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Journal Articles

Study on the discharge behavior of the molten-core materials through the control rod guide tube; Investigations of the effect of an internal structure in the control rod guide tube on the discharge behavior

Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji; Akaev, A.*; Vurim, A.*; Baklanov, V.*

Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-13) (Internet), 12 Pages, 2022/09

The In-Vessel Retention (IVR) of molten-core in Core Disruptive Accidents (CDAs) is of prime importance in enhancing the safety of sodium-cooled fast reactors. One of the main subjects in ensuring IVR is to design the Control Rod Guide Tube (CRGT) which allows effective discharge of molten core materials from the core region. The effectiveness of the CRGT design is assessed through CDA analyses, and it is reasonable for these analyses to develop a computer code collaborated with experimental researches. Thus, experiments addressing the discharge behavior of the molten-core materials through the CRGT have proceeded as one of the subjects in the collaboration research named the EAGLE-3 project, and the obtained experimental results are reflected in the development of the SIMMER code. In this project, a series of out-of-pile tests using molten-alumina as the fuel simulant was conducted to understand the discharge behavior of molten-core materials through the CRGT. In this study, in order to investigate the effect of an internal structure in the CRGT on the discharge behavior of the molten-core materials, the data of an out-of-pile test in which the molten-alumina penetrated to a duct with the internal structure were analyzed. In addition, the post-test analysis using the SIMMER code was conducted and the results were compared with the test results.

Journal Articles

Study on the discharge behavior of molten-core through the control rod guide tube in the core disruptive accident of SFR

Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji; Ganovichev, D. A.*; Baklanov, V. V.*

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 9 Pages, 2019/05

In order to ensure In-Vessel Retention (IVR) of molten-core in Core Disruptive Accident (CDA), we are investigating the possibility of the molten-core discharge through the control rod guide tube (CRGT) to prevent energetics due to exceeding the prompt criticality. Internal structures of the CRGT, such as a sodium-flow regulator when the CRGT is connected to the high-pressure plenum, may disturb the discharge of molten-core from the core region. Based on above background, an experimental program to clarify characteristics of molten-core discharge through the CRGT has been commenced as one of subjects under a joint study with National Nuclear Center of the Republic of Kazakhstan (NNC-RK) named EAGLE-3 project. An experiment using molten-alumina as fuel simulant and sodium was conducted at the out-of-pile test facility owned by NNC-RK to investigate sodium cooling effect around the sodium flow regulator on its destruction. The experimental result represented that void development at the initiation of molten-alumina discharge eliminated liquid-phase sodium from the discharge path and this also eliminated sodium cooling effect around the sodium flow regulator. As a result, early destruction of the sodium flow regulator and massive discharge of molten alumina occurred in turn.

JAEA Reports

Operation and management data for the JRR-3 CNS Facility

Suzuki, Masatoshi; Hazawa, Tomoya; Ishizaki, Yoichi*; Obara, Michio*; Inada, Katsutoshi*; Yonekawa, Mitsunori*; Wakita, Hiroshi*

JAERI-Tech 2004-060, 153 Pages, 2004/09

JAERI-Tech-2004-060.pdf:9.78MB

The cold neutron source (CNS) at JRR-3 was constructed for the purpose of improving the utilization performance of the reactor along the lines of upgrade program. There are two methods for extracting cold neutrons from a reactor, one is to filter a small fraction of cold neutrons in the Maxwellian spectrum of reactor neutrons while the other is to increase the fraction of cold neutron by inserting a cryogenic moderator. The latter is adopted as CNS facilities at almost all cases, and liquid hydrogen and its cooling system are equipped with a cold neutron source at many neutron facilities just like JRR-3. Cold neutrons generated in a cold source are extracted through a neutron guide tube, and are utilized for the purpose of neutron beam experiments such as neutron scattering which study the structures of atoms and molecules in the materials and life science fields. This report summarizes the operation data and the main technical issues which were recorded in the whole operation period from commencement date in 1989 to March 2004.

JAEA Reports