The　long-term　irregular　vibration　of　small　branches　in　the　complex　pipelines　of　nuclear　power　units　can　lead　to　fatigue　fracture　and　damage,　causing　leaks　and　even　nuclear　safety　accidents.　Currently,　reinforcement　or　vibration　reduction　methods　are　commonly　used,　but　the　effectiveness　is　limited,　and　reducing　the　vibration　peak　at　certain　frequencies　is　challenging.　To　address　these　issues,　this　paper　proposes　the　design　of　a　structurally　simple,　easy-to-install,　and　adjustable-quality　dynamic　absorber.　By　simulating　actual　vibration　conditions,　the　dynamic　modeling　and　analysis　of　small　branches　with　and　without　dynamic　absorbers　are　conducted.　Using　the　acceleration　transfer　rate　as　a　reference,　the　relevant　parameters　of　the　dynamic　absorber　are　designed　to　obtain　the　optimal　mass,　stiffness,　and　damping　of　the　dynamic　absorber.　Finally,　the　physical　prototype　is　produced　and　experimentally　verified.　The　results　show　that　the　designed　dynamic　absorber　in　this　paper　reduces　the　three-axis　vibration　of　small　branches　at　resonance　frequencies　by　more　than　60%　(exceeding　the　engineering　requirement　of　5　dB).　Fine-tuning　the　number　of　mass　blocks　expands　the　adjustable　range　of　the　absorption　frequency　band,　meeting　the　requirements　of　different　operating　conditions.　Adding　metal　rubber　material　further　enhances　the　absorption　effect　of　the　dynamic　absorber,　improving　the　damping　performance　by　more　than　10%　compared　to　the　structure　without　damping.　This　research　provides　an　effective　method　for　vibration　reduction　in　the　small　branches　of　complex　pipelines　in　nuclear　power　units.　©　2024　Atomic　Energy　Press.　All　rights　reserved.