AA.4351 General
Design vcrification by testing shall be in accordance with the rules of this subarticle. Seismic tests are to be performed by subjecting the equipment to vibratory motion that conservatively simulates that postulated at the equipment mouiflmg during the OHE and an SSE. In addition, other loads that may occur concurrently with the seismic event shall be accounted for (see AA4212). The rules of this suharticle are consistent with and complementary to ANSI/IEEE 344.
AA-4351.1 Equlpmciit Mounting. The equipment to be tested shall be mounted on the test machine in a manner that simulates the intended service mounting. The mounting method shall be the same as that recommended for actual service, which includes the recommended bolt sue and configuration, weld pattern, and type. The effect of all attached hardware such as electrical connections, conduit, sensing lincs,piping. and ductwork shall be considered. The method of mounting the equipment to the test machine shall be documented and shall include a description of any interposing IIxtures and connections. ElTect of such fixtures and connections shall be evaluated if they are only used during qualification and not for inservice mounting. Equipment orientation shall be along the major and minor axes for each test condition unless specified otherwise by the equipment design specification or the applicable equipment section of this Code.
AA-435I.2 Equipment Monitoring. SuIficien morntoring equipment shall be used to evaluate the performance of the safety function of the equipment before. during, and after the test. In addition, sufficient vibration monitoring equipment shall he used to allow determination of the applied vibration levels. In addition to the monitoring of the test machine, as many points of the equipment shall be monitored as needed to provide information for evaluating the test results.
AA-4351.3 Exploratory Tests. Exploratory vibration tests required for all qualification tests except multiple frequency tests (see AA-4356) shall be run on equipment to aid in the determination of the test method that will best qualify or determine the dynamic characteristics of the equipment. As per AA-4352, the type of test required to qualify equipment for various applications shall be dependent on the nature and dynamic character. istics of the equipment and the required response spectrum (RRS). If it can be shown that the equipment is not in resonance at any frequency within the frequency
(a) bandwidth of the RRS compared to that of the TRS and equipment characteristics and responses:
(b) duration of the test compared to the defined seismic event;
(c) peak acceleration of the test input and the ampli. tication observed;
(d) natural modes and frequencies of vibration of the equipment:
(t) typical damping of the equipment:
f) fragility levels: and
(g) total number of cycles and the simulation of fatigue failure.
AA4357 Test Duration
The number of required OBE events per 40-year- plant-life shall be a minimum of five unless stated otherwise in the equipment design specification.
The number of tests run as proof tests (see AA4351.6) shall have an appropriate input level to fulfill the requirements of AA-4351.4. The OBE tests shall be followed by at least one SSE test. The duration of each test shall at least equal the strong motion portion of the original time history used to obtain the RRS for the SSE and shall be a minimum of 3() see for a multifrequency test, and a minimum of 15 sec for a single frequency test. Credit may be taken for any test preceding the SSE test if it is shown to be greater than or equal in severity to the required OBEx. Fragility test durations shall at least equal the time duration tr the strong motion portion of the SSE in order to properly account for vibration buildup.
AA-4358 Simigle- and Nlultiaxis Tests
Single-axis tests are permitted if the tests are designed to reflect conservatively the seismic event at the equipment mounting locations, or if the equipment being tested can be shown to respond independently in each of the three orthogonal axes or otherwise withstand the seismic event at its mounting location. This is the case if equipment axis coupling is iero or very low. For example. if a device is normally mounted on a panel that amplifies motion in one direction, or if a device is restrained to have motion in one direction. single-axis testing of the device is permitted.
If the preceding considerations do not apply, multiaxis testing shall be used. The minimum is biaxial testing with simultaneous inputs in a principal horizontal axis and the vertical axis. Independent random inputs are preferred and.