title: An investigation of reactivity effect due to inadvertent filling of the irradiation channels with water in NIRR-1 Nigeria Research Reactor-1.
abstract: Investigation of reactivity variation due to flooding of the irradiation channels of Nigeria Research Reactor (NIRR-1) a low power miniature neutron source reactor (MNSR) located at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria Nigeria using the MCNP code for High Enrich Uranium (HEU) and Low Enrich Uranium (LEU) core has been simulated in this present study. In this work, the excess reactivity worth of flooding HEU core for 1 inner, 2 inner, 3 inner, 4 inner and all inner are 0.318mk, 0.577mk, 0.318mk, 1.204mk and 1.503mk respectively, and outer irradiation channels are 0.119mk, 0.169mk, 0.348mk, 0.438mk and 0.418mk respectively, the highest excess reactivity result from flooding both inner and outer irradiation channels is 2.04mk (±1.72×10-7), the excess reactivity for LEU core was 0.299mk, 0.568mk, 0.896mk, 1.195mk and 1.524mk in the inner irradiation channels, and the outer irradiation channels are 0.129mk, 0.189mk, 0.219mk, 0.269mk and 0.548mk where the highest excess reactivity was 1.942mk (±1.64×10-7) resulting from flooding inner and outer irradiation channels. The reactivity induced by flooding of the irradiation channels of NIRR-1 with water is within design safety limit enshrined in Safety Analysis Report of NIRR-1. The results also compare well with literature.
authors.affiliation: Department of Physics, Sokoto State University, Sokoto, Nigeria.
authors.forename: U
authors.initials: U
authors.lastname: Iliyasu
authors.affiliation: Centre for Energy Research and Training, Ahmadu Bello University, Zaria, Nigeria.
authors.forename: Y V
authors.initials: YV
authors.lastname: Ibrahim
authors.affiliation: Department of Physics, Ahmadu Bello University, Zaria, Nigeria.
authors.forename: Sadiq
authors.initials: S
authors.lastname: Umar
authors.affiliation: Department of Physics, Ahmadu Bello University, Zaria, Nigeria; Department of Pure and Applied Physics, Veritas University, Bwari, Abuja, Nigeria. Electronic address: sundayagbo131@yahoo.com.
authors.forename: S A
authors.initials: SA
authors.lastname: Agbo
authors.affiliation: Department of Physics, Ahmadu Bello University, Zaria, Nigeria.
authors.forename: Y
authors.initials: Y
authors.lastname: Jibrin
keywords: Flooding; HEU; Irradiation; LEU; MNSR; Reactivity