scholarly journals Summation Calculations for Reactor Antineutrino Spectra, Decay Heat and Delayed Neutron Fractions Involving New TAGS Data and Evaluated Databases

2019 ◽  
Vol 211 ◽  
pp. 01001
Author(s):  
M. Estienne ◽  
M. Fallot ◽  
L. Giot ◽  
V. Guadilla-Gomez ◽  
L. Le Meur ◽  
...  
Keyword(s):  
Fission Product ◽  
Neutron Emission ◽  
Fission Products ◽  
Nuclear Data ◽  
Delayed Neutron ◽  
Data Bases ◽  
Decay Data ◽  
Decay Heat ◽  
Reactor Antineutrino ◽  
Decay Properties

Three observables of interest for present and future reactors depend on the β decay properties of the fission products: antineutrinos from reactors, the reactor decay heat and delayed neutron emission. In these proceedings, we present new results from summation calculations of the first two quantities quoted above, performed with evolved independent yields coupled with fission product decay data, from various nuclear data bases or models. New TAGS results from the latest experiment of the TAGS collaboration at the JYFL facility of Jyväskylä will be displayed as well as their impact on the antineutrino spectra and the decay heat associated to fission pulses of the main actinides.

scholarly journals Recent advances in beta decay measurements

2018 ◽  
Vol 4 ◽  
pp. 24
Author(s):  
Magali Estienne ◽  
Muriel Fallot ◽  
Lydie Giot ◽  
Loïc Le Meur ◽  
Amanda Porta
Keyword(s):  
Neutron Emission ◽  
Uncertainty Propagation ◽  
Fission Products ◽  
Nuclear Data ◽  
Summation Method ◽  
Experimental Simulation ◽  
Decay Data ◽  
Decay Heat ◽  
Systematic Effects ◽  
Working Groups

Three observables of interest for present and future reactors depend on the β decay data of the fission products: the reactor decay heat, antineutrinos from reactors and delayed neutron emission. Concerning the decay heat, significant discrepancies still exist between summation calculations in − their two main ingredients: the decay data and the fission yields − performed using the most recent evaluated databases available. It has been recently shown that the associated uncertainties are dominated by the ones on the decay data. But the results subtantially differ taking into account or not the correlations between the fission products. So far the uncertainty propagation does not include as well systematic effects on nuclear data such as the Pandemonium effect which impacts a large number of nuclei contributing to the decay heat. The list of nuclei deserving new TAGS measurements has been updated recently in the frame of IAEA working groups. The issues listed above impact in the same way the predicted energy spectra of the antineutrinos from reactors computed with the summation method, the interest of which has been recently reinforced by the Daya Bay latest publication. Nuclear data should definitely contribute to refine and better control these calculations. Lastly, a lot of nuclear data related to delayed neutrons are missing in nuclear databases. Despite the progresses already done these last years with new measurements now requiring to be included in evaluated databases, the experimental efforts which still need to be done are significant. These different issues will be addressed here before to comment on recent experimental results and on their impacts on the quoted observables. Some perspectives will also be presented. Solving the issues listed above will require to bring together experimental, simulation, evaluation and theoretical activities.

scholarly journals Separation of Lanthanide Isotopes from Mixed Fission Product Samples

Separations ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 104
Author(s):  
Leah M. Arrigo ◽  
Jun Jiang ◽  
Zachary S. Finch ◽  
James M. Bowen ◽  
Staci M. Herman ◽  
...  
Keyword(s):  
Fission Product ◽  
Fission Products ◽  
Nuclear Data ◽  
Product Analysis ◽  
Data Production ◽  
Thermal Irradiation ◽  
Nuclear Events ◽  
Lanthanide Separation ◽  
Enriched Uranium ◽  
Fission Yields

The measurement of radioactive fission products from nuclear events has important implications for nuclear data production, environmental monitoring, and nuclear forensics. In a previous paper, the authors reported the optimization of an intra-group lanthanide separation using LN extraction resin from Eichrom Technologies®, Inc. and a nitric acid gradient. In this work, the method was demonstrated for the separation and quantification of multiple short-lived fission product lanthanide isotopes from a fission product sample produced from the thermal irradiation of highly enriched uranium. The separations were performed in parallel in quadruplicate with reproducible results and high decontamination factors for 153Sm, 156Eu, and 161Tb. Based on the results obtained here, the fission yields for 144Ce, 153Sm, 156Eu, and 161Tb are consistent with published fission yields. This work demonstrates the effectiveness of the separations for the intended application of short-lived lanthanide fission product analysis requiring high decontamination factors.

High Resolution Measurements of Delayed Neutron Emission Spectra from Fission Products

1983 ◽  
pp. 261-264 ◽  
Author(s):  
T.-R. Yeh ◽  
D. D. Clark ◽  
G. Scharff-Goldhaber ◽  
R. E. Chrien ◽  
L.-J. Yuan ◽  
...  
Keyword(s):  
High Resolution ◽  
Neutron Emission ◽  
Fission Products ◽  
Emission Spectra ◽  
Delayed Neutron ◽  
Neutron Emission Spectra

scholarly journals Prompt and Delayed Neutron Emissions and Fission Product Yield Calculations with Hauser-Feshbach Statistical Decay Theory and Summation Calculation Method

2019 ◽  
Vol 211 ◽  
pp. 04005 ◽  
Author(s):  
Shin Okumura ◽  
Toshihiko Kawano ◽  
Satoshi Chiba
Keyword(s):  
Fission Product ◽  
Fission Fragment ◽  
Neutron Emission ◽  
Product Yield ◽  
Prompt Neutron ◽  
Delayed Neutron ◽  
Statistical Decay ◽  
Fission Product Yield ◽  
Neutron Multiplicities ◽  
D Model

We demonstrate the neutron emission and fission product yield calculations using the Hauser–Feshbach Fission Fragment Decay (HF3D) model and β decay. The HF3D model calculates the statistical decay of more than 500 primary fission fragment pairs formed by the neutron induced fission of 235U. In order to calculate the prompt neutron and photon emissions, the primary fission fragment distributions, i.e. mass, charge, excitation energy, spin and parity are deterministically generated and numerically integrated for all fission fragments. The calculated prompt neutron multiplicities, independent fission product yield are fully consistent each other. We combine the β-decay and the summation calculations with the HF3D model calculation to obtain the cumulative fission product yield, decay heat and delayed neutron yield. The calculated fission observables are compared with available experimental data.

scholarly journals Uncertainty quantification works relevant to fission yields and decay data

2018 ◽  
Vol 4 ◽  
pp. 43
Author(s):  
Go Chiba ◽  
Shunsuke Nihira
Keyword(s):  
Perturbation Theory ◽  
Uncertainty Quantification ◽  
Nuclear Data ◽  
Code System ◽  
Reactor Physics ◽  
Delayed Neutrons ◽  
Decay Data ◽  
Decay Heat ◽  
Numerical Tools ◽  
Fission Yields

In the present paper, firstly, we review our previous works on uncertainty quantification (UQ) of reactor physics parameters. This consists of (1) development of numerical tools based on the depletion perturbation theory (DPT), (2) linearity of reactor physics parameters to nuclear data, (3) UQ of decay heat and its reduction, and (4) correlation between decay heat and β-delayed neutrons emission. Secondly, we show results of extensive calculations about UQ on decay heat with several different numerical conditions by the DPT-based capability of a reactor physics code system CBZ.

scholarly journals FISSION-PRODUCT RELEASES FROM A PHWR TERMINAL DEBRIS BED

2016 ◽  
Vol 5 (1) ◽  
pp. 95-105 ◽  
Author(s):  
M.J. Brown ◽  
D.G. Bailey
Keyword(s):  
Fission Product ◽  
Heavy Water ◽  
Fission Products ◽  
Severe Accident ◽  
Water Reactor ◽  
Decay Heat ◽  
The Core ◽  
Heavy Water Reactor ◽  
Release Model ◽  
Tank Water

During an unmitigated severe accident in a pressurized heavy water reactor (PHWR) with horizontal fuel channels, the core may disassemble and relocate to the bottom of the calandria vessel. The resulting heterogeneous in-vessel terminal debris bed (TDB) would likely be quenched by any remaining moderator, and some of the decay heat would be conducted through the calandria vessel shell to the surrounding reactor vault or shield tank water. As the moderator boiled off, the solid debris bed would transform into a more homogeneous molten corium pool located between top and bottom crusts. Until recently, the severe accident code MAAP-CANDU assumed that unreleased volatile and semi-volatile fission products remained in the TDB until after calandria vessel failure, due to low diffusivity through the top crust and the lack of gases or steam to flush released fission products from the debris. However, national and international experimental results indicate this assumption is unlikely; instead, high- and medium-volatility fission products would be released from a molten debris pool, and their volatility and transport should be taken into account in TDB modelling. The resulting change in the distribution of fission products within the reactor and containment, and the associated decay heat, can have significant effects upon the progression of the accident and fission-product releases to the environment. This article describes a postulated PHWR severe accident progression to generate a TDB and the effects of fission-product releases from the terminal debris, using the simple release model in the MAAP-CANDU severe accident code. It also provides insights from various experimental programs related to fission-product releases from core debris, and their applicability to the MAAP-CANDU TDB model.

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