Behaviour of Selenium in Boom Clay

Total Page:16

File Type:pdf, Size:1020Kb

Behaviour of Selenium in Boom Clay EXTERNAL REPORT SCK•CEN-ER-120 10/PDC/P-9 Behaviour of Selenium in Boom Clay Pierre De Cannière1, André Maes2, Steve Williams3, Christophe Bruggeman2, Thomas Beauwens1, Norbert Maes1, and Mark Cowper3 1 SCK•CEN 2 KULeuven 3 AEA Technology SCK•CEN ref: CO 90 01 1467.01 1467 RP.W&D.037 NIROND ref: CCHO2004/00/00 DS251-A44/2.1 May, 2010 SCK•CEN RDD Boeretang 200 BE-2400 Mol Belgium EXTERNAL REPORT OF THE BELGIAN NUCLEAR RESEARCH CENTRE SCK•CEN-ER-120 10/PDC/P-9 Behaviour of Selenium in Boom Clay Pierre De Cannière1, André Maes2, Steve Williams3, Christophe Bruggeman2, Thomas Beauwens1, Norbert Maes1, and Mark Cowper3 1 SCK•CEN 2 KULeuven 3 AEA Technology SCK•CEN ref: CO 90 01 1467.01 1467 RP.W&D.037 NIROND ref: CCHO2004/00/00 DS251- A44/2.1 May, 2010 Status: Unclassified ISSN 1782-2335 SCK•CEN Boeretang 200 BE-2400 Mol Belgium This report can be cited as follows: De Cannière P., Maes A., Williams S., Bruggeman C., Beauwens T., Maes N., and Cowper M. (2010) Behaviour of selenium in Boom Clay. Work performed under contract: SCK•CEN ref: CO 90 01 1467.01 1467 RP.W&D.037 – NIROND ref: CCHO2004/00/00 DS251-A44/2.1. External Report of the Belgian Nuclear Research Centre, SCK•CEN-ER-120. May 2010. PDF file available at: http://publications.sckcen.be/dspace/ http://publications.sckcen.be/dspace/simple-search © SCK•CEN Studiecentrum voor Kernenergie Centre d’étude de l’énergie Nucléaire Boeretang 200 BE-2400 Mol Belgium Phone +32 14 33 21 11 Fax +32 14 31 50 21 http://www.sckcen.be Contact: Knowledge Centre [email protected] RESTRICTED All property rights and copyright are reserved. Any communication or reproduction of this document, and any communication or use of its content without explicit authorization is prohibited. Any infringement to this rule is illegal and entitles to claim damages from the infringer, without prejudice to any other right in case of granting a patent or registration in the field of intellectual property. SCK•CEN, Studiecentrum voor Kernenergie/Centre d'Etude de l'Energie Nucléaire Stichting van Openbaar Nut – Fondation d'Utilité Publique - Foundation of Public Utility Registered Office: Avenue Herrmann Debroux 40 – BE-1160 BRUSSEL Operational Office: Boeretang 200 – BE-2400 MOL 5/328 6/328 Table of Contents Executive Summary .................................................................................................................................................11 Foreword ............................................................................................................................................................11 Summary ............................................................................................................................................................11 Redox disequilibrium..............................................................................................................................12 79 Unknown initial speciation of Se in the source term............................................................................13 79 Migration parameters selected for Se...................................................................................................13 Abstract.....................................................................................................................................................................17 1. Introduction......................................................................................................................................................21 1.1. Background.............................................................................................................................................21 1.2. Objective.................................................................................................................................................22 1.3. Main uncertainties and research strategy ................................................................................................22 1.3.1 Complexity and uncertainties affecting the experiments with selenium ..................................23 1.3.2 Objectives and research strategy ..............................................................................................24 2. Thermodynamic calculations – AEAT ...........................................................................................................29 2.1. Overview.................................................................................................................................................29 2.2. Applied geochemical codes and reference database – AEAT.................................................................29 2.3. In situ Boom Clay conditions – AEAT...................................................................................................29 2.4. Expected speciation of selenium under Boom Clay conditions – AEAT................................................30 2.5. Calculated thermodynamical solubility of selenium under Boom Clay conditions – AEAT..................32 3. Geochemical behaviour of selenium in Boom Clay .......................................................................................37 3.1. Introduction.............................................................................................................................................37 3.2. Sorption of selenium on Boom Clay and its components .......................................................................37 3.3. Kinetics of reduction of selenite .............................................................................................................41 3.4. Solubility of selenium compounds under reducing conditions ...............................................................42 3.5. Association of selenium with Boom Clay organic matter.......................................................................43 3.6. Conclusions.............................................................................................................................................45 4. Determination of migration parameters of selenium in Boom Clay............................................................49 4.1. Introduction.............................................................................................................................................49 4.2. Experimental...........................................................................................................................................50 4.3. Results.....................................................................................................................................................51 4.4. Discussion...............................................................................................................................................54 4.4.1 Pore diffusion coefficient (Dp) .................................................................................................56 4.4.2 Porosity (η) ..............................................................................................................................56 4.4.3 Sorption – retardation (R) ........................................................................................................57 4.5. Conclusion ..............................................................................................................................................58 4.5.1 Summary of the migration parameters for 79Se in Boom Clay.................................................59 5. Summary and conclusions...............................................................................................................................63 5.1. Overview.................................................................................................................................................63 5.2. Key uncertainties and abstraction for performance assessment..............................................................64 5.3. Summary of the transport parameters for the selenium species considered............................................68 7/328 5.4. Recommendations and future works.......................................................................................................71 6. Acknowledgments ............................................................................................................................................75 7. References.........................................................................................................................................................79 APPENDICES..........................................................................................................................................................149 A1 General information on selenium ...................................................................................................................153 A1.1 Overview.................................................................................................................................................153 A1.2 Inventory and isotopic composition........................................................................................................153 A1.3 Uncertainties related to the value of selenium-79 half-life and recent changes......................................154 79 75 A1.4 Nuclear decay mode of Se and Se......................................................................................................157 A1.5 Selenium inorganic and organic chemistry .............................................................................................157
Recommended publications
  • A 1 Case-PR/ }*Rciofft.;Is Report
    .A 1 case-PR/ }*rciofft.;is Report (a) This eruption site on Mauna Loa Volcano was the main source of the voluminous lavas that flowed two- thirds of the distance to the town of Hilo (20 km). In the interior of the lava fountains, the white-orange color indicates maximum temperatures of about 1120°C; deeper orange in both the fountains and flows reflects decreasing temperatures (<1100°C) at edges and the surface. (b) High winds swept the exposed ridges, and the filter cannister was changed in the shelter of a p^hoehoc (lava) ridge to protect the sample from gas contamination. (c) Because of the high temperatures and acid gases, special clothing and equipment was necessary to protect the eyes. nose, lungs, and skin. Safety features included military flight suits of nonflammable fabric, fuil-face respirators that are equipped with dual acidic gas filters (purple attachments), hard hats, heavy, thick-soled boots, and protective gloves. We used portable radios to keep in touch with the Hawaii Volcano Observatory, where the area's seismic activity was monitored continuously. (d) Spatter activity in the Pu'u O Vent during the January 1984 eruption of Kilauea Volcano. Magma visible in the circular conduit oscillated in a piston-like fashion; spatter was ejected to heights of 1 to 10 m. During this activity, we sampled gases continuously for 5 hours at the west edge. Cover photo: This aerial view of Kilauea Volcano was taken in April 1984 during overflights to collect gas samples from the plume. The bluish portion of the gas plume contained a far higher density of fine-grained scoria (ash).
    [Show full text]
  • 9.2.3.7 Retention Parameters in Column Chromatography
    9.2.3.7 Retention Parameters in Column Chromatography Retention parameters may be measured in terms of chart distances or times, as well as mobile phase volumes; e.g., tR' (time) is analogous to VR' (volume). If recorder speed is constant, the chart distances are directly proportional to the times; similarly if the flow rate is constant, the volumes are directly proportional to the times. Note: In gas chromatography, or in any chromatography where the mobile phase expands in the column, VM, VR and VR' represent volumes under column outlet pressure. If Fc, the carrier gas flow rate at the column outlet and corrected to column temperature (see Flow Rate), is used in calculating the retention volumes from the retention time values, these correspond to volumes at column temperatures. The various conditions under which retention volumes (times) are expressed are indicated by superscripts: thus, a prime ('; as in VR') refers to correction for the hold-up volume (and time) while a circle (º; as in VRº) refers to correction for mobile-phase compression. In the case of the net retention volume (time) both corrections should be applied: however, in order not to confuse the symbol by the use of a double superscript, a new symbol (VN, tN) is used for the net retention volume (time). Hold-up Volume (Time) (VM, tM ) The volume of the mobile phase (or the corresponding time) required to elute a component the concentration of which in the stationary phase is negligible compared to that in the mobile phase. In other words, this component is not retained at all by the stationary phase.
    [Show full text]
  • Calculations of \(N,2N\) Reaction Cross Sections for 74,76,78,80,82Se up to 20
    128 EPJ Web of Conferences , 01001 (2016) DOI: 10.1051/epjconf/201612801001 TESNAT 2016 Halide Şahan1,a, Muhittin Şahan1, Eyyup Tel1 1Osmaniye Korkut Ata University, Faculty of Arts and Science, Department of Physics, Osmaniye, Turkey In the present work, the excitation functions of (n,2n) reactions for five isotopes of selenium (74,76,78,80,82Se) are calculated using ALICE/ASH, EMPIRE-3.2.2, PCROSS, and TALYS 1.6 computer codes based on statistical model up to 20 MeV. The theoretical calculations provide information of the (n,2n) excitation functions with the increasing target neutron number of selenium element. The calculated cross-sections were compared with experimental data from EXFOR and also with the cross- sections estimated with semi empirical formula developed by Tet et al. (2008) [18]. Results show a reasonably good agreement between the calculations and the experimental data from literature. ! " by Tel et al. [13]. These formulas have been given as follows; The theoretical calculation models are necessary to ⎪⎧7.15[]1− 2.45e−31.620(N −Z ) / A for even A⎪⎫ provide the estimation of the particle–induced reaction σ = (1) ln n,2n ⎨ ⎬ cross sections due to the experimental difficulty [1,2]. In ⎩⎪ 7.65[]1−1.59e−23.06(N −Z ) / A for odd A⎭⎪ past years the cross section of selenium isotopes (74,76,78,80,82,84Se) around 14-15 MeV have been measured For (n,2n) reaction cross sections of 74Se(n,2n)73Se, by many researches such as Hille and Münzer [3]; 76Se(n,2n)75Se, 78Se(n,2n)77Se, 80Se(n,2n)79Se and Minetti and Pasquarelli [4]; Casanova and Sanchez [5]; 82Se(n,2n)81Se at 14-15 MeV, the calculated cross 74,76,78,80,82 Hoang et al.
    [Show full text]
  • AN43285 – Accurate Determination of Arsenic and Selenium in Environmental Samples Using Triple Quadrupole ICP-MS
    Certified for Thermo Scientific™ iCAP™ TQe ICP-MS APPLICATION NOTE 43285 Accurate determination of arsenic and selenium in environmental samples using triple quadrupole ICP-MS Authors: Marcus Manecki1, Simon Lofthouse2, Philipp Boening3 and Shona McSheehy Ducos1; 1Thermo Fisher Scientific, Bremen, Germany; 2Thermo Fisher Scientific, Hemel Hempstead, UK; 3Institute of Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany Keywords: Arsenic, interference removal, Selenium for example is an essential element that is REE, rock, selenium, soil, sediment necessary for normal thyroid function and due to its antioxidant properties, is associated with several health Goal benefits. Diseases associated with selenium deficiency To demonstrate the accurate determination of arsenic such as Keshan disease and symptoms of hypothyroidism, and selenium in sediments and rocks that contain elevated are most commonly found in areas where levels of levels of rare earth elements using triple quadrupole selenium in soil are particularly low. Supplementation as a ICP-MS. remedy is common practice and is not isolated to humans. Understanding where soil selenium deficiencies occur for Introduction example supports the correct supplementation of cattle Due to the impact arsenic and selenium can have in the grazing in those areas to prevent white muscle disease environment at low levels, as a toxin or essential nutrient (a cattle specific selenium deficiency disease). respectively, it is important to be able to quantify them accurately. Arsenic on the other hand, in its inorganic forms Instrumentation (the most common forms found in ground water and soils) An iCAP TQ ICP-MS was used to analyse all samples.
    [Show full text]
  • Hyperfine Structure in Selenium, Palladium and Gold.* by L
    HYPERFINE STRUCTURE IN SELENIUM, PALLADIUM AND GOLD.* BY L. SIBAZ~A. (From the Dcpa,'tment of Physics, CeJ~tral College, Balzgarore.) Received September 10, 1935. Selenium (At. no. 34; At. wt. 79.2). l'oI~ purposes of classification of selenium spectra, the arc arid spark lines of seleniunl have been mostly excited in tubes of various types with con- (lensed or uncondensed electrical discharge through selenium vapour or between alumiuium poles tipped with metallic selenium. A selenium arc either in vacuum or iu an atmosphere of nitrogen has aIso been employed. Such sources however are not suited for hyperfine structure work, as the lines obtained are broad and diffuse. Moreover most of the prominent are lines of selenium lie either in the near infra-red or in the extreme ultra-violet, thus rendering their analysis by high resolving power apparatus specially difficult. Some intense spark lines of selenium 1% in the visible region; lmt under the conditions employed for their emission in discharge tubes, the broadening of the lines renders such sources unsuitable for hyperfine structure study. The apparatus used, the essential part of ~-hich is a water- cooled hollow cathode, is the same as that employed by 2Prof. Venkatesaehar and the author in their investigation on the isotopic constitution of platinum, x The selenium powcler took the place of the platinum foil in the tubular space of the cathode (P1. XV, Fig. 1). For experimental details the above paper -,,~+ he consulted. Of the seventeen lines of selenium here examined, only two are are lines and the remaining fifteen belong to the first spark spectrum of selenium.
    [Show full text]
  • Quantitative Thin-Layer Chromatography
    Quantitative Thin-Layer Chromatography A Practical Survey Bearbeitet von Bernd Spangenberg, Colin F. Poole, Christel Weins 1. Auflage 2011. Buch. xv, 388 S. Hardcover ISBN 978 3 642 10727 6 Format (B x L): 15,5 x 23,5 cm Gewicht: 839 g Weitere Fachgebiete > Chemie, Biowissenschaften, Agrarwissenschaften > Analytische Chemie > Instrumentelle Chemische Analytik, Chromatographie Zu Inhaltsverzeichnis schnell und portofrei erhältlich bei Die Online-Fachbuchhandlung beck-shop.de ist spezialisiert auf Fachbücher, insbesondere Recht, Steuern und Wirtschaft. Im Sortiment finden Sie alle Medien (Bücher, Zeitschriften, CDs, eBooks, etc.) aller Verlage. Ergänzt wird das Programm durch Services wie Neuerscheinungsdienst oder Zusammenstellungen von Büchern zu Sonderpreisen. Der Shop führt mehr als 8 Millionen Produkte. Chapter 2 Theoretical Basis of Thin Layer Chromatography (TLC) 2.1 Planar and Column Chromatography In column chromatography a defined sample amount is injected into a flowing mobile phase. The mix of sample and mobile phase then migrates through the column. If the separation conditions are arranged such that the migration rate of the sample components is different then a separation is obtained. Often a target compound (analyte) has to be separated from all other compounds present in the sample, in which case it is merely sufficient to choose conditions where the analyte migration rate is different from all other compounds. In a properly selected system, all the compounds will leave the column one after the other and then move through the detector. Their signals, therefore, are registered in sequential order as a chromatogram. Column chromatographic methods always work in sequence. When the sample is injected, chromatographic separation occurs and is measured.
    [Show full text]
  • Detection of Elements at All Three R-Process Peaks in the Metal-Poor Star HD 160617
    Published in the Astrophysical Journal A Preprint typeset using LTEX style emulateapj v. 5/2/11 DETECTION OF ELEMENTS AT ALL THREE R-PROCESS PEAKS IN THE METAL-POOR STAR HD 1606171 ,2 ,3 Ian U. Roederer4 and James E. Lawler5 Published in the Astrophysical Journal ABSTRACT We report the first detection of elements at all three r-process peaks in the metal-poor halo star HD 160617. These elements include arsenic and selenium, which have not been detected previously in halo stars, and the elements tellurium, osmium, iridium, and platinum, which have been detected previously. Absorption lines of these elements are found in archive observations made with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. We present up-to-date absolute atomic transition probabilities and complete line component patterns for these elements. Additional archival spectra of this star from several ground-based instruments allow us to derive abundances or upper limits of 45 elements in HD 160617, including 27 elements produced by neutron-capture reactions. The average abundances of the elements at the three r-process peaks are similar to the predicted solar system r-process residuals when scaled to the abundances in the rare earth element domain. This result for arsenic and selenium may be surprising in light of predictions that the production of the lightest r-process elements generally should be decoupled from the heavier r-process elements. Subject headings: atomic data — nuclear reactions, nucleosynthesis, abundances — stars: abundances — stars: individual (HD 160617) — stars: Population II 1. INTRODUCTION in greater abundance during n-capture reactions. The Understanding the origin of the elements is one of the s-process path closely follows the valley of β-stability, major challenges of modern astrophysics.
    [Show full text]
  • 1 Novel Nanomaterials and Chromatographic System for Enhanced Separation and Characterization of Biomacromolecules and Nanoparti
    Novel Nanomaterials and Chromatographic System for Enhanced Separation and Characterization of Biomacromolecules and Nanoparticles Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Yanhui Wang, M.S. Graduate Program in Chemistry The Ohio State University 2018 Dissertation Committee Dr. Susan V. Olesik, Advisor Dr. Philip Grandinetti Dr. Abraham Badu-Tawiah 1 Copyrighted by Yanhui Wang 2018 2 Abstract With recent advances in technologies and methodologies, proteomics, which is the large-scale analysis of proteins, has been continuously developed in the field of bioinformatics, biotherapeutics and biomarker discovery. Top-down proteomics, which focuses on the analysis of intact proteins, has emerged within the last decade with significant advantages over the traditional bottom-up approach, such as the characterization of labile protein structures and the universal detection of all existing modifications. The front-end separation technologies for intact proteins are of the primary importance for the successful implementation of top-down proteomics. The work reported herein focuses the development of miniaturized liquid chromatography (LC) system and an effective and eco-friendly solvent system to address the challenges faced in intact protein separation and characterization. Electrospun nanofibers featuring effective chromatographic performance as the stationary phase of the ultrathin layer chromatography (UTLC) was developed in this work for the separation of amino acids and intact proteins. Nafion, a synthetic perfluorinated cationic polymer, was incorporated into a carrier polymer, polyacrylonitrile (PAN), to fabricate the nanofibrous stationary phase via electrospinning method. The separation of charged amino acids and proteins on the Nafion-PAN UTLC was based on the ion exchange mechanism (IEX).
    [Show full text]
  • Discovery of the Selenium Isotopes
    Discovery of the Selenium Isotopes J. Claes, J. Kathawa, M. Thoennessen∗ National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA Abstract Thirty-one selenium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented. ∗Corresponding author. Email address: [email protected] (M. Thoennessen) Preprint submitted to Atomic Data and Nuclear Data Tables April 28, 2010 Contents 1. Introduction . 3 2. Discovery of 64−94Se.................................................................................... 3 2.1. 64Se............................................................................................. 3 2.2. 65Se............................................................................................. 3 2.3. 66Se............................................................................................. 5 2.4. 67Se............................................................................................. 5 2.5. 68Se............................................................................................. 5 2.6. 69Se............................................................................................. 5 2.7. 70Se............................................................................................. 5 2.8. 71Se............................................................................................
    [Show full text]
  • Appendix 1 Glossary of Chromatographic Terms
    Appendix 1 Glossary of chromatographic terms Definition of chromatography, IUPAC (1993) "Chromatography is a physical method of separation in which the components to be separated are distributed between two phases, one of which is stationary while the other moves in a definite direction." Adjusted retention time t~, also known as corrected retention time, takes into account the dead time tM of the column; see retention time and dead time. t~ = tR - tM Adsorption chromatography mode of separation in which a solute or sample components are attracted to a solid surface, the stationary phase, by adsorp­ tion retention forces, the mobile phase may be a gas or liquid. Adsorption retention forces attraction of a solute onto a solid stationary phase due to microporosity (pores 5~ 50 nm) and polar character (formation of van der Waal's forces and hydrogen bonding) of the surface, described by Langmuir isotherms (see isotherms). Affinity chromatography separation effected by affinity of solute molecules for a bio-specific stationary phase consisting of complex organic molecules bonded to an inert support material, e.g. separation of proteins on a bonded antibody stationary phase. The technique is really selective filtration rather than chromatography. Alumina A120 3, slightly basic adsorbent used in liquid chromatography, particularly TLC, as a less acidic alternative to silica gel. Anion exchange chromatography see ion exchange chromatography. Asymmetry, As term used to describe non-symmetrical peaks measured by obtaining the ratio at 10% peak height h of the forward part, a and the rear part, b of a peak measured from the perpendicular line drawn from the peak maxima to the baseline.
    [Show full text]
  • Proceedings of the 1990 Billings Land Reclamation Symposium On
    U.S. GEOLOGICAL SURVEY CI-RCULAR 1064 Proceedings of the 1990 Billings Land Reclamation Symposium on Selenium in Arid and Semiarid Environments, Western United States AVAILABILITY OF BOOKS AND MAP OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with prices of the Jast offerings, arc·Jive!l in the cur­ rent-year issues of the monthly catalog "New Publications of th U.S. Geological Survey." Prices of available U.l:~ Sur· .­ vey publications released prior to the current year are listed in e most recent annual "Price and Availability List" Puhlications that are listed in various U.S. Geological Survey catalogs (see b ck inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. Prices of reports released to the open files are ~iven in the li ting "U.S. Geological Survey Open-File Reports,'~ updated month­ ly, which is for sale in microfiche froiD the U.S. Geological S ey, Books and Open-File Reports Section, Federal Center, Box 25425, Denver, CO 80225. Reports released through the NTIS y be obtained by writing to the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161 please include NTIS report numbez with inquiry. Order U.S. Geological Survey publications by mail or over the counter from the offices given below. BY MAIL OVER THE COUNTER Books Books Professional Papers, Bulletins, Water-Supply Papers, Techniqu of Water-Resources Investigations, Circulars, publications of general in Books of the
    [Show full text]
  • Selenium and Tellurium Content of Stony Meteorites by Neutron Activation
    Geochimicaet CosmochimicaActa, 1900, Vol. 19, py. 135 to 138. PeryamonPress Ltd. Priutedin NorthernIreland Selenium and tellurium content of stony meteorites by neutron activation U. SCHINDEWOLF* Department of Chemistry, University of Michigan, Ann &bor, Michigan (Received 14 Jcrmary 1MO) Abstract-By neutron activation analysis the Se- tendTe-content of four chondritic nleteorites have been determined. The average content is 9.8 + 2.5 and 0.61 .jl I.7 p.p.m., mspectively. Thesevalues are lowerthan those alrea,dyreported in the literature. SEVERAL authors (SUESS and UREY, 1956) have published data on the relative abundance of the chemical elements. In theoretically deriving these abundances extensive use has been made of certain systematic properties of nuclei because the necessary experimental data are lacking or unsatisfactory. Reliable experimental values of the abundance of each element are of great interest to cosmologists since the abundances of the elements are the result of cosmic events and any useful theory of the origin of the elements has to account in detail for the abundance curve. A recent theory requires several different types of synthesizing processes in order to explain the features of the abundance curve (BURBIDGE et al., 1957; CAMERON, 1957). Two of these processes are different types of neutron capture. Neutron capture on a long time-scale is thought to be responsible for the abundance peaks at Y (fifty neutrons), La (eighty-two neutrons) and Pb (126 neutrons) while neutron capture on a very short time-scale produces abundance peaks (CORYELI,, 1956) at approximately Br, Xe and Pt. Since the abundance of bromine, krypton, iodine and xenon are inherently difficult to determine, reliable data on the abundances of selenium and tellurium would be valuable in establishing the magnitudes of the peak yields at Br and Xe.
    [Show full text]