Shielding Design And Simulation Of The PGNAA System Based On CARR

Prompt gamma neutron activation analysis (PGNAA) is high sensitive and non-destructive, etc, and the increasingly wide range of applications, which is based on neutron capture prompt y-ray nuclear reaction nuclear analytical techniques. This paper is a combination of Chinese Institute of Atomic Energy of the current (CIAE) of the Advanced Research Reactor (CARR) neutron activation analysis platform infrastructure projects, In order to meet the construction of the thermal neutron instant gamma activation analysis system. In reference to the construction experience of the international advanced PGNAA system lab, this article completes the design in high standards for CARR’s neutron instant gamma activation analysis system.Monte Carlo method will be used for the device systems’shielding design, and determine the overall structure of the device. According to the source data of CARR reactor, using MCNP5 program to do some more detailed calculation of the PGNAA system. Roughly determined the basic shielding materials and the geometric parameters of related components, It will be to provide certain technical reference data for the smooth construction of the system.In this paper, the completed works can be mainly concluded as the following parts:(1) Considering that different shielding materials have different interaction characteristic with neutron and photon, this article calculates several shielding materials’transmission coefficient. Then according to the radiation protection requirements, selects the suitable shielding materials, these work can provide theoretical basis for shield design in next step.(2) Based on the source data which is provided by the core, Simulations are conducted on shielding design works, selecting the heavy concrete, which density is 5.0g/cm3, completes the shielding design for the collimation pipeline, and at the same time implement the alignment design for the collimating pipes, limit the particle beams’radius within 1cm which moves from core to sample room. Then using MCNP5 program complete the shield design work for the sample room, beem stop device and detectors. Selecting proper shielding materials and shielding structure, to make the shielding design work can reduce the background as more as possible, at the same time reduce the scattering neutron damage to the detectors, thus reduce the dose equivalent rate around the system and meet the requirements of radiation protection.(3) According to the characteristics of prompt gamma-ray and select suitable composition detection system, while the system of detectors energy and efficiency calibration and completed the initial instant activation assay.Based on the above work, this paper design the shielding and simulate PGNAA entire system, including the ex-core collimator shield design, sample room design, to prevent detection system design and design. While were discussed the detector energy and efficiency calibration. In this paper, a series of work will be to build on the successful implementation of the future system platforms and provide a preliminary design basis. The successful completion of the future will provide the necessary technical support and theoretical basis for thermal neutron PGNAA system of CARR.