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Title: Completion of Kr-81 and Kr-85 Analysis Development for Hydrogeology and Testing its Validity by Assessing Aquifer Recharge Rates

Abstract

Summary The overall objective was to complete the development of a RIMS-based analytical technique to determine the concentration of the rare krypton radioisotopes, 81Kr and 85Kr, in samples of interest to the geoscience and planetary science community The key to RIMS is the use of tunable lasers to selectively and efficiently excite by resonant photon absorption atomic states unique to the chosen element. Ionization of the specified element can then occur while excluding all other constituents of the sample, bringing detection limits down to the single-atom level. Combining RIMS with several steps of isotopic enrichment makes detection of a rare isotope, such as 81Kr, feasible. A complete process for groundwater samples consists of starting with (1) collecting the groundwater sample, (2) degassing the water sample, (3) separating Kr from the recovered gases, (4 & 5) two isotopic enrichments reducing interfering isotopes by >109, and (6) detecting the rare krypton isotope using RIMS in a time-of-flight system. Required water sample size is 20 liters for 81Kr and 10 to 3 liters for 85Kr. Weak links in the above steps were to be identified and rectified. Most of the troublesome issues were resolved, but unfortunately, two key difficulties could not be resolvedmore » with the available resources, so the overall, final goal of completing a suite of measurements was not achieved. In spite of this, valuable collaborations were established to demonstrate the value of 81Kr and 85Kr measurements in two critical applications, the future site of a nuclear waste repository, where high efficiency 81Kr measurements would allow groundwater dating of low-yield formations, and a multi-method analysis of potential contamination inflow into a large municipal water system, where the simplicity of interpretation of 85Kr measurements could become a valuable future interpretive tool. Therefore, samples were collected anyway, and processing started using the working parts of the method, so that comparisons to other methods could be made in the future« less

Authors:
Publication Date:
Research Org.:
The University of Tennessee, Knoxville
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
902831
Report Number(s):
DOE/ER/15159-3
TRN: US0806203
DOE Contract Number:
FG02-01ER15159
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; 47 OTHER INSTRUMENTATION; ABSORPTION; AGE ESTIMATION; AQUIFERS; CONTAMINATION; DEGASSING; DETECTION; EFFICIENCY; GASES; IONIZATION; KRYPTON; KRYPTON ISOTOPES; LASERS; PHOTONS; RADIOACTIVE WASTES; RADIOISOTOPES; SENSITIVITY; TESTING; WATER; Kr-81 Analysis; Kr-85 Analysis; Rare noble gas isotopes; Age-dating; Groundwater; Polar Ice; Hazardous waste repository assessment

Citation Formats

Thonnard, Norbert. Completion of Kr-81 and Kr-85 Analysis Development for Hydrogeology and Testing its Validity by Assessing Aquifer Recharge Rates. United States: N. p., 2007. Web. doi:10.2172/902831.
Thonnard, Norbert. Completion of Kr-81 and Kr-85 Analysis Development for Hydrogeology and Testing its Validity by Assessing Aquifer Recharge Rates. United States. doi:10.2172/902831.
Thonnard, Norbert. Sat . "Completion of Kr-81 and Kr-85 Analysis Development for Hydrogeology and Testing its Validity by Assessing Aquifer Recharge Rates". United States. doi:10.2172/902831. https://www.osti.gov/servlets/purl/902831.
@article{osti_902831,
title = {Completion of Kr-81 and Kr-85 Analysis Development for Hydrogeology and Testing its Validity by Assessing Aquifer Recharge Rates},
author = {Thonnard, Norbert},
abstractNote = {Summary The overall objective was to complete the development of a RIMS-based analytical technique to determine the concentration of the rare krypton radioisotopes, 81Kr and 85Kr, in samples of interest to the geoscience and planetary science community The key to RIMS is the use of tunable lasers to selectively and efficiently excite by resonant photon absorption atomic states unique to the chosen element. Ionization of the specified element can then occur while excluding all other constituents of the sample, bringing detection limits down to the single-atom level. Combining RIMS with several steps of isotopic enrichment makes detection of a rare isotope, such as 81Kr, feasible. A complete process for groundwater samples consists of starting with (1) collecting the groundwater sample, (2) degassing the water sample, (3) separating Kr from the recovered gases, (4 & 5) two isotopic enrichments reducing interfering isotopes by >109, and (6) detecting the rare krypton isotope using RIMS in a time-of-flight system. Required water sample size is 20 liters for 81Kr and 10 to 3 liters for 85Kr. Weak links in the above steps were to be identified and rectified. Most of the troublesome issues were resolved, but unfortunately, two key difficulties could not be resolved with the available resources, so the overall, final goal of completing a suite of measurements was not achieved. In spite of this, valuable collaborations were established to demonstrate the value of 81Kr and 85Kr measurements in two critical applications, the future site of a nuclear waste repository, where high efficiency 81Kr measurements would allow groundwater dating of low-yield formations, and a multi-method analysis of potential contamination inflow into a large municipal water system, where the simplicity of interpretation of 85Kr measurements could become a valuable future interpretive tool. Therefore, samples were collected anyway, and processing started using the working parts of the method, so that comparisons to other methods could be made in the future},
doi = {10.2172/902831},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Apr 28 00:00:00 EDT 2007},
month = {Sat Apr 28 00:00:00 EDT 2007}
}

Technical Report:

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  • A facility for measurement of rare Kr-81 and Kr-85 isotope concentration in hydrogeologic samples, and isotopic composition of minute quantities of krypton and xenon from extraterrestrial samples, was established, requiring refinement of an emerging mass spectrometric-based analytical technique and securing of laboratory space and equipment. The analytical process consists of (1) collecting a groundwater sample, (2) degassing the water, (3) separating Kr from the recovered gases, (4&5) two isotopic enrichments to reduce interfering isotopes by E9, and (6) detecting the rare krypton isotope in a unique time-of-flight mass spectrometer detecting as few as 100 Kr atoms. All equipment is installedmore » and operating, with only some additional adjustment and testing of the last step (6, above) remaining to be completed. Collaborations have been established with a number of researchers and organizations world wide, and both groundwater and extraterrestrial samples have been collected. Completion of analyses awaits full operation of step 6.« less
  • The report presents an analysis of the hydrogeology of the clastic Cretaceous Coastal Plain aquifers in parts of eastern Mississippi and western Alabama. This report provides descriptions of (1) the hydrogeologic framework and associated ground-water flow system and (2) a calibrated digital computer model capable of assessing the effects of ground-water withdrawals or other stresses on the ground-water flow system.
  • The Dakota Group aquifer of the Canon City embayment comprises two primary water-bearing units, the Lytle Sandstone Member at the base and the Dakota Sandstone at the top, separated by the semiconfining, arenaceous Glencairn Shale Member. The ground water in this area probably represents a mixture of some or all of the following genetic types: (1) ground water connate to the Dakota Group; (2) ground water, connate or otherwise, entering the aquifer as leakage from adjacent semiconfining strata; (3) deeply circulated meteoric ground water; and (4) hydrothermal fluids (magmatic or metamorphic ground water) purged from the crystalline basement complex underlyingmore » the embayment. The contents of the radium-226 in ground water from 117 wells completed in part or all of the Dakota Group were determined by the dissolved radon-222 emanation method. Sixty-seven percent of the ground water samples have radium-226 activities greater than 5.0 picocuries per liter of water (5.0 pCi/1), the recommended maximum permissible concentration of radium-226 in drinking water established by the Environmental Protection Agency in 1973. Inspection of gamma-ray logs of about 20 wells revealed the presence of moderate to extremely high gamma radiation in strata of the Dakota Group, the Morrison Formation, the Fountain Formation, and in the crystalline basement rocks. High levels of radium-226 in drinking water supplies pose potentially serious health hazards to the users. Owners of wells producing such water supplies are advised to (1) install, at the homesite, ion exchange (filtering units) capable of removing /sup 226/Ra/sup 2 +/ ions and other aqueous radium species from the water or (2) effectively case out those stratigraphic intervals in the bore hole showing high gamma radiation preventing possible radium-rich ground water within these intervals from entering the well.« less
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  • The city of San Antonio, Texas, is faced with an agonizing decision of how to protect its sole water source, the Edwards Aquifer, from the threat of pollution resulting from urban sprawl over the recharge zone of the aquifer. Recent urban growth to the north and northwest of San Antonio has intensified the concern for the protection of this pristine, high quality water resource. A decision analysis model has been structured in an effort to facilitate an objective analysis and to coordinate the judgements regarding a degree of satisfaction associated with each alternative available for the protection of San Antonio'smore » groundwater. Multiattribute utility function was used as an integrated measure of the effectiveness for various feasible alternatives. The necessary information was polled from the local water resources decision-makers through a series of cyclic opinions surveys based on the Delphi technique.« less