FISRE special report: Insulation resistance of electronic circuits in smoke - quantification of the problem and needed countermeasures

Johan Mangs, Olavi Keski-Rahkonen, Mika Letonsaari

Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

Abstract

Acute effects of smoke on insulation resistance of electronics used in programmable automation circuitry in nuclear power plants were studied experimentally. Real and mock-up circuitry was exposed to smoke in four tests. Relevant physical parameters of smoke and electrical performance of circuitry was measured online for a period of an hour. It was noticed that insulation resistance decreased by three orders of magnitude due to soot deposits on surfaces on uncoated circuitry. For real commercial circuits, coated by a protective lacquer layer, no electrical changes were observed. A quantitative model for smoke exposure and deposition on surfaces is proposed based on existing physical models of aerosols. A consistent picture of the relevant processes was found, and an easy calculation method for smoke hazard estimation for PSA-work is proposed for insulation resistance deterioration. This model allows also estimation of the required performance of protective coatings to prevent parasitic leakage currents between different parts of circuitry.
Original languageEnglish
Title of host publicationFINNUS: The Finnish Research Programme on Nuclear Power Plant Safety
Subtitle of host publicationInterim Report 1999 - August 2000
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages192-202
ISBN (Electronic)951-38-5751-4
ISBN (Print)951-38-5750-7
Publication statusPublished - 2000
MoE publication typeD2 Article in professional manuals or guides or professional information systems or text book material

Publication series

SeriesVTT Tiedotteita - Research Notes
Number2057
ISSN1235-0605

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    Mangs, J., Keski-Rahkonen, O., & Letonsaari, M. (2000). FISRE special report: Insulation resistance of electronic circuits in smoke - quantification of the problem and needed countermeasures. In FINNUS: The Finnish Research Programme on Nuclear Power Plant Safety: Interim Report 1999 - August 2000 (pp. 192-202). VTT Technical Research Centre of Finland. VTT Tiedotteita - Research Notes, No. 2057 http://www.vtt.fi/inf/pdf/tiedotteet/2000/T2057.pdf