Frisker Response to Soil Concentrations (Bq/g) Compared to NaI(Tl) - 19338
- Cox Nuclear Consulting Services (United States)
- Canadian Nuclear Laboratories (Canada)
The Chalk River Laboratories (CRL) began nuclear operations in 1947. Portions of the site land areas have become radiologically contaminated through the 1952 National Reactor Experimental (NRX) accident and/or waste management activities over the past 70 years of site operations. The Environmental Remediation Projects Group (ERP) characterizes, and performs risk assessment, and remedial actions, as required over these contaminated land areas. ERP work activities are subject to controls established by CRL's Radiation Protection (RP) Group such that RP establishes the radiological controls and monitoring requirements for ERP field work activities. The different methods of monitoring soil contamination between ERP and the RP program present some challenges in the interpretation and comparison of the two sets of results and the soil disposition. ERP utilizes NaI(Tl) scintillation detectors and MARSSIM land scanning techniques to measure soil concentrations between sample locations and in excavated materials. Whereas, RP utilizes surface contamination monitoring equipment in the form of a 15.5 cm{sup 2} open area pancake Geiger-Mueller (GM) tube detector to measure soil contamination levels reported in counts per minute (cpm). This paper presents a method to evaluate the theoretical best responses that could be obtained from surface contamination monitoring instrumentation for a known concentration (1 Bq/g) of various radionuclides. A static efficiency of cpm/Bq{sup -1} g{sup -1} is obtained from these calculations. These contamination monitoring sensitivities are then used in a MARSSIM scanning sensitivity equation and compared to the scanning sensitivity of an NaI(Tl) scintillation detector. The results demonstrate that the sensitivity of the frisker probes to particle radiations (betas for pancake) tend to fall in a range of only a few cpm/Bq{sup -1} g{sup -1}. Rather, the primary static response of the pancake probe to soil contamination is from gamma radiation where a value of 36 cpm/Bq{sup -1} g{sup -1} for Cs-137 was obtained at 2.54 cm distance without the application of scanning statistics. In comparison, a 7.6 cm x 7.6 cm NaI(Tl) detector has a Cs-137 static response factor of 10,000 cpm/Bq{sup -1} g{sup -1} at 15 cm distance without applying scanning statistics. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 23003073
- Report Number(s):
- INIS-US-21-WM-19338; TRN: US21V1189043406
- Resource Relation:
- Conference: WM2019: 45. Annual Waste Management Conference, Phoenix, AZ (United States), 3-7 Mar 2019; Other Information: Country of input: France; 7 refs.; available online at: https://www.xcdsystem.com/wmsym/2019/index.html
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
CESIUM 137
CHALK RIVER NUCLEAR LABS
ECOLOGICAL CONCENTRATION
EFFICIENCY
GAMMA RADIATION
RADIATION ACCIDENTS
RADIATION MONITORING
RADIATION PROTECTION
RADIOACTIVE WASTE MANAGEMENT
REMEDIAL ACTION
RISK ASSESSMENT
SCINTILLATIONS
SENSITIVITY
SODIUM IODIDES
SOILS
SURFACE CONTAMINATION