H. L Sumner, Jr. Southern NuclearVice President Operating Company, Inc.Hatch Project Post Office Box 1295

Birmingham, Alabama 35201

Tel 205.992.7279

SOUTHERNhSeptember 12, 2003 COMPANY

Energy to Serve Your World

Docket Nos.: 50-321 NL-03-193250-366

U. S. Nuclear Regulatory CommissionATrN: Document Control DeskWashington, D. C. 20555-0001

Edwin I. Hatch Nuclear PlantMeasurement Uncertainty Recapture Power Uprate (MURPU)

Post MURPU Steam Dryer Performance Monitoring and Inspections

Ladies and Gentlemen:

By letter dated December 19, 2002, Southern Nuclear Operating Company (SNC)submitted to the NRC a license amendment request for the Edwin I. Hatch Nuclear PlantUnits 1 and 2. The proposed amendment increases the authorized maximum power levelfor both units from the current limit of 2763 MWt to 2804 MWt. Although the requestedpower level is a 1.5% increase above the current maximum power level, it will represent a15% increase above the original maximum power level.

Recently, the NRC identified issues in Information Notice 2002-26, Supplement 1"Additional Failure of Steam Dryer After Recent Power Uprate," related to the potentialgeneric implication of extended power uprates with respect to steam dryer failures. Hatchhas been operating at extended power uprate (EPU) since 1999 for Unit 1 and 1998 forUnit 2. The EPU power level represents approximately 113.4% of the original powerlevel.

By letter dated September 4, 2003 (NL-03-1798), SNC described actions in response to theimpending revision of General Electric SIL-644. On September 5, 2003, General ElectricNuclear Energy issued SIL No. 644, Supplement 1 "BWR Steam Dryer Integrity." Thecommitments noted in the September 4, 2003, letter are superseded by compliance with SILNo. 644, Supplement 1.

This correspondence is to notify the NRC that SNC will implement GE SIL No. 644,Supplement 1, Recommended action 3 (BWR/4 and later steam dryer designs) as outlined inthe services information letter provided by GE with respect to the Unit 1 and Unit 2 SteamDryers at Plant Hatch. SIL No. 644, Supplement 1 is provided as an enclosure to this letterfor your information.

4 oX\

U. S. Nuclear Regulatory CommissionNL-03-1932Page 2

This letter contains no NRC commitments. If you have any questions, please advise.

Sincerely,

H. L. Sumner, Jr.

HLS/whc

Enclosures: Enclosure 1 - SIL No. 644 Supplement I

cc: Southern Nuclear Operating CompanyMr. J. D. Woodard, Executive Vice PresidentMr. G. R. Frederick, General Manager - Plant HatchDocument Services RTYPE: CHAO2.004

U. S. Nuclear Regulatory CommissionMr. L. A. Reyes, Regional AdministratorMr. S. D. Bloom, NRR Project Manager - HatchMr. D. S. Simpkins, Senior Resident Inspector - Hatch

Enclosure 1Post MURPU Steam Drner Performance Monitoring nsections

GEtNucter EnerSILLS;= Woesiibnffoa Lef ter

_____- ---------------- r ----

BWRM steam dryer Integrity

SIL No. 644 M . 64 WSRJ sta dy failtre3rSu MWnt f iswed Augst 2102, dsribed on vcw at a

BWRJ" h t inthovcd 6c 4eOta steam dim&PwabstB. 203 ma Omtimin6c gnaof parta,

somn of wLich Cic Mratd Into a main steamliac (MSL). Uc mocat pruhbabe c=s of bvtwa Wuidcstnifiad a a flow 1imc biabl4i* sulte in ldcatrdi, I igh cylehigh

pSaEWladirigs b cg r the WISL nozls. Uchig~h vbaoystrses1thce pzs bladingovantualhy rmlled in &c high CyLe fatigucWlre of tc cower ptdc.

SlLNo 644NW. aica onltb plants withBW RA-*tyl stam drye, nd,:drmmcdatimWs forsionitoring moiiturccontent aid oerw wder practs ad foribosc planb operating at gratcr Oan the originallicesed herual pvr(OLTP), an pction of* e cor platcs St c uext SWe ing ouage,L c purpoefthis vpplcmcnt I b

5ML N 644 is to descib a wcond aC= dkfalr 9a ourcd at the mnic BWIRapproximialcly oanc yur ollowing th intiastc=amdrycfAflcme nielocaticson olc fagiur(ftf lo Figure 1) amd *e mat cms wamd rn than tealicr failure. As£ rsult.additiona onitouing amd inspoetioan arcecommandcd fr Al B11R plants ht arc

Ooerating. or Pln to operatc, t pOWer kvesgrtrIion the OLTP. SIL 644 ladpi toqBitrxv~lc -' drfyar designi. ThisSumppfrine I In SL No 644 prsets n vied

cm endations forplants with B"lVltylcteam draye and prtnidas Meome

applicale to plants wilh BWRI4 and lar steamdryer dsignsaDI&CUzSSIan

On April 16,2003, with Mc plant oprting atczwcndd Pinr upnac (EPLI couditions. amnawua openn Or.fa pilot operad ri

valve (P0RW)Cocmd. Theunitwas awdowt an ItA PORP mabcd. Ou 16y 2.2003,following rain to EPU condions, apeller$han fowild incrsc in the Moinairugew niwa incuzar lie mostun = omient contuedlo graulllly ea= until it eceded a pie-detemined thuehold of 0i3% onMay 28,20(1E3 The povr evOl was beduced top-EPVI endituo tht reulte in a moistuecontent reduction*t 0.% The mCIsu contentremained say at this valie following Ascpowe reduction wish so signiicant ohmiges inoahericactorwqg paramte observe byA operators.A detailed statistical evaluation of key plant

araneters conclude " aa subtle change in theAL gom w occurred following thApril 16 210 PORV vant. Based on Wiainformation, concunrnt with the moisturecontent increae, AC stility clcted to ahutdownthc unit n Jumn 14 2003 axd p rim satamdryer inspocticm.

DWailted visualnspcti of Ac accssiblcexternlmdd citra wer f Ihc steam dcreMr ad ignifrwt steam de damage Midamrae was most svere on Ac 90-d1 addof hc steam dr. the side Ihat was cloest SoAic PORV that hid opnand O0 Mc 90-dgeaide, a tIrough-wall cack apprximatcly90 inches log and ap l o e inchcs wide wasob d inhc lop of c uter had cover platcand c top ofthc vetical kWoplate(rfcr bFigurr 2). T e internal nes in dhe outerhod wir dcted and one in brawe i Ac

utrler ood was svred. The deached bmcww foundon top of Ac sarnm r ,ap r. Allddtached plswu accounted faraditrievdOu the oppoxitc aide of Ac deam dryer(2704cc ad) incipient acking wasobsered.on the inside ofth oter hood cover

Page 1 of 10NL-03-1932

Enclosure 1Post MURPU Steam Dryer Performance Monitoring Inspections

SIL No. 644 Supplement I page 2

plate and one vertical brace in the outer hoodwas cmcked No damage was fiund in the coverplates that had been replaced following the firststeam dryr ;lure in 202.Three tic bars on top ofthe steam dryerconnecting She steam dryer banks were alsocracked. Tie bar cracking has been observed onseveral other steam dryers (including plants thathave not hiplenet EPJM); therefore, tic barcracking is believed to be unrelated to tie otherdamage noted above.

R cause fsteam dWrfatlureExtensive metallurgical and arnayticaleauations (ezg detailed finite dlementanalyses. flow induced vbation analyses,computational fluids dynamics analyses,J1 6C scale model testing and acoustic circuit

analyses) concluded that the Toot cause of thesteam dryer ailure was high cycle fatigueresulting firom low fiequency pressure loading.There are two potential contributing factors tothe failure:

I , Continued operation for approximately 1month following the Ihiled cover plate in2002 which resulted in additional stressloading on the vertical hood plate, and

2. Inadvertent opening ofthe PORV resultingin a dnpression wave which subecdthe steam dryer to two to three times thenormal pressure loading. (It is believed thatthere was incipient cracking in the steamdryer and the PORV event caused dte cracksto open up).

The root cause identified in the first steam dryerfailure was high cycle fatigu cause by highfrequency press loading. The low froquencypressure loading was identified as the dominantcause in [his fidlurc. The law frequencypressure loading may have also been asignificant contributing factor in the first failure.

SMcam drI wer modkcatkmsThe following repairs and pre-enptivomodifications were made to both the 90 and270-dgrec sides of the steam dryer:I. replaced domaged % inch outer hood plates

with I inch plates

2. removed the internal brackets dita attachedthe internal braces to the outer hood

3. added gussets at the outer vertical hood plateand cover platcjunction

4. added stiffeners to the vertical welds andhorizontal welds on the outer hood

The comrbined effect of these modifications wasto increase the natural frequency ofthe outerhood, reduce the maxmum stress by at least afacor oft*, and reduce the pressure loading byseducing the magnitude of vortices in the stesnflow ac the MSs

Following the steam dryer modifications, thounit was returned to service on June 29, 2003.

G(nerk lmpleatkms

There are two key attributes that determine thesusceptibility of a particular plant to steam dryerdcgradatidn The dominant attribute is the staundryer configuration. There are three generaltypes of steam dryer configurations (tefer toFigure 3):

I. BWR/3-styl steam dryers with a squarehood and internal broccs. This designresults in maximum stresses where theinternal brces attach to the outet hood. Thecrack initiation at the BWIU3 occurred atthis high stress location Higher stressesresult ina greater susceptibility ofthecoaporents to crack initiation. SoneBWR/3-styic steam dryers do totincorporate the internal braces. This designeliminates the strss concentrationassociated with the brace attachment.

Page 2 of 10NL-03-1932

E Enclosure 1Post MURPU Steam Dryer Performance Monitoring Inspections

SIL Ml. 64 Supplement I -page 3

BWR/24syk *yr also hav £ Nhood.ow vc. thc wntrn Coursion ofthm 6mbanks nd hoo support s tiffcrtfm the% I J3-stvled*=.

2. BWR/4-le s dry ha santdhods. Tims dmpi rlud th 0itbra= wih intv plats that xubstanti^rduced xc mamum calculed Omrss

3. Bw'SIJm ata YCrdesinm s_isp Wcd mcd bhoods eD ptimisml ti'

Se flow. This desagn =tid thWas Wptmrfflrredoehi; ticOtimum Callted dtrss.

Th swand gmiribt is bw mcmum MLSetcm vlocity. The BWR/3 vnit tecpiemccd th tem dqycr znape has unit(20 inh diammter) MSLs ad comsqwmy 6chishes sm veocitics et EPU wondgtins ofmxyBWX WgleMSL eaocitvina the mplitud aoftlw hubied midscwustic fod facing funCio do kad to bi

Using dhs ru= Om Unbutos, a mroigmtiwas dvloped for o11 BWRs- An assmnt ofc lci suri rsuts supports thc

oason tlahe 1W kl sam dioyr ismoost mmptbi b swam dowdstuaq. Thisasesmnt wncludcd to ther steam dr -dcsigns WC sbstantialy lss wsscptibl to

eam ycrdamagc *b camparcd to fteBWWZ unit tt exeiced AC tem dzyerfaiure. Conscquently, so swgnimt nier damage is ctd for BWR4 and lotftm dim esin. aen at PU conditosNo BWR"2 lus h nevatd for EPUCsonditions P t

Recammended acton:GEX NudEm=Vexjrmmomiedxthst eimof3E BWRs wasidcr th fWing if curentlyopertins, or Planning to Opeura, abuvCfOLTP;

1. BWRA3tyc steam drycs with ielbrsa iOthm autohood:

*, levicw asvilablc vida inqocaiocrds to den ciiream rS)proet GAIS Or Wndeta d weIdsin the aove plate mud cute hood

br mecas moistue cmnte adctind by Na-24 neascuteuts inh Or water gnd cmdsr ho1wo,

establish a bselie valuc foropnaia mcar mavdximum cm themalpow'op= xg conditins. Iercand teord ft mitur content to arsoltion (Oltorsmallmer. Wsoate(or acewit for) now ihrough pahsWUre seAWr rcan Mo drty IOh ho*WIll (O.gS.eorrcWtrcteaCWup

' tflw, sample lines),Esalish re orpsurrcvtr lv lCSdeI flw., and dwatcr flow Wvacanxistent we balinc moistumr

-Ort values Moistur cont cmchane dring tMc peating cycl du kochanges in wc powr, c now, orcomraudial PA*i.

c. Monitor eactorprcssuro. wtcr lkVel,individual stcamliae flow, and Wevgerfow an a daiy bss fbr sinifiscantanomsalics (such es t changes in

dicad vals) t lay indicot edtead erm& lurm Monitrmidcompre indicatios on ach insrumentrf:nmce lg-. a drflure near Omtoforc= kl t1ap way vht IkeWi dtonsforthicsns on uttnfenc kg. The sp anges ihtwerc obsre duig h 2002 omwplate ail wre usually small (2-3 sfor ratore prssur, -to inches forractrevd, -6% fors wnmlinc flowr)erer. tn plots afthe data will beal furporfonmingte omnu d

Monitoring.

Page 3 of 10NL-03-1932

Enclosure 1Post MURPU Steam Dryer Performance Monitoring Inspections

SIL No. 64 Supplement I page 4

4L Impcmmw: a iaisturc coutwtmoniing program thjt m=sMiOto cntro at last We pr wkff a sigafficant change or a steailincreasing treid is obwrvd, monitormoistaur contcut daily Mid cvaluatmont plamt mwncus or "ants amdassooia plant P brmdcrs to Went*Ibc cauu; cuse on e wf e ead:

somstrw; contet cannot bodccrunuscd,considr roduction in powr or an

vrdrb plait shutdown for inspetion.

TMe moistur content action ovd fibrinitating te uncreaso monitoring andwevations mat ho dactmiewd fim theob=YW basolincalsoe and wormalVariations. Fwr Owuple. an snemoisturc zaiiyoicrctr.2 would bc aignificat dngc firr in efficictdor

(maranal moisture cmrAmgvr of -O,O3%)Forapa plint t opratcs %ith highsmoistuvolsi an obsmcd aOiscaryorr OJ% hig;bd tan the mama

nge would be cniVant yFollowing a Umiscut Own± t mw aymult in PMs= loadingeofbc camn

dzycr (seif va peig turbine slopvavew Closure. ste.) monito moisurcontent dail until thc structuralintegrityO of se er is conrfmnod.Onc it has bee astablislhed fht "hdqacrhas sustained .o demageczoatincmonitoring mayv bircuac-

0. Prfoam a visualinspcclion Ches61ffr VF-l)ofthdeutca kwycr lit t

ost itAsoubc rcfeing cutae Thisiasptoun sould includc t*C mostanscwtibic locations as deemined bv adryer of ss ainalysis (crcerto Fgurc 4)This inspocton should includ both ancxnexal and initcral inspectioa ofthe

asible aas. Rcmove tappodbubbies to cnsum compklt uovncra ofintal mWS

f R visual inspcctio in L.e atmubscw refucling outrics.

Not: Thc rornmcndations 4ab superoedcIhc rccommenIdations in SIL No. 644 forSWR3-sWicestc= dryers.

2. BV=-tWylc otcam drycrwith so hatrualbrac in theoutorhood:

ha huplancnl rcommaedtons t.c, Lb

b. Inplacnt a moisture contentmonitong Program at m sursmoisturc ontcnt at Iast onc cvcry Iwo(2) cks whn oprating ibov thcOLTP, If a igniicat change or aOaftdiy easing tevd is obse d,: Valate. recent Plant RmXan=V orvnts and associatd pWt parauntcrx

to idcuii Ihecmus=of" eincasedmoisturccont cat thcawuseofincrasod aioisturecoutcnt cannot bedctemidcoansidcra wduction inpmvroran oeady plant shudwtd for

:Umi lcoafnt ctio kva for-thc incd monitoring andevaluaions moust be trmind from thcobservd Anlinc salucs and -ormalvariations. For cxwnpic, obsnrvedmoisture yrvcreofOA2% would b asignifcat cdangc for in cf&icntdryor(normal moisturccarryeomc-00%For plt a h t opcs with highmoistwure Icls, an dbscw moisturecaryowr 0.1% kishcr than tbc normalrang would be significent.

Folom*g a bransict cvent at mayrsult in psur l ing of stcamdryer (riWvalve wping turbine p

lvs vlosuor, ct, monitr misturccontent daily nt the structuralintegrity of the drymris oonimd.Oncc it bas been astablishcd tuht Ohmdryar has vstaind so damnge. soutine

niiitoring ma bcmeumcd,

Page 4 of 10NL-03-1932

Enclosure 1Post MURPU Steam Drner Performance Monitoring Inspections

VL Mm. 644 Supplement I -pare 5

c. Patbicm a Visual inspe~ction ("bescfixrVT-l)atthcaztpp toinitialwqcrationabowie Trpertthe nest Kileduted clicling outage ifahcmmy operating ibove the OLT?1. Thisinspcction should incudc the mosdsusceptible kiestiouns an dekTrmined by a

* du a t a an al r tpsi eTkis inspection cm be limited to anexateia inspeetion of the mostsusceptitile locations.

4. Rqx hnvsualcct ion in 2catovay cobtherkufiline outage

3, BMWRM nd lcate Ukr sem d c jigs:l inpimenutrocmmedatioslu.p.116and Ie.

b. 2nkwrcczcidto b.flo%-crs the maisslum cmiet-

mo foing fluque can lic sciaxod to51CCpwrmon

c, Poirasm a Vial inpection (rwstfefi " VT-1) o initia oprionoIbc OL1T orwithin the next hwo

chduked Ibting outges if ahuadyopeting abose *C OLTP. Thisinspection sold Inld the mostsuwcpil locations as determind by adryor ss analysis (fcrto Figum 6and 7), inclhding the vertical sib sman eadc ofthc Outer hoods and di endplate on the two outermost banks. Thisinspoctio cm be limited bo an cxknalinspetion of the most suseeptible

pcutions.

d. Repeat the risual Inspcclions in 3i atevay goh PA~eing outagc.

Ntec: The inspection ecommendtion donot supecedcoisting pt6W Frmmquiments orcOh inspctonsrewomxmend an a insult of indnstuy*ogxpa,

To ueweidditional informationon hisubjecdoujr AKsibstancl n implementing arcummedAimpleaseonwtayourlocalGENulerEnergy Service Rqxrwntative.

This SIL pnais ly to GE BMMz. Theconditions mndorwich GE Nucler Ergyissues SIL& arc gted in SILo. 001Reiusion 6. the prvsos oftdich aencpoad into this SIL by xfbmucc.PwductrefouanceBll -ReactorAssembB13-Ractor Systcm

tsuedby

BSrndette GOdc Bohn. Pogrm Manager&wneex lron CommunicationsGE Nuclear Enco175 Cafncr Avenue

San Jose. CA 95125

Page 5 of 10NL-03-1932

A I

Enclosure 1Post MURPU Steam Dryer Performance Monitoring Inspections

SIL No 6U Supplement I * page 6

Fase I - Siaam DMyre Fa Loatns 20 and 20

Page 6 of 10NL-03-1932

Enclosure IPost MURPU Steam Dryer Performance Monitoring Inspections

$fL Ao. W" $qpplemenf I * page 1

rig=r 2 - Stem Diyer DamWg 90 Depw SWd

Page 7 of 10NL-03-1932

Enclosure 1Post MURPU Steam Dryer Performance Monitoring Inspections

SIL No. W Supplement to .peg B

kxebwdb-*lHood

&CCAU~wwM

A

:1I

I

I~~N~

6nwAN~oaw"esig"o

Squaiw HodiSWR35t.DesIg"

fianted HoodsOW t D-V

Fi~um 3 - Ste,* Dsryt Hood Confirtmions

Page 8 of 10NL-03-1932

I; . 11

Enclosure 1Post MURPU Steam Dryer Performance Monitoring Inspections

$1L Hoe 6&4 Supplement I .pege 0

Fi'WM4 -*WihSbIMMLOCaaioclqwwc Hoodwiibd Bm=e

111g Sires,

,00~ ~~ Lecations

IFaWm e- Tih Suva sLAcc~tinSqwm ood,.wdhoutBiram

Page 9 of 10NL-03-1932

i I -,

Enclosure 1Post MURPU Steam Dryer Perfonnance Monitoring Inspections

SMLNM 6" SupplementWl .age VO

Figue 6 - liigh SU= LocationsSlanted Hood

Figur 7 -High SU=es LocationsCwvd Hood

Page 10 of 10NL-03-1932