Experimental Studies on Role of Scattering Centers on Wave Energy Attenuation

Conference · Sun Jun 18 04:00:00 EDT 2000

OSTI ID:755663

Kim, S H ^[1]; Knaff, C L; Taleyarkhan, R P

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1. ORNL

In accelerator-driven neutron sources such as the Spallation Neutron Source (SNS) with powers in the 2 MW range (time-averaged), the interaction of the energetic proton beam with the mercury target can lead to very high heating rates in the target. Although the resulting temperature rise is relatively small (a few C), the rate of temperature rise is enormous (ca.10{sup 7} C/s) during the very brief beam pulse (-0.58 ps). The resulting thermal-shock induced compression of the mercury leads to the production of large amplitude pressure waves in the mercury that interact with the walls of the mercury target and the bulk flow field. Understanding and predicting propagation of pressure pulses in the target are considered critical for establishing the feasibility of constructing and safely operating such devices. Safety-related operational concerns exist in two main areas, viz., (1) possible target enclosure failure from impact of thermal shocks on the wall due to its direct heating from the proton beam and the loads transferred from the mercury compression waves, and (2) impact of the compression-cumrarefaction wave-induced effects such as cavitation bubble emanation and fluid surging. Preliminary stress evaluations indicate stress levels approaching yielding conditions and beyond in selected regions of the target. Also, the induction of cavitation (that could assist in attenuation) can also release gases that may accumulate at undesirable locations and impair heat transfer.

• Research Organization: Oak Ridge National Lab., TN (US)
• Sponsoring Organization: USDOE Office of Science (US)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 755663
• Report Number(s): ORNL/CP-106495
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
COMPRESSION
FAILURES
HEATING RATE
MERCURY
NEUTRON SOURCES
PROTON BEAMS
SPALLATION
TARGETS
THERMAL SHOCK
THERMAL STRESSES