Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Event-by-event study of prompt neutrons from Pu 239 (n,f)

Journal Article · · Physical Review. C. Nuclear Physics
 [1];  [2];  [3];  [3]
  1. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Univ. of California, Davis, CA (United States)
  2. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
  3. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
+ Show Author Affiliations
Employing a recently developed Monte-Carlo model, we study the fission of 240Pu induced by neutrons with energies from thermal to just below the threshold for second chance fission. Current measurements of the mean number of prompt neutrons emitted in fission, together with less accurate measurements of the neutron energy spectra, place remarkably fine constraints on predictions of microscopic calculations. In particular, the total excitation energy of the nascent fragments must be specified to within 1MeV to avoid disagreement with measurements of the mean neutron multiplicity. Here, the combination of the Monte-Carlo fission model with a statistical likelihood analysis also presents a powerful tool for the evaluation of fission neutron data. Of particular importance is the fission spectrum, which plays a key role in determining reactor criticality. We show that our approach can be used to develop an estimate of the fission spectrum with uncertainties several times smaller than current experimental uncertainties for outgoing neutron energies of less than 2 MeV.
Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Organization:
National Science Foundation (NSF); USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
Grant/Contract Number:
AC02-05CH11231; AC52-07NA27344; W-7405-ENG-48
OSTI ID:
966914
Report Number(s):
LLNL--JRNL-415141
Journal Information:
Physical Review. C. Nuclear Physics, Journal Name: Physical Review. C. Nuclear Physics Journal Issue: 4 Vol. 80; ISSN 0556-2813
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English

References (57)

Dependence of $$\bar v$$ on neutron energies up to 5 MeV for233U,238U, and239Pu journal September 1975
Secondary neutron spectra in235U and239Pu fission by 0.1 MeV neutrons journal February 1975
�ber den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle journal January 1939
Prompt v in neutron-induced fission of 239Pu and 241Pu journal January 1968
The energy dependence of for 233U, 235U and 239Pu below 5·0 MeV journal August 1971
Prompt neutrons from fission journal October 1963
Neutron emission from U233, U235 and Pu239 fission fragments journal September 1965
Nuclear scission journal December 1990
Fission fragment K x-ray emission and nuclear charge distribution for thermal neutron fission of 233U, 235U, 239Pu and spontaneous fission of 252Cf journal December 1971
Microscopic analysis of collective dynamics in low energy fission journal October 1984
Fission mode fluctuations in the resonances of 235U(n,f) journal January 1989
Fluctuations in nuclear dynamics From transport theory to dynamical simulation journal July 1991
Prompt fission neutron energy spectra induced by fast neutrons journal August 1995
The 1995 update to the atomic mass evaluation journal December 1995
ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology journal December 2006
Nuclear mass formula with shell energies calculated by a new method journal July 2000
Multiplicity and energy of neutrons from 235U(nth,f) fission fragments journal March 1998
Investigation of the fission fragment properties of the reaction 238U(n,f) at incident neutron energies up to 5.8 MeV journal January 2000
Disintegration of Uranium by Neutrons: a New Type of Nuclear Reaction journal February 1939
Nuclear fission modes and fragment mass asymmetries in a five-dimensional deformation space journal February 2001
Distribution of Prompt Neutron Emission Probability for Fission Fragments in Spontaneous Fission of 252Cf and 244,248Cm conference January 2005
Nuclear Fission journal August 1974
Measurement of Fragment Mass Dependent Kinetic Energy and Neutron Multiplicity for Thermal Neutron Induced Fission of Plutonium-239 journal May 1995
Simultaneous Measurement of Prompt Neutrons and Fission Fragments for 239 Pu( n th ,f ) journal November 2000
Statistics and Nuclear Reactions journal August 1937
The Mechanism of Nuclear Fission journal September 1939
Comparison of the energy and mass characteristics of the Pu 239 ( n th , f ) and the Pu 240 (sf) fragments journal July 1984
Sawtooth curve of neutron multiplicity journal October 1985
Microscopic approach of fission dynamics applied to fragment kinetic energy and mass distributions in U 238 journal February 2005
Monte Carlo approach to sequential neutron emission from fission fragments journal August 2005
Structure properties of Th 226 and Fm 256 , 258 , 260 fission fragments: Mean-field analysis with the Gogny force journal January 2008
Heavy-element fission barriers journal June 2009
Calculation of fission observables through event-by-event simulation journal August 2009
Evaluation of p for 239 Pu: Impact for Applications of the Fluctuations at Low Energy journal August 1988
Nuclear Ground-State Masses and Deformations text January 1993
Nuclear Ground-State Masses and Deformations journal March 1995
Dependence of $$\bar v$$ on neutron energies up to 5 MeV for233U,238U, and239Pu journal September 1975
Secondary neutron spectra in235U and239Pu fission by 0.1 MeV neutrons journal February 1975
�ber den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle journal January 1939
Nuclear scission journal December 1990
Fluctuations in nuclear dynamics From transport theory to dynamical simulation journal July 1991
Prompt fission neutron energy spectra induced by fast neutrons journal August 1995
Nuclear mass formula with shell energies calculated by a new method journal July 2000
Multiplicity and energy of neutrons from 235U(nth,f) fission fragments journal March 1998
Investigation of the fission fragment properties of the reaction 238U(n,f) at incident neutron energies up to 5.8 MeV journal January 2000
Statistics and Nuclear Reactions journal August 1937
The Mechanism of Nuclear Fission journal September 1939
Comparison of the energy and mass characteristics of the Pu 239 ( n th , f ) and the Pu 240 (sf) fragments journal July 1984
Sawtooth curve of neutron multiplicity journal October 1985
Microscopic approach of fission dynamics applied to fragment kinetic energy and mass distributions in U 238 journal February 2005
Monte Carlo approach to sequential neutron emission from fission fragments journal August 2005
Structure properties of Th 226 and Fm 256 , 258 , 260 fission fragments: Mean-field analysis with the Gogny force journal January 2008
Heavy-element fission barriers journal June 2009
Calculation of fission observables through event-by-event simulation journal August 2009
Evaluation of p for 239 Pu: Impact for Applications of the Fluctuations at Low Energy journal August 1988
Measurement of Fragment Mass Dependent Kinetic Energy and Neutron Multiplicity for Thermal Neutron Induced Fission of Plutonium-239. journal January 1995
Simultaneous Measurement of Prompt Neutrons and Fission Fragments for 239Pu(nth, f). journal January 2000

Figures / Tables (26)

FIG. 4(p. 8)figure FIG. 4
FIG. 10(p. 13)figure FIG. 10
Table IV(p. 12)table Table IV
FIG. 15(p. 15)figure FIG. 15
FIG. 6(p. 9)figure FIG. 6
FIG. 8(p. 9)figure FIG. 8
Table V(p. 12)table Table V
FIG. 7(p. 9)figure FIG. 7
FIG. 2(p. 6)figure FIG. 2
FIG. 3(p. 6)figure FIG. 3
FIG. 14(p. 15)figure FIG. 14
FIG. 18(p. 16)figure FIG. 18
FIG. 1(p. 4)figure FIG. 1
FIG. 5(p. 8)figure FIG. 5
FIG. 12(p. 14)figure FIG. 12
FIG. 20(p. 17)figure FIG. 20
FIG. 13(p. 14)figure FIG. 13
FIG. 19(p. 17)figure FIG. 19
TABLE VI(p. 17)table TABLE VI
Table II(p. 7)table Table II
TABLE I(p. 5)table TABLE I
Table III(p. 11)table Table III
FIG. 9(p. 10)figure FIG. 9
FIG. 11(p. 14)figure FIG. 11
FIG. 17(p. 16)figure FIG. 17
FIG. 16(p. 15)figure FIG. 16

Similar Records

Event-by-Event Study of Prompt Neutrons from 239Pu
Conference · Mon Oct 26 00:00:00 EDT 2009 · OSTI ID:972127
First Direct Measurement Constraining the Ar34(α,p)K37 Reaction Cross Section for Mixed Hydrogen and Helium Burning in Accreting Neutron Stars
Journal Article · Sun May 21 20:00:00 EDT 2023 · Physical Review Letters · OSTI ID:1976058

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CRITICALITY
ENERGY SPECTRA
EVALUATION
EXCITATION
FISSION
FISSION NEUTRONS
MULTIPLICITY
NEUTRONS
Nuclear Criticality Safety Program (NCSP)
PROMPT NEUTRONS