Speaker
Description
The small modular sodium-cooled fast reactor (SFR) is an important component of Generation-IV reactors. For SFR, one type beyond design basis accidents (BDBA) that has received special attention is the anticipated transients without scram (ATWS) events including unprotected loss of coolant flow (ULOF) accident, unprotected loss of heat sink (ULOHS) accident and unprotected transient overpower (UTOP) accident. The modular design for multiple purposes and remote region operation requires usually very infrequent refueling strategy. During a long-lived operation, the neutronic characteristics of SFR core, for instance, the coolant void effect and the Doppler effect, vary and hence the reactor safety performance in ATWS events. This paper focuses on the analysis of safety performance of a 300 MWth small modular MOX SFR from its beginning of life (BOL, 0 GWd/tHM) to its end of life (EOL, 75 GWd/tHM). The burnup calculation is conducted by using Monte-Carlo code OpenMC with pin-by-pin depletion mesh. The elementary reactivity feedback coefficients and core power distribution are compared at different burnup depth. The transient behavior is simulated by using a newly developed mono-channel point kinetic system code dedicated to fast reactors. The inherent reactivity feedback mechanism in ATWS is classified. The influence of the fuel burnup, the power redistribution, and the control rod positions are investigated. Some solutions, for instance, the use of burnable poisons, the design of upper sodium plenum, the addition of moderators, are discussed in the view of mitigation of the ATWS impact and the inherent safety performance for a long operating lifetime.
| Speaker's title | Mr |
|---|---|
| Affiliation/Organization | Shanghai Jiao Tong University |
| Country/Int. organization | China |
| Speaker's email address | jinxinsjtu@sjtu.edu.cn |
