Comparison of Activity Determination of Radium 226 in FUSRAP Soil using Various Energy Lines - 12299

Conference · Sun Jul 01 04:00:00 EDT 2012

OSTI ID:22293574

Tucker, Brian ^[1]; Donakowski, Jough ^[2]; Hays, David ^[3]

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1. Shaw Environmental and Infrastructure, Stoughton, MA 02072 (United States)
2. Unites States Army Corps of Engineers, Kansas City, MO 64106 (United States)
3. United States Army Corps of Engineers, Maywood, NJ 07607 (United States)

Gamma spectroscopy is used at the Formerly Utilized Sites Remedial Action Program (FUSRAP) Maywood Superfund Site as the primary radioanalytical tool for quantization of activities of the radionuclides of concern in site soil. When selecting energy lines in gamma spectroscopy, a number of factors are considered including assumptions concerning secondary equilibrium, interferences, and the strength of the lines. The case of the Maywood radionuclide of concern radium-226 (Ra-226) is considered in this paper. At the FUSRAP Maywood Superfund Site, one of the daughters produced from radioactive decay of Ra-226, lead-214 (Pb- 214), is used to quantitate Ra-226. Another Ra-226 daughter, bismuth-214 (Bi-214), also may be used to quantitate Ra-226. In this paper, a comparison of Ra-226 to Pb-214 activities and Ra-226 to Bi-214 activities, obtained using gamma spectrometry for a large number of soil samples, was performed. The Pb-214, Bi-214, and Ra-226 activities were quantitated using the 352 kilo electron volt (keV), 609 keV, and 186 keV lines, respectively. The comparisons were made after correcting the Ra-226 activities by a factor of 0.571 and both ignoring and accounting for the contribution of a U-235 interfering line to the Ra-226 line. For the Pb-214 and Bi-214 activities, a mean in-growth factor was employed. The gamma spectrometer was calibrated for efficiency and energy using a mixed gamma standard and an energy range of 59 keV to 1830 keV. The authors expect other sites with Ra-226 contamination in soil may benefit from the discussions and points in this paper. Proper use of correction factors and comparison of the data from three different gamma-emitting radionuclides revealed agreement with expectations and provided confidence that using such correction factors generates quality data. The results indicate that if contamination is low level and due to NORM, the Ra-226 can be measured directly if corrected to subtract the contribution from U-235. If there is any indication that technologically enhanced uranium may be present, the preferred measurement approach for quantitation of Ra-226 activity is detection of one of the Ra-226 daughters, Pb-214 or Bi-214, using a correction factor obtained from an in-growth curve. The results also show that the adjusted Ra-226 results compare very well with both the Pb-214 and Bi-214 results obtained using an in-growth curve correction factor. (authors)

• Research Organization: WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
• OSTI ID: 22293574
• Report Number(s): INIS-US--14-WM-12299
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
54 ENVIRONMENTAL SCIENCES
BISMUTH 214
COMPARATIVE EVALUATIONS
CONTAMINATION
DETECTION
EFFICIENCY
GAMMA SPECTROSCOPY
KEV RANGE
LEAD 214
NUCLEAR DECAY
RADIUM 226
REMEDIAL ACTION
URANIUM
URANIUM 235