“…The peak cladding temperature rises to 660°C slightly after the end of pump coast down. The peak clad temperature increase is very mild and within the design limit, which can be compared with the maximum 750°C peak clad temperature predicted for the ABTR design 19 . The second peak of the peak cladding temperature arrives around half an hour later at much lower value.…”
“…The peak cladding temperature rises to 660°C slightly after the end of pump coast down. The peak clad temperature increase is very mild and within the design limit, which can be compared with the maximum 750°C peak clad temperature predicted for the ABTR design 19 . The second peak of the peak cladding temperature arrives around half an hour later at much lower value.…”
“…Before the safety analyses of SLFFR, verification tests of the MUSA code were performed by a code-to-code comparison with the well-validated safety analysis code SAS4A/SASSYS-1. The steady-state operating conditions and the ULOF accident scenario of the advanced burner test reactor (ABTR) were analyzed using the MUSA code, and the results were compared with the reference solutions obtained with the SAS4A/SASSYS-1 code system (Dunn, et al, 2006).…”
Section: Verification Tests Of Musa Codementioning
Safety characteristics have been evaluated for the stationary liquid fuel fast reactor (SLFFR) proposed for effective burning of hazardous TRU elements of used nuclear fuel. In order to model the geometrical configuration and reactivity feedback mechanisms unique to SLFFR, a multi-channel safety analysis code named MUSA was developed. MUSA solves the timedependent coupled neutronics and thermal-fluidic problems. The thermal-fluidic behavior of the core is described by representing the core with one-dimensional parallel channels. The primary heat transport system is modeled by connecting compressible volumes by liquid segments. A point kinetics model with six delayed neutron groups is used to represent the fission power transients. The reactivity feedback is estimated by combining the temperature and density variations of liquid fuel, structural material and sodium coolant with the corresponding axial distributions of reactivity worth in each individual thermal-fluidic channel. Preliminary verification tests with a conventional solid fuel reactor agreed well with the reference solutions obtained with the SAS4A/SASSYS-1 code. Transient analyses of SLFFR were performed for unprotected transient overpower (UTOP), unprotected loss of heat sink (ULOHS) and unprotected loss of flow (ULOF) accidents. The results showed that the thermal expansion of liquid fuel provides sufficiently large negative feedback reactivity for passive shutdown of UTOP and ULOHS. The ULOF transient is also terminated passively with the negative reactivity introduced by the gas expansion modules installed at the core periphery. The maximum coolant temperatures have sufficient margins to the sodium boiling point for all three unprotected transient scenarios.
“…The lack of general thermal mixing and stratification models in those codes severely limits their application and accuracy for safety analysis, especially for passively safe advanced light-water reactors (ALWRs), where the primary system and containments are more strongly coupled (Zhao and Peterson, 2010). The SASSYS code developed by argonne national laboratory (ANL), only provides lumped-volume-based 0-D models that can only give very approximate results and can only handle simple cases with one mixing source (Dunn et al, 2006). COMMIX code developed by ANL uses CFD tools to analyze simple configuration small-scale thermal stratification problems and achieved limited success (Chang and Bottoni, 1994;Kasza et al, 2007).…”
Section: Thermal Stratification In Large Poolsmentioning
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.