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Chen CF, Yang LT, Huang YJ, Shang-Guan ZH, Guo GY, Yao JL, Sha XD. A study on 85Kr measurement with an internal gas proportional counter. Appl Radiat Isot 2019; 155:108948. [PMID: 31655352 DOI: 10.1016/j.apradiso.2019.108948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 10/15/2019] [Accepted: 10/15/2019] [Indexed: 10/25/2022]
Abstract
A measurement method of 85Kr using an internal gas proportional counter (IGPC) is presented in this study. The operation conditions of the IGPC were determined and optimized, including the operating voltage, pressure, sample volume, interference from other gas components such as nitrogen or air, and mitigation of the memory effect. The IGPC was calibrated using certified standards, and the detection efficiency was approximately 58% for typical samples. A lower limit of detection of approximately 0.11 MBq/m3(Kr) was achieved after counting for 5 h with 1 mL pure Kr, corresponding to the atmospheric activity concentration of 0.18 Bq/m3 (air). It was shown that the IGPC could be used effectively for measuring 85Kr.
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Affiliation(s)
- Chao-Feng Chen
- Suzhou Nuclear Power Research Institute Co., Ltd, Suzhou, 215004, China
| | - Li-Tao Yang
- Suzhou Nuclear Power Research Institute Co., Ltd, Suzhou, 215004, China
| | - Yan-Jun Huang
- Suzhou Nuclear Power Research Institute Co., Ltd, Suzhou, 215004, China.
| | | | - Gui-Ying Guo
- Suzhou Nuclear Power Research Institute Co., Ltd, Suzhou, 215004, China
| | - Jian-Lin Yao
- Suzhou Nuclear Power Research Institute Co., Ltd, Suzhou, 215004, China
| | - Xiang-Dong Sha
- Suzhou Nuclear Power Research Institute Co., Ltd, Suzhou, 215004, China
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Huang YJ, Guo GY, Chen CF, Yang LT, Shang-Guan ZH, Sha XD, Yao JL, Hu C. Automated separation and analysis of krypton-85 from low-volume gaseous effluent of nuclear power plant. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06838-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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3
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Marino BD, Mincheva M, Doucett A. California air resources board forest carbon protocol invalidates offsets. PeerJ 2019; 7:e7606. [PMID: 31579578 PMCID: PMC6761920 DOI: 10.7717/peerj.7606] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/02/2019] [Indexed: 11/20/2022] Open
Abstract
The commercial asset value of sequestered forest carbon is based on protocols employed globally; however, their scientific basis has not been validated. We review and analyze commercial forest carbon protocols, claimed to have reduced net greenhouse gas emissions, issued by the California Air Resources Board and validated by the Climate Action Reserve (CARB-CAR). CARB-CAR forest carbon offsets, based on forest mensuration and model simulation, are compared to a global database of directly measured forest carbon sequestration, or net ecosystem exchange (NEE) of forest CO2. NEE is a meteorologically based method integrating CO2 fluxes between the atmosphere, forest and soils and is independent of the CARB-CAR methodology. Annual carbon accounting results for CAR681 are compared with NEE for the Ameriflux site, Howland Forest Maine, USA, (Ho-1), the only site where both methods were applied contemporaneously, invalidating CARB-CAR protocol offsets. We then test the null hypothesis that CARB-CAR project population data fall within global NEE population values for natural and managed forests measured in the field; net annual gC m-2yr-1 are compared for both protocols. Irrespective of geography, biome and project type, the CARB-CAR population mean is significantly different from the NEE population mean at the 95% confidence interval, rejecting the null hypothesis. The CARB-CAR population exhibits standard deviation ∼5× that of known interannual NEE ranges, is overcrediting biased, incapable of detecting forest transition to net positive CO2 emissions, and exceeds the 5% CARB compliance limit for invalidation. Exclusion of CO2 efflux via soil and ecosystem respiration precludes a valid net carbon accounting result for CARB-CAR and related protocols, consistent with our findings. Protocol invalidation risk extends to vendors and policy platforms such as the United Nations Program on Reducing Emissions from Deforestation and Forest Degradation (REDD+) and the Paris Agreement. We suggest that CARB-CAR and related protocols include NEE methodology for commercial forest carbon offsets to standardize methods, ensure in situ molecular specificity, verify claims of carbon emission reduction and harmonize carbon protocols for voluntary and compliance markets worldwide.
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Affiliation(s)
- Bruno D.V. Marino
- Executive Management, Planetary Emissions Management Inc., Cambridge, MA, USA
| | - Martina Mincheva
- Department of Statistics, Philadelphia, PA, United States of America
| | - Aaron Doucett
- Planetary Emissions Management Inc., Cambridge, MA, USA
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de Aquino ABM, Leal LA, Carvalho-Silva VH, Gargano R, Ribeiro Junior LA, da Cunha WF. Krypton-methanol spectroscopic study: Assessment of the complexation dynamics and the role of the van der Waals interaction. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 205:179-185. [PMID: 30015023 DOI: 10.1016/j.saa.2018.06.110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/26/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
The Kr-CH3OH (Krypton-Methanol) system has several technological applications, such as the determination of diffusivity coefficients, their use in the development of detectors and combustion techniques among others. We report an extensive theoretical study concerning the stability of such complex. A mix between molecular dynamics, electronic structure calculations and solution of the nuclear Schrodinger equation lead to investigation of spectroscopic constants, lifetime of the complex and its Quantum Theory Atom in Molecules (QTAIM) properties. The study of the Potential Energy Curves (PEC) suggested three configurations to be stable as their potential well were able to harbor 9 vibrational levels. Properties from the curves also allowed us to obtain the lifetime of the complex, whose values were >1 ps regardless of the conformation. Furthermore, topological investigations of the charge density profile of the complex, in the scope of QTAIM properties, show that van der Waals type interactions takes place between the noble gas and the methanol molecule. These features are in consonance to the experimental fact that this complex is stable.
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Affiliation(s)
- Amanda Bárbara Mendes de Aquino
- Anapolis Group of Theoretical and Structural Chemistry, Goias State University - Exact Science and Technology Campus, Anapolis 75001-970, Brazil
| | | | - Valter H Carvalho-Silva
- Anapolis Group of Theoretical and Structural Chemistry, Goias State University - Exact Science and Technology Campus, Anapolis 75001-970, Brazil
| | - Ricardo Gargano
- Institute of Physics, University of Brasilia, Brasilia 70910-900, Brazil
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Schoeppner M, Glaser A. Present and future potential of krypton-85 for the detection of clandestine reprocessing plants for treaty verification. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 162-163:300-309. [PMID: 27318574 DOI: 10.1016/j.jenvrad.2016.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 06/06/2023]
Abstract
Burnup calculations are applied to determine the amount of krypton-85 that is produced during the irradiation of nuclear fuel. Since krypton-85 is most likely released into the atmosphere during reprocessing to separate plutonium, atmospheric transport modeling is used to calculate the worldwide distribution of krypton-85 concentrations stemming from emissions from declared reprocessing plants. The results are the basis for scenarios in which emissions from clandestine reprocessing facilities have to be detected against various background levels. It is concluded that today's background imposes heavily on the ability to detect small and medium plutonium separation rates; only high separation rates of 1 SQ per week and higher have a chance to be detected with feasible outlay. A fixed network of monitoring stations seems too costly; instead the high number of samples that are required rather calls for mobile sampling procedures, where air samples are collected at random locations over the world and are analyzed in regional laboratories for their krypton-85 concentration. Further, it is argued that krypton-85 emissions from declared reprocessing activities have to be significantly lowered to enable a worldwide verification of the absence of even smaller clandestine reprocessing. For each scenario the number of samples that have to be taken for probable detection is calculated.
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Affiliation(s)
- Michael Schoeppner
- Princeton University, Program on Science and Global Security, 221 Nassau St, Princeton, NJ 08542, USA.
| | - Alexander Glaser
- Princeton University, Program on Science and Global Security, 221 Nassau St, Princeton, NJ 08542, USA
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Tu LY, Yang GM, Zhang XY, Hu SM. Efficient Separation of Ar and Kr from Environmental Samples for Trace Radioactive Noble Gas Detection. CHINESE J CHEM PHYS 2016. [DOI: 10.1063/1674-0068/29/cjcp1510210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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7
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Affiliation(s)
- Zheng-Tian Lu
- Hefei National Laboratory for Physical Sciences at the Microscale, Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, China
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Sturchio NC, Kuhlman KL, Yokochi R, Probst PC, Jiang W, Lu ZT, Mueller P, Yang GM. Krypton-81 in groundwater of the Culebra Dolomite near the Waste Isolation Pilot Plant, New Mexico. JOURNAL OF CONTAMINANT HYDROLOGY 2014; 160:12-20. [PMID: 24594409 DOI: 10.1016/j.jconhyd.2014.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 02/08/2014] [Accepted: 02/11/2014] [Indexed: 06/03/2023]
Abstract
The Waste Isolation Pilot Plant (WIPP) in New Mexico is the first geologic repository for disposal of transuranic nuclear waste from defense-related programs of the US Department of Energy. It is constructed within halite beds of the Permian-age Salado Formation. The Culebra Dolomite, confined within Rustler Formation evaporites overlying the Salado Formation, is a potential pathway for radionuclide transport from the repository to the accessible environment in the human-disturbed repository scenario. Although extensive subsurface characterization and numerical flow modeling of groundwater has been done in the vicinity of the WIPP, few studies have used natural isotopic tracers to validate the flow models and to better understand solute transport at this site. The advent of Atom-Trap Trace Analysis (ATTA) has enabled routine measurement of cosmogenic (81)Kr (half-life 229,000 yr), a near-ideal tracer for long-term groundwater transport. We measured (81)Kr in saline groundwater sampled from two Culebra Dolomite monitoring wells near the WIPP site, and compared (81)Kr model ages with reverse particle-tracking results of well-calibrated flow models. The (81)Kr model ages are ~130,000 and ~330,000 yr for high-transmissivity and low-transmissivity portions of the formation, respectively. Compared with flow model results which indicate a relatively young mean hydraulic age (~32,000 yr), the (81)Kr model ages imply substantial physical attenuation of conservative solutes in the Culebra Dolomite and provide limits on the effective diffusivity of contaminants into the confining aquitards.
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Affiliation(s)
- Neil C Sturchio
- Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
| | - Kristopher L Kuhlman
- Repository Performance Department, Sandia National Laboratories, Carlsbad, NM 88220, USA
| | - Reika Yokochi
- Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Geophysical Sciences, The University of Chicago, Chicago, IL 60637, USA
| | - Peter C Probst
- Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Wei Jiang
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Zheng-Tian Lu
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA; Department of Physics and Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Peter Mueller
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Guo-Min Yang
- Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA; Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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Jiang W, Bailey K, Lu ZT, Mueller P, O'Connor TP, Purtschert R. Ion current as a precise measure of the loading rate of a magneto-optical trap. OPTICS LETTERS 2014; 39:409-412. [PMID: 24562159 DOI: 10.1364/ol.39.000409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have demonstrated that the ion current resulting from collisions between metastable krypton atoms in a magneto-optical trap can be used to precisely measure the trap loading rate. We measured both the ion current of the abundant isotope 83Kr (isotopic abundance=11%) and the single-atom counting rate of the rare isotope 85Kr (isotopic abundance∼1×10(-11)), and found the two quantities to be proportional at a precision level of 0.9%. This work results in a significant improvement in using the magneto-optical trap as an analytical tool for noble-gas isotope ratio measurements, and will benefit both atomic physics studies and applications in the earth sciences.
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Aprile E, Yoon T, Loose A, Goetzke LW, Zelevinsky T. An atom trap trace analysis system for measuring krypton contamination in xenon dark matter detectors. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:093105. [PMID: 24089814 DOI: 10.1063/1.4821879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We have developed an atom trap trace analysis (ATTA) system to measure Kr in Xe at the part per trillion (ppt) level, a prerequisite for the sensitivity achievable with liquid xenon dark matter detectors beyond the current generation. Since Ar and Kr have similar laser cooling wavelengths, the apparatus has been tested with Ar to avoid contamination prior to measuring Xe samples. A radio-frequency plasma discharge generates a beam of metastable atoms which is optically collimated, slowed, and trapped using standard magneto-optical techniques. Based on the measured overall system efficiency of 1.2 × 10(-8) (detection mode), we expect the ATTA system to reach the design goal sensitivity to ppt concentrations of Kr in Xe in <2 h.
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Affiliation(s)
- E Aprile
- Department of Physics, Columbia University, New York, New York 10027-5255, USA
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