Study on the natural circulation characteristics of the integral type reactor for vertical and inclined conditions

To investigate the thermal-hydraulic characteristics during natural circula tion in an integral type marine reactor, basic single-phase natural circula tion experiments were performed using scaled test facilities of the System- integrated Modular Advanced Reactor (SMART), and the RETRAN-03/INT code was developed. For both vertical and inclined conditions, the flow distributio n through eight steam generator cassettes and thermal mixing in downcomer r egions were observed. It was found that feedwater isolation does not enhanc e the asymmetric temperature distribution at the outlets of the steam gener ator cassettes. For inclined conditions, the results show typical flow char acteristics according to the inclination angles. Flow rates in ascending st eam generator cassettes increase by the increase in the thermal driving hea d, and consequently the outlet temperatures increase. Analytical and experi mental results showed good agreements and it was concluded that RETRAN-03/I NT is sufficiently capable of analyzing three-dimensional phenomena in an i ntegral type reactor. (C) 2001 Elsevier Science B.V. All rights reserved.