WorldWideScience

Sample records for active inspection fission

  1. Active inspection fission signatures for the detection, quantification and identification of fissionable materials

    Recently there has been heightened interest in active inspection techniques that can nondestructively detect, identify and quantify fissionable materials for security, nonproliferation and nuclear forensics applications. These active techniques use a source of neutrons or high energy photons to stimulate nuclear reactions in the inspection object and then monitor the emitted secondary radiation for unique fissionable material signatures. These signatures are based on detecting emissions from fission reactions (e.g., prompt and delayed neutrons) and/or non fission reactions (e.g., nuclear resonance fluorescence). In this presentation, the authors will present recent experimental results using prompt neutrons, delayed neutrons and delayed γ rays as fissionable material signatures. The research first focused on how to detect these emissions in an intense radiation environment and the algorithms required to produce unique fissionable material signatures. The sensitivity, accuracy, speed and isotope specificity of each signature was then explored. Current work is focusing on how to effectively combine multiple signatures. (author)

  2. Calculation code of the fission products activity

    The document describes the two codes for the calculation of the fission products activity. The ''Pepin le bref'' code gives the exact value of the beta and gamma activities of completely known fission products. The code ''Plus Pepin'' introduces the beta and gamma activities whose properties are partially known. (A.L.B.)

  3. Food Service Establishment Inspections: Beginning 2005 (ACTIVE)

    U.S. Department of Health & Human Services — This data includes the name and location of active food service establishments and the violations that were found at the time of the inspection. Active food service...

  4. Inspection of licensee - Maintenance programme and activities

    An effective maintenance programme is critical to sustained safe and reliable operation of nuclear power plants. The Working Group on Inspection Practices (WGIP) concluded that when a licensee has an effective maintenance programme, the overall operating safety of the plant is improved and the protection of public health and safety enhanced. All Regulatory Bodies (RB) consider maintenance to be an important area for oversight. Although a variety of inspection practices are being used; RB are actively monitoring licensee performance. Specifically the following conclusions were reached and commendable practices identified: - Maintenance oversight by regulators appears to be in a stable continuous improvement state. Most regulators are executing inspection oversight based on an existing regulatory framework. - The performance of a licensee's maintenance programme is recognized as important part of maintaining nuclear safety. The result of the maintenance program assessment is included in the overall performance assessment of a license. - Maintenance inspection activities are recognized as an important part of the regulatory oversight process. Inspection activities are based on the safety significance and nature of work being performed by the licensee. - The effectiveness of the maintenance inspection activities is recognized to rely on properly qualified inspectors; who are adequately supported by specialists. Training and qualification of inspectors should be based on how the RB reviews and inspects licensee maintenance programmes. - Reporting requirements are identified to provide information on the licensees maintenance programme, and to help guide inspection activities. - Performance Indicators are recognized as a useful tool for helping focus regulatory activities. Basic PI are identified and tracked by the RB, and use of PI by the licensee is monitored. - Inspections are designed to confirm that the licensee is planning and scheduling maintenance with due

  5. Fission investigations and evaluation activities at IRMM

    The IRMM has a longstanding tradition in the field of neutron induced fission physics studies. It is especially well equipped with world-class facilities as the high resolution neutron time-of-flight spectrometer GELINA and the 7 MV Van de Graaff accelerator for the quasi-monoenergetic neutron production. During the past decade several neutron induced fission reactions have been studied in the energy range from eV up to 6 MeV and spontaneous fission. The isotopes under investigation were 235,238 U(n,f), 239 Pu(n,f), 237 Np(n,f), 252 Cf(SF) and 233 Pa(n,f). For all isotopes but 233 Pa, the fission fragment mass-yield and total kinetic energy distributions were measured. 233 Pa was only investigated for the fission cross-section. The results have been described within the multi-modal fission model. The three most dominant fission modes, the two asymmetric standard I (S1) and standard II (S2) as well as the the symmetric superlong mode were used for all the isotopes but 252 Cf. For this isotope at least one other fission mode had to be taken into account, the so--called standard III (S3) mode. Since the theoretical interpretation of experimental results was rather successful also an attempt was made to improve the evaluation of the respective fission cross-section as well as their neutron multiplicities and spectra. Here, the statistical model for fission cross-section evaluation was extended by including the multi-modality concept for fission. Based on the underlying model, separate outer fission barriers have been considered for each mode, while the inner barriers and isomeric wells are assumed to be the same. The self-consistent calculations of the fission cross-section as well as total, capture, elastic and inelastic cross-sections were in good agreement with the experimental data and evaluated nuclear data libraries. As a side product, also fission fragment mass yield distributions have been deduced at incident neutron energies hitherto unaccessible. Very

  6. Inspection of licensee activities in emergency planning

    The CNRA believes that safety inspections are a major element in the regulatory authority's efforts to ensure the safe operation of nuclear facilities. Considering the importance of these issues, the Committee has established a special Working Group on Inspection Practices (WGIP). The purpose of WGIP, is to facilitate the exchange of information and experience related to regulatory safety inspections between CNRA Member countries Following discussions at several meetings on the topic of what is expected by the regulatory body regarding inspection criteria, WGIP proposed putting together a compilation of Member countries practices on regulatory inspection practices with respect to licensee emergency planning. CNRA approved this task and this report. Information was collected from a questionnaire which was issued in 1996. The report presents information on regulatory inspection activities with respect to emergency planning in NEA Member countries. The focus of the report is on the third section. It reviews the similarities and differences in inspection practices to evaluate compliance with the requirements over which the regulatory body (RB) has jurisdiction

  7. Improved Fission Neutron Data Base for Active Interrogation of Actinides

    Pozzi, Sara; Czirr, J. Bart; Haight, Robert; Kovash, Michael; Tsvetkov, Pavel

    2013-11-06

    This project will develop an innovative neutron detection system for active interrogation measurements. Many active interrogation methods to detect fissionable material are based on the detection of neutrons from fission induced by fast neutrons or high-energy gamma rays. The energy spectrum of the fission neutrons provides data to identify the fissionable isotopes and materials such as shielding between the fissionable material and the detector. The proposed path for the project is as follows. First, the team will develop new neutron detection systems and algorithms by Monte Carlo simulations and bench-top experiments. Next, They will characterize and calibrate detection systems both with monoenergetic and white neutron sources. Finally, high-fidelity measurements of neutron emission from fissions induced by fast neutrons will be performed. Several existing fission chambers containing U-235, Pu-239, U-238, or Th-232 will be used to measure the neutron-induced fission neutron emission spectra. The challenge for making confident measurements is the detection of neutrons in the energy ranges of 0.01 – 1 MeV and above 8 MeV, regions where the basic data on the neutron energy spectrum emitted from fission is least well known. In addition, improvements in the specificity of neutron detectors are required throughout the complete energy range: they must be able to clearly distinguish neutrons from other radiations, in particular gamma rays and cosmic rays. The team believes that all of these challenges can be addressed successfully with emerging technologies under development by this collaboration. In particular, the collaboration will address the area of fission neutron emission spectra for isotopes of interest in the advanced fuel cycle initiative (AFCI).

  8. RPII Inspection and Licensing Activities and Annual Inspection Programme for 2013

    The objective of this report is to provide an overview of inspection activities of the Radiological Protection Institute of Ireland RPII, to examine the evolution in licensee numbers and to outline the rationale in developing annual inspection programmes. All inspection activities are now carried out within the framework of a quality management system including inspection planning, the training of inspectors, the conduct of inspections as well as post inspection follow up and review. This report also provides an overview of the main features of the quality system

  9. Comparison of activation in fission and fusion spectrum neutron beams

    The materials used in the construction of fusion reactors have to satisfy a number of criterions, one of the important being low activation due to neutron irradiation. Experimental analysis of the activation of candidate materials for the first wall is performed with the irradiation of samples in various neutron fields, frequently in the field of a fission reactor. In the present work a calculation is performed to compare the expected activation of candidate materials intended to be used for the first wall in fusion reactors with the activation of a sample of the same material in a fission reactor beam. The FISPACT code is used for activation calculations. An investigation, to what extent the results of activation in a fission spectrum neutron beam, where most neutrons have energies of less than 2 MeV, mimic the real situation in a fusion reactor with the peak neutron energy around 14 MeV, is performed. (author)

  10. On the potential of active coincidence counting using a spontaneous fission source to induce fission

    Using the one-group point-model equations as a guide, we compare the active neutron Doubles rate from a multiplying item interrogated with a spontaneous fission neutron source with that of a random neutron source of equal emission rate. We find that, especially for highly multiplying items, 252Cf is likely to provide a viable alternative to the commonly used Am/Li interrogation source. We conclude that detailed design studies and experiments are warranted to develop this concept into practical assay tools. Keywords: coincidence counting; active interrogation; 252Cf active driver; point-model; collar detector

  11. Developing inspection strategies to support local activities

    Jensen, Per Langå

    2003-01-01

    An analysis of the Danish development in regulatory praxsis within occupational health and safety with a detailed description of Adapted Inspection.......An analysis of the Danish development in regulatory praxsis within occupational health and safety with a detailed description of Adapted Inspection....

  12. Irradiation effects upon activities of fission product iodine

    This report describes the experimental study of the irradiation effects upon activities of fission product iodine made in the period from June, 1981 to March, 1982. Chemical transport of iron was studied under irradiation of cesium iodide by electron beam. Deposited ion was identified on the high temperature surface, which can be taken to certify the appropriateness of the model of the iodine-including chemical transport of stainless-steel cladding components to fuel in the LMFBR fuel pins. (author)

  13. Telomerase activation after recruitment in fission yeast.

    Armstrong, C. A.; Pearson, S R; Amelina, H.; Moiseeva, V.; Tomita, K.

    2014-01-01

    Summary Current models depict that telomerase recruitment equates to activation. Telomeric DNA-binding proteins and the telomerase accessory proteins coordinate the recruitment of telomerase to the ends of chromosomes in a telomere length- and cell-cycle-dependent manner [1–4]. Recent studies have demonstrated that the telomeric protein TPP1 and its binding protein TIN2 are key proteins for both telomerase recruitment and processivity in mammalian cells [5–7]. Although the precise molecular m...

  14. Delayed fission

    Delayed fission is a nuclear process that couples beta decay and fission. In the delayed fission process, a parent nucleus undergoes beta decay or electron capture and thus populates excited states in the daughter nucleus. This review covers experimental methods for detecting and measuring delayed fission. Experimental results (ECDF activities and beta-DF activities) and theory are presented. The future prospects for study of delayed fission are discussed. 50 refs., 8 figs., 2 tabs

  15. Fission and spallation data evaluation using induced-activity method

    Karapetyan, G S

    2015-01-01

    The induced-activity investigations in off-line analysis performed in different experiments, concerning pre-actinide and actinide nuclei, are here presented and discussed. Generalized expressions for the determination of independent yields/cross sections of radioactive nuclei, formed in the targets, are derived and analysed. The fragment mass distribution from U-238, Th-232 and Ta-181 photofission at the bremsstrahlung end-point energies of 50 and 3500 MeV, and from Am-241, U-238 and Np-237 fission induced by 660-MeV protons, are scrutinized from the point of view of the multimodal fission approach. The results of these studies are hence compared with theoretical model calculations using the CRISP code. We subsequently discuss the complex particle-induced reaction, such as heavy-ions and deuterons, by using the thick-target thick-catcher technique and the two-step vector model framework as well. This is accomplished in order to present the investigation of the main processes (fission, spallation and (multi)fr...

  16. U.S. Industry Activities on Inspection of CRDM Penetrations

    The discovery of primary water stress corrosion cracking (PWSCC) in control rod drive mechanisms (CRDM) penetrations in U.S. and European plants prompted the U.S. nuclear industry to focus considerable effort on development and implementation of effective inspection methods. In particular, cracking was discovered in butt welds connecting reactor vessel nozzles to main coolant piping and in control rod drive mechanism (CRDM) head penetration base material and attachment welds. The EPRI Materials Reliability Program (EPRI-MRP) formed an Inspection Committee to address development of industry guidance for inspection of these components, development of effective non-destructive examination (NDE) methods, and demonstration of inspection processes. This paper discusses the MRP activities pertaining to inspection of CRDM penetrations. Results of demonstrations and field inspections conducted will also be summarized. (authors)

  17. Covariances for measured activation and fission ratios data

    Methods which are routinely used in the determination of covariance matrices for both integral and differential activation and fission-ratios data acquired at the Argonne National Laboratory Fast-Neutron Generator Facility (FNG) are discussed. Special consideration is given to problems associated with the estimation of correlations between various identified sources of experimental error. Approximation methods which are commonly used to reduce the labor involved in this analysis to manageable levels are described. Results from some experiments which have been recently carried out in this laboratory are presented to illustrate these procedures. 13 refs., 1 fig., 5 tabs

  18. Integrated separation scheme for measuring a suite of fission and activation products from a fresh mixed fission and activation product sample

    Mixed fission and activation materials resulting from various nuclear processes and events contain a wide range of isotopes for analysis spanning almost the entire periodic table. This work describes the production of a complex synthetic sample containing fission products, activation products, and irradiated soil, and determines the percent chemical recovery of select isotopes through the integrated chemical separation scheme. Based on the results of this experiment, a complex synthetic sample can be prepared with low atom/fission ratios and isotopes of interest accurately and precisely measured following an integrated chemical separation method. (author)

  19. Approximation of the decay of fission and activation product mixtures

    The decay of the exposure rate from a mixture of fission and activation products is a complex function of time. The exact solution of the problem involves the solution of more than 150 tenth order Bateman equations. An approximation of this function is required for the practical solution of problems involving multiple integrations of this function. Historically this has been a power function, or a series of power functions, of time. The approach selected here has been to approximate the decay with a sum of exponential functions. This produces a continuous, single valued function, that can be made to approximate the given decay scheme to any desired degree of closeness. Further, the integral of the sum is easily calculated over any period. 3 refs

  20. Multiple-Coincidence Active Neutron Interrogation of Fissionable Materials

    Using a beam of tagged 14.1 MeV neutrons to probe for the presence of fissionable materials, we have measured n-γ-γ coincidences from depleted uranium (DU). The multiple coincidence rate is substantially above that measured from lead, tungsten, and iron. The presence of coincidences involving delayed gammas in the DU time spectra provides a signature for fissionable materials that is distinct from non-fissionable ones. In addition, the information from the tagged neutron involved in the coincidence gives the position of the fissionable material in all three dimensions. The result is an imaging probe for fissionable materials that is more compact and that produces much less radiation than other solutions

  1. Implementation of a Quality Management System in regulatory inspection activities

    The Institute for Radioprotection and Dosimetry - IRD -, of the Brazilian National Nuclear Energy Commission, CNEN, started in 2001, the implementation of a quality management system (SGQ), in the inspection, testing and calibration activities. The SGQ was an institutional guideline and is inserted in a larger system of management of the IRD started in 1999, with the adoption of the National Quality Award criteria - PNQ, within the Project for Excellence in Technological Research of Associacao Brasileira das Instituicoes de Pesquisas Tecnologicas - ABIPTI (Brazilian Association of Technological Research institutions). The proposed quality management system and adopted at the IRD was developed and implemented in accordance with the requirements of NBR ISO/IEC 17025 - General requirements for the competence of testing and calibration laboratories, and ISO/IEC 17020 - General criteria for operation of various types of bodies performing inspections. For regulatory inspection activities, the quality system was implemented on three program inspection services of radiological protection led, respectively, by clinics and hospitals that operate radiotherapy services; industries that use nuclear gauges in their control or productive processes and power reactor operators (CNAAA) - just the environmental part. It was formed a pioneering team of inspectors for standardizing the processes, procedures and starting the implementation of the system in the areas. This work describes the implementation process steps, including difficulties, learning and advantages of the adoption of a quality management system in inspection activities

  2. Treatment and solidification of high active fission product solutions

    On reprocessing spent fuel elements, > 97% of the fission products are found in the high active waste (HAW) solution. In order to avoid large amounts of sludge formation arising from phosphates produced by TBP degradation during evaporation and storage of these high level wastes, the suspended and dissolved TBP must be removed immediately from the HAW. It is proposed to separate the TBP by steam-stripping. The the HAW will be concentrated in an evaporator, the concentration factor depending on the amount of sludge formation and the heat content of the concentrate. These concentrates may be stored for short periods in stainless steel tanks. Acid concentration and waste volume may be further reduced by in-tank denitration and evaporation. For vitrification of the HAW liquid feed, ceramic melters are being developed universally. The first active plant to use a liquid feed ceramic melter is the German plant PAMELA, which is being built at Mol in Belgium, with an operational date of 1985

  3. Confidence building in and through fission and fusion activities

    The peaceful uses of atomic energy are most suitable for achieving worldwide confidence building for the following reasons. (1) In spite of the need for peaceful uses of nuclear energy, the world is facing difficulties in the public perception and acceptance of nuclear works and facilities. (2) The above difficulties are due to many factors, such as the two sides of nuclear energy peaceful and military, the possibility of a large-scale reactor accident, the lack of understanding about radiation and radioactivity, and finally, emotion and egoism. Some of these factors are unique to nuclear-energy, but in other cases of public reactions, there are many facets similar to the above factors. (3) The public concern about safety is at its highest, broadest and severest point ever, coincident with the highest life expectancy in history. Over-precaution and over-protection about certain things may sometimes spoil one's health. Nuclear energy is most definitely suffering from such a trend. As a result, a severe nuclear accident in any country results in severe damage worldwide no manner in what form the real physical effects reach other countries. (4) The huge science and technology efforts required for fission and fusion activities cannot be fully achieved by one country. Explanations of some of the above factors are given. 2 refs

  4. Role of independent inspections in verification activities

    Verification activities have an important place in the activities associated with the implementation of a quality assurance programme and concern the compliance of all work with clearly defined requirements. In the first part of this paper the author reviews these requirements, classifying them into four groups: specific requirements of the product in question, particular requirements of the organization responsible for manufacturing the product, requirements of successive customers, and regulatory requirements. The second part of the paper examines the two approaches which can be adopted to establish verification systems outside the organizational structure. The first approach is to pool or organize the monitoring resources of different bodies with common requirements (electricity producer and its principal contractors); the second consists in using an external monitoring body. The third part of the paper describes the system used in France, which is the first of the methods described above. It requires constant co-operation between the different parties involved, and these have established two associations for the purpose of applying the system - AFCEN (nuclear) and AFCEC (conventional). The advantages and disadvantages of the two possible approaches to verification of activities must be assessed within their industrial and commercial regulatory context. In France the best method has proved to be the pooling of resources. This has led to a direct and fruitful dialogue between customers and suppliers aimed at defining common requirements (Design and Construction Regulations (RCC)) and monitoring their application. (author)

  5. Active Classification: Theory and Application to Underwater Inspection

    Hollinger, Geoffrey A; Sukhatme, Gaurav S

    2011-01-01

    We discuss the problem in which an autonomous vehicle must classify an object based on multiple views. We focus on the active classification setting, where the vehicle controls which views to select to best perform the classification. The problem is formulated as an extension to Bayesian active learning, and we show connections to recent theoretical guarantees in this area. We formally analyze the benefit of acting adaptively as new information becomes available. The analysis leads to a probabilistic algorithm for determining the best views to observe based on information theoretic costs. We validate our approach in two ways, both related to underwater inspection: 3D polyhedra recognition in synthetic depth maps and ship hull inspection with imaging sonar. These tasks encompass both the planning and recognition aspects of the active classification problem. The results demonstrate that actively planning for informative views can reduce the number of necessary views by up to 80% when compared to passive methods...

  6. Proceedings of a specialists' meeting on neutron activation cross sections for fission and fusion energy applications

    These proceedings of a specialists' meeting on neutron activation cross sections for fission and fusion energy applications are divided into 4 sessions bearing on: - data needs: 4 conferences - experimental work: 11 conferences - theoretical work: 4 conferences - evaluation work: 5 conferences

  7. Active, Non-Intrusive Inspection Technologies for Homeland Defense

    James L. Jones

    2003-06-01

    Active, non-intrusive inspection or interrogation technologies have been used for 100 years - with the primary focus being radiographic imaging. During the last 50 years, various active interrogation systems have been investigated and most have revealed many unique and interesting capabilities and advantages that have already benefited the general public. Unfortunately, except for medical and specific industrial applications, these unique capabilities have not been widely adopted, largely due to the complexity of the technology, the overconfident reliance on passive detection systems to handle most challenges, and the unrealistic public concerns regarding radiation safety issues for a given active inspection deployment. The unique homeland security challenges facing the United States today are inviting more "out-of-the-box" solutions and are demanding the effective technological solutions that only active interrogation systems can provide. While revolutionary new solutions are always desired, these technology advancements are rare, and when found, usually take a long time to fully understand and implement for a given application. What's becoming more evident is that focusing on under-developed, but well-understood, active inspection technologies can provide many of the needed "out-of-the-box" solutions. This paper presents a brief historical overview of active interrogation. It identifies some of the major homeland defense challenges being confronted and the commercial and research technologies presently available and being pursued. Finally, the paper addresses the role of the Idaho National Engineering and Environmental Laboratory and its partner, the Idaho Accelerator Center at Idaho State University, in promoting and developing active inspection technologies for homeland defense.

  8. Active, Non-Intrusive Inspection Technologies for Homeland Defense

    Active, non-intrusive inspection or interrogation technologies have been used for 100 years - with the primary focus being radiographic imaging. During the last 50 years, various active interrogation systems have been investigated and most have revealed many unique and interesting capabilities and advantages that have already benefited the general public. Unfortunately, except for medical and specific industrial applications, these unique capabilities have not been widely adopted, largely due to the complexity of the technology, the overconfident reliance on passive detection systems to handle most challenges, and the unrealistic public concerns regarding radiation safety issues for a given active inspection deployment. The unique homeland security challenges facing the United States today are inviting more ''out-of-the-box'' solutions and are demanding the effective technological solutions that only active interrogation systems can provide. While revolutionary new solutions are always desired, these technology advancements are rare, and when found, usually take a long time to fully understand and implement for a given application. What's becoming more evident is that focusing on under-developed, but well-understood, active inspection technologies can provide many of the needed ''out-of-the-box'' solutions. This paper presents a brief historical overview of active interrogation. It identifies some of the major homeland defense challenges being confronted and the commercial and research technologies presently available and being pursued. Finally, the paper addresses the role of the Idaho National Engineering and Environmental Laboratory and its partner, the Idaho Accelerator Center at Idaho State University, in promoting and developing active inspection technologies for homeland defense

  9. Multistep Phosphorelay Proteins Transmit Oxidative Stress Signals to the Fission Yeast Stress-activated Protein Kinase

    Nguyen, Aaron Ngocky; Lee, Albert; Place, Warren; Shiozaki, Kazuhiro

    2000-01-01

    In response to oxidative stress, eukaryotic cells induce transcription of genes required for detoxification of oxidants. Here we present evidence that oxidative stress stimuli are transmitted by a multistep phosphorelay system to the Spc1/Sty1 stress-activated protein kinase in the fission yeast Schizosaccharomyces pombe. The fission yeast mpr1+ gene encodes a novel protein with a histidine-containing phosphotransfer domain homologous to the budding yeast Ypd1. Spc1 activation upon oxidative ...

  10. Recent Experiments on the Beta Activity of Fission Products from the Thermal-Neutron Fission of U233, U235 and Pu239

    The build-up of beta-activity of fission products from the low-energy fission of U233 and U235 has been measured as a function of the lime t after starting the irradiation of the fissionable material with thermal neutrons. By differentiating the beta-activity divided by the constant fission product rate one obtains the mean beta-decay rate β(t) per fission as a function of the time t after fission. The uranium targets were mounted within a 4π proportional counter, coincident conversion electrons and γ-rays being thereby eliminated. The background of fast neutrons and γ-rays was strongly reduced by using a neutron beam tube with a liquid nitrogen-cooled bismuth single crystal filter. The fission product rate was measured with the same counter. The measurements cover the time interval from 0.01 s to 10 h. The results are compared with other experimental data and existing theories. The total number of beta-decays per fission was found to be 5.25 ± 0.2 and 5.93 ± 0.2 for U233 and U235 respectively compared with theoretical values of 5.27 and 6.10 respectively. (author)

  11. AMP-activated protein kinase mediates mitochondrial fission in response to energy stress

    Courchet, Julien; Lewis, Tommy L.; Losón, Oliver C.; Hellberg, Kristina; Young, Nathan P.; Chen, Hsiuchen; Polleux, Franck; Chan, David C.; Shaw, Reuben J.

    2016-01-01

    Mitochondria undergo fragmentation in response to electron transport chain (ETC) poisons and mitochondrial DNA–linked disease mutations, yet how these stimuli mechanistically connect to the mitochondrial fission and fusion machinery is poorly understood. We found that the energy-sensing adenosine monophosphate (AMP)–activated protein kinase (AMPK) is genetically required for cells to undergo rapid mitochondrial fragmentation after treatment with ETC inhibitors. Moreover, direct pharmacological activation of AMPK was sufficient to rapidly promote mitochondrial fragmentation even in the absence of mitochondrial stress. A screen for substrates of AMPK identified mitochondrial fission factor (MFF), a mitochondrial outer-membrane receptor for DRP1, the cytoplasmic guanosine triphosphatase that catalyzes mitochondrial fission. Nonphosphorylatable and phosphomimetic alleles of the AMPK sites in MFF revealed that it is a key effector of AMPK-mediated mitochondrial fission. PMID:26816379

  12. Studies on separation and purification of fission 99Mo from neutron activated uranium aluminum alloy

    A new method has been developed for separation and purification of fission 99Mo from neutron activated uranium–aluminum alloy. Alkali dissolution of the irradiated target (100 mg) results in aluminum along with 99Mo and a few fission products passing into solution, while most of the fission products, activation products and uranium remain undissolved. Subsequent purification steps involve precipitation of aluminum as Al(OH)3, iodine as AgI/AgIO3 and molybdenum as Mo-α-benzoin oxime. Ruthenium is separated by volatilization as RuO4 and final purification of 99Mo was carried out using anion exchange method. The radiochemical yield of fission 99Mo was found to be >80% and the purity of the product was in conformity with the international pharmacopoeia standards. - Highlights: • 99Mo separation, purification method developed from neutron activation of 100 g U–Al alloy. • Uranium, fission, activation product decontamination by alkali dissolution of activated target. • Purification by Al(OH)3, AgI/AgIO3, Mo-α-benzoin oxime precipitation and anion exchange. • Very high decontamination factors for alpha activity obtained. • Final 99Mo product (recovery >80%) complied with international pharmacopoeia standards

  13. Tax Evasion Dynamics in Romania Reflected by Fiscal Inspection Activities

    CORINA-MARIA ENE

    2010-06-01

    Full Text Available The paper aims to provide a panoramic view of the dynamics of tax evasion in Romania, reflected in terms of fiscal inspection activities. The author used the official data published by the institutions with attributions on the line of identification and fighting against tax evasion (National Agency of Fiscal Administration and Financial Guard with the view to reflect the real situation concerning the number of inspections, quantify and sanction tax evasion for 2003-2008 periods. Although the number of fiscal inspections and the number of tax payers who have violated the rules of fiscal discipline decreased compared with 2003, the frequency of tax evasion remained. At the same time, based on the data referring to the level and dynamics of the tax dodger phenomenon appreciations have been made regarding the fiscal discipline of the Romanian tax payer and to the attitude of the qualified institutions in discovering and sanctioning the fraudulent tax evasion. In this respect, the author observed that the level of willingness of tax legislation in relation to the Romanian tax payer has not changed considerably.The level of identified tax evasion reported to real GDP increased slightly. This situation can be interpreted as a success of institutions in charge of identification and fighting of tax evasion, a result of the increase of fiscal inspection number and detection probability, but also a result of GDP growth at a rate lower than the identified tax evasion. The author has also tried to find a causality relation between the option for tax evasion and corruption. The author found that a corrupt environment facilitates the decision to evade depending on detection probability, penalty system and bribery level as discouraging factors for tax evasion. The level of identified tax evasion is smaller than the real level of entire tax evasion, an important part being impossible to determine because of corruption.

  14. Power Installations based on Activated Nuclear Reactions of Fission and Synthesis

    Grigoriev, Yuriy

    2016-01-01

    The general scheme of power installations based on nuclear reactions of fission and synthesis activated by external sources is analyzed. The external activation makes possible to support nuclear reactions at temperatures and pressures lower than needed for chain reactions, so simplifies considerably practical realization of power installations. The possibility of operation on subcritical masses allows making installations compact and safe at emergency situations. Installations are suitable for transmutation of radioactive nuclides, what solves the problem of utilization of nuclear waste products. It is proposed and considered schemes of power installations based on nuclear reactions of fission and fusion, activated by external sources, different from ADS systems. Variants of activation of nuclear reactions of fission (U-235, 238, Pu-239) and fusion (Li-6,7, B-10,11) are considered.

  15. Regulatory inspection activities related to inspection planning, plant maintenance and assessment of safety. Proceedings of an international workshop

    The NEA Committee on Nuclear Regulatory Activities (CNRA) believes that an essential factor in ensuring the safety of nuclear installations is the continuing exchange and analysis of technical information and data. To facilitate this exchange the Committee has established Working Groups and Groups of Experts in specialised topics. CNRA believes that safety inspections are a major element in the regulatory authority's efforts to ensure the safe operation of nuclear facilities. Considering the importance of these issues, the Committee has established a special Working Group on Inspection Practices (WGIP). The purpose of WGIP, is to facilitate the exchange of information and experience related to regulatory safety inspections between CNRA Member countries. This was the 3. international workshop held by the WGIP on regulatory inspection activities. The focus of this workshop was on 3 main topics; Inspection Planning, Plant Maintenance and Assessment of Safety. This document presents the proceedings from the workshop, including: workshop programme, results and conclusions, papers and presentations and the list of participants. The main purpose of the Workshop is to provide a forum of exchange of information on the regulatory inspection activities

  16. PEPIN, Methodology for Computing Concentrations, Activities, Gamma-Ray Spectra, and Residual Heat from Fission Products

    1 - Description of program or function: The concentrations, activities, gamma-ray spectra and residual heat from fission products can be calculated as a function of time for instantaneous fission or for one or more irradiation steps. 2 - Methods: Using the basic data in the libraries, the PEPIN code solves the differential equations satisfied by the fission product concentrations. Data Libraries: Independent Yields Library: 8 independent yields for 235U, 238U, 239U, 232U, 233U. Chain library: Precursor chain file for 635 nuclides. Gamma-Ray Energies Library: Average beta and gamma-ray energies in increasing order. 3 - Restrictions on the complexity of the problem: The number of nuclides must not exceed 650. The number of Gamma-Rays must not exceed 8500. The number of decay times must not exceed 59. The number of irradiation steps must not exceed 40

  17. Multiple scattering Compton camera with neutron activation for material inspection

    We designed a multiple scattering Compton camera (MSCC) based on a lanthanum bromide (LaBr3:Ce) scintillator to detect neutron-activated prompt gamma-rays for material inspection. The system parameters such as detector thickness and inter-detector distances were optimized on the basis of figure of merit (FOM). The FOM was maximized when the inter-detector distance and detector thickness were 18 cm and 1.5 cm, respectively. Under the optimized conditions, energy spectra and spatial images were obtained to identify various substances, and the results matched well with theoretical data. The probability of multiple Compton scattering was higher than that of conventional Compton scattering at high energies (~MeV), which proved the effectiveness of MSCC to detect prompt gamma-rays. Simulations with realistic conditions showed the feasibility of using the MSCC investigate of materials in field applications

  18. Measurement of the neutron activity of a 252Cf source relative to the average number of prompt neutrons emitted per fission for the spontaneous fission

    A method was developed for measuring the absolute neutron activity of a large 252Cf source. The neutron counting assembly is composed of eight BF3 counters mounted in a large tank filled with water which is used as a moderator. The detection efficiency is determined using a low activity 252Cf source. The method is based on the identification of every fission event, followed by the counting of the fission neutrons detected by the BF3 counters during a time interval equal to the maximum neutron lifetime in the moderator. The efficiency is thus obtained relative to the average number of prompt neutrons emitted per 252Cf spontaneous fission which is commonly used as a standard. The measurement accuracy is estimated to be of the order of 1%

  19. The determination of age of the fault activities of Shougou Hill, Guangzhou by thermoluminescence dating and nuclear fission track dating

    The age of the fault activities had been determined by TL dating and nuclear fission track dating. The results show that the fault of Shougou Hill had large and intense activities in mid-cenozoic era, however, intense activities still occurred in early pleistocene and mid-pleistocene. The last activity of the fault occurred 430 000 years ago. The data of TL dating are conformable with data of nuclear fission track dating

  20. Risk informed approach to the in-service inspection activities

    In the present paper, the aspects of Risk Informed In-Service Inspection (RI-ISI) are discussed. Slovenian Nuclear Safety Administration (SNSA) and its authorized organization for the ISI activities, Institute of Metals and Technologies (IMT), are actually permanently involved in the ISI processes of the nuclear power plant (NPP) Krsko. Based on the previous experience on the ISI activities, evaluation of the results and review of the existing practice in nuclear world, the activities are started to asses the piping of systems in the light of probability of failure. This is so called Risk Informed approach. By the design established criteria, standards and practice gives good fundaments for the improvements implementation. Improvements can be done on the way that the more broad knowledge about safety important components of the systems shall bee added to the basic practice. It is necessary to identify conditions of the safety important components, such as realistic stress and fatigue conditions, material properties changes due aging processes, the temperature cycling effects, existing flaws characterization in the light of the previous detection and equipment technique used, assessment of the measurement accuracy on the results etc. In addition to this deterministic approach, the principles of risk evaluation methods should be used. NPP Krsko has, as practically majority of NPP's, probabilistic risk assessment (PRA) studies for all safety important systems and components. The methods and results from these studies can be efficiently used to upgrade classical deterministic results, based on which the in-service program as a whole is usually done. In addition to the above mentioned, risk assessment and evaluation of the piping shall be done, which is not covered by the existing PRA analysis. To do this it is necessary to made risk evaluation of the piping segments, based on previous structural element probability assessment. Probabilistic risk assessment is important

  1. Assessment of failed fuel and tramp uranium based on the activity of fission products in the primary circuit

    We have proposed a model for the nuclear fuel state of the operating power reactor from the physical characteristics of nuclear fission products which have been produced by nuclear reaction between neutron and uranium-235. The model equation for nuclear fission products release has been split into size independent steps: 1) calculation of the fission products generation inside the solid nuclear fuel, 2) release from the fuel to the fuel surface in three different ways, 3) release between the fuel surface and gap, 4) release from the defective nuclear fuel to the reactor coolant, 5) mass balance in the coolant taking into account the purification rate, 6) separation of fission products sources with two parts, i.e. fuel and tramp uranium. We have solved the equation of the model, calculated the activity of fission products released from the defected fuel to coolant and put the experimental activity data of the nuclear fission products in the primary coolant to determine the number of defective fuel and amount of tramp uranium by using the computer. The measurement and analysis of nuclear fission products in the primary coolant of nuclear power reactors have been carried out at the pressurized water reactor, Korea Nuclear Unit 2, 7 and 8. We have used the iodine isotopes among the nuclides of fission products. The analysis results have been well agreed with the results of diffusion model and of kinetics model. (author). 7 refs, 2 figs, 8 tabs

  2. Application of the activation analysis using the method of retarded fission neutrons counting for the determination of some fissionable nuclides

    A system for the detection and counting of delayed neutrons which allows the analysis of some fissile and fertile nuclides, in samples of milligram size, was developed. This was applied for the analysis of natural uranium and thorium and also for determining the 235U/238U ratio in non-irradiated samples which contain uranium with different degrees of enrichment in 235U. The spectrum of activated neutrons was varied in order to discriminate the nuclides, by covering or not the sample with a material (cadmium or boron) able to absorb low energy neutrons. Determination of 235U/238U ratios, through the number of delayed neutrons, was made by drawing a calibration curve using standards ranging from 0.5% to 93% on 235U; the accuracy of the method was also examined. In a first step, conditions for a simultaneous and non-destructive analysis of uranium and thorium were developed. The interference between these two nuclides was studied, using simulated samples. Real samples were provided by Nuclemon and IAEA. For samples with uranium concentration in the range of percentages and thorium concentration of some ppm, uranium interferes in the determination of thorium through the non-destructive analytical method. For this case, a fast and quantitative chemical method was studied which allows for the separation of thorium from uranium before the determination of throrium concentration by counting the delayed fission neutrons. It was found that the results obtained by both destructive and non-destructive methods are very consistent and can be considered statistically equivalent within a confidence level of 95%. (Author)

  3. Actinides separation and long-lived fission products from the high activity effluent

    The aim of this document is to study the decontamination of a high activity effluent in minor actinides-α transmitters (241Am, 243Am, 243Cm, 245Cm, 237Np, 238Pu, 242Pu, 235U, 238U) and long-life fissions products (133Cs, 137Cs) and then the separation of Am, Cm, Np, Cs and Pu, U traces. (TEC). 16 figs., 1 tab

  4. Regulatory inspection activities on nuclear power plant sites during construction in the United Kingdom

    The work of regulatory inspection of the construction of the plant on the site is performed not only by the inspector who has been allocated to inspection duties for that site but also by the specialist staff who are involved with the safety assessment of the plant. The coordination of this work is described in the paper and examples are given of inspection activities associated with the enforcement requirements of license conditions as well as those related to the inspection of the plant itself

  5. Instrumental neutron activation analysis in geochemistry. Emphasis on spectral and uranium fission product interferences

    Full text: Since the advent of semiconductor detectors, several contributions to the INAA methodology allowed to resolve and analyse complex gamma ray spectra enhancing thus, the reliability of this analytical technique. Despite attainable performances, some difficulties due to spectral and fission product interferences remain affecting thus the reliability of analytical results. A typical case is that discussed by Landsberger et al. on the determination of Sm in the presence Gd, U and Th. In practice spectral interferences in INAA are resolved by allowing shorter-lived radionuclides to decay and counting the remaining long-lived radionuclides. It is also proceeded to the subtraction of contributions of interfering radionuclides using their interference free analytical photopeaks. Both of them are tedious and time consuming, particularly if radionuclides of interest have similar γray spectra, as is the case for 153Sm and 153Gd to which further interferences come from 239Np and 233Pa. On the other hand, the presence of fissionable products such as U and Th in geological samples, and particularly in high grade U and Th samples, enhances difficulties in the accuracy attainable by instrumental neutron activation analysis. They give rise, during irradiation, to identical (n,γ) products from isotopes of natural elements. The present contribution deals with 2 aspects of resolution of interferences in instrumental neutron activation analysis: 1. The application of a multicomponent method for the resolution of spectral interferences in gamma spectrometry using simultaneous equations method. Assume m elements are to be determined by INAA whose (n,γ) products interfere at their n analytical γ-rays. An overall analytical response can be assumed to consist of several additive individual responses from m interfering radionuclides. The mathematical terms can be expressed by means of the following equation: Pn=k+Σain Aiεi Pn = Photopeak area at the specific interfering n

  6. Early ERK1/2 activation promotes DRP1-dependent mitochondrial fission necessary for cell reprogramming.

    Prieto, Javier; León, Marian; Ponsoda, Xavier; Sendra, Ramón; Bort, Roque; Ferrer-Lorente, Raquel; Raya, Angel; López-García, Carlos; Torres, Josema

    2016-01-01

    During the process of reprogramming to induced pluripotent stem (iPS) cells, somatic cells switch from oxidative to glycolytic metabolism, a transition associated with profound mitochondrial reorganization. Neither the importance of mitochondrial remodelling for cell reprogramming, nor the molecular mechanisms controlling this process are well understood. Here, we show that an early wave of mitochondrial fragmentation occurs upon expression of reprogramming factors. Reprogramming-induced mitochondrial fission is associated with a minor decrease in mitochondrial mass but not with mitophagy. The pro-fission factor Drp1 is phosphorylated early in reprogramming, and its knockdown and inhibition impairs both mitochondrial fragmentation and generation of iPS cell colonies. Drp1 phosphorylation depends on Erk activation in early reprogramming, which occurs, at least in part, due to downregulation of the MAP kinase phosphatase Dusp6. Taken together, our data indicate that mitochondrial fission controlled by an Erk-Drp1 axis constitutes an early and necessary step in the reprogramming process to pluripotency. PMID:27030341

  7. Determination of uranium fission products interference factors in neutron activation analysis

    Neutron activation analysis is a method used in the determination of several elements in different kinds of matrices. However, when the sample contains high U levels the problem of 235U fission interference occurs. A way to solve this problem is to perform the correction using the interference factor due to U fission for the radionuclides used on elemental analysis. In this study was determined the interference factor due to U fission for the radioisotopes 141Ce, 143Ce, 140La, 99Mo, 147Nd, 153Sm and 95Zr in the research nuclear reactor IEA-R1 on IPEN-CNEN/SP. These interference factors were determined experimentally, by irradiation of synthetic standards for 8 hours in a selected position in the reactor, and theoretically, determining the epithermal to neutron fluxes ratio in the same position where synthetic standards were irradiated and using reported nuclear parameters on the literature. The obtained interference factors were compared with values reported by other works. To evaluate the reliability of these factors they were applied in the analysis of studied elements in the certified reference materials NIST 8704 Buffalo River Sediment, IRMM BCR- 667 Estuarine Sediment e IAEA-SL-1 Lake Sediment. (author)

  8. SSNTD study of the probable influence of alpha activity on the mass distribution of 252Cf fission fragments

    The SSNTD has come a long way in its application for the study of nuclear phenomena. Spontaneous fission of transuranic elements is one such phenomena wherein use of SSNTD offers easy registration of the signature of the fission fragments. The object of the present study is to explore whether any one of the track parameters such as the diameter can be used to estimate the atomic mass ratios of the spontaneous fission fragments. The spontaneous fission data from 252Cf recorded almost at the end of one and four half-life periods for alpha decay are analysed, taking a plot of the number of tracks versus the track diameter. From these plots it is seen that initially, when significant alpha activity of 252Cf persists, the fission fragments appear to cluster into two predominant groups as indicated by two peaks. The ratio of the diameters at these peak positions appear to be related to the ratio of average mass numbers of the light and heavy groups of fission fragments. However, absence of two peaks for similar plots at the end of about four half-life periods for alpha decay suggests that presumably the presence of alphas influence the mass distribution of the fission fragments

  9. Improving of methods and organization of the inspection activity of The Bank of Russia

    Fedulov Vladislav Igorevich

    2011-10-01

    Full Text Available The article presents information about the main causes of bank failures at present, that has been taken to find some lacks of modern organization of the Bank of Russia inspection activity. In order to eliminate the revealed lacks we supplied some methods for increasing the effectiveness of the unscheduled narrowly focused thematic inspections that are held to update opinions of supervisor about the risks and to obtain quickly reliable information about specific areas of the bank. Such an approach to organization of inspection activities is more in line with the concept of risk-focused supervision.

  10. Neutron activation analysis (NAA), radioisotope production via neutron activation (PNA) and fission product gas-jet (GJA)

    Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    Three different non-diffractive applications of neutrons are outlined, neutron activation analysis, production of radionuclides, mostly for medical applications, and production of short-lived fission nuclides with a so-called gas-jet. It is shown that all three devices may be incorporated into one single insert at SINQ due to their different requests with respect to thermal neutron flux. Some applications of these three facilities are summarized. (author) 3 figs., 1 tab., 8 refs.

  11. IAEA activity on partitioning and transmutation of actinides and fission products

    In 1990, the IAEA received a request from Member States to review the status of research and development on partitioning and transmutation of actinides and fission products. In response to this request the Advisory Group Meeting (AG) was held in the fall of 1991. AG advised the Agency to play an active role in coordinating international activities in this area. A series of meetings that followed identified considerable interest among many Member States and international organizations in the P and T options as a potential complement to the reference concepts of the back-end of nuclear fuel cycle. Inherent difficulties for the Agency to actively explore this programme were identified including non-proliferation concerns from some Member States about partitioning technology and possible duplication of effort in other international organizations, especially OECD/NEA. But, there remain fundamental questions to be addressed on the objectives of and motivations for P and T and it is clear that some common international understanding would be necessary. In order to contribute to the solution of this problem, and considering the existence of programmes being implemented by OECD/NEA, the Agency has initiated a new CRP entitled 'Safety, environmental and non-proliferation aspects of partitioning and transmutation of actinides and fission products' (1994-1998). This presentation will explain about this Agency's new CRP and how the Agency's work is co-ordinated with other international activities. (author)

  12. Air activity variations as estimation of inhalation dose for the gases fission products

    This article presents that dissolved impurities are responsible for water activity and the release of fission gases Radon and Thoron into the reactor hall atmosphere. In normal operation of the reactor at 400 kilowatts, wide fluctuations in airborne activity (gross beta) between 15,000-200,000 dpm/m3 have been noticed. The aerosol concentration, reactor hall temperature, relative humidity and ventilation rate are the factors influencing the levels of airborne activity in the reactor hall atmosphere. These parameters are discussed in relation to the observed air activities. The diffusion coefficient of the decay products and the unattached fraction of the decay products are necessary parameters for the estimation of lung dose. These have been measured. Internal exposure results from the deposition of radioactive material within the body through inhalation, ingestion and absorption. A recent study has indicated that inhalation is the main route of entry, and nearly 75% of the cases of internal contamination are attributable to inhalation. It has been demonstrated that the inert fission gases like Radon and Thoron do not contribute significantly to the dose due to inhalation to the working personnel in reactors, but their decay products which are particulate β emitters, contribute significant inhalation dose

  13. Development of calculation code of fission products specific activity in primary coolant

    Based on an assumption of that there is a design basis fuel defect level from reactor startup, calculation method of fission products specific activities in primary coolant is studied. Time-dependent nuclide activities in defect fuel are calculated by ORIGEN code, and nuclide releases from the defect fuel are considered. After processed by interface codes, data are used by PCFPA code which is used to calculate nuclide activities in the coolant. PCFPA solves differential equations by unit of decay chain, and totally considers decay's contribution to nuclide activities, and considers different system design between secondary and third generation plants such as AP1000. The method could provide the maximum of specific activity during plant operation and their results are consistent with data in AP1000 DCD(Rev.16). The method could be applicable to shielding design in secondary and third generation plants such as AP1000. (authors)

  14. Neutron capture cross-section of fission products in the European activation file EAF-3

    This paper contains a description of the work performed to extend and revise the neutron capture data in the European Activation File (EAF-3) with emphasis on nuclides in the fission-product mass range. The starter was the EAF-1 data file from 1989. The present version, EAF/NG-3, contains (n,γ) excitation functions for all nuclides (729 targets) with half-lives exceeding 1/2 day in the mass range from H-1 to Cm-248. The data file is equipped with a preliminary uncertainty file, that will be improved in the near future. (author). 19 refs.; 5 figs.; 3 tabs

  15. Golgi membrane fission requires the CtBP1-S/BARS-induced activation of lysophosphatidic acid acyltransferase δ.

    Pagliuso, Alessandro; Valente, Carmen; Giordano, Lucia Laura; Filograna, Angela; Li, Guiling; Circolo, Diego; Turacchio, Gabriele; Marzullo, Vincenzo Manuel; Mandrich, Luigi; Zhukovsky, Mikhail A; Formiggini, Fabio; Polishchuk, Roman S; Corda, Daniela; Luini, Alberto

    2016-01-01

    Membrane fission is an essential cellular process by which continuous membranes split into separate parts. We have previously identified CtBP1-S/BARS (BARS) as a key component of a protein complex that is required for fission of several endomembranes, including basolateral post-Golgi transport carriers. Assembly of this complex occurs at the Golgi apparatus, where BARS binds to the phosphoinositide kinase PI4KIIIβ through a 14-3-3γ dimer, as well as to ARF and the PKD and PAK kinases. We now report that, when incorporated into this complex, BARS binds to and activates a trans-Golgi lysophosphatidic acid (LPA) acyltransferase type δ (LPAATδ) that converts LPA into phosphatidic acid (PA); and that this reaction is essential for fission of the carriers. LPA and PA have unique biophysical properties, and their interconversion might facilitate the fission process either directly or indirectly (via recruitment of proteins that bind to PA, including BARS itself). PMID:27401954

  16. Forecasting the Quantity and Activity of Fission Products in France in Future Years in the Light of Atomic Energy Development

    With the aid of Wigner and Way's formula it is possible to predict theoretically the activity of the complex mixture of fission products originating in a reactor. Account is taken in the study of prospective nuclear power production in France up to 1975. It is assumed that the uranium stays in the reactor for periods of three and of six months. It is also possible to determine the activity of a given fission product and to calculate its decay time. The substance selected was strontium for an activation period of three months. Each group of curves shows total activity at any moment and the activity of particular fission products over a given period. (author)

  17. Inspection planning

    Slovenian Nuclear Safety Administration (SNSA) division of nuclear and radiological safety inspection has developed systematic approach to their inspections. To be efficient in their efforts regarding regular and other types of inspections, in past years, the inspection plan has been developed. It is yearly based and organized on a such systematic way, that all areas of nuclear safety important activities of the licensee are covered. The inspection plan assures appropriate preparation for conducting the inspections, allows the overview of the progress regarding the areas to be covered during the year. Depending on the licensee activities and nature of facility (nuclear power plant, research reactor, radioactive waste storage, others), the plan has different levels of intensity of inspections and also their frequency. One of the basic approaches of the plan is to cover all nuclear and radiological important activities on such way, that all regulatory requests are fulfilled. In addition, the inspection plan is a good tool to improve inspection effectiveness based on previous experience and allows to have the oversight of the current status of fulfillment of planned inspections. Future improvement of the plan is necessary in the light of newest achievements on this field in the nuclear world, that means, new types of inspections are planned and will be incorporated into plan in next year.(author)

  18. Steam generator inspection activities at the EPRI NDE center

    This report describes a multi-tasked project under the joint sponsorship of EPRI and EPRI Steam Generator Owners Group II. The overall project objectives include the evaluation and transfer of steam generator tube inspection NDE technology. Including the Center's first offering of the eddy current data analysis course on steam generator tubing in July-August 1985, the data analysis program has been offered six times to a total of 31 students. The students are from seven utilities, four vendors, and the NDE Center. To maximize the effectiveness of the course, a students-to-instructor ratio no greater than seven is typically maintained for each class. The program is fully compatible with the existing hardware/software being used in the industry and can be given in either analog or digital format, depending on the student's selection of eddy current analysis equipment

  19. Using Electronic Neutron Generators in Active Interrogation to Detect Shielded Fissionable Material

    Experiments have been performed at Idaho National Laboratory to study methodology and instrumentation for performing neutron active interrogation die-away analyses for the purpose of detecting shielded fissionable material. Here we report initial work using a portable DT electronic neutron generator with a He-3 fast neutron detector to detect shielded fissionable material including >2 kg quantities of enriched uranium and plutonium. Measurements have been taken of bare material as well as of material hidden within a large plywood cube. Results from this work have demonstrated the efficacy of the die-away neutron measurement technique for quickly detecting the presence of special nuclear material hidden within plywood shields by analyzing the time dependent neutron signals in-between neutron generator pulses. Using a DT electronic neutron generator operating at 300 Hz with a yield of approximately 0.36 x 10**8 neutrons per second, 2.2 kg of enriched uranium hidden within a 0.60 m x 0.60 m x 0.70 m volume of plywood was positively detected with a measurement signal 2-sigma above the passive background within 1 second. Similarly, for a 500 second measurement period a lower detection limit of approaching the gram level could be expected with the same simple set-up

  20. Construction appraisal team inspection results on welding and nondestructive examination activities

    This report summarizes data and findings on deficiencies and discrepancies in welding and nondestructive examination (NDE) activities identified by the US Nuclear Regulatory Commission Construction Appraisal Team (CAT) during its inspection of 11 plants. The CAT reviewed selected welds and NDE packages in its inspection of the following plant areas: piping and pipe supports and/or restraints; modification and installation of reactor internals; electrical installations and electrical supports; instrumentation tubing and supports; heating, ventilation, and air conditioning (HVAC) systems and supports; fabrication and erection of structural steel; fabrication of refueling cavity and spent fuel pool liner; containment liner and containment penetrations; and fire protection systems. The CAT inspected both structural welds and pressure-retaining welds and reviewed welder qualification test records and welding procedure documents for code compliance. The NDE activities that were evaluated included visual examination, magnetic particle examination, liquid penetrant examination, ultrasonic examination, and radiographic examination of welds. 4 refs., 14 figs., 15 tabs

  1. Observation of new spontaneous fission activities from elements 100 to 105

    Somerville, L.P.

    1982-03-01

    Several new Spontaneous Fission (SF) activities have been found. No definite identification could be made for any of the new SF activities; however, half-lives and possible assignments to element-104 isotopes consistent with several cross bombardments include /sup 257/Rf(3.8 s, 14% SF), /sup 258/Rf(13 ms), /sup 259/Rf(approx. 3 s, 8% SF), /sup 260/Rf(approx. 20 ms), and /sup 262/Rf(approx. 50 ms). The 80-ms SF activity claimed by the Dubna group for the discovery of element 104 (/sup 260/104) was not observed. A difficulty exists in the interpretation that /sup 260/Rf is a approx. 20-ms SF activity: in order to be correct, for example, the SF activities with half-lives between 14 and 24 ms produced in the reactions 109- to 119-MeV /sup 18/O + /sup 248/Cm, 88- to 100-MeV /sup 15/N + /sup 249/Bk, and 96-MeV /sup 18/O + /sup 249/Cf must be other nuclides due to their large production cross sections, or the cross sections for production of /sup 260/Rf must be enhanced by unknown mechanisms. Based on calculated total production cross sections a possible approx. 1% electron-capture branch in /sup 258/Lr(4.5 s) to the SF emitter /sup 258/No(1.2 ms) and an upper limit of 0.05% for SF branching in /sup 254/No(55 s) were determined. Other measured half-lives from unknown nuclides produced in respective reactions include approx. 1.6 s (/sup 18/O + /sup 248/CM), indications of a approx. 47-s SF activity (75-MeV /sup 12/C + /sup 249/Cf), and two or more SF activities with 3 s less than or equal to T/sub 1/2/ less than or equal to 60 s (/sup 18/O + /sup 249/Bk). The most exciting conclusion of this work is that if the tentative assignments to even-even element 104 isotopes are correct, there would be a sudden change in the SF half-life systematics at element 104 which has been predicted theoretically and attributed to the disappearance of the second hump of the double-humped fission barrier.

  2. Remote systems for inspection and repair of a highly active dissolver

    An integrated remote handling system has been built to carry out inspections inside a nuclear fuel dissolver vessel. Tooling is provided to effect repairs to the dissolver if required. The system incorporates a novel manipulator, closed circuit television (CCTV), endoscopes, ultrasonic inspection probes, remote machining and remote tungsten inert gas (TIG) welding packages. An advanced computer control system is provided to allow the operator to monitor, interlock and control the complex equipment. Technique research is complete and non-active test results to date are reported. (Author)

  3. Status of fission yield measurements

    Fission yield measurement and yield compilation activities in the major laboratories of the world are reviewed. In addition to a general review of the effort of each laboratory, a brief summary of yield measurement activities by fissioning nuclide is presented. A new fast reactor fission yield measurement program being conducted in the US is described

  4. Inspection of surveillance activities and administrative leave policy at Bonneville Power Administration, Portland, Oregon

    1994-04-01

    The authors conducted an inspection of surveillance activities and administrative leave policy at the Bonneville Power Administration, Portland, Oregon. The purpose of their inspection was to determine if a covert video surveillance operation conducted at Bonneville Power Administration was consistent with Department of Energy policies and procedures and other applicable regulations and procedures, and to determine if administrative leave policies and procedures used at Bonneville Power Administration in a specific instance were consistent with Department of Energy requirements and the Code of Federal Regulations. This inspection focused on a specific incident that occurred in 1989 on the 5th floor of the BPA Headquarters Building located in Portland, Oregon. The incident involved the soiling of an employee`s personal property with what appeared to be urine.

  5. Ternary Fission

    The fission process in which heavy nuclei fragment into three large charged panicles, in place of the usual two, has been studied in the case of thermal-neutron-induced fission of U235 and the spontaneous fission of Cf252. Solid-state detectors, a fast triple coincidence system and a three-coincident-parameter analyser were used to measure the three fission fragment energies parallel with the detection of each ternary fission event. Experimental evidence is presented supporting the existence of ternary fission by specifically excluding recoil phenomena and accidental events as contributing to the observed three-fold coincidence events. Mass-energy-angular correlations of ternary fission have been determined and are summarized as follows: The total kinetic energy release in ternary fission appears to be slightly higher (by approximately 10 MeV) than that for binary fission. In the case of the spontaneous ternary fission of Cf252, the frequency of occurrence is observed to be greater than 2.2 x 10-6 ternary fission events per binary fission event. Tripartition of Cf252 results preferentially in division into two medium mass particle (one of which has a mass number near 56) and one larger mass. In the case of thermal-neutron-induced fission of U235, the frequency of occurrence is observed to be greater than 1.2 x 10-6 ternary fission events per binary fission event. Ternary fission of U236: results in the formation of one light fragment (near mass 36) and two large fragments or, as in the case of Cf252, two medium fragments and one large one. These results indicate that axially asymmetric distortion modes are possible in the pre-scission configurations of the fissioning nucleus. A description is given of experiments designed to radiochemically detect the light fragment resulting from ternary fission. (author)

  6. Progress in fission product nuclear data

    This is the tenth issue of a report series on Fission Product Data, which informs us about all the activities in this field, which are planned, ongoing, or have recently been completed. The types of activities included are measurements, compilations and evaluations of: fission product yields (neutron induced and spontaneous fission), neutron reaction cross sections of fission products, data related to the radioactive decay of fission products, delayed neutron data of fission products, lumped fission product data (decay heat, absorption, etc.). There is also a section with recent references relative to fission product nuclear data

  7. Establish Techniques for Small Scale Indigenous Molybdenum-99 Production Using LEU Fission or Neutron Activation [Country report: Pakistan

    Low enriched uranium foil (19.99% 235U) may be used as target material for the production of fission molybdenum-99 (99Mo) in the Pakistan Research Reactor-1 (PARR-1). LEU foil annular targets or LEU foil plate targets can be irradiated in PARR-1 for the production of >100 Ci of 99Mo at the end of irradiation. Neutronic and thermal hydraulic analysis for the fission 99Mo production at PARR-1 has been performed. Power levels in the foil targets and their corresponding irradiation time durations were initially determined by neutronic analysis to have the required neutron fluence. Finally the thermal hydraulic analysis has been carried out for the proposed designs of the target holders using LEU foil for fission 99Mo production at PARR-1. Data shows that LEU foil targets can be safely irradiated in PARR-1 for production of desired amount of fission 99Mo. Although Pakistan is producing 99Mo by the irradiation of HEU uranium alloy plates with aluminium clad targets in PARR-1 to meet the demands of 99Mo/99mTc generators in the country, it intends to use LEU aluminide targets in coming years. In this perspective, R&D work on fabrication of LEU target for 99Mo using natural uranium has been initiated at PINSTECH. Preliminary results of LEU target plate manufactured indigenously at PINSTECH show quite good separation of 99Mo from target matrix activity. (author)

  8. Method for measuring prompt fission neutron energy spectrum by means of threshold activation detectors

    Prompt fission neutron energy spectrum as a function of energies of neutron inducing fission has been calculated on the basis of the Madland-Nix(MN) model. The resultant spectra have been weighted to excitation functions of 27Al(n,α), 32S(n,p) and 115In(n,n) threshold reactions in order to get the average cross sections and then spectral indices which are defined as the average cross section ratio for two selective threshold reactions among the above three. It is appeared that spectral indices together with the neutron spectra are varying with energies of neutron inducing fission. This may indicate that the prompt fission neutron energy spectrum can be determined by measuring experimentally the spectral index.(Author)

  9. IAEA CRP on Fission Yield Data and activity of WG in Japanese Nuclear Data Committee

    The outline of the coordinate research program on fission yield data organized by International Atomic Energy Agency and the working group on the subject newly organized in Japanese Nuclear Data Committee are presented. (author)

  10. Nuclear fission

    The nuclear fission process is pedagogically reviewed from a macroscopic-microscopic point of view. The Droplet model is considered. The fission dynamics is discussed utilizing path integrals and semiclassical methods. (L.C.)

  11. Radioactive fission and activation products: Transport from soil to plant under swedish field conditions

    The uptake of four activation products: 57 Co, 54 Mn, 65 Zn and 63 Ni, and two fission products: 90 Sr and 137 Cs by different crops was studied in a long term field experiment. Some of the soils used were sampled in the vicinity of nuclear power plants, while the others represented the most frequent types of agricultural soils occurring in Sweden. Data on the uptake by clover, timothy and wheat during the period 1976-84 were used for the calculation of soil-plant transfer factors of these nuclides. The temporal distribution of the transfer factors and the variations exhibited by the different nuclides were examined, as well as the differences between crops. The increased uptake at the early stage of the experiment observed in clover and to some extent in wheat is discussed. The soil characteristics that most influenced the uptake are the pH and the soil content of calcium, potassium and clay. The nuclide fractionation in soil was evaluated and regression analyses were employed to quantify the dependence of uptake on soil parameters. The nuclide fractions delivered to consumption through grain foods was calculated, highlighting the temporal variation of this contribution. 112 refs., 23 figs., 39 tabs

  12. New light sources and sensors for active optical 3D inspection

    Osten, Wolfgang; Jueptner, Werner P. O.

    1999-11-01

    The implementation of active processing strategies in optical 3D-inspection needs the availability of flexible hardware solutions. The system components illumination and sensor/detector are actively involved in the processing chain by a feedback loop that is controlled by the evaluation process. Therefore this article deals with new light sources and sensor which appeared recently on the market and can be applied successfully for the implementation of active processing principles. Some applications where such new components are used to implement an active measurement strategy are presented.

  13. Measurements of the neutron-spectra on the nuclear plants by means of the activation and fission detectors

    Here are presented the results of the neutron spectra determinations on the nuclear plants HPRR(USA), SILEN (FRANCE), and VIPER (GREAT BRITAIN) by means of a method developed in the Institute for Nuclear Sciences BORIS KIDRIC, Vinca based on the measurements of the induced activities in the activation detectors, created number of fissions in the fission detectors as well as on the measurements of the specific activity Na-24 in a phantom of BOMAB type. The measurements of the neutron spectra by means of the activation and fission detectors is particularly convenient on the nuclear plants operating on an impulse rate, where exist neutron fields of relatively high intensities. The forms of the neutron spectra on these plants measured by the method developed in the Institute BORIS KIDRIC for the needs of the accidental dosimetry are used to determine the mean values of the conversion factors fluens - absorbed dose of the neutrons for the energy interval 1 keV - 14 MeV. The results are compared with the values obtained by the other authors and in most cases the departures were within 10%. (author)

  14. Inspection of surveillance equipment and activities at DOE Field Office, Richland

    1991-09-30

    The purpose of this inspection was to review surveillance activities by the Department of Energy's (DOE) Field Office, Richland (RL) and contractor employees at the RL Hanford site for efficiency and economy and compliance with laws and regulations. The scope included surveillance activities, procedures, training, types of surveillance equipment, and management controls over the equipment and activities. We also looked at Departmental policies and procedures regarding the equipment and activities. Allegations of illegal surveillance that came to our attention during the course of this inspection were referred to the Department of Justice. As part of our review, inspectors were on-site at RL from February 11, 1991, through March 1, 1991. Follow-up trips to RL were also made in April, May, and June 1991. We also conducted interviews at Albuquerque, Savannah River, and Germantown of former RL employees and RL contractors who were on travel. Officials from DOE's Office of General Counsel (OGC), Office of Security Affairs, and Office of Safeguards and Security (S S) were also interviewed regarding the Department's purchase and possession of wiretapping and eavesdropping devices. We obtained 75 signed sworn statements from 55 individuals during the course of the inspection. 1 fig., 1 tab.

  15. Large-scale transcriptome data reveals transcriptional activity of fission yeast LTR retrotransposons

    Willerslev Eske

    2010-03-01

    Full Text Available Abstract Background Retrotransposons are transposable elements that proliferate within eukaryotic genomes through a process involving reverse transcription. The numbers of retrotransposons within genomes and differences between closely related species may yield insight into the evolutionary history of the elements. Less is known about the ongoing dynamics of retrotransposons, as analysis of genome sequences will only reveal insertions of retrotransposons that are fixed - or near fixation - in the population or strain from which genetic material has been extracted for sequencing. One pre-requisite for retrotransposition is transcription of the elements. Given their intrinsic sequence redundancy, transcriptome-level analyses of transposable elements are scarce. We have used recently published transcriptome data from the fission yeast Schizosaccharomyces pombe to assess the ability to detect and describe transcriptional activity from Long Terminal Repeat (LTR retrotransposons. LTR retrotransposons are normally flanked by two LTR sequences. However, the majority of LTR sequences in S. pombe exist as solitary LTRs, i.e. as single terminal repeat sequences not flanking a retrotransposon. Transcriptional activity was analysed for both full-length LTR retrotransposons and solitary LTRs. Results Two independent sets of transcriptome data reveal the presence of full-length, polyadenylated transcripts from LTR retrotransposons in S. pombe during growth phase in rich medium. The redundancy of retrotransposon sequences makes it difficult to assess which elements are transcriptionally active, but data strongly indicates that only a subset of the LTR retrotransposons contribute significantly to the detected transcription. A considerable level of reverse strand transcription is also detected. Equal levels of transcriptional activity are observed from both strands of solitary LTR sequences. Transcriptome data collected during meiosis suggests that transcription

  16. Nuclear fission

    V.M. STRUTINSKY's semi-classical method is the most precise to determine the energy of the different states along the fission way. The double-humped fission barrier explains fission isomerism. V.M. STRUTINSKY's barrier explains the ''intermediate structure'' observed in the cross section under the threshold; it provides also the observed effect of ''vibrational resonances'' with an interpretation. Taking an asymmetry parameter in consideration, a triple-humped fission barrier seems to be essential now for the light actinides. There is still a microscopic fission barrier to be explained

  17. Compilation of Data on Radionuclide Data for Specific Activity, Specific Heat and Fission Product Yields

    Gibbs, A.; Thomason, R.S.

    2000-09-05

    This compilation was undertaken to update the data used in calculation of curie and heat loadings of waste containers in the Solid Waste Management Facility. The data has broad general use and has been cross-checked extensively in order to be of use in the Materials Accountability arena. The fission product cross-sections have been included because they are of use in the Environmental Remediation and Waste Management areas where radionuclides which are not readily detectable need to be calculated from the relative fission yields and material dispersion data.

  18. Compilation of Data on Radionuclide Data for Specific Activity, Specific Heat and Fission Product Yields

    This compilation was undertaken to update the data used in calculation of curie and heat loadings of waste containers in the Solid Waste Management Facility. The data has broad general use and has been cross-checked extensively in order to be of use in the Materials Accountability arena. The fission product cross-sections have been included because they are of use in the Environmental Remediation and Waste Management areas where radionuclides which are not readily detectable need to be calculated from the relative fission yields and material dispersion data

  19. Determination of fission and activation products in nearly fresh fuel elements by self-calibration

    Gamma spectra at several axial positions of the BR02 fuel element X133 have been measured and the concentration of 137Cs has been determined directly. On basis of this determination and some assumptions of the irradiation history, the concentrations of other fission products, relevant for the cold reprocessing process, have been calculated. On the basis of ORIGEN-type calculations the concentration of some relevant transuranics has been estimated. Both the concentrations of the fission products and of the transuranics appeared to be below the threshold values. Therefore it could be decided that cold reprocessing was feasible for all old BR02 fuel elements. (author)

  20. Conserved and Diverged Functions of the Calcineurin-Activated Prz1 Transcription Factor in Fission Yeast

    Chatfield-Reed, Kate; Vachon, Lianne; Kwon, Eun-Joo Gina; Chua, Gordon

    2016-01-01

    Gene regulation in response to intracellular calcium is mediated by the calcineurin-activated transcription factor Prz1 in the fission yeast Schizosaccharomyces pombe. Genome-wide studies of the Crz1 and CrzA fungal orthologs have uncovered numerous target genes involved in conserved and species-specific cellular processes. In contrast, very few target genes of Prz1 have been published. This article identifies an extensive list of genes using transcriptome and ChIP-chip analyses under inducing conditions of Prz1, including CaCl2 and tunicamycin treatment, as well as a ∆pmr1 genetic background. We identified 165 upregulated putative target genes of Prz1 in which the majority contained a calcium-dependent response element in their promoters, similar to that of the Saccharomyces cerevisiae ortholog Crz1. These genes were functionally enriched for Crz1-conserved processes such as cell-wall biosynthesis. Overexpression of prz1+ increased resistance to the cell-wall degradation enzyme zymolyase, likely from upregulation of the O-mannosyltransferase encoding gene omh1+. Loss of omh1+ abrogates this phenotype. We uncovered a novel inhibitory role in flocculation for Prz1. Loss of prz1+ resulted in constitutive flocculation and upregulation of genes encoding the flocculins Gsf2 and Pfl3, as well as the transcription factor Cbf12. The constitutive flocculation of the ∆prz1 strain was abrogated by the loss of gsf2+ or cbf12+. This study reveals that Prz1 functions as a positive and negative transcriptional regulator of genes involved in cell-wall biosynthesis and flocculation, respectively. Moreover, comparison of target genes between Crz1/CrzA and Prz1 indicate some conservation in DNA-binding specificity, but also substantial rewiring of the calcineurin-mediated transcriptional regulatory network. PMID:26896331

  1. Conserved and Diverged Functions of the Calcineurin-Activated Prz1 Transcription Factor in Fission Yeast.

    Chatfield-Reed, Kate; Vachon, Lianne; Kwon, Eun-Joo Gina; Chua, Gordon

    2016-04-01

    Gene regulation in response to intracellular calcium is mediated by the calcineurin-activated transcription factor Prz1 in the fission yeastSchizosaccharomyces pombe Genome-wide studies of theCrz1and CrzA fungal orthologs have uncovered numerous target genes involved in conserved and species-specific cellular processes. In contrast, very few target genes of Prz1 have been published. This article identifies an extensive list of genes using transcriptome and ChIP-chip analyses under inducing conditions of Prz1, including CaCl2and tunicamycin treatment, as well as a∆pmr1genetic background. We identified 165 upregulated putative target genes of Prz1 in which the majority contained a calcium-dependent response element in their promoters, similar to that of theSaccharomyces cerevisiaeorthologCrz1 These genes were functionally enriched forCrz1-conserved processes such as cell-wall biosynthesis. Overexpression ofprz1(+)increased resistance to the cell-wall degradation enzyme zymolyase, likely from upregulation of theO-mannosyltransferase encoding geneomh1(+) Loss ofomh1(+)abrogates this phenotype. We uncovered a novel inhibitory role in flocculation for Prz1. Loss ofprz1(+)resulted in constitutive flocculation and upregulation of genes encoding the flocculins Gsf2 and Pfl3, as well as the transcription factor Cbf12. The constitutive flocculation of the∆prz1strain was abrogated by the loss ofgsf2(+)orcbf12(+) This study reveals that Prz1 functions as a positive and negative transcriptional regulator of genes involved in cell-wall biosynthesis and flocculation, respectively. Moreover, comparison of target genes betweenCrz1/CrzA and Prz1 indicate some conservation in DNA-binding specificity, but also substantial rewiring of the calcineurin-mediated transcriptional regulatory network. PMID:26896331

  2. Properties and detection of ionizing radiation resulting from instantaneous fission and fission product mixture

    The different types of ionizing radiation accompanying fission and mixtures of fission products, their activity, the determination of the age of fission products and the biological hazard of radiation caused by instantaneous fission are described. The possibility is described of detection, and of the dosimetry of ionizing radiation resulting from instantaneous fission and emitted by a mixture of fission products, the determination of the dose of neutron radiation, surface contamination, internal contamination and the contamination of water and foods. (J.P.)

  3. Experience from the Inspection of Licensees' Outage Activities, Including Fire Protection Programmes, Event Response Inspections, and the Impact of the Fukushima Daiichi NPP Accident on Inspection Programmes. Workshop Proceedings, Chattanooga, Tennessee, United States, 7-10 April 2014

    The main purpose of the workshop was to provide a forum of exchange of information on the regulatory inspection activities. Participants had the opportunity to meet with their counterparts from other countries and organisations to discuss current and future issues on the selected topics. They developed conclusions regarding these issues and hopefully, identified methods to help improve their own inspection programmes. The NEA Committee on Nuclear Regulatory Activities (CNRA) believes that an essential factor in ensuring the safety of nuclear installations is the continuing exchange and analysis of technical information and data. To facilitate this exchange the Committee has established working groups and groups of experts in specialised topics. The Working Group on Inspection Practices (WGIP) was formed in 1990 with the mandate '..to concentrate on the conduct of inspections and how the effectiveness of inspections could be evaluated..'. The WGIP facilitates the exchange of information and experience related to regulatory safety inspections between CNRA member countries. These proceedings cover the 12. International Workshop held by WGIP on regulatory inspection activities. This workshop, which is the twelfth in a series, along with many other activities performed by the Working Group, is directed towards this goal. The consensus from participants at previous workshops, noted that the value of meeting with people from other inspection organisations was one of the most important achievements. The focus of this workshop was on experience gained from regulatory inspection activities in three areas: - Inspection of Outage Activities Including Fire Protection Programmes. - Event Response Inspections. - The Impact of Inspection Programmes of the Fukushima Daiichi Nuclear Power Plant (NPP) Accident. The main objectives of the WGIP workshops are to enable inspectors to meet with inspectors from other organisations, to exchange information regarding regulatory inspection

  4. The fission yeast git5 gene encodes a Gbeta subunit required for glucose-triggered adenylate cyclase activation.

    Landry, S; Pettit, M T; Apolinario, E; Hoffman, C. S.

    2000-01-01

    Fission yeast adenylate cyclase is activated by the gpa2 Galpha subunit of a heterotrimeric guanine-nucleotide binding protein (G protein). We show that the git5 gene, also required for this activation, encodes a Gbeta subunit. In contrast to another study, we show that git5 is not a negative regulator of the gpa1 Galpha involved in the pheromone response pathway. While 43% identical to mammalian Gbeta's, the git5 protein lacks the amino-terminal coiled-coil found in other Gbeta subunits, yet...

  5. Spontaneous fission

    Recent experimental results for spontaneous fission half-lives and fission fragment mass and kinetic-energy distributions and other properties of the fragments are reviewed and compared with recent theoretical models. The experimental data lend support to the existence of the predicted deformed shells near Z = 108 and N = 162. Prospects for extending detailed studies of spontaneous fission properties to elements beyond hahnium (element 105) are considered. (orig.)

  6. Near Real-Time Nondestructive Active Inspection Technologies Utilizing Delayed γ-Rays and Neutrons for Advanced Safeguards

    In this two year project, the research team investigated how delayed γ-rays from short-lived fission fragments detected in the short interval between irradiating pulses can be exploited for advanced safeguards technologies. This program contained experimental and modeling efforts. The experimental effort measured the emitted spectra, time histories and correlations of the delayed γ-rays from aqueous solutions and solid targets containing fissionable isotopes. The modeling effort first developed and benchmarked a hybrid Monte Carlo simulation technique based on these experiments. The benchmarked simulations were then extended to other safeguards scenarios, allowing comparisons to other advanced safeguards technologies and to investigate combined techniques. Ultimately, the experiments demonstrated the possible utility of actively induced delayed γ-ray spectroscopy for fissionable material assay.

  7. Near Real-Time Nondestructive Active Inspection Technologies Utilizing Delayed γ-Rays and Neutrons for Advanced Safeguards

    Hunt, Alan [Idaho State Univ., Pocatello, ID (United States). Idaho Accelerator Center, Dept. of Physics; Reedy, E. T.E. [Idaho State Univ., Pocatello, ID (United States). Dept. of Phyics, Idaho Accelerator Center; Mozin, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tobin, S. J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Nuclear Nonproliferation

    2015-02-12

    In this two year project, the research team investigated how delayed γ-rays from short-lived fission fragments detected in the short interval between irradiating pulses can be exploited for advanced safeguards technologies. This program contained experimental and modeling efforts. The experimental effort measured the emitted spectra, time histories and correlations of the delayed γ-rays from aqueous solutions and solid targets containing fissionable isotopes. The modeling effort first developed and benchmarked a hybrid Monte Carlo simulation technique based on these experiments. The benchmarked simulations were then extended to other safeguards scenarios, allowing comparisons to other advanced safeguards technologies and to investigate combined techniques. Ultimately, the experiments demonstrated the possible utility of actively induced delayed γ-ray spectroscopy for fissionable material assay.

  8. Plasmid construction using recombination activity in the fission yeast Schizosaccharomyces pombe.

    Ayako Chino

    Full Text Available BACKGROUND: Construction of plasmids is crucial in modern genetic manipulation. As of now, the common method for constructing plasmids is to digest specific DNA sequences with restriction enzymes and to ligate the resulting DNA fragments with DNA ligase. Another potent method to construct plasmids, known as gap-repair cloning (GRC, is commonly used in the budding yeast Saccharomyces cerevisiae. GRC makes use of the homologous recombination activity that occurs within the yeast cells. Due to its flexible design and efficiency, GRC has been frequently used for constructing plasmids with complex structures as well as genome-wide plasmid collections. Although there have been reports indicating GRC feasibility in the fission yeast Schizosaccharomyces pombe, this species is not commonly used for GRC as systematic studies of reporting GRC efficiency in S. pombe have not been performed till date. METHODOLOGY/PRINCIPAL FINDINGS: We investigated GRC efficiency in S. pombe in this study. We first showed that GRC was feasible in S. pombe by constructing a plasmid that contained the LEU2 auxotrophic marker gene in vivo and showed sufficient efficiency with short homology sequences (>25 bp. No preference was shown for the sequence length from the cut site in the vector plasmid. We next showed that plasmids could be constructed in a proper way using 3 DNA fragments with 70% efficiency without any specific selections being made. The GRC efficiency with 3 DNA fragments was dramatically increased >95% in lig4Delta mutant cell, where non-homologous end joining is deficient. Following this approach, we successfully constructed plasmid vectors with leu1+, ade6+, his5+, and lys1+ markers with the low-copy stable plasmid pDblet as a backbone by applying GRC in S. pombe. CONCLUSIONS/SIGNIFICANCE: We concluded that GRC was sufficiently feasible in S. pombe for genome-wide gene functional analysis as well as for regular plasmid construction. Plasmids with different

  9. The use of NPAR [Nuclear Plant Aging Research] results in plant inspection activities

    The US NRC's Nuclear Plant Aging Research (NPAR) Program is a hardware oriented research program which has produced a large data base of equipment and system operating, maintenance, and testing information. Equipment and systems which have a propensity for age related degradation are identified, and methods for detecting and mitigating aging effects have been evaluated. As plants age, it becomes increasingly important that NRC inspectors be cognizant of plant aging phenomena. This paper describes the NPAR information which can enhance inspection activities, and provides a mechanism for making pertinent research available to the inspectors. 7 refs., 2 figs

  10. The use of NPAR (Nuclear Plant Aging Research) results in plant inspection activities

    Gunther, W.; Taylor, J.

    1989-01-01

    The US NRC's Nuclear Plant Aging Research (NPAR) Program is a hardware oriented research program which has produced a large data base of equipment and system operating, maintenance, and testing information. Equipment and systems which have a propensity for age related degradation are identified, and methods for detecting and mitigating aging effects have been evaluated. As plants age, it becomes increasingly important that NRC inspectors be cognizant of plant aging phenomena. This paper describes the NPAR information which can enhance inspection activities, and provides a mechanism for making pertinent research available to the inspectors. 7 refs., 2 figs.

  11. Isotopic compositions of inventory designations, open-quote mixed fission product close-quote and open-quote mixed activation product close-quote

    The Area G Performance Assessment requires that the entire inventory be specified in terms of specific nuclide activities. The inventory data base has historically allowed some less specific inventory designations including Mixed Fission Products (MFP), Mixed Activation Products (MAP), several Material Type (MT) designations and others. This report describes the assignment of specific nuclide activities from the listed activity amounts in two of the inventory data base categories, MFP and MAP. The MFP nuclide assignment is based on standard fission product yield data and normalized to total activity at two years post-fission. The MAP assignment is based on site-specific analyses conducted by the major generator of the activation products at Los Alamos, the LAMPE

  12. Spontaneous Fission

    Segre, Emilio

    1950-11-22

    The first attempt to discover spontaneous fission in uranium was made by [Willard] Libby, who, however, failed to detect it on account of the smallness of effect. In 1940, [K. A.] Petrzhak and [G. N.] Flerov, using more sensitive methods, discovered spontaneous fission in uranium and gave some rough estimates of the spontaneous fission decay constant of this substance. Subsequently, extensive experimental work on the subject has been performed by several investigators and will be quoted in the various sections. [N.] Bohr and [A.] Wheeler have given a theory of the effect based on the usual ideas of penetration of potential barriers. On this project spontaneous fission has been studied for the past several years in an effort to obtain a complete picture of the phenomenon. For this purpose the spontaneous fission decay constants {lambda} have been measured for separated isotopes of the heavy elements wherever possible. Moreover, the number {nu} of neutrons emitted per fission has been measured wherever feasible, and other characteristics of the spontaneous fission process have been studied. This report summarizes the spontaneous fission work done at Los Alamos up to January 1, 1945. A chronological record of the work is contained in the Los Alamos monthly reports.

  13. Large-scale transcriptome data reveals transcriptional activity of fission yeast LTR retrotransposons

    Mourier, Tobias; Willerslev, Eske

    2010-01-01

    ABSTRACT: BACKGROUND: Retrotransposons are transposable elements that proliferate within eukaryotic genomes through a process involving reverse transcription. The numbers of retrotransposons within genomes and differences between closely related species may yield insight into the evolutionary......-requisite for retrotransposition is transcription of the elements. Given their intrinsic sequence redundancy, transcriptome-level analyses of transposable elements are scarce. We have used recently published transcriptome data from the fission yeast Schizosaccharomyces pombe to assess the ability to detect and describe...

  14. Fission gas activities in the fuel-to-clad gap calculated with the code FUROM

    The fuel behaviour code FUROM (FUel ROd Model) has been in use and under improvement for several years at the Hungarian Academy of Sciences KFKI Atomic Energy Research Institute. Several new features are added to it each year. In the present paper an extended fission gas release model is introduced. This model is suitable for the calculation of the release of not only stable but also radioactive isotopes. Code calculations are compared to international results. (authors)

  15. Delayed-neutron activities produced in fission: Mass range 122--146

    Delayed-neutron emission from mass separated heavy fission products has been studied using a sensitive neutron counter. Twelve new delayed-neutron precursors have been found, namely 122Ag, 123Ag, 127In, 128Cd (or 128In/sub m/), 128In, 129In (two isomers), 130In, 131In, 132In, 133Sn, and 136Sb. The half-life determination for 11 other precursors has been improved

  16. Separation of transuranium elements and fission products from medium activity aqueous liquid wastes

    In the course of work performed between January 1981 and June 1985 on the separation of TRU elements and fission products three liquid alpha containing waste streams were treated: - medium level waste solutions, - waste solutions from the acid digestion of burnable alpha containing solid residues, - waste solutions from mixed oxide fuel element fabrication. The method of separation was initially developed and optimized with simulating substances. Subesequently it was tested with real waste solutions

  17. Amount and activity of fission products which will be obtainable in France in the immediate future taking into account the development of atomic energy

    By using the Wigner and Way formula, the activity of the complex mixture of fission products produced in a pile may be estimated theoretically in advance. This study was carried out on the basis of forecasts, in the case of France for the production of electricity of atomic origin up to the year 1975. The uranium was assumed to be in the pile during periods of three months and six months. It is also possible to find the activity of a particular fission product and to give its decay rate. The element chosen is strontium for a three months' activation period. Each set of curves gives at any moment the total activity accumulated, and the characteristic activity of the fission products corresponding to a given half-life. (author)

  18. Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

    This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure

  19. Monitoring and inspection techniques for long term storage of higher activity waste packages

    In 2009, following recent changes in United Kingdom (UK) Government Policy, the Nuclear Decommissioning Authority (NDA) identified a knowledge gap in the area of long term interim storage of waste packages. A cross-industry Integrated Project Team (IPT) for Interim Storage was created with responsibility for delivering Industry Guidance on the storage of packaged Higher Activity Waste (HAW) for the current UK civil decommissioning and clean-up programmes. This included a remit to direct research and development projects via the NDA's Direct Research Portfolio (DRP) to fill the knowledge gap. The IPT for Interim Storage published Industry Guidance in 2012 which established a method to define generic package performance criteria and made recommendations on monitoring and inspection. The package performance method consists of the following steps; identification of the package safety function, identification of evolutionary processes that may affect safety function performance, determination of measurable indicators of these evolutionary processes and calibration of the indicators into package performance zones. This article provides an overview of three projects funded by the NDA's DRP that the UK National Nuclear Laboratory (NNL) have completed to address monitoring and inspection needs of waste packages in interim storage. (orig.)

  20. Apatite fission track analysis on tectonic activities and paleotopography in southern Altai region, Xinjiang, China

    This work engages apatite fission track evidences on thermotectonic history, rock uplift rate, denudation extent southeastern Altai region. Fission track ages of 14 samples range from (59.4±5.8) Ma to (109.7±8.1) Ma and the length is between (12.0±2.5) μm and (13.7±1.5) μm. Thermal modeling reveals that the samples have a three-stage of uplift-cooling history. The first stage is in an overall initial uplift before 108 Ma, the second stage from 108 Ma to 28 Ma experiences a slow cooling phase, and the last stage through a rapid-cooling process since 28 Ma with a cooling rate 1.25 1.61 ℃/Ma and denudation amount 1.17-1.50 km, the fast exhumation period in the area. The sample ages could be divided into 4 age groups, reflecting multiple tectonic events with different uplift rates. The paleotopography altitude changes from 3895 m to 821 m, 2250 m to 762 m etc., and the amplitude of changes reaches to 3300-1400 m since 90 Ma. The phenomenon of Alpine turning to valley and valley uplifting is visible in the studied area, indicating various stages of paleotopography. Based on inversion of ancient landforms and equilibrium correction, the equilibrium rebound would play an important role in the rock uplift during the Altai post-orogenic period. (authors)

  1. Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System

    Bromberger, B; Brandis, M; Dangendorf, V; Goldberg, M B; Kaufmann, F; Mor, I; Nolte, R; Schmiedel, M; Tittelmeier, K; Vartsky, D; Wershofen, H

    2012-01-01

    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and gamma radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. T...

  2. Contribution to the study of nuclear fission

    The author proposes an overview of his research activity during the past fifteen years and more particularly that dealing with nuclear fission. The first part reports works on nucleus physics at the scission via the investigation of ternary fission (experimental procedure, influence of fission modes, influence of resonance spin, influence of excitation energy of the fissioning nucleus, emission probabilities, energy spectra of ternary alphas and tritons, emission mechanism). The second part reports measurements and assessments of neutron-induced fission cross sections. The third part reports the investigation of some properties of fission products (efficiencies, branching ratios of the main delayed neutron precursors)

  3. NRC inspections of licensee activities to improve the performance of motor-operated valves

    The NRC regulations require that components important to the safe operation of a nuclear power plant be treated in a manner that provides assurance of their proper performance. Despite these regulatory requirements, operating experience and research programs have raised concerns regarding the performance of motor-operated valves (MOVs) in nuclear power plants. In June 1990, the staff issued NUREG-1352, Action Plans for Motor-Operated Valves and Check Valves, which contains planned actions to organize the activities aimed at resolving the concerns about MOV performance. A significant task of the MOV action plan is the staff's review of the implementation of Generic Letter (GL) 89-10 (June 28, 1989), 'Safety-Related Motor-Operated Valve Testing and Surveillance,' and its supplements, by nuclear power plant licensees. The NRC staff has issued several supplements to GL 89-10 to provide additional guidance for use by licensees in responding to the generic letter. The NRC staff has conducted initial inspections of the GL 89-10 programs at most licensee facilities. This paper outlines some of the more significant findings of those inspections. For example, licensees who have begun differential pressure and flow testing have found some MOVs to require more thrust to operate than predicted by the standard industry equation with typical valve factors assumed in the past. The NRC staff has found weaknesses in licensee procedures for conducting the differential pressure and flow tests, the acceptance criteria for the tests in evaluating the capability of the MOV to perform its safety function under design basis conditions, and feedback of the test results into the methodology used by the licensee in predicting the thrust requirements for other MOVs. Some licensees have not made adequate progress toward resolving the MOV issue for their facilities within the recommended schedule of GL 89-10

  4. Ternary fission

    M Balasubramaniam; K R Vijayaraghavan; C Karthikraj

    2015-09-01

    We present the ternary fission of 252Cf and 236U within a three-cluster model as well as in a level density approach. The competition between collinear and equatorial geometry is studied by calculating the ternary fragmentation potential as a function of the angle between the lines joining the stationary middle fragment and the two end fragments. The obtained results for the 16O accompanying ternary fission indicate that collinear configuration is preferred to equatorial configuration. Further, for all the possible third fragments, the potential energy surface (PES) is calculated corresponding to an arrangement in which the heaviest and the lightest fragments are considered at the end in a collinear configuration. The PES reveals several possible ternary modes including true ternary modes where the three fragments are of similar size. The complete mass distributions of Si and Ca which accompanied ternary fission of 236U is studied within a level density picture. The obtained results favour several possible ternary combinations.

  5. Progress in fission product nuclear data

    This is the 12th issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the IAEA. The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The type of activities included are: measurements, compilations and evaluations of fission product yields (neutron induced and spontaneous fission), neutron reaction cross sections of fission products, data related to the radioactive decay of fission products, delayed neutron data of fission products and lumped fission product data (decay heat, absorption etc.). The first part of the report consists of unaltered original contributions which the authors have sent to IAEA/NDS. The second part contains recent references relative to fission product nuclear data, which were not covered by the contributions submitted, and selected papers from conferences

  6. Comparison of fission signatures from β− delayed γ-ray and neutron emissions

    The delayed γ-ray and neutron fission signals utilized in active inspection techniques were measured simultaneously in order to directly compare their detection sensitivities. Fissionable and non-fissionable targets were irradiated by a 15-Hz pulsed bremsstrahlung beam operating at endpoint energies from 7 to 22 MeV. The fissionable mass detection limits for both these signals decreased approximately three orders of magnitude as the irradiation energy was increased with the delayed γ-ray limits 4.3–8.2 times smaller. The signals from the non-fissionable targets were consistent with the natural passive backgrounds for irradiation energies up to 16 MeV. At higher bremsstrahlung energies, there was a target independent active background in the delayed γ-ray signal that accounted for 35% of the gross yield. In addition, these higher irradiation energies resulted in products from 9Be(γ,p)8Li and 18O(γ,p)17N reactions interfering with the delayed γ-ray and neutron fission signals, respectively

  7. Regulation of the fission product activity in the primary coolant and assessment of defective fuel rod characteristics in steady-state WWER-type reactor operation

    Regulation of the maximum limiting levels of fuel cladding failure and normalizing of the fission product activity in the primary coolant of WWER-type reactors for steady-state reactor operation is considered. It is shown that for the advanced nuclear power plants with WWER-type reactors the maximum permissible level of fuel rod failure and fission product activity in the primary coolant must be determined taking into account the actual level of the fuel rod reliability, possible failures of other reactor equipment (steam generator tubes) and efficiency of the primary and secondary coolant purification systems. The computer code TIMS developed in RRC 'Kurchatov Institute' for the assessment of the number of failed fuel rods and defect characteristics by comparing measured and calculated values of fission product activities in primary coolant is described. The important feature of the code is the increase of reliability of assessment by taking into account the actual errors of fission product activity measurements and possible contamination of primary circuit. (author)

  8. Benchmarking Nuclear Fission Theory

    G. F. Bertsch(INT, Seattle, USA); Loveland, W.; Nazarewicz, W.; Talou, P.

    2015-01-01

    We suggest a small set of fission observables to be used as test cases for validation of theoretical calculations. The purpose is to provide common data to facilitate the comparison of different fission theories and models. The proposed observables are chosen from fission barriers, spontaneous fission lifetimes, fission yield characteristics, and fission isomer excitation energies.

  9. Fission Spectrum

    Bloch, F.; Staub, H.

    1943-08-18

    Measurements of the spectrum of the fission neutrons of 25 are described, in which the energy of the neutrons is determined from the ionization produced by individual hydrogen recoils. The slow neutrons producing fission are obtained by slowing down the fast neutrons from the Be-D reaction of the Stanford cyclotron. In order to distinguish between fission neutrons and the remaining fast cyclotron neutrons both the cyclotron current and the pusle amplifier are modulated. A hollow neutron container, in which slow neutrons have a lifetime of about 2 milliseconds, avoids the use of large distances. This method results in much higher intensities than the usual modulation arrangement. The results show a continuous distribution of neutrons with a rather wide maximum at about 0.8 MV falling off to half of its maximum value at 2.0 MV. The total number of netrons is determined by comparison with the number of fission fragments. The result seems to indicate that only about 30% of the neutrons have energies below .8 MV. Various tests are described which were performed in order to rule out modification of the spectrum by inelastic scattering. Decl. May 4, 1951

  10. Singlet Fission

    Smith, M. B.; Michl, Josef

    2010-01-01

    Roč. 110, č. 11 (2010), s. 6891-6936. ISSN 0009-2665 Grant ostatní: Department of Energy(US) DE-FG36-08GO18017 Institutional research plan: CEZ:AV0Z40550506 Keywords : solar energy conversion * photovoltaics * singlet fission Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 33.033, year: 2010

  11. Ideological Fission

    Christiansen, Steen Ledet

    materialisation of an ideological fission which attempts to excise certain ideological constructions, yet paradoxically casting them in a form that is recognizable and familiar. The monstrous metonomy which is used shows us glimpses of a horrid being, intended to vilify the attack on New York City. However, it is...

  12. Mobile neutron/gamma waste assay system for characterization of waste containing transuranics, uranium, and fission/activation products

    A new integrated neutron/gamma assay system has been built for measuring 55-gallon drums at Pacific Northwest Laboratory. The system is unique because it allows simultaneous measurement of neutrons and gamma-rays. This technique also allows measurement of transuranics (TRU), uranium, and fission/activation products, screening for shielded Special Nuclear Material prior to disposal, and critically determinations prior to transportation. The new system is positioned on a platform with rollers and installed inside a trailer or large van to allow transportation of the system to the waste site instead of movement of the drums to the scanner. The ability to move the system to the waste drums is particularly useful for drum retrieval programs common to all DOE sites and minimizes transportation problems on the site. For longer campaigns, the system can be moved into a facility. The mobile system consists of two separate subsystems: a passive Segmented Gamma Scanner (SGS) and a open-quotes clam-shellclose quotes passive neutron counter. The SGS with high purity germanium detector and 75Se transmission source simultaneously scan the height of the drum allowing identification of unshieled open-quotes hot spotsclose quotes in the drum or segments where the matrix is too dense for the transmission source to penetrate. Dense segments can flag shielding material that could be used to hide plutonium or uranium during the gamma analysis. The passive nuetron counter with JSR-12N Neutron Coincidence Analyzer measures the coincident neutrons from the spontaneous fission of even isotopes of plutonium. Because high-density shielding produces minimal absorption of neutrons, compared to gamma rays, the passive neutron portion of the system can detect shielded SNM. Measurements to evaluate the performance of the system are still underway at Pacific Northwest Laboratory

  13. A model for predicting fission product activities in reactor coolant: application of model for estimating I-129 levels in radioactive waste

    A general model was developed to estimate the activities of fission products in reactor coolant and hence to predict a value for the I-129/Cs-137 scaling factor. The latter can be applied along with measured Cs-137 activities to estimate I-129 levels in reactor waste. The model accounts for fission product release from both defective fuel rods and uranium contamination present on in-core reactor surfaces. For simplicity, only the key release mechanisms were modeled. A mass balance, considering the two fuel source terms and a loss term due to coolant cleanup was solved to estimate fission product activity in the primary heat transport system coolant. Steady state assumptions were made to solve for the activity of short-lived fission products. Solutions for long-lived fission products are time-dependent. Data for short-lived radioiodines I-131, I-132, I-133, I-134 and I-135 were analysed to estimate model parameters for I-129. The estimated parameter values were then used to determine I-129 coolant activities. Because of the chemical affinity between iodine and cesium, estimates of Cs-137 coolant concentrations were also based on parameter values similar to those for the radioiodines. This assumption was tested by comparing measured and predicted Cs-137 coolant concentrations. Application of the derived model to Douglas Point and Darlington Nuclear Generating Station plant data yielded estimates for I-129/I-131 and I-129/Cs-137, which are consistent with values reported for pressurised water reactors (PWRs) and boiling water reactors (BWRs). The estimated magnitude for the I-129/Cs-137 ratio was10-8 - 10-7. (author)

  14. A MODEL FOR PREDICTING FISSION PRODUCT ACTIVITIES IN REACTOR COOLANT: APPLICATION OF MODEL FOR ESTIMATING I-129 LEVELS IN RADIOACTIVE WASTE

    A general model was developed to estimate the activities of fission products in reactor coolant and hence to predict a value for the I-129/Cs-137 scaling factor; the latter can be applied along with measured Cs-137 activities to estimate I-129 levels in reactor waste. The model accounts for fission product release from both defective fuel rods and uranium contamination present on in-core reactor surfaces. For simplicity, only the key release mechanisms were modeled. A mass balance, considering the two fuel source terms and a loss term due to coolant cleanup was solved to estimate fission product activity in the primary heat transport system coolant. Steady state assumptions were made to solve for the activity of shortlived fission products. Solutions for long-lived fission products are time-dependent. Data for short-lived radioiodines I-131, I-132, I-133, I-134 and I-135 were analyzed to estimate model parameters for I-129. The estimated parameter values were then used to determine I-1 29 coolant activities. Because of the chemical affinity between iodine and cesium, estimates of Cs-137 coolant concentrations were also based on parameter values similar to those for the radioiodines; this assumption was tested by comparing measured and predicted Cs-137 coolant concentrations. Application of the derived model to Douglas Point and Darlington Nuclear Generating Station plant data yielded estimates for I-129/I-131 and I-129/Cs-137 which are consistent with values reported for pressurized water reactors (PWRs) and boiling water reactors (BWRs). The estimated magnitude for the I-129/Cs-137 ratio was 10-8 - 10-7

  15. A MODEL FOR PREDICTING FISSION PRODUCT ACTIVITIES IN REACTOR COOLANT: APPLICATION OF MODEL FOR ESTIMATING I-129 LEVELS IN RADIOACTIVE WASTE

    Lewis, B.J.; Husain, A.

    2003-02-27

    A general model was developed to estimate the activities of fission products in reactor coolant and hence to predict a value for the I-129/Cs-137 scaling factor; the latter can be applied along with measured Cs-137 activities to estimate I-129 levels in reactor waste. The model accounts for fission product release from both defective fuel rods and uranium contamination present on in-core reactor surfaces. For simplicity, only the key release mechanisms were modeled. A mass balance, considering the two fuel source terms and a loss term due to coolant cleanup was solved to estimate fission product activity in the primary heat transport system coolant. Steady state assumptions were made to solve for the activity of shortlived fission products. Solutions for long-lived fission products are time-dependent. Data for short-lived radioiodines I-131, I-132, I-133, I-134 and I-135 were analyzed to estimate model parameters for I-129. The estimated parameter values were then used to determine I-1 29 coolant activities. Because of the chemical affinity between iodine and cesium, estimates of Cs-137 coolant concentrations were also based on parameter values similar to those for the radioiodines; this assumption was tested by comparing measured and predicted Cs-137 coolant concentrations. Application of the derived model to Douglas Point and Darlington Nuclear Generating Station plant data yielded estimates for I-129/I-131 and I-129/Cs-137 which are consistent with values reported for pressurized water reactors (PWRs) and boiling water reactors (BWRs). The estimated magnitude for the I-129/Cs-137 ratio was 10-8 - 10-7.

  16. NECTAR: Radiography and tomography station using fission neutrons

    Bücherl, Thomas; Söllradl, Stefan

    2015-01-01

    NECTAR, operated by the Technische Universität München, is a versatile facility for the non-destructive inspection of various objects by means of fission neutron radiography and tomography, respectively.

  17. Constitutive Activation of the Fission Yeast Pheromone-Responsive Pathway Induces Ectopic Meiosis and Reveals Ste11 as a Mitogen-Activated Protein Kinase Target

    Kjærulff, Søren; Lautrup-Larsen, I.; Truelsen, S.;

    2005-01-01

    In the fission yeast Schizosaccharomyces pombe, meiosis normally takes place in diploid zygotes resulting from conjugation of haploid cells. In the present study, we report that the expression of a constitutively activated version of the pheromone-responsive mitogen-activated protein kinase kinase...... kinase (MAP3K) Byr2 can induce ectopic meiosis directly in haploid cells. We find that the Ste11 transcription factor becomes constitutively expressed in these cells and that the expression of pheromone-responsive genes no longer depends on nitrogen starvation. Epistasis analysis revealed that these...... conditions bypassed the requirement for the meiotic activator Mei3. Since Mei3 is normally needed for inactivation of the meiosis-repressing protein kinase Pat1, this finding suggests that the strong Byr2 signal causes inactivation of Pat1 by an alternative mechanism. Consistent with this possibility, we...

  18. Fission product yields from 22 MeV neutron-induced fission of 235U

    The chain yields of 28 product nuclides were determined for the fission of 235U induced by 22 MeV neutrons for the first time. Absolute fission rate was monitored with a double-fission chamber. Fission product activities were measured by HPGe γ-ray spectrometry. Time of flight technique was used to measure the neutron spectrum in order to estimate fission events induced by break-up neutrons and scattering neutrons. A mass distribution curve was obtained and the dependence of fission yield on neutron energy is discussed

  19. Fission product yields from 19.1 MeV neutron induced fission of 238U

    36 chain yields were determined for the fission of 238U induced by 19.1 MeV neutrons for the first time. Absolute fission rate was monitored with a double-fission chamber. Fission product activities were measured by HPGe γ-ray spectrometry. Threshold detector method was used to measure the neutron spectrum in order to estimate the fission events induced by break-up neutrons and scattering neutrons. A mass distribution curve was obtained and the dependence of fission yield on neutron energy was discussed

  20. Measurement of fission cross sections

    A review is presented on the recent progress in the experiment of fission cross section measurement, including recent activity in Japan being carried out under the project of nuclear data measurement. (author)

  1. Fission meter

    Rowland, Mark S.; Snyderman, Neal J.

    2012-04-10

    A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly into information that a first responder can use to discriminate materials. The system comprises counting neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source.

  2. Progress in fission product nuclear data

    This is the eleventh issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The types of activities being included in this report are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission); Neutron reaction cross sections of fission products; Data related to the radioactive decay of fission products; Delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The main part of this report consists of unaltered original contributions which the authors have sent to IAEA/NDS

  3. Current activities and challenges of the European network for inspection and qualification (ENIQ)

    Martin, Oliver [European Commission, Joint Research Centre (JRC), Petten (Netherlands). Institute for Energy and Transport (IET); Martin, Etienne [EDF, St Denis (France). Direction Production Ingenierie; Booler, Russ [AMEC Clean Energy Europe, Warrington (United Kingdom); Zetterwall, Tommy [Swedish Qualification Centre, Taeby (Sweden); Walker, Tony [Rolls-Royce Submarines, Derby (United Kingdom)

    2014-10-15

    This article describes the development of the European Network for Inspection and Qualification (ENIQ) since the previous presentation of the network in the 2011 April/May edition of this journal, covering mainly the new technical challenges facing the network and resulting projects as well as the establishment of the new Task Group for Inspection Qualification Bodies. ENIQ is a utility-driven network dealing with the reliability and effectiveness of non-destructive testing (NDT) for nuclear power plants (NPP). ENIQ is recognised as one of the main contributors to today's global qualification codes and guidelines for in-service inspection (ISI) and has published nearly 50 documents. Among them are the 'European Methodology for Qualification of Non-Destructive Testing', the first qualification methodology based on technical justifications, the 'European Framework Document for Risk-Informed In-Service Inspection (RI-ISI)', and various recommend practices. In addition ENIQ has carried out two pilot studies and a number of surveys. In 2012, ENIQ joined the European based R and D association on Gen II and III reactors, NUGENIA, making ENIQ its 8{sup th} technical area. Following the entry into NUGENIA, ENIQ members have updated the ENIQ roadmap and included a number of new technical challenges facing its members in the near future. Also ENIQ established a third task group in 2013, the Task Group for Inspection Qualification Bodies (TGIQB), which should serve as an exchange forum for inspection qualification bodies. ENIQ is currently preparing or performing new projects and studies to tackle these challenges and new recommended practices and reports are likely to evolve from these projects, which will enable ENIQ to maintain its role as one of the main contributors to today's global qualification codes and guidelines for ISI.

  4. Measurement of fission product activity in the Peach Bottom Reactor primary coolant loop

    The distribution of gamma-emitting radionuclides deposited in the primary circuit of the Peach Bottom High-Temperature Gas-Cooled Reactor (HTGR) at end-of-life has been determined by in situ gamma scanning. The work was part of the Peach Bottom End-of-Life Program and was performed by the IRT Corporation under subcontract to General Atomic Company. The measurements were made to support a design method verification exercise. The specific activity on the ducts was measured by external scans at local points with a Ge(Li) detector and by internal scans with a travelling intrinsic germanium detector (after destructive removal of trepan samples); the activity on the steam generator tube bundle was determined by traversing selected tubes with travelling CdTe detectors from the water side. Calibration measurements on mockups allowed reduction of the spectra to specific activity

  5. Historical evolution of nuclear energy systems development and related activities in JAERI. Fission, fusion, accelerator utilization

    Tone, Tatsuzo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    Overview of the historical evolution of nuclear energy systems development and related activities in JAERI is given in the report. This report reviews the research and development for light water reactor, fast breeder reactor, high temperature gas reactor, fusion reactor and utilization of accelerator-based neutron source. (author)

  6. Historical evolution of nuclear energy systems development and related activities in JAERI. Fission, fusion, accelerator utilization

    Overview of the historical evolution of nuclear energy systems development and related activities in JAERI is given in the report. This report reviews the research and development for light water reactor, fast breeder reactor, high temperature gas reactor, fusion reactor and utilization of accelerator-based neutron source. (author)

  7. Experience from the Inspection of Licensees' Outage Activities, Including Fire Protection Programmes, Event Response Inspections, and the Impact of the Fukushima Daiichi NPP Accident on Inspection Programmes. Workshop Proceedings, Chattanooga, Tennessee, United States, 7-10 April 2014 - Appendix: Compilation of Survey Responses

    This appendix provides the complete compilation of responses received to the questionnaire issued in conjunction with the workshop announcements. The responses are provided as received, with changes made only to the formatting. The OECD Nuclear Energy Agency (NEA) Committee on Nuclear Regulatory Activities (CNRA) Working Group on Inspection Practices (WGIP) sponsored the 12. International Workshop on Nuclear Regulatory Inspection Activities. The workshop was hosted by the U.S. NRC, in Chattanooga, Tennessee, United States of America on 7 -10 April 2014. The three workshop topics that were addressed were as follows: - Inspection of Outage Activities Including Fire Protection Programmes. - Event Response Inspections. - The Impact of Inspection Programmes of the Fukushima Daiichi NPP Accident. Each of the respondents was given the following instructions in relation to their response: - Only one response per country is required. If more than one person from your country is participating, please co-ordinate the responses accordingly. - Please provide responses on separate sheet and clearly identify the questionnaire part and topic. For preparation of the workshop, participants are invited to supply their national inspection approaches used in inspection of events and incidents according to the surveys. Actual issues that were discussed during the workshop were generated by the topic leaders based on the responses submitted by participants with their registration forms. This formats helps to ensure that issues considered most important by the workshop participants are covered during the group discussions. (authors)

  8. 78 FR 48180 - Consolidation of Officer in Charge, Marine Inspection For Outer Continental Shelf Activities...

    2013-08-07

    ... Act notice regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR...) to oversee marine inspections for all Mobile Offshore Drilling Units and Floating Outer Continental... Coast in Mobile, Alabama; New Orleans, Louisiana; Morgan City, Louisiana; Port Arthur, Texas;...

  9. Recent developments for an active UF6 gas target for photon-induced fission experiments

    Freudenberger M.

    2013-12-01

    Full Text Available Recent developments for an active uranium-hexafluoride-loaded gas target as well as results on the detector gas properties are presented. The gas of choice is a mixture of argon with small amounts of UF6. This contribution presents the experimental setup and focusses on the electron drift velocity with increasing UF6 content. A time-dependent decrease in electron drift velocity is observed in our setup.

  10. Recent developments for an active UF6 gas target for photon-induced fission experiments

    Freudenberger M.; Eckardt C.; Enders J.; Göök A.; von Neumann-Cosel P.; Oberstedt A.; Oberstedt S.

    2013-01-01

    Recent developments for an active uranium-hexafluoride-loaded gas target as well as results on the detector gas properties are presented. The gas of choice is a mixture of argon with small amounts of UF6. This contribution presents the experimental setup and focusses on the electron drift velocity with increasing UF6 content. A time-dependent decrease in electron drift velocity is observed in our setup.

  11. Apatite fission-track data from upper Cretaceous formations in the Yuan'an Graben (China): Constraints on the timing of synsedimentary fault activity

    Apatite fission-track signatures of upper Cretaceous Formations in the Yuan'an Graben are made to constraint on the timing of the Yuan'an and Tongchenghe synsedimentary fault activity. The apatite fission-track ages range from 102.0 ± 14.6 to 84.1 ± 3.7 Ma with P(χ2) >0.05; the mean confined track lengths of 14.18 ± 0.09 and 14.16 ± 0.08 μm with mean Dpar values of 2.25 ± 0.02 and 2.26 ± 0.03 μm, respectively. These data are interpreted as dating their source-area exhumation, recording the exhumation and cooling of the footwall during major normal faulting. The results indicate that the timing of the Yuan'an and Tongchenghe synsedimentary fault activity occurred at 117–82 Ma and the intensive movement at 100–82 Ma; the onset time of extension in Jianghan Basin is ca. 117 Ma, which is related to the lithospheric extension associated with the subduction of the Pacific Plate beneath the Asian Plate. - Highlights: ► Apatite fission-track dating is used to constraint on the timing of fault activity. ► The onset time of extension in Jianghan Basin is ca. 117 Ma. ► Combination of AFT and ESR to determine a Graben evolution

  12. Monitoring of Scrap Metal - Experience with Radioactive Sources and Activation/Fission Products

    Conclusions: RPMs at entrance gates of scrap yards, steelworks, foundries etc.; • generally capable of detecting dangerous activity levels - preventing radioactive sources from entering the facility; • help avoiding harm to workers and general public; • help averting financial disaster for the facility caused by melting a large radiation source. • RPMs: • are reliable; • can detect sufficiently low activities of gamma emitting nuclides even in larger scrap loads; • generally operated with individual settings; • absence of an alarm does not mean absence of activity. Metal industry: • generally considers a scrap load to contain radioactivity if RPM produces an alarm - alarms based on increase in dose rate above background; • accepts material where no measurable increase in dose rate is detected; • procedure laid down in standard contracts. • Nuclear industry: • needs clearance as integral part of material management; • cleared material will usually not trigger alarms at RPM if “general clearance levels” are used (0.1 Bq/g Co-60); • has agreed special procedures with some scrap dealers to accept material even cleared with higher clearance levels

  13. Extraction and recovery of nuclear fission products using hydrophobic, redox-active organometallic complexes

    We are investigating a new strategy for liquid-liquid extraction and recovery of Cs-137 and Sr-90 from aqueous nuclear waste and contaminated groundwater. The extractants are hydrophobic, redox-active derivatives of Ni(C2B9H11) and FeCp(C2B9H11). They are activated for extraction by reduction to the corresponding monoanions. The cesium and strontium cations are recovered from the organic phase by reoxidation (deactivation) of the anionic extractants back to the neutral species, which also allows for recovery and reuse (i.e., recycling) of the extractants. The reduction potentials of the parent compounds are 0.18 V and -0.08V respectively (acetonitrile, SCE). Therefore, the derivatives can be easily reduced and re-oxidized by many common substances. The redox potentials, relative solubilities in organic solvents and aqueous solution, and D values for extraction and recovery, which vary as a function of substituent groups on the ligands, will be discussed

  14. The IAEA coordinated research project: Production of Mo-99 using LEU fission or neutron activation

    Since late 2004, the IAEA has been planning and organizing a Coordinated Research Project (CRP) to assist countries interested in initiating indigenous, small-scale production of Mo-99 to meet local nuclear medicine requirements. The objective of the CRP is to provide interested countries with access to non-proprietary technologies and methods to produce Mo-99 using LEU foil or LEU mini-plate targets, or for the utilization of Mo-99 obtained by neutron activation of molybdenum trioxide target, e.g. through the use of gel generators. The work initiated with a significant consultancy meeting in Vienna directly following the RERTR 2004 International Meeting, and continued with a Mo-99 Potential Producers Workshop held in Buenos Aires, Argentina 17-20 May 2005. Five technology donor countries have been awarded IAEA Research Agreements, and five institutions in four countries have been awarded IAEA Research Contracts (a sixth institution is expected to be awarded a contract in the near future). The First Research Coordination Meeting (RCM) for this CRP will be held in Vienna December 6-9, 2005. The paper describes the background and history of the CRP, its planning and formulation, including the Buenos Aires workshop, plans for the first RCM, and the content of the project as well as the activities likely to take place over the next year. The results and experience gained from the CRP will help strengthen local capability for undertaking small scale Mo-99 production in participant countries. (author)

  15. Actinide, Activation Product and Fission Product Decay Data for Reactor-based Applications

    The UK Activation Product Decay Data Library was first released in September 1977 as UK-PADD1, to be followed by regular improvements on an almost yearly basis up to the assembly of UKPADD6.12 in March 2013. Similarly, the UK Heavy Element and Actinide Decay Data Library followed in December 1981 as UKHEDD1, with the implementation of various modifications leading to UKHEDD2.6, February 2008. Both the data content and evaluation procedures are defined, and the most recent evaluations are described in terms of specific radionuclides and the resulting consistency of their recommended decay-data files. New versions of the UKPADD and UKHEDD libraries are regularly submitted to the NEA Data Bank for possible inclusion in the JEFF library

  16. Comparative study of 99Mo/99mTc generators at base of synthesized gels starting from activation and fission 99Mo

    The 99mTc is used for diagnostic and therapy. It is produced starting from 99Mo, absorbed in chromatographic columns, loaded with alumina that absorb only 0.2% of 99Mo with high specific activities of 99Mo, obtained from the 235U fission. Given these conditions and limitations, new preparation procedures of 99Mo/99mTc generators, its have been developed, using zirconium molybdates gels that incorporates until 30% of 99Mo, conserve similar characteristics of quality and purity that the traditional generator. The radiochemical characteristics of the 99mTc elution, depend strongly on the gel preparation conditions. In particular, the present work has by object to determine the influence of the 99Mo used type, fission or activation product, during the gels synthesis, as well as the used air flow for the agitation in the gels preparation and its influence in the 99Mo/99mTc generators quality. When diminishing the flow of agitation air the efficiency it increases and in the radionuclide purity of the eluates and when using 99Mo from fission for the gels production it increases in an important way the elutriation efficiency, the radiochemical and radionuclide purity of the 99mTc eluates. (Author)

  17. Inspection Database

    U.S. Department of Health & Human Services — FDA is disclosing the final inspection classification for inspections related to currently marketed FDA-regulated products. The disclosure of this information is...

  18. Inspection Activities on Archeological Areas in Milan. Documents’ Analysis, Decay and Risks Conditions Evaluation

    Chiara Livraghi; Fabiana Pianezze; Matteo Scaltritti

    2015-01-01

    The project "Milano Archeologia" concerning the remains of the city of Milan in the Roman age, was based on specific methods and tools, such as the collection of data through the previous archive research, and the feedback of information through inspections and then direct contact with monuments. A very interesting and significant case is the funerary complex area of “San Vittore al Corpo”, in which are also preserved the remains of an impressive Imperial Mausoleum. The curtain, that defines ...

  19. NRU light water reflector inspections

    In 2009 May, the National Research Universal (NRU) calandria leaked. In the next year the calandria was inspected with six new techniques, repaired, and the repair inspected with four additional new techniques. The calandria is surrounded by a light water reflector vessel. Concerns that the same corrosion mechanism may have damaged the reflector vessel led to plans to inspect the full circumference of the reflector wall for corrosion damage, through a 64 mm diameter port, from 10 m away, while inspecting from the corroded surface. The ultrasonic technique is intended to produce a very fine inspection grid, through the corroded surface, using a very small probe body over the approximately 5 m2 to be inspected. The calandria vessel inspections were successfully performed, in a short time period, under difficult conditions. This paper will discuss Operating Experience (OPEX) from the 2009/2010 calandria wall inspections and industry dialogue that were applied to the Reflector Wall Inspection (RWI) project. Interaction with the CANDU Inspection Qualification Bureau (CIQB) on procedures, training plans, and mock-up training, led to improvements in how these activities were performed for the RWI project. Experience with shift turnover meetings led to improvements in how the inspection team captures lessons learned, trends issues, and eliminates reoccurring design and procedure problems. Experience with collected and analyzed data, inspection shift logs, and video captured from inspections and repairs, were used to improve inspection performance. Finally, OPEX from radiation/activation and the calibration process reduced dose through tool design and procedure changes. (author)

  20. Fission Research at IRMM

    Al-Adili A.; Fabry I.; Borcea R.; Zeynalov S.; Kornilov N.; Hambsch F.-J.; Oberstedt S.

    2010-01-01

    Fission Research at JRC-IRMM has a longstanding tradition. The present paper is discussing recent investigations of fission fragment properties of 238 U(n,f), 234 U(n,f), prompt neutron emission in fission of 252 Cf(SF) as well as the prompt fission neutron spectrum of 235 U(n,f) and is presenting the most important results.

  1. Determination of uranium fission products interference factors in neutron activation analysis; Determinacao de fatores de interferencia de produtos de fissao de uranio na analise por ativacao neutronica

    Ribeiro Junior, Ibere Souza

    2014-09-01

    Neutron activation analysis is a method used in the determination of several elements in different kinds of matrices. However, when the sample contains high U levels the problem of {sup 235}U fission interference occurs. A way to solve this problem is to perform the correction using the interference factor due to U fission for the radionuclides used on elemental analysis. In this study was determined the interference factor due to U fission for the radioisotopes {sup 141}Ce, {sup 143}Ce, {sup 140}La, {sup 99}Mo, {sup 147}Nd, {sup 153}Sm and {sup 95}Zr in the research nuclear reactor IEA-R1 on IPEN-CNEN/SP. These interference factors were determined experimentally, by irradiation of synthetic standards for 8 hours in a selected position in the reactor, and theoretically, determining the epithermal to neutron fluxes ratio in the same position where synthetic standards were irradiated and using reported nuclear parameters on the literature. The obtained interference factors were compared with values reported by other works. To evaluate the reliability of these factors they were applied in the analysis of studied elements in the certified reference materials NIST 8704 Buffalo River Sediment, IRMM BCR- 667 Estuarine Sediment e IAEA-SL-1 Lake Sediment. (author)

  2. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β− particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β− particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as εBaF2 / εEJ−313−5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency εBaF2 / εEJ−313−5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility

  3. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    Sibczynski, P.; Kownacki, J.; Moszyński, M.; Iwanowska-Hanke, J.; Syntfeld-Każuch, A.; Gójska, A.; Gierlik, M.; Kaźmierczak, Ł.; Jakubowska, E.; Kędzierski, G.; Kujawiński, Ł.; Wojnarowicz, J.; Carrel, F.; Ledieu, M.; Lainé, F.

    2015-09-01

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β- particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β- particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as epsilonBaF2 / epsilonEJ-313-5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency epsilonBaF2 / epsilonEJ-313-5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility.

  4. Development of an active 238uranium(VI)-fluoride detector chamber for precision experiments in photon-induced fission at the S-DALINAC

    The polarized injector SPIN at the S-DALINAC provides spin polarized electrons for circularly polarized bremsstrahlung with a high degree of polarization near the endpoint energy of the spectrum, enabling the search for forward-backward asymmetries of the light and heavy fission fragment originating from parity non-conservation in the photon-induced fission process of 238U. An active 238uranium(VI)-fluoride gas target has been developed along the lines of a simple Frisch grid ionization chamber to raise the luminosity and to study the properties of an 238uranium(VI)-fluoride/argon gas mixture. The active 238uranium(VI)-fluoride gas target has been filled with argon and 238uranium(VI)-fluoride using mass flow controllers. At different settings data has been acquired and interpreted. Instantly after filling the chamber with some 238uranium(VI)-fluoride the anode and cathode signal are severely lowered and gain only slowly. Apparently the 238uranium(VI)-fluoride acts as a very efficient electron collector because of its complexity and the high amount of fluorine and its electronegativity. Over time, the amount of gaseous 238uranium(VI)-fluoride is reduced and different processes are possible to explain this effect. In the present configuration of the active 238uranium(VI)-fluoride gas target no sound quantitative information on the properties of an 238uranium(VI)-fluoride/argon gas mixture can be given. Raising the luminosity for precision experiments in photon-induced fission at the S-DALINAC with an active 238uranium(VI)-fluoride gas target appears to be impossible.

  5. Energy released in fission

    The effective energy released in and following the fission of U-235, Pu-239 and Pu-241 by thermal neutrons, and of U-238 by fission spectrum neutrons, is discussed. The recommended values are: U-235 ... 192.9 ± 0.5 MeV/fission; U-238 ... 193.9 ± 0.8 MeV/fission; Pu-239 ... 198.5 ± 0.8 MeV/fission; Pu-241 ... 200.3 ± 0.8 MeV/fission. These values include all contributions except from antineutrinos and very long-lived fission products. The detailed contributions are discussed, and inconsistencies in the experimental data are pointed out. In Appendix A, the contribution to the total useful energy release in a reactor from reactions other than fission are discussed briefly, and in Appendix B there is a discussion of the variations in effective energy from fission with incident neutron energy. (author)

  6. Determination of fission cross-section and absolute fission yields using track-cum gamma-ray spectrometric technique

    The fission cross-section of 233Pa(2nth, f) using fission track technique has been determined for the first time using thermal neutron flux of the reactor APSARA. This is important from the point of view of advance heavy water reactor (AHWR), which is to be described. On the other hand, the yields of fission products in the fast neutron induced fission of minor actinides are important from the point accelerator driven sub critical system (ADSS). In view of that, absolute yields of fission products in the fast neutron induced fission of 238U, 237Np, 238,240Pu, 243Am and 244Cm have been determined using the fission track-cum gamma-ray spectrometric technique. The total number of fission occurring in the target was estimated by track technique, whereas the activities of the fission products have been determined using gamma-ray spectrometric technique. Detailed procedure and its importance are to be discussed. (author)

  7. Two non-destructive neutron inspection techniques: prompt gamma-ray activation analysis and cold neutron tomography

    Baechler, Sébastien; Dousse, Jean-Claude; Jolie, Jan

    2005-01-01

    Deux techniques d’inspection non-destructives utilisant des faisceaux de neutrons froids ont été développées à la source de neutrons SINQ de l’Institut Paul Scherrer : (1) l’analyse par activation neutronique prompte (PGAA) et (2) la tomographie neutronique. L’analyse par PGA (Prompt Gamma-ray Activation) est une méthode nucléaire qui permet de déterminer la concentration d’éléments présents dans un échantillon. Cette technique consiste à détecter les rayons gamma prompts émis par l’échantill...

  8. Activation analysis and waste management for blanket materials of multi-functional experimental fusion–fission hybrid reactor (FDS-MFX)

    The preliminary studies of the activation analysis and waste management for blanket materials of the multi-functional experimental fusion–fission hybrid reactor, i.e. Multi-Functional eXperimental Fusion Driven Subcritical system named FDS-MFX, were performed. The neutron flux of the FDS-MFX blanket was calculated using VisualBUS code and Hybrid Evaluated Nuclear Data Library (HENDL) developed by FDS Team. Based on these calculated neutron fluxes, the activation properties of blanket materials were analyzed by the induced radioactivity, the decay heat and the contact dose rate for different regions of the FDS-MFX blanket. The safety and environment assessment of fusion power (SEAFP) strategy, which was developed in Europe, was applied to FDS-MFX blanket for the management of activated materials. Accordingly, the classification and management strategy of activated materials after different cooling time were proposed for FDS-MFX blanket

  9. Fission fragment angular distributions and fission cross section validation

    surrounded by enriched uranium 235U so as to approach criticality with fast neutrons. The simulation predicts a multiplication factor keff in better agreement with the experiment (the deviation of 750 pcm is reduced to 250 pcm) when we replace the ENDF/B- VII.0 evaluation of the 237Np fission cross section by the n-TOF data. We also explore the hypothesis of deficiencies of the inelastic cross section in 235U which has been invoked by some authors to explain the deviation of 750 pcm. The large distortion that should be applied to the inelastic cross sections in order to reconcile the critical experiment with its simulation is incompatible with existing measurements. Also we show that the ν-bar of 237Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n-TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237Np. (author)

  10. Fission yield covariance generation and uncertainty propagation through fission pulse decay heat calculation

    Highlights: • Fission yield data and uncertainty comparison between major nuclear data libraries. • Fission yield covariance generation through Bayesian technique. • Study of the effect of fission yield correlations on decay heat calculations. • Covariance information contribute to reduce fission pulse decay heat uncertainty. - Abstract: Fission product yields are fundamental parameters in burnup/activation calculations and the impact of their uncertainties was widely studied in the past. Evaluations of these uncertainties were released, still without covariance data. Therefore, the nuclear community expressed the need of full fission yield covariance matrices to be able to produce inventory calculation results that take into account the complete uncertainty data. State-of-the-art fission yield data and methodologies for fission yield covariance generation were researched in this work. Covariance matrices were generated and compared to the original data stored in the library. Then, we focused on the effect of fission yield covariance information on fission pulse decay heat results for thermal fission of 235U. Calculations were carried out using different libraries and codes (ACAB and ALEPH-2) after introducing the new covariance values. Results were compared with those obtained with the uncertainty data currently provided by the libraries. The uncertainty quantification was performed first with Monte Carlo sampling and then compared with linear perturbation. Indeed, correlations between fission yields strongly affect the uncertainty of decay heat. Eventually, a sensitivity analysis of fission product yields to fission pulse decay heat was performed in order to provide a full set of the most sensitive nuclides for such a calculation

  11. Evaluation for the status of the IAEA inspection at PIEF and UF4 conversion plant (2001-2006)

    Kim, Hyun Sook; Lee, Byung Doo

    2007-12-15

    Safeguards implementation of nuclear material was carried out at facility level in an effort to support the peaceful nuclear activities in KAERI. Safeguards implementation is to fulfill the obligations associated with international agreements such as IAEA comprehensive safeguards agreement and additional protocol and bilateral nuclear cooperation agreements. IAEA inspection is the most important and basic factor of the safeguard implementation for the purpose of verifying whether all source or special fissionable material is diverted to nuclear weapons or other nuclear explosive devices. The status of the IAEA inspection at PIEF and UF4 conversion plant during the period from 2001 to 2006 is evaluated in this report.

  12. Evaluation for the status of the IAEA inspection at Hanaro and TRIGA Mark II and III reactor

    Safeguards implementation of nuclear material was carried out at facility level in an effect to support the peaceful nuclear activities in KAERI. Safeguards implementation is to fulfill the obligations associated with international agreements such as IAEA comprehensive safeguards agreement and additional protocol. IAEA inspection is the most important and basic factor of the safeguards implementation for the purpose of verifying whether all source or special fissionable material is diverted to nuclear weapons or other nuclear explosive devices. The status of the IAEA inspection at Hanaro and TRIGA Mark II and III reactor during 2001-2006 is evaluated in this report

  13. Fission Mass Yield Studies

    Mass yields from fission induced by a span of neutron energies up to 18 MeV have been measured for Th232, U235 and U238 target nuclei. Particular attention has been given to the dependence of symmetric fission yields on energy. To study the effect of angular momentum, fission yields from the U236 compound nucleus formed by alpha-particle irradiations of Th232 were also studied over the same span of excitation energies. A standard set of Pd109, Ag111, Pd112 and Ag113 symmetric fission yields was generally measured for all irradiations. In addition, yields of Eu156, Cs136 and 2.3-d Cd115 were measured for some selected combinations of projectile, energy and target nucleus. Assays for Zr97 and sometimes also Ba139 served as fission monitors. Altogether 150 fission yields were measured for these combinations of target nucleus, projectile and incident energy. About one-third of these were checked by replicated irradiations. At highest energies for the U236 compound nucleus the symmetric fission yield from alpha-particle-induced fission is about 13% higher than for neutron-induced fission. Dips in symmetric fission yield were observed at the energy onset of third-chance fission for each target and projectile. Some indication of a small central peak in the mass distribution was observed in the yields from U236 compound nucleus fission, but not from the Th233 compound nucleus fission. Detailed mathematical methods have been developed to separate the effects of fissions preceding and following neutron emission. These methods were used to remove the effects of second- and third-chance fissions from the measured symmetric fission yields. These calculated yields for first-chance fission show no dips with energy. The calculations also show that perhaps half the difference between symmetric yields for alpha- particle-induced fission of Th232 and neutron-induced fission of U235 is attributable to angular momentum effects. Both calculated first-chance yields and measured yields

  14. Complex fission phenomena

    Poenaru, D N; Greiner, W

    2005-01-01

    Complex fission phenomena can be studied in a unified way. Very general reflection asymmetrical equilibrium (saddle-point) nuclear shapes, may be obtained by solving an integro-differential equation without being necessary to specify a certain parametrization. The mass asymmetry in cold fission phenomena can be explained as the result of adding a phenomenological shell correction to the liquid drop model deformation energy. Applications to binary, ternary, and quaternary fission are outlined. Predictions of two alpha accompanied fission are experimentally confirmed.

  15. Fission Research at IRMM

    Al-Adili A.

    2010-03-01

    Full Text Available Fission Research at JRC-IRMM has a longstanding tradition. The present paper is discussing recent investigations of fission fragment properties of 238 U(n,f, 234 U(n,f, prompt neutron emission in fission of 252 Cf(SF as well as the prompt fission neutron spectrum of 235 U(n,f and is presenting the most important results.

  16. To fission or not to fission

    Pomorski, Krzysztof; Ivanyuk, Fedir A

    2016-01-01

    The fission-fragments mass-yield of 236U is obtained by an approximate solution of the eigenvalue problem of the collective Hamiltonian that describes the dynamics of the fission process whose degrees of freedom are: the fission (elongation), the neck and the mass-asymmetry mode. The macroscopic-microscopic method is used to evaluate the potential energy surface. The macroscopic energy part is calculated using the liquid drop model and the microscopic corrections are obtained using the Woods-Saxon single-particle levels. The four dimensional modified Cassini ovals shape parametrization is used to describe the shape of the fissioning nucleus. The mass tensor is taken within the cranking-type approximation. The final fragment mass distribution is obtained by weighting the adiabatic density distribution in the collective space with the neck-dependent fission probability. The neck degree of freedom is found to play a significant role in determining that final fragment mass distribution.

  17. Inspection and teachers’ emotions: An emotional evaluation of inspection

    Binali Tunç

    2015-02-01

    Full Text Available In the study, inspection is discussed in relation to the teachers’ feelings and emotions it creates before inspection, during inspection and after inspection process. Teacher’s emotions have been investigated intentionally as emotional side of education has been neglected. Education is closely related to the emotions of teachers, who are the most important producers of educational activities.Educational activities are reduced to standard activities and defined with simple explanations or single labels such as ‘good-bad’, ‘successful-unsuccessful’, ‘adequate-inadequate’. Inspection causes emotions to be neglected. Moreover, recently, it has been discussed that there are approaches and systems that suggest constant and multi-dimensional inspection instead of traditional inspection.Qualitative research model was used to understand of teacher emotions. A semi structured form was used for the 38 primary school teachers’ interviews. After teacher interviews were completed, we analyzed and compared the interviews. Participants’ expressions were checked in terms of correctness, potential validity and reliability problems such as misinterpretation.   The results of the study can be summarized as follows: There were no positive expressions related to the emotional impact of inspection on teachers. In addition, teachers felt that the inspectors were stressed, anxious, uneasy, accusatory, coercive, looking for defect and areas of unsuccessful teaching performance. Most of teachers reported that being observed and evaluated caused them to have negative emotions.Teachers’ perceptions about inspection are found to be negative. There are no statements that indicate there is a positive impression of inspection on teachers. The emotions that are experienced before inspection: pressure, hurry, stress, concern, tension, anxiety, worry, uncertainty; during inspection: stress, tension, anger, loss of strength, humiliation and lack of self

  18. How spontaneous fission was discovered

    The 70th anniversary of the discovery of spontaneous fission by the young Russian physicists Konstantin A. Petrzhak and Georgii N. Flerov is commemorated. The situation in the 1940s is described and the activities of the 2 scientists, including their involvement in the development of the A-bomb, is outlined. (P.A.)

  19. Progress in fission product nuclear data

    This is the ninth issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The main part of this report consists of unaltered original contributions which the authors have sent to IAEA/NDS. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission); Neutron reaction cross sections of fission products; Data related to the radioactive decay of fission products; Delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The eighth issue of this series has been published in July 1982 as INDC(NDS)-130. The present issue includes contributions which were received by NDS between 1 August 1982 and 25 June 1983

  20. Progress in fission product nuclear data

    This is the seventh issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: fission product yields (neutron induced and spontaneous fission); neutron reaction cross sections of fission products; data related to the radioactive decay of fission products; delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The sixth issue of this series has been published in June 1980 as INDC(NDS)-113/G+P. The present issue includes contributions which were received by NDS between 1 August 1980 and 25 May 1981

  1. Optimal allocation of inspection resources

    Allocation of inspection resources for international safeguards is considered as the problem of designing a complex system that is composed of individual inspection activities and that has the objective of detecting material loss. Optimization theory is applied in selecting those inspection activities that maximize a system performance measure within resource constraints. The method is applicable to a global allocation problem in which inspection resources are distributed throughout a hierarchy consisting of multiple countries, multiple facilities within each country, and multiple activities within each facility. 9 references

  2. The experience of Russian Federation in organization of customs control of fissionable and other radioactive materials

    Among the routine inspection tasks of customs offices are tasks stemming from international commitments of Russia to prevent proliferation of nuclear weapons and material that can be used for making these weapons. These tasks are: radiation monitoring of all vehicles, passengers, their luggage and goods crossing the state border; inspection of fissionable and radioactive materials (FRM) legally transported by participants in the foreign trade activities with a view to checking that the declared data fully correspond to the actual radioactive cargo. Organizational measures involve the Sheremetyevo customs office has a department whose personnel is specially trained in radiation monitoring and can operate radiometric and spectrometric instruments. These specialists are included in shifts on duty responsible for customs clearing and inspection and carry out continuous radiation monitoring of passengers and their luggage, vehicles and goods crossing the border. They work on the 24-hour basis, which allows quickly and skillfully localizing the detected radiation source and avoiding direct contact of customs, officers, airport personnel, and passengers with the radioactive item. Technical measures include provision and everyday use of radiation monitoring instrumentation, classified as: stationary equipment of primary radiation monitoring (SEPRM); hand-held instruments for additional radiation monitoring (RM); spectrometric equipment for control of legal FRM transport. The customs procedure for monitoring of fissionable and radioactive materials is divided into three stages. Stage I, primary RM is carried out by stationary FRM detection systems Yantar for customs applications installed on the customs inspection line next to the X-ray inspection equipment (XIE). Stage II, additional RM is carried out by officer who uses hand-held instruments to check the passenger's luggage for surface contamination; to perform primary identification of the detected radioactive source

  3. Heuristic use of mental map information gained from behavioural inspection of routines in daily activities (HUMMINGBIRDS)

    HANNES, Els; JANSSENS, Davy; Wets, Geert

    2007-01-01

    This research project aims at identifying the critical spatial factors in an individual’s mental map which influence daily activity travel behaviour in order to improve the agent-based modelling of activity travel behaviour by means of a computational process model. A qualitative travel survey and in depth interviews are used to identify the spatial factors that appear in the destination and travel mode choice heuristics of experts when discussing their activity space. Recorded interviews are...

  4. Fission neutron statistical emission

    The statistical model approach FINESSE (FIssion NEutronS' Statistical Emission) for the description of fission neutron multiplicities, energy spectra and angular distributions is described. Based on an extended Weisskopf ansatz and on a realistic temperature distribution it provides a fragment mass number dependent description of fission neutron data. Model parameters (optical potential, n/γ competition) were fixed on the basis of the 252Cf(sf) (nuclear data standard). Combined with a phenomenological fission model for predicting relevant fragment data as function of asymmetry. FINESSE can be applied to any fission reaction of actinides in the Th-Cf region without further parameter adjustment. Results are presented for 252Cf(sf) and neutron induced fission of 235U, 239Pu, 232Th. Effects of multiple-chance fission are discussed for 232Th(n,xnf) reacation. (author). 46 refs, 11 figs

  5. Hospital Inspections

    U.S. Department of Health & Human Services — Welcome to hospitalinspections.org, a website run by the Association of Health Care Journalists (AHCJ) that aims to make federal hospital inspection reports easier...

  6. Information-Driven Inspections

    New uranium enrichment capacity is being built worldwide in response to perceived shortfalls in future supply. To meet increasing safeguards responsibilities with limited resources, the nonproliferation community is exploring next-generation concepts to increase the effectiveness and efficiency of safeguards, such as advanced technologies to enable unattended monitoring of nuclear material. These include attribute measurement technologies, data authentication tools, and transmission and security methods. However, there are several conceptual issues with how such data would be used to improve the ability of a safeguards inspectorate such as the International Atomic Energy Agency (IAEA) to reach better safeguards conclusions regarding the activities of a State. The IAEA is pursuing the implementation of information-driven safeguards, whereby all available sources of information are used to make the application of safeguards more effective and efficient. Data from continuous, unattended monitoring systems can be used to optimize on-site inspection scheduling and activities at declared facilities, resulting in fewer, better inspections. Such information-driven inspections are the logical evolution of inspection planning - making use of all available information to enhance scheduled and randomized inspections. Data collection and analysis approaches for unattended monitoring systems can be designed to protect sensitive information while enabling information-driven inspections. A number of such inspections within a predetermined range could reduce inspection frequency while providing an equal or greater level of deterrence against illicit activity, all while meeting operator and technology holder requirements and reducing inspector and operator burden. Three options for using unattended monitoring data to determine an information-driven inspection schedule are to (1) send all unattended monitoring data off-site, which will require advances in data analysis techniques to

  7. Information-Driven Inspections

    Laughter, Mark D [ORNL; Whitaker, J Michael [ORNL; Lockwood, Dunbar [U.S. Department of Energy, NNSA

    2010-01-01

    New uranium enrichment capacity is being built worldwide in response to perceived shortfalls in future supply. To meet increasing safeguards responsibilities with limited resources, the nonproliferation community is exploring next-generation concepts to increase the effectiveness and efficiency of safeguards, such as advanced technologies to enable unattended monitoring of nuclear material. These include attribute measurement technologies, data authentication tools, and transmission and security methods. However, there are several conceptual issues with how such data would be used to improve the ability of a safeguards inspectorate such as the International Atomic Energy Agency (IAEA) to reach better safeguards conclusions regarding the activities of a State. The IAEA is pursuing the implementation of information-driven safeguards, whereby all available sources of information are used to make the application of safeguards more effective and efficient. Data from continuous, unattended monitoring systems can be used to optimize on-site inspection scheduling and activities at declared facilities, resulting in fewer, better inspections. Such information-driven inspections are the logical evolution of inspection planning - making use of all available information to enhance scheduled and randomized inspections. Data collection and analysis approaches for unattended monitoring systems can be designed to protect sensitive information while enabling information-driven inspections. A number of such inspections within a predetermined range could reduce inspection frequency while providing an equal or greater level of deterrence against illicit activity, all while meeting operator and technology holder requirements and reducing inspector and operator burden. Three options for using unattended monitoring data to determine an information-driven inspection schedule are to (1) send all unattended monitoring data off-site, which will require advances in data analysis techniques to

  8. NRU light water reflector inspections

    Lumsden, R.H.; Hebert, H.; Zahn, N.; Simpson, N.W. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2011-07-01

    In 2009 May, the National Research Universal (NRU) calandria leaked. In the next year the calandria was inspected with six new techniques, repaired, and the repair inspected with four additional new techniques. The calandria is surrounded by a light water reflector vessel. Concerns that the same corrosion mechanism may have damaged the reflector vessel led to plans to inspect the full circumference of the reflector wall for corrosion damage, through a 64 mm diameter port, from 10 m away, while inspecting from the corroded surface. The ultrasonic technique is intended to produce a very fine inspection grid, through the corroded surface, using a very small probe body over the approximately 5 m{sup 2} to be inspected. The calandria vessel inspections were successfully performed, in a short time period, under difficult conditions. This paper will discuss Operating Experience (OPEX) from the 2009/2010 calandria wall inspections and industry dialogue that were applied to the Reflector Wall Inspection (RWI) project. Interaction with the CANDU Inspection Qualification Bureau (CIQB) on procedures, training plans, and mock-up training, led to improvements in how these activities were performed for the RWI project. Experience with shift turnover meetings led to improvements in how the inspection team captures lessons learned, trends issues, and eliminates reoccurring design and procedure problems. Experience with collected and analyzed data, inspection shift logs, and video captured from inspections and repairs, were used to improve inspection performance. Finally, OPEX from radiation/activation and the calibration process reduced dose through tool design and procedure changes. (author)

  9. 3 D localization system for inspection activities in metallic plates; Sistema de localizacao em tres dimensoes para auxilio na atividade de inspecao em chapas metalicas

    Bonacin, Mario Vicente; Polli, Helton Luis; Czaikowski, Daniel Irineu; Arruda, Lucia Valeria Ramos de; Neves Junior, Flavio; Oliveira, Daniel Rossato de [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, Parana (Brazil)

    2008-07-01

    This work presents the development of a 3D localization system based on inertial sensors. The prototype aims for its application in the oil and gas industry, which presents deficiencies on automation of inspection procedures. Recent advances on the field of Nondestructive Testing (NDT) have contributed to automation of these inspections, but installation and removal of NDT equipment, as well as location measurements and data acquired processing, are still highly dependent on labour-human. However, only the double integration of data from the inertial sensors - position determination - does not reach the precision level required by inspection activity. It requires the use of techniques and methods to minimize errors. Different models and techniques can be applied to minimize these undesired effects in addition with filters as the Kalman filter, widely used on problems of estimation of trajectories and fusion of sensors. This paper presents the modeling and implementation of some of these techniques, obtaining interesting results. (author)

  10. Fast fission phenomena

    Experimental studies of fast fission phenomena are presented. The paper is divided into three parts. In the first part, problems associated with fast fission processes are examined in terms of interaction potentials and a dynamic model is presented in which highly elastic collisions, the formation of compound nuclei and fast fission appear naturally. In the second part, a description is given of the experimental methods employed, the observations made and the preliminary interpretation of measurements suggesting the occurence of fast fission processes. In the third part, our dynamic model is incorporated in a general theory of the dissipative processes studied. This theory enables fluctuations associated with collective variables to be calculated. It is applied to highly inelastic collisions, to fast fission and to the fission dynamics of compound nuclei (for which a schematic representation is given). It is with these calculations that the main results of the second part can be interpreted

  11. Slaughterhouse Inspection (Egypt). Training Manual : Guidelines for the Planning and Organisation of Training Activities

    Blomne Sopov, M.; Ghouti, C.A.; Benlafquih, R.; Vugt, Van, Jose; Latief, A.M.A.

    2014-01-01

    The training manual was prepared for the inspectors of slaughterhouses in Egypt to support the training activities of the General Organization for Veterinary Services (GOVS). The manual has two main parts: 1. Overview on how to design, organize, implement and evaluate training programs in general 2. Recommendation on how to design and facilitate training programs for the inspectors of slaughterhouses. Report CDI-14-004.

  12. Complex fission phenomena

    Poenaru, Dorin N.; Gherghescu, Radu A.; Greiner, Walter

    2005-01-01

    Complex fission phenomena are studied in a unified way. Very general reflection asymmetrical equilibrium (saddle point) nuclear shapes are obtained by solving an integro-differential equation without being necessary to specify a certain parametrization. The mass asymmetry in binary cold fission of Th and U isotopes is explained as the result of adding a phenomenological shell correction to the liquid drop model deformation energy. Applications to binary, ternary, and quaternary fission are ou...

  13. IAEA Inspections for Undeclared and Declared Activities: Is a More Robust Approach Needed?

    Mark Schanfein

    2009-07-01

    The United States has long supported a strong international safeguards system and for many years has served as the foremost supplier of technology, equipment, and training to the International Atomic Energy Agency (IAEA). In doing so, it drew in many instances on DOE sponsored R&D and training that was directed towards domestic safeguards and then adapted for IAEA purposes. This was relatively straightforward because of the strong overlap between the development of nuclear material accountancy measures needed for both domestic and international purposes. Two factors have emerged that have made this strong reliance on domestic measures less and less able to be a source of support for the IAEA. One is the shift by the IAEA safeguards system towards detecting undeclared activities. The second is the shift of domestic attention away from nuclear material accountancy and towards physical protection. As a result, a gap in US sponsored R&D and training relevant to international safeguards has developed. The NNSA Next Generation Safeguards Initiative and the DOE NA-22 Safeguards R&D program are intended to help fill this gap and, thereby, permit the U.S. to remain as the pre-eminent supplier of technology for international safeguards purposes. In this context, IAEA challenges have been examined from the perspective of detecting the diversion of nuclear material from declared stocks; detecting undeclared production of nuclear material and activities at locations declared under INFCIRC/153; and detecting undeclared nuclear material and activities elsewhere in a state. Of these, the detection of undeclared nuclear material and activities is, perhaps, the IAEA’s most significant challenge. It is a challenge that even the international community finds difficult to meet because of the scope and the geographic scale of the problem, the technical constraints, the knowledge required, and the significant resources needed to deploy effective systems world-wide (e.g., satellite

  14. Fission product yields

    Data are summed up necessary for determining the yields of individual fission products from different fissionable nuclides. Fractional independent yields, cumulative and isobaric yields are presented here for the thermal fission of 235U, 239Pu, 241Pu and for fast fission (approximately 1 MeV) of 235U, 238U, 239Pu, 241Pu; these values are included into the 5th version of the YIELDS library, supplementing the BIBFP library. A comparison is made of experimental data and possible improvements of calculational methods are suggested. (author)

  15. Intermediate energy nuclear fission

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)

  16. Inspection scheme

    As part of the Danish RERTR Program, three fuel elements with LEU U3O8-Al fuel and three fuel elements with LEU U3Si2-Al fuel were manufactured by NUKEM for irradiation testing in the DR-3 reactor at the Risoe National Laboratory in Denmark. The inspection scheme for the elements with U3O8-Al fuel is presented here as an illustration only. The inspection scheme for the elements with U3Si2-Al fuel was very similar. In this example, all document numbers, drawing numbers, and form numbers have been deleted or replaced with a generic identification. (author)

  17. IMPROVEMENT OF THE PRINCIPLES OF THE ORGANIZATION OF INSPECTION AND SUPERVISING ACTIVITY OF BANK OF RUSSIA

    Виктор Макарович Заернюк

    2013-04-01

    Full Text Available In article established practices of the organization of control and supervision of Bank of Russia of activity of the Russian commercial banks are considered.  The analysis is carried out and the assessment of a level of development of a substantial component of bank regulation and supervision is given.Purpose: Research of tendencies and problems in the organization of control and supervising activity of Bank of Russia at the present stage.Methodology: General scientific methods were used: analysis and synthesis, comparisons, generalizations, system approach. In the course of use of the actual material methods of the economical and statistical analysis were used.Results: The conclusion that the excessive and bureaucratized control from the Central bank interferes with dynamic development of the banking sector is drawn. It is required to generation of the new thinking which is expressing in transfer of accent from need of strict, in many respects of formal, application of bank instructions and regulations on formation of professional opinion of the controler, increase of its responsibility for results of checks.DOI: http://dx.doi.org/10.12731/2218-7405-2013-3-1

  18. Recent progress in analysis for fission products

    A great deal of progress has been achieved in analysis of fission products during the 1980s. In situ analysis of fission products and direct assay of radiowaste packages have been developed to meet the needs of radiowaste treatment and disposal. Activation analysis and non-radiometric method have been used to measure long-lived fission product nuclides. Their sensitivity is superior to that of traditional radiochemical analysis. Some new work on the Cherenkov counting technique and rapid radiochemical analysis has been published. The progress is reviewed from the point of view of methodology

  19. Thermal fission rates with temperature dependent fission barriers

    Zhu, Yi; Pei, Junchen

    2016-01-01

    The fission processes of thermal excited nuclei are conventionally studied by statistical models which rely on inputs of phenomenological level densities and potential barriers. Therefore the microscopic descriptions of spontaneous fission and induced fission are very desirable for a unified understanding of various fission processes. We propose to study the fission rates, at both low and high temperatures, with microscopically calculated temperature-dependent fission barriers and collective ...

  20. Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System

    Bromberger, B.; Bar, D.; Brandis, M.; Dangendorf, V.; Goldberg, M B; Kaufmann, F.; Mor, I.; Nolte, R.; SCHMIEDEL M.; Tittelmeier, K.; Vartsky, D.; H. Wershofen

    2012-01-01

    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and ga...

  1. Inspecting the microstructure of electrically active defects at the Ge/GeOx interface

    Fanciulli, Marco; Baldovino, Silvia; Molle, Alessandro

    2012-02-01

    High mobility substrates are important key elements in the development of advanced devices targeting a vast range of functionalities. Among them, Ge showed promising properties promoting it as valid candidate to replace Si in CMOS technology. However, the electrical quality of the Ge/oxide interface is still a problematic issue, in particular for the observed inversion of the n-type Ge surface, attributed to the presence of dangling bonds inducing a severe band bending [1]. In this scenario, the identification of electrically active defects present at the Ge/oxide interface and the capability to passivate or anneal them becomes a mandatory issue aiming at an electrically optimized interface. We report on the application of highly sensitive electrically detected magnetic resonance (EDMR) techniques in the investigation of defects at the interface between Ge and GeO2 (or GeOx), including Ge dangling bonds and defects in the oxide [2]. In particular we will investigate how different surface orientations, e.g. the (001) against the (111) Ge surface, impacts the microstructure of the interface defects. [1] P. Tsipas and A. Dimoulas, Appl. Phys. Lett. 94, 012114 (2009) [2] S. Baldovino, A. Molle, and M. Fanciulli, Appl. Phys. Lett. 96, 222110 (2010)

  2. Progress in fission product nuclear data. No. 13

    This is the 13th issue of a report series published by the Nuclear Data Section of the IAEA. The types of activities included are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission), neutron reaction cross-sections of fission products, data related to the radioactive decay of fission products, delayed neutron data of fission products and bumped fission product data (decay heat, absorption, etc.). The first part of the report consists of unaltered original data which the authors have sent to IAEA/NDS. The second part contains some recent references relative to fission product nuclear data, which were not covered by the contributions submitted, and selected papers from conferences. Part 3 contains requirements for further measurements

  3. Progress in fission product nuclear data. No. 14

    This is the 14th issue of a report series on Fission Product Nuclear Data published by the Nuclear Data Section of the IAEA. The types of activities included are measurements, compilations and evaluations of fission product yields, neutron reaction cross sections of fission products, data related to the radioactive decay of fission products, delayed neutron data from neutron induced and spontaneous fission, lumped fission product data. The first part of the report consists of unaltered original contributions which the authors have sent to IAEA/NDS. The second part contains some recent references relative to fission product nuclear data, which were not covered by the contributions submitted, and selected papers from conferences. The third part contains requirements for further measurements

  4. Energy partition in low energy fission

    Mirea, M.

    2011-01-01

    The intrinsic excitation energy of fission fragments is dynamically evaluated in terms of the time dependent pairing equations. These equations are corroborated with two conditions. One of them fixes the number of particles and the another separates the pairing active spaces associated to the two fragments in the vicinity of the scission configuration. The fission path is obtained in the frame of the macroscopic-microscopic model. The single particle level schemes are obtained within the two ...

  5. Muon-induced fission

    A review of recent experimental results on negative-muon-induced fission, both of 238U and 232Th, is given. Some conclusions drawn by the author are concerned with muonic atoms of fission fragments and muonic atoms of the shape isomer of 238U. (author)

  6. Fission gas detection system

    Colburn, Richard P.

    1985-01-01

    A device for collecting fission gas released by a failed fuel rod which device uses a filter to pass coolant but which filter blocks fission gas bubbles which cannot pass through the filter due to the surface tension of the bubble.

  7. Fission Xenon on Mars

    Mathew, K. J.; Marti, K.; Marty, B.

    2002-01-01

    Fission Xe components due to Pu-244 decay in the early history of Mars have been identified in nakhlites; as in the case of ALH84001 and Chassigny the fission gas was assimilated into indigenous solar-type Xe. Additional information is contained in the original extended abstract.

  8. Thermal fission rates with temperature dependent fission barriers

    Zhu, Yi

    2016-01-01

    \\item[Background] The fission processes of thermal excited nuclei are conventionally studied by statistical models which rely on inputs of phenomenological level densities and potential barriers. Therefore the microscopic descriptions of spontaneous fission and induced fission are very desirable for a unified understanding of various fission processes. \\item[Purpose] We propose to study the fission rates, at both low and high temperatures, with microscopically calculated temperature-dependent fission barriers and mass parameters. \\item[Methods] The fission barriers are calculated by the finite-temperature Skyrme-Hartree-Fock+BCS method. The mass parameters are calculated by the temperature-dependent cranking approximation. The thermal fission rates can be obtained by the imaginary free energy approach at all temperatures, in which fission barriers are naturally temperature dependent. The fission at low temperatures can be described mainly as a barrier-tunneling process. While the fission at high temperatures ...

  9. Federal environmental inspections handbook

    This Federal Environmental Inspection Handbook has been prepared by the Department of Energy (DOE), Office of Environmental Guidance, RCRA/CERCLA Division (EH-231). It is designed to provide DOE personnel with an easily accessible compilation of the environmental inspection requirements under Federal environmental statutes which may impact DOE operations and activities. DOE personnel are reminded that this Handbook is intended to be used in concert with, and not as a substitute for, the Code of Federal Regulations (CFR). Federal Register (FR), and other applicable regulatory documents

  10. Fission 2009 4. International Workshop on Nuclear Fission and Fission Product Spectroscopy - Compilation of slides

    This conference is dedicated to the last achievements in experimental and theoretical aspects of the nuclear fission process. The topics include: mass, charge and energy distribution, dynamical aspect of the fission process, nuclear data evaluation, quasi-fission and fission lifetime in super heavy elements, fission fragment spectroscopy, cross-section and fission barrier, and neutron and gamma emission. This document gathers the program of the conference and the slides of the presentations

  11. Monte-Carlo simulations of neutron-induced activation in a Fast-Neutron and Gamma-Based Cargo Inspection System

    Bromberger, B.; Bar, D.; Brandis, M.; Dangendorf, V.; Goldberg, M. B.; Kaufmann, F.; Mor, I.; Nolte, R.; Schmiedel, M.; Tittelmeier, K.; Vartsky, D.; Wershofen, H.

    2012-03-01

    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. The induced activity was determined by analyzing the gamma spectra. Based on the calculated radioactive inventory in the container, the dose levels due to the induced gamma radiation were calculated at several distances from the container and in relevant time windows after the irradiation, in order to evaluate the radiation exposure of the cargo handling staff, air crew and passengers during flight. The possibility of remanent long-lived radioactive inventory after cargo is delivered to the client is also of concern and was evaluated.

  12. Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons

    A program has been initiated to measure the energy dependence of selected high-yield fission products used in the analysis of nuclear test data. We present out initial work of neutron activation using a dual-fission chamber with quasi-monoenergetic neutrons and gamma-counting method. Quasi-monoenergetic neutrons of energies from 0.5 to 15 MeV using the TUNL 10 MV FM tandem to provide high-precision and self-consistent measurements of fission product yields (FPY). The final FPY results will be coupled with theoretical analysis to provide a more fundamental understanding of the fission process. To accomplish this goal, we have developed and tested a set of dual-fission ionization chambers to provide an accurate determination of the number of fissions occurring in a thick target located in the middle plane of the chamber assembly. Details of the fission chamber and its performance are presented along with neutron beam production and characterization. Also presented are studies on the background issues associated with room-return and off-energy neutron production. We show that the off-energy neutron contribution can be significant, but correctable, while room-return neutron background levels contribute less than <1% to the fission signal

  13. Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons

    Bhatia, C.; Fallin, B. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Gooden, M.E., E-mail: megooden@tunl.duke.edu [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Howell, C.R. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Kelley, J.H. [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Tornow, W. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Arnold, C.W.; Bond, E.M.; Bredeweg, T.A.; Fowler, M.M.; Moody, W.A.; Rundberg, R.S.; Rusev, G.; Vieira, D.J.; Wilhelmy, J.B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Becker, J.A.; Macri, R.; Ryan, C.; Sheets, S.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); and others

    2014-09-01

    A program has been initiated to measure the energy dependence of selected high-yield fission products used in the analysis of nuclear test data. We present out initial work of neutron activation using a dual-fission chamber with quasi-monoenergetic neutrons and gamma-counting method. Quasi-monoenergetic neutrons of energies from 0.5 to 15 MeV using the TUNL 10 MV FM tandem to provide high-precision and self-consistent measurements of fission product yields (FPY). The final FPY results will be coupled with theoretical analysis to provide a more fundamental understanding of the fission process. To accomplish this goal, we have developed and tested a set of dual-fission ionization chambers to provide an accurate determination of the number of fissions occurring in a thick target located in the middle plane of the chamber assembly. Details of the fission chamber and its performance are presented along with neutron beam production and characterization. Also presented are studies on the background issues associated with room-return and off-energy neutron production. We show that the off-energy neutron contribution can be significant, but correctable, while room-return neutron background levels contribute less than <1% to the fission signal.

  14. Chemical activity of noble gases Kr and Xe and its impact on fission gas accumulation in the irradiated UO2 fuel

    It is generally accepted that most of the insoluble inert gas atoms Xe and Kr produced during fissioning are retained in the fuel irradiated at a temperature lower than the threshold. Experimental data imply that we can assume that after irradiation exposure in excess of 1018 fissions/cm3 the single gas atom diffusion can be disregarded in description of fission gas behaviour. It is assumed that the vicinity of the fission fragment trajectory is the place of intensive irradiation induced chemical interaction of the fission gas products with UO2. Significant part of fission gas product is thus expected to be chemically bound in the matrix of UO2. Experiments with mixture of noble gases, coupled with theoretical calculations, provide strong evidence for direct bonds between Ar, Kr, or Xe atoms and the U atom of the CUO molecule. Because of its positive charge, the UO22+ ion, which is isoelectronic with CUO, should form even stronger bonds with noble gas atoms, which could lead to a growing number of complexes that contain direct noble gas - to - actinide bonds. Considering the huge amount of gas immobilised in the UO2 fuel the solution process and in consequence the re-solution process of rare gases is to be replaced by the chemical bonding process. This explains the fission gas accumulation in the irradiated UO2 fuel. (author)

  15. Decree-Law No. 48568 of 4 September 1968 - Competence of the J.E.N. to undertake scientific and technical inspections of private or public bodies involved in nuclear research or nuclear activities

    Under this Decree-Law, the Junta de Energia Nuclear (JEN) is empowered to inspect on a regular basis all establishments and installations involved in nuclear activities. These inspections are made to ensure that the installations are operated safely and efficiently and that radiation protection measures are properly applied. (NEA)

  16. Emission of fission products and other activities during the accident to Windscale Pile no. 1 in October 1957

    Information on the release of activity from Windscale during the accident of October 1957 is reviewed, and some previously unpublished data are given. The activities of 131I released to atmosphere, retained on the pile filters and washed out of the pile are compared with the activity in the channels involved in the fire. The information on the physical form of the released activity is summarised. (author)

  17. The non-proliferation experiment and gas sampling as an on-site inspection activity: A progress report

    The Non-proliferation Experiment (NPE) is contributing to the development of gas sampling methods and models that may be incorporated into future on-site inspection (OSI) activities. Surface gas sampling and analysis, motivated by nuclear test containment studies, have already demonstrated the tendency for the gaseous products of an underground nuclear test to flow hundreds of meters to the surface over periods ranging from days to months. Even in the presence of a uniform sinusoidal pressure variation, there will be a net flow of cavity gas toward the surface. To test this barometric pumping effect at Rainier Mesa, gas bottles containing sulfur hexaflouride and 3He were added to the pre-detonation cavity for the 1 kt chemical explosives test. Pre-detonation measurements of the background levels of both gases were obtained at selected sites on top of the mesa. The background levels of both tracers were found to be at or below mass spectrographic/gas chromatographic sensitivity thresholds in the parts-per-trillion range. Post-detonation, gas chromatographic analyses of samples taken during barometric pressure lows from the sampling sites on the mesa indicate the presence of significant levels (300--600 ppt) of sulfur hexaflouride. However, mass spectrographic analyses of gas samples taken to date do not show the presence of 3He. To explain these observations, several possibilities are being explored through additional sampling/analysis and numerical modeling. For the NPE, the detonation point was approximately 400 m beneath the surface of Rainier Mesa and the event did not produce significant fracturing or subsidence on the surface of the mesa. Thus, the NPE may ultimately represent an extreme, but useful example for the application and tuning of cavity gas detection techniques

  18. Phosphorylation-Independent Regulation of Atf1-Promoted Meiotic Recombination by Stress-Activated, p38 Kinase Spc1 of Fission Yeast

    Gao, Jun; Davidson, Mari K.; Wahls, Wayne P.

    2009-01-01

    Background Stress-activated protein kinases regulate multiple cellular responses to a wide variety of intracellular and extracellular conditions. The conserved, multifunctional, ATF/CREB protein Atf1 (Mts1, Gad7) of fission yeast binds to CRE-like (M26) DNA sites. Atf1 is phosphorylated by the conserved, p38-family kinase Spc1 (Sty1, Phh1) and is required for many Spc1-dependent stress responses, efficient sexual differentiation, and activation of Rec12 (Spo11)-dependent meiotic recombination hotspots like ade6-M26. Methodology/Principal Findings We sought to define mechanisms by which Spc1 regulates Atf1 function at the ade6-M26 hotspot. The Spc1 kinase was essential for hotspot activity, but dispensable for basal recombination. Unexpectedly, a protein lacking all eleven MAPK phospho-acceptor sites and detectable phosphorylation (Atf1-11M) was fully proficient for hotspot recombination. Furthermore, tethering of Atf1 to ade6 in the chromosome by a heterologous DNA binding domain bypassed the requirement for Spc1 in promoting recombination. Conclusions/Significance The Spc1 protein kinase regulates the pathway of Atf1-promoted recombination at or before the point where Atf1 binds to chromosomes, and this pathway regulation is independent of the phosphorylation status of Atf1. Since basal recombination is Spc1-independent, the principal function of the Spc1 kinase in meiotic recombination is to correctly position Atf1-promoted recombination at hotspots along chromosomes. We also propose new hypotheses on regulatory mechanisms for shared (e.g., DNA binding) and distinct (e.g., osmoregulatory vs. recombinogenic) activities of multifunctional, stress-activated protein Atf1. PMID:19436749

  19. Fission Fragments Discriminator

    Nuclear fission reaction between Uranium-235 nucleus and thermal neutron caused the high energy fission fragments with uncertainly direction. The particle direction discrimination was determined. The 2.5 x 3.0 mm2 polyethylene gratings with 1-6 mm thickness were used. The grating was placed between uranium screen that fabricated from ammonium-diurinate compound and polycarbonate nuclear track film recorder irradiated by neutron from Thai Research Reactor (TRR-1/M1) facility. The nuclear track density was inversely with grating thickness. It's only fission fragments normal to uranium screen pass through film recorder when grating thickness was 4-6 mm

  20. Zircon and apatite fission track analyses on mineralization ages and tectonic activities of Tuwu-Yandong porphyry copper deposit in northern Xinjiang, China

    2007-01-01

    The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different, but also fall into the Hercynian epoch. This study has achieved 9 zircon and 7 apatite fission track analysis results. The zircon fission track ages range from 158 Ma to 289 Ma and the apatite ages are between 64 Ma and 140 Ma. The mineralization accords with the regional tectonics in the copper district. We consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140-300℃ and retention temperature of ~250℃ for zircon fission track, and metallogenetic temperature of 120-350℃ in this ore district. Total three mineralization epochs have been identified, i.e., 289-276 Ma,232-200 Ma and 165-158 Ma, and indicate occurrence of the mineralization in the Indosinian and Yanshan epochs. Corresponding to apatite fission track ages, the three tectonic-mineralizing epochs are 140-132 Ma, 109-97 Ma and 64 Ma, which means age at about 100℃ after the mineralization. The three epochs lasted 146 Ma, 108 Ma and about 100 Ma from ~250℃ to ~100℃ and trend decrease from early to late. It is shown by the fission track modeling that this district underwent three stages of geological thermal histories, stable in Cretaceous and cooling both before Cretaceous and after 20 Ma.

  1. The fission fragment yields at the photofission of actinide nuclei

    The fission fragment yields of isotopes 101Mo, 135I, 135mCs were measured at the photo-fission of actinide nuclei 232Th, 238U, 237Np. These fission fragments have some peculiarities in nuclear structure or in practical using. The measurements were performed on the microtron bremsstrahlung at the Flerov Laboratory of Nuclear Reactions, JINR, at the electron energy 22 MeV. The activation method with an HPGe detector was used in these measurements of the yields

  2. Activities with regard to research and development of technics for SNR 300 reactor vessel in-service inspection procedures

    During the development of SNR 300 in-service inspection equipment, several branches were tested by experiment. In this report special steps for testing of manipulation systems and additional engineering equipment for control systems, such as coupling fluid circuit or camera cooling system are considered more in detail

  3. Sea bed mapping and inspection

    NONE

    2006-07-01

    The conference has 24 presentations on the topics: Sea bed mapping, inspection, positioning, hydrography, marine archaeology, remote operation vehicles and computerized simulation technologies, oil field activities and plans, technological experiences and problems. (tk)

  4. Fission fragment rocket concept

    A new propulsion scheme is outlined which may permit interstellar missions for spacecraft. This scheme is based on the idea of allowing fission fragments to escape from the core of a nuclear reactor. (orig.)

  5. Fission Systems for Mars Exploration

    Houts, Michael G.; Kim, T.; Dorney, D. J.; Swint, Marion Shayne

    2012-01-01

    Fission systems are used extensively on earth, and 34 such systems have flown in space. The energy density of fission is over 10 million times that of chemical reactions, giving fission the potential to eliminate energy density constraints for many space missions. Potential safety and operational concerns with fission systems are well understood, and strategies exist for affordably developing such systems. By enabling a power-rich environment and highly efficient propulsion, fission systems could enable affordable, sustainable exploration of Mars.

  6. A fission-fragment-sensitive target for X-ray spectroscopy in neutron-induced fission

    A fission-fragment-sensitive detector built for low-energy photon spectroscopy applications at the WNR 'white' neutron source at Los Alamos is described. The detector consists of eight layers of thin photovoltaic cells, onto which 1 mg/cm2 of pure 238U is deposited. The detector serves as an active target to select fission events from background and other reaction channels. The fairly small thickness of the detector with respect to transmission of 20-50 keV photons permits the measurement of prompt fission-fragment X-rays. Results with the GEANIE photon spectrometer are presented

  7. A fission-fragment-sensitive target for X-ray spectroscopy in neutron-induced fission

    Ethvignot, T; Giot, L; Casoli, P; Nelson, R O

    2002-01-01

    A fission-fragment-sensitive detector built for low-energy photon spectroscopy applications at the WNR 'white' neutron source at Los Alamos is described. The detector consists of eight layers of thin photovoltaic cells, onto which 1 mg/cm sup 2 of pure sup 2 sup 3 sup 8 U is deposited. The detector serves as an active target to select fission events from background and other reaction channels. The fairly small thickness of the detector with respect to transmission of 20-50 keV photons permits the measurement of prompt fission-fragment X-rays. Results with the GEANIE photon spectrometer are presented.

  8. Review of Fission Theory

    A survey of the present state of fission theory is attempted. The basic requirements of a theory of a physical process are outlined and against this background the state of fission theory is summarized, with special emphasis on developments in the past few years. An attempt is made to bring out the most important outstanding problems to be settled by future experiments and theory. (author)

  9. Fission product detection

    The response of photovoltaic cells to heavy ions and fission products have been tested on beam. Their main advantages are their extremely low price, their low sensitivity to energetic light ions with respect to fission products, and the possibility to cut and fit them together to any shape without dead zone. The time output signals of a charge sensitive preamplifier connected to these cells allows fast coincidences. A resolution of 12ns (F.W.H.M.) have been measured between two cells

  10. Spontaneous fission half-lives and their systematics

    Spontaneous fission is a phenomenon exhibited by heavy nuclei, which can be a major mode of decay of nuclei of elements heavier than thorium and can be a determining factor in their stability. For purposes of this paper, spontaneous fission will be considered a process in which a nucleus breaks up into two approximately equal parts. The emission of light nuclei or heavy ions such as 12C, 16O, or 32S will not be considered. This radioactive decay mode is often much smaller than the spontaneous fission decay mode, although this is not true in all cases. Barwick noted that this might indicate that the assumed half-life for spontaneous fission of some older experiments might be partially due to heavy fragment radioactivity. Other than taking note of this potential correction to spontaneous fission half-lives, this decay mode of heavy fragment radioactivity will be ignored. Excited states of some heavy nuclei may decay via spontaneous fission. These so-called fission isomers will not be discussed here. Electron capture (EC) or beta-delayed fission is a process in which prompt fission of a sufficiently excited daughter state occurs following population by EC or beta decay. The fission activity will appear to decay with the half-life of the parent and was earlier confused in some cases with SF. This process has been discussed in detail in a review and will not be considered in this paper

  11. Fission gas release (FGASRL)

    During irradiation of water reactor fuel rods, gaseous fission products are produced in the fuel and are slowly released to various voipd volumes in the fuel rods. The released fission gases degrade the initial fill gas thermal conductivity and thus change the thermal response of the fuel rods. Moreover, fuel rod internal pressure is increased so that the cladding mechanical response is affected. The fission gas release subcode FGASRL is intended for use in analytical codes which predict water reactor fuel pin behavior. The development effort was directed primarily at improving code predictions of the gas release model used in FRAP-S3 which overpredicts release of fuels irradiated at relatively low operating temperatures and therefore small gas release fractions. The fission gas release subcode (FGASRL) presented in the report describes a two-step gas release process: (a) fission gas release from fuel grains to the grain boundaries, and (b) fission gas release from the grain boundaries to internal free volume of the fuel pin

  12. Towards high accurate neutron-induced fission cross sections of 240,242Pu: Spontaneous fission half-lives

    Salvador-Castiñeira P.; Bryś T.; Eykens R.; Hambsch F.-J.; Moens A.; Oberstedt S.; Pretel C.; Sibbens G.; Vanleeuw D.; Vidali M.;

    2013-01-01

    Fast spectrum neutron-induced fission cross sections of transuranic isotopes are being of special demand in order to provide accurate data for the new GEN-IV nuclear power plants. To minimize the uncertainties on these measurements accurate data on spontaneous fission half-lives and detector efficiencies are a key point. High α-active actinides need special attention since the misinterpretation of detector signals can lead to low efficiency values or underestimation in fission fragment detect...

  13. Nucleon-induced fission at intermediate energies

    The absence of a satisfactory theoretical description to predict isotope yields as well as the need for experimental fragment mass and charge distributions at intermediate-energies form the motivation of this work. Like the objects under study, the research presented in this thesis consists two main parts. Part 1 concerns an activation experiment that has been performed at the 'Kernfysisch Versneller Instituut' (Nuclear Physics Accelerator Institute) in Groningen, Netherlands, using the AGOR cyclotron. Fission product yields have been measured resulting from 190 MeV proton-induced fission of natW, 197Au, natPb, 208Pb and 232Th. In Chapter 2 the experimental set up is discussed, followed in Chapter 3 by a description of the data analysis. The results on the reconstructed mass yields and the total fission cross sections are presented in Chapter 4. Part 2 is of a theoretical nature. The objective is to compute fission product mass yields from intermediate-energy nucleon-induced reactions. In the approach presented here, two stages can be distinguished. In the first stage the fission cross section is determined for the various fissioning isotopes as a function of their excitation energy in competition with other processes like pre-equilibrium decay and particle evaporation. ALICE-91 is a nuclear reaction code that takes care of this first stage. The second stage consists of constructing the total fission-fragment mass and charge distributions from the different contributions of all the equilibrated fissioning systems. Hence, a model is needed that gives a prediction for the fission-product mass yields in a large range of mass, charge, and excitation energy of the fissioning nucleus. For this purpose, the multi-modal random neck-rupture model by Brosa is extended with temperature-dependent shell and pairing corrections and a temperature-dependent LDM. The combination of ALICE-91 and the modified Brosa approach is used for the analysis of the experiments given in the

  14. Prompt Neutrons from Fission

    A survey is given of the present state of knowledge of the spectrum, angular distribution and number of prompt fission neutrons, as functions of incident neutron energy and individual fragment mass, for low-energy fission. The energy spectrum of prompt neutrons has been found to be of the same form (nearly Maxwellian) for many different types of fission. It has been shown that this type of spectrum is to be expected on the basis of evaporation from moving fragments, and theoretical predictions of the spectrum agree very accurately with experimental data. Some data are now available on the variation of the neutron spectrum with fragment mass and angle of emission. Only recently has it become possible to take accurate data on the angular distribution of the neutrons. It appears that the neutrons have the angular distribution to be expected if emitted almost isotropically from the moving fragments, with a possibility that some small fraction are not emitted in this way, but directly from the fissioning nuclide. Much work has been done on the variation of fission neutron number v with incident neutron energy for neutron-induced fission. The neutron number increases roughly linearly with energy, with a slope of about 0.15 n/MeV. There is now evidence that this slope changes somewhat with energy. This change must be associated with other changes in the-fission process. The most interesting recent discovery concerning fission neutrons is the strong dependence of neutron number on individual fragment mass. The data are being rapidly improved by means of the newer techniques of determining fragment mass yields from velocity and pulse-height data, and of determining neutron yields from cumulative mass yields. There is evidence of similar dependence of neutron yield on fragment mass in a number of cases. It has been suggested that this property is directly connected with the deformability of the fragments, and in particular with the near-spherical shapes of magic

  15. Observation of attachment ratio of fission products on solution aerosol

    Attachment behavior of fission products to solution aerosols has been observed to elucidate the role of chemical effects in the generation mechanism of fissionproduct aerosols. Primary aerosols generated from aqueous solution of sodium chloride or ammonium sulfate were passed through a fission-product chamber, and radioactive aerosols were generated by attaching fission products to the primary aerosol particles. Attachment ratios of the fission products on aerosols were estimated from activity measurements. It was found that the attachment ratio of the sodium chloride solution aerosol is larger than that of the ammonium sulfate solution aerosol. (author)

  16. Forecasting the Quantity and Activity of Fission Products in France in Future Years in the Light of Atomic Energy Development

    One of the most important problems connected with the development of electrical production of nuclear origin is the disposal or utilization of radioactive waste. It is a new problem, with far-reaching economic and safety implications. There is thus real value in an attempt to evaluate, even approximately, the activities which may be expected in coming years, having regard to present plans for nuclear power installations in order to define the limits of research needed for a solution to the disposal of radioactive wastes

  17. Feasibility of Producing Molybdenum-99 on a Small Scale Using Fission of Low Enriched Uranium or Neutron Activation of Natural Molybdenum

    This publication documents the work performed within the IAEA coordinated research project (CRP) on Developing Techniques for Small Scale Indigenous Molybdenum-99 Production Using LEU Fission or Neutron Activation. The project allowed participating institutions to receive training and information on aspects necessary for starting production of molybdenum-99 (99Mo) on a small scale, that is, to become national level producers of this medical isotope. Stable production of 99Mo is one of the most pressing issues facing the nuclear community at present, because the medical isotope technetium-99m (99mTc), which decays from 99Mo, is one of the most widely used radionuclides in diagnostic imaging and treatment around the world. In the past five years, there have been widespread shortages of 99Mo owing to the limited number of producers, many of which use ageing facilities. To assist in stabilizing the production of 99Mo, and to promote the use of production methods that do not rely on the use of highly enriched uranium (HEU), the IAEA initiated the abovementioned CRP on small scale 99Mo production using low enriched uranium (LEU) fission or neutron activation methods. The intention was to enable participating institutions to gain the knowledge necessary to become national level producers of 99Mo in the event of further global shortages. Some of the institutions that participated in the CRP have continued their work on 99Mo production, and are enlisting the assistance of other CRP members and the IAEA’s technical cooperation programme to set up a small scale production capability. In total, the CRP was active for six years, and concluded in December 2011. During the CRP, fourteen IAEA Member States took part; four research coordination meetings were held, and four workshops were held on operational aspects of 99Mo production, LEU target fabrication and waste management. Most participants carried out work related to the entire production process, from target assembly to

  18. Fission waves can oscillate

    Osborne, Andrew G

    2016-01-01

    Under the right conditions, self sustaining fission waves can form in fertile nuclear materials. These waves result from the transport and absorption of neutrons and the resulting production of fissile isotopes. When these fission, additional neutrons are produced and the chain reaction propagates until it is poisoned by the buildup of fission products. It is typically assumed that fission waves are soliton-like and self stabilizing. However, we show that in uranium, coupling of the neutron field to the 239U->239Np->239Pu decay chain can lead to a Hopf bifurcation. The fission reaction then ramps up and down, along with the wave velocity. The critical driver for the instability is a delay, caused by the half-life of 239U, between the time evolution of the neutron field and the production of 239Pu. This allows the 239Pu to accumulate and burn out in a self limiting oscillation that is characteristic of a Hopf bifurcation. Time dependent results are obtained using a numerical implementation of a reduced order r...

  19. METHODS FOR RECONSTRUCTION OF RADIONUCLIDE COMPOSITION AND ACTIVITY OF FISSION PRODUCTS ACCUMULATED IN THE IRRADIATED URANIUM AT THE MOMENT OF ITS RADIOCHEMICAL REPROCESSING AT PLANT “B”, “MAYAK” PA IN THE EARLY 1950s

    Glagolenko, Y. V.; Drozhko, Evgeniy G.; Mokrov, Y.; Rovny, Sergey I.; Lyzhkov, A. V.; Anspaugh, L. R.; Napier, Bruce A.

    2008-06-01

    The article describes calculation procedure for reconstruction of radionuclide composition and activity of fission fragments accumulated in the irridated uranium from “Mayak” PA graphite-uranium reactors at the moment, when irradiation is completed, and at the moment, when the uranium is transferred to radiochemical processing (plant B) in the early 1950s. The procedure includes a reactor model and a cooling pool model. It is based on archive data on monthly uranium unloading and loading in the reactor and in the cooling pool of each reactor. The objects of reconstruction include: order of reloading of uranium versus its location radius in the reactor core; duration of irradiation and radionuclide composition of fission fragments for each radius; order of uranium removal from the cooling pool; effective time of uranium storage in the pool; radionuclide composition and activity of fission fragments in the irradiated uranium delivered to radiochemical reprocessing daily and on average for each month. The model is intended for use in reconstruction of parameters of radionuclide release source into the atmosphere and the source of liquid radioactive waste generation at the “Mayak” PA radiochemical plant.

  20. Methods For Reconstruction Of Radionuclide Composition And Activity Of Fission Products Accumulated In The Irradiated Uranium At The Moment Of Its Radiochemical Reprocessing At Plant 'B', 'Mayak' PA In The Early 1950s

    The article describes calculation procedure for reconstruction of radionuclide composition and activity of fission fragments accumulated in the irradiated uranium from 'Mayak' PA graphite-uranium reactors at the moment, when irradiation is completed, and at the moment, when the uranium is transferred to radiochemical processing (plant B) in the early 1950s. The procedure includes a reactor model and a cooling pool model. It is based on archive data on monthly uranium unloading and loading in the reactor and in the cooling pool of each reactor. The objects of reconstruction include: order of reloading of uranium versus its location radius in the reactor core; duration of irradiation and radionuclide composition of fission fragments for each radius; order of uranium removal from the cooling pool; effective time of uranium storage in the pool; radionuclide composition and activity of fission fragments in the irradiated uranium delivered to radiochemical reprocessing daily and on average for each month. The model is intended for use in reconstruction of parameters of radionuclide release source into the atmosphere and the source of liquid radioactive waste generation at the 'Mayak' PA radiochemical plant.

  1. Chromosome aberrations induced in human lymphocytes by U-235 fission neutrons. Pt. 3. Evaluation of the effect of the induced α and β activity on the chromosomal aberration yield

    Aim: Further experiments were performed to explain a difference in chromosomal aberration yield found between samples cultivated immediately after fission neutron irradiation and samples which were cultivated with 96 h delay after irradiation. Material and Method: Human peripheral blood samples were irradiated in mixed fission neutron/gamma field (1800 s) and biological effect assessed in the mean of analysis of unstable chromosome aberrations with a time delay in culturing cells of 12, 24, 48 and 96 h. Additional measurements were performed on irradiated and blank blood samples with the aim to detect any increase in α and β activity after fission neutron irradiation. No difference was found. Results were compared to theoretically calculated values of the α and β activity released from natural radioactive isotopes. Result and Conclusion: As a conclusion it is shown that in our experimental conditions the secondary effects resulting from nuclear transformations of natural or induced radioactive isotopes, recoil reactions and accompanying α, β, and γ radiation are not the reason for the increase observed in chromosomal aberration yield in blood samples cultured with a time delay of at least 24 hours. (orig.)

  2. Conceptual Analysis of Criticality Aspects of Fission Electric Cell Reactors

    The U.S. Department of Energy's Nuclear Energy Research Initiative Direct Energy Conversion project has a goal of developing direct energy conversion (DEC) processes suitable for commercial development. DEC is any fission process that returns usable energy with no intermediate thermal process. This project includes the study of the fission electric cell (FEC). In the FEC, fission fragments exit the fuel element cathode and are collected by the cell anode. Previous work [1] has shown the potential of FECs with theoretical efficiencies up to 60%. Inspection of this work indicates the need for additional system criticality studies prior to any conclusions regarding the final FEC reactor configuration. This paper outlines the development of models to facilitate reactor criticality design decisions. The models address criticality, design life, and reactor configuration. In addition, this paper proposes future work to complete the criticality model. The direct energy conversion concept converts nuclear energy to electrical energy without the use of a Carnot cycle based system. Kinetic energy of the highly charged fission fragments is converted directly into electrical potential using strong magnetic fields to separate the positive fission fragments from the electrons that are also produced during the fission process. A parametric analysis is performed using Monte Carlo N-Particle (MCNP) [2] simulations to calculate criticality for exact geometric models. The effect on criticality of changing enrichment, number of cells, size of cells, fuel thickness, and reactor size is determined. Heavy water, helium, and beryllium are each considered for a reflector design. (authors)

  3. Inspection technologies -Development of national safeguards technology-

    17 facility regulations prepared by nuclear facilities according to the Ministerial Notices were evaluated. Safeguards inspection activities under Safeguards are described. Safeguards inspection equipments and operation manuals to be used for national inspection are also described. Safeguards report are produced and submitted to MOST by using the computerized nuclear material accounting system at state level. National inspection support system are developed to produce the on-site information for domestic inspection. Planning and establishment of policy for nuclear control of nuclear materials, international cooperation for nuclear control, CTBT, strengthening of international safeguards system, and the supply of PWRs to North Korea are also described. (author). 43 tabs., 39 figs

  4. Current position on fission product behavior

    The following phenomena are treated and modeled: fission product release from fuel, both in-vessel and ex-vessel; fission product deposition in the primary system, fission product deposition in the containment, and fission product revolatization

  5. Development and characterisation of 9Cr ODS and reduced activation ferritic/martensitic steels for fast fission and fusion reactors

    This paper presents the results of the indigenous efforts at IGCAR towards developing a 9Cr Oxide Dispersion Strengthened (ODS) and Reduced Activation Ferritic Martensitic (RAFM) steels for the Fast Breeder Reactors (FBR) and fusion program in India. The sodium cooled fast reactors require development of high temperature radiation resistant materials for achieving high fuel burn-up of 200GWd/t (∼160 dpa) or higher, which is one of the key factors for their efficient and economical operation. Ferritic/Martensitic steels (9-12% Cr) although exhibit higher void swelling resistance than austenitics, have poor high temperature creep strength, which limits the operating temperatures to ∼550 deg. C. Oxide dispersion strengthening (ODS) is a promising means of extending the creep resistance of F/M steels beyond 650 deg. C together with the advantages of high thermal conductivity and low swelling. Based on these well known principles, a developmental effort has been taken up to fabricate clad tubes using the yttria strengthened 9Cr ferritic steel. A small amount of Ti addition resulted in very fine mixed oxide particles of Y and Ti, thus improving creep rupture strength significantly. The process of clad tubes fabrication involved mechanical milling of alloy powders, consolidation by hot extrusion and tube formation by cold pilgering. Further, the particle size distribution studied using Analytical and High Resolution Electron Microscopy at intermediate stages and in the product showed a distribution of Y2O3 particles predominantly in the size range of 5-20nm. The process parameters have been optimized and tubes of outer diameter 6.6 mm, thickness 0.48 mm and length 1500mm have been produced. The RAFM steel for the test blanket module of International Thermonuclear Experimental Reactor (ITER) project has also been developed. The steel conforming to specifications has been achieved by replacement of Mo and Nb (elements that lead to high induced radioactivity) by W and Ta

  6. Principles for National Inspections under IS Environment

    In 1997 the ROK introduced 'National Inspection' for nuclear material accountancy in its territory, and continues its independent verification activities besides the IAEA inspections. In 2004 the Additional Protocol was effectuated, and the IAEA finally decided to apply Integrated Safeguard to the ROK in 2008. This was a very significant milestone for Korea's nuclear transparency, which means that there are only nuclear activities with peaceful purposes and no more undeclared or suspicious nuclear activities. With this turning point, the previous inspection activities . IAEA and national inspections all together are to be adjusted to the new environment, i.e. Integrated Safeguards. Even for the SSAC, the objectives of national inspections are needed to be defined newly and its philosophy as well. In this paper, the principles of national inspections are suggested to address any verification challenges from the IS environment

  7. Fission modelling with FIFRELIN

    Litaize, Olivier; Serot, Olivier; Berge, Léonie

    2015-12-01

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ , e-) . The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for the

  8. Fission modelling with FIFRELIN

    Litaize, Olivier; Serot, Olivier; Berge, Leonie [CEA, DEN, DER, SPRC, Saint Paul Lez Durance (France)

    2015-12-15

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ, e{sup -}). The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for

  9. Fission modelling with FIFRELIN

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ, e-). The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for the

  10. Characteristics of Coulomb fission

    Oberacker, Volker; Greiner, Walter; Kruse, Hans; Pinkston, William T.

    2006-01-01

    Within an extended semiquantal theory we perform large-sized coupled-channel calculations involving 260 collective levels for Coulomb fission of 238U. Differential Coulomb fission cross sections are studied as a function of bombarding energy and impact parameter for several projectiles. In the Xe + U case, total cross sections are also given. We find a strong dependence on projectile charge number, PCF(180°)∼(Zp)6 in the region 50≤Zp≤92 for a fixed ratio E/ECoul, which might...

  11. Fission product solvent extraction

    Two main objectives concerning removal of fission products from high-level tank wastes will be accomplished in this project. The first objective entails the development of an acid-side Cs solvent-extraction (SX) process applicable to remediation of the sodium-bearing waste (SBW) and dissolved calcine waste (DCW) at INEEL. The second objective is to develop alkaline-side SX processes for the combined removal of Tc, Cs, and possibly Sr and for individual separation of Tc (alone or together with Sr) and Cs. These alkaline-side processes apply to tank wastes stored at Hanford, Savannah River, and Oak Ridge. This work exploits the useful properties of crown ethers and calixarenes and has shown that such compounds may be economically adapted to practical processing conditions. Potential benefits for both acid- and alkaline-side processing include order-of-magnitude concentration factors, high rejection of bulk sodium and potassium salts, and stripping with dilute (typically 10 mM) nitric acid. These benefits minimize the subsequent burden on the very expensive vitrification and storage of the high-activity waste. In the case of the SRTALK process for Tc extraction as pertechnetate anion from alkaline waste, such benefits have now been proven at the scale of a 12-stage flowsheet tested in 2-cm centrifugal contactors with a Hanford supernatant waste simulant. SRTALK employs a crown ether in a TBP-modified aliphatic kerosene diluent, is economically competitive with other applicable separation processes being considered, and has been successfully tested in batch extraction of actual Hanford double-shell slurry feed (DSSF)

  12. Data summary report for fission product release test VI-4

    This was the fourth in a series of high-temperature fission product release tests in a vertical test apparatus. The test specimen, a 15.2-cm-long section of a fuel rod from the BR3 reactor in Belgium, had been irradiated to a burnup of 47 MWd/kg. In simulation of a severe accident in a light-water reactor, it was heated in hydrogen in a hot cell-mounted test apparatus to a maximum test temperature of 2400 K for a period of 20 min. The released fission products were collected on components designed to facilitate sampling and analysis. On-line radioactivity measurements and posttest inspection revealed that the fuel had partially collapsed at about the time the cladding melted. Based on fission product inventories measured in the fuel or calculated by ORIGEN2, analyses of test components showed total releases from the fuel of 85% for 85Kr, 106Ru, 3.9% for 125Sb, 96% for both 134Cs and 137Cs, and 13% for 154Eu. Large fractions of the released fission products (up to 96% of the 154Eu) were retained in the furnace. Small release fractions for several other fission products -- Rb, Br, Sr, Te, I, and Ba -- were detected also. In addition, very small amounts of fuel material -- uranium and plutonium -- were released. Total mass release from the furnace to the collection system, which included fission products, fuel material, and structural materials, was 0.40g, with 40% of this material being deposited as vapor and 60% of it being collected as aerosols. The results from this test were compared with previous tests in this series and with an in-pile test at similar conditions at Sandia National Laboratories. There was no indication that the mode of heating (fission heat vs radiant heat) significantly affected fission product release. 24 refs., 25 figs., 14 tabs

  13. Discoveries of isotopes by fission

    M Thoennessen

    2015-09-01

    Of the about 3000 isotopes presently known, about 20% have been discovered in fission. The history of fission as it relates to the discovery of isotopes as well as the various reaction mechanisms leading to isotope discoveries involving fission are presented.

  14. Microscopic Description of Induced Fission

    Schunck, N

    2013-01-01

    Selected aspects of the description of neutron-induced fission in 240Pu in the framework of the nuclear energy density functional theory at finite temperature are presented. In particular, we discuss aspects pertaining to the choice of thermodynamic state variables, the evolution of fission barriers as function of the incident neutron energy, and the temperatures of the fission fragments.

  15. Fission dynamics of hot nuclei

    Santanu Pal; Jhilam Sadhukhan

    2014-04-01

    Experimental evidence accumulated during the last two decades indicates that the fission of excited heavy nuclei involves a dissipative dynamical process. We shall briefly review the relevant dynamical model, namely the Langevin equations for fission. Statistical model predictions using the Kramers’ fission width will also be discussed.

  16. An improved technique for fission track dating

    The necessity of improving the fission track dating (FTD) technique both at home and abroad is illustrated. The ways of making such improvement are also proposed. It is suggested to calibrate the constant b value of the uranium standard glass by using the method of fission products activity. The 3 kinds of uranium standard glass which have been calibrated are NBS SRM962a, UB1 and UB2. An established new method σ·Φ ρd/b, to measure neutron fluence, avoids the influence of the varying neutron spectrum on measuring neutron fluence. The improved etching technique for fission tracks in zircon adopted a two-step method which includes the molten alkali system etching using NaOH + KOH and the mixed acid system etching using HNO3 + HF; this technique results in adequate track etching, increased track clarity and less interference. In this way the intensity of tracks is authentically reflected. Dividing angular zone in accordance with the angular distribution of spontaneous fission track on the crystal surface of minerals to count the tracks and using the improved etching technique to remove the non-uniform angular distribution of spontaneous fission tracks in zircon, ensure the accuracy of tracks count. The improved FTD techniques were used to finish Laboratory Standardized Calibration. The tests using international FTD age standards samples have proved that above mentioned techniques are reliable and practical in obtaining the accurate FTD data. (8 tabs.; 3 figs.)

  17. Investigating Prompt Fission Neutron Emission from 235U(n,f) in the Resolved Resonance Region

    Göök Alf; Hambsch Franz-Josef; Oberstedt Stephan

    2016-01-01

    Investigations of prompt emission in fission is of importance in understanding the fission process in general and the sharing of excitation energy among the fission fragments in particular. Experimental activities at IRMM on prompt neutron emission from fission in response to OECD/NEA nuclear data requests is presented in this contribution. Main focus lies on currently on-going investigations of prompt neutron emission from the reaction 235U(n,f) in the region of the resolved resonances. For ...

  18. Lunar surface fission power supplies: Radiation issues

    A lunar space fission power supply shield that uses a combination of lunar regolith and materials brought from earth may be optimal for early lunar outposts and bases. This type of shield can be designed such that the fission power supply does not have to be moved from its landing configuration, minimizing handling and required equipment on the lunar surface. Mechanisms for removing heat from the lunar regolith are built into the shield, and can be tested on earth. Regolith activation is greatly reduced compared with a shield that uses only regolith, and it is possible to keep the thermal conditions of the fission power supply close to those seen in free space. For a well designed shield, the additional mass required to be brought from earth should be less than 1,000 kg. Detailed radiation transport calculations confirm the feasibility of such a shield

  19. Fission product data library

    A library is described of data for 584 isotopes of fission products, including decay constants, branching ratios (both burn-up and decay), the type of emitted radiation, relative and absolute yields, capture cross sections for thermal neutrons, and resonance integrals. When a detailed decay scheme is not known, the mean energies of beta particles and neutrino and gamma radiations are given. In the ZVJE SKODA system the library is named BIBFP and is stored on film No 49 of the NE 803 B computer. It is used in calculating the inventory of fission products in fuel elements (and also determining absorption cross sections for burn-up calculations, gamma ray sources, heat generation) and in solving radioactivity transport problems in the primary circuit. It may also be used in the spectrometric method for burn-up determination of fuel elements. The library comprises the latest literary data available. It serves as the basis for library BIBGRFP storing group constants of fission products with independent yields of isotopes from fission. This, in turn, forms the basis for the BIBDN library collecting data on the precursors of delayed neutron emitters. (author)

  20. Evaporation residue formation competing with the fission process in the 197Au+16O, 12C reactions and fission barriers at a specified J window

    Evaporation-residue excitation functions for 16O and 12C+197Au reactions were measured by means of the activation technique. The competition between evaporation and fission of the compound nuclei was studied by comparing the observed evaporation-residue data with the published fission excitation functions. A newly devised analysis was applied in order to deduce a fission barrier height at a specified angular momentum and determine the relevant fissioning nucleus as well. We found the fission barriers to be 8.2 MeV for the 211Fr nucleus at 16 ℎ and 8.2 MeV for the 207At nucleus at 27 ℎ. (orig.)

  1. Fission yields in the thermal neutron fission of plutonium-239

    Fission yields for 27 mass numbers were determined in the thermal neutron fission of 239Pu using high resolution gamma ray spectrometry and radiochemical method. The results obtained using gamma ray spectrometry and from the investigations on the fission yield of 99Mo using radiochemical method were reported earlier. These data along with fission yields for 19 mass numbers determined using radiochemical method formed a part of Ph.D. thesis. The data given here are a compilation of all the results and are presented considering the neutron temperature correction to 239Pu fission cross-section which is used for calculating the total number of fissions in these studies. A comparison is made of the resulting fission yield values with the latest experimentally determined values and those given in two recent compilations. (author)

  2. A study on the development and application of models for the activities of long-lived fission products at operating PWR

    It requires estimating difficult-to-measure (DTM) radionuclides, especially PDTM (particularly DTM) radionuclides such as 129I and 99Tc, in the waste package generated from nuclear power plants (NPPs) prior to shipment to disposal facility. These radionuclides are critical nuclides for the disposal of low and intermediate level waste because they dominate radiation dose through ground water. Therefore, their activities in each waste package should be accurately identified prior to disposal. However, their activities cannot be analyzed by routine measurement techniques used in NPPs because these PDTM radionuclides are non-gamma emitters. Therefore, instead of direct measurement, scaling factor method is typically used to estimate the quantity of the PDTM radionuclides in the waste package. The scaling factor is empirically derived ratio or correlation between a reference gamma emitting radionuclide, which can be easily measured at NPPs, and the non-gamma emitting radionuclide. The scaling factor is typically derived from a set of waste samples analyzed at commercial laboratories for both gamma and DTM radionuclides. However, in general, the concentrations of PDTM radionuclides in low-level waste are too low to be detected by the conventional measurement techniques i.e., photon counting method. When the lower limit of detection rather than the actually analyzed concentration is used for scaling factor, the determination of the scaling factor value is difficult but also the value generally involves a large uncertainty. In addition, the activity of radionuclide in radioactive wastes can be highly overestimated. Therefore, theoretical approaches have been proposed as a means of estimating activity or scaling factor for PDTM radionuclides, especially 129I. Also, evaluations of the 129I inventory are generally based on the release of related fission products from the source term such as defective fuel and tramp uranium. However, in these approaches, the ratio of the

  3. Linac based photofission inspection system employing novel detection concepts

    Stevenson, John, E-mail: jstevenson@rapiscansystems.com [Rapiscan Laboratories, Inc., 520 Almanor Avenue, Sunnyvale, CA 94085 (United States); Gozani, Tsahi, E-mail: tgozani@rapiscansystems.com [Rapiscan Laboratories, Inc., 520 Almanor Avenue, Sunnyvale, CA 94085 (United States); Elsalim, Mashal; Condron, Cathie; Brown, Craig [Rapiscan Laboratories, Inc., 520 Almanor Avenue, Sunnyvale, CA 94085 (United States)

    2011-10-01

    MV Bremsstrahlung spectrum above the photofission 'threshold' of about 6 MeV, the X-ray beam induces numerous fissions if nuclear material is present. The PBAR system looks for the two most prolific fission signatures to confirm the presence of special nuclear materials (SNM). These are prompt neutrons and delayed gamma rays. The PBAR system uses arrays of two types of fast and highly efficient gamma ray detectors: plastic and fluorocarbon scintillators. The latter serves as a detector of fission prompt neutrons using the novel threshold activation detector (TAD) concept as well as a very efficient delayed gamma ray detector. The major advantage of TAD for detecting the prompt neutrons is its insensitivity to the intense source related backgrounds. The current status of the system and experimental results will be shown and discussed.

  4. Linac based photofission inspection system employing novel detection concepts

    Stevenson, John; Gozani, Tsahi; Elsalim, Mashal; Condron, Cathie; Brown, Craig

    2011-10-01

    Bremsstrahlung spectrum above the photofission "threshold" of about 6 MeV, the X-ray beam induces numerous fissions if nuclear material is present. The PBAR system looks for the two most prolific fission signatures to confirm the presence of special nuclear materials (SNM). These are prompt neutrons and delayed gamma rays. The PBAR system uses arrays of two types of fast and highly efficient gamma ray detectors: plastic and fluorocarbon scintillators. The latter serves as a detector of fission prompt neutrons using the novel threshold activation detector (TAD) concept as well as a very efficient delayed gamma ray detector. The major advantage of TAD for detecting the prompt neutrons is its insensitivity to the intense source related backgrounds. The current status of the system and experimental results will be shown and discussed.

  5. Linac based photofission inspection system employing novel detection concepts

    Bremsstrahlung spectrum above the photofission 'threshold' of about 6 MeV, the X-ray beam induces numerous fissions if nuclear material is present. The PBAR system looks for the two most prolific fission signatures to confirm the presence of special nuclear materials (SNM). These are prompt neutrons and delayed gamma rays. The PBAR system uses arrays of two types of fast and highly efficient gamma ray detectors: plastic and fluorocarbon scintillators. The latter serves as a detector of fission prompt neutrons using the novel threshold activation detector (TAD) concept as well as a very efficient delayed gamma ray detector. The major advantage of TAD for detecting the prompt neutrons is its insensitivity to the intense source related backgrounds. The current status of the system and experimental results will be shown and discussed.

  6. Aspects of Inspection Planning

    Faber, M. H.; Sørensen, John Dalsgaard

    Inspection planning for systems is considered with special emphasis to the effect of the quality of inspections on the system reliability and the probability of repair. Inspection quality is described and discussed in terms of inspection reliability and inspection coverage where the latter is set...... theoretical framework for updating of the reliability of components and systems on the basis of inspection results is outlined. Systems representative for inspection planning of different engineering systems subjected to typical deterioration processes are presented. Numerical simulation studies are performed...... on the presented systems and the effect of inspection reliability and coverage is investigated for systems of different sizes. The results of the studies illustrate the effect of inspections in practical inspection problems and can be used as an initial guideline for selecting the quality of...

  7. FISA-2009 Conference on Euratom Research and Training Activities: Nuclear Fission - Past, Present and Future (Generation-II, -III and -IV + Partitioning and Transmutation)

    This paper is an introduction to the research and training activities carried out under the Euratom 7th Framework Programme (FP7, 2007-2011) in the field of nuclear fission science and technology, covering in particular nuclear systems and safety, and including innovative reactor systems and partitioning and transmutation. It is based on the more than 40 invited lectures that were delivered by Euratom project coordinators and keynote speakers at the FISA-2009 Conference (), organised by the European Commission DG Research, 22-24 June 2009, Prague, Czech Republic. The Euratom programme must be considered in the context of current and future nuclear technology and the respective research effort: ·Generation-II (i.e. yesterday, NPP construction 1970-2000): safety and reliability of nuclear facilities and energy independence in order to ensure security of supply worldwide; ·Generation-III (i.e. today, construction 2000-2040+): continuous improvement of safety and reliability, and increased industrial competitiveness in a growing energy market; ·Generation-IV (i.e. tomorrow, construction from 2040) for increased sustainability though optimal utilisation of natural resources and waste minimisation, and increased proliferation resistance. Consequently, the focus of the lectures devoted to Generation-II and -III is on the major scientific challenges and technological developments needed to guarantee safety and reliability, in particular issues associated with plant lifetime extension and operation. The focus of the lectures devoted to Generation-IV is on the design objectives and associated research issues that have been agreed upon internationally, in particular the ambitious criteria and technology goals established at the international level by the Generation-IV International Forum (GIF). In the future, electricity must continue to be produced competitively, and in addition high temperature process heat may also be required, while exploiting a maximum of fissile and

  8. Detection and Inspection of Steel Bars in Reinforced Concrete Structures Using Active Infrared Thermography with Microwave Excitation and Eddy Current Sensors.

    Szymanik, Barbara; Frankowski, Paweł Karol; Chady, Tomasz; John Chelliah, Cyril Robinson Azariah

    2016-01-01

    The purpose of this paper is to present a multi-sensor approach to the detection and inspection of steel bars in reinforced concrete structures. In connection with our past experience related to non-destructive testing of different materials, we propose using two potentially effective methods: active infrared thermography with microwave excitation and the eddy current technique. In this article active infrared thermography with microwave excitation is analyzed both by numerical modeling and experiments. This method, based on thermal imaging, due to its characteriatics should be considered as a preliminary method for the assessment of relatively shallowly located steel bar reinforcements. The eddy current technique, on the other hand, allows for more detailed evaluation and detection of deeply located rebars. In this paper a series of measurement results, together with the initial identification of certain features of steel reinforcement bars will be presented. PMID:26891305

  9. Fission modes of mercury isotopes

    Warda, M; Nazarewicz, W

    2012-01-01

    Recent experiments on beta-delayed fission in the mercury-lead region and the discovery of asymmetric fission in $^{180}$Hg [1] have stimulated renewed interest in the mechanism of fission in heavy nuclei. Here we study fission modes and fusion valleys in $^{180}$Hg and $^{198}$Hg using the self-consistent nuclear density functional theory employing Skyrme and Gogny energy density functionals. We show that the observed transition from asymmetric fission in $^{180}$Hg towards more symmetric distribution of fission fragments in $^{198}$Hg can be explained in terms of competing fission modes of different geometries that are governed by shell effects in pre-scission configurations. The density distributions at scission configurations are studied and related to the experimentally observed mass splits.

  10. Dynamical features of nuclear fission

    Santanu Pal

    2015-08-01

    It is now established that the transition-state theory of nuclear fission due to Bohr and Wheeler underestimates several observables in heavy-ion-induced fusion–fission reactions. Dissipative dynamical models employing either the Langevin equation or equivalently the Fokker–Planck equation have been developed for fission of heavy nuclei at high excitations (T ∼1 MeV or higher). Here, we first present the physical picture underlying the dissipative fission dynamics. We mainly concentrate upon the Kramers’ prescription for including dissipation in fission dynamics. We discuss, in some detail, the results of a statistical model analysis of the pre-scission neutron multiplicity data from the reactions 19F+194,196,198Pt using Kramers’ fission width. We also discuss the multi-dimensional Langevin equation in the context of kinetic energy and mass distribution of the fission fragments.