SCIENCE

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Browsing SCIENCE by Author "ABALENI, JOSEPH ISTIFANUS"

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    DETERMINATION OF IRRADIATED CONTROL ROD WORTH OF NIGERIAN RESEARCH REACTOR – 1 (NIRR – 1) USING THE OPERATIONAL DATA
    (2017-05) ABALENI, JOSEPH ISTIFANUS
    An important parameter in the design and analysis of a nuclear reactor is the reactivity worth of the control rod which is a measure of the efficiency of the control rod to absorb excess reactivity. During reactor operation, the control rod worth is affected by factors such as fuel burnup, Xenon concentration, Samarium concentration and position of the control rod in the core. This study investigates and utilizes the operational data of the reactor to determine the control rod worth of Nigeria research reactor – 1 (NIRR – 1) after 7 years of operation. The reactor operational data were exported from the reactor computer system (logbook) to Microsoft excel spread sheet and were analyzed in terms of the neutron flux and burn up time. The initial number of atoms in the cadmium rod was calculated using the dimension of the control rod and equation 3.8 and is found to be 8.8705554 x 1046/mole. The final number of atoms in the cadmium rod was calculated using a decay equation (equation 3.5) to be 8.8346840 x 1046/mole. The fractional change in the number of atoms was estimated from the results and the control rod worth was determined to be 6.97mk. The shutdown margin (SDM) and the safety reactivity factor (SRF) were also evaluated from the result and were found to be 3.08mk and 1.79 respectively. Since the reactivity worth of control elements will change due to both the depletion of control absorber nuclei and changes in the core power distribution, control management analysis must continually monitor the worth of the control system component throughout core life in order to maintain both an adequate shutdown margin and sufficient operating maneuverability
  • Item
    DETERMINATION OF IRRADIATED CONTROL ROD WORTH OF NIGERIAN RESEARCH REACTOR – 1 (NIRR – 1) USING THE OPERATIONAL DATA
    (2017-05) ABALENI, JOSEPH ISTIFANUS
    An important parameter in the design and analysis of a nuclear reactor is the reactivity worth of the control rod which is a measure of the efficiency of the control rod to absorb excess reactivity. During reactor operation, the control rod worth is affected by factors such as fuel burnup, Xenon concentration, Samarium concentration and position of the control rod in the core. This study investigates and utilizes the operational data of the reactor to determine the control rod worth of Nigeria research reactor – 1 (NIRR – 1) after 7 years of operation. The reactor operational data were exported from the reactor computer system (logbook) to Microsoft excel spread sheet and were analyzed in terms of the neutron flux and burn up time. The initial number of atoms in the cadmium rod was calculated using the dimension of the control rod and equation 3.8 and is found to be 8.8705554 x 1046/mole. The final number of atoms in the cadmium rod was calculated using a decay equation (equation 3.5) to be 8.8346840 x 1046/mole. The fractional change in the number of atoms was estimated from the results and the control rod worth was determined to be 6.97mk. The shutdown margin (SDM) and the safety reactivity factor (SRF) were also evaluated from the result and were found to be 3.08mk and 1.79 respectively. Since the reactivity worth of control elements will change due to both the depletion of control absorber nuclei and changes in the core power distribution, control management analysis must continually monitor the worth of the control system component throughout core life in order to maintain both an adequate shutdown margin and sufficient operating maneuverability.