Evaluation of proliferation resistance of plutonium based on spontaneous fission neutron emission rate

2012 ◽  
Vol 46 ◽  
pp. 152-159 ◽  
Author(s):  
Yoshiki Kimura ◽  
Masaki Saito ◽  
Hiroshi Sagara ◽  
Chi Young Han
Keyword(s):  
Spontaneous Fission ◽  
Emission Rate ◽  
Neutron Emission ◽  
Fission Neutron

scholarly journals Regression analysis of coincidence measurements for determinating the neutron emission rate of 252Cf spontaneous fission

2018 ◽  
Vol 67 (24) ◽  
pp. 242901
Author(s):  
Li Yong-Ming ◽  
Wang Liang ◽  
Chen Xiang-Lin ◽  
Ruan Nian-Shou ◽  
Zhao De-Shan
Keyword(s):  
Regression Analysis ◽  
Spontaneous Fission ◽  
Emission Rate ◽  
Neutron Emission ◽  
Coincidence Measurements

Field Examples of Waste Assay Solutions for Curium-Contaminated Wastes

2009 ◽  
Author(s):  
Patrick M. J. Chard ◽  
Stephen Croft ◽  
Ian G. Hutchinson ◽  
Tom W. Turner ◽  
Ann Ross ◽  
...  
Keyword(s):  
Spontaneous Fission ◽  
Neutron Emission ◽  
Nuclear Data ◽  
Fission Neutron ◽  
Nuclear Material ◽  
Spent Fuel ◽  
Coincidence Counting ◽  
Plant Operations ◽  
Technical Solutions

Passive neutron coincidence counting is a mature technique for the assay of Pu in nuclear material. It is widely deployed in safeguards and waste inventory verification applications. The presence of 242Cm and 244Cm in spent fuel wastes, often poses a severe challenge owing to the relatively short spontaneous fission half-life for these isotopes and the subsequent prolific spontaneous fission neutron emission. This is a well documented problem, compounded by the fact that for most waste assay applications, neutron assay techniques are not capable of distinguishing between these Cm isotopes and the even isotopes of Pu, which are normally of interest in waste assay applications. Therefore the presence of even small quantities of these isotopes can result in gross over-estimation of the Pu inventory, if an appropriate correction is not made. Previous theoretical studies carried out recently have illustrated the potential magnitude of the problem, with reference to the fundamental nuclear data and typical isotopic compositions of wastes. Neutron multiplicity counting can, in principle, differentiate between isotopes that undergo spontaneous fission, however in practice the uncertainties in waste assay are such that this is rarely beneficial. More practical “compensation” techniques use combinations of different assay techniques (for example passive and active neutron counting) and knowledge of the actinide ratios in the waste stream fingerprint. In this paper we describe various waste assay applications as case studies. For each example we describe the nature of the challenge and show how solutions have been developed for applications where the presence of curium has caused problems. We describe the technical solutions, showing the limitations and assumptions of each. We also emphasise the role of robust Quality Assurance procedures, to ensure that the techniques are implemented reliably and with predictable outcomes. Finally, we describe the benefits that have been realised for the plant operations teams, with regard to improved measurement accuracy, avoidance of false over-estimation of the Pu inventory and subsequent improvement in plant throughput.

Calculation of Fission Neutron Spectra for Spontaneous Fission of240Pu,238Pu and242Pu

1991 ◽  
Vol 108 (1) ◽  
pp. 109-115
Author(s):  
R. L. Walsh ◽  
G. Chircu ◽  
D. G. Madland
Keyword(s):  
Spontaneous Fission ◽  
Fission Neutron ◽  
Neutron Spectra

scholarly journals Characterization of the New Vertical Neutron Camera Designed for the Low Neutron Emission Rate Plasma in Large Helical Device

2021 ◽  
Vol 16 (0) ◽  
pp. 1402039-1402039
Author(s):  
Siriyaporn SANGAROON ◽  
Kunihiro OGAWA ◽  
Mitsutaka ISOBE ◽  
Yutaka FUJIWARA ◽  
Hiroyuki YAMAGUCHI ◽  
...  
Keyword(s):  
Emission Rate ◽  
Neutron Emission

scholarly journals Prompt neutron emission in the neutron-induced fission of 239Pu and the spontaneous fission of 252Cf: an unfolding story

2018 ◽  
Author(s):  
C. Y. Wu ◽  
J. Henderson ◽  
R. A. Henderson ◽  
M. Devlin ◽  
K. J. Kelly ◽  
...  
Keyword(s):  
Spontaneous Fission ◽  
Neutron Emission ◽  
Prompt Neutron ◽  
Induced Fission

ABSOLUTE STANDARDIZATION OF RADIOACTIVE NEUTRON SOURCES: II. THE USE OF THE F19(α, n)Na22 REACTION

1959 ◽  
Vol 37 (5) ◽  
pp. 550-556 ◽  
Author(s):  
K. W. Geiger
Keyword(s):  
Nuclear Reactions ◽  
Emission Rate ◽  
Neutron Emission ◽  
National Research Council ◽  
Neutron Output ◽  
Neutron Sources ◽  
Neutron Thermalization ◽  
Γ Rays ◽  
Absolute Standardization ◽  
Good Agreement

Fluorine has only one stable isotope, F19. If neutrons are produced by the F19(α, n)Na22 reaction the neutron output can be calculated from the yield of the resulting radioactive Na22. The growth of Na22 (half-life, 2.58 years) has been measured in a neutron source consisting originally of 1.6 curies Po210 mixed with CaF2 powder. Since Na22 is a positron emitter, discrimination against γ-rays from Po210 and from nuclear reactions could be achieved by detecting the two positron annihilation quanta in coincidence. The Na22 growth has been followed over 20 months and is in agreement with the theoretical growth curve. Comparison with a calibrated Na22 source yielded a neutron emission rate of (10.70 ± 0.25) × 104 sec−1. This resulted in a neutron emission rate of (3.16 ± 0.10) × 106 sec−1 for the Ra-α-Be source of the National Research Council, in good agreement with (3.22 ± 0.05) × 106 sec−1 obtained by a neutron thermalization method.

scholarly journals Observations of poorly-known features of the 239Pu and 235U prompt fission neutron spectra

2020 ◽  
Vol 239 ◽  
pp. 05010
Author(s):  
Keegan J. Kelly ◽  
Jaime A. Gomez ◽  
John M. O'Donnell ◽  
Matthew Devlin ◽  
Robert C. Haight ◽  
...  
Keyword(s):  
Experimental Data ◽  
Neutron Spectrum ◽  
Neutron Emission ◽  
National Laboratory ◽  
Nuclear Data ◽  
Fission Neutron ◽  
Fission Neutron Spectrum ◽  
Wide Range ◽  
Prompt Fission ◽  
Prompt Fission Neutron

Prompt fission neutron spectrum (PFNS) evaluations use provide nuclear data for the PFNS across a wide range of incident and outgoing neutron energies. However, experimental data underlying the evaluation are sparse, inconsistent, and incomplete with respect to the desired incident and outgoing energy coverage. As such, evaluations sometimes predict features of the PFNS, such those relating to multi-chance fission and pre-equilibrium pre-fission neutron emission, without any experimental validation. The Chi-Nu experiment at Los Alamos National Laboratory has recently obtained high-precision results for the 239Pu and 235U PFNS which, for the first time in both cases, have shed light on multi-chance fission and pre-equilibrium contributions to the observed fission neutron spectrum. In addition to providing the first experimental data on some of these fission properties, the angular coverage of the Chi-Nu experiment allows for the extraction of angular distributions of pre-equilibrium pre-fission neutrons. PFNS results of multi-chance fission and pre-equilibrium pre-fission neutron emission are discussed in this proceedings in terms of the observed neutron spectrum and the average PFNS energies.

Pre-saddle and pre-scission neutron emission rates in heavy-ion induced fission of 16O +208Pb and 16O +209Bi systems

2019 ◽  
Vol 28 (03) ◽  
pp. 1950013
Author(s):  
Saeed Soheyli ◽  
Morteza Khalil Khalili ◽  
Ghazaaleh Ashrafi
Keyword(s):  
Emission Rate ◽  
Neutron Emission ◽  
Nonlinear Behavior ◽  
Heavy Ion ◽  
Neutron Multiplicity ◽  
Emission Rates ◽  
Reaction Systems ◽  
Initial Excitation ◽  
Induced Fission ◽  
First Time

Whereas there is a slight information on the pre-saddle neutron emission rate and neutron multiplicity, as well as it is impossible to separate the pre-saddle and saddle to scission neutron contributions experimentally, the theoretical studies of pre-saddle neutron emission rate and neutron multiplicity are of great importance. In the present work, the calculations of pre-saddle neutron multiplicity are performed using the analysis of fission fragment angular anisotropy data for [Formula: see text] and [Formula: see text] reaction systems. The obtained results show that the pre-saddle neutron multiplicity decreases by increasing the initial excitation energy and it has found to be characterized by a nonlinear behavior. Through the analysis of pre-saddle neutron multiplicity and pre-saddle transition time by means of the neutron clock method, the pre-saddle neutron emission rate is calculated for the first time. The findings of this study show that the pre-scission neutron emission rate is lower than the pre-saddle neutron emission rate.

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