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NRC Tra'nslation7 2111:-

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Language of Foreign Document:- - RUSSIAN -

Translated Title of Document: SOLUBILITYLOF MAGNETITE IN T!!E' HEAT ~ TRANSFER-'

AGENT:OF A NUCLEAR'PONER' PLANT WITHBOILING WATER REACTOR-

Untranslated Title: . RASTVORIMOST' MAGNETITA V TEPLONOSITELEAES S KIPYAS11Ci!IM-:REAKTOROM-

.Ii

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;jAuthor (s): V. -I. - Z AREMBO , V.G; , KRITSKIY,

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A'. A . = S L O B O D O V ,' L'. V . P U C l! K O Vl

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> > -j/ Translated Name and Address KURCilATOV INSTITUTE-FOR ATOMIC ENERGY' -!of Corporate Author:: MOSCOW,_ USSR. -i

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[Untranslated Name and Address.

of Corporato Author: !

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Date of: Original Foreign Document: (NOT GIVE!1)

Foreign Document ID Number (s): 10-5i - 1

Number of Pages in Translation: 14 -

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Date Translated for NRC: MAY 1989

NRC Requester / Office: EDWARD SHOMAKER, GPA|

Translated by: S C'I T-R A N >

Nameand- 1482 EAST VALLEY ROAD :

Address SANTA,BAR3 ARA CA 93150

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9012O20161 890531REVQPNRQgRPDR

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Solubility of magnetite in the heat transfer agent offa' nuclear power pplant with boiling vater reactor

Zarehbo V.I,, Kritskiy V.G., Slobodov A. A. , Puchkov L.V.

I

. . . . 1.

.

. . . .

Certain demands are made on the organization.of the water-chemical !

.

mode. of nuclear power plants: the aggressiveness of the heat-transter-. agent must'be minimal'with respect to the structural materials;ofcircuits, contaminants must.be prevented from entering the!radioactivec q

. reactor core, and deposits must be prevented from overgrowingLthe core and' lheat exchange equipnient.

'

'

a

The use-of water of a high'degreelof1 purity as the heat-transferagent .of a boiling vater, reactor 1has eliminated the possibility. of_-

~

jf ormation of salt deposits, In this' case! corrosion products (CP) of' /3 !.

structural materials have become the main " scale formers": oxides of' iron,chromium, manganese,i nickel,. cobalt and their hydroxides.- A decisive rolein the buildup of radioactivity oncthe' surface.oftequipment!is played by-

|,

the combined mass transter of dissolved-iron'and cobaltLeompounds. The ji

etf ectiveness of purification systems :is also dependent. on thei total- i

solubility of iron corrosion products,,

4

L

|? Much attsntion has already been devoted to . questions' of. theL " theoretical" determination of the solubility of firon-compounds' in water - '

as a function of the pH of the medium, temperature, and concentration of.' dissolved oxygen or hydrogen [1-7). Onesignificantshortebmingofthese ~I

r

L'

works is the fact that thermodynamic calculations at high temperatureswere carried out using" thermal constants-defined;according _to the method

p of Criss and Cobble. [8). The " principle of' correspondence"Lof Criss andL Cobble is limited to a specific set of chemical' forms of components of the

solution, and also is= valid only atLtemperatures not exceeding 500 K.

In the present vork, on the. basis of- hypotheses -set f orth previously.$

-

[9,10), the solubility of iron corrosion products'in a. heat-transf er .-

agent in-the circuit of a nuclear power plant with boiling vater. reactoris calculated. The greatest attention'is devoted to the solubility of

.

.... c ;

( n }.

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,,; .. >i

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pgnetite as .the primary product; dictating? the behavior of- other iron-

. corrosion ~ products.. ,

The composition of'_ vater-salt solutions was found by the numerical;method of. nonlinear;. optimization of;Gibbs energy of the system components:(11].

Selection and substantiation 'of-initial. data on Lthe basis of ' thermal |

constants under standard conditions,:i~. eiat 298',15.1."and O.1013 HPa;' vere carried out' f or_ two series of values of Gibbs energy AG andL entropyAS of the ,f ormation both?of dif f erent solid' phases and ' of! dissolved;

chemical f orms of.: iron, which were recommended inivorks [1] and (12). The; '|choice of these two works is' based on~ the f act thatihey present the:

. Iullesh inf ornation, although 'it. dif f ers 'significantly. 'If certain data-were absent 'f rom the ref erence (12) they. vere completed 'on the~ basis of

:

the analysis of ' experiments set f orth:in work (1),. coordinating' the data .

with the values of Gibbs energy used in' vork (12)' f or' f ormation of ions of 4

di- and - trivalent iron in' the. state |of a' standard aqueous ~ solution. '

Temperature extrapolation of thermodynamic functions of dissolvedchemical f orms vas carried out using.a previously described method [9]. j

-

I,

p In the heat-transf er agent .of.a: boiling vater reactor, due toi -

dissolution of gasesc above all: oxygen or: hydrogen; at least one otherindependent component vill ~always be present?in~the. system, for. examplethe oxidit:er 0 . Even the most meticulous removal of oxygen from the2 '

. vater without' measured addition of chemical reagents or.the use ofcatalysts (14] is unable .to reduce its ' concentration below 5-10 pg/kg. !The appearance of an additional independent component, according' to the

{e

Gibbs rule.of phases, creates an opportunity for yet another independent !solid phase to form.

Theref ore the System Fe30 -H 0-02 (solution) and the associated4 2

systems Fe2O -H 0-02 ' solution) and Fe(OH)3-H 0-02 (solution) were3 2 2'

subjected to thermodinamic analysis, using two series of input data for>

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the thermal constants of iron compounds. The values of Gibbs energy of I

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f ormation of oxygen in"the state of. a standard aqueous solution at thetemperatures interesting us were'taken from.the reterence.[12). The

results of the calculations shoved- thatethe appearance in the- solution of j~

-

-

an equilibrium concentration of toxygen O'1 pg/kg increases by approx . [.

instely 100 times the' solubility of magnetite as compared'vith the ideal- ;

magnetite-water system. The' nature of|the change in solubility of !

magnetite as a function of temperature obtained!on the basis of ~ the data' !

in-vork (i] agrees with the experimental-research and.the opinion of'the :jauthors of works (2, 14). The. equilibrium compositionLof-solution ~under- -;.

the. intluence 'of 0 changes sharply primarily due' tof the f ormation-in the~'

2

system of the neutral' molecule Fe(OH)o , Moreover, the quantity of the-2 .

latter under 450 K greatly exceeds "its equilibrium contentc upon. disso-;

lution of Fe(OH)3 (crystal') regardless of: whether the calculation was '

carried out on the basis' of, the data Ltrom vork (1_)1or; the ref erence -f 12)..The latter indicates that-within .this range of temperatures yet another ;

1

solid phase should form, above all Fe(OH)3-(crystal), which through '

thermolysis may be transf ormed into dependent 1but more stable and less j,

soluble phases of f erric oxides - goethite Fe00H or hematite Fe2O -3.

Directanalysisof:thesolubility'ofimagnetiteshoved'thatit-is -lI

|. much less than that-observed in experiment.(1) or exceeds itisignificantly D

(12). Thus, none of the initial- thermodynamic constanti, used describe the- :Idata of high tempera * vetexperimental researcli' '

1

The data recommended in.vork (1) vere subjected Lto critical l

i: analysis. Attention should be given above all to'the fact thatLthe- i

- solubility'of magnetite is dictated by'the equilibrium

!

4 + 4H O S Fe(OH)02tre(OH)0 ,9 30 2 3 '

, value of the constant of equilibrium-of.this. reaction is aof the values used for Gibbs' energy.of the formation.ofi

1. , . .e, Fe(OH)02 and Fe(OH)02c The value of the latter is determined-from the, hydrolysis reaction:

1

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j.

-:;-- -

. . . _ _ _ _ _ _ - _ _ _

.-

,. . -

, , ,, .

1

-.

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Fe3+ + 3H2O = Fe(OH)02 + 3H+.~ ,J" :,

.

For this reaction values f orithe' third constant 7 of, hydrolysis pKris are,

_ given as 4.52.(15),.9.38 [16), 13,6 (17), . Invork(ib).itisnotedthat!

the pK of -this reaction should be greater than 12. On _th'e basis of the /4latter ~ recommendation, in-verk (1) the value- of 13,6 is accepted f or pK sei !

The value of LGibbs energy of' the f ormation.of' the ion 1Fe2+ of -86.3

kJ/ mole was obtained by averaging analogousDvalues - (-84,9. [19),-91.2 [20]';-78.9-

( 21) , -90,0 ( 22) , -91. 8 kJ/ mole-[23} ), and dictates the- very lov' solubilityof-magnetite. In reterence (12),aon the~ contrary,|the valuetof Gibbs i

-

energy of f ornation of the. ion of divalent iron in a standard aqueous = [.

solution is -92. 26' kJ/ mole,- and the value-~of pKr13:is taken to be 9. i,' "

. which when other; constants of hydrolysis remain identical leads 1to~

- unjustifiably high values of solubility of magnetite. a,

Relying:on analysis of the| literature _on hydrolysis of compounds of-

3

di- and trivalent iron, and also on.the cyperimental data'of [2,f14-, 24]. on study of the solubility of. magnetite and hematite in water in the

!

presence of oxygen, .We recommend. that MN,7/;. :(Fe2+) b'e taken .to be -90. O-

kJ/ mole, and pgr 3~11.5,. The system of-coordinated values;of thermal'

constants of various chemical f orms of' iron in the: state of;a'atandard.--

aqueous solut' ion that we used -is shovn:in Table 1. Tables:2 and 3'present- :|. the composition of solutions <of. components found.in-equilibrium in the '

O . . .isystems Fe3 4-H20-00 2 and Fe2 3-H 0-0 .,

2 2 '|

l'

L Fig. 1 presents the results of calculation:of the._ solubility of iron !'

in the systems Te304-H20-02 and Fe(OH)3-H20; using our values of1 thermal '

' constants. The resulting solubility curve coincides quant'itatively.With !..

the data from experimental analyses of the solubility of magnetite.in pureHu tp- Water.1

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Fig. 1. Results of computation of: solubility of Liron in systems'Fef04--H 0-02 and Fe(OH)3-H2O using the. values'of:. thermal constants of: solubility.2

.

of-Fe04 used by the suthors.given concentrations;in water: 10.pg/kg1(1),100 gg/kg (2),.1000 pg/kg.-(3).and'Fe(OH)s;L(4)|,. The results'ofiexperi-- jmental analyses of solubility'of magnetite,in-pure water:18. '(14);,0 -

.

'

(2]; e - (24]. 1

1l Thus one may argue thatiunder - 123 K in an. aqueous soluti'on containing'"

~

oxygen, magnetite is unstable' and 1 oxidizes 'first:of' all t'o Fe(OH)3; this- !i

hydroxide'is less soluble and precipitates with' subsequent dehydration and N )the fornation of Fe00H or.Fe20 . When. temperature increases;c the (3

,

| solubility of the -hydroxides increases Over. 423' K magnetite is stable in - '

y tb. medium, but its solubility. decreases as temperature = increases. An- ji

L. inc.aase. in the equilibrium concentration of oxygen in the water f rom 0.1 -.

to 1000 pg/kg.only slightly increases the solubility of magnetite; as-,

| temperature increases this etfect-becomes ever.more negligible. Hematite-'

is stable. at.all. oxygen -concentrations.-

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:f'htble 1. Gibbs energy and entropy of fornation of substances -j4 |!

|Chemical 5/.209, 4Gh,.J/moleatT,1 *

formula J/ mole , K-

298.15 373.15 423.15 523.16 623.15

Feo 59,8 -251,2 -256.1 -259.8 -268,1 >77.3 1

Fe(OH)2 106 -493.5 -502.3 -509.0 -524.1 -541.OFe(OH)3 105 -705.1 -713.V -720.7 -736.2 -753.7 -Fe00H 60.38 -497.8 -503,0 -507,1 --516.5 -527,4Fe2O3 87.4 -742,7- -750,2 ~ 756,2 -770.3 -787.0 |

-

Fe304 146 -1012.6 -1024.9 -1034.5 <1045.9 -1083.0-Fe2+ 107 -90.O ~77.9- -68.6 -46,3 -3.4 !Fe0H+ -46.7 -274.1 -269.1 -265.7 -259.0 -249.6Fe(OH)h 73.7 -457.0 -462.9 -467.2' -476.5 -486.5Te(CH)3 56,3 -619.1 -625,2 -629,1 -637.1 -642.5

..

Fe(OH)2 4 20.0 -773.9 -778.5 -781.O ~783.3 -771.5 i

Fe3+ -201 -16.6 12.1 33.3 84.8 184.5<

Fe0}f2+ -117 -238,7 -226,3= -217.5 -197.1 -162.2Fe(OH)+2 -37.7 -449,1 -444.8- -441.8 -436.0 -427.4 |Fe(OH)03 66.8 -661.5 -666.9 -670.8- -679.4 -688.8 !,

Fe(OH) 4 41.6 -834.5 -839.C ' 942.7 -849.2 -852.9',

H+ 0 0 2. 0 3. 9 9. 8 28.4OH- -10.71 -157.23 -157.07 -156.44 -153.20 148.28

i HO 69.95 -237.18 -243. 07 -2-|7. 66 -258.10 269.982

02, solution 110.9 16.5 6. 9 -0.8 -19.0 -42.5 -

_ - - - -;

./5Thus the tolubility of iron in_the system examined here (at lov and

average values of oxygen concentration) with changing temperature vill bemaximal at approximately 423 K. Below that temperature solubility vill be i

! dictated by Fe(OH)3 (crystal), at higher temperatures by magnetite. 'hise - interpretation logically explains the results _of the experimental analysis

- of solubility of magnetite in desalinired water containing 10 pg 02 in 1 !kg H O [14), the results of' analysis of the solubility of iron corrosion; 2 '

0 '

*

, -

-

'',,

*,

|.

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products in desaliniced veter at a concentration of dissolved oxygen fromunder 10 to 1200 pg in i kg of H 0 (2), and also the increased concen-2 _ _

|tratior of iron in Vater during reactor' outage when passing through the '

temperatute range 180-120' C. Upon contact with metallic iron at the _,

temperature of the heat-transfer agent of the boiling water reactor only (the phase Fe304 is thermodynamica11y. stable. The outer layer of oxide

;

film f orms due to precipitation of iron f rom the water and may includethe phases Fe2 3, Fe00H, Fe(Oll)3 .Upon an increase in the oxygen content |

0.

in the heat-transf er agent in a neutral ~ oxygen-voter mode of the

condensate-feedvater circuit (core) a '

slowing of corrosion 13 observed due to attainment of a certain oxygenconcentration. This slowing is accompanied by a reduction of theproportion of corrosion products carried into the heat-transf er agent(25). Analysis of the redistribution of _ metal (upon its corrosion)-between the oxide film and the heat-transf er egent shows that this processis not rancom and is dictated by the properties of the heat-transfer -

agent,;

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Ttble 2. Solubility and-composition of solutions in system Fe30 -H 0-04 2 2

Chemical Equilibrium Ig are at T, I__

formula concentrationof 02 in H 0, 298.15 373 473 573 6232

#g/kg

OH- 10 7.00 6.16 5.73 5.07 6.291000 6.99 6.16 5.73 5.87 6.29

H+ 10 7 .01 6.16 5.73 5.87 6.291000 7.01 6.16 5.73 - 5.87 6.29

Fe2+ 10 15.23 13.73 12.93 13.02 13.481000 16.57 14.06 13.26 13.35 13.82

Fe0H+ 10 17.52 15.11 13.31 12.22 11.641000 17.86 15.44 13.64 12.55 11.97

Fe(OH)02 -10 20.02 16.13 13.03 11.13 '10.431000 20.35 16.46 13.36 11.46 10.77

Fe(OH) 3 10 26.16 21.57 18.11 16.27 16.141000 36.49 21.90 18.44 16.61 16.38

Fe(OH)2 4 10 33.by 28.27 24.55 23.14 24.331000 33.91 28.60 24.88 23.47 24.56

Fe3+ 10 15.40 16.57~ 18.61 21.'57 24.341000 15.24 16.41 18.44 21.40 24.17

Fe0HP+ 10 10.86 11.37 12.38 13.57 14.251000 10.70 10.20 12,21 13.41 14.09

Fe(OH)+2 10 8.54 8.91 9.66 10.22 10.401000 8.48 8.75 9.49 10.22 10.40

Fe(OH)03 10 5.87 5.97 6.42 7.00 7.311000 5.71 5.00 6.25 6.83 7.14

Fe(OH) 4 10 10.11 9.97 10.45 11 35_ ~ 12. 34.

1000 9.94 9.80- 10.28 11.18 12.17IFe 10 5.07 5.97 6.42 7.00 7.311000 3.71 5.80 6.25 6.83 7.14. Ej

O],

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Table 3. Solubility and composition of solutions in system Fe2 3-H20-020 *

(range of oxygen concentrations 1-1000 pg/kg)- |

Chemical -1g % at T,1: |

!ormula. ,

298.15 373.15 423.15 473.15 523.15 573.15 623.15

OH- 7.003 6.159 5,869 5.734 5.725 5.868 6.829 |H+ 7.003 6.159 5.869 5.734 5.725 5.868 6.289Fe2+ 29.697 29.129 30,529 32.613 34.718 37.527 40.699

'

re0H+ 31.993 30.512 31.408 32.995 31.508 36.728 -38.853Fe(OH)02 34.499 31.531 31.693 32,712 53.816 35.634 37.650Fe(OH)-3 40.648 36.972 36.913 37.792 38.852 40.780 43.630Fe(OH)2-4 40.076 43.672- 43,167 44,229 45.373 47,645 51,447

Fe3+ 21.006 20.796 21.087 21.627 22,199 23,778 26,222 *

Fe0H2+ 16.470 15.587 15.363 15.398 15.531 15.782 16.140Fe(OH)t2 14.158 13.135 12.835' 12.678 12.615 12,595 1.450 -

Te(OH)03 11.196 10.193 9.725 9.437 9.277 9.205 9.193 ,

Fe(OH)-4 15.736 14.192 ~13.724 13.468 13.405 13.558 .14.224IFe 11.496 10.193 9.725 9.137 9.277 9.205 9.193

,

f

Because the processes of corrosion and precipitation in thecondensate-feed circuit take place against a background of a so-called" transitory" concentration of iron, which entered fran previous segmentsof equipment of the nuclear power plant (13), one can propose the f olovingtime sequence of the stages of the influence of oxygen on the water regimeof the CFC, corrosion and precipitation of corrosion products of: steels invater at T < 430 K. During the first stage oxygen interacts with divalentiron (and its hydroxy forms in water found in the composition of~ oxides onthe valls of the equipment) and convert it to the form of trivalent iron,above all Fe (OH)03 During the second stage an increase takes place ~ in

~

ithe concentration of Fe(OH)3 in the water, and above all in the layer near (

the vall (due to counter diffusion of 02 and Fe2+). According to thespecific conditions in the CFC (temperature, flov speed, concentration of" transit" fron and impurities, etc.) the concentration of oxygen necessary:

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<-

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.

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to reach the limit of solubility of Te(OH)3 is reached; its value ranges! rom 20 to 400 pg/kg. .

:,

Upon contact with the surf ace of steel (phases Me3 4, Me:03) |0

dehydration of Te(OH)3 takes place, and in 600-1000 hr the steel surfacebecomes covered with a layer of oxides re00H and Fe2 3 over the magnetite,0

,

which forms, in turn, through crystallization.!r

Together with a shi!t of the metal's potential under the action ofoxygen. this process determines the " protective" concentration of oxygc." ,

During the third stage coagulation and precipitation of re(OH)3, Te00H anc.,

Te2O3 on the surfaces of equipaent-and in. stagnant zones take place,

!

01

4 E'( h- + ne .

tro XWx [M .h~

,400 -

fcoc # i

' ' 40J - ~. b,g,,,,,h*--}|m(I;;px( -fccjm t. . rot.

b'

100,

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rig. 2. Diagram of heat-transfer agent circuit of nuclear powerplant with expanded flow. (a) : KT--turbine condenser; KO--purifi- 1

cation condenser; 1111/41-5--low pressure users; .7 deacrator; sc. --mixing unit; 'TBC--f'uel assemblies; no --bypa ss purifier; /r --separatordrum; 4 0 --point of introduction of oxygen. Change in temperature2

(---) and concentration of 02 upon movement of heat-transfer agentfrom turhine condenser to fuel assemblies of reactor (b): XXX--coain normal modo 0--CO2 upon delivery of oxygen. Change in solubilit'yof ferric oxides upon movement of heat-transfer agent (c) : 1-- '

;

system Po30%~ ~H20-02 (without addition of 02); 2--system Fe20 -H2 0-02,3(with addition of 0 )2 l

,

10

. .

..

. . _ - _ _ _ _ _ _ _ _ _

.-,,

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,

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.iAnalysis of the phase composition of corrosion products f rom water ;

of a nuclear power plant circuit operating in an uncorrected mode [13, '

26] showed the presence of Fe304 phases, in addition to others, along the;

entire circuit. 'lhe introduction of oxygen-in suf ficient quantities . ipermits one to anticipate complete transformation of magnetite into lhepatite. Considering this, Fig. 2 presents a diagram of change inparameters (temperature, concentration of gases) and values calculated in

;this work of the concentration of various f orms of iron compounds that arestable given corresponding parameters along the path of movement of the-heat-transfer agent in.a nuclear power plant with boiling vater reactor.The diagram is executed f or two water-chemical modes of the CFC - aneutral uncorrected mode and a neutral mode with the metered addition

'

| of oxygen at a point beyond condensate purification. Curve i in Fig. 2characterizes the dynamics of change in.the equilibrium concentration of I

tron f or the system Fe3 4-H2 -02 (lov values of oxygen concentration) and'0 0, curve 2 shows the same f or. the system Fe2 3-H20-02-(high values of oxygenO

concentration in the condensate circuit).5

Comparison of curves i and 2 shows that introduction.of oxygen to77

the water of the condensate circuit of 'a nuclear power plant with RDtIK-1000 permits one to anticipate a significant reduction.in the' entrance ofdissolved forms of iron into the. reactor circuit, which reduces the -

buildup of deposits on the surface of: fuel elements and activation ofcorrosion products associated with those deposits. The latter hypothesiscorrelates with the known (27] ef f ect of a reduced rate of growth of thedose arourd primary circuit pipelines:on Japanese nucler.r power plants with',

'

boiling veter reactors upon metered-addition of oxygen to'the condensate-feedvater circuit,

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.

!REFERENCES !

!11. Belyanin V.S. Analyses of the thermodynsmic properties of aqueous

iron compounds. - In: Obzory po teplofizicheskin svoystvan veshchesty |(Surveys of the thermophysical properties of substnces) M Ts). M. : jIVTAN, 1982, No. 4 (36), p. 109-166.

2. Martynova 0. I. , Samoylov Yu.F. . Petrova T. I. . :1:hsritonova N.L.

Solubility of corrosion products of unalloyed steel in oxygen--containing aqueous solutions at high temperatures. - Teplofizikavysokikh temperatur, 1983, V. 21, No; 5, p. 913-918,

3. MacDonald D., Shierman G., Butter P. The thermodynamic of metal-vatersystems at elevated temperatures. Part 2. WNRE AECL-4137, 1972.

4. Tremaine P., Le Blane L. The solubility of magnetite and hydrolysisand oxidation of Fe2+ in water to 300 C. - J. Solut. Chen. ,1980, v.

!

22, p. 415-442.5. Belyanin V.S., 1otenkov V.N. Thermodynamic analysis of stability and |

. complex compounds of iron in an aqueous heat-tranafer agent. -Teploenergetika, 1979, No. 9, p. 59-61,

t6. Manet V.A. Belyanin V.S. Computer calculation ofichemical composition i

of aqueous heat-trans!er agents and processes of f ornation ofdeposits. - Ibid, 1985, No. 10, p. 38-41. I

e7. Spravochnik fizicheskikh konstant gornykh porod [ Manual _of physical| constants of rocks). - Trans. from Eng. Ed. S.P, Clark. M.: Mir,

1969.

8. Criss G., Cobble I. The . thermodynamic properties of high temperature,

; aqueous solutions. IV. Entropies of ions up to 200* C and the1

correspondence principles. - J. Amer. Chem. Soc., 1964, V. 86. No. 24,l p. 5385-5389.

9. Zarenbo V.I., Puchkov L.V. Standard Gibbs values of formation of ions; and ion associates in an aqueous solution given high state variables.L - In: Obzory po teplofizicheskim svoystvan veshchesty (TFTs) (Surveys

of thermophy<ical properties of substances). M. : IVTAN, 1984. No. 2(46). '

.

10. Sedov V.M. , Puchkov L.V , Yritskiy V.G. , Zarembo V.N. Physicochemical;

bases of modeling of the couposition of an aqueous heat-transf er agent

ic !

.

|-

.,

.\.

!.

of a nuclear power plant. - Atonnaya energiya, 1985, V. 59, Iss. 6, p..

395-398. 1

11. Karpov I.K., 1:iselev A.I., Letnikov l'.A. Modelirovaniye prirodnogo I

mineraloobrazovaniya na EYM (Computer modeling of natural minerali

: Iornation). - M.: Nedra, 1976.12. Naumov G.B., Rythenko V.N., Khodakovskiy I.L. Spravochnik

termodinamicheskikh velichin (Handbook of thermodynamic quantities). -M.; Atomi:dat, 1971,

13. Moskvin L.N. , Yefinov A. A. , Sosnovskaya Ye.Y, et al. The use of NGR-spectroscopy to determine the phase composition of fine-dispersioncorrosion products of reactor materials.in an aqueous heat-transter !

agent. - Atonnaya energiya, 1981, V Si, Iss. 6, p. 383-385.-

14. Bohnsack G., Bursik A. Messungen sur Magnetitloslichkeit in reinem |

Wasser. - IAPS Report, 1983;15. Gaver K. , Voontner L. The solubility of ferrous hydroxide and ferric i

hydroxide in acidic and basic medie at 25' .:. - J. Phys, Chem., 1956, '

V. 60, No. 11,:p. 1569-1571,

16. Mattoo B.N. Description of equilibria in fystemr. of ferric-ferrocompound'a based on new processing of.the r eorinental data of 0.N.

t Lapteva. - Zhurn, prikl. khimiyi,1960, V.. 33, No. 9, p. 2015-2020.17. Byrne R. , Kexter D. Solubility r,t' hydrous ferric oxide and iron

speciation in seavater. - Marine Chem.. 1976,1 V, 4, No. 3, p. 255-274.t

.

18. Baes C. , Mester R. The.hyarolysis of cations. New York: John Vileyand Sons, Inc., 1976.

,

19. Randall M., Frandsen M. The standard electrode _ potential of iron andthe activity coef ficient of f errous chloride; - J. Amer. Chem. Soc. ,1932, v. 59, No. 1, p. 47-54,

20. Larson I. , Cerutti P. , Garber H. , Hepler L. Electrode metals andthermodynamic data f or aqueous ions. Copper, ::inc, cadmim, iron,

[ cobalt and nickel. - J. Phys. Chem., 1968, v. 72,~No. 9, p. 2902-2907. I21. Patrick V., Thompson V. Standad electrode potential of. iron-ferrous-

! ion couple at 25' C. - J. Amer. Chem.-Soc,, 1953, V 75, p. 1184-1187. :L 22. Herlen T. Electrochemical behaviour of iron. - Acta Chem. Scand.,

1960, v. 14, No. 7, p. 1533-1554.i

i

13

..

s

,m,

m'

.,,

*.

*.

.

23. Sweeton T., Baes C, The solubility of magnetite and hydrolysis of -f ercoul ion in aqueove solutions at elevated temperatures. - J. -Chem.Thermodyn., 1970, v. 2, No. 4, p. 479-500.

24. Styryakovich M.A., Martynova 0.I., Kobyakov I.F. et al. - Solubilityof magnetite in high temperature boiling veter. - Teploenergetit s,1971, No. 7, p. 82-84.

25. Et:itskiy V.G., Korolev A.S,, Berezina I.G., Sof'in H.V. Removal ofcorrosion products f rom the surf ace of steel in the aqdcous heat-transfer agent of a nuclear power plant. - Atonnaya energiya, 1985, V.59, iss. 6, p. 401-403.

26. Yefinov A.A., Moskvin L.N., Bredikhin V.D. Analysis of corrosion*

products in the circulation circuit of a nuclear power. plant withRBMK. - Teploenergetika, 1984, No. 11, p. 8-10.

27. Misha I. Vater chemistry in the Japanese light water reactors. -'In: :

Spec. Meet. on Influence of' Power Reactor Water Chemistry of Fuel,

Cladding Reliablity, vienna: IAEA, 1982, IWGTPT-11, p. 210-221..

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| AGENT OF A NUCLEAR POWER PLANT WITil BOILINGSOLUBILITY OF MAGNETITE IN THE !! EAT TRANSFER '

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WATER REACTOR ***"*''""''0"'6"'D Iusi.

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The solubility of iron corrosion products in a heattransfer agent in the circuit of a nuclear nower plantwith boiling water reactor is calcula %d. Greatattention is given to the solubility of magnetiteas the primary product dictating the behavior of otheriron corrosion products. It was found that therewere Fe 03 4 phases along the entiro circuit. It

was also concluded that introduction of oxygen to thewater of the condensato circuit leads to a significantreduction in the dissolved forms of iron in the reactorcircuit, which reduces the buildup of deposits on thesurface of fuel olomonts and activation of corrosionproducts associated with these deposits.

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& NRC Translat$n- AllI :i

I'Lh uage of Foreign Document: RUSSI^N

Tran'tdeted Title of Document: SOLUBILITY OF MAGNETITE IN T!!E !! EAT TRANSTER'N AGENT OF A NUCLEAR POWER PLANT WIT!! !

BOILING WATER REACTOR :

;

Untran ted Title: RASTVORIMOST' MAGNETITA V TEPLONOSITELEAES S KIPYAS!!C! LIM REAKTOROM

-

.

\ -

Author (s): W I. ZAREMBO, V.G. KRITSKIY,*

A. .SLOBODOV, L.V. PUCIIKOV.

Translated Name and Address KURClATOV-INSTITUTE FOR ATOMIC ENERGYof Corporate Author: MOSCO) USSR

Untranslated Name and Addressof Corporate Author:

i.

Date of Original Foreign Document: (NOT GIVEN)

| Foreign Document ID Number (s): 10-5

Number of Pages in Translation: 14 -

Date Translated for NRC: MAY 1989

NRC Requester / Office: EDWARD SH0 MAKER, GPA*

! Transle;ed by: ScITRANi Name and 1482 EAST VALLEY ROAD

Address SANTA BARBARA CA 93150 ,

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.

/

Solubility of magnetite in the heat tranaf er agent of a nuclear power/2plant with boiling vater reactor

Zarembo V. I. , l'ritskiy V.G. , 31obodov A. A. . Puchkov L.V.|

Certain demanis are made.on the organi::ation of the water-chchicalmode of nuclear power plants: the aggressiveness of the heat-transteragent must be minimal with respect to the structural caterials ofcircuits, contaminants must be prevented f rom entering the r*dioactivereactor core, and deposits must be prevented f rom overgrowing the core and-heat exchange equipment.

The use of water of a high degree of purity as the heat-transter-agent of a boiling water reactor has eliminated the possibility of-formation of salt deposits. In this case corrosion products (CP) of /3structural materials have become the main " scale f orners": ' oxides of iron,chromium, manganese, nickel, cobalt and their hydroxides. A decisive rolein the buildup of radioactivity on the surface of equipment is played bythe combined mass transter of dissolved iron and cobalt compounds. Theetiectiveness of purificetion systems is also dependent.on the totalsolubility of iron corros15n products.

| Much attention has already been devoted to'. questions of the" theoretical" determination of the solubility of-iron compounds in wateras a function of the pH of the medium, temperature, ~ and concentration ofdissolved oxygen or hydrogen (1-7). One significant shortcoming of theseworks is the fact that thermodynamic calculations at high temperaturesvere carried out using thermal constants defined according to the method;

i of Criss and Cobble (8). The ' principle of conespondence" of Criss and| Cobble is limited to'a spec 1*.1c set of cher.ical forms of components or the

solution, and also is valid only at temparatures not exceeding 500 E.

;

In the present work, on the bests of hypotheses set forth previously[9,10), the solubility of iron corrosion products in a heat-transf eragent in the circuit of a nuclear power plant with bolling water reactoris calculated. The greatest attention is devoted to the solubility of

f

.

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..

.-

.

fpgnetite as the primary product dictating the behavior of other ironcorrosion products.

!The composition of water-salt soluticns was found by the numerical

,

method of nonlinear optini::ation ot Gibbs energy of the system components !(11).

!

!

Selection and substantiation of initial data en the bssis of therun1 i

constants under standard conditions, i. e. , at 298.15 E ard 0.1013 tPa, >

vere carried out for two series of values of Gibbs energy 4G and entropyAS of the fornation both of different solid phases and of dissolvedchemical !orms of iron, which were recommerded in works (il and (12). Thechotee of these two works is based on the f act that they present thefullest intornation, although it ditfers signi!icantly. If certain data

,

1

were absent irom the reterence (12) they were completed on the basis ofthe analysis of experiments set iorth in work (i), coordinating the datawith the values of Gibbs energy used in work (12) !or fornation of ions ofdi- and trivalent iron in the state of a standard aqueous solution.

Temperature extrapolation of thermodynamic functions of dissolved;

chemical f orms was carried out using a previously described method (9).

In the heat-trans!er agent of a boiling vater reactor, due todissolution of gases, above all oxygen or hydrogen, at least one other i

independent component will always be present in the system, f or examplethe oxidizer 0 . Even the most meticulous removal of oxygen from the2

water without measured tddition of chemical reagents or the use ofcatalysts (14) is unable to reduce its concentration below 5-10 pg/kg.

4

The appearance of an additio0a1 independent component, according to theGibbs rule of phases, creates an opportunity f or yet another indeperdent

4solid phase to fora.

Theretore the system Te304-H20-02 (solution) and the associatedsystems re2O -H20-02 (solution) and Fe(OH)3-H 0-02 (solution) were

;3 2

subjected to thermodynamic analysis, using two series of input data for,

the thermal constants of iron compounds. The values of Gibbs energy of '

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- . - - -. - _ _ _ _ _ _ . - - _ _ _ - - - -

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f ornation of oxygen in the state of a standard aqueous solution at thetemperatures interesting us were taken f rom the reterence (12). The

results of the calculations showed that the appearance in the solution ofan equilibrium concentration of oxygen 0.1 pg/kg increases by approx-instely 100 times the solubility of magnetite as compared with the idealmognetite-vater system. The nature of the change in solubility ofmagnetite as a function of temperature obtained on the basir of the datain work (1) agrees with the experimental research.end the. opinion of theauthors of votAs (2,14). The equilibrium composition of solution un?.erthe influence of 02 changes sharply primarily due to.the formation irithesystem of the neutral molecule Fe(OH)02 Moreover, the quantity of thelatter under 450 K greatly exceeds its equilibrium content upon dia:lo-lution of Te(OH)3 (crystal) regardless of whether the calculation wes

carried out on the basis of the data f rom work (1) or the ref erence (12).The latter indicates that within this range of temperatures yet anothersolid phase should f orm, above all Fe(OH)3 (crystal), which throughthermolysis may be transf ormed into dependent, but more stable and lesssoluble phases of f erric oxides - goethite Fe00H or hematite Fe2O .3

Direct analysis of the solubility of magnetite showed that it ismuch less than that observed in experiment (1) or exceeds it significantly(12). Thus, none of the initial thermodynamic constants.used describe thedata of high temperature experimental research.

The data recommended in work (1) were subjected to criticalanalysis. Attention should be given above all to the f act that the

| - solubility of magnetite is dictated by the equilibrium

Fe304 + (H2O # Fe(OH)0 +Fe(OH)032

The value of the constant-of equilibrium of this reaction is afunction of the values used for Gibbs energy of the formation ofmagnetite, Fe(OH)02 and Fe(OH)0 , The.value of the:latter is determined2

from the hydrolysis reaction:

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9

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-- . .. -- -. .

'i

.

Te3+ + 3H2O = Te(OH)02 + 3H+.:

for this reaction values f or the third constant of hydrolysis pgr13 6te '

given as 4.52 (15), 9.38 [16), 13.6 (17). In vork [18). it is noted thet lthe pK of this reaction thould be greater than 12, On the basis of the /4latter recommendation, in vork (1) the value of 13.6 is accepted f or pl'13 !The value of Gibbs energy of the f ormstion of the ion Fe2+ of -36. 3 +

,

kJ/ mole v6s obtained by averaging aralogous values (-84. 9 [19),-91.2 [20),-78.9[ 21), -90. 0 ( 22), -91. 8 kJ/ mole [23)) snd dictates the very lov lolubilityof n.agnetite. In ref erence (12', on the contrary, the value of Gibbs

i

energy of f ornation of the ion of divalent iron in a standard aqueous ;

solution is -92,26 kJ/ mole, and the value of pgris is taken to be 9.1, '

which when other constants of hydrolysis remain identical leads tounjustifiably high values of solubility of magnetite,

i

W

Relying on analysis of the literature.on hydrolysis of compounds ofdi- and trivalent iron, and also on the experimental data of (2, 14, 24)on study of the solubility of magnetite and hematite in vater in the

s

presence of oxygen, we recommend that Mt.'1.','f, (Fe2+) be'tagen to be -90.0kJ/ mole, and pKris 11.5. The system of coordinated values of thermal

constants of various chemical !orms of iron in the state of a standardaqueous solution that we used is shown in Table 1. Tables 2 and 3 present .

the composition of solutions of components found in equilibtium in the,+

'

systems Te3 4-H 0-00 2 2 and Fe2 3-H20-0 .0 2

Fig. 1 presents the results of calculation of the solubility of iron|in the systems Te304-H 0-02 and Te(OH)3-H O using our values of thermal|

2 2

constants. 1he resulting solubility curve coincides quantitatively with]

the data from experimental analyses of the solubility of magnetite in pure ivater. I

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Fig. 1. Results of computation of solubility of 1ron in systems Te3 4-0,

H 0-02 and Fe(OH)3-H O using the values of thermal constants of solubility2 2 '

of Te04 used by the authors given concentrations in water: 10 #g/kg (1),100 pg/kg (2), 1000 gg/kg (3) and Te(OH)3 (4). The results of experi- ;mental analyses of solubility of magnetite in pure water: e - (14); O -

#

(2); 9 - (24).1

k

Thus one may argue that under 423 K in an aqueous solution containing;'

oxwen, magnetite is unstable and oxidizes first of all to Te(OH)3; this {

hydroxide is less soluble and precipitates with subsequent dehydration and O| the f ornation of Te00H or re2O , When temperature increases, the3

isolubility of the hydroxides increases. Over 423 K magnetite is stable inthis medium, but its solubility decreases as temperature increases. An

increase in the equilibrium concentration of oxygen in the water from O.1to 1000 pg/kg only slightly increases the solubility of magnetite; astemperature increases this_ ef f ect becomes ever more negligible. Hematiteis stable at all oxygen concentrations. '

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Table 1. Gibbs energy and entropy of formation of substancesj4

)

Sf . m ,oChemical 600 , kJ/ mole at T, Ks

formula J/ mole K

298.15 373.15 423.15. 523.16 623.15

Fe0 59.8 -251.2 -256,1 -259.8 -268.1 '-277.3Fe(OH)2 106 -493.5 -502.3 -509.0- -524,1 -541.O !Fe(OH)3 105 -705.1 -713.9 -720.7 -736.2 -753.7Fe00H 60.38 -497.8 -503.0 -507.1 -516.5 -527.4Fe203 87.4 -742.7 -750.2 -756.2 -770.3 -787.0Fe3 4 146 -1012.6 -1024.9 -1034.5 -1045.9 -lu83.00

Fe2+ 107 90,o 77.9 -68.6 -46,3 -3.4Fe0H+ -46.7 -274.1 -269.1 -265.7 -259.0 -249.6Fe(OH)02 73.7 -457.0 -462.9 -467.2 -476.5 -486.5Fe(OH)3 56.3 -619.1 -625.2 -629.1 -637.1 -642.5Fe(OH)2 4 20,0 -773.9 -778.5 -781.0 -783.3 -771.5Fe3+ -281 -16.6 12.1 33.3 84.8 184.5Fe0H2+ -117 -238.7 -226.3 -217.5 -197.1 -162.2Fe(OH)+2 -37.7 -449,1 -444.8 -441.8 -436.0 -427.4Fe(OH)os 66.8 -661.5 -666.9 -670.8 -679,4 -688.8,

Fe(OH) 4 41.6 -834.5 -839.5 -842.7 -849.2 -852.9H+ 0 0 2. 0 3. 9 9. 8 28.4OH- -10.71 -157.23 -157.07 -156.44 -153.20 148.28H2O 69.95 -237.18 -243.07 -247.66 -258.10 269.980 , sole. tion 110.9 16,5 6. 9 -0. B -19.0 -42,52

|.

/5Thus the solubility of iron in the system examined here (at lov and

average values of oxygen concentration) with changing temperature vill bemaximal at approximately 423 K. Below that temperature solubility vill bedictated by Fe(OH)3-(crystal), at higher temperatures by magnetite. Thisinterpretation logically explains the results of the experimental analysisof solubility of bagnetite in desalinized water containing 10 pg 02 in ikg H 0 (14), the results of analysis of the solubility of iron corrosion2

0.,

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.-

',

;

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1products in desalinized water at a concentration of dissolved oxygen f remunder 10 to 1200 pg in i kg et H:0 (2) and also the_ increased concen-tration of iron in Vater during resctor outage when passing through thetemperature range 160-120+ C. Upon contact with metallic iron at thetemperature of the heat-transf er agent of the boiling veter reactor only I

the phase re2 4 is thermodynsnically stable. The outer layer of oxide0

film f orms due to precipitstion of iron f rom the water and may include '

the phaser. Fe2 3, Te00H, fe(OH)3 tJpon an increase in the oxy;en contentO

.n the heet-transfer agent in a neutval oxygen-vater mode of the '

condensate-feedvater circuit (core) 4

sloving of corrosion is observed due 10 attainment of a certain oxygen-]concentration. This slowing is accompanied by a reduction of the

proportion of corrosion products carried into the heat-transf er agent[25). Analysis of the redistribution of metal (upon its corrosion) I,

between the oxide film and the heat-transfer agent _ shows that this processis not randon and is dictated by the properties of the heat-transfer

;agent. '

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Table 2. Solubility and composition of solutions.in' system re3 4-H 0 0: f0 3r

Chemical Equilibrium '1g tre at T,1;i

fformula concentration

of 02 in H 0, 298.15 373 473 573 6232

]|pg/kg,

;.

OH- 10 7.00 6.16 5.73 5.87' 6 291000 6.99 6.16 5.73 5,87' 6.29

H+ 10 7 .01 6.16 5,73- 5.87 6.29 i

1000 7.01 6.16 5.73 5.87 6.29 i

fe2+ 10 15.23 13.73 12.93 13.02 13.481000 16.57 14.06 13.26 13,35 13.82

Fe0H+ 10 17.52 15.11 13.31 12.22 11.64 ;

1000 17.86 15.44 13.64 12.55 11.97 [re(OH)o2 10 20.02 16.13 13.03 11.13 10.43

1000 20.35 ~16.46 13,36 11.46 10.77Fe(OH) 3 10 26.16 21.57 18.11 16,27 16.14

,

1000 26.49 21.90 18.44- 16.61- 16.38Fe(OH)2 4 10 33.59 28.27 24.55 23.14 24.33

1000 33.91 28.60 24.88 23.47 24.561

Te3+ 10 15,40 16.57 18.61 21.57 24.34 i1000 15,24' 16.41 18.44 21.40 24.17 i

ie0H2+ 10 10.86 11,37 12.38- 13.57 14.251000 10.70 10.20 12.21 13.41 14.09

Fe(OH)+2 10 8.54 8,91 9.66 10,22 10.401000 8.48 8.75 9.49 10.22 10.40

Fe(OH)03 10 5.87 5.97 ~ 6'. 4 2 7.00 .7.311000 5.71 5.80 6.25 6.83 7.14

Te(OH) 4 10 10.11 9.97 10.45 11.35 12.341000 9.94 9.80 10.28 11.18 12.17

2Fe 10 5.87 5.97 6.42 7.00 7.31.

'

1000 5.71 5.80 6.25 6.83 7.14

|

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Table 3. Solubility and composition of solutions in systen Fe20 -H 0-023 2(range of oxygen concentrations 1-1000 pg/):g) }

Chemical .lg mr, at T,1: )formula I

298.15 373.15 423.15 473 15 523.15 573.15 623,15,

OH- 7.003 6.159 5.869 5.734 5,725 5.868 6. 6|;9 iH+ 7.003 6.159 5.S69 5,734 5,725 5.868 6.289'Fe2+ 29.697 29.129 30.529 32.613 34.718 37.527 40.699Fe0H+ 31.993 30,512 31.408 32.995 34.508 ,36.728 38.853''Fe(OH)02 34.499 31.531 31.693 32.712 33.816 35.634 37.650Fe(OH)-3 40.648 36.972 36.913 37.792 38,852 40.780 43,630 |

Fe(OH)2-4 40.076 43.672 43.167 44.229 45.373 47.645 51.447 i

Fe3+ 21.006 20.796 21.087 21.627 22.499 23.778 26.222Fe0H2+ 16,470 15.587 15,363 15.398 15:431 15.782 16.140 :Fe(OH)+2 14,158 13.135 12.835 12.678 12,615 12.595 1.450 -

Fe(OH)03 11.496 10.193 9.725 9.437 9.277- 9.205 9.193'

Fe(OH)-4 15.736 14.192 13.724 13,468 13.405. 13.558 14,224EFe 11.496 10.193 9.725 9.437 9.277 9.205 9.193

'

:Because the processes of corrosion and precipitation in the '

condensate-f eed circuit take place against a background of a so-called" transitory" concentration of iron, which entered frca previous segments;

of equipment of the nuclear power plent (13), one can propose the f olovingtime sequence of the stages of the influence of oxygen on the water regime

. of the CFC corrosion and precipitation of corrosion products Of steels in,

water at "/ < 430 K. During the first stage oxygen interacts with divalenti. iron (am its hydroxy iorms in water f ound in the composition of oxides on >

'

the valls of the equipment) and convert it to the f orm of trivalent iron,above all Fe (OH)03 During the second stage an. increase takes place in,

'

the concentration of Te(OH)3 in the water, and above all in the layer intthe vall (due to counter ditfusion of 02 and Fe2+). According to thespecific conditions in the.CFC (temperature, flow speed, concentration of" transit" iron and impurities, etc. ) the concentration of oxygen necessary

9

.

4

-+ _ _ . , . _ . . . _ - - - !

. - _ . -

,

'e

f

.

',

to reach the limit of solubility of Fe(OH)3 is reached; its value ranges '-

from 20 to 400 pg/kg.t

Upon contact with the surf ace of steel .(phases He3 4, He0 )0 3

dehydrat20n of Fe(OH)3 takes place, and in 600-1000 hr the steel surface :

becomes covered with a layer of oxides fe00H and fe2 3 over the magnetite,0

which ' ras, in turn, through crystallization.;,

Together with a shif t of the metal's potential under the action of ,

oxygen, this process determines the " protective" concentration of oxygen.During the third stage coagulation and precipitation of Te(OH)3, Te00H and i

Fe2 3 on the surf aces of equipment and in- stagnant zones take place.O

.

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rig. 2. Diagram of heat-transfer agent circuit of nuclear powerplant with expanded flow (a): KT--turbine condenser;-KO--purifi- )cation condenser; illitt 1-5--low pressure users; il deaeratort.rc --mixing unit; TBC--f' el assemblies; /M---bypass purifier; I;c --separt. torudrum; 4 0 --point of introduction of oxygen. Change in temperatt.ro !

2

(---) and concentra: ion of 02 upon movanent of heat-transfer agentfrom turbine condenser to fuel assemblies of reactor (b): XXX- coa J

,

in normal mode: 6--CO2 upon delivery.of oxygen. Change in solubilityof ferric oxides upon movement of heat-transfer agent (c) : 1--system Pe305- H20-02 (without addition of: 02 ); 2--system Fe2 0 H 0-02(with addition of 02) 3 2

;

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Analysis of the phase compo'sition of corrosion products f rom vater i

of a nuclear power plant circuit operating in an uncorrected node (13, I

26] shoved the presence of re3 4. phases, in addition to others, along the f0

entire circuit. The introduction of oxygen in suf ficient quantitie '

permits one to anticipate complete transf ormation of magnetite intohepatite. Considering this, fig, 2 presents a diagram of change in-parameters (temperature, concentration of gases) and values calculated inthis work of the concentration of various f orms of- 1ron compounds that arestable given corresponding parameters along the path of movement of thr,heat-transfer agent in a nuclear power plant with boiling. water reactor,The diagram is executed f or two veter-chemical modes 'of the CFC - aneutral uncorrected mode and a neutral mode with'the metered additionof oxygen at a point beyond condensate purification. Curve i in Fig. 2characterizes the dynamics of change in the equilibrium concentration ofiron f or the system Fe3 4-H20-02 (lov values of oxygen concentration) and0 *

curve 2 shows the same f or the systen Te203-H20-02'(high values of oxygen

concentration in the condensate circuit).,

.

Comparison of curves i and 2 shows that introduction of oxygen to f7the water of the condensate circuit of a nuclear power plant with RBMK-1000 cermits one to anticipate a significant reduction in the entrance ofdissolved f orms of iron into the reactor circuit, which reduces thebuildup of copccits on the surf ace of fuel' elements and activation of-

| corrosion products associated with those deposits, The latter hypothesis -

! correlates with the known (27) ef f ect of a reduced rate of growth of thedose around primary circuit pipelines on Japanese nuclear pcner plants withboiling water reactors upon metered addition of oxygen to the condensate- '

feedwater circuit.,

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REFERENCES

i

1. Belyanin V.S. Anslyses of the thermodynttic propertie: of' aquecu:-iron compounds. - In: Obr.ory po teplofilicheskim svoystvan veshchesty(Surveys of the thermophysical prepertit s of substnces] (TFTs). H.IYTAN, 1982. No. 4 (36), p. 109-166.

2 Martynova 0. I. . Samoylov Yu.F . Petrova T. I. ,1.'hstitonova N.L.t

Solubility of corrosion products of uns11oyed steel in oxygen-containing aqueous solutions at high temperatures. - Teplofiziksvysokikh temperatur, 1983,'V. 21, No. 5, p. 913-918.

3. MacDonald D., Shierman G., Butter P. The thermodynamic of metal-vatersystems at elevated temperatures. Part 2. VNRE AECL-4137, 1972.

4. Tremaine P., Le Blane L. The solubility of magnetite and hydrolysisand oxidation of Te2+ in water to 300 C - J. Solut. Chem. , 1980, v.22, p. 415-442,

5. Belyanin V.S., Kotenkov V.N. Thermodynamic analysis of stability and'

. complex compounds of' iron in an aqueous heat-transf er egent. -Teploenergetika, 1979, No. 9, p. 59-61.

6. Hamet V.A.. Belyanin V.S. Computer calculation of chemical compositionof aqueous heat-transter agents and processes of f ornation ofdeposits. - Ibid,1985, No.10, p. 38-41.

7. Spravochnik fizicheskikh konstant gornykh porod [Hanual of physical!

constants of rocks). - Trans. from Eng. Ed. S. P. Clark. M. : Hir,1969.

i

8. Criss 0 , Cobble I. The thermodynamic properties of high temperatureaqueous solutions. IV. Entropies of ions up to 200* C and thecorrespondence principles. - J. Amer. Chem. Soc., 1964, V. 86, No. 24,p; 5385-5380

9. Zarenbo V.".., Puchkov L.V. Standard Gibbs values of formation of ionsand ion associates in an aqueous solution given high state variables.- In: Obzory po teplofizicheskin svoystvan veshchesty (TTTs) (Surveysof thermophysical properties of substances). M. : IVTAN, 1984. No. 2!(46).

10. Sedov V.M. , Puchkov L. V. , Kritskiy V.G. ,' Zarenbo V.N. Physicochemicalbases of modeling of the composition of an aqueous heat-transter agent

f2

!-

,

m.

_. -. . . . _ _ - _ _ _ _ _ _ _ - . . - _ - _ _ - _ _ _ _ _ _ - _ _ _

4

.

of a nuclear power plant. - Atonnaya energiya,1985, V. 59. Iss. 6, p.395-398.

11. Karpov I.K., Kiselev A.-I., Letnikov F.A. M' 311roveniye prirodnogo,

mineraloobra:ovaniya na EVM (Computer mod jing of natural. mineralformstion). - M. Nedra, 1976.

12. Naumov G.B., Ry:henko V.N.. Ehodakovskiy I.L. Spravochnik

termodinamicheskikh velichin (Handbook of thermodynamic quantitlesl' -M.; Atomi:dat, 1971.

13. Moskvin L.N. , Yefinov A. A. , Sosnovskaya Ye.V. et al. The use of NGp-

spectroscopy to determine the phase composition of fine-dispersicncorrosion products of reactor materials in an aqueous heat-transf er.

agent. - Atonnaya energiya,1981 V. Si, Iss.16, p. 383-385.-14. Bohnsack G., Bursik A. Messungen zur Magnetitlos11chkeit in reinem

Wasser. - IAPS Report, 1981,15. Gaver K., Voontner L. The solubility of ferrous hydroxide and. ferric

hydroxide in acidic and basic media at 25' C. - J. Phys, Chem..,1956,V. 60, No. 11, p. 1569-1571.

16. Mattoo B.N. Description of equilibria in systems of f erric-f errocompounds based on new processing of the experimental data of 0.N.Lapteva. - Zhurn. prikl. khimiyi, 1960, V. 33, No. 9, p. 2015-2020.

17. Byrne R., Kexter D. Solubility of hydrous ferric oxide and ironspeciation in seawater. - Marine Chem., 1976, V. 4,. No. 3, p. 255-274.

18. Baes C., Mester R. The hydrolysis of cations. New York: John Wileyand Sons, Inc., 1976.

19. Randall M., Frandsen M. The standard electrode potential of iron andthe activity coetticient of f errous chloride. - J. ; Amer. Chem. Soc. ,1932, v. 59, No. 1.-p. 47-54.

20. Larson I., Cerutti P., Garber H., Hepler L. Electrode metals and-thermodynamic data f or aqueous ions. Copper, ine, cadmium, iron,cobalt and nickel. - J. Phys. Che's., 1968, v. 72, No. 9, p. 2902-2907.

21. Patrick V., Thompson V. Standad electrode potential of iron-ferrousion couple at 25' C. - J. Amer. Chem. Soc. ,1953, V. 75, p.1184-1187.

22. Herlen T. Electrochemical behaviour of iron. - Acta Chem. Scand.,1960, y 14, No. 7, p. 1533-1551.

13

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.

. -

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!!.

,

23. Sweeton F,, Baes C. The solubility of magnetite and hydrolysis cff ercoul ion in aqueous soluttens at elevated temperatures. - J. Chem.Thermodyn. ,.1970, v. 2. No. 4, p. 479-500.

24. Styryakovich M.A., Martynova 0.I., Ecbyakov I.T. et al. - Solubilityof magnetite in high temperature boiling veter. - Teploenergetika,

4

1971, No. 7. p. 62-04. jI25. Eritskiy V.G. . Korolev A. S. . Bere:ina I.G. . Sof'in M.V. Removal of

corrosion products f rom the surf ace.of steel in the aqueous heat-,

transfer agent of a nuclear power plant. - Atonnaya energiya, 1985, V,59, iss. 6, p. 401-403. !

26. Yefinov- A. A. , Moskvin L.N. , Bredikhin V.D. Analysis of corrosion !

products in the circulation circuit of a nuclear power plant withRBMK. Teploenergetika, 1984, No. 11, p. 8-10,

27. Hisha I. Vater chemistry in the Japanese. light water reactors. - In:Spec. Meet. on Influence of Power Reactor Water Chemistry of FuelCladding Reliablity. Vienna: IAEA, 1982, IWGFPT-11, p. 210-221. t

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g SOLUB1LITY OF MAGNETITE IN Tile !! EAT' TRANSFERg AGENT OF A NUCLEAR POWER. PLANT WITli BOILINGs WATER REACTOR * o i t * o'ii cou,6 n i t

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TRANSLATION

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The solubility of iron corrosion products in a heat itransfer agent in the circuit of a nuclear power plantwith boiling water reactor is calculated. Great-attention is given to the solubility of magnetiteas the primary product dictating the behavior of otheriron corrosion products. It was found that therewere Fe 03 4 phases along the entire circuit. It >

was also concluded that introduction of oxygen to the;

I water of the condensate circuit leads to a significant'i reduction in the dissolved forms'of iron in the reactor| circuit,.which reduces the buildup of deposits on the

sur. face of fuel elements and activation of corrosionproducts associated with these deposits.

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