Partial flow blockage analysis of the hottest fuel assembly in SNCLFR-100 reactor core

In this paper, we perform an unprotected partial flow blockage analysis of the hottest fuel assembly in the core of the SNCLFR-100 reactor, a 100 MW_(th) modular natural circulation lead-cooled fast reactor, developed by University of Science and Technology of China. The flow blockage shall cause a degradation of the heat transfer between the fuel assembly and the coolant potentially,which can eventually result in the clad fusion. An analysis of core blockage accidents in a single assembly is of great significance for LFR. Such scenarios are investigated by using the best estimation code RELAP5. Reactivity feedback and axial power profile are considered. The crosssectional fraction of blockage, axial position of blockage,and blockage-developing time are discussed. The cladding material failure shall be the biggest challenge and shall be a considerable threat for integrity of the fuel assembly if the cross-sectional fraction of blockage is over 94%. The blockage-developing time only affects the accident progress. The consequence will be more serious if the axial position of a sudden blockage is closer to the core outlet.The method of analysis procedure can also be applied to analyze similar transient behaviors of other fuel-type reactors.

Advances in the microbial mineralization of seafloor hydrothermal systems

Research on the biomineralization in modern seafloor hydrothermal systems is conducive to unveiling the mysteries of the early Earth’s history, life evolution, subsurface biosphere and microbes in outer space. The hydrothermal biomineralization has become a focus of geo-biological research in the last decade, since the introduction of the microelectronic technology and molecular biology technology. Microorganisms play a critical role in the formations of oxide/hydroxides (e.g. Fe, Mn, S and Si oxide/hydroxides) and silicates on the seafloor hydrothermal systems globally. Furthermore, the biomineralization of modern chemolithoautotrophic microorganisms is regarded as a nexus between the geosphere and the biosphere, and as an essential complement of bioscience and geology. In this paper, we summarize the research progress of hydrothermal biomineralization, including the biogenic minerals, the microbial biodiversity, and also the interactions between minerals and microorganisms. In the foreseeable future, the research on hydrothermal biomineralization will inspire the development of geosciences and biosciences and thus enrich our knowledge of the Earth’s history, life evolution and even astrobiology.

Thermal recovery method of submarine gas hydrate based on a thermoelectric generator

1.Objective Natural gas hydrates are considered as a potential alternative fuel resource to petroleum and gas (Chong ZR et al.,2016),which can be exploited by means of depressurization,thermal method,inhibitor injection,etc.For the thermal method,gas hydrates are decomposed into water and methane when the reservoir is heated to above the equilibrium temperature of gas hydrate (Li X et al.,2016). However,the thermal recovery method needs a great deal of heat,and thus the feasibility of economic exploitation is reduced.

Preventive Effect of Perioperative Management Using Oral Clopidogrel on Postoperative Rebleeding in Patients with Spontaneous Intracerebral Hemorrhage

Background: With the aging society in China and the increasing incidence of cardiovascular and cerebrovascular diseases,spontaneous cerebral hemorrhage with the use of oral clopidogrel has become common in patients. Owing to its inhibition of platelet aggregation,oral clopidogrel results in a high incidence of postoperative intracranial rebleeding,and the prognosis is poor. The purpose of this study is to determine the effect of perioperative management of spontaneous intracerebral hemorrhage (SICH) using oral clopidogrel on postoperative rebleeding. Methods: From January 2010 to June 2018,64 patients with SICH who took clopidogrel orally and finally received surgical treatment were selected from Huzhou First People’s Hospital and the Second Affiliated Hospital of Wenzhou Medical University. The influencing factors of postoperative rebleeding were analyzed via a case-control study. Results: All patients with SICH were divided into two groups according to the standard time of drug withdrawal before surgery: drug withdrawal at < 3 days and ≥ 3 days. The incidence of postoperative rebleeding after drug withdrawal at ≥ 3 days was significantly lower than that after drug withdrawal at < 3 days. Thereafter,all patients were divided into two groups according to the adenosine diphosphate (ADP) inhibition rate detected using a thromboelastography monitor: ADP inhibition rate of < 60% and ≥ 60%. The incidence of postoperative rebleeding in the ADP inhibition rate of < 60% group was significantly lower than that in the ADP inhibition rate of ≥ 60% group. In addition,drug withdrawal at ≥ 3 days and ADP inhibition rate of < 60% had a synergistic effect on the prevention of postoperative rebleeding. Conclusions: Patients with drug withdrawal at ≥ 3 days can undergo active early surgery. The ADP inhibition rate of ≥ 60% can be used as the predictive index of high-risk postoperative rebleeding in patients with SICH taking oral clopidogrel. By reducing the ADP inhibition rate to < 60%,the incidence of postoperative rebleeding can also be reduced.