This document summarizes analytical and experimental studies conducted for the development of a core catcher to contain molten core materials in the event of a severe nuclear accident. It describes severe accident analysis, management procedures, and the application of a core catcher. It then summarizes international projects on severe accident measures and development. The document outlines studies on melt stratification and distribution between layers under inert atmosphere. It also describes experiments on control rod materials effects and interactions. Finally, it provides details on the design of a core catcher for a specific nuclear reactor and lists several patents related to core catcher designs and sacrificial materials.

1. Analytical and Experimental StudiesAnalytical and Experimental Studies
for Core Catcherfor Core Catcher DevelopmentDevelopment
Yu. Zvonarev
NRC “Kurchatov Institute”
Seminar with Vietnamese experts
Moscow, NRC “Kurchatov Institute”, December 9, 2013

2. 22
The Safety ConceptThe Safety Concept
• Severe accident analysis
• Severe accident management
• Core catcher application

3. 33
ScientificScientific BackgroundBackground
of Severe Accident Measures Procedures Development:of Severe Accident Measures Procedures Development:
RASPLAV (1994-2000) and MASCA (2000-2006) OECD Projects
List of participants:
The Association Vincotte Nuclear, jointly with Tractebel S.A., Belgium
The Atomic Energy of Canada Limited, Canada
The Fortum Nuclear Services Ltd, jointly with Valtion Teknillinen
Tutkimuskeskus and Säteilyturvakeskus, Finland
The Institut de Radioprotection et de Sûreté Nucléaire, France
The Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH, Germany
The KFKI Atomic Energy Research Institute, Hungary
The Nuclear Power Engineering Corporation, Japan
The Korea Atomic Energy Research Institute, Korea
The Nuclear Regulatory Authority of the Slovac Republic, Slovakia
The Consejo de Seguridad Nuclear, Spain
The Statens Kärnkraftinspektion, Sweden
The Paul Scherrer Institute, Switzerland
The United States Nuclear Regulatory Commission, USA
The Russian Federation Ministry of Atomic Energy, jointly with the
Federal Nuclear and Radiation Safety Authority of Russia, and the
National Research Centre «Kurchatov Institute», Russia

4. 44
Study of Melt Stratification and Distribution of Major
Species (U , Zr, O, Fe(SS)) between layers in Inert
Atmosphere at Large Iron (SS) to Corium Ratio
Test conditions:
 Inert atmosphere
 Two basic corium compositions: C-32
and C-70 with U/Zr = 1.2 and U/Zr=0.9
 Small scale STFM facility with the loaded mass about 0.5 kg;
 Middle scale RASPLAV-3 facility with the loaded mass of
about 2 kg;
Objective:
To obtain quantitative and qualitative characteristics of uranium,
zirconium and steel components partitioning between different phases.
Activity:
 Technology development;
 Facility modernization;
 Test preparation and performance;
 Post-test examinations.
STFM
RASPLAV-3
Facilities:

5. 55
Study of Control Rod Materials Effects
on Interaction and Distribution of Major Species
(U , Zr, O, Fe(SS)) in Inert Atmosphere
 The effects of the following absorbing materials are studied:
 Boron carbide (Matrix 2.1), silver-indium-cadmium (Matrix 2.2) and boron
oxide(Matrix 2.3)
Objective: to extend the thermodynamic database including additional structural
materials
 Test conditions
 Inert atmosphere
 Two basic corium compositions: C-32 and C-70 with FP simulants in some
tests
 U/Zrratio=1.2
STFM-B KORPUS-M

6. 66
RASPLAV ProjectRASPLAV Project
Major Objective: Extend knowledge base to determine specific
features of prototypic corium molten pool
Scope of Work: Separate effect corium tests, Material properties,
Supporting salt tests, Confirmatory large-scale integral
tests, Code development
RASPLAV-AW-200
Test Matrix
RASPLAV-AW-200
Facility
AW-1 AW-2 AW-3 AW-4
Corium composition C-22 C-22 C-100 C-32
Corium loading 198 kg 198 kg 195 kg 200 kg
Peak heat flux to the
test wall
130 kW/m2 280
kW/m2 90 kW/m2
180 kW/m2
Molten volume 70% 72% 60% 76%
Specific features
Stratification of the
melt into two
immiscible layers
Additives:
FeO: 2.4 kg
La2O3: 3.5 kg
No carbon

7. 77
The MASCA Project Findings
Low iron to corium ratio
Low corium oxidation degree
High iron to corium ratio
High corium oxidation degree
Low iron to corium ratio
Medium corium oxidation
degree
Molten steel extracts some metallic uranium
and zirconium from sub-oxidized corium
ρmet> ρoxide ρmet~ ρoxide ρmet< ρoxide
OxideOxide
Metal bodyMetal body
OxideOxide
Metal bodyMetal body
OxideOxide
Metal bodyMetal body

8. Core Catcher Basic Functions
• Localization into the core catcher vessel of liquid and solid
components of the corium, fragments of the core and reactor
structural materials;
• The transfer of heat from the corium to the cooling water and
the guaranteed cooling of the corium melt;
• Providing subcritical state of the corium;
• Prevention of steam explosion;
• Minimizing of fission products release from corium into
containment;
• Minimizing of hydrogen generation.
88

9. 99
Main Technical Decisions
for Core Catcher Development
• The choice of "crucible" type of core catcher design for
melt localization and cooling by water;
• The application of double-layer wall for core catcher
vessel to prevent its destruction due to thermal stress;
• The use of sacrificial materials from iron oxide and
aluminum oxide to reduce:
- the molten corium temperature and the volume density of
decay heat release
- minimizing of fission products release from corium;
- minimizing of hydrogen generation;
• Adding to the sacrificial materials a gadolinium oxide to
provide subcritical state of the corium.

10. Design of the Core Catcher for VVER-1200Design of the Core Catcher for VVER-1200
1 ‑ reactor vessel ; 2 ‑ bottom plate; 3 ‑ console truss; 4 ‑ technological corridor;
5 ‑ core catcher vessel; 6 ‑ reactor cavity; 7‑11 - cassettes with sacrificial materials;
12 ‑ thermal protection; 13 – service platform; 14 ‑ ventilating corridor.

11. 1111
Core Catcher Vessel FilledCore Catcher Vessel Filled
by the Cassettes with Sacrificial Materialsby the Cassettes with Sacrificial Materials

12. 1212
Core Catcher Cassette with Sacrificial MaterialsCore Catcher Cassette with Sacrificial Materials
(4-th Layer)(4-th Layer)

13. 1313
 Sacrificial material brick in the form of a triangular prism
 Sacrificial material composition:
Fe2O3 (65-70%), Al2O3 (28-30%), Gd2O3 (≥0.15%), SiO2 ≤ 7%
 Manufacturing technology:
 dosage;
 mixing;
 pressing;
 sintering.
Appearance of theAppearance of the Brick of a Sacrificial MaterialBrick of a Sacrificial Material
213
50

14. 1414
Sacrificial Material SelectionSacrificial Material Selection
 Stage 1: Preliminary selection of oxidic material
 Stage 2: Experimental examination of corium and sacrificial
materials phase properties
 Stage 3: Experimental study of corium Interactions with
sacrificial materials
Main Stages of Work

15. 1515
Sacrificial Material SelectionSacrificial Material Selection
Stage 1: Preliminary Selection of Oxidic Material
Basic Properties of Considered Oxides
Oxide
Density
(g/cm3
)
Melting
temperature
(о
C)
Boiling
temperature
(о
С)
Melting
heat
(kJ/kg)
Heat
capacity at
300 K
(kJ/(g·K))
Heat
conductivity
at 300 K
(W/(m·K))
α-Al2O3 3.97 2046 3696 1108 0.775 25
B2O3 1.84 450 2074 353 0.902 -
BаO 5.72 1923 3050 376 0.306 -
CaO 3.37 2777 3632 1344 0.749 15
Cr2O3 5.21 2234 3051 689 0.843 -
(FeO)*
5.7 1374 3079 437 0.695 -
Fe3O4 5.18 1597 decomposed - 0.651 ~5
Fe2O3 5.25 1457 decomposed - 0.650 ~5
MgO 3.58 2825 3115 1921 0.923 36
Nb2O5 4.95 1490 3397 389 0.497 -
α-SiO2 2.65 1610 2857 186 0.969 1.0
α-TiO2 3.84 1868 2927 838 0.690 6.53
V2O5 3.36 680 2052 358 0.703 4.4
Y2O3 4.84 2430 4027 372 0.454 6.28
Analyzed reference properties of the selected materials taking into account functional
requirements (including cost) allowed to reduce this list and to choose as the main
sacrificial materials (SM) Fe2O3 and Al2O3.

16. 1616
Sacrificial Material SelectionSacrificial Material Selection
Objectives:
• Evaluation of SM compositions with lowest solidus temperatures.
• Estimation of gas release.
• Assessment of minimum oxide density to provide corium layers inversion
(oxide layer – the upper one).
Experimental program:
• Two facilities in Russia : STF (NRC KI) and RASPLAV-2 (NITI).
• Induction heating of W acceptor, radiation heating of the sample.
• Specimens with corium C-30, C-100 and different composition of Fe2O3 +
Al2O3 + SiO2+ Cr2O3 sacrifice material (SM).
• Temperature measurements of sample melting (liquidus) and corium
spreading.
• Gas release measurements.
• 36 experiments were performed in NRC KI and NITI.
Stage 2: Experimental Examination of Corium + SM
Phase Properties

17. 1717
Sacrificial Material SelectionSacrificial Material Selection
Objectives:
• Measurement of interaction rate.
• Detection of potential oxygen release.
• Assessment of optimal Fe2O3 content.
Experimental program:
• Two facilities in Russia : KORPUS (NRC KI) and RASPLAV-2 (NITI).
• Induction heating in cold crucible.
• Specimens with corium C-32, C-100 and different composition of Fe2O3 +
Al2O3 + concrete + Gr2O3 sacrifice material (SM).
• 7 experiments were performed in NRC KI and NITI.
Stage 3: Experimental Study of Corium
Interactions with Sacrificial Materials

18. 1818
Sacrificial Material SelectionSacrificial Material Selection
1. Equimolar compound allows effective binding of active Zr in corium.
2. Decrease of hematite content from 100% led to excluding of potentially
dangerous release of free oxygen.
3. Application of Fe2O3 + Al2O3 compound excluded the recovery of
Al2O3 and subsequent gas release of highly volatile AlO2 from corium.
4. Experiments confirmed low melting temperatures during eutectic
interaction between corium and sacrificial material.
5. Mutual dissolution of corium and sacrificial material can be realized
with high rates, sufficient for effective corium temperature decrease.
6. Theoretical and experimental examinations allowed to recommend the
following composition for sacrificial material:
Fe2O3 (65-70%), Al2O3 (28-30%), Gd2O3 (≥0.15%), SiO2 ≤ 7%
Results

19. List of Patents on Core Catcher DesignList of Patents on Core Catcher Design
and Sacrificial Materialand Sacrificial Material
1. Gusarov V.V., Khabensky V.B., Bechta S.V., Granovsky V.S., Almjashev V.I.,
Krushinov E.V., Vitol S.A., Sergeev E.D., Petrov V.V., Tikhomirov V.A., Migal V.P.,
Mozherin V.A., Sakulin V.Ya., Novikov A.N., Salagina G.N., Shtern E.A. Oxide
material for a molten-core catcher of a nuclear reactor // China Patent ZL
02807587.0. Published July 13 2005.
2. Хабенский В.Б., Грановский В.С., Бешта С.В., Сидоров А.С., Носенко Г.Е.,
Клейменова Г.И., Сергеев Е.Д., Тихомиров В.А., Петров В.В., Замятин О.Н.,
Нечаев А.К., Онуфриенко С.В., Кухтевич И.В., Безлепкин В.В., Гусаров В.В.,
Беркович В.М., Клоницкий М.Л., Копытов И.И. Система локализации и
охлаждения кориума аварийного ядерного реактора водо-водяного типа //
Патент РФ № 2253914. Приоритет от 18.08.2003. Дата публикации –
27.02.2005.
3. Павлова Е.А., Сидоров А.С., Соловейчик Э.Я., Тихомиров В.А., Удалов Ю.П.,
Федоров Н.Ф. Керамический материал для ловушки расплава активной зоны
атомного реактора // Евразийский патент № 003961, Дата публикации:
30.10.2003.
4. Бешта С.В., Витоль С.А., Миселев В.М., Павлова Е.А., Сидоров А.С., Судакас
Л.Г., Удалов Ю.П., Федоров Н.Ф., Хабенский В.Б. Бетон для ловушки расплава
активной зоны атомного реактора // Патент РФ № 2214980, Дата публикации:
27.10.2003.
5. Бешта С.В., Витоль С.А., Миселев В.М., Павлова Е.А., Сидоров А.С., Судакас
Л.Г., Удалов Ю.П., Федоров Н.Ф., Хабенский В.Б. Цемент для ловушки
расплава активной зоны атомного реактора // Патент РФ № 2215340,
Дата публикации: 27.10.2003.
6. Gusarov V.V., Khabensky V.B., Beshta S.V., Granovsky V.S., Almyashev V.I.,
Krushinov E.V., Vitol S.A., Sergeev E.D., Petrov V.V., Tikhomirov V.A., Migal V.P.,
Mozherin V.A., Sakulin V.Ya., Novikov A.N., Salagina G.N., Shtern E.A. Oxide
material for a molten-core catcher of a nuclear reactor // PCT patent WO
03/032326. Priority Apr. 2, 2002. Patented Apr. 17, 2003.
7. Gusarov V.V., Khabensky V.B., Beshta S.V., Granovsky V.S., Almyashev V.I.,
Krushinov E.V., Vitol S.A., Sergeev E.D., Petrov V.V., Tikhomirov V.A., Migal V.P.,
Mozherin V.A., Sakulin V.Ya., Novikov A.N., Salagina G.N., Shtern E.A. Oxide
material for a molten-core catcher of a nuclear reactor // PCT patent WO
03/032325. Priority Apr. 2, 2002. Patented Apr. 17, 2003.
8. Гусаров В.В., Альмяшев В.И., Столярова В.Л., Хабенский В.Б., Бешта С.В.,
Грановский В.С., Анискевич Ю.Н., Крушинов Е.В., Витоль С.А., Саенко И.В.,
Сергеев Е.Д., Петров В.В., Тихомиров В.А., Мигаль В.П., Можжерин В.А.,
Сакулин В.Я., Новиков А.Н., Салагина Г.Н., Штерн Е.А. Оксидный материал
ловушки расплава активной зоны ядерного реактора // Патент РФ № 2212719.
Приоритет от 12.10.2001. Дата публикации – 20.06.2003.
9. Гусаров В.В., Альмяшев В.И., Саенко И.В., Бешта С.В., Грановский В.С.,
Хабенский В.Б., Мигаль В.П., Можжерин В.А., Сакулин В.Я., Новиков А.Н.,
Салагина Г.Н., Штерн Е.А. Способ получения керамических материалов для
ловушки расплава активной зоны ядерного реактора, содержащих оксиды
железа, алюминия и диоксид кремния // Патент РФ № 2206930. Приоритет от
02.04.2002. Дата публикации – 20.06.2003.
10. Gusarov V.V., Khabensky V.B., Beshta S.V., Granovsky V.S., Almyashev V.I.,
Krushinov E.V., Vitol S.A., Sergeev E.D., Petrov V.V., Tikhomirov V.A., Bezlepkin
V.V., Kukhtevich I.V., Aniskevich Yu.N., Sayenko I.V., Stolyarova V.L., Migal V.P.,
Mozherin V.A., Sakulin V.Ya., Novikov A.N., Salagina G.N., Shtern E.A., Asmolov
V.G., Abalin S.S., Degaltzev Yu.G., Zagryazkin V.N. Oxide material for a molten-
core catcher of a nuclear reactor // PCT patent WO 02/080188. Priority Apr. 2,
2002. Patented Nov. 21, 2002.
11. Гусаров В.В., Альмяшев В.И., Столярова В.Л., Хабенский В.Б., Бешта С.В.,
Грановский В.С., Анискевич Ю.Н., Крушинов Е.В., Витоль С.А., Саенко И.В.,
Сергеев Е.Д., Петров В.В., Тихомиров В.А., Мигаль В.П., Можжерин В.А.,
Сакулин В.Я., Новиков А.Н., Салагина Г.Н., Штерн Е.А. Оксидный материал
ловушки расплава активной зоны ядерного реактора // Патент РФ № 2192053.
Приоритет от 12.10.2001. Дата публикации – 27.10.2002.
12. Гусаров В.В., Альмяшев В.И., Столярова В.Л., Хабенский В.Б., Бешта С.В.,
Грановский В.С., Анискевич Ю.Н., Крушинов Е.В., Витоль С.А., Саенко И.В.,
Сергеев Е.Д., Петров В.В., Тихомиров В.А., Мигаль В.П., Можжерин В.А.,
Сакулин В.Я., Новиков А.Н., Салагина Г.Н., Штерн Е.А. Оксидный материал
ловушки расплава активной зоны ядерного реактора // Патент РФ № 2191436.
Приоритет от 12.10.2001. Дата публикации – 20.10.2002.
13. Gusarov V.V., Khabensky V.B., Beshta S.V., Granovsky V.S., Almyashev V.I.,
Krushinov E.V., Vitol S.A., Sergeev E.D., Petrov V.V., Tikhomirov V.A., Bezlepkin
V.V., Kukhtevich I.V., Aniskevich Yu.N., Sayenko I.V., Stolyarova V.L., Migal V.P.,
Mozherin V.A., Sakulin V.Ya., Novikov A.N., Salagina G.N., Shtern E.A., Asmolov
V.G., Abalin S.S., Degaltzev Yu.G., Zagryazkin V.N. Oxide material for a molten-
core catcher of a nuclear reactor // PCT patent WO 02/080188. Priority Apr. 2,
2002. Patented Nov. 21, 2002.
14. Гусаров В.В., Бешта С.В., Хабенский В.Б., Грановский В.С., Саенко И.В.,
Безлепкин В.В., Кухтевич И.В., Можжерин В.А., Мигаль В.П., Сакулин В.Я.,
Новиков А.Н., Салагина Г.Н., Штерн Е.А. Шихта для получения материала,
обеспечивающего локализацию расплава активной зоны ядерных реакторов //
Патент РФ № 2178924. Приоритет от 02.04.2001. Дата публикации –
27.01.2002.
15. Силин В.А.; Вознесенский В.А.; Малышенко С.П.; Митькин В.В.; Осадчий А.И.;
Пономарев-Степной Н.Н.; Столяревский А.Я. Устройство для улавливания
расплавленных материалов из ядерного реактора // Патент № 2164043,
Дата подачи заявки: 04.08.1999, Дата публикации: 10.03.2001.
16. Сидоров А.С., Носенко Г.Е., Розенберг Ю.С., Максимов Ю.Н., Рогов М.Ф.,
Логвинов С.А. Ловушка активной зоны ядерного реактора // Патент №
2100854. Патентообладатель: «ОКБ Гидропресс».

20. 2020
 2-D axial symmetric conductivity
 Volumetric heat decay
 Melting of the sacrificial material and mixing with the corium
 Thermal ablation of the concrete
 Chemical reactions between the sacrificial materials and the corium
 Molten pool formation and stratification
 Convective heat transfer between the layers of the molten materials
 Crust formation
 Radiation heat transfer from the upper surface of the molten pull
 External water cooling of the core catcher vessel
HEFEST-ULR CodeHEFEST-ULR Code
Modeled thermal physics and physical chemical processes:

21. 2121
Modeled processesModeled processes:: chemical reactionschemical reactions
On the melt front:
Zr oxidation:
Zr + 2H2O = ZrO2 + 2H2 + Q
Fe2O3 + 1.5Zr = 2Fe + 1.5ZrO2 + Q
Cr and Ni oxidation:
Сr + 1.5H2O = 0.5Сr2O3 + 1.5H2 + Q
Ni + H2O = NiO + H2 + Q
Fe2O3 + 2Cr = 2Fe + Cr2O3 + Q
Fe2O3 + Ni = 2FeO + NiO + Q
Hematite restoration:
Fe2O3 = 2FeO + 0.5O2 – Q
Fe oxidation:
Fe + 0.5O2 = FeO + Q
Fe + H2O = FeO + H2 + Q
In the molten pool volume:
Zr oxidation:
FeO + 0.5 Zr = Fe + 0.5ZrO2 +Q
Zr + O2 = ZrO2 + Q
Cr oxidation:
Cr + O2 = Cr2O3 + Q
Ni oxidation:
Ni + 0,5 O2 = NiO + Q
Heat generation Q is taken in the account in the total energy balance

22. 2222
HEFEST-ULR code verificationHEFEST-ULR code verification
Basis for verification Verified models
The analytical decision of a
problem of Stefana
Propagation of the melting
front
Salt experiments of RASPLAV
project
(NRC KI)
Convective heat exchange in
the conditions of crust
formation on a cooled wall
Experiments of series AW-200
of RASPLAV project
(NRC KI)
Dynamics of the molten pool
formation in a natural corium
Experiments of series SACR of
RASPLAV project
(NITI)
Corium interaction with
sacrificial materials

23. 2323
HEFEST-ULR code verification against analytical testsHEFEST-ULR code verification against analytical tests
Melt front propagation
Case of the low
heat conductivity of phases
Thin line – analytical solution
Thick line – calculation on the HEFEST-ULR
code
Case of the high
heat conductivity of phases
Thin line – analytical solution
Thick line – calculation on the HEFEST-ULR
code
0,00 0,04 0,08 0,12 0,16 0,20
1000
1100
1200
1300
1400
1500
1600
1700
1800
Расстояние, м
0.400E+01
0.160E+02
0.360E+02
0.640E+02
0.100E+03
0.144E+03
0.196E+03
0.256E+03
0.324E+03
0.400E+03
0,00 0,05 0,10 0,15 0,20 0,25 0,30 0,35 0,40 0,45 0,50 0,55 0,60
1000
1100
1200
1300
1400
1500
1600
1700
1800
Расстояние, м
0.100E+03
0.400E+03
0.900E+03
0.160E+04
0.250E+04
0.360E+04
0.490E+04
0.640E+04
0.810E+04
0.100E+05

24. 2424
HEFEST-ULR code verification against RASPLAV salt testsHEFEST-ULR code verification against RASPLAV salt tests
Temperatures of the internal and
external wall surfaces
Heat flux change
along the wall
0 10 20 30 40 50 60 70 80 90
400
410
420
430
440
450
460
470
T_exp_наруж
T_exp_внутр
T_calc_наруж
T_calc_внутр
Температура,
о
С
Угол от вертикали, град
0 10 20 30 40 50 60 70 80 90
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
2,0
2,2
2,4
Эксперимент
Расчёт
Нормированныйпотоктепла,q/qe
Угол от вертикали, град

25. 2525
HEFEST-ULR code verification against RASPLAV AW-200HEFEST-ULR code verification against RASPLAV AW-200 testtest
Temperature of the graphite
heater in experiment AW−200−1
Temperature of the wall and
corium in experiment AW−200−1
0 10000 20000 30000 40000 50000
0
400
800
1200
1600
2000
2400
2800
Температура,С
Время, с
Графитовый нагреватель
пирометр
0 10000 20000 30000 40000 50000 60000 70000
0
400
800
1200
1600
2000
2400
2800
Температура,С
Время, с
Кориум-расчёт
Кориум-пирометр
Сталь-расчёт
Сталь-термопара

26. 2626
HEFEST-ULR code verification against SACRHEFEST-ULR code verification against SACR-7-7 testtest
Model of chemical reactions
Corium С-32:
76 % UO2 + 9 % ZrO2 + 15 % Zr
Sacrificial Materials:
85 % Fe2O3 + 15 % Аl2О3
Initial composition

27. 2727
Composition after interaction
Calculation
61 % UO2 + 24 % ZrO2 + 2 % Zr +
0 % FeO + 3 % Al2O3 +10 % Fe
Experimental data
65 % UO2 + 20 % ZrO2 + 2 % Zr +
0 % FeO + 3 % Al2O3 +10 % Fe
HEFEST-ULR code verification against SACRHEFEST-ULR code verification against SACR-7-7 testtest
Model of chemical reactions

28. 2828
The Certificate of the State RegistrationThe Certificate of the State Registration
of the GEFEST-ULR Codeof the GEFEST-ULR Code

29. 2929
Analysis of overall performance of the core catcherAnalysis of overall performance of the core catcher
for VVER-1200for VVER-1200
Simulation of physical chemical processes in the core catcher
during severe accident on a VVER-1200 with help of HEFEST-
ULR code.
Severe accident scenario:
Large Break LOCA with simultaneous station blackout.
Main assumptions:
Double-ended rupture of a RCS D = 850 mm;
No operator actions.
Break location:
Cold leg of the RCS loop on the reactor inlet.

30. 3030
Input data: Mass of the sacrificial materials in the core catcherInput data: Mass of the sacrificial materials in the core catcher
Material Mass
Iron oxide,
ton
66
Aluminum
oxide, ton
28
Concrete,
ton
8
Steel, ton 64
Free
volume, m3
35

31. 3131
Calculation results:Calculation results: Corium behavior in the core catcherCorium behavior in the core catcher
9 minutes
From the onset of the first
corium portion (75 tons)
pouring into core catcher
47 minutes
The front of corium pool is
achieved of internal wall of
core catcher vessel
5 hours
Propagation of the front of
corium pool in radial
direction is stopped

32. In the initial phase In the long term
Calculation resultsCalculation results:: Corium temperature in the Core CatcherCorium temperature in the Core Catcher
0 0 .2 0 .4 0 .6 0 .8 1 1 .2 1 .4 1 .6 1 .8 2
В р е м я ( ч а с )
1 8 0 0
2 0 0 0
2 2 0 0
2 4 0 0
2 6 0 0
2 8 0 0
3 0 0 0
Температура(К)
С м е ш а н н ы й р а с п л а в
М е т а л л и ч е с к а я ф а з а
О к с и д н а я ф а з а
0 0 .5 1 1 .5 2 2 .5 3 3 .5 4 4 .5 5
В р е м я (с у т к и )
1 8 0 0
2 0 0 0
2 2 0 0
2 4 0 0
2 6 0 0
2 8 0 0
3 0 0 0
Температура(К)
С м е ш а н н ы й р а с п л а в
М е т а л л и ч е с к а я ф а з а
О к с и д н а я ф а з а
Mixed corium
Metal phase
Oxide phase
Mixed corium
Metal phase
Oxide phase
Time, hour Time, day
Temperature,K
Temperature,K
Temperature,K
Temperature,K

33. Evolution versus time Changing along a height
Calculation resultsCalculation results:: Maximum heat flux on external surfaceMaximum heat flux on external surface
of the core catcher vesselof the core catcher vessel
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0
В р е м я ( ч а с )
0
0 .2
0 .4
0 .6
0 .8
1
1 .2
q(МВт/м2)
К р и т и ч е с к и й т е п л о в о й п о т о к
0 0 .2 0 .4 0 .6 0 .8 1 1 .2
q ( М В т / м 2
)
0
0 .5
1
1 .5
2
2 .5
3
3 .5
4
4 .5
5
Высота(м)
К р и т и ч е с к и й
т е п л о в о й
п о т о к
Critical flux
Time, hour
Critical flux
Height,m

34. 3434
Calculation resultsCalculation results:: Hydrogen generationHydrogen generation
Ex-vessel stage of the accident: Melt localization in the core catcher
NPP project
In-vessel
phase
(kg)
Ex-vessel
phase
(kg)
Total
(kg)
Without core
catcher 470 1600 2070
With core
catcher 470 98 ~ 570
Hydrogen generation from
core catcher
Core catcher application for severe accident management removes a
sharpness of a hydrogen hazard during ex-vessel stage of the accident
Hydrogen generation during in-vessel
phase of the accident, first 24 hours
of the ex-vessel phase and total
hydrogen generation on NPP with
and without of the core catcher
0 1 2 3 4 5
0
1 5 0
0 1 2 3 4 5
В р е м я , с у т
Массакг,
3 0
6 0
9 0
1 2 0
Time, day
Mass,kg

35. 3535
SummarySummary
Application in modern projects of NPP with VVER the big capacity as one
of means core catcher, specially provided for severe accident
management, provides safety increase.
Safety increase is reached by means of exception of release of liquid and
firm radioactive materials from core catcher, reduction of quantity of
generated hydrogen.
The key role in working out core catcher is played by a choice and
optimization of composition of sacrificial material placed in core catcher
vessel.
On an example of the settlement analysis of behavior of a corium in core
catcher for VVER-1200 it is shown that core catcher effectively carries out
the functions on localization and long-term cooling of a corium.

36. 3636