currently most nuclear power stations must operate below the temperatures and pressures that coal-fired plants do, in order to provide more conservative safety margins within the systems that remove heat from the nuclear fuel rods. this, in turn, limits their thermodynamic efficiency to 30–32%. some advanced reactor designs being studied, such as the very-high-temperature reactor, advanced gas-cooled reactor, and supercritical water reactor, would operate at temperatures and pressures similar to current coal plants, producing comparable thermodynamic efficiency.