| 1. |
- 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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| 2. |
- 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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| 3. |
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| 4. |
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| 5. |
- 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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| 6. |
- Bechta, Sevostian, et al.
(författare)
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Interaction between molten corium UO2+X-ZrO2-FeO y and VVER vessel steel
- 2009
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Ingår i: Proceeding of International Conference on Advances in Nuclear Power Plants, ICAPP 2008. - : Curran Associates, Inc.. - 9781605607870 ; , s. 210-218
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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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| 7. |
- Bechta, Sevostian, et al.
(författare)
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INTERACTION BETWEEN MOLTEN CORIUM UO2+x-ZrO2-FeOy AND VVER VESSEL STEEL
- 2010
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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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| 8. |
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| 9. |
- Bechta, Sevostian, et al.
(författare)
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VVER vessel steel corrosion at interaction with molten corium in oxidizing atmosphere
- 2009
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Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 239:6, s. 1103-1112
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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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| 10. |
- Bechta, Sevostian, et al.
(författare)
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Water boiling on the corium melt surface under VVER severe accident conditions
- 2000
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Ingår i: Nuclear Engineering and Design. - 0029-5493 .- 1872-759X. ; 195:1, s. 45-56
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results are presented on the interaction of corium melt with water supplied on its surface. The tests were conducted in the `Rasplav-2' experimental facility. Corium melt was generated by induction melting in the cold crucible. The following data were obtained: heat transfer at boiling water-melt surface interaction, gas and aerosol release, post-interaction solidified corium structure. The corium melt charge had the following composition, mass%: 60% UO2+x-16% ZRO2-15% Fe2O3-6% Cr2O3-3% Ni2O3. The melt surface temperature ranged within 1920-1970 K.
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