Validation of the HOTCHAN code for analyzing the EBR-II core following an unprotected loss of flow

A series of reactor experiments involving unprotected (no scram) loss-of-primary flow (LOF) down to natural convection was successfully conducted in February and April of 1986 on the Experimental Breeder Reactor II (EBR-II). The predicted and measured behavior of a special instrumented assembly, the XX09-fueled INSAT, was compared for the most severe test (SHRT 45) to demonstrate the validation of the thermal-hydraulic code HOTCHAN. The particular test of interest in this paper was initiated at full power by tripping the primary and secondary pumps. These tests were part of the shutdown heat removal tests (SHRT) being conducted in EBR-II. The reactor and balance of plant are extensively instrumented, and measurements were recorded by a data acquisition system. The reactor and plant response confirm predictions that the driver fuel cladding can survive temperatures above the eutectic threshold for the transient following a station blackout without scramming the reactor. In addition, the in-core data provide a firm basis for validation of the Argonne/EBR-II developed HOTCHAN code for analyzing the thermal-hydraulic behavior of specific fuel subassemblies. In this paper the analytical model for HOTCHAN is described as well as it relationship to the NATDEMO code. The predicted behavior of the hottest driver subassembly ismore » also discussed and compared with the INSAT XX09 results.« less