Lalatattun bawuloli a cikin tsarin gaggawa na tashar wutar lantarki ta LaSalle

A wannan bazarar, Ƙungiyar Binciken Musamman na NRC (SIT) ta gudanar da wani bincike na Kamfanin Lantarki na LaSalle don bincikar dalilin rashin nasarar bawul da kuma kimanta tasirin matakan gyara da aka ɗauka. Raka'a biyu na Kamfanin Lantarki na Nukiliya na LaSalle County na Exelon Generation, kimanin mil 11 kudu maso gabas da Ottawa, Illinois, masu tafasa ruwa ne (BWR) waɗanda suka fara aiki a farkon 1980s. Kodayake yawancin BWRs da ke aiki a Amurka sune BWR/4 tare da ƙirar alamar Mark I, "sabbin" na'urorin LaSalle suna amfani da BWR/5 tare da ƙirar alamar Mark II. Babban bambanci a cikin wannan bita shi ne cewa ko da yake BWR/4 yana amfani da tsarin allurar sanyaya mai ƙarfi mai ƙarfi (HPCI) don samar da ƙarin ruwa mai sanyaya zuwa core reactor lokacin da ƙaramin bututun da ke haɗa jirgin ruwa ya fashe, BWR/5 yana amfani da tsarin Babban Matsakaicin Matsakaicin Matsala (HPCS) don cimma wannan aikin aminci. Ranar Fabrairu 11, 2017, bayan tsarin kulawa da gwaji, ma'aikata sun yi ƙoƙari su sake cika tsarin No. 2 high-pressure core injection (HPCS). A wancan lokacin, an rufe reactor na Unit 2 saboda katsewar man fetur, kuma an yi amfani da lokacin ragewa don duba tsarin gaggawa, kamar tsarin HPCS. Tsarin HPCS galibi yana cikin yanayin jiran aiki yayin aikin reactor. An sanye da tsarin tare da famfo mai tuƙa da mota wanda zai iya samar da ƙarin ƙayyadaddun ƙayyadaddun kwarara na galan 7,000 a cikin minti ɗaya don jirgin ruwa. Famfu na HPCS yana zana ruwa daga tankin da ke cikin abun ciki. Idan karamin diamita bututu da aka haɗa da jirgin ruwan reactor ya karye, ruwan sanyaya zai zubo, amma matsin lamba a cikin jirgin ruwa yana aiki da jerin ƙananan tsarin gaggawa na gaggawa (watau zubar da zafi mai ƙazanta da ƙarancin matsi na core spray famfo. ). Ruwan da ke fitowa daga ƙarshen bututun da ya karye yana fitar da shi zuwa tankin kashewa don sake amfani da shi. Ana iya kunna famfon na HPCS da ke tuka mota daga grid ɗin da ba a buɗe ba lokacin da yake samuwa, ko kuma daga injin janareta na diesel na gaggawa lokacin da ba a samu grid ba. Ma'aikata sun kasa cika bututun da ke tsakanin bututun allura na HPCS (1E22-F004) da jirgin ruwan reactor. Sun gano cewa an raba fayafai daga tushen bawul ɗin gate mai ɗaure biyu da Anchor Darling ya yi, wanda ya toshe hanyar bututun mai. Bawul ɗin alluran HPCS wani bawul ɗin lantarki ne wanda aka saba rufewa wanda ke buɗewa lokacin da aka fara tsarin HPCS don samar da tashar ruwan gyara don isa jirgin ruwa. Motar tana amfani da juzu'i don jujjuya tushen bawul ɗin karkace don ɗaga (buɗe) ko ƙasa (kusa) diski a cikin bawul. Lokacin da aka sauke cikakke, diski zai toshe magudanar ruwa ta bawul. Lokacin da bawul ɗin ya tashi sosai, ruwan da ke gudana ta hanyar bawul yana gudana ba tare da tsangwama ba. Tun da diski ya rabu da bawul ɗin bawul a cikin wani wuri mai saukarwa sosai, motar na iya jujjuya tushen bawul ɗin kamar yana ɗaga diski, amma diski ɗin ba zai motsa ba. Ma'aikata sun ɗauki hotunan fayafai biyu da suka rabu bayan cire murfin bawul (hannun hannu) na bawul (Hoto 3). Ƙashin ƙasa na tushe yana bayyana a tsakiyar tsakiyar hoton. Kuna iya ganin fayafai guda biyu da ginshiƙan jagora tare da su (lokacin da aka haɗa su da tushen bawul). Ma'aikatan sun maye gurbin sassan ciki na bawul ɗin allurar HPCS tare da sassan da mai sayarwa ya sake tsarawa, kuma sun sake maimaita sashin No. 2. Hukumar Basin Kogin Tennessee ta gabatar da rahoto ga NRC a cikin Janairu 2013 a ƙarƙashin 10 CFR Sashe na 21 game da lahani a cikin bawul ɗin ƙofar fayafai biyu na Anchor Darling a cikin tsarin allurar sanyaya mai ƙarfi na Kamfanin Wutar Nukiliya ta Browns Ferry. A wata mai zuwa, mai ba da bawul ɗin ya ƙaddamar da rahoton 10 CFR Sashe na 21 ga NRC game da matsalar ƙira na bawul ɗin ƙofar fayafai biyu na Anchor Darling, wanda zai iya haifar da tushen bawul ɗin ya rabu da diski. A cikin Afrilu 2013, Rukunin Masu Ruwa na Ruwa na Tafasa sun ba da rahoto kan rahoton Sashe na 21 ga membobinta da kuma shawarwarin hanyoyin da za a bi don sa ido kan aiki na bawuloli da abin ya shafa. Shawarwari sun haɗa da gwaje-gwajen bincike da saka idanu jujjuyawar tushe. A cikin 2015, ma'aikata sun yi gwaje-gwajen gwajin gwaji akan HPCS allurar valve 2E22-F004 a LaSalle, amma ba a sami matsalolin aiki ba. A ranar 8 ga Fabrairu, 2017, ma'aikata sun yi amfani da jagorar sa ido kan jujjuyawa don kulawa da gwada bawul ɗin allurar HPCS 2E22-F004. A watan Afrilun 2016, ƙungiyar masu sarrafa ruwan tafasa sun sake duba rahotonsu bisa bayanin da wani mai tashar wutar lantarki ya bayar. Ma'aikata sun kwakkwance 26 Anchor Darling bawul ɗin fayafai biyu waɗanda ka iya zama masu rauni kuma sun gano cewa 24 daga cikinsu suna da matsala. A cikin Afrilu 2017, Exelon ya sanar da NRC cewa HPCS allurar bawul 2E22-F004 ya gaza saboda rabuwar tushen bawul da diski. A cikin makonni biyu, ƙungiyar bincike ta musamman (SIT) da aka ba da izini daga NRC ta isa LaSalle don bincikar dalilin gazawar bawul da kimanta tasirin matakan gyara da aka ɗauka. SIT ta yi bitar kimar Exelon na yanayin rashin gazawar bawul ɗin allurar HPCS Unit 2. SIT ta yarda cewa wani sashi a cikin bawul ɗin ya fashe saboda ƙarfin da ya wuce kima. Bangaren da ya karye yana haifar da haɗin kai tsakanin tushen bawul da diski na intervertebral don ƙara zama marar kuskure, har sai diskin intervertebral a ƙarshe ya rabu da tushen bawul. Mai bayarwa ya sake fasalin tsarin ciki na bawul don magance matsalar. Exelon ya sanar da NRC a ranar 2 ga Yuni, 2017 cewa yana shirin gyara wasu 16 da ke da alaƙa da aminci da aminci-muhimmancin Anchor Darling kofa biyu na fayafai waɗanda za su iya zama masu rauni ga wannan gazawar yayin katsewar mai na gaba na rukunin LaSalle guda biyu Tasirin inji. SIT ta sake duba dalilan Exelon na jira don gyara waɗannan bawuloli 16. SIT ta yi imanin cewa dalilin yana da ma'ana, tare da ɗayan ɗayan-bawul ɗin allura na HCPS akan Raka'a 1. Exelon ya ƙididdige adadin zagayowar bawul ɗin allurar HPCS don Raka'a 1 da Raka'a 2. Bawul ɗin Unit 2 shine ainihin kayan aikin da aka shigar a farkon. 1980s, yayin da Unit 1 bawul aka maye gurbinsu a 1987 bayan ta lalace saboda wasu dalilai. Exelon ya bayar da hujjar cewa mafi yawan adadin bugun jini na naúrar 2 ya bayyana gazawarsa kuma akwai dalilin jira har sai katsewar mai ta gaba don warware matsalar bawul don naúrar 1. SIT ya kawo dalilai kamar bambance-bambancen gwajin da ba a sani ba kafin aiki tsakanin raka'a, kaɗan. bambance-bambancen ƙira tare da sakamakon da ba a sani ba, halayen ƙarfin kayan da ba su da tabbas, da bambance-bambancen da ba a taɓa gani ba a cikin shingen bawul zuwa suturar zaren zaren, kuma ya kammala da cewa "wannan shine "Matsalar Lokaci" maimakon "Idan" 1E22-F004 Bawul ɗin zai gaza idan akwai. babu gazawa a nan gaba, SIT bai sayi jinkirin dubawa na Unit 1 bawul ɗin Exelon ya rufe LaSalle Unit a kan Yuni 22, 2017 don maye gurbin sassan ciki na bawul ɗin allura na HPCS 1E22-F004 Ƙimar ƙarfin ƙarfi wanda Exelon ya haɓaka don injinan allurar HPCS 1E22-F004 da 2E22-F004 sun keta 10 CFR Part 50, Shafi B, Standard III, Sarrafa ƙira Ƙimar jujjuyawar motar da ba ta ƙaddamar da bututun bawul zuwa matsa lamba mai yawa. Amma hanyar haɗin gwiwa mai rauni ta zama wani ɓangaren ciki. Ƙimar jujjuyawar motar da Exelon ya yi amfani da shi ya sanya ɓangaren cikin damuwa mai yawa, yana sa shi ya karye kuma diski ya rabu da bawul din. NRC ta ƙaddamar da cin zarafi a matsayin babban mataki na III mai tsanani bisa ga gazawar valve wanda ya hana tsarin HPCS yin ayyukan tsaro (a cikin tsarin matakai hudu, matakin I shine mafi tsanani). Duk da haka, NRC ta yi amfani da hankalinta na tilasta bin doka bisa ga manufofinta na tilasta bin doka kuma ba ta buga cin zarafi ba. NRC ta ƙaddara cewa kuskuren ƙirar bawul ɗin ya yi wayo sosai don Exelon don gani da kyau kuma daidai kafin gazawar bawul ɗin Unit 2. Exelon yayi kyau sosai a wannan taron. Bayanan SIT na NRC sun nuna cewa Exelon yana sane da rahoton Sashe na 21 da Hukumar Kula da Kwarin Tennessee da mai ba da bawul suka yi a cikin 2013. Ba su iya yin amfani da wannan wayar da kan jama'a don ganowa da gyara matsalolin bawul ɗin allura na 2 na HPCS a matsayin nuna rashin aikinsu mara kyau. . Bayan haka, sun aiwatar da matakan da ƙungiyar Masu Tafasa Ruwa suka ba da shawarar ga rahoton kashi biyu na 21. Rashin lahani yana cikin jagorar, ba aikace-aikacen Exelon ba. Laifin da Exelon ya yi game da wannan al'amari shine dalilin tafiyar da Unit 1 ya kasance mai rauni kafin a duba ko bawul ɗin allurarsa na HPCS ya lalace ko kuma ya lalace, har sai an katse mai na gaba. Koyaya, SIT na NRC ya taimaka wa Exelon yanke shawarar hanzarta shirin. Sakamakon haka, an rufe Unit 1 a watan Yuni 2017 don maye gurbin bawul ɗin Unit 1 mai rauni. NRC tayi kyau sosai a wannan taron. Ba wai kawai NRC ta jagoranci Exelon zuwa wuri mafi aminci ga LaSalle Unit 1 ba, amma NRC ta kuma bukaci dukkanin masana'antu su warware wannan batu ba tare da bata lokaci ba. NRC ta ba da sanarwar bayanan 2017-03 ga masu masana'anta a ranar 15 ga Yuni, 2017, game da lahanin ƙira na bawul ɗin ƙofar fayafai biyu na Anchor Darling da iyakokin jagororin sa ido na bawul. NRC ta gudanar da tarurrukan jama'a da dama tare da wakilan masana'antu da masu ba da bawul kan matsalar da mafita. Ɗaya daga cikin sakamakon waɗannan hulɗar ita ce masana'antar ta jera matakai masu yawa, shirin sasantawa tare da ranar ƙarshe da aka cimma kafin 31 ga Disamba, 2017, da kuma bincike kan amfani da Anchor Darling biyu faifan faifan diski a cikin ikon nukiliyar Amurka. tsire-tsire. Bincike ya nuna cewa ana amfani da kusan 700 Anchor Darling biyu disc gate valves (AD DDGV) a cikin tashoshin makamashin nukiliya a Amurka, amma bawuloli 9 kawai suna da halayen haɗari mai girma / matsakaici, bawuloli masu yawa. (Yawancin bawul ɗin bugun jini guda ɗaya ne, saboda aikin lafiyar su shine rufewa lokacin buɗewa, ko buɗewa idan an rufe su. Ana iya kiran bawul ɗin buɗaɗɗen buɗaɗɗe da buɗewa, kuma ana iya buɗewa da rufe sau da yawa don cimma aikin kiyaye lafiyar su.) masana'antu har yanzu suna da lokaci don dawo da gazawarta daga nasara, amma NRC tana da alama a shirye take don ganin sakamako mai dacewa da inganci daga wannan lamarin. Aika SMS "SCIENCE" zuwa 662266 ko yin rijista akan layi. Yi rijista ko aika SMS "SCIENCE" zuwa 662266. Ana iya cajin SMS da kuɗin bayanai. Rubutun ya daina ficewa. Babu buƙatar saya. Sharuɗɗa da sharuɗɗa. © Union of Concerned Scientists Mu kungiya ce mai zaman kanta ta 501(c)(3). 2 Brattle Square, Cambridge MA 02138, Amurka (617) 547-5552