Monitoring pipes for residual alpha contamination
- Los Alamos National Lab., NM (United States)
- BNFL Instruments Ltd., Cumbria (United Kingdom)
The sensitivity and application of traditional alpha monitors is limited by the short range of alpha particles in air (typically 10 cm) and in solid materials (typically tens of {mu}m). Detecting small amounts of alpha-emitting contamination inside pipes presents particular problems. The alpha particle cannot penetrate the walls of the pipe. Associated gamma-ray detection and active neutron interrogation is often used to detect large amounts of radioactive material in pipes, but these methods are of limited use for detecting small amounts of contamination. Insertion of traditional alpha probes works well in large-diameter straight, pipes, but is increasingly difficult as the pipe network becomes smaller in diameter and more complex. Monitors based on long-range alpha detection (LRAD) detect ionization of the ambient air rather than the alpha particles themselves. A small fan draws the ions into an externally mounted ion detector. Thus, the air in the pipe serves as both the detector gas and the mechanism for transporting the alpha-induced ions to a detection grid outside of the pipe. All of the ions created by all of the contamination in the pipe can be measured in a single detector. Since ambient air serves as the {open_quotes}probe,{close_quotes} crushed or twisted sections of pipe can be monitored almost as effectively as straight sections. The pipe monitoring system described in this paper was tested both at Los Alamos and at BNFL`s Sellafield reprocessing facility in the UK. In this paper, the authors report on the first field tests of the pipe monitoring system.
- OSTI ID:
- 474032
- Report Number(s):
- CONF-960804-Vol.2; TRN: 97:008783
- Resource Relation:
- Conference: SPECTRUM `96: international conference on nuclear and hazardous waste management, Seattle, WA (United States), 18-23 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the international topical meeting on nuclear and hazardous waste management (SPECTRM `96): Volume 2; PB: 875 p.
- Country of Publication:
- United States
- Language:
- English
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