Carbon Composites for the Immobilization of Long-Lived Radio-Nuclides for the Purpose Their Disposal and Transmutation, Part 1

There is presented the review of publications connecting with creation of matrices for the immobilization of long-lived radionuclides and radioactive waste for storage and disposal, as well as for the transmutation. This paper substantiates the practicability and feasibility of obtaining the carbon matrces by carbonization of imidoderivatives.

Activation Cross Sections for Generation of Long-Lived Radionuclides

A summary is given on the activation cross section measurements performed byChina Institute of Atomic Energy（CIAE）,Lanzhou University（LU）,Peking University（PU）and Sichuan University（SU）from 1989 to 1994 for generation of long-lived radionuclides of im-portance in fusion reactor technology.The cross sections are measured for the reactions 109Ag（n,2n）108Agm,151Eu（n,2n）150Eum,153Eu（n,2n）152Eu8,159Tb（n,2n）158Tb,179Hf（n,2n ）178Hfm2,182W（n,n′α）178Hfm2,187Re（n,2n）186Rem and 193Ir（n,2n）192Irm2at 14 MeV,109Ag（n,2n）108Agm,151Eu（n,2n）150Eum,159Tb（n,2n）158Tb and 179Hf（n,2n）178Hfm2at 9.5 and 9.9 MeV,and98Mo（n,γ）199Mo（β-）→99Tc,165Ho（n.γ）166Hom and 151Eu（n,γ）152Eu8 in the energy range of20～1100 keV.Some of them were calculated by systematic and HFTT code,which was basedon the compound nucleus evaporation and the preequilibrium exciton model.

Nondestructive technique for identifying nuclides using neutron resonance transmission analysis at CSNS Back-n

Nondestructive and noninvasive neutron assays are essential applications of neutron techniques.Neutron resonance transmission analysis(NRTA)is a powerful nondestructive method for investigating the elemental composition of an object.The back-streaming neutron line(Back-n)is a newly built time-of-flight facility at the China Spallation Neutron Source(CSNS)that provides neutrons in the eV to 300 MeV range.A feasibility study of the NRTA method for nuclide identification was conducted at the CSNS Back-n via two test experiments.The results demonstrate that it is feasible to identify different elements and isotopes in samples using the NRTA method at Back-n.This study reveals its potential future applications.

Theoretical analysis of long-lived radioactive waste in pressurized water reactor

Background The accelerator-driven subcritical transmutation system(ADS)is an advanced technology for the harmless disposal of nuclear waste.A theoretical analysis of the ingredients and content of nuclear waste,particularly long-lived waste in a pressurized water reactor(PWR),will provide important information for future spent fuel disposal.Purpose The present study is an attempt to investigate the yields of isotopes in the neutron-induced fission process and estimate the content of long-lived ingredients of nuclear waste in a PWR.Method We combined an approximation of the mass distribution of five Gaussians with the most probable charge model(Zp model)to obtain the isotope yields in the^(235)U(n,f)and^(239)Pu(n,f)processes.The potential energy surface based on the concept of a di-nuclear system model was applied to an approximation using five Gaussian functions.A mathematical formula for the neutron spectrum in a PWR was established,and sets of differential equations were solved to calculate the content of long-lived nuclides in a PWR.Results The calculated isotopic fission yields were in good agreement with the experimental data.Except for 238U,the contents of^(239)Pu,^(240)Pu,^(241)Pu,^(242)Pu,^(237)Np,^(235)U,and^(236)U are predominant in the PWR after reaching a discharge burnup.In addition,some isotope pairs of heavy nuclei reach a similar value after stabilization,which can be explained by the decay chain and effective fission crosssections.For fission fragments,we simulated the content evolution of some long-lived nuclides^(90)Sr,^(107)Pd,^(135)Cs,and their isobars^(90)Rb,^(107)Rh,and^(135)Xe during a fuel cycle in a PWR.The variations in the inventories of uranium and plutonium were in good agreement with the data in Daya Bay.Conclusion A new method is proposed for the prediction of the isotopic fission yield.The inventory of long-lived nuclides was analyzed and predicted after reaching a discharge burnup.

Determining topographic shielding from digital elevation models for cosmogenic nuclide analysis: a GIS model for discrete sample sites

Topographic shielding(TS) is an important factor in cosmogenic nuclide surface exposure dating. The development of geographic information systems(GIS) and the availability of digital elevation models(DEMs) make it possible to derive this factor directly from a DEM. Most available GIS models derive the TS factors for an area(all cells in a DEM) without the consideration of surface conditions of individual sites, such as the strike, dip,and height above ground, into the calculation. This paper presents a new GIS model to derive the TS factors for discrete sample sites. This model uses the Skyline and Skyline Graph functions in ArcGIS to extract the set of azimuth and elevation angles of topographic obstructions around each site from a DEM(considering the sample height above ground)and then incorporates the strike and dip information of the sample surface to derive the TS factor. All processing tools and steps are streamlined in ArcGIS modelbuilder and this model can be run like a standard ArcGIS geoprocessing tool. It provides an easy and user-friendly means to derive the TS factors for discrete samples based on a DEM and the measured strike, dip and sample height for each site.

Determining Topographic Shielding from Digital Elevation Models for Cosmogenic Nuclide Analysis:a GIS Approach and Field Validation

Topographic shielding of cosmic radiation flux is a key parameter in using cosmogenic nuclides to determine surface exposure ages or erosion rates. Traditionally, this parameter is measured in the field and uncertainty and/or inconsistency may exist among different investigators. This paper provides an ArcGIS python code to determine topographic shielding factors using digital elevation models （DEMs）. This code can be imported into ArcGIS as a geoprocessing tool with a user-friendly graphical interface. The DEM-derived parameters using this method were validated with field measurements in central Tian Shan. Results indicate that DEM-derived shielding factors are consistent with field-measured values. It provides a valuable tool to save fieldwork efforts and has the potential to provide consistent results for different regions in the world to facilitate the comparison of cosmogenie nuclide results.

Comparative Proteomic Analysis of Human Benign Prostatic Hyperplastic Tissue Before and After Irradiation with Radioactive Nuclide

The expressed proteins were extracted from human benign prostatic hyperplastic tissues obtained with transurethral resection of the prostate before and after their irradiation with radioactive nuclide. The proteins were separated by two-dimensional gel electrophoresis and analyzed by mass spectrometry. Four proteins were differentially expressed and were identified with a database search. Three were associated with the regulation of cell motion and one was lactate dehydrogenase B, which plays an important role in the process of cell energy metabolism and cell state changes in tissue. The comparative proteomic analysis indicates that after irradiation with radioactive nuclide, changes occur in human benign prostatic hyperplastic cells, and associated proteins are expressed. Analysis of these proteins should help to identify the mechanism involved when human prostatic hyperplasia is treated by irradiation with radioactive nuclide.

Fast nuclide identification based on a sequential Bayesian method

The rapid identification of radioactive substances in public areas is crucial.However,traditional nuclide identification methods only consider information regarding the full energy peaks of the gamma-ray spectrum and require long recording times,which lead to long response times.In this paper,a novel identification method using the event mode sequence(EMS)information of target radionuclides is proposed.The EMS of a target radionuclide and natural background radiation were established as two different probabilistic models and a decision function based on Bayesian inference and sequential testing was constructed.The proposed detection scheme individually processes each photon.When a photon is detected and accepted,the corresponding posterior probability distribution parameters are estimated using Bayesian inference and the decision function is updated.Then,value of the decision function is compared to preset detection thresholds to obtain a detection result.Experiments on different target radionuclides(137Cs and 60Co)were performed.The count rates of the regions of interest(ROI)in the backgrounds between[651,671],[1154,1186],and[1310,1350]keV were 2.35,5.14,and 0.57 CPS,respectively.The experimental results demonstrate that the average detection time was 6.0 s for 60Co(with an activity of 80400 Bq)at a distance of 60 cm from the detector.The average detection time was 7 s for 137Cs(with an activity of 131000 Bq)at a distance of 90 cm from the detector.The results demonstrate that the proposed method can detect radioactive substances with low activity.

Yield of long-lived fission product transmutation using proton-, deuteron-, and alpha particle-induced spallation

The transmutation of long-lived fission products through spallation induced by light nuclides was investi-gated for the purpose of determining the feasibility of this approach for long-lived fission products,in both economic and environmental terms.The cross-section data were obtained from the TALYS Evaluated Nuclear Data Library(TENDL).A thick target model was used to study the consumption of the target isotopes in the transmutation process.The transmutation yield was calculated using the highest beam intensity available with the China initiative accelerator-driven system.It was found that the light nuclide-induced spallation reaction can significantly reduce the radio toxicity of the investigated long-lived fission products.Using the transmutation target made of elemental LLFP and the proton beam with an intensity of 5 mA,the consumption of 90 Sr,93 Zr,107 Pd,or 137 Cs can reach approximately 500 g per year.

Efficient and selective extraction of uranium from seawater based on a novel pulsed liquid chromatography radionuclide separation method

The novel pulsed liquid chromatography radionuclide separation method presented here provides a new and promising strategy for the extraction of uranium from seawater.In this study,a new chromatographic separation method was proposed,and a pulsed nuclide automated separation device was developed,alongside a new chromatographic column.The length of this chromatographic column was 10 m,with an internal warp of 3 mm and a packing size of 1 mm,while the total separation units of the column reached 12,250.The most favorable conditions for the separation of nuclides were then obtained through optimizing the separation conditions of the device:Sample pH in the column=2,sample injection flow rate=5.698 mL/min,chromatographic column heating temperature=60℃.Separation experiments were also carried out for uranium,europium,and sodium ions in mixed solutions;uranium and sodium ions in water samples from the Ganjiang River;and uranium,sodium,and magnesium ions from seawater samples.The separation factors between the different nuclei were then calculated based on the experimental data,and a formula for the separation level was derived.The experimental results showed that the separation factor in the mixed solution of uranium and europium(1:1)was 1.088,while achieving the initial separation of uranium and europium theoretically required a 47-stage separation.Considering the separation factor of 1.50for the uranium and sodium ions in water samples from the Ganjiang River,achieving the initial separation of uranium and sodium ions would have theoretically required at least a 21-stage separation.Furthermore,for the seawater sample separation experiments,the separation factor of uranium and sodium ions was 1.2885;therefore,more than 28 stages of sample separation would be required to achieve uranium extraction from seawater.The novel pulsed liquid chromatography method proposed in this study was innovative in terms of uranium separation and enrichment,while expanding the possibilities of extracting uranium from seawater through chromatography.

DEPTH PROFILING OF RADIOACTIVE NUCLIDES IN SOIL

Analyses of 114 soil samples in Ningbo City show that,in general,there are statistical differences of 137Cs and 40K contents between every layers,the other kinds of natural radionuclides present an increasing tendency with depth.When the γ radiation dose rate is estimated by Beck Formula,owing to the effect of those nonuniform distributions is less than 1% and can be ignored.'

Observation of Molybdenum Emission from Impurity-Induced Long-Lived m=1 Mode on the Experimental Advanced Superconducting Tokamak

We observe the spectra of molybdenum for the first time since the first wall of our experimental advanced superconducting tokamak （EAST） was changed mainly to molybdenum tiles. A large amount of molybdenum accumulated in the central plasma where the long-lived m = 1 mode instability bursts is shown. Molybdenum is proved to be the main impurity species observed during the formation and lifetime of impurity-induced long-lived m= 1 mode. This may indicate that a close relationship exists between the high-Z impurity accumulation and the occurrence of long-lived m = 1 mode in EAST plasmas.

Simulation of experimental spectra for medium-heavy nuclides in accelerator mass spectrometry

Some interferences are often encountered in accelerator mass spectrometry (AMS) measurements, espe-cially for medium-heavy nuclide measurement. It is difficult for online discrimination of the nuclide of interest from the interfering ones. In order to solve this problem, we developed a method to simulate the experimental spectra of medium-heavy nuclides in AMS measurements. The results obtained from this method are in good agreement with experimental values.

Amazing long-lived lifetime

Bulk thanks to their characteristics of being environmentally benign,easily fabricated and relatively stable,dyesensitized solar cells(DSSCs)have attracted attention over decades as a potential alternative to solar energy conversion[1].However,as L.M.Peter pointed out in 2011,'although much more is now known about the physical and chemical processes taking place during operation of the DSSCs,the exponential increase in research effort during this period has not been matched by large increases in efficiency'[2].To date,

Theoretical Study of Nonclassical Platinum Complexes Bonding to Purine Bases: How the Long-lived Monofunctional Adducts Can Be in Existence?

The B3LYP/6-31G^＊ level of theory was used for the optimization of nonclassical platinum drugs with planar aromatic heterocycle ligands in addition to their monoaqua species, diaqua species and monofunctional adducts. Single point calculations were performed on optimized geometries using the MP2/6-31G^＊＊ method, and the Lanl2dz pseudo potential for the Pt atom remained constant in all calculations. It can be easily seen that the trans effect can influence both geometrical structures and bond dissociating energies （BDEs）. On the basis of our calculation, we get that the long-lived monofunctional adducts with chloride ligand may be in existence, because they possessed higher stability energies, easily dissociated chloride compared with the monoaqua species dissociating chloride and that replacement of the first chloride by bases became exothermic in solution. Our calculated results also demonstrate that the strongest H-bonds appear in the complexes of q-wG and t-wG using different methods. In comparison with adenine complexes, the corresponding guanine complexes possess larger interaction energies as well as higher stability energies either corrected by basis set superposition error （bsse） of Boys-Bernardi counterpoise method or uncorrected both in gas phase and in solution with one exception that the stability energy of q-CIA complex in solution is larger than that of q,CIG complex. Finally, the nature of bond was analyzed in terms of partial charges distribution based on NBO population.

Theoretical Study on the Long-lived Complexes for the Na +I_2Collision System

For the Na + I2 collision system, theoretical study is performed on the QCISD(T) level by using ab initio method. The ab initio potential energy surfaces are got and on them the long-lived complexes are found and optimized. These results verify the crossed molecule beam experimental phenomenon and the detailed geometry structures are given for the first time. The role of the complexes in the reaction path is also described in detail.

Study and Proposal to Build the Maintenance Systematization for Preservation of Buildings Aiming at Long-Lived Buildings

Systematization for the maintenance of buildings enables their supporting system to be more practical than before. This study aims to make the maintenance and the long-term repairs for the buildings to be easier. In Japan, 30-40-year-old buildings seem to have been planned and built with little thought about their future maintenances, which have made them very difficult to be repaired on a large scale. This is why effective management systems about dealing with the data should be strongly suggested. Since the Building Standard Law was amended on April 1, 2008, in Japan, the regular investigation and report for particular buildings are legally obligated every three years, thus a variety of useful data can be obtained through Kitakyushu City cases as well as former data personally obtained. With those data used usefully, systematization for the maintenance of the buildings will produce satisfactory results by building up a connection between those data and the long-term repair planning.

Long-lived neutron-induced radioisotopes in OKTAVIAN facility concrete wall after 38 year-operation

An intense 14 MeV neutron source facility named OKTAVIAN was installed in the A15 building,Osaka University in 1981.Along the operation period,new radioisotopes with various half-life have been produced as neutron activation products in its concrete wall shield.In this work,we investigated the concrete wall in the heavy irradiation room of OKTAVIAN using gamma spectrometry method to discover the presence of radioisotope having large half-life value(long-lived radioisotope)as neutron activation products.Computational simulations were performed prior to measurement to predict the presence of long-lived radioisotopes by employing MCNP5 and FISPACT codes.A pre-calibrated Germanium detector with high energy resolution was employed to measure the concrete.Several long-lived activation products have been observed such as 152 Eu,54 Mn,65 Zn,22 Na and 60 Co.The activity of each radioisotope was derived after estimating the detector efficiency using MCNP5.As a result of the measurement and analysis,the followings are concluded:(1)Though presence of activation products represents radiological risk to everyone who performs an experimental activity in the irradiation room of the OKTAVIAN facility,the present result shows that past experiments were carried out safely without any significant additional exposure dose coming from the wall for the last 38 years.(2)The approximated total fluence of D-T neutrons to the wall was successfully estimated from the produced radioisotope,152 Eu,because it has the longest half-life of 13.5 years among the observed radioisotopes.(3)From the results of(1)and(2),it could be possible to estimate the total activity of the concrete wall in the OKTAVIAN facility,which is very essential and important information,because this would be very valuable for decommissioning or disposal of the facility in the future.

Experimental Results on Excess Heat Power, Impurity Nuclides and X-Ray Production in Experiments with a High-Voltage Electric Discharge System

It reviewed results on low-energy nuclear reaction （LENR） processes in a high-voltage （1,000-4,000 V） electric discharge system. The experimental results are divided into three sets： excess heat measurements; yield of impurity nuclides （nuclear ash）; X-ray measurements. Up to 8 W of excess power was observed, with a power gain of up to 170% was seen in glow discharge experiments. Up to 300 W of excess power, with a power gain up to 340% was observed in experiments using a high-voltage electrolysis cell. The impurity nuclide yield showing a shift of up to a few per cent from natural isotopic abundances was detected by spark mass spectrometry, by secondary ionic mass spectrometry, and by secondary neutral mass spectrometry. X-ray emission in the range of 0.6-6.0 keV, has been observed. Based on these experimental results we propose a phenomenological model for LENR based on the interaction of an electric discharge with condensed matter （of the cathode）.

Predicting the Binding Energies of the 1s Nuclides with High Precision, Based on Baryons which Are Yang-Mills Magnetic Monopoles

In an earlier paper, the author employed the thesis that baryons are Yang-Mills magnetic monopoles and that proton and neutron binding energies are determined based on their up and down current quark masses to predict a relationship among the electron and up and down quark masses within experimental errors and to obtain a very accurate relationship for nuclear binding energies generally and for the binding of 56Fe in particular. The free proton and neutron were understood to each contain intrinsic binding energies which confine their quarks, wherein some or most (never all) of this energy is released for binding when they are fused into composite nuclides. The purpose of this paper is to further advance this thesis by seeing whether it can explain the specific empirical binding energies of the light 1s nuclides, namely, 2H, 3H, 3He and 4He, with high precision. As the method to achieve this, we show how these 1s binding energies are in fact the components of inner and outer tensor products of Yang-Mills matrices which are implicit in the expressions for these intrinsic binding energies. The result is that the binding energies for the 4He, 3He and 3H nucleons are respectively, independently, explained to less than four parts in one million, four parts in 100,000, and seven parts in one million, all in AMU. Further, we are able to exactly relate the neutron minus proton mass difference to a function of the up and down current quark masses, which in turn enables us to explain the 2H binding energy most precisely of all, to just over 8 parts in ten million. These energies have never before been theoretically explained with such accuracy, which leads to the conclusion that the underlying thesis provides the strongest theoretical explanation to date of what baryons are, and of how protons and neutrons confine their quarks and bind together into composite nuclides. As is also reviewed in Section 9, these results may lay the foundation for more easily catalyzing nuclear fusion energy release.