Analysis of Nigeria Research Reactor-1 Thermal Power Calibration Methods

TLDR

Nigeria Research Reactor‑1 (NIRR‑1) is a low‑power miniature neutron source reactor at Ahmadu Bello University, Zaria. The study evaluates the accuracy of slope and heat‑balance calibration methods for NIRR‑1’s thermal power. Calibration was performed at 3.6 kW, 15 kW, and 30 kW using both slope and heat‑balance techniques. The heat‑balance method yielded 3.7 ± 0.2 kW, 15.2 ± 1.2 kW, and 30.7 ± 2.5 kW, while the slope method produced 15.8 ± 0.7 kW and 30.2 ± 1.5 kW at 15 kW and 30 kW, indicating the slope method is more accurate at higher powers but unsuitable at low power.

Abstract

This paper analyzes the accuracy of the methods used in calibrating the thermal power of Nigeria Research Reactor-1 (NIRR-1), a low-power miniature neutron source reactor located at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria, Nigeria. The calibration was performed at three different power levels: low power (3.6 kW), half power (15 kW), and full power (30 kW). Two methods were used in the calibration, namely, slope and heat balance methods. The thermal power obtained by the heat balance method at low power, half power, and full power was 3.7 ± 0.2 kW, 15.2 ± 1.2 kW, and 30.7 ± 2.5 kW, respectively. The thermal power obtained by the slope method at half power and full power was 15.8 ± 0.7 kW and 30.2 ± 1.5 kW, respectively. It was observed that the slope method is more accurate with deviations of 4% and 5% for calibrations at half and full power, respectively, although the linear fit (slope method) on average temperature-rising rates during the thermal power calibration procedure at low power (3.6 kW) is not fitting. As such, the slope method of power calibration is not suitable at lower power for NIRR-1.