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Quantitative Assay of Pu-239 and Pu-240 by Neutron Transmission Measurements

Abstract

A method for quantitative assay of 239Pu and 240Pu has been tested at the reactor R1 in Stockholm. The method makes use of a fast chopper to measure the neutron transmission through a sample around the main resonances of these two isotopes - at 0.296 eV in 239Pu and at 1.056 eV in 240Pu. The transmission data measured are then combined with the known resonance cross sections to give the content of the isotopes. The method is nondestructive, i.e., one can use fuel pins as samples, even highly irradiated ones. A time-of-flight spectrometer of moderate capacity, like our fast chopper, is sufficient as the resonances are located at low energy. Altogether five samples have been used in the tests of the method. The results have been compared with mass spectrometer values. This comparison came out quite well for 239Pu whereas the chopper results for 240Pu were more than 10 per cent higher than the mass spectrometer results. This large deviation might be due to errors in the resonance cross section for 240Pu used in the analysis of the transmission data from the chopper. The best possible accuracy for a 15-hour run with our equipment is +- 1 per cent for  More>>
Authors:
Publication Date:
Apr 15, 1971
Product Type:
Technical Report
Report Number:
AE-416
Resource Relation:
Other Information: 20 refs., 6 figs., 8 tabs.
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; PLUTONIUM 240; PLUTONIUM 239; NEUTRON CHOPPERS; ACCURACY; QUANTITATIVE CHEMICAL ANALYSIS; FUEL PINS
OSTI ID:
922479
Research Organizations:
AB Atomenergi, Nykoeping (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
TRN: SE0808024
Availability:
Commercial reproduction prohibited; OSTI as DE00922479
Submitting Site:
SWDN
Size:
30 pages
Announcement Date:
Jan 25, 2008

Citation Formats

Johansson, E. Quantitative Assay of Pu-239 and Pu-240 by Neutron Transmission Measurements. Sweden: N. p., 1971. Web.
Johansson, E. Quantitative Assay of Pu-239 and Pu-240 by Neutron Transmission Measurements. Sweden.
Johansson, E. 1971. "Quantitative Assay of Pu-239 and Pu-240 by Neutron Transmission Measurements." Sweden.
@misc{etde_922479,
title = {Quantitative Assay of Pu-239 and Pu-240 by Neutron Transmission Measurements}
author = {Johansson, E}
abstractNote = {A method for quantitative assay of 239Pu and 240Pu has been tested at the reactor R1 in Stockholm. The method makes use of a fast chopper to measure the neutron transmission through a sample around the main resonances of these two isotopes - at 0.296 eV in 239Pu and at 1.056 eV in 240Pu. The transmission data measured are then combined with the known resonance cross sections to give the content of the isotopes. The method is nondestructive, i.e., one can use fuel pins as samples, even highly irradiated ones. A time-of-flight spectrometer of moderate capacity, like our fast chopper, is sufficient as the resonances are located at low energy. Altogether five samples have been used in the tests of the method. The results have been compared with mass spectrometer values. This comparison came out quite well for 239Pu whereas the chopper results for 240Pu were more than 10 per cent higher than the mass spectrometer results. This large deviation might be due to errors in the resonance cross section for 240Pu used in the analysis of the transmission data from the chopper. The best possible accuracy for a 15-hour run with our equipment is +- 1 per cent for 239Pu and +- 2 per cent for 240Pu, obtained for thick samples - about 3 x 1020 atoms per cm2 for each isotope. The accuracy corresponds to 68 per cent confidence level and does not include any contribution from the uncertainty in the resonance cross section}
place = {Sweden}
year = {1971}
month = {Apr}
}