Research and Development of Processing and Disposal of
Solid Waste (Examination of Evaluation Technology for
Integrity of Container during Storage of Highly Radioactive

Solid Waste)
PROJECT OF DECOMMISSIONING AND CONTAMINATED WATERMANAGEMENT IN THE FY2020-2021 SUPPLEMENTARY BUDGETProject Main Goals(i)

Accumulation and studying in detail information related to the KURION/SARRY adsorption
towers design features, operating history and results of preliminary investigations [see theslides: 3,4];(ii) Development of corrosion occurrence review report based on Russian Side experience [see theslide: 5];(iii) Implementation of adsorption towers ranking (related to the potential corrosion types,
intensity, etc.) based on the accumulated data analysis;(iv) Research Program Development for subsequent implementation of Corrosion experiments [seethe slides: 6 - 12];(v) Model samples manufacturing [see the slides: 11-12];(vi) Preparation and implementation of Corrosion experiments (in accordance with the Research
Program) [see the slides: 13 - 50];(vii) Prediction Model development to predict possible development of the selected corrosion
processes under the conditions of the 1F site for all of the types of KURION/SARRY adsorption
towers [see the slides: 51 - 62];
(viii) Development of a forecast (using the Prediction Model) to describe the possible developmentof corrosion processes (under the storage conditions) for 50-year storage period [see the slides:
60,61];(ix) Development of Countermeasures set that can reduce the negative corrosion influence under
the real storage conditions of the KURION/SARRY adsorption towers [see the slide: 63];
The main goal of the Project is to develop a Prediction Model for assessment of occurrence of Corrosion
processes that can affect the KURION/SARRY adsorption towers integrity during their 50-year storage.2

Results of preliminary Data accumulation and study (related to the
KURION/SARRY design features as well as storage conditions) (1/2)
Design conditions and storage conditions related to the KURION/SARRY adsorption towers:
Storage conditions:- [Cl-] ~ 10 ppm;
- T ~ 20 ˚C.

Temporary storage of the KURION
adsorption towers

KURION adsorption tower

SARRY adsorption tower
Storage of the SARRY adsorption towers

The following materials were selected for developing the Research Program related toCorrosion experiments implementation: steel – 316L; zeolite – Clinoptilolite.
3

Results of preliminary Data accumulation and study (related to the
KURION/SARRY design features as well as storage conditions) (2/2)
The following main requirements were formulated for Research Program Development:
Specific activity of β/γ-containing components (90Sr / 137Cs) should be equal to ~ 108 Bq/g;
Welded model samples should model as butt weld as O-like welded joint (to check thepossibility of crevice corrosion development for KURION adsorption towers geometricalconditions);- It is required to provide the following contact types for crevice corrosion experiments
Implementation: Metal – Metal contact type, Metal – Non-metal contact type;- Welding operations (when manufacturing the model samples) should be performed without
additional thermal processing;- The following details related to the welding conditions were taken into account:
For
KURION–
Weld
fillermetal:ASME
SFA-5.9
ER316LSi(Rootpass)/ER316L(Subsequent pass); Carbon≦0.02 wt.%, δ-ferrite 9-11 wt.%. Welding conditions:
Root pass : Gas Metal Arc Welding; Subsequent pass : Submerged Arc Welding.
For SARRY – Weld filler metal: WEL TIG 316L(Japanese welding rod), Carbon<0.02 wt.%,
δ-ferrite 10-12 wt.%; Welding conditions: Root pass (root area formation):10～12kJ/cm, TIG
welded in Argon atmosphere, Subsequent pass (formation of the remaining part of a weld): 10～
15kJ/cm, TIG welded in Argon atmosphere (both side), not using backing plate-

O-like welded joint of the KURION adsorption tower

4

Longitudinal welded joint of the SARRY adsorption towerReport development on the Russian side’s experience
Report Content:(a) Description of the Russian side’s experience in thefield of corrosion processes study;
The following corrosion mechanisms were considered:- Hydrogen cracking of Zr-containing alloys- Stress corrosion cracking studies results- Intergranular corrosion cracking- Corrosion studies of structural and fuel materials(b) Application of Russian side’s experience to consider
the occurrence of the considered corrosion processes
under the conditions of the KURION/SARRY storage

(a)

(b)

External appearance of the RBMK’s RPS
channel in the zone of the process failurefrom the side of the adapter (a) and thepipe (b)The following corrosion mechanisms were selected for
the Research Program development:- Crevice corrosion;- General(uniform) corrosion;- Pitting corrosion;- Intergranular corrosion;- Stress corrosion cracking.
5Research Program Development
The main purpose of Research Program is to select and assess the methods andequipment required for preparation and implementation of the experiments related tothe accelerated occurrence of the selected corrosion processes. The scope of experiments(provided by Research Program) should be sufficient for further development of thePrediction Model as well as Countermeasures Plan.
Research Program

Requirements forcorrosion experiments
without β/γ-radioactivity

Requirements for corrosion
experiments with β/γradioactivity

Implementation of the corrosion experiments
at the 2 different Research sites (INM site and
CNIITMASH site) to provide a crossverification of the experimental data

The presence of β/γ-activity is provided by saturation of clinoptilolite with 90Sr and 137Cs
6

Research Program Development
INM’s Scope of work
Type ofcorrosion

The stateof thesteel

Type ofcontactТ, оС1General(uniform),
Pitting

2
Homoge
neous

3
-

4
25, 70

5100,
10000,
29000

6
0, ~4·108

Homogeneous-

25, 70100,
10000,
29000
100,
10000,
29000

0, ~4·108

100,
10000,
29000
100,
10000,
29000

0, ~4·108

100,
10000,
29000

0, ~4·108

General(uniform),
PittingCreviceParameters of experiments
Type of the tower Number[Cl-],
А, Bq/g t, h/ σр KURION/ SARRYof theppm
samples(EPR,P)With
weldedjoint *)-

25, 70With
weldedjoint *)
Homogeneous-

25, 70Homogeneous(EPR,P)
М-NМ
(ASTM G7801)

25, 70М-NМ
(ASTM G7801)(ASTM G19208)

25, 70Accepted Legend:
D: irradiation dose;*): welded joint of steel AISI 316L;
M-NM: metal-nonmetal

0, ~4·108

0, ~4·108

7
8
1000,
+/+
2000,
+ - means
3000, consideration for
5000 certain tower type
0,
+/+
1000,
5000
1000,
+/+
2000,
3000,
5000
0,
+/+
1000,
5000
1000,
+/+
2000,
3000,
5000
0,
+/+
1000,
5000

Control Methods to be used

Type ofthe sample

9
48

10
Visual inspection, photo,gravimetry, Optical
metallography, SEM/EDX

11
3-1

36

EPR,P= EPR,P=f(Cl-,A,t,D,T)
before and after the
1000/5000-hour test
Visual inspection, photo,gravimetry, Optical
metallography, SEM/EDX

3-12

EPR,P= EPR,P=f(Cl-,A,t,D,T)
before and after the
1000/5000-hour test
Visual inspection, photo,gravimetry, maximum depthof corrosion, Optical
metallography, SEM/EDX
EPR,CR= EPR,CR=f(Cl-,A,t,D,T)
before and after the
1000/5000-hour test

3-13

48

36

48

36

3-2

3-3 +2sleeves3-10 +2
sleeves7

Research Program Development
INM’s Scope of work
Table continuation
Type ofcorrosion

Thestate of
the
steel
2
With
weldedjoint *)

Type of contact

Parameters of experiments

Type of the
towert, h/ σрKURION/
SARRY
781000, 2000,+/+
3000, 5000

Numberof thesamples

Control Methods to be
usedType ofthesample10
Visual inspection, photo,gravimetry, maximum
depth of corrosion,
optical metallography,
SEM/EDX
36
EPR,CR= EPR,CR=f(Cl-,A,t,D,T)
before and after the
1000/5000-hour test
48
Visual inspection, photo,gravimetry, maximum
depth of corrosion,
48х2=96 optical metallography,
SEM/EDX11
3-4+2
sleevesТ, оС[Cl-], ppm

А, Bq/g3
М-NМ
(ASTM G78-01)

425, 70

5100,
10000,
29000

6
0, ~4·108

With
М-NМ
welded (ASTM G78-01)
joint *) (ASTM G192-08)
CreviceWithМ-Мwelded (ASTM G78-01)
joint *)
WithМ-Мweldedjoint **)
Stress
Homogecorrosion neous
cracking
StressWith
corrosion weldedcracking
joint *)

25, 70100,
10000,
29000
100,
10000,
29000
100,
10000,
29000
100,
10000,
29000
100,
10000,
29000

0, ~4·108

0, 1000,
5000+/+

0, ~4·108

1000, 2000,
3000, 5000+/-

0, ~4·108

1000, 2000,
3000, 5000+/+

0, ~4·108σр=0,5σ0,2,
σр=0,75σ0,2,
σр=1,0σ0,2
σр=0,5σ0,2,
σр=0,75σ0,2,
σр=1,0σ0,2

+/+

108

tcr= f(Cl-,A,t,T,D,σ)

3-14

+/+

108

tcr= f(Cl-,A,t,T,D,σ)

3-15

1Crevice25, 7025, 7025, 7025, 70Accepted Legend:*): welded joint of steel AISI 316L;**): welded joint of KURION adsorption tower;
D: irradiation dose;
M-M: metal-metal;
M-NM: metal-nonmetal

0, ~4·108948

3-11+2sleeves
3-4 + 37(3 mm)
3-68

Research Program Development
INM’s Additional Scope of work
It is planned to consider the 3rd temperature (50 ˚C) for several types of studied corrosion
processes in the conditions of absences of radioactivity. The absences of radioactivity willallow to show the required Arrhenius dependence as well as simplify the implementationof Additional scope of work.
The scope of additional work is presented in the table form:
Type of Corrosion/Typeof repassivation
potential
Pittting corrosion

Points of Time,h

Points of [Cl-],
ppm

T, ˚C

Number of model samples
to be used

The use ofradioactivity

0, 3000

50

Repassivation potential
for pitting corrosion
Crevice corrosion

0, 1000

1000, 5000,
20000
1000, 5000,
20000
1000, 5000,
20000

Without use ofradioactivity
Without use ofradioactivity
Without use ofradioactivity

Repassivation potential
for crevice corrosion

0, 1000

1000, 5000,
20000

50

Type 3-1: 3 pcs,
Type 3-2: 3 pcs,
Type 3-12: 6 pcs,
Type 3-13: 6 pcs
Type (3-3: 3 pcs + 3-4: 3 pcs)
– contact «metalnonmetal»+12 washers;
Type (3-4: 3 pcs+ 3-7: 3 pcs) –contact «metal-metal»;Type 3-10: 6 pcs;
Type (3-11: 6 pcs) - contact«metal-nonmetal». + 24
washers

0, 3000

50
50

Without use ofradioactivity

9Research Program Development
CNIITMASH’s Scope of work
Type ofcorrosion

State of themetal

Number of
the samples

а, mmlength

b, mm
width

c, mm
thickness

Type of Drawing

60

50

20

3

3-1

60

50

20

3

3-2

60

30

30

3

60

30

30

3

steel 316L

6

-

-

-

Steel sheet - 3 mm,steel 316L

12

80

20

3

Initial material

Steel sheet - 3 mm,steel 316L
Steel sheet - 10 mm,
Pittingsteel 316L, welding
Welded joint
wire OK Autrod 316L +OK Flux10.92
Steel sheet 3 mm, steel
Homogeneous
316L
Steel sheet - 10 mm,
steel 316L, welding
Welded joint
wire OK Autrod 316L +Crevice
OK Flux10.92
Homogeneous

Model tank

Intergranu
HomogeneouslarMode of experiment
implementationt=20±1 ᵒC (glass container)),the volume solution/sample
surface ratio = 10:1. Duration is
up to 72 hours
Solution: 10% solution of FeCl3

t=20±1/60±1 ᵒC (glass
container),the volume solution/sample
surface ratio = 10:1. Duration is
3-430, 60, 90 days. [Cl-] 10, 9505,
19 000 ppm
Solution is poured in the Model
Model Tank astank. t=20±1/60±1 ᵒC. Durationassembly
500 -3000 hours. [Cl-] 10, 9505,
19 000 ppm
Preliminary heating up (650 ᵒC,
1 hour). The boiling of solution
with adding of the copper chips
is implemented within the 8hours. Z-like bend of the sample(80±0,5)x(20±0,5)x(3is used.
±0,2) mmSolution: It is planned to add
the copper sulphate (50±0.1) g
to (1000±3) cm3 of water aswell as small portions of sulfuric
acid (250±3) cm3
3-3

10

Research Program Development
Model Samples Description – Model Samples shape selection
Type: 3-1 Steel 316 L
Related standard: GOST R 9.905-2007

Type: 3-13 Steel 316 L
Related standard: GOST 9.912-88

Type: 3-12 Steel 316 L
Related standard: GOST 9.912-88

Type: 3-3 Steel 316 L
Related standard: ASTM G 78-01

Type: 3-2 Steel 316 L
Related standard: GOST R 9.905-2007

Type: 3-10 Steel 316 L
Related standard: ASTM G 192-08

11

Research Program Development
Model Samples Description – Model Samples shape selection
Type: 3-4 Steel 316 L
Related standard: ASTM G 78-01

Type: 3-11 Steel 316 L
Related standard: ASTM G 192-08

Type: 3-6 Steel 316 L
Related standard: GOST R 9/905-2007

Type: 3-14 Steel 316 L
Related Standard OST 108.90101.79

Type: 3-7 Steel 316 L
Related standard: ASTM G 78-01

Type: 3-15 Steel 316 L
Related Standard OST 108.90101.79

Crevice Washer

12Corrosion Experiments Preparation
The selected scope of the experiments (see slides 7 - 9) implies the implementation of the hot experiments related
to a certain set of the controlled parameters: t, h; T, ˚C; [Cl]- ppm; A Bq/g - such a set of the controlled parameters
is one experimental point.
In order to optimize Hot Cell working volume filling it is planned to use the single assembly allowing to install all
the required samples for each experimental point.

Uniform/Pitting
corrosion

Samples type3-1, 3-2, 3-12, 3-13

Crevice corrosion

Samples type 3-3,
3-4, 3-10, 3-11,
3-7, 3-6 + Washers

Stress corrosion
cracking

Samples type3-14, 3-15

(t, T, [Cl-], A)

1 -panel, 2- handle, 3- bushing (slot-forming device), 4, 9 - washer,
5 - high washer, 6, 7 - bolt, 8 - nut, 10 - screw, 12 - crucibles withsamples type 3-10 and 3-11
The assembly related to the certain experimental point

13

Corrosion Experiments Preparation
Description of Approach on Corrosion tests implementation
Then each assembly is installed in the container

An overall view of a container with installed
assembly for corrosion experiments

The cross-section of the assembly
installed in the container

A scheme of samples installation inside the container
Container for corrosion tests

Panel with installed samples (topview)

Panel with installed samples(side view)

Container for corrosion tests with installed assembly14Corrosion Experiments Preparation
Details related to crevice corrosion
The scheme of crevice corrosion experiments implementation

Sample type 3-3, 3-4 assembling (multi-crevice
experiment) in accordance with standard ASTM G-78

Sample type 3-6

before adding zeolite

after adding zeolite

Samples type 3-10, 3-11 for defining therepassivation potential of crevice corrosion

The surface
roughness of the
manufactured
samples is equal to
1.6 μm (Ra=1.6 μm),
Thus the studied
crevice gap is equal
to units of
micrometer
Despite the fact that the
distance between two walls
is in the shown range 0.5 -1
mm, there is the possibilityof presence of the crevice
gaps equal to tens of
micrometer in areas locatedclose to the welded joint.
These areas are planned to
be studied.
It is planned to
implement theadditional study (using
the optical microscope)of the sample’s
surfaces in order todefine that themeasured value ofrepassivation potential
is related to the
15gap
consideredCorrosion Experiments Preparation

Dimensions control

Samples weighting

Sample type 3-3

Samples type 3-4 + 3-7

Sample type 3-12

Electrochemical cell assembling

Sample type 3-10

Samples assembling
16

Corrosion Experiments Preparation

Samples are fixed on the panel

Installation of the samples inside the container

Container Filling (withzeolite) related toRepassivation Potential
Measuring (crevice
corrosion)

Collection of the prepared container

Container filling with Zeolite

17

Corrosion Experiments Preparation

Manipulator

Container
Thermostatic
equipment

Hot Tests Implementation. Required set of the prepared containers andthermostatic equipment are installed inside the Hot Cell

Container
Thermostatic
equipment

Cold Tests Implementation. Required set of the
prepared containers and thermostatic equipment are
installed inside the Thermostatic Equipment

18

Corrosion Experiments Preparation
An Approach to Model Tanks Fragmentation
It is required to implement the Model Tanks fragmentation in order to provide the subsequent analysis of crevice corrosion
occurrence. It is planned to implement preliminary analysis of the welded joint state using the microscope. In order toprovide the access to the welded joint, the model tank is prepared in accordance with the following approach:
It is planned to use
theopticalmicroscope
OLYMPUS SZ-61 thatwill provide the 5-20
times magnification

An overall view of the Model Tank

- A line showing the approach forpreliminary cutting of the model tank toprovide the visual control using the
microscope. As a result, the areas for
subsequent detailed metallographic control
will be selected

The technology of manufacturing of
the model tanks doesn’t exclude thepresence of smaller gaps (gaps equal
to tens of micrometer) in the areas
close to the welded joint root (thisfact will be defined after cutting thesamples when corrosion tests arecompleted). Such areas are planned
to be studied.

An example of a view of surface state in the gap
between the bottom and the shell

19Experimental Results
CNIITMASH Site. Pitting corrosion (1/2)
Experiments related to the pitting corrosion (In accordance with Russian Standard GOST 9.912-89 – equivalent of
the Method A of ASTM G 48). Experiments under the conservative conditions to assess the tendency of 316L steel topitting corrosion.
Type of sample

Dimensions, mm

Number of the samples

Solution

Duration, hTemperature, ˚CFlat sample without welded joint

50x20x3

5

10% FeCl3∙6H2O

72

20±1

Flat sample with welded joint

50x20x3

5

Samples before experiment

20

An overall view of the samples after the experiments

Front side

Opposite side

Samples before experiment

Samples without welded joint

Front side

Initially, obtained pittings
are closed with «lids».
Thus, when experiment
had just been finished thesamples surfaces look like«shiny steel»shiny sample surfaces

Opposite side

Samples with welded joint

Experimental Results
CNIITMASH Site. Pitting corrosion (2/2)
Type of sample

Average rate of pitting
corrosion, g/m2h

Maximal depthof a pitting, mm

Flat sample without welded
joint

3.3±0.4

1.7

Flat sample with welded joint

2.9±1.2

1.8

It should be noted, that it has been obtained that the areas of more extensive development of pitting corrosion
are along the sample’s ends surface as well as close to hole that in general corresponds to accepted standards.
Crevice corrosion wasn’t identified in the areas of contact with fluoroplastic thread (that provide the sample
hanging), due to the fact that diameter of the fluoroplastic thread is much smaller then hole diameter.

General Tendency of AISI 316L steel to pitting corrosion has been identified.

21

Experimental Results
CNIITMASH Site. Intergranular corrosion (IGC)
Experiments related to the Intergranular Corrosion (In accordance with Russian Standard GOST 6032-2017). GOST 6032-2017
has the following features compared with other standards (EN ISO 3651-2, ASTM A262:2014, JIS G0575:1999): preliminary
heating – 650 ˚C during 60-min period, experiment duration – 8 hours, angle of sample bending – 90˚. Conditions: boiling water
solution of CuSO4∙5H2O (50±1g) and H2SO4 (250±3g) with presence of metallic Cu; Duration of boiling ~ 8 hours.

The state of base metal after experiment is finishedThe state of weld metal after the experiment is finished

Non-welded Samples before the experiment

Welded Samples before the experiment

The boundaries ofaustenitic grains were
not destroyed after the
IGC experiments are
finished. Based onthese results, it was
concluded that the weld
metal of heat-affectedzone (HAZ) and the basemetal don’t havetendency to IGC.
Microstructure of theweld metal

Microstructure of the
HAZ material

Microstructure of thebase material

Tendency of the studied metal to intergranular corrosion hasn’t been identified22

Experimental Results
CNIITMASH. Crevice corrosion (in accordance with ASTM G 78) (1/4)
Experiments related to the crevice corrosion (In accordance with Standard ASTM G 78).
Type of sample

Dimensions, mm

Number of thesamples

Solution

Duration,d

Depth of washer’sgroove (h), mm

Temperature, ˚CFlat sample without
welded joint

30x30x3

5490

0.2/0.3/0.5

25±5/60±2

Flat sample with welded
joint

30x30x3

54

1 – [Cl-] = 10 ppm
2 - [Cl-] = 9500 ppm
3 - [Cl-] = 19 000
ppm

Area of crevice corrosion, S mm2
Temperature, ˚C

2560[Cl-], ppm

10

9500

19000

10

9500

19000

h = 0.2 mm

0.00

26.50

40.75

0.75

16.62

38.00

h = 0.3 mm

0.00

33.20

71.50

0.00

6.25

32.00

h = 0.5 mm

0.00

15.25

47.00

0.00

0.00

27.00

Mass loss per surface area of sample, Δm/S g/mm2
Temperature, ˚C

2560[Cl-], ppm

10

9500

19000

10

9500

19000

h = 0.2 mm

0.00

1.44

1.94

0.74

1.50

3.29

h = 0.3 mm

0.00

1.93

3.74

0.00

0.86

2.16

h = 0.5 mm

0.00

1.93

2.72

0.00

0.00

1.94
23

Experimental Results
CNIITMASH. Crevice corrosion (in accordance with ASTM G 78) (2/4)
1 – [Cl-] = 10 ppm;
2 - [Cl-] = 9 500 ppm;
3 - [Cl-] = 19 000 ppm(a) For T = 25 ˚C(a) For T = 60 ˚CGraphical interpretation of the dependencies of S mm2 (surface of crevice corrosion foci) and Δm/s g/mm2(mass loss)
24

Experimental Results
CNIITMASH. Crevice corrosion (in accordance with ASTM G 78) (3/4)
Overall view of some samples after completion of the crevice corrosion experiments:

Sample № 98 will beconsidered in detail on slide№ 26(a) Front side, (b) Opposite side
Solution: 3, t = 60 ˚C
Washer’s groove 0.2 mm(a) Front side, (b) Opposite side
Solution: 2, t = 25 ˚CWasher’s groove 0.2 mm
25

Preliminary Experimental Results
CNIITMASH. Crevice corrosion (An example of analysis) (4/4)
Study of the sample № 98:

Scanning line

Dcr,max = 33.6 μm

Dcr,max Is the maximal depth of crevice corrosion

26

Experimental Results
CNIITMASH. Crevice Corrosion. Model Tanks (1/4)
Use of Automatic welding method led to appearance of a defect called «incomplete welding». After that,
additional Model Tank was manufactured (using the Manual Welding Method) in order to avoid such a defect,
thus Model Tank with/without incomplete welding defect were analyzed.
A scheme of the manufactured Model Tanks:

Shell

Root area of thewelded joint

BottomPrepared metallographic Specimen
Model Tank

Conditions of an experiment

Model Tank 1

T = 25±5 ˚C, [Cl-] = 10 ppm;

Model Tank 2

T = 25±5 ˚C, [Cl-] = 9 500 ppm;

Model Tank 3

T = 25±5 ˚C, [Cl-] = 19 000 ppm;

Model Tank 4

T = 60±2 ˚C, [Cl-] = 10 ppm;

Model Tank 5

T = 60±2 ˚C, [Cl-] = 9 500 ppm;

Model Tank 6

T = 60±2 ˚C, [Cl-] = 19 000 ppm;

The width ofcrevice area related
to the incomplete
welding is equal to5 - 50 μm

An example of incomplete welding. Model Tank 6

10-μm-like defects (in the root area of the welded joint) are most interesting areas from the point of view of crevice corrosion
27
development.

Experimental Results
CNIITMASH. Crevice corrosion. Model Tanks. Example of crevice Corrosion
formation (2/4)
Analysis of the crevice corrosion development in case of presence of the defect (incomplete welding).
Model Tank №6 - [Cl-] = 19 000 ppm. T = 60 ˚C, t = 3000 hours.

10 μm

The presence of etched areas inside the defectrelated to the incomplete welding

SEM+EDSIn the crevice gap of defect there is a selective Fe dissolution (Fe goes into solution in the form of ions and forms acorrosion product already at the exit of the crevice gap) as well as enrichment of the surface with elements that are
more stable under these conditions (Cr, Mo) due to their greater tendency to transition to a passive state, which
confirms the strengthened occurrence of crevice corrosion (anodic dissolution). The presence of Si is explained by thefact that the root area of the welded joint was created using a Si-containing ER316LSi welding wire. Al, Si, Mn,
Ca can28
get into the defect area from the flux OK FLUX 10.92 (Flux OK FLUX 10.92 - Neutral agglomerated chromocompensating
flux used in welding).

Experimental Results
CNIITMASH. Model Tanks. Features of crevice Corrosion formation(3/4)
Development of crevice corrosion depends not only on the defect width but also it depends on its configuration(presence of transition area).
The influence of transition area is also modelled by using the varied
value of washer’s groove depth (h):Incomplete weldingareaTransition area

Technological gap

The dependence of mass loss (Δm/S) from the value h under the following
conditions: T = 25 ͦС (left side) and 60 ͦС (right side): 1 - [Cl-] = 10 ppm;
2 - [Cl-] = 9500 ppm; 3 - [Cl-] = 19000 ppm.
Duration : 90 days (in accordance with ASTM G 78).

The overall view of the samples tested under the following
29
conditions: [Cl-] = 10 ppm, T = 60 ˚CModel Tank № 4 ([Cl-] =10 ppm, T = 60 ˚C, t = 3000 h)

Experimental Results
CNIITMASH. Model Tanks. Features of crevice Corrosion formation(4/4)
Development of crevice corrosion depends not only on the defect width but also it depends on its configuration. An example ofcrevice corrosion presence/absence inside the same Model Tank. Model Tank 6. Sample 6: [Cl-] = 19 000 ppm. T = 60 ˚C, t =3000 hours:

Crevice corrosion presence:

Crevice corrosion absence:

The presence of transition area (width = 0,1 – 0,3 mm) located between technological gap and a gap formed by incomplete
welding has quite a significant impact on crevice corrosion intensity. This finding has a good corresponding with results obtained
during the experiments described in the item (a) in case of using the washer’s groove equal to 0.2 mm. The process of crevice
corrosion formation in the incomplete welding area is a stochastic one (in spite of same conditions, crevice 30
corrosion
could/couldn’t be formed in the considered areas).

Experimental Results
INM. Uniform/Pitting Сorrosion. Examples of Samples appearancet, hBeforetest

70 оС without radiation
100 ppm

10 000ppm

29 000ppm

70 оС with radiation
100 ppm

10 000ppm

29 000ppm

10001200

17282064

31

Experimental Results
INM. Uniform/Pitting Сorrosion
Pitting corrosion without radiationt, h1100-1200

2000-2064

3024

4056-4152

T, oC

D, MGy

0

0

0

0

25

70

[Cl-], ppm

100

10000

29000

100

10000

29000

Metal

No*

No

No

No

No

No

Welded joint

No

No

No

No

No

No

Metal

No

No

No

No

No

No

Welded joint

No

No

No

No

No

No

Metal

No

No

No

No

No

No

Welded joint

No

No

No

No

No

No

Metal

No

No

No

No

No

No

Welded joint

No

No

No

No

No

No

* - No = no pitting corrosion

32Experimental Results
INM. Uniform/Pitting Corrosion
Pitting corrosion with radiation
t, h

1000

17282000
3024
40564152

D, MGy~0.87~1.5-~1.7
~2.6

~3.6

T, oC

25

70

[Cl-], ppm

100

10000

29000

100

10000

29000

Metal

No*

No

No

No

No

No

Welded joint

No

No

No

No

No

No

Metal

No

No

No

No

No

No

Welded joint

No

No

No

No

No

No

Metal

No

No

No

No

No

No

Welded joint

No

No

No

No

No

No

Metal

No

No

No

No

No

+**

Welded joint

No

No

No

No

No

+**

* - No = no pitting corrosion,** - + = Pitting observed33Experimental Results
INM. Crevice Corrosion. Results for experiments without radiation
Crevice corrosion without radiation (in μm)t, h11001200

20002064

3024

4152

D,
MGy

Material

0

0

0

0

T, oC

25 oC

70 oC

[Cl-], ppm

100

10000

29000

100

10000

29000

Metal

Metal/nonmetal

No*

7.6…11.3

31.7..58.6

No

29.0…33.2

12.5…38.6

Welding

Metal/nonmetal

No

No

15.4

No

15.4…25.3

22.6…42.0

Metal

Metal/metal

No

No

No

7.3

No

18.4

Metal

Metal/nonmetal

No

9.3…10.6

16.6…17.5

No

14.4…15.0

148.3…173.4

Welding

Metal/nonmetal

No

4.6…7.7

7.4…17.0

No

29.1

35.2

Metal

Metal/metal

No

No

No

No

No

+ (n.d)**

Metal

Metal/nonmetal

No

5.6…15.6

15.6…18.2

2.1

31.6…56.0

34.9…77.0

Welding

Metal/nonmetal

No

9.8…23.9

5.4…10.6

No

17.2

22.8

Metal

Metal/metal

No

No

No

7.1

No

22.9

Metal

Metal/nonmetal

No

11.3

7.4…26.2

3.7

31.6…56.0

87.8…160.0

Welding

Metal/nonmetal

No

7.6

5.6…7.4+ (n.d)21.4…30.4

24.4

Metal

Metal/metal

No

No

No

No

No

+ (n.d)* - No = no crevice corrosion,** - + (n.d.) = crevice corrosion observed (depth of crevice corrosion no dementing)34

Experimental Results
INM. Crevice Corrosion. Results of experiments with radiation
Crevice corrosion with radiation (in μm)
t, h

1000

17282000

3048

40564152

D,
MGy

Material~0.87~1.5~1.7

~2.6

~3.6

T, oC

25 oC

70 oC

[Cl-], ppm

100

10000

29000

100

10000

29000

Metal

Metal/nonmetal

No*

11.2…23.7

23.7…61.9No

9.9…69.7

19.9…30.7

Welding

Metal/nonmetal

No

8….26.7

17.4….58.3

No

12.3..28.9

12.7…41.3

Metal

Metal/metal

No

No

No

No

No

+ (n.d)**

Metal

Metal/nonmetal

No

9.9…14.3

21.4…77.7

No

19.1…24.2

10.0…19.0

Welding

Metal/nonmetal

No

8.0…13.9

10.7…19.3

No

21.0…27.1

28.4…46.1

Metal

Metal/metal

No

5.1

4.2

No

No

2.6

Metal

Metal/nonmetal

26.6

12.7…70.0

17.8…35.6

No

18.0…31.5

73.9…90.9

Welding

Metal/nonmetal

11.1

11.2…50.8

10.6…15.0No

36.2…41.4

10.5...16.4

Metal

Metal/metal

No

No

No

No

No

7.6

Metal

Metal/nonmetal

No

15.8…37.7

17.6…22.8

No

20.0…59.8

44.1…87.9

Welding

Metal/nonmetal

No

8.5…19.0

9.0

No

10,6…25.4

29.0…45.9

Metal

Metal/metalNo+ (n.d)**+ (n.d)**No+ (n.d)**+ (n.d)*** - No = no crevice corrosion,** - + (n.d.) = crevice corrosion observed (depth of crevice corrosion no dementing)35

Experimental Results
INM. Crevice Corrosion. Example of implemented analysis (1/2)
T = 25 ˚C. t = 2000 h. [Cl-] = 100 ppm. Welded joint. With radiation

A

B
Front side

Lext image
Front side

Opposite side

Lext image

Lext image
Area B Scanning lines

Lext image
36
Area A, Scanning lines (see slide No37)

Experimental Results
INM. Crevice Corrosion. Example of implemented analysis (2/2)
Sample No 426. Welded joint. T = 25 ˚C. t = 2000 h. [Cl-] = 100 ppm. With radiation. Area A. Profiles in accordancewith the selected scanning lines (Dcr,max - the maximum depth of crevice corrosion)

Lext image

Dcr,max = 0 µm

Lext image

Heightprofile, µm

Lext image

Dcr,max = 0 µm
Characteristic types of scanning profile
along lines in any directions.
There is no crevice corrosion.

Dcr,max = 0 µm

Lengthprofile, µm

Lext image

Lext image

Dcr,max = 0 µm

Dcr,max = 0 µm

37Experimental Results
INM. Crevice Corrosion. Samples type 3-6 made of fragmented Model Tanks.
Example of the Implemented study (1/4)
70 oC, with radiation

Before test[Cl-]
100 ppm
1008 h2016 h3024 h1008 h2016 h3024 h2016 h3024 h[Cl-]
10 000 ppm[Cl-]
29 000 ppm

Product
corrosion

1008 h

Product
corrosion
38

Preliminary Experimental Results
INM. Crevice Corrosion. Samples type 3-6 made of fragmented Model Tanks.
Example of the Implemented study (2/4)
Sample № 623, T = 70 оС, [Cl-] = 29 000 ppm, t = 3048 h, without radiation
Appearance
Lext*
investigation
Bоttom

Shell

Shell

Shell

Welded joint
Refer to the lower left photoon p. 40

In the gap between
Shell and Bottom,
crevices andcorrosion products
haven’t been
indicated.

*Lext – Laser
confocal scanningmicroscope
OLYMPUS LEXT
OLS5000

Welded joint
Welded joint

Bottom

Bottom
Shell

Shell
Welded joint
Welded joint
Bottom

Bottom39

Preliminary Experimental Results
INM. Crevice Corrosion. Samples type 3-6 made of fragmented Model Tanks.
Example of the Implemented study (3/4)
Opposite side Front side
A sample for study using Lext

Welded joint’s metal is fused withshell/bottom metall.
Crevices/Corrosion products haven’t
been identified.
Refer to the lower left photo

Shell
BottomWelded joint
40

Preliminary Experimental Results
INM. Crevice Corrosion. Samples type 3-6 made of fragmented Model Tanks.
Example of the Implemented study (4/4)
A sample № 623, T = 70 оС, [Cl-] = 29 000 ppm, t = 3048 h, without radiation

8

9

7

65

4

3

2 1

Scanning the profiles has been implemented by using the confocal laser microscope in order to define the presence of еру beginning of areas ofincomplete welding as well as presence of crevice corrosion (enlarged views of profiles of the zones that are close to boundaries between welded joint
and bottom parts):

shell

1

2

3

4

Welded joint in a gap

bottoma zone with biggest (but notsignificant) changes of a scanningprofile end. The beginning of anarea of incomplete welding andpresence of crevice corrosion in it
hasn’t been identified.
a line of transition from welded
joint to bottom side has quite asmooth profile. The beginning of anarea of incomplete welding andpresence of crevice corrosion in it
hasn’t been identified.
a line of transition from welded
joint to bottom side has quite asmooth profile. The beginning ofan area of incomplete welding andpresence of crevice corrosion in it
hasn’t been identified.
this scanning line transits totilted plane of the bottom side.
The beginning of an area ofincomplete welding and presenceof crevice corrosion in it hasn’t
been identified.

41

Experimental Results
INM. Stress Corrosion cracking (1/6)
Sample1.0σ0.20.75σ0.2
Bolt (oxidized Ti)
Shell (oxidized Ti)
Welded joint sample

0.5σ0.2

1.0σ0.20.75σ0.2

0.5σ0.2

SCC installation as an assembly

Welded joints

Inserts (oxidized Zr)

Homogeneous metal

Homogeneous
sample42

Experimental Results
INM. Stress Corrosion cracking (2/6)

25 оС Without Radiation[Cl-]=100 ppm[Cl-]=10 000 ppm[Cl-]=29 000 ppm

1000 hHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

Welded2000 hHomogeneous

Welded3000 hHomogeneous

Welded43

Experimental Results
INM. Stress Corrosion cracking (3/6)

70 оС Without Radiation[Cl-]=100 ppm[Cl-]=10 000 ppm[Cl-]=29 000 ppm

1000 hHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

Welded2000 h3000 h44

Experimental Results
INM. Stress Corrosion cracking (4/6)

25 оС with radiation[Cl-]=100 ppm

1000 h,~0.87 MGy Homogeneous

2000 h,~1.7 MGy

3000 h,~2.5 MGy

Welded[Cl-]=10 000 ppm[Cl-]=29 000 ppm

Homogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

WeldedHomogeneous

Welded45

Experimental Results
INM. Stress Corrosion cracking (5/6)

70 оС with radition[Cl-]=100 ppm

1000 h,~0.87 MGy Homogeneous

2000 h,~1.7 MGy Homogeneous

3000 h,~2.5 MGy Homogeneous[Cl-]=10 000 ppm[Cl-]=29 000 ppm

WeldedHomogeneous

WeldedHomogeneous

WeldedWeldedHomogeneous

WeldedHomogeneous

WeldedWeldedHomogeneous

WeldedHomogeneous

Welded46

Experimental Results
INM Stress Corrosion cracking (6/6)
Stress corrosion cracking without radiationt, hD, MGyMaterial

1000

0

2000

0

3000

0

40005000

0T, oC[Cl-], ppm

25

70

100

10000

29000

100

10000

29000

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCCStress corrosion cracking with radiationt, hD, MGyMaterial
1000

~0.87

2000

~1.7

3000

~2.5

40005000~3.4-4.25

T, oC[Cl-], ppm

25

70

100

10000

29000

100

10000

29000

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC

Homogeneous metal

No SCCNo SCCNo SCCNo SCCNo SCCNo SCC 47

Welded joint

No SCCNo SCCNo SCCNo SCCNo SCCNo SCCCorrosion Experiments Implementation
CNIITMASH’s Side. Main Findings
Type ofCorrosion

Type of Samples

Experimental Conditions

Main Findings of the Experiments

Crevicecorrosion

Model Tanks

Six Model Tanks were
manufactured to implement
the crevice corrosion
experiment under thefollowing conditions: T =25±5/ 60±2 ˚C, [Cl-] = 10/9
500/19 000 ppm, duration
3000 h.

The use of the selected process on automatic welding led to presence ofa defect of «Incomplete Welding». The width of crevice of incomplete
welding area is in the following range 5 – 50 μm. Crevice corrosion
development is happened not in the technological gap that is equal to
0.8 – 1 mm (a gap between bottom part and shell part of the Model
Tank) but in the zone of incomplete welding. Herewith, the presence oftransition area (width = 0.1 – 0.3 mm) located between technological
gap and a gap formed by incomplete welding has quite a significant
impact on crevice corrosion intensity. This finding has a goodcorresponding with results obtained during the experiments describedon the slide 49 (crevice corrosion) in case of using the washer’s groove
equal to 0.2 mm. The process of crevice corrosion formation in theincomplete welding area is a stochastic one (in spite of same conditions,crevice corrosion could/couldn’t be formed in the considered areas).

Intergranularcorrosion(IGC)

Plate-likesamples:(80±0.5mm)x(20±0.5mm)x(3±0.2
mm).
Welded/nonwelded samples.

Experiments were
implemented under thefollowing conservative
conditions: preliminary
heating – 650 ˚C during 60min period, experiment
duration – 8 hours, angle ofsample bending – 90˚.
Conditions: boiling water
solution of CuSO4∙5H2O(50±1g) and H2SO4 (250±3g)
with presence of metallic
Cu; Duration of boiling ~ 8hours

In accordance with obtained experimental data, the general tendency ofsteel AISI 316L to IGC hasn’t been identified.

48

Corrosion Experiments Implementation
INM’s Side. Main Findings (1/2)
Type of Corrosion

Type ofSamples

Experimental Conditions

Main Findings of the Experiments

General(Uniform)/
pitting corrosion

Homogeneous
metal –
Sample 3-1,
3-12;
WeldedSample –Sample 3-2,
3-13.

Experiments were
implemented under thefollowing conditions: [Cl-] =100, 10 000, 29 000 ppm, T= 25, 50, 70 ˚C; Duration –1000/2000/3000/5000 h,
samples: welded/nonwelded, with/without
radiation.

General corrosion hasn’t been identified.
Pitting corrosion development has been identified for experiments thathave been implemented under the following conditions:- Experimental duration is more than 4000 hours;- [Cl-] = 29 000 ppm.

Crevice corrosion

Homogeneous
metal –
Sample 3-3,
3-10;
WeldedSample –Sample 3-4,
3-11, 3-7, 3-6.

Crevice corrosion
experiments have been
implemented under thefollowing conditions: [Cl-] =100, 10 000, 29 000 ppm, T= 25, 50, 70 ˚C; Duration –1000/2000/3000/5000 h- The surface of crevice corrosion Development increases as the value of[Cl-] increases;- The pH value has the quite high extent of influence on crevice
corrosion formation;- Under the conditions of β, γ-irradiation, resistance to crevice
corrosion formation for metal-nonmetal contact and for nonwelded/welded samples made of SUS 316L steel at 25 ˚C is preserved only
for tests duration that is up to ~ 1100 hours, and during tests that are
longer than 2000 hours, foci of crevice corrosion begin to appear(including experiments with [Cl-] = 100 ppm).
- In case of increasing the experiment temperature (to 70 ˚C), crevice
corrosion starts appearing (for metal-nonmetal contact) in case of [Cl-]=100 ppm, starting from short exposition time (~ 1000 hours) and inabsence of radiation;- Welded joint (in case of metal-metal contact) has the higher resistance tocrevice corrosion. The first signs of crevice corrosion foci appear only at 70
˚C in water with [Cl-] = 29000 ppm at both exposures of ~ 1000 and ~2000
hours in conditions of irradiation presence/absence.
- The presence of radiation has a high impact on crevice corrosion
formation/development

49

Corrosion Experiments Implementation
INM’s Side. Main Findings (2/2)
Type ofCorrosion

Type of Samples

Experimental Conditions

Main Findings of the Experiments

Stress corrosion
cracking

Homogeneous
metal – Sample
type 3-14 Welded
Sample – Sample
type 3-15 .

Stress corrosion cracking
experiments have been
implemented under the following
conditions: T = 25, 70 ˚C; Loads:
0,5σ0,2 (0,5Rp0.2) – 0.5x300 = 150
MPa; 0,75σ0,2 (0,75Rp0.2) –0.75x300 = 225 MPa; 1,0σ0,2(1,0Rp0.2) – 1.0x300 = 300 MPa.
Welded/ non-welded samples
have been used. Experiments
have been implemented
with/without radiation

Stress corrosion cracking hasn’t been identified

Inserts (oxidized Zr)
SampleAn overall view of the samples. T = 25 C
ͦ , t = 3000 h,[Cl ] = 100 ppm. Without radiation

Bolt (oxidized Ti)
Shell (oxidized Ti)
An overall view of the samples. T = 25 C
ͦ , t = 3000 h,[Cl ] = 100 ppm. With radiation50

Prediction Model Development
Prerequisites for General/Uniform corrosion assessment
The following dependence of the depth of uniform corrosion on time, concentration ofchlorine ions in water and temperature was obtained:
hgc = 4.79 ∙104 ∙t0.5 ∙[Cl-] 0.19 exp(-3660/T)(1)

Where:
hgc – maximal depth of uniform corrosion, mm;
t – duration of an experiment, h;[Cl-] – Cl-ions concentration, ppm;
T – temperature, K

Formula (1) is a result of mathematical processing of the following experimental literature
data on corrosion of 316L steel in seawater with different chlorine ion content obtained using
electrochemical studies:- Malik A.U., Siddiqi N.A., Ahmad S., Andijani I.N. The effect of dominant alloy addition on
the corrosion behavior of some conventional and high alloy stainless steels sea water //Corrosion Science. – 1995. – Vol. 37. – No. 10. – pp. 1521–1535;- Malik A.U., Ahmad S., Andijani I., Al-Fouzan S. Corrosion behavior of steels in Gulf seawater
environment / A.U. Malik, S. Ahmad, I. Andijani, S. Al-Fouzan // Desalination, 1999. – Vol.
123. – pp. 205–213.

51

Prediction Model Development
Incubation Periods (PIT/CIT) Assessment (1/5)
Influence of Cl-ions concentration and experiment duration on crevice corrosion maximal depth change

(a)

(b)

(c)

(d)

а, b – 25 ˚С; c, d – 70 ˚ С; а, c – without irradiation; b, d – with irradiation
Influence of Cl-ions concentration and experiment duration on crevice corrosion maximal depth change

(a)

(b)

(c)

(d)

а, b – 25 ˚ С; c, d – 70 ˚ С; а, c – without irradiation; b, d – with irradiation
Crevice corrosion maximal depth change as a dependence from [Cl-] in case of fixed values of experimental duration
52

Prediction Model Development
Incubation Periods (PIT/CIT) Assessment (2/5)[Cl-]crit, cr – critical concentration of Cl-ions in water meeting the crevice corrosion formation beginning, without
irradiation , ppm;[Cl-]*crit, cr – critical concentration of Cl-ions in water meeting the crevice corrosion formation beginning, with
irradiation , ppm;
t0,cr - incubation period corresponding the crevice corrosion development beginning for conditions without
irradiation, h;t*0,cr - incubation period corresponding the crevice corrosion development beginning for conditions with irradiation,h;Calculated values of [Cl-]crit,cr ( ppm)
T, оС
25

Experimental
conditions
Without
irradiation

With
irradiation

70

Without
irradiation

With
irradiation

Duration ofexperiment, h
1200
2064
3024
4152
1008
1992
3048
4056
1176
2016
3024
4056
1008
1992
3048
4056

[Cl-]crit,cr, ppm
6815
2415
2125
2900
5215
2650
325
6975
5210
4515
1815
435

For conditions without radiation:[Cl-]crit,cr = 1,94 ∙108 ∙t-0.67·exp(-1745/T), R2=0.73; n=6
For conditions with radiation:[Cl-]*crit,cr = 1,34 ∙107 ∙t-1.36·exp(-500/T), R2=0.85; n=5
For conditions without radiation:

t0,cr = exp{(19.08 -1745/T - Ln[Cl-]crit,cr )/0.66}
For conditions with radiation:

t*0,cr = exp{(16.41 + 500/T - Ln[Cl-]*crit,cr )/1.35}
Where T - temperature
53

Prediction Model Development
Incubation Periods (PIT/CIT) Assessment (3/5)
To estimate the incubation period of time required for the formation of pitting and the development ofcrevice corrosion on austenitic chromium-nickel steel, the following expressions are used:

PIT = k·𝟏𝟎

𝑷𝑹𝑬𝑵(𝟏−∆𝑬𝒄,𝒑𝒊𝒕 )𝟐∙𝒍𝒐𝒈[𝑪𝒍−] ,(2)

CIT = k·𝟏𝟎

𝑷𝑹𝑬𝑵(𝟏−∆𝑬𝒄,𝒄𝒓 ),𝟑∙𝒍𝒐𝒈[𝑪𝒍−](3)

Where:
PIT – incubation period before pittings formation, h;
CIT – incubation period before launching the crevice corrosion, h;k – a constant, h;[Cl-] - the chloride concentration, ppm;
PREN – numerical equivalent of stainless steel resistance to local
corrosion, that is calculated as follows:
PREN = %Cr+3.3˖%Mo+16∙%N (3) (for stainless steels with Mo
concentration less then 3% weight);

Ec = 925.45 - 3.2∙(T) + 52.6Log[Cl-](4)

ΔEc,pit = Ec – Epit (5)ΔEc,cr = Ec – Erup (6)Where:
Ec – potential of corrosion, V (SHE),
Epit – potential of pittiing formation, V (SHE),
Erup – potential of crevice corrosion launching, V (SHE)54

Prediction Model Development
Incubation Periods (PIT/CIT) Assessment (4/5)
Epit and Erup have been calculated as follows:
E pit 298  PIN Cl  pH − 7 + log( 1 +  ) − 0.25  log  + 1 +
T + 273  25
25 
 36 

(7)

(8),

where
Epit, Erup, T, [Cl] – description is shown on the slide № 54,
ν – a speed of water moving, m/s;
PIN - Pitting Initiation Number, is a function of stainless steel composition
PIN = PREN - 0.1%Mn - 100%S
Processing of electrochemical measurements of the pitting corrosion of 316L steel gives the following
expression for the difference in the pitting resistance bases of base metal samples in watercontaining chlorine ions:

ΔEb – ΔE*b = 972.7 – 157.3Log[Cl-] – 0.75T; R2=0.98; n=6

(9)

where
ΔEb - pitting resistance base for conditions without radiation, mV
ΔE*b - pitting resistance base for conditions with radiation, mV[Cl-] – Cl-ions concentration, ppm
T – temperature, K(7), (8) - Luciano Lazzari. Engineering Tools for Corrosion. Design and Diagnosis European
Federation of Corrosion (EFC). Series 2017. 4 - Pitting and Crevice Corrosion. Pages 61-80.
DOI: http://dx.doi.org/10.1016/B978-0-08-102424-9.00004-5.

55

Prediction Model Development
Incubation Periods (PIT/CIT) Assessment (5/5)
Results of PIT calculation (in hours, in accordance with expressions (2), (4), (5), (7), (9)Mediumconditions
Without
radiation
With radiation

Т, оС
25
50
70
25
50
70

10
3.90E+27
3.96E+25
1.27E+24
1.08E+20
1.89E+18
9.42E+16100
9.07E+12
1.04E+12
2.05E+11
1.52E+10
2.31E+09
5.65E+08[Cl-], ppm
300
1000
8.36E+09 4.39E+07
1.60E+09 1.23E+07
4.57E+08 4.65E+06
1.17E+08 2.90E+06
2.79E+07 9.73E+05
9.55E+06 4.28E+05

(а)

10000
7.96E+04
3.52E+04
1.88E+04
3.30E+04
1.67E+04
9.97E+0329000
1.11E+04
5.67E+03
3.36E+03
8.13E+03
4.70E+03
3.07E+03(b)

а – without radiation; b – with radiation

Areas of pitting corrosion resistance as well as tendency to pitting corrosion for steel AISI 316L

In accordance with obtained data, steel AISI316L will be resistant to pitting corrosion.

56

Prediction Model Development
Assessment of crevice corrosion depth (1/2)
Results of CIT calculation (in hours, in accordance with expressions (3), (4), (6), (8), (9)Incubation period values (in hours) before crevice corrosion development beginning for steel AISI316L in
diluted and saturated (in terms of Cl-ions concentration) artificial seawaterТ, оСMediumconditions

25
50
70
25
50
70

Without
radiation
With radiation.

10
1.94E+15
1.42E+14
1.97E+13
2.94E+10
3.06E+09
5.62E+08100
1.85E+07
5.06E+06
1.89E+06
2.46E+05
8.11E+04
3.52E+04[Cl-], ppm
300
1000
2.48E+05 9.67E+03
9.28E+04 4.57E+03
4.37E+04 2.56E+03
1.39E+04 1.54E+03
6.02E+03 8.24E+02
3.20E+03 5.11E+02

(а)

10000
1.94E+02
1.22E+02
8.44E+01
1.07E+02
7.37E+01
5.50E+01

29000
5.74E+01
3.93E+01
2.90E+01
4.65E+01
3.46E+01
2.73E+01(b)
а – without radiation; b – with radiation

Areas of crevice corrosion resistance as well as tendency to crevice corrosion for steel AISI316L
57

Prediction Model Development
Assessment of crevice corrosion depth (2/2)
CIT time dependencies (polynomic dependencies based on the table and graphic data presented on theslide57):
Under the conditions without radiationy(25 ˚С) = 0.1157x4 – 1.7001x3 + 9.6989x2 – 26.962x + 34.131;y(50 ˚С) = 0.1077x4 – 1.5821x3 + 9.0214x2 – 25.063x + 31.665;y(70 ˚С) = 0.1016x4 – 1.4923x3 + 8.5068x2 – 23.625x + 29.801;

Dcr,max - maximal depthof crevice corrosion

Under the conditions with radiation
y*(25 ˚С) = 0.0618x4 – 0.9287x3 + 5.4718x2 – 15.92x + 21.784;
y*(50 ˚С) = 0.0549x4 – 0.8269x3 + 4.8864x2 – 14.272x + 19.644;
y*(70 ˚С) = 0.0497x4 – 0.75x3 + 4.4457x2 – 13.036x + 18.041;
whereу = log(to,cr);у* = log(t*o,cr)
x = log[Cl-] (in ppm).
Mathematical processing of the obtained data

Dcr,max = (1490±5)∙(t-tcr,in)(0.29±0.12)∙[Cl-](0.63±0.09)∙exp(-(3860±240)/T), R2 = 0.95, n = 23.
without radiation

D*cr,max = (9.78±2.33)∙(t-tcr,in)(0.44±0.05)∙[Cl-](0.28±0.05)∙exp(-(1510±160)/T), R2 = 0.92, n = 32.
with radiation

58

Prediction Model Development
Assessment of Stress Corrosion Cracking
To determine the operating time for the first failure of samples made of austenitic stainless steels
due to transcrystalline corrosion cracking, it is recommended to use the following expression:lntкр = lnL – 17.79 – 0.5lnCO2 – 1.5lnCCl + ln[exp{Uo - (σp/21/2 - αGbρ1/2)NAγ }/RT ++ exp{Uo - (σp/21/2 + αGbNρ1/2)NAγ }/RT]
wheretкр – time before first failure of a tube , h;
CO2 and CCl – Cl-ions concentration in water, µg/kg;
Uo – energy of activation of a process of dislocated atom self-

diffusion, kJ/mol (for Russian steel 08Х18Н12Т Uo = 130,94 kJ/mol);γ – activation volume, 10-28 m3;
L – thickness of a pipe wall, mm;
b - Burgers vector (for steel 08Х18Н12Т b = 2,5310-10 m);
ρ – density of dislocations, m-2;
G - shear modulus, N/m2;
NA - Avogadro number;
α - coefficient, α = 0,1;

Influence of Cl-ions concentration on critical time before appearanceof stress corrosion cracking for steel AISI316L

N – number of dislocations in microcluster;R = 8,317 J/(molК) – universal gas constant;
Т - temperature, К;
σp - total tensile stress in metal, kPa.

There is no risk related to the Stress Corrosion
Cracking during the 50-year storage of the
KURION/SARRY adsorption towers
59

Prediction Model Development
50-year Forecast Development. Without radiation
A total corrosion depth (h) has been defined as follows,
where:

h = hgc, if t < CIT; (hgc - general corrosion. See p. 51)
h = hgc + Dcr,max, if t ≥ CIT (Dcr,max see p. 58)..

60

Prediction Model Development
50-year Forecast Development. With Radiation.

There is no risk regarding the integrity loss during the KURION/SARRY adsorption towers storage within their 50-year
61
storage under the 1F’s storage conditions

Prediction Model Development
Applicability Limits of the Prediction Model
As for temperature (T):An Applicable range of T: 10 – 70 ˚C. There is no possibility to extrapolate temperature higher than 70
˚C, due to the fact that in case when temperature is higher than 70 ˚C, a mechanism of corrosion
occurrence will be different – this is due to oxygen dissolution decreasing in water (when T> 70 ˚C).

As for [Cl-]:An Applicable range of [Cl-]: 2 – 29 000 ppm. IN this range of [Cl-] there is a single law ofcorrosion processes occurrence. In case of [Cl-] value higher than 29 000 ppm (in accordancewith existing literature data) there is slowing down corrosion processes – it is due to oxygen
dissolution decreasing in water when [Cl-] > 29 000 ppm.
As for time (t):An Applicable range of t: up to 160 000 hours (to provide the parameters deviation equal todeviations obtained when implementing the experiments). In accordance with accepted theory of
extrapolation robustness, it is allowed to provide the time extrapolation not higher than 1 -1,5
magnitude order of experiment duration. Thus, for our case t = 5000x101.5 = 160 000 hours - in.
this case, the calculated value deviation will correspond to the deviation obtained in theexperiments. When extrapolating beyond this value, the error of the determined value will behigher.
62

Formulation of a countermeasures set
The following countermeasures have been formulated taking into account theobtained 50-year forecast (for a case when there are no risks related to the integrity
loss of the KURION/SARRY adsorption towers during their 50-year storage). Mainly,
formulated countermeasures are related to increasing the created 50-year forecast:❖ It is proposed to implement the calculation of possible values for crevice corrosion
depth (using the expressions obtained during this project) for real operation
parameters of the KURION/SARRY adsorption towers;❖ Based on the calculated data, it is proposed to develop a risk scale on possibility ofintegrity loss for the KURION /SARRY adsorption towers;❖ It is proposed to implement a KURION /SARRY adsorption towers ranking bydegree of risk related to integrity loss;❖ It is proposed to develop a list of organizational and technical measures for eachclass (associated with a certain formulated degree of risk) of the ranked
KURION/SARRY adsorption towers.
.

63

Achieved Results.
Main Findings/Recommendations
Main Findings

Achieved Results
(i)
(ii)

(iii)

(iv)

(v)
(vi)

A full set of data related to the KURION/SARRY adsorption towers
design and storage conditions has been prepared and studied;A set of Corrosion Mechanisms that can affect the integrity of the
KURION/SARRY adsorption during its 50-year storage has beenformulated;
A research Program describing the methodology of corrosion
experiments implementation has been developed (experiments
under the conditions close to the real storage conditions) in order tocollect the required experimental data for Prediction Model
Development;
Corrosion experiments have been implemented (5000-hour
experiments). Experimental data has been processed
Prediction Model has been developed
50-year forecast has been developed/Countermeasures Formulated

(i)

(ii)

(iii)

In accordance with created Prediction
Model as well as 50-year forecast (related
to the KURION/SARRY storage) there is
no expectation regarding the launchingand development of Corrosion Processes
inside the KURION/SARRY adsorption
towers during their 50-year storage (under
the accepted storage conditions).
There is no risk regarding theCrevice/Pitting corrosion launching for thefollowing ranges of storage conditions
during the 50-year storage [Cl-] = 2 -100
ppm, t = up to 70 ˚Cβ/γ activity as well as pH have quite ahigh influence on Corrosion development

Recommendations
(i)
(ii)

Russian side recommends to take into account the KURION/SARRY
operation conditions (operation conditions in the form of the following
dependence T = f(t), [Cl-] = f(t)) in order to improve the Modelling.
Russian side recommends to take into account the formulated
Countermeasures set in order to implement ranking (ranking based on thefollowing parameters- T, [Cl-]) the KURION/SARRY adsorption towers
state (from the point of view of potential risk).

64

Appendix
Logical Schemes of assessment of Pitting/Crevice Corrosion possibility
Crevice Corrosion:

Pitting Corrosion:

65