Expected total counts for the Self-Interrogation Neutron Resonance Densitometry measurements of spent nuclear fuel
- Belgian nuclear research centre SCK.CEN (Belgium)
- Belgian nuclear research centre SCK.CEN. Boeretang 200, 2400 Mol (Belgium)
- Universite Libre de Bruxelles. Av. F. D. Roosevelt 50, B1050 Brussels (Belgium)
The Self-Interrogation Neutron Resonance Densitometry (SINRD) is a passive neutron technique that aims at a direct quantification of {sup 239}Pu in spent fuel assemblies by measuring the attenuation of the neutron flux in the energy region close to the 0.3 eV resonance of {sup 239}Pu. The {sup 239}Pu mass is estimated by calculating the SINRD signature, that is the ratio between the neutron counts in the fast energy region and around the 0.3 eV resonance region. The SINRD measurement approach in this study consisted in introducing a small neutron detector in the central guide tube of a PWR 17x17 fuel assembly. In order to measure the neutron flux in the energy regions defined in the SINRD signature, different detector types were used. The response of a bare {sup 238}U fission chamber is considered for the determination of the fast neutron flux, while other thermal-epithermal detectors wrapped in neutron absorbers are envisaged to measure the neutron flux around the resonance region. This paper provides an estimation of the total neutron counts that can be achieved with the detector types proposed for the SINRD measurement. In the first section a set of detectors are evaluated in terms of total neutron counts and sensitivity to the {sup 239}Pu content, in order to identify the optimal measurement configuration for each detector type. Then a study is performed to increase the total neutron counts by increasing the detector size. The study shows that the highest total neutron counts are achieved by using either {sup 3}He or {sup 10}B proportional counters because of the high neutron efficiency of these detectors. However, the calculations indicate that the biggest contribution to the measurement uncertainty is due to the measurement of the fast neutron flux. Finally, similar sensitivity to the {sup 239}Pu content is obtained by using the different detector types for the measurement of the neutron flux close to the resonance region. Therefore, the total neutron counts associated to each detector type will play a major role in the selection of the detector types used for the SINRD measurement. (authors)
- Research Organization:
- Institute of Electrical and Electronics Engineers - IEEE, 3 Park Avenue, 17th Floor, New York, N.Y. 10016-5997 (United States)
- OSTI ID:
- 22531509
- Report Number(s):
- ANIMMA-2015-IO-x6; TRN: US16V0521102450
- Resource Relation:
- Conference: ANIMMA 2015: 4. International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, Lisboa (Portugal), 20-24 Apr 2015; Other Information: Country of input: France; 16 Refs.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
ATTENUATION
BORON 10
FAST NEUTRONS
FISSION CHAMBERS
GUIDE TUBES
HE-3 COUNTERS
NEUTRON ABSORBERS
NEUTRON FLUX
PLUTONIUM 239
PWR TYPE REACTORS
SENSITIVITY
SPENT FUELS
URANIUM 238