97122 double-shell tank remaining useful life estimates (51300-97122-sg)

Paper No.122

DOUBLE-SHELLTANKREMAINING USEFUL LIFE ESTIMATES

R. P. Ammtatmula and P. C. OhlLockheed Martin Hanford Corporation

Richland, WA 99352

ABSTRACT

The existing 28 double-shell tanks (DSTS) at Hanford are currently planned to continue opemdionthrough the year 2028when disposal schedules sbowremoval of waste. ~Lsschedule will place tie DSTstia semicelife wtidowof4Oto6O yearsdepending ontankconsbmction dateandactual rctircmentdate. Tbi8paperexamines comosion-related life-limiting condhionsof DSTS and reports the results of remaining useful life models developed for estimating remainiig tank life.

Three models based on controllable parameters such as temperature, cbemisny, and relative humidity are presentedfor estimates to the year in which a particular DST may receive a breach in the primary tank due to pitting in the liquid orvapor region. Pitihgis befievdto betiehfe-lti]thg con&tion for DSTs, bowever, tieregion oftiemost a~essivepitig(vapor space or liquid) requires further investigation.

The results of the models presented suggest none of the existing DSTS should fail by through-wall pitting until wellbeyond scbeduledretrieval in2028. ~eesttiates oftibrewhye~s (tieyeu tiwbich atimaybe expected to breachtieprimq ttiwall) rmgefiom 2056for pitihgcomosion intieliquid region oft~ 104-AWto beyond the nextmillennium for several tanks in the vapor region.

Keywords: double-shell treks, usefillife esttiates, pitiingcomosion, cmbonsteel, vapor phme, liquid phase, Hmford,corrosivity factor

INTRODUCTION

The Hmfordsite mmages209,3 10m'(55.3Mgal) ofradioactive waste cmentlystoredti 149single-shell tanks(SSTs)and28DSTs. ~iswm@must beretiieved fiomtie tiactive SSTsmdprocessed tiou~tie active DSTsforeventual dkposal. ~eDSTsme essentially 6eestmdtig mild-cmbon steel prti~tis cnn@hed witimconcre&tiswitbmild-carbon steel linersi, Tbenominal capacity of DSTsis 1million gallons each. fbeactua ltotaloperadng capacity

Copyright@l997 by NACE International. Requests for permission to publish this manuscript in any form, in part or in whole must be made in writing to NACEInternational, Conferences Division, PO. Box 21834o, Houston, Texas 77218-8340. The material presented and the v!ews expressed in thispaper are solely those 01 the author(s) and are not necessarily endorsed by the Association. Printed in the U.S.A.

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of the existing 28 DSTS is 118,470 m] (31.3 Mgal). The DSTS were constructed between 1967 and 1986 with referencedesign lives of 50 years. The current long-term plamrbrg requires retrieval of wastes currently in SSTS by 2018 and retrievalof wastes in DSTS by 20282.

Table 1, tnken from Abatt, et al?, (modified by assum~g yenr of construction completion as service stat year), providesreference windows by calenda year for DST service lives. The expected retirement for current DSTS is some time between2012 nnd 2028 with fial closure sometime afier retirement. This time schedule will place the DST service lives roughlyin a 40 to 60 year window depending on the exact sequencing of tanks for retrieval.

fn 1995, a project to design and conshuct additional DSTS was tenninateds ba.vedon (1) assumptions that the wastevolume flow through DSTS could be managed below the current 118,470 m](31.3 Mgal) DST capacity through the year 2004and (2) an inkinl report on the remainiig useful life of the current 28 DSTSthat concluded there wns a low probability of DSTfailure before the yenr 2005.

Schwenk6 reported that various types of metal corrosion are the dominant aging mechanisms for the steel tanks andpiping. A DST Usefid Life Analysis] issued in March 1996 further refined this conclusion by identifying life-limitingconditions for the DSTS. TM analysis examined in-tank coupon data from SSTS, Iaboratoty data for both SSTS and DSTS,and literature tiomother DOE sites and private industry. Abatt, et al., concluded that pitting corrosion was the life-limitingcondhion for the DSTS. The present paper presents remaining usefnl life models based on three scentios for pitting corrosionin the liquid nnd vapor spaces of the existing DSTS. Abatt, et al., also reported that support components associated witi theprimary tanks, such as the concrete, and the secondmy containment liner, are expected to last well beyond the useful life ofthe primary tanks,

The DST usefid life estimates presented in this paper are intended to support long-term programmatic decisions suchn-sDST waste retrieval sequence and need for additional DST capncity. These estimates are not intended to support nem-termoperational decisions such as immediate chemical addhions to tanks. The DST usefnl life estimates are based on Hnnfordspecific laboratory data and relevant data available in the literature. It must be noted that baseline condition surveys of theexisting DSTS are necessmy to confm and refine the predictive models presented in this paper.

DSTUSEFULLIFEESTIMATEMODELS

Based on the information available today, the life-limiting condition for Hanford DSTS is believed to be a primnry tankbreach by pitting corrosion. Abatt, et al?, defined the term Failure as

DST Failure: A physical change in DST geomem or material properties that couldcause the tank to be removedfrom service.

In the context of this paper, the breach of a primary tank is a change in DST geomeby that could cause the tank to beremoved from service.

Three sepnrate models have been developed to describe pitting rates and estimate useful lives in the liquid and vaporregions of DSTS. The models are: Corrosivity Factor model, Atmospheric Corrosion model, and Condensation Corrosionmodel. All three models have valid technical bases, however, all three models also have significant uncertainties whenapplied to Hanford DSTS. Descriptions of the models and their technical bases are presented in the following along with adiscussion of uncertainties.

Hnnford carbon steel pitting corrosion data are presented in Table 2. It is important to recognize that this data setprovides less thnn conclusive information regarding parameters that affect pitting in the vapor space of DSTs. Liquid phasepitting shows a strong correlation with repnrted cnrrosivity factor (CF). The CF has been defined and discussed in detail byAnantatmula et al? However, the strongest correlation between pitting in the vapor phase and an experimental parameterappears tObe duration of the experiment. The vapor phase pitting corrosion rates vs exposure time data were fitted to a powercurve, and both the power curve and the data points are illustrated in Figure 1. Although the tit is not good (as indicated bythe value of the coefficient of determination

to be significantly higher than ON actunl DST service conditions, %nilcrly, RH values for SST coupon vapor data are notreadily available but are also expected to be sigrrflcantly higher than the actnal DST service conditions.

Corrosivity Factor Model Fnr Liquid Phase Pitting

DescriDhon. Calculates liquid phase pitting corrosion rate using CF

Pitting Corrosion Rate = a(CF)b equ. (1)

Failure Time = Construction Date+ Nominal Wall TbicknesSa(CF)b

where a=3.3 mils/yr, b=O.2, and CF is the corrosivi~ factor (Nhmte/~itiite+Hydroxide]),

~ i During the course of the DST Useful Life Analysisq, a strong correlation was identified for pittingin the liquid regions of DSTS and CF (F@re 2). It was assumed in Abatt, et al,3,that the condensed phase in the vapor spacemay behave similcr to the liquid phase below, nOowing the pitting corrosion rates in vapor space to follow a similarrelationship with the CF. On thk basis, a bounding value of a=12.7was obtained in equation (1) for the vapor space corrosionrates, with the b value the same as that for the liquid phase corrosion rates.

Further discussion cnd nnalysis of tie vapor space data in support of the present paper leads to the conclusion that hereis no correlation between vapor space corrosion rates and CF. This conclusion is based lcrgely on an examination of partialpressures associated with the ionic species of nitrate, nitrite, and hydroxide that indicates these species will not be fonnd asmajor constituents in vapor phase chemistry.

The results presented in Table 3 are for liquid phase corrosion based on the correlation presented in Figure 2. The wallWlcknesses in Table 3 are taken from the wall thicknesses at maximum waste height. The data in Table 3 indicate that theearliest DST breach by liquid phase pitting will not occur before the yecr 2056, which is almost 30 yews later than thescheduled DST waste retrieval date.

Uncertainties. This model uses a limited set of data over an extreme range of CFS. There may be more aggressiveeffects of nitrate in a film just above the waste surface resulting from the rise and frill of waste height due to changes inatmospheric pressure. More laboratory work is needed to determine if this effect may be significant, In addhion, emptilcaldata from baseline condition surveys such m those planned for the DST fntewity Assessment Program are necessaty forconflation of the model.

Atmospheric Corrosion Model for Vapor Phase Pitting

MC riDtion. Uses time, RH and temperamre to correlate tank conditions and corrosion rates.

Teclnrical Basis.. Incorporates considerations that are believed to be important tDvapor phase corrosicm

Lee et al?, developed humid-ti corrosion models based nn a total of 166 sets of atnmspberic corrosion data (up to 16yecrs) of cnst irons and cmbon steels which have corrosion behaviors similar to the DST steels. The data base for thesemodels are from various exposure condhions in tropical, urban, mral and industrial test locations. The test exposureconditions for the data collected by Lee et al., range tlom 5 to 27C average temperatnm, 63 to 85Aaverage RH, nnd 2 to406 pg SOJm average SO, content. Because SO, is not expected to be present in the DST vapor space at a signiticnnt level,the SO, term is omitted tkom Oremndel equation of Lee et al., (see equath (2) below) for the present atmospheric corrosioncalculations.

The following humid-air general corrosion model equation was developed by Lee et al., based on dependencies ofgeneral corrosion on humid-air exposnre conditicms obtained fmm the literature data.

in D, = % + a, In(t)+ @H + aJT equ. (2)

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where Dgis corrusion depth in pm, t is time in years, T is temperature in K, and ~, al, ~ and a~arc constants. Equation (2)can be solved fort as

t = exp ((In D, - m - %/RH - aJT)/aJ equ. (3)

Linear regression of the fit of equ.(2) to the data by Lee et al., yielded tie following parameter values:

+ = 16.9865 ~2.873al = 0,611310.0295~ = -893.76~231.04~ =-833.53 *381.97

For the humid-air pitting corrosion model, Lee et al., used a pitting factor, which is defined as the ratio of maximumpit depth to the general corrosion depth at a given exposwe time. From a review of results of extensive corrosion testingprograms in inland tropical environments in Panama, Lee et al., concluded that tie pitting factor ranges from 2 to 6. Thepitting factor was also ussumed to be normally distributed with a mean of 4 and a standard deviation of 1. For additionaldetails of the humid-air corrosion models, the reader is referred to the publication of Lee ct al., (Reference 9). For the presentDST atmospheric pitting corrosion calculations, equ. (2) above is used witi a pitting factur of 4. Because of the unavailabilityof RH data for the AN tank farm, a conservative value of 80/0was ussumed for all the AN farm tanks. Representative RHdata for the othm DSTS and vapor space temperamre estimates for all the DSTS were obtained horn Ammtahmda und OhI.

The results of the present calculations arc presented in Table 4. As can be seen from the table, the results indicate thatbreach of the DSTS by vapor space ahnospheric pitting corrosion will not occur until far beyond the end of their scheduledretrieval in 2028.

!JncertaintiQ. The RH is not the same for all the DSTSund there is uncertainty in the measurement of RH. However,the RH may be as low us 20% and is not expected to be over 80%. Although the aging waste DSTS were at boilingtemperature when they fust started receiving waste, the current DST temperature is a maximum of 66C. The vapor spaceis not expected to contain any S02 me model used for the present calculations dld not include data from marineenvironments, fn spite of the uncertainties listed above, the atmospheric pitting corrosion in the vapor space is not a causefor concern since the earliest tunk breach is not until well beyond the end of the scheduled DST waste retrieval in 2028.

Atmospheric Corrosion Model for Vapor Phase Pitting with 25% Condensing Conditions

~ i n. Uses results of atmospheric corrosion model in conjunction with similar aqueous corrosion model toestimate remaining useful life of DSTS subject to water condensing on the tank walls 250/. of the year.

Techuic- i fn addition to the atmospheric corrosion models, aqueous corrosion models were also developedrecently by Lee et al., using long-term corrosion data on cast iron and carbon steel available in the literature.

The following aqueous general corrosion model equation was developed by Lee et al., based on dependencies of generalcorrosion on aqueous exposure conditions obtained from the literature data.

In D, = b, + b, in(t)+ bJT + b,T equ. (4)

where Dg,t and T have the same significmce as before, and b~,b,, b! and b, are consti~Equation (4) can be solved fort us

t = exp ((In D, -b, - bJf - b,T)~J equ. (5)

Linear regression of the tit of equ. (4) to the data by Lee et al., yielded the following parameter values

b.= 111.506 t 10.804b, = 0.53210.0272b,= -23303.2 ~ 2296.2b,=-3.193 X 10-~3,526x 10-5

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Sinilar tn the humid-air pitting corrosion model, Lee ct al., modeled aqueous pitting corrosion by using a pitting factorwith the assumption that it is nnnnally dktributed with a mean of 4 and a standard deviation of 1. For additional details ofthe aqueoua corrosion models, the reader is referred tn Lee et al? As for the atmospheric corrosion case, for the present DSTaqueous pitting corrosion calculations, a pitting factor of 4 was used with equation (5). Also similnr to the atmosphericcorrosion caae, a conservative RH value of 800/.was assumed for all the AN farm tanks and representative RH dnta for theother DSTS and vapor space temperature estimates for all the DSTS were obtained from Anantatmula and OhllO.

The results in Table 5 abnw application of the atmospheric corrosion model (discussed in the previous section) and theaqueous corrosion model (discussed above) active for 75% and 25Aof the time respectively during the year. Even underthese conservative conditions, the mndel does not indicate a single breach of tank wall in the vapor space until well beyondthe end of the scheduled DST waste retrieval in 2028.

Ynce~ ti~. The RH for the DSTS may be aa low as 20% and is not expected to be over 80%. Although the agingwaste DSTSwere at boiliig temperate when they fmt stmtcd receiving waste, the current DST temperahue is a maximumof 66C. At these RHs and temperatures, aqueous conditions are not expected to be present on the tank walls in the vaporspace above the liquid waste. It k quite conceivable that some DSTS may have condensation on the tank wnlls in the domespace some of the time. Since the RH data of the DSTS gathered over the last few years indicate that 100ARH condhionsare only possible a few days during the year, it k reasonable to assnrne that aqueous condbions existed in the DST dome spaceonly for a fraction of the time (

Low Hydroxide Tanks

Hydroxide concentmtion (in the waste below), lower than that specified by the DST waste specification limits, is notexpected to significantly affect corrosion of tank wall in the vapor space. However, this condiion can be detrimental tocorrosion in the liquid phase of the low hydroxide tanks. Hydroxide, along with nitrite, inbibita the cathodic reactionassociated with nitrate-assisted stress corrosion cracking and nitrate pitting attack.

Relationship of Liquid Chemistry to Vapor Chemistry

It is well established that the primary constituents in the waste liquids are nitrate, nitrite and hydroxide. The watervapor evaporating fkomthe waste liquid is not expected to contain any of these components to a measurable extent. The gas(air) in the dome spnce primnrily contnins the water vapnr evaporating horn the waate surface combined with any t%nrmableor otier gases escaping ffom the waste. Since the DSTS are vented with outaide air sweeping over the dome space at 50-600cfm, the gases evolving i?om the waste cannot accumulate in tie dome space in sufficient quantities or durations tosignificantly contribute to vapor space corrosion.

However, moist waate films maybe present on the tank walls abnve the current wnate surface level of the tanks, wherethe chemistry ia expected to be somewhat sirniku to that of the waste liquid below. These waste films could be horn wastetransfers into and out of the tanks, the rise and fall of the waate surface in response to changes iu the barometric pressure,or a spray from running air Iifl circulators. In addition, gas bubbles escaping from the liquid waste below and bursting in thevapor space could deposit liquid droplets containing nitrate, nitrite, and hydroxide on the tank walls. It should be emphnsize.dthat these wnate films would be more dilute with respect to the major waste constitienta compared to the liquid waate below.This is especially true of the hydroxide, which is readily consumed by a reaction with the carbon dioxide in the dome air.

CONCLUSIONS AND RECOMMENDATIONS

Conclusions

1)

2)

3)

4)

5)

None of the models presented suggest au imminent DST failure prior to the completion of DST wasteretrieval in2028. ~ee~fiestpredtied tiou@wdlbreach istitilW-AW titieyew 2O56bypititigirrtheliquid region of thetank. Tbkestirnatei sconservativei nthatita asumedt hetankw aafilledu pintothe 3/8 thick region of the tank wall very soon afier construction.

The data available today do nnt suppottacomelation between current waste chemistry compositionspecifications in liquid phase and corrosion rates in vapor phase.

Emptilcal data from baseline condhion surveys oftbe DSTs isnecessary forconfmation of modelspresented. Attiktfie, tisuffLcient &tiexkt Wdevelopastigle memodelfor DSTmmtimgusefil life.Ammonia and chlorides have not been adequately factored intn the models or into the existing waatechemistry composition specifications.

Pitting corrosion is expected to be the life-limiting condition for DSTs. Further laboratory work isnecessary toquantify differences brvapor phaae pitting, Iiquid phase pitting, andliquidvapori nterfacepitting.

The models presented in thk paper only address corrosive attack for representative conditions in individualDSTS. Extiemecondtions suchmabnomal chemis@ ordefective fabrication cmotbemodeledadcmonly bedetected bysurveillance and inspection. Althougb themodels presented donotpredlct immtientbreach of DST walls, chemistry and tank conditions should be monitored for indications of change.

Recnmmendatinns

1) Perform baseliiecondkions urveysofDSTp rimnrytanks. Tbiscnnbeaccompliabed viathe DSTinte2r@aaacssmentprngram. Particular attention should be given tn lower knuckle rcgiona for evidence of cmckmgand quantification of pi!ling differences between liquid nnd vapor regions.

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1.

2.

3.

4.

5.

6.

7.

8,

9.

10.

11.

12.

13.

2) Adjust DST pitting experiments to reflect actual DST service conditions for temperature and RH. Theexperiments should also include the effects of the simultaneous presence of chloride and ammonia in thewaste liquid on the corrosion of the tank wrdl adjacent to the waste surface. Undw-deposit (crevice) pittingexperiments should be initiated to quantify pitting rates under srdtcnke and DST sludges,

3) Place vapor phase pitting coupons in at least one DST for retrieval at 6 mo, 1 year, 2 year, and 4 yearintervals tn verify models presented for vapor space corrosion,

4) Compare Hanford specific laborato~ data to similar data available through general literature

REFERRNCES

B. M. Hanlon, Waste Tank Surmnary Report for Month Errding November 30, 1995, Westinghouse HanfordCompany, Richkurd, Washington, WHC-EP-0182-92, Rev. O, 1996.

Ecology, EPA, DOE, Hanford Federal Facility Agreement and Consent Order, as arrrended, Washington StateDepnrtrnent of Ecology, U. S. Environmerrtnl Protection Agency, and U. S. Department of Energy, Olympia,Washington, 1994.

F. G. Abatt, R. P. Anantntrnula, N. G. Awadalla, C. E. Jensen, L. J. Julyk, P. C. Ohl, L. Muhlestein, DST UsefulLife Analysis, Westinghouse Hanford Company, Rkhhnrd, Wasbirrgton, WHC-SD-WM-ER-556, Rev. O, March29, 1996.

B. Knutson, P. Baymes,TWRS Mission Analysis, Westinghouse Hnrrford Company, Richland, Washington,WHC-SD-WM-MAR-O08, Rev. O, 1995.

C. E. Jensen, Multi-Function Waste Tank Facility, Phase Out Basis, Westinghouse Hanford Company, Richkurd,Washington, WHC-SD-W236A-ER-021, Rev. 3, 1995.

E, B. Schwenk, Evaluation of Remaining Life of the Double-Shell Tank Waste Systems, Westinghouse HanfordCompany, Richkmd, Washington, WHC-SD-WM-ER-432, Rev, O, 1995.

R, P. Anantatrnula, M. J. Danielson, E. B. Schwerrk, Characterization of the Corrosion Behavinr of the CarbonSteel Liner in Hanford Site Single-Shell Tanks, Westinghouse Hanford Company, Richburd, Washington, WHC-EP-0772, Rev. O,June 20, 1994.

Metals Handbook, Corrosion, Ninth Edition, Volume 13 (ASM International, Metnls Park, Ohio, 1987),p.512.

J. H. Lee, J. E. Atkiis, R. W, Andrews, Humid-Air and Aqueous Corrosion Models for Corrosion-AllowanceBnrrier Material, Scientific Basis for Nuclear Waste Management XIX, Vol. 412, p. 571, (Pittsburgh, PA:Materials Research Sociely, 1996).

R. P. Anarrtatrmda, P. C. Ohl, DST Remairriig Useful Life Estimates, Westinghouse Hanford Compnrry,Richland, Washington, WHC-SD-WM-ER-585, Rev. O,June 28, 1996.

C. H. Brevick, L. A. Gaddk, W. W. Pickett, Historical Tank Content Estimate for the Southeast Quadrant of theHanford 200 Area, Prepared by ICF Kaiser Hanford Company for Westinghouse Hanford Company, Richland,Washmgtorr, WHC-SD-WM-ER-350, Rev. O, 1995.

D.A. Hausmarnr, Materials Protection, November Issue (1967) p, 19.

R. P. Armntatnrula, DST Pitting Annual Report, Testing performed by M. J. Danielson at the Pacific NorthwestNational Laboratory for Westinghouse Hanford Company, Richlrnrd, Washington, WHC-SD-WM-PRS-O 16, Rev.O. 1996.

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TABLE1SERVICELIFEREFERENCEFORHANFORDDSTS

Service Life (Yrs)Tank

1996 2012 2028 2050

241-AY-101 through-102 26 42 58 80

24 1-AZ- I02 19 35 51 73

241-SY-101 tbrouSh -103 20 36 52 74

241-AZ-1OI 25 41 57 79

241-AW-101 throuSh-106 16 32 48 70

241-AN-10 lthroush-107 15 31 47 69

241-AP-101 thrOugh -108 10 26 42 64

TABLE 2PITTING CORROSION DATA OF CARBON STEEL OBTAINED AT HANFORD

Waste TyPe C.rmsivily Duration Temperature Pitting Pitting PittingFmJor (CF) (60urs) cc) Corrosion COmOsiOn Corrosion

L (mpy)~ (mpy) V (mpy)

Purex(Lab) 19.09 104 72160

Purex (Lab) 19.09 730 I 04 ND 242,190 8.47,300 4.8

Plum (101) 19.09 3,120 6.4 2.0

Redox (S-104) 6.53 6,570 82-127 5.3

BiPO, (Lab) 2,75 4,380 80 2.4 8.6ND 2.8 5.5ND 1.8 3

BiPO, (Lab) 2.75 450 102 (boil) ND 35 (ma.x) 37 (ma.x)

B,PO, (TX-1 05) 2.75 5,400 16(TX-109) 2.75 4 (m@ 2 (max)

TBP (Lab) 81.67 730 10 82,190 8 7

ND= ot detected L = Iiauid V = vavw IJV = liwidhapOr in*rfw TBp = WibuWlpbOspha~,.= no coupondata availalhe

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TABLE3DST USEFUL LIFE ESTIMATES USING CORROSIVITY FACTOR MODEL

FORLIQUID PHASE PITTING

Tank ThicknessCF(Max~ PittingBreachYea?(roils) Rate(mpy)

104-AW 375 5.85 4,9 2056107-AN 375 2.69 4.0 2072l 102-AN 375 2.37 3.9 2075*107-AP 375 4.13 4,5 2096101-SY 375 0.73 3.1 2099101-AN 375 0.73 3.0 2104105-AN 375 0.6 2.9 2109101-AW 375 0.57 2.9 2110104-AP 500 2.36 4.0 2111102-SY 500 1,63 3.7 2112103-AN 375 0,54 2.6 2112102-AZ 500 1,51 3.6 2116104-AN 375 0,46 2.7 2117103-AW 500 1,46 3.6 2120101-AY 500 0.61 3.1 2130102-AY 500 0.74 3.1 2133103-SY 500 0.86 3.2 2134106-AN 500 0.89 3.2 2137101-AZ 500 0.65 3.1 2139105-AW 500 0.78 3.1 2141106-AW 500 0.74 3,1 2143102-AW 500 0.73 3,1 2144101-AP 500 0.81 3,1 2146103-AP 500 0.79 3.1 2147106-AP 500 0.76 3.1 2146105-AP 500 0.74 3.1 2149106-AP 500 0.74 3.1 2149102-AP 500 0.6 2.9 2157Numberoftanksbreaching

r2078 0

Tanks recently operated or currently operating outside corrosion specification (Low Hydroxide Tanks)Taken from Abatt et al., (Reference 3)

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TABLE4DSTUSEFULLIFEESTIMATESUSINGATMOSPHERICCORROSIONMODEL

FORVAPORPHASEPITTING

T 0.18 1 25930.18 2593 II

Tank Thickness RelativeTemperature]PittingRate]BreachYear(roils) Humidity (%) (deg.C) (mpy)

t 102-AN 375 80 33

103-AN 375 80 33

104-AN 375 80 34 I 0.18 I 2584 H105-AN 375 80 32

,, 07-A.. --- -- .-

101-AI Lfu+

106-AtN } .JIU I uu I !< I . !- ! 2739102-AW I 375 75 24 0.05 >3000

0,17 2802

\N j 375 I lw I Jz 0.17 2802NI 375 80 22 0.15 --- A., I 97= I Qn I 40 n 4A

106-AW 375 73 34 0.03 >3000

104-AW 375 71 18 0.01 >3000

*101-AY 375 20 19 3000

*102-AY 375 20 17 3000

101-SY 375 51 16 3000

102-SY 375 63 16 3000

103-SY 375 57 16 3000

101-A2 375 43 55 3000

102-A2 375 43 49 c 0.01 >3000c 0.01 >3000

1 . I ,, 3000

300030003000

!22?E-11103-AP 500 65 13 ~ 0.01 104-AP 500 68 15 3000

105-AP 500 61 18 c 0.01 >3000

106-AP 500 64 17 3000

107-AP 500 62 15 3000

106-AP 500 66 18 30002028 0

Tanks recently operated or currently operating outside corrosion specification (Low Hydroxide 1ads)

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TABLE5DSTUSEFULLIFEESTIMATESUSINGA COMBINATION

OFATMOSPHERICAND AQUEOUS CORROSION MODELS

(roils) Humid~ (%) Temperature C.arrosion (roils) CorrosiQn (mil~) (mpy) Year

, ..C . . .-,.-5 7nn3

, .Wc.u

/.u(t+u

4n4.rm .76II ;:;1:, I :;: I ; I : 1

,.. .=... 1 .-m ... , _..ae.r.a. ... 0.6 2623,. L. r 0.5 2751)1 317 0.2 >3000

i

7.33E-13 375 0.2 >300019 8.87E-01 374 0.2 >3000

,..-,,, .,. ,. . . 0,.4=. I I .,

106-AN 375 80 19 1,48E+O: . . .

1044W 375 71 18

c1OI-AY 3755.78E+0

20 19

105-Aw 375 53

103-Aw 375 69 17 4.60E+OI I 329102-AY 375 20 17 8.82E-13 375

102-SY 375 63 16 1.63E+OI 1 . . .

102-AP 500 65 19 2.62E

103-SY 375 57 16 . ..

101-SY 375 51 16 O.UYE-U1

106-AP 500 66 16 3.46E

101-AP 500 64

106-AP 500 61 18 1,20E+OI I 488

106-AP 500 64 17 2.55E+OI 474

104-AP 500 68 15

107-AP 500 62 15 ...103-AP 500 85 13 A G7F.,,, , a..

Y0.2 >3000O.f >3000. .5 >30003000annn-3

30003000

0.1 >30000.1 >3000

-30003000Qfilltl

4 6,41E+OI I 436 I 0.1 >,- -T+IJ, 480 0.1 >:-.. . 1 . . .

I 0,1 >$...

l!! o II

T6nks recently operated or currently operating outside corrosion specification (Low Hydroxide Tanks)

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xx

x x.

x

xx x

,,

0 0.1 0.2 0.3 0.4 0.5 0.8 0.7 0.8

Years

FIGURE 1- Hanford vapor space pitting data vs exposure time

.

o 10 20 30 40 50 60 70 EO 90Corrosivity Factor

FIGURE 2- Pitting corrosion in liquid region

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97122 double-shell tank remaining useful life estimates (51300-97122-sg)

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