NECP-MCX is an inhouse hybrid Monte-Carlo-Deterministic particle-transport code developed by Xi'an Jiaotong University. The advanced hybrid Monte-Carlo-Deterministic method is adopted for variance reduction. Therefore, this code is suitable for the efficient analysis of the deep-penetration radiation shielding problem. It has various functions such as criticality calculation, fixed-source calculation, transport-burnup-activation coupling simulation, neutron-photon coupling transport calculation, multi-group Monte Carlo, sensitivity coefficient calculation and so on. NECP-MCX can be used for radiation shielding design, neutronics analysis of fusion reactor, nuclear reactor criticality calculation, etc. It has been verified and validated by plenty of benchmarks. The specific characteristics of the code are summarized as follows:

(1) For the deep-penetration problem, the hybrid Monte-Carlo-Deterministic method is adopted to automatically generate the weight window and source bias parameters to improve the figure of merit (FOM). For the HBR-2 reactor shielding problem, the FOM of the hybrid Monte-Carlo-Deterministic method is more than 1000 times higher than that of the weight window generator (WWG) of MCNP. By using the adaptive nested grid technology, the data storage of the weight window is reduced to 1/200.

HBR-2 benchmark flux distribution and importance distribution

(2) Based on constructive solid geometry (CSG) method for the geometric processing, complex geometry can be described by NECP-MCX. Repeated geometries such as the reactor core can be easily described using the hierarchical structure, such as Lattice, Cell, Universe and so on.

(3) The input card of MCNP be used directly for geometry and material modeling. Therefore, workload of the users can be saved.

(4) By using the slave-slave parallel mode and the nearest neighbor algorithm, the thousand-core parallelism efficiency reaches 90%.

(5) The photon energy deposition model of the code is based on the photon collision kerma, which is more rigorous than the ICRU kerma.

(6) A point-kernel integral module is integrated in NECP-MCX. Based on one input file, users can perform a precise photon dose assessment using the Monte Carlo method or a rapid photon dose assessment by the point-kernel integral method.

(7) NECP-MCX is able to generate the input card and cross-section file of the large-scale discrete ordinate transport calculation code NECP-Hydra, thus can simplify the modeling process of NECP-Hydra.

(8) The code has the functions of transport-burnup-activation coupling simulation, neutron-photon coupling transport, multi-group Monte Carlo and sensitivity coefficient calculation of eigenvalues on nuclear data, etc.

(9) The code has been verified and validated by more than 300 benchmarks or measured results of SINBAD, ICSBEP, Mosteller, INDC, VERA, a small lead-bismuth reactor, AP1000 and so on.