Sensitivity and uncertainty analysis of the vessel lower head failure mode and melt release conditions in Nordic BWR using MELCOR code

Galushin, Sergey; Kudinov, Pavel

doi:10.1016/j.anucene.2019.106976

Cited by 6 publications

(18 citation statements)

References 12 publications

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“…The MEM SM is based on the MELCOR code analysis results of vessel failure mode and melt release conditions in Nordic BWR [12,13].…”

Section: Melt Ejection Mode Surrogate Modelmentioning

confidence: 99%

“…Furthermore, in case of gross failure of the vessel LH, it is assumed that all debris in the bottom axial level of the corresponding ring, regardless its state, is discharged linearly over 1 s time-step without taking into account failure opening diameter [10,11]. [13] of vessel failure mode and melt release conditions is performed, in order to provide initial database of full model (FM) solutions for the development of the MEM SM. This step is necessary, since the MELCOR code does not predict directly such parameters as jet radius and jet speed used as initial conditions in the model for assessment of ex-vessel steam explosion loads on the containment (called SEIM SM) in Nordic BWR.…”

Section: Overview Of Nordic Bwr Melcormentioning

confidence: 99%

“…The list of input parameters and respective ranges used to generate the database of MELCOR solutions is presented in Table 1, detailed discussion on parameters selection, and sensitivity of the MELCOR code response to the variability of these parameters can be found in Ref. [12]. The same parameters will be used to develop the MEM SM.…”

Section: Data Base Of Melcor Codementioning

confidence: 99%

“…6-9, we show the results in form of respective CDFs of different MEM SM response quantities generated with random sampling of the MEM SM in ROAAMþ Framework, where n ROAAMþ ¼ 10 5 samples were used. The results are compared to the original MELCOR data distribution (n MELCOR ¼ 2000Þ, obtained with random sampling of MELCOR code [13].…”

Section: Data Base Of Melcor Codementioning

confidence: 99%

“…Steam explosion loads on the containment depend on characteristics of melt release from the vessel, predicted by melt ejection SM [9], based on methods for estimation of leakages and consequences of releases (computer code) (MELCOR) code [10,11] analysis results of vessel failure mode and melt release conditions in Nordic BWR [12].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the Effect of Vessel Failure and Melt Release on Risk of Containment Failure Due to Ex-Vessel Steam Explosion in Nordic Boiling Water Reactor Using ROAAM+ Framework

Galushin

Grishchenko

Kudinov

2020

Journal of Nuclear Engineering and Radiation Science

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Nordic Boiling Water Reactor (BWR) design employs ex-vessel debris coolability in a deep pool of water as a severe accident management strategy. Depending on melt release conditions from the vessel and core-melt coolant interactions, containment integrity can be threatened by formation of non-coolable debris bed, or energetic steam explosion. Melt release from the vessel affect ex-vessel phenomena and is recognized as the major source of uncertainty. The Risk Oriented Accident Analysis Methodology (ROAAM+) is used for quantification of the risk of containment failure in Nordic BWR where Melt Ejection Surrogate Model (MEM SM) provides initial conditions for the analysis of debris agglomeration and ex-vessel steam explosion which determine the respective loads on the containment. MEM SM is based on the system analysis code MELCOR. Modelling of vessel failure and melt release from the vessel in MELCOR is based on parametric models, allowing a user to select different assumptions that effectively control lower head behavior and melt release. The work addresses the effect of epistemic uncertain parameters and modelling assumptions in MEM SM on the containment loads due to ex-vessel steam explosion in Nordic BWR. Sensitivity and uncertainty analysis performed to identify the most influential parameters and uncertainty in the risk of containment failure due to ex-vessel steam explosion. The results of the analysis provide valuable insights regarding the effect of MELCOR models, modelling parameters and sensitivity coefficients on melt release conditions and predictions of ex-vessel steam explosion loads on the containment structures.

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“…The MEM SM is based on the MELCOR code analysis results of vessel failure mode and melt release conditions in Nordic BWR [12,13].…”

Section: Melt Ejection Mode Surrogate Modelmentioning

confidence: 99%

Section: Overview Of Nordic Bwr Melcormentioning

confidence: 99%

Section: Data Base Of Melcor Codementioning

confidence: 99%

Section: Data Base Of Melcor Codementioning

confidence: 99%