Cevallos-Robalino Lenin E, García-Baonza Roberto, García-Fernández Gonzalo, Gallego Eduardo, Vega-Carrillo Hector Rene
Carrera de Ingeniería Electrónica, Grupo de Investigación en Micro-Nanotecnología y Energía Nuclear, (NANOTECH), Universidad Politécnica Salesiana (UPS), C. Robles 107 Chambers, 090108, Guayas, Guayaquil, Ecuador.
Departamento de Ingeniería Energética, ETSI Industriales, Universidad Politécnica de Madrid (UPM), C. José Gutiérrez Abascal 2, 28006, Madrid, Spain.
Appl Radiat Isot. 2022 Jan;179:109992. doi: 10.1016/j.apradiso.2021.109992. Epub 2021 Oct 25.
FANT (Fuente Ampliada de Neutrones Térmicos; in Spanish) is a thermal neutron irradiation facility with an extended and very uniform irradiation area, that has been developed by the Neutron Measurements Laboratory of the Energy Engineering Department at Universidad Politecnica de Madrid (LMN-UPM). This device is a parallelepiped box made of high-density polyethylene (HDPE), moderator material, that uses an A95241m/B49e neutron source of 111 GBq nominal activity for irradiating materials. The facility design was previously optimized, and the neutron spectra were estimated by extensive calculations with the MCNP6.1 code and carrying out experimental measurements (Bedogni et al., 2017). The facility takes advantage of the scattering reactions of neutrons with the HDPE surfaces of the chamber, where the moderation process is effective, achieving relevant thermal neutron fluence rates. The main goal of this work has been to simulate and analyse the FANT system by Monte Carlo methods using the MCNP6.1 code, employing 3 different nuclear data libraries: ENDF/B-VII.1, JEFF-3.3 and TENDL 2017. The transport of thermal neutrons in HDPE, E < 1eV, has been calculated in all the cases taking into account the thermal S (α,β) treatment. The results achieved in this work have been compared with those previously obtained in the former development of FANT, using the MCNP6.1 code with the ENDF/B-VII.1 nuclear data, and experimental measurements. These results have shown that the JEFF-3.3 nuclear data library is the nuclear data library that provides of the best matching between the MCNP computational results, and the experimental data collected at FANT. Hence, the JEFF-3.3 nuclear data library seems to be the most correct library to design and benchmark thermal neutron activation devices.
FANT（西班牙语为Fuente Ampliada de Neutrones Térmicos）是一种热中子辐照设施，其辐照区域广阔且非常均匀，由马德里理工大学能源工程系中子测量实验室（LMN - UPM）开发。该装置是一个由高密度聚乙烯（HDPE）制成的平行六面体箱，HDPE为慢化材料，它使用标称活度为111 GBq的A95241m/B49e中子源来辐照材料。该设施的设计先前已进行优化，通过使用MCNP6.1代码进行大量计算并开展实验测量来估计中子能谱（贝多尼等人，2017年）。该设施利用中子与腔室HDPE表面的散射反应，在该表面慢化过程有效，从而实现了可观的热中子注量率。这项工作的主要目标是使用MCNP6.1代码，通过蒙特卡罗方法，采用3种不同的核数据库：ENDF/B - VII.1、JEFF - 3.3和TENDL 2017，对FANT系统进行模拟和分析。在所有情况下，都考虑了热S(α,β)处理，计算了能量E < 1eV的热中子在HDPE中的输运。将这项工作中获得的结果与先前在FANT的前期开发中使用带有ENDF/B - VII.1核数据的MCNP6.1代码以及实验测量所得到的结果进行了比较。这些结果表明，JEFF - 3.3核数据库是在MCNP计算结果与在FANT收集的实验数据之间提供最佳匹配的核数据库。因此，JEFF - 3.3核数据库似乎是设计和基准测试热中子活化装置的最正确的数据库。
