Study On Neutronics Parameters Of IHNI Reactor And Precise Calculation On Cell Dosimetry For BNCT

Two main nuclear physics field of BNCT is researched in this article:1. Development of ideals neutron source devices.2. Dose measurement and evaluation technology. This paper do research on optimization of IHNI-I epithermal neutron beam equipment and analysis the character of epithermal neutron beam as well as research the effect of intercellular nonuniform distributions of10B to micro-dose.First, the MCNP51.51code and the continuous cross-section database of ENDF/B-VII used in this work is validated with standard core model of NUREG/CR-6115PWR reactor benechmark, and the simulation results indicate that the procedures and cross-section database is accurate and reliable.Then based on MCNP5, the model of in-hospital neutron irradiator IHNI-I is established, which is used to calculate physical parameters of y and neutron spectrum at the exit of epithermal and thermal neutron beam equipment espectively, and conclusion that the quality of epithermal neutron beam is lower than that of thermal neutron beam in the design of IHNI-I is drawn. Two type of optimization design for the epithermal neutron beam equipment is carried out for this reason. Fluental material will replace the former hybrid multi-layer Al/Al2O3as moderator in IHNI-I. New design of IHNI-I with35cm thickness of Fluental material and0.8mm B4C material which served as moderator and thermal neutron absorbing material respectively will be the substitution of the original design with Al/Al2O3hybrid multi-layer structure. Simulation results show that the improved design can provide higher quality beam than the origin one.Finally, to research the effect of intercellular nonuniform distribution of10B to micro-dose, the a-Li code version1.0was developed based on a Monte Carlo tool-Geant-4software kit to calculate the micro-dose of cell induced by α and ’Li particle, which are the products of10B(n,a)7Li. S value was calculated with variation of two types of cell size, eight different a particle energies and three kinds of source distribution.Differences between results of this code and an analytical algorithm of MIRD committee were within1%. On this basis, a total of3420 cases were calculated and analyzed, with different kinds of nucleus radius, cell radius, and source position combination, finally the differences of S-value of a particles and Li particle in cells is conformed. Cellular S values of10B(n,a)7Li calculated in this paper could be used to compute the high precision dose under the conditions of nonuniform distribution of10B compound in intercellular scale.