Status of R&D on mitigating the effects of pressure waves for the Spallation Neutron Source mercury target

Autor: Mark W Wendel, David K Felde, Ashraf A Abdou, David A McClintock, Bernie Riemer
Rok vydání: 2012
Předmět:
Zdroj: Journal of Nuclear Materials. 431:160-171
ISSN: 0022-3115
DOI: 10.1016/j.jnucmat.2011.11.018
Popis: The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory has been conducting RD and protective gas walls that isolate the vessel from the damaging effects of collapsing cavitation bubbles. The latter has demonstrated good damage mitigation during in-beam testing with limited pulses, and adequate gas wall coverage at the beam entrance window has been demonstrated with the SNS mercury target flow configuration using a full scale mercury test loop. A question on the required area coverage remains which depends on results from SNS target post irradiation examination. The small gas bubble technique has been less effective during past in-beam tests but those results were with un-optimized and un-verified bubble populations. Another round of in-beam tests with small gas bubbles is planned for 2011. The first SNS target was removed from service in mid 2009 and samples were cut from two locations at the target’s beam entrance window. Through-wall damage was observed at the innermost mercury vessel wall (not a containment wall). The damage pattern suggested correlation with the local mercury flow condition which is nearly stagnant at the peak damage location. Detailed post irradiation examination of the samples is under way that will assess the erosion and measure irradiation-induced changes in mechanical properties. Similar samples were cut from the second SNS target after it was removed from service in mid 2010. More extensive damage was observed on the target inner wall but damage to the containment wall was minimal.
Databáze: OpenAIRE
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