Validation testing of Canberra-Obayashi TruckScan calculation method - 15409
- Canberra Japan K.K. (Japan)
- Canberra Industries Inc (United States)
- Obayashi Corporation (Japan)
Canberra Industries, Inc. [CI] has designed a new truck monitoring system 'TruckScan' for Interim Storage Facilities [ISF] in Japan. CI and Canberra Japan K.K. [CJKK] have performed validation testing of it with Obayashi Corporation at a temporary storage area in Fukushima prefecture. Decontaminated waste was put into flexible containers called Super Sacks [SS]. The customer desires to quantify the Cs-137 and Cs-134 content of each individual SS, while a group of them are on a truck. This would be done when leaving a temporary waste consolidation area and entering an ISF. The content of SSs is some combination of sand, soil, and vegetation with densities ranging from 0.3 g/cc - 1.6 g/cc. The typical weight of the trucks will be approximately 10 tons, but can vary between 4 and 20 tons. The system must be sensitive enough to detect 100 Bq/kg in 10 - 30 seconds but still have enough dynamic range to measure 1,000,000 Bq/kg material. The system will be operated in an outdoor environment. The desire to separately quantify Cs-137 and Cs-134 favors the use of a spectroscopic system as a solution. The full-scale TruckScan will consist of eight 3x3' NaI detectors, each in a lead shield with a collimated view of the truck. Four detectors are on each side of the truck, at about 1 meter from the truck, spaced at equal distances. These NaI detectors and collimators were calibrated by In Situ Object Counting System (ISOCS) mathematical efficiency calculation tool. The truck stops in-between the two sets of detectors for the short measurement period - typically 15 seconds. The special software performs gamma spectroscopy on each of the 8 spectra, and then decodes the results to determine the activity in each of the 8 [typically] SSs using a Maximum Entropy Analysis Method. Validation testing was done by using SSs filled with known material types and known concentrations of material. The results of the TruckScan assay indicate good accuracy for the wide range of conditions. In spite of the conditions being more severe than normal operations, the combined standard deviation was 20.1% for the 6 detector version and 16.6% for the 8 detector version TruckScan. When the TruckScan results were compared to the known concentrations, there was minimal bias and good correlation [y = 1.0029x, R{sup 2} = 0.914]. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 22824319
- Report Number(s):
- INIS-US-19-WM-15409; TRN: US19V0891069365
- Resource Relation:
- Conference: WM2015: Annual Waste Management Symposium, Phoenix, AZ (United States), 15-19 Mar 2015; Other Information: Country of input: France; 6 refs.; available online at: http://archive.wmsym.org/2015/index.html
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CALCULATION METHODS
CESIUM 134
CESIUM 137
COLLIMATORS
COMPUTER CODES
CONCENTRATION RATIO
CONTAINERS
ENTROPY
GAMMA SPECTROSCOPY
MONITORING
NAI DETECTORS
PLANTS
SAND
SOILS
STORAGE FACILITIES
TRUCKS
WASTES