Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant
New experimental data on the corrosion behavior of the 12X18H10T austenitic steel elastically strained cou-pons after 500 h long exposure in situ the NSC KIPT “Electron Irradiation Test Facility” supercritical water circulation loop are presented and discussed. The γ-activation analysis based comput...
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Bakai, O.S. Boriskin, V.M. Bratchenko, M.I. Dyuldya, S.V. 2023-12-07T10:53:03Z 2023-12-07T10:53:03Z 2022 Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant / O.S. Bakai, V.M. Boriskin, M.I. Bratchenko, S.V. Dyuldya // Problems of Atomic Science and Technology. — 2022. — № 1. — С. 55-63. — Бібліогр.: 12 назв. — англ. 1562-6016 PACS: 82.33.De;07.35.+k;29.20.Ej; 81.70.-q;61.82.Bg;81.65.Mq;68.37.-d;62.20.mt DOI: https://doi.org/10.46813/2022-137-055 https://nasplib.isofts.kiev.ua/handle/123456789/195828 New experimental data on the corrosion behavior of the 12X18H10T austenitic steel elastically strained cou-pons after 500 h long exposure in situ the NSC KIPT “Electron Irradiation Test Facility” supercritical water circulation loop are presented and discussed. The γ-activation analysis based computational dosimetry of samples is correlated to their weight gain/loss measurement data. The absorbed dose and stress effect on their irradiation assisted general corrosion is revealed. The corrosion surface/layer chemistry/microstructure are discussed with special emphasis of the irradiation/stress impact on the protective coating stability, intergranular corrosion and precursors of cracking. Наведені та обговорюються нові експериментальні дані щодо корозійної поведінки пружно деформованих купонів аустенітної сталі 12X18H10T після 500-годинної експозиції in situ надкритичної водної конвекційної петлі установки «Electron Irradiation Test Facility» ННЦ ХФТІ. Засновані на γ-активаційному аналізі дані обчислювальної дозиметрії зразків зіставлені з даними вимірів набуття або втрати їх маси. Виявлений вплив поглиненої дози та напруги на їх стимульовану опроміненням загальну корозію. Склад та мікроструктура корозійної поверхні та шару обговорюються з особливою увагою до впливу опромінення й напруги на стабільність захисного покриття, міжзеренну корозію та передвісники розтріскування. Приведены и обсуждаются новые экспериментальные данные по коррозионному поведению упруго-деформированных купонов аустенитной стали 12X18H10T после 500-часовой экспозиции in situ сверхкритической водной конвекционной петли установки «Electron Irradiation Test Facility» ННЦ ХФТИ. Основанные на γ-активационном анализе данные вычислительной дозиметрии образцов сопоставлены с данными измерений набора или потери ими массы. Выявлено влияние поглощенной дозы и напряжения на их стимулированную облучением общую коррозию. Состав и микроструктура коррозионной поверхности и слоя обсуждаются с особым вниманием к влиянию облучения и напряжения на стабильность защитного покрытия, межзеренную коррозию и предвестники растрескивания. This work was carried out at the expense of the budget program “Support for the Development of Priority Areas of Scientific Research” (КПКВК 6541230). en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Physics and technology of structural materials Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant Обчислювальна дозиметрія та післяопромінювальні дослідження стимульованих електронним опроміненням корозії та корозійного розтріскування під напругою статично деформованих зразків сталі в надкритичному водному теплоносії Вычислительная дозиметрия и послеоблучательные исследования стимулированных электронным облучением коррозии и коррозионного раскрошивания под напряжением статически деформированных образцов стали в сверхкритическом водном теплоносителе Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant |
| spellingShingle |
Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant Bakai, O.S. Boriskin, V.M. Bratchenko, M.I. Dyuldya, S.V. Physics and technology of structural materials |
| title_short |
Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant |
| title_full |
Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant |
| title_fullStr |
Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant |
| title_full_unstemmed |
Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant |
| title_sort |
computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant |
| author |
Bakai, O.S. Boriskin, V.M. Bratchenko, M.I. Dyuldya, S.V. |
| author_facet |
Bakai, O.S. Boriskin, V.M. Bratchenko, M.I. Dyuldya, S.V. |
| topic |
Physics and technology of structural materials |
| topic_facet |
Physics and technology of structural materials |
| publishDate |
2022 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Обчислювальна дозиметрія та післяопромінювальні дослідження стимульованих електронним опроміненням корозії та корозійного розтріскування під напругою статично деформованих зразків сталі в надкритичному водному теплоносії Вычислительная дозиметрия и послеоблучательные исследования стимулированных электронным облучением коррозии и коррозионного раскрошивания под напряжением статически деформированных образцов стали в сверхкритическом водном теплоносителе |
| description |
New experimental data on the corrosion behavior of the 12X18H10T austenitic steel elastically strained cou-pons after 500 h long exposure in situ the NSC KIPT “Electron Irradiation Test Facility” supercritical water circulation loop are presented and discussed. The γ-activation analysis based computational dosimetry of samples is correlated to their weight gain/loss measurement data. The absorbed dose and stress effect on their irradiation assisted general corrosion is revealed. The corrosion surface/layer chemistry/microstructure are discussed with special emphasis of the irradiation/stress impact on the protective coating stability, intergranular corrosion and precursors of cracking.
Наведені та обговорюються нові експериментальні дані щодо корозійної поведінки пружно деформованих купонів аустенітної сталі 12X18H10T після 500-годинної експозиції in situ надкритичної водної конвекційної петлі установки «Electron Irradiation Test Facility» ННЦ ХФТІ. Засновані на γ-активаційному аналізі дані обчислювальної дозиметрії зразків зіставлені з даними вимірів набуття або втрати їх маси. Виявлений вплив поглиненої дози та напруги на їх стимульовану опроміненням загальну корозію. Склад та мікроструктура корозійної поверхні та шару обговорюються з особливою увагою до впливу опромінення й напруги на стабільність захисного покриття, міжзеренну корозію та передвісники розтріскування.
Приведены и обсуждаются новые экспериментальные данные по коррозионному поведению упруго-деформированных купонов аустенитной стали 12X18H10T после 500-часовой экспозиции in situ сверхкритической водной конвекционной петли установки «Electron Irradiation Test Facility» ННЦ ХФТИ. Основанные на γ-активационном анализе данные вычислительной дозиметрии образцов сопоставлены с данными измерений набора или потери ими массы. Выявлено влияние поглощенной дозы и напряжения на их стимулированную облучением общую коррозию. Состав и микроструктура коррозионной поверхности и слоя обсуждаются с особым вниманием к влиянию облучения и напряжения на стабильность защитного покрытия, межзеренную коррозию и предвестники растрескивания.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/195828 |
| citation_txt |
Computational dosimetry and post-irradiation studies of the electron beam irradiation-assisted corrosion and stress corrosion cracking of statically strained steel samples in a supercritical water coolant / O.S. Bakai, V.M. Boriskin, M.I. Bratchenko, S.V. Dyuldya // Problems of Atomic Science and Technology. — 2022. — № 1. — С. 55-63. — Бібліогр.: 12 назв. — англ. |
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2025-11-24T15:54:12Z |
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ISSN 1562-6016. ВАНТ. 2022. №1(137) 55
https://doi.org/10.46813/2022-137-055
COMPUTATIONAL DOSIMETRY AND POST-IRRADIATION STUDIES
OF THE ELECTRON BEAM IRRADIATION ASSISTED CORROSION
AND STRESS CORROSION CRACKING OF STATICALLY STRAINED
STEEL SAMPLES IN A SUPERCRITICAL WATER COOLANT
O.S. Bakai, V.M. Boriskin, M.I. Bratchenko, S.V. Dyuldya
National Science Center “Kharkov Institute of Physics and Technology”, Kharkiv, Ukraine
E-mail: bakai@kipt.kharkov.ua
New experimental data on the corrosion behavior of the 12X18H10T austenitic steel elastically strained coupons
after 500 h long exposure in situ the NSC KIPT “Electron Irradiation Test Facility” supercritical water circulation
loop are presented and discussed. The -activation analysis based computational dosimetry of samples is correlated
to their weight gain/loss measurement data. The absorbed dose and stress effect on their irradiation assisted general
corrosion is revealed. The corrosion surface/layer chemistry/microstructure are discussed with special emphasis of
the irradiation/stress impact on the protective coating stability, intergranular corrosion and precursors of cracking.
PACS: 82.33.De;07.35.+k;29.20.Ej; 81.70.-q;61.82.Bg;81.65.Mq;68.37.-d;62.20.mt
INTRODUCTION
The Super-critical Water-Cooled Reactor (SCWR) is
the next Generation IV nuclear power reactor featuring
a water coolant in the state above the critical point
(Tc, Pc) = (374 °C, 22.1 MPa) of water. Supercritical
water (SCW) is a highly corrosive environment [1] for
the SCWR structural materials. The database of their
performance in SCW is systematically developing [2, 3]
but is far from completion having in mind complex in-
terplay of various driving forces of corrosion. Some of
them (water chemistry, pH and dissolved oxygen, tem-
perature) can be studied at out-of-pile autoclave tests.
The rest (coupled (n, )-irradiation, coolant flow and
radiolysis, thermal gradients and stress) are specific to
the reactor environment and are harder to understand
because of the lack and high costs of large-scale in-pile
tests. The laboratory simulation experiments at dedicat-
ed facilities are thus of great value to fill this gap in
knowledge of the SCWR relevant corrosion phenomena.
The NSC KIPT sited Electron Irradiation Test Fa-
cility (E.I.T.F.) contributed to this programme over the
past two decades. The core of the Facility is the LEA-10
electron linac (10 MeV/10 kWe). The E.I.T.F. features
several target assemblies and techniques for corrosion
tests under electron beam (EB) irradiation in situ high-
temperature molten salt and aqueous corrodents. For the
SCWR related tasks, the E.I.T.F. natural convection
principle based Super-Сritical Water Circulation Loop
(SCWCL, Fig. 1) was put into operation in 2012 [4].
The pilot (2012) experiment [4, 5] dealt with oxida-
tion and corrosion of high-purity Zr-1%Nb and Inco-
nel™ grade alloy 690 coupons irradiated in the vicinity
of the SCWCL coolant supercritical transition. Drastic
increase of the corrosion rate under irradiation (the phe-
nomenon of Irradiation Assisted Corrosion, IAC) was
first revealed for these alloys. Besides, severe Irradiati-
on Assisted Stress Corrosion Cracking (IASCC), crev-
ice corrosion, spallation and exfoliation were found in
the highly irradiated, overheated to 460 °C and embrit-
tled part of the austenitic stainless steel (SS) 12X1H10T
made Irradiation Cell (IC) piping of the facility [5].
Sporadic Inter-Granular SCC (IGSCC) was also obser-
ved in certain Inconel™ alloy coupons in the vicinity of
the base alloy 690 joint with the In52MSS weldup.
Fig. 1. The E.I.T.F. SCWCL ‘Loop1b’ mounted in the
LEA-10 linac shelter room. The photo had been taken
before the kick-start of the 2019 irradiation experiment
The phenomenological models were proposed [6] to
interpret quantitatively the observed effects by thorough
calculations and multi-scale computer simulation. Par-
ticularly, SCC was attributed to the impact of residual
and thermal-elastic stress. This motivated the main-
stream direction of further E.I.T.F./SCWCL R&D spe-
cifically focused on investigations of the mechanical
stress impact on materials corrosion under irradiation.
An appropriate upgrade of the SCWCL IC design
(see ref. 7) has resulted in the completion (2019) of
the next irradiation experiment specifically devoted to
the evaluation of IAC and IASCC of SS 12X18H10T
coupons in SCW under controlled static mechanical
load. In this paper, we report first results of the post-
irradiation analysis of the obtained irradiated specimens.
The paper is organized as follows. The experimental
setup, the material samples preparation and the e
–
-irradi-
mailto:bakai@kipt.kharkov.ua
56 ISSN 1562-6016. ВАНТ. 2022. №1(137)
ation mode details are described in Sec. 1. Novel me-
thod of the radiation field reconstruction and evaluation
of the samples obtained doses is presented in Sec. 2 and
applied, in Sec. 3.1, to uncover the regularities in their
post-irradiation General Corrosion Test (GCT) data.
The results of the corroded samples microstructure in-
vestigation are presented and discussed in Sec. 3.2.
1. EXPERIMENTAL
Twenty thin (280 m) rectilinear (409.6 mm)
coupons of the heatproof SS 12X18H10T (AISI 321),
Fe68Cr18Ni10Mn2Ti0.7Si0.8Cu0.3P0.035S0.02 wt.%, were placed
(5 per each) inside four 10 mm tubes IIV of the
E.I.T.F. SCWCL 4-channels IC [4–6], Fig. 2.
Fig. 2. The 4-channel IC before (a) and after (c) 500 h
long EB irradiation in the SCWCL. The coupons at-
tachment scheme is shown in (b, d)
Except of the coupons #22 and 23 which were cov-
ered with 9 m thick CrN coatings vacuum-arc depos-
ited from the BX1 Chromium alloy [8], all samples
were equal in dimensions and composition but substan-
tially differed in the intentionally applied static elastic
stress which sprung up from the strain produced by the
adjustter bolt imposed to a sample mid-span x = 0 (for
details, see ref. 7). Coupons of length l and thickness h
are freely edge-supported in the IC tube sample holding
cassette notches (Fig. 3). This results in a triangular
distribution of tensile stress xx(x)
=
max·(1 – 2·|x|
/
l)
[7], where max
=
6E·h·d
/
l
2
, E is the Young modulus,
and d is the bolt controlled maximal deflection. Accord-
ing to the IC loading plan of Fig. 2,b, different values of
d < 0.8 mm were used to spread max (60…140) MPa
of coupons in the SS elasticity domain below its ther-
mally reduced yield stress 0.2 = 174 MPa (400 °C).
In addition, to seek for the base stress discontinuity
effects, six (3 per side at x 0, ±10 mm) 80 m wide
10 m deep transversal scratches were diamond cutter
plotted on both convex (tensile stress xx > 0) and con-
cave (compressive xx < 0) surfaces of each coupon.
Fig. 3. The strained coupon mounted inside the IC
internal sample holder with the bend adjusting screw
Finite Element Method (FEM) calculations had pre-
dicted [7] the stress concentration at a scratch bottom
and close to its shoulders. It was found that the bottom
located highest stress scales well with the base one:
scratch kamp·xx(x), where kamp is the scratch shape de-
pendent amplification factor. The high-resolution opti-
cal metallography cross-section digitalization of the ge-
ometry of all the scratches on samples to be irradiated
was followed by a set of FEM calculations (Fig. 4). In
rather good agreement with the earlier [7] predicted
value of kamp 1.57, they resulted in kamp = 1.556±0.006
for the prepared set of specimens. Fig. 4 data show that
|scratch| augments to 220…240 MPa for middle scrat-
ches of the most strained coupons (see in Fig. 2,b, this
occurs for samples ##1, 4, 6, 9, 10, 15, 16, 19, 20, 22,
23), and, therefore, it is expected to exceed 0.2.
-150 -100 -50 0 50 100 150
-300
-200
-100
0
100
200
300
sc
ra
tc
h
(
M
P
a)
xx
(MPa)
scratch
=1.556 xx
FreeFEM++
Fig. 4. The FEM calculation based estimates of the ten-
sile/compressive stress concentration in the vicinity of
the scratches plotted on the investigated coupons:
the maximal scratch as a function of the base xx
The experiment was carried out in Aug.–Sep. 2019
and lasted 500 h of a scanning EB irradiation (in toto,
incl. transients, strained coupons were exposed to a cor-
rodent coolant for 532 h). The LEA-10 linac operated at
pulse duration 3.5 s, pulse frequency 250 Hz, mean
energy 10 MeV, mean current 0.71 mA and mean power
of 7.3 kWe. The linac scanning magnet (saw-tooth pul-
ses of scanning frequency 3.7 Hz) shaped the vertically
oblong (6
19) cm EB span on the SCWCL IC. The
total fluence of e-irradiation amounted to 2∙10
20
e
–
/cm
2
.
The per-day digital records of the linac and loop param-
eters were stored by the facility control system to serve
as raw data for further post-irradiation analysis (Fig. 5
for representative examples of these records).
c
d
a b
M
P
a
ϭxx, MPa
ISSN 1562-6016. ВАНТ. 2022. №1(137) 57
The deoxygenated distilled coolant was pressurized
to P = 23.5 MPa and freely circulated in the SCWCL
driven by thermal power Q inputs from both the bottom-
leg electrical heater and the EB power deposited in the
IC tubes and internals, incl. coupons. In the experiment
designing stage, System Thermal Hydraulics (STH) cal-
culations [7] assumed the reference natural circulation
scenario with Qheater = 1 kWth and Qbeam = 4 kWth owing
to 64% efficiency of the EB electric power utiliza-
tion to water heating in the IC. The coolant steady-state
mass-flow rate W 48 g/s has been predicted in ref. 7.
At actual irradiation schedule, the applied mean Qheater
was raised to 2.62 kWth while has been lowered down
to 55% cause of the lateral drift of the irradiation field
(see Fig. 2,d and below in Sec. 2). For such inputs, STH
calculations result in W = 54.3 g/s in a reasonable
(10%) agreement with the planned scenario.
Fig. 5. Per-day records of the EB mean energy (a),
electron fluence (a) and the vertical position and length
of the EB scanning area wrt. the SCWCL IC (b)
From the mass continuity considerations at the STH
predicted W, the water coolant speed v increases from
420 to 450 cm/s along a segment between the IC inlet
and outlet. However, for the samples loaded IC the open
hydraulic section area reduces and the characteristic
speed of coupons flow becomes about twice as large,
v 1 m/s, that is well comparable with the SCWR pri-
mary-coolant circuit SCW current velocity. This is con-
firmed by the Computational Fluid Dynamics (CFD) si-
mulations of the velocity field (see Fig. 9 of ref. 7)
which also made evident the twofold difference in v
near convex and concave sides of strained coupons.
In a steady-state circulation mode, the loop of the
nominal (at 20 °C) capacity of 3.81 L accommodated
2.45 kg of water of the turnover-averaged mean density
0.64 g/cm
3
. Coupled STH/Equation of State (EoS)
calculations point to lower = 0.58…0.54 g/cm
3
at a
coolant pass-through the IC. This is due to the EB indu-
ced heating and, mainly, the heat transfer from the hot-
test IC tubes and internals. The prescribed and the facili-
ty control system and operators sustained characteristic
temperature of the coolant circulation, Tin = 360 °C was
deliberately set smaller than both critical Tc = 374 °C
and pseudocritical Tpc(P) = 379.5 °C temperatures of
water. It was measured by an array of thermocouples
placed outside the irradiation zone (direct thermometry
is problematical inside it). The STH calculations reveal
the cross-section averaged temperature growth to
368 °C before the IC outlet, and the subsequent cooling.
The readings of the post-outlet thermocouples at the IC
outer surface were 364 °C for the IC channels II and III
(see Fig. 2,d) and 350 °C for tubes I and IV. By and
large, this agrees well with the STH prediction which
also well describes possible gradual cooling of a flow
by the end of weakly irradiated channels (see Fig. 9 of
ref. 6).
Generally, coolant circulated in a narrow lower vici-
nity of supercritical transition. However, under e
–
-irradi-
ation, the remote optical pyrometry measurements reve-
aled temperatures of 400420 °C >> Tpc at the air-
cooled external surface of the IC. In ref. 6, it was
shown that massive IC internals also can be about
10…15 K hotter then the STH predicted reference tem-
perature of a coolant. Thus, the supercritical transition
occurs just inside the IC in the vicinity of coupons, and
their corrosion phenomena are determined just by the
SCW flow.
The loop feedwater was of neutral pH = 7, 1.1 mg/L
of dissolved oxygen (DO), and conductivity 20 S/cm.
The coolant chemistry was routinely analyzed with the
WTW Multi 350i device at a batcher water sampling ra-
te 5 mL/min. Rather scattered values of (rather acidic)
pH (5.6
±
0.7) and DO (2.9
±
1.4) mg/L were detect-
ing. The conductivity grew systematically to 40 S/cm
and higher at a rate of 0.1 S/h. This argued for the
increase of ionic salts content. The coolant’s impurities,
dirt and crud were identified using the Shimadzu ICRP-
9000 optical emission spectrometer. The growth of (ini-
tially absent) Chromium content to 31 g/L at a rate of
0.2 g/L per hour was revealed just as it had been ob-
served in previous SCWCL runs [5]. Other elements
(Fe, Mn, K, Ni, S, Ca, Mg, Si, Ti, Cu) were also found
in discharged water samples. Evidently, this indicates an
intense pollution of a coolant with corrosion products of
both the same SS 12X18H10T made SCWCL internal
surface and the coupons under investigation.
2. COMPUTATIONAL DOSIMETRY
The E.I.T.F. experiment attempted to reproduce the
SCWR operation mode when a subcritical water coolant
experiences the repeated periodical transition to SCW
just inside the reactor core. The SCWCL IC serves as a
core ‘mock-up’. Its self-consistent description requires
extensive coupled irradiation dosimetry, radiolysis,
STH/CFD and FEM calculations [6] and is far beyond
the scope of the current paper. Here we address only the
first, dosimetry, step of this agenda’s roadmap.
Its goal is the consistent calculation of the absorbed
dose D (Gy = 100 rad) and primary radiation damage
Ndpa (in the number of displacements per atom, dpa) of
the investigated material on a per-coupon basis. The
complications arose from the uncertainty of the EB ra-
diation field on an IC. We attempted to obtain its recon-
struction using the computational dosimetry methods by
means of the GEANT4.10.6 Toolkit based Monte Carlo
(MC) radiation transport (RT) code RaT 3.1 which was
already used by us, for similar purposes, in refs. 4–6.
The experimental bases of the MC simulation efforts
were the preliminary glass photometry data (the conven-
tional method of the LEA-10 linac beam targeting befo-
re irradiation, Fig. 6) and their a posteriori refinement
wrt. the actual irradiation scenario based on the post-
irradiation measurements of the residual activity of irra-
diated coupons, the method we first propose here.
The RaT 3.1 code applied the G4EmStandard_opt3
model for simulation of electrons and bremsstrahlung
a b
58 ISSN 1562-6016. ВАНТ. 2022. №1(137)
-quanta transport in a realistic (Fig. 7) 3D model of the
coupons loaded IC target assembly, the processes
eRecoil and CoulombElastic for simulation of point de-
fect production in atomic collisions cascades, the LLNL
ENDF/B VII LEND nuclear data library for simulation
of the activation induced by electro- and protonuclear
reactions, the G4Radioactivation process to simulate the
activity decay with time, and the MC Variance Reducti-
on Technique (VRT) to force rare photonuclear events.
The GEANT4 G4FieldManager class was used to si-
mulate the LEA-10 linac scanning system (see Fig. 7)
for a routinely measuring EB energy spectrum having a
peak at 9.3 MeV, mean energy E = 10.27 MeV and a
long tail up to 17 MeV. The model took into account the
scanning horn geometry, the input pencil beam size of
Rbeam = 1 cm and its energy dependent angular divergen-
ce beam(E) = 25
(E
/
E)
2
mrad. The deflection of pri-
mary electrons by the magnetic field |Bx| 0.35 T was
sampled based on the pulse saw-tooth shape at a 3.7 Hz
scanning frequency. The EB scattering by the 40 m
thick linac output Titanium foil was simulated as well.
0 2 4 6 8 10 12 14 16 18 20 22
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
E
B
v
er
ti
ca
l
se
ct
io
n
(
re
l.
u
n
.)
z (cm)
experiment
simulation
x = 6.5 mm
-5 -4 -3 -2 -1 0 1 2 3 4
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
E
B
h
o
ri
zo
n
ta
l
se
ct
io
n
(
re
l.
u
n
.)
x (cm)
experiment
simulation
z = 12 cm
Fig. 6. The LEA-10 linac EB phase space preliminary
characterization based on the glass photometry data (a)
and its reproduction by the RaT 3.1 MC RT code: the
absorbed dose derived glass optical density map (b)
and its vertical (c) and horizontal (d) sections
In Fig. 6,a, it is clearly seen that the vertical sym-
metry axis of a beam scan is shifted, by xbeam, to the
left of that of the IC (see also Fig. 2,d). This allows to
decrease dose rates (and also -activation) in tubes I and
IV and to obtain an array of low-irradiated ‘witness’
samples.
The preliminary simulation (see Fig. 6,b–d) pointed
to xbeam 6.5 mm as a best fit of the (see Fig. 6,a) glass
photometry data. However, to characterize the most
probable irradiation field, required is not so much the
initial xbeam as its mean value averaged over the entire
500 h long irradiation session. To obtain it, we proposed
to use the results of activation analysis of all the cou-
pons. It was carried out about one month after the end of
irradiation session by means of the HPGe -spect-
rometer Canberra GC-2018 with fine energy resolution:
FWHM = 0.8 keV at Еγ = 122.1 keV, the most intensive
decay gamma line of the
57
Co radionuclide (half-life
T½ = 271.6 days) which is produced in SS via two chan-
nels of threshold (E Eth) photonuclear reactions: the
direct one,
58
Ni(, p)(Eth 8.2 MeV)
57
Co, and indirect
58
Ni(, n)(Eth 12.2 MeV)
57
Ni(T½ = 35.6 h)
57
Co.
Fig. 7. The computer models of the linac scanning horn,
irradiation cell and its loading with strained coupons
The raw data for coupons
57
Co partial activities were
obtained in units relative to that of the coupon IV3 (the
3
rd
one counting from the bottom of the tube IV) in a
series of about two-week separated measurements. In
Fig. 8, they are plotted (as ) after applying proper
timeshift corrections and a normalization to the utmost
values of coupons III2, 3. Other markers depict the
best fit output of MC modeling obtained in a series of
calculations with various xbeam the activation was found
to be very sensitive to. The best fit xbeam = 15 mm value
differs notably from the pre-irradiation glass photometry
estimate, 6.5 mm. This is probably due to both the EB
drift instabilities at the linac power control maneuvering
of the SCWCL coolant circulation and the thermal-elas-
tic distortion of the IC channels (see Fig. 2,c).
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5
0.0
0.2
0.4
0.6
0.8
1.0
1.2
tube IVtube IIItube II
5
7
C
o
a
ct
iv
it
y
(
re
l.
u
n
.)
Sample number (bottom-to-top)
tube I
x = 15 mm
experiment
EXFOR
Geant4 (LEND)
Fig. 8. The measured ()
57
Co relative activities of 20
irradiated coupons and their best fit reproduction by
the RaT 3.1 MC code modeling for xbeam = 15 mm.
Direct simulation of activation () and its validation
using the OECD EXFOR photonuclear data ()
c d
a b
x, cm
z, cm x, cm
ISSN 1562-6016. ВАНТ. 2022. №1(137) 59
The obtained optimal parameters of an experimental
irradiation field were applied to computational dosime-
try MC calculations resulted in the Fig. 9 data. The re-
quested variability of dosimetric quantities is clearly se-
en there. The irradiation load is gradually increasing in
the IC channels I to III. In the tube IV, it is marginal,
except of activation. Thus, the tube IV held coupons can
be regarded as ‘witness’ samples wrt. the irradiation im-
pact on corrosion. To a lesser extent, this also applies to
the topmost samples #5 of the generally highly irradia-
ted tubes I–III, where the energy spectra of electrons are
peaked at 6 MeV but still have long spectral tails up to
15 MeV. Only low (<
1 MeV) energy secondary Comp-
ton electrons are found in tube IV while the bremsstrah-
lung gamma flux remains significant there and is appar-
ent in considerable activation of ‘witness’ samples.
The well-conditioned linear D Ndpa cross cor-
relations are found in Fig. 9,b–d data. For a subsequent
analysis of corrosion responses, such correlations are
important to reduce the number of control variables [6].
Fig. 9. The MC simulation data on the per coupon
57
Co
activities A (a), electron fluences (b) absorbed doses
D (c) and the primary radiation damage dpa (d)
No linear correlation of the uncovered electron flu-
ence and absorbed dose D to the coupons’ activity A
was found. Instead, the scaling dependency D A
was
revealed (Fig. 10) with the scaling parameter 0.4 in
the EB irradiated tubes I–III and ½ for the second-
ary bremsstrahlung gammas activated tube IV.
0.01 0.1 1
0.1
1
10
D
A
0.5
tubes I, II
, III
A
b
so
rb
ed
d
o
se
D
(
G
G
y
)
57Co activity A (105 Bq)
tube IV
DA
0.4
Fig. 10. The revealed power law scaling dependencies
(dashed lines) of the absorbed dose D and -activation
activity A of the irradiated coupons (markers)
Dose D is determined by the EB energy deposition
in a target. It is the 1
st
order process since gamma heat-
ing is negligible wrt. the primary electrons one. In this
sense, -activation is the 2
nd
order process which is pre-
dominantly due to hard secondary photons born in the
1
st
order above-threshold bremsstrahlung events (the 1
st
order electronuclear reactions give only a small correc-
tion to the -flux induced photonuclear reactions rate
due to much smaller cross-sections). The relationship
between the 1
st
and 2
nd
order processes rates is complex
and spectrally dependent. Though a simple reason for
such a pronounced D A
scaling is still unclear, it
seems to follow from the specifics of the E.I.T.F. expe-
rimental setup where that same target, the IC, is operat-
ing both as the EB power absorber (D) and the e
–
-to-
converter for a self-consistent -activation (A) of its own
internals, coupons. The somewhat unexpectedly obtai-
ned computational dosimetry based rule-of-thumb, “the
dose in a sample is nearly proportional to the square
root of the induced activity”, is a valuable empirical
correlation which makes it possible to evaluate the ab-
sorbed dose distribution in irradiated coupons by means
of direct measurements of their residual activities.
In the upshot, it was revealed that the coupons were
irradiated to 7…22 GGy (0.7…2.2 Trad) at a rather low
(~ 6·10
–4
dpa) degree of their radiation damage. These
data are juxtaposed below with those of the post-irradia-
tion measurements of their corrosion and oxidation.
3. POST-IRRADIATION EXAMINATION
After completing the irradiation, coupons have been
extracted from the IC channels holders, photographed
(Fig. 11), and immediately weighed. All the strained
coupons have retained their structural integrity without
any kind of residual deformation. Thus, as predicted, the
base static stress under irradiation did not escape the
SS domain of elasticity.
Sample#
1 2 3 4 5
Fig. 11. Photos of the rear and front (wrt. the e
–
-beam)
sides of the SS 12X18H10T strained coupons after
500 h exposure to SCW under e
–
-irradiation.
The coolant flowed from left to right
Visually, all coupons look rusty and almost do not
differ in color. Scratches on both sides have not been
smoothed, albeit they are marked less clear than in the
initial state. On the rear, primarily concave, sides of the
samples, one can see the round spot traces of the presser
bolts and the parabolic trails of the waterflow past them.
It is very likely that the shapes of trails can provide data
on the flow speed in close proximity to the samples.
a b
d c
60 ISSN 1562-6016. ВАНТ. 2022. №1(137)
3.1. IRRADIATION ASSISTED CORROSION
The General Corrosion Test (GCT) data of Fig. 12
were obtained using the Class 2 (±0.025 mg) equal-arm
analytical laboratory balance VLR-20 by the thrice-re-
peated measurements of the specific (per unit area)
weight gain/loss (WG/WL) m/S = (m
–
m0)/S of each
coupon having masses m0 and m before and after irradi-
ation, respectively, and a surface area S of 7.154 cm
2
.
It was found that, in average, m0
=
(728.17
±
0.74) mg,
m
=
(728.35
±
0.76) mg except of the much heavier CrN
coated coupons III1 (m0
=
765.77 mg, m
=
731.22 mg)
and III4 (m0
=
764.86 mg, m
=
731.26 mg).
The GCT data of Fig. 12 look rather scattered in the
lump. First, let’s notice three conspicuous outliers.
Two of them concern the coated coupons III1, 4
which exhibit the extraordinary weight losses m/S of
–484 mg/dm
2
and –472 mg/dm
2
(m = –34.5 mg and
–33.6 mg), respectively. Their post-exposure masses m
(731.22 and 731.26 mg) are close to those of uncoated,
coupons, (728.35
±
0.76) mg. It suggests that all the
~ 10 m thick CrN coating was almost completely re-
moved (dissolved and/or broken and delaminated) under
co-operative impact of a coolant flow, e
–
-irradiation to
D
18 GGy, and static stress up to max
145 MPa.
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5
-490
-480
-470
-8
-6
-4
-2
0
2
4
6
8
50
55
60
m
/S
(
m
g
/d
m
2
)
Sample number
tube I tube II tube III tube IV
Fig. 12. The GCT measured specific weight gain (>0)
or loss (<0) m/S of the irradiated coupons
In surface engineering, CrN, though being prone to
aging, was proven to perform as a wear-proof rust-inhi-
biting coating not only in normal conditions but also in
SCW (625 °C, 25 MPa) 1000 h static autoclave test
[10]. However, its performance in the E.I.T.F. SCWCL
cannot be rated as any reasonable. It is questionable
whether this is due to a certain particular drawback of
the applied vacuum-arc deposition process or points to
this coating limited usability in the SCWR relevant en-
vironments. Extra R&D are definitely required.
An another outlier, the positive WG of 56.1 mg/dm
2
(m 4 mg) was measured for the poorly irradiated
(D
<
0.06 GGy) coupon IV–5, the topmost sample in the
‘witness’ channel IV of the IC. Its particular reason is
still unknown. Weight gains are generally attributed to
oxidation [1–3] and appearance of pronounced (flat or
rough) layers of oxides (as we observed earlier [5, 6] for
Zr and Ni–Cr based alloys as well as for a highly irradi-
ated thermally stressed SS 12X18H10T). However, at
T < 400 °C (see, e.g., [9, 11]), Fe–Cr austenitic steels ty-
pically show only thin volatile oxide layers and fre-
quently tend to the weight-loss corrosion kinetics [9].
The e
–
-irradiation enhanced oxidation suggests itself
as the most probable reason of the WG prevalence in the
Fig. 12 m/S data. Another one can be related to the
mass deposition from the corrosion products saturated
SCW coolant flow (including the CRUD [12] phenome-
non at the SCWCL transients). Thereupon it is worth
noting that the observed irregularities of the Fig. 13
m/S data mainly occur for the edge samples ##1, 5 of
the low-irradiated IC channels I and IV and are thus
expected to correlate with the specialties of the water
coolant hydrodynamics at the IC inlet and outlet.
Except of the above-mentioned outliers, the master
array of the Fig. 12 m/S data ranges from –3 mg/dm
2
to
8 mg/dm
2
(WG of this range and 0.25 m thin oxide
layers are characteristic for SS 304 and 316L at 575 h
exposure to 400 °C SCW deaerated to 10 ppb DO [11]).
These data exhibit certain empirical ordering trends wrt.
the sample number increase with the coupon’s inlet-to-
outlet position in the IC tube (see Fig. 11). They can be
qualitatively correlated to those of the STH calculated
coolant temperature [5–7] which is expected to increase
in the EB heated channels II and III and, probably in a
lesser extent, in tube I, but decreases in the ‘witness’
channel IV. The ‘main sequence’ coupons’ m/S gradu-
ally decreases with the sample number in the irradiated
channels I–III while shows an opposite growing trend in
a low-irradiated tube IV. Both these regularities can be
consolidated in the united trend of the GCT m/S de-
crease with the STH temperature of a coolant.
In average, m/S = +(2.58
±
0.78) mg/dm
2
for 17
coupons of the master array exposed, for 500 h, to the
SCWCL coolant (pH 5.6
±
0.7) under irradiation. This
is well comparable with the hydrostatic autoclave GCT
data [9] on the same SS at a close (but entirely subcriti-
cal) water environment, 350 °C, 16.5 MPa without irra-
diation. The authors of ref. 9 have built kinetic curves
of m/S gradual decrease for the much longer exposure
of 14000 h. The corrosion rate was shown to be drasti-
cally affected by the coolant pH (5.0, 7.2, and 10).
Opposite to Fig. 12, no weight gain was observed in
ref. 9. Despite, we ventured to compare the magnitude
|m/S| as an indicator of the corrosion damage driving
forces in both experiments. At a closest pH = 5, Fig. 1,a
of ref. 9 reports |m/S| 2.5 since 7500 h of expo-
sure (and it is only weakly changed till 14000 h). In the
same figure, this characteristic threshold time falls to
4000 h at pH = 7.2 and, at least, to well comparable
750 h at a highly alkaline pH = 10. One can conclude
that the effective corrosion rate is 15 to 8 times greater
in our experiment than in the static autoclave test [9] at
comparable pH’s without irradiation. The enhancement
can be attributed to the IAC phenomenon we had al-
ready observed [5, 6] for other materials. An auxiliary
gain also results from the impact of the coolant Flow
Accelerated Corrosion (FAC) [2] in the SCWCL.
The particular purpose of our current experiment is
the evaluation of the impact of the statically applied
stress on the material corrosion under irradiation. In
Fig. 13, the GCT master data array of m/S is plotted vs.
the calculated (in Sec. 2) values of the total ionization
ISSN 1562-6016. ВАНТ. 2022. №1(137) 61
dose D absorbed in coupons. We grouped these data by
the characteristic value max of their tensile stress.
Three lines of Fig. 13 indicate the trends discovered
in the stress grouped data using the linear Least-Square
Fit procedure. The linear dose D dependency of m/S is
evident for the low-stress (60 MPa) samples; the similar
(while less conditioned) one is found for the mediate
stress 100 MPa. The coupons which obey each of such a
linear correlation are located at the same level (3 or 2)
in different e
–
-irradiated tubes I–III; so, the coolant tem-
perature is nearly the same for each group. Therefore, at
sufficiently low stress, one observes here the isothermal
linear correlation of GCT data and absorbed dose.
0 5 10 15 20 25
-4
-2
0
2
4
6
8
IV-3
I-3
III-3
II-3
I-2
IV-2
II-2
III-2
I-4
II-1
I-1
II-4
I-5
II-5
IV-1
IV-5
III-1
III-5
IV-4
III-4
m
/S
(
m
g
/d
m
2
)
Absorbed dose D (GGy)
~60 MPa
~100 MPa
~140 MPa
Fig. 13. The measured GCT data for coupons with dif-
ferent ranks of the applied stress and absorbed dose
This correlation was first revealed, for Zr–1%Nb
and alloy 690 oxidation, in the ref. [6] phenomenologi-
cal data analysis of the previous E.I.T.F. experiment [5].
However, it is broken for a group of highly (~140 MPa)
stressed coupons. For this group, Fig. 13 m/S data scat-
ter and do not follow any smooth dose dependency. This
allows to make a conjecture that the applied static stress
produces its own effect on a general corrosion which…
(i) …extends further the well studied impact
of the IGSCC fracture [2, 3] and
(ii) …is comparable by magnitude with the ef-
fects of IAC and temperature.
It is still too early to make final judgments about the
specific nature of this effect of stress. However, sugges-
tive considerations can go after the analytical results on
the corroded samples microstructure we proceed to.
3.2. MICROSTRUCTURAL CHANGES
Scanning electron microscopy (SEM) imaging of
corrosion surfaces (CS, Fig. 14) and cross sections was
obtained using the JEOL JSM-7001F and ZEISS EVO-
50XVP microscopes with Oxford Instr. INCA-450
energy-dispersive spectroscopy (EDS) X-ray analyzer.
Up to date, 5 of 20 coupons from the IC channels II
and III were studied: the CrN coated samples ##22, 23
(III1, 4) and ordinary (uncoated) samples ##7, 9, 10
(II2, 4, 5) (for nomenclature, refer to Fig. 2,b and
Fig. 11).
Initially (see Fig. 14,a), the steel exhibits ~ 1 m
grains with boundaries decorated by < 0.1 m inclu-
sions, probably carbides and oxides since the EDS de-
rived chemistry points to 3 at.% of surface oxygen.
The rest is conformant to the SS 12X18H10T nominal
stoichiometry.
The post-irradiation micrographs of Fig. 14,b–d dis-
play a very developed ~ 1…2 m thick layer of oxidati-
on and corrosion damage. It looks extremely rough and
granular. The occasionally flat areas are scarce and lim-
ited, by size, to several microns. It is worth noting that
the representative 3000 SEM micrographs of the same
material’s CS after the 360 °C autoclave test (see [9],
Fig. 4) look similar but less disordered. Flat areas are
common in ref. 9 (esp. for pH = 5, 7.2) despite of the
much longer (14000 h) exposure time. This agrees with
the enhanced IAC in much harder conditions of the
coupons’ oxidation and corrosion in the SCWCL IC.
Fig. 14. SEM (5000, 1 m scale bar) of a steel in an
initial state (a), the post-irradiation 4000 SEM 3D
view of the sample II2 slice (b) and the samples
II4 (c) and II5 (d) corrosion surfaces (5000,
1 m bar)
The SEM/EDS evaluated CS chemistry points to
45 at.% of oxygen and identifies the depletion of Cr
(down to 10 at.% cf. the initial 18.6 at.%),
Ni (9 6 at.%) and Fe (67 38 at.%). The deposit-
like columnar CS morphology consists of ~ 0.2…2 m
sized and frequently faceted grains, flakes and granules
of metal oxides (magnetite, hematite, spinel and corun-
dum-type structures) along with ferric oxyhydroxides
FeO(OH) and carbides. This is peculiar to high-
temperature oxidation of austenitic Fe–Cr alloys in
SCW [2, 3, 11] and is close to that observed at the earli-
er E.I.T.F. experiment [5].
Fig. 15. SEM of the initially coated sample III1: the
2500, 10 m scale bar CS overview (a) and the high-
resolution (10000, 1 m bar) micrograph of a pit (b)
The characteristic post-irradiation morphology of the
a b
c d
a b
Absorbed dose D, GGy
62 ISSN 1562-6016. ВАНТ. 2022. №1(137)
CrN coating is shown in Fig. 15. Generally, it looks as
random as that of uncoated coupons (see Fig. 14,c,d) but
is less covered with smaller particles. Flat regions are
larger. Besides, the apparent pitting (see Fig. 15,b) of a
CS results in clearly outlined ~ 1 m deep pits occasion-
ally filled with small (< 0.2 m) granules. The CS is
only slightly less (38 at.%) oxidized than that of un-
coated coupons but shows the substantial (9 at.%) con-
tent of nitrogen. On the X-ray EDS maps, it is spatially
localized in agglomerates (the same is valid for oxygen)
and in elongated ‘strips’. This allows to identify the
agglomerated particles as the oxynitrides MeOxNy of
metals (Cr, Ni, Fe) and confirms the Sec. 3.1 GCT data
based conclusion that we deal only with the residues of
the initial-ly dense thick (9 m) coating of Cr–N stoi-
chiometry.
Fig. 16. The post-irradiation x-sectional SEM of the
coupon’s II2 convex frontal surface middle scratch
Corrosion effects of the elastic tensile stress concen-
tration on scratches were examined for the 16.3 GGy ir-
radiated and strained to 105 MPa coupon II2 with a ra-
ther high WG = +6.16 mg/dm
2
. The stress-raiser scratch
is shown in low (800) magnification in Fig. 16. It is
covered by the ~1…3 m thick rough layer of oxides
which is notably thinner on the scratch shoulders. The
CS morphology outside the scratch and near its bottom
(where the raised tensile stress xx 177.5 MPa 0.2,
see Fig. 4) is presented in Fig. 17, respectively.
Fig. 17. The coupon II2 CS SEM (5000, 1 m scale
bar) 150 m away from the scratch (a) and inside it (b)
The equal-area CS morphologies of Fig. 17 are gen-
erally similar by structure (<
1 m sized particles) and
chemistry (large grains are mainly of hematite Fe2O3).
However, about twofold as large (~ 2 m) particles are
observed more frequently near the scratch bottom. It can
result from the stress enhanced intergranular oxidation
and etching of grain boundaries followed by chemical
transformation of etched grains into ferric oxide granu-
les. An intergranular corrosion and sporadic appearance
of the stress promoted crack nucleation are seen in
Fig. 18. The characteristic distance between the oxygen
decorated grain boundaries in Fig. 18,b is nearly the
same as the size of largest particles in Fig. 17,b.
Fig. 18. The compositional contrast (COMPO, 8000,
1 m scale bar) SEM of the scratch shoulder (a) and
bottom (b) with the traces of intergranular oxidation (b)
and crack nucleation (a) at stress risers
Here we observe only a weak tendency of a material
to IGSCC by the stress enhanced crack nucleation (see
Fig. 18,a) while much more pronounced SCC precursors
had been revealed in ref. 5 for the same material in
more severe conditions of crevice corrosion, higher
temperatures and differently distributed mechanical
loading. To study the material tolerance to the IASCC
within the currently developed controllable technique,
supplementary factors are appropriate, e.g., the simula-
tion of fatigue effects through the in situ application of
cyclic mechanical treatment. The works are in progress.
ACKNOWLEDGEMENTS
This work was carried out at the expense of the
budget program “Support for the Development of Pri-
ority Areas of Scientific Research” (КПКВК 6541230).
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Article received 21.10.2021
ВЫЧИСЛИТЕЛЬНАЯ ДОЗИМЕТРИЯ И ПОСЛЕОБЛУЧАТЕЛЬНЫЕ ИССЛЕДОВАНИЯ
СТИМУЛИРОВАННЫХ ЭЛЕКТРОННЫМ ОБЛУЧЕНИЕМ КОРРОЗИИ
И КОРРОЗИОННОГО РАСТРЕСКИВАНИЯ ПОД НАПРЯЖЕНИЕМ
СТАТИЧЕСКИ ДЕФОРМИРОВАННЫХ ОБРАЗЦОВ СТАЛИ
В СВЕРХКРИТИЧЕСКОМ ВОДНОМ ТЕПЛОНОСИТЕЛЕ
А.С. Бакай, В.Н. Борискин, М.И. Братченко, С.В. Дюльдя
Приведены и обсуждаются новые экспериментальные данные по коррозионному поведению упруго-
деформированных купонов аустенитной стали 12X18H10T после 500-часовой экспозиции in situ сверхкри-
тической водной конвекционной петли установки «Electron Irradiation Test Facility» ННЦ ХФТИ. Основан-
ные на -активационном анализе данные вычислительной дозиметрии образцов сопоставлены с данными
измерений набора или потери ими массы. Выявлено влияние поглощенной дозы и напряжения на их стиму-
лированную облучением общую коррозию. Состав и микроструктура коррозионной поверхности и слоя об-
суждаются с особым вниманием к влиянию облучения и напряжения на стабильность защитного покрытия,
межзеренную коррозию и предвестники растрескивания.
ОБЧИСЛЮВАЛЬНА ДОЗИМЕТРІЯ ТА ПІСЛЯОПРОМІНЮВАЛЬНІ ДОСЛІДЖЕННЯ
СТИМУЛЬОВАНИХ ЕЛЕКТРОННИМ ОПРОМІНЕННЯМ КОРОЗІЇ ТА КОРОЗІЙНОГО
РОЗТРІСКУВАННЯ ПІД НАПРУГОЮ СТАТИЧНО ДЕФОРМОВАНИХ ЗРАЗКІВ СТАЛІ
В НАДКРИТИЧНОМУ ВОДНОМУ ТЕПЛОНОСІЇ
О.С. Бакай, В.М. Борискін, М.І. Братченко, С.В. Дюльдя
Наведені та обговорюються нові експериментальні дані щодо корозійної поведінки пружно деформова-
них купонів аустенітної сталі 12X18H10T після 500-годинної експозиції in situ надкритичної водної конвек-
ційної петлі установки «Electron Irradiation Test Facility» ННЦ ХФТІ. Засновані на -активаційному аналізі
дані обчислювальної дозиметрії зразків зіставлені з даними вимірів набуття або втрати їх маси. Виявлений
вплив поглиненої дози та напруги на їх стимульовану опроміненням загальну корозію. Склад та мікрострук-
тура корозійної поверхні та шару обговорюються з особливою увагою до впливу опромінення й напруги на
стабільність захисного покриття, міжзеренну корозію та передвісники розтріскування.
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