NATURAL CIRCULATION REACTOR, ESPECIALLY BOILING WATER REACTOR, AND PROCESS FOR REGULATING THE CORE COOLANT FLOW RATE OF A NATURAL CIRCULATION REACTOR

摘要

The invention relates to a natural circulation reactor (1), especially a boiling water reactor, with a reactor pressure vessel (2), a reactor core (3) and a core jacket (4) surrounding said reactor core (3), which is arranged inside the reactor pressure vessel (2) and has at least one inlet (5) and one outlet (6) for core coolant. A flow path (8) for core coolant (7) formed between the core jacket (4) and the reactor pressure vessel (3) leading further through the inlet (5) has a flow cross section (9) with at least one throttle element (10) fitted in the flow path (8) by means of which the flow cross section (9) can be altered to regulate the flow rate of the core coolant. By altering the cross-sectional area of the throttle element (10) it is possible to reduce and increase the flow cross section (9) so that the power of the natural circulation reactor can easily be regulated and a power reduction to about 40 % of the momentary reactor power is ensured in the event of an incident. The invention also relates to a process for regulating the core coolant flow through a reactor core (3) of a natural circulation reactor.