scholarly journals Parameter Optimization and Sensitivity Studies of Spontaneous Fission with FREYA

2020 ◽  
Vol 239 ◽  
pp. 05003
Author(s):  
R. Vogt ◽  
J. Randrup ◽  
P. Talou ◽  
J. T. Van Dyke ◽  
L. A. Bernstein
Keyword(s):  
Spontaneous Fission ◽  
Fission Products ◽  
Event Analysis ◽  
Fission Reaction ◽  
Fission Event ◽  
Large Samples ◽  
Yield Functions ◽  
Sensitivity Studies ◽  
Average Neutron ◽  
Kinematic Information

For many years, the state of the art for simulating fission in transport codes amounted to sampling from average distributions. However, such "average" fission models have limited capabilities. Energy is not explicitly conserved and no correlations are available because all particles are emitted independently. However, in a true fission event, the emitted particles are correlated. Recently, Monte Carlo codes generating complete fission events have been developed, thus allowing the use of event-by-event analysis techniques. Such techniques are particularly useful because the complete kinematic information is available for the fission products and the emitted neutrons and photons. It is therefore possible to extract any desired observables, including correlations. The fast event-by-event fission code FREYA (Fission Reaction Event Yield Algorithm) generates large samples of complete fission events, employing only a few physics-based parameters. A recent optimization of these parameters for the isotopes in FREYA that undergo spontaneous fission is described and results are presented. The sensitivity of neutron observables in FREYA to the input yield functions is also discussed and the correlation between the average neutron multiplicity and fragment total kinetic energy is quantified.

Yields of rare earth fission products in the spontaneous fission of californium-252

1985 ◽  
Vol 91 (2) ◽  
pp. 291-296
Author(s):  
B. S. Tomar ◽  
H. Naik ◽  
A. Ramaswamy ◽  
Satya Prakash
Keyword(s):  
Rare Earth ◽  
Spontaneous Fission ◽  
Fission Products

Depletion calculation of subcritical system with consideration of spontaneous fission reaction

2021 ◽  
pp. 1-7
Author(s):  
Eka Sapta Riyana ◽  
Keisuke Okumura ◽  
Masahiro Sakamoto ◽  
Taichi Matsumura ◽  
Kenichi Terashima
Keyword(s):  
Spontaneous Fission ◽  
Fission Reaction ◽  
Subcritical System

STUDIES OF SUPERHEAVY ELEMENTS AT SHIP

2007 ◽  
Vol 16 (04) ◽  
pp. 937-947
Author(s):  
S. HOFMANN ◽  
D. ACKERMANN ◽  
S. ANTALIC ◽  
H. G. BURKHARD ◽  
V. F. COMAS ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Experimental Work ◽  
Spontaneous Fission ◽  
Measured Data ◽  
Superheavy Elements ◽  
Fission Event

An overview of present experimental investigation of superheavy elements is given. The data are compared with theoretical descriptions. Results are reported from an experiment to confirm production of element 112 isotopes in irradiation of 238 UF 4 with 48 Ca . One spontaneous fission event was measured, which agrees with three events of previously measured data which had been assigned to the decay of 283112. However, more experimental work is needed in order to obtain an independent and unambiguous confirmation of previous results.

scholarly journals Employing FREYA for fission product yield evaluations

2020 ◽  
Vol 242 ◽  
pp. 03002
Author(s):  
R. Vogt ◽  
J. Randrup ◽  
N. Vassh ◽  
T. Sprouse ◽  
R. Surman
Keyword(s):  
Fission Product ◽  
Product Yield ◽  
Fission Yield ◽  
Fission Reaction ◽  
Product Yields ◽  
Large Samples ◽  
Reaction Event ◽  
Fission Product Yields ◽  
The Future ◽  
Fission Product Yield

The fast event-by-event fission code FREYA (Fission Reaction Event Yield Algorithm) generates large samples of complete fission events while employing only a few physics-based parameters. Not only is FREYA fast, it is also flexible, able to employ a variety of input formats to test the implications of various fission yield evaluations on neutron and photon observables. We describe how FREYA was applied to the neutron-rich nuclei needed for r-process nucleosynthesis calculations as an example of this flexibility. Finally, we discuss how we plan to make use of this flexibility to extend FREYA to calculations of cumulative fission product yields to aid evaluations of these yields in the future.

Determination of the plutonium mass in containers with plutonium dioxide according to the γ radiation from spontaneous-fission products

Atomic Energy ◽  
2010 ◽  
Vol 108 (1) ◽  
pp. 46-52
Author(s):  
A. V. Bushuev ◽  
A. F. Kozhin ◽  
T. B. Aleeva ◽  
V. N. Zubarev ◽  
A. F. Myrzin ◽  
...  
Keyword(s):  
Spontaneous Fission ◽  
Fission Products ◽  
Plutonium Dioxide ◽  
Γ Radiation

FISSION OF EXCITED HEAVY NUCLEI

1958 ◽  
Vol 36 (12) ◽  
pp. 1707-1719 ◽  
Author(s):  
B. D. Pate
Keyword(s):  
Fission Products ◽  
Nuclear Fission ◽  
Low Energy ◽  
Heavy Nuclei ◽  
Fission Process ◽  
Distribution Mode ◽  
Charge Displacement ◽  
Comparison Of The Results ◽  
Average Neutron ◽  
Mev Protons

The results of published calculations on the prompt nuclear cascade and nuclear evaporation processes are combined with some assumptions regarding the nuclear fission process and fission widths to calculate the average neutron-to-proton ratios of fission products from Th + 8-Mev protons, Th + 87-Mev protons, and U + 450-Mev protons. Comparison of the results with experimental data indicates that the fission charge distribution mode characterized by the equal charge displacement hypothesis, hitherto considered a low energy phenomenon, persists in uranium and thorium up to the highest energy studied. There is also some evidence that fission occurs in excited heavy nuclei before complete de-excitation by particle emission, in agreement with other experimental work.

scholarly journals DEVELOPMENT AND EXPERIMENTAL VALIDATION OF RESPONSE MODELLING FOR TIME-OF-FLIGHT NEUTRON DETECTION AND IMAGING SYSTEMS

2021 ◽  
Vol 247 ◽  
pp. 16001
Author(s):  
Steven C. Bradnam ◽  
Vytautas Astromskas ◽  
Zamir Ghani ◽  
Mark R. Gilbert ◽  
Malcolm J. Joyce ◽  
...  
Keyword(s):  
Spontaneous Fission ◽  
Gamma Ray ◽  
Detection System ◽  
Time Of Flight ◽  
Neutron Detection ◽  
Imaging Systems ◽  
Water Tank ◽  
Fission Event ◽  
True Source ◽  
Response Modelling

The application and feasibility of a time-of-flight neutron detection system is explored for sources with time correlated gamma-ray and neutron emissions, such as the spontaneous fission emitter, Cf-252. For the emission of multiple gamma rays and neutrons from a single spontaneous fission event, a near instantaneous gamma-ray detection followed by a later neutron detection on a multi-detector array allows for an associated time-of-flight to be determined for a neutron arising from that event. Using a suite of purpose developed analysis tools, Monte-Carlo simulation and experimental data are compared for the Cf-252 water tank source facility at Lancaster University. Applying a bespoke time-of-flight imaging algorithm, vector-based optimisation (VBO), the true source location is determined within 21 cm by this approach.

ABSOLUTE YIELDS OF THE XENON AND KRYPTON ISOTOPES IN U238 SPONTANEOUS FISSION

1960 ◽  
Vol 38 (1) ◽  
pp. 1-9 ◽  
Author(s):  
B. G. Young ◽  
H. G. Thode
Keyword(s):  
Fission Product ◽  
Spontaneous Fission ◽  
Fission Products ◽  
Inert Gases ◽  
Geological Time ◽  
Neutron Fission ◽  
Fission Gas ◽  
Thermal Neutron Fission ◽  
Induced Fission ◽  
The Absolute

The absolute abundances of the isotopes of fission-product xenon and krypton in six uranium minerals have been determined mass spectrometrically using the isotope dilution technique. The fission products were resolved into a U238 spontaneous fission component, a U235 neutron-induced fission component, and a U238 neutron-induced fission component. Internal consistency in the analysis was achieved only when the Xe129 yield used for the U235 thermal neutron fission component was 20% lower than that reported by Purkayastha and Martin at I129. This discrepancy in the mass 129 chain yield measured at I129 and at Xe129 has not been resolved.Only one of the six minerals, Cinch Lake pitchblende, retained essentially all of its fission product inert gases throughout geological time. Inert gas losses from the remaining five minerals ranged from 20% to 75%. The absolute yields of the stable xenon and krypton fission products in U238 spontaneous fission were determined from an analysis of the inert gases from the Cinch Lake mineral. This analysis showed that 95.9% of the fission gas in this case resulted from the spontaneous fission and only 4.1% from neutron-induced fission.

scholarly journals Reactions of fission products from a 252Cf source with NO and mixtures of NO and CO in an inert gas

2019 ◽  
Vol 107 (7) ◽  
pp. 555-560 ◽  
Author(s):  
Heinz W. Gäggeler ◽  
Ilya Usoltsev ◽  
Robert Eichler
Keyword(s):  
Spontaneous Fission ◽  
Fission Products ◽  
Inert Gases ◽  
Inert Gas ◽  
Efficient Production ◽  
Carbonyl Complexes ◽  
No Formation ◽  
252Cf Source ◽  
Transport Path ◽  
Accident Scenarios

Abstract Fission products recoiling from a 252Cf spontaneous fission source were stopped in various mixtures of inert gases containing CO and NO. For the elements of the transisition metal series Mo, Tc, Ru, and Rh previous observations of pure carbonyl complexes were reproduced. However, no formation of volatile mixed nitrosyl-carbonyl complexes or pure nitrosyl complexes for these elements have been observed. Instead, efficient production of volatile nitrosyl compounds for single iodine atoms, presumably nitrosyl iodide, NOI, was detected. This observation is of interest as potential transport path for iodine in nuclear accident scenarios and as a model for radiochemistry with the recently discovered heaviest halogen tennessine (Z=117).

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