Conceptual design of a small-pressurized water reactor using the AP1000 fuel assembly design

This paper presents the conceptual design of a 300 MWt small modular reactor (SMR)using fuel assemblies of the AP1000 reactor. Numerical calculations have been performed to evaluate a proper active core size and core loading pattern using the SRAC code system and the JENDL-4.0 data library. The analysis showed that Doppler, moderator temperature, void, and power reactivity coefficients are all negative over the core lifetime. Semi-analytical thermal hydraulics analysis reveals acceptable radial and axial fuel element temperature profiles with significant safety margin of fuel andclad surface temperature. The minimum departure from nucleate boiling ratio (MDNBR) is also calculated. The results indicate that a cycle length of 2.22 years is achievable while satisfying the operation and safety-related design criteria with sufficient margins.

Effect of MOX fuel and the ENDF/B-VIII on the AP1000 neutronic parameters calculations by using MCNP6

The present work studies the effect of introducing MOX fuel on Westinghouse AP1000 neutronic parameters. The neutronic calculations were performed by using the MCNP6 code with the ENDF/B-VII.1 library and the new release of the ENDF/B-VIII, the AP1000 core with three 235U enrichment zones (2.35 %, 3.40 %, and 4.45 %). The obtained results showed that the simulated model for the AP1000 core satisfies the optimization criteria as a Westing- house reference. The results which included: effective multiplication factor, keff, delayed neutron fraction, beff, excess reactivity, rex, shutdown margin, temperature reactivity coefficients, whole core depletion, neutron flux, power peaking factor and core power density, were calculated and compared with the available published results. The keff in the cold zero power was found to be 1.20495 and 1.20247 with the ENDF/B-VII.1 and the ENDF/B-VIII libraries, respectively, which matches the value of 1.205 presented in the AP1000 Design Control Document for the UO2 fuel core. On the other hand, keff in the cold zero power was found to be 1.19988 and 1.19860 for MOX core with the ENDF/B-VII.1 and the ENDF/B-VIII libraries, respectively, which show good reception and confirm the safety of the design and efficient modeling of AP1000 reactor core.

Reliability analysis of the precision assembly process of a scaled stator can of the AP1000 reactor coolant pump

In this study, a reliability model for the assembly process of a stator can on the stator core in the AP1000 reactor coolant pump in a reduced scale is developed. Firstly, the tube hydroforming-based stator can assembly method is reviewed briefly. In order to extract the factors affecting the assembly results, a numerical assembly model and an assembly experiment rig are established. Assembly results are predicted by numerical analysis and validated by experiment. A reliability model with the proposed corrected-partial least squares regression-response surface method (C-PLSR-RSM)-based system reliability method is developed. The model is applied to analyze the assembly reliability of the stator can, and the effects of failure dependency on the estimation accuracy of reliability, as well as the relationships between the assembly reliabilities and different single evaluation index. The results indicate that the reliability model is able to efficiently analyze the implicit stator can assembly problem. Failure correlation brings a negative correlation relationship between the different assembly performance functions.