Indian Journal of Science and Technology

Abstract

Background/Objectives: Accelerator Driven Systems (ADS) need a neutron source to compensate neutron deficiency. The neutrons are produced using an accelerator (a proton type) by the injection of protons into a target by spallation reactions. Methods/Statistical Analysis: Since the target represents coupling of accelerator and sub-critical core, a main parameter in spallation calculations is the neutron yield on target. Spallation process computation has been done and the ability to transport particles using various physics models has been studied. A comparative study of transport models has been investigated for a lead target to compute neutron production in several cases. Results: Although modifying default values, will adjust models to the required problem to obtain the related accurate yield, some cases seem more accurate. Moreover the sub-criticality status of the defined ADS was studied by measuring the effective multiplication factor; the final value tends to a less than one asymptotic value for such system. Neutron yield was also demonstrated with the variation of target radius as well as proton energy and resulted that in radii less than proton beam’s radius, neutron production increases rapidly while in larger radii it has a smooth increase and remains almost steady near a constant value. The optimum radius was determined at 7.5-8 cm. Conclusion/Application: The sub-criticality status of the defined specific ADS was investigated by measuring the effective multiplication factor (k_eff) using MCNPX2.6.0 code. The final value tends to an asymptotic value which is definitely less than one, for a subcritical system.
Keywords: ADS, MCNPX, Neutron Yield, Spallation, Transport Model