Interpretations

Answering questions that may arise related to the meaning of portions of an IEEE standard concerning specific applications.

IEEE Standards Interpretation for IEEE Std 344™-1987 IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations

Copyright © 2002 by the Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue New York, New York 10016-5997 USA All Rights Reserved.

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November 2002

Interpretation Request #1
Topic: Design Life of a Nuclear Power Plant (Equipment Qualification Department) Relevant Clause: Subclause 7.1.5.2

In 7.1.5.2 of IEEE Std 344 -1987, 7.1.5.2, Seismic Aging (OBE), there is following sentence:

"The number of OBE shall be justified for each site or shall produce the equivalent effect of five OBE."

Please interpret the above sentence as to whether 5 OBEs could be applied when design life of a nuclear power plant, especially the equipment qualification department, is increased from 40 to 60 years.

Interpretation Response
IEEE Std 344 states only that the number of OBEs should be justified or shall produce the equivalent of 5 OBEs. The number of OBE occurrences for a specified design life of the nuclear power plant is not specified. The OBE tests preceding the SSE are performed to seismically age (fatigue) the test specimen. Determination of how many OBE occurrences are appropriate for a particular site over its design life is the responsibility of the Owner or the Owner's designee, subject to regulatory agency approval.