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Title: Measurements of radionuclides in Pond C with an underwater HPGe detector

Abstract

This study on Pond C is part of a broader effort to appraise Savannah River Site (SRS) waterways impacted by the Par Pond Dam remediation program that commenced 1991. In addition, the results were sought to provide a more complete appraisal of the status of historical radioactive releases that remain in the Lower Three Runs system. Gamma emitting radionuclide concentrations in Pond C sediment were measured with an underwater HPGe detector. The predominant radionuclide was Cs-137 and the only other radionuclide detected was Co-60, which was only 1% as intense as the Cs-137. At the time of the measurements (November 1992), the total Pond C inventory of {sup 137}Cs was 4.5 {plus_minus} 0.8 Ci of which 0.30 {plus_minus} 0.09 Ci was exposed during a 6-ft drawdown for Par Pond Dam repairs. The Pond C inventory of Cs-137 is only 10% of that of Par Pond, primarily because of the much larger area of Par Pond. However, Pond C has a larger average sediment concentration of 8.1 {mu}Ci/m{sup 2} compared to 4.5 {mu}Ci/m{sup 2} for Par Pond, which is consistent with Pond C being closer to the origins of the earlier SRS reactor releases. The maximum Cs-137 concentration observed for Pondmore » C was 55 {mu}Ci/m{sup 2}, which is about 10% higher than the maximum observed for Par Pond.« less

Authors:
Publication Date:
Research Org.:
Westinghouse Savannah River Co., Aiken, SC (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
125172
Report Number(s):
WSRC-TR-95-0272
ON: DE96001653; TRN: 96:000016
DOE Contract Number:
AC09-89SR18035
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Aug 1995
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 40 CHEMISTRY; PONDS; QUALITATIVE CHEMICAL ANALYSIS; CESIUM 137; COBALT 60; CONTAMINATION; DETECTION; INVENTORIES; STATISTICAL DATA

Citation Formats

Winn, W.G.. Measurements of radionuclides in Pond C with an underwater HPGe detector. United States: N. p., 1995. Web. doi:10.2172/125172.
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Winn, W.G.. Measurements of radionuclides in Pond C with an underwater HPGe detector. United States. doi:10.2172/125172.
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Winn, W.G.. Tue . "Measurements of radionuclides in Pond C with an underwater HPGe detector". United States. doi:10.2172/125172. https://www.osti.gov/servlets/purl/125172.
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@article{osti_125172,
title = {Measurements of radionuclides in Pond C with an underwater HPGe detector},
author = {Winn, W.G.},
abstractNote = {This study on Pond C is part of a broader effort to appraise Savannah River Site (SRS) waterways impacted by the Par Pond Dam remediation program that commenced 1991. In addition, the results were sought to provide a more complete appraisal of the status of historical radioactive releases that remain in the Lower Three Runs system. Gamma emitting radionuclide concentrations in Pond C sediment were measured with an underwater HPGe detector. The predominant radionuclide was Cs-137 and the only other radionuclide detected was Co-60, which was only 1% as intense as the Cs-137. At the time of the measurements (November 1992), the total Pond C inventory of {sup 137}Cs was 4.5 {plus_minus} 0.8 Ci of which 0.30 {plus_minus} 0.09 Ci was exposed during a 6-ft drawdown for Par Pond Dam repairs. The Pond C inventory of Cs-137 is only 10% of that of Par Pond, primarily because of the much larger area of Par Pond. However, Pond C has a larger average sediment concentration of 8.1 {mu}Ci/m{sup 2} compared to 4.5 {mu}Ci/m{sup 2} for Par Pond, which is consistent with Pond C being closer to the origins of the earlier SRS reactor releases. The maximum Cs-137 concentration observed for Pond C was 55 {mu}Ci/m{sup 2}, which is about 10% higher than the maximum observed for Par Pond.},
doi = {10.2172/125172},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 01 00:00:00 EDT 1995},
month = {Tue Aug 01 00:00:00 EDT 1995}
}
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Technical Report:
View Technical Report (1.11 MB)
DOI:  10.2172/125172
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  • Savannah River Site (SRS) effluent gamma emitting radionuclides in Par Pond sediment were examined in situ with an underwater HPGe detector prior to and following a 19 ft drawdown of the pond in 1991 to address dam repairs. These measurements provide a map of the {sup 137}Cs concentrations of the pond sediment, indicating that 9.4 {plus_minus} 1.5 Ci is exposed by the drawdown and that 46.6 {plus_minus} 7.2 Ci is the entire pond inventory. The highest individual {sup 137}Cs concentration was 25 {mu}Ci/m{sup 2} for the exposed sediment and 50 {mu}Ci/m{sup 2} for the entire pond. The results are consistentmore » with parallel studies conducted by SREL, as well as historical data. Aside from {sup 137}Cs, the only other SRS-produced isotope observed was {sup 60}Co, with activity of only about 1% of that for {sup 137}Cs. This observation was also confirmed in grab samples of pond sediment and vegetation, which were returned to the laboratory for ultra-low-level gamma spectrometry analysis. A special effort was required to calibrate the underwater HPGe detector, where both measurements and calculational models were used. The effects of sediment depth profiles for density and {sup 137}Cs concentration were addressed in the calibration. Calibration factors for sediment surface concentrations ({mu}Ci/m{sup 2}/cpm) and sediment mass concentrations (pCi/kg/cpm) were obtained. In general, the {mu}Ci/m{sup 2}/cpm factor is recommended, as the pCi/kg/cpm factor depends on the depth location of the sediment of interest. However, a pCi/kg/cpm factor, which is dependent on the depth within the sediment is presented to address dose calculations that require it.« less

  • ; ;
    This study of L Lake was conducted to determine whether the distribution of man-made radiation levels had changed from the time preceding the filling of the newly created lake in 1985. Overflight gamma measurements by EG&G in 1985 mapped the man-made radiation levels, indicating that significant levels were only detected from former stream beds that were to be covered by the lake. the present scoping gamma measurements were consistent with these earlier findings, indicating no major evidence of movement of the radioactivity. These results will be available to guide decisions concerning future plans for the lake. Gamma-emitting radionuclides of Lmore » Lake were examined in situ with an underwater HPGe detector and further studied by retrieving various sediment samples for analysis by HPGe gamma spectrometry in the Underground Counting Facility. The predominant man-made radionuclide detected was {sup 137}Cs; it had about 100 times greater activity than {sup 60}Co, which was the only other man-made radionuclide that was detected above trace levels.« less

  • - Transactions of the American Nuclear Society; (United States)
    At the Savannah River Site during the past year, an underwater high-purity germanium (HPGe) detector was used to inventory [sup 137]Cs in sediment of a reactor cooling pond. Dam maintenance required lowering the water level of the pond by 6 m, and the gamma-emitting radionuclides in the exposed sediment needed preevaluation. Although earlier [sup 137]Cs data were available, there were no comprehensive underwater gamma spectrometric measurements of the sediment.

  • The amount of 137Cs was measured in the PAR pond on the Savannah River Site. An underwater HPGe detector was used to inventory the gamma-emitting radionuclides in the sediment of the pond. The description and process of the equipment was given in this report. From the analysis of the compiled data, the drawdown can proceed in radiological guide lines.

  • The amount of 137Cs was measured in the PAR pond on the Savannah River Site. An underwater HPGe detector was used to inventory the gamma-emitting radionuclides in the sediment of the pond. The description and process of the equipment was given in this report. From the analysis of the compiled data, the drawdown can proceed in radiological guide lines.