CEC-JOINT RESEARCH CENTRE INSTITUTE OF SYSTEMS ENGINEERING AND INFORMATICS-ISPRλ SITE OSS OF VACUUM ACCIDENT ANAYSIS Y.Caouris, P.Rocco ITER S+E Workshop 30.7-3.8.1990, Garching (FRG)
1 MODEING ΤΗΕ COMPUTER CODE "SIFNOS". ASSUMPTIONS ΟΝ ΤΗΕ BREACHES AND RADIOACTIVE MATERIAS MOBIIZATION. -Α TRANSIENT THERMODYNAΚIC ΗΕΑΤ TRANSFER ΚODE HAS ΒΕΕΝ DEVEOPED, WIm 5 NODES, Ι _ Ε _ : 1.-GAS; 2, 3-CONDUCTION-COOED GRAPHITE; 4-RADIATION - COOED GRAPHITE; 5-STEE _ - ΤΗΕ GAS INFUX AND EFFUX ARE CONSIDERED AS ISENTROPIC _ WHEN THERE ARE ΝΟ BREACHES ΑΤ DIFFERENT HEIGHTS, STACΚ EFFECTS ARE CONSIDERED AND FRICTION IS ΤAΙCEN ΙΝΤΟ ACCOUNT _ - ΤΗΕ DIFFERENT INITIA TEMPERATURES OF me CONDUCTION - AND RADIATION - COOED GRAPHITE ARE ΤAΙCEN ΙΝΤΟ ACCOUNT _ - ΤΗΕ ΗΕΑΤ OF REACTION (C-t-O::.z) IS REEASED ΤΟ GAS AND GRAPHITE ΙΝ Α 5 Ο - 5 0% PR.OPORTION_ - ΤΗΕ GRAPHITE COMBUSTION RATES ΑΤ me DIFFERENT TEMPERATURE REGIMES ARE ΤAΙCEN FROK INE./1../ AND CEA./2./ RESUTS _ me COMBUSTION PR.ODUCTS' RATIO CO./CO::.z IS PR.OPORTIONA ΤΟ ΑΝ INVER.SE EXPONENTIA OF me TEΚPERATURE./2./ _ - ΤΗΕ OXYGEN ΑΚΟυΝΤ WImIN me TORUS IS CONTROED CONTINOUSY ΤΟ ASSESS WHEmER me ASSUMED COMBUSTION RATE IS MAINTAINED_ - ΤΗΕ AIR INRUSH HAPPENS mrough FAIED AUNCHERS ( 1. ΤΟ 3 Ο ) OF ΤΗΕ EECTRON CYCOTRON SYSTEΚ WICH ENTER me TORUS MID - PANE _ me GASES WImIN me TORUS (UNCOMBUSTED AIR-t- COMBUSTION GASES) ARE EXPEED FROM me SAME BREACH_ ΙΝ SOME EXAΚINED CASES GASES ARE EXPEED FROK Α BREACH ΟΝ me TORUS ΤΟΡ, WICH IS PR.ODUCED ΑΤ ΤΗΕ ΜΟΜΕΝΤ WHEN me TORUS INNER PRESSURE EQUAS me ATΚOSPHERIC PR.ESSURE _ - ΤΗΕ ΚOBIIZED RADIOACTIVE MATERIAS CONSIST OF TRITIΌM AND ERODED - SP1JTrERED PARTICUI.ATES FROK METAIC SURFACES EXPOSED ΤΟ PASMA _ GRAPHITE ACTIVATION IS NEGIGIBE _ mese MATERIAS ARE UNIFORΚY DISPERSED ΙΝ me PASMA CHAMBER_ - ΤΗΕ EXPEED FRACTION OF ΚOBIIZED MATERIAS IS EQUA ΤΟ me EXPEED FRACTION OF COMBUSTION GAS _ R.EFERENCES 1. _ INE INFORΚA R.EPORT EGG-FSP 8255, SEPT _ 1988 _ 2 _ CHAPTER 3, OSS OF νacuόm ACCIDENT, DRAFT OF Α CEA CONTRIBUrION ΤΟ ΤΜΚ S ΕΑ - 3, 1989
2 INPUT DATA AND ASSUMPTIONS FROK /3/, ΙΤ IS: - PIASΚA CHAΚBEB. VOUΚE : 1473Κ:Ζ - TOROIDA CROSS - SECTIONA AREA : 41 _ 4Κ:Ζ - FIRST WA SURFACE: 734Κ:Ζ - DIVERTOR SURFACE : 209Κ:Ζ - GRAPHITE THIClCNESS: 20ΚΚ - STEE THIClCNESS: 3ΚΚ ΤΟ Η:ΖΟ, 20ΚΚ TOTA - SURFACE TEΚPERAroR.E OF GRAPHITE: 1000 C ΟΝ 90% OF ΤΗΕ SURFACE 1500-155OOC ΟΝ 9 % 1740-1860o C ΟΝ 1% - S URFACE TEΚPERAroR.E OF STEE: 22S-2S0o C _ - ΙΝ ΤΗΕ PRESENTED ANAYSIS ΤΗΕ BREACH ΑΤ ΤΗΕ TORUS KIDPANE CONSISTS OF 3 Ο FAIED AUNCHERS (SO _ 23 SK:Z) ; ΤΗΕ ADDITIONA BREACH ΟΝ ΤΟΡ CONSISTS OF Α 20CΚ DIAΚETER HOE; STACΚ ' S HEIGHT: SK_ - FRICTION ΙΝ ΤΗΕ BREACHES DUC'rS IS ΤΑΚΕΝ ΙΝΤΟ ACCOUNT FOR EVAUATING STACΚ EFFECTS _ - ENGTH OF ΤΗΕ DUCTS : SK AND Ο _ SK FOR ΤΗΕ ΚΙ» - PANE AND ΤΟΡ BREA.CH RESPECTIVEY _ REFERENCE 3 _ Η _ W _ BARTES, GEOΚETRY AND ΚATERIAS DATA OF ITER. FOR SAFETY STUDIES, ΝΟΤΕ OF 2 Ο APRI, 199Ο _
3 R-ESUTS -Ι- SINGE BREACH ΑΤ ΤΗΕ TORUS MID-PANE. - ΝΟ SIGNIFlCAN'r OVER PRESSURE DEVEOPS,. SEE FIG 1_ P...x-102KPA(ABS _ ) _ -.AFl'ER ΑΝ ΙΝΙΤΙΑΙ.. PHASE OF ABOτrr 200S,. DURING VHICH COMBUSTION AND GAS EXPUSION ΤΑΚΕ PIACE,. 'DIE REDUCfION OF ΤΗΕ TOR.US GAS PRESSURE,. DUE ΤΟ ΤΗΕ GAS EXPUSION AND ΤΗΕ ΗΕΑΤ TRANSFER.. PRODUCES Α PUSED PROCESS WITH ATERNATE PHASES OF AIR INGRESS AND (WEAΚ ) GAS EXPUSION _ Ι Ν THIS SECOND PHASE ΤΗΕ GRAPHlTE COΚBUSTION IS NEGIGIBE FOR ITS TEMPERATURE DECREASE _ - ΤΗΕ GAS AVERAGE TEMPERATURE ΙΝ ΤΗΕ TORUS REACHES Α ΜΑΧΙΜΟΜ OF 11S ΟΚ ΙΝ ABOτrr 200S,. TREN ΙΤ DECREASES,. SEE FIG 2 _ THIS VAUE IS OVER. ΤΗΑΝ ΤΗΑΤ OF PREVIOUS EVAUATIONS,/4,/ FOR ΤΗΕ ASSUMED SO - SO% APPORTIONMENT OF ΤΗΕ COMBUSTION ENERGY ΤΟ GAS AND GRAPHlTE,. WHEREAS ΙΝ,/4,/IΤ WAS 100% ΤΟ GAS_ ΤΗΕ TEMPERATURE DECREASES ΙΝ ΤΗΕ STEE FIRST VA AND ΙΝ ΤΗΕ CONDUCTION AND RADIATION - COOED GRAPHITE ARE ASO SHOWN _ - FIG _ 3 SHOWS ΤΗΕ MASS OF AIR ENTERING ΤΗΕ TORUS,. ΤΗΕ ΑΜΟυΝΤ OF GRAPHITE BURNED,. ΤΗΕ CO AND CO:2 EXPEu.ED,. ΤΗΕ ΤΟΤΑΙ.. MASS OF GAS EXPEED _ AFTER 200S,. ΙΤ IS : M AyR-=6 3 SKG ; Μα _ Β _ -76KG ; MC::C>:2-SKG; ΜΖχΡ _ -229KG_ - ΤΗΕ EXPEu.ED GAS FRACTION IS Ο _ 32 _ - ΤΗΕ ANAYSIS CARR.IED oτrr PREVIOUSY,/4,/,. SHOWED ΤΗΑΤ ΤΗΕ OVA DEVEOPMENT ΙΝ ΤΗΕ CASE OF Α SMAIJ.. BREACH SIZE (ΟΝΕ THIRD OF ΤΗΕ ACTUA BREACH) IS MIDER ΤΗΑΝ ΤΗΑΤ EXAMlNED HERE,. WIm REDUCED BURNING AND EXPUSION ΡΗΕΝΟΜΕΝΑ _ R..EFERENCE 4 _ Υ _ CAOURIS,. Ρ _ R-OCCO,. JR-C Τ _ Ν _ ΚΟ _ Ι _ 90 _ 31 ISPRA,. APRI 1990 _
4 R-ESUTS -ΙΙ- BREACHES ΑΤ ΤΗΕ TORUS MID-PANE AND ΤΟΡ. STACK EFFECTS. - ΤΗΕ ADDITIONA BREACH ΑΤ ΤΗΕ TσRUS ΤΟΡ AND ΤΗΕ CσNSEQUENT DRIF'lΊNG FσRCE FσR ΤΗΕ STACΚ EFFECTS PRσDUCES ENG'I'HENED AIR IRRUSH FR.σM ΤΗΕ MID - ΡΙΑΝΕ BREACH AND GAS EXPUSlσN FR.OM ΤΗΕ ΤΟΡ, SEE FIG 4 _ ΙΤ CAN ΒΕ ΝOTED HσWEVER. ΤΗΑΤ AFTER AB01rr 1000S ΤΗΕ GRAPHlTE BURNING IS NEGIGIBE _ THIS IS DUE ΤΟ' ΤΗΕ PROGRESSIVE COOING σf ΤΗΕ TlES, SEE FIGS 2 AND 5 _ - ΤΗΕ COOING σf ΤΗΕ CσNDUCTlσN - COOED TlES PRσDUCES ΑΝ σνε - ORDER. - σf - MAGNlTUDE REDUCTlσN σf ΤΗΕ INITIA CσMBUSTlσN RATE 40S AFTER ΤΗΕ REACTOR SHUT - DOνν BREACH _ WICH IS ΤΑΚΕΝ ΤΟ CσlNCIDE '11m ΤΗΕ σpening σf ΤΗΕ MID - ΡΙΑΝΕ ΤΗΕ SAME σνε - σrder. - σf MAGNlTUDE REDUCTlσN ΙΝ ΤΗΕ RADIATlσN - COOED TlES IS ATTAlNED AFTER 1300S_ -AFTER. 1000S, ΤΗΕ REACTED GRAPHlTE ΑΜΟυΝΤ IS AB01rr 190KG, Ι _ Ε _ 2 _ 5 TlMES ΤΗΑΤ BURNED ΙΝ ΤΗΕ SINGE - BREACH ACCIDENT, vlmouτ ΑΝΥ FUR.mER INCREASE _ ΤΗΕ EXPUSlσN σf CσMBUSTlσN GAS CσNTlNUES AND, AFTER 3 Ο OOS ΤΗΕ EXPEIJ..ED AMOUNTS σf CO AND CO::2 ARE 2 Β 3KG AND 230KG RESPECTlVEY, CσNTAINING 1 Β 3KG σf GRAPHlTE, Ι _ Ε _ 96% σf ΤΗΕ TσTA BURNED _ - ΤΗΕ ΜΑΙΝ DIFFER.ENCES σf mls ACCIDENT FR.σM ΤΗΕ SINGE BREACH σνε ARE : *ΤΗΕ REACTED GRAPHlTE ΑΜΟΌΝΤ, AmσUGH INCREASED, REMAINS Α SMA FRACTlσN σf ΤΗΕ TOTA INVENTσRY _ *ΤΗΕ AIR ENTER.ING ΤΗΕ TσRUS AND ΤΗΕ GAS EXPEED AMOUNTS ARE MUCH GR.EATER. ΤΗΑΝ ΙΝ ΤΗΕ SINGE BREACH CASE _ ΤΗΕΥ ARE ONG ASTING ΡΗΕΝσΜΕΝΑ_ *ΤΗΕ SVEEPING EFFECT σf GASES CRσSSING ΤΗΕ TORUS σν ΤΗΕ MOBIIZED RADlσACTlVE MATER.IAS IS VERY EFFICIENT _ ΤΗΕ EXPJU,.ED FRACTIσN σf THESE MATER.IAS IS ΤΑΚΕΝ EQUA ΤΟ ΤΗΕ 'ΟΝΙΤΥ, WER.EAS ΙΝ ΤΗΕ SINGE BREACH CASE IS Ο _ 32 _
5 PANT'S CONTAMINATION ΑΝΩ RADIOACTIVE IMPACT - ΤΗΕ MOBIIZED RADIOAGΊIVE MATER.IAS ARE TRITIUM AND METAIC PARTICUATES. ΤΗΕ GRAPHITE ACTIVATION PRODUCTS (Cl4-, Ρ32, S 3 5) CAN ΒΕ NEGECTED./ 5./ - DATA ΟΝ TRITIUM INVENTORIES ARE ΤΑΚΕΝ FROM./6./ ASSUMING PARTIA REEASES OF TRITIUM FROM ΤΗΕ CRYOPUMPS, ΤΗΕ TIES AND ΤΗΕ DIVERTOR ARMOUR AND Α TOTA REEASE OF ΤΗΑΤ ΙΝ ΤΗΕ GRAPHITE DUST, ΤΗΕ MOBIIZED TRITIUM (ΉΤΟ) IS ΤΑΚΕΝ ΤΟ ΒΕ 200G. - ΤΗΕ PARTICUATES (AISI - 316 ) DERIVE FROM EROSION - SPUTTERING OF BARE METAIC SURFACES _ SCAING FR.OM./7./ ΤΗΕΥ ARE ΤΑΚΕΝ ΤΟ ΒΕ 1 Ο OG, WITH Α SPECIFIC RADIOACTIVITY OF Ο _ 31TBQ./G (FR.OM./8./, FOR Α FUENCE OF 1ΚW YR./M:2) - ΤΗΕ EXPUSION OF THESE MATER.IAS ΙΝ ΤΗΕ REACTOR ROOMS PRODUCE SEVERE CONTAMINATION PROBEΚS _ ASSUMING Α REEASE FRACTION OF Ο 32 (SINGE BREACH CASE) AND Α CONTAMINATED ROOM OF 3 5 Ο Ο Μ3, WHICH IS ΤΗΕ VOUME OF ΤΗΕ CE CONTAINING ΤΗΕ ECS FOCUSSING DEVICES, ΤΗΕ TRITIUM EVES ARE ABOUf 8X10 DAC (FROM./9./, ΤΗΕ DERIVED AIR CONCENTRATION IMIT OF ΉΤΟ FOR WORΚERS IS 8Χ10.5 BQ./M3). - NEGECTING REDEPOSITION INSIDE ΤΗΕ PANT AND CONTAINMENTS, ΤΗΕ RADIOACTIVE MATERIAS REEASED ΤΟ ΤΗΕ ENVIRONMENT ΙΝ ΤΗΕ SINGE BREACH CASE ΗΑνΕ ΤΗΕ FOUDWING EFFECTS (EARY EDE ΑΤ 1ΚΜ, WEATHER CONDITIONS F2, 20Μ REEASE HEIGΉT ) TRITIUM : _ _ _ 24-MSV./10./ AISI - 316 PARTICUIATES: _ _ Ο _ SMSV./8./ - ΤΗΕ RADIOOGICA EFFECTS ΙΝ ΤΗΕ DOUBE BREACH CASE ARE ΑΒΟΌΤ 3 TIMES GREATER. (REEASE FRACTION1) _ R..EFERENCES. 5 _ c. ΡΟΝΤΙ, ACTIVATION CACUATΙONS FOR ΝΕΤ SHIEDING BANΚET, JRC Τ _ Ν ΝΟ Ι. 8 8 _ 7 3.. ISPRA.. 1988 6 ITER- I. SA _ 4- Ο 27.. ITER INTERNA ΝΟΤΕ.. APRI 1990. 7 _ INTOR, PHASE ΝΟ Α.. ΡΜΤ ΠΙ.. ΙΑΕΑ VIENNA, 1988 8 _ ITER S-f-E TASK 4-. 4, US RESUTS.. DECEMBER 29.. 1989. 9 RADIOOGICA PROTEGΊION - 21, OFFICIA JOURNA OF ΤΗΕ EUROPEAN COMMUNITIES.. 24-6 OF 1 7 9 198Ο.. EUR 7330. 10 ITER S-f-E HOMEWORΚ, JUNE - OCTOBER S ESSION.. ' OCTOBER 9, 1989_
..... 120000 30 aunchers Breached, \ινlτηυτ Stack effect 0100000 " 0_ '--'" 80000 G :J Ο 60000" f-- 4-' Ο Q) :J 40000 Atmospheric Pressure: 101325 Ρα Fi g. 1 Q) -1 (l 20000 :: ΟΊ 0--1 1I ΓΓΤ"ΓΓΙ ' Ι Ι,--,-Γ-ΓΓΓΓΤ-Γ-ΓΓ-Γ-,-Τ Ι Ι 1-IιΓΓΓT-ΓT-' Ο 50 100 150 200 Time (s)
-(.. 2000 30 aunchers Breached, ννlτηυτ Stack effect Υ- -- -- -- -- - - - - - - - U1 - - - - 1500 - :J Torus Gas Temρerature +J Ο ConductionCooled Graphite Temp. Q) Radiation Cooled Graphite Temp. -- Q. Steel Temρerature Ε \ -- - - 1000 U1 '" --.- ω - "" " -- --...J / " Fig. 2... '-... 500 -- -- - --._'-'_._.---:. U1 --------------------------- ----------------- 1.9 Ο --ΙιΤ ι ΤΤΤ,ΓΙ ΓΓΓΓΓΓΓΓΓΓΓΠΤΤΠ-ΓΓΓΓΓΓΙ Ι Ι Ι Ι Ι ι Ι Ι ι Ι Ι -ΓΓΓΠ-, Ο 50 100 150 200 250 Time (s)
fi':'.. t 800 "--" 30 aunchers Breached, WITHOUT Stack effect Ό ω c :J. m 600 Q) -4-1 Ι -.C 3 Ι Mass of ΑίΓ Entering the Torus... - -- Mass of Gas Expellea from the Torus -.- Mass of Graphite Burned σ () 400 Ι. - - - Mass of CO 2 Expelled.------ Mass of CO Expelled Ι ω () 200 -Ί Ι 4- Ο Ι Fig. 3 - - -- - /'" /'" /'" --_.. --. /'.-.-. -' _.- - - _.-.-'-' 2 Ο ιc; - ι <ί : Γ'ιΤ-ϊ - ϊ ϊ - Γι =,- ϊ-=-r-r=ϊ---=r=-rn=-τ.,=ι=r ι ι Ι Ι Ι Ι Ι Ι ι Ι Ι ι i Ο 50 100 150 200 Time (s) --. ---.--.-. - --------------------- ---
.".i., Ι 6000 30 aunchers Breached, ννlτη Stak effect '--./ Ό Q) C Mass of Entering Air through aunchers /' - - Moss of Gas Eχpelled :::J / rn. -. - Mass of Graphite Burned Q) 4000. - - - Mass of CO 2 Eχpelled /.------ Mass of CO Eχρelled -+--..J /...c / Ο. / G Fig. 4 Q) 2000 / / G / 4 Ο /,/ ;;:-:::= Ο. ι ι F ι / / -= - -- --=-=-= - - =-=-:;...- :...: ::.:: =...;:::..;..:: ::::.: :- - -:-::...- -: - - -:::...- -: - =-- :,/ Ο 1000 2000 3000 Time (s) \.Ο
J (:._ 2000 30 aunchers Breached, ννlτη Stack effect,..----,. \ Υ: \ "---' \ Torus Gas Temperature 1500 \ -.- Conduction Cooled Graphite Temp. \. - - - Radiation Cooled Graphite Temp. ::J \ ----'--- Steel Temperature -+-Ι \ Ο '\ '\ Q) " Ω- " " Ε 1000 """ Q)... Ι-. \... _ \ \ \ F 5 Ι- l. \ ι 9. \ \ - ---.. 500-1\\,. " cn -----------------==---==-- () ', "- OI Ο 1000 2000 3000 Time (s)