Development of Free-standing Rack Seismic Evaluation Method

Transcription

1 103 Dvopmnt of Fr-standing Rack Sismic Evauation Mthod AKIHISA IWASAKI *1 YOSHITSUGU NEKOMOTO *2 HIDEYUKI MORITA *3 JUNICHI KISHIMOTO *4 KATSUHIKO TANIGUCHI *5 YU TAKAKI *5 Th spnt fu takn out of a ractor in a nucar powr pant is tmporariy stord in a spnt fu rack unti it is carrid out to an intrmdiat storag faciity or a rprocssing faciity. Th spnt fu rack rquirs high arthquak rsistanc. Th fr-standing rack has no supporting mmbrs around it and disprss sismic nrgy with friction by siding, and th watr around th rack rducs th rspons. Thrfor, it can b xpctd to provid high arthquak rsistanc. In considration of thr-dimnsiona bhavior, coisions and fuid-structur intraction accompanid by siding and rocking during a arg xcitation, th sismic vauation mthod for th fr-standing rack was stabishd, and its vaidity was confirmd through a comparison with th rsuts of th fu-sca xcitation tst conductd at E-Dfns*. In this rport, th sismic vauation mthod for th fr-standing rack is dscribd. * On of th word's argst shak tabs at th thr-dimnsiona fu-sca arthquak tsting faciity at th Hyogo Earthquak Enginring Rsarch Cntr of th Nationa Rsarch Institut for Earth Scinc and Disastr Rsiinc. 1. Introduction With th occurrnc of major arthquaks in rcnt yars, it is important that th major quipmnt of nucar powr pants has high arthquak rsistanc, and spnt fu racks which can withstand major arthquaks ar in dmand. In ordr to mt this dmand, th dvopmnt of fr standing-typ spnt fu racks (fr-standing rack) has bn conductd. Th fr-standing rack (Figur 1) has no supporting mmbrs around it and is pacd dircty on th spnt fu pit foor. Thrfor, it is not ncssary to considr th proof strss of supporting mmbrs, and in th vnt of an arthquak, th arthquak input to th fr-standing rack itsf is rducd by th siding of th fr-standing rack, in contrast to a wa supporting-typ or foor supporting-typ rack. In addition, th fr-standing rack disprss sismic nrgy with friction by siding, and th watr around th rack rducs th rspons. As such, this dsign mthod can b xpctd to contribut to th dvopmnt of highr arthquak rsistanc. Th rack cs of th fr-standing rack ar oadd with spnt fu. In th vnt of an arthquak, th fu vibrats in th rack c, th fu and th rack c coid, and th fr-standing rack not ony sids but aso rocks (th phnomnon that th rack gs ift up). Thrfor, for th dsign of th fr-standing rack, it is ncssary to stabish an anaysis mthod by which thr-dimnsiona noninar vnts such as siding, rocking and coisions can b vauatd. Th purposs of this rsarch ar to stabish an sismic vauation mthod for th fr-standing rack, to chck th vaidity of th sismic vauation mthod through an xcitation tst for a fu-sca fr-standing rack, and to raiz th prospct for practica us. *1 Vibration Rsarch Dpartmnt, Rsarch & Innovation Cntr *2 Chif Staff Managr, Vibration Rsarch Dpartmnt, Rsarch & Innovation Cntr *3 Chif Staff Managr, Vibration Rsarch Dpartmnt, Rsarch & Innovation Cntr *4 Managr, Nucar Pant Componnt Dsigning Dpartmnt, Nucar Enrgy Systms Division, Enrgy & Environmnt *5 Nucar Pant Componnt Dsigning Dpartmnt, Nucar Enrgy Systms Division, Enrgy & Environmnt

2 104 Figur 1 Fr-standing rack Th fr-standing rack is surroundd by th outr priphra boards and th gs hav a rotation mchanism to prvnt strss from bing concntratd du to rocking. 2. Sismic anaysis mthod A sismic anaysis mthod intndd for thr-dimnsiona noninar bhaviors incuding siding and coisions was stabishd, and a vibration tst using a shak tab was conductd for th fu-sca fr-standing rack in watr for th first tim anywhr in th word. As a rsut, it was confirmd that th siding and rocking bhaviors, coision oad, tc., in th fu-sca tst can b simuatd by th anaysis, which aows th vauation of th structura intgrity of th fr-standing rack against major arthquaks. 2.1 Anaysis mod Th vibration rsponss of th fr-standing rack ar thr-dimnsiona noninar bhaviors such as siding, rotation and coisions as shown in Figur 2. An outin of th anaysis mod is shown in Figur 2. Th fr-standing rack and fu ar modd by on bam, and th fuid structur intraction btwn th fr-standing rack and th pit and btwn th fu and th rack c is takn into account. Aso considrd ar coisions (spring, damping, gap) and friction btwn th fr-standing rack gs and th pit foor and btwn th fu and th bas pat, as w as coisions (spring, damping, ratting) btwn th fu and th rack c. For th sismic anaysis of th fr-standing rack, Adams (MSC Softwar) was usd as th Mutibody Dynamics softwar. Figur 2 Outin of anaysis mod of fr-standing rack Th fr-standing rack and fu assmby ar modd by on uniform bam, and th coision part was simuatd by a spring and dampr.

3 2.2 Siding and rocking conditions Th siding and rocking bhaviors of th fr-standing rack ar xpaind using a two-dimnsiona physica mod for horizonta and vrtica motions. For simpifying th xpanation hr, gomtrica noninarity, dformation of bas pat and ratting du to fu ar ignord, and infunc of vrtica xcitation and th cntrifuga forc causd by vibration is not considrd, athough thy ar usd in th actua anaysis mthod. In addition, th ffcts of fuid ar not takn into account. Whn th xcitation v of sismic motion is ow, siding or rocking dos not occur. Whn th xcitation v bcoms highr, ithr siding or rocking bhavior for which conditions ar satisfid arir occurs. 105 Figur 3 Siding and rocking bhaviors Th arthquak rsponss of th fr-standing rack consist of thr bhaviors: siding, rocking, and th concurrnt occurrnc of siding and rocking. As shown in Figur 3, whn th accration of pit foor & x& and th rativ vocity (siding vocity) of th fr-standing rack to pit foor u& ar ngativ, th condition of siding can b xprssd by th foowing quation: m& x > mgμ (1) s whr m is th mass of th fr-standing rack, g is th gravitationa accration, and μ s is th cofficint of static friction. In addition, th condition of rocking is xprssd by th foowing quation: m& x h > mg (2) whr h is th hight of cntr of gravity of th fr-standing rack, and is th horizonta distanc from th g which is th fucrum of rocking to th cntr of gravity. Furthrmor, whn th xcitation v bcoms high, siding and rocking simutanousy occur. Th condition whr rocking starts during siding is xprssd by th foowing quation: + u& ) h > mg (3) Th condition whr siding starts during rocking is xprssd by th foowing quation: h && φ ) > μsm( g + & φ ) (4) whr & φ is th rotationa anguar accration around th g which is th fucrum of rocking. Th quations of motion in th horizonta dirction (siding) and rotationa dirction (rocking) whn siding and rocking simutanousy occur ar as foows:

4 + u&& ) = μ m( g + && φ ) + mh & φ (5) I & φ = mg + m( && x + u& ) h (6) whr μ is th cofficint of kintic friction, and I is th momnt of rotatory inrtia. Whn th xcitation is arg, th mixing bhavior of siding and rocking occurs. In that cas, th bhavior of th fr-standing rack wi b cacuatd basd on quations (5) and (6). In actua fact, it nds to b considrd in thr dimnsions, and it is aso affctd by gomtrica noninarity and astic rspons, rsuting in a compicatd cacuation. 2.3 Fu-sca xcitation tst Th thr-dimnsiona fu-sca arthquak tsting faciity (E-Dfns) at th Hyogo Earthquak Enginring Rsarch Cntr of th Nationa Rsarch Institut for Earth Scinc and Disastr Rsiinc was usd to conduct th sismic tst for th fu-sca fr-standing rack pacd in a arg poo fid with watr. An outin of th sismic tst is shown in Figur 4. Th fr-standing rack tst body is composd of 7 10 rack cs, has th dimnsions of 4.5 m in hight, 2 m in width and 3 m in ngth, and wighs about 70 tons with th mock-up of fu bing oadd. Th gs ar structurd to b rotatab to prvnt strss from bing concntratd whn rocking occurs. Th xcitation sismic wav dividd into short priod, mdium priod, and ong priod as shown in Figur 5 was usd. Athough th fr-standing rack has no frquncy rspons to sismic motion, th rsuts showd that th rspons was sma in th short-priod wav and mdium-priod wav, whi th rspons was car in th ong-priod wav in which th siding tim (during which th accration is arg) is ong and th xcitation dispacmnt is arg, as shown in Figur Figur 4 Outin of sismic tst Using E-Dfns, th sismic tst for th fu-sca fr-standing rack was conductd. Figur 5 Excitation sismic wav A sismic wav dividd by short priod, mdium priod and ong priod was usd in th sismic tst. Figur 6 Tst rsuts (xcitation in on horizonta dirction) Th fr-standing rack siding dispacmnt and g upift dispacmnt in th sismic tst ar shown.

5 2.4 Comparison btwn tst and anaysis rsuts Th tst and anaysis rsuts for th ong-priod sismic wav xcitation which xhibitd a car rspons ar shown in Figur 7. Th tst rsuts and th anaysis rsuts for siding dispacmnt, g upift dispacmnt and oading agrd, and th vaidity of th anaysis was confirmd. 107 Figur 7 Comparison btwn tst and anaysis (simutanous xcitation in thr dirctions) Th siding dispacmnt, g upift dispacmnt and g oading in th sismic wav xcitation tst and th anaysis ar shown. 3. Concusion This rport summarizs th rsuts of th joint rsarch conductd by fiv Japans ctric companis oprating prssurizd watr ractor nucar powr pants, and hr w xprss our gratitud for th vauab advic rcivd from th partis concrnd. Th concusion of this artic is as foows: (1) It was confirmd that th sismic anaysis of th fr-standing rack using th mchanism anaysis can vauat siding dispacmnt, g upift dispacmnt and oading accompanid with th siding and rocking of th fr-standing rack. (2) Through a comparison of th siding dispacmnt, g upift dispacmnt and oad obtaind in th fu-sca xcitation tst, th vaidity of th anaysis vauation mthod was vrifid. (3) Sinc it was confirmd that th fr-standing rack can b vauatd by sismic anaysis, it was aso confirmd that an actua fr-standing rack can b achivd, and a crtain prospct toward th practica us of th fr-standing rack was obtaind. Rfrncs 1. Iwasaki,A., Nkomoto,Y., Morita,H., Taniguchi,K., Okuno,D.,Matsuoka,T. and Chigusa,N., Practica rsarch of fr standing rack (Sismic xprimnt study on fu sca fr standing rack), Transactions of th Japan Socity of Mchanica Enginrs (in Japans), Vo.81, No.831 (2015), DOI : /transjsm Iwasaki,A., Nkomoto,Y., Morita,H., Taniguchi,K., Okuno,D.,Matsuoka,T. and Chigusa,N., Practica rsarch of fr standing rack (Dvopmnt of sismic vauation mthod), Transactions of th Japan Socity of Mchanica Enginrs (in Japans), Vo.81, No.831 (2015), DOI : /transjsm Dvopmnt of Fr Standing Spnt Fu Rack, Mitsubishi Havy Industris Tchnica Rviw Vo. 43 No. 4 (2006)