| 1. |
- Asmolov, V.G., et al.
(författare)
-
Crucible-type core catcher for VVER-1000 reactor
- 2005
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Ingår i: Proceedings of the American Nuclear Society - International Congress on Advances in Nuclear Power Plants 2005, ICAPP'05. - : Curran Associates, Inc.. - 9781604236934 ; , s. 1221-1227
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Konferensbidrag (refereegranskat)abstract
- For new designs of NPPs with VVER-1000 reactors a crucible-type core catcher has been developed to stabilize and cool down molten corium in the reactor pit. The paper addresses distinguishing features of the concept including the "sacrificial" material and the core catcher design. Main phenomena in the catcher have been analyzed.
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| 2. |
- Bechta, Sevostian, et al.
(författare)
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Experimental studies of oxidic molten corium-vessel steel interaction
- 2001
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Ingår i: Nuclear Engineering and Design. - 0029-5493 .- 1872-759X. ; 210:1-3, s. 193-224
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Tidskriftsartikel (refereegranskat)abstract
- The experimental results of molten corium-steel specimen interaction with molten corium on the 'Rasplav-2' test facility are presented. In the experiments, cooled vessel steel specimens positioned on the molten pool bottom and uncooled ones lowered into the molten pool were tested. Interaction processes were studied for different corium compositions, melt superheating and in alternative (inert and air) overlying atmosphere. Hypotheses were put forward explaining the observed phenomena and interaction mechanisms. The studies presented in the paper were aimed at the detection of different corium-steel interaction mechanisms. Therefore certain identified phenomena are more typical of the ex-vessel localization conditions than of the in-vessel corium retention. Primarily, this can be referred to the phenomena of low-temperature molten corium-vessel steel interaction in oxidizing atmosphere.
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| 3. |
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| 4. |
- Bechta, Sevostian, et al.
(författare)
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Influence of corium oxidation on fission product release from molten pool
- 2010
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Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 240:5, s. 1229-1241
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Tidskriftsartikel (refereegranskat)abstract
- Qualitative and quantitative determination of the release of low-volatile fission products and core materialsfrom molten oxidic corium was investigated in the EVAN project under the auspices of ISTC. Theexperiments carried out in a cold crucible with induction heating and RASPLAV test facility are described.The results are discussed in terms of reactor application; in particular, pool configuration, melt oxidationkinetics, critical influence of melt surface temperature and oxidation index on the fission productrelease rate, aerosol particle composition and size distribution. The relevance of measured high releaseof Sr from the molten pool for the reactor application is highlighted. Comparisons of the experimentaldata with those from the COLIMA CA-U3 test and the VERCORS tests, as well as with predictions fromIVTANTHERMO and GEMINI/NUCLEA codes are made. Recommendations for further investigations areproposed following the major observations and discussions.
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| 5. |
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| 6. |
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| 7. |
- Komlev, Andrei A., et al.
(författare)
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Effect of the sequence of chemical transformations on the spatial segregation of components and formation of periclase-spinel nanopowders in the MgO–Fe2O3–H2O System
- 2016
-
Ingår i: Russian journal of applied chemistry. - : Maik Nauka-Interperiodica Publishing. - 1070-4272 .- 1608-3296. ; 89:12, s. 1932-1938
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Tidskriftsartikel (refereegranskat)abstract
- Specific features of the process in which oxide nanopowders are formed in a hydrothermal treatment of coprecipitated magnesium and iron oxides were studied. It was shown that the rate at which oxide nanoparticles are formed increases when reagents structurally close to the final product are used. It was found that, with the hydrothermal treatment of coprecipitated magnesium and iron hydroxides at 450°C combined with the subsequent thermal treatment in air at temperatures of 400–600°C, it is possible to obtain a homogeneous mixture of nanocrystalline powders based on an iron-containing spinel phase and magnesium oxide.
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| 8. |
- Murari, A., et al.
(författare)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
-
Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 9. |
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| 10. |
- Sulatsky, A.A., et al.
(författare)
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Molten corium interaction with oxidic sacrificial material of WER core catcher
- 2005
-
Ingår i: Proceedings of the American Nuclear Society. - 9781604236934 ; , s. 1238-1246
-
Konferensbidrag (refereegranskat)abstract
- The results of experimental studies on the interaction between the oxidic corium melt containing unoxidized zirconium and sacrificial materials of the VVER core catcher are presented. The phenomena of suboxidized corium interaction with sacrificial material have been determined and appropriate model has been developed.
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| 11. |
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| 12. |
- Almjashev, V.I., et al.
(författare)
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Eutectic crystallization in the FeO(1.5)-UO(2+x)-ZrO(2) system
- 2009
-
Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 389:1, s. 52-56
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Tidskriftsartikel (refereegranskat)abstract
- Results of the investigation of the FeO(1.5)-UO(2+x)-ZrO(2) system in air are presented. The eutectic position and the content of the phases crystallized at this point have been determined. The temperature and the composition of the ternary eutectic are 1323 +/- 7 degrees C and 67.4 +/- 1.0 FeO(1.5), 30.5 +/- 1.0 UO(2+x), 2.1 +/- 0.2 ZrO(2) mol.%, respectively. The solubilities of FeO(1.5) and ZrO(2) in the UO(2+x)(FeO(1.5), ZrO(2)) solid solution correspond to respectively 3.2 and 1.1 mol.%. The solubilities of UO(2) and ZrO(2) in FeO(1.5) are not significant. The existence of a solid solution on the basis of U(Zr)FeO(4) compound is found. The ZrO(2) Solubility in this solid solution is 7.0 mol.%.
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| 13. |
- Almjashev, V.I., et al.
(författare)
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Phase equilibria in the FeO(1+x)-UO(2)-ZrO(2) system in the FeO(1+x)-enriched domain
- 2010
-
Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 400:2, s. 119-126
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results of the investigation of the FeO(1+x)UO(2)-ZrO(2) system in neutral atmosphere are presented. The ternary eutectic position and the composition of the phases crystallized at this point have been determined. The phase diagram is constructed for the FeO(1+x)-enriched region and the onset melting temperature of 1310 degrees C probably represents a local minimum and so will be a determining factor in this system and its application to safety studies in nuclear reactors.
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| 14. |
- Almjashev, V.I., et al.
(författare)
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Ternary eutectics in the systems FeO-UO2-ZrO2 and Fe2O3-U3O8-ZrO21
- 2011
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Ingår i: Radiochemistry. - 1066-3622. ; 53:1, s. 13-18
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Tidskriftsartikel (refereegranskat)abstract
- The systems FeO–UO2–ZrO2 (in inert atmosphere) and Fe2O3–U3O8–ZrO2 (in air) were studied. Forthe FeO–UO2–ZrO2 system, the eutectic temperature was found to be 1310°С, with the following componentconcentrations (mol %): 91.8 FeO, 3.8 UO2, and 4.4 ZrO2. For the Fe2O3–U3O8–ZrO2 system, the eutectictemperature was found to be 1323°С, with the following component concentrations (mol %): 67.4 FeO1.5,30.5 UO2.67, and 2.1 ZrO2. The solubility limits of iron oxides in the phases based on UO2(ZrO2,FeO) andUO2.67(ZrO2,FeO1.5) were determined
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| 15. |
- Almyashev, V. I., et al.
(författare)
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Oxidation effects during corium melt in-vessel retention
- 2016
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Ingår i: Nuclear Engineering and Design. - : Elsevier. - 0029-5493 .- 1872-759X. ; 305, s. 389-399
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Tidskriftsartikel (refereegranskat)abstract
- In the in-vessel corium retention studies conducted on the Rasplav-3 test facility within the ISTC METCOR-P project and OECD MASCA program, experiments were made to investigate transient processes taking place during the oxidation of prototypic molten corium. Qualitative and quantitative data have been produced on the sensitivity of melt oxidation rate to the type of oxidant, melt composition, molten pool surface characteristics. The oxidation rate is a governing factor for additional heat generation and hydrogen release; also for the time of secondary inversion of oxidic and metallic layers of corium molten pool.
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| 16. |
- Asmolov, V.G., et al.
(författare)
-
Partitioning of Zr, U and FP between Molten Oxidic and Metallic Corium
- 2004
-
Ingår i: Proceeding of MASCA Seminar.
-
Konferensbidrag (refereegranskat)abstract
- Interaction of molten corium and liquid iron/stainless steel has been studied in different tests of theMASCA-1 program. These tests utilized the technology of induction melting in a cold crucible. Themasses of tested corium were approximately 0.5, 2 and 100 kg. Representative quantities of Mo, Ru,SrO, BaO, CeO2 and La2O3 served as fission product simulants.After the suboxidized melt - steel interaction U and Zr have been found in the metallic phase.To quantify the partitioning of Zr, U and fission products an extensive experimental program has beenperformed. The following key parameters have been identified: oxygen potential in the melt (degree ofZr-oxidation), the corium/steel mass ratio and U/Zr ratio. The paper discusses the influence of theseparameters on the partitioning of the main species.
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| 17. |
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| 18. |
- Bechta, Sevostian, et al.
(författare)
-
Corium phase equilibria based on MASCA, METCOR and CORPHAD results
- 2008
-
Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 238:10, s. 2761-2771
-
Tidskriftsartikel (refereegranskat)abstract
- Experimental data on component partitioning between suboxidized corium melt and steel in the invessel melt retention (IVR) conditions are compared. The data are produced within the OECD MASCAprogram and the ISTC CORPHAD project under close-to-isothermal conditions and in the ISTC METCORproject under thermal gradient conditions. Chemical equilibrium in the U–Zr–Fe(Cr,Ni,. . .)–O system isreached in all experiments. In MASCA tests the molten pool formed under inert atmosphere has twoimmiscible liquids, oxygen-enriched (oxidic) and oxygen-depleted (metallic), resulting of the miscibilitygap of the mentioned system. Sub-system data of the U–Zr–Fe(Cr,Ni,. . .)–O phase diagram investigatedwithin the ISTC CORPHAD project are interpreted in relation with the MASCA results. In METCOR teststhe equilibrium is established between oxidic liquid and mushy metallic part of the system. Results ofcomparison are discussed and the implications for IVR noted.
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| 19. |
- Bechta, Sevostian, et al.
(författare)
-
CORPHAD and METCOR ISTC projects
- 2005
-
Ingår i: Proceedings of The first European Review Meeting on Severe Accident Research (ERMSAR-2005).
-
Konferensbidrag (refereegranskat)abstract
- The ongoing CORPHAD Project (Phase Diagrams for Multicomponent SystemsContaining Corium and Products of its Interaction with NPP Materials) started in August2001. The main aim of the project is to experimentally determine the relevantphysicochemical data on phase diagrams of binary, ternary, quaternary and prototypic multicomponent systems, which are important for analysis and modelling of a severe accident (SA)and efficient planning of severe accident management (SAM) measures. The data should bedirectly used for the European NUCLEA database development and validation. The followingsystems are in the focus of the project: (1) UO2 – FeO, (2) ZrO2 – FeO, (3) SiO2– Fe2O3, (4)UO2 – SiO2, (5) UO2 – ZrO2-FeO, (6) UO2 – ZrO2-FeOy, (7) U-O-Fe, (8) Zr-O-Fe, (9) U-OZr, (10) U-Zr-Fe-O, (11) complex corium mixtures.The experimentally determined data of the listed diagrams include: coordinates ofcharacteristic points (eutectics, peritectics and others); liquidus and solidus concentrationcurves; component solubility limits in the solid phase; tie line coordinates and temperatureconcentration regions of the miscibility gap. Different methodologies are used for the phasediagram study. Classical methods of thermal analysis, like DTA and DSC are combined withmethods specifically developed for corium studies.The METCOR project (Investigation of Corium Melt Interaction with NPP ReactorVessel Steel) started in April 1999. The objectives of the project are to qualify and to quantifyphysico-chemical phenomena of corium melt interaction with reactor vessel steel cooled fromthe outside. The variable parameters of the interaction tests are: oxygen potential in thesystem, corium composition, interaction interface temperature and heat flux from corium tosteel. The medium scale tests with corium mass of about 2 kg are carried out by using highfrequency induction heating of the corium melt in a cold crucible.The METCOR & CORPHAD work-packages are performed by Russian partners inclose collaboration with leading European scientific institutes in the area of corium researchas well as with the European nuclear industry.This paper briefly describes the results obtained in both projects and their possibleapplication for SA analysis and SAM. The paper concludes with recommendations for futureresearch activities in the framework of METCOR and CORPHAD projects.
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| 20. |
- Bechta, Sevostian, et al.
(författare)
-
Corrosion of vessel steel during its interaction with molten corium : Part 2. Model development
- 2006
-
Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 236:13, s. 1362-1370
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Tidskriftsartikel (refereegranskat)abstract
- An experimental examination of the cooled vessel steel corrosion during the interaction with molten corium is presented. The experiments havebeen conducted on “Rasplav-2” test facility and followed up with physico-chemical and metallographic analyses of melt samples and coriumspecimeningots. The results discussed in the first part of the paper have revealed specific corrosion mechanisms for air and inert atmosphere abovethe melt. Models have been proposed based on this information and approximate curves constructed for the estimation of the corrosion rate orcorrosion depth of vessel steel in conditions simulated by the experiments.
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| 21. |
- Bechta, Sevostian, et al.
(författare)
-
Corrosion of vessel steel during its interaction with molten corium : Part 1. Experimental
- 2006
-
Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 236:17, s. 1810-1829
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Tidskriftsartikel (refereegranskat)abstract
- This paper is concerned with corrosion of a cooled vessel steel structure interacting with molten corium in air and neutral (nitrogen) atmospheresduring an in-vessel retention scenario. The data on corrosion kinetics at different temperatures on the heated steel surface, heat flux densities andoxygen potential in the system are presented. The post-test physico-chemical and metallographic analyses of melt samples and the corium–specimeningot have clarified certain mechanisms of steel corrosion taking place during the in-vessel melt interaction.
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| 22. |
- Bechta, Sevostian, et al.
(författare)
-
Experimental study of interactions between suboxidized corium and reactor vessel steel
- 2006
-
Ingår i: Proceedings of the 2006 International Congress on Advances in Nuclear Power Plants, ICAPP'06. - 0894486985 - 9780894486982 ; , s. 1355-1362
-
Konferensbidrag (refereegranskat)abstract
- One of the critical factors in the analysis of in-vessel melt retention is the vessel strength. It is, in particular, sensitive to the thickness of intact vessel wall, which, in its turn, depends on the thermal conditions and physicochemical interactions with corium. Physicochemical interaction of prototypic UO2-ZrO2-Zr corium melt and VVER vessel steel was examined during the 2nd Phase of the ISTC METCOR Project. Rasplav-3 test facility was used for conducting four tests, in which the Zr oxidation degree and interaction front temperature were varied; in one of the tests, stainless steel was added to the melt. Direct experimental measurements and posttest analyses were used for determining corrosion kinetics and maximum corrosion depth (i.e. the physicochemical impact of corium on the cooled vessel steel specimens), as well as the steel temperature conditions during the interaction, and finally the structure and composition of crystallized ingots, including the interaction zone. The minimum temperature on the interaction front boundary, which determined its final position and maximum corrosion depth was ∼ 1090°C. An empirical correlation for calculation of corrosion kinetics has been derived.
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| 23. |
- Bechta, Sevostian, et al.
(författare)
-
Interaction between molten corium UO2+X-ZrO2-FeO y and VVER vessel steel
- 2009
-
Ingår i: Proceeding of International Conference on Advances in Nuclear Power Plants, ICAPP 2008. - : Curran Associates, Inc.. - 9781605607870 ; , s. 210-218
-
Konferensbidrag (refereegranskat)abstract
- In case of an in-vessel corium retention (1VR) the deterioration of vessel steel properties can be caused both by the steel melting and by its physicochemical interaction with corium. The interaction behavior has been studied in the medium-scale experiments with a prototypic corium within the METCOR project. The resulting experimental data give an insight into the steel corrosion during its interaction with U02+x- Zr02- FeOy melt in air and steam. It has been observed that the corrosion rate is almost the same in air and steam atmosphere; if the temperature on the interaction interface increases beyond a certain level, corrosion intensifies, which is explained by the formation of liquid phases in the interaction zone. The available experimental data have been used for developing a correlation of corrosion rate versus temperature and heat flux.
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| 24. |
- Bechta, Sevostian, et al.
(författare)
-
INTERACTION BETWEEN MOLTEN CORIUM UO2+x-ZrO2-FeOy AND VVER VESSEL STEEL
- 2010
-
Ingår i: Nuclear Technology. - : American Nuclear Society. - 0029-5450 .- 1943-7471. ; 170:1, s. 210-218
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Tidskriftsartikel (refereegranskat)abstract
- In case of in-vessel corium retention during a severe accident in a light water reactor, weakening of the vessel wall and deterioration of the vessel steel properties can be caused both by the melting of the steel and by its physicochemical interaction with corium. The interaction behavior has been studied in medium-scale experiments with prototypic corium. The experiments yielded data for the steel corrosion rate during interaction with UO2+x-ZrO2-FeOy melt in air and steam at different steel surface temperatures and heat fluxes from the corium to the steel. It has been observed that the corrosion rates in air and steam atmosphere are almost the same. Further, if the temperature at the interface increases beyond a certain level, corrosion intensifies. This is explained by the formation of liquid phases in the interaction zone. The available experimental data have been used to develop a correlation for the corrosion rate as afunction of temperature and heat flux.
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| 25. |
- Bechta, Sevostian, et al.
(författare)
-
New experimental results on the interaction of molten corium with reactor vessel steel
- 2004
-
Ingår i: Proceedings of the 2004 International Congress on Advances in Nuclear Power Plants, ICAPP'04. - : American Nuclear Society. - 0894486802 ; , s. 1072-1081
-
Konferensbidrag (refereegranskat)abstract
- In order to justify the concept of in-vessel core melt retention, it is necessary to understand the thermal and physico-chemical phenomena. Especially the interaction of the molten pool with the reactor vessel during outside cooling needs to be understood. These phenomena are very complex, in particular, where interactions with the oxidic melt are concerned. In the early stages of the retention process, the oxidic corium and the vessel steel interact under the conditions of low oxygen potential in the melt. These conditions can be simulated by a molten corium having the composition UO2/ZrO 2Zr, where the degree of Zr-oxidation is in the range between 30 % (C-30) and 100 % (C-100). Corresponding experiments with prototypic melts at low oxygen potentials are being performed in the ISTC METCOR project 2nd phase. These are: MC 5 of corium composition 71w%UO2-29w%ZrO 2 (C-100) in neutral atmosphere (argon), MC 6 of corium composition 76w%UO2-9w%ZrO2-15w%Zr (C∼30), also in argon. In test MC 5, the interaction of molten C-100 corium with a water-cooled steel specimen was studied for the following maximum temperatures at the specimen surface: 1075°C, 1180°C, 1315°C and 1435°C. The total duration of the experiment was ∼ 36 hours. The MC5 test serves as a reference test for determining the characteristics of the interaction between oxidic melt and steel specimen under the conditions of minimum chemical interaction potential. To investigate the effect of substoichiometry, test MC 6 was then performed with suboxidized molten corium C∼30. The maximum surface temperature of the cooled steel specimen was held at ∼ 1400°C. The test duration was ∼ 10 hours. The ablation phenomena were found to differ significantly from those observed both in the reference test, as well as in former tests with oxidized melts, as they involved the formation of a low-melting metallic phase at the interface which contains iron, zirconium and uranium. The paper summarizes the results of the experiments and of the performed posttest analysis for tests MC 5 and MC 6.
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| 26. |
- Bechta, Sevostian, et al.
(författare)
-
Phase diagram of the UO2-FeO1+x system
- 2007
-
Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 362:1, s. 46-52
-
Tidskriftsartikel (refereegranskat)abstract
- Phase-relation studies of the UO2–FeO1+x system in an inert atmosphere are presented. The eutectic point has beendetermined, which corresponds to a temperature of (1335 ± 5) C and a UO2 concentration of (4.0 ± 0.1) mol.%. Themaximum solubility of FeO in UO2 at the eutectic temperature has been estimated as (17.0 ± 1.0) mol.%. Liquidus temperaturesfor a wide concentration range have been determined and a phase diagram of the system has been constructed.
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| 27. |
- Bechta, Sevostian, et al.
(författare)
-
Phase diagram of the ZrO2-FeO system
- 2006
-
Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 348:1-2, s. 114-121
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Tidskriftsartikel (refereegranskat)abstract
- The results on the ZrO2–FeO system studies in a neutral atmosphere are presented. The refined eutectic point has beenfound to correspond to a ZrO2 concentration of 10.3 ± 0.6 mol% at 1332 ± 5 C. The ultimate solubility of iron oxide inzirconia has been determined in a broad temperature range, taking into account the ZrO2 polymorphism. A phase diagramof the pseudobinary system in question has been constructed.
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| 28. |
- Bechta, Sevostian, et al.
(författare)
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Phase Relations in the ZrO2–FeO System
- 2006
-
Ingår i: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 51:2, s. 325-331
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of the investigation of the ZrO2-FeO system under an inert atmosphere. We have refined the position of the eutectic point, which lies at 1332 +/- 5 degrees C and 10.3 +/- 0.6 mol % ZrO2. The iron oxide solubility boundaries in zirconium dioxide have been determined over a wide temperature range taking into account the polymorphism in ZrO2. A phase diagram for the system has been designed.
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| 29. |
- Bechta, Sevostian, et al.
(författare)
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Phase transformation in the binary section of the UO2-FeO-Fe system
- 2007
-
Ingår i: Radiochemistry (New York, N.Y.). - 1066-3622 .- 1608-3288. ; 49:1, s. 20-24
-
Tidskriftsartikel (refereegranskat)abstract
- Phase transformations in the oxide binary section of the UO2-FeO-Fe ternary system were studied. The melting onset point of the UO2-FeO heterogeneous system (1335±5°C) was determined and the fusion curve of this system was constructed. The limiting solubility of FeO in the UO2 solid solution was measured. The changes in crystal parameters in formation of the solid solution were determined. Uranium dioxide was found to be insoluble in the wüstite phase (FeO).
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| 30. |
- Bechta, Sevostian, et al.
(författare)
-
VVER vessel steel corrosion at interaction with molten corium in oxidizing atmosphere
- 2009
-
Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 239:6, s. 1103-1112
-
Tidskriftsartikel (refereegranskat)abstract
- The long-term in-vessel corium retention (IVR) in the lower head bears a risk of the vessel wall deterioration caused by steel corrosion. The ISTC METCOR Project has studied physicochemical impact of prototypic coria having different compositions in air and steam and has generated valuable experimental data on vessel steel corrosion. It is found that the corrosion rate is sensitive to corium composition, but the composition of oxidizing above-melt atmosphere (air, steam) has practically no influence on it. A model of the corrosion process that integrates the experimental data, is proposed and used for development of correlations.
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| 31. |
- Granovsky, V. S., et al.
(författare)
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Modeling of melt retention in EU-APR1400 ex-vessel core catcher
- 2012
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Ingår i: International Congress on Advances in Nuclear Power Plants 2012, ICAPP 2012. - 9781622762101 ; , s. 1412-1421
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Konferensbidrag (refereegranskat)abstract
- A core catcher is adopted in the EU-APR1400 reactor design for management and mitigation of severe accidents with reactor core melting. The core catcher concept incorporates a number of engineering solutions used in the catcher designs of European EPR and Russian WER-1000 reactors, such as thin-layer corium spreading for better cooling, retention of the melt in a water-cooled steel vessel, and use of sacrificial material (SM) to control the melt properties. SM is one of the key elements of the catcher design and its performance is critical for melt retention efficiency. This SM consists of oxide components, but the core catcher also includes sacrificial steel which reacts with the metal melt of the molten corium to reduce its temperature. The paper describes the required properties of SM. The melt retention capability of the core catcher can be confirmed by modeling the heat fluxes to the catcher vessel to show that it will not fail. The fulfillment of this requirement is demonstrated on the example of LBLOCA severe accident. Thermal and physicochemical interactions between the oxide and metal melts, interactions of the melts with SM, sacrificial steel and vessel, core catcher external cooling by water and release of non-condensable gases are modeled.
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| 32. |
- Granovsky, V. S., et al.
(författare)
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Oxidation effect on steel corrosion and thermal loads during corium melt in-vessel retention
- 2014
-
Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 278, s. 310-316
-
Tidskriftsartikel (refereegranskat)abstract
- During a severe accident with core meltdown, the in-vessel molten core retention is challenged by the vessel steel ablation due to thermal and physicochemical interaction of melt with steel. In accidents with oxidizing atmosphere above the melt surface, a low melting point UO2+x-ZrO2-FeOy corium pool can form. In this case ablation of the RPV steel interacting with the molten corium is a corrosion process. Experiments carried out within the International Scientific and Technology Center's (ISTC) METCOR Project have shown that the corrosion rate can vary and depends on both surface temperature of the RPV steel and oxygen potential of the melt. If the oxygen potential is low, the corrosion rate is controlled by the solid phase diffusion of Fe ions in the corrosion layer. At high oxygen potential and steel surface layer temperature of 1050 degrees C and higher, the corrosion rate intensifies because of corrosion layer liquefaction and liquid phase diffusion of Fe ions. The paper analyzes conditions under which corrosion intensification occurs and can impact on in-vessel melt retention (IVR).
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| 33. |
- Gusarov, V.V., et al.
(författare)
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Distribution of components between immiscible melts of a system under nonisothermal conditions
- 2006
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Ingår i: Glass Physics and Chemistry. - 1087-6596 .- 1608-313X. ; 32:6, s. 638-642
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the temperature difference at the interface on the redistribution of components between coexisting liquid phase is analyzed using the U-Zr-O system as an example. It is demonstrated that, in this system, there can arise new dynamic effects in boundary regions of the coexisting phases. These effects are of considerable practical importance, for example, for the prediction of the behavior of the system in severe accidents at nuclear power plants.
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| 34. |
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| 35. |
- Gusarov, V.V., et al.
(författare)
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Interaction of a material based on aluminum and iron oxides with a metal melt
- 2007
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Ingår i: Russian journal of applied chemistry. - 1070-4272 .- 1608-3296. ; 80:4, s. 528-535
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Tidskriftsartikel (refereegranskat)abstract
- Interaction of an oxide material with a melt of metals in the combustion mode was studied experimentally. The conditions in which processes of this kind can occur without any increase in the temperatureof the environment are possible were analyzed.
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| 36. |
- Gusarov, V.V., et al.
(författare)
-
Method for producing ceramic materials incorporating ferric oxide, alumina, and silicon dioxide for nuclear-reactor molten core trap
- 2002
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Patent (populärvet., debatt m.m.)abstract
- NOVELTY - Production of ceramic materials for nuclear reactor molten core trap involves preparation of charge by milling and mixing components, and producing molding powder from charge. This molding powder is molded and formed into briquettes, which are calcined in an air environment at 1300 - 1380 degreesC for 2-14 hr. The briquettes are crushed, the powder is milled and sized to fractions, and mixed with binder. The parts are molded and calcined at 1200-1300 degreesC for 4-14 hr. Silicon dioxide and part of the alumina are introduced into the charge as kaolin, whose content is higher than the desired content of silicon dioxide in material by 2.1-2.3 times. USE - In nuclear power engineering, for confining molten core in water-cooled tank reactors. ADVANTAGE - Enhanced reproducibility of physical and mechanical properties of molten core sacrificial ceramic materials.
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| 37. |
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| 38. |
- Gusarov, V.V., et al.
(författare)
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Oxidic material for nuclear reactor core melt catcher
- 2001
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Patent (populärvet., debatt m.m.)abstract
- NOVELTY - Oxide material of molten core catcher incorporating Al2O3,SiO2, also contains Fe2O3 and/or Fe3O4, and target dopant of one or more oxides of following group: SrO,CeO2,BaO,Y2O3,La2O3. Proportion of ingredients is, in mass percent: Fe2O3 and/or Fe3O4, 46-80; Al2O3, 16-50; SiO2, 1-4; target dopant, 3-15. The material has content of radioactive strontium and cerium isotopes in gas phase above molten core that is reduced by 2-7 times. USE - For nuclear reactor molten core catcher. ADVANTAGE - Reduced radioactivity of molten core.
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| 39. |
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| 40. |
- Gusarov, V.V., et al.
(författare)
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Oxidmaterial for fallan av en karnreaktors smalt mantel
- 2001
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Patent (populärvet., debatt m.m.)abstract
- The inventive oxide material for a molten-core catcher of a nuclear reactor comprises Fe>23< and /or Fe>34< and Al>23<. The content of Al>23< and /or Fe>34 23 <%. Said material can also contain up to 4 mass % of SiO2, preferably from 1 to 4 mass %. The material can be embodied in the form of a ceramic material or concrete which additionally contains up to 20 mass % of cement binder.; The inventive oxide material for a molten-core catcher of a nuclear reactor comprises Fe2O3 and /or Fe3O4 and Al2O3. The content of Al2O3 and /or Fe3O4 ranges from 46 to 80 mass %, and Al2O3 from 16 to 50 mass %. Said material can also contain up to 4 mass % of SiO2, preferably from 1 to 4 mass %. The material can be embodied in the form of a ceramic material or concrete which additionally contains up to 20 mass % of cement binder.
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| 41. |
- Gusarov, V.V., et al.
(författare)
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Physicochemical Modeling and Analysis of the Interaction between a Core Melt of the Nuclear Reactor and a Sacrificial Material
- 2005
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Ingår i: Glass Physics and Chemistry. - : Springer Science and Business Media LLC. - 1087-6596 .- 1608-313X. ; 31:1, s. 53-66
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Tidskriftsartikel (refereegranskat)abstract
- -The problems regarding the design of a new class of materials, namely, sacrificial materials for usein devices intended for localization of a core melt of the nuclear reactor, are considered. Criteria are proposedfor the proper choice of the chemical composition of a sacrificial material, as well as of the composition andmicrostructure of its constituents. The possible alternatives are outlined and analyzed. The results of designinga variant of the composition of sacrificial materials are presented. The experimental data on the interaction ofan oxide sacrificial material with simulators of the metal and oxide phases of the core melt are discussed. A newtype of combustion of materials, namely, the liquid-phase combustion, is revealed. It is demonstrated that thematerial designed can be used in systems intended for localization of a core melt of the nuclear reactor.
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| 42. |
- Gusarov, V.V., et al.
(författare)
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Physicochemical simulation of the combustion of materials with the total endothermal effect
- 2007
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Ingår i: Glass Physics and Chemistry. - 1087-6596 .- 1608-313X. ; 33:5, s. 492-497
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Tidskriftsartikel (refereegranskat)abstract
- A new type of combustion, namely, the combustion of materials without heating of the environment, is described, and the conditions under which this process can occur are analyzed. It is demonstrated that the possibility of occurring the process under consideration depends substantially on the microstructure of the material. The characteristics of the material for which the liquid-phase combustion takes place without an increase in the temperature of the melt are determined using the interaction of a material based on iron and aluminum oxides with the Fe-Zr-O melt as an example.
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| 43. |
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| 44. |
- Khabensky, V. B., et al.
(författare)
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Effect of temperature gradient on chemical element partitioning in corium pool during in-vessel retention
- 2018
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Ingår i: Nuclear Engineering and Design. - : Elsevier Ltd. - 0029-5493 .- 1872-759X. ; 327, s. 82-91
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents some results of the ISTC (International Science and Technology Center)-financed project ‘Investigation of Corium Melt Interaction with NPP Reactor Vessel Steel’ (METCOR). In the METCOR experiments the metallic phase of a two-liquid system was produced by the interaction between hot suboxidized corium and cooled VVER vessel steel, with the steel being corroded. Models of corrosion mechanisms in the considered conditions are used to systematize data on the limiting temperature of corrosion/(dissolution) of the vessel steel. A considerable influence of thermal gradient conditions is shown, which has to be taken into account in the analysis of molten pool behaviour.
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| 45. |
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| 46. |
- Khabensky, V.B., et al.
(författare)
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Severe accident management concept of the VVER-1000 and the justification of corium retention in a crucible-type core catcher
- 2009
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Ingår i: Nuclear Engineering and Technology. - 1738-5733. ; 41:5, s. 561-574
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Tidskriftsartikel (refereegranskat)abstract
- First ex-vessel core catcher has been applied to the practical design of NPPs with VVER-1000 reactors built in China(Tyanvan) and India (Kudankulam) for severe accident management (SAM) and mitigation of SA consequences. The paperpresents the concept and basic design of this crucible-type core catcher as well as an evaluation of its efficiency. Theimportant role of oxidic sacrificial material is discussed. Insight into the behaviour of the molten pool, which forms in thecatcher after core relocation from the reactor vessel, is provided. It is shown that heat loads on the water-cooled vessel wallsare kept within acceptable limits and that the necessary margins for departure from nucleate boiling (DNB) and of vesselfailure caused by thermo-mechanical stress are satisfactorily provided for.
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| 47. |
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| 48. |
- Mezentseva, L.P., et al.
(författare)
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Phase and chemical transformations in the SiO2-Fe2O3(Fe3O4) system at various oxygen partial pressures
- 2006
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Ingår i: Russian Journal of Inorganic Chemistry. - 0036-0236 .- 1531-8613. ; 51:1, s. 118-125
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Tidskriftsartikel (refereegranskat)abstract
- The SiO2-Fe2O3(F3O4) system has been studied in air, oxygen, and an inert atmosphere. The dissociation temperatures for iron oxides, the onset and full melting temperatures for coexisting phases, and the melt demixing temperatures have been determined as a function of the oxygen partial pressure. A scenario of the phase and chemical transformations in the title systems has been developed.
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