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Title: Status of the Spallation Neutron Source with Focus on Target Materials

Authors:
 [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
931432
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Materials; Journal Volume: 356; Journal Issue: 1-3
Country of Publication:
United States
Language:
English

Citation Formats

Mansur, Louis K, and Haines, John R. Status of the Spallation Neutron Source with Focus on Target Materials. United States: N. p., 2006. Web. doi:10.1016/j.jnucmat.2006.05.031.
Mansur, Louis K, & Haines, John R. Status of the Spallation Neutron Source with Focus on Target Materials. United States. doi:10.1016/j.jnucmat.2006.05.031.
Mansur, Louis K, and Haines, John R. Sun . "Status of the Spallation Neutron Source with Focus on Target Materials". United States. doi:10.1016/j.jnucmat.2006.05.031.
@article{osti_931432,
title = {Status of the Spallation Neutron Source with Focus on Target Materials},
author = {Mansur, Louis K and Haines, John R},
abstractNote = {},
doi = {10.1016/j.jnucmat.2006.05.031},
journal = {Journal of Nuclear Materials},
number = 1-3,
volume = 356,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • This paper summarizes the ongoing evaluation of the susceptibility of materials in accelerator target/blanket cooling loops to corrosion. To simulate the exposure environment in a target/blanket cooling loop, samples were irradiated by an 800 MeV proton beam at the A6 Target Station of the Los Alamos Neutron Science Center (LANSCE). To accomplish this, a cooling water loop capable of exposing corrosion samples to an 800 MeV proton beam at currents upwards of 1 mA was constructed. This loop allowed control and evaluation hydrogen water chemistry, water conductivity, and solution pH. Specially designed ceramic sealed samples were used to measure themore » real-time corrosion rates of materials placed directly in the proton beam using electrochemical impedance spectroscopy (EIS). EIS was also used to measure real-time corrosion rates of samples that were out of the proton beam and downstream from the in-beam samples. These out-of-beam probes primarily examined the effects of long lived water radiolysis products from proton irradiation on corrosion rates. An overview of the LANSCE corrosion loop, the corrosion probes, and data from an in-beam alloy 718 probe are presented.« less
  • The ion source for the spallation neutron source (SNS) is a radio-frequency, multicusp source designed to deliver 45 mA of H2 to the SNS accelerator with a pulse length of 1 ms and repetition rate of 60 Hz. A total of three ion sources have been fabricated and commissioned at Lawrence Berkeley National Laboratory and subsequently delivered to the SNS at the Oak Ridge National Laboratory. The ion sources are currently being rotated between operation on the SNS accelerator, where they are involved in ongoing efforts to commission the SNS LINAC, and the hot spare stand (HSS), where high-current testsmore » are in progress. Commissioning work involves operating the source in a low duty-factor mode (pulse width {approx}200 ms and repetition rate {approx}5 Hz) for extended periods of time while the high-current tests involve source operation at full duty-factor of 6 percent (1 ms/60 Hz). This report discusses routine performance of the source employed in the commissioning role as well as the initial results o f high-current tests performed on the HSS.« less
  • The thermohydraulic behavior of the liquid-metal target of the spallation neutron source at Paul Scherrer Institute has been investigated. The configuration is a natural-circulation loop in a concentric double-tube-type container. The model is based on one-dimensional loop analysis, and the thermohydraulic behavior of the target liquid, as well as the total performance of the target, are studied analytically and numerically. These results are verified by two experiments using liquid metal. The results show that the natural-circulation loop concept is valid for the design phase of the target construction, and the current specified design criteria will be fulfilled with the proposedmore » parameter values.« less
  • This study examines the thermal-hydraulic issues and limitations of a water-cooled tungsten rod target for use as a compact experimental spallation neutron source. A methodology is developed to analyze the thermal hydraulics of a water-cooled rod target, and a baseline target design is evaluated at a beam power of 1 MW. The thermal-hydraulic model is then used to predict the thermal-hydraulic limits of a water-cooled tungsten rod target and to estimate the theoretical maximum power based on these limits.
  • The Spallation Neutron Source (SNS) is a high-power accelerator-based pulsed spallation source being designed by a multilaboratory team led by Oak Ridge National Laboratory to achieve high fluxes of neutrons for scientific experiments. Computational fluid dynamics (CFD) is being used to analyze the design of the SNS target. The target is subjected to the neutronic (internal) heat generation that results from the proton collisions with the mercury nuclei. The liquid mercury serves as the coolant as well as the target, and the target design must allow for heat removal from the stainless steel target enclosure. Recirculation and stagnation zones withinmore » the target are of particular concern due to the possibility that they will develop into local hot spots. These zones exist since the target design includes a complete U-turn flow redirection. Although the primary concern is that the target is adequately cooled, the target pressure drop must also be considered because it directly affects structural loading and required pumping power. The wall heat transfer is particularly important in the cooling of the window and the interior flow baffle. Another concern that has not yet been analyzed is the pulsation dynamics that occur on a microsecond timescale and affect the flow through thermal shocks. Two-dimensional CFD analysis has been completed, and the results compared favorably with spreadsheet calculations based on empirical heat transfer and pressure drop correlations, as well as with published experimental data for total pressure drop. This work has been extended to include a full three-dimensional model of the target geometry, including the liquid mercury, stainless steel pressure boundary, and supplemental liquid-mercury cooling jacket channels on the outside of the target.« less