Passive cooling system in a nuclear spent fuel pool using a vertical straight wickless-heat pipe

To enhance the thermal safety when a station blackout accident occurs, a vertical, straight, wickless-heat pipe is
proposed as a passive residual heat removal system on the nuclear spent fuel pool. The heat pipe will remove the
decay heat from the nuclear spent fuel pool and keep the system safe. The objective of this research is to
investigate the thermal performance of a vertical, straight, wickless-heat pipe that will be proposed as a new
passive cooling system on the nuclear spent fuel pool. An experiment was conducted to investigate the heat
transfer phenomena and heat pipe thermal performance. It considered the in
fl
uence of the heat pipe initial
pressure, evaporator
fi
lling ratio, evaporator heat load, and coolant volumetric
fl
ow rate of the water jacket. The
simulation with the nuclear reactor thermal-hydraulic code RELAP5/MOD3.2 was performed to support and
compare it with the experimental results. Cooled water was circulated in a water jacket as a condenser cooling
system. The experimental results showed that the best thermal performance was obtained at a thermal resistance
of 0.016 ± 0.0006 °C/W, a
fi
lling ratio of 80%, a lower initial pressure, a higher coolant volumetric
fl
ow rate,
and a higher heat load of the evaporator. The RELAP5/MOD3.2 simulation model can be used to support ex-
perimental investigation and predict the phenomena inside a heat pipe. It was compared with other heat pipe
research results, experimental and simulation results showed that the vertical, straight, wickless-heat pipe had
higher thermal performance and can be proposed as a passive residual heat removal system of a nuclear spent
fuel pool when a station blackout occurred