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Safety analysis and code development for nuclear fuel cycle facilities

Abstract

We are estimating that the debris containing fuel are piled in the containment and the pressure vessel bottoms of Fukushima-Daiichi NPPs. A radioactive Xe concentration discharged in recriticality is being monitored by utilizing the gas management system set up in NPPs unit 1-3. For this reason, we can confirm the recriticality might not be broken out. However, the debris conditions distributed in the containment vessel and the pressure vessel bottoms are not clear. The internal and external surrounding changes will make recriticality become possible. According to TEPCO's roadmap, TEPCO will launch extracting task within 10 years. Even in the case that the fuel condition changes due to debris relocation and mixture, subcriticality must be secured. Criticality safety analysis with non-uniform effect should therefore be essential for the molten debris. For above reasons, we studies the optimum distributions with some parameters that have a large reactivity change were assessed with OPT-DANT code. Finally, the boron concentration was estimated in order to keep subcriticality. (author)
Publication Date:
Aug 15, 2013
Product Type:
Technical Report
Report Number:
JNES-RE-2013-0001
Resource Relation:
Other Information: 5 refs., 5 figs.; This record replaces 46076312; Related Information: In: Annual safety research report, JFY 2012| Japan Nuclear Energy Safety Organization, Tokyo (Japan)| 708 p.
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; CORIUM; CRITICALITY; FISSION PRODUCTS; FUEL CYCLE CENTERS; FUEL REPROCESSING PLANTS; FUKUSHIMA-1 REACTOR; FUKUSHIMA-2 REACTOR; FUKUSHIMA-3 REACTOR; MELTDOWN; NUCLEAR POWER PLANTS; O CODES; REACTIVITY; SAFETY ANALYSIS
OSTI ID:
22370945
Research Organizations:
Japan Nuclear Energy Safety Organization, Nuclear Fuel Cycle and Radioactive Waste Management Safety Department, Tokyo (Japan)
Country of Origin:
Japan
Language:
Japanese
Other Identifying Numbers:
TRN: JP1501988076312
Availability:
Available from the Internet at URL http://www.nsr.go.jp/archive/jnes/content/000125907.pdf
Submitting Site:
INIS
Size:
page(s) 249-254
Announcement Date:
Aug 05, 2015

Citation Formats

None. Safety analysis and code development for nuclear fuel cycle facilities. Japan: N. p., 2013. Web.
None. Safety analysis and code development for nuclear fuel cycle facilities. Japan.
None. 2013. "Safety analysis and code development for nuclear fuel cycle facilities." Japan.
@misc{etde_22370945,
title = {Safety analysis and code development for nuclear fuel cycle facilities}
author = {None}
abstractNote = {We are estimating that the debris containing fuel are piled in the containment and the pressure vessel bottoms of Fukushima-Daiichi NPPs. A radioactive Xe concentration discharged in recriticality is being monitored by utilizing the gas management system set up in NPPs unit 1-3. For this reason, we can confirm the recriticality might not be broken out. However, the debris conditions distributed in the containment vessel and the pressure vessel bottoms are not clear. The internal and external surrounding changes will make recriticality become possible. According to TEPCO's roadmap, TEPCO will launch extracting task within 10 years. Even in the case that the fuel condition changes due to debris relocation and mixture, subcriticality must be secured. Criticality safety analysis with non-uniform effect should therefore be essential for the molten debris. For above reasons, we studies the optimum distributions with some parameters that have a large reactivity change were assessed with OPT-DANT code. Finally, the boron concentration was estimated in order to keep subcriticality. (author)}
place = {Japan}
year = {2013}
month = {Aug}
}