某核電廠18PA6B柴油機發(fā)生連桿螺栓斷裂事故失效原因分析與研究

摘" 要：某核電廠備用柴油發(fā)電機組A列按計劃執(zhí)行設(shè)備季度試驗（滿功率試驗）過程中，A8缸活塞連桿螺栓斷裂，連桿飛出擊破A8缸曲軸箱蓋板，伴隨大量潤滑油及冷卻水泄漏，現(xiàn)場人員立即緊急停機干預(yù)，柴油發(fā)電機停機。針對此次事件，該文結(jié)合事故后受損零部件的檢驗報告開展連桿螺栓斷裂原因分析，其中A8-1和A8-2連桿螺栓分別有1處和2處斷口，A8-1連桿螺栓斷口和A8-2連桿螺栓斷口1的斷口形貌均為雙向彎曲疲勞斷裂，A8-2連桿螺栓斷口2的斷口形貌為彎曲過載斷裂。通過斷口形貌及柴油發(fā)電機運行情況，可以判斷出連桿螺母松退導(dǎo)致A8-1和A8-2連桿螺栓斷口1發(fā)生雙向彎曲疲勞斷裂，從而引起其他部件損壞。最后，為避免該類型事件發(fā)生，提出一些建議。

關(guān)鍵詞：柴油發(fā)電機組；連桿螺栓；失效原因分析；斷口；螺母

中圖分類號：TM623" " "文獻(xiàn)標(biāo)志碼：A" " " " " 文章編號：2095-2945（2024）33-0005-04

Abstract： During the quarterly equipment test（full power test） of the spare diesel generator set of a nuclear power plant as planned， the piston connecting rod bolt of cylinder A8 broke， and the connecting rod flew out and broke the crankcase cover plate of cylinder A8. Accompanied by the leakage of a large amount of lubricating oil and cooling water， on-site personnel immediately stopped the emergency and intervened， and the diesel generator was shut down. In response to this incident， this paper analyzes the causes of the connecting rod bolt fractures based on the inspection reports of damaged parts after the accident. Among them， the A8-1 and A8-2 connecting rod bolts have 1 and 2 fractures respectively. The fracture morphology of the A8-1 connecting rod bolt fracture and the A8-2 connecting rod bolt fracture 1 are both bidirectional bending fatigue fractures， and the fracture morphology of the A8-2 connecting rod bolt fracture 2 is bending overload fracture. Through the fracture morphology and the operating conditions of the diesel generator， it can be determined that the loosening of the connecting rod nuts causes the two-way bending fatigue fracture of the A8-1 and A8-2 connecting rod bolts" fracture 1， which causes damage to other components. Finally， some suggestions are put forward to avoid this type of incident.

Keywords： diesel generator set; connecting rod bolt; failure cause analysis; fracture; nut

2019年1月12日，某核電廠備用柴油發(fā)電機組A列按計劃執(zhí)行設(shè)備季度試驗（滿功率試驗）過程中，A8缸活塞連桿螺栓斷裂，連桿飛出擊破A8缸曲軸箱蓋板，伴隨大量潤滑油及冷卻水泄漏，現(xiàn)場人員立即緊急停機干預(yù)，柴油發(fā)電機停機。

故障柴油機型號為18PA6B，該類型柴油機是在法國熱機協(xié)會（S.E.M.T）PA6型柴油機的基礎(chǔ)上通過增加行程、匹配高效增壓器、重新設(shè)計噴油系統(tǒng)等而研發(fā)的新一代高性能中高速柴油機（圖1）。

柴油機由兩大機構(gòu)和四大系統(tǒng)組成：兩大機構(gòu)是指曲柄連桿機構(gòu)和配氣機構(gòu)；四大系統(tǒng)是指啟動空氣系統(tǒng)、潤滑油系統(tǒng)、高/低溫水冷卻系統(tǒng)和燃油系統(tǒng)?！?br>