Reporter:Candidate of ScienceCandidate of ScienceShipkov Andrey AnatolievichHead of Calculation-Analysis Department «Geoterm-EM»

IAEAIAEA Technical Workshop, AprilTechnical Workshop, April 2121--23, 23, MoscowMoscow

Numerical Modeling of Metal Local ErosionNumerical Modeling of Metal Local Erosion--Corrosion using Corrosion using RAMEKRAMEK--1 Software Complex1 Software Complex

NPPNPP Metal ErosionMetal Erosion--Corrosion Corrosion

One-(water) and two-phase (wet steam) flows

Water-chemistry

METAL

E/C

Hydro-thermodynamics

Corrosion

Erosion-Corrosion

Exposure time

Metal

Metal

Oxide

Oxide

Methodological Approach to EC Problem Solution at Methodological Approach to EC Problem Solution at NPPsNPPs

Investigation of physical and chemical EC processes and behavior

EC parameters and criteria

Data base

I stage

II stage

III stage

Software information-expertise complex

Complex of application software for NPP personnel support

RESOURCE CAPACITY FACTOR EFFICIENCY FACTOR

SG depositsOperating expenses for diagnostics

Forced outages and accidents

Operating expenses for preventive maintenance

Optimization of preventive maintenance work

Optimization of life extension methods for NPP secondary

circuit elements Optimization of EC diagnostics rules

EC calculation modelCalculation of residual life for NPP secondary circuit

elements

Operating state and EC activity maps of NPPsecondary circuit

EC operating monitoring at NPP

Monitoring of EC operating

characteristicsSample EC test-

module

NPP experience (inspection &

diagnostic methods)

Methods of NPPdamage inquiry

EC sc

ientifi

c res

earch

EC ev

aluati

on

and p

redict

ion

metho

ds

Norm

ative

do

cume

ntatio

n, pra

ctica

l so

lution

s

Tech

nical

& ec

onom

ical

result

s

Main Factors and Parameters of Main Factors and Parameters of NPPNPP Metal ErosionMetal Erosion--CorrosionCorrosion

�� Chemical compositionChemical composition of steelof steel % (% (Cr, Mo, CuCr, Mo, Cu).).�� Phase statePhase state of working environmentof working environment ((waterwater, ,

wet steamwet steam →→ moisture degreemoisture degree, %)., %).�� WaterWater--chemistry modechemistry mode ((рНрН local valueslocal values, , amineamine, ,

ОО22, , gas and impurities gas and impurities interphaseinterphase distribution factorsdistribution factors).).�� ThermoThermo--dynamics and physical properties of working environment dynamics and physical properties of working environment

((t, Pt, P, , ρρ,,, , ρρ,,,,,, νν,,, , νν,,,,, , σσ ……).).�� Average flow rateAverage flow rate..�� Exposure time Exposure time ((operationoperation).).

�� Channel geometryChannel geometry ((teetee, , bendbend, , narrowingnarrowing etc.etc.).).

�� Characteristics of channel with complex geometry Characteristics of channel with complex geometry ((flowing part profile).flowing part profile).�� Peculiarities of flow hydroPeculiarities of flow hydro--dynamicsdynamics::

-- local gradients of flow velocity local gradients of flow velocity dUxdUx((convection mechanism of mass transferconvection mechanism of mass transfer););

-- locallocal energy gradient of turbulent pulsations energy gradient of turbulent pulsations dKdK((vortex mechanism of mass transfer)vortex mechanism of mass transfer)..

++

GECGEC

LEC

LEC

dr

dr

Calculation Investigations of Carbon Steel Calculation Investigations of Carbon Steel ((StSt 20) 20) ErosionErosion--Corrosion Corrosion with with RAMEKRAMEK--2 Model2 Model

General Scheme of Local Area Identification and Wear (Thinning) General Scheme of Local Area Identification and Wear (Thinning) Activity Activity for Pipelines and Components Elements and Units for Pipelines and Components Elements and Units

of of NPPNPP CondensateCondensate--FeedwaterFeedwater CircuitCircuit

Pipeline units

Standard elements

GEC LEC

Cav yes CavE

no

no

yes

Preswitchedelements

pH values range of H2O liquid phase for different power units: I – NPPs with VVER-1000 (9.0+/- 0.2)II-French NPPs (9.2+/- 0.1)III-thermal electric plants, hydrazine mode (7.7+/- 0.2)IV-thermal electric plants, oxygen-ammonia mode (8.0+/- 0.5)

ammonia hydrazine morpholine ODAammonia 36 mkg/kg

Hydrazine 5 mkg/kg

Morpholine50 mkg/kgODA 30 mkg/kg

Calculation Calculation TopogramTopogram for Metal Erosionfor Metal Erosion--Corrosion Activity Corrosion Activity ((StSt20)20)of of 22RL74SO4RL74SO4 Regulator Bypass Inlet Bending and Connecting PipeRegulator Bypass Inlet Bending and Connecting Pipe by by RAMEKRAMEK--11

F low dir ection

Weld3 hours

bending

Connecting pipe

0 hours9 hours

6 hours

3 hours

mm/year

S, mm/year

Location of ErosionLocation of Erosion--Corrosion Damage at LP Heater Vessel Corrosion Damage at LP Heater Vessel №№6565and Numerical Modeling of Steam Flow Rate Vector Field and Numerical Modeling of Steam Flow Rate Vector Field at at

Smolensk Smolensk NPPNPP LP Heater Vessel InletLP Heater Vessel Inlet

W e t s t e a m

f l ow

Photo of damage atLP heater vessel N 65

Physical Picture of Deposit Area Generation and Liquid Film Physical Picture of Deposit Area Generation and Liquid Film TurbulizationTurbulization at the at the LPHLPH N65 Vessel Surface N65 Vessel Surface

of Smolensk of Smolensk RBMKRBMK--1000 Unit1000 UnitActive LEC area

Stagnation area

Max LEC area

Fusion areas of deposit and liquid film turbulization flowsLines of flow division

Conditions of active LEC implementation•Moisture degree >1.5-2.0%•Wet steam flows fusion and braking•Low velocity of wet steam flows W<=2,0-3,0 m/s (i.e. lack of breakaway and droplet moisture carry-over from liquid film surface)

Application of ErosionApplication of Erosion--Corrosion Calculation models Corrosion Calculation models ((RAMEKRAMEK) to Solve the Complex Program Tasks) to Solve the Complex Program Tasks

RAMEK

Identification of local areas with EC maximum activity in pipelines elements

Evaluation of metal EC activity based on modeling of physical-chemical processes considering EC

mechanisms

Metal EC prediction and evaluation of pipeline residual life

Optimization of preventive maintenance work

Implementation of erosion-corrosion monitoring at NPP

Review of guidelines, standard programs and instructions on inspection and management of NPP pipelines resource

Generation of controlled data base and maps of pipeline EC damageability

Optimization of inspection & diagnostics measures

for NPP personnel and specialized organizations

Identification of metal EC sensitivity of specific pipeline element to changing

different parameters and characteristics