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U.S. Department of Energy
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Non-destructive assay of leached hulls in a nuclear fuel reprocessing plant

Conference ·
OSTI ID:6809846
The hull monitor at the Barnwell Nuclear Fuels Plant (BNFP) will be a remotely controlled, fully automated system designed to quantitatively assay leached hulls for undissolved U and Pu. The hull monitor will assay the hulls from one metric ton of fuel per dissolver basket with the design goal of detecting 0.1% undissolved fuel and yet remain within the framework of the BNFP materials flow of five hull baskets per day. The non-destructive assay will be accomplished using a computer-based gamma-ray pulse height analysis system employing a 5 x 5 inch NaI(Tl) scintillation detector. The intense radiations from the fission product isotopes and the activation product isotopes produced in the reactor prevent direct assay of the undissolved fuel left in the hulls. The measurement will be made indirectly by demonstrating a correlation between the amount of /sup 144/Ce undissolved and the remaining U. The isotope /sup 144/Ce is a direct fission product with high cumulative yield. The daughter isotope /sup 144/Pr has a gamma ray at 2.18 MeV well above other predominant radiations in the spectrum from the major interferences /sup 60/Co, /sup 58/Co, /sup 95/Zr(/sup 95/Nb), /sup 137/Cs and /sup 106/Ru(/sup 106/Rh). Segmented scanning operation of the hull monitor is accomplished by rotation and vertical transversal of the hulls container past the detector station. Proper collimation and absorbers are required to maximize the /sup 144/Ce(/sup 144/Pr) to background ratio. A basket indexer is provided which monitors the scanning rate and ensures repositioning. The leached hull monitor system will be interfaced to a computer-based multichannel analyzer for ease of operation and data handling. A calibration basket has been fabricated to accomodate radioactive sources and inactive Zircaloy hulls.
Research Organization:
Allied-General Nuclear Services, Barnwell, S.C. (USA)
Sponsoring Organization:
USDOE
DOE Contract Number:
ET-78-C-09-1040
OSTI ID:
6809846
Report Number(s):
AGNS--1040-4; CONF-780522--2
Country of Publication:
United States
Language:
English