this region.

Application of radioanalytical techniques in the study of the products of heavy-ion reactions

International Nuclear Information System (INIS)

Hoffman, D.C.

1989-01-01

The use of heavy ions to induce nuclear reactions was reported as early as 1950. Since then it has been one of the most active areas of nuclear research. Intense beams of ions as heavy as uranium with energies high enough to overcome the Coulomb barriers of even the heaviest elements are available. The large variety of possible reactions gives rise to a multitude of products, which have been studied by many chemical and physical techniques. Chemical techniques have been of special value for the separation and unequivocal identification of low-yield species from the plethora of other nuclides present. Heavy-ion reactions have been essential for the production of the transmendelevium elements and a host of new isotopes. The systematics of compound nucleus reactions, transfer reactions and deeply inelastic reactions have been elucidated using chemical techniques. The variety of chemical procedures and techniques which have been developed for the study of heavy-ion reactions and their products has been examined. The determination of the chemical properties of the transmendelevium elements, which are very short-lived and can only be produced an ''atom at a time'' via heavy-ion reactions, is discussed. (author)

Frontiers of heavy-ion physics and superheavy elements

International Nuclear Information System (INIS)

Muenzenberg, G.

2003-01-01

This contribution will focus on three topics of GSI nuclear structure research: superheavy elements, direct mass measurements in the storage ring, and studies of fission in reversed kinematics. The GSI project for a new synchrotron facility will be outlined

Placental transfer of the actinides and related heavy elements

International Nuclear Information System (INIS)

Sikov, M.R.

1987-01-01

This manuscript presents a selective review of the literature dealing with prenatal exposure of experimental animals and humans to actinides and related heavy elements, and uses this information to consider comparative aspects of placental transfer and fetoplacental distribution. General patterns have been derived from typical quantitative values, and used to compare similarities and dissimilarities, and to examine factors responsible for observed differences. 37 refs.; 1 figure; 2 tabs

Origin of the heavy elements in binary neutron-star mergers from a gravitational-wave event.

Science.gov (United States)

Kasen, Daniel; Metzger, Brian; Barnes, Jennifer; Quataert, Eliot; Ramirez-Ruiz, Enrico

2017-11-02

The cosmic origin of elements heavier than iron has long been uncertain. Theoretical modelling shows that the matter that is expelled in the violent merger of two neutron stars can assemble into heavy elements such as gold and platinum in a process known as rapid neutron capture (r-process) nucleosynthesis. The radioactive decay of isotopes of the heavy elements is predicted to power a distinctive thermal glow (a 'kilonova'). The discovery of an electromagnetic counterpart to the gravitational-wave source GW170817 represents the first opportunity to detect and scrutinize a sample of freshly synthesized r-process elements. Here we report models that predict the electromagnetic emission of kilonovae in detail and enable the mass, velocity and composition of ejecta to be derived from observations. We compare the models to the optical and infrared radiation associated with the GW170817 event to argue that the observed source is a kilonova. We infer the presence of two distinct components of ejecta, one composed primarily of light (atomic mass number less than 140) and one of heavy (atomic mass number greater than 140) r-process elements. The ejected mass and a merger rate inferred from GW170817 imply that such mergers are a dominant mode of r-process production in the Universe.

Apparatus for locating defective nuclear fuel elements

International Nuclear Information System (INIS)

Lawrie, W.E.

1979-01-01

An ultrasonic search unit for locating defective fuel elements within a fuel assembly used in a water cooled nuclear reactor is presented. The unit is capable of freely traversing the restricted spaces between the fuel elements

Theory of nuclear excitation by electron capture for heavy ions

International Nuclear Information System (INIS)

Palffy, Adriana; Scheid, Werner; Harman, Zoltan

2006-01-01

We investigate the resonant process of nuclear excitation by electron capture (NEEC), in which a continuum electron is captured into a bound state of an ion with the simultaneous excitation of the nucleus. In order to derive the cross section a Feshbach projection operator formalism is introduced. Nuclear states and transitions are described by a nuclear collective model and making use of experimental data. Transition rates and total cross sections for NEEC followed by the radiative decay of the excited nucleus are calculated for various heavy-ion collision systems

Heavy-Ion Reactions: a current awareness bulletin

International Nuclear Information System (INIS)

Kinser, W.H.

1985-01-01

This current awareness bulletin announces on a semimonthly basis the current worldwide information entered into the Energy Data Base on theoretical and experimental studies (including instrumentation) of heavy-ion (A > 4) nuclear reactions for nuclear structure studies; for producing new isotopes and superheavy elements for nuclear, atomic, and chemical properties studies; for understanding quantum chromodynamics as an exact theory of the strong nuclear force; and for studying the equations of state and phases of nuclear matter (pion condensate and quark matter) of special interest in astrophysics, and cosmology. An abstract is included with each citation. Regular publication began in January 1985

HAIR HEAVY METAL AND ESSENTIAL TRACE ELEMENT CONCENTRATION IN CHILDREN WITH AUTISM SPECTRUM DISORDER.

Science.gov (United States)

Tabatadze, T; Zhorzholiani, L; Kherkheulidze, M; Kandelaki, E; Ivanashvili, T

2015-11-01

Our study aims evaluation of level of essential trace elements and heavy metals in the hair samples of children with autistic spectrum disorder (ASD) and identification of changes that are associated with autistic spectrum disorders. Case-control study was conducted at Child Development Center of Iashvili Children's Central Hospital (LD).We studied 60 children aged from 4 to 5 years old. The concentrations of 28 elements among (Ca,Zn, K, Fe, Cu, Se, Mn, Cr, S, Br, Cl, Co, Ag, V, Ni, Rb, Mo, Sr, Ti, Ba, Pb, As, Hg, Cd, Sb, Zr, Sn, Bi) them trace elements and toxic metals) were determined in scalp hair samples of children (n=30) with autistic spectrum disorder (ASD) and from control group of healthy children (n=30) with matched sex and age. Micro-elemental status was detected in the hair, with roentgen-fluorescence spectrometer method (Method MBИ 081/12-4502-000, Apparatus ALVAX- CIP, USA - UKRAIN) .To achieve the similarity of study and control groups, pre and postnatal as well as family and social history were assessed and similar groups were selected. Children with genetic problems, malnourished children, children from families with social problems were excluded from the study. The diagnosis of ASD were performed by pediatrician and psychologist (using M-CHAT and ADOS) according to DSM IV (Diagnostic and Statistical Manual of Mental Disorders from the American Psychiatric association) criteria. The study was statistically analyzed using computer program SPSS 19. Deficiencies of essential trace microelements revealed in both group, but there was significant difference between control and studied groups. The most deficient element was zinc (92% in target and 20% in control), then - manganese (55% and 8%) and selenium (38% and 4%). In case of cooper study revealed excess concentration of this element only in target group in 50% of cases. The contaminations to heavy metals were detected in case of lead (78% and 16), mercury (43% and 10%) and cadmium (38% and 8%). The

Fuel element concept for long life high power nuclear reactors

Science.gov (United States)

Mcdonald, G. E.; Rom, F. E.

1969-01-01

Nuclear reactor fuel elements have burnups that are an order of magnitude higher than can currently be achieved by conventional design practice. Elements have greater time integrated power producing capacity per unit volume. Element design concept capitalizes on known design principles and observed behavior of nuclear fuel.

Maria Goeppert Mayer's Theoretical Work on Rare-Earth and Transuranic Elements

OpenAIRE

Wang, Frank Y.

2008-01-01

After the discovery of element 93 neptunium by Edwin McMillan and Philip H. Abelson in 1941, Maria Goeppert Mayer applied the Thomas-Fermi model to calculate the electronic configuration of heavy elements and predicted the occurrence of a second rare-earth series in the vicinity of elements 91 or 92 extending to the transuranic elements. Mayer was motivated by Enrico Fermi, who was at the time contemplating military uses of nuclear energy. Historical development of nuclear science research le...

Nuclear data newsletter. No. 7

Energy Technology Data Exchange (ETDEWEB)

NONE

1984-12-01

This issue lists new nuclear data libraries received by the IAEA Nuclear Data Section: JENDL-2; EXFOR-V; Atomic mass tables; ENDF/B-5; the ENDF/B processing codes; and nuclear data handbooks. The libraries are concerned with recommended heavy element radionuclide decay data; nuclear theory for applications; and charts of nuclides. A selection of new relevant documents is also listed.

Monitoring arrangement for vented nuclear fuel elements

International Nuclear Information System (INIS)

Campana, R.J.

1981-01-01

In a nuclear fuel reactor core, fuel elements are arranged in a closely packed hexagonal configuration, each fuel element having diametrically opposed vents permitting 180 0 rotation of the fuel elements to counteract bowing. A grid plate engages the fuel elements and forms passages for communicating sets of three, four or six individual vents with respective monitor lines in order to communicate vented radioactive gases from the fuel elements to suitable monitor means in a manner readily permitting detection of leakage in individual fuel elements

Dynamical calculations of nuclear fission and heavy-ion reactions

International Nuclear Information System (INIS)

Nix, J.R.; Sierk, A.J.

1984-01-01

With the goal of determining the magnitude and mechanism of nuclear dissipation from comparisons of predictions with experimental data, we describe recent calculations in a unified macroscopic-microscopic approach to large-amplitude collective nuclear motion such as occurs in fission and heavy-ion reactions. We describe the time dependence of the distribution function in phase space of collective coordinates and momenta by a generalized Fokker-Planck equation. The nuclear potential energy of deformation is calculated as the sum of repulsive Coulomb and centrifugal energies and an attractive Yukawa-plus-exponential potential, the inertia tensor is calculated for a superposition of rigid-body rotation and incompressible, nearly irrotational flow by use of the Werner-Wheeler method, and the dissipation ensor that describes the conversion of collective energy into single-particle excitation energy is calculated for two prototype mechanisms that represent opposite extremes of large and small dissipation. We solve the generalized Hamilton equations of motion for the first moments of the distribution function to obtain the mean translational fission-fragment kinetic energy and mass of a third fragment that sometimes forms between the two end fragments, as well as dynamical thresholds, capture cross sections, and ternary events in heavy-ion reactions. 33 references

Nuclear microprobe study of heavy metal uptake and transport in aquatic plant species

International Nuclear Information System (INIS)

Kertesz, Zs.; Kocsar, I.; Szikszai, Z.; Lakatos, Gy.

2005-01-01

Complete text of publication follows. In aquatic ecosystems water contamination by trace metals is one of the main types of pollution that may stress the biotic community. Although some metals are needed as micronutrients for autotrophic organisms, they can have toxic effects at higher concentration. Aquatic plants can take up large quantities of nutrients and metals from the environment, they can live under extreme environmental conditions therefore they are being increasingly used in remediation processes to reduce contamination. Besides the usually applied bulk analytical techniques quantitative micro-PIXE investigation of the macro, micro and trace element distribution within the root can lead to a better understanding of the heavy metal up-take, transport and detoxification mechanisms of the plants and thus helps to select the proper species for the remedial activity, or possibly to increase the efficiency of the remediation. In this work we determined the elemental distributions in root cross sections and along the roots of reed (Phragmaties australis), bulrush (Typha angustifolia) and sea club-rush (Bolboschoemus maritimus) using the Debrecen nuclear microprobe. The plants originate from the dried units of the wastewater sedimentation pond system of the tannery of Kunszentmarton. 1500 m 3 waste water containing lime, sodium-salts, ammonium-salts, chromium-salts, sodium, chlorine and magnesium ions, sulphur and organic material was released to the pond system every day till 1988. The chosen species are the dominant species of the area, composing 85-90% of the green plant covering. This heavily contaminated area has been regularly monitored by the colleagues of the Dept. of Applied Ecology of the Univ. of Debrecen since 1998. They focused their work the potentially toxic heavy metal chromium. In order to conserve the samples in the living state, the roots were frozen in liquid nitrogen. 16-20 μm thick cross sections were made with cryo-microtome, and all the

Nuclear fuel elements

International Nuclear Information System (INIS)

Kawada, Toshiyuki; Hirayama, Satoshi; Yoneya, Katsutoshi.

1980-01-01

Purpose: To enable load-depending operation as well as moderation for the restriction of operation conditions in the present nuclear reactors, by specifying the essential ingredients and the total weight of the additives to UO 2 fuel substances. Constitution: Two or more additives selected from Al 2 O 3 , B 2 O, CaO, MgO, SiO 2 , Na 2 O and P 2 O 5 are added by the total weight of 2 - 5% to fuel substances consisting of UO 2 or a mixture of UO 2 and PuO 2 . When the mixture is sintered, the strength of the fuel elements is decreased and the fuel-cladding interactions due to the difference in the heat expansion coefficients between the ceramic fuel elements and the metal claddings are decreased to a substantially harmless degree. (Horiuchi, T.)

Study on the prediction of soil heavy metal elements content based on visible near-infrared spectroscopy.

Science.gov (United States)

Liu, Jinbao; Zhang, Yang; Wang, Huanyuan; Du, Yichun

2018-06-15

The estimation of soils heavy metal content can reflect the impending surroundings of surface, which lays theoretical foundation for using covered vegetation to monitor environment and investigate resource. In this study, the contents of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb in 44 soil samples were collected from Fufeng County, Yangling County and Wugong County, Shaanxi Province and were used as data sources. ASD FieldSpec HR (350-2500nm), and then the NOR, MSC and SNV of the reflectance were pretreated, the first deviation, second deviation and reflectance reciprocal logarithmic transformation were carried out. The optimal spectroscopy estimation model of nine heavy metal elements of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb was established by regression method. Comparing the diffuse reflectance characteristics of different heavy metal contents and the effect of different pretreatment methods on the establishment of soil heavy metal spectral inversion model. The results of chemical analysis show that there was a serious Hg pollution in the study area, and the Cd content was close to the critical value. The results show that: (1) NOR, MSC and SNV were adopted for the acquisition of visible near-infrared. Combining differential transformation can improve the information of heavy metal elements in the soil, and use the correlation band energy Significantly improve the stability and predictability of the model. (2) The modeling accuracy of the optimal model of nine heavy metal spectra of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb by PLSR method were 0.70, 0.79, 0.69, 0.81, 0.86, 0.58, 0.55, 0.99, 0.62. (3) The optimal estimation model of different elements using different treatment methods has better stability and higher precision, and can realize the rapid prediction of nine kinds of heavy metal elements in this region. Copyright © 2018 Elsevier B.V. All rights reserved.

Coefficients of viscosity for heavy impurity element in tokamak

Energy Technology Data Exchange (ETDEWEB)

El-Sharif, R N; Bekhit, A M [Plasma Physics dept., NRC, Atomic energy Authority, Cairo, (Egypt)

1997-12-31

The transport of heavy impurity element in to tokamak was studied theoretically. The viscosity coefficients of chromium impurities has been calculated in 13 and 21 moment approximation, in the limit of strong fields where is the gyrofrequency of species it was found that the off diagonal coefficient approximately tends to zero. This means that the friction force in the off-diagonal direction is very small, for the perpendicular viscosity coefficient the two approximation coincide to each other. 3 figs.

Long-lived heavy mass elements half-lives (A > 125)

International Nuclear Information System (INIS)

Holden, N.E.

1985-01-01

Reported values of half-lives of intermediate mass and heavy elements are evaluated. The evaluation analysis estimates the systematic error the resulting standard deviation. Recommended values are then presented for 128 Te, 130 Te, 129 I, 138 La, 144 Nd, 145 Nd, /sup 146,147,148/Sm, 152 Gd, 154 Dy, 176 Lu, 174 Hf, 180 Ta, 187 Re, 186 Os, 190 Pt, /sup 204,205/Pb, and /sup 230,232/Th. 103 refs., 21 tabs

Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Upgrade Activities

Science.gov (United States)

Emrich, William J. Jr.; Moran, Robert P.; Pearson, J. Boise

2012-01-01

To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). This device can simulate the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner so as to accurately reproduce the temperatures and heat fluxes which would normally occur as a result of nuclear fission and would be exposed to flowing hydrogen. Initial testing of a somewhat prototypical fuel element has been successfully performed in NTREES and the facility has now been shutdown to allow for an extensive reconfiguration of the facility which will result in a significant upgrade in its capabilities

Improved nuclear fuel element

International Nuclear Information System (INIS)

1974-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has a metal liner disposed between the cladding and the nuclear fuel material and a high lubricity material in the form of a coating disposed between the liner and the cladding. The liner preferably has a thickness greater than the longest fission product recoil distance and is composed of a low neutron capture cross-section material. The liner is preferably composed of zirconium, an alloy of zirconium, niobium or an alloy of niobium. The liner serves as a preferential reaction site for volatile impurities and fission products and protects the cladding from contact and reaction with such impurities and fission products. The high lubricity material acts as an interface between the liner and the cladding and reduces localized stresses on the cladding due to fuel expansion and cracking of the fuel

Nuclear fuel element

International Nuclear Information System (INIS)

Armijo, J.S.

1977-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed which has a composite cladding having a substrate, a metal barrier metallurgically bonded to the inside surface of the substrate and an inner layer metallurgically bonded to the inside surface of the metal barrier. In this composite cladding, the inner layer and the metal barrier shield the substrate from any impurities or fission products from the nuclear fuel material held within the composite cladding. The metal barrier forms about 1 to about 4 percent of the thickness of the cladding and is comprised of a metal selected from the group consisting of niobium, aluminum, copper, nickel, stainless steel, and iron. The inner layer and then the metal barrier serve as reaction sites for volatile impurities and fission products and protect the substrate from contact and reaction with such impurities and fission products. The substrate and the inner layer of the composite cladding are selected from conventional cladding materials and preferably are a zirconium alloy. Also in a preferred embodiment the substrate and the inner layer are comprised of the same material, preferably a zirconium alloy. 19 claims, 2 figures

HISTORY OF THE ORIGIN OF THE CHEMICAL ELEMENTS AND THEIR DISCOVERERS

International Nuclear Information System (INIS)

Holden, N.E.

2001-01-01

What do we mean by a chemical element? A chemical element is matter, all of whose atoms are alike in having the same positive charge on the nucleus and the same number of extra-nuclear electrons. As we shall see in the following elemental review, the origin of the chemical elements show a wide diversity with some of these elements having an origin in antiquity, other elements having been discovered within the past few hundred years and still others have been synthesized within the past fifty years via nuclear reactions on heavy elements since these other elements are unstable and radioactive and do not exist in nature

HISTORY OF THE ORIGIN OF THE CHEMICAL ELEMENTS AND THEIR DISCOVERIES.

Energy Technology Data Exchange (ETDEWEB)

HOLDEN,N.E.

2001-06-29

What do we mean by a chemical element? A chemical element is matter, all of whose atoms are alike in having the same positive charge on the nucleus and the same number of extra-nuclear electrons. As we shall see in the following elemental review, the origin of the chemical elements show a wide diversity with some of these elements having an origin in antiquity, other elements having been discovered within the past few hundred years and still others have been synthesized within the past fifty years via nuclear reactions on heavy elements since these other elements are unstable and radioactive and do not exist in nature.

Nuclear synergism of the light elements

International Nuclear Information System (INIS)

Harms, A.A.

1983-05-01

Some basic issues concerning accelerator initiated and fusion sustained nuclear energy systems are examined. For this purpose we identify selected nuclear fusion reactions characterized by a variable ion-to-neutron content and explore their intrinsic couplings and regenerative features. These are then related to particular systems concepts which emphasize fusion physics and accelerator technology. It is concluded that several light-element reaction systems possess appealing and interesting properties and can further be associated with selected advanced nuclear technologies. Their eventual implementation as nuclear energy systems requires further research in fusion physics, accelerator technology and mathematical physics. Because of the substantial potential benefits of such nuclear energy systems, it is concluded that research in this area should be pursued with much vigour. (orig.)

Simulation studies of acceleration of heavy ions and their elemental compositions

International Nuclear Information System (INIS)

Toida, Mieko; Ohsawa, Yukiharu

1996-07-01

By using a one-dimensional, electromagnetic particle simulation code with full ion and electron dynamics, we have studied the acceleration of heavy ions by a nonlinear magnetosonic wave in a multi-ion-species plasma. First, we describe the mechanism of heavy ion acceleration by magnetosonic waves. We then investigate this by particle simulations. The simulation plasma contains four ion species: H, He, O, and Fe. The number density of He is taken to be 10% of that of H, and those of O and Fe are much lower. Simulations confirm that, as in a single-ion-species plasma, some of the hydrogens can be accelerated by the longitudinal electric field formed in the wave. Furthermore, they show that magnetosonic waves can accelerate all the particles of all the heavy species (He, O, and Fe) by a different mechanism, i.e., by the transverse electric field. The maximum speeds of the heavy species are about the same, of the order of the wave propagation speed. These are in good agreement with theoretical prediction. These results indicate that, if high-energy ions are produced in the solar corona through these mechanisms, the elemental compositions of these heavy ions can be similar to that of the background plasma, i.e., the corona

In vivo detection of the toxic heavy elements, lead and cadmium

International Nuclear Information System (INIS)

Thomas, B.J.; Thomas, B.W.; Davey, J.F.; Baddeley, H.; Summers, V.; Craswell, P.

1986-01-01

Portable systems for the in vivo measurement of the toxic heavy elements, cadmium and lead are described. The cadmium concentration in either the liver or left kidney is determined using a technique of thermal neutron capture gamma-ray analysis. X-ray fluorescence analysis is used to measure lead within the bone of the second phalanx of the index finger. Each of the measurements is used as an index of long term exposure to the element and applied to screening of exposed industrial workers. The results of these industrial health applications are presented. Clinical application of the measurements to the study of the involvement of these elements in renal disease is described in brief. (author)

Application of the UKP-2-1 accelerator of heavy ions in the field of nuclear and radiation physics. Chapter 2

International Nuclear Information System (INIS)

2003-01-01

The UKP-2-1 accelerator is intended for research works conducting in the field of solid state physics, low energy nuclear physics, nuclear microanalysis, materials modification and others. The accelerator includes two autonomous beam transporting channels jointed by one accelerating potential. One of the channel is intended for hydrogen and inert gases' ions acceleration, obtained from duoplasmatron. The second one includes the source with cesium dispersion and it is intended for heavy ions acceleration. On the base of the accelerator the set of the analytical methods such as PIXE, RBS, NRA were developed allowing to study of samples element content, distribution of elements by depth, analysis of thin films thickness. The accelerator intensively using in the filed of inertial nuclear fusion and studies on Coulomb energy losses of plasma target fast protons. The experience of the accelerator in different environmental researches is gained as well. In particular of deuterium determination in the water samples by the nuclear reaction method and study of plutonium and uranium distribution in 'hot' particles by the proton-induced X-ray method are developed. Beginning of 1999 on the accelerator a new research activity trend related with nuclear physical analysis methods adaptation on charged particles beams for study of a biological objects has been developed. At present the accelerator hardware does not concedes to hardware of the best world laboratories

Fuel element for a nuclear reactor

International Nuclear Information System (INIS)

Linning, D.L.

1977-01-01

An improvement of the fuel element for a fast nuclear reactor described in patent 15 89 010 is proposed which should avoid possible damage due to swelling of the fuel. While the fuel element according to patent 15 89 010 is made in the form of a tube, here a further metal jacket is inserted in the centre of the fuel rod and the intermediate layer (ceramic uranium compound) is provided on both sides, so that the nuclear fuel is situated in the centre of the annular construction. Ceramic uranium or plutonium compounds (preferably carbide) form the fuel zone in the form of circular pellets, which are surrounded by annular gaps, so that gaseous fission products can escape. (UWI) [de

Empirical description of the element production cross sections in dissipative heavy-ion collisions

International Nuclear Information System (INIS)

Wollersheim, H.J.

1984-06-01

Correlations between experimental observables yield analytical expressions for the energy dsigma/dE and element distributions dsigma/dZ, d 2 sigma/dZdE in dissipative collisions. These empirical formulas are applied to twelve heavy ion systems at bombarding energies well above the Coulomb barrier. The element production can be calculated for all kinetic energies of the reaction fragments from the quasi-elastic region down to a minimum total kinetic energy Vsub(c)sup(def) which is the result of the Coulomb repulsion of two deformed nuclei prior to scission. In cases where the dissipative collisions are the dominant part of the reaction process, the deformed Coulomb energy can also be deduced from the total reaction cross section. For these heavy ion systems the empirical formulas depend only on quantities of the ingoing channels. Especially, the normalization of the Gaussian shaped element distributions indicates that the reminiscence on the entrance channel is not completely lost in dissipative collisions. For the 209 Bi + 136 Xe reaction at a laboratory bombarding energy of 1130 MeV the energy and element distributions are calculated which show an excellent agreement with the experimental data. (orig.)

Heavy density concrete for nuclear radiation shielding and power stations: [Part]2

International Nuclear Information System (INIS)

Singha Roy, P.K.

1987-01-01

This article is the second part of the paper entitled 'Heavy density concrete for nuclear radiation shielding and power stations'. In this part, some of the important properties of heavy density concrete are discussed. They include density, water retentivity, air content, permeability with special reference to concrete mixes used in India's nuclear power reactors. All these properties are affected to various extents by heating. Indian shield concrete is rarely subjected to temperatures above 60degC during its life, because of thermal shield protection. During placement, the maximum anticipated rise in temperature due to heat of hydration is restricted to around 45degC by chilling, if necessary to reduce shrinkage stresses and cracks. (M.G.B.)

Application of alpha spectrometry to the discovery of new elements by heavy-ion-beam bombardment

International Nuclear Information System (INIS)

Nitschke, J.M.

1983-05-01

Starting with polonium in 1898, α-spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, α-spectra have proved simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the natural α-decay series led to the very powerful method of genetically linking the decay of new elements to the well-established α-emission of daughter and granddaughter nuclei. This technique has been used for all recent discoveries of new elements including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for α-spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in He gas. Subsequent electrical deposition or a He-jet technique yielded samples that were not only thin enough for α-spectroscopy, but also for α- and #betta#-recoil experiments. Many variations of these methods have been developed and are discussed. For the synthesis of element 106 an aerosol-based recoil transport technique was devised. In the most recent experiments, α-spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10 - 6 s; while it was 10 - 1 to 10 0 s for He-jets and 10 1 to 10 3 s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyze them with these latest techniques. Again, α-spectrometry will play a major role since the expected signature for the decay of a SHE is a sequence of α-decays followed by spontaneous fission

Fundamental aspects of nuclear reactor fuel elements

International Nuclear Information System (INIS)

Olander, D.R.

1976-01-01

The book presented is designed to function both as a text for first-year graduate courses in nuclear materials and as a reference for workers involved in the materials design and performance aspects of nuclear power plants. The contents are arranged under the following chapter headings: statistical thermodynamics, thermal properties of solids, crystal structures, cohesive energy of solids, chemical equilibrium, point defects in solids, diffusion in solids, dislocations and grain boundaries, equation of state of UO 2 , fuel element thermal performance, fuel chemistry, behavior of solid fission products in oxide fuel elements, swelling due to fission gases, pore migration and fuel restructuring kinetics, fission gas release, mechanical properties of UO 2 , radiation damage, radiation effects in metals, interaction of sodium and stainless steel, modeling of the structural behavior of fuel elements and assemblies

Quark-level analogue of nuclear fusion with doubly heavy baryons.

Science.gov (United States)

Karliner, Marek; Rosner, Jonathan L

2017-11-01

The essence of nuclear fusion is that energy can be released by the rearrangement of nucleons between the initial- and final-state nuclei. The recent discovery of the first doubly charmed baryon , which contains two charm quarks (c) and one up quark (u) and has a mass of about 3,621 megaelectronvolts (MeV) (the mass of the proton is 938 MeV) also revealed a large binding energy of about 130 MeV between the two charm quarks. Here we report that this strong binding enables a quark-rearrangement, exothermic reaction in which two heavy baryons (Λ c ) undergo fusion to produce the doubly charmed baryon and a neutron n (), resulting in an energy release of 12 MeV. This reaction is a quark-level analogue of the deuterium-tritium nuclear fusion reaction (DT → 4 He n). The much larger binding energy (approximately 280 MeV) between two bottom quarks (b) causes the analogous reaction with bottom quarks () to have a much larger energy release of about 138 MeV. We suggest some experimental setups in which the highly exothermic nature of the fusion of two heavy-quark baryons might manifest itself. At present, however, the very short lifetimes of the heavy bottom and charm quarks preclude any practical applications of such reactions.

b-jet tagged nuclear modification factors in heavy ion collisions with CMS

CERN Document Server

Jung, Kurt

2014-01-01

The energy loss of jets in heavy-ion collisions is expected to depend on the flavor of the fragmenting parton. Thus, measurements of jet quenching as a function of flavor place powerful constraints on the thermodynamical and transport properties of the hot and dense medium. Measurements of the nuclear modification factors of the heavy-flavor-tagged jets in both PbPb and pPb collisions can quantify such energy loss effects. Specifically, pPb measurements provide crucial insights into the behavior of the cold nuclear matter effect, which is required to fully understand the hot and dense medium effects on jets in PbPb collisions. In this talk, we present the b-jet spectra and the first measurement of the nuclear modification factors as a function of transverse momentum and pseudorapidity, using the high statistics pp, pPb and PbPb data taken in 2011 and 2013.

Ageing evaluation model of nuclear reactors structural elements

International Nuclear Information System (INIS)

Ziliukas, A.; Jutas, A.; Leisis, V.

2002-01-01

In this article the estimation of non-failure probability by random faults on the structural elements of nuclear reactors is presented. Ageing is certainly a significant factor in determining the limits of nuclear plant lifetime or life extensions. Usually the non failure probability rates failure intensity, which is characteristic for structural elements ageing in nuclear reactors. In practice the reliability is increased incorrectly because not all failures are fixed and cumulated. Therefore, the methodology with using the fine parameter of the failures flow is described. The comparison of non failure probability and failures flow is carried out. The calculation of these parameters in the practical example is shown too. (author)

Review of fuel element development for nuclear rocket engines

International Nuclear Information System (INIS)

Taub, J.M.

1975-06-01

The Los Alamos Scientific Laboratory (LASL) entered the nuclear propulsion field in 1955 and began work on all aspects of a nuclear propulsion program involving uranium-loaded graphite fuels, hydrogen propellant, and a target exhaust temperature of approximately 2500 0 C. A very extensive uranium-loaded graphite fuel element technology evolved from the program. Selection and composition of raw materials for the extrusion mix had to be coupled with heat treatment studies to give optimum element properties. The highly enriched uranium in the element was incorporated as UO 2 , pyrocarbon-coated UC 2 , or solid solution UC . ZrC particles. An extensive development program resulted in successful NbC or ZrC coatings on elements to withstand hydrogen corrosion at elevated temperatures. Hot gas, thermal shock, thermal stress, and NDT evaluation procedures were developed to monitor progress in preparation of elements with optimum properties. Final evaluation was made in reactor tests at NRDS. Aerojet-General, Westinghouse Astronuclear Laboratory, and the Oak Ridge Y-12 Plant of Union Carbide Nuclear Company entered the program in the early 1960's, and their activities paralleled those of LASL in fuel element development. (U.S.)

Nuclear fission and the transuranium elements

International Nuclear Information System (INIS)

Seaborg, G.T.

1989-02-01

Many of the transuranium elements are produced and isolated in large quantities through the use of neutrons furnished by nuclear fission reactions: plutonium (atomic number 94) in ton quantities; neptunium (93), americium (95), and curium (96) in kilogram quantities; berkelium (97) in 100 milligram quantities; californium (98) in gram quantities; and einsteinium (99) in milligram quantities. Transuranium isotopes have found many practical applications---as nuclear fuel for the large-scale generation of electricity, as compact, long-lived power sources for use in space exploration, as means for diagnosis and treatment in the medical area, and as tools in numerous industrial processes. Of particular interest is the unusual chemistry and impact of these heaviest elements on the periodic table. This account will feature these aspects. 9 refs., 5 figs

Nuclear fission and the transuranium elements

Energy Technology Data Exchange (ETDEWEB)

Seaborg, G.T.

1989-02-01

Many of the transuranium elements are produced and isolated in large quantities through the use of neutrons furnished by nuclear fission reactions: plutonium (atomic number 94) in ton quantities; neptunium (93), americium (95), and curium (96) in kilogram quantities; berkelium (97) in 100 milligram quantities; californium (98) in gram quantities; and einsteinium (99) in milligram quantities. Transuranium isotopes have found many practical applications---as nuclear fuel for the large-scale generation of electricity, as compact, long-lived power sources for use in space exploration, as means for diagnosis and treatment in the medical area, and as tools in numerous industrial processes. Of particular interest is the unusual chemistry and impact of these heaviest elements on the periodic table. This account will feature these aspects. 9 refs., 5 figs.

Fundamental aspects of nuclear reactor fuel elements

Energy Technology Data Exchange (ETDEWEB)

Olander, D.R.

1976-01-01

The book presented is designed to function both as a text for first-year graduate courses in nuclear materials and as a reference for workers involved in the materials design and performance aspects of nuclear power plants. The contents are arranged under the following chapter headings: statistical thermodynamics, thermal properties of solids, crystal structures, cohesive energy of solids, chemical equilibrium, point defects in solids, diffusion in solids, dislocations and grain boundaries, equation of state of UO/sub 2/, fuel element thermal performance, fuel chemistry, behavior of solid fission products in oxide fuel elements, swelling due to fission gases, pore migration and fuel restructuring kinetics, fission gas release, mechanical properties of UO/sub 2/, radiation damage, radiation effects in metals, interaction of sodium and stainless steel, modeling of the structural behavior of fuel elements and assemblies. (DG)

The Origin and Distribution of Heavy Elements in HCG 62

Science.gov (United States)

Vrtilek, Jan; Lavoie, Anthony R. (Technical Monitor)

2000-01-01

We present recent data on the compact group HCG 62 taken with AXAF CCD Imaging Spectrometer-S (ACIS-S) on Chandra. The sparseness of groups and their relatively simple dynamical history allow the properties of the Intergalatic Medium (IGM) to be more directly related to galaxy evolution than may be possible in clusters, and their lower gas temperatures produce strong lines from a broader range of elements than is the case in hotter clusters. This observation exploits the high X-ray brightness of HCG 62 to determine accurately the abundances of heavy elements as a function of position in the group, to test whether abundance variations are associated with individual galaxies, and to trace the origin of the enrichment.

Nuclear-physical methods of investigation of an element composition in samples of soils and plants

International Nuclear Information System (INIS)

Hushmurodov, Sh.; Botaev, N.

2002-01-01

Soil (ground) and vegetative covers of the Earth are one of the most responsive and specific parts of the biosphere with respect to pollution. A proper control after them is of fundamental importance in creating and protecting optical surrounding. Analysis of soils and plants is a necessary and important stage in the process of investigation of microelements' migration in biogeochemical cycles. For this purpose we studied some reserved terrains of Uzbekistan to reveal a level of their contamination by heavy metals, as well as to find out typical and territorial singularities in accumulation of a number of elements by soils and plants. In order to decrease an influence of systematic errors, and to obtain more precise and reliable data, we carried out the element analysis of the samples by different methods, such as gamma-activation analysis, neutron-activation analysis, X-ray spectral analysis, and X-ray fluorescent analysis. As a result of our investigations we have obtained rather great information, which can be used in future to estimate the conditions of the surrounding nature. The investigations allowed us to determine the content of about 40 elements, as well as to show that the data, obtained by different nuclear-physical methods, are in rather good agreement. A reproducibility of the results of the methods, determined in control measurements, depends on the concentration of the analyzed elements, and is equal to 10-35 %. A comparison of the obtained data allowed us to reveal some singularities in element composition of the investigated samples depending on their type and territorial factor. It has been revealed that the data, obtained by different methods, are in rather good agreement. Our investigations allowed us to find out a series of regularities and singularities in accumulation of elements in plants, as well as to show the possibility of using nuclear-physical methods in such investigations

Nuclear data evaluation for medium and heavy nuclei

International Nuclear Information System (INIS)

Mizumoto, Motoharu

1988-01-01

Present status of nuclear data evaluation works for medium and heavy nuclei is described in this paper. These data are being prepared for JENDL-3 (Japanese Evaluated Nuclear Data Library-Version 3). At present, about a half of the data files, which are expected to be stored in the final library, has been brought into a temporary library called JENDL-3T. The remaining works and additional revisions are still needed to be made in order to finalize the data library as JENDL-3. Special emphases have been put on the high energy neutron data for which the previous JENDL-2 had some inadequacies, and gamma-ray production cross sections have been newly evaluated. Systematic and consistent evaluations have been intended for the new evaluations. (author)

G.N. Florov Laboratory of Nuclear Reactions, history and the present day

International Nuclear Information System (INIS)

Szmider, J.

1996-01-01

The scientific activity and review of results attained at Florov Nuclear Reactions Laboratory of the Joined Institute of Nuclear Research, Dubna, have been presented in historical order. Especially the heavy ion cyclotron use for synthesis of new super-heavy elements as well as investigations of their physical and chemical properties have been shown. 1 fig

Nuclear reactor fuel elements

International Nuclear Information System (INIS)

Butterfield, C.E.; Waite, E.

1982-01-01

A nuclear reactor fuel element comprising a column of vibration compacted fuel which is retained in consolidated condition by a thimble shaped plug. The plug is wedged into gripping engagement with the wall of the sheath by a wedge. The wedge material has a lower coefficient of expansion than the sheath material so that at reactor operating temperature the retainer can relax sufficient to accommodate thermal expansion of the column of fuel. (author)

Vented nuclear fuel element

International Nuclear Information System (INIS)

Oguma, M.; Hirose, Y.

1976-01-01

A description is given of a vented nuclear fuel element having a plenum for accumulation of fission product gases and plug means for delaying the release of the fission product gases from the plenum, the plug means comprising a first porous body wettable with a liquid metal and a second porous body non-wettable with the liquid metal, the first porous body being impregnated with the liquid metal and in contact with the liquid metal

Nuclear fuel element end fitting

International Nuclear Information System (INIS)

Jabsen, F.S.

1979-01-01

A typical embodiment of the invention has an array of sockets that are welded to the intersections of the plates that form the upper and lower end fittings of a nuclear reactor fuel element. The sockets, which are generally cylindrical in shape, are oriented in directions that enable the longitudinal axes of the sockets to align with the longitudinal axes of the fuel rods that are received in the respective sockets. Detents impressed in the surfaces of the sockets engage mating grooves that are formed in the ends of the fuel rods to provide for the structural integrity of the fuel element

Theory of nuclear reactions, with applications to heavy ion scattering reactions

International Nuclear Information System (INIS)

Youssef, M.S.A.

1981-01-01

Nuclear science to day, has gained its stature through the pioneer work of both theorists and experimentalists within its two main divisions, Nuclear Reaction and Nuclear Structure theories. Our main interest in this theoretical work in nuclear reaction theory is focused on three topics, come under the headings of three parts which are the constituents of the present paper. Part 1 is concerned with ''Contributions to the theory of Threshold phenomena in nuclear reactions; cluster threshold states in heavy ion reactions''. Part II is devoted to ''Hermiticity of the Laplacian operator, R-matrix theories and direct interaction theory'', while part xII is ascribed to ''Heavy ion transfer reactions and scattering''. The aforementioned selected topics are the backbones of this thesis, which starts with general introduction giving a brief account about the material included in. In each part, investiqations are given in an extended manner through several chapters. Finally, the thesis is ended eith the chapter on ''General Discussions and Conclusions''. Appendices, references, and figure captions are found at the end of each part, the matter which we believe to facilitate much the reading through of the thesis. The first two parts are based (to some extent) on the same formal background (R-matrix, Kapur-Peierls-theories) and they converge to solve some physical problems originating from flux conservation laws in nuclear reactions, while the third part is indirect related to the first two; in principle it joins the other two parts under computational aspects. All of them after all, form the solidarity of the material included in the thesis. (author)

MODERATOR ELEMENTS FOR UNIFORM POWER NUCLEAR REACTOR

Science.gov (United States)

Balent, R.

1963-03-12

This patent describes a method of obtaining a flatter flux and more uniform power generation across the core of a nuclear reactor. The method comprises using moderator elements having differing moderating strength. The elements have an increasing amount of the better moderating material as a function of radial and/or axial distance from the reactor core center. (AEC)

Nuclear fuel element recovery using PEDSCO RMI Unit

International Nuclear Information System (INIS)

Martin, D.G.; Pedersen, B.V.

1984-01-01

In September 1982, a PEDSCO Remote Mobile Investigation Unit was used to recover damaged irradiated fuel elements from a fueling machine and trolley deck at Bruce Nuclear Generating Station 'A'. This Canadian-made remote controlled vehicle was originally designed for explosive ordinance disposal by law enforcement agencies. This paper describes its adaptation to nuclear service and its first mission, within a nuclear facility

Proceedings of the 12. International Symposium on Nuclear Physics - Heavy-Ion Collisions and Nuclear Fission - organized by the Technical University of Dresden, November 22-26, 1982 in Gaussig (GDR)

International Nuclear Information System (INIS)

Reif, R.; Teichert, J.

1982-12-01

The following problems in experimental and theoretical investigations of heavy-ion reactions and the dynamics of nuclear fission processes are discussed: (1) emission of fast light particles in heavy-ion collisions, preequilibrium effects; (2) dynamics of deep inelastic heavy-ion reactions; (3) selected topics in quasi-elastic heavy-ion collisions; and (4) collective transport theory for fission, cross sections and neutron spectra of fission. Problems of neutron induced reactions and nuclear data evaluation are also covered. (author)

Evaluation of electon and nuclear bremsstrahlung in heavy ion collisions

International Nuclear Information System (INIS)

Gippner, P.

1975-01-01

The detection of quasimolecular X-ray continua provides the possibility of investigating the electron shells of quasimolecules transiently formed during adiabatic heavy ion-atomic collision. The contribution of the electron and nuclear bremsstrahlung to quasimolecular X-ray continua observed in bombarding various targets with 65 and 96 MeV Nb ions were estimated

A novel approach to the island of stability of super-heavy elements search

Directory of Open Access Journals (Sweden)

Wieloch A.

2016-01-01

Full Text Available It is expected that the cross section for super-heavy nuclei production of Z > 118 is dropping into the region of tens of femto barns. This creates a serious limitation for the complete fusion technique that is used so far. Moreover, the available combinations of the neutron to proton ratio of stable projectiles and targets are quite limited and it can be difficult to reach the island of stability of super heavy elements using complete fusion reactions with stable projectiles. In this context, a new experimental investigation of mechanisms other than complete fusion of heavy nuclei and a novel experimental technique are invented for our search of super- and hyper-nuclei. This contribution is focused on that technique.

Respectives of heavy ion physics in JINR

International Nuclear Information System (INIS)

Flerov, G.N.

1983-01-01

Perspectives of heavy ion physics in JINR are discussed. The main attention is paid to directions that are connected with the application of intensive beams of U-400 cyclotron. Experiments into studying stability limits of heavy atomic nuclei are considered. The possibility of using beams of heavy ions in applied fields, particularly for the production of very thin nuclear filters is noted. Prospects of synthesis of superheavy elements (SHE) and SHE search in nature are also considered. The data on the events of spontaneous fission found in meteorite and hydrotherms and the data on lengths of tracks in olivines from meteorite prove the possibility of obtaining evidences of SHE existence in nature

Dynamics of nuclear fission and heavy-ion reactions

International Nuclear Information System (INIS)

Nix, J.R.; Sierk, A.J.

1979-01-01

Large-amplitude collective motion in fission and heavy-ion reactions is studied by solving classical equations of motion for the time evolution of the nuclear shape. In the nuclear potential energy of deformation, the generalized surface energy was calculated by means of a double volume integral of a Yukawa-plus-exponential function, which was obtained by requiring that two semi-infinite slabs of constant-density nuclear matter have minimum energy at zero separation. The collective kinetic energy is calculated for nuclear flow that is a superposition of incompressible, nearly irrotational collective-shape motion and rigid-body rotation. Nuclear dissipation is included by means of the Rayleigh dissipation function, which depends upon the physical mechanism that converts collective energy into internal energy. For both ordinary two-body viscosity and a combined wall and window one-body dissipation, fission-fragment kinetic energies are calculated for the fission of nuclei throughout the periodic table and compare with experimental results. Finally, the one-body dynamics of nucleons inside a cylinder colliding with a moving piston is explicitly studied by solving exactly the collisionless Boltzmann equation for the distribution function. By examining the relative phases of the pressure at the piston and the piston's velocity, a dissipative force and an elastic restoring force can be separately identified. 9 references

Atomic data for heavy element impurities in fusion reactors. Summary report of the final research coordination meeting

International Nuclear Information System (INIS)

Clark, R.E.H.

2009-04-01

Eleven experts on the properties of heavy elements of relevance to fusion energy research attended the final Research Coordination Meeting (RCM) on Data for Heavy Element Impurities in Fusion Reactors, held at IAEA Headquarters on 4-6 March 2009. Participants summarized their accomplishments with respect to the revised work plan formulated at the second RCM. The overall work plan for the CRP was assessed and reviewed in detail, and achievements were noted. Discussions, conclusions and recommendations of the RCM are briefly described in this report. (author)

Nuclear data needs for studying the astrophysical r- and p-processes

International Nuclear Information System (INIS)

Howard, W.M.; Meyer, B.S.

1991-09-01

Recent advances in understanding the astrophysical sites for the r-, p- and 3-processes has led to an increased understanding of the nuclear physics requires to calculate the thermonuclear origin of the heavy elements in nature. We review specific examples of where nuclear information obtained with Radioactive Nuclear Beams can greatly help our understanding of the thermonuclear origin of the elements in nature. 4 figs

Single cell elemental analysis using nuclear microscopy

International Nuclear Information System (INIS)

Ren, M.Q.; Thong, P.S.P.; Kara, U.; Watt, F.

1999-01-01

The use of Particle Induced X-ray Emission (PIXE), Rutherford Backscattering Spectrometry (RBS) and Scanning Transmission Ion Microscopy (STIM) to provide quantitative elemental analysis of single cells is an area which has high potential, particularly when the trace elements such as Ca, Fe, Zn and Cu can be monitored. We describe the methodology of sample preparation for two cell types, the procedures of cell imaging using STIM, and the quantitative elemental analysis of single cells using RBS and PIXE. Recent work on single cells at the Nuclear Microscopy Research Centre,National University of Singapore has centred around two research areas: (a) Apoptosis (programmed cell death), which has been recently implicated in a wide range of pathological conditions such as cancer, Parkinson's disease etc, and (b) Malaria (infection of red blood cells by the malaria parasite). Firstly we present results on the elemental analysis of human Chang liver cells (ATTCC CCL 13) where vanadium ions were used to trigger apoptosis, and demonstrate that nuclear microscopy has the capability of monitoring vanadium loading within individual cells. Secondly we present the results of elemental changes taking place in individual mouse red blood cells which have been infected with the malaria parasite and treated with the anti-malaria drug Qinghaosu (QHS)

An unmet challenge: consideration of heavy fouling in severe accident analyses

Energy Technology Data Exchange (ETDEWEB)

Robert H Leyse [CEO Inz, Inc., PO BOX 2850, Sun Valley, ID 83353 (United States)

2005-07-01

Full text of publication follows: The impact of heavy fouling of fuel elements in light water cooled and moderated nuclear reactors has not been considered in the analysis of severe accidents such as Reactivity Insertion Accidents and Loss of Coolant Accidents. This is the case even though operation of nuclear power reactors with significant fouling deposits is commonplace. Fouling deposits have substantial thermal resistance. This has led to fuel element failures in several instances as the zirconium alloy cladding has failed due to high temperature corrosion. Although the details of current fouling have not been disclosed, in one case the deposits have been described as, 'unusually heavy' which induced the corrosion by thermally insulating the fuel rods' and 'rods that failed had heavy crud with clumpy formations'. Such heavy clumpy fouling is complex with substantial thermal resistance. Relatively straightforward fouling at the Experimental Boiling Water Reactor was classified in terms of the thickness and the thermal conductivity.7 Thickness of the fouling was 0.013 cm, the thermal conductivity was 0.008 W/cm-C; thus the heat transfer coefficient was 0.6 W/(cm{sup 2})(C). The peak heat flux in today's large light water reactors is in the range of 150 W/cm{sup 2} and the temperature gradient for EBWR-type fouling would be 250 C. However, the effective heat transfer coefficient of the heavy, clumpy fouling in today's reactors is likely substantially less than the EBWR case. Clearly, the heat transfer characteristics are vastly degraded in contrast to clean as-built cores. The challenge for the licensees of nuclear power reactors is to produce thorough evaluations of the impact of heavy fouling on severe accidents. The findings are needed for the accurate licensing of water-cooled nuclear reactors. The United States Nuclear Regulatory Commission has evaluated two related Petitions for Rulemaking that have been initiated by the

An unmet challenge: consideration of heavy fouling in severe accident analyses

International Nuclear Information System (INIS)

Robert H Leyse

2005-01-01

Full text of publication follows: The impact of heavy fouling of fuel elements in light water cooled and moderated nuclear reactors has not been considered in the analysis of severe accidents such as Reactivity Insertion Accidents and Loss of Coolant Accidents. This is the case even though operation of nuclear power reactors with significant fouling deposits is commonplace. Fouling deposits have substantial thermal resistance. This has led to fuel element failures in several instances as the zirconium alloy cladding has failed due to high temperature corrosion. Although the details of current fouling have not been disclosed, in one case the deposits have been described as, 'unusually heavy' which induced the corrosion by thermally insulating the fuel rods' and 'rods that failed had heavy crud with clumpy formations'. Such heavy clumpy fouling is complex with substantial thermal resistance. Relatively straightforward fouling at the Experimental Boiling Water Reactor was classified in terms of the thickness and the thermal conductivity.7 Thickness of the fouling was 0.013 cm, the thermal conductivity was 0.008 W/cm-C; thus the heat transfer coefficient was 0.6 W/(cm 2 )(C). The peak heat flux in today's large light water reactors is in the range of 150 W/cm 2 and the temperature gradient for EBWR-type fouling would be 250 C. However, the effective heat transfer coefficient of the heavy, clumpy fouling in today's reactors is likely substantially less than the EBWR case. Clearly, the heat transfer characteristics are vastly degraded in contrast to clean as-built cores. The challenge for the licensees of nuclear power reactors is to produce thorough evaluations of the impact of heavy fouling on severe accidents. The findings are needed for the accurate licensing of water-cooled nuclear reactors. The United States Nuclear Regulatory Commission has evaluated two related Petitions for Rulemaking that have been initiated by the author regarding these matters. Currently the

Considerations concerning the physics of nuclear matter under extreme conditions and an accelerator for relativistic heavy ions

International Nuclear Information System (INIS)

Blasche, K.; Bock, R.; Franzke, B.; Greiner, W.; Gutbrod, H.H.; Povh, B.; Schmelzer, C.; Stock, R.

1977-01-01

The future problems of heavy-ion physics in the 10 GeV/U range are dealt with: the dynamics of relativistic nuclear collisions, phase transitions, nuclear matter, quantum electrodynamics of extremely strong fields, and astrophysical aspects. In the second part, the project of a heavy-ion accelerator in the 10 GeV/U range to be coupled to the present GSI UNILAC accelerator is discussed. (WL) [de

Nuclear reactions and synthesis of new transuranium species

International Nuclear Information System (INIS)

Seaborg, G.T.

1983-01-01

In this short review, I shall describe the special aspects of heavy ion nuclear reaction mechanisms operative in the transuranium region, the role of new techniques, possible nuclear reactions for the production of additional transuranium elements and nuclear species and the importance of work in this region for the development of nuclear models and theoretical concepts. This discussion should make it clear that a continuing supply of leements and isotopes, some fo them relatively short-lived, produced by the HFIR-TRU facilities, will be a requirement for future synthesis of new elements and isotopes

On elastic structural elements for nuclear reactors

International Nuclear Information System (INIS)

Povolo, F.

1978-03-01

The in-pile stress-relaxation behaviour of materials usually employed for the elastic structural elements, in nuclear reactors, is critically reviewed and the results are compared with those obtained in commercial zirconium alloys irradiated under similar conditions. Finally, it is shown that, under certain conditions, some zirconium alloys may be used as an alternative material for these structural elements. (orig.) [de

Process to separate transuranic elements from nuclear waste

Science.gov (United States)

Johnson, T.R.; Ackerman, J.P.; Tomczuk, Z.; Fischer, D.F.

1989-03-21

A process is described for removing transuranic elements from a waste chloride electrolytic salt containing transuranic elements in addition to rare earth and other fission product elements so the salt waste may be disposed of more easily and the valuable transuranic elements may be recovered for reuse. The salt is contacted with a cadmium-uranium alloy which selectively extracts the transuranic elements from the salt. The waste salt is generated during the reprocessing of nuclear fuel associated with the Integral Fast Reactor (IFR). 2 figs.

Process to separate transuranic elements from nuclear waste

International Nuclear Information System (INIS)

Johnson, T.R.; Ackerman, J.P.; Tomczuk, Z.; Fischer, D.F.

1989-01-01

A process is described for removing transuranic elements from a waste chloride electrolytic salt containing transuranic elements in addition to rare earth and other fission product elements so the salt waste may be disposed of more easily and the valuable transuranic elements may be recovered for reuse. The salt is contacted with a cadmium-uranium alloy which selectively extracts the transuranic elements from the salt. The waste salt is generated during the reprocessing of nuclear fuel associated with the Integral Fast Reactor (IFR). 2 figs

The WWER fuel element safety research under the design and heavy accident imitation on the 'PARAMETR' stand

International Nuclear Information System (INIS)

Deniskin, V.P.; Nalivaev, V.I.; Parshin, N. Ya.; Fedik, I.I.

2000-01-01

Analysis of fuel element behavior in the course of the design and heavy accidents is the component of reactor facility safety prevention. Many tasks of fuel element behavior research may be solved with the help of thermophysical stands. One of such stands implemented in 1991 was thermophysical stand 'PARAMETER'.Several experiments on model assemblies chiefly imitating both heavy accident and design basic accident have already been conducted in 'PARAMETER' stand. There were obtained data about fuel claddings seal failure and deformation condition. In particular it was defined that seal failure of all fuel claddings occurs on stage of fuel element warming, in temperature range (770-900) degree celsius and almost does not depend on inner pressure level

Development of nuclear standard filter elements for PWR plant

International Nuclear Information System (INIS)

Weng Minghui; Wu Jidong; Gu Xiuzhang; Zhang Jinghua

1988-11-01

Model FRX-5 and FRX-10 nuclear standard filter elements are used for the fluid clarification of the chemical and volume control system (CVCS), boron recycle system (BRS), spent fuel pit cooling system (SFPCS) and steam generator blowdown system (SGBS) in Qinshan Nuclear Power Plant. The radioactive contaminant, fragment of resin and impurity are collected by these filter elements, The core of filter elements consists of polypropylene frames and paper filter medium bonded by resin. A variety of filter papers are tested for optimization. The flow rate and comprehensive performance have been measured in the simulation condition. The results showed that the performance and lifetime have met the designing requirements. The advantages of the filter elements are simple in manufacturing, less expense and facilities for waste-disposal. At present, some of filter elements have been produced and put in operation

The fabrication of nuclear fuel elements in Mexico

International Nuclear Information System (INIS)

Guerrero Morillo, H.L.

1977-01-01

The situation of nuclear electricity generation in Mexico in 1976 is described: two nuclear reactors were under construction but no definite programme on the type and start-up dates for the next power plants existed. However, the existence of a general plan on nuclear power plants is mentioned, which, according to the latest estimates, will provide 10,000MW installed by 1990. The national intention, as laid down in an appropriate Law, is to supply domestic nuclear fuel to the power reactors operating in the country, starting with the first reloading of the two BWRs at the first national station in Laguna Verde, required at the end of 1981 and 1982, respectively. Before this can be achieved and to provide the relatively small amounts of fuel elements for the two reactors, Mexico must adopt a strategy of fuel elements fabrication. The two main options are analysed: (1) to delay local fabrication until a national nuclear programme has been defined, meanwhile purchasing abroad the necessary initial cores and refuelling; (2) to start local fabrication of fuel elements as soon as possible in order to provide the first refuelling of the first unit of Laguna Verde, confronting the economic risks of such a decision with the advantages of immediate action. Both options are analysed in detail, comparing them especially from the economic point of view. Current information from potential licensors for design and manufacture are used in the analysis. (author)

Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range.

Science.gov (United States)

Juárez, Andrea; Arribére, María A; Arcagni, Marina; Williams, Natalia; Rizzo, Andrea; Ribeiro Guevara, Sergio

2016-09-01

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions

OpenAIRE

Nefiodov, A. V.; Plunien, G.; Soff, G.

2002-01-01

The influence of nuclear polarization on the bound-electron $g$ factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron $g$ factor in highly charged ions.

Nuclear-polarization correction to the bound-electron g factor in heavy hydrogenlike ions.

Science.gov (United States)

Nefiodov, A V; Plunien, G; Soff, G

2002-08-19

The influence of nuclear polarization on the bound-electron g factor in heavy hydrogenlike ions is investigated. Numerical calculations are performed for the K- and L-shell electrons taking into account the dominant virtual nuclear excitations. This determines the ultimate limit for tests of QED utilizing measurements of the bound-electron g factor in highly charged ions.

Heavy density concrete for nuclear radiation shielding and power stations: [Part]3

International Nuclear Information System (INIS)

Singha Roy, P.K.

1987-01-01

This article is the third part of the paper entitled 'Heavy density concrete for nuclear radiation shielding and power stations'. Specific considerations relevant to natural but manufactured heavy aggregates like haematite used in India are briefly discussed. They include water-cement ratio, strength versus water-cement ratio, mix design strength and aggregate grading. Some typical mix proportions in haematite concretes used in India are given. Equipment for heavy density concrete is mentioned. Quality control methods and tests for heavy density concrete are described under the heading: type and chemical composition of the rock, specific gravity and surface absorption of the aggregates, grading of aggregates, cement, batching, mixing, compressive strength, and density. Construction aspects such as form work, placement, vibration, finishing, and temperature control are discussed. Finally it is pointed out that for optimising the design and economy of heavy density concrete, it is necessary to carry out country-wide survey of suitable materials, to study their properties, suitability and effectiveness in shielding radiation. (M.G.B.)

Physics and technology of nuclear materials

International Nuclear Information System (INIS)

Ursu, I.

1985-01-01

The subject is covered in chapters, entitled; elements of nuclear reactor physics; structure and properties of materials (including radiation effects); fuel materials (uranium, plutonium, thorium); structural materials (including - aluminium, zirconium, stainless steels, ferritic steels, magnesium alloys, neutron irradiation induced changes in the mechanical properties of structural materials); moderator materials (including - nuclear graphite, natural (light) water, heavy water, beryllium, metal hydrides); materials for reactor reactivity control; coolant materials; shielding materials; nuclear fuel elements; nuclear material recovery from irradiated fuel and recycling; quality control of nuclear materials; materials for fusion reactors (thermonuclear fusion reaction, physical processes in fusion reactors, fuel materials, materials for blanket and cooling system, structural materials, materials for magnetic devices, specific problems of material irradiation). (U.K.)

Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Phase II Upgrade Activities

Science.gov (United States)

Emrich, William J.; Moran, Robert P.; Pearson, J. Bose

2013-01-01

To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). This device can simulate the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner so as to accurately reproduce the temperatures and heat fluxes which would normally occur as a result of nuclear fission and would be exposed to flowing hydrogen. Initial testing of a somewhat prototypical fuel element has been successfully performed in NTREES and the facility has now been shutdown to allow for an extensive reconfiguration of the facility which will result in a significant upgrade in its capabilities. Keywords: Nuclear Thermal Propulsion, Simulator

Porous nuclear fuel element for high-temperature gas-cooled nuclear reactors

Science.gov (United States)

Youchison, Dennis L [Albuquerque, NM; Williams, Brian E [Pacoima, CA; Benander, Robert E [Pacoima, CA

2011-03-01

Porous nuclear fuel elements for use in advanced high temperature gas-cooled nuclear reactors (HTGR's), and to processes for fabricating them. Advanced uranium bi-carbide, uranium tri-carbide and uranium carbonitride nuclear fuels can be used. These fuels have high melting temperatures, high thermal conductivity, and high resistance to erosion by hot hydrogen gas. Tri-carbide fuels, such as (U,Zr,Nb)C, can be fabricated using chemical vapor infiltration (CVI) to simultaneously deposit each of the three separate carbides, e.g., UC, ZrC, and NbC in a single CVI step. By using CVI, the nuclear fuel may be deposited inside of a highly porous skeletal structure made of, for example, reticulated vitreous carbon foam.

Shock buffer for nuclear control element assembly

International Nuclear Information System (INIS)

Bevilacqua, F.

1977-01-01

A shock buffer for a control element assembly in a nuclear reactor is described, comprising a piston and a cylinder. The piston is affixed to and extends upward from the control rod guide structure; the cylinder is supported by the upper portion of the control element assembly and is vertically oriented with open end downward for receiving the piston. Coolant liquid normally has free access to the cylinder. The piston displaces liquid from the cylinder when inserted, thereby decelerating the control element assembly near its lower extent of travel. (LL)

Nuclear reactor fuel element assemblies

International Nuclear Information System (INIS)

Raven, L.F.

1975-01-01

A spacer grid for a nuclear fuel element comprises a plurality of cojointed cylindrical ferrules adapted to receive a nuclear fuel pin. Each ferrule has a pair of circumferentially spaced rigid stop members extending inside the ferrule and a spring locating member attached to the ferrule and also extending from the ferrule wall inwardly thereof at such a circumferential spacing relative to the rigid stop members that the line of action of the spring locating member passes in opposition to and between the rigid stop members which lie in the same diametric plane. At least some of the cylindrical ferrules have one rim shaped to promote turbulence in fluid flowing through the grid. (Official Gazette)

Improved moulding material for addition to nuclear fuel particles to produce nuclear fuel elements

International Nuclear Information System (INIS)

Miertschin, G.N.; Leary, D.F.

1976-01-01

A suggestion is made to improve the moulding materials used to produce carbon-contained nuclear fuel particles by a coke-reducing added substance. The nuclear fuel particles are meant for the formation of fuel elements for gas-cooled high-temperature nuclear reactors. The moulding materials are above all for the formation of coated particles which are burnt in situ in nuclear fuel element chambers out of 'green' nuclear fuel bodies. The added substance improves the shape stability of the particles forming and prevents a stiding or bridge formation between the particles or with the surrounding walls. The following are named as added substances: 1) Polystyrene and styrene-butadiene-Co polymers (mol. wt. between 5oo and 1,000,000), 2) aromatic compounds (mol. wt. 75 to 300), 3) saturated hydrocarbon polymers (mol. wt. 5,000 to 1,000,000). Additional release agents further improve the properties in the same direction (e.g. alcohols, fatty acids, amines). (orig.) [de

Nuclear Physics Laboratory annual report

International Nuclear Information System (INIS)

Trainor, T.A.; Weitkamp, W.G.

1985-04-01

Progress is reported in these areas: nuclear physics relevant to astrophysics and cosmology; nuclear structure of 14 N; the Cabibbo angle in Fermi matrix elements of high j states; giant resonances; heavy ion reactions; 0 + - 0 - isoscalar parity mixing in 14 N; parity mixing in hydrogen and deuterium; medium energy physics; and accelerator mass spectrometry. Accelerators and ion sources, nuclear instrumentation, and computer systems at the university are discussed, including the booster linac project

The determination of sulfur and some heavy elements in the coke

International Nuclear Information System (INIS)

Ma'rouf, M.

2003-01-01

The content of free sulfur and some heavy elements in the coke resulting from the residua of oil industry was determined bu using various technical analytical methods. The flame technique of atomic absorption FAAS was used to identify lead, copper, zinc, chromium, VGA-AAS and determine arsenic and selenium, CV-AAS to the determination of mercury. As for sulfur, it was determined by using the total oxidation method at high temperatures (1100 C 0 ). The IR indicator was used for further determination. The relative standard deviation in the determination of sulfur did not exceed the limits of 0.01 and 0.02, compared to the determination of other elements by using the atomic absorption method. (Author)

Damper mechanism for nuclear reactor control elements

International Nuclear Information System (INIS)

Taft, W.E.

1976-01-01

A damper mechanism which provides a nuclear reactor control element decelerating function at the end of the scram stroke is described. The total damping function is produced by the combination of two assemblies, which operate in sequence. First, a tapered dashram assembly decelerates the control element to a lower velocity, after which a spring hydraulic damper assembly takes over to complete the final damping. 3 claims, 2 figures

Studies on Elemental Contents of Some Biological and Environmental Materials Using Nuclear And Atomic Techniques

International Nuclear Information System (INIS)

Abd-El Aziz, W.M.M.

2013-01-01

The elemental concentration values of 31 elements in the fertilizer samples, have been determined by applying a sensitive nondestructive analytical techniques such as INAA. It has also shown enough sensitivity to determine the concentrations of several trace and rare earth elements, The concentration values of elements were compared with the corresponding elements obtained by the ICP-MS and XRF techniques, for the same samples. Phosphorus fertilizers contain varying amounts of heavy metals and other rare earth elements as contaminants from either phosphate rock ores or other ingredients used in the phosphate fertilizer industry. As some heavy metals are potentially harmful to human health, attention is being given to its avenues of entry into the human food chain. Uptake of such elements by plants consumed directly or indirectly by humans is one avenue of entry, so the effects of heavy metal contaminants in phosphate fertilizers are of concern. Commercial fertilizers have been used for decades and will probably continue to be used for many decades to come. Hence, even low annual accumulations may finally build up undesired concentrations in soil, especially where fertilizers with high heavy metal or rare earth element concentrations are used.Thus, a total of three synthetic and natural eye-liner samples of known origin that are commercially available in the Egyptian market were analyzed using Energy Dispersive X-ray (EDX), Atomic Absorption Mass Spectroscopy (AA-MS) and elemental analysis using Thermal Neutron Activation Technique (TNAT) for the natural one in powder form. It was found that lead (>86%) represents the main hazardous element in the natural eye-liner from African sources. Aluminum and Antimony were also found in the later sample in considerable concentration 0.92% and 0.71% respectively. For the synthetic two samples from French and American sources, the major hazardous element found to be Carbon in high concentration 94% and 52% respectively. The

Superheavy elements

CERN Document Server

Hofmann, S

1999-01-01

The outstanding aim of experimental investigations of heavy nuclei is the exploration of spherical 'SuperHeavy Elements' (SHEs). On the basis of the nuclear shell model, the next double magic shell-closure beyond sup 2 sup 0 sup 8 Pb is predicted at proton numbers between Z=114 and 126 and at neutron number N=184. All experimental efforts aiming at identifying SHEs (Z>=114) were negative so far. A highly sensitive search experiment was performed in November-December 1995 at SHIP. The isotope sup 2 sup 9 sup 0 116 produced by 'radiative capture' was searched for in the course of a 33 days irradiation of a sup 2 sup 0 sup 8 Pb target with sup 8 sup 2 Se projectiles, however, only cross-section limits were measured. Positive results were obtained in experiments searching for elements from 110 to 112 using cold fusion and the 1n evaporation channel. The produced isotopes were unambiguously identified by means of alpha-alpha correlations. Not fission, but alpha emission is the dominant decay mode. The measurement ...

Study of the Matrix Effect on the Plasma Characterization of Heavy Elements in Soil Sediments

Directory of Open Access Journals (Sweden)

Tawfik W.

2007-01-01

Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to perform a study of the matrix effect on the plasma characterization of soil sediment targets. The plasma is generated by focusing a pulsed Nd: YAG laser on the target in air at atmospheric pressure. The plasma emission spectrum was detected using a portable Echelle spectrometer (Mechelle 7500 — Multichannel Instruments, Stockholm, Sweden with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, and electron temperature. Four heavy elements V, Pb, Mn and Co were determined in the obtained spectra. The LTE and optically thin plasma conditions were verified for the produced plasma. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of the spectral lines of the heavy elements in the soil sediments. The electron temperature does not change with concentration. For environmental applications, the obtained results showed the capability of the proposed LIBS setup with the portable Mechelle 7500 spectrometer to be applied in-situ for real-time measurements of the variation of the matrix elemental composition of soil sediments by following up only a single element as a marker for the composition of the soil sediment without need of analysis of the other elements.

Elements of a nuclear criticality safety program

International Nuclear Information System (INIS)

Hopper, C.M.

1995-01-01

Nuclear criticality safety programs throughout the United States are quite successful, as compared with other safety disciplines, at protecting life and property, especially when regarded as a developing safety function with no historical perspective for the cause and effect of process nuclear criticality accidents before 1943. The programs evolved through self-imposed and regulatory-imposed incentives. They are the products of conscientious individuals, supportive corporations, obliged regulators, and intervenors (political, public, and private). The maturing of nuclear criticality safety programs throughout the United States has been spasmodic, with stability provided by the volunteer standards efforts within the American Nuclear Society. This presentation provides the status, relative to current needs, for nuclear criticality safety program elements that address organization of and assignments for nuclear criticality safety program responsibilities; personnel qualifications; and analytical capabilities for the technical definition of critical, subcritical, safety and operating limits, and program quality assurance

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

2004-01-01

Full text: In spite of reduced personnel the number of papers published and in press exceeded fifty, almost ten more than a year ago. Another good sign is the growing number of PhD students. The following short reports cover the three major domains of our scientific activities: nuclear, material and atomic physics. Nuclear physics: The structure of light nuclei was investigated, and studies of nuclear reactions induced by heavy ions were performed including experiments at the Heavy Ion Laboratory of Warsaw University. The experiments were carried out in collaboration with scientists from the Institute of Nuclear Research from Kiev, Ukraine. Proton induced reactions on zirconium were investigated theoretically by means of a multistep-direct model extended for the unbound particle - hole states. Good agreement with the experimental data was achieved. Isospin effects in multifragmentation of relativistic heavy ions were studied by the ALADIN Collaboration. Elements of a new generation detector PANDA were tested experimentally using a proton beam provided by the C-30 compact cyclotron at Swierk. Evidence of a narrow baryon state was found in a quasi - real photoproduction on the deuterium target by the HERMES Collaboration. Atomic physics: Ionisation of selected heavy elements by sulphur ions was investigated in collaboration with the Swietokrzyska Academy, Kielce. Materials research: Hydrogen release from ultrahigh molecular weight polythene was investigated by means of an α - particle beam from the Van de Graaff accelerator of our Department. Last but not least, many of our colleagues have been involved in education. Lectures on nuclear physics, accelerators, detectors used in nuclear research as well as nuclear methods applied in solid state studies for students from many high schools of Warsaw and for students of Warsaw University were given by Dr. Andrzej Korman and Dr. Lech Nowicki. Also, our Department made a significant contribution to the 7 th Science

Effects of heavy elements in the sludge conveyed by the 2011 tsunami on human health and the recovery of the marine ecosystem

Energy Technology Data Exchange (ETDEWEB)

Sera, K., E-mail: ksera@iwate-med.ac.jp [Cyclotron Research Center, Iwate Medical University, 348-58 Tomegamori, Takizawa 020-0173 (Japan); Goto, S.; Takahashi, C.; Saitoh, Y. [Takizawa Laboratory, Japan Radioisotope Association, 348-58 Tomegamori, Takizawa 020-0173 (Japan); Yamauchi, K. [Division of Pulmonary Medicine, Department of Internal Medicine, Iwate Medical University, 19-1 Uchimaru, Morioka 020-8505 (Japan)

2014-01-01

The 2011 tsunami not only caused significant damage, but also drew a large amount of sludge from the bottom of the sea. This may have exerted negative effects on human health. In order to evaluate changes in elemental concentrations in the body before and after the tsunami, we collected long hairs from victims of the disaster. Furthermore, sludge and plant samples were collected from three prefectures. The sludge samples on land were found to be still contaminated with heavy elements. The concentrations of heavy elements in the soils and plants gathered from the same tidelands decreased after one year. In hair analyses, no clear changes have been observed in heavy element concentrations measured before and after the tsunami. However, the concentration of some essential elements, such as Cu, Ca and Mg, showed a decreasing tendency after the tsunami.

Effects of heavy elements in the sludge conveyed by the 2011 tsunami on human health and the recovery of the marine ecosystem

International Nuclear Information System (INIS)

Sera, K.; Goto, S.; Takahashi, C.; Saitoh, Y.; Yamauchi, K.

2014-01-01

The 2011 tsunami not only caused significant damage, but also drew a large amount of sludge from the bottom of the sea. This may have exerted negative effects on human health. In order to evaluate changes in elemental concentrations in the body before and after the tsunami, we collected long hairs from victims of the disaster. Furthermore, sludge and plant samples were collected from three prefectures. The sludge samples on land were found to be still contaminated with heavy elements. The concentrations of heavy elements in the soils and plants gathered from the same tidelands decreased after one year. In hair analyses, no clear changes have been observed in heavy element concentrations measured before and after the tsunami. However, the concentration of some essential elements, such as Cu, Ca and Mg, showed a decreasing tendency after the tsunami

Electron-translation effects in heavy-ion scattering

International Nuclear Information System (INIS)

Heinz, U.; Greiner, W.; Mueller, B.

1981-01-01

The origin and importance of electron-translation effects within a molecular description of electronic excitations in heavy-ion collisions is investigated. First, a fully consistent quantum-mechanical description of the scattering process is developed; the electrons are described by relativistic molecular orbitals, while the nuclear motion is approximated nonrelativistically. Leaving the quantum-mechanical level by using the semiclassical approximation for the nuclear motion, a set of coupled differential equations for the occupation amplitudes of the molecular orbitals is derived. In these coupled-channel equations the spurious asymptotic dynamical couplings are corrected for by additional matrix elements stemming from the electron translation. Hence, a molecular description of electronic excitations in heavy-ion scattering has been achieved, which is free from the spurious asymptotic couplings of the conventional perturbated stationary-state approach. The importance of electron-translation effects for continuum electrons and positrons is investigated. To this end an algorithm for the description of continuum electrons is proposed, which for the first time should allow for the calculation of angular distributions for delta electrons. Finally, the practical consequences of electron-translation effects are studied by calculating the corrected coupling matrix elements for the Pb-Cm system and comparing the corresponding K-vacancy probabilities with conventional calculations. We critically discuss conventional methods for cutting off the coupling matrix elements in coupled-channel calculations

Nuclear structure and heavy-ion fusion

International Nuclear Information System (INIS)

Stokstad, R.G.

1980-10-01

A series of lectures is presented on experimental studies of heavy-ion fusion reactions with emphasis on the role of nuclear structure in the fusion mechanism. The experiments considered are of three types: the fusion of lighter heavy ions at subcoulomb energies is studied with in-beam γ-ray techniques; the subbarrier fusion of 16 O and 40 Ar with the isotopes of samarium is detected out of beam by x-radiation from delayed activity; and measurements at very high energies, again for the lighter ions, employ direct particle identification of evaporation residues. The experimental data are compared with predictions based on the fusion of two spheres with the only degree of freedom being the separation of the centers, and which interact via potentials that vary smoothly with changes in the mass and charge of the projectile and target. The data exhibit with the isotopes of samarium, a portion of these deviations can be understood in terms of the changing deformation of the target nucleus, but an additional degree of freedom such as neck formation appears necessary. The results on 10 B + 16 O and 12 C + 14 N → 26 Al at high bombarding energies indicate a maximum limiting angular momentum characteristic of the compound nucleus. At lower energies the nuclear structure of the colliding ion seems to affect strongly the cross section for fusion. Measurements made at subbarrier energies for a variety of projectile-target combinations in the 1p and 2s - 1d shell also indicate that the valence nucleons can affect the energy dependence for fusion. About half the systems studied so far have structureless excitation functions which follow a standard prediction. The other half exhibit large variations from this prediction. The possible importance of neutron transfer is discussed. The two-center shell model appears as a promising approach for gaining a qualitative understanding of these phenomena. 95 references, 52 figures, 1 table

Nuclear polarization study: new frontiers for tests of QED in heavy highly charged ions.

Science.gov (United States)

Volotka, Andrey V; Plunien, Günter

2014-07-11

A systematic investigation of the nuclear polarization effects in one- and few-electron heavy ions is presented. The nuclear polarization corrections in the zeroth and first orders in 1/Z are evaluated to the binding energies, the hyperfine splitting, and the bound-electron g factor. It is shown that the nuclear polarization contributions can be substantially canceled simultaneously with the rigid nuclear corrections. This allows for new prospects for probing the QED effects in a strong electromagnetic field and the determination of fundamental constants.

Integral nuclear fuel element assembly

International Nuclear Information System (INIS)

Schluderberg, D. C.

1985-01-01

An integral nuclear fuel element assembly utilizes longitudinally finned fuel pins. The continuous or interrupted fins of the fuel pins are brazed to fins of juxtaposed fuel pins or directly to the juxtaposed fuel pins or both. The integrally brazed fuel assembly is designed to satisfy the thermal and hydraulic requirements of a fuel assembly lattice having moderator to fuel atom ratios required to achieve high conversion and breeding ratios

Heavy element abundances of Nova Cygni 1975

International Nuclear Information System (INIS)

Ferland, G.J.; Shields, G.A.

1978-01-01

McDonald observations of the nebular phase of the outburst of Nova Cygni 1975 are analyzed to measure the abundances of several heavy elements. A new analytical procedure is used to derive the electron density and temperature from the emission line intensities of [O III], [Ne III], and He I observed between days 40 and 120. These physical conditions are used to derive the abundances. We find that Fe has approximately a solar abundance, whereas C, N, O, and Ne are enhanced by factors approx.20 to 100. The enhanced abundance of neon was theoretically unexpected.The derived physical conditions and line intensities are compared with predictions of an equilibrium photoionization model. The model successfully predicts the intensities of He I, [O III], and [Ne III]; but it underestimates the strength of [Ne V] and [Fe VII], which may originate in a mechanically heated ''subcoronal'' line region

Heavy gauge plates for nuclear application

International Nuclear Information System (INIS)

Cheviet, A.; Roux, J.-H.

1977-01-01

The production of energy from nuclear sources leads to the building of very large vessels working under pressure at elevated temperatures, requiring very thick steel plate (from 50 mm to 300 mm). The plates necessary for the production of these vessels have to be as large as possible in order to reduce the length of welds on the vessels. Those two requirements lead to the manufacture of heavy products from 10 to 80 tons unit weight. These products are special, because their fabrication requires very big facilities and also extremely high quality of the steel. The main points are: high cleanliness; properties as homogeneous as possible. The tests carried out on industrially produced plates (especially on a plate of 200 mm thick show the level of quality that can be reached [fr

Perspectives for nuclear structure research at GSI: from halo nuclei to superheavy elements

Energy Technology Data Exchange (ETDEWEB)

Muenzenberg, G.

1997-11-01

After a brief overview on recent advances in the investigation of nuclei at the driplines and the upper end of the nuclear table key issues of nuclear structure research as adressed by new theoretical developments will be discussed in context with new developments in heavy-ion accelerators and experimental techniques. (orig.)

Perspectives for nuclear structure research at GSI--from halo nuclei to superheavy elements

International Nuclear Information System (INIS)

Munzenberg, G.

1997-01-01

After a brief overview on recent advances in the investigation of nuclei at the drip lines and the upper end of the nuclear table key issues of nuclear structure research as addressed by new theoretical developments will be discussed in context with new developments in heavy-ion accelerators and experimental techniques

Concentration of elements in atmospheric aerosol in Bratislava

International Nuclear Information System (INIS)

Meresova, J.; Florek, M.; Holy, K.; Sykora, I.; Frontasyeva, M.V.; Pavlov, S.S.

2006-01-01

The concentrations of 41 chemical elements (heavy metals, rare earths, and actinides) were determined in atmospheric aerosol using nuclear and related analytical techniques. The sampling location in Bratislava (Slovak Republic). The main goal of this study is the quantification of the atmospheric pollution and its trend. The elemental content in filters was measured using instrumental neutron activation analysis at IBR-2 reactor in JINR Dubna and by atomic absorption spectrometry in Bratislava. The obtained results confirm the decreasing trend of pollution by most of the heavy metals in Bratislava atmosphere, and they are compared with the contents of pollutants in atmosphere of other cities. We determined also the composition of clear filter materials. (Authors)

Open heavy flavor and quarkonia measurements in heavy-ion collisions at RHIC

Directory of Open Access Journals (Sweden)

Bielcik Jaroslav

2014-04-01

Full Text Available The properties of the hot and dense nuclear matter produced at RHIC in heavy-ion collisions can be investigated in multiple ways by heavy flavor production. The STAR and PHENIX experiments have excellent capability to study both open heavy flavor and quarkonia. Heavy quarks are produced in early stage of the collisions and the mechanisms of their interaction with nuclear matter are not yet well understood. The open heavy flavor hadrons can be studied using electrons from their semileptonic decays or via direct reconstruction through their hadronic decay channels. The heavy quarkonia production is expected to be sequentially suppressed depending on the temperature of the produced nuclear matter. However, cold nuclear matter effects play an important role and have to be well understood. In this paper we report recent results from the RHIC heavyion program on non-photonic electrons, direct reconstruction of charm mesons, J/ψ as well as ϒ in p+p, d+Au and Au+Au collisions at √sNN = 200 GeV.

The development of reactor vessel internal heavy forging for 1000 MW pressurized-water reactor nuclear power plant

International Nuclear Information System (INIS)

Zhang Zhifeng; Chen Yongbo; Ding Xiuping; Zhang Lingfang

2012-01-01

This Paper introduced the development of Reactor Vessel Internal (RVI) heavy forgings for 1000 MW Pressurized Water Reactor (PWR) nuclear power plant, analyzed the manufacture difficulties and technical countermeasures. The testing result of the product indicated that the performance of RVI heavy forgings manufactured by Shanghai Heavy Machinery Plant Ld. (SHMP) is outstanding and entirely satisfy the technical requirements for RVI product. (authors)

Investigation of Nuclear Fragmentation in Relativistic Heavy Ion Collisions Using Plastic - Nuclear - Track Detectors

CERN Multimedia

2002-01-01

In this experiment CR39 plastic nuclear track detectors will be used which are sensitive to detect relativistic nuclear fragments with charges Z@$>$5. They will be analyzed using an automatic track measuring system which was developed at the University of Siegen.\\\\ \\\\ This allows to measure large quantities of tracks in these passive detectors and to perform high statistics experiments. We intend to measure cross sections for the production of nuclear fragments from heavy ion beams at the SPS. \\\\ \\\\ The energy independence of the cross sections predicted by the idea of limiting fragmentation will be tested at high energies. In exposures with different targets we plan to analyze the factorization of the fragmentation cross sections into a target depending factor and a factor depending on the beam particle and the fragment. The cross sections for one proton remov Coulomb dissociation. \\\\ \\\\ We plan to investigate Coulomb dissociation for different targets and different energies. Fragment and projectile charges ...

Development of a novel heavy element chemistry apparatus using the RIKEN gas-field recoil separator as a pre-separator

International Nuclear Information System (INIS)

Haba, H.; Morita, K.; Enomoto, S.; Morimoto, K.; Kaji, D.; Nagame, Yuichiro

2004-01-01

A new system was developed, that supplied the super-heavy element separated physically as the former steps to the chemical analysis devices such as a gas or liquid chromatographs. The gas jet transportation device was newly set up on the edge of existing accelerator research facilities in the Institute of Physical and Chemical Research linac building (GARIS). To conduct the chemical separation experiment of a super-heavy element of 112 in future a radioactive isotope of mercury of light homology elements was manufactured with a gas jet uniting type online multi-tracer manufacturing device. The adsorption chromatograph experiment to the gold was performed using this system. (H. Katsuta)

3D finite element analysis of a nuclear fuel rod with gap elements between the pellet and the cladding

International Nuclear Information System (INIS)

Kang, Chang-Hak; Lee, Sung-Uk; Yang, Dong-Yol; Kim, Hyo-Chan; Yang, Yong-Sik

2016-01-01

Nuclear fuel rods which comprises an important component of a nuclear power plant are composed of nuclear fuel and cladding. Simulating the nuclear fuel rod using a computer program is the universal method to verify its safety. The computer program used for this is called the fuel performance code. The main objective of this study is to simulate the nuclear fuel rod behavior considering the gap conductance using three-dimensional gap elements. Gap elements are used because, unlike other methods, this approach does not require special methods or other variables such as the Lagrange multiplier. In this work, a nuclear fuel rod has been simulated and the results are compared with the experimental results. (author)

Nuclear structure studies towards superheavy elements and perspectives with AGATA

International Nuclear Information System (INIS)

Korichi, A.

2005-01-01

A variety of theoretical approaches have been used to calculate the shell closure of spherical Super Heavy Elements (SHE) but the predictions of the location of the 'island of stability' vary from Z=114 to 120 and 126, with neutron numbers around N=172 or N=184 depending on the model employed. A deformed minimum around Z=108 and N=162 is predicted and an increase of the half-life of Hassium (Z=108) is experimentally observed when approaching the neutron number N=162. Super heavy nuclei are produced with very low cross-section (a few picobarns) and this makes their spectroscopic study impossible with today's beam intensities and detectors. However, important information can be obtained from the structure of mid-shell deformed nuclei (Z∼104) where selected single particle orbitals, which lie close to the spherical shell gap in SHE, are close to the Fermi level. The information will come from decay and in-beam spectroscopy. A promising area of progress, using the state-of-the art instruments, is represented by the observation of rotational gamma-ray transitions in No and Fm isotopes showing the deformed character of these nuclei. One of the objectives and focus of the nuclear structure community is related to the investigation of Single particle excitations beyond the N=152 neutron gap and collective properties of heavier systems towards Z∼104. The IN2P3-JINR collaboration has launched a project of electron and gamma-ray spectroscopy studies of heavy nuclei at the FLNR. This project benefits from the radioactive actinide targets uniquely available at Dubna and from the very intense stable beams provided by the U400 cyclotron. This offers a unique opportunity for the study of nuclei above Z=100 along an isotopic chain approaching N=162. In this contribution, the emphasis will be on the GABRIELA project and its issues. I will finally point out the perspectives with the new generation of gamma detectors such as AGATA

Double β-decay nuclear matrix elements and lepton conservation

International Nuclear Information System (INIS)

Vergados, J.D.

1976-01-01

The nuclear matrix elements involved in the double β-decay of 48 Ca, 130 Te, and 128 Te were calculated using realistic nuclear interactions and shell model nuclear wave functions. The double doorway state is not appreciably mixed in the ground state of the final nuclei. So the ground state transitions contain a small fraction of the sum rule. A lepton nonconservation parameter eta -4 was deduced

Ground test facilities for evaluating nuclear thermal propulsion engines and fuel elements

International Nuclear Information System (INIS)

Allen, G.C.; Beck, D.F.; Harmon, C.D.; Shipers, L.R.

1992-01-01

Interagency panels evaluating nuclear thermal propulsion development options have consistently recognized the need for constructing a major new ground test facility to support fuel element and engine testing. This paper summarizes the requirements, configuration, and design issues of a proposed ground test complex for evaluating nuclear thermal propulsion engines and fuel elements being developed for the Space Nuclear Thermal Propulsion (SNTP) program. 2 refs

Method of manufacturing nuclear fuel elements

International Nuclear Information System (INIS)

Ishida, Masao; Oguma, Masaomi.

1980-01-01

Purpose: To effectively prevent the bending of nuclear fuel elements in the reactor by grinding the end faces of pellets due to their mutual sliding. Method: In the manufacturing process of nuclear fuel elements, a plurality of pellets whose sides have been polished are fed one by one by way of a feeding mechanism through the central aperture in an electric motor into movable arms and retained horizontally with the central axis by being held on the side. Then, the pellet held by one of the arms is urged to another pellet held by the other of the arms by way of a pressing mechanism and the mating end faces of both of the pellets are polished by mutual sliding. Thereafter, the grinding dusts resulted are eliminated by drawing pressurized air and then the pellets are enforced into a cladding tube. Thus, the pellets are charged into the cladding tube with both polished end faces being contacted to each other, whereby the axial force is uniformly transmitted within the end faces to prevent the bending of the cladding tube. (Kawakami, Y.)

Heavy-flavor production and medium properties in high-energy nuclear collisions. What next?

Energy Technology Data Exchange (ETDEWEB)

Aarts, G.; Allton, C. [Swansea University, Swansea (United Kingdom); Aichelin, J.; Gossiaux, P.B.; Nahrgang, M. [Universite de Nantes, SUBATECH, Ecole des Mines de Nantes, Nantes (France); Arnaldi, R.; Scomparin, E. [INFN, Sezione di Torino, Torino (Italy); Bass, S.A. [Duke University, Durham, NC (United States); Bedda, C.; Grelli, A.; Trzeciak, B.; Doremalen, L. van; Vermunt, L.; Vigolo, S. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); Brambilla, N. [Technische Universitaet Muenchen, Physik-Department and Excellence Cluster Universe, Garching (Germany); Technische Universitaet Muenchen, Institute for Advanced Study, Munich (Germany); Bratkovskaya, E. [GSI Helmholtzzentrum fuer Schwerionenforschung, Research Division and ExtreMe Matter Institute EMMI, Darmstadt (Germany); Frankfurt University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Braun-Munzinger, P. [GSI Helmholtzzentrum fuer Schwerionenforschung, Research Division and ExtreMe Matter Institute EMMI, Darmstadt (Germany); Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Bruno, G.E. [Dipartimento di Fisica and INFN, Bari (Italy); European Organization for Nuclear Research, Geneva (Switzerland); Dahms, T. [Technische Universitaet Muenchen, Physik-Department and Excellence Cluster Universe, Garching (Germany); Das, S.K. [University of Catania, Catania (Italy); Dembinski, H.; Schmelling, M. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Djordjevic, M. [University of Belgrade, Institute of Physics, Belgrade (Serbia); Ferreiro, E. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Frawley, A. [Florida State University, Tallahassee, FL (United States); Granier de Cassagnac, R.; Jo, M.; Nguyen, M. [Ecole Polytechnique, Laboratoire Leprince-Ringuet, Palaiseau (France); He, M. [Nanjing University of Science and Technology, Department of Applied Physics, Nanjing (China); Horowitz, W.A. [University of Cape Town, Department of Physics, Rondebosch (South Africa); Innocenti, G.M. [Massachusetts Institute of Technology, Cambridge, MA (United States); Kaczmarek, O. [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan (China); University of Bielefeld, Bielefeld (Germany); Kuijer, P.G. [National Institute for Subatomic Physics, Amsterdam (Netherlands); Laine, M. [University of Bern, AEC, Institute for Theoretical Physics, Bern (Switzerland); Lombardo, M.P. [INFN - Laboratori Nazionali di Frascati, Frascati (Italy); Mischke, A. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); National Institute for Subatomic Physics, Amsterdam (Netherlands); Munhoz, M.G.; Suaide, A.A.P. [Universidade de Sao Paulo (USP), Sao Paulo (Brazil); Oliveira da Silva, A.C.; Zanoli, H.J.C. [Utrecht University, Institute for Subatomic Physics, Utrecht (Netherlands); Universidade de Sao Paulo (USP), Sao Paulo (Brazil); Petreczky, P. [Brookhaven National Laboratory, Upton, NY (United States); Rothkopf, A. [Ruprecht-Karls-Universitaet Heidelberg, Institute for Theoretical Physics, Heidelberg (Germany); Song, T. [Frankfurt University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Stachel, J. [Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Tolos, L. [Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany); Institut de Ciencies de l' Espai (IEEC-CSIC), Bellaterra (Spain); Uras, A. [Domaine Scientifique de la Doua, Institute of Nuclear Physics, Villeurbanne Cedex (France); Xu, N. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Ye, Z. [University of Illinois, Chicago, IL (United States); Zhuang, P. [Tsinghua University, Beijng Shi (China)

2017-05-15

Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results from experiments and theoretical developments regarding open and hidden heavy-flavor dynamics have been debated at the Lorentz Workshop Tomography of the Quark-Gluon Plasma with Heavy Quarks, which was held in October 2016 in Leiden, The Netherlands. In this contribution, we summarize identified common understandings and developed strategies for the upcoming five years, which aim at achieving a profound knowledge of the dynamical properties of the quark-gluon plasma. (orig.)

Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

International Nuclear Information System (INIS)

Emrich, William J. Jr.

2008-01-01

To support a potential future development of a nuclear thermal rocket engine, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The test device simulates the environmental conditions (minus the radiation) to which nuclear rocket fuel components could be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner as to accurately reproduce the temperatures and heat fluxes normally expected to occur as a result of nuclear fission while at the same time being exposed to flowing hydrogen. This project is referred to as the Nuclear Thermal Rocket Element Environment Simulator or NTREES. The NTREES device is located at the Marshall Space flight Center in a laboratory which has been modified to accommodate the high powers required to heat the test articles to the required temperatures and to handle the gaseous hydrogen flow required for the tests. Other modifications to the laboratory include the installation of a nitrogen gas supply system and a cooling water supply system. During the design and construction of the facility, every effort was made to comply with all pertinent regulations to provide assurance that the facility could be operated in a safe and efficient manner. The NTREES system can currently supply up to 50 kW of inductive heating to the fuel test articles, although the facility has been sized to eventually allow test article heating levels of up to several megawatts

Getter for nuclear fuel elements

International Nuclear Information System (INIS)

Ross, W.T.; Williamson, H.E.

1976-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has disposed therein an improved getter capable of gettering reactive gases including a source of hydrogen. The getter comprises a composite with a substrate having thereon a coating capable of gettering reactive gases. The substrate has a greater coefficient of thermal expansion than does the coating, and over a period of time at reactor operating temperatures any protective film on the coating is fractured at various places and fresh portions of the coating are exposed to getter reactive gases. With further passage of time at reactor operating temperatures a fracture of the protective film on the coating will grow into a crack in the coating exposing further portions of the coating capable of gettering reactive gases

Mainz University, Institute of Nuclear Chemistry. Annual report 1993

International Nuclear Information System (INIS)

Denschlag, H.O.

1994-03-01

The report presents the results achieved by the Institute's five working groups in the following fields: Development of chemical separation processes, chemistry of ultraheavy elements; Developments in instrumentation; Nuclear fission and heavy ion reactions; Nuclear astrophysics, decay characteristics, structure of atoms and nuclei; Environmental pollution analysis. (orig./EF) [de

An introduction to nuclear astrophysics

International Nuclear Information System (INIS)

Norman, E.B.

1987-09-01

The role of nuclear reactions in astrophysics is described. Stellar energy generation and heavy element nucleosynthesis is explained in terms of specific sequences of charged-particle and neutron induced reactions. The evolution and final states of stars are examined. 20 refs. 11 figs., 2 tabs

Heavy ion physics

International Nuclear Information System (INIS)

Kalpakchieva, R.; Cherepanov, E.A.

1993-01-01

The international school-seminar on heavy ion physics had been organized in Dubna in may of 1993. The scientific program of reports covers the following main topics: synthesis and properties of heavy nuclei; synthesis and investigation of properties of exotic nuclei; experiments with radioactive nuclear beams; interaction between complex nuclei at low and intermediate energies. It also includes reports on laser spectroscopy and exotic nuclear beams, on some application of heavy ion beams for the problems of solid state physics, on construction of multidetector facilities and on developing of heavy ion accelerator complexes. Short communication

AMS of heavy elements with an ECR ion source and the ATLAS linear accelerator

CERN Document Server

Paul, M; Ahmad, I; Borasi, F; Caggiano, J; Davids, C N; Greene, J P; Harss, B; Heinz, A; Henderson, D J; Henning, W F; Jiang, C L; Pardo, R C; Rehm, K E; Rejoub, R; Seweryniak, D; Sonzogni, A; Uusitalo, J; Vondrasek, R C

2000-01-01

Detection of heavy elements by accelerator mass spectrometry with the electron cyclotron resonance ion source, Argonne linear accelerator and fragment mass analyzer (ECRIS-ATLAS-FMA) system has been developed. The use of the ECR-ATLAS system for AMS of heavy elements has two interesting features: (i) the efficient production of high-charge state ions in the ECR source ensures the elimination of molecular ions at the source stage, a highly attractive feature for any mass-spectrometric use not exploited so far; (ii) the linear acceleration based on velocity matching and the beam transport system act as a powerful mass filter for background suppression. We have shown that our system reaches an abundance sensitivity of 1x10 sup - sup 1 sup 4 for Pb isotopes. The sup 2 sup 3 sup 6 U detection sensitivity is sup 2 sup 3 sup 6 U/U > or approx. 1x10 sup - sup 1 sup 2 , limited mainly by the ion source output.

Nuclear reactor fuel elements

International Nuclear Information System (INIS)

Hindle, E. D.

1984-01-01

An array of rods is assembled to form a fuel element for a pressurized water reactor, the rods comprising zirconium alloy sheathed nuclear fuel pellets and containing helium. The helium gas pressure is selected for each rod so that it differs substantially from the helium gas pressure in its closest neighbors. In a preferred arrangement the rods are arranged in a square lattice and the helium gas pressure alternates between a relatively high value and a relatively low value so that each rod has as its closest neighbors up to four rods containing helium gas at the other pressure value

Nuclear reactor fuel elements

Energy Technology Data Exchange (ETDEWEB)

Hindle, E. D.

1984-10-16

An array of rods is assembled to form a fuel element for a pressurized water reactor, the rods comprising zirconium alloy sheathed nuclear fuel pellets and containing helium. The helium gas pressure is selected for each rod so that it differs substantially from the helium gas pressure in its closest neighbors. In a preferred arrangement the rods are arranged in a square lattice and the helium gas pressure alternates between a relatively high value and a relatively low value so that each rod has as its closest neighbors up to four rods containing helium gas at the other pressure value.

{gamma}-radiation of excited nuclear discrete levels in peripheral heavy ion collisions

Energy Technology Data Exchange (ETDEWEB)

Korotkikh, V.L.; Chikin, K.A. [Scobeltsyn Institute of Nuclear Physics, Moscow State University (Russian Federation)

2002-06-01

A new process of a nuclear excitation to discrete states in peripheral heavy ion collisions is studied. High-energy photons are emitted by the exited nuclei with energies up to a few tens of GeV at angles of a few hundred microradians with respect to the beam direction. We show that a two-stage process, where an electron-positron pair is produced by virtual photons emitted by nuclei and then the electron or positron excites the nucleus, has a large cross-section. It is equal to about 5 b for CaCa collisions. On the one hand, it produces a significant {gamma}-rays background in the nuclear fragmentation region but, on the other hand, it could be used for monitoring the nuclear beam intensity at the LHC. These secondary nuclear photons could be a good signal for triggering peripheral nuclear collisions. (orig.)

γ-radiation of excited nuclear discrete levels in peripheral heavy ion collisions

Science.gov (United States)

Korotkikh, V. L.; Chikin, K. A.

A new process of a nuclear excitation to discrete states in peripheral heavy ion collisions is studied. High-energy photons are emitted by the exited nuclei with energies up to a few tens of GeV at angles of a few hundred microradians with respect to the beam direction. We show that a two-stage process, where an electron-positron pair is produced by virtual photons emitted by nuclei and then the electron or positron excites the nucleus, has a large cross-section. It is equal to about 5 b for CaCa collisions. On the one hand, it produces a significant γ-rays background in the nuclear fragmentation region but, on the other hand, it could be used for monitoring the nuclear beam intensity at the LHC. These secondary nuclear photons could be a good signal for triggering peripheral nuclear collisions.

γ-radiation of excited nuclear discrete levels in peripheral heavy ion collisions

International Nuclear Information System (INIS)

Korotkikh, V.L.; Chikin, K.A.

2002-01-01

A new process of a nuclear excitation to discrete states in peripheral heavy ion collisions is studied. High-energy photons are emitted by the exited nuclei with energies up to a few tens of GeV at angles of a few hundred microradians with respect to the beam direction. We show that a two-stage process, where an electron-positron pair is produced by virtual photons emitted by nuclei and then the electron or positron excites the nucleus, has a large cross-section. It is equal to about 5 b for CaCa collisions. On the one hand, it produces a significant γ-rays background in the nuclear fragmentation region but, on the other hand, it could be used for monitoring the nuclear beam intensity at the LHC. These secondary nuclear photons could be a good signal for triggering peripheral nuclear collisions. (orig.)

Evolution of heavy-element abundances in the galactic halo and disk

International Nuclear Information System (INIS)

Mathews, G.J.; Cowan, J.J.; Schramm, D.N.

1988-05-01

The constraints on the universal energy density and cosmological constant from cosmochronological ages and the Hubble age are reviewed. Observational evidence for the galactic chemical evolution of the heavy-element chronometers is described in the context of numerical models. The viability of the recently discovered Th/Nd stellar chronometer is discussed, along with the suggestion that high r-process abundances in metal-poor stars may have resulted from a primordial r-process, as may be required by some inhomogeneous cosmologies

Initial Operation of the Nuclear Thermal Rocket Element Environmental Simulator

Science.gov (United States)

Emrich, William J., Jr.; Pearson, J. Boise; Schoenfeld, Michael P.

2015-01-01

The Nuclear Thermal Rocket Element Environmental Simulator (NTREES) facility is designed to perform realistic non-nuclear testing of nuclear thermal rocket (NTR) fuel elements and fuel materials. Although the NTREES facility cannot mimic the neutron and gamma environment of an operating NTR, it can simulate the thermal hydraulic environment within an NTR fuel element to provide critical information on material performance and compatibility. The NTREES facility has recently been upgraded such that the power capabilities of the facility have been increased significantly. At its present 1.2 MW power level, more prototypical fuel element temperatures nay now be reached. The new 1.2 MW induction heater consists of three physical units consisting of a transformer, rectifier, and inverter. This multiunit arrangement facilitated increasing the flexibility of the induction heater by more easily allowing variable frequency operation. Frequency ranges between 20 and 60 kHz can accommodated in the new induction heater allowing more representative power distributions to be generated within the test elements. The water cooling system was also upgraded to so as to be capable of removing 100% of the heat generated during testing In this new higher power configuration, NTREES will be capable of testing fuel elements and fuel materials at near-prototypic power densities. As checkout testing progressed and as higher power levels were achieved, several design deficiencies were discovered and fixed. Most of these design deficiencies were related to stray RF energy causing various components to encounter unexpected heating. Copper shielding around these components largely eliminated these problems. Other problems encountered involved unexpected movement in the coil due to electromagnetic forces and electrical arcing between the coil and a dummy test article. The coil movement and arcing which were encountered during the checkout testing effectively destroyed the induction coil in use at

From heavy nuclei to super-heavy nuclei

International Nuclear Information System (INIS)

Theisen, Ch.

2003-01-01

The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

Nuclear interactions in high energy heavy ions and applications in astrophysics

International Nuclear Information System (INIS)

Wefel, J.P.; Guzik, T.G.

1993-01-01

The overall objective is to study the mechanisms and the energy dependence of heavy ion fragmentation by studying the reactions of heavy ion projectiles (e.g. 4 He, 16 O, 20 Ne, 28 Si, 56 Fe) in a variety of targets (H, He, C, Si, Cu, Pb) and at a number of beam energies exceeding 0.1 GeV/nucleon. The results have application to questions in high-energy nuclear astrophysics. Most of the discussion is on low-energy 16 O, 28 Si data analysis. The description includes analysis procedures and techniques, detector calibrations, data selections and normalizations. Cross section results for the analysis are also presented. 83 figs., 6 tabs., 73 refs

Handling system for nuclear reactor fuel and reflector elements

International Nuclear Information System (INIS)

Hawke, B.C.; Goldman, L.A.

1980-01-01

A system for canning, inspecting and transferring to a storage area fuel and reflector elements from a nuclear reactor is described. The canning mechanism operates in a sealed gaseous environment and visual and mechanical inspection of the elements is possible by an operator from a remote shielded area. (UK)

Nuclear microscopy of biological specimens

International Nuclear Information System (INIS)

Watt, F.; Grime, G.W.; Brook, A.J.; Gadd, G.M.; Perry, C.C.; Pearce, R.B.; Turnau, K.; Watkinson, S.C.

1991-01-01

Recent developments in technology have enabled the scanning proton microprobe to scan at submicron spatial resolution on a routine basis. The use of the powerful combination of techniques PIXE (proton induced X-ray emission), nuclear (or Rutherford) backscattering (RBS), and secondary electron detection operating at this resolution will open up new areas in many scientific disciplines. This paper describes some of the work carried out in the biological sciences over the last year, using the Oxford SPM facility. Collaborations with biological scientists have drawn attention to the wealth of information that can be derived when these techniques are applied to micro-organisms, cells and plant tissue. Briefly described here are investigations into the uptake of heavy metals by the alga Pandorina morum, the structure of the diatom Stephanopyxis turris, the presence of various types of crystal structures within the cells of Spirogyra, the heavy metal uptake of a mycorrhizal fungus present in the bracken (Pteridium aquilinum) root, the role of sphagnum moss in the absorption of inorganic elements, the measurement of heavy metals in environmentally-adapted cells of the yeast Saccharomyces cerevisiae, and the elemental distribution in the growing tip of a spore from the plant Equisetum arvense, with special emphasis placed on the visual interpretation of the elemental and secondary-electron maps provided by the nuclear microscopical techniques. (orig.)

Chemistry of the heaviest elements

International Nuclear Information System (INIS)

Hoffman, D.C.

1996-01-01

Studies of the chemical properties of the elements at the uppermost end of the periodic table are discussed. Some historical perspective is given, but major emphasis is on recent studies. Isotopes of these elements are short-lived and, therefore, must be studied near the site of production. They must be produced with charged-particle beams at accelerators rather than via neutron capture. The use of radioactive heavy actinide targets is often required and the number of atoms produced is so small that any chemistry to be performed must be done on an ''atom-at-a-time'' basis. Furthermore, a knowledge of their nuclear properties is required in order to identify and detect them. To date, both gas and aqueous phase properties of elements as heavy as element 104 (rutherfordium) and element 105 (hahnium) have been investigated, even though their longest-lived known isotopes have half-lives of only 65 and 35 seconds, respectively. The experimental results show that their chemical properties cannot be simply extrapolated from the known properties of their lighter homologs in the periodic table, emphasizing the importance of obtaining additional experimental information for the heaviest elements to compare with predictions and help assess the influence of relativistic effects. The feasibility of the extension of chemical studies to still heavier elements is also discussed. (orig.)

Distribution of Heavy Metal Elements in the Sea Water, Algae and Fish ofMuria Peninsula Area

International Nuclear Information System (INIS)

Djati-Pramana, J; Agus-Taftazani; Sudarmadji

2000-01-01

Analysis of heavy metal elements in the specimens of sea water, brownalgae and kerapu fish from two area sampling Lemah Abang and Semat beach byINAA method was done. The same of such specimens from Krakal beach was takenfor control specimen. The aim of this investigation was to obtain a part ofinput data for EMSB program. Preparation after sampling was performed asfollows. Sea water sample was concentrated using 1/5 times of the initialvolume. Algae and fish specimens were crushed using N 2 liquid, dried at thefreeze dryer than were homogenized and screened through 100 mesh. The threeof those specimens were irradiated together for 12 hours in the Lazy Susanirradiation facility of Kartini reactor. Flux neutron was 5.85 . 10 10 n/cm 2 .sec. The heavy metal elements that could be identified were Sm, Se,Cr, Zr, Fe and Co. Concentration in the specimens from Muria peninsula wasrelatively higher comparated to control specimens. This might be use to thefound of these indicators to concentrated that of heavy metals from sea wateror their environment which has a higher concentration. From t test for 95 %probability to control specimens was showed that these was a significantdifference from all the detected elements. From the obtained data there was apollution indication in the area at the period of sampling. (author)

Key elements of a sustainable nuclear business case

Energy Technology Data Exchange (ETDEWEB)

Naidoo, D [Nuclear Consultants International - South Africa and AMEC Nuclear - United Kingdom, 20-35th Avenue, Umhlatuzana, Chatsworth, Durban (South Africa)

2008-07-01

The argument for nuclear power generation grows stronger internationally. Its increasing acceptance is attributable to scarcity of fossil fuel resources and environmental concerns. However, the potential implementation of nuclear power plants to solve our energy need has become an economic issue. The relatively high capital costs, the need to internalise all waste disposal and decommissioning costs are perceived barriers to the expansion of the nuclear industry. South Africa has embarked on an ambitious plan to provide 20 GW of electricity through the use of nuclear power by 2025. The success of the governments drive to stabilise electricity supply shall depend on the socio-economic conditions prevalent in the country over the stipulated period, but more specifically on the execution of a sustainable nuclear business model beyond the initial nuclear plant construction phases. This paper shall examine briefly, the key elements of a nuclear business case within the South African context. (authors)

Key elements of a sustainable nuclear business case

International Nuclear Information System (INIS)

Naidoo, D

2008-01-01

The argument for nuclear power generation grows stronger internationally. Its increasing acceptance is attributable to scarcity of fossil fuel resources and environmental concerns. However, the potential implementation of nuclear power plants to solve our energy need has become an economic issue. The relatively high capital costs, the need to internalise all waste disposal and decommissioning costs are perceived barriers to the expansion of the nuclear industry. South Africa has embarked on an ambitious plan to provide 20 GW of electricity through the use of nuclear power by 2025. The success of the governments drive to stabilise electricity supply shall depend on the socio-economic conditions prevalent in the country over the stipulated period, but more specifically on the execution of a sustainable nuclear business model beyond the initial nuclear plant construction phases. This paper shall examine briefly, the key elements of a nuclear business case within the South African context. (authors)

Nuclear quantum many-body dynamics: from collective vibrations to heavy-ion collisions

International Nuclear Information System (INIS)

Simenel, Cedric

2012-01-01

This report gives a summary of my research on nuclear dynamics during the past ten years. The choice of this field has been motivated by the desire to understand the physics of complex systems obeying quantum mechanics. In particular, the interplay between collective motion and single-particle degrees of freedom is a source of complex and fascinating behaviours. For instance, giant resonances are characterised by a collective vibration of many nucleons, but their decay may occur by the emission of a single nucleon. Another example could be taken from the collision of nuclei where the transfer of few nucleons may have a strong impact on the formation of a compound system is non trivial. To describe these complex systems, one needs to solve the quantum many-body problem. The description of the dynamics of composite systems can be very challenging, especially when two such systems interact. An important goal of nuclear physics is to find a unified way to describe the dynamics of nuclear systems. Ultimately, the same theoretical model should be able to describe vibrations, rotations, fission, all the possible outcomes of heavy-ion collisions (elastic and inelastic scattering, particle transfer, fusion, and multifragmentation), and even the dynamics of neutron star crust. This desire for a global approach to nuclear dynamics has strongly influenced my research activities. In particular, all the numerical applications presented in this report have been obtained from few numerical codes solving equations derived from the same variational principle. Beside the quest for a unified model of nuclear dynamics, possible applications of heavy-ion collisions such as the formation of new nuclei is also a strong motivation for the experimental and theoretical studies of reaction mechanisms. This report is not a review article, but should be considered as a reading guide of the main papers my collaborators and myself have published. It also gives the opportunity to detail some

Topical papers on heavy water, fuel fabrication and reactors

International Nuclear Information System (INIS)

1978-01-01

A total of four papers is presented. The first contribution of the Federal Republic of Germany reviews the market situation for reactors and the relations between reactor producers and buyers as reflected in sales agreements. The second West German contribution gives a world-wide survey of fuel element production as well as of fuel and fuel element demand up to the year 2000. The Canadian paper discusses the future prospects of heavy-water production, while the Ecuador contribution deals with small and medium-sized nuclear power plants

Jet production in heavy ion collisions

CERN Document Server

Calucci, G

2000-01-01

We discuss the production of jets in heavy ion collisions at LHC. The process allows one to determine to a good accuracy the value of the impact parameter of the nuclear collision in each single inelastic event. The knowledge of the geometry is a powerful tool for a detailed analysis of the process, making it possible to test the various different elements which, in accordance with present theoretical ideas, take part to the production mechanism. (8 refs).

Preliminary Nuclear Analysis for the HANARO Fuel Element with Burnable Absorber

Energy Technology Data Exchange (ETDEWEB)

Seo, Chul Gyo; Kim, So Young; In, Won Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

Burnable absorber is used for reducing reactivity swing and power peaking in high performance research reactors. Development of the HANARO fuel element with burnable absorber was started in the U-Mo fuel development program at HANARO, but detailed full core analysis was not performed because the current HANARO fuel management system is uncertain to analysis the HANARO core with burnable absorber. A sophisticated reactor physics system is required to analysis the core. The McCARD code was selected and the detailed McCARD core models, in which the basic HANARO core model was developed by one of the McCARD developers, are used in this study. The development of nuclear fuel requires a long time and correct developing direction especially by the nuclear analysis. This paper presents a preliminary nuclear analysis to promote the fuel development. Based on the developed fuel, the further nuclear analysis will improve reactor performance and safety. Basic nuclear analysis for the HANARO and the AHR were performed for getting the proper fuel elements with burnable absorber. Addition of 0.3 - 0.4% Cd to the fuel meat is promising for the current HANARO fuel element. Small addition of burnable absorber may not change any fuel characteristics of the HANARO fuel element, but various basic tests and irradiation tests at the HANARO core are required.

Heavy particle decay studies using different versions of nuclear potentials

Science.gov (United States)

Santhosh, K. P.; Sukumaran, Indu

2017-10-01

The heavy particle decay from 212-240Pa , 219-245Np , 228-246Pu , 230-249Am , and 232-252Cm leading to doubly magic 208Pb and its neighboring nuclei have been studied using fourteen versions of nuclear potentials. The study has shown that the barrier penetrability as well as the decay half-lives are found to vary with the nuclear potential used. The investigated decay events of the emission of the clusters 22Ne , 24Ne , 26Mg , 28Mg , 32Si and 33Si are not experimentally detected yet but may be detectable in the future. As most of the half-lives predicted are found to lie within the experimental upper limit, T 1/2 parents with varying slopes and intercepts. Also, it is to be noted that the linearity of the GN plots is unaltered using different nuclear potentials. The universal curve studied ( log10 T 1/2 vs. -ln P for various clusters emitted from various parents shows a linear behavior with the same slope and intercept irrespective of the nuclear potential used.

Measurements of Plutonium isotopes and the search for super-heavy elements via AMS

International Nuclear Information System (INIS)

Wallner, A.; Steier, P.; Golser, R.; Knie, K.; Kutschera, W.; Priller, A.; Hrnecek, E.; Jakopic, R.; Korschinek, G.

2006-01-01

Full text: Accelerator Mass Spectrometry (AMS) - being independent on the half-life of a radionuclide - provides a technique to determine isotope ratios with the highest sensitivity and allows the measurement of radionuclides over a wide dynamic range of concentration levels. A combination of AMS, Alpha Spectrometry and Liquid Scintillation Counting was used for the determination of the complete information on isotope ratios of Plutonium isotopes in different environmental reference samples (e.g. from the atolls of Mururoa and Fangataufa) and samples contaminated from nuclear reprocessing. Results for the isotopic ratios of the samples will be shown and the capabilities and detection limits achievable for determination of Pu will be discussed. The long-lived 244 Pu (t 1/2 = 80 Ma) and 247 Cm (t 1/2 = 15.6 Ma) have a very interesting application in astrophysics by detecting possible supernova-produced 244 Pu and 247 Cm in terrestrial archives. The expected extremely small concentrations of 244 Pu makes AMS the favorite method. The actual search for such long-lived extraterrestrial radionuclides and possible implications will be presented. The same method has also been explored for a pinprick-search of long-lived super-heavy elements in the mass region above Z=100. (author)

Nuclear physics workshop

International Nuclear Information System (INIS)

1988-01-01

This Workshop in Nuclear Physics related to the TANDAR, took place in Buenos Aires in April from 23 to 26, 1987, with attendance of foreign scientists. There were presented four seminars and a lot of studies which deal with the following fields: Nuclear Physics at medium energies, Nuclear Structure, Nuclear Reactions, Nuclear Matter, Instrumentation and Methodology for Nuclear Spectroscopy, Classical Physics, Quantum Mechanics and Field Theory. It must be emphasized that the Electrostatic Accelerator TANDAR allows to work with heavy ions of high energy, that opens a new field of work in PIXE (particle induced X-ray emission). This powerful analytic technique makes it possiblethe analysis of nearly all the elements of the periodic table with the same accuracy. (M.E.L.) [es

Quality assurance in nuclear fuel element component supply

International Nuclear Information System (INIS)

Jenkins, B.P.

1987-01-01

The paper describes the application of Quality Assurance to nuclear fuel element component supply. The Quality Assurance programme includes integrated procurement, purchasing, surveillance and receipt inspection functions. Purchasing policy is based on a consistent preference for competitive tendering. Multiple sourcing is used to encourage competitive pricing and increase security of supply. A receipt inspection facility is maintained to ensure the high product quality levels demanded by the nuclear industry. (U.K.)

Chemistry of the superheavy elements.

Science.gov (United States)

Schädel, Matthias

2015-03-13

The quest for superheavy elements (SHEs) is driven by the desire to find and explore one of the extreme limits of existence of matter. These elements exist solely due to their nuclear shell stabilization. All 15 presently 'known' SHEs (11 are officially 'discovered' and named) up to element 118 are short-lived and are man-made atom-at-a-time in heavy ion induced nuclear reactions. They are identical to the transactinide elements located in the seventh period of the periodic table beginning with rutherfordium (element 104), dubnium (element 105) and seaborgium (element 106) in groups 4, 5 and 6, respectively. Their chemical properties are often surprising and unexpected from simple extrapolations. After hassium (element 108), chemistry has now reached copernicium (element 112) and flerovium (element 114). For the later ones, the focus is on questions of their metallic or possibly noble gas-like character originating from interplay of most pronounced relativistic effects and electron-shell effects. SHEs provide unique opportunities to get insights into the influence of strong relativistic effects on the atomic electrons and to probe 'relativistically' influenced chemical properties and the architecture of the periodic table at its farthest reach. In addition, they establish a test bench to challenge the validity and predictive power of modern fully relativistic quantum chemical models. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Nuclear fission and reactions

International Nuclear Information System (INIS)

Anon.

1975-01-01

The nuclear fission research programs are designed to elucidate basic features of the fission process. Specifically, (1) factors determining how nucleons of a fissioning nucleus are distributed between two fission fragments, (2) factors determining kinetic energy and excitation energies of fragments, and (3) factors controlling fission lifetimes. To these ends, fission studies are reported for several heavy elements and include investigations of spontaneous and neutron-induced fission, heavy ion reactions, and high energy proton reactions. The status of theoretical research is also discussed. (U.S.)

Getter for nuclear fuel elements

International Nuclear Information System (INIS)

Ross, W.T.; Williamson, H.E.

1976-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed and has disposed therein an improved getter capable of gettering reactive gases including a source of hydrogen. The getter comprises a composite with a substrate having thereon a coating capable of gettering reactive gases. The substrate has a greater coefficient of thermal expansion than does the coating, and over a period of time at reactor operating temperatures any protective film on the coating is fractured at various places and fresh portions of the coating are exposed to getter reactive gases. With further passage of time at reactor operating temperatures a fracture of the protective film on the coating will grow into a crack in the coating exposing further portions of the coating capable of gettering reactive gases. 13 claims, 5 drawing figures

Hotspots for Vitamin-Steroid-Thyroid Hormone Response Elements Within Switch Regions of Immunoglobulin Heavy Chain Loci Predict a Direct Influence of Vitamins and Hormones on B Cell Class Switch Recombination.

Science.gov (United States)

Hurwitz, Julia L; Penkert, Rhiannon R; Xu, Beisi; Fan, Yiping; Partridge, Janet F; Maul, Robert W; Gearhart, Patricia J

2016-03-01

Vitamin A deficiencies are common throughout the world and have a significant negative influence on immune protection against viral infections. Mouse models demonstrate that the production of IgA, a first line of defense against viruses at mucosal sites, is inhibited in the context of vitamin A deficiency. In vitro, the addition of vitamin A to activated B cells can enhance IgA expression, but downregulate IgE. Previous reports have demonstrated that vitamin A modifies cytokine patterns, and in so doing may influence antibody isotype expression by an indirect mechanism. However, we have now discovered hundreds of potential response elements among Sμ, Sɛ, and Sα switch sites within immunoglobulin heavy chain loci. These hotspots appear in both mouse and human loci and include targets for vitamin receptors and related proteins (e.g., estrogen receptors) in the nuclear receptor superfamily. Full response elements with direct repeats are relatively infrequent or absent in Sγ regions although half-sites are present. Based on these results, we pose a hypothesis that nuclear receptors have a direct effect on the immunoglobulin heavy chain class switch recombination event. We propose that vitamin A may alter S site accessibility to activation-induced deaminase and nonhomologous end-joining machinery, thereby influencing the isotype switch, antibody production, and protection against viral infections at mucosal sites.

Nuclear generating station and heavy water plant cost estimates for strategy studies

International Nuclear Information System (INIS)

Archinoff, G.H.

1979-07-01

Nuclear generating station capital, operating and maintenance costs are basic input data for strategy analyses of alternate nuclear fuel cycles. This report presents estimates of these costs for natural uranium CANDU stations, CANDU stations operating on advanced fuel cycles, and liquid metal fast breeder reactors. Cost estimates for heavy water plants are also presented. The results show that station capital costs for advanced fuel cycles are not expected to be significantly greater than those for natural uranium stations. LMFBR capital costs are expected to be 25-30 percent greater than for CANDU's. (auth)

Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals

International Nuclear Information System (INIS)

2013-01-01

The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

Direct harvesting of Helium-3 (3He) from heavy water nuclear reactors

International Nuclear Information System (INIS)

Bentoumi, G.; Didsbury, R.; Jonkmans, G.; Rodrigo, L.; Sur, B.

2013-01-01

The thermal neutron activation of deuterium inside a heavy-water-moderated or -cooled nuclear reactor produces a build-up of tritium in the heavy water. The in situ decay of tritium can, for certain reactor types and operating conditions, produce potentially useable amounts of 3 He, which can be directly extracted via the heavy-water cover gas without first separating, collecting and storing tritium outside the reactor. It is estimated that the amount of 3 He available for recovery from the moderator cover gas of a 700 MWe class Pressurized Heavy Water Reactor (PHWR) ranges from 0.1 to 0.7 m 3 (STP) per annum, varying with the tritium activity buildup in the moderator. The harvesting of 3 He would generate approximately 12.7 m 3 (STP) of 3 He, worth more than $30M at current market rates, over a typical 25-year operating cycle of the PHWR. This paper discusses the production of 3 He in the moderator of a PHWR and its extraction from the 4 He moderator cover gas system using conventional methods. (author)

Application of finite element numerical technique to nuclear reactor geometries

Energy Technology Data Exchange (ETDEWEB)

Rouai, N M [Nuclear engineering department faculty of engineering Al-fateh universty, Tripoli (Libyan Arab Jamahiriya)

1995-10-01

Determination of the temperature distribution in nuclear elements is of utmost importance to ensure that the temperature stays within safe limits during reactor operation. This paper discusses the use of Finite element numerical technique (FE) for the solution of the two dimensional heat conduction equation in geometries related to nuclear reactor cores. The FE solution stats with variational calculus which considers transforming the heat conduction equation into an integral equation I(O) and seeks a function that minimizes this integral and hence gives the solution to the heat conduction equation. In this paper FE theory as applied to heat conduction is briefly outlined and a 2-D program is used to apply the theory to simple shapes and to two gas cooled reactor fuel elements. Good results are obtained for both cases with reasonable number of elements. 7 figs.

Application of finite element numerical technique to nuclear reactor geometries

International Nuclear Information System (INIS)

Rouai, N. M.

1995-01-01

Determination of the temperature distribution in nuclear elements is of utmost importance to ensure that the temperature stays within safe limits during reactor operation. This paper discusses the use of Finite element numerical technique (FE) for the solution of the two dimensional heat conduction equation in geometries related to nuclear reactor cores. The FE solution stats with variational calculus which considers transforming the heat conduction equation into an integral equation I(O) and seeks a function that minimizes this integral and hence gives the solution to the heat conduction equation. In this paper FE theory as applied to heat conduction is briefly outlined and a 2-D program is used to apply the theory to simple shapes and to two gas cooled reactor fuel elements. Good results are obtained for both cases with reasonable number of elements. 7 figs

A Taxonomy for Heavy-Duty Telemanipulation Tasks Using Elemental Actions

Directory of Open Access Journals (Sweden)

Alexander Owen-Hill

2013-10-01

Full Text Available In the maintenance of large scientific facilities, telemanipulation procedures can involve various subprocedures which in turn are made up of a sequence of subtasks. This work presents a taxonomy which describes a set of elemental actions for heavy-duty telemanipulation, along with an example of these actions in a standard maintenance subprocedure. As maintenance tasks are often very different at high-level, this generalized way of deconstructing tasks allows a highly adaptable approach to describe the sequence of any procedure, which can then be used for such applications as task monitoring, automation or detection of incomplete tasks. We describe in detail the properties of each elemental action and apply the taxonomy to an example subprocedure to show how the process can be generalizable. An automatic state-machine creation stage is shown, which would be used at the task scheduling stage to simplify calculations carried out during the moment-by-moment execution of the task.

Future Perspectives for the Application of Low Temperature Detectors in Heavy Ion Physics

International Nuclear Information System (INIS)

Egelhof, P.; Kraft-Bermuth, S.

2009-01-01

Calorimetric low temperature detectors have the potential to become powerful tools for applications in many fields of heavy ion physics. A brief overview of heavy ion physics is given, and the next generation heavy ion facility FAIR is described with a special emphasis on the potential advantage of Low Temperature Detectors (LTDs) for applications in heavy ion physics. For prototype LTDs for the energy sensitive detection of heavy ions excellent results with respect to energy resolution down to δE/E = 1-2x10 -3 for a wide range of incident energies, and with respect to other detector properties, such as energy linearity with no indication of pulse height defects even for the heaviest ions, have been obtained. In addition, prototype detectors for hard X-rays have shown energy resolutions down to δE = 30-40eV at 60 keV. Consequently, both detector schemes have already been successfully used for first experiments. At present, the design and setup of large solid angle detector arrays is in progress. With the already achieved performance, LTDs promise a large potential for applications in atomic and nuclear heavy ion physics. A brief overview of prominent examples, including high-resolution nuclear spectroscopy, nuclear structure studies with radioactive beams, superheavy element research, as well as high-resolution atomic spectroscopy on highly charged ions and tests of QED in strong electromagnetic fields is presented.

Multidimensional elemental analysis with the Sandia nuclear microprobe

International Nuclear Information System (INIS)

Doyle, B.L.

1988-01-01

It is well known that many of the ion beam analysis techniques such as Rutherford backscattering spectrometry, elastic recoil detection, resonant and nonresonant nuclear reaction analysis can be used to nondestructively obtain concentration depth profiles of elements in solids. When these techniques are combined with the small beam spot capabilities of a scanned nuclear microprobe, sample composition can be determined in up to three dimensions. This paper will review the various procedures used to collect and analyze multidimensional data using the Sandia nuclear microprobe. In addition, examples of how these data are being used in the study of materials will be shown. (author)

Atomic data for heavy element impurities in fusion reactors. Summary report of first IAEA research co-ordination meeting

International Nuclear Information System (INIS)

Clark, R.E.H.

2006-01-01

Twelve international experts discussed in detail the properties of heavy elements relevant to fusion energy research participated at the first Research Coordination Meeting (RCM) of the Coordinated Research Project (CRP) on 'Atomic data for heavy element impurities in fusion reactors' at IAEA Headquarters on 14-15 November 2005. The participants summarized all recent relevant developments in their research efforts. Detailed discussions took place to formulate specific objectives for the CRP. From a list of data needs and a review of current research capabilities, a detailed work plan was formulated for the first phase of the CRP. The discussions, conclusions and recommendations of the RCM are briefly described in this report. (author)

Dynamic SPR monitoring of yeast nuclear protein binding to a cis-regulatory element

International Nuclear Information System (INIS)

Mao, Grace; Brody, James P.

2007-01-01

Gene expression is controlled by protein complexes binding to short specific sequences of DNA, called cis-regulatory elements. Expression of most eukaryotic genes is controlled by dozens of these elements. Comprehensive identification and monitoring of these elements is a major goal of genomics. In pursuit of this goal, we are developing a surface plasmon resonance (SPR) based assay to identify and monitor cis-regulatory elements. To test whether we could reliably monitor protein binding to a regulatory element, we immobilized a 16 bp region of Saccharomyces cerevisiae chromosome 5 onto a gold surface. This 16 bp region of DNA is known to bind several proteins and thought to control expression of the gene RNR1, which varies through the cell cycle. We synchronized yeast cell cultures, and then sampled these cultures at a regular interval. These samples were processed to purify nuclear lysate, which was then exposed to the sensor. We found that nuclear protein binds this particular element of DNA at a significantly higher rate (as compared to unsynchronized cells) during G1 phase. Other time points show levels of DNA-nuclear protein binding similar to the unsynchronized control. We also measured the apparent association complex of the binding to be 0.014 s -1 . We conclude that (1) SPR-based assays can monitor DNA-nuclear protein binding and that (2) for this particular cis-regulatory element, maximum DNA-nuclear protein binding occurs during G1 phase

Nuclear structure notes on element 115 decay chains

International Nuclear Information System (INIS)

Rudolph, D.; Sarmiento, L. G.; Forsberg, U.

2015-01-01

Hitherto collected data on more than hundred α-decay chains stemming from element 115 are combined to probe some aspects of the underlying nuclear structure of the heaviest atomic nuclei yet created in the laboratory

Nuclear structure notes on element 115 decay chains

Energy Technology Data Exchange (ETDEWEB)

Rudolph, D., E-mail: Dirk.Rudolph@nuclear.lu.se; Sarmiento, L. G.; Forsberg, U. [Department of Physics, Lund University, 22100 Lund (Sweden)

2015-10-15

Hitherto collected data on more than hundred α-decay chains stemming from element 115 are combined to probe some aspects of the underlying nuclear structure of the heaviest atomic nuclei yet created in the laboratory.

Detection of heavy-water leaks in nuclear reactors : a novel method

International Nuclear Information System (INIS)

Murthy, M.S.; Gor, M.K.

2002-01-01

Technical Physics and Prototype Engineering Division, BARC has designed, developed and produced several high sensitivity mass spectrometer helium leak detectors over a period of two decades. Sometimes back, when there was a problem of detecting heavy water leaks in situ in one of the nuclear power reactors of the Department of Atomic Energy, it was referred to this division for a technical solution. After discussing with the site engineers, the various problems involved in the on-line detection of heavy water leaks especially near the end fittings of the coolant assemblies, a novel method of leak detection was developed. Some of the salient features of the method and the results obtained in the laboratory tests are given in this paper. (author)

Chemical elimination of alumina in suspension in nuclear reactors heavy water

International Nuclear Information System (INIS)

Ledoux, A.

1967-02-01

Corrosion of aluminium in contact with moderating water in nuclear reactor leads to the formation of an alumina hydrosol which can have an adverse effect on the operation of the reactor. Several physical methods have been used in an attempt to counteract this effect. The method proposed here consists in the elimination of the aluminium by dissolution and subsequent fixation in the ionic form on mixed-bed ion-exchange resin. In order to do this, the parameters and the values of these parameters most favorable to the dissolution process have been determined. If the moderator is heavy water, the deuterated acid can be prepared by converting a solution in heavy water to a salt of the acid using a deuterated cationic resin. (author) [fr

Heavy flavours in ultra-relativistic heavy ions collisions

International Nuclear Information System (INIS)

Rosnet, Ph.

2008-01-01

The ultra-relativistic collisions of heavy ions are the today's only means to tackle in laboratory conditions the phase diagram in quantum chromodynamics and the strong interaction. The most recent theoretical studies predict a phase transition between the cold nuclear matter (a hadronic gas) and a plasma of quarks and gluons. Heavy flavour can characterize the nuclear matter produced in a heavy ion collision as well as its spatial-temporal evolution. Their study can be made through their decay into muons. The first part of this work presents the issue of ultra-relativistic heavy ion collisions and the role of heavy flavours. In the second part the author reviews the results of experiments performed at RHIC and particularly presents the analysis of the mass spectrum of dimuons in the Phenix experiment. The third part describes the muon trigger system of the Alice experiment at CERN and the expected performances for the study of di-muons

The origin of nuclear spin and its effect durning intermediate energy heavy ion collisions

International Nuclear Information System (INIS)

Zhang Guoqiang; Cao Xiguang; Fu Yao; Ma Yugang; Cai Xiangzhou; Wang Hongwei; Fang Deqing; Tian Wendong; Chen Jingen; Guo Wei; Liu Guihua

2010-01-01

We use the heavy-ion phase-space exploration (HIPSE) model to discuss the origin of the nuclear spin and its effect in Intermediate energy nuclear reaction. It is found that the spin of projectile depends on the impact parameter of the reaction system heavily, while on the violence lightly by contrast. Some interesting multifragmentation phenomena related to the spin are shown, especially those of phase transition. At the same time, the role of excited energy for multifragmentation is also invested. We find the later plays a more robust role durning the nuclear disintegration. (authors)

Accelerator mass spectrometry of heavy elements: /sup 36/Cl to /sup 205/Pb

Energy Technology Data Exchange (ETDEWEB)

Henning, W

1987-08-25

Measurements are discussed in which the technique of accelerator mass spectrometry was applied to problems involving heavy radioisotopes. These measurements, which depend on the ion energies that can be reached with the new heavy-ion accelerator facilities, were performed at the Argonne tandem linac accelerator system (ATLAS) and at the UNILAC accelerator at GSI. The topics include a discussion of measurements of long nuclear lifetimes, of radioisotope detection of interest to solar neutrino experiments, and of a determination of the /sup 41/Ca concentration in natural samples of terrestrial origin by making use of isotopic pre-enrichment in an isotope separator. A long-known method of isobar separation, employing a gas-filled magnetic field region, has been revived for some of these measurements and its characteristics and advantages are briefly reviewed.

Status of the low-energy super-heavy element facility at RIKEN

Energy Technology Data Exchange (ETDEWEB)

Schury, P., E-mail: schury@riken.jp [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wada, M.; Ito, Y. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Arai, F. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Kaji, D. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Kimura, S. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Morimoto, K.; Haba, H. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Jeong, S. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Koura, H. [Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Miyatake, H. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Morita, K.; Reponen, M. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ozawa, A. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Sonoda, T.; Takamine, A. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wollnik, H. [Dept. Chemistry and BioChemistry, New Mexico State University, Las Cruces, NM (United States)

2016-06-01

In order to investigate nuclei produced via fusion–evaporation reactions, especially super-heavy elements (SHE), we have begun construction of a facility for conversion of fusion–evaporation residues (EVR) to low-energy beams. At the base of this facility is a small cryogenic gas cell utilizing a traveling wave RF-carpet, located directly following the gas-filled recoil ion separator GARIS-II, which will thermalize EVRs to convert them into ion beams amenable to ion trapping. We present here the results of initial studies of this small gas cell.

Investigation on laser welding characteristics for appendage of bearing pads of nuclear fuel element

International Nuclear Information System (INIS)

Kim, S. S.; Kim, W. K.; Park, C. H.; Ko, J. H.; Lee, J. W.; Yang, M. S.

2001-01-01

In CANDU nuclear fuel manufacturing the brazing technology has been adopted conventionally to attach the bearing pads of nuclear fuel elements. However, in order to meet good performance of nuclear fuel and improved working efficiency, we started developing the laser welding technology for attachments of the bearing pads. Since the YAG laser can be suitable for small parts and transmit the beam through the optical fiber, the process is corresponding to mass-production with working shops. Making the most of this feature, we have developed the laser welding for appendage of the bearing pads of nuclear fuel elements, and has studied on the laser welding characterisitcs of appendages for nuclear fuel element

Heavy-flavor production and medium properties in high-energy nuclear collisions --What next?

NARCIS (Netherlands)

Aarts, G.; Aichelin, J.; Allton, C.; Arnaldi, R.; Bass, S. A.; Bedda, C.; Brambilla, N.; Bratkovskaya, E.; Braun-Munzinger, P.; Bruno, G. E.; Dahms, T.; Das, S. K.; Dembinski, H.; Djordjevic, M.; Ferreiro, E. G.; Frawley, A.; Gossiaux, P. B.; Granier de Cassagnac, R.; Grelli, A.; He, Ming; Horowitz, W. A.; Innocenti, G. M.; Jo, M.; Kaczmarek, O.; Kuijer, P; Laine, M.; Lombardo, M. P.; Mischke, A.; Munhoz, M. G.; Nahrgang, M.; Nguyen, Mai; Oliveira da Silva, A. C.; Petreczky, P.; Rothkopf, A.; Schmelling, M.; Scomparin, E.; Song, Ting; Stachel, J.; Suaide, A. A P; Tolos, L.; Trzeciak, B.; Uras, A.; van Doremalen, L.; Vermunt, L.; Vigolo, S.; Xu, N.; Ye, Z.; Zanoli, H.J.C.; Zhuang, P.

2017-01-01

Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results

Fluid pressure method for recovering fuel pellets from nuclear fuel elements

International Nuclear Information System (INIS)

John, C.D. Jr.

1979-01-01

A method is described for removing fuel pellets from a nuclear fuel element without damaging the fuel pellets or fuel element sheath so that both may be reused. The method comprises holding the fuel element while a high pressure stream internally pressurizes the fuel element to expand the fuel element sheath away from the fuel pellets therein so that the fuel pellets may be easily removed

The nuclear equation of state in effective relativistic field theories and pion yields in heavy-ion collisions

International Nuclear Information System (INIS)

Schoenhofen, M.; Cubero, M.; Gering, M.; Sambataro, M.; Feldmeier, H.; Noerenberg, W.

1989-06-01

Within the framework of relativistic field theory for nucleons, deltas, scalar and vector mesons, a systematic study of the nuclear equation of state and its relation to pion yields in heavy-ion collisions is presented. Not the compressibility but the effective nucleon mass at normal nuclear density turns out to be the most sensitive parameter. Effects from vaccum fluctuations are well modelled within the mean-field no-sea approximation by self-interaction terms for the scalar meson field. Incomplete thermalization in the fireball may be the reason for the low pion yields observed in heavy-ion collisions. (orig.)

Relative radiative decay rates of vacancies in L-subshells of heavy elements

International Nuclear Information System (INIS)

Barros Leite, C.V. de; Pinho, A.G. de; Castro Faria, N.V. de.

1977-01-01

Relative radiative decay of vacancies in L-subshells were measured for a large number of heavy elements with a Si(Li) detection system. A graphical method was employed to analyze the x-ray spectra so obtained. Systematic results are presented together with other already published results obtained in our laboratories in recent years. This covers the interval 74<=Z<=93. Results are compared with theoretical predictions and experimental data from other authors and some general features are noted

Determination of trace elements and heavy metals in sediment using x-ray fluorescence

International Nuclear Information System (INIS)

Sidahmed, Muataz Ahmed Ibrahem

2014-01-01

In this study, 30 sediment samples were taken randomly from the area of Suba south of Khartoum state. Trace elements and heavy metal were determined in sediments samples using x-ray fluoresce spectroscopy (X RF). K, Ca, Ti, Mn, Fe, Cu, Zn, Pb, Rb, Sr, and Zr were determined by X RF. Standard Reference Material (SRM) from international Atomic Energy Agency (IAEA-Soil-7) has been used to achieve accuracy of X RF method. Measured values were found in agreements with certified values. The average elemental concentrations of K, Ca, Ti, Mn, Fe, Cu, Zn, Pb, Rb, Sr, and Zr were 5882.7, 20703.3, 6264.3, 460.97, 26713.3, 7.7, 43.4, 18.6, 28.6, 144.8, and 173.06, respectively. Correlation between elements was performed also cluster analysis was used to check the similarly between the samples result. The result of study were compared with previous studies and the concentrations of some elements found to be similar.(Author)

HAT-P-26b: A Neptune-mass exoplanet with a well-constrained heavy element abundance.

Science.gov (United States)

Wakeford, Hannah R; Sing, David K; Kataria, Tiffany; Deming, Drake; Nikolov, Nikolay; Lopez, Eric D; Tremblin, Pascal; Amundsen, David S; Lewis, Nikole K; Mandell, Avi M; Fortney, Jonathan J; Knutson, Heather; Benneke, Björn; Evans, Thomas M

2017-05-12

A correlation between giant-planet mass and atmospheric heavy elemental abundance was first noted in the past century from observations of planets in our own Solar System and has served as a cornerstone of planet-formation theory. Using data from the Hubble and Spitzer Space Telescopes from 0.5 to 5 micrometers, we conducted a detailed atmospheric study of the transiting Neptune-mass exoplanet HAT-P-26b. We detected prominent H 2 O absorption bands with a maximum base-to-peak amplitude of 525 parts per million in the transmission spectrum. Using the water abundance as a proxy for metallicity, we measured HAT-P-26b's atmospheric heavy element content ([Formula: see text] times solar). This likely indicates that HAT-P-26b's atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime, with little contamination from metal-rich planetesimals. Copyright © 2017, American Association for the Advancement of Science.

Nuclear microprobe studies of elemental distribution in the seagrass Thalassodendron ciliatum

Energy Technology Data Exchange (ETDEWEB)

Barnabas, A.D. E-mail: alban@pixie.udw.ac.za; Przybylowicz, W.J.; Mesjasz-Przybylowicz, J.; Pineda, C.A

1999-09-02

Elemental levels and distributions in various organs (leaves, upright stems, rhizomes and roots) of the seagrass Thalassodendron ciliatum were determined using the NAC nuclear microprobe. Elemental distributions were obtained using the true elemental imaging system Dynamic Analysis (DA). Cl was the most abundant element present in the organs, occurring in all tissues, but present in relatively low concentrations in epidermal cells of leaves and roots. Na, K, S and Mg were also abundant and occurred in all organ tissues. Ca concentration was highest in the leaves, especially in the epidermis. Low concentrations of P were found and its tissue distribution was limited. Although Fe, Cu, Zn, Mn, Br, Ti and Si were present in relatively small amounts, enrichment of the epidermis with Fe, Ti and Si in all organs, was observed. Fe concentration was the highest in rhizomes while Si concentration was highest in upright stems. The significance of these elemental distribution patterns and the value of the nuclear microprobe in elemental analysis of seagrasses are discussed.

The discovery of elements 107 to 112

Directory of Open Access Journals (Sweden)

Hofmann Sigurd

2016-01-01

Full Text Available In the 1960s, theoretical concepts prepared the path to nuclear matter with proton and neutron numbers far beyond the nuclei known at that time. The new laboratory GSI was founded for research on reactions with heavy ions, in particular those for production of the predicted super-heavy nuclei. In this contribution it is presented how the interaction between experiment and theory resulted in a continuous improvement of the experimental set-ups on the one hand, and of the knowledge of the processes during the nuclear reaction and of the properties of the produced nuclei on the other hand. In the course of this work six new elements from 107 to 112 were produced and identified. An overview of the present status of experimental results and a comparison with theoretical interpretations is given.

Report of the joint seminar on heavy-ion nuclear physics and nuclear chemistry in the energy region of tandem accelerators (II)

International Nuclear Information System (INIS)

1986-04-01

A meeting of the second joint seminar on Heavy-Ion Nuclear Physics and Nuclear Chemistry in the Energy Region of Tandem Accelerators was held after an interval of two years at the Tokai Research Establishment of the JAERI, for three days from January 9 to 11, 1986. In the seminar, about 70 nuclear physicists and nuclear chemists of JAERI and other Institutes participated, and 38 papers were presented. These include general reviews and topical subjects which have been developed intensively in recent years, as well as the new results obtained by using the JAERI tandem accelerator. This report is a collection of the papers presented to the seminar. (author)

Commissioning a Rotating Target Wheel Assembly for Heavy Element Studies

Science.gov (United States)

Fields, L. D.; Bennett, M. E.; Mayorov, D. A.; Folden, C. M.

2013-10-01

The heaviest elements are produced artificially by fusing nuclei of light elements within an accelerator to form heavier nuclei. The most direct method to increase the production rate of nuclei is to increase the beam intensity, necessitating the use of a rotating target to minimize damage to the target by deposited heat. Such a target wheel was constructed for heavy element research at Texas A&M University, Cyclotron Institute, consisting of a wheel with three banana-shaped target cutouts. The target is designed to rotate at 1700 rpm, and a fiber optic cable provides a signal to trigger beam pulsing in order to avoid irradiating the spokes between target segments. Following minor mechanical modifications and construction of a dedicated electrical panel, the rotating target assembly was commissioned for a beam experiment. A 15 MeV/u beam of 20Ne was delivered from the K500 cyclotron and detected by a ruggedized silicon detector. The beam pulsing response time was characterized as a function of the rational frequency of the target wheel. Preliminary analysis suggests that the K500 is capable of pulsing at rates of up to 250 Hz, which is sufficient for planned future experiments. Funded by DOE and NSF-REU Program.

End plug welding of nuclear fuel elements-AFFF experience

International Nuclear Information System (INIS)

Bhatt, R.B.; Singh, S.; Aniruddha Kumar; Amit; Arun Kumar; Panakkal, J.P.; Kamath, H.S.

2004-01-01

Advanced Fuel Fabrication Facility is engaged in the fabrication of mixed oxide (U,Pu)O 2 fuel elements of various types of nuclear reactors. Fabrication of fuel elements involves pellet fabrication, stack making, stack loading and end plug welding. The requirement of helium bonding gas inside the fuel elements necessitates the top end plug welding to be carried out with helium as the shielding gas. The severity of the service conditions inside a nuclear reactor imposes strict quality control criteria, which demands for almost defect free welds. The top end plug welding being the last process step in fuel element fabrication, any rejection at this stage would lead to loss of effort prior to this step. Moreover, the job becomes all the more difficult with mixed oxide (MOX) as the entire fabrication work has to be carried out in glove box trains. In the case of weld rejection, accepted pellets are salvaged by cutting the clad tube. This is a difficult task and recovery of pellets is low (requiring scrap recovery operation) and also leads to active metallic waste generation. This paper discusses the experience gained at AFFF, in the past 12 years in the area of end plug welding for different types of MOX fuel elements

State of the Art Report for Development of Control Element Drive Mechanism of the APR+ Reactor

International Nuclear Information System (INIS)

Lee, Jae Seon; Choi, Suhn; Song, Chul Hwa

2008-10-01

Recently newly-developed nuclear reactors with increased safety and enhanced performance by developed countries in the nuclear area are competing in the global nuclear market. Several reactors, for example AP600 and AP1000 by Westinghouse Electric Co. in USA, EPR by Areva in Europe, APWR by Mitsubishi Heavy Industry in Japan in the pressurized power reactor, are competing to preoccupy the nuclear market during Nuclear Renaissance. Dedicated control element drive mechanism with enhanced performance and increased safety are developed for these new reactors. And load follow capability is required, and it is estimated that load follow requirement make design requirement of a control element drive mechanism harsh. It is necessary to review the current technical state of a control element drive mechanism. This work is aimed to review the design characteristics of a past and current control element drive mechanism for a nuclear reactor and to check the direction and goal of CEDM design development recently

State of the Art Report for Development of Control Element Drive Mechanism of the APR+ Reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae Seon; Choi, Suhn; Song, Chul Hwa

2008-10-15

Recently newly-developed nuclear reactors with increased safety and enhanced performance by developed countries in the nuclear area are competing in the global nuclear market. Several reactors, for example AP600 and AP1000 by Westinghouse Electric Co. in USA, EPR by Areva in Europe, APWR by Mitsubishi Heavy Industry in Japan in the pressurized power reactor, are competing to preoccupy the nuclear market during Nuclear Renaissance. Dedicated control element drive mechanism with enhanced performance and increased safety are developed for these new reactors. And load follow capability is required, and it is estimated that load follow requirement make design requirement of a control element drive mechanism harsh. It is necessary to review the current technical state of a control element drive mechanism. This work is aimed to review the design characteristics of a past and current control element drive mechanism for a nuclear reactor and to check the direction and goal of CEDM design development recently.

Progress Report. Institute of Atomic Physics, Institute of Physics and Nuclear Engineering, Department of Heavy Ion Physics. 1992-1993

International Nuclear Information System (INIS)

Grama, C.; Ionescu-Bujor, M.; Poenaru, D.; Pop, A.

1994-01-01

A brief account of the research and development activities carried out in the Department of Heavy Ion Physics, Institute of Atomic Physics, Institute of Physics and Nuclear Engineering, Bucharest, during the period January 1992 to December 1993 is presented. The main topics concern nuclear structure models and methods, heavy-ion-induced reactions, and general properties of nuclei and nuclear energy levels. Also, works dealing with particle detection, measuring instruments and methods are reported. The report contains two sections. The first covers the research in progress in the fields of nuclear structure, nuclear reactions, atomic physics, accelerator, instrumentation, methods and computer codes. The second one, the appendix, contains the list of publications of the Department staff in journals and proceedings, books, and preprints, the conference contributions, the academic degrees awarded, the scientific exchanges, and the list of scientific personnel

Classical-limit S-matrix for heavy ion scattering

International Nuclear Information System (INIS)

Donangelo, R.J.

1977-01-01

An integral representation for the classical limit of the quantum mechanical S-matrix is developed and applied to heavy-ion Coulomb excitation and Coulomb-nuclear interference. The method combines the quantum principle of superposition with exact classical dynamics to describe the projectile-target system. A detailed consideration of the classical trajectories and of the dimensionless parameters that characterize the system is carried out. The results are compared, where possible, to exact quantum mechanical calculations and to conventional semiclassical calculations. It is found that in the case of backscattering the classical limit S-matrix method is able to almost exactly reproduce the quantum-mechanical S-matrix elements, and therefore the transition probabilities, even for projectiles as light as protons. The results also suggest that this approach should be a better approximation for heavy-ion multiple Coulomb excitation than earlier semiclassical methods, due to a more accurate description of the classical orbits in the electromagnetic field of the target nucleus. Calculations using this method indicate that the rotational excitation probabilities in the Coulomb-nuclear interference region should be very sensitive to the details of the potential at the surface of the nucleus, suggesting that heavy-ion rotational excitation could constitute a sensitive probe of the nuclear potential in this region. The application to other problems as well as the present limits of applicability of the formalism are also discussed

Method for inspecting nuclear reactor fuel elements

International Nuclear Information System (INIS)

Jabsen, F.S.

1979-01-01

A technique for disassembling a nuclear reactor fuel element without destroying the individual fuel pins and other structural components from which the element is assembled is described. A traveling bridge and trolley span a water-filled spent fuel storage pool and support a strongback. The strongback is under water and provides a working surface on which the spent fuel element is placed for inspection and for the manipulation that is associated with disassembly and assembly. To remove, in a non-destructive manner, the grids that hold the fuel pins in the proper relative positions within the element, bars are inserted through apertures in the grids with the aid of special tools. These bars are rotated to flex the adjacent grid walls and, in this way relax the physical engagement between protruding portions of the grid walls and the associated fuel pins. With the grid structure so flexed to relax the physical grip on the individual fuel pins, these pins can be withdrawn for inspection or replacement as necessary without imposing a need to destroy fuel element components

Determination of trace element and heavy metal in black tea and tea leaves using x-ray fluorescence

International Nuclear Information System (INIS)

Salih, Mohamed Abualgasim Abdalhakam

2016-08-01

The aim of this study was to provide information about the trace element and heavy metals concentrations in black tea and tea leaves. 23 different samples were collected from the Sudanese local market. The collected samples were characterized as the most common used items in Sudan. The concentration of trace and heavy elements were determined using x-ray fluorescence (X RF) technique. The standard reference materials (IAEA-V-10) and hay (powder) were used to evaluate the accuracy of the analytical result. The measured values were found in agreement with the certified values. The elements determined were K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Pb, Br, Rb, and Sr. The average concentration of the elements is black tea were 2277.43, 7245.71, 1.11, 1025.29, 334.29, 6.88, 11.24, 9.47, 1.02, 7.08, 97.4 and 63.21 respectively while the average concentration of the elements in leaves tea were 2644.44, 8805.56, 1.02, 571.81, 295.44, 6.19, 10.69, 9.26, 0.91, 13.42, 63.03 and 67.14 respectively. The results showed an increase in the concentration of some elements such as calcium, chromium, manganese, iron, nickel, copper, zinc, bromine, rubidium and strontium (22500, 6.75, 48.9, 194, 4.37, 9,77, 24.9, 8.23, 7.79, 40,9) ppm respectively compared to certified values. Correlation between concentration of certain element and cluster analysis were preformed and the results compared with values of literature and the concentrations of some elements found to be similar.(Author)

Effect of γ-ray emission on transuranium element production cross sections in heavy ion reactions

International Nuclear Information System (INIS)

Il'inov, A.S.; Oganesyan, Yu.Ts.; Cherepanov, E.A.

1980-01-01

The effect of competition of the γ ray emission with neutron evaporation and of compound nuclei fission induced by heavy ion reactions on the production cross sections for transuranium elements is considered. It is shown that taking account of γ ray emission leads to the broadening of the excitation functions of the (HI, xny) reactions such as 18 O+ 238 U, 40 Ar+ 206 Pb, 40 Ar+ 207 Pb and 40 Ar+ 208 Pb reactions and to the displacement of their maximum toward the higher energies as well as to an increase of the absolute cross sections which is especially strong close to the fusion barrier. Cross sections for the radiative capture of heavy ions by a heavy target nucleus in 40 Ar+ 206 Pb, 40 Ar+ 208 Pb, 48 Ca+ 204 Pb and 48 Ca+ 208 Pb reactions are estimated

New isotopes of elements 104, 106 and 108 - highly stable superheavy nuclei

International Nuclear Information System (INIS)

Oganessian, Yuri

1994-01-01

In April 1993, as part of a joint Dubna-Livermore experiment at the Flerov Laboratory of Nuclear Reactions, new heavy isotopes of elements 104 and 106 were synthesized - 262 104, 265 106 and 266 106. Compared with the known even-even isotopes of elements 104 and 106, the new nuclei are characterized by their extraordinary high resistance to spontaneous fission. This is a direct proof of the macro-microscopic theory predictions in its version calculated by A.Sobiczewski et al. regarding a substantial increase in the half-lives of heavy nuclei near deformed shells with atomic number (Z) 108 and neutron number (N) 162.

Relative measurement of heavy elements in the bile gallbladder and gallstone

International Nuclear Information System (INIS)

Moosavi, K.; Vatankhah, S.; Salimi, J.

2006-01-01

Particle Induced X-Ray Emission is a suitable method for the analysis of biological samples in which heavy trace elements are contained in light matrix elements. It is very important to know which factors or probably elements act as initial seed and lead to growing the sands. The goal of this study was to compare the relative values of Fe/K, Cu/K and Zn/K for gallstones, gallbladder, and bile of a specific patient for studying the origination of forming the gallstones. Materials and Methods Human gallbladder, bile, and gallstone samples were obtained by surgical operation from 15 patients and are bombarded by 2.0 MeV energy proton beams produced by van de Graaff accelerator in vacuum. All .. the gallstones were chosen of pigment type of stones and, all the patients were adults. In contrast with conventional methods, the shell and center of the sands has been analyzed separately. The PIXE spectrum analysis was performed using the nonlinear least square fitting code AXIL and GUPIX. Results: The results of detected minor and trace elements shows that the precipitation of calcium salt in the bile lead to reduction of crystals' formation. Elemental comparison of pigment type of gallstone and bile shows that the concentration of calcium in the shell of the stones is four times more than that in the bile. Conclusion: Precipitation of the calcium from the saturated bile on the cholesterols as a seed of gallstones led to reduced sands formation. Analysis of the gallbladder of the same patients revealed no relation between elemental concentrations of bile and gallstones

Interannual heavy element and nutrient concentration trends in the top sediments of Venice Lagoon (Italy)

International Nuclear Information System (INIS)

Masiol, Mauro; Facca, Chiara; Visin, Flavia; Sfriso, Adriano; Pavoni, Bruno

2014-01-01

Highlights: • Heavy element concentrations in sediments of a transitional system were studied. • Element contamination in the recent years has generally declined. • Mercury and cadmium contamination still remain above the limits in hot spots. • The role of sediment resuspension due to anthropogenic activity is discussed. • A basic knowledge to assess the impact of the MOSE construction is provided. - Abstract: The elemental composition of surficial sediments of Venice Lagoon (Italy) in 1987, 1993, 1998 and 2003 were investigated. Zn and Cr concentrations resulted in higher than background levels, but only Cd and Hg were higher than legal quality standards (Italian Decree 2010/260 and Water Framework Directive 2000/60/EC). Contaminants with similar spatial distribution are sorted into three groups by means of correlation analysis: (i) As, Co, Cd, Cu, Fe, Pb, Zn; (ii) Ni, Cr; (iii) Hg. Interannual concentrations are compared by applying a factor analysis to the matrix of differences between subsequent samplings. A general decrease of heavy metal levels is observed from 1987 to 1993, whereas particularly high concentrations of Ni and Cr are recorded in 1998 as a consequence of intense clam fishing, subsequently mitigated by better prevention of illegal harvesting. Due to the major role played by anthropogenic sediment resuspension, bathymetric variations are also considered

Constraining the EOS of Neutron-Rich Nuclear Matter and Properties of Neutron Stars with Heavy-Ion Reactions

International Nuclear Information System (INIS)

Li Baoan; Worley, Aaron; Chen, L.-W.; Ko, Che Ming; Krastev, Plamen G.; Wen Dehua; Xiao Zhigang; Zhang Ming; Xu Jun; Yong Gaochan

2009-01-01

Heavy-ion reactions especially those induced by radioactive beams provide useful information about the density dependence of the nuclear symmetry energy, thus the Equation of State of neutron-rich nuclear matter, relevant for many astrophysical studies. The latest developments in constraining the symmetry energy at both sub- and supra-saturation densities from analyses of the isopsin diffusion and the π - /π + ratio in heavy-ion collisions using the IBUU04 transport model are discussed. Astrophysical ramifications of the partially constrained symmetry energy on properties of neutron star crusts, gravitational waves emitted by deformed pulsars and the w-mode oscillations of neutron stars are presented briefly.

Study of Particle Production and Nuclear Fragmentation in Relativistic Heavy-Ion Collisions in Nuclear Emulsions

CERN Multimedia

2002-01-01

% EMU11 \\\\ \\\\ We propose to use nuclear emulsions for the study of nuclear collisions of $^{207}$Pb, $^{197}$Au, and any other heavy-ion beams when they are available. We have, in the past, used $^{32}$S at 200A~GeV and $^{16}$O at 200A and 60A~GeV from CERN (Experiment EMU08) and at present the analysis is going on with $^{28}$Si beam from BNL at 14.5A~GeV. It will be important to compare the previous and the present investigations with the new $^{207}$Pb beam at 60-160A~GeV. We want to measure in nuclear emulsion, on an event by event basis, shower particle multiplicity, pseudorapidity density and density fluctuations of charged particles, charge multiplicity and angular distributions of projectile fragments, production and interaction cross-sections of heavily ionizing particles emitted from the target fragmentation. Special emphasis will be placed on the analysis of events produced in the central collisions which are selected on the basis of low energy fragments emitted from the target excitation. It woul...

On-line mass spectometry of nuclear reactions induced by heavy ions

International Nuclear Information System (INIS)

Saint Simon, M. de.

1977-01-01

The adaptation of the on-line mass-spectrometric technique to the special conditions of heavy ion induced reactions is described. The method is very selective about A and Z, even for the very heavy reaction products in counterpart of the limitation of its applications to the alkaline elements only. This method is used in order to study the effects of angular momentum brought by the projectile in the complete fusion process and in the following neutron evaporation. The analysis of excitation functions shows that the increase in mass of the projectile has not always the effect of increasing the rotation energy of the compound nucleus. The on-line mass spectrometry has allowed to study heavy ion induced fission. Measurements of complementary isotopic distributions of fission products make it possible to explain that the total number of neutrons emitted per fission can be always deduced from the fragment excitation energy. The study of the isotope distribution variance shows that the statistical model for fission is in good agreement with experimental results after taking into account the non-fusion processes [fr

Study of the light and heavy water leaks in nuclear reactors and development of techniques for their detection, location and estimation

International Nuclear Information System (INIS)

Bashiruddin Mahmood, S.

1979-01-01

In heavy water type nuclear reactors the detection and control of heavy water and light water escapes from different systems is of vital importance in the successful and economic operation of these type of plants. The high cost of heavy water makes it imperative to minimise all such escapes, in order to reduce the loss as well as the upgrading cost of downgraded collection recovered from the reactor building. Original methods and devices have been developed at the Karachi Nuclear Power Plant which successfully solve this problem. This report describes the constructional and operational features of these devices

Nuclear reactor fuel element with a cluster of parallel fuel pins

International Nuclear Information System (INIS)

Macfall, D.; Butterfield, C.E.; Butterfield, R.S.

1977-01-01

An improvement of the design of nuclear reactor fuel elements is described and illustrated by the example of a gas-cooled, graphite-moderated nuclear reactor. The fuel element has a cluster of parallel fuel pins with an outer can of structure material and an inner sleeve, as well as tie bars and spacing devices for all of these parts. The fuel element designed according to the invention allows lasy assembling and disassembling before and after use. During use, no relative axial motions are possible; nevertheless, the graphite sleeve is at no time subject to tensile stress: the individual parts are held in position from below by a single holding device. (UWI) [de

Nuclear fuel element containing particles of an alloyed Zr, Ti, and Ni getter material

International Nuclear Information System (INIS)

Grossman, L.N.; Levin, H.A.

1975-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed. The nuclear fuel element has disposed therein an alloy having the essential components of nickel, titanium and zirconium, and the alloy reacts with water, water vapor and reactive gases at reactor ambient temperatures. The alloy is disposed in the plenum of the fuel element in the form of particles in a hollow gas permeable container having a multiplicity of openings of size smaller than the size of the particles. The openings permit gases and liquids entering the plenum to contact the particles of alloy. The container is preferably held in the spring in the plenum of the fuel element. (Official Gazette)

Spectroscopy of very heavy nuclei with a view to study super-heavy nuclei; Spectroscopie de noyaux tres lourds en vue de l'etude des noyaux super-lourds

Energy Technology Data Exchange (ETDEWEB)

Khalfallah, F

2007-08-15

Within the recent years, the spectroscopic study of single particle orbitals of very heavy elements (VHE) has become possible with the development of increasingly efficient experimental setups. This allows us, through nuclear deformation, to access with these deformed nuclei to orbitals situated around the Fermi level in the spherical superheavy elements (SHE) and learn more about the nuclear structure of these nuclei. The aim of this work is the spectroscopic studies of heavy and very heavy elements. Because of the experimental difficulties associated with the fusion reactions in the VHE region, a detailed optimization studies is essential. Simulation of energy loss and angular straggling of these nuclei due to the interaction in the target and to neutron's evaporation was carried out and allowed us to optimize the angular acceptance of the separators according to the target thickness. An extensive survey and exploration in the VHE region was also conducted on the basis of cross section's systematics in the literature and simulations carried out using the statistical code Hivap. In this framework, the possible extension of the range of validity of a set of Hivap parameters was investigated. This work has enabled us to prepare a list of experiments of interest for the production of very heavy nuclei. In this thesis, our work was concentrated on the spectroscopy of the nuclei No{sup 256} et Rf{sup 256} for which two experimental proposals were accepted. The octupole deformations predicted in the actinides region is studied in another part of this thesis, a part witch is dedicated to the gamma spectroscopy of Pa{sup 223}. The data from a new experiment carried out using the Jurogam-Ritu-Great setup are analysed and compared to previous results. They confirm the octupole deformed shape in this nucleus. (author)

Safety Analysis of 'Older/Aged' Handling and Transportation Equipment for Heavy Loads, Radioactive Waste and Materials in Accordance with German Nuclear Standards KTA 3902, 3903 and 3905

International Nuclear Information System (INIS)

Macias, P.; Prucker, E.; Stang, W.

2006-01-01

The purpose of this paper is to present a general safety analysis of important handling and transportation processes and their related equipment ('load chains' consisting of cranes, load-bearing equipment and load-attaching points). This project was arranged by the responsible Bavarian ministry for environment, health and consumer protection (StMUGV) in agreement with the power plant operators of all Bavarian nuclear power plants to work out potential safety improvements. The range of the equipment (e.g. reactor building, crane, refuelling machine, load-bearing equipment and load-attaching points) covers the handling and transportation of fuel elements (e. g. with fuel flasks), heavy loads (e.g. reactor pressure vessel closure head, shielding slabs) and radioactive materials and waste (e.g. waste flasks, control elements, fuel channels, structure elements). The handling equipment was subjected to a general safety analysis taking into account the ageing of the equipment and the progress of standards. Compliance with the current valid requirements of the state of science and technology as required by German Atomic Act and particularly of the nuclear safety KTA-standards (3902, 3903 and 3905) was examined. The higher protection aims 'safe handling and transportation of heavy loads and safe handling of radioactive materials and waste' of the whole analysis are to avoid a criticality accident, the release of radioactivity and inadmissible effects on important technical equipment and buildings. The scope of the analysis was to check whether these protection aims were fulfilled for all important technical handling and transportation processes. In particularly the design and manufacturing of the components and the regulations of the handling itself were examined. (authors)

Extending Penning trap mass measurements with SHIPTRAP to the heaviest elements

International Nuclear Information System (INIS)

Block, M.; Ackermann, D.; Herfurth, F.; Hofmann, S.; Blaum, K.; Droese, C.; Marx, G.; Schweikhard, L.; Düllmann, Ch. E.; Eibach, M.; Eliseev, S.; Haettner, E.; Plaß, W. R.; Scheidenberger, C.; Heßberger, F. P.; Ramirez, E. Minaya; Nesterenko, D.

2013-01-01

Penning-trap mass spectrometry of radionuclides provides accurate mass values and absolute binding energies. Such mass measurements are sensitive indicators of the nuclear structure evolution far away from stability. Recently, direct mass measurements have been extended to the heavy elements nobelium (Z=102) and lawrencium (Z=103) with the Penning-trap mass spectrometer SHIPTRAP. The results probe nuclear shell effects at N=152. New developments will pave the way to access even heavier nuclides.

Nuclear interaction contribution to SEUs in heavy ion energy deposition in the ESA monitor

CERN Document Server

Bahamonde, Cristina

2013-01-01

The effects of nuclear interactions inducing Single Event Upsets in ESA SEU monitor are explored for heavy ion beams of different energies. The experimental and simulated results are compared, the possible causes of disagreement are suggested as well as the future steps to take.

Finite element modeling of AP1000 nuclear island

International Nuclear Information System (INIS)

Tinic, S.; Orr, R.

2003-01-01

The AP1000 is a standard design developed by Westinghouse and its partners for an advanced nuclear power plant utilizing passive safety features. It is based on the certified design of the AP600 and has been uprated to 1000 MWe. The plant has five principal building structures; the nuclear island, the turbine building; the annex building; the diesel generator building and the radwaste building. The nuclear island consists of the containment building (the steel containment vessel and the containment internal structures), the shield building, and the auxiliary building. These structures are founded on a common basemat and are collectively known as the nuclear island. This paper describes use of the general purpose finite element program ANSYS [2] in structural analyses and qualification of the AP1000 nuclear island buildings. It describes the modeling of the shield building and the auxiliary building and the series of analyses and the flow of information from the global analyses to the detailed analyses and building qualification. (author)

Dependence of heavy metal burnup on nuclear data libraries for fast reactors

CERN Document Server

Ohki, S

2003-01-01

Japan Nuclear Cycle Development Institute (JNC) is considering the highly burnt fuel as well as the recycling of minor actinide (MA) in the development of commercialized fast reactor cycle systems. Higher accuracy in burnup calculation is going to be required for higher mass plutonium isotopes ( sup 2 sup 4 sup 0 Pu, etc.) and MA nuclides. In the framework of research and development aiming at the validation and necessary improvements of fast reactor burnup calculation, we investigated the differences among the burnup calculation results with the major nuclear data libraries: JEF-2.2, ENDF/B-VI Release 5, JENDL-3.2, and JENDL-3.3. We focused on the heavy metal nuclides such as plutonium and MA in the central core region of a conventional sodium-cooled fast reactor. For main heavy metal nuclides ( sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 8 U, sup 2 sup 3 sup 9 Pu, sup 2 sup 4 sup 0 Pu, and sup 2 sup 4 sup 1 Pu), number densities after 1-cycle burnup did not change over one or two percent. Library dependence was re...

Nuclear molecular structure in heavy mass systems

International Nuclear Information System (INIS)

Arctaedius, T.; Bargholtz, C.

1989-04-01

A study is made of nuclear molecular configurations involving one heavy mass partner. The stability of these configurations to mass flow and to fission is investigated as well as their population in fusion reactions. It is concluded that shell effects in combination with the effects of angular momentum may be important in stabilizing certain configurations. A possible relation of these configurations to the so called superdeformed states is pointed out. The spectrum of rotational and vibrational trasitions within molecular configurations is investigated. For sufficiently mass-asymmetric systems the engergies of vibrational transitions are comparable to the neutron separation energy. Gamma radiation from such transitions may then be observable above the background of statistical transitions. The gamma spectrum and the directional distribution of the radioation following fusion reactions with 12 C and 16 O are calculated. (authors)

Porous nuclear fuel element with internal skeleton for high-temperature gas-cooled nuclear reactors

Science.gov (United States)

Youchison, Dennis L.; Williams, Brian E.; Benander, Robert E.

2013-09-03

Porous nuclear fuel elements for use in advanced high temperature gas-cooled nuclear reactors (HTGR's), and to processes for fabricating them. Advanced uranium bi-carbide, uranium tri-carbide and uranium carbonitride nuclear fuels can be used. These fuels have high melting temperatures, high thermal conductivity, and high resistance to erosion by hot hydrogen gas. Tri-carbide fuels, such as (U,Zr,Nb)C, can be fabricated using chemical vapor infiltration (CVI) to simultaneously deposit each of the three separate carbides, e.g., UC, ZrC, and NbC in a single CVI step. By using CVI, the nuclear fuel may be deposited inside of a highly porous skeletal structure made of, for example, reticulated vitreous carbon foam.

Nuclear fuel element nut retainer cup

International Nuclear Information System (INIS)

Walton, L.A.

1977-01-01

A typical embodiment has an end fitting for a nuclear reactor fuel element that is joined to the control rod guide tubes by means of a nut plate assembly. The nut plate assembly has an array of nuts, each engaging the respective threaded end of the control rod guide tubes. The nuts, moreover, are retained on the plate during handling and before fuel element assembly by means of hollow cylindrical locking cups that are brazed to the plate and loosely circumscribe the individual enclosed nuts. After the nuts are threaded onto the respective guide tube ends, the locking cups are partially deformed to prevent one or more of the nuts from working loose during reactor operation. The locking cups also prevent loose or broken end fitting parts from becoming entrained in the reactor coolant

Fuel element for nuclear reactors

International Nuclear Information System (INIS)

Cadwell, D.J.

1982-01-01

The invention concerns a fuel element for nuclear reactors with fuel rods and control rod guide tubes, where the control rod guide tubes are provided with flat projections projecting inwards, in the form of local deformations of the guide tube wall, in order to reduce the radial play between the control rod concerned and the guide tube, and to improve control rod movement. This should ensure that wear on the guide tubes is largely prevented which would be caused by lateral vibration of the control rods in the guide tubes, induced by the flow of coolant. (orig.) [de

Squids, supercurrents, and slope anomalies: Nuclear structure from heavy-ion transfer reactions

International Nuclear Information System (INIS)

Guidry, M.W.

1989-01-01

Within the past five years we have developed experimental techniques to study heavy-ion transfer reactions to high spin states in deformed nuclei. These methods have been turned into a quantitative tool to assess the influence of collective excitation on single-particle and pairing structure. I discuss some of the nuclear structure questions which are being answered in these experiments: How strong is ground state pairing? How does pairing change with angular momentum? Why is two-neutron transfer much stronger than expected at large radial separation? What is the evidence for a nuclear Josephson Effect? What is the evidence for a nuclear Berry phase effect (nuclear SQUID)? Why does one-neutron transfer populate much higher spins than would be naively expected? Conversely, why does two-neutron transfer populate much lower spins than anyone expected? The answer to each of these questions involves the influence of detailed nuclear structure on transfer reactions, and represents quantitative new information about the effect of angular momentum and excitation energy on many-body systems with a finite number of particles. 8 refs., 6 figs

Heavy element stable isotope ratios. Analytical approaches and applications

International Nuclear Information System (INIS)

Tanimizu, Masaharu; Sohrin, Yoshiki; Hirata, Takafumi

2013-01-01

Continuous developments in inorganic mass spectrometry techniques, including a combination of an inductively coupled plasma ion source and a magnetic sector-based mass spectrometer equipped with a multiple-collector array, have revolutionized the precision of isotope ratio measurements, and applications of inorganic mass spectrometry for biochemistry, geochemistry, and marine chemistry are beginning to appear on the horizon. Series of pioneering studies have revealed that natural stable isotope fractionations of many elements heavier than S (e.g., Fe, Cu, Zn, Sr, Ce, Nd, Mo, Cd, W, Tl, and U) are common on Earth, and it had been widely recognized that most physicochemical reactions or biochemical processes induce mass-dependent isotope fractionation. The variations in isotope ratios of the heavy elements can provide new insights into past and present biochemical and geochemical processes. To achieve this, the analytical community is actively solving problems such as spectral interference, mass discrimination drift, chemical separation and purification, and reduction of the contamination of analytes. This article describes data calibration and standardization protocols to allow interlaboratory comparisons or to maintain traceability of data, and basic principles of isotope fractionation in nature, together with high-selectivity and high-yield chemical separation and purification techniques for stable isotope studies.

Assembly for transport and storage of radioactive nuclear fuel elements

International Nuclear Information System (INIS)

Myers, G.

1978-01-01

The invention concerns the self-control of coolant deficiencies on the transport of spent fuel elements from nuclear reactors. It guarantees that drying out of the fuel elements is prevented in case of a change of volume of the fluid contained in storage tanks and accumulators and serving as coolant and shielding medium. (TK) [de

Determination of burn-up of irradiated nuclear fuels using mass spectrometry

International Nuclear Information System (INIS)

Jagadish Kumar, S.; Telmore, V.M.; Shah, R.V.; Sasi Bhushan, K.; Paul, Sumana; Kumar, Pranaw; Rao, Radhika M.; Jaison, P.G.

2017-01-01

Burn-up defined as the atom percent fission, is a vital parameter used for assessing the performance of nuclear fuel during its irradiation in the reactor. Accurate data on the actinide isotopes are also essential for the reliable accountability of nuclear materials and for nuclear safeguards. Both destructive and non-destructive methods are employed in the post-irradiation analysis for the burn-up measurements. Though non-destructive methods are preferred from the point view of remote handling of irradiated fuels with high radioactivity, they do not provide the high accuracy as achieved by the chemical analysis methods. Thus destructive radiochemical and chemical analyses are still the established reference methods for accurate and reliable burn-up determination of irradiated nuclear fuels. In the destructive method, burn-up of irradiated nuclear fuel is determined by correlating the amount of a fission product formed during irradiation with that of heavy elements. Thus the destructive experimental determination of burn-up involves the dissolution of irradiated fuel samples followed by the separation and determination of heavy elements and fission product(s) to be used as burn-up monitor(s). Another approach for the experimental determination of burn-up is based on the changes in the abundances of the heavy element isotopes. A widely accepted method for burn-up determination is based on stable "1"4"8Nd and "1"3"9La as burn-up monitors. Several properties such as non-volatility, nearly same yields for thermal fissions of "2"3"5U and "2"3"9Pu etc justifies the selection of "1"4"8Nd as a burn-up monitor

Nuclear fuel element containing strips of an alloyed Zr, Ti, and Ni getter material

International Nuclear Information System (INIS)

Grossman, L.N.; Packard, D.R.

1975-01-01

A nuclear fuel element for use in the core of a nuclear reactor is disclosed. The nuclear fuel element has disposed therein an alloy having the essential components of nickel, titanium and zirconium, and the alloy reacts with water, water vapor and reactive gases at reactor ambient temperatures. The alloy is disposed in the plenum of the fuel element in the form of strips and preferably the strips are positioned inside a helical member in the plenum. The position of the alloy strips permits gases and liquids entering the plenum to contact and react with the alloy strips. (U.S.)

Nuclear research with heavy ions. Annual progress report. January 1, 1980-December 31, 1980

Energy Technology Data Exchange (ETDEWEB)

Kaplan, M.

1980-10-01

The program of research is oriented towards experimental studies of the interactions between heavy ions and complex nuclei. These interactions are probed by detailed measurements of light-charged-particle emission using counter telescopes for atomic number and mass number identification. Singles measurements of the charged-particle energy spectra and angular distributions, together with coincidence correlations with heavy nuclear-reaction fragments, provide insight into the contributing reaction mechanisms. The application of the statistical model to the appropriate experimental data allows the determination of parameters necessary to calibrate the theory, and gives indications of dynamical control vs. equilibrium in the several degrees of freedom associated with the nuclear collisions. A large body of data are presented and discussed for /sup 40/Ar reactions with /sup 116/Sn, /sup 154/Sm, /sup 164/Dy, and /sup 197/Au targets. Complete results are also given for twelve reactions which produce /sup 194/Hg compound nuclei at several excitation energies.

Selected topics in nuclear structure

International Nuclear Information System (INIS)

Stachura, Z.

1984-09-01

19. winter school in Zakopane was devoted to selected topics in nuclear structure such as: production of spin resonances, heavy ions reactions and their applications to the investigation of high spin states, octupole deformations, excited states and production of new elements etc. The experimental data are ofen compared with theoretical predictions. Report contains 28 papers. (M.F.W.)

Estimation of atomic masses of heavy and superheavy elements

Energy Technology Data Exchange (ETDEWEB)

Uno, Masahiro [Ministry of Education, Science and Culture, Tokyo (Japan)

1997-07-01

To estimate unknown atomic masses of heavy and superheavy elements, three kinds of formula: FRDM (finite range droplet model by Moeller et al.), TUYY (an empirical formula by Tachibana et al.) and our KUTY are explained. KUTY estimates the crude shell energies of spherical nucleus from sum of single-particle energies. Then, the refined shell energies in due consideration of paring and deformation are obtained by mixing with the functions of the crude shell energies. Experimental values of U and Fm isotopes were compared with estimation mass of KUTY and FRDM. In the field with experimental values of U isotopes, the value of KUTY and FRDM separated the same difference from the experimental value. The behavior of KUTY and FRDM for Fm isotopes were same as that of U, but ETFSI deviated a little from the experimental values. (S.Y.)

Nuclear fuel element, and method of producing same

International Nuclear Information System (INIS)

Armijo, J.S.; Esch, E.L.

1986-01-01

This invention relates to an improvement in nuclear fuel elements having a composite container comprising a cladding sheath provided with a protective barrier of zirconium metal covering the inner surface of the sheath, rendering such fuel elements more resistant to hydrogen accumulation in service. The invention specifically comprises removing substantially all zirconium metal of the barrier layer from the part of the sheath surrounding and defining the plenum region. Thus the protective barrier of zirconium metal covers only the inner surface of the fuel container in the area immediately embracing the fissionable fuel material

Heavy flavours production in quark-gluon plasma formed in high energy nuclear reactions

Science.gov (United States)

Kloskinski, J.

1985-01-01

Results on compression and temperatures of nuclear fireballs and on relative yield of strange and charmed hadrons are given . The results show that temperatures above 300 MeV and large compressions are unlikely achieved in average heavy ion collision. In consequence, thermal production of charm is low. Strange particle production is, however, substantial and indicates clear temperature - threshold behavior.

Origin of the finite nuclear spin and its effect in intermediate energy heavy ion collisions

International Nuclear Information System (INIS)

Zhang Guoqiang; Cao Xiguang; Fu Yao

2012-01-01

The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC). The spin of maximal projectile-like fragment is found to depend strongly on impact parameter of a reaction system,while it relates weakly to the collision violence. Some interesting multi-fragmentation phenomena related to the spin are shown. We also found that the excitation energy in the de-excitation stage plays a robust role at the de-excitation stage in HIC. (authors)

Medical applications of nuclear physics and heavy-ion beams

International Nuclear Information System (INIS)

Alonso, Jose R.

2000-01-01

Isotopes and accelerators, hallmarks of nuclear physics, are finding increasingly sophisticated and effective applications in the medical field. Diagnostic and therapeutic uses of radioisotopes are now a $10B/yr business worldwide, with over 10 million procedures and patient studies performed every year. This paper will discuss the use of isotopes for these applications. In addition, beams of protons and heavy ions are being more and more widely used clinically for treatment of malignancies. To be discussed here as well will be the rationale and techniques associated with charged-particle therapy, and the progress in implementation and optimization of these technologies for clinical use

Structure of nuclear transition matrix elements for neutrinoless ...

Indian Academy of Sciences (India)

Abstract. The structure of nuclear transition matrix elements (NTMEs) required for the study of neutrinoless double- decay within light Majorana neutrino mass mechanism is disassembled in the PHFB model. The NTMEs are calculated using a set of HFB intrinsic wave functions, the reliability of which has been previously ...

Anatomy of double beta decay nuclear matrix elements

Energy Technology Data Exchange (ETDEWEB)

Vogel, Petr, E-mail: pxv@caltech.ed [Kellogg Radiation Laboratory 106-38 Caltech. Pasadena, CA 91125 (United States)

2009-06-01

The necessary ingredients for a realistic evaluation of the 0vbetabeta nuclear matrix elements are reviewed. It is argued that the short range nucleon correlations, nucleon finite size, and higher order nuclear currents need to be included in the calculation, even though a consensus on the best way to treat all of these effects has not been reached. Another positive development is the realization that the two alternative and complementary methods, the Quasiparticle Random Phase Approximation and the Nuclear Shell Model, agree on many aspects of the calculation, in particular on the competition, or cancelation, between the contribution of nuclear pairing on one hand, and the other pieces of interaction that result in admixtures of broken pairs or higher seniority states on the other hand. The relatively short range (r <= 2-3 fm) of the effective 0vbetabeta operator found in both methods is a consequence of that competition.

Nuclear fuel element and container

International Nuclear Information System (INIS)

Grubb, W.T.; King, L.H.

1981-01-01

The invention is based on the discovery that a substantial reduction in metal embrittlement or stress corrosion cracking from fuel pellet-cladding interaction can be achieved by the use of a copper layer or liner in proximity to the nuclear fuel, and an intermediate zirconium oxide barrier layer between the copper layer and the zirconium cladding substrate. The intermediate zirconia layer is a good copper diffusion barrier; also, if the zirconium cladding surface is modified prior to oxidation, copper can be deposited by electroless plating. A nuclear fuel element is described which comprises a central core of fuel material and an elongated container using the system outlined above. The method for making the container is again described. It comprises roughening or etching the surface of the zirconium or zirconium alloy container, oxidizing the resulting container, activating the oxidized surface to allow for the metallic coating of such surfaces by electroless deposition and further coating the activated-oxidized surface of the zirconium or zirconium alloy container with copper, iron or nickel or an alloy thereof. (U.K.)

Quasi-elastic scattering an alternative tool for mapping the fusion barriers for heavy-ion induced fusion reaction

International Nuclear Information System (INIS)

Behera, B.R.

2016-01-01

Heavy element synthesis through heavy-ion induced fusion reaction is an active field in contemporary nuclear physics. Exact knowledge of fusion barrier is one of the essential parameters for planning any experiments for heavy element production. Theoretically there are many models available to predict the exact barrier. Though these models are successful for predicting the fusion of medium mass nuclei, it somehow fails for predicting the exact location of barrier for fusion of heavy nuclei. Experimental determination of barrier for such reactions is required for future experiments for the synthesis of heavy elements. Traditionally fusion barrier is determined taking a double derivative of fusion excitation function. However, such method is difficult in case of fusion of heavy nuclei due to its very low fusion/capture cross section and its experimental complications. Alternatively fusion barrier can be determined by measuring the quasi-elastic cross section at backward angles. This method can be applied for determining the fusion barrier for the fusion of heavy nuclei. Experimental determination of fusion barrier by different methods and comparison of the fusion excitation function and quasi-elastic scattering methods for the determination of fusion barrier are reviewed. At IUAC, New Delhi recently a program has been started for the measurement of fusion barrier through quasi-elastic scattering methods. The experimental facility and the first results of the experiments carried out with this facility are presented. (author)

(d,p)-transfer induced fission of heavy radioactive beams

CERN Document Server

Veselsky, Martin

2012-01-01

(d,p)-transfer induced fission is proposed as a tool to study low energy fission of exotic heavy nuclei. Primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission offers a possibility for systematic study the low energy fission of heavy exotic nuclei at the ISOLDE.

Exploring Ultra-Heavy Cosmic Rays with the Trans-Iron Galactic Element Recorder (TIGER)

Science.gov (United States)

Link, Jason; Supertiger Collaboration

2017-01-01

Elements heavier than iron are primarily synthesized by neutron capture. These elements can be accelerated as cosmic-rays and measuring their abundances at Earth can yield information about galactic cosmic-rays' sources, the acceleration processes and the composition of the universe beyond the boundaries of our solar system. The Trans-Iron Galactic Element Recorder (TIGER) and its larger successor SuperTIGER was designed to measure the abundance of these ultra-heavy cosmic rays between Z=10 and Z=60. These detectors utilize scintillators with a wavelength shifter bar and PMT readout system as well as aerogel and acrylic Cherenkov detectors to identify the charge and energy of a particle and utilize a scintillating fiber hodoscope to provide trajectory information. In this talk I will review the results from this highly successful program, give the status for the next SuperTIGER flight planned for a December 2017 launch from Antarctica, and discuss the future direction of the program.

Volume concentration of 41 elements in ground level of atmosphere in Bratislava

International Nuclear Information System (INIS)

Florek, M.; Meresova, J.; Holy, K.; Sykora, I.; Frontasyeva, M. V.; Pavlov, S. S.

2006-01-01

The concentrations of 41 chemical elements (heavy metals, rare earths, and actinides) were determined in atmospheric aerosol using nuclear and related analytical techniques. The sampling location was in Bratislava (Slovak Republic). The main goal of this study is the quantification of the atmospheric pollution and its trend. The elemental content in filters was measured using instrumental neutron activation analysis at IBR-2 reactor in JINR Dubna and by atomic absorption spectrometry in Bratislava. The obtained results confirmed the decreasing trend of pollution by most of the heavy metals in Bratislava atmosphere, and they are compared with the contents of pollutants in atmosphere of other cities. We determined also the composition of clear filter materials. (authors)

Thin film analysis by instrumental heavy ion activation analysis using distributed recoil ranges of isotopic products

International Nuclear Information System (INIS)

Chowdhury, D.P.; Guin, R.; Saha, S.K.; Sudersanan, M.

2006-01-01

Thin foils (0.1 to 10 μm), metallic or polymeric, are frequently used in nuclear physics and chemistry experiments using ion beams from an accelerator. Very often it is important to know the major, minor and trace element composition of the foil. Several nuclear analytical techniques, namely RBS, ERDA, etc. are available for the near surface analysis. We have applied heavy ion activation analysis (HIAA) to explore the bulk composition of thin films. One of the difficulties in this method of thin film analysis is that the product nuclides from nuclear reaction come out of the sample surface due to high recoil energy. In thick sample, the recoiled nuclides are absorbed in the sample itself. This effect has been used to employ heavy ion activation for the analysis of thin films

Teaching nuclear science: A cosmological approach

International Nuclear Information System (INIS)

Viola, V.E.

1994-01-01

Theories of the origin of the chemical elements can be used effectively to provide a unifying theme in teaching nuclear phenomena to chemistry students. By tracing the element-producing steps that are thought to characterize the chemical evolution of the universe, one can introduce the basic principles of nuclear nomenclature, structure, reactions, energetics, and decay kinetics in a self-consistent context. This approach has the additional advantage of giving the student a feeling for the origin of the elements and their relative abundances in the solar system. Further, one can logically introduce all of the basic forces and particles of nature, as well as the many analogies between nuclear and atomic systems. The subjects of heavy-element synthesis, dating, and the practical applications of nuclear phenomena fit naturally in this scheme. Within the nucleosynthesis framework it is possible to modify the presentation of nuclear behavior to suit the audience--ranging from an emphasis on description for the beginning student to a quantitative theoretical approach for graduate students. The subject matter is flexible in that the basic principles can be condensed into a few lecture as part of a more general course of expanded into an entire course. The following sections describe this approach, with primary emphasis on teaching at the elementary level

Elastic and radiative heavy quark interactions in ultra-relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Uphoff, Jan; Fochler, Oliver; Xu, Zhe; Greiner, Carsten

2015-01-01

Elastic and radiative heavy quark interactions with light partons are studied with the partonic transport model named the Boltzmann approach to multiparton scatterings (BAMPSs). After calculating the cross section of radiative processes for finite masses in the improved Gunion–Bertsch approximation and verifying this calculation by comparing to the exact result, we study elastic and radiative heavy quark energy loss in a static medium of quarks and gluons. Furthermore, the full 3 + 1D space–time evolution of gluons, light quarks, and heavy quarks in ultra-relativistic heavy-ion collisions at the BNL Relativistic Heavy-Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC) are calculated with BAMPS including elastic and radiative heavy flavor interactions. Treating light and heavy particles on the same footing in the same framework, we find that the experimentally measured nuclear modification factor of charged hadrons and D mesons at the LHC can be simultaneously described. In addition, we calculate the heavy flavor evolution with an improved screening procedure from hard-thermal-loop calculations and confront the results with experimental data of the nuclear modification factor and the elliptic flow of heavy flavor particles at the RHIC and the LHC. (paper)

Heavy metals effects on forage crops yields and estimation of elements accumulation in plants as affected by soil

International Nuclear Information System (INIS)

Grytsyuk, N.; Arapis, G.; Perepelyatnikova, L.; Ivanova, T.; Vynograds'ka, V.

2006-01-01

Heavy metals (Cu, Cd, Pb, Zn) effect on the productivity of forage crops (clover and perennial cereal grasses) and their accumulation in plants, depending on the concentration of these elements in a soil, has been studied in micro-field experiments on three types of soil. The principle objective was to determine regularities of heavy metals migration in a soil-plant system aiming the estimation of permissible levels of heavy metals content in soils with the following elaboration of methods, which regulate the toxicants transfer to plants. Methods of field experiments, agrochemical and atomic absorption analysis were used. Results were statistically treated by Statistica 6.0, S-Plus 6. Experimental results have shown that the intensity of heavy metals accumulation in plants depends on the type of the soil, the species of plants, the physicochemical properties of heavy metals and their content in the soil. Logarithmic interdependency of heavy metals concentration in soils and their accumulation in plants is suggested. However, the strong correlation between the different heavy metals concentrations in the various soils and the yield of crops was not observed. Toxicants accumulation in crops decreased in time

Heavy metals effects on forage crops yields and estimation of elements accumulation in plants as affected by soil.

Science.gov (United States)

Grytsyuk, N; Arapis, G; Perepelyatnikova, L; Ivanova, T; Vynograds'ka, V

2006-02-01

Heavy metals (Cu, Cd, Pb, Zn) effect on the productivity of forage crops (clover and perennial cereal grasses) and their accumulation in plants, depending on the concentration of these elements in a soil, has been studied in micro-field experiments on three types of soil. The principle objective was to determine regularities of heavy metals migration in a soil-plant system aiming the estimation of permissible levels of heavy metals content in soils with the following elaboration of methods, which regulate the toxicants transfer to plants. Methods of field experiments, agrochemical and atomic absorption analysis were used. Results were statistically treated by Statistica 6.0, S-Plus 6. Experimental results have shown that the intensity of heavy metals accumulation in plants depends on the type of the soil, the species of plants, the physicochemical properties of heavy metals and their content in the soil. Logarithmic interdependency of heavy metals concentration in soils and their accumulation in plants is suggested. However, the strong correlation between the different heavy metals concentrations in the various soils and the yield of crops was not observed. Toxicants accumulation in crops decreased in time.

Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (Chinese Edition)

International Nuclear Information System (INIS)

2014-01-01

The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (Arabic Edition)

International Nuclear Information System (INIS)

2014-01-01

The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (Spanish Edition)

International Nuclear Information System (INIS)

2014-01-01

The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objeurity Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit

Objective and Essential Elements of a State's Nuclear Security Regime. Nuclear Security Fundamentals (French Edition)

International Nuclear Information System (INIS)

2014-01-01

The possibility that nuclear material or other radioactive material could be used for criminal purposes or intentionally used in an unauthorized manner cannot be ruled out in the current global situation. States have responded to this risk by engaging in a collective commitment to strengthen the protection and control of such material and to respond effectively to nuclear security events. States have agreed to strengthen existing instruments and have established new international legal instruments to enhance nuclear security worldwide. Nuclear security is fundamental in the management of nuclear technologies and in applications where nuclear material or other radioactive material is used or transported. Through its nuclear security programme, the IAEA supports States to establish, maintain and sustain an effective nuclear security regime. The IAEA has adopted a comprehensive approach to nuclear security. This recognizes that an effective national nuclear security regime builds on: the implementation of relevant international legal instruments; information protection; physical protection; material accounting and control; detection of and response to trafficking in such material; national response plans; and contingency measures. With its Nuclear Security Series, the IAEA aims to assist States in implementing and sustaining such a regime in a coherent and integrated manner. The IAEA Nuclear Security Series comprises: Nuclear Security Fundamentals, which include the objective and essential elements of a State's nuclear security regime; Recommendations; Implementing Guides; and Technical Guidance. Each State carries the full responsibility for nuclear security. Specifically, each State has the responsibility to provide for the security of nuclear material and other radioactive material and their associated facilities and activities; to ensure the security of such material in use, storage, or in transport; to combat illicit trafficking and the inadvertent movement of

Structure of nuclear transition matrix elements for neutrinoless ...

Indian Academy of Sciences (India)

Abstract. The structure of nuclear transition matrix elements (NTMEs) required for the study of neutrinoless double-β decay within light Majorana neutrino mass mechanism is disassembled in the PHFB model. The NTMEs are calculated using a set of HFB intrinsic wave functions, the reliability of which has been previously ...

Theory of nuclear heavy-ion direct transfer reactions

International Nuclear Information System (INIS)

Crowley, B.J.B.

1979-01-01

We review the distorted-wave approach to direct transfer reactions and draw attention to some of the shortcomings of current theories. We show that a reformulated form of the distorted-wave Born approximation (DWBA) for transfer can lead to important simplifications of the theory, which are valid for nuclear heavy-ion induced reactions at energies > or approx. =MeV/nucleon. In particular, in the semiclassical limit, it leads to a new and simple formula for the transfer t-matrix which includes all the essential physics while offering several important advantages over standard ''full-recoil finite-range'' DWBA. One such advantage is that the new formula is more transparent in that it is amendable to interpretation and analytical manipulation. At high-energy it is shown to reduce to one earlier deduced using eikonal-DWBA. The conditions for the validity of the new theory are discussed in detail. They are shown to be generally well satisfied for small-mass transfer between heavy-ions at energies at or above those particularly favour transfer (> or approx. =10 MeV/nucleon for transfer of valence nucleons). The restriction to small mass is not due to any recoil approximation; in fact, it is only a necessary restriction at certain energies. The theory treats recoil exactly. Consideration of the optimum dynamical conditions for transfer leads to a set of matching conditions. The presence of hitherto neglected absorption, arising from dynamical effects of poor matching, it suggested and qualitatively discussed. Condition under which such absorption may be neglected are derived. Results of numerical calculations are presented showing that the theory is capable of good agreement with standard full-recoil finite-range DWBA, and that it is capable of giving at least as good an account of experimental data for nucleon-transfer between heavy-ions at energies approx.10 MeV/nucleon

The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay

Science.gov (United States)

Cappuzzello, F.; Agodi, C.; Cavallaro, M.; Carbone, D.; Tudisco, S.; Lo Presti, D.; Oliveira, J. R. B.; Finocchiaro, P.; Colonna, M.; Rifuggiato, D.; Calabretta, L.; Calvo, D.; Pandola, L.; Acosta, L.; Auerbach, N.; Bellone, J.; Bijker, R.; Bonanno, D.; Bongiovanni, D.; Borello-Lewin, T.; Boztosun, I.; Brunasso, O.; Burrello, S.; Calabrese, S.; Calanna, A.; Chávez Lomelí, E. R.; D'Agostino, G.; De Faria, P. N.; De Geronimo, G.; Delaunay, F.; Deshmukh, N.; Ferreira, J. L.; Fisichella, M.; Foti, A.; Gallo, G.; Garcia-Tecocoatzi, H.; Greco, V.; Hacisalihoglu, A.; Iazzi, F.; Introzzi, R.; Lanzalone, G.; Lay, J. A.; La Via, F.; Lenske, H.; Linares, R.; Litrico, G.; Longhitano, F.; Lubian, J.; Medina, N. H.; Mendes, D. R.; Moralles, M.; Muoio, A.; Pakou, A.; Petrascu, H.; Pinna, F.; Reito, S.; Russo, A. D.; Russo, G.; Santagati, G.; Santopinto, E.; Santos, R. B. B.; Sgouros, O.; da Silveira, M. A. G.; Solakci, S. O.; Souliotis, G.; Soukeras, V.; Spatafora, A.; Torresi, D.; Magana Vsevolodovna, R.; Yildirim, A.; Zagatto, V. A. B.

2018-05-01

The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. First experimental results obtained at the INFN-LNS laboratory for the 40Ca(18O,18Ne)40Ar reaction at 270MeV give an encouraging indication on the capability of the proposed technique to access relevant quantitative information. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the acceleration of the required high resolution and low emittance heavy-ion beams and the latter is the large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the experimental resolution and sensitivity required for the accurate measurement of the DCE cross sections at forward angles. However, the tiny values of such cross sections and the resolution requirements demand beam intensities much larger than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities in this perspective is part of the NUMEN project and will be discussed in the article.

Proposal of a system for fuel elements inspection of CDTN TRIGA nuclear reactor

International Nuclear Information System (INIS)

Rodrigues, Rogerio Rivail; Mesquita, Amir Zacarias

2013-01-01

The CDTN has in its facilities a TRIGA-type nuclear reactor. The reactor's cooling water must be treated and managed with the goal of keeping its low conductivity to minimize corrosion of the reactor components, mainly of fuel elements (FE), and reduce the level of radioactivity. The aim of this paper is to present a proposal for the development of a system for verification of some possible leaks in FE nuclear research reactors, based on the sipping test. This type of testing is a way to check for leaks of fission products from fuel element of nuclear research reactor. In the future, when the test will do, it will have a correlation between the components found in the reactor cooling water pool and integrity of nuclear fuel elements. The device development and its application will be presented here, covering results that were not previously investigated yet, giving originality to this project. (author)

Canning and inspection system for nuclear reactor fuel and reflector elements

International Nuclear Information System (INIS)

Goldman, L.A.; Hawke, B.C.

1980-01-01

A system is disclosed for canning, inspecting and transferring to a storage area fuel and reflector elements from a nuclear reactor. The system includes a transfer chute, environmental chamber, conveyor and canning mechanism operative to remove and replace closures on containers into which fuel and reflector elements are inserted or from which stored elements are removed while maintaining a sealed gaseous environment and permitting visual and mechanical inspection of the elements by an operator located in a remote shielded area

Fusion option to dispose of spent nuclear fuel and transuranic elements

International Nuclear Information System (INIS)

Gohar, Y.

2000-01-01

The fusion option is examined to solve the disposition problems of the spent nuclear fuel and the transuranic elements. The analysis of this report shows that the top rated solution, the elimination of the transuranic elements and the long-lived fission products, can be achieved in a fusion reactor. A 167 MW of fusion power from a D-T plasma for sixty years with an availability factor of 0.75 can transmute all the transuranic elements and the long-lived fission products of the 70,000 tons of the US inventory of spent nuclear fuel generated up to the year 2015. The operating time can be reduced to thirty years with use of 334 MW of fusion power, a system study is needed to define the optimum time. In addition, the fusion solution eliminates the need for a geological repository site, which is a major advantage. Meanwhile, such utilization of the fusion power will provide an excellent opportunity to develop fusion energy for the future. Fusion blankets with a liquid carrier for the transuranic elements can achieve a transmutation rate for the transuranic elements up to 80 kg/MW.y of fusion power with k eff of 0.98. In addition, the liquid blankets have several advantages relative to the other blanket options. The energy from this transmutation is utilized to produce revenue for the system. Molten salt (Flibe) and lithium-lead eutectic are identified as the most promising liquids for this application, both materials are under development for future fusion blanket concepts. The Flibe molten salt with transuranic elements was developed and used successfully as nuclear fuel for the molten salt breeder reactor in the 1960's

Recent developments in heavy-ion fusion reactions around the Coulomb barrier

Directory of Open Access Journals (Sweden)

Hagino K.

2016-01-01

Full Text Available The nuclear fusion is a reaction to form a compound nucleus. It plays an important role in several circumstances in nuclear physics as well as in nuclear astrophysics, such as synthesis of superheavy elements and nucleosynthesis in stars. Here we discuss two recent theoretical developments in heavy-ion fusion reactions at energies around the Coulomb barrier. The first topic is a generalization of the Wong formula for fusion cross sections in a single-channel problem. By introducing an energy dependence to the barrier parameters, we show that the generalized formula leads to results practically indistinguishable from a full quantal calculation, even for light symmetric systems such as 12C+12C, for which fusion cross sections show an oscillatory behavior. We then discuss a semi-microscopic modeling of heavy-ion fusion reactions, which combine the coupled-channels approach to the state-of-the-art nuclear structure calculations for low-lying collective motions. We apply this method to subbarrier fusion reactions of 58Ni+58Ni and 40Ca+58Ni systems, and discuss the role of anharmonicity of the low-lying vibrational motions.

Memory list for the ordering of nuclear fuel elements with UO2 fuel

International Nuclear Information System (INIS)

1977-01-01

The memory list will help to simplify and speed up the technical procedure of fuel element supply for nuclear reactors. Operators of nuclear power plants take great interest in the latest state of thechnology, if sufficiently tested, being applied with regard to material, manufacturing and testing methods. In order to obtain an unlimited availability of the nuclear plant in the future, this application of technology should be taken care of when designing and producing fuel elements. When ordering fuel elements special attention should be drawn to the interdependence of reactor and fuel element with reqard to design and construction, about which, howevers, no further details are given. When ordering fuel elements the operator give the producer all design data of the reactor core and the fuel elements as well as the planned operation mode. He also hands in the respective graphs and the required conditions for design so that a correct and detailed offer can be supplied. An exemplary extent of supply is shown in the given memory list. The regulations required herefore on passing technical material to the fuel element producers have to be established by agreements made by the customer. The order to be given should be itemized as follows: requirements, quality controland quality assurance, warranties and conditions, limits and extent of supply, terms of delivery. (orig./HP) [de

Study of candu fuel elements irradiated in a nuclear power plant

International Nuclear Information System (INIS)

Ionescu, S.; Uta, O.; Mincu, M.; Anghel, D.; Prisecaru, I.

2015-01-01

The object of this work is the behaviour of CANDU fuel elements after service in nuclear power plant. The results are analysed and compared with previous result obtained on unirradiated samples and with the results obtained on samples irradiated in the TRIGA reactor of INR Pitesti. Zircaloy-4 is the material used for CANDU fuel sheath. The importance of studying its behaviour results from the fact that the mechanical properties of the CANDU fuel sheath suffer modifications during normal and abnormal operation. In the nuclear reactor, the fuel elements endure dimensional and structural changes as well as cladding oxidation, hydriding and corrosion. These changes can lead to defects and even to the loss of integrity of the cladding. This paper presents the results of examinations performed in the Post Irradiation Examination Laboratory (PIEL) of INR Pitesti on samples from fuel elements after they were removed out of the nuclear power plant: - dimensional and macrostructural characterization; - microstructural characterization by metallographic analyses; - determination of mechanical properties; - fracture surface analysis by scanning electron microscopy (SEM). A full set of non-destructive and destructive examinations concerning the integrity, dimensional changes, oxidation, hydriding and mechanical properties of the cladding was performed. The obtained results are typical for CANDU 6-type fuel. The obtained data could be used to evaluate the security, reliability and nuclear fuel performance, and for the improvement of the CANDU fuel. (authors)

Safe management of actinides in the nuclear fuel cycle: Role of mineralogy

International Nuclear Information System (INIS)

Ewing, R.C.

2011-01-01

During the past 60 years, more than 1800 metric tonnes of Pu, and substantial quantities of the 'minor' actinides, such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranium elements can be a source of energy in fission reactions (e.g., 239 Pu), a source of fissile material for nuclear weapons (e.g., 239 Pu and 237 Np), and of environmental concern because of their long-half lives and radiotoxicity (e.g., 239 Pu and 237 Np). There are two basic strategies for the disposition of these heavy elements: (1) to 'burn' or transmute the actinides using nuclear reactors or accelerators; (2) to 'sequester' the actinides in chemically durable, radiation-resistant materials that are suitable for geologic disposal. There has been substantial interest in the use of actinide-bearing minerals, especially isometric pyrochlore, A 2 B 2 O 7 (A rare earths; B = Ti, Zr, Sn, Hf), for the immobilization of actinides, particularly plutonium, both as inert matrix fuels and nuclear waste forms. Systematic studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high doses of alpha-decay event damage. Recent developments in our understanding of the properties of heavy element solids have opened up new possibilities for the design of advanced nuclear fuels and waste forms. (author)

Determination of heavy water in heavy water - light water mixtures

International Nuclear Information System (INIS)

Sanhueza M, A.

1986-01-01

A description about experimental methodology to determine isotopic composition of heavy water - light water mixtures is presented. The employed methods are Nuclear Magnetic Resonance Spectroscopy, for measuring heavy water concentrations from 0 to 100% with intervals of 10% approx., and mass Spectrometry, for measuring heavy water concentrations from 0.1 to 1% with intervals of 0.15% approx., by means of an indirect method of Dilution. (Author)

Heavy metals-bioremediation by highly radioresistant Deinococcus radiodurans biofilm prospective use in nuclear reactor decontamination

International Nuclear Information System (INIS)

Shukla, Sudhir K.; Subba Rao, T.

2015-01-01

Over the past few decades, rapid growth of chemical industries have enhanced the heavy metal contamination in water, thereby raising environmental concerns. In the nuclear power industry, decontamination procedure also generates radioactive heavy metal containing wastes. Radio-resistant Deinococcus radiodurans R1 is reported to be a potential candidate for the treatment of low active waste material. To use any bacterium for bioremediation purpose, knowledge about its biofilm production characteristics is a prerequisite. This is because biofilm-mediated bioremediation processes are more efficient as compared to processes mediated by their planktonic counterparts. However, so far there are no reports on the biofilm producing capability of D. radiodurans. We observed that tagging of D. radiodurans by a plasmid harbouring gfp and kan R conferred significant biofilm producing property to the bacterium. Chemical analysis of biofilm matrix components produced by D. radiodurans showed that the matrix consists primarily of proteins and carbohydrates with small amount of extracellular DNA (eDNA). Further, we studied the effect of Ca 2+ on D. radiodurans biofilm formation and it was observed that D. radiodurans biofilm formation was enhanced at higher concentrations of Ca 2+ . We investigated the capability of D. radiodurans biofilm to remove the heavy metals Co and Ni from synthetic waste streams. Results showed that Ca 2+ enhanced the bioremediation of both heavy metals (Co, Ni) by D. radiodurans biofilms in a highly significant manner. In the presence of 50 mM Ca 2+ 35% Co removal and 25% Ni removal was observed, when compared to biofilm grown in the absence of Ca 2+ , which showed mere 7% Co and 3% Ni removal, respectively. The results showed that the presence of Ca 2+ significantly enhanced exopolysaccharide and eDNA (both negatively charged) production in the biofilm matrix. This indicated adsorption could be the major mechanism behind enhanced biofilm mediated removal

Superheavy Element Synthesis And Nuclear Structure

International Nuclear Information System (INIS)

Ackermann, D.; Block, M.; Burkhard, H.-G.; Heinz, S.; Hessberger, F. P.; Khuyagbaatar, J.; Kojouharov, I.; Mann, R.; Maurer, J.; Antalic, S.; Saro, S.; Venhart, M.; Hofmann, S.; Leino, M.; Uusitalo, J.; Nishio, K.; Popeko, A. G.; Yeremin, A. V.

2009-01-01

After the successful progress in experiments to synthesize superheavy elements (SHE) throughout the last decades, advanced nuclear structure studies in that region have become feasible in recent years thanks to improved accelerator, separation and detection technology. The means are evaporation residue(ER)-α-α and ER-α-γ coincidence techniques complemented by conversion electron (CE) studies, applied after a separator. Recent examples of interesting physics to be discovered in this region of the chart of nuclides are the studies of K-isomers observed in 252,254 No and in 270 Ds.

The permission of transport of irradiated nuclear fuel elements

International Nuclear Information System (INIS)

Klomberg, T.J.M.

2000-01-01

In July and October 2000 the Dutch government granted permits for the transportation of irradiated nuclear fuel elements. The environmental organization Greenpeace objected against the permit, but that was rejected by the Dutch Council of State. A brief overview is given of the judgements and the state-of-the-art with respect to the transportation of the elements from Dutch reactors and storage facilities in Petten, Dodewaard and Borssele to Cogema in La Hague, France and BNFL in Sellafield, England

Estimation of Heavy Elements Pollution in Sea Plants (Algae) by Using Neutron Activation Analysis

International Nuclear Information System (INIS)

El-Ghondi, A. A.; El-Mismary, Y. A.; Etwir, R. H.; Machiouf, M. A.; Ben Shaban, Y.; Abia, R.

2007-01-01

The total content of trace elements were determined in 50 samples of sea plants (macro algae) collected from Tripoli coast area (Tajura, El schab, Dat Elemad ) in Libya. The samples were investigated as an indication of heavy elements pollution. In this paper, the total amounts of Zn, Sc, Fe, Co, Cr, Ba, Cs, Sb, Rb, and Hf concentration were determined by using Neutron Activation Analysis in Tajura research center. High levels of Zn and Cr and slightly increasing in amount of Co and Fe are considered as normal values comparing with polluted area particularly with Fe and Co in investigated samples. Statistical calculation of the results have shown a positive relationship between the contents of Ba, Sc, Hf, Cr and Fe-Sb but no relation with Zn and other investigated trace elements contents. Further investigation should be carried out to confirm these findings and correlate them to source attribution.

Two-loop massive operator matrix elements for unpolarized heavy flavor production to O({epsilon})

Energy Technology Data Exchange (ETDEWEB)

Bierenbaum, I.; Bluemlein, J.; Klein, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Schneider, C. [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation

2008-02-15

We calculate the O({alpha}{sup 2}{sub s}) massive operator matrix elements for the twist-2 operators, which contribute to the heavy flavor Wilson coefficients in unpolarized deeply inelastic scattering in the region Q{sup 2}>>m{sup 2}, up to the O({epsilon}) contributions. These terms contribute through the renormalization of the O({alpha}{sup 3}{sub s}) heavy flavor Wilson coefficients of the structure function F{sub 2}(x,Q{sup 2}). The calculation has been performed using light-cone expansion techniques without using the integration-by-parts method. We represent the individual Feynman diagrams by generalized hypergeometric structures, the {epsilon}-expansion of which leads to infinite sums depending on the Mellin variable N. These sums are finally expressed in terms of nested harmonic sums using the general summation techniques implemented in the Sigma package. (orig.)

Theoretical studies in nuclear reactions and nuclear structure

International Nuclear Information System (INIS)

Wallace, S.J.

1991-05-01

This report discusses topics in the following areas: Hadronic structure; hadrons in nuclei; hot hadronic matter; relativistic nuclear physics and NN interaction; leptonic emissions from high-Z heavy ion collisions; theoretical studies of heavy ion dynamics; nuclear pre-equilibrium reactions; classical chaotic dynamics and nuclear structure; and, theory of nuclear fission

Recent studies of nuclear and chemical properties of elements 103, 104 and 105

International Nuclear Information System (INIS)

Hoffman, D.C.

1990-08-01

Information obtained since 1983 on the nuclear and chemical properties of element 103, the last on the actinide series, and elements 104 and 105, at the beginning of the transactinide series, is reviewed. Their chemical properties are compared with their lanthanide and lighter group 4 and 5 homologs and evidence for possible relativistic effects is discussed. The current knowledge of the nuclear properties of these elements and how these affect of the study of chemical properties is discussed. Some of the challenges involved in the study of short-lived isotopes which can only be produced an ''atom-at-a-time'' at an appropriate accelerator and the prognosis for future studies of these and still heavier elements are considered. 40 refs., 4 figs

Heavy flavor production in nuclear collisions

CERN Document Server

Armesto-Pérez, Nestor; Capella, A; Pajares, C; Salgado, C A

2001-01-01

Heavy flavor production off nuclei is studied in the small x/sub F/ region of the produced heavy system. Corrections to the usually employed perturbative QCD factorization formula are considered in the framework of the Glauber-Gribov model. Transition from low to high energies is taken into account by using finite energy cutting rules. The low energy limit of the obtained results coincides with the probabilistic formula usually employed for quarkonium absorption. At finite energies both rescattering of the heavy flavor and corrections to nucleon parton densities inside nuclei appear, the latter also affecting lepton pair production. It turns out that at asymptotic energies both open heavy flavor and quarkonium are equally absorbed. The numerical differences between the results obtained with the probabilistic formula and the exact one are <20% up to LHC energies, and ~1/2% at SPS energies. (18 refs).

Drying of heavy water system and works of charging heavy water in Fugen

International Nuclear Information System (INIS)

Matsushita, Tadashi; Iijima, Setsuo

1980-01-01

The advanced thermal reactor ''Fugen'' is the first heavy water-moderated, boiling light water-cooled nuclear reactor for power generation in Japan. It is a large heavy water reactor having about 130 m 3 of heavy water inventory and about 300 m 3 of helium space as the cover gas of the heavy water system. The heavy water required was purchased from FRG, which had been used for the power output test in the KKN, and the quality was 99.82 mol % mean heavy water concentration. The concentration of heavy water for Fugen used for the nuclear design is 99.70 mol%, and it was investigated how heavy water can be charged without lowering the concentration. The matters of investigation include the method of bringing the heavy water and helium system to perfect dryness after washing and light water test, the method of confirming the sufficient dryness to prevent the deterioration, and the method of charging heavy water safely from its containers. On the basis of the results of investigation, the actual works were started. The works of drying the heavy water and helium system by vacuum drying, the works of sampling heavy water and the result of the degree of deterioration, and the works of charging heavy water and the measures to the heavy water remaing in the containers are described. All the works were completed safely and smoothly. (J.P.N.)

Store for burnt-up fuel elements of nuclear reactors

International Nuclear Information System (INIS)

Kumpf, H.

1981-01-01

Burnt-up fuel elements of nuclear reactors have to be cooled during storage. For this reason the boxes which surround the fuel elements can have cooling air flowing round them in natural flow. This air is taken through the walls of a storage building through zones of parallel pipes, whose diameter and spacing are in the ratio of 1 : 0.5 to 1 : 2. The pipes have dust filters. Prefilters with fan drive are situated in parallel with the inlet pipe zones. (orig.) [de

Study on the high-precision laser welding technology of nuclear fuel elements processing

Energy Technology Data Exchange (ETDEWEB)

Kim, Soo Sung; Yang, M. S.; Kim, W. K.; Lee, D. Y

2001-01-01

The proper welding method for appendage of bearing pads and spacers of PHWR nuclear fuel elements is considered important in respect to the soundness of weldments and the improvement of the performance of nuclear fuels during the operation in reactor. The probability of welding defects of the appendage parts is mostly apt to occur and it is connected directly with the safty and life prediction of the nuclear reactor in operation. Recently there has been studied all over the world to develope welding technology by laser in nuclear fuel processing, and the appendage of bearing pads and spacers of PHWR nuclear fuel elements. Therefore, the purpose of this study is to investigate the characteristics of the laser welded specimens and make some samples for the appendage of bearing pads of PHWR nuclear fuel elements. This study will be also provide the basic data for the fabrications of the appendage of bearing pads and spacers. Especially the laser welding is supposed to be used in the practical application such as precise materials manufacturing fields. In this respect this technology is not only a basic advanced technology with wide applications but also likely to be used for the development of directly applicable technologies for industries, with high potential benefits derived in the view point of economy and industry.

Study on the high-precision laser welding technology of nuclear fuel elements processing

International Nuclear Information System (INIS)

Kim, Soo Sung; Yang, M. S.; Kim, W. K.; Lee, D. Y.

2001-01-01

The proper welding method for appendage of bearing pads and spacers of PHWR nuclear fuel elements is considered important in respect to the soundness of weldments and the improvement of the performance of nuclear fuels during the operation in reactor. The probability of welding defects of the appendage parts is mostly apt to occur and it is connected directly with the safty and life prediction of the nuclear reactor in operation. Recently there has been studied all over the world to develope welding technology by laser in nuclear fuel processing, and the appendage of bearing pads and spacers of PHWR nuclear fuel elements. Therefore, the purpose of this study is to investigate the characteristics of the laser welded specimens and make some samples for the appendage of bearing pads of PHWR nuclear fuel elements. This study will be also provide the basic data for the fabrications of the appendage of bearing pads and spacers. Especially the laser welding is supposed to be used in the practical application such as precise materials manufacturing fields. In this respect this technology is not only a basic advanced technology with wide applications but also likely to be used for the development of directly applicable technologies for industries, with high potential benefits derived in the view point of economy and industry

Can alchemy solve the nuclear waste problem?

International Nuclear Information System (INIS)

Gibson, D.

1991-01-01

One new technology being explored to deal with highly radioactive elements that remain dangerous for thousands of years is transmutation-a modern twist on the ancient idea of transforming one element into another. This modern version of transmutation is not a new concept: transmutation is the essence of nuclear reactions. The latest idea is to harness the process not to create an explosive chain reaction, as in a nuclear weapon, or even primarily to generate power, as in a nuclear power reactor, but to transform dangerous radionuclides into less harmful elements. Last year a Los Alamos team began looking into using a particle accelerator instead of a conventional nuclear reactor to drive the transmutation process. Accelerator transmutation is being pursued elsewhere as well. The Los Alamos project envisions using a linear accelerator to generate extremely high intensities of neutrons for transmutation. The most powerful medium-energy accelerator in the world is located at Los Alamos-the Meson Physics Facility. All major components have been demonstrated individually but have yet to be tested in an integrated unit; when built, these accelerators will produce very intense beams of fast-moving protons. The beams will be directed into heavy-metal targets of lead and bismuth, where each proton will knock-out more than 50 neutrons from the target atoms. The scheme calls for the target to be surrounded by a moderator of heavy water, which would slow the neutrons so they could more easily be captured by the waste products to be transmuted-the lightweight fission products and the heavy actinides. These substances would be carried in a molten salt solution in a separate loop through the moderator. Circulation of both the moderator and the salt loop would dissipate the heat generated by the fission process in what is essentially a subcritical reactor. The paper discusses the advantages of this process and summarizes related research

Nuclear rotational population patterns in heavy-ion scattering and transfer reactions

Energy Technology Data Exchange (ETDEWEB)

Rasmussen, J O; Stoyer, M A [Lawrence Berkeley Lab., CA (USA); Canto, L F; Donangelo, R [Universidade Federal do Rio de Janeiro, RJ (Brazil); Ring, P [Technische Univ. Muenchen, Garching (Germany, F.R.). Fakultaet fuer Physik

1991-05-01

A model of {sup 239}Pu with decoupled neutron is used for theoretical calculations of rotational population patterns in heavy ion inelastic scattering and one-neutron transfer reactions. The system treated in {sup 90}Zr on {sup 239}Pu at the near-barrier energy of 500 MeV and backscattering angles of 180deg and 140deg. The influence of the complex nuclear optical potential is seen to be very strong, and the Nilsson wave function of the odd neutron produces a distinctive pattern in the transfer reaction. (orig.).

The Distribution of Heavy Element From Fish, Algae, Water and Sea Sediment In Lemahabang Muria Peninsula

International Nuclear Information System (INIS)

Sukirno; J-Djati-Pramana; Sumining

2005-01-01

The analysis of heavy elements from fish, algae, water and sea sediments in Muria peninsula Jepara has been carried out using neutron activation analysis (NAA) method. Irradiation of sample was carried out for twelve hours with using Lazy Susan facility with neutron flux of 0.585x10 11 n.cm -2 .S -1 . Comparative mode of measurement was used for avoiding the effects of neutron flux parameters on the results. The result on analysis using gamma spectrometry with a Ge(Li) detector showed that there were 6 elements which observed. Those elements contained in algae, fish, water and sea sediment were Co, Sb, Sc, Fe, Cr and Cd. The highest element concentration found in sediment was Fe of 65.625 ± 3.12 % and the lowest was Co of 0.00256 ± 0.00045 μg/g for sea water. This method give precision and relative accuracy of < 10 % for all elements. (author)

Public information - the crucial element in nuclear power acceptance

International Nuclear Information System (INIS)

Hayes, R.; Middlemiss, N.

1996-01-01

The British nuclear industry approach to the public information is described as the crucial element in nuclear power acceptance. The industry need to be a reliable, trustworthy source of information. There is evidence that when issues are examined in court or in quasi-judicial contexts, the public gains a better appreciation of the issues. The media report both sides of debate more evenly. Therefore the best way to deal with the most hostile opposition may be to take into a legal framework, rather than engage in hand-to-hand battle

Public information - the crucial element in nuclear power acceptance

Energy Technology Data Exchange (ETDEWEB)

Hayes, R; Middlemiss, N [British Nuclear Industry Forum, London (United Kingdom)

1996-07-01

The British nuclear industry approach to the public information is described as the crucial element in nuclear power acceptance. The industry need to be a reliable, trustworthy source of information. There is evidence that when issues are examined in court or in quasi-judicial contexts, the public gains a better appreciation of the issues. The media report both sides of debate more evenly. Therefore the best way to deal with the most hostile opposition may be to take into a legal framework, rather than engage in hand-to-hand battle.

Low Cost Nuclear Thermal Rocket Cermet Fuel Element Environment Testing

Science.gov (United States)

Bradley, David E.; Mireles, Omar R.; Hickman, Robert R.

2011-01-01

Deep space missions with large payloads require high specific impulse (Isp) and relatively high thrust in order to achieve mission goals in reasonable time frames. Conventional, storable propellants produce average Isp. Nuclear thermal rockets (NTR) capable of high Isp thrust have been proposed. NTR employs heat produced by fission reaction to heat and therefore accelerate hydrogen which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000K) and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high temperature hydrogen exposure on fuel elements is limited. The primary concern is the mechanical failure of fuel elements which employ high-melting-point metals, ceramics or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. It is not necessary to include fissile material in test samples intended to explore high temperature hydrogen exposure of the structural support matrices. A small-scale test bed designed to heat fuel element samples via non-contact RF heating and expose samples to hydrogen is being developed to assist in optimal material and manufacturing process selection without employing fissile material. This paper details the test bed design and results of testing conducted to date.

Study of Superheavy Elements

International Nuclear Information System (INIS)

Hofmann, Sigurd

2007-01-01

The nuclear shell model predicts that the next doubly magic shell-closure beyond 208 Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical 'SuperHeavy Elements' (SHEs). Experimental methods are described, which allowed for the identification of elements produced on a cross-section level of about 1 pb. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decay properties as well as reaction cross-sections are compared with results of theoretical investigations. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques, as for instance the precise mass measurement of the produced nuclei using ion traps. At increased sensitivity, the detailed exploration of the region of spherical SHEs will start, after first steps on the island were made in recent years. (Author)

Contamination and Health Risks from Heavy Metals (Cd and Pb and Trace Elements (Cu and Zn in Dairy Products

Directory of Open Access Journals (Sweden)

Hamid Reza Ghafari

2017-08-01

Conclusion: Considering the serious contamination of some brands of butter and cheese by Cu and Pb, a control of heavy metals and trace elements levels during the whole production processing of dairy products must be applied.

Nuclear

International Nuclear Information System (INIS)

2014-01-01

This document proposes a presentation and discussion of the main notions, issues, principles, or characteristics related to nuclear energy: radioactivity (presence in the environment, explanation, measurement, periods and activities, low doses, applications), fuel cycle (front end, mining and ore concentration, refining and conversion, fuel fabrication, in the reactor, back end with reprocessing and recycling, transport), the future of the thorium-based fuel cycle (motivations, benefits and drawbacks), nuclear reactors (principles of fission reactors, reactor types, PWR reactors, BWR, heavy-water reactor, high temperature reactor of HTR, future reactors), nuclear wastes (classification, packaging and storage, legal aspects, vitrification, choice of a deep storage option, quantities and costs, foreign practices), radioactive releases of nuclear installations (main released radio-elements, radioactive releases by nuclear reactors and by La Hague plant, gaseous and liquid effluents, impact of releases, regulation), the OSPAR Convention, management and safety of nuclear activities (from control to quality insurance, to quality management and to sustainable development), national safety bodies (mission, means, organisation and activities of ASN, IRSN, HCTISN), international bodies, nuclear and medicine (applications of radioactivity, medical imagery, radiotherapy, doses in nuclear medicine, implementation, the accident in Epinal), nuclear and R and D (past R and D programmes and expenses, main actors in France and present funding, main R and D axis, international cooperation)

Use of nuclear and nuclear-related analytical techniques in studies of trace and minor elements in air pollution

International Nuclear Information System (INIS)

Smodis, Borut; Stropnik, Boris

1994-01-01

Among nuclear and nuclear-related analytical techniques, neutron activation and X-ray fluorescence analysis are particularly useful for environmental studies owing to their non-destructive character and multi-element capability. In this work, procedures for k o -standardized instrumental neutron activation analysis (INAA) and energy-dispersive X-ray fluorescence (EDXRF) spectrometry for trace and minor elements in air pollution studies were investigated. The methods applied were validated by the analysis of suitable reference materials. Using INAA, 20 experimentally obtained elemental values out of 21 certified and all 29 experimentally obtained values compared with 'consensus' values (for the elements where no certified numbers are available) in two SRMs were statistically indistinguishable. Also, the contents of 28 elements in candidate NIST SRM 1573a Tomato Leaves are reported. The EDXRF results were statistically indistinguishable from certified values for eight out of nine elements in NIST SRM 3087. The detection limit for this method is around at 0.1 μg cm -2 per element, so in BCR CRM No. 128, which is intended for ambient air pollution data, only Fe and Zn out of 14 elements reported in the certificate were detected with acceptable precision (i.e., 10%) owing to the very low air particulate matter loading, lying in the region of only 250 μg cm -2 . (Author)

From transuranic to superheavy elements a story of dispute and creation

CERN Document Server

Kragh, Helge

2018-01-01

The story of superheavy elements  - those at the very end of the periodic table  - is not well known outside the community of heavy-ion physicists and nuclear chemists. But it is a most interesting story which deserves to be known also to historians, philosophers, and sociologists of science and indeed to the general public. This is what the present work aims at. It tells the story or rather parts of the story, of how physicists and chemists created elements heavier than uranium or searched for them in nature. And it does so with an emphasis on the frequent discovery and naming disputes concerning the synthesis of very heavy elements. Moreover, it calls attention to the criteria which scientists have adopted for what it means to have discovered a new element. In this branch of modern science it may be more appropriate to speak of creation instead of discovery. The work will be of interest to scientists as well as to scholars studying modern science from a meta-perspective.

Heavy-ion collisions and the nuclear equation of state

International Nuclear Information System (INIS)

Keane, D.

1993-01-01

The overall goal of this project is to study nucleus-nucleus collisions experimentally at intermediate and relativistic energies, with emphasis on measurement and interpretation of correlation effects that provide insight into the nuclear phase diagram and the nuclear equation of state. During the course of this reporting period, the PI returned to Kent from a 15-month leave at Lawrence Berkeley Lab, which had been devoted 100% to work on this research project. The EOS Time Projection Chamber at LBL's Bevalac accelerator has continued to be the major focus of research for all of the supported personnel; about a year ago, this detector successfully took data in production mode for the first time, and accumulated in excess of 1000 hours of beam time before the termination of the Bevalac in February 1993. Reduction and analysis of these data is currently our first priority. Effort has also been devoted to the STAR detector at the Relativistic Heavy Ion Collider, in the form of contributions to the Conceptual Design Report, work on HV control hardware and software for use with the STAR Time Projection Chamber, and tracking software development

Trace elements and heavy metals in the Grand Bay National Estuarine Reserve in the northern Gulf of Mexico

Science.gov (United States)

The Grand Bay National Estuarine Research Reserve has the highest biotic diversity of habitats and offer a reserve of food resources and commercially significant species. Rapid human civilization has led to accumulation of heavy metals and trace elements in estuaries. The Grand Bay National Estuarin...

Systematical calculations on the ground state properties of heavy and superheavy nuclei

International Nuclear Information System (INIS)

Ren, Z.Z.; Center of Theoretical Nuclear Physics, Lanzhou; Mao, Y.C.; Zhi, Q.J.; Xu, C.; Dong, T.K.

2007-01-01

The synthesis of superheavy elements is now a hot topic in nuclear physics. Alpha-decay and spontaneous fission are two main decay modes in heavy and superheavy regions. Theoretical studies on alpha radioactivity and spontaneous fission can provide useful information for experiments. We investigate the alpha-decay and spontaneous fission of heavy and superheavy nuclei with different models. This includes the alpha-decay energies, alpha decay half-lives, and half-lives of spontaneous fission. The theoretical alpha-decay half-lives are in good agreement with experimental ones. The calculated half-lives of spontaneous fission are in reasonable agreement with present data. The properties of unknown nuclei are predicted. (author)

Indian heavy water programme - challenges and opportunities

International Nuclear Information System (INIS)

Aruldoss Kanthiah, W.S.

2010-01-01

Discovery of fission of uranium in 1939 opened up hitherto unknown possibilities for utilising the fission energy for use of mankind, mainly for the production of and electrical energy. It was realised that this nuclear energy could be an ideal substitute for the fast depleting fossil fuels which would one day get exhausted. Two main concepts of nuclear power reactor got evolved, one enriched uranium fuelled, ordinary water moderated reactor and another natural uranium fuelled heavy water moderated reactor. The concentration of uranium 235 U needed for ordinary water moderated reactors is 3% but the naturally occurring uranium in India contains only 0.7% of 235 U. The reactors utilising natural uranium as fuel require Heavy Water as moderator. The processing of uranium ore to achieve from 0.7% to 3% is highly complex. Recognising the fact that India has limited uranium resources but rich thorium resources, Dr. Bhabha formulated a three stage nuclear power generation programme for our country. The first generation reactors can use natural uranium as fuel with heavy water as moderator. Since the technology to generate such large scale heavy water to match the urgent need for nuclear power generation was not indigenously available, the technology available with Canada and France was utilised for installation of first generation heavy water plants in India. However, the peaceful nuclear experiment conducted by India in 1974 caused resentment among the countries that supplied Heavy Water technology to India and they stopped all technological help and assistance in nuclear field. Thereafter, it was the story of India going alone in heavy water production. That made India meets successfully all challenges on the way to installation, commissioning and sustained operation of all plants. Today we have six operating Heavy Water plants, spread all over the country. We have reached a stage, a change from a situation of crunch to a level of not only self sufficiency but to a

Study of rare earth elements, uranium and thorium migration in rocks from Espinharas uranium deposit, Paraiba - Brazil

International Nuclear Information System (INIS)

Conceicao, Cirilo C.S.

2009-01-01

The determination of rare earth elements as natural analogue in patterns geologic has grown as a tool for predicting the long-term safety of nuclear disposal in geological formation. Migration of natural radionuclides is one of the most serious problems in the waste deposit from nuclear fuel cycle. Rare earth elements show the same kinetic behavior in rocks as natural radionuclides. This similar property of the analogues allows perform studies and models on the subject of radionuclides migration. The aim of this study was to determine the distribution of rare earth elements in rocks located at Espinharas - Paraiba - Brazil, uranium deposit. In this work are presented the results from the study above the distribution of rare earth elements in function of the degree of mineralized rocks, composition and the conditions of radioactive equilibrium of the uranium and thorium in some fractures on the rocks from radioactive occurrence of Espinharas-Brazil. The results show that there is a correlation of heavy rare earth elements, uranium and Thorium concentrations to oxidation factor of the rocks. However this correlation was not observed for light rare earth elements. It means that heavy rare earth elements follow the natural radionuclides in oxidation process of rocks. The samples were analyzed by ICP-MS, alpha and gamma spectrometry, X-ray diffraction and fluorimetry. (author)

Device for preventing spontaneous repositioning of a control element of a nuclear reactor

International Nuclear Information System (INIS)

Maslenok, B.A.; Chegaj, A.S.; Slobin, W.G.; Mednickij, W.G.; Genkin, L.I.; Petritschenko, N.F.; Mitrofanow, B.I.

1976-01-01

The invention concerns the control element of a nuclear reactor. The vertical connecting rod is to be prevented from spontaneous repositioning if the pressurized housing which encloses the control element becomes leaky. It is proposed to provide spheres as wedging elements locking the connecting rod, but also allowing easy loosening. (UWI) [de

Present status of research activities conducted by research group for heavy elements microbiology in JAERI

International Nuclear Information System (INIS)

Ohnuki, Toshihiko; Ozaki, Takuo; Yoshida, Takahiro

2004-01-01

It has been recognized that microbial transformations of radionuclides and toxic metals could be significant in the environment, but there is a paucity of information on the mechanisms of biotransformation of radionuclides by the microorganisms. An understanding at the fundamental level the mechanisms of mobilization, immobilization and bioavailability of radioactive elements in particular the actinides is important from the standpoint of mobility of actinides in the environment, disposal of radioactive wastes in deep geological formation, remediation of contaminated soils and materials, and development of strategies for the long-term stewardship of the contaminated sites. The microbiology research group in Japan Atomic Energy Research Institute (JAERI) is conducting basic scientific research on microbial interactions with actinides. Fundamental research on microbial transformations of actinides include elucidation of the mechanisms of dissolution and precipitation of various chemical forms such as ionic, oxides, organic and inorganic complexes of actinides by aerobic or anaerobic microorganisms under relevant microbial process conditions. State-of-the-art analytical techniques are used to determine the interaction of actinides with microorganisms at the molecular level to understand the structure function relationship. These techniques include time-resolved laser fluorescence spectroscopy (TRLFS) to determine the coordination number, oxidation states and the nearest neighbor by X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) at the Synchrotron Light Source, identification of functional groups by nuclear magnetic resonance (NMR), determination of chemical forms by transmission electron microscopy (TEM), and genomic (DNA) manipulation by molecular techniques. We here report the present status of our research activities on accumulation of lanthanides(III) by microorganisms, application of micro-particle induced X

2007 Nuclear Data Review

International Nuclear Information System (INIS)

Holden, N.E.

2008-01-01

The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature are presented. The status of new chemical elements is examined. Data on revised values for the isotopic composition of the elements are reviewed and recommended values are presented. Half-lives of very long-lived nuclides are presented, including double beta decay, double electron capture, long-lived alpha decay and long-lived beta decay. Data from new measurements on the very heavy elements (trans-meitnerium elements) are discussed and tabulated. The first observation of the radioactive decay mode of the free neutron is discussed. New measurements that have expanded the neutron drip line for magnesium and aluminum are discussed. Data on recent neutron cross-section and resonance integral measurements are also discussed

[Determination of Heavy Metal Elements in Diatomite Filter Aid by Inductively Coupled Plasma Mass Spectrometry].

Science.gov (United States)

Nie, Xi-du; Fu, Liang

2015-11-01

This study established a method for determining Be, Cr, Ni, As, Cd, Sb, Sn, Tl, Hg and Pb, total 10 heavy metals in diatomite filter aid. The diatomite filter aid was digested by using the mixture acid of HNO₃ + HF+ H₃PO₄ in microwave system, 10 heavy metals elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). The interferences of mass spectrometry caused by the high silicon substrate were optimized, first the equipment parameters and isotopes of test metals were selected to eliminate these interferences, the methane was selected as reactant gas, and the mass spectral interferences were eliminated by dynamic reaction cell (DRC). Li, Sc, Y, In and Bi were selected as the internal standard elements to correct the interferences caused by matrix and the drift of sensitivity. The results show that the detection limits for analyte is in the range of 3.29-15.68 ng · L⁻¹, relative standard deviations (RSD) is less than 4.62%, and the recovery is in the range of 90.71%-107.22%. The current method has some advantages such as, high sensitivity, accurate, and precision, which can be used in diatomite filter aid quality control and safety estimations.

Incorporation of transuranic elements in titanate nuclear waste ceramics

International Nuclear Information System (INIS)

Matzke, H.J.; Ray, I.L.F.; Theile, H.; Trisoglio, C.; Walker, C.T.; White, T.J.

1990-01-01

The incorporation of actinide elements and their rare-earth element analogues in titanate nuclear waste forms in reviewed. New partitioning data are presented for three waste forms containing Purex waste simulant in combination with either NpO 2 , PuO 2 , or Am 2 O 3 . The greater proportion of transuranics partition between perovskite and zirconolite, while some americium may enter loveringite. Autoradiography revealed clusters of plutonium atoms which have been interpreted as unreacted dioxide or sesquioxide. It is concluded that the solid-state behavior of transuranic elements in titanate waste forms is poorly understood, certainly not well enough to tailor a ceramic for the incorporation of waste from reprocessing of fast breeder reactor fuel in which transuranic species are more abundant than in Purex waste

Department of Nuclear Reactions: Overview

International Nuclear Information System (INIS)

Rusek, K.

2000-01-01

Full text: During last year the physicists of the Department of Nuclear Reactions were involved in many experiments and projects: -Low energy nuclear reactions: For the first time a heavy ion beam from the Warsaw Cyclotron C-200 was used to investigate elastic and inelastic scattering of 12 C ions from 12 C target. The experiment is a part of a long range programme devoted to study the energy dependence of the nucleus-nucleus interactions. -Multifragmentation of relativistic heavy ions: Multifragmentation reactions induced by 12 C on different heavy targets and at different energies were studied in experiments performed at Gesellschaft fuer Schwerionenforschung by the ALADIN Collaboration. These asymmetric systems were investigated in order to study the interplay between preequilibrium and equilibrium phenomena in the nuclear liquid - gas phase transition. -The structure of nucleons: A novel, two-structure description of the Roper resonance was proposed on the basis of the α-p scattering data reanalysed by means of a T-matrix formalism. -Atomic physics: Emission of the X-rays by fast heavy ions (S, Ti, Fe) as they traverse the matter (thin carbon or other light element foil) was investigated in a series of experiments performed at University of Erlangen. It was demonstrated, that the characteristic K α X-rays emitted by a heavy ion can serve as a tool for Z-value control of the ion. -Material research: Semiconductor heterostructures were investigated by means of Rutherford Back Scattering and Channeling methods using the 2 MeV α particles from the Van de Graaff accelerator ''Lech'' at the Department. The following reports present the results and major successes which were achieved in 1999. (author)

Quasifission Dynamics in the Formation of Superheavy Elements

Directory of Open Access Journals (Sweden)

Hinde D.J.

2017-01-01

Full Text Available Superheavy elements are created through the fusion of two heavy nuclei. The large Coulomb energy that makes superheavy elements unstable also makes fusion forming a compact compound nucleus very unlikely. Instead, after sticking together for a short time, the two nuclei usually come apart, in a process called quasifission. Mass-angle distributions give the most direct information on the characteristics and time scales of quasifission. A systematic study of carefully chosen mass-angle distributions has provided information on the global trends of quasifission. Large deviations from these systematics at beam energies near the capture barrier reveal the major role played by the nuclear structure of the two colliding nuclei in determining the reaction outcome, and thus implicitly in hindering or favouring superheavy element synthesis.

Labile rhizosphere soil solution fraction for prediction of bioavailability of heavy metals and rare earth elements to plants.

Science.gov (United States)

Shan, Xiao-Quan; Wang, Zhongwen; Wang, Weisheng; Zhang, Shuzhen; Wen, Bei

2003-02-01

A labile rhizosphere soil solution fraction has been recommended to predict the bioavailability of heavy metals and rare earth elements to plants. This method used moist rhizosphere soil in combination with a mixture of 0.01 mol L(-1) of low-molecular-weight organic acids (LMWOAs) as extractant. The extracted soil solutions were fractionated into two colloidal fractions of soil solution fraction, F(lrss). For the soil solutions extracted with a mixture of LMWOAs the concentrations of heavy metals and rare earth elements in F(2) and F(3) were quite similar. However, the mean concentrations of Cr, Ni, Zn, Cu, Pb, Cd, La, Ce, Pr, and Nd in F(lrss) accounted for 79.9%, 91.3%, 90.8%, 60.1%, 77.5%, 75.3%, 81.2%, 77.2%, 80.3%, and 79.5%, respectively, of their concentrations in F(2). In contrast, there were no differences in the extractable metal concentrations between the three fractions while the first step of the method recommended by the European Community of Reference (BCR), where 0.1 mol L(-1) acetic acid was used as an extractant. The single correlation analysis was made between metal concentrations in the different fractions of soil solutions and their concentrations in wheat. If the first step of BCR method was used there was no good correlation between heavy metals in soil pools and that in wheat shoots and roots. When LMWAOs were used a good correlation was obtained between the concentrations of heavy metals in soil pools and that in wheat roots, which followed a general order of r(1 kD, LMWOAs) >r(0.2 microm, LMWOAs) approximately r(0.45 microm, LMWOAs). In the case of rare earth elements the good correlation was obtained for both the wheat roots and shoots. Generally, the correlation coefficients obtained by LMWAOs were better than that obtained by the first step of BCR method. Therefore, LMWAOs and F(lrss) were strongly recommended to predict the bioavailability of metals in soil pools to plants.

Radiation damage in heavy irradiated aluminum nitride

Energy Technology Data Exchange (ETDEWEB)

Atobe, Kozo; Honda, Makoto; Fukuoka, Noboru [Naruto Univ. of education, Tokushima (Japan); Okada, Moritami; Nakagawa, Masuo

1996-04-01

AlN, one of candidate for ceramic materials used in nuclear fusion reactor, was irradiated by fast and thermal neutrons. The high concentration of irradiated defects and the nuclear transformation elements were detected by electron spin resonance (ESR) and x-ray photoelectron spectroscopy (XPS) method. The exposure of fast neutron and thermal neutron were 1.2x10{sup 20}n/cm{sup 2} and 1.2x10{sup 21}n/cm{sup 2}, respectively. The spreads of ESR spectra of ultra hyperfine structure depending on interaction between {sup 27}Al nuclear spin and electron trapped in tetrahedron consisted of Al atoms was found in the spectra of heavy irradiated AlN. F type defects was estimated 10{sup 19}n/cm{sup 3}. Photoelectrons from 2s and 2p in {sup 28}Si which produced in process of {beta}-decay of {sup 27}Al(n,{gamma}){sup 28}Al were observed in XPS spectra of irradiated samples. (S.Y.)

Radiation damage in heavy irradiated aluminum nitride

International Nuclear Information System (INIS)

Atobe, Kozo; Honda, Makoto; Fukuoka, Noboru; Okada, Moritami; Nakagawa, Masuo.

1996-01-01

AlN, one of candidate for ceramic materials used in nuclear fusion reactor, was irradiated by fast and thermal neutrons. The high concentration of irradiated defects and the nuclear transformation elements were detected by electron spin resonance (ESR) and x-ray photoelectron spectroscopy (XPS) method. The exposure of fast neutron and thermal neutron were 1.2x10 20 n/cm 2 and 1.2x10 21 n/cm 2 , respectively. The spreads of ESR spectra of ultra hyperfine structure depending on interaction between 27 Al nuclear spin and electron trapped in tetrahedron consisted of Al atoms was found in the spectra of heavy irradiated AlN. F type defects was estimated 10 19 n/cm 3 . Photoelectrons from 2s and 2p in 28 Si which produced in process of β-decay of 27 Al(n,γ) 28 Al were observed in XPS spectra of irradiated samples. (S.Y.)

Trace elements in land plants: concentration ranges and accumulators of rare earths, Ba, Ra, Mn, Fe, Co and heavy halogens

International Nuclear Information System (INIS)

Koyama, M.; Shirakawa, M.; Takada, J.; Katayama, Y.; Matsubara, T.

1987-01-01

More than 2000 samples of land plant leaves, mostly of tree, were analyzed by neutron activation analysis in order to find out macroscopic relations between distributions of chemical elements in plants and soil characteristics. The distributions of the elements in plants were also examined from the view point of botanical taxonomy or phylogeny. New species which accumulate Co, rare earths, Ba, Ra, heavy halogens and some other elements were found. Capability or potentiality for accumulating elements could be related to higher ranks of taxonomy, that is, genus or family. The nature of soil is also found to have profound effects on the extent of accumulation of elements in plants. (author)

From heavy nuclei to super-heavy nuclei; Des noyaux lourds aux super-lourds

Energy Technology Data Exchange (ETDEWEB)

Theisen, Ch

2003-01-01

The existence of super-heavy nuclei has been predicted nearly fifty years ago. Due to the strong coulomb repulsion, the stabilisation of these nuclei is possible only through shell effects. The reasons for this fragile stability, as well as the theoretical predictions concerning the position of the island of stability are presented in the first part of this lecture. In the second part, experiments and experimental techniques which have been used to synthesize or search for super-heavy elements are described. Spectroscopic studies performed in very heavy elements are presented in the following section. We close this lecture with techniques that are currently being developed in order to reach the superheavy island and to study the structure of very-heavy nuclei. (author)

Seismic analysis of the APR1400 nuclear reactor system using a verified beam element model

Energy Technology Data Exchange (ETDEWEB)

Park, Jong-beom [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Park, No-Cheol, E-mail: pnch@yonsei.ac.kr [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Lee, Sang-Jeong; Park, Young-Pil [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Choi, Youngin [Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon 34142 (Korea, Republic of)

2017-03-15

Highlights: • A simplified beam element model is constructed based on the real dynamic characteristics of the APR1400. • Time history analysis is performed to calculate the seismic responses of the structures. • Large deformations can be observed at the in-phase mode of reactor vessel and core support barrel. - Abstract: Structural integrity is the first priority in the design of nuclear reactor internal structures. In particular, nuclear reactor internals should be designed to endure external forces, such as those due to earthquakes. Many researchers have performed finite element analyses to meet these design requirements. Generally, a seismic analysis model should reflect the dynamic characteristics of the target system. However, seismic analysis based on the finite element method requires long computation times as well as huge storage space. In this research, a beam element model was developed and confirmed based on the real dynamic characteristics of an advanced pressurized water nuclear reactor 1400 (APR1400) system. That verification process enhances the accuracy of the finite element analysis using the beam elements, remarkably. Also, the beam element model reduces seismic analysis costs. Therefore, the beam element model was used to perform the seismic analysis. Then, the safety of the APR1400 was assessed based on a seismic analysis of the time history responses of its structures. Thus, efficient, accurate seismic analysis was demonstrated using the proposed beam element model.

Seismic analysis of the APR1400 nuclear reactor system using a verified beam element model

International Nuclear Information System (INIS)

Park, Jong-beom; Park, No-Cheol; Lee, Sang-Jeong; Park, Young-Pil; Choi, Youngin

2017-01-01

Highlights: • A simplified beam element model is constructed based on the real dynamic characteristics of the APR1400. • Time history analysis is performed to calculate the seismic responses of the structures. • Large deformations can be observed at the in-phase mode of reactor vessel and core support barrel. - Abstract: Structural integrity is the first priority in the design of nuclear reactor internal structures. In particular, nuclear reactor internals should be designed to endure external forces, such as those due to earthquakes. Many researchers have performed finite element analyses to meet these design requirements. Generally, a seismic analysis model should reflect the dynamic characteristics of the target system. However, seismic analysis based on the finite element method requires long computation times as well as huge storage space. In this research, a beam element model was developed and confirmed based on the real dynamic characteristics of an advanced pressurized water nuclear reactor 1400 (APR1400) system. That verification process enhances the accuracy of the finite element analysis using the beam elements, remarkably. Also, the beam element model reduces seismic analysis costs. Therefore, the beam element model was used to perform the seismic analysis. Then, the safety of the APR1400 was assessed based on a seismic analysis of the time history responses of its structures. Thus, efficient, accurate seismic analysis was demonstrated using the proposed beam element model.

Element Distribution and Multiplicity of Heavy Fragments

CERN Multimedia

2002-01-01

This experiment will measure the energy and angular distribution of heavy fragments produced in the reactions of |1|2C on several targets between |2|7Al and |2|3|8U at 86~MeV/u. The systematic investigation of a highly excited interaction region (fireball) by means of a clean N and Z identification of heavy tar fragments, may result in a better understanding of temperature concept and of the degree of equilibration of the local interaction region with respect to the total system. For this investigation a large-area position sensitive ionization chamber of 50~msr solid angle in conjunction with a time-of-flight telescope consisting of parallel-plate detectors will be used. \\\\ \\\\ In order to get information on the transverse momentum transfer and the inelasticity of the collision, the energy of the PROJECTILE-FRAGMENTS will be measured at forward angles with a plastic scintillator hodoscope. In addition to this inclusive measurement correlations between heavy fragments will be investigated by means of three pos...

Physical and chemical investigation of water and sediment of the Keban Dam Lake, Turkey. Part 2. Distribution of radioactivity, heavy metals and major elements

International Nuclear Information System (INIS)

Kulahci, F.; Dogru, M.

2006-01-01

Thirtynine surface water and 20 deep sediment samples were taken in different locations in Keban Dam Lake (Elazig, Turkey) to identify major sources and assess major elements, heavy metals, 137 Cs, 90 Sr, total alpha- and, total beta-distribution in 2003 and 2004 in four seasons each year. As a preliminary study heavy metal (Zn, Fe, Mn, Ni, Cu, Cr, and Co), major element (Mg, Ca, Na, K) and radioactivity concentrations of 137 Cs, 90 Sr, total-α and total-β in the surface water and deep sediments were determined. (author)

Six key elements' analysis of FAC effective management in nuclear power plant

International Nuclear Information System (INIS)

Zhong Zhaojiang; Chen Hanming

2010-01-01

Corporate Commitment, Analysis, Operating Experience, Inspection, Training and Engineering Judgment, Long-Term Strategy are the six key elements of FAC effective management in nuclear power plant. Corporate commitment is the economy base of FAC management and ensure of management system, Analysis is the method of FAC's optimization and consummation, Operating experience is the reference and complementarity of FAC, Inspection is the base of accumulating FAC data, Training and engineering judgment is the technical complementarity and deepening, Long-term strategy is successful key of FAC management. Six key elements supplement each other, and make up of a full system of FAC effective management. For present FAC management in our national nuclear power plant, six key elements are the core and bring out the best in each other to found the FAC effective management system and prevent great FAC occurrence. (authors)

Experience in the development of metal uranium-base nuclear fuel for heavy-water gas-cooled reactors

International Nuclear Information System (INIS)

Ashikhmin, V.P.; Vorob'ev, M.A.; Gusarov, M.S.; Davidenko, A.S.; Zelenskij, V.F.; Ivanov, V.E.; Krasnorutskij, V.S.; Petel'guzov, I.A.; Stukalov, A.I.

1978-01-01

Investigations were carried out to solve the problem of making the development of radiation-resistant uranium fuel for power reactors including the heavy-water gas-cooled KS-150 reactor. Factors are considered that limit the lifetime of uranium fuel elements, and the ways of suppressing them are discussed. Possible reasons of the insufficient radiation resistance of uranium rod fuel element and the progress attained are analyzed. Some general problems on the fuel manufacture processes are discussed. The main results are presented on the operation of the developed fuel in research reactor loops and the commercial heavy-water KS-150 reactor. The results confirm an exceptionally high radiation resistance of fuel to burn-ups of 1.5-2%. The successful solution of a large number of problems associated with the development of metal uranium fuel provides for new possibilities of using metal uranium in power reactors

Experimental study of water flow in nuclear fuel elements

International Nuclear Information System (INIS)

Rodrigues, Lorena Escriche; Rezende, Hugo Cesar; Mattos, Joao Roberto Loureiro de; Barros Filho, Jose Afonso; Santos, Andre Augusto Campagnole dos

2013-01-01

This work aims to develop an experimental methodology for investigating the water flow through rod bundles after spacer grids of nuclear fuel elements of PWR type reactors. Speed profiles, with the device LDV (Laser Doppler Velocimetry), and the pressure drop between two sockets located before and after the spacer grid, using pressure transducers were measured