目(mu)前(qian),我(wo)國已建(jian)和在建(jian)的二代(dai)加(jia)核(he)(he)電(dian)(dian)站以壓(ya)水(shui)堆(dui)核(he)(he)電(dian)(dian)站為主,核(he)(he)島設(she)(she)備是(shi)遵循RCC系列規(gui)范(fan),采用RCC--M壓(ya)水(shui)堆(dui)核(he)(he)島機(ji)械設(she)(she)備設(she)(she)計和建(jian)造規(gui)范(fan)。新建(jian)AP1000三代(dai)核(he)(he)電(dian)(dian)站按(an)照美國ASME核(he)(he)電(dian)(dian)規(gui)范(fan)要求,采用ASMEBPVCⅢ核(he)(he)設(she)(she)施部件建(jian)造規(gui)則。核(he)(he)電(dian)(dian)站管(guan)道系統和設(she)(she)備制(zhi)造使用的無縫不銹鋼管可分為四大類,即碳鋼/碳錳鋼/低合金鋼類、鉻鉬鋼類、不銹鋼類和鎳基合金類。核電站中不同的管道系統使用不同材質和不同核安全級別的無縫不銹鋼管。如核安全等級1級、2級、3級、非核級材料,其質量等級別分別對應RCC--M規范Q1、Q2、Q3、QNC級和ASMEBPVCⅢ規范A、B、C、D級,其生產制造和質保要求均嚴格按照規范的相關規定執行,核1、2、3級產品的生產制造活動還需要向國家核安全局申報、備案,并接受監管。
不(bu)銹(xiu)(xiu)鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)材(cai)(cai)質特點(dian)及選(xuan)材(cai)(cai)要(yao)求:核(he)電(dian)(dian)站核(he)島回(hui)路系(xi)統(tong)由于要(yao)將放射性物質包容在其(qi)內,管(guan)(guan)(guan)(guan)(guan)道(dao)(dao)材(cai)(cai)料選(xuan)擇(ze)要(yao)求考慮運行工況(kuang)、冷(leng)卻劑介質、材(cai)(cai)料老(lao)化等多種因素(su)。如(ru)核(he)蒸汽系(xi)統(tong)輸出堆芯(xin)熱能的主管(guan)(guan)(guan)(guan)(guan)道(dao)(dao),是連(lian)接反應堆壓力容器(qi)(qi)和蒸汽發生器(qi)(qi)的特厚壁承壓管(guan)(guan)(guan)(guan)(guan)道(dao)(dao),屬核(he)一級關(guan)鍵設備,目前二代核(he)電(dian)(dian)機(ji)組采(cai)用(yong)奧氏(shi)體--鐵素(su)體雙相不(bu)銹(xiu)(xiu)鋼(gang)(gang)離心(xin)鑄管(guan)(guan)(guan)(guan)(guan),而三代核(he)電(dian)(dian)AP1000機(ji)組則采(cai)用(yong)超低碳控(kong)氮不(bu)銹(xiu)(xiu)鋼(gang)(gang)整體鍛造工藝制造,其(qi)技術(shu)難度非常高;與(yu)冷(leng)卻劑相關(guan)的一回(hui)路管(guan)(guan)(guan)(guan)(guan)道(dao)(dao)系(xi)統(tong)采(cai)用(yong)不(bu)含(han)Mo的304不(bu)銹(xiu)(xiu)鋼(gang)(gang)、含(han)Mo的316L不(bu)銹(xiu)(xiu)鋼(gang)(gang)及時(shi)效硬化型奧氏(shi)體不(bu)銹(xiu)(xiu)鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan);蒸汽發生器(qi)(qi)的傳熱管(guan)(guan)(guan)(guan)(guan)要(yao)求強韌性和耐(nai)應力腐蝕能力,通常采(cai)用(yong)Inconel600和Inconel690的鎳基(ji)合金管(guan)(guan)(guan)(guan)(guan);對于核(he)蒸汽系(xi)統(tong)和核(he)輔助(zhu)系(xi)統(tong)管(guan)(guan)(guan)(guan)(guan)道(dao)(dao)(NSSS和BNI)則一般采(cai)用(yong)碳鋼(gang)(gang)/碳錳鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan),如(ru)TUE250B、TU42C、P280GH(TU48C)、A106BP11Gr6等。
常(chang)規(gui)島管(guan)(guan)(guan)(guan)道(dao)二回路管(guan)(guan)(guan)(guan)道(dao)系(xi)(xi)統(tong)主要是(shi)輸(shu)送蒸汽(qi)和給水,整個(ge)系(xi)(xi)統(tong)輸(shu)送的介質(zhi)溫度(du)、壓(ya)力參(can)數均比同功率火電(dian)機組低,沒有高溫蠕變問題,因此常(chang)規(gui)島二回路管(guan)(guan)(guan)(guan)道(dao)系(xi)(xi)統(tong)用(yong)(yong)(yong)鋼(gang)(gang)管(guan)(guan)(guan)(guan)采(cai)用(yong)(yong)(yong)碳/碳錳鋼(gang)(gang)。但是(shi),因為該管(guan)(guan)(guan)(guan)道(dao)系(xi)(xi)統(tong)輸(shu)送帶(dai)一定濕度(du)的飽和蒸汽(qi),存在“流動(dong)加速的腐蝕(FAC)問題,這會間接(jie)影響整個(ge)電(dian)站的安全(quan)。對于存在流體加速腐蝕(FAC)的管(guan)(guan)(guan)(guan)道(dao)材料(liao),要求選(xuan)擇能夠抑制FAC現象的控碳/錳鋼(gang)(gang),如控鉻20鋼(gang)(gang)、控鉻A106/API5LB等;對于蒸汽(qi)濕度(du)較大(da)的高壓(ya)缸排汽(qi)管(guan)(guan)(guan)(guan)線(xian)和高壓(ya)加熱器(qi)的抽(chou)汽(qi)管(guan)(guan)(guan)(guan),直接(jie)選(xuan)用(yong)(yong)(yong)鉻含量較高的合金(jin)鋼(gang)(gang)管(guan)(guan)(guan)(guan),如A355P11、P22等;對同時(shi)抗“FAC”和抗疲勞的蒸汽(qi)輸(shu)水管(guan)(guan)(guan)(guan)線(xian),則選(xuan)用(yong)(yong)(yong)304L不銹鋼(gang)(gang)管(guan)(guan)(guan)(guan)。