### Abstract

This paper presents a new and efficient scheme to determine the optimal neutron source position in a model near-equilibrium pressurized water reactor, which is based on the OPR1000 Hanul Unit 3 Cycle 7 configuration. The proposed scheme particularly assigns importance of source positions according to the local adjoint flux distribution. In this research, detailed pin-by-pin reactor adjoint fluxes are determined by using the Monte Carlo KENO-VI code from solutions of the reactor homogeneous critical adjoint transport equations. The adjoint fluxes at each allowable source position are subsequently ranked to yield four candidate positions with the four highest adjoint fluxes. The study next simulates ex-core detector responses using the Monte Carlo MAVRIC code by assuming a neutron source is installed in one of the four candidate positions. The calculation is repeated for all positions. These detector responses are later converted into an inverse count rate ratio curve for each candidate source position. The study confirms that the optimal source position is the one with very high adjoint fluxes and detector responses, which is interestingly the original source position in the OPR1000 core, as it yields an inverse count rate ratio curve closest to the traditional 1/M line. The current work also clearly demonstrates that the proposed adjoint flux-based approach can be used to efficiently determine the optimal geometry for a neutron source and a detector in a modern pressurized water reactor core.

Original language | English |
---|---|

Pages (from-to) | 1291-1302 |

Number of pages | 12 |

Journal | Nuclear Engineering and Technology |

Volume | 48 |

Issue number | 6 |

DOIs | |

Publication status | Published - 01 Dec 2016 |

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### All Science Journal Classification (ASJC) codes

- Nuclear Energy and Engineering

### Cite this

*Nuclear Engineering and Technology*,

*48*(6), 1291-1302. https://doi.org/10.1016/j.net.2016.05.002

}

*Nuclear Engineering and Technology*, vol. 48, no. 6, pp. 1291-1302. https://doi.org/10.1016/j.net.2016.05.002

**A Study on the Optimal Position for the Secondary Neutron Source in Pressurized Water Reactors.** / Sun, Jungwon; Yahya, Mohd Syukri; Kim, Yonghee.

Research output: Contribution to journal › Article

TY - JOUR

T1 - A Study on the Optimal Position for the Secondary Neutron Source in Pressurized Water Reactors

AU - Sun, Jungwon

AU - Yahya, Mohd Syukri

AU - Kim, Yonghee

PY - 2016/12/1

Y1 - 2016/12/1

N2 - This paper presents a new and efficient scheme to determine the optimal neutron source position in a model near-equilibrium pressurized water reactor, which is based on the OPR1000 Hanul Unit 3 Cycle 7 configuration. The proposed scheme particularly assigns importance of source positions according to the local adjoint flux distribution. In this research, detailed pin-by-pin reactor adjoint fluxes are determined by using the Monte Carlo KENO-VI code from solutions of the reactor homogeneous critical adjoint transport equations. The adjoint fluxes at each allowable source position are subsequently ranked to yield four candidate positions with the four highest adjoint fluxes. The study next simulates ex-core detector responses using the Monte Carlo MAVRIC code by assuming a neutron source is installed in one of the four candidate positions. The calculation is repeated for all positions. These detector responses are later converted into an inverse count rate ratio curve for each candidate source position. The study confirms that the optimal source position is the one with very high adjoint fluxes and detector responses, which is interestingly the original source position in the OPR1000 core, as it yields an inverse count rate ratio curve closest to the traditional 1/M line. The current work also clearly demonstrates that the proposed adjoint flux-based approach can be used to efficiently determine the optimal geometry for a neutron source and a detector in a modern pressurized water reactor core.

AB - This paper presents a new and efficient scheme to determine the optimal neutron source position in a model near-equilibrium pressurized water reactor, which is based on the OPR1000 Hanul Unit 3 Cycle 7 configuration. The proposed scheme particularly assigns importance of source positions according to the local adjoint flux distribution. In this research, detailed pin-by-pin reactor adjoint fluxes are determined by using the Monte Carlo KENO-VI code from solutions of the reactor homogeneous critical adjoint transport equations. The adjoint fluxes at each allowable source position are subsequently ranked to yield four candidate positions with the four highest adjoint fluxes. The study next simulates ex-core detector responses using the Monte Carlo MAVRIC code by assuming a neutron source is installed in one of the four candidate positions. The calculation is repeated for all positions. These detector responses are later converted into an inverse count rate ratio curve for each candidate source position. The study confirms that the optimal source position is the one with very high adjoint fluxes and detector responses, which is interestingly the original source position in the OPR1000 core, as it yields an inverse count rate ratio curve closest to the traditional 1/M line. The current work also clearly demonstrates that the proposed adjoint flux-based approach can be used to efficiently determine the optimal geometry for a neutron source and a detector in a modern pressurized water reactor core.

UR - http://www.scopus.com/inward/record.url?scp=84979649244&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84979649244&partnerID=8YFLogxK

U2 - 10.1016/j.net.2016.05.002

DO - 10.1016/j.net.2016.05.002

M3 - Article

AN - SCOPUS:84979649244

VL - 48

SP - 1291

EP - 1302

JO - Nuclear Engineering and Technology

JF - Nuclear Engineering and Technology

SN - 1738-5733

IS - 6

ER -