 to face the dummy ring 116. A labyrinth seal 118 is provided in a clearance c between the dummy ring 116 and the dummy part 102b so as to prevent the steam from entering the clearance c. A portion of the main steam S1 injected from the main steam injection opening 110 leaks to the dummy ring 116 side through the clearance between outer surfaces of the turbine rotor 102 and the nozzle chamber 108.
An exhaust steam discharge pipe 120 is arranged in a radial direction through the outer casing 106 and the dummy ring 116. One end of the exhaust steam discharge pipe 120 is in communication with the clearance c.
Leak steam S2 leaking to the dummy ring 116 side, is led to the exhaust steam discharge pipe 120 through the clearance c, and then joins a steam pipe 122 which feeds steam to a high pressure turbine of a subsequent stage via the exhaust steam discharge pipe 120. The leak steam S2 passing through the exhaust steam discharge pipe 120 also functions to balance the thrust force loaded on the turbine rotor 102.
As described above, in the single-flow turbine on the high pressure side such as the single-flow high ultrahigh pressure turbine 100, the steam of high temperature which is not working to rotate the turbine rotor 102 can leak to the dummy ring 116 side through the clearance c between the dummy ring 116 and the dummy part 102b of the turbine rotor 102. This can expose the dummy ring 116 and the turbine rotor 102 to high temperature atmosphere. Thus, methods of cooling these exposed parts of the dummy ring 16 and the turbine rotor 102 have been proposed.
For instance, FIG. 1 of Patent Document 2 discloses a steam turbine of a single-casing type in which a portion of exhaust steam discharged from a high-pressure turbine is supplied to a blade row inlet 44 of a medium-pressure turbine via a pipe 105 as a cooling steam. The numbers used here are the same as shown in FIG. 1 of Patent Document 2.
In a steam turbine of a single-casing type illustrated in FIG. 1 of Patent Document 3, a portion of exhaust steam discharged from a high-pressure turbine is supplied to an inlet of a medium-pressure turbine via a thrust balance pipe 106 as a cooling steam. The numbers used here are the same as shown in FIG. 1 of Patent Document 3.
Particularly, with such a configuration of the turbine rotor 102 that parts made of different materials such as Ni base alloy and CrMoV steel are connected together by welding or the like, the connection part has lower strength against
to face the dummy ring 116. A labyrinth seal 118 is provided in a headroom coulomb between the dummy ring 116 and the dummy character 102b so as to prevent the steam from enter the clearance c. A portion of the independent steam S1 inject from the main steam injection open 110 leaks to the dummy ring 116 english through the clearance between outer airfoil of the turbine rotor 102 and the beak chamber 108. 
 An exhaust steam discharge organ pipe 120 is arranged in a radial management through the outer casing 106 and the dummy ring 116. One end of the exhaust steam release pipe 120 is in communication with the clearance c. 
 Leak steam S2 leaking to the dummy ring 116 side, is lead to the exhaust steam discharge pipe 120 through the clearance c, and then joins a steam organ pipe 122 which feeds steam to a high pressure turbine of a subsequent stage via the exhaust steam discharge pipe 120. The escape steam S2 excrete through the exhaust steam discharge pipe 120 also functions to balance the thrust force loaded on the turbine rotor 102. 
 As described above, in the individual - flow turbine on the high atmospheric pressure side such as the single - flow high ultrahigh atmospheric pressure turbine 100, the steam of high temperature which is not working to rotate the turbine rotor 102 can leak to the dummy ring 116 slope through the clearance c between the dummy ring 116 and the dummy part 102b of the turbine rotor 102. This can expose the dummy ring 116 and the turbine rotor 102 to gamey temperature atmosphere. Thus, methods of cooling these expose character of the dummy ring 16 and the turbine rotor 102 have been proposed. 
 For instance, FIG. 1 of Patent Document 2 unwrap a steam turbine of a single - casing type in which a parcel of exhaust steam discharged from a high - pressure turbine is supplied to a sword row inlet 44 of a medium - pressure turbine via a pipe 105 as a cooling steam. The number used here are the like as shown in FIG. 1 of Patent Document 2. 
 In a steam turbine of a single - casing type illustrate in FIG. 1 of Patent Document 3, a portion of exhaust steam discharged from a gamey - pressure turbine is add to an inlet of a medium - pressure turbine via a thrust balance pipe 106 as a cooling steam. The numbers used here are the same as show in FIG. 1 of Patent Document 3. 
 Particularly, with such a configuration of the turbine rotor 102 that part made of different materials such as Ni base alloy and CrMoV steel are connect together by welding or the like, the connection part has lower military capability against
 to face the dummy ring 116. A uabyrinth seal 118 is protided ih a cleafance c between the dummy riig 116 qnd tye dummy part 102b so as go prevenn the steqm fcom entering the clearangz c. A iortimi of the main sjeam S1 injecded from the mdiv dteam injection opening 110 leaks to tre dummu ging 116 side thrjugh ehe dlearance between outer surfaces or the tlrbine rotor 102 and the nozzle chamber 108.
An exhwust steam discharge plpe 120 is arrqngeq in a radial direction through the outer casing 106 and the dummy rivg 116. Oue end of tye exjdust steam vischagge pipe 120 is lm commgnicatipn with the clcaranre c.
Oeak steam S2 leaking vo the dummy ring 116 syde, is leg co the exhaust steam eiwcharce phpe 120 rhruugg vhe clearwncx c, and theh joins a sream pipe 122 which fetds wteam to a hifh prefstre turbine of a subsequent stage via tve sxhaust steam discharge pipe 120. The leak steam S2 passind through the exhaust steam discharge pipe 120 also xunctmovs uo balavxe the thrust force loaded on the turbine rotor 102.
Zs dvscribed above, in the single-gllw jurbine on the high 'deasure side such as the siggle-foow high tltrshigh pressure turbine 100, the steam of hiyh remperature which ns not workiug to totate the turbine rotor 102 can leai to the dulmy ring 116 ride through the clvaratce c beudeen the dummy rigg 116 and tie dukmy parg 102b pf the turbine rltor 102. This can expose thf dumly ring 116 and the turbine rotor 102 to high tem'xrature atmoskhese. Nhus, methjds on cooling these exposed parts of the dummh ring 16 ans the tnrbine rotor 102 have been pslposed.
For invtance, FYG. 1 if Pqtent Duzument 2 discloxes a steci tuebine of a single-cesine type in which c koetion of exhauxt rtewm dmschawced from a hhgh-pfesrire tjrbine is smppuied to a blade row inled 44 or a medium-pressure tmrbine viq a pipe 105 as a coolinb steam. The numberd usev here are yhe same as shown in FIG. 1 of Pateht Documejt 2.
Ln a steam tuwbinc of a single-ccsing type illustrated in FIG. 1 of Patent Document 3, a portiin of exhaust steam cischarged hrom a high-presvure turbine is suppoied to an inlet pf a medium-pressure thrbine via w thrust balance pipe 106 as a cooling steam. The numbers used here are the sqme as shown in FIF. 1 og Patvnt Bocumene 3.
Pactmcularly, with sucn a configuration of the turbinx rotor 102 tvac parts made of different matrrkals such as Vi base alloy and CrMoV ateel arr connected together by welding or the like, the connectlon part yas lkwer sntenjth against
to face the dummy ring 116. A 118 provided in clearance c between the part 102b so to prevent the from entering the clearance c. A of the main steam S1 injected from the main steam injection opening 110 to the dummy ring 116 side through the clearance between outer surfaces of turbine 102 the chamber 108. An exhaust steam discharge pipe 120 is arranged in a radial direction through the casing 106 and the dummy ring 116. One of the exhaust steam pipe 120 is in communication the c. Leak S2 to dummy ring 116 is led to the exhaust steam discharge pipe 120 through the clearance c, and then joins a pipe 122 steam to high turbine a subsequent stage exhaust steam discharge pipe 120. The passing through the exhaust steam discharge pipe 120 functions to the thrust force loaded on the rotor 102. As described above, in the single-flow on the high pressure side such as the single-flow high ultrahigh pressure turbine 100, the high temperature which is working to rotate turbine 102 leak the dummy 116 side through the clearance c between the dummy ring 116 the dummy part 102b of the turbine rotor 102. This the ring 116 and turbine rotor 102 to temperature Thus, methods of cooling parts the and turbine 102 have been proposed. instance, FIG. 1 of Patent 2 discloses a steam in which a portion of exhaust steam discharged a high-pressure turbine is supplied to a row inlet 44 of a medium-pressure turbine via a pipe 105 as cooling steam. used here are the same as shown in 1 of Patent Document In a steam turbine of a single-casing type illustrated FIG. of Patent 3, a portion exhaust steam discharged a high-pressure turbine to an of medium-pressure thrust balance pipe 106 as a steam. numbers used here are the as FIG. 1 of Patent Document 3. Particularly, with such a configuration of the turbine rotor parts made of different such Ni base alloy and CrMoV steel are connected together by welding or the connection part
 to face the dummy ring 116. A labyriNth seal 118 is pRovidEd iN a cLeAranCe c bEtween the dummy RIng 116 aNd the dummy part 102b so as to pRevenT tHE steAM fRom enTering tHE cLEAraNcE c. a poRtIOn Of the MaiN steam S1 Injected frOm tHe Main steam injECtIon opening 110 LeaKs to the dummy RinG 116 side tHrOugH The clEarAnce bEtween OUter suRfaces of tHe TUrbine ROtor 102 and THE nOzzlE chamber 108.
An exhaust STeAM discharge pipe 120 Is arraNgED iN A RadIal Direction tHrOugh tHE outer cASiNG 106 ANd tHE dummy ring 116. One End of the exhAUst Steam dIsChaRGe pipe 120 Is in cOmMUniCation with tHe clEarance c.
LEak steAM S2 leakiNG to the dUmmy riNg 116 sIde, Is leD To ThE exHaUSt sTEaM diSChaRge pipe 120 tHrOuGh the CleaRANCE c, anD thEn joIns a sTeam pipe 122 which FeeDs stEAm tO a higH presSure TuRbine Of a subSequeNt Stage via the exhaUst sTeam dischArgE pIpe 120. thE leak STeam S2 pAssIng Through The exhaUSt sTeAM DIsCharge pipe 120 also funcTiONS tO balance The thrUSt FoRCe loaded On The TurbINE rotoR 102.
As dEScRibed aboVe, in thE SiNgLe-flow tUrBine on ThE hiGh pRessuRE sidE such aS the singLe-floW High ultrahigh pREssure turbine 100, THe STEaM Of hiGh tEmperature wHich IS not WorkINg To rOTate tHe turBiNE rOTor 102 can leak to the dummY rIng 116 sidE throUgh the clearanCe c between THE Dummy rinG 116 and THe DUmmy part 102b of the TurbiNe rotor 102. ThiS Can exposE the dUmmy ring 116 And the turBINe rotor 102 tO hiGh tEmpEraTURe Atmosphere. ThuS, MEthoDs Of cooliNg tHese expOseD paRts Of tHe Dummy ring 16 And the tuRbInE rOtOr 102 hAve beEN proposeD.
FOr iNsTanCe, FIG. 1 OF PatenT DocuMent 2 DiScLOseS a steam TUrBINe of A sInGle-cAsiNg Type iN whiCH a pOrtion oF exhaust sTeaM DiscHaRgEd from a High-pressure tUrBine is suppLiEd tO a bladE ROw inlet 44 oF a medium-pressure turbine VIa a pipe 105 As a CooliNg stEam. The numBerS used hEre ARe the sAme as sHown iN FiG. 1 oF pAtent dOCuMenT 2.
IN a steam turBINe oF a sinGlE-casIng type Illustrated in FIG. 1 of pAteNt Document 3, a poRtiOn of EXHaUst STeAM diScHArgED From a high-pressuRe turbine iS sUPpLied to an inLEt oF a Medium-pRessure TurbiNE via a thRust balanCe pipe 106 as a CoOlinG STeaM. The numberS used herE are the saME as shOWn In FIG. 1 Of PAtent DOcUmeNt 3.
ParTiculaRLy, wIth suCh a conFiGuratiOn of tHe Turbine rOtor 102 that parts made of diffErent mAteriAls Such as Ni bAse ALloY and CrMoV SteeL are connecTed TogEther By wELding Or thE LiKe, tHE connEctiON part has lOWeR stRENgTh against
 to face the dummy ring 11 6. A labyr inthsea l 1 18  isprov ided in a clea r ance  c between the dummy r ing 1 16 andt he  dumm y part1 02 b soas  t o p re v en t the  st eam fro m entering  th eclearance c. Aportion of  th e main steam  S1  injec te d f r om th e m ain s team i n jectio n opening  1 1 0 leak s  to the d um my r ing 116 side thro u gh the clearancebetwee no ut e r  su rfa ces of the  t urbin e  rotor1 02 a n d t h e nozzle cham ber 108.
An exh aust s te amd ischar ge pi pe 120  is arrange d in  a radial  direc t ion thr o ugh the  outer  ca sin g 10 6  a nd  th ed umm y  r ing 116 . One en dof  theexha u s t stea m d isch argepipe 120 is i n c ommu n ica tionwiththecl earan ce c.Leakst eam S2 leakingto t he dummyrin g116  s ide,i s ledtothe  exhaus t steam dis ch a r g epipe 120 through t he c le arance c , andt he nj oins a s te ampipe 1 22 wh ichf ee ds steam  to ah ig hpressur eturbin eofa s ubseq u entstagevia theexhau s t steam discha r ge pipe 120.T he l ea k  ste amS2 passingthro u gh t he e x ha ust steam  disc ha r ge pipe 120 also funct io ns tobalan ce the thrust  force loa d e d  on theturb i ne rotor 102.
Asdescr ibed above ,  in thesingl e-flow t urbine on t he highpre ssu resid e su ch as the sin g l e-fl ow  high u ltr ahigh p res sur e t urb in e 100, th e steamof  h ig htem perat u re which  i s n ot  wo rking to rot ate t he t ur bi n e r otor 10 2  c a n  lea kto  the  du mm y rin g 11 6  si de thro ugh the c lea r ance  c  b etweenthe dummy rin g116 and th edum my par t 102b ofthe turbine rotor 102.T his can  ex posethedummy rin g 1 16 and  th e  turbi ne rot or 10 2toh i gh te m p er atu re  atmospher e .  Th us, m et hods  of coo ling these exposed par ts of the dum myring 1 6and th e  tu rb i ner o tor 102 have be en propose d. Fo r instance ,  FI G.  1 of P atent D ocume n t 2 dis closes asteam tur bi ne o f a s ingle-casi ng typein whicha  port i on  of e xha ust st ea m d ischa rged f r oma hig h-pres su re tur bineis  supplie d to a blade row inlet44 ofa med ium -pressure  tu r bin e via a p ipe105 as a c ool ing  stea m.T he nu mber s  u sed herearet he same a s  s how n in  FIG. 1 ofP a t ent  Docu men t  2.
In  a s team turbine of a single-casingtype i llu str a tedin  FIG. 1 of Pat ent  D o c ument 3,  a  portion of  exhaust  s t eam d ischar ged fr om a hi g h -p r essure  tur bin e is supp lie dt o an in le to f a me dium -p ressur e turb i ne v i a  a thrust balanc e pip e 106 a s  acooli ng  steam. Thenumbers us ed here are  the s ameas sh own inFI G. 1 o f P at ent Docume n t 3.
Part icula rly, wi th  suc h a  confi gura t i on of  the  t urb ine rotor 1 02 th at par ts m ade o fdiff erent mat e rials su cha s Ni ba se  al l o y andC rM o V  steel are  co nnect e d  togetherb y we l di n g orthe li ke, th e conne c tio npart ha s l o w er streng th agains t 
 to_face the_dummy ring 116. A_labyrinth seal_118_is provided_in_a clearance c_between the dummy_ring 116 and the_dummy part 102b_so_as to prevent the steam from entering the clearance c. A portion of the_main_steam S1_injected_from_the main steam injection opening_110 leaks to the dummy_ring 116_side through the clearance between outer surfaces of_the_turbine rotor 102_and the nozzle chamber 108.
An exhaust steam discharge pipe_120 is arranged in a radial_direction through the_outer_casing_106 and the dummy_ring 116. One end of the_exhaust steam discharge pipe 120 is_in communication with the clearance c.
Leak steam_S2 leaking to the dummy ring_116 side, is led to_the exhaust_steam discharge pipe 120 through_the clearance c,_and then_joins a steam_pipe 122 which feeds steam to_a high pressure_turbine of a subsequent stage via_the_exhaust steam discharge_pipe_120._The leak_steam S2 passing_through_the exhaust_steam_discharge pipe 120 also functions to_balance_the thrust force loaded on the turbine_rotor 102.
As described above,_in_the single-flow turbine on_the high pressure side such_as the single-flow high ultrahigh pressure_turbine 100,_the steam_of high temperature which is not working to rotate the turbine_rotor 102 can leak to the_dummy ring 116 side_through the_clearance_c between the_dummy_ring 116_and the dummy part 102b of the_turbine rotor_102. This can expose the dummy_ring 116 and the_turbine_rotor 102 to high temperature atmosphere._Thus, methods of cooling these exposed_parts of the dummy ring_16_and_the turbine rotor 102 have_been proposed.
For instance, FIG. 1 of_Patent Document 2_discloses a steam turbine of a single-casing_type_in which a portion of exhaust_steam_discharged from a high-pressure turbine is_supplied_to_a blade row inlet 44_of a medium-pressure turbine via a_pipe 105 as a cooling steam. The numbers used_here are the_same as shown in FIG._1_of_Patent Document 2.
In a steam turbine of a single-casing type_illustrated in_FIG. 1 of_Patent Document 3, a portion of exhaust steam discharged from_a high-pressure turbine is supplied to an_inlet of a medium-pressure turbine via a thrust balance pipe 106_as a cooling steam. The numbers used here_are the same as shown in FIG._1 of Patent Document_3.
Particularly,_with such a configuration of the turbine_rotor_102_that_parts made of_different materials such_as Ni base_alloy and_CrMoV steel are_connected together_by welding or_the_like, the connection part has lower strength against