Metal Pool Research Articles

Assessing the Lability and Environmental Mobility of Organically Bound Copper by Stable Isotope Dilution.

The environmental mobility of Cu and therefore its potential toxicity are closely linked to its attachment to natural organic matter (NOM). Geochemical models assume full lability of metals bound to NOM, especially under strong oxidizing conditions, which often leads to an overestimation of the lability of soil metals. Stable isotope dilution (SID) has been successfully applied to estimate the labile (isotopically exchangeable) pool of soil metals. However, its application to study the lability of NOM-Cu required development of a robust separation and detection approach so that free Cu ions can be discriminated from (the also soluble) NOM-Cu. We developed a SID protocol (with enriched 65Cu) to quantify the labile pool of NOM-Cu using size exclusion chromatography coupled to a UV detector (for the identification of different NOM molecular weights) and ICP-MS (for 65Cu/63Cu ratio measurement). The Cu isotopic-exchange technique was first characterized and verified using standard NOM (SR-NOM) before applying the developed technique to an "organic-rich" podzol soil extract. The developed protocol indicated that, in contrast to the common knowledge, significant proportions of SR-NOM-Cu (25%) and soil organic-Cu (55%) were not labile, i.e., permanently locked into inaccessible organic structures. These findings need to be considered in defining Cu interactions with the reactive pool of NOM using geochemical models and risk evaluation protocols in which complexed Cu has always been implicitly assumed to be fully labile and exchangeable with free Cu ions.

BWR lower head penetration failure test focusing on eutectic melting

Decommissioning work occasioned by the Fukushima Daiichi Nuclear Power Station (1F) accident of March 2011 is in progress. Severe accident (SA) analysis, testing, and internal investigation are being used to grasp the 1F internal state. A PWR system that refers to the TMI-2 accident is typical for SA codes and testing, on the other hand, a BWR system like 1F is uncommon, understanding the 1F internal state is challenging. The present study conducted the ELSA-1 test, a test that focused on damage from eutectic melting of the liquid metal pool and control rod drive (CRD), to elucidate the lower head (LH) failure mechanism in the 1F accident. The results demonstrated that depending on the condition of the melt pool formed in the lower plenum, a factor of LH boundary failure was due to eutectic melting. In addition, the state related to the CRD structure of 1F unit 2 were estimated.

Study on ultrasonic regulation of the welding performance and defects of 7A52 aluminum alloy plate

The welding performance and defects of thick aluminum alloy plates with medium and high strength are always a hot research topic. In this study, ultrasonic technology was used to regulate the properties and defects of welded joints of a 7A52 aluminum alloy plate during double-sided welding, and these welded joints were compared with conventional welded joints. X rays were used to macroscopically detect the defects of welded joints. An optical microscope was used to analyze the grain structure and microdefects in each zone of welded joints. The tensile and impact tests were carried out on the joints. The fracture morphology of tensile and impact specimens was observed using a scanning electron microscope, and the defects and slag inclusions were analyzed by energy dispersive spectroscopy. In the process of ultrasonic welding, the crystallization process of the molten metal pool was changed, and the solidification and heat transfer environment under ultrasonic influence directly led to the change in the properties and defects of welded joints. The experimental results show that the 7A52 aluminum alloy joints can produce deep penetration and very few macroscopic defects after ultrasonic adjustment. Ultrasonic waves can refine the grains in the weld zone, heat-affected zone, and fusion zone and reduce the microdefects in each zone. The tensile and impact properties of ultrasonic welds have been improved by 84% and 87%, respectively. Therefore, ultrasonic waves can regulate the welding performance and defects of 7A52 aluminum alloy plates and other aluminum alloy plates with a similar structural composition. This study provides guidance for the selection of a double-sided welding method with low cost, high efficiency, and good joint performance for aluminum alloy plates.

Effects of Alternating Magnetic Field on the Hot Tearing Susceptibility and Microstructure of Al-5Cu Alloy

The influence of alternating magnetic field on hot tearing susceptibility (HTS) and microstructure of Al-5Cu alloy were studied using hot tearing test system and differential thermal analysis test. The Clyne-Davies model was used to evaluate the HTS of the alloy quantitatively under different magnetic current intensities (0A, 5A, 10A, 15A). The experimental results show that the HTS and microstructure of Al-5Cu alloy can be affected by imposing the alternating magnetic field during alloy solidification. In the range of 0–10A, with the increase of alternating magnetic field current intensity, there is strong forced convection in the molten metallic pool under the action of electromagnetic force, which leads to the fragmentation of dendrites and the grains refinement, optimizes the feeding channels between grains and reduces the HTS of the alloy. When the alternating magnetic field intensity is 15A, the grains become coarser due to the thermal effect of electromagnetic field, resulting in the deterioration of the feeding channel and the increase of HTS.

Numerical Simulations of the Molten Metal Droplet Formation in the Electroslag Remelting Process with a Rotating Electrode

Electroslag remelting (ESR) is a well‐known process widely used in the production chain of high‐quality alloys. Herein, numerical investigations of the implementation of a rotating‐electrode (low rotation speed) modification to the flow behavior inside the slag area of a lab‐sized ESR process are shown. Therefore, a coupled simulation approach between a commercial CFD (FVM) and electromagnetics (FEM) software is used. Comparative results for the simulated droplet formation between a stationary and a rotating electrode are shown. The results show a strong effect on the local shaping of the liquid metal film below the electrode and consequently a radial shift of the droplet incidence into the metal pool under electrode rotation. There are no observable positive effects on mean metal film thickness, droplet trajectory, or droplet size, which are suspected as possible explanations for observed material improvements in small‐scale rotating electrode ESR processes. In addition, an overview of current bottlenecks, restrictions, and possible strategies for improved ESR process simulations is given.

Droplet spatter suppression in laser lap welding of galvanized sheets using additional coaxial annular laser source

This study is to prevent droplet spatter in laser welding of galvanized sheets. Three-dimensional welding simulation model is also established and analyzed to reveal the relationship between keyhole oscillation and flow behavior. It is found major reason for droplet spatter is the impact force of the reflux and eddy of the metal pool toward the keyhole. Keyhole oscillates seriously and reflux impact causes energy exchange discontinuity, making the keyhole opening intermittent closed in traditional Gaussian laser source alone. While certain output proportion of coaxial annular and Gaussian laser source could considerably improve impact resistance on the reflux and suppress droplet spatter obviously. Weld appearance is relatively beautiful and harmonious, with few undercuts, collapses and humps.

Биогеохимическая характеристика корнеобитаемого слоя травянистых растений на рекультивированных участках техногенных отходов

The introduction of the work substantiates the relevance of studying the biogeochemistry of the root layer of herbaceous plants growing on man-made waste from coal mining and iron ore enrichment after 40 years of reclamation. The main part of the report is devoted to the results of determining the gross content of heavy metals and metalloids, Sorg., residual toxicity, occurrence and growth characteristics of the bacterium Azotobacter chroococcum in embryos and background soil under similar plants. It is shown that during the long-term development of embryosems on waste of different origin, a high pool of heavy metals and metals is preserved in them, and Sorghum accumulates. In the area of coal mining around the roots of the clover, the maximum concentrations of Pb are detected, while cereals - Br. On the forested tails of the iron ore agglomeration, the trend is different: Ca, Ni, Cu, Mn, Zn are concentrated around the roots of cereals, and As is near the roots of the clover. However, the residual toxicity is manifested only on the tailings of the iron ore agglomeration. It has been established that the occurrence of azotobacter in the root layer of different plants is ubiquitous, but in the embryos of the forested tailings pond, the bacterial populations are heterogeneous, they contain donkey strains showing luminescence, rhizoid growth type and antagonism. Around the roots of the clover, conditions were formed that were less favorable for reproduction than under cereals. The data obtained expand knowledge about the role of phytobiomes in the migration of chemical elements at man-made facilities, can be taken into account when developing toxicity neutralization and in predicting the effectiveness of biological reclamation.

Transient thermal analysis of laser beam welding of titanium alloy sheet

Melting and evaporation occur when the laser beam falls on the surface of the material. A pool of molten metal forms at the interface of two materials in the laser welding process. In general there are two methods for the laser welding process. This work discusses the transient thermal analysis of laser beam welding of titanium alloy thin sheets. The main point of discussion is the effect of heat on the temperature field over different time frames. Compared to other lasers, Nd-YAG laser is gaining increasing focus among lasers because of its exceptional feature. Conduction mode and keyhole mode are the two modes of lase welding process. Out of that keyhole mode is used for thick material with high power density and conduction mode is used for low thickness with low power density. In this report laser beam having fibre diameter 0.6 mm is taken as a constant flux moving heat source which was focused on two Titanium alloy (Ti-6Al-4V) plates of thickness 1 mm placed in contact with each other. Temperature distribution at different interval of time and ‘heat affected zone’ (HAZ) were determined using ANSYS.

Friction stir processing of nanofiller assisted AISI 1010 steel-CDA 101 copper dissimilar welds: a strength factor approach

In this research study the effects of adding nano fillers such as SiO2, graphene nanoplatelets (Gnps) and biochar on to the weld pool of dissimilar AISI-SAE 1010 Steel- CDA 101 copper were investigated. The main aim of this research study was to investigate the effect of adding ceramic and carbon rich secondary reinforcements on to the friction stir weld (FSW) pool of dissimilar metals and its relative outcomes. The mechanical properties such as tensile strength, yield strength, % of elongation, hardness and fatigue strength were investigated in the form of the strength factor approach. According to the results, the highest strength factor of 98 was obtained for welds made using Gnps of about 1.0 wt.% with constant axial load of 5 kN, traverse speed of 30 mm/min, rotational speed of 900 rpm, dwell time of 5 s and plunging depth of 0.2 mm. The highest tensile strength of 225 MPa and a fatigue strength of 168 MPa was noted for the weld using 2 wt.% Gnps in the weld pool. However, the biochar addition of 2.0 wt.% on to the weld bead positioned the second highest strength factor of 88 due to its solid lubricity. In all the welding processes, large doses of fillers produced undesirable strength factor values. The microstructure of both the weld and tool shows desirable effects for nanoparticle assisted welds. The HAZ and TMAZ grains were refined due to the inclusion of the nanoparticles. The result shows that naturally acquired biochar nanoparticles have the potential of replacing high cost nanofillers in joining metals with more than 85% close to the high cost fillers for the same output. These properties improved dissimilar copper-steel welded plate joints that could be used in automotive, defence, aerospace and structural applications.

A brief review on the manufacturing of metal components using selective laser melting

Technologies relevant to additive based fabrication are gaining global attention owing to the massive escalation in the requirement towards materials with enhanced performance possessing intricate shapes and geometrical structures. Unique features of these additive based fabrication techniques includes, their ability to fabricate three dimensional structures with almost complete structures with requirement of very minimized after processing techniques and the immediate employability of the fabricated parts for their intended real time usage etc. Falling under the category of powder bed based fusion methodologies, the selective laser melting (SLM) is one of the most widely employed additive based fabrication technique. SLM technique, as referred by its name, employs a beam of laser to melt and to fuse the powders of metal together. SLM possess the ability to fabricate components with any nature of intricate geometry, by means of an additive based layer–by–layer scanning approach. Technique of SLM not only permits wider flexibility in fabrication of parts and components with complex structures, but also makes it possible to fabricate parts with completely refined micro-structures and meta-stable phases and this is possible due to the adoption of extreme rates of cooling and minimized pool of metal. However, in order to employ the technique to SLM to various industrial sectors, there exists a vital need for understanding the impact of its several relevant parameters and their role in influencing the dimensional accuracy and properties of the fabricated parts. So, this review paper records and describes the experimental findings of several researchers during their research work on employment of fabrication of Al, Ti, Ni, Co based components using the technique of SLM.

Soil Acidification, Mineral Neoformation and Heavy Metal Contamination Driven by Weathering of Sulphide Wastes in a Ramsar Wetland

Past waste disposal practices have left large volumes of sulphidic material stockpiled in a Ramsar wetland site on the Atlantic coast of southwestern Spain, leading to severe land degradation. With the aim of addressing this legacy issue, soil core samples were collected along two transects extending from the abandoned stockpiles to the adjacent marshland and subjected to XRD, SEM-EDS, ICP-OES and ICP-MS analyses. Sulphide oxidation has been shown to be a major driver of acid generation and metal leaching into the environment. The marsh soil receiving acid discharges from the sulphide wastes contains elevated levels (in mg kg−1) of Pb (up to 9838), As (up to 1538), Zn (up to 1486), Cu (up to 705), Sb (up to 225) and Tl (up to 13), which are retained both in relatively insoluble secondary minerals (mainly metal sulphates and oxides) and in easily soluble hydrated salts that serve as a transitory pool of acidity and available metals. By using a number of enrichment calculation methods that relate the metal concentrations in soil and their baseline concentrations and regulatory thresholds, there is enough evidence to conclude that these pollutants may pose an unacceptable risk to human and ecological receptors.

Morphology tailoring of metal pool and eutectic carbides in magnetic-controlled electroslag remelted M2 high-speed steel

A transverse static magnetic field (TSMF) was superimposed during electroslag remelting (ESR) process to regulate the shape of metal pool, the eutectic carbides morphology as well as the mechanical properties of electroslag remelted M2 high-speed steel (HSS) in current study. The metal pool became shallower and flatter after applying a 65 mT TSMF. Moreover, refined eutectic carbides and solidification structure (tended to grow axial) of the ESR ingot were obtained, together with uniform/improved mechanical properties (hardness, wear). Modifications of the morphology of metal pool and grain growth angle under the TSMF were attributed to a periodic electromagnetic excitation effect on droplets transition characteristics, which changed the drop path of the droplets (single to multiple drop) and homogenized the temperature distribution in metal pool. In addition, local solidification time (LST) became shorter and the number of inclusions ((Ti, V)N–Al2O3 and (Ti, V)N) which acted as heterogeneous nuclei for eutectic carbides formation increased (the inclusions also became finer) due to TSMF, resulting in the refinement of the eutectic carbides in ESR ingots.

Bioaccumulation and release of heavy metals during growth and decomposition of cultivated Gracilaria lemaneiformis

Seaweeds are important primary producers and bioremediation materials, but its litter produced during growth and harvest is one of the restrictions to the sustainable development of seaweed cultivation. In this study, we conducted field investigation and indoor experiments to analyze the bioaccumulation and release of metals in Gracilaria lemaneiformis during the growth and decaying. The investigation revealed the 3.5 × 105 t (wet weight) G. lemaneiformis from a 1500 ha cultivation area bioaccumulated 1925–2353 kg Zn, 233.5–251 kg Cu, 70.5–80.5 kg Pb and 25.5–47 kg Cd, indicating that G. lemaneiformis is a good metals remover. The growth and decaying period of G. lemaneiformis releases, absorbs or adsorbs metals. It has the function of a “heavy metal pool”, simultaneously accumulate and release metals. G. lemaneiformis has a strong influence on heavy metals cycling in the seaweed cultivation ecosystem and provides a very good sample for biogeochemistry study for the globally seaweed sustainable development.

Coordinated design of the cartridge-type blanket and the ceramic pebble divertor for the helical reactor FFHR-b3

The cartridge-type blanket for the helical reactor has been updated and named the CARDISTRY-B3. Together with this, the ceramic pebble ergodic limiter/divertor system named the REVOLVER-D3 has been adopted in the design. There was a difficulty in fabricating the blanket cartridges due to the first wall shape with three-dimensional surface. This difficulty has been removed by introducing the slit first wall, where the first wall surface is formed by alternately stacking solid metal plates and porous plates made of metal or ceramic. The liquid metal flowing inside the blanket cartridge oozes out through the porous plates and forms the surface flow covering the first wall. Solid target plates for the helical divertor has been omitted, because the divertor region is already covered and protected by the liquid metal surface flow. The liquid metal freely falls inside the blanket cartridges by the gravity force and then exhausted to the pool set on the lower port. The ceramic pebbles, which are dropped to the inboard-side ergodic layer to form the flowing limiter divertor, also flow into the liquid metal pool. The pebbles and liquid metal are individually elevated again by screw conveyers. Since the free surface of the liquid metal is exposed to the plasma, the vapor pressure of the working liquid metal should be low enough. Ternary or quadruple alloys, which include Li, Sn, Pb (or Bi), and Er, have been selected as the candidates of the functional liquid metal for the CARDISTRY-B3 that satisfies the requirements of low vapor pressure, low density, low melting point, and high tritium breeding ratio. In this study, the coordinated design of CARDISTRY-B3 and REVOLVER-D3 for the FFHR-b3 is presented. The FFHR-b3 is one of the design options that aims at demonstration of 100 MW net electricity with two times larger devise size than LHD.

Natural convection phenomena in a liquid metal pool due to relocated and heap of heat-generating core debris: Numerical study

In the present numerical study, authors have investigated the natural convection heat transfer and fluid flow characteristics in a pool due to the heat generating core debris, i.e. decay heat in a typical fast breeder reactor. Two significant aspects of decay heat removal from debris under core disruptive accidents have been analyzed. These key aspects are (i) relocation of heat-generating core debris at the different locations inside the main vessel and (ii) effect of debris heap on heat transfer from source to ambient. These cases are analyzed extensively on full-scale three-dimensional reactor model with all major components. Multiple tray-type core catcher has incorporated with passive pipes over one collection tray. The present numerical study provides a robust and practical feasible core debris retention arrangement after a severe accident in fast breeder reactors. Also, the study is focused on a feasible array of core collection trays that maintained heat-generating debris and heat shield trays under safe thermal designed limit (∼1200 K for debris and ∼ 923 K for trays). This eliminates the further advancement of accidents and leakage of radioactive material into environments. During our analysis, it has been found that single tray with passive pipes maintained the heat-generating debris and tray under safe thermal limit for a fraction of 50 % destroyed core relocated to lower plenum while remaining heat-generating debris is present in its original position. Multiple tray arrangements accommodate the whole core debris within safe thermal design limits. With the possibility of debris heap after its relocation to the lower plenum, it has been found that heap angle less than 3° does not affect the integrity of core catcher.

Evolution of Y2O3 dispersoids during laser powder bed fusion of oxide dispersion strengthened Ni-Cr-Al-Ti γ/γ’ superalloy

The successful synthesis of oxide-dispersion-strengthened (ODS) alloys via laser powder bed fusion ( L -PBF) requires a better understanding of the interaction of the oxide dispersoids with the metallic melt pool. Here, a γ/γ’-strengthened Ni-8Cr-5.5Al-1Ti (wt%) model alloy is studied, as a simplified version of the commercial CM247LC alloy, by melting pre-alloyed powders in which 0.5–1 wt% Y 2 O 3 nanoparticles were added via mechanical alloying. The Y 2 O 3 nanoparticles follow three distinct paths. First, the strong affinity between Y 2 O 3 and Al leads to the formation of Y 4 Al 2 O 9 slag which floats on the melt pool; if in excess, the slag leads to vertically aligned mm-size cavities, preventing complete consolidation of the alloy. Second, a high number density of oxide nanodispersoids is distributed within the alloy’s grain inducing a strong (100) texture and noticeably reduces grain size compared to the unmodified base alloy. Third, despite the high stability of Y 2 O 3 , the extreme temperatures achieved in the melt pool decompose some of the Y 2 O 3 precipitates leading to the formation of Ni- and Y-rich particles (16 nm in radius) and Y segregation to the alloy’s grain boundaries. The local composition on cracked grain boundaries is consistent with Ni 17 Y 2 having an embrittling and liquation effect. Based on these results, the critical role of Al in reacting with oxide nanodispersoids during L -PBF manufacturing is discussed, and various types of potentially more successful dispersoids are suggested. Powders of a Ni-8Cr-5.5Al-1Ti (wt%) model superalloy containing 0.5–1 wt% Y 2 O 3 nanodispersoids are melted via laser powder bed fusion. The Y 2 O 3 addition leads to various microstructural changes. The columnar grain structure is refined and a strong (100) texture is observed. Some Y 2 O 3 undergoes partial dissolution/reaction in the melt pool, despite being one of the most stable dispersoids conventionally used in powder metallurgy processed ODS alloys. The resulting free Y leads to significant grain boundary segregation with an embrittling effect, and the formation of Ni-Y-rich nanodispersoids throughout the alloy. Y 2 O 3 nanodisperoids that are not reduced are either incorporated directly into the matrix or scavenge S and form Y-O-S dispersoids. A fraction of the added oxide is not incorporated but reacts with Al to form Y 4 Al 2 O 9 slag, a reaction which is influenced by the energy density employed during the LPBF processing.

Role of Electrode Rotation on Improvement of Metal Pool Profile in Electroslag Remelting Process

A comprehensive transient model is developed to study the effect of electrode rotation on the evolution of metal pool profiles and the solidification quality of ESR ingots. Magnetohydrodynamic flow, heat transfer, solidification, and electrode melting are considered simultaneously in the model. The growth of the ESR ingot is predicted using the dynamic layering method. The numerical results show that the productivity reaches a maximum of 15.97% at the rotating speed of 40 rpm without increasing power. With the increasing rotating speed, the maximum temperature of the melt decreases, and the temperature distribution becomes more uniform. Compared with the static one, the pool profiles are flattened by −1.19%, −8.52%, and 12.44% at the rotating speeds of 20, 40, and 60 rpm, respectively. The metal pool profile was improved remarkably, but only at the higher speed (i.e., 60 rpm). The effect of rotating speed on the metal pool profile depends on the competition between the melting rate and slag temperature. Meanwhile, the local solidification time and the secondary dendrite arm spacing are slightly improved at lower rotating speeds but are significantly worse at higher rotating speeds.

Effect of different conditions on heat transfer characteristics of molten Zr-Stainless steel pool with water injection

External Reactor Vessel Cooling (ERVC) could be accompanied by the in-vessel water injection to alleviate the thermal focusing effect of the light metallic layer and enhance the In-Vessel Retention (IVR) strategy. Through the wATer injectiOn on molten Zirconium-Stainless steel Metallic pool experiment (ATOM), the effects of different temperatures, mass flow rates of water injection, and different mass percentages of Zr on the heat transfer characteristics after water injection have been investigated. The mass flow rate of water injection ranges from 0.05 kg/s to 0.10 kg/s, and the mass percentage of Zr ranges from 13% to 60%. Eight tests were carried out, and the maximum upward heat flux removed from the melt surface ranged from around 800 to 1400 kW/m2. A higher water injection mass flow rate and a lower Zr mass percentage could lead to a higher steam generation rate. After water injection, the experimental melt temperature and concentration factor decrease. By applying the ATOM heat transfer coefficient as the input data in the nuclear reactor case, the calculated results indicate that the thermal focusing effect inducing by the decrease of the light metallic layer’s height could be highly mitigated by water injection. As a result, the integrity of the RPV could be enhanced. During the whole experiment for all the tests, no vapor explosion and melt ejection were found.

Processes and mechanisms of phosphorus mobility among sediment, water, and cyanobacteria under hydrodynamic conditions.

Phosphorus (P) has an important role in eutrophication and it is essential to explore the processes and mechanisms of P mobility in natural waters. In this study, laboratory experiments were conducted to simulate the SW system (sediment and water) and SAW system (sediment, algae, and water) under four hydrodynamic intensity conditions (static control, 50 rpm, 125 rpm, and 200 rpm treatments), to investigate P mobility. Results in SW system showed that sediment was an important source of P for overlying water, and the released total P (TP) increased with stronger hydrodynamic intensity, when P associated with metal pools (redox-sensitive P [BD-P] and meta-oxides bound P [NaOH-P]) were the most unstable and easier to migrate into the overlying water. Stronger hydrodynamic disturbances could enhance the processes including sediment resuspension, dissolution of particles, and release of P, when P mobility had a close relationship with redox conditions near sediment-water interface (SWI). Therefore, the release of TP, BD-P, and NaOH-P from sediment increased and decreased in the control and 50-200 rpm treatments over time. In SAW system, the release of TP significantly increased from sediment comparing to SW system, and the growth of Microcystis aeruginosa could selectively enhance the release of BD-P, NaOH-P, and organic P (OP). Meanwhile, the released P from sediment was quickly accumulated by algal cells. The maximum accumulation ability of P by cells, the highest photosynthetic efficiency, and the best growth of M. aeruginosa were observed in 125 rpm treatment. But with excessively strong hydrodynamic intensity (200 rpm treatment), the accumulation ability of P and alkaline phosphatase activity (APA) of M. aeruginosa was suppressed, which might hinder algal utilization of P and inhibit algal growth. Overall, our findings demonstrated the patterns of P mobility in natural ecosystems and could contribute to the understanding of P cycling.

Material Interactions in Severe Accidents – Benchmarking the MELCOR V2.2 Eutectics Model for a BWR-3 Mark-I Station Blackout: Part II – Uncertainty Analysis

Single case comparisons between severe accident simulations can provide detailed insights into severe accident model behavior, however, they cannot offer insights into model uncertainty, sensitivity to uncertain parameters, or underlying model biases. In this analysis, the single case benchmark comparison of the MELCOR material interaction models for a station blackout (SBO) scenario of a boiling water reactor (BWR) using representative Fukushima Daiichi Unit 1 boundary conditions is expanded to include an uncertainty analysis. As part of this uncertainty analysis, 1200 simulations are performed for each material interaction model (2400 total), with random sampling of 14 uncertain MELCOR input parameters. Input parameters are selected for their impact on models representing core degradation processes. These include candling, fuel rod failure, debris quenching and dryout. The analysis performed here is not a traditional “best-estimate” uncertainty analysis that uses best-estimate parameters or identifies best-estimate figure of merit distributions. Instead, it is an exploratory uncertainty analysis that identifies and interrogates underlying model form biases of the two material interaction models (eutectics and interactive materials models). Uniform distributions are applied to all uncertain parameters to ensure coverage of the model parameter uncertainty space. Key findings from this study include underlying model form biases exhibited by material interaction models, and notable differences in accident progression outcomes between the material interaction models. This uncertainty study extends and confirms the conclusions from the first part of this study, which compared the impact of material interaction modeling on simulation of a short-term station blackout scenario with representative Fukushima Daiichi Unit I boundary conditions. In particular, this study confirms that the eutectics model generally exhibits accelerated degradation and failure of fuel components, the core plate, and the lower head. The eutectics model also has a tendency to exhibit a greater degree of core degradation, greater debris mass formation, and larger debris mass ejection. Finally, the eutectics model exhibits higher maximum temperatures for fuel, cladding, particulate debris, oxidic molten pool, and metallic molten pool components than the interactive materials model; interactive materials model simulations exhibit a soft “limitation” on maximum temperatures that is related to the temperature at which material relocation occurs.