Measurement of the plutonium hold-up in glove box before dismantling - 15111

Conference · Wed Jul 01 04:00:00 EDT 2015

OSTI ID:22822671

Chevillon, J.; Oddou, R.; Schoech, H.; Vincent, M. ^[1]

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1. CEA DAM DIF, F-91297 Arpajon cedex (France)

The French Bruyeres-Le-Chatel CEA (Commissariat a l'Energie Atomique et aux Energies Alternatives - French Alternatives Energies and Atomic Energy Commission) research center is going through a period of cleaning and dismantling of theses old treatment facilities on fissile materials and others associated nuclides. Some very large glove boxes contained some machines like melting furnace which can't be moved and are dismantled in situ. We need to evaluate the quantity of fissile materials to prevent criticality risk, to bring the evidence to the safety authority, to manage for the best the radioprotection of the workers and to manage waste production. A melting furnace in a glove box was dismantled. Measurements by gamma spectrometry with an HPGe detector (High Purity Germanium) and passive neutron counting (coincidence counting with shift register) are done in situ (furnace in the glove box). In order to refine the measurements, some data acquisitions by sector of glove box were carried out. In view of the geometries to characterize, some modelings have been created, in order to correct the different attenuations and to determine the plutonium masses content in the glove box, including the use of infinite energy technique. For the measurement by passive neutron counting (coincidence counting with shift register), we have used two slabs in high density polythene including nine He3 counters in each slab. This measurement technique is complementary to gamma spectrometry, and allows quantizing the fissile material which would be included in interstice of high Z material. The 100-L and 200-L drums produced during the dismantling were also measured. Based on simplified assumptions to analyze in situ measurements, plutonium weight could be evaluated. This approach of measurement in amount, during and after dismantling, has allowed to quantize the fissile material mass present in the glove box and didn't produce waste package which wouldn't respected the technical specifications of storage outlets. The results show good agreement between in situ and waste measurements. (authors)

• Research Organization: WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
• OSTI ID: 22822671
• Report Number(s): INIS-US--19-WM-15111
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
61 RADIATION PROTECTION AND DOSIMETRY
CEA
CLEANING
COINCIDENCE METHODS
CRITICALITY
DATA ACQUISITION
FISSILE MATERIALS
FURNACES
GAMMA SPECTROSCOPY
GLOVEBOXES
GLOVES
HAZARDS
HE-3 COUNTERS
HIGH-PURITY GE DETECTORS
MELTING
PERSONNEL
PLUTONIUM
POLYETHYLENES
SAFETY
STORAGE