Thermal Hydraulic Analysis of China Spallation Neutron Source Target System Under Abnormal Situations

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Jun-Hong Hao ◽  
Qun Chen ◽  
You-Lian Lu ◽  
Song-Lin Wang ◽  
Quan-Zhi Yu ◽  
...  
Keyword(s):  
Proton Beam ◽  
Neutron Source ◽  
Cooling Water ◽  
Normal Operation ◽  
Maximum Temperature ◽  
Target System ◽  
Monte Carlo Code ◽  
Operating Pressure ◽  
Spallation Neutron Source ◽  
Power Failure

The analysis of thermal hydraulic performance under three abnormal conditions is very important for the design of China spallation neutron source (CSNS) target system, which could provide some important information for developing an emergency plan. In this study, we first introduce the design of the CSNS target system and create a three-dimensional physical model, calculate the heat source and decay heat distribution using the MCNPX 2.5 Monte Carlo code and the CINDER’90 activation code, and simulate and analyze the temperature distribution in the tungsten target and the steel container under normal operation using fluent. By using the same model, the thermal hydraulic characteristics are analyzed under three different abnormal conditions including power failure, off-center of proton beam, and cooling water failure. The results show that in order to keep the cooling water temperature below the boil point at normal operating pressure, the emergency power for the cooling water should start immediately after power failure. The maximum temperature of the beam window and the up plate increases by about 8 °C when the offsetting distance of proton beam is 5 mm along z direction. The cooling water will not effectively take all away the heat when the flow rate of the cooling water drops below 72% of the normal setpoint.

scholarly journals Simulating neutron transport in long beamlines at a spallation neutron source using Geant4

2020 ◽  
Vol 22 (2-3) ◽  
pp. 183-189
Author(s):  
Douglas D. DiJulio ◽  
Isak Svensson ◽  
Xiao Xiao Cai ◽  
Joakim Cederkall ◽  
Phillip M. Bentley
Keyword(s):  
Monte Carlo ◽  
Neutron Source ◽  
Variance Reduction ◽  
Neutron Transport ◽  
High Energy ◽  
Low Energy ◽  
Deep Penetration ◽  
Monte Carlo Code ◽  
Spallation Neutron Source ◽  
Unique Challenge

The transport of neutrons in long beamlines at spallation neutron sources presents a unique challenge for Monte-Carlo transport calculations. This is due to the need to accurately model the deep-penetration of high-energy neutrons through meters of thick dense shields close to the source and at the same time to model the transport of low- energy neutrons across distances up to around 150 m in length. Typically, such types of calculations may be carried out with MCNP-based codes or alternatively PHITS. However, in recent years there has been an increased interest in the suitability of Geant4 for such types of calculations. Therefore, we have implemented supermirror physics, a neutron chopper module and the duct-source variance reduction technique for low- energy neutron transport from the PHITS Monte-Carlo code into Geant4. In the current work, we present a series of benchmarks of these extensions with the PHITS software, which demonstrates the suitability of Geant4 for simulating long neutron beamlines at a spallation neutron source, such as the European Spallation Source, currently under construction in Lund, Sweden.

Integration of Proton Beam Collimation Scheme in the Spallation Neutron Source (SNS) Accumulator Ring Including Dose and Activation Estimates

2004 ◽  
Author(s):  
Nicholas Simos ◽  
Hans Ludewig ◽  
D. Raparia ◽  
N. Catalan-Lasheras ◽  
S. Cousineau ◽  
...  
Keyword(s):  
Proton Beam ◽  
Neutron Source ◽  
High Energy ◽  
Ring Structure ◽  
Integration Scheme ◽  
Spallation Neutron Source ◽  
Energy Beam ◽  
Optimization Study ◽  
Ring Section ◽  
Final Proton

This paper details the integration scheme as well as the induced activation by the proton beam clean-up system (collimation) in the accumulator ring section of the Spallation Neutron Source (SNS) accelerator complex. Specifically, the results of the optimization study in terms of satisfying both the optics of the proton beam and the minimization of activation of the accelerator components as well as of the surrounding structure have guided both the design of the components and their integration and are presented in this paper. The resulted collimation scheme is a two-stage clean-up system consisting of proton beam halo intercepting scrapers and appropriate fixed aperture absorbers. The accumulator ring structure consists of the High Energy Beam Transfer (HEBT) line which receives the 1 GeV proton beam from the SNS LINAC accelerator, the accumulator ring itself which compiles the micro-pulses into the final 60 Hz pulse, and the RTBT line that transfers the final proton pulse to the accelerator target. Collimation takes place in all three ring components and along respective straight sections with the exception of the off-momentum particle clean-up in the HEBT line in which off-momentum protons are guided to a stationary absorber outside the transfer line. Given that the activation issues of the collimating structures themselves as well as of the nearby accelerator components (mainly magnets) are similar in all sections of the ring, the activation of components in the ring clean-up system will be discussed in detail in the following sections.

scholarly journals Thermal Analyses and Frequency Shift Design Studies for the Spallation Neutron Source Drift Tube Linac

2001 ◽  
Author(s):  
Lucie Parietti
Keyword(s):  
Finite Element ◽  
Frequency Shift ◽  
Neutron Source ◽  
Drift Tube ◽  
Waste Heat ◽  
Cooling System ◽  
Normal Operation ◽  
Spallation Neutron Source ◽  
Rf Heating ◽  
Drift Tube Linac

Abstract Los Alamos National Laboratory is responsible for the design of the room-temperature linac for the Spallation Neutron Source (SNS). This linac consists of a Coupled-Cavity Linac (CCL) and a Drift Tube Linac (DTL). During normal operation, about 80% of the Radio Frequency (RF) power is dissipated in the DTL cavity walls. This waste heat causes the cavities to expand, causing shifts in their RF resonant frequency. The DTL relies on the water cooling system to compensate for the frequency shift caused by RF heating. To guide the design of the cooling system and the frequency control scheme, thermal expansion and frequency shift studies for several DTL cells are performed via numerical simulations. Temperature distributions and thermal deformations resulting from RF heating are evaluated separately for the tanks and 22 drift tubes using finite element models. The frequency shift of these cells are then computed based on the calculated deformations. Size and locations of the cooling channels are designed accordingly to provide adequate cooling and minimize frequency shift. The tank finite element model used to predict the tank temperature profile is benchmarked against experiment data.

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