Fusion Safety Research Articles

Evaluation of the Fusion Rate and Safety of Escherichia coli-Derived rhBMP-2 in Transforaminal Lumbar Interbody Fusion for Patients with Degenerative Lumbar Disease: A Prospective, Multicenter, Single-Arm Trial.

Background: Few studies have documented the viability of E. coli-derived recombinant human bone morphogenetic protein-2 (rhBMP-2) in transforaminal lumbar interbody fusion (TLIF). This study aimed to assess the safety and fusion rate of rhBMP-2 in TLIF. Methods: The study was conducted as a prospective, multicenter, single-arm trial, and 30 patients needing one- or two-level TLIF were enrolled. Fusion rate was assessed using the 12-month interbody fusion rate on CT. Postoperative problems, including seroma, radiculitis, and ectopic bone formation, which have been documented as risks associated with rhBMP-2 in prior studies, were recorded. Results: The study demonstrated fusion outcomes in all instances at 52 and 104 weeks post-surgery. Significant improvements were observed in clinical outcomes, with ODI, SF-36, and VAS scores, all achieving statistical significance (p < 0.0001). No perioperative adverse events requiring reoperation were reported, and there were no incidences of seroma, radiculitis, cage migration, grafted bone extrusion, postoperative neurologic deficit, or deep wound infection. Conclusions: The study demonstrates the high safety and efficacy in inducing bone fusion of E. coli-derived rhBMP-2 in TLIF, with a notable absence of adverse postoperative complications. Trial registration: This study protocol was registered at Korea Clinical Research Information Service (number identifier: KCT0004738) on July 2020.

Human Multi-Chimeric Cell (HMCC) Therapy as a Novel Approach for Tolerance Induction in Transplantation

Cellular therapies are regarded as the most promising approach for inducing transplant tolerance without life-long immunosuppression in solid organ and vascularized composite allotransplantation (VCA). Currently, no therapies are achieving this goal. This study introduces a novel Human Multi-Chimeric Cell (HMCC) line created by fusion of umbilical cord blood (UCB) cells, from three unrelated donors as an alternative therapeutic approach to bone marrow transplantation and tolerance induction in solid organ and VCA transplants. We performed eighteen ex vivo polyethylene glycol mediated fusions of human UCB cells from three unrelated donors to create HMCC. Mononuclear cells labeled with PKH26, PKH67, and eFluor™ 670 fluorescent dyes were fused and sorted creating a new population of triple-labeled (PKH26/PKH67/eFluor™ 670) HMCC. The creation of HMCC from three unrelated human UCB donors was confirmed by flow cytometry and confocal microscopy. Genotyping analyses determined the tri-chimeric state of HMCC by presence of parent alleles and selected loci specific for each of three UCB donors. Phenotype characterization confirmed hematopoietic markers distribution, comparable to UCB donors. HMCC maintained viability and displayed a low apoptosis level. The COMET assay revealed absence of genotoxicity, confirming fusion safety. Colony forming units assay showed clonogenic properties of HMCC. This study confirmed the feasibility of HMCC creation from three unrelated human UCB donors and characterized tri-chimeric state, hematopoietic phenotype, viability, safety, and clonogenic properties of HMCC. The created HMCC line, representing genotype characteristics of three unrelated human UCB donors, introduces a novel therapeutic approach for bone marrow, solid organ, and VCA transplants.Graphical

Current status of MELCOR 2.2 for fusion safety analyses

MELCOR is an integral code developed by Sandia National Laboratories (SNL) for the US Nuclear Regulatory Commission (USNRC) to perform severe accident analyses of Light Water Reactors (LWR). More recently, MELCOR capabilities are being extended also to analyze non-LWR fission technologies. Within the European MELCOR User Group (EMUG), organized in the framework of USNRC Cooperative Severe Accident Research Program (CSARP), an activity on the evaluation of the applicability of MELCOR 2.2 for fusion safety analyses has been launched and it has been coordinated by ENEA. The aim of the activity was to identify the physical models to be possibly implemented in MELCOR 2.2 necessary for fusion safety analyses, and to check if those models are already available in MELCOR 1.8.6 for fusion version, developed by Idaho National Laboratory (INL). From this activity, a list of modeling needs emerged from the safety analyses of fusion-related installations have been identified and described. Then, the importance of the various needs, intended as the priority for model implementation in the MELCOR 2.2 code, has been evaluated according to the technical expert judgement of the authors. In the present paper, the identified modeling needs are discussed. The ultimate goal would be to propose to have a single integrated MELCOR 2.2 code release capable to cover both fission and fusion applications.

A Human-Robot Dynamic Fusion Safety Algorithm for Collaborative Operations of Cobots

A Human-Robot Dynamic Fusion Safety Algorithm for Collaborative Operations of Cobots

Experimental Investigation of a Helium-Cooled Breeding Blanket First Wall under LOFA Conditions and Pre-Test and Post-Test Numerical Analysis

The experimental investigation of a prototypical set-up simulating a loss of flow accident in a helium-cooled breeding blanket first wall mock-up under typical heat load conditions is presented. The experimental campaign reproduces the expected DEMO thermal-hydraulics conditions during normal and off-normal situations and aims at providing some insight into the fast transients associated with the loss of flow in the blanket first wall. The experimental set-up and the definition of the experimental matrix are discussed, including pre-test analysis performed in support of these activities. The major experimental results are discussed, and a procedure of using the acquired data for validating and calibrating the RELAP-3D model of the mock-up is introduced. All these activities contributed to the creation of a relevant theoretical and practical experience that can be used in further studies concerning incidental transients in real-plant scenarios in the framework of DEMO plant fusion safety activities.

Разработка пористых титановых имплантатов для межтелового спондилодеза

Relevance Application of 3D printing using the method of selective laser fusion for production of intervertebral cages is a topical trend of the spinal surgery. Purpose Assessment of the efficiency and safety of original interbody fusion implant application made of titanium alloy according to 3D printing technology with selective laser fusion. Materials and methods The original flattened bean-shaped cages, with an integral side part and an internal configuration in the shape of three-dimensional 1.5 × 1.8 mm porous lattice were tested . The products were made of Ti6Al4V powder using 3D printing technology with selective laser fusion. Post-processing of the products surface included abrasive blast cleaning using the SLA method and sterilization with ethylene oxide. Experiments on modeling interbody fusion with replacement of intervertebral discs with cages at levels L4 – L5 and L5 – L6 were performed in 8 mongrels. Additional primary stabilization of the lumbar spine was produced with an external fixator within 30 days after implantation. The total follow-up period lasted 180 days. Radiography, scanning electron microscopy, roentgenospectral and biochemical analysis methods were applied. Results X-ray examination demonstrated the contact between the frontal surfaces of the cages and the bone tissue of the vertebral bodies and the development of fusion in all experimental animals. Biochemical analysis did not reveal the signs of intoxication, indicating the danger of the products application. The microrelief of the implants was characterized by microroughness ranged from 1to 50 μm. In the surface layer of products, in addition to the elements of titanium, aluminum and vanadium, the carbon, oxygen, silicon, trace amounts of other organic and inorganic elements were found. Newly formed bone trabeculae were macroscopically and submicroscopically visualized in the sawcuts of bone blocks in the porous lattice of the internal part of the implants. Conclusions Experimental testing of porous implants made of titanium alloy using selective laser fusion has shown their effectiveness in obtaining interbody fusion and acceptable safety.

Lumbar Interbody Fusion Conducted on a Porcine Model with a Bioresorbable Ceramic/Biopolymer Hybrid Implant Enriched with Hyperstable Fibroblast Growth Factor 2.

Many growth factors have been studied as additives accelerating lumbar fusion rates in different animal models. However, their low hydrolytic and thermal stability both in vitro and in vivo limits their workability and use. In the proposed work, a stabilized vasculogenic and prohealing fibroblast growth factor-2 (FGF2-STAB®) exhibiting a functional half-life in vitro at 37 °C more than 20 days was applied for lumbar fusion in combination with a bioresorbable scaffold on porcine models. An experimental animal study was designed to investigate the intervertebral fusion efficiency and safety of a bioresorbable ceramic/biopolymer hybrid implant enriched with FGF2-STAB® in comparison with a tricortical bone autograft used as a gold standard. Twenty-four experimental pigs underwent L2/3 discectomy with implantation of either the tricortical iliac crest bone autograft or the bioresorbable hybrid implant (BHI) followed by lateral intervertebral fixation. The quality of spinal fusion was assessed by micro-computed tomography (micro-CT), biomechanical testing, and histological examination at both 8 and 16 weeks after the surgery. While 8 weeks after implantation, micro-CT analysis demonstrated similar fusion quality in both groups, in contrast, spines with BHI involving inorganic hydroxyapatite and tricalcium phosphate along with organic collagen, oxidized cellulose, and FGF2- STAB® showed a significant increase in a fusion quality in comparison to the autograft group 16 weeks post-surgery (p = 0.023). Biomechanical testing revealed significantly higher stiffness of spines treated with the bioresorbable hybrid implant group compared to the autograft group (p < 0.05). Whilst histomorphological evaluation showed significant progression of new bone formation in the BHI group besides non-union and fibrocartilage tissue formed in the autograft group. Significant osteoinductive effects of BHI based on bioceramics, collagen, oxidized cellulose, and FGF2-STAB® could improve outcomes in spinal fusion surgery and bone tissue regeneration.

The utility of 'home-made' reagent red blood cells for antibody screening during pre-transfusion compatibility testing in Uganda.

The WHO recommends that pre-transfusion testing should include ABO/RhD grouping followed by screening for red blood cell (RBC) alloantibodies using the indirect antiglobulin test (IAT). However, in Uganda, current practice does not include RBC alloantibody screening. To assess the utility of 'home-made' reagent RBCs in alloantibody screening. In a laboratory-based study, group O RhD positive volunteer donors were recruited and their extended phenotype performed for C, c, E, e, K, Fya, Fyb Jkb, S and s antigens. These 'home-made' reagent RBCs were preserved using Alsever's solution and alloantibody detection tests performed. For quality assurance, repeat alloantibody screening of patients' samples was done at Bloodworks Northwest Laboratory in Seattle, United States. A total of 36 group O RhD positive individuals were recruited as reagent RBC donors (median age, 25 years; range, 21 - 58 years; male-to-female ratio, 1.6:1). Out of the 311 IATs performed, 32 (10.3%) were positive. Confirmatory IAT testing in the United States was in agreement with the findings in Uganda. Use of 'home-made' reagent RBCs during pre-transfusion testing in Uganda is feasible. We recommend the introduction of pre-transfusion IAT alloantibody screening in Uganda using 'home-made' reagent RBCs to improve transfusion safety.

Post-test analysis of Series D experiments in LIFUS5/Mod3 facility for SIMMER code validation of WCLL-BB In-box LOCA

The In-box LOCA for the WCLL-BB is recognized as a Design Basis Accident (DBA) and is of substantial interest to the DEMOnestration reactor design, therefore, the transient response of such an accident must be carefully investigated and addressed to ensure the safe operation and integrity of the whole system. In this way, the LIFUS5/Mod3 test facility (constructed at ENEA Brasimone Research Center) has been upgraded in the period 2018–2020 to perform a series of tests. The first set of the tests were named Series D, which are characterized by injecting specified amounts of pressurized water into the Lithium lead liquid bulk. The experimental campaign aimed at validating and qualifying the SIMMER-III code as a reliable numerical tool for the safety studies of the WCLL BB.In parallel with performing the tests, SIMMER-III Verification and Validation (V&V) was conducted according to a standard code validation procedure. SIMMER-III is a two-dimensional, multiphase, multicomponent, Eulerian, fluid-dynamics code which was firstly developed at the Japan Nuclear Cycle Development Institute (JNC). An adopted version of the original SIMMER-III code so-called Ver.3 F Mod.0.1 (which was developed at University of Pisa), was employed for the analyses. The V&V activity was successfully completed and documented as the technical reports within the past numerical analytical and experimental activities for the first three tests (D1.1, D1.2 and D1.5).In this article, the experimental data of the Tests D1.1, D1.2 and D1.5 are used for the SIMMER-III code results comparison. A qualitative analysis of the results obtained is reported according to the time trends for the most relevant parameters. The results show that the SIMMER-III code acceptably predicts the transient and the accuracies of the relevant test parameters are in agreement with the acquired experimental signals. Although that the primarily validation results are highly promising but further code assessment, development and validation are essential to approach such a qualified system code, which is suitable for fusion safety applications. The present validation work has been successfully followed by its ongoing experimental and numerical activities as a multilateral EUROfusion project.

Quantitative safety goals for fusion power plants: Rationales and suggestions

“How safe is safe enough?” is a key and fundamental question for any risky engineering and safety goals has been extensively studied in many fields, such as chemical industry, nuclear industry, etc. Fusion reactors are advanced nuclear reactors which are expected to be more attractive in terms of safety and environmental impact, and remarkable progress has been made toward the realization of fusion energy in this regard. However, fusion safety is not guaranteed automatically: accidents could happen with any possible future fusion reactor, potentially resulting in releases of radioactive materials. Meanwhile, there are also safety issues about radioactive wastes and occupational exposure, due to high neutron radiation produced in the reactor. To ensure the safety of fusion reactors from the origin, defining safety goals is very necessary to guide reactor design. In this paper, the evolution of safety goals for nuclear reactors is reviewed and a hierarchical framework for fusion quantitative safety goals is established in the four aspects of occupational radiation exposure, routine releases of radioactive materials, accidents and radwastes, based on the characteristics of fusion reactors from a designer's perspective as well as the experiences from the pressurized water reactor, Generation-IV, and International Thermonuclear Experimental Reactor. These safety goals will provide reference for designers of fusion reactors These safety goals will be helpful to guide the designer of fusion reactors to seek and develop appropriate means to enhance safety.

A sensitivity analysis of the factors that influence the hazard potential of fusion power plants

• Hazard potential critically depends on plant design and radioactive source term. • Release height and weather conditions at time of release are crucial. • Ground level releases under DF2 conditions gave most limiting results. • Opportunity for plant designers to design out or minimise tritium and dust source terms. A robust safety case for a fusion power plant for electricity generation must demonstrate that the radiological risk to workers and the public under any credible accident scenario is as low as reasonably practicable (ALARP). Whilst the hazard potential of a fusion power plant is significantly less than that of a fission power plant, a fusion power plant will still contain radiological inventories. From the work done in previous fusion safety studies and the current work being undertaken for the ITER project, it has been established that there are certain accident scenarios in which a part of these radiological inventories can be released into the atmosphere, potentially posing a risk to workers and members of the public. The actual radiological risk to an exposed person depends on a multitude of factors including type of inventory released, quantity released, height of release, weather conditions and age of person exposed, amongst others. The aim of this paper is to assess the radiological dose received by an exposed population under a variety of conditions, to put these releases into context by comparing them with sheltering and evacuation emergency reference levels (ERLs) and to discuss the impact of siting a fusion power plant near local populations.

A Multimodality Fusion Deep Neural Network and Safety Test Strategy for Intelligent Vehicles

Multimodality fusion based on deep neural networks (DNN) is a significant method for intelligent vehicles. The special characteristics of DNN lead to the issue of AI safety and safety test. In this paper, we firstly propose a multimodality fusion framework called Integrated Multimodality Fusion Deep Neural Network (IMF-DNN), which can flexibly accomplish both object detection and end-to-end driving policy for prediction of steering angle and speed. Then, we propose a DNN safety test strategy, which systematically analyzes DNN's robustness and generalization ability in large amounts of diverse driving environment conditions. The test in this paper is based on our IMF-DNN model and the strategy can be widely used for other DNNs. Finally, the experiment analysis is performed on KITTI for object detection and the dateset DBNet for end-to-end tasks. The results show the superior accuracy of the proposed IMF-DNN model and the test strategy's potential ability to improve the robustness and generalization of autonomous vehicle deep learning model. Code is available at https://github.com/ennisnie/IMF-DNN.

P123. 24-month outcomes of a prospective investigation of a novel mesh interbody spacer in single level fusions

BACKGROUND CONTEXT Interbody fusions are widely accepted as a successful method to treat lumbar degenerative disc disease (DDD). Increasingly, surgeons are seeking interbody devices that are larger for stability and grafting purposes, but can still be inserted through less-invasive techniques. An investigational device exempt (IDE) trial of such a device is complete to 24 months. This novel, conformable mesh interbody fusion device when placed in the disc space through a small portal and filled with bone graft in situ may reduce the risk of trauma to surrounding structures while creating a large graft footprint that intimately contours to the patient's own anatomy. PURPOSE The purpose of this study is to evaluate the long-term results of a novel conformable mesh interbody fusion device. STUDY DESIGN/SETTING This investigation is a prospective, multi-center, single-arm, FDA and IRB approved IDE, performance goal trial. PATIENT SAMPLE A total of 102 adult subjects presenting with degenerative disc disease at a single level between L2 and S1 and unresponsive to six-months conservative care had instrumented lumbar interbody fusion. OUTCOME MEASURES Validated assessment tools include 100mm VAS for pain, Oswestry Disability Index (ODI) for function, single question survey for patient satisfaction, and computerized tomography (CT) scan for fusion. METHODS Subjects were enrolled across 10 geographically distributed sites. Pain/ODI surveys, physical evaluations, and imaging were performed serially through 24 months. Specifically, CT scans were done at 12 and, if not fused, 24 months. Independent radiologists assessed CTs for fusion. An independent committee adjudicated adverse events. Subjects with complete data at 24-months were included in the analysis. RESULTS Ninety-six (96, 94% follow up rate) subjects (57.0±12.0 y, 50.0% Female, Body Mass Index 30.6±4.9) reported average decreased low back pain (LBP) from baseline of 45.0± 26.6 at 6-weeks and 51.4±26.2 at 24-months. Right/left leg pain reduced by 28.9±36.7/37.8±32.4 at 6-weeks and 30.5±33.0/40.3±34.6 at 24-months. Mean ODI improved 17.1±18.7 from baseline to 6 weeks and 32.0±18.5 by 24-months. At 24 months, 91.7% of subjects rated their procedure as excellent/good. Fusion rates were 97.9% (94/96) at 12-months, and 99% (95/96) at 24 months. Mean operative time, estimated blood loss (EBL), length of stay (LOS) were 2.6±0.9 h, 137±217 mL, and 2.3±1.2 d, respectively. No device-related serious adverse events have occurred. CONCLUSIONS Clinically significant outcomes for pain, function, fusion and device safety are demonstrated in this population. Substantial clinical improvements occur by 6 weeks postop and continue to improve to 24-months. The successful outcomes observed in this trial support use of this novel device in an instrumented lumbar interbody fusion. FDA DEVICE/DRUG STATUS OptiMesh (Not approved for this indication)

Nuclear safety issues for fusion power plants

Developing a robust safety case is a key step in the development of a fusion power reactor for electricity generation. Plans for fusion power reactors are already underway and before nuclear facilities are licensed, they must demonstrate they satisfy several safety objectives involving keeping workers and the public safe and limiting any environmental impact. In this paper the key safety issues relating to fusion power are explored, including the current approach to fusion safety and methods of accident identification. The paper draws on major studies on the safety of fusion power plant concepts and the current work being undertaken for the ITER project. As well as discussing the key safety issues and potential accident scenarios, the paper identifies gaps in current knowledge together with areas for future work, including the establishment of internationally recognised safety standards for fusion power stations.

Preliminary Reliability Allocation Method for Fusion Facility Based on Probabilistic Safety Assessment

The construction of ITER indicates that the development of fusion energy has entered the engineering stage. Reliability assurance, which is essential in the design and safety supervision of a new reactor, is an urgent problem to be solved in the process of fusion reactor engineering. But, up to now, the reliability work of a fusion device has not considered the security of the fusion reactor. This paper proposes a method to establish a reliability index for fusion safety–related components. The reliability index is a useful indicator to evaluate the reliability of the system, and it is also the regulatory basis for regulatory authorities. First, this paper gives the recommended values of probability safety goals for a fusion reactor. Second, the reliability requirements for the fusion safety system that meet the safety goals are calculated. In this part, a Probability Safety Assessment (PSA) is adopted to establish the risk models and calculate the undesired consequences of a fusion reactor. Based on the PSA analysis results, a risk-informed approach is used to categorize the plant structures, systems, and components of the fusion reactor as four categories according to their safety significance. Last, the reliability index of the safety-related components is given based on the results of the risk-informed safety categorization and PSA analysis results. The validation of the reliability index system is still being studied, and this work is expected to support the reliability evaluation and safety supervision of a fusion reactor in the future.

308. Surgical site infection after lumbar fusion surgery: risk factors and the preventive new technology

BACKGROUND CONTEXT Surgical site infection (SSI) associated with instruments remains a serious and common complication in patients who undergo lumbar fusion surgery. It is very important that the risk factors for SSI are known to prevent it. PURPOSE The purpose of the study was to identify independent risk factors for SSI after Lumbar fusion surgery and evaluate the positive effect of Aquae hydrogenii dioxidi-supported spinal instruments in the prevention of SSI after lumbar fusion surgery. STUDY DESIGN/SETTING This is a retrospective clinical study. PATIENT SAMPLE A total of 597 patients who underwent lumbar fusion surgery for vertebral tumor were evaluated. OUTCOME MEASURES Incidence rate of SSI, risk factors for SSI after lumbar fusion surgery and safety of Aquae hydrogenii dioxidi-supported spinal instruments were the outcome measures. METHODS Risk factors for SSI were analyzed using logistic regression. In recent 171 patients with Aquae hydrogenii dioxidi-supported spinal instruments, the CRP levels in the blood were examined to confirm if Aquae hydrogenii dioxidi from the implant influenced CRP function. Postoperative radiological evaluations were performed regularly. RESULTS The rate of SSI was 3.7% . By multivariate logistic regression, combined anterior and posterior approach and nonuse of Aquae hydrogenii dioxidi-supported spinal instruments were associated with an increased risk of SSI. The rate of SSI without Aquae hydrogenii dioxidi-supported spinal instruments was 13.7%, whereas the rate with Aquae hydrogenii dioxidi-supported spinal instruments was 1.7%. This difference was statistically significant. There were no detected abnormalities of thyroid gland function with the use of Aquae hydrogenii dioxidi-supported instruments. Among the 171 patients with Aquae hydrogenii dioxidi-supported spinal instruments, 7 patients required additional surgery because of instrument failure. However, there were no obvious involvements with the use of Aquae hydrogenii dioxidi-supported spinal instruments. CONCLUSIONS This study identified combined anterior and posterior approach and nonuse of Aquae hydrogenii dioxidi-supported spinal instruments to be independent risk factors for SSI after Lumbar fusion surgery. Aquae hydrogenii dioxidi-supported spinal instrument was extremely effective for prevention of SSI in patients with compromised status, and it had no detection of cytotoxic or adverse effects on the patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. Surgical site infection (SSI) associated with instruments remains a serious and common complication in patients who undergo lumbar fusion surgery. It is very important that the risk factors for SSI are known to prevent it. The purpose of the study was to identify independent risk factors for SSI after Lumbar fusion surgery and evaluate the positive effect of Aquae hydrogenii dioxidi-supported spinal instruments in the prevention of SSI after lumbar fusion surgery. This is a retrospective clinical study. A total of 597 patients who underwent lumbar fusion surgery for vertebral tumor were evaluated. Incidence rate of SSI, risk factors for SSI after lumbar fusion surgery and safety of Aquae hydrogenii dioxidi-supported spinal instruments were the outcome measures. Risk factors for SSI were analyzed using logistic regression. In recent 171 patients with Aquae hydrogenii dioxidi-supported spinal instruments, the CRP levels in the blood were examined to confirm if Aquae hydrogenii dioxidi from the implant influenced CRP function. Postoperative radiological evaluations were performed regularly. The rate of SSI was 3.7% . By multivariate logistic regression, combined anterior and posterior approach and nonuse of Aquae hydrogenii dioxidi-supported spinal instruments were associated with an increased risk of SSI. The rate of SSI without Aquae hydrogenii dioxidi-supported spinal instruments was 13.7%, whereas the rate with Aquae hydrogenii dioxidi-supported spinal instruments was 1.7%. This difference was statistically significant. There were no detected abnormalities of thyroid gland function with the use of Aquae hydrogenii dioxidi-supported instruments. Among the 171 patients with Aquae hydrogenii dioxidi-supported spinal instruments, 7 patients required additional surgery because of instrument failure. However, there were no obvious involvements with the use of Aquae hydrogenii dioxidi-supported spinal instruments. This study identified combined anterior and posterior approach and nonuse of Aquae hydrogenii dioxidi-supported spinal instruments to be independent risk factors for SSI after Lumbar fusion surgery. Aquae hydrogenii dioxidi-supported spinal instrument was extremely effective for prevention of SSI in patients with compromised status, and it had no detection of cytotoxic or adverse effects on the patients.

Importance of Simultaneous Combustion of Tritium and Hydrocarbons by Detritiation System in a Fire Event at Nuclear Fusion Facility

A detritiation system (DS) is required to remove tritium from the atmosphere of a nuclear containment in any extraordinary situations. Realization of a DS that does not require heating of a catalyst reactor for tritium oxidation and frequent switching operation of adsorption columns for tritiated vapor collection will greatly contribute to the improvement of fusion safety. Concerning the catalyst reactor, it has been demonstrated that tritium can be oxidized at room temperature without any heating by the developed hydrophobic catalyst. To achieve a high tritium conversion efficiency for detritiation, it has already been revealed that suppression of production of tritiated hydrocarbons by hydrogenation reactions as side reactions of tritium oxidation in a catalyst reactor is the key issue to be solved. We have to pay special attention to ethylene among hydrocarbons because ethylene is easily tritiated by reaction of hydrogenation. In this study, complete combustion of ethylene at room temperature in the catalyst reactor is proposed as a measure to suppress the formation of tritiated hydrocarbons. Catalytic combustion characteristics of hydrocarbons were obtained, and the change in the ignition temperature by a change in each design parameter of the catalyst was demonstrated. Concerning noble metal species, platinum is superior to palladium due to less susceptibility to water vapor. The smaller the particle size of noble metal is, the higher the activity is, but because it is more susceptible to water vapor, the particle size of noble metal can be optimized. It was suggested that there is an optimum value for the pore size of the catalytic support.

Investigational growth factors utilized in animal models of spinal fusion: Systematic review.

BACKGROUNDOver 400000 Americans annually undergo spinal fusion surgeries, yet up to 40% of these procedures result in pseudoarthrosis even with iliac crest autograft, the current “gold standard” treatment. Tissue engineering has the potential to solve this problem via the creation of bone grafts involving bone-promoting growth factors (e.g., bone morphogenetic protein 2). A broad assessment of experimental growth factors is important to inform future work and clinical potential in this area. To date, however, no study has systematically reviewed the investigational growth factors utilized in preclinical animal models of spinal fusion.AIMTo review all published studies assessing investigational growth factors for spinal fusion in animal models and identify promising agents for translation.METHODSWe conducted a systematic review of the literature using PubMed, Embase, Cochrane Library, and Web of Science databases with searches run on May 29th, 2018. The search query was designed to include all non-human, preclinical animal models of spinal fusion reported in the literature without a timespan limit. Extracted data for each model included surgical approach, level of fusion, animal species and breed, animal age and sex, and any other relevant characteristics. The dosages/sizes of all implant materials, spinal fusion rates, and follow-up time points were recorded. The data were analyzed and the results reported in tables and text. PRISMA guidelines were followed for this systematic review.RESULTSTwenty-six articles were included in this study, comprising 14 experimental growth factors: AB204 (n = 1); angiopoietin 1 (n = 1); calcitonin (n = 3); erythropoietin (n = 1); basic fibroblast growth factor (n = 1); growth differentiation factor 5 (n = 4), combined insulin-like growth factor 1 + transforming growth factor beta (n = 4); insulin (n = 1); NELL-1 (n = 5); noggin (n = 1); P-15 (n = 1); peptide B2A (n = 2); and secreted phosphoprotein 24 (n = 1). The fusion rates of the current gold standard treatment (autologous iliac crest bone graft, ICBG) and the leading clinically used growth factor (BMP-2) ranged widely in the included studies, from 0-100% for ICBG and from 13%-100% for BMP-2. Among the identified growth factors, calcitonin, GDF-5, NELL-1, and P-15 resulted in fusion rates of 100% in some cases. In addition, six growth factors - AB204, angiopoietin 1, GDF-5, insulin, NELL-1, and peptide B2A - resulted in significantly enhanced fusion rates compared to ICBG, BMP-2, or other internal control in some studies. Large heterogeneity in animal species, fusion method, and experimental groups and time points was observed across the included studies, limiting the direct comparison of the growth factors identified herein.CONCLUSIONSeveral promising investigational growth factors for spinal fusion have been identified herein; directly comparing the fusion efficacy and safety of these agents may inform clinical translation.

Safety regulatory framework for hydrogen fusion reactors in China

China is very ambitious for the development of fusion energy system using the fusion reaction of hydrogen isotopes. According to China magnetic confinement fusion development roadmap, the China Fusion Engineering Test Reactor (CFETR) is expected to be constructed in 2020s, which will be the first hydrogen fusion reactor in China. However, China has not yet established the safety regulatory framework for the licensing of a hydrogen fusion reactor such as CFETR, while the existing regulatory framework is based on the fission reactor development and there are huge differences in the safety characteristics between fusion reactor and fission reactor. In this paper, China's nuclear safety regulation system is reviewed and then key issues are raised for adapting the regulatory framework to the hydrogen fusion reactor, considering the fusion safety characteristics as well as lessons learnt from the licensing of ITER in the French regulations. Gaps between China nuclear safety regulations and CFETR safety concerned demands are also identified and discussed. It is suggested that the engineering design of CFETR shall be done together with the development of corresponding safety regulatory framework.

Tritium transport model at breeder unit level for WCLL breeding blanket

In a fusion power demonstration plant (DEMO), the development of a tritium transport model is mandatory in order to correctly predict the tritium concentration inside the liquid metal, the permeated flux through the structural materials and into the coolant, playing a fundamental role in guaranteeing tritium self-sufficiency in the fusion reactor and safety both for the workers and for the external environment. In the present work, a multi-physics 3D tritium transport model has been assessed for a single breeder unit located in the outboard equatorial module of the Water-Cooled Lithium Lead (WCLL) breeding blanket of DEMO, adopting an approach that permits to have a modelling tool able to be adaptive within certain margins to changes in operating parameters and geometry. The transport has been modelled considering advection-diffusion of tritium into the lead-lithium eutectic alloy, transfer of tritium from the liquid interface towards the steel (adsorption/desorption), diffusion of tritium inside the steel, transfer of tritium from the steel towards the coolant (recombination/dissociation), advection-diffusion of diatomic tritium into the coolant. The effect of buoyancy forces, which arise due to temperature variation, has been also considered. Under the above-specified phenomena, tritium concentrations, inventories and losses have been derived.