# Description of induced nuclear fission with Skyrme energy functionals. II. Finite temperature effects

## Abstract

Understanding the mechanisms of induced nuclear fission for a broad range of neutron energies could help resolve fundamental science issues, such as the formation of elements in the universe, but could have also a large impact on societal applications in energy production or nuclear waste management. The goal of this paper is to set up the foundations of a microscopic theory to study the static aspects of induced fission as a function of the excitation energy of the incident neutron, from thermal to fast neutrons. To account for the high excitation energy of the compound nucleus, we employ a statistical approach based on finite temperature nuclear density functional theory with Skyrme energy densities, which we benchmark on the ^{239}Pu ($n ,f$) reaction. We compute the evolution of the least-energy fission pathway across multidimensional potential energy surfaces with up to five collective variables as a function of the nuclear temperature and predict the evolution of both the inner and the outer fission barriers as a function of the excitation energy of the compound nucleus. We show that the coupling to the continuum induced by the finite temperature is negligible in the range of neutron energies relevant for many applications of neutron-inducedmore »

- Authors:

- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of Leeds, Leeds (United Kingdom)

- Publication Date:

- Research Org.:
- Oak Ridge National Laboratory, Oak Ridge Leadership Computing Facility (OLCF); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

- Sponsoring Org.:
- USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)

- OSTI Identifier:
- 1565370

- Alternate Identifier(s):
- OSTI ID: 1180645

- Grant/Contract Number:
- AC52-07NA27344

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physical Review. C, Nuclear Physics

- Additional Journal Information:
- Journal Volume: 91; Journal Issue: 3; Journal ID: ISSN 0556-2813

- Publisher:
- American Physical Society (APS)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Physics

### Citation Formats

```
Schunck, N., Duke, D., and Carr, H. Description of induced nuclear fission with Skyrme energy functionals. II. Finite temperature effects. United States: N. p., 2015.
Web. doi:10.1103/physrevc.91.034327.
```

```
Schunck, N., Duke, D., & Carr, H. Description of induced nuclear fission with Skyrme energy functionals. II. Finite temperature effects. United States. doi:10.1103/physrevc.91.034327.
```

```
Schunck, N., Duke, D., and Carr, H. Wed .
"Description of induced nuclear fission with Skyrme energy functionals. II. Finite temperature effects". United States. doi:10.1103/physrevc.91.034327. https://www.osti.gov/servlets/purl/1565370.
```

```
@article{osti_1565370,
```

title = {Description of induced nuclear fission with Skyrme energy functionals. II. Finite temperature effects},

author = {Schunck, N. and Duke, D. and Carr, H.},

abstractNote = {Understanding the mechanisms of induced nuclear fission for a broad range of neutron energies could help resolve fundamental science issues, such as the formation of elements in the universe, but could have also a large impact on societal applications in energy production or nuclear waste management. The goal of this paper is to set up the foundations of a microscopic theory to study the static aspects of induced fission as a function of the excitation energy of the incident neutron, from thermal to fast neutrons. To account for the high excitation energy of the compound nucleus, we employ a statistical approach based on finite temperature nuclear density functional theory with Skyrme energy densities, which we benchmark on the 239Pu ($n ,f$) reaction. We compute the evolution of the least-energy fission pathway across multidimensional potential energy surfaces with up to five collective variables as a function of the nuclear temperature and predict the evolution of both the inner and the outer fission barriers as a function of the excitation energy of the compound nucleus. We show that the coupling to the continuum induced by the finite temperature is negligible in the range of neutron energies relevant for many applications of neutron-induced fission. We prove that the concept of quantum localization introduced recently can be extended to T > 0 , and we apply the method to study the interaction energy and total kinetic energy of fission fragments as a function of the temperature for the most probable fission. While large uncertainties in theoretical modeling remain, we conclude that a finite temperature nuclear density functional may provide a useful framework to obtain accurate predictions of fission fragment properties.},

doi = {10.1103/physrevc.91.034327},

journal = {Physical Review. C, Nuclear Physics},

number = 3,

volume = 91,

place = {United States},

year = {2015},

month = {3}

}

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