### Abstract

simulations in a hot-cell geometry, which consists of both heavily shielded structures and large volumes of empty space. The results show that the weight-window mesh adaptation obeys the constraints imposed by the problem geometry, and that the variance reduction scheme provides significant improvement in computational performance compared to an analog Monte Carlo simulation.

Original language | English |
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Title of host publication | International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2019 |

Publisher | American Nuclear Society ANS |

Pages | 85-95 |

Number of pages | 11 |

ISBN (Print) | 978-0-89448-769-9 |

Publication status | Published - 2019 |

MoE publication type | A4 Article in a conference publication |

Event | International Conference on Mathematics and Computational Methods applied to Nuclear Science and Engineering - Portland, United States Duration: 25 Aug 2019 → 29 Aug 2019 |

### Conference

Conference | International Conference on Mathematics and Computational Methods applied to Nuclear Science and Engineering |
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Country | United States |

City | Portland |

Period | 25/08/19 → 29/08/19 |

### Fingerprint

### Keywords

- Serpent
- Monte Carlo
- Global Variance Reduction
- Weight-windows
- Radiation Shielding

### Cite this

*International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2019*(pp. 85-95). American Nuclear Society ANS.

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*International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2019.*American Nuclear Society ANS, pp. 85-95, International Conference on Mathematics and Computational Methods applied to Nuclear Science and Engineering, Portland, United States, 25/08/19.

**Global variance reduction scheme with self-adaptive weight-window mesh in the Serpent 2 Monte Carlo Code.** / Leppänen, Jaakko; Jokipii, Mika.

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review

TY - GEN

T1 - Global variance reduction scheme with self-adaptive weight-window mesh in the Serpent 2 Monte Carlo Code

AU - Leppänen, Jaakko

AU - Jokipii, Mika

PY - 2019

Y1 - 2019

N2 - A global variance reduction (GVR) scheme with self-adaptive weight-window mesh was recently implemented in the Serpent 2 Monte Carlo code. Importances used to define the weight-window boundaries are obtained from a built-in deterministic solver, which applies the response matrix method to the adjoint transport problem. The mesh is based on an octree-type data structure, which can be refined by recursively dividing the mesh cells. The split criteria take into account the local density of the medium and the gradient of the importance distribution. The methodology is demonstrated by photon transportsimulations in a hot-cell geometry, which consists of both heavily shielded structures and large volumes of empty space. The results show that the weight-window mesh adaptation obeys the constraints imposed by the problem geometry, and that the variance reduction scheme provides significant improvement in computational performance compared to an analog Monte Carlo simulation.

AB - A global variance reduction (GVR) scheme with self-adaptive weight-window mesh was recently implemented in the Serpent 2 Monte Carlo code. Importances used to define the weight-window boundaries are obtained from a built-in deterministic solver, which applies the response matrix method to the adjoint transport problem. The mesh is based on an octree-type data structure, which can be refined by recursively dividing the mesh cells. The split criteria take into account the local density of the medium and the gradient of the importance distribution. The methodology is demonstrated by photon transportsimulations in a hot-cell geometry, which consists of both heavily shielded structures and large volumes of empty space. The results show that the weight-window mesh adaptation obeys the constraints imposed by the problem geometry, and that the variance reduction scheme provides significant improvement in computational performance compared to an analog Monte Carlo simulation.

KW - Serpent

KW - Monte Carlo

KW - Global Variance Reduction

KW - Weight-windows

KW - Radiation Shielding

UR - http://www.ans.org/store/item-700432/

UR - http://www.scopus.com/inward/record.url?scp=85075354629&partnerID=8YFLogxK

M3 - Conference article in proceedings

SN - 978-0-89448-769-9

SP - 85

EP - 95

BT - International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2019

PB - American Nuclear Society ANS

ER -