Heat pumps hybrid systems using

The hybrid heat transport system (HHTS). The MR employs natural circulation and a self-pressurized primary coolant system, altogether resulting in a simple primary system design without reactor coolant pumps and pressurizer it also reduces maintenance requirements. In addition, the use of HHTS concept makes it possible to reduce the size of the reactor vessel. The HHTS is a kind of two-phase natural circulation system. The coolant starts boiling in the upper part of the core two-phase coolant flows up in the riser and is condensed and cooled by SGs. Such design approach increases coolant flow rate and thus, reduces the required height of the reactor vessel (RV) to transport the heat from the core, Fig. VI-2. 

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