05000324/FIN-2018011-03
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Finding | |
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Title | Potential Unjustified Activation Energy for Rosemont Transmitters |
Description | The licensee used 0.78 eV as the limiting activation energy for Rosemount transmitters. The activation energy was based upon an academic paper documenting experimental work performed for the early space program and first published in 1965. The paper cautioned the reader that the methods used were experimental and were not validated. A 0.5 eV activation energy for electronics was documented by the Electric Power Research Institute (EPRI) report NP-1558, which attributed it to electron migration of aluminum. Reports published by the Institute of Electrical and Electronics Engineers (IEEE) indicated that activation energies for various electronics and their failure modes could range from 0.5-0.66 eV. The licensee did not document an independent failure modes and effects analysis to justify the activation energy that they used. In addition, the licensee chose to use less limiting activation energies that were not proven to be justified. Finally, the licensee was unable to demonstrate acceptable margins for extrapolation confidence. The IEEE standard 323-1974, section 6.5.2, Mathematical Modeling, stated, the first step in the qualification by analysis is generally the construction of a valid mathematical model of the electric equipment to be qualified. The mathematical model shall be based upon established principles, verifiable test data, or operating experience data. The mathematical model shall be such that the performance of the electric equipment is a function of time and the pertinent environmental parameters. All environmental parameters listed in the equipment specification must be accounted for in the construction of the mathematical model unless it can be shown that the effects of the parameter of interest are dependent on the effects of the remaining environmental parameters. Planned Closure Actions: The team must determine whether the activation energy used for the transmitters was appropriate and, if not, whether the licensee had the responsibility to verify the information provided by their vendors and contractors. The region is discussing this issue with NRC headquarters to find a resolution to this issue. |
Site: | Brunswick ![]() |
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Report | IR 05000324/2018011 Section 1R21 |
Date counted | Jun 30, 2018 (2018Q2) |
Type: | URI: |
cornerstone | Mitigating Systems |
Identified by: | Licensee-identified |
Inspection Procedure: | IP 71111.21N |
Inspectors (proximate) | E Stamm T Fanelli T Su M Sykes |
INPO aspect | |
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Finding - Brunswick - IR 05000324/2018011 | |||||||||||||||||||||||||||||||||||||||||
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Finding List (Brunswick) @ 2018Q2
Self-Identified List (Brunswick)
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