This research is to investigate the feasibility and practicability of carrying out an experimental work to support the seismic assessment of High Temperature Reactor Pebble bed Module (HTR-PM) reactor graphite core structure, which contains thousands of graphite bricks and tens of thousands of keys/dowels. The seismic responses of HTR-PM reactor under the seismic and impact conditions are beyond the applicability of the analytical methods currently employed, and the experimental program would be required to enhance the development of alternative analytical method and extensions of the current methods. This work can provide information and judgments for potential future work that would be nuclear safety related. The seismic excitations applied on the 1:2 double-layer graphite core model without side and top metallic components support, which is part of HTR-PM side reflector structure, included: (a) the white noise excitation from 0.1g to 0.5g amplitude in two orthogonal directions; (b) sine-sweep, frequency band from 1.0 to 35.0 back to 1.0 Hz, sweep rates less than 2 oct/min while 1 oct/min around resonant frequencies, at constant 0.5g amplitude in one horizontal uniaxial excitation; (c) five OBEs (Operating Basis Earthquake) up to 7.4g and (d) one SSE (Safe Shutdown Earthquake) up to 8.0g by considering scale law; (e) Four similar models have been tested with different gaps (1.6, 3.0 and 5.0mm) between bricks and with/without holddown plates, which can indicate approximately core structure characteristic at different lifetime for graphite irradiation deformation. The response of acceleration and displacement are measured in the tests. The natural frequencies of double layers model, bricks radial and tangential relative displacement have been calculated from the test results. Damaged graphite components have been counted and analyzed. The purpose of the test is to (a) investigate model dynamic behavior and response characteristics of integrated graphite components, (b) verify model scaling laws; (b) provide specific data on bricks relative displacement, acceleration; (c) provide data for correlation with analytical models; (d) verify the seismic analysis code to be developed in INET, and (e) optimize the detail design for HTR-PM project. The preliminary simulation results achieved good agreement with the data obtained from the test.

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