Scaling Experimental Design of Horizontal Steam Generator in NHR200-II

To broaden the application range and improve the economic feasibility of 200 MW Low-Temperature Nuclear Heating Reactor (NHR200-Ⅱ), a redesign of its intermediate loop has been proposed, including a new superheated steam supply system that incorporates horizontal steam generators (HSG). Due to the high cost and long period of prototype scale verification tests, a scaling modeling analysis of the two-phase natural circulation within the HSG was employed using the Hierarchical Two Tiered Scaling (H2TS) method. Theoretical derivations provided scaling analysis criteria under isothermal conditions and scaling numerical values under various scaling conditions. Both the prototype and the model employed water as the test fluid, and numerical modeling of the prototype and the model was conducted by using the RELAP5 code. The numerical calculations indicated that the key parameters’ proportional relationships between the model and the prototype were consistent with the theoretically derived results. Considering factors such as test economy, accuracy, and safety, a 1:4 scale model-to-prototype length ratio was ultimately selected as the scaling factor for subsequent verification tests, corresponding to a power ratio of 1:96.