SONIC METHODS FOR P.F.R. CHANNEL BLOCKAGE DETECTION

Technical Report · Tue Oct 29 04:00:00 EST 1963

OSTI ID:4539674

Walton, A J

Channel blocking in a PFR sub-assembly may lead to loss of coolant flow and hence to boiling in the sodium. Acoustics offers the possibilities of two methods for the detection of the presence of bubbles arising from the coolant boiling. Blockage detection by 'listening' is feasible, provided that the noise produced by boiling can be distinguished from the background, by transducers placed at the most suitable points in the system. Experimental work shows that wide-band noise is produced when vapour bubbles from a heated surface collapse upon entry into a sub-cooled region. Gas bubbles, which are also produced by boiling in water containing air, or sodium containing argon, act as resonators at frequencies inversely proportional to their size. The resultant noise spectrum, due to boiling at a heated surface in a vessel containing water, covers the audio frequency range but the shape depends on the number and size of air bubbles present. It is further modified by the geometry of the vessel in which boiling takes place. Boiling in static sodium is likely to produce very similar noise. Flow will reduce the size of bubbles formed, so that resonances are at higher frequencies where the wide-band energy is less. Further work is proposed to investigate (1) The noise from boiling sodium in a blocked sub-assembly; (2) The likely background noise in the PFR; and (3) Transducer design and development for operation in the PFR environment. Blockage detection by change of velocity or attenuation of sound due to the presence of bubbles of gas or vapour is not practical in the context of the present PFR design. (auth)

• Research Organization: Reactor Group, United Kingdom Atomic Energy Authority, Risley, England (United Kingdom)
• NSA Number: NSA-20-028763
• OSTI ID: 4539674
• Report Number(s): TRG-Report-665
• Country of Publication: United Kingdom
• Language: English

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