Nuclear reactor and method for control thereof

A method for controlling a nuclear reactor,

• the nuclear reactor comprising:
• a reactor vessel having therein
• an internal cavity comprising primary coolant, including water,
• a riser tube, and
• a reactor core located below the riser tube,
• an outer annulus
• surrounding the reactor vessel and the riser tube
• forming a downcomer with a given flow area and
• configured to produce a primary coolant flow rate above 10,000 kg/s with a pressure within a range of 6 and 15 bars,
• the reactor core being located below ground level at, at least, 55 meters depth;
• a steam drum connected to the riser tube via an upper end of the riser tube,
• the steam drum being located at ground level with a pressure within a range between 1 and 10 bars;
• a water storage tank
• connected to the reactor vessel
• and storing borated water;
• a passive injection system configured to cause the borated water from the water storage tank to be injected into the reactor vessel;
• one or more steam turbines configured to generate power at a pressure of 1-10 bars,
• wherein the method comprises
• heating, by the reactor core, water up to a certain temperature, without reaching a saturation point, and
• converting, by the riser tube, the heated water to steam, and
• delivering the steam to the one or more steam turbines via the steam drum,
• whereby the converting step creates a difference in a primary coolant density that achieves a density-driven natural circulation of the primary coolant in the riser tube, the downcomer, the steam drum, and the reactor core.