Background:To evaluate sex‐related differences in the risk factors associated with nonhealing or recurrence of hyper-thyroidism(NHRH)in patients with Graves'disease(GD)treated with radioactive iodine.Methods:In t...Background:To evaluate sex‐related differences in the risk factors associated with nonhealing or recurrence of hyper-thyroidism(NHRH)in patients with Graves'disease(GD)treated with radioactive iodine.Methods:In total,285 patients were enrolled.Data on radioactive iodine(RAI)dosage,ultrasound indexes of the thyroid,and other clinical factors were collected.Patients were divided into NHRH and non‐NHRH(hypothyroidism or euthyroidism)groups based on treatment outcomes.Univariate and multivariate weighted logistic regression analyses were used to identify factors associated with NHRH.Sex‐specific analyses of these risk factors were also conducted.Results:There were no significant differences between the two groups in terms of sex,thyroid shear wave elastography velocity values,or pretreatment serum free thyroxine(FT4)levels.Thyroid volume and age were independently associated with NHRH,with the odds of NHRH gradually decreasing as age increased.In subgroup analyses,both age and thyroid volume were independent risk factors for NHRH in female patients(p<0.05),while in male patients,only FT4 was independently associated with NHRH(p<0.05).Conclusions:In patients of different sexes,the influence of thyroid volume,age,and FT4 on treatment outcomes exhibits distinct patterns.展开更多
Malignant tumours always threaten human health.For tumour diagnosis,positron emission tomography(PET)is the most sensitive and advanced imaging technique by radiotracers,such as radioactive^(18)F,^(11)C,^(64)Cu,^(68)G...Malignant tumours always threaten human health.For tumour diagnosis,positron emission tomography(PET)is the most sensitive and advanced imaging technique by radiotracers,such as radioactive^(18)F,^(11)C,^(64)Cu,^(68)Ga,and^(89)Zr.Among the radiotracers,the radioactive^(18)F-labelled chemical agent as PET probes plays a predominant role in monitoring,detecting,treating,and predicting tumours due to its perfect half-life.In this paper,the^(18)F-labelled chemical materials as PET probes are systematically summarized.First,we introduce various radionuclides of PET and elaborate on the mechanism of PET imaging.It highlights the^(18)F-labelled chemical agents used as PET probes,including[^(18)F]-2-deoxy-2-[^(18)F]fluoro-D-glucose([^(18)F]-FDG),^(18)F-labelled amino acids,^(18)F-labelled nucleic acids,^(18)F-labelled receptors,^(18)F-labelled reporter genes,and^(18)F-labelled hypoxia agents.In addition,some PET probes with metal as a supplementary element are introduced briefly.Meanwhile,the^(18)F-labelled nanoparticles for the PET probe and the multi-modality imaging probe are summarized in detail.The approach and strategies for the fabrication of^(18)F-labelled PET probes are also described briefly.The future development of the PET probe is also prospected.The development and application of^(18)F-labelled PET probes will expand our knowledge and shed light on the diagnosis and theranostics of tumours.展开更多
This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of...This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of thermo-poro-elastoplasticity theory is first summarized.The emphasis is put on the effect of pore fluid pressure on plastic deformation.A micromechanics-based elastoplastic model is then presented for a class of clayey rocks considered as host rock.Based on linear and nonlinear homogenization techniques,the proposed model is able to systematically account for the influences of porosity and mineral composition on macroscopic elastic properties and plastic yield strength.The initial anisotropy and time-dependent deformation are also taken into account.The induced cracking process is described by using a non-local damage model.A specific hybrid formulation is proposed,able to conveniently capture tensile,shear and mixed cracks.In particular,the influences of pore pressure and confining stress on the shear cracking mechanism are taken into account.The proposed model is applied to investigating thermo-hydromechanical responses and induced damage evolution in laboratory tests at the sample scale.In the last part,an in situ heating experiment is analyzed by using the proposed model.Numerical results are compared with experimental data and field measurements in terms of temperature variation,pore fluid pressure change and induced damaged zone.展开更多
Radioactive microspheres have demonstrated excellent therapeutic effects and good tolerance in the treatment of unresectable primary and secondary liver malignancies.This is attributed to precise embolization and pote...Radioactive microspheres have demonstrated excellent therapeutic effects and good tolerance in the treatment of unresectable primary and secondary liver malignancies.This is attributed to precise embolization and potent anti-tumor effect.However,certain limitations such as unstable loading,perfusion stasis,heterogeneous distribution,ectopic distribution,and insufficient dosage,restrict their clinical application.Herein,a novel personalized Y-90 carbon microsphere with high uniformity,high specific activity and high availability(^(90)Y-HUACM)is presented.It is synthesized through planar molecular complex adsorption and chemical deposition solidification.^(90)Y-HUACM exhibited controllable size,excellent biocompatibility,outstanding in vitro and in vivo stability.The radiolabeling efficiency of Y-90 exceeded 99%and the leaching rate of Y-90 is far below 0.1%.Furthermore,the excellent anti-tumor effect,nuclide loading stability,anti-reflux characteristics,precise embolization,and biosafety of^(90)Y-HUACM were validated in a rabbit VX2liver tumor model.In summary,this new,high-performance,and customizable radioactive microsphere provides a superior choice for selective internal radiation treatment of advanced liver cancer is expected to be rapidly applied in clinical practice.展开更多
BACKGROUND Radiation enteritis is a common complication of radiation therapy in which the surrounding normal intestinal tissue is damaged by ionising radiation,and there is no standard pharmacological prophylaxis or t...BACKGROUND Radiation enteritis is a common complication of radiation therapy in which the surrounding normal intestinal tissue is damaged by ionising radiation,and there is no standard pharmacological prophylaxis or treatment regimen available.Mesenchymal stem cell transplantation can be used for radiation protection and the treatment of acute radiation injury,but its therapeutic mechanism of action remains unclear.AIM To investigate the protective effects of autologous bone marrow-derived mesenchymal stem cell(ABMSC)transplantation on radiation-induced intestinal injury.METHODS A model of acute radioactive enteritis was established in dogs by applying abdominal intensity-modulated radiation at a single X-ray dose of 12 Gy.ABMSCs were transplanted into the mesenteric artery with the technology of femoral artery puncture and DSA imaging two days after radiation.Visual and histopathological changes of the experimental dogs were observed.Different kinds of cytokines from intestinal samples were tested using Quantibody Canine Cytokine Array method.Enzyme-linked immunosorbent assay(ELISA)was also used to evaluate the cytokines changes in serum.RESULTS The ABMSCs group showed significant improvements in survival status compared with the blank and saline treatment groups.Histological observations revealed that the former had lower histological scores than the later after treatment(P<0.05).Compared to the control groups,interleukin(IL)-10 and monocyte chemotactic protein(MCP)-1 from intestinal samples showed a remarkable increase and ELISA of serum samples proved higher secretion of the two target cytokines in the ABMSCs group(P<0.05).CONCLUSION Our data suggest that transplantation of ABMSCs promotes intestinal recovery after acute radioactive injury in Beagle dogs.The cytokines of IL-10 and MCP-1 might play an important role in this process.展开更多
To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.T...To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.The methods currently used for measuring dose rates are inadequate for obtaining the dose rates of key radionuclides and have large angular response errors when monitoring surface sources.To address this practical problem,this study proposes three methods for measuring the dose rate:the weighted peak total ratio,mean value regression,and numerical integration methods.These methods are based on energy-spectrum measurement data,and they were theoretically derived and numerically evaluated.Finally,a 1-m-long hexagonal radioactive surface source was integrated into a larger surface source.In situ measurement experiments were conducted on a large radioactive surface source using a dose-rate meter and a portable HPGespectrometer to analyze the errors of the three aforementioned methods and verify their validity.展开更多
Alkaline igneous rocks represent one of the most economically important resources of radioactive minerals and rare metals.New field observations and petrographic studies are integrated with whole-rock geochemical anal...Alkaline igneous rocks represent one of the most economically important resources of radioactive minerals and rare metals.New field observations and petrographic studies are integrated with whole-rock geochemical analyses and Gamma ray spectroscopy data of alkaline rocks associated with the Amreit complex.The fieldwork was achieved by the collection of more than forty samples from alkaline granites and alkaline syenites.The youngest rocks cropping out in the study area are the cogenetic alkaline rocks,ranging from alkaline granite to alkaline syenite.These alkaline rocks are composed essentially of K-feldspar,alkali amphiboles(arfvedsonite),and sodic pyroxene,with accessories such as zircon,apatite,and ilmenite.Mineral characterization of the highly radioactive zones in both alkaline granite and alkaline syenite displays enrichment in monazite,thorite,zircon,ferro-columbite,xenotime,and allanite minerals.Geochemical analyses indicate that the Amreit rocks are alkaline with peralkaline affinity and have high concentrations of total alkalis(K_(2)O+Na_(2)O),large ion lithophile elements(LILEs;Ba and Rb),high field strength elements(HFSEs;Y,Zr and Nb),rare earth elements(REEs)and significantly depleted in K,Sr,P,Ti,and Eu,typically of post-collision A-type granites.Typically,the Amreit alkaline igneous rocks are classified as within plate granites and display A2 subtype characteristics.The fractionation of K-feldspars played a distinctive role during the magmatic evolution of these alkaline rocks.The geochemical characteristics indicate that the studied alkaline igneous rocks which were originated by fractional crystallization of alkaline magmas were responsible for the enrichment of the REE and rare metals in the residual melt.The high radioactivity is essentially related to accessory minerals,such as zircon,allanite,and monazite.The alkaline granite is the most U-and Thrich rock,where radioactivity level reaches up to 14.7 ppm(181.55 Bq/kg)e U,40.6 ppm(164.84 Bq/kg)e Th,whereas in alkaline syenite radioactivity level is 8.5 ppm(104.96 Bq/kg)e U,30.2 ppm(122.61 Bq/kg)e Th.These observations suppose that these alkaline rocks may be important targets for REEs and radioactive mineral exploration.展开更多
Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to...Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository.Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater,and was used to hydrate the blocks during the swelling pressure and swelling strain measurements,as Beishan is the most promising site for China's repository.Healing of the surface cracks was recorded by photography,and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks.The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater,but not affected by the drying cracks.The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks.The maximum swelling pressure measured in strong(i.e.high ion strength)Beishan groundwater was 44%of the pressure measured in deionized(DI)water,and the maximum swelling strain was reduced to 23%of the strain measured in DI water.Nevertheless,the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks,as demonstrated by the pictures of surface cracks and CT images.The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable(3.7×higher)to the hydraulic conductivity of the fresh block,indicating the self-healing of drying cracks after hydration and swelling in groundwater.A simplified method of protecting the block with plastic wraps before installation is recommended,since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.展开更多
This paper addresses numerical analysis of thermo-hydromechanical processes in the context of deep geological disposal of radioactive waste.The emphasis is put on modeling of damaged zones induced by excavation,pore p...This paper addresses numerical analysis of thermo-hydromechanical processes in the context of deep geological disposal of radioactive waste.The emphasis is put on modeling of damaged zones induced by excavation,pore pressure and temperature changes.The theoretical background of thermo-poroelasticity for saturated porous media is first recalled.The framework for modeling initiation and evolution of induced cracks is then presented by using a variational approach of phase-field method.A specific model with two crack phase fields and considering thermo-hydromechanical interaction is proposed.A particular attention is paid on the description of shear cracks.The proposed model is implemented in the standard finite element method.An example of application is finally presented on the analysis of thermo-hydromechanical responses and cracked zones evolution around a typical disposal repository in the context of French concept for high level waste disposal.展开更多
The deep geological repository for radioactive waste in Switzerland will be embedded in an approximately 100 m thick layer of Opalinus Clay.The emplacement drifts for high-level waste(approximately 3.5 m diameter)are ...The deep geological repository for radioactive waste in Switzerland will be embedded in an approximately 100 m thick layer of Opalinus Clay.The emplacement drifts for high-level waste(approximately 3.5 m diameter)are planned to be excavated with a shielded tunnel boring machine(TBM)and supported by a segmental lining.At the repository depth of 900 m in the designated siting region Nordlich Lagern,squeezing conditions may be encountered due to the rock strength and the high hydrostatic pressure(90 bar).This paper presents a detailed assessment of the shield jamming and lining overstressing hazards,considering a stiff lining(resistance principle)and a deformable lining(yielding principle),and proposes conceptual design solutions.The assessment is based on three-dimensional transient hydromechanical simulations,which additionally consider the effects of ground anisotropy and the desaturation that may occur under negative pore pressures generated during the drift excavation.By addressing these design issues,the paper takes the opportunity to analyse some more fundamental aspects related to the influences of anisotropy and desaturation on the development of rock convergences and pressures over time,and their markedly different effects on the two lining systems.The results demonstrate that,regardless of these effects,shield jamming can be avoided with a moderate TBM overcut,however overstressing of a stiff lining may be critical depending on whether the ground desaturates.This uncertainty is eliminated using a deformable system with reasonable dimensions of yielding elements,which can also accommodate thermal strains generated due to the high temperature of the disposal canisters.展开更多
In the process of extracting ion-absorbed rare earth ore(IREO),the production of radioactive waste is a major environmental concern.To address this issue,MoS_(2) was used to modify ion-absorbed rare earth tailings(RET...In the process of extracting ion-absorbed rare earth ore(IREO),the production of radioactive waste is a major environmental concern.To address this issue,MoS_(2) was used to modify ion-absorbed rare earth tailings(RET) to synthesize a novel MoS_(2)@RET composite material for the effective handling of radioactive waste generated in IREO separation industry.The composite material was thoroughly characterized using various analytical techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetry(TG),Fourier-transform infrared(FTIR),scanning electron microscopy(SEM),Brunaue r-Emmett-Teller(BET) and energy dispersive spectroscopy(EDS).By optimizing the operating parameters,the optimal experimental conditions were determined to be pH=3,contact time=60 min,liquid-solid ratio=6 g/L,and initial concentration=150 mg/L.The adsorption data fitted well with the pseudo second-order rate model.The thermodynamic parameters concerning the adsorption of Th(Ⅳ) were analyzed and computed.Langmuir isotherm model is a more fitting choice for the adsorption process compared to the Freundlich isotherm model.MoS_(2)@RET was used in the acid leachate of IREO waste residue,achieving the separation of Th and rare earth successfully.The mechanism of Th(Ⅳ) adsorption by MoS_(2)@RET was investigated,revealing that the adsorption process involves electrostatic interactions,chemical bonding,and redox reactions.The above research results indicate that MoS_(2)@RET composite materials have application potential in the sustainable treatment of IREO radioactive waste.展开更多
Based on the dinuclear system model,the synthesis of the predicted double-magic nuclei^(298)Fl and 304120 was investigated via neutron-rich radioactive beam-induced fusion reactions.The reaction^(58)Ca+^(244)Pu is pre...Based on the dinuclear system model,the synthesis of the predicted double-magic nuclei^(298)Fl and 304120 was investigated via neutron-rich radioactive beam-induced fusion reactions.The reaction^(58)Ca+^(244)Pu is predicted to be favorable for producing^(298)Fl with a maximal ER cross section of 0.301 pb.Investigations of the entrance channel effect reveal that the^(244)Pu target is more promising for synthesizing^(298)Fl than the neutron-rich targets^(248)Cm and^(249)Bk,because of the influence of the Coulomb barrier.For the synthesis of 304120,the maximal ER cross section of 0.046 fb emerges in the reaction^(58)V+^(249)Bk,indicating the need for further advancements in both experimental facilities and reaction mechanisms.展开更多
BACKGROUND Radioactive iodine-125(125I)microparticle therapy is a new type of internal radiation therapy that has shown unique advantages in the treatment of malignant tumors,especially hepatocellular carcinoma.Patien...BACKGROUND Radioactive iodine-125(125I)microparticle therapy is a new type of internal radiation therapy that has shown unique advantages in the treatment of malignant tumors,especially hepatocellular carcinoma.Patients with hepatocellular carcinoma frequently experience portal vein embolism,which exacerbates the difficulty and complexity of treatment.125I particles,used in local radiotherapy,can directly act on tumor tissue and reduce damage to surrounding healthy tissue.Through retrospective analysis,this study discussed the efficacy and safety of radioactive 125I particles in portal vein embolization patients with hepatocellular carcinoma in order to provide more powerful evidence supporting clinical treatment.AIM To investigate the effect of transcatheter arterial chemoembolization combined with portal vein 125I particle implantation in the treatment of primary liver cancer patients with portal vein tumor thrombus and its influence on liver function.METHODS The clinical data of 96 patients with primary liver cancer combined with portal vein tumor thrombus admitted to our hospital between January 2020 and December 2023 were retrospectively analyzed.Fifty-two patients received treatment with transcatheter arterial chemoembolization and implantation of 125I particles in the portal vein(combination group),while 44 patients received treatment with transcatheter arterial chemoembolization alone(control group).The therapeutic effects on tumor lesions,primary liver cancer,and portal vein tumor embolisms were compared between the two groups.Changes in relevant laboratory indexes before and after treatment were evaluated.The t test was used to compare the measurement data between the two groups,and the χ^(2) test was used to compare the counting data between groups.RESULTS The tumor lesion response rate in the combination group(59.62%vs 38.64%)and the response rate of patients with primary liver cancer complicated with portal vein tumor thrombus(80.77%vs 59.09%)were significantly greater than those in the control group(χ^(2)=4.196,5.421;P=0.041,0.020).At 8 wk after surgery,the serum alpha-fetoprotein,portal vein main diameter,and platelet of the combined group were significantly lower than those of the control group,and the serum alanine aminotransferase,aspartate aminotransferase,and total bilirubin were significantly greater than those of the control group(t=3.891,3.291,2.330,3.729,3.582,4.126;P<0.05).The serum aspartate aminotransferase,alanine aminotransferase,and total bilirubin levels of the two groups were significantly greater than those of the same group 8 wk after surgery(P<0.05),and the peripheral blood platelet,alphafetoprotein,and main portal vein diameter were significantly less than those of the same group before surgery(P<0.05).CONCLUSION In patients with primary liver cancer and a thrombus in the portal vein,transcatheter arterial chemoembolization plus portal vein 125I implantation is more effective than transcatheter arterial chemoembolization alone.However,during treatment it is crucial to pay attention to liver function injury caused by transcatheter arterial chemoembolization.展开更多
Clays and argillites are considered in some countries as possible host rocks for nuclear waste disposal at great depth.The use of compacted swelling clays as engineered barriers is also considered within the framework...Clays and argillites are considered in some countries as possible host rocks for nuclear waste disposal at great depth.The use of compacted swelling clays as engineered barriers is also considered within the framework of the multi-barrier concept.In relation to these concepts,various research programs have been conducted to assess the thermo-hydro-mechanical properties of radioactive waste disposal at great depth.After introducing the concepts of waste isolation developed in Belgium,France and Switzerland,the paper describes the retention and transfer properties of engineered barriers made up of compacted swelling clays in relation to microstructure features.Some features of the thermo-mechanical behaviors of three possible geological barriers,namely Boom clay（Belgium）,Callovo-Oxfordian clay（France） and Opalinus clay（Switzerland）,are then described,including the retention and transfer properties,volume change behavior,shear strength and thermal aspects.展开更多
The policy and principles on management of radioactive wastes are stipulated.Cement solidification and bituminization unit has come into trial run. Solid radioactive waste is stored in tentative storage vault built...The policy and principles on management of radioactive wastes are stipulated.Cement solidification and bituminization unit has come into trial run. Solid radioactive waste is stored in tentative storage vault built in each of nuclear faCilities. Seventeen storages associated with applications of nuclear technology and radioisotopes have been built for provinces. Disposal of low and intermediate level radioactive wastes pursues the policy of 'regional disposal'. Four repositories have been planned to be built in northwest, southwest, south and east China respectively. A program for treatment and disposal of high level radioactive waste has been made.展开更多
With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is inte...With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories（URLs） play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China＇s URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area,located in Gansu Province of northwestern China, has been selected as the final site for China＇s first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations,including borehole drilling,geological mapping, geophysical surveying,hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological,hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel（BET）, which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone（EDZ）, and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction.According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.展开更多
For geological disposal of high-level radioactive waste （HLW）, the Chinese policy is that the spent nuclear fuel （SNF） should be reprocessed first, followed by vitrification and final disposal. The preliminary rep...For geological disposal of high-level radioactive waste （HLW）, the Chinese policy is that the spent nuclear fuel （SNF） should be reprocessed first, followed by vitrification and final disposal. The preliminary repository concept is a shaft-tunnel model, located in saturated zones in granite, while the final waste form for disposal is vitrified high-level radioactive waste. In 2006, the government published a long-term research and development （R＆D） plan for geological disposal of high-level radioactive waste. The program consists of three steps： （1） laboratory studies and site selection for a HLW repository （2006-2020）; （2） underground in-situ tests （2021-2040）; and （3） repository construction （2041-2050） followed by operation. With the support of China Atomic Energy Authority, comprehensive studies are underway and some progresses are made. The site characterization, including deep borehole drilling, has been performed at the most potential Beishan site in Gansu Province, Northwestern China. The data from geological and hydrogeological investigations, in-situ stress and permeability measurements of rock mass are presented in this paper. Engineered barrier studies are concentrated on the Gaomiaozi bentonite. A mock-up facility, which is used to study the thermo-hydro-mechano-chemical （THMC） properties of the bentonite, is under construction. Several projects on mechanical properties of Beishan granite are also underway. The key scientific challenges faced with HLW disposal are also discussed.展开更多
Objective:To test the curative effect of human umbilical cord-derived mesenchymal stem cells on rat acute radioactive enteritis and thus in provide clinical therapeutic basis for radiation sickness.Methods:Human umbil...Objective:To test the curative effect of human umbilical cord-derived mesenchymal stem cells on rat acute radioactive enteritis and thus in provide clinical therapeutic basis for radiation sickness.Methods:Human umbilical cord-derived mesenchymal stem cells were cultivated in vitro and the model of acute radioactive enteritis of rats was established.Then,the umbilical cord mesenchymal stem cells were injected into the rats via tail vein.Visual and histopathiological changes of the experimental rats were observed.Results:After the injection,the rats in the prevention group and treatment group had remarkably better survival status than those in the control group.The histological observations revealed that the former also had better intestinal mucosa structure,more regenerative cells and stronger proliferation activity than the latter.Conclusions:Human umbilical cord-derived mesenchymal stem cells have a definite therapeutic effect on acute radioactive enteritis in rats.展开更多
Radioactive noble-gas isotopes, SSKr （half-life tl/2=10.8 y）, 39Ar （tl/2=269 y）, and SlKr （t1/2-229,000 y）, are ideal tracers and can be detected by atom trap trace analysis （ATTA）, a laser-based technique, fr...Radioactive noble-gas isotopes, SSKr （half-life tl/2=10.8 y）, 39Ar （tl/2=269 y）, and SlKr （t1/2-229,000 y）, are ideal tracers and can be detected by atom trap trace analysis （ATTA）, a laser-based technique, from environmental samples like air and groundwater. Prior to ATTA measurements, it is necessary to efficiently extract krypton and argon gases from samples. Using a combination of cryogenic distillation, titanium chemical reaction and gas chromatography, we demonstrate that we can recover both krypton and argon gases from 1-10 L ＂air-like＂ samples with yields in excess of 90% and 98%, respectively, which meet well the requirements for ATTA measurements. A group of testing samples are analyzed to verify the performance of the system, including two groundwater samples obtained from north China plain.展开更多
In the context of radioactive waste disposal,an underground research laboratory(URL)is a facility in which experiments are conducted to demonstrate the feasibility of constructing and operating a radioactive waste dis...In the context of radioactive waste disposal,an underground research laboratory(URL)is a facility in which experiments are conducted to demonstrate the feasibility of constructing and operating a radioactive waste disposal facility within a geological formation.The Meuse/Haute-Marne URL is a sitespecific facility planned to study the feasibility of a radioactive waste disposal in the Callovo-Oxfordian(COx)claystone.The thermo-hydro-mechanical(THM)behaviour of the host rock is significant for the design of the underground nuclear waste disposal facility and for its long-term safety.The French National Radioactive Waste Management Agency(Andra)has begun a research programme aiming to demonstrate the relevancy of the French high-level waste(HLW)concept.This paper presents the programme implemented from small-scale(small diameter)boreholes to full-scale demonstration experiments to study the THM effects of the thermal transient on the COx claystone and the strategy implemented in this new programme to demonstrate and optimise current disposal facility components for HLW.It shows that the French high-level waste concept is feasible and working in the COx claystone.It also exhibits that,as for other plastic clay or claystone,heating-induced pore pressure increases and that the THM behaviour is anisotropic.展开更多
基金suported by the National High Level Hospital Clinical Research Funding(2022-NHLHCRF-LX-02-03,2023-NHLHCRF-YXHZ-ZRZD-06)Ministry ofScience and Technology of the People's Republic ofChina,and National Natural Science Foundation ofChina(82071943,82273523).
文摘Background:To evaluate sex‐related differences in the risk factors associated with nonhealing or recurrence of hyper-thyroidism(NHRH)in patients with Graves'disease(GD)treated with radioactive iodine.Methods:In total,285 patients were enrolled.Data on radioactive iodine(RAI)dosage,ultrasound indexes of the thyroid,and other clinical factors were collected.Patients were divided into NHRH and non‐NHRH(hypothyroidism or euthyroidism)groups based on treatment outcomes.Univariate and multivariate weighted logistic regression analyses were used to identify factors associated with NHRH.Sex‐specific analyses of these risk factors were also conducted.Results:There were no significant differences between the two groups in terms of sex,thyroid shear wave elastography velocity values,or pretreatment serum free thyroxine(FT4)levels.Thyroid volume and age were independently associated with NHRH,with the odds of NHRH gradually decreasing as age increased.In subgroup analyses,both age and thyroid volume were independent risk factors for NHRH in female patients(p<0.05),while in male patients,only FT4 was independently associated with NHRH(p<0.05).Conclusions:In patients of different sexes,the influence of thyroid volume,age,and FT4 on treatment outcomes exhibits distinct patterns.
文摘Malignant tumours always threaten human health.For tumour diagnosis,positron emission tomography(PET)is the most sensitive and advanced imaging technique by radiotracers,such as radioactive^(18)F,^(11)C,^(64)Cu,^(68)Ga,and^(89)Zr.Among the radiotracers,the radioactive^(18)F-labelled chemical agent as PET probes plays a predominant role in monitoring,detecting,treating,and predicting tumours due to its perfect half-life.In this paper,the^(18)F-labelled chemical materials as PET probes are systematically summarized.First,we introduce various radionuclides of PET and elaborate on the mechanism of PET imaging.It highlights the^(18)F-labelled chemical agents used as PET probes,including[^(18)F]-2-deoxy-2-[^(18)F]fluoro-D-glucose([^(18)F]-FDG),^(18)F-labelled amino acids,^(18)F-labelled nucleic acids,^(18)F-labelled receptors,^(18)F-labelled reporter genes,and^(18)F-labelled hypoxia agents.In addition,some PET probes with metal as a supplementary element are introduced briefly.Meanwhile,the^(18)F-labelled nanoparticles for the PET probe and the multi-modality imaging probe are summarized in detail.The approach and strategies for the fabrication of^(18)F-labelled PET probes are also described briefly.The future development of the PET probe is also prospected.The development and application of^(18)F-labelled PET probes will expand our knowledge and shed light on the diagnosis and theranostics of tumours.
基金supported by the French National Agency for radioactive waste management(ANDRA).
文摘This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste.The fundamental background of thermo-poro-elastoplasticity theory is first summarized.The emphasis is put on the effect of pore fluid pressure on plastic deformation.A micromechanics-based elastoplastic model is then presented for a class of clayey rocks considered as host rock.Based on linear and nonlinear homogenization techniques,the proposed model is able to systematically account for the influences of porosity and mineral composition on macroscopic elastic properties and plastic yield strength.The initial anisotropy and time-dependent deformation are also taken into account.The induced cracking process is described by using a non-local damage model.A specific hybrid formulation is proposed,able to conveniently capture tensile,shear and mixed cracks.In particular,the influences of pore pressure and confining stress on the shear cracking mechanism are taken into account.The proposed model is applied to investigating thermo-hydromechanical responses and induced damage evolution in laboratory tests at the sample scale.In the last part,an in situ heating experiment is analyzed by using the proposed model.Numerical results are compared with experimental data and field measurements in terms of temperature variation,pore fluid pressure change and induced damaged zone.
基金supported by the National Major Scientific and Technological Special Project for“Significant New Drugs Development”(No.2018ZX09201018–028)the nuclear energy development projects of China during the 13thFive Year Plan periodthe key research and development project of the Sichuan Provincial Department of Science and Technology(No.18ZDYF1466)。
文摘Radioactive microspheres have demonstrated excellent therapeutic effects and good tolerance in the treatment of unresectable primary and secondary liver malignancies.This is attributed to precise embolization and potent anti-tumor effect.However,certain limitations such as unstable loading,perfusion stasis,heterogeneous distribution,ectopic distribution,and insufficient dosage,restrict their clinical application.Herein,a novel personalized Y-90 carbon microsphere with high uniformity,high specific activity and high availability(^(90)Y-HUACM)is presented.It is synthesized through planar molecular complex adsorption and chemical deposition solidification.^(90)Y-HUACM exhibited controllable size,excellent biocompatibility,outstanding in vitro and in vivo stability.The radiolabeling efficiency of Y-90 exceeded 99%and the leaching rate of Y-90 is far below 0.1%.Furthermore,the excellent anti-tumor effect,nuclide loading stability,anti-reflux characteristics,precise embolization,and biosafety of^(90)Y-HUACM were validated in a rabbit VX2liver tumor model.In summary,this new,high-performance,and customizable radioactive microsphere provides a superior choice for selective internal radiation treatment of advanced liver cancer is expected to be rapidly applied in clinical practice.
基金Supported by People's Livelihood Science and Technology Plan Joint Project of Liaoning Province,No.2021JH2/10300083。
文摘BACKGROUND Radiation enteritis is a common complication of radiation therapy in which the surrounding normal intestinal tissue is damaged by ionising radiation,and there is no standard pharmacological prophylaxis or treatment regimen available.Mesenchymal stem cell transplantation can be used for radiation protection and the treatment of acute radiation injury,but its therapeutic mechanism of action remains unclear.AIM To investigate the protective effects of autologous bone marrow-derived mesenchymal stem cell(ABMSC)transplantation on radiation-induced intestinal injury.METHODS A model of acute radioactive enteritis was established in dogs by applying abdominal intensity-modulated radiation at a single X-ray dose of 12 Gy.ABMSCs were transplanted into the mesenteric artery with the technology of femoral artery puncture and DSA imaging two days after radiation.Visual and histopathological changes of the experimental dogs were observed.Different kinds of cytokines from intestinal samples were tested using Quantibody Canine Cytokine Array method.Enzyme-linked immunosorbent assay(ELISA)was also used to evaluate the cytokines changes in serum.RESULTS The ABMSCs group showed significant improvements in survival status compared with the blank and saline treatment groups.Histological observations revealed that the former had lower histological scores than the later after treatment(P<0.05).Compared to the control groups,interleukin(IL)-10 and monocyte chemotactic protein(MCP)-1 from intestinal samples showed a remarkable increase and ELISA of serum samples proved higher secretion of the two target cytokines in the ABMSCs group(P<0.05).CONCLUSION Our data suggest that transplantation of ABMSCs promotes intestinal recovery after acute radioactive injury in Beagle dogs.The cytokines of IL-10 and MCP-1 might play an important role in this process.
文摘To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.The methods currently used for measuring dose rates are inadequate for obtaining the dose rates of key radionuclides and have large angular response errors when monitoring surface sources.To address this practical problem,this study proposes three methods for measuring the dose rate:the weighted peak total ratio,mean value regression,and numerical integration methods.These methods are based on energy-spectrum measurement data,and they were theoretically derived and numerically evaluated.Finally,a 1-m-long hexagonal radioactive surface source was integrated into a larger surface source.In situ measurement experiments were conducted on a large radioactive surface source using a dose-rate meter and a portable HPGespectrometer to analyze the errors of the three aforementioned methods and verify their validity.
文摘Alkaline igneous rocks represent one of the most economically important resources of radioactive minerals and rare metals.New field observations and petrographic studies are integrated with whole-rock geochemical analyses and Gamma ray spectroscopy data of alkaline rocks associated with the Amreit complex.The fieldwork was achieved by the collection of more than forty samples from alkaline granites and alkaline syenites.The youngest rocks cropping out in the study area are the cogenetic alkaline rocks,ranging from alkaline granite to alkaline syenite.These alkaline rocks are composed essentially of K-feldspar,alkali amphiboles(arfvedsonite),and sodic pyroxene,with accessories such as zircon,apatite,and ilmenite.Mineral characterization of the highly radioactive zones in both alkaline granite and alkaline syenite displays enrichment in monazite,thorite,zircon,ferro-columbite,xenotime,and allanite minerals.Geochemical analyses indicate that the Amreit rocks are alkaline with peralkaline affinity and have high concentrations of total alkalis(K_(2)O+Na_(2)O),large ion lithophile elements(LILEs;Ba and Rb),high field strength elements(HFSEs;Y,Zr and Nb),rare earth elements(REEs)and significantly depleted in K,Sr,P,Ti,and Eu,typically of post-collision A-type granites.Typically,the Amreit alkaline igneous rocks are classified as within plate granites and display A2 subtype characteristics.The fractionation of K-feldspars played a distinctive role during the magmatic evolution of these alkaline rocks.The geochemical characteristics indicate that the studied alkaline igneous rocks which were originated by fractional crystallization of alkaline magmas were responsible for the enrichment of the REE and rare metals in the residual melt.The high radioactivity is essentially related to accessory minerals,such as zircon,allanite,and monazite.The alkaline granite is the most U-and Thrich rock,where radioactivity level reaches up to 14.7 ppm(181.55 Bq/kg)e U,40.6 ppm(164.84 Bq/kg)e Th,whereas in alkaline syenite radioactivity level is 8.5 ppm(104.96 Bq/kg)e U,30.2 ppm(122.61 Bq/kg)e Th.These observations suppose that these alkaline rocks may be important targets for REEs and radioactive mineral exploration.
基金supported by the National Natural Science Foundation of China(Grant No.41972265)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2021-57)+1 种基金the Gansu Province Science Foundation(Grant No.20JR10RA492)Special thanks to the Environmental Research and Education Foundation for supporting the first author(Y.Tan)through a fellowship for his study at the University of Wisconsin-Madison.
文摘Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository.Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater,and was used to hydrate the blocks during the swelling pressure and swelling strain measurements,as Beishan is the most promising site for China's repository.Healing of the surface cracks was recorded by photography,and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks.The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater,but not affected by the drying cracks.The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks.The maximum swelling pressure measured in strong(i.e.high ion strength)Beishan groundwater was 44%of the pressure measured in deionized(DI)water,and the maximum swelling strain was reduced to 23%of the strain measured in DI water.Nevertheless,the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks,as demonstrated by the pictures of surface cracks and CT images.The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable(3.7×higher)to the hydraulic conductivity of the fresh block,indicating the self-healing of drying cracks after hydration and swelling in groundwater.A simplified method of protecting the block with plastic wraps before installation is recommended,since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.
基金supported by the French National Agency for radioactive waste management(ANDRA)and the National Natural Science Foundation of China(No.12202099).
文摘This paper addresses numerical analysis of thermo-hydromechanical processes in the context of deep geological disposal of radioactive waste.The emphasis is put on modeling of damaged zones induced by excavation,pore pressure and temperature changes.The theoretical background of thermo-poroelasticity for saturated porous media is first recalled.The framework for modeling initiation and evolution of induced cracks is then presented by using a variational approach of phase-field method.A specific model with two crack phase fields and considering thermo-hydromechanical interaction is proposed.A particular attention is paid on the description of shear cracks.The proposed model is implemented in the standard finite element method.An example of application is finally presented on the analysis of thermo-hydromechanical responses and cracked zones evolution around a typical disposal repository in the context of French concept for high level waste disposal.
文摘The deep geological repository for radioactive waste in Switzerland will be embedded in an approximately 100 m thick layer of Opalinus Clay.The emplacement drifts for high-level waste(approximately 3.5 m diameter)are planned to be excavated with a shielded tunnel boring machine(TBM)and supported by a segmental lining.At the repository depth of 900 m in the designated siting region Nordlich Lagern,squeezing conditions may be encountered due to the rock strength and the high hydrostatic pressure(90 bar).This paper presents a detailed assessment of the shield jamming and lining overstressing hazards,considering a stiff lining(resistance principle)and a deformable lining(yielding principle),and proposes conceptual design solutions.The assessment is based on three-dimensional transient hydromechanical simulations,which additionally consider the effects of ground anisotropy and the desaturation that may occur under negative pore pressures generated during the drift excavation.By addressing these design issues,the paper takes the opportunity to analyse some more fundamental aspects related to the influences of anisotropy and desaturation on the development of rock convergences and pressures over time,and their markedly different effects on the two lining systems.The results demonstrate that,regardless of these effects,shield jamming can be avoided with a moderate TBM overcut,however overstressing of a stiff lining may be critical depending on whether the ground desaturates.This uncertainty is eliminated using a deformable system with reasonable dimensions of yielding elements,which can also accommodate thermal strains generated due to the high temperature of the disposal canisters.
基金Project supported by the National Key R&D Program of China (2017YFE0106900)Key R&D Program of Jiangxi Province(20203BBG72W013)Fujian Program for High-Level Entrepreneurial and Innovative Talents Introduction。
文摘In the process of extracting ion-absorbed rare earth ore(IREO),the production of radioactive waste is a major environmental concern.To address this issue,MoS_(2) was used to modify ion-absorbed rare earth tailings(RET) to synthesize a novel MoS_(2)@RET composite material for the effective handling of radioactive waste generated in IREO separation industry.The composite material was thoroughly characterized using various analytical techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetry(TG),Fourier-transform infrared(FTIR),scanning electron microscopy(SEM),Brunaue r-Emmett-Teller(BET) and energy dispersive spectroscopy(EDS).By optimizing the operating parameters,the optimal experimental conditions were determined to be pH=3,contact time=60 min,liquid-solid ratio=6 g/L,and initial concentration=150 mg/L.The adsorption data fitted well with the pseudo second-order rate model.The thermodynamic parameters concerning the adsorption of Th(Ⅳ) were analyzed and computed.Langmuir isotherm model is a more fitting choice for the adsorption process compared to the Freundlich isotherm model.MoS_(2)@RET was used in the acid leachate of IREO waste residue,achieving the separation of Th and rare earth successfully.The mechanism of Th(Ⅳ) adsorption by MoS_(2)@RET was investigated,revealing that the adsorption process involves electrostatic interactions,chemical bonding,and redox reactions.The above research results indicate that MoS_(2)@RET composite materials have application potential in the sustainable treatment of IREO radioactive waste.
基金supported by the National Key R&D Program of China(No.2023YFA1606401)the National Natural Science Foundation of China(Nos.12135004,11635003 and 11961141004)the Guangxi Natural Science Foundation(No.2022GXNSFBA035549).
文摘Based on the dinuclear system model,the synthesis of the predicted double-magic nuclei^(298)Fl and 304120 was investigated via neutron-rich radioactive beam-induced fusion reactions.The reaction^(58)Ca+^(244)Pu is predicted to be favorable for producing^(298)Fl with a maximal ER cross section of 0.301 pb.Investigations of the entrance channel effect reveal that the^(244)Pu target is more promising for synthesizing^(298)Fl than the neutron-rich targets^(248)Cm and^(249)Bk,because of the influence of the Coulomb barrier.For the synthesis of 304120,the maximal ER cross section of 0.046 fb emerges in the reaction^(58)V+^(249)Bk,indicating the need for further advancements in both experimental facilities and reaction mechanisms.
文摘BACKGROUND Radioactive iodine-125(125I)microparticle therapy is a new type of internal radiation therapy that has shown unique advantages in the treatment of malignant tumors,especially hepatocellular carcinoma.Patients with hepatocellular carcinoma frequently experience portal vein embolism,which exacerbates the difficulty and complexity of treatment.125I particles,used in local radiotherapy,can directly act on tumor tissue and reduce damage to surrounding healthy tissue.Through retrospective analysis,this study discussed the efficacy and safety of radioactive 125I particles in portal vein embolization patients with hepatocellular carcinoma in order to provide more powerful evidence supporting clinical treatment.AIM To investigate the effect of transcatheter arterial chemoembolization combined with portal vein 125I particle implantation in the treatment of primary liver cancer patients with portal vein tumor thrombus and its influence on liver function.METHODS The clinical data of 96 patients with primary liver cancer combined with portal vein tumor thrombus admitted to our hospital between January 2020 and December 2023 were retrospectively analyzed.Fifty-two patients received treatment with transcatheter arterial chemoembolization and implantation of 125I particles in the portal vein(combination group),while 44 patients received treatment with transcatheter arterial chemoembolization alone(control group).The therapeutic effects on tumor lesions,primary liver cancer,and portal vein tumor embolisms were compared between the two groups.Changes in relevant laboratory indexes before and after treatment were evaluated.The t test was used to compare the measurement data between the two groups,and the χ^(2) test was used to compare the counting data between groups.RESULTS The tumor lesion response rate in the combination group(59.62%vs 38.64%)and the response rate of patients with primary liver cancer complicated with portal vein tumor thrombus(80.77%vs 59.09%)were significantly greater than those in the control group(χ^(2)=4.196,5.421;P=0.041,0.020).At 8 wk after surgery,the serum alpha-fetoprotein,portal vein main diameter,and platelet of the combined group were significantly lower than those of the control group,and the serum alanine aminotransferase,aspartate aminotransferase,and total bilirubin were significantly greater than those of the control group(t=3.891,3.291,2.330,3.729,3.582,4.126;P<0.05).The serum aspartate aminotransferase,alanine aminotransferase,and total bilirubin levels of the two groups were significantly greater than those of the same group 8 wk after surgery(P<0.05),and the peripheral blood platelet,alphafetoprotein,and main portal vein diameter were significantly less than those of the same group before surgery(P<0.05).CONCLUSION In patients with primary liver cancer and a thrombus in the portal vein,transcatheter arterial chemoembolization plus portal vein 125I implantation is more effective than transcatheter arterial chemoembolization alone.However,during treatment it is crucial to pay attention to liver function injury caused by transcatheter arterial chemoembolization.
文摘Clays and argillites are considered in some countries as possible host rocks for nuclear waste disposal at great depth.The use of compacted swelling clays as engineered barriers is also considered within the framework of the multi-barrier concept.In relation to these concepts,various research programs have been conducted to assess the thermo-hydro-mechanical properties of radioactive waste disposal at great depth.After introducing the concepts of waste isolation developed in Belgium,France and Switzerland,the paper describes the retention and transfer properties of engineered barriers made up of compacted swelling clays in relation to microstructure features.Some features of the thermo-mechanical behaviors of three possible geological barriers,namely Boom clay（Belgium）,Callovo-Oxfordian clay（France） and Opalinus clay（Switzerland）,are then described,including the retention and transfer properties,volume change behavior,shear strength and thermal aspects.
文摘The policy and principles on management of radioactive wastes are stipulated.Cement solidification and bituminization unit has come into trial run. Solid radioactive waste is stored in tentative storage vault built in each of nuclear faCilities. Seventeen storages associated with applications of nuclear technology and radioisotopes have been built for provinces. Disposal of low and intermediate level radioactive wastes pursues the policy of 'regional disposal'. Four repositories have been planned to be built in northwest, southwest, south and east China respectively. A program for treatment and disposal of high level radioactive waste has been made.
基金support from the China Atomic Energy Authority (CAEA) for China's URL Development Program and the Geological Disposal ProgramThe International Atomic Energy Agency is specially thanked for its support for China's geological disposal program through its Technical Cooperation Projects
文摘With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories（URLs） play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China＇s URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area,located in Gansu Province of northwestern China, has been selected as the final site for China＇s first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations,including borehole drilling,geological mapping, geophysical surveying,hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological,hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel（BET）, which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone（EDZ）, and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction.According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.
基金Supported by the China Atomic Energy Authority’s Special Program for Radioactive Waste Management and the International Atomic Energy Agency’s Technical Cooperation Project (IAE-TC Project CPR/9/026, CPR/4/024, CPR/3/008)
文摘For geological disposal of high-level radioactive waste （HLW）, the Chinese policy is that the spent nuclear fuel （SNF） should be reprocessed first, followed by vitrification and final disposal. The preliminary repository concept is a shaft-tunnel model, located in saturated zones in granite, while the final waste form for disposal is vitrified high-level radioactive waste. In 2006, the government published a long-term research and development （R＆D） plan for geological disposal of high-level radioactive waste. The program consists of three steps： （1） laboratory studies and site selection for a HLW repository （2006-2020）; （2） underground in-situ tests （2021-2040）; and （3） repository construction （2041-2050） followed by operation. With the support of China Atomic Energy Authority, comprehensive studies are underway and some progresses are made. The site characterization, including deep borehole drilling, has been performed at the most potential Beishan site in Gansu Province, Northwestern China. The data from geological and hydrogeological investigations, in-situ stress and permeability measurements of rock mass are presented in this paper. Engineered barrier studies are concentrated on the Gaomiaozi bentonite. A mock-up facility, which is used to study the thermo-hydro-mechano-chemical （THMC） properties of the bentonite, is under construction. Several projects on mechanical properties of Beishan granite are also underway. The key scientific challenges faced with HLW disposal are also discussed.
基金supported by Wu Zuze Science and Technology Development Foundation of Beijing
文摘Objective:To test the curative effect of human umbilical cord-derived mesenchymal stem cells on rat acute radioactive enteritis and thus in provide clinical therapeutic basis for radiation sickness.Methods:Human umbilical cord-derived mesenchymal stem cells were cultivated in vitro and the model of acute radioactive enteritis of rats was established.Then,the umbilical cord mesenchymal stem cells were injected into the rats via tail vein.Visual and histopathiological changes of the experimental rats were observed.Results:After the injection,the rats in the prevention group and treatment group had remarkably better survival status than those in the control group.The histological observations revealed that the former also had better intestinal mucosa structure,more regenerative cells and stronger proliferation activity than the latter.Conclusions:Human umbilical cord-derived mesenchymal stem cells have a definite therapeutic effect on acute radioactive enteritis in rats.
基金This work was supported by the Special Fund for Land and Resources Research in the Public Interest （No.201511046） and the National Natural Science Foundation of China （No.21225314 and No.41102151）. We would like to give our gratitude to Zong-yu Chen from IHEG for organizing the field campaign.
文摘Radioactive noble-gas isotopes, SSKr （half-life tl/2=10.8 y）, 39Ar （tl/2=269 y）, and SlKr （t1/2-229,000 y）, are ideal tracers and can be detected by atom trap trace analysis （ATTA）, a laser-based technique, from environmental samples like air and groundwater. Prior to ATTA measurements, it is necessary to efficiently extract krypton and argon gases from samples. Using a combination of cryogenic distillation, titanium chemical reaction and gas chromatography, we demonstrate that we can recover both krypton and argon gases from 1-10 L ＂air-like＂ samples with yields in excess of 90% and 98%, respectively, which meet well the requirements for ATTA measurements. A group of testing samples are analyzed to verify the performance of the system, including two groundwater samples obtained from north China plain.
文摘In the context of radioactive waste disposal,an underground research laboratory(URL)is a facility in which experiments are conducted to demonstrate the feasibility of constructing and operating a radioactive waste disposal facility within a geological formation.The Meuse/Haute-Marne URL is a sitespecific facility planned to study the feasibility of a radioactive waste disposal in the Callovo-Oxfordian(COx)claystone.The thermo-hydro-mechanical(THM)behaviour of the host rock is significant for the design of the underground nuclear waste disposal facility and for its long-term safety.The French National Radioactive Waste Management Agency(Andra)has begun a research programme aiming to demonstrate the relevancy of the French high-level waste(HLW)concept.This paper presents the programme implemented from small-scale(small diameter)boreholes to full-scale demonstration experiments to study the THM effects of the thermal transient on the COx claystone and the strategy implemented in this new programme to demonstrate and optimise current disposal facility components for HLW.It shows that the French high-level waste concept is feasible and working in the COx claystone.It also exhibits that,as for other plastic clay or claystone,heating-induced pore pressure increases and that the THM behaviour is anisotropic.
