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Title: Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing

Abstract

The ANSI/HPS N13.1–2011 standard requires gaseous tracer uniformity testing for sampling associated with stacks used in radioactive air emissions. Sulfur hexafluoride (SF 6), a greenhouse gas with a high global warming potential, has long been the gas tracer used in such testing. To reduce the impact of gas tracer tests on the environment, nitrous oxide (N 2O) was evaluated as a potential replacement to SF 6. The physical evaluation included the development of a test plan to record percent coefficient of variance and the percent maximum deviation between the two gases while considering variables such as fan configuration, injection position, and flow rate. Statistical power was calculated to determine how many sample sets were needed, and computational fluid dynamic modeling was utilized to estimate overall mixing in stacks. Results show there are no significant differences between the behaviors of the two gases, and SF 6 modeling corroborated N 2O test results. Although, in principle, all tracer gases should behave in an identical manner for measuring mixing within a stack, the series of physical tests guided by statistics was performed to demonstrate the equivalence of N 2O testing to SF 6 testing in the context of stack qualification tests. In conclusion,more » the results demonstrate that N 2O is a viable choice leading to a four times reduction in global warming impacts for future similar compliance driven testing.« less

Authors:
 [1]; ORCiD logo [1];  [1];  [1];  [1];  [1];  [2]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Glissmeyer Environmental, LLC, Kennewick, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1416970
Report Number(s):
PNNL-SA-128014
Journal ID: ISSN 1352-2310; PII: S1352231017308567
Grant/Contract Number:
AC05-76RL01830
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Atmospheric Environment (1994)
Additional Journal Information:
Journal Name: Atmospheric Environment (1994); Journal Volume: 176; Journal Issue: C; Journal ID: ISSN 1352-2310
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; ANSI/HPS N13.1–2011; Gaseous tracer testing; Global warming potential; N2O; SF6; Standards

Citation Formats

Yu, Xiao-Ying, Barnett, J. Matthew, Amidan, Brett G., Recknagle, Kurtis P., Flaherty, Julia E., Antonio, Ernest J., and Glissmeyer, John A. Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing. United States: N. p., 2017. Web. doi:10.1016/J.ATMOSENV.2017.12.015.
Yu, Xiao-Ying, Barnett, J. Matthew, Amidan, Brett G., Recknagle, Kurtis P., Flaherty, Julia E., Antonio, Ernest J., & Glissmeyer, John A. Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing. United States. doi:10.1016/J.ATMOSENV.2017.12.015.
Yu, Xiao-Ying, Barnett, J. Matthew, Amidan, Brett G., Recknagle, Kurtis P., Flaherty, Julia E., Antonio, Ernest J., and Glissmeyer, John A. 2017. "Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing". United States. doi:10.1016/J.ATMOSENV.2017.12.015. https://www.osti.gov/servlets/purl/1416970.
@article{osti_1416970,
title = {Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing},
author = {Yu, Xiao-Ying and Barnett, J. Matthew and Amidan, Brett G. and Recknagle, Kurtis P. and Flaherty, Julia E. and Antonio, Ernest J. and Glissmeyer, John A.},
abstractNote = {The ANSI/HPS N13.1–2011 standard requires gaseous tracer uniformity testing for sampling associated with stacks used in radioactive air emissions. Sulfur hexafluoride (SF6), a greenhouse gas with a high global warming potential, has long been the gas tracer used in such testing. To reduce the impact of gas tracer tests on the environment, nitrous oxide (N2O) was evaluated as a potential replacement to SF6. The physical evaluation included the development of a test plan to record percent coefficient of variance and the percent maximum deviation between the two gases while considering variables such as fan configuration, injection position, and flow rate. Statistical power was calculated to determine how many sample sets were needed, and computational fluid dynamic modeling was utilized to estimate overall mixing in stacks. Results show there are no significant differences between the behaviors of the two gases, and SF6 modeling corroborated N2O test results. Although, in principle, all tracer gases should behave in an identical manner for measuring mixing within a stack, the series of physical tests guided by statistics was performed to demonstrate the equivalence of N2O testing to SF6 testing in the context of stack qualification tests. In conclusion, the results demonstrate that N2O is a viable choice leading to a four times reduction in global warming impacts for future similar compliance driven testing.},
doi = {10.1016/J.ATMOSENV.2017.12.015},
journal = {Atmospheric Environment (1994)},
number = C,
volume = 176,
place = {United States},
year = 2017,
month =
}

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  • The Pacific Northwest National Laboratory (PNNL) conducted testing at two research and development (R&D) facilities where continuous sampling for radioactive air emissions is required. The testing was conducted to determine whether sampling system locations would meet the criteria for uniform air velocity and contaminant concentration in the American National Standard Institute (ANSI) standard, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities (ANSI/HPS N13.1-1999). The standard is a revision of the 1969 version that the facilities have been required to meet. The 1999 revision is drastically different from the 1969 version in itsmore » approach, requiring a well-mixed sampling location that must be demonstrated through performance tests that are specified in the standard. Testing at the 331 Facility was performed on the existing stack at the current sampling location; a scale model was built and used in place of the 325 Facility. Although both facilities’ sampling sites were compliant with the 1969 standard, only the 325 Facility met the criteria of the revised standard.« less
  • The ANSI N13.1 {open_quotes}Guide to Sampling Airborne Radioactive Materials in Nuclear Facilities{close_quotes} is currently being revised and is approaching the end of the revision process. The revision is being drafted by a working group under the auspices of the Health Physics Society Standards Committee. The main differences between the original and revised standards arc a narrowed scope, a greater emphasis on the design process, and the verification of meeting the performance criteria. The new scope is focused on air sampling from stacks or ducts and the new title is {open_quotes}Guide to Monitoring Releases of Radioactive Substances from Stacks and Ductsmore » of Nuclear Facilities.{close_quotes} The approach taken in the revision is essentially based on meeting performance criteria as opposed to following design prescriptions as was done in the past. This standard presents a new approach Lo representative sampling. The goal of achieving a representative sample is accomplished by requiring that samples are extracted from air streams meeting rigorous criteria for being well mixed for potential airborne contaminants. This standard sets forth guidelines and performance criteria for the use of air sampling nozzles, transport lines, sample collection and monitoring devices, and gas flow measuring methods in obtaining valid measurements of airborne radioactive materials in ducts or stacks. The presentation will online the fundamental principles incorporated in the draft revised standard.« less
  • Clause 6.4.4 in the American National Standards Institute / Health Physics Society (ANSI/HPS) N13.1 standard, Sampling and Monitoring Releases of Airborne Radioactive Substances From the Stacks and Ducts of Nuclear Facilities, addresses the internal smoothness of sample transport lines present between the nozzle and the analyzer (or collector). This paper evaluates the appropriateness of this clause by comparing roughness length of various materials against the required relative roughness, and by conducting computational fluid dynamic modeling. The results indicate that the inclusion of numerical criteria for the relative roughness of pipe by the ANSI Standard N13.1 (Section 6.4.4) is not appropriate.more » Recommended alternatives would be elimination of the numerical criteria, or modification of the standard to include a variable criteria for relative roughness.« less