Environmental tests of a digital safety channel: An investigation of stress-related vulnerabilities of computer-based safety system

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Nuclear Safety

OSTI ID:642364

Korsah, K; Wilson, T L; Wood, R ^[1]; Tanaka, T ^[2]

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1. Oak Ridge National Lab., TN (United States)
2. Sandia National Labs., Albuquerque, NM (United States)

This article presents the results of environmental stress tests performed on an experimental digital safety channel (EDSC) assembled at the Oak Ridge National Laboratory as part of the Qualification of Advanced Instrumentation and Controls Systems Research program, which was sponsored by the US Nuclear Regulatory Commission. The program is expected to provide recommendations for environmental qualification of digital safety systems. The purpose of the study was to investigate potential vulnerabilities of distributed computer systems used in safety applications when subjected to environmental stressors. The EDSC assembled for the tests employs technologies and digital subsystems representative of those proposed for use in advanced light-water reactors or as retrofits in existing plants. Subsystems include computers, electrical and optical serial communication links, fiber-optic network links, analog-to-digital and digital-to-analog converters, and multiplexers. The EDSC was subjected to selected stressors that are a potential risk to digital equipment in a mild environment. The selected stressors were electromagnetic and radiofrequency interferences (EMI-RFI), temperature, humidity, and smoke exposure. The stressors were applied at levels of intensity considerably higher than the safety channel is likely to experience in a normal nuclear power plant environment. Ranges of stress were selected at a sufficiently high level to induce errors so that failure modes that are characteristic of the technologies employed could be identified. On the basis of the incidence of functional errors observed during testing, EMI-RFI, smoke exposure, and high temperature coupled with high relative humidity, in that order, were found to have the greatest impact of the stressors investigated. The most prevalent stressor-induced upsets, as well as the most severe, were found to occur during the EMI-RFI tests.

• Sponsoring Organization: Nuclear Regulatory Commission, Washington, DC (United States); USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 642364
• Journal Information: Nuclear Safety, Journal Name: Nuclear Safety Journal Issue: 1 Vol. 38; ISSN 0029-5604; ISSN NUSAAZ
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
22 GENERAL STUDIES OF NUCLEAR REACTORS
ANALOG-TO-DIGITAL CONVERTERS
CERTIFICATION
COMPUTERS
DATA TRANSMISSION SYSTEMS
DIGITAL SYSTEMS
DIGITAL-TO-ANALOG CONVERTERS
ENGINEERED SAFETY SYSTEMS
HUMIDITY
INTERFERENCE
MULTIPLEXERS
OPTICAL FIBERS
REACTOR CONTROL SYSTEMS
SMOKES
TEMPERATURE DEPENDENCE