[en] A sub-channel blockage may be caused by ingression of damaged fuel debris or foreign obstacles into a core fuel subassembly for a liquid metal reactor(LMR) due to its geometrical compactness of the core design. Local coolant temperature could rise during the incident and it might eventually lead to the degradation of the fuel rods. An analysis computer code is obviously needed not only to assure the safe design of the core, but also to design an effective monitoring system to prevent it from propagating to a serious consequence. The code, therefore, must be capable of representing the thermal-hydraulic phenomena anticipated during the incident reasonably enough to be used to evaluate fuel rod intactness. Most of the technically leading countries for LMR have developed and are using the codes for sub-channel blockage analyses, Korea couldn't afford the resources sponsoring the develop of such a code past years. It was realized later that such an analysis code would ultimately be a prerequisite in the future licensing process of KALIMER as its conceptual design was being elaborated. Since those advanced countries had been reluctant to transfer such the codes, MATRA-LMR/FB had to be developed independently in Korea. It is a revised version of the existing MATRA-LMR code which was aimed for the core sub-channel analysis of LMRs. Some of its models have been improved so appropriately to be able to analyze the sub-channel blockages. Nevertheless, an experiment relevant to the sub-channel blockages had never been conducted for investigating the phenomenon in Korea. Further more, very few experimental data are available on published papers or reports world wide. Under this circumstance, a study has been made as an effort to evaluate the prediction capability of the MATRA-LMR/FB code by comparing the calculation results of the SABRE code, which had already been applied to EFR design. In result, a discrepancy has been observed in a case, but an overall agreement has been found between two predictions