Tuned　mass　damper　(TMD)　has　been　applied　in　civil　engineering　fields　to　reduce　the　seismic　response.　However,　few　TMDs　are　used　in　the　nuclear　structure　due　to　the　huge　additional　mass　of　the　traditional　TMD　device　on　the　nuclear　structure.　In　this　paper,　the　PCS　water　tank　of　a　nuclear　structure　is　reconstructed　into　a　TMD　system　to　reduce　the　seismic　response　of　the　nuclear　structure.　The　proposed　novel　water　tank-TMD　device　can　use　its　characteristics　of　large　mass　to　achieve　the　tuned　shock　absorption　effectively　while　maintaining　the　original　function　of　the　water　tank.　Moreover,　more　and　more　nuclear　power　structures　are　being　built　on　non-bedrock　sites,　and　the　effects　of　soil-structure　interaction　(SSI)　on　the　seismic　response　and　seismic　migration　performance　of　nuclear　power　structures　need　to　be　reasonably　considered.　The　effects　of　SSI　and　auxiliary　plants　on　the　seismic　response　of　the　nuclear　containment　plants　equipped　with　PCS　water　tanks　are　first　investigated.　Subsequently,　the　performance　of　the　water　tank-TMD　system　in　reducing　the　seismic　responses　of　nuclear　containment　plants　is　analyzed　in　detail　by　considering　the　effect　of　SSI,　design　frequency　of　TMD,　and　design　criteria　of　TMD.　The　research　results　show　that　the　proposed　water　tank-TMD　system　can　effectively　reduce　the　seismic　response　of　nuclear　containment　plants.　Besides,　it　is　necessary　to　consider　the　influence　of　SSI　on　the　dynamic　characteristics　of　the　structure　in　the　design　of　TMD　when　the　SSI　effect　is　strong.　The　water　tank-TMD　system　designed　according　to　the　TMD　criteria　proposed　by　Sadek　et　al.,　and　Salvi　and　Rizzi　has　better　reduction　performance　compared　with　that　designed　by　other　design　criteria.　©　2024