WorldWideScience

Sample records for permanently shutdown nuclear

  1. Replacement energy, capacity, and reliability costs for permanent nuclear reactor shutdowns

    International Nuclear Information System (INIS)

    VanKuiken, J.C., Buehring, W.A.; Hamilton, S.; Kavicky, J.A.; Cavallo, J.D.; Veselka, T.D.; Willing, D.L.

    1993-10-01

    Average replacement power costs are estimated for potential permanent shutdowns of nuclear electricity-generating units. Replacement power costs are considered to include replacement energy, capacity, and reliability cost components. These estimates were developed to assist the US Nuclear Regulatory Commission in evaluating regulatory issues that potentially affect changes in serious reactor accident frequencies. Cost estimates were derived from long-term production-cost and capacity expansion simulations of pooled utility-system operations. Factors that affect replacement power cost, such as load growth, replacement sources of generation, and capital costs for replacement capacity, were treated in the analysis. Costs are presented for a representative reactor and for selected subcategories of reactors, based on estimates for 112 individual reactors

  2. Nuclear reactor unit shutdown planning

    International Nuclear Information System (INIS)

    Gardais, J.P.

    1994-01-01

    In order to optimize the reactor maintenance shutdown efficiency and the reactor availability, an audit had been performed on the shutdown organization at EDF: management, skills, methods and experience feedback have been evaluated; several improvement paths have been identified: project management, introduction of shutdown management professionals, shutdown permanent industrialization, and experience feedback engineering

  3. Nuclear reactor shutdown system

    International Nuclear Information System (INIS)

    Mangus, J.D.; Cooper, M.H.

    1982-01-01

    An improved nuclear reactor shutdown system is described comprising a temperature sensitive device connected to control the electric power supply to a magnetic latch holding a body of a neutron absorbing material. The temperature sensitive device is exposed to the reactor coolant so that when the reactor coolant temperature rises above a specific level, the temperature sensitive device will cause deenergization of the magnetic latch to allow the body of neutron absorbing material to enter the reactor core. (author)

  4. Preliminary Evaluation of Removing Used Nuclear Fuel from Shutdown Sites

    Energy Technology Data Exchange (ETDEWEB)

    Maheras, Steven J.; Best, Ralph E.; Ross, Steven B.; Buxton, Kenneth A.; England, Jeffery L.; McConnell, Paul E.

    2013-09-30

    This report fulfills the M2 milestone M2FT-13PN0912022, “Stranded Sites De-Inventorying Report.” In January 2013, the U.S. Department of Energy (DOE) issued the Strategy for the Management and Disposal of Used Nuclear Fuel and High-Level Radioactive Waste (DOE 2013). Among the elements contained in this strategy is an initial focus on accepting used nuclear fuel from shutdown reactor sites. This focus is consistent with the recommendations of the Blue Ribbon Commission on America’s Nuclear Future, which identified removal of stranded used nuclear fuel at shutdown sites as a priority so that these sites may be completely decommissioned and put to other beneficial uses (BRC 2012). Shutdown sites are defined as those commercial nuclear power reactor sites where the nuclear power reactors have been shut down and the site has been decommissioned or is undergoing decommissioning. In this report, a preliminary evaluation of removing used nuclear fuel from 12 shutdown sites was conducted. The shutdown sites were Maine Yankee, Yankee Rowe, Connecticut Yankee, Humboldt Bay, Big Rock Point, Rancho Seco, Trojan, La Crosse, Zion, Crystal River, Kewaunee, and San Onofre. These sites have no other operating nuclear power reactors at their sites and have also notified the U.S. Nuclear Regulatory Commission that their reactors have permanently ceased power operations and that nuclear fuel has been permanently removed from their reactor vessels. Shutdown reactors at sites having other operating reactors are not included in this evaluation.

  5. Alternative Shutdown Panel. Amaraz Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Saenz de Santa Maria Valin, J.

    2016-07-01

    Between 2010 and 2014 the Nuclear Power Plant of Almaraz conducted one of the most complex projects in its history: The installation of an Alternative Shutdown Panel with the capability to stop the plant in case of fire in the Control room or in the Cable room. This project represented a great economic and organizational effort for the plant, but at the same time has been a great improvement in the safety of the installation, which was demonstrated by the achievement of a major milestone in the history of Almaraz: The actual shutdown from outside of the Control room. (Author)

  6. Preliminary Evaluation of Removing Used Nuclear Fuel from Shutdown Sites

    Energy Technology Data Exchange (ETDEWEB)

    Maheras, Steven J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Best, Ralph E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ross, Steven B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buxton, Kenneth A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); England, Jeffery L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McConnell, Paul E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Massaro, Lawrence M. [Fermi Research Alliance (FRA), Batavia, IL (United States); Jensen, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-30

    A preliminary evaluation of removing spent nuclear fuel (SNF) from 13 shutdown nuclear power plant sites was performed. At these shutdown sites the nuclear power reactors have been permanently shut down and the sites have been decommissioned or are undergoing decommissioning. The shutdown sites were Maine Yankee, Yankee Rowe, Connecticut Yankee, Humboldt Bay, Big Rock Point, Rancho Seco, Trojan, La Crosse, Zion, Crystal River, Kewaunee, San Onofre, and Vermont Yankee. The evaluation was divided into four components: Characterization of the SNF and greater-than-Class C low-level radioactive waste (GTCC waste) inventory A description of the on-site infrastructure at the shutdown sites An evaluation of the near-site transportation infrastructure and transportation experience at the shutdown sites An evaluation of the actions necessary to prepare for and remove SNF and GTCC waste. The primary sources for the inventory of SNF and GTCC waste were the U.S. Department of Energy (DOE) spent nuclear fuel inventory database, industry publications such as StoreFUEL, and government sources such as the U.S. Nuclear Regulatory Commission. The primary sources for information on the conditions of on-site infrastructure and near-site transportation infrastructure and experience included information collected during site visits, information provided by managers at the shutdown sites, Facility Interface Data Sheets compiled for DOE in 2005, Services Planning Documents prepared for DOE in 1993 and 1994, industry publications such as Radwaste Solutions, and Google Earth. State staff, State Regional Group representatives, a Tribal representative, and a Federal Railroad Administration representative have participated in nine of the shutdown site visits. Every shutdown site was found to have at least one off-site transportation mode option for removing its SNF and GTCC waste; some have multiple options. Experience removing large components during reactor decommissioning provided an

  7. Rodded shutdown system for a nuclear reactor

    International Nuclear Information System (INIS)

    Golden, M.P.; Govi, A.R.

    1978-01-01

    A top mounted nuclear reactor diverse rodded shutdown system utilizing gas fed into a pressure bearing bellows region sealed at the upper extremity to an armature is described. The armature is attached to a neutron absorber assembly by a series of shafts and connecting means. The armature is held in an uppermost position by an electromagnet assembly or by pressurized gas in a second embodiment. Deenergizing the electromagnet assembly, or venting the pressurized gas, causes the armature to fall by the force of gravity, thereby lowering the attached absorber assembly into the reactor core

  8. Industry shutdown rates and permanent layoffs: evidence from firm-worker matched data

    Directory of Open Access Journals (Sweden)

    Kim P. Huynh

    2017-06-01

    Full Text Available Abstract Firm shutdown creates a turbulent situation for workers as it leads directly to layoffs for its workers. An additional consideration is whether a firm’s shutdown within an industry creates turbulence for workers at other continuing firms. Using data drawn from the Longitudinal Worker File, a Canadian firm-worker matched employment database, we investigate the impact of industry shutdown rates on workers at continuing firm. This paper exploits variation in shutdown rates across industries and within an industry over time to explain the rate of permanent layoffs and the growth of workers’ earnings. We find an increase in industry shutdown rates increases the probability of permanent layoffs and decreases earnings growth for workers at continuing firms.

  9. Order concerning a nuclear reactor shutdown

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Judgment of the State Administrative Court of Baden Wuerttemberg in head notes including: The authority of the Minister-President to give general guidelines includes the right to issue single directives; in matters of prime political significance he can take measures to realize such aims. - It is no extraneous consideration for the supervisory board under atomic energy law to point out in an order concerning a nuclear reactor shutdown that the disallowed operation of a nuclear plant conflicts with the obligation of the state to provide protection and constitutes a penal offence. Further a discourse on the assignment of discretionary powers under Paragraph 19 Section 3 Clause 2 No. 3 of the Atomic Energy Law. (HSCH) [de

  10. Preliminary Evaluation of Removing Used Nuclear Fuel from Shutdown Sites

    Energy Technology Data Exchange (ETDEWEB)

    Maheras, Steven J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Best, Ralph E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ross, Steven B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buxton, Kenneth A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); England, Jeffery L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McConnell, Paul E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Massaro, Lawrence M. [Federal Railroad Administration (FRA) (United States); Jensen, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-10-01

    This report presents a preliminary evaluation of removing used nuclear fuel (UNF) from 12 shutdown nuclear power plant sites. At these shutdown sites the nuclear power reactors have been permanently shut down and the sites have been decommissioned or are undergoing decommissioning. The shutdown sites are Maine Yankee, Yankee Rowe, Connecticut Yankee, Humboldt Bay, Big Rock Point, Rancho Seco, Trojan, La Crosse, Zion, Crystal River, Kewaunee, and San Onofre. The evaluation was divided into four components: characterization of the UNF and greater-than-Class C low-level radioactive waste (GTCC waste) inventory; a description of the on-site infrastructure and conditions relevant to transportation of UNF and GTCC waste; an evaluation of the near-site transportation infrastructure and experience relevant to shipping transportation casks containing UNF and GTCC waste, including identification of gaps in information; and, an evaluation of the actions necessary to prepare for and remove UNF and GTCC waste. The primary sources for the inventory of UNF and GTCC waste are the U.S. Department of Energy (DOE) RW-859 used nuclear fuel inventory database, industry sources such as StoreFUEL and SpentFUEL, and government sources such as the U.S. Nuclear Regulatory Commission. The primary sources for information on the conditions of site and near-site transportation infrastructure and experience included observations and information collected during visits to the Maine Yankee, Yankee Rowe, Connecticut Yankee, Humboldt Bay, Big Rock Point, Rancho Seco, Trojan, La Crosse, and Zion sites; information provided by managers at the shutdown sites; Facility Interface Data Sheets compiled for DOE in 2005; Services Planning Documents prepared for DOE in 1993 and 1994; industry publications such as Radwaste Solutions; and Google Earth. State and Regional Group representatives, a Tribal representative, and a Federal Railroad Administration representative participated in six of the shutdown site

  11. Preliminary Evaluation of Removing Used Nuclear Fuel from Shutdown Sites

    Energy Technology Data Exchange (ETDEWEB)

    Maheras, Steven J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Best, Ralph E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ross, Steven B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buxton, Kenneth A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); England, Jeffery L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McConnell, Paul E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Massaro, Lawrence M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jensen, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-09-30

    A preliminary evaluation of removing spent nuclear fuel (SNF) from 13 shutdown nuclear power reactor sites was conducted. At these shutdown sites the nuclear power reactors have been permanently shut down and the sites have been decommissioned or are undergoing decommissioning. The shutdown sites were Maine Yankee, Yankee Rowe, Connecticut Yankee, Humboldt Bay, Big Rock Point, Rancho Seco, Trojan, La Crosse, Zion, Crystal River, Kewaunee, San Onofre, and Vermont Yankee. The evaluation was divided into four components: (1) characterization of the SNF and greater-than-Class C low-level radioactive waste (GTCC waste) inventory, (2) a description of the on-site infrastructure and conditions relevant to transportation of SNF and GTCC waste, (3) an evaluation of the near-site transportation infrastructure and experience relevant to shipping transportation casks containing SNF and GTCC waste, including identification of gaps in information, and (4) an evaluation of the actions necessary to prepare for and remove SNF and GTCC waste. Every site was found to have at least one off-site transportation mode option for removing its SNF and GTCC waste; some have multiple options. Experience removing large components during reactor decommissioning provided an important source of information used to identify the transportation mode options for the sites. Especially important in conducting the evaluation were site visits, through which information was obtained that would not have been available otherwise. Extensive photographs taken during the site visits proved to be particularly useful in documenting the current conditions at or near the sites. It is expected that additional site visits will be conducted to add to the information presented in the evaluation.

  12. Nuclear reactor shutdown control rod assembly

    International Nuclear Information System (INIS)

    Bilibin, K.

    1988-01-01

    This patent describes a nuclear reactor having a reactor core and a reactor coolant flowing therethrough, a temperature responsive, self-actuated nuclear reactor shutdown control rod assembly, comprising: an upper drive line terminating at its lower end with a substantially cylindrical wall member having inner and outer surfaces; a lower drive line having a lower end adapted to be attached to a neutron absorber; a ring movable disposed about the outer surface of the wall member of the upper drive line; thermal actuation means adapted to be in heat exchange relationship with coolant in an associated reactor core and in contact with the ring, and balls located within the openings in the upper drive line. When reactor coolant approaches a predetermined design temperature the actuation means moves the ring sufficiently so that the balls move radially out from the recess and into the space formed by the second portion of the ring thereby removing the vertical support for the lower drive line such that the lower drive line moves downwardly and inserts an associated neutron absorber into an associated reactor core resulting in automatic reduction of reactor power

  13. Safety and regulation aspects of nuclear facilities shutdown

    International Nuclear Information System (INIS)

    Clement, B.

    1977-01-01

    Technical dispositions that safety authorities will accept after shutdown of a nuclear installation and reglementation to use are examined. The different solutions from surveillance and maintenance, after removal of fissile materials and radioactive fluids, to dismantling are discussed especially for reactors. In each case the best solution has to be studied to ensure protection of public health and environment [fr

  14. Method of disposing of shut-down nuclear power plants

    International Nuclear Information System (INIS)

    Gaiser, H.

    1984-01-01

    A shut-down atomic power plant or a section thereof, particularly the nuclear reactor, is disposed of by sinking it to below ground level by constructing a caisson with cutting edges from the foundations of said plant or section or by excavating a pit therebelow

  15. Evaluation of reactivity shutdown margin for nuclear fuel reload optimization

    International Nuclear Information System (INIS)

    Wong, Hing-Ip; Maldonado, G.I.

    1995-01-01

    The FORMOSA-P code is a nuclear fuel management optimization package that combines simulated annealing (SA) and nodal generalized perturbation theory (GPT). Recent studies at Electricite de France (EdF-Clamart) have produced good results for power-peaking minimizations under multiple limiting control rod configurations. However, since the reactivity shutdown margin is not explicitly treated as an objective or constraint function, then any optimal loading patterns (LPs) are not guaranteed to yield an adequate shutdown margin (SDM). This study describes the implementation of the SDM calculation within a FORMOSA-P optimization. Maintaining all additional computational requirements to a minimum was a key consideration

  16. Evaluation of reactivity shutdown margin for nuclear fuel reload optimization

    International Nuclear Information System (INIS)

    Engrand, P.; Wong, H. I.; Maldonado, G.I.

    1996-01-01

    The FORMOSA-P code is a nuclear fuel management optimization package which combines simulated annealing (SA) and nodal generalized perturbation theory (GPT). Recent studies at Electricite de France have produced good results for power peaking minimizations under multiple limiting control rod configurations. However, since the reactivity shutdown margin is not explicitly treated as an objective or constraint function, then any optimal loading patterns (LPs) are not guaranteed to yield an adequate shutdown margin (SDM). This study describes the implementation of the SDM calculation within a FORMOSA-P optimization. Maintaining all additional computational requirements to a minimum was a key consideration. (authors). 4 refs., 2 figs

  17. Fluid shut-down system for a nuclear reactor

    International Nuclear Information System (INIS)

    Barclay, F.W.; Frey, J.R.; Wilson, J.N.; Besant, R.W.

    1975-01-01

    A nuclear reactor shut-down system is described which comprises a fluidic vortex valve for releasably maintaining a liquid neutron poison outside of the reactor core, the poison being contained by a reservoir and biased by pressure for flow into poison tubes within the reactor. The upper ends of the poison tubes communicate with the supply port of the vortex valve. A continuous gas flow into the control port maintains normal controlled operation. Shut-down is effected by interruption of the control input. One embodiment comprises three groups of poison tubes and one vortex valve associated with each group wherein shut-down is effected by poison release in two out of the three groups. Preferably, each vortex valve comprises three control ports which operate on a ''voting'' or two-out-of-three basis. (Official Gazette)

  18. Reactor shutdown: nuclear power plant performance

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The article essentially looks at the performance of nine of Sweden's nuclear reactors. A table lists the percentage of time for the first three quarters of 1981 that the reactors were operating, and the number of hours out of service for planned or other reasons. In particular, one station - Ringhals 3 - was out of action because of a damaged tube in the associated steam generator. The same fault occurred with another reactor - Ringhals 4 - before this was brought into service. The reasons for the failure and its importance are briefly discussed. (G.P.)

  19. Loss of benefits resulting from mandated nuclear plant shutdowns

    International Nuclear Information System (INIS)

    Peerenboom, J.P.; Buehring, W.A.

    1982-01-01

    This paper identifies and discusses some of the important consequences of nuclear power plant unavailability, and quantifies a number of technical measures of loss of benefits that result from regulatory actions such as licensing delays and mandated nuclear plant outages. The loss of benefits that accompany such regulatory actions include increased costs of systems generation, increased demand for nonnuclear and often scarce fuels, and reduced system reliability. This paper is based on a series of case studies, supplemented by sensitivity studies, on hypothetical nuclear plant shutdowns. These studies were developed by Argonne in cooperation with four electric utilities

  20. Changing nuclear plant operating limits during startup and shutdown

    International Nuclear Information System (INIS)

    Arnold, E.C.; Carlson, R.W.; Ray, N.K.; Roarty, D.H.

    1990-01-01

    During startup and shutdown operation of pressurized water reactor (PWR) nuclear power plants, a low pressure decay heat removal system is used to maintain core cooling. During these phases of operation, there are numerous operating practices and design limits to meet special and sometimes conflicting requirements unique to these operations. This paper evaluates the impact and interdependencies of recent issues on plant operation and design

  1. Preliminary Evaluation of Removing Used Nuclear Fuel From Nine Shutdown Sites

    Energy Technology Data Exchange (ETDEWEB)

    Maheras, Steven J.; Best, Ralph; Ross, Steven B.; Buxton, Kenneth A.; England, Jeffery L.; McConnell, Paul

    2013-04-30

    The Blue Ribbon Commission on America’s Nuclear Future identified removal of stranded used nuclear fuel at shutdown sites as a priority so that these sites may be completely decommissioned and put to other beneficial uses. In this report, a preliminary evaluation of removing used nuclear fuel from nine shutdown sites was conducted. The shutdown sites included Maine Yankee, Yankee Rowe, Connecticut Yankee, Humboldt Bay, Big Rock Point, Rancho Seco, Trojan, La Crosse, and Zion. At these sites a total of 7649 used nuclear fuel assemblies and a total of 2813.2 metric tons heavy metal (MTHM) of used nuclear fuel are contained in 248 storage canisters. In addition, 11 canisters containing greater-than-Class C (GTCC) low-level radioactive waste are stored at these sites. The evaluation was divided in four components: • characterization of the used nuclear fuel and GTCC low-level radioactive waste inventory at the shutdown sites • an evaluation of the onsite transportation conditions at the shutdown sites • an evaluation of the near-site transportation infrastructure and experience relevant to the shipping of transportation casks containing used nuclear fuel from the shutdown sites • an evaluation of the actions necessary to prepare for and remove used nuclear fuel and GTCC low-level radioactive waste from the shutdown sites. Using these evaluations the authors developed time sequences of activities and time durations for removing the used nuclear fuel and GTCC low-level radioactive waste from a single shutdown site, from three shutdown sites located close to each other, and from all nine shutdown sites.

  2. Site Characterization Report ORGDP Diffusion Facilities Permanent Shutdown K-700 Power House and K-27 Switch Yard/Switch House

    Energy Technology Data Exchange (ETDEWEB)

    Thomas R.J., Blanchard R.D.

    1988-06-13

    The K-700 Power House area, initially built to supply power to the K-25 gaseous diffusion plant was shutdown and disassembled in the 1960s. This shutdown was initiated by TVA supplying economical power to the diffusion plant complex. As a result of world wide over production of enriched, reactor grade U{sup 235}, the K-27 switch yard and switch house area was placed in standby in 1985. Subsequently, as the future production requirements decreased, the cost of production increased and the separation technologies for other processes improved, the facility was permanently shutdown in December, 1987. This Site Characterization Report is a part of the FY-88 engineering Feasibility Study for placing ORGDP Gaseous Diffusion Process facilities in 'Permanent Shutdown'. It is sponsored by the Department of Energy through Virgil Lowery of Headquarters--Enrichment and through Don Cox of ORO--Enrichment Operations. The primary purpose of these building or site characterization reports is to document, quantify, and map the following potential problems: Asbestos; PCB containing fluids; Oils, coolants, and chemicals; and External contamination. With the documented quantification of the concerns (problems) the Engineering Feasibility Study will then proceed with examining the potential solutions. For this study, permanent shutdown is defined as the securing and/or conditioning of each facility to provide 20 years of safe service with minimal expenditures and, where feasible, also serving DOE's needs for long-term warehousing or other such low-risk use. The K-700 power house series of buildings were either masonry construction or a mix of masonry and wood. The power generating equipment was removed and sold as salvage in the mid 1960s but the buildings and auxiliary equipment were left intact. The nine ancillary buildings in the power house area use early in the Manhattan Project for special research projects, were left intact minus the original special equipment

  3. Loss-of-benefits analysis for nuclear power plant shutdowns: methodology and illustrative case study

    International Nuclear Information System (INIS)

    Peerenboom, J.P.; Buehring, W.A.; Guziel, K.A.

    1983-11-01

    A framework for loss-of-benefits analysis and a taxomony for identifying and categorizing the effects of nuclear power plant shutdowns or accidents are presented. The framework consists of three fundamental steps: (1) characterizing the shutdown; (2) identifying benefits lost as a result of the shutdown; and (3) quantifying effects. A decision analysis approach to regulatory decision making is presented that explicitly considers the loss of benefits. A case study of a hypothetical reactor shutdown illustrates one key loss of benefits: net replacement energy costs (i.e., change in production costs). Sensitivity studies investigate the responsiveness of case study results to changes in nuclear capacity factor, load growth, fuel price escalation, and discount rate. The effects of multiple reactor shutdowns on production costs are also described

  4. Reserves for shutdown/dismantling and disposal in nuclear technology. Theses and recommendations on reform options

    International Nuclear Information System (INIS)

    Meyer, Bettina

    2012-01-01

    The study on reserves for shutdown, dismantling and disposal of nuclear facilities covers the following topics: cost for shutdown, dismantling and disposal and amount and transparency of nuclear reserves, solution by y stock regulated by public law for long-term liabilities, and improvement of the protection in the event of insolvency for the remaining EVU reserves for short- and intermediate-term liabilities. The appendix includes estimations and empirical values for the cost of shutdown and dismantling, estimation of disposal costs, and a summary of Swiss studies on dismantling and disposal and transfer to Germany.

  5. PSA for the shutdown mode for nuclear power plants

    International Nuclear Information System (INIS)

    1994-06-01

    The meeting, which was attended by more than 75 participants from 20 countries, provided a broad discussion forum where all the currently active major shutdown PSA programmes were reviewed. The meeting also addressed the issues related to actual performance of shutdown PSA studies as well as insight gained from the studies. This document, which was prepared during the TCM, contains the results of extensive discussions which were held in specific working groups. The papers presented at the meeting provide a comprehensive overview of the state of the art of shutdown risk assessment and remedial measures taken to reduce the risk in outages. It is hoped that this document will be very useful to all individuals with interest in increasing safety during outages at NPPs. Refs, figs and tabs

  6. Primary shutdown system monitoring unit for nuclear power plants

    International Nuclear Information System (INIS)

    Khan, Tahir Kamal; Balasubramanian, R.; Agilandaeswari, K.

    2013-01-01

    Shut off rods made up of neutron absorbing material are used as Primary Shutdown System. To reduce the power of the reactor under certain abnormal operating conditions, these rods must go down into the core within a specified time. Any malfunctioning in the movement of rods cannot be tolerated and Secondary Shutdown System (SSS) must be actuated within stipulated time to reduce the reactor power. A special safety critical, hardwired electronics unit has been designed to detect failure of PSS Shut off rods movements and generate trip signals for initiating SSS. (author)

  7. SEPRA - shutdown PSA for the OLKILUOTO nuclear power plant

    International Nuclear Information System (INIS)

    Himanen, R.

    1995-01-01

    The utility TVO has extended the PSA study to the analysis of refueling, shutdown and startup. The Shutdown Event PRA (SEPRA) was reported to the authority in September 1992. The study consists of the analysis of leaks and loss of decay heat removal in the planned shutdown conditions. Special studies were performed for the cold pressurization, for local criticality events, for heavy load transport and for the transients during startup and shutdown. A remarkable effort was put to identify risks, i.e. to the qualitative analysis. The regular preventive maintenance tasks in the refueling outages were analyzed and the important tasks were selected for further studies. Besides the severe core damage risk the utility was interested in less grave consequences, e.g. the economic risks, causing significant extension of outages. The plant specific screening of initiators consisted of a study on the incident history and of interviewing the plant personnel on selected tasks. A number of thermohydraulic calculations were carried out to support the analysis of accident sequences. The operator actions after an initiating event were verified with the operating staff. The annual core damage risk from the refueling outage is about one forth of the total annual risk. The modifications decreased significantly the core damage frequency. It is foreseen that the SEPRA will form a basis of the procedure enhancement for the low power states. (author) 5 figs., 1 tab., 10 refs

  8. Probabilistic safety assessments of nuclear power plants for low power and shutdown modes

    International Nuclear Information System (INIS)

    2000-03-01

    Within the past several years the results of nuclear power plant operating experience and performance of probabilistic safety assessments (PSAs) for low power and shutdown operating modes have revealed that the risk from operating modes other than full power may contribute significantly to the overall risk from plant operations. These early results have led to an increased focus on safety during low power and shutdown operating modes and to an increased interest of many plant operators in performing shutdown and low power PSAs. This publication was developed to provide guidance and insights on the performance of PSA for shutdown and low power operating modes. The preparation of this publication was initiated in 1994. Two technical consultants meetings were conducted in 1994 and one in February 1999 in support of the development of this report

  9. Shutdown and low-power operation at commercial nuclear power plants in the United States

    International Nuclear Information System (INIS)

    1993-09-01

    The report contains the results of the NRC Staff's evaluation of shutdown and low-power operations at US commercial nuclear power plants. The report describes studies conducted by the staff in the following areas: Operating experience related to shutdown and low-power operations, probabilistic risk assessment of shutdown and low-power conditions and utility programs for planning and conducting activities during periods the plant is shut down. The report also documents evaluations of a number of technical issues regarding shutdown and low-power operations performed by the staff, including the principal findings and conclusions. Potential new regulatory requirements are discussed, as well as potential changes in NRC programs. A draft report was issued for comment in February 1992. This report is the final version and includes the responses to the comments along with the staff regulatory analysis of potential new requirements

  10. Optimal test intervals for shutdown systems for the Cernavoda nuclear power station

    International Nuclear Information System (INIS)

    Negut, Gh.; Laslau, F.

    1993-01-01

    Cernavoda nuclear power station required a complete PSA study. As a part of this study, an important goal to enhance the effectiveness of the plant operation is to establish optimal test intervals for the important engineering safety systems. The paper presents, briefly, the current methods to optimize the test intervals. For this reason it was used Vesely methods to establish optimal test intervals and Frantic code to survey the influence of the test intervals on system availability. The applications were done on the Shutdown System no. 1, a shutdown system provided whit solid rods and on Shutdown System no. 2 provided with injecting poison. The shutdown systems receive nine total independent scram signals that dictate the test interval. Fault trees for the both safety systems were developed. For the fault tree solutions an original code developed in our Institute was used. The results, intended to be implemented in the technical specifications for test and operation of Cernavoda NPS are presented

  11. Management of refuelling, modifications and accidental shut-down of nuclear power plant

    International Nuclear Information System (INIS)

    1996-01-01

    This document is the appendix of HAF 0300 (91) 'Code on the Safety of Nuclear Power Plant Operation', which was promulgated by the National Nuclear Safety Administration (NNSA) on March 2, 1994, and has the same legal effect. This appendix is applicable to establish the administrative management procedures for refuelling, modifications and accidental shut-down in the period of operation of pressurized water thermal neutron reactor of nuclear power plants. The NNSA shall be responsible for interpretation of this document

  12. Tricon hardware controller implementation of CANDU nuclear power plant shutdown system

    International Nuclear Information System (INIS)

    Zahedi, P.

    2007-01-01

    This paper introduces the implementation of logic functions associated with the shutdown systems of CANDU nuclear power plants. The experimental aspects of this work include development of control program embedded in shutdown systems of CANDU based NPPs. A physical test environment is designed to simulate the measurements of in-core flux detector (ICFD) and ion chamber (I/C) signals. The programmable logic used in this experimentation provides Triple Modular Redundant (TMR) architecture as well as a voting mechanism used upon execution of control program on each independent channel. (author)

  13. Reload shutdown for Nuclear Power Stations in spain in 2003

    International Nuclear Information System (INIS)

    2004-01-01

    Regarding time reductions in fuel reloading at Spanish nuclear power stations, the Spanish Nuclear Security Council (CSN), at the request of the Spanish Finance and Treasury Department of the Chamber of Deputies, delivered an instruction, by which power station's owners were urged to establish a detailed planning of reload operations. This article includes the results of this instruction. (Author) 6 refs

  14. Medical surveillance of nuclear power plant workers during reactor shutdown using whole-body counting and excretion analysis

    International Nuclear Information System (INIS)

    Le Roux-Desmis, C.

    1987-01-01

    After a review of radioactivity basis and radiation protection principles, the various aspects of medical surveillance of nuclear power plant workers during reactor shutdown, are presented. Internal contamination incidents that happened during 1986-1987 shutdown of Paluel reactor are exposed. Internal contamination levels are evaluated using whole-body counting and radionuclide determination in feces and urine and compared with dose limits [fr

  15. Electricity-market price and nuclear power plant shutdown: Evidence from California

    International Nuclear Information System (INIS)

    Woo, C.K.; Ho, T.; Zarnikau, J.; Olson, A.; Jones, R.; Chait, M.; Horowitz, I.; Wang, J.

    2014-01-01

    Japan's Fukushima nuclear disaster, triggered by the March 11, 2011 earthquake, has led to calls for shutting down existing nuclear plants. To maintain resource adequacy for a grid's reliable operation, one option is to expand conventional generation, whose marginal unit is typically fueled by natural-gas. Two timely and relevant questions thus arise for a deregulated wholesale electricity market: (1) what is the likely price increase due to a nuclear plant shutdown? and (2) what can be done to mitigate the price increase? To answer these questions, we perform a regression analysis of a large sample of hourly real-time electricity-market price data from the California Independent System Operator (CAISO) for the 33-month sample period of April 2010–December 2012. Our analysis indicates that the 2013 shutdown of the state's San Onofre plant raised the CAISO real-time hourly market prices by $6/MWH to $9/MWH, and that the price increases could have been offset by a combination of demand reduction, increasing solar generation, and increasing wind generation. - Highlights: • Japan's disaster led to calls for shutting down existing nuclear plants. • We perform a regression analysis of California's real-time electricity-market prices. • We estimate that the San Onofre plant shutdown has raised the market prices by $6/MWH to $9/MWH. • The price increases could be offset by demand reduction and renewable generation increase

  16. Management of individual and collective dosimetry at Fessenheim nuclear plant. Evaluation after refueling shutdown

    International Nuclear Information System (INIS)

    Lamarre, D.; Waller, A.

    1980-01-01

    The principle of dosimetry management chosen by Fessenheim nuclear power station was originally consisted of two phases: - an automatic acquisition of individual doses realized by stylodosimeter readers; - a deferred data processing by computer. The whole system has not been used during the shutdown for the first refuelling of unit number one in view of encountered difficulties with perfecting of automatic readers prototype, this last phase has been replaced by a manual acquisition of doses. The dosimetry data processing has two main objects: - supervision of individual dosimetry for people who work in the nuclear power station; - knowledge of doses assigned for each working and equipment. Moreover, a first dosimetric result of the shutdown for refuelling of unit number one, enables to notice the workings which doses are the most important and written in percentage of total doses: regulatory controls: about 19%; - steam generators working: 16%; - working decontamination and making health physics screen (lock chamber) 10% [fr

  17. Shutdown reactivity meter system for nuclear fuel storage cells

    International Nuclear Information System (INIS)

    Schultz, M.A.

    1981-01-01

    A system for determining whether a self-sustaining neutron chain reaction (I.E., criticality) may occur as each successive nuclear fuel element is added to a liquid-filled tank. This is accomplished by determining whether a multiplication factor, k, approaches unity after each element is added to the tank in accordance with the equation: cr ( Alpha s)/(1-k) where: S is the emission rate of the neutron source; alpha is a term that reflects the detector sensitivity as well as the attenuation of the neutron between source and detector and various geometric considerations in the tank; cr is the counting rate from a neutron detector; and K is a multiplication factor of the assembly at any given time for any given element configuration

  18. Decree no. 2005-79 from January 26, 2005, authorizing the Atomic Energy Commission to proceed to the definitive shutdown and dismantling operations of the nuclear facility no.21, named Siloette research reactor, in the Grenoble city territory (Isere)

    International Nuclear Information System (INIS)

    2005-02-01

    On May 26, 2003, the French atomic energy commission (CEA) addressed an authorization demand for the definitive shutdown and dismantling of the Siloette research reactor. After a technical and administrative instruction of this demand by the French nuclear safety authority (ASN), a project of decree has been presented on July 6, 2004 at the permanent section of the inter-ministry commission of basic nuclear facilities. The commission gave its favourable judgment which is the object of this decree. (J.S.)

  19. Decree no. 2005-78 from January 26, 2005, authorizing the Atomic Energy Commission to proceed to the definitive shutdown and dismantling operations of the nuclear facility no.20, named Siloe reactor, in the Grenoble city territory (Isere)

    International Nuclear Information System (INIS)

    2005-02-01

    On March 19, 2003, the French atomic energy commission (CEA) addressed an authorization demand for the definitive shutdown and dismantling of the Siloe reactor. After a technical and administrative instruction of this demand by the French nuclear safety authority (ASN), a project of decree has been presented on July 6, 2004 at the permanent section of the inter-ministry commission of basic nuclear facilities. The commission gave its favourable judgment which is the object of this decree. (J.S.)

  20. Dynamic Response of AP1000 Nuclear Island Due to Safe Shutdown Earthquake Loading

    Directory of Open Access Journals (Sweden)

    Gan Buntara S.

    2017-01-01

    Full Text Available AP1000 is a standard nuclear power plant developed by Westinghouse and its partners by using an advanced passive safety feature. Among the five principle building structures, namely the nuclear island, turbine building, annex building, diesel generator building and radwaste building, the safety of the nuclear island building is the most concerned. This paper investigates the dynamic response of the nuclear island building of the AP1000 plant subjected to safe shutdown earthquake loadings. A finite element model for the building, which is assumed to be built in a hard-rock base, is developed and its dynamic response is computed with the aid of the commercial finite element package ANSYS. The dynamic characteristics, including the natural frequencies, the vibration modes, and the time histories for displacements, velocities, and accelerations of the building are obtained for two typical safe shutdown earthquakes, El Centro and Kobe earthquakes. The dynamic behavior of the building due to the earthquakes and its safety is examined and highlighted.

  1. 78 FR 79709 - Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown...

    Science.gov (United States)

    2013-12-31

    ... NUCLEAR REGULATORY COMMISSION [Docket No. 50-302; NRC-2013-0283] Duke Energy Florida, Inc., Crystal River Unit 3 Nuclear Generating Plant Post-Shutdown Decommissioning Activities Report AGENCY: Nuclear Regulatory Commission (NRC). ACTION: Notice of receipt; availability; public meeting; and request...

  2. Main approaches to choice of decontamination methods in case of nuclear power plant shutdown

    International Nuclear Information System (INIS)

    Tarasov, V.M.; Syrkus, M.N.

    1991-01-01

    Selection criteria for optimal decontamination technology in case of nuclear power plant shutdown are considered. It is shown that technology evaluation from the viewpoint of observance of required precautionary measures is performed during the first stage of operation followed by analysis of process operational characteristics. The next stage relates to risk analysis of equipment, technological process and structure failures. The selection process is followed then according to criteria of decontamination duration, complexity level of control process and availability of qualified personnel, as well as complexity and composition of radioactive waste conditioning. Further follows decontamination technology evaluation from the viewpoint of its impact on personnal health and enviroment. Cost-benefit ratio resulting from introduction of technologies under consideration are determined at the final stage

  3. Fire protection of safe shutdown capability at commercial nuclear power plants

    International Nuclear Information System (INIS)

    Sullivan, K.

    1993-01-01

    The comprehensive industrial safety standards and codes that exist today have evolved from lessons learned through past experience, research results, and improvements in technological capabilities. The current requirements for fire safety features of commercial nuclear power stations operated in the U.S. are a notable example of this practice. Although fire protection has always been an important design requirement, from the aftermath of a serious fire that occurred in 1975 at the Browns Ferry plant, it was learned that the life safety and property protection concerns of the major fire insurance underwriters may not sufficiently encompass nuclear safety issues, particularly with regard to the potential for fire damage to result in the common mode failure of redundant trains of systems, and composites important to the safe shutdown of the reactor. Following its investigations into the Browns Ferry fire, the Nuclear Regulatory Commission (NRC) promulgated guidance documents, which ultimately developed into mandatory regulations, necessary to assure the implementation of a fire protection program that would address nuclear safety concerns. The new criteria that evolved, contain prescriptive design features, as well as personnel and administrative requirements the Commission determined to be necessary to provide a defense-in-depth level of protection against the hazards of fire and its associated effects on safety related equipment. These criteria are primarily contained in Appendix R of Title 10 to the Code of Federal Regulations (10 CFR 50)

  4. Fire protection of safe shutdown capability at commercial nuclear power plants

    International Nuclear Information System (INIS)

    Sullivan, K.

    1993-01-01

    The comprehensive industrial safety standards and codes that exist today have evolved from lessons learned through past experience, research results, and improvements in technological capabilities. The current requirements for fire safety features of commercial nuclear power stations operated in the US are a notable example of this practice. Although fire protection has always been an important design requirement, from the aftermath of a serious fire that occurred in 1975 at the Browns Ferry plant, it was learned that the life safety and property protection concerns of the major fire insurance underwriters may not sufficiently encompass nuclear safety issues, particularly with regard to the potential for fire damage to result in the common mode failure of redundant trains of systems, and components important to the safe shutdown of the reactor. Following its investigations into the Browns Ferry fire, the Nuclear Regulatory Commission (NRC) promulgated guidance documents, which ultimately developed into mandatory regulations, necessary to assure the implementation of a fire protection program that would address nuclear safety concerns. The new criteria that evolved, contain prescriptive design features, as well as personnel and administrative requirements the Commission determined to be necessary to provide a defense-in-depth level of protection against the hazards of fire and its associated effects on safety related equipment. These criteria are primarily contained in Appendix R of Title 10 to the Code of Federal Regulations (10 CFR 50). Since 1983, various members of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) have provided technical assistance to the Nuclear Regulatory Commission (NRC) in support of its evaluations of fire protection features implemented at commercial nuclear power stations operated in the US. This paper presents a discussion of the insights gained by the author during his active participation in this area

  5. A scoping evaluation of severe accidents at Surry and Grand Gulf Nuclear Power Plants resulting from earthquakes during shutdown conditions

    International Nuclear Information System (INIS)

    Budnitz, R.J.; Davis, P.R.

    1991-01-01

    This report explores the likelihood of seismic-initiated core damage accidents during refueling shutdown conditions at two nuclear power plants, Surry Unit I and Grand Gulf Unit 1. The effort is scoping in character, and has been performed primarily to establish if a potential problem exists sufficient to justify a more rigorous and more quantitative evaluation. A summary is presented of the important conclusions that have been reached. The most important conclusion is that the core-damage frequencies for earthquake-initiated accidents during shutdown at both Surry Unit I and Grand Gulf Unit I are found to be low in absolute terms. The reasons for this are that in their ability to respond to earthquakes during shutdowns, the plants both have large seismic capacities, well above their design-basis levels; and also that both sites enjoy among the lowest seismic hazards of any LWR sites in the US

  6. The nuclear deterrence: permanence and changes

    International Nuclear Information System (INIS)

    Debouzy, O.

    2009-01-01

    The author aims to present that the nuclear deterrence, even with some change, remains today always pertinent and useful. He shows how the application modalities changed. He discusses the need of an analysis of the future weapons and their use, of the articulation between the nuclear deterrence and the anti missiles defense and the necessity of a discussion on the enlarged deterrence. (A.L.B.)

  7. PUMA code simulation of recovery power transients after a short shutdown of the Embalse nuclear power plant

    International Nuclear Information System (INIS)

    Villar, Javier; Pomerantz, Marcelo E.

    2003-01-01

    A simulation of recovery power transients after a short shutdown on Embalse nuclear power plant equilibrium core with slightly enriched uranium fuel was performed in order to know the response of the reactor under such conditions. Also, comparison against the same event in a natural uranium core were done. No significant restrictions were found in operating with enriched fuel in the conditions of the analyzed event and in fact, slightly differences arose with natural uranium fuels. (author)

  8. Permanent Disposal of Nuclear Waste in Salt

    Science.gov (United States)

    Hansen, F. D.

    2016-12-01

    Salt formations hold promise for eternal removal of nuclear waste from our biosphere. Germany and the United States have ample salt formations for this purpose, ranging from flat-bedded formations to geologically mature dome structures. Both nations are revisiting nuclear waste disposal options, accompanied by extensive collaboration on applied salt repository research, design, and operation. Salt formations provide isolation while geotechnical barriers reestablish impermeability after waste is placed in the geology. Between excavation and closure, physical, mechanical, thermal, chemical, and hydrological processes ensue. Salt response over a range of stress and temperature has been characterized for decades. Research practices employ refined test techniques and controls, which improve parameter assessment for features of the constitutive models. Extraordinary computational capabilities require exacting understanding of laboratory measurements and objective interpretation of modeling results. A repository for heat-generative nuclear waste provides an engineering challenge beyond common experience. Long-term evolution of the underground setting is precluded from direct observation or measurement. Therefore, analogues and modeling predictions are necessary to establish enduring safety functions. A strong case for granular salt reconsolidation and a focused research agenda support salt repository concepts that include safety-by-design. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Author: F. D. Hansen, Sandia National Laboratories

  9. The application of knowledge management and TRIZ for solving the safe shutdown capability of fire alarms in nuclear power plants

    International Nuclear Information System (INIS)

    Wang, Chia-Nan; Chen, Hsin-Po; Hsueh, Ming-Hsien; Chin, Fong-Li

    2017-01-01

    The Fukushima nuclear disaster in 2011 has raised widespread concern over the safety of nuclear power plants. This study employed knowledge management in conjunction with the Teoriya Resheniya Izobreatatelskih Zadatch (TRIZ) method in the formulation of a database to facilitate the evaluation of post-fire safe shutdown capability with the aim of safeguarding nuclear facilities in the event of fire. The proposed approach is meant to bring facilities in line with US Nuclear Regulatory Commission (NRC) standards. When implemented in a case study of an Asian nuclear power plant, our method proved highly effective in the detection of 22 cables that fell short of regulatory requirements, thereby reducing 850,000 paths to 0. This study could serve as reference for industry and academia in the development of systematic approaches to the upgrading of nuclear power plants.

  10. The application of knowledge management and TRIZ for solving the safe shutdown capability of fire alarms in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chia-Nan; Chen, Hsin-Po; Hsueh, Ming-Hsien; Chin, Fong-Li [National Kaohsiung Univ. of Applied Sciences, Kaohsiung City, Taiwan (China). Dept. of Industrial Engineering and Management

    2017-11-15

    The Fukushima nuclear disaster in 2011 has raised widespread concern over the safety of nuclear power plants. This study employed knowledge management in conjunction with the Teoriya Resheniya Izobreatatelskih Zadatch (TRIZ) method in the formulation of a database to facilitate the evaluation of post-fire safe shutdown capability with the aim of safeguarding nuclear facilities in the event of fire. The proposed approach is meant to bring facilities in line with US Nuclear Regulatory Commission (NRC) standards. When implemented in a case study of an Asian nuclear power plant, our method proved highly effective in the detection of 22 cables that fell short of regulatory requirements, thereby reducing 850,000 paths to 0. This study could serve as reference for industry and academia in the development of systematic approaches to the upgrading of nuclear power plants.

  11. On the principles of the determination of the safe shut-down earthquake for nuclear power plants in Austria

    International Nuclear Information System (INIS)

    Drimmel, J.

    1976-01-01

    At present no legal guide lines exist in Austria for the determination of the Safe Shut-Down Earthquake. According to experience, the present requirements for a nuclear power plant site are the following: It must be free of marked tectonic faults and it must never have been situated within the epicentral region of a strong earthquake. The maximum expected earthquake and the Safe Shut-Down Earthquake respectively, are fixed by the aid of a frequency map of strong earthquakes and a map of extreme earthquake intensities in Austria based on macroseismic data since 1201 A.D. The corresponding values of acceleration will be prescribed according to the state of science, but must at least be 0.10 g for the horizontal and 0.05 g for the vertical component of acceleration at the basement

  12. On the speed of response of an FPGA-based shutdown system in CANDU nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    She Jingke, E-mail: jshe2@uwo.ca [Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario, N6A 5B9 (Canada); Jiang Jin, E-mail: jjiang@eng.uwo.ca [Department of Electrical and Computer Engineering, The University of Western Ontario, London, Ontario, N6A 5B9 (Canada)

    2011-06-15

    Highlights: > Design and implementation of an FPGA-based CANDU SDS1. > Hardware-in-the-loop simulation for performance evaluation involved with an NPP simulator. > Comparison of the response time between FPGA-based trip channel and software-based PLC. - Abstract: Several issues in an FPGA based implementation of shutdown systems in CANDU nuclear power plants have been investigated in this paper. A particular attention is on the response time of an FPGA implementation of safety shutdown systems in comparison with operating system based software solutions as in existing CANDU plants. The trip decision logic under 'steam generator (SG) level low' condition has been examined in detail. The design and implementation of this logic on an FPGA platform have been carried out. The functionality tests are performed in a hardware-in-the-loop (HIL) environment by connecting the FPGA based system to an NPP simulator, and replacing one channel of Shutdown System Number 1 (SDS1) in the simulator by the FPGA implementation. The response time of the designed system is also measured through multiple tests under different conditions, and statistical data analysis has been performed. The results of the response time tests are compared against those of a software-based implementation of the same trip logic.

  13. Analysis of shutdown and aftercooling cycles of the A-1 nuclear power plant

    International Nuclear Information System (INIS)

    Mueller, V.; Vopatril, M.

    1977-01-01

    A new concept is described of the emergency shut-down and after-cooling of the A-1 reactor based on the elimination of pressure shock and minimization of thermal shock. After-cooling is effected by all circulators which had not been defective before shut-down. During shut-down the pumps run at reduced speed. A diesel generator is used as a self-contained power supply. The after-cooling is classified into three types depending on the machinery power consumption, i.e., normal, emergency and super-emergency. The selection of the power supply and the after-cooling conditions proceeds automatically. A mathematical model is described of A-1 reactor behaviour during different accidents requiring the shut-down and after-cooling. Computer programmes are briefly indicated for the analysis of transients in the primary coolant circuit (ZVJE-73-23, SHOCK A-1), for the analysis of transients resulting from a neutron power controller failure or from a circulator failure (HAZARD), for the analysis of after-cooling processes (DENDEL), and programme SAULIS as an auxiliary programme for processing the results and for the print-out of the DENDEL programme. Steady-state parameters before the failure were found as initial conditions for the calculation of transients. The mathematical model was solved using a system of three computer programmes linked by interprogramme communication. The analysis is described of the cooperation of reactor safety circuits and of the automatic equipment for the reduction of thermal shock in the primary coolant circuit, as is the analysis of reactor accidents related to reactor control and to the safety circuits. Theoretical results are compared with experimental values obtained during the experimental A-1 reactor shut-down and after-cooling. The accuracy of the calculated value for the cooling gas temperature at the central and marginal channel outputs is -10 to +15% during the first 30 s of after-cooling. (J.P.)

  14. Facing the nuclear power phaseout - Swedish experiences of enterprise shutdown and organisational development

    International Nuclear Information System (INIS)

    Lundqvist, K.

    1998-02-01

    The aim of this study is to make an overview of problems and experiences connected to decommissioning and organisational changes of Swedish enterprises and public agencies from a safety perspective. The central point is the view of decommissioning of nuclear power plants as a process of change. In practice decommissioning includes both downsizing and organisational development. The question is which problems can arise and which strategy of change is most adequate from the standpoint of safety. The report starts with a summary of the most important experiences of the process of decommissioning of enterprises during the sixties to eighties concerning the consequences for the individuals and the labour market. After that follows the main results from earlier investigations of shut-down of nuclear power plants regarding the staff. The restructuring and downsizing of the public sector during the nineties have given rise to a large amount of material on staffing issues. The knowledge and experiences drawn from the organisational change processes of Swedish working life during the nineties are then summarised. At last some conclusions for decommissioning of nuclear power plants are discussed. The period before and after the termination of power generation is connected with great strain. The vulnerability of the staff increases and the faith in management can easily be destroyed, which can affect safety and the decommissioning work. The feeling of security increases if the staff continuously is kept informed and within certain limits can influence the course of events. A learning strategy is preferable in comparison to an expert oriented strategy because it is impossible to gain complete control over the technically and socially complex process of decommissioning. Instead of detailed and central planning of the process it will be safer to work in a participative way and to include all the staff in the preparations from the very beginning. By a learning way of working is

  15. Program of social protection for Chornobyl nuclear power plant staff and Slavutich town residents in the aftermath of the plant shutdown

    International Nuclear Information System (INIS)

    Komarov, V.A.

    2001-01-01

    In order to solve social issues related to ChNPP shutdown, the Ukrainian Government approved 'Program of Social Protection for Chornobyl Nuclear Power Plant Staff and Slavutich Town Residents in Aftermath of Plant Shutdown' on 29 November 2000. The Program Objective is to ensure social protection and support of well being of ChNPP staff and Slavutich town residents after the plant shutdown. Preserve and develop town infrastructure. Create compensatory jobs; efficiently manage human resources; provide social allowances and guarantees to the ChNPP staff that is being released, and Slavutich town residents

  16. Corrosion product behaviour in the Loviisa nuclear power plant primary coolant: measures taken to lower radiation levels by modified shutdown procedures

    International Nuclear Information System (INIS)

    Jaernstroem, R.T.

    1983-01-01

    The primary circuit chemistry of the Loviisa nuclear power plant differs in some respects from the concepts commonly used in PWRs. In general, Loviisa 1, which is now in its sixth cycle, and Loviisa 2, which is in its second refuelling and maintenance shutdown (October 1982), are very clean compared with several other PWRs and it seems to be possible to keep the radiation levels low and even reduce them by using correct chemistry during operation; the shutdown conditions seem to have great influence on this matter. These modified shutdown conditions and their influence on radiation levels, dose rates and radwaste buildup are discussed. (author)

  17. Concepts in developing technical means of accident shutdown of nuclear reactor

    International Nuclear Information System (INIS)

    Ionajtis, R.R.; Mikhajlov, M.P.; Cherkashov, Yu.M.

    1992-01-01

    Logic for realization of multistage (echelon) reactor accident shutdown system (ASS) is proposed on the basis of general safety concepts (OPB-88). ASS includes the basis stage with traditional composition of member systems (executive, control, providing ones), auxiliary (doubling) on the other principle of action and insuring (with direct action). Structural schemes of the system as a whole and member subsystems are presented. Recommendations on developing executive and control subsystems are given

  18. Time Delay for the Initiation of an Emergency Shutdown at the Peruvian Nuclear Reactor RP-10

    International Nuclear Information System (INIS)

    Ramon, A.; Ovalle, E.; Canaza, D.; Salazar, A.; Zapata, A.; Felix, J.; Arrieta, R.; Vela, M.

    2008-01-01

    In this paper we show the measurement of the time delay for the initiation of an emergency shutdown state at the RP-10 Reactor. This time delay is the one corresponding to the delay between the detection of a signal of any fixed limit and the start of a protective action to get the reactor in a safety state. The experimental method used is based on monitoring two signals in an oscilloscope, one signal is the elected initiate event and the other is the de-energizing of electromagnets of the security bars. The time delay for each safety and control rods, was measured for seven energizing current values in a range of 36 - 52 mA. The results showed that the minimum value is (84 ± 1.26) ms and the maximum is (108 ± 1.60) ms. In all cases it is noted that, the delay time is less than the limit values prefixed down in the reactor safety report. (authors)

  19. Simulation of Darlington shutdown and regulation systems

    International Nuclear Information System (INIS)

    1986-10-01

    This report describes the development of a simulation of the Darlington Nuclear Generating Station shutdown and regulating systems, DARSIM. The DARSIM program simulates the spatial neutron dynamics, the regulation of the reactor power, and Shutdown System 1, SDS1, and Shutdown System 2, SDS2, software. The DARSIM program operates in the interactive simulation (INSIM) program environment

  20. Analysis of Gamma Dose Rate Caused by Corrosion Products inside the Containment Building of Yonngwang Nuclear Power Plant Unit 3 During Shutdown Period

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Wi Ho; Kim, Jae Cheon; Kim, Soon Young; Kim, Jong Kyung [Hanyang Univ., Seoul (Korea, Republic of)

    2005-07-01

    Occupational radiation exposure(ORE) of nuclear power plant(NPP) workers mainly occurs during the shutdown period. Major radioactive sources are the corrosion products released from the reactor coolant system(RCS). The corrosion products consist of circulating crud and deposited crud. Major radioactive corrosion products, {sup 58}Co and {sup 60}Co, are known to contribute approximately more than 70% of the total ORE. In this study, the corrosion products regarding cobalt were evaluated during the shutdown period, and gamma dose rates caused by them were calculated at the main working area inside the containment building of the Yonggwang NPP Unit 3.

  1. IAEA Director General expresses satisfaction with shutdown of Chernobyl nuclear power plant

    International Nuclear Information System (INIS)

    2000-01-01

    Full text: The Director General of the International Atomic Energy Agency (IAEA), Mohamed ElBaradei, today expressed his satisfaction with the decision of the Government of Ukraine to close the Chernobyl nuclear power plant on 15 December in response to concerns about the safety of the plant. He said he very much appreciated the Ukrainian Government's commitment to maintain high levels of safety at nuclear facilities in Ukraine, which he described as being in line with the high international priority attached to the safety of nuclear facilities. The Director General noted that the year 2001 will mark the 15th anniversary of the nuclear accident in unit 4 at Chernobyl, which had a significant impact on life, health and the environment in Ukraine, Belarus and the Russian Federation and prompted concerns in other countries about the effects of radiation. Since the Chernobyl accident the Agency has assisted, and will continue to assist, Ukraine and the other affected countries, in overcoming the consequences of the accident and enhancing the safe and reliable operation of other nuclear power plants. In the case of Ukraine, the Director General said the Agency intends to assist in the development of an integrated approach to planning, management, and implementation of the decommissioning of units 1 to 3 of the Chernobyl plant as well as in the management of radioactive waste at the plant. More generally, the IAEA is helping Ukraine to strengthen the effectiveness of its nuclear regulatory regime. Since the accident at Chernobyl the IAEA has significantly expanded its nuclear safety programme. It has facilitated the negotiation of a convention on the safety of nuclear installations and other international agreements in the areas of notification and assistance in the case of nuclear accidents, liability and waste management. It has expanded the corpus of international safety standards and put into place an enhanced system of safety review missions to Member States. The

  2. Effects of nuclear power plant shutdowns on electricity consumption and greenhouse gas emissions after the Tohoku Earthquake

    International Nuclear Information System (INIS)

    Cho, Seong-Hoon; Tanaka, Katsuya; Wu, Junjie; Robert, Roland K.; Kim, Taeyoung

    2016-01-01

    This study analyzes how the substitution of fossil fuels for nuclear power due to the shutdown of nuclear power plants after the Tohoku Earthquake affects electricity consumption and greenhouse gas emissions in Japan. Results indicate that Japan generated 4.3 million metric tons (or 0.3%, with a 95% confidence interval) of additional CO_2 emissions in 2011 following the earthquake. The increase in CO_2 emissions stemmed from the combined effects of decreased electricity consumption due to energy conservation efforts and the substitution of fossil fuels for nuclear power following the Tohoku Earthquake. Results also show considerable spatial variation in the impacts of the earthquake on net CO_2 emissions. A majority of the prefectures (40 of 47 prefectures, or 85%) were predicted to experience higher CO_2 emissions after the Tohoku Earthquake while the remaining (7 prefectures) were predicted to experience lower CO_2 emissions. Our findings suggest that Japan and countries under similar risks may want to reformulate energy policy by emphasizing utilization of diverse power and energy sources, including more renewable energy production and electricity conservation. The policy reform should also consider spatial variation in the combined effects of reduced reliance on nuclear power and increased CO_2 conversion factors. - Highlights: • Analyzed effects of Tohoku Earthquake on greenhouse gas emissions in Japan. • Estimated effects on reduced electricity consumption and increased fossil fuel use. • Generated 4.3 million metric tons (or 0.3%) of additional CO_2 emissions in 2011. • Showed spatial variation in the impacts of the earthquake on CO_2 emissions.

  3. Shutdown and degradation: Space computers for nuclear application, verification of radiation hardness. Final report

    International Nuclear Information System (INIS)

    Eichhorn, E.; Gerber, V.; Schreyer, P.

    1995-01-01

    (1) Employment of those radiation hard electronics which are already known in military and space applications. (2) The experience in space-flight shall be used to investigate nuclear technology areas, for example, by using space electronics to prove the range of applications in nuclear radiating environments. (3) Reproduction of a computer developed for telecommunication satellites; proof of radiation hardness by radiation tests. (4) At 328 Krad (Si) first failure of radiation tolerant devices with 100 Krad (Si) hardness guaranteed. (5) Using radiation hard devices of the same type you can expect applications at doses of greater than 1 Mrad (Si). Electronic systems applicable for radiation categories D, C and lower part of B for manipulators, vehicles, underwater robotics. (orig.) [de

  4. Experience in ultrasonic gap measurement between calandria tubes and liquid injection shutdown systems nozzles in Bruce Nuclear Generating Station

    International Nuclear Information System (INIS)

    Abucay, R.C.; Mahil, K.S.; Goszczynski, J.J.

    1995-01-01

    The gaps between calandria tubes (CT) and Liquid Injection Shutdown System (LISS) nozzles at the Bruce Nuclear Generating Station ''A'' (Bruce A) are known to decrease with time due to radiation induced creep/sag of the calandria tubes. If this gap decreases to a point where the calandria tubes come into contact with the LISS nozzle, the calandria tubes could fail as a result of fretting damage. Proximity measurements were needed to verify the analytical models and ensure that CT/LISS nozzle contact does not occur earlier than predicted. The technique used was originally developed at Ontario Hydro Technologies (formerly Ontario Hydro Research Division) in the late seventies and put into practical use by Research and Productivity Council (RPC) of New Brunswick, who carried out similar measurements at Point Lepreau NGS in 1989 and 1991. The gap measurement was accomplished y inserting an inspection probe, containing four ultrasonic transducers (2 to measure gaps and 2 to check for probe tilt) and a Fredericks electrolytic potentiometer as a probe rotational sensor, inside LISS Nozzle number-sign 7. The ultrasonic measurements were fed to a system computer that was programmed to convert the readings into fully compensated gaps, taking into account moderator heavy water temperature and probe tilt. Since the measured gaps were found to be generally larger than predicted, the time to CT/LISS nozzle contact is now being re-evaluated and the planned LISS nozzle replacement will likely be deferred, resulting in considerable savings

  5. Identification of initiating events using a master logic diagram in low-power and shutdown PSA for nuclear power plant

    International Nuclear Information System (INIS)

    Han, S. J.; Park, J. H.; Kim, T. W.; Ha, J. J.

    2003-01-01

    It is necessary to apply a formal technique instead of an empirical technique in the identification of initiating events for Low Power and ShutDown (LPSD) Probabilistic Safety Assessment (PSA) of Nuclear Power Plant (NPP). The present study focuses on the examination of Master Logic Diagram (MLD) technique as a formal technique in the identification of initiating events. The MLD technique is a deductive tool using top-down approach for the formal and logical indentification of initiating events. The present study modified the MLD used in the full power PSA considering the characteristics of LPSD operation. The modified MLD introduced a systematic formation in decomposition process of which the MLD for full power PSA lacked. The modified MLD was able to identify initiating events systematic and logical. However, the formal techniques including the MLD have a limitation for precisely identifying all of the initiating events. In order to overcome this limitation, it is necessary to combine it with an empirical technique. We expect that the modified MLD can be used in an upgrade of the current LPSD PSAs

  6. Development of auxiliary shutdown panel for nuclear training center 2 simulator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheul Un; Lee, Yong Kwan; Cho, Byung Hak; Park, Shin Yeol; Choi, Yong Jae; Kim, Yong Ran [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Kim, Sung Il; Lee, Sung Cheul; Ryuh, Kyung Shin [Korea Electric Power Corp. (KEPCO), Seoul (Korea, Republic of)

    1995-12-31

    The major object of the project is to provide emergency operating conditions to the trainees by adding simulated ASP to the existing NTC(Nuclear Training Center) 2 simulator. The other object of the project is to make KEPRI(Korea Electric Power Research Institute) be equipped with a technical know-how that is inevitable to apply its state-of-art technologies to the existing simulators in KEPCO. The contents of this report are as follows : 1. Design and manufacturing of prototype ASP. 2. Manufacturing and installation of full scope ASP. 3. Development and modification of simulator programs. 4. Integration of hardware and software, perform performance acceptance test (author). 22 refs., 9 figs.

  7. The use of neutron sources in nuclear reactors start-up after long shutdown periods

    International Nuclear Information System (INIS)

    Ponzoni Filho, P.; Borges, J.B.

    1990-01-01

    The reasons for the use of neutron sources in nuclear reactors, the different kinds of sources used and the alternatives to obtain the required minimum neutron counts in the external source range detectors after long maintenance and refueling periods are presented and discussed. The paper presents a formulation based in physics principles and experimental data, to calculate the power and time of reactor operation required to increase the effective fluence of secondary neutron sources. The option of using actinides produced during operation of the reactor as an additional source of neutrons is also discussed in depth to allow similar calculations in other kinds of reactors. The re-utilization of primary sources is considered as a last option. (author)

  8. Radiological impact assessment of the shut-down Salaspils nuclear reactor

    International Nuclear Information System (INIS)

    Riekstina, D.; Berzins, J.; Veveris, O.; Alksnis, J.

    2004-01-01

    The aim of the present work is to gain an overview about the background level of radioactivity and gamma radiation in the 3x3 km area around the Salaspils (Latvia) nuclear reactor after its shutting down. The ultimate design of the project is to assess the impact environmental background level during its 37 years long working time. For this purpose we have carried out: 1) the determination of radioactivity in soils; 2) the determination of radioactivity in groundwater; 3) the measurement of gamma-ray background in the checkpoints. The net density for the collection of soil samples (5 cm thick layer was gathered) and the gamma background measuring was 500x500 m and the total number of checkpoints was 113. The gamma-spectrometric analysis of the groundwater taken from 34 places: in the reactor territory (4-10 m depth) and from the wells of surrounding farms (8-12 m depth) was performed. The soil samples were dried at the temperature 105 0 C until the constant weight, and sifted. The high-resolution gamma spectrometry was used for measurement within the energy range of 50-2000 keV; the time of measuring - 20 hours. The uncertainty of measurements is within a range of 3-10%, but the minimal detectable activity - from 0.3 up to 1 Bq/kg. Cs-137 and natural radionuclides Th-232, U-238, K-40 were detected in soils. The concentration of Cs-137 varies in the range 0.3-227 Bq/kg or 20-1940 Bq/m 2 . It was established that the concentration of Cs-137 in neighbouring checkpoints can differ significantly. It could be explained by the type of soil and the collection place (coniferous or leafy forest, grassland, plough land etc.). The differences of the U-238, Th-232, and K-40 content in samples taken from various places are due to the type of soil and the fertilizers used. The concentration of these radionuclides is significantly lower in the turf. In all water samples the concentration of Cs-137 was lower than the minimal detectable activity. The determined radionuclide

  9. Shutdown and degradation: Optimization of thermal cutting processes for the dismantling of nuclear facilities. Final report

    International Nuclear Information System (INIS)

    Schultz, H.; Hammer, G.; Hampe, A.; Homburg, A.

    1996-01-01

    Cutting processes are required for the dismantling of nuclear facilities which emit only a minimum of contaminated material in the form of shavings, sparks, dust, steam concentrate etc. and equipment which is easy to handle and can be remote controlled. A check of the usual mechanical, thermal and thermo-mechanical cutting procedures showed to what varying extent they are suitable for these tasks. Also the laser beam cutting was able to reduce the material discharge by optimal joints. For the investigation, the plasma cutting and the laser beam cutting were used with the aim of reducing considerably the material discharge by changing the adjust and device setting data for theses cases. The adapting of the speed and the amounts of gas turned out to be effective measures in reducing discharge. Adhesion of metal mass and slag in the joint edge could be achieved with aggressive bearth formation. The expectations made of the project could be fulfilled and process parameters for a pollutant optimised cutting determined. (orig.) [de

  10. The application of knowledge management and TRIZ for solving the safe shutdown capability in case of fire alarms in nuclear power plants

    International Nuclear Information System (INIS)

    Wang, Chia-Nan; Chen, Hsin-Po; Hsueh, Ming-Hsien; Chin, Fong-Li

    2018-01-01

    The Fukushima nuclear disaster in 2011 has raised widespread concern over the safety of nuclear power plants. This study employed knowledge management in conjunction with the Teoriya Resheniya Izobreatatelskih Zadatch (TRIZ) method in the formulation of a database to facilitate the evaluation of post-fire safe shutdown capability with the aim of safeguarding nuclear facilities in the event of fire. The proposed approach is meant to bring facilities in line with US Nuclear Regulatory Commission (NRC) standards. When implemented in a case study of an Asian nuclear power plant, our method proved highly effective in the detection of 22 cables that fell short of regulatory requirements, thereby reducing 850,000 paths to 0. This study could serve as reference for industry and academia in the development of systematic approaches to the upgrading of nuclear power plants.

  11. The application of knowledge management and TRIZ for solving the safe shutdown capability in case of fire alarms in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chia-Nan; Chen, Hsin-Po; Hsueh, Ming-Hsien; Chin, Fong-Li [National Kaohsiung Univ. of Applied Sciences, Kaohsiung City, Taiwan (China). Dept. of Industrial Engineering and Management

    2018-02-15

    The Fukushima nuclear disaster in 2011 has raised widespread concern over the safety of nuclear power plants. This study employed knowledge management in conjunction with the Teoriya Resheniya Izobreatatelskih Zadatch (TRIZ) method in the formulation of a database to facilitate the evaluation of post-fire safe shutdown capability with the aim of safeguarding nuclear facilities in the event of fire. The proposed approach is meant to bring facilities in line with US Nuclear Regulatory Commission (NRC) standards. When implemented in a case study of an Asian nuclear power plant, our method proved highly effective in the detection of 22 cables that fell short of regulatory requirements, thereby reducing 850,000 paths to 0. This study could serve as reference for industry and academia in the development of systematic approaches to the upgrading of nuclear power plants.

  12. Reserves for shutdown/dismantling and disposal in nuclear technology. Theses and recommendations on reform options; Rueckstellungen fuer Stilllegung/Rueckbau und Entsorgung im Atombereich. Thesen und Empfehlungen zu Reformoptionen

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Bettina [Forum Oekologisch-Soziale Marktwirtschaft e.V. (FOeS), Berlin (Germany). Green Budget Germany (GBG)

    2012-04-11

    The study on reserves for shutdown, dismantling and disposal of nuclear facilities covers the following topics: cost for shutdown, dismantling and disposal and amount and transparency of nuclear reserves, solution by y stock regulated by public law for long-term liabilities, and improvement of the protection in the event of insolvency for the remaining EVU reserves for short- and intermediate-term liabilities. The appendix includes estimations and empirical values for the cost of shutdown and dismantling, estimation of disposal costs, and a summary of Swiss studies on dismantling and disposal and transfer to Germany.

  13. Shutdown Safety in NEK

    International Nuclear Information System (INIS)

    Gluhak, Mario; Senegovic, Marko

    2014-01-01

    Industry performance analysis since 2004 has revealed that 23% of the events reported to WANO occurred during outage periods. Given the fact that a plant is in the outage only 5 percent of the time, this emphasizes the importance of shutdown safety and measures station staffs undertake to maintain effective barriers to safety margins during the outage. Back in 1990s, the industry adopted guidance to meet safety requirements by focusing on safety functions. Both WANO and INPO released various documents, reports and guidelines to help accomplish those requirements. However, in the last decade inadequate 'defence in depth' has led to several events affecting shutdown safety and challenging one of the most important nuclear safety principles: 'The special characteristics of nuclear technology are taken into account in all decisions and actions. Reactivity control, continuity of core cooling, and integrity of fission product barriers are valued as essential, distinguishing attributes of nuclear station work environment'. NEK has recognized the importance of 'defence in depth'Industry performance analysis since 2004 has revealed that 23% of the events reported to WANO occurred during outage periods. Given the fact that a plant is in the outage only 5 percent of the time, this emphasizes the importance of shutdown safety and measures station staffs undertake to maintain effective barriers to safety margins during the outage. Back in 1990s, the industry adopted guidance to meet safety requirements by focusing on safety functions. Both WANO and INPO released various documents, reports and guidelines to help accomplish those requirements. However, in the last decade inadequate 'defence in depth' has led to several events affecting shutdown safety and challenging one of the most important nuclear safety principles: 'The special characteristics of nuclear technology are taken into account in all decisions and actions. Reactivity

  14. Behavior of antimony isotopes in the primary coolant of WWER-1000-type nuclear reactors in NPP Kozloduy during operation and shutdown

    International Nuclear Information System (INIS)

    Dobrevski, Ivan D.; Zaharieva, Neli N.; Minkova, Katia F.; Gerchev, Nikolay B.

    2009-01-01

    This paper focuses on the behavior of the antimony isotopes 122 Sb and 124 Sb in the coolant of the WWER reactors in the nuclear power plant Kozloduy (Bulgaria) during operation and shutdown. It is concluded that the chemical properties of their actual precursor, the isotope 121 Sb, determine the behavior of 122 Sb and 124 Sb during operation, load fluctuations, and shutdown as well as during the reactor coolant purification process. It is supposed that differences between the reactor bulk and the core fuel cladding surface chemistry as well as the presence of sub-cooled nucleate boiling at the fuel cladding may create conditions under which a local oxidizing environment may come into existence. (orig.)

  15. Decree no. 2005-78 from January 26, 2005, authorizing the Atomic Energy Commission to proceed to the definitive shutdown and dismantling operations of the nuclear facility no.20, named Siloe reactor, in the Grenoble city territory (Isere); Decret no. 2005-78 du 26 janvier 2005, autorisant le Commissariat a l'energie atomique a proceder aux operations de mise a l'arret definitif et de demantelement de l'installation nucleaire de base no.20 denommee reacteur Siloe sur le territoire de la commune de Grenoble (Isere)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-02-15

    On March 19, 2003, the French atomic energy commission (CEA) addressed an authorization demand for the definitive shutdown and dismantling of the Siloe reactor. After a technical and administrative instruction of this demand by the French nuclear safety authority (ASN), a project of decree has been presented on July 6, 2004 at the permanent section of the inter-ministry commission of basic nuclear facilities. The commission gave its favourable judgment which is the object of this decree. (J.S.)

  16. Decree no. 2005-79 from January 26, 2005, authorizing the Atomic Energy Commission to proceed to the definitive shutdown and dismantling operations of the nuclear facility no.21, named Siloette research reactor, in the Grenoble city territory (Isere); Decret no. 2005-79 du 26 janvier 2005, autorisant le Commissariat a l'Energie Atomique a proceder aux operations de mise a l'arret definitif et de demantelement de l'installation nucleaire de base no.21 denommee reacteur de recherche Siloette sur le territoire de la commune de Grenoble (Isere)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-02-15

    On May 26, 2003, the French atomic energy commission (CEA) addressed an authorization demand for the definitive shutdown and dismantling of the Siloette research reactor. After a technical and administrative instruction of this demand by the French nuclear safety authority (ASN), a project of decree has been presented on July 6, 2004 at the permanent section of the inter-ministry commission of basic nuclear facilities. The commission gave its favourable judgment which is the object of this decree. (J.S.)

  17. The nuclear deterrence: permanence and changes; La dissuasion nucleaire: permanence et changements

    Energy Technology Data Exchange (ETDEWEB)

    Debouzy, O. [August and Debouzy, 75 - Paris (France)

    2009-10-15

    The author aims to present that the nuclear deterrence, even with some change, remains today always pertinent and useful. He shows how the application modalities changed. He discusses the need of an analysis of the future weapons and their use, of the articulation between the nuclear deterrence and the anti missiles defense and the necessity of a discussion on the enlarged deterrence. (A.L.B.)

  18. The Impact of Severe Nuclear Accidents on National Decision for Nuclear Decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Young A; Hornibrook, Carol; Yim, Man Sung [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    Many researchers have tried to identify the impact of severe nuclear accidents on a country's or international nuclear energy policy [2-3]. However, there is little research on the influence of nuclear accidents and historical events on a country's decision to permanently shutdown an NPP versus international nuclear decommissioning trends. To demonstrate the correlation between a nuclear severe accident and the impact on world nuclear decommissioning, this research reviewed case studies of individual historical events, such as the St. Lucens, TMI, Chernobyl, Fukushima accidents and the series of events leading up to the collapse of the Soviet Union. For validation of the results of these case studies, a statistical analysis was conducted using the R code. This will be useful in explaining how international and national decommissioning strategies are affected by shutdown reasons, i.e. world historical events. The number of permanently shutdown NPPs was selected as an indicator because any relationship between the number of permanently In conclusion, nuclear severe accidents and historical events have an impact on the number of international NPPs that shutdown permanently and cancelled NPP construction. This directly impacts international nuclear decommissioning policy and nuclear energy policy trends. The number of permanently shutdown NPPs was selected as an indicator because any relationship between the number of permanently.

  19. The Impact of Severe Nuclear Accidents on National Decision for Nuclear Decommissioning

    International Nuclear Information System (INIS)

    Suh, Young A; Hornibrook, Carol; Yim, Man Sung

    2016-01-01

    Many researchers have tried to identify the impact of severe nuclear accidents on a country's or international nuclear energy policy [2-3]. However, there is little research on the influence of nuclear accidents and historical events on a country's decision to permanently shutdown an NPP versus international nuclear decommissioning trends. To demonstrate the correlation between a nuclear severe accident and the impact on world nuclear decommissioning, this research reviewed case studies of individual historical events, such as the St. Lucens, TMI, Chernobyl, Fukushima accidents and the series of events leading up to the collapse of the Soviet Union. For validation of the results of these case studies, a statistical analysis was conducted using the R code. This will be useful in explaining how international and national decommissioning strategies are affected by shutdown reasons, i.e. world historical events. The number of permanently shutdown NPPs was selected as an indicator because any relationship between the number of permanently In conclusion, nuclear severe accidents and historical events have an impact on the number of international NPPs that shutdown permanently and cancelled NPP construction. This directly impacts international nuclear decommissioning policy and nuclear energy policy trends. The number of permanently shutdown NPPs was selected as an indicator because any relationship between the number of permanently

  20. Shutdown risk monitoring in TEPCO

    International Nuclear Information System (INIS)

    Sato, Hiroki; Masuda, Takahiro; Denda, Yasutaka; Yoneyama, Mitsuru; Imai, Shun-ichi; Miyata, Koichi

    2009-01-01

    At present, we are introducing risk monitors into our all three nuclear power stations; Fukushima Daiichi, Fukushima Daini and Kashiwazaki Kariwa, with technical support of TEPSYS. By monitoring shutdown risk of each unit, we are trying to optimize risks during outage inspection, and raising staff's awareness for reactor safety. This paper presents our recent shutdown risk monitoring activities in Fukushima Daiichi NPS. Shutdown risk monitoring has been carried out for the past five outages of Fukushima Daiichi NPS. Daily-changing shutdown risk is evaluated in the form of core damage frequency (CDF [/day/reactor]). We also examine high-risk point of outage plan if CDF is greater than the threshold at anytime of outage. The results are delivered to operational and maintenance staff before outage. The threshold value is set ten times as much as CDF of unit in operation. As CDF exceeds the threshold, we try to either change the system configuration, or let workers pay more attention to their works during the high-risk period. We already have some examples of outage plan modification to reduce CDF using the risk monitoring information. Greater number of station staff tends to pay more attention to shutdown risk thanks to these activities. (author)

  1. TRIGA forced shutdowns analysis

    International Nuclear Information System (INIS)

    Negut, Gheorghe; Laslau, Florica

    2008-01-01

    The need for improving the operation leads us to use new methods and strategies. Probabilistic safety assessments and statistical analysis provide insights useful for our reactor operation. This paper is dedicated to analysis of the forced shutdowns during the first reactor operation period, between 1980 to 1989. A forced shutdown data base was designed using data on forced shutdowns collected from the reactor operation logbooks. In order to sort out the forced shutdowns the records have the following fields: - current number, date, equipment failed, failure type (M for mechanical, E for electrical, D for irradiation device, U for human factor failure; - scram mode, SE for external scram, failure of reactor cooling circuits and/or irradiation devices, SR for reactor scram, exceeding of reactor nuclear parameters, SB for reactor scram by control rod drop, SM for manual scram required by the abnormal reactor status; - scram cause, giving more information on the forced shutdown. This data base was processed using DBase III. The data processing techniques are presented. To sort out the data, one of the criteria was the number of scrams per year, failure type, scram mode, etc. There are presented yearly scrams, total operation time in hours, total unavailable time, median unavailable time period, reactor availability A. There are given the formulae used to calculate the reactor operational parameters. There are shown the scrams per year in the 1980 to 1989 period, the reactor operation time per year, the reactor shutdown time per year and the operating time versus down time per year. Total number of scrams in the covered period was 643 which caused a reactor down time of 4282.25 hours. In a table the scrams as sorted on the failure type is shown. Summarising, this study emphasized some problems and difficulties which occurred during the TRIGA reactor operation at Pitesti. One main difficulty in creating this data base was the unstandardized scram record mode. Some times

  2. The search of the best mode of the reserve power supply consumption during the nuclear reactor’s emergency shutdown procedures in case of force majeure circumstances

    Science.gov (United States)

    Zagrebaev, A. M.; Trifonenkov, A. V.

    2017-01-01

    This article deals with the problem of the control mode choice for a power supply system in case of force majeure circumstances. It is not known precisely, when a force majeure incident occurs, but the threatened period is given, when the incident is expected. It is supposed, that force majeure circumstances force nuclear reactor shutdown at the moment of threat coming. In this article the power supply system is considered, which consists of a nuclear reactor and a reserve power supply, for example, a hydroelectric pumped storage power station. The reserve power supply has limited capacity and it doesn’t undergo the threatened incident. The problem of the search of the best reserve supply time-distribution in case of force majeure circumstances is stated. The search is performed according to minimization of power loss and damage to the infrastructure. The software has been developed, which performs automatic numerical search of the approximate optimal control modes for the reserve power supply.

  3. Fuse and application of said fuse to the construction of an emergency shutdown system for a nuclear reactor

    International Nuclear Information System (INIS)

    Taulier, H.H.L.; Brugeille, G.

    1978-01-01

    A fuse device for an automatic emergency shutdown system in fast reactors provides a coupling between a casing tube placed within a fuel can and a series of neutron-absorbing masses held together above the reactor core under normal operating conditions but released in free fall to the lower portion of the casing tube at the level of the reactor core as a result of melting of the fuse when operating characteristics such as temperature or neutron flux attain a level which exceeds a predetermined threshold

  4. Fuse and application of said fuse to the construction of an emergency shutdown system for a nuclear reactor

    International Nuclear Information System (INIS)

    Taulier, H.H.L.; Brugeilles, G.

    1976-01-01

    A fuse device for an automatic emergency shutdown system in fast reactors provides a coupling between a casing tube placed within a fuel can and a series of neutron-absorbing masses held together above the reactor core under normal operating conditions. They are released in free fall to the lower portion of the casing tube at the level of the reactor core as a result of melting of the fuse when operating characteristics such as temperature or neutron flux attain a level which exceeds a predetermined threshold

  5. The Chernobyl plant shutdown

    International Nuclear Information System (INIS)

    2000-12-01

    The Chernobylsk-1 reactor, operational in september 1977 has been stopped in november 1996; the Chernobylsk-2 reactor started in november 1978 is out of order since 1991 following a fire. The Chernobylsk-3 reactor began in 1981. During the last three years it occurs several maintenance operations that stop it. In june 2000, the Ukrainian authorities decided to stop it definitively on the 15. of december (2000). This file handles the subject. it is divided in four chapters: the first one gives the general context of the plant shutdown, the second chapter studies the supporting projects to stop definitively the nuclear plant, the third chapter treats the question of the sarcophagus, and the fourth and final chapter studies the consequences of the accident and the contaminated territories. (N.C.)

  6. Assessment of shutdown management

    International Nuclear Information System (INIS)

    Marion, A.

    1992-01-01

    Over the past several years, there has been a number of events that have occurred during nuclear plant outages. These events included losses of AC power, losses of decay heat removal capability, reductions in shutdown margin, and losses of reactor coolant system inventory. Individually, these events have not posed nor indicated an undue risk to public health and safety. Collectively however, they contributed to a perception that outage activities are not being controlled effectively. This paper reports that for many of these same reasons, events that occur during outages have also been of concern to the industry. These events can have a significant economic impact on a company in addition to their being disruptive to the conduct of an efficient outage. And while we have expended industry resources reviewing these events, we have not been fully effective at addressing the root cause of the problem

  7. Permanent cavity seal ring for a nuclear reactor containment arrangement

    International Nuclear Information System (INIS)

    Swidwa, K.J.; Salton, R.B.; Marshall, J.R.

    1990-01-01

    This patent describes a nuclear reactor containment arrangement. It comprises: a reactor pressure vessel which thermally expands and contracts during cyclic operation of the reactor, the vessel having a peripheral wall and a horizontally outwardly extending flange thereon; a containment wall having a shelf, the wall spaced from and surrounding the peripheral wall of the reactor pressure vessel defining an annular expansion gap therebetween, and an annular ring seal extending across the annular expansion gap to provide a water-tight seal therebetween

  8. Security of supply and line flow following the shut-down of nuclear power plants in Germany. Have shortages to be expected?

    International Nuclear Information System (INIS)

    Kunz, Friedrich; Moest, Dominik

    2011-01-01

    This paper, which examines the impacts of phasing out nuclear power in Germany, is the first to include an analysis of energy supply security and critical line flows in both the German and Central European electricity networks. The technical-economic model of the European electricity market, ELMOD, is used to simulate alternative power plant dispatch, imports, exports, and network use for a representative winter day. The results suggest that the shutdown of Germany's nuclear plants will result in higher net imports, especially from the Netherlands, Austria, and Poland, and that electricity generation from fossil fuels will increase slightly in Germany and in Central Europe. We find that no additional imports will come from nuclear plants since they are already fully utilized in the merit order, and that electricity prices will rise on average by a few Euros per MWh. We conclude that closing the seven nuclear power plants within the government's moratorium will cause no significant supply security issues or network constraints and an eventual full phase-out seem to be possible due to the completion of several new conventional power plants now under construction. Finally, we suggest that a nuclear phase-out in Germany within the next 3-7 years will not undermine security of supply and network stability in Germany and Central Europe.

  9. Permanent seal ring for a nuclear reactor cavity

    International Nuclear Information System (INIS)

    Hankinson, M.F.; Marshall, J.R.

    1988-01-01

    A nuclear reactor containment arrangement is described including: a. a reactor vessel which thermally expands and contracts during cyclic operation of the reactor and which has a peripheral wall; b. a containment wall spaced apart from and surrounding the peripheral wall of the reactor vessel and defining an annular thermal expansion gap therebetween for accommodating thermal expansion; and c. an annular ring seal which sealingly engages and is affixed to and extends between the peripheral wall of the reactor vessel and the containment wall

  10. Observations and insights from low power and shutdown studies: Grand Gulf Nuclear Power Plant during POS 5 of a refueling outage

    International Nuclear Information System (INIS)

    Whitehead, D.W.; Brown, T.D.; Forester, J.A.

    1995-04-01

    With the recent completion of the documentation of the results from the Grand Gulf Nuclear Power Plant Low Power and Shutdown (LP and S) project funded by the US Nuclear Regulatory Commission (NRC), detailed probabilistic risk assessment (PRA) information from a boiling water reactor (BWR) for a specific time period in LP and S conditions became available for examination. This report contains observations and insights extracted from an examination of: (1) results in the LP and S documentation; (2) the specific models and assumptions used in the LP and S analyses; (3) selected results from the full-power analysis; (4) the experience of the analysts who performed the original LP and S study; and (5) results from sensitivity calculations performed as part of this project to help determine the impact that model assumptions and data values had on the results from the original LP and S analysis. Specifically, this study makes observations on and develops insights from the estimates of core damage frequency and aggregate risk (early fatalities and total latent cancer fatalities) associated with operations during plant operational state (POS) 5 (i.e., basically cold shutdown as defined by Technical Specifications) during a refueling outage for traditional internal events. A discussion of similarities and differences between full power accidents and accidents during LP and S conditions is provided. As part of this discussion, core damage frequency and risks results are presented on a per hour and per calendar year basis, allowing alternative perspectives on both the core damage frequency and risk associated with these two operational states

  11. Conditioning of spent nuclear fuel for permanent disposal

    International Nuclear Information System (INIS)

    Laidler, J.J.

    1994-01-01

    A compact, efficient method for conditioning spent nuclear fuel is under development This method, known as pyrochemical processing, or open-quotes pyroprocessing,close quotes provides a separation of fission products from the actinide elements present in spent fuel and further separates pure uranium from the transuranic elements. The process can facilitate the timely and environmentally-sound treatment of the highly diverse collection of spent fuel currently in the inventory of the United States Department of Energy (DOE). The pyroprocess utilizes elevated-temperature processes to prepare spent fuel for fission product separation; that separation is accomplished by a molten salt electrorefining step that provides efficient (99.9%) separation of transuranics. The resultant waste forms from the pyroprocess are stable under envisioned repository environment conditions and highly leach-resistant. Treatment of any spent fuel type produces a set of common high-level waste forms, one a mineral and the other a metal alloy, that can be readily qualified for repository disposal and preclude the substantial costs that would be associated with the qualification of the numerous spent fuel types included in the DOE inventory

  12. Communicating on nuclear in Switzerland: a permanent referendum campaign

    International Nuclear Information System (INIS)

    Aegerter, I.; Bucher, P.

    1993-01-01

    Utility and industry representatives took part in numerous discussions and gave many talks seeking a direct dialogue with the consumers and voters. The strategy was and still is to play the role of the consultant and energy specialist. This implies to avoid imposing an opinion and is particularly important, because the Swiss power sector is often not allowed to take part in political debates due to its structure. Many utilities are under the auspices of cantonal and community Authorities, and because people expect that the utilities have expert knowledge in this field. In order to reach a maximum number of people regular, forum-like advertisement in the print media addressed some of the main concerns. In order to show opening for dialogue platforms are needed, either the mass media or any other public information channel. In order to be heard by a public which often complains that the message is not there, a professional approach and a snappy presentation, hence a certain budget, is needed. This is also one of the lessons learned-not only from the utilities experiences but also from a critical analysis of the anti-nuclear group's campaign

  13. Conditioning of spent nuclear fuel for permanent disposal

    International Nuclear Information System (INIS)

    Laidler, J.J.

    1994-01-01

    A compact, efficient method for conditioning spent nuclear fuel is under development. This method, known as pyrochemical processing, or pyroprocessing, provides a separation of fission products from the actinide elements present in spent fuel and further separates pure uranium from the transuranic elements. The process can facilitate the timely and environmentally-sound treatment of the highly diverse collection of spent fuel currently in the inventory of the US Department of Energy (DOE). The pyroprocess utilizes elevated-temperature processes to prepare spent fuel for fission product separation; that separation is accomplished by a molten salt electrorefining step that provides efficient (> 99.9%) separation of transuranics. The resultant waste forms from the pyroprocess are stable under envisioned repository environment conditions and highly leach-resistant. Treatment of any spent fuel type produces a set of common high-level waste forms, one a mineral and the other a metal alloy, that can be readily qualified for repository disposal and that avoid the substantial costs that would be associated with the qualification of the numerous spent fuel types included in the DOE inventory

  14. Perspectives on Low Power and Shutdown Risk

    International Nuclear Information System (INIS)

    Camp, Allen L.; Whitehead, Donnie W.; Wheeler, Timothy A.; Lehner, John; Chu, Tsong-Lun; Lois, Erasmai; Drouin, Mary

    2000-01-01

    This paper presents results from a program sponsored by the US Nuclear Regulatory Commission to examine the risks from low power and shutdown operations. Significant progress has been made by the industry in reducing such risks; however, important operational events continue to occur. Current perceptions of low power and shutdown risks are discussed in the paper along with an assessment of the current methods for understanding important events and quantifying their associated risk

  15. Post shut-down decay heat removal from nuclear reactor core by natural convection loops in sodium pool

    Energy Technology Data Exchange (ETDEWEB)

    Rajamani, A. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Sundararajan, T., E-mail: tsundar@iitm.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Prasad, B.V.S.S.S. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Parthasarathy, U.; Velusamy, K. [Nuclear Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2016-05-15

    Highlights: • Transient simulations are performed for a worst case scenario of station black-out. • Inter-wrapper flow between various sub-assemblies reduces peak core temperature. • Various natural convection paths limits fuel clad temperatures below critical level. - Abstract: The 500 MWe Indian pool type Prototype Fast Breeder Reactor (PFBR) has a passive core cooling system, known as the Safety Grade Decay Heat Removal System (SGDHRS) which aids to remove decay heat after shut down phase. Immediately after reactor shut down the fission products in the core continue to generate heat due to beta decay which exponentially decreases with time. In the event of a complete station blackout, the coolant pump system may not be available and the safety grade decay heat removal system transports the decay heat from the core and dissipates it safely to the atmosphere. Apart from SGDHRS, various natural convection loops in the sodium pool carry the heat away from the core and deposit it temporarily in the sodium pool. The buoyancy driven flow through the small inter-wrapper gaps (known as inter-wrapper flow) between fuel subassemblies plays an important role in carrying the decay heat from the sub-assemblies to the hot sodium pool, immediately after reactor shut down. This paper presents the transient prediction of flow and temperature evolution in the reactor subassemblies and the sodium pool, coupled with the safety grade decay heat removal system. It is shown that with a properly sized decay heat exchanger based on liquid sodium and air chimney stacks, the post shutdown decay heat can be safely dissipated to atmospheric air passively.

  16. Accident analyses in nuclear power plants following external initiating events and in the shutdown state. Final report

    International Nuclear Information System (INIS)

    Loeffler, Horst; Kowalik, Michael; Mildenberger, Oliver; Hage, Michael

    2016-06-01

    The work which is documented here provides the methodological basis for improvement of the state of knowledge for accident sequences after plant external initiating events and for accident sequences which begin in the shutdown state. The analyses have been done for a PWR and for a BWR reference plant. The work has been supported by the German federal ministry BMUB under the label 3612R01361. Top objectives of the work are: - Identify relevant event sequences in order to define characteristic initial and boundary conditions - Perform accident analysis of selected sequences - Evaluate the relevance of accident sequences in a qualitative way The accident analysis is performed with the code MELCOR 1.8.6. The applied input data set has been significantly improved compared to previous analyses. The event tree method which is established in PSA level 2 has been applied for creating a structure for a unified summarization and evaluation of the results from the accident analyses. The computer code EVNTRE has been applied for this purpose. In contrast to a PSA level 2, the branching probabilities of the event tree have not been determined with the usual accuracy, but they are given in an approximate way only. For the PWR, the analyses show a considerable protective effect of the containment also in the case of beyond design events. For the BWR, there is a rather high probability for containment failure under core melt impact, but nevertheless the release of radionuclides into the environment is very limited because of plant internal retention mechanisms. This report concludes with remarks about existing knowledge gaps and with regard to core melt sequences, and about possible improvements of the plant safety.

  17. Report of a consultants meeting on accidents during shutdown conditions for WWER nuclear power plants. Extrabudgetary programme on the safety of WWER NPPs

    International Nuclear Information System (INIS)

    1996-07-01

    The main objectives of the meeting were to exchange information on the operational occurrences, studies performed and countermeasures taken for the accidents during shutdown for WWERs, and to define the necessity and directions of the further activities which may promote the improvement of WWER safety under shutdown conditions. The consultants have discussed some aspects concerning vulnerability of safety functions during shutdown conditions, several steps required to performed accident analysis and selected operational aspects for shutdown conditions. The discussion was supported by an evaluation of selected operational occurrences. The consultants have agreed that the discussion during the meeting in major parts is relevant to all the WWER designs (i.e. WWER-1000, WWER-440/213 and WWER-440/230). As for the plant conditions, the consultants have agreed to bound the discussion mainly by the cold shutdown and refuelling modes. Refs, figs, tabs

  18. Communication from the Permanent Mission of Israel to the International Atomic Energy Agency regarding nuclear export controls

    International Nuclear Information System (INIS)

    2004-01-01

    The Director General of the International Atomic Energy Agency has received a letter dated 13 July 2004 from the Permanent Mission of Israel providing information on Israel's nuclear export policies and practices. As requested by the Permanent Mission, the letter and document attached to it are reproduced herein for the information of Member States

  19. CANDU passive shutdown systems

    Energy Technology Data Exchange (ETDEWEB)

    Hart, R S; Olmstead, R A [AECL CANDU, Sheridan Park Research Community, Mississauga, ON (Canada)

    1996-12-01

    CANDU incorporates two diverse, passive shutdown systems, independent of each other and from the reactor regulating system. Both shutdown systems function in the low pressure, low temperature, moderator which surrounds the fuel channels. The shutdown systems are functionally different, physically separate, and passive since the driving force for SDS1 is gravity and the driving force for SDS2 is stored energy. The physics of the reactor core itself ensures a degree of passive safety in that the relatively long prompt neutron generation time inherent in the design of CANDU reactors tend to retard power excursions and reduces the speed required for shutdown action, even for large postulated reactivity increases. All passive systems include a number of active components or initiators. Hence, an important aspect of passive systems is the inclusion of fail safe (activated by active component failure) operation. The mechanisms that achieve the fail safe action should be passive. Consequently the passive performance of the CANDU shutdown systems extends beyond their basic modes of operation to include fail safe operation based on natural phenomenon or stored energy. For example, loss of power to the SDS1 clutches results in the drop of the shutdown rods by gravity, loss of power or instrument air to the injection valves of SDS2 results in valve opening via spring action, and rigorous self checking of logic, data and timing by the shutdown systems computers assures a fail safe reactor trip through the collapse of a fluctuating magnetic field or the discharge of a capacitor. Event statistics from operating CANDU stations indicate a significant decrease in protection system faults that could lead to loss of production and elimination of protection system faults that could lead to loss of protection. This paper provides a comprehensive description of the passive shutdown systems employed by CANDU. (author). 4 figs, 3 tabs.

  20. Communication received from the Permanent Mission of New Zealand regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    1995-01-01

    The Director General has received a note verbale dated 22 December 1994 from the Permanent Mission of New Zealand to the International Atomic Energy Agency providing information on the nuclear export policies and practices of the Government of New Zealand

  1. A study on the Safe Operation of RHRS during Shut-Down and Low Power Operations of Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Moon Hun; Sung, Chang Kyung; Kim, Yang Suk; You, Sun Oh; Joo, In Chul [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-08-01

    The main objective is to perform basic research for safe operation of RHRs, which is an important part in the safety analysis of nuclear reactors during a mid-loop operation of nuclear power plants. To achieve this objective, a series of experiments have been performed to simulate the wave phenomena of countercurrent flow that may occur in the hot legs during a mid-loop operation. The major contents and the scope are as follows, To collect and to analyse existing experimental works and also numerical works which have been carried out using large computer codes. To collect and to analyse existing works on the flow patterns of two-phase flows. To perform a series of experiments to simulate the wave phenomena for the countercurrent two-phase flow in hot legs. To obtain correlations for the interfacial friction factor and the flow patterns for a countercurrent flow from the experimentally measured parameters. To obtain the interfacial friction factor between the two-phases of air-water countercurrent flow in a horizontal pipe, a series of experiments have been performed using two different sections of 0.05 m in diameter, whose lengths are 2 m and 4 m, respectively. The results presented here can be used as the fundamental information to obtain the most important thermal-hydraulic parameters such as flow patterns and interfacial friction factors for air-water two-phase flows, which are necessary for safety analyses and operation of nuclear power plants during a mid-loop operation. 46 refs., 8 tabs., 35 figs., 3 ills. (author)

  2. Shutdown, dismantling and decommissioning of nuclear facilities in France - Guide no. 6 - Update of 30/08/2016

    International Nuclear Information System (INIS)

    2016-01-01

    After a recall of the regulatory context and references, this guide addresses the strategy for an immediate dismantling of an installation, the dismantling planning, the different phases of the end of life of nuclear base installations, the authorization of definitive stop and dismantling, the preliminary phase preparing the definitive stop (regulatory context, technical aspects), the dismantling phase (regulatory context, technical aspects for the concerned operations, the security functions, hardware important for security, taking ageing into account), and the final status of installations (downgrading, constraints)

  3. Safety aspects of unplanned shutdowns and trips

    International Nuclear Information System (INIS)

    1986-05-01

    The issue of unplanned shutdowns and trips is receiving increased attention worldwide in view of its importance to plant safety and availability. There exists significant variation in the number of forced shutdowns for nuclear power plants of the same type operating worldwide. The reduction of the frequency of these events will have safety benefits in terms of reducing the frequency of plant transients and the challenges to the safety systems, and the risks of possible incidents. This report provides an insight into the causes of unplanned shutdowns experienced in operating nuclear power plants worldwide, the good practices that have been found effective in minimizing their occurrence, and the measures that have been taken to reduce these events. Specific information on the experiences, approaches and practices of some countries in dealing with this issue is presented in Appendix A

  4. Reactor shutdown device

    International Nuclear Information System (INIS)

    Inoue, Toyokazu.

    1982-01-01

    Purpose: To obtain a highly reliable reactor shutdown device capable of checking its function irrespective of the state whether shutdown or operation in a gas-cooled type reactor. Constitution: A hopper is disposed above a guide tube inserted into the reactor core and particulate neutron absorbers are contained in the hopper. An opening for falling particles is disposed to the bottom of the hopper in opposition to the upper end of the guide pipe and the opening is closed by a plug suspended by way of a weld line so as to be capable of dropping. A power source for supplying electrical current to the weld line is disposed. Accordingly, if the current is supplied to the weld line, the line is cut by welding to fall the plug so that the neutron-absorbing particles fall from the opening into the guide pipe to shutdown the reactor, whereby high reliability is obtained for the operation. (Seki, T.)

  5. Safety shutdown separators

    Science.gov (United States)

    Carlson, Steven Allen; Anakor, Ifenna Kingsley; Farrell, Greg Robert

    2015-06-30

    The present invention pertains to electrochemical cells which comprise (a) an anode; (b) a cathode; (c) a solid porous separator, such as a polyolefin, xerogel, or inorganic oxide separator; and (d) a nonaqueous electrolyte, wherein the separator comprises a porous membrane having a microporous coating comprising polymer particles which have not coalesced to form a continuous film. This microporous coating on the separator acts as a safety shutdown layer that rapidly increases the internal resistivity and shuts the cell down upon heating to an elevated temperature, such as 110.degree. C. Also provided are methods for increasing the safety of an electrochemical cell by utilizing such separators with a safety shutdown layer.

  6. Communication received from the Permanent Mission of the Netherlands on behalf of the Member States of the Nuclear Suppliers Group

    International Nuclear Information System (INIS)

    2000-01-01

    The document reproduces the text of the updated version of the paper entitled 'The Nuclear Suppliers Group: Its origins, role and activities' received by the Director General of IAEA on 4 April 2000, as attachment to a letter from the Permanent Mission of the Netherlands to the Agency on behalf of the Member States of the 'Nuclear Suppliers Group (NSG)'

  7. Development of Abnormal Operating Strategies for Loss of Ultimate Heat Sink (LOUHS) at Shutdown Mode in Westinghouse Type Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Duk-Joo; Lee, Seung-Chan; Sung, Je-Joong; Ha, Sang Jun [KHNP CRI, Daejeon (Korea, Republic of); Hwang, Su-Hyun [FNC Tech. Co., Yongin (Korea, Republic of)

    2016-10-15

    Loss of all AC power is classified as one of multiple failure accident by regulatory guide of Korean accident management program. Therefore we need develop strategies for the abnormal operating procedure both of power operating and shutdown mode. This paper developed abnormal operating guideline for loss of all AC power by analysis of accident scenario in pressurized water reactor. This paper analyzed the extended SBO in shutdown operating mode and developed the operating strategy of the abnormal operation procedure. Operator action for the emergency are not required to take in 500 minutes and 60 minutes in intact and opened RCS state respectively.

  8. Plasma shutdown device

    International Nuclear Information System (INIS)

    Hosogane, Nobuyuki; Nakayama, Takahide.

    1985-01-01

    Purpose: To prevent concentration of plasma currents to the plasma center upon plasma shutdown in a torus type thermonuclear device by the injection of fuels to the plasma center thereby prevent plasma disruption at the plasma center. Constitution: The plasma shutdown device comprises a plasma current measuring device that measures the current distribution of plasmas confined within a vacuum vessel and outputs a control signal for cooling the plasma center when the plasma currents concentrate to the plasma center and a fuel supply device that supplies fuels to the plasma center for cooling the center. The fuels are injected in the form of pellets into the plasmas. The direction and the velocity of the injection are set such that the pellets are ionized at the center of the plasmas. (Horiuchi, T.)

  9. 77 FR 75198 - Standard Format and Content for Post-Shutdown Decommissioning Activities Report

    Science.gov (United States)

    2012-12-19

    ... NUCLEAR REGULATORY COMMISSION [NRC-2012-0299] Standard Format and Content for Post-Shutdown... regulatory guide (DG), DG-1272, ``Standard Format and Content for Post-shutdown Decommissioning Activities... Content for Post-shutdown Decommissioning Activities Report,'' which was issued in July 2000. DG-1271...

  10. Reversing nuclear opposition: evolving public acceptance of a permanent nuclear waste disposal facility.

    Science.gov (United States)

    Jenkins-Smith, Hank C; Silva, Carol L; Nowlin, Matthew C; deLozier, Grant

    2011-04-01

    Nuclear facilities have long been seen as the top of the list of locally unwanted land uses (LULUs), with nuclear waste repositories generating the greatest opposition. Focusing on the case of the Waste Isolation Pilot Plant (WIPP) in southern New Mexico, we test competing hypotheses concerning the sources of opposition and support for siting the facility, including demographics, proximity, political ideology, and partisanship, and the unfolding policy process over time. This study tracks the changes of risk perception and acceptance of WIPP over a decade, using measures taken from 35 statewide surveys of New Mexico citizens spanning an 11-year period from fall 1990 to summer 2001. This time span includes periods before and after WIPP became operational. We find that acceptance of WIPP is greater among those whose residences are closest to the WIPP facility. Surprisingly, and contrary to expectations drawn from the broader literature, acceptance is also greater among those who live closest to the nuclear waste transportation route. We also find that ideology, partisanship, government approval, and broader environmental concerns influence support for WIPP acceptance. Finally, the sequence of procedural steps taken toward formal approval of WIPP by government agencies proved to be important to gaining public acceptance, the most significant being the opening of the WIPP facility itself. © 2010 Society for Risk Analysis.

  11. Facing the nuclear power phaseout - Swedish experiences of enterprise shutdown and organisational development; Infoer kaernkraftavveckling - svenska erfarenheter av foeretagsnedlaeggningar och foeraendringsarbete

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, K. [Castor AB, Stockholm (Sweden)

    1998-02-01

    The aim of this study is to make an overview of problems and experiences connected to decommissioning and organisational changes of Swedish enterprises and public agencies from a safety perspective. The central point is the view of decommissioning of nuclear power plants as a process of change. In practice decommissioning includes both downsizing and organisational development. The question is which problems can arise and which strategy of change is most adequate from the standpoint of safety. The report starts with a summary of the most important experiences of the process of decommissioning of enterprises during the sixties to eighties concerning the consequences for the individuals and the labour market. After that follows the main results from earlier investigations of shut-down of nuclear power plants regarding the staff. The restructuring and downsizing of the public sector during the nineties have given rise to a large amount of material on staffing issues. The knowledge and experiences drawn from the organisational change processes of Swedish working life during the nineties are then summarised. At last some conclusions for decommissioning of nuclear power plants are discussed. The period before and after the termination of power generation is connected with great strain. The vulnerability of the staff increases and the faith in management can easily be destroyed, which can affect safety and the decommissioning work. The feeling of security increases if the staff continuously is kept informed and within certain limits can influence the course of events. A learning strategy is preferable in comparison to an expert oriented strategy because it is impossible to gain complete control over the technically and socially complex process of decommissioning. Instead of detailed and central planning of the process it will be safer to work in a participative way and to include all the staff in the preparations from the very beginning. By a learning way of working is

  12. Information on the activity of the Atomehnergo permanent commettee of CMEA in the area of peaceful use of nuclear energy

    International Nuclear Information System (INIS)

    Malek, Z.

    1984-01-01

    Activity of the CMEA permanent committee on the peaceful use of nuclear energy is briefly outlines. It is pointed out, that data, presented to the conferences and consultations of the Committee, can be used as numerical, when constructing data retrieval systems

  13. CANDU 6 liquid injection shutdown system waterhammer analysis using PTRAN

    International Nuclear Information System (INIS)

    Ko, Deuk Yoon; Kim, Eun Ki; Ko, Yong Sang; Park, Byung Ho; Kim, Seok Bum

    1996-06-01

    An in-core LOCA could result in flooding of the helium header in the liquid injection shutdown system. Flooding of the helium header will result in severe pressure transients (waterhammer) in the liquid injection shutdown system when the shutdown signal is initiated. To evaluate the impact of the dynamic effects of this event, a pressure transient analysis has been performed. This analysis is performed using PTRAN, which is a computer program based on the method of characteristics. The results of this analysis are used in the stress analysis of the piping and pipe supports to ensure that the liquid injection shutdown system can withstand the pressure transient loadings. This analysis report documents the results of waterhammer analysis performed for the liquid injection shutdown system for the Wolsung nuclear power plant unit 2, 3 and 4. 4 tabs., 11 figs., 15 refs. (Author)

  14. CANDU 6 liquid injection shutdown system waterhammer analysis using PTRAN

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Deuk Yoon; Kim, Eun Ki; Ko, Yong Sang; Park, Byung Ho; Kim, Seok Bum [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-01

    An in-core LOCA could result in flooding of the helium header in the liquid injection shutdown system. Flooding of the helium header will result in severe pressure transients (waterhammer) in the liquid injection shutdown system when the shutdown signal is initiated. To evaluate the impact of the dynamic effects of this event, a pressure transient analysis has been performed. This analysis is performed using PTRAN, which is a computer program based on the method of characteristics. The results of this analysis are used in the stress analysis of the piping and pipe supports to ensure that the liquid injection shutdown system can withstand the pressure transient loadings. This analysis report documents the results of waterhammer analysis performed for the liquid injection shutdown system for the Wolsung nuclear power plant unit 2, 3 and 4. 4 tabs., 11 figs., 15 refs. (Author).

  15. Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study.

    Science.gov (United States)

    Vogel, Michael W; Giorni, Andrea; Vegh, Viktor; Pellicer-Guridi, Ruben; Reutens, David C

    2016-01-01

    We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability. The finite element method (COMSOL®) was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field. A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20-50 μT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres. A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably.

  16. Oak Ridge Research reactor shutdown maintenance and surveillance

    International Nuclear Information System (INIS)

    Coleman, G.H.; Laughlin, D.L.

    1991-05-01

    The Department of Energy ordered the Oak Ridge Research Reactor to be placed in permanent shutdown on July 14, 1987. The paper outlines routine maintenance activities and surveillance tests performed April through September, 1990, on the reactor instrumentation and controls, process system, and the gaseous waste filter system. Preparations are being made to transfer the facility to the Remedial Action Program. 6 tabs

  17. Reactor shutdown device

    International Nuclear Information System (INIS)

    Matsumiya, Hirohito; Endo, Hiroshi; Tsuboi, Yasushi.

    1993-01-01

    The present invention concerns a reactor shutdown device capable of suppressing change of a core insertion amount relative to temperature change during normal operation and having a great extension amount due to thermal expansion and high mechanical strength. A control rod main body is contained vertically movably in a guide tube disposed in a reactor core. An extension member extends upward from the upper end of a control rod main body and suspends the control rod main body. A shrinkable member intervenes at a midway of the extension member and is made shrinkable. A temperature sensitive member contains coolants at the inside and surrounds the shrinkable member. Thus, if the temperature of external coolants rises abruptly, the shrinkable member is extended by thermal expansion of the coolants in the temperature sensitive member. Upon usual reactor startup, the coolants in the temperature sensitive member cause no substantial thermal expansion by temperature elevation from a cold shutdown temperature to a rated power operation temperature, and the shrinkable member maintains its original state, so that the control rod main body is not inserted into the reactor core. However, upon abrupt temperature elevation, the control rod main body is inserted into the reactor core. (I.S.)

  18. Shutdown problems in large tokamaks

    International Nuclear Information System (INIS)

    Weldon, D.M.

    1978-01-01

    Some of the problems connected with a normal shutdown at the end of the burn phase (soft shutdown) and with a shutdown caused by disruptive instability (hard shutdown) have been considered. For a soft shutdown a cursory literature search was undertaken and methods for controlling the thermal wall loading were listed. Because shutdown computer codes are not widespread, some of the differences between start-up codes and shutdown codes were discussed along with program changes needed to change a start-up code to a shutdown code. For a hard shutdown, the major problems are large induced voltages in the ohmic-heating and equilibrium-field coils and high first wall erosion. A literature search of plasma-wall interactions was carried out. Phenomena that occur at the plasma-wall interface can be quite complicated. For example, material evaporated from the wall can form a virtual limiter or shield protecting the wall from major damage. Thermal gradients that occur during the interaction can produce currents whose associated magnetic field also helps shield the wall

  19. CAREM-25 Reactor Second Shutdown System Consolidation Analysis

    International Nuclear Information System (INIS)

    Gimenez, Marcelo; Zanocco, Pablo; Schlamp, Miguel

    2000-01-01

    CAREM Reactor Second Shutdown System (SSS) injects boron into the primary circuit in case of First Shutdown System failure in order to stop the nuclear reaction and to maintain the core in a safe condition during cold shutdown.It also has another safety function which is to inject water in the primary system at any pressure in case of LOCA.Different system requirements are analyzed during a SSS spurious trip and LOCA's transients.Two different alternatives are presented for the stand by condition pressurized system, they are solid mode and hot water layer. Both cases fulfill the design requirements from the safety point of view

  20. Emergency reactor shutdown device

    International Nuclear Information System (INIS)

    Ikehara, Morihiko.

    1982-01-01

    Purpose: To smoothen the emergency operation of the control rod in a BWR type reactor and to eliminate the external discharge of radioactively contaminated water. Constitution: A drain receiving tank is connected through a scram valve to the top of a cylinder which is containing a hydraulic piston connected to a trombone-shaped control rod and an accumulator is connected through another scram valve to the bottom of the cylinder. The respective scram valves are constructed to be opened by the reactor emergency shutdown signal from a reactor control system in such a manner that drain valve and a vent valve of the tank normally opened at the standby time are closed after approx. 10 seconds from the opening of the scram valves. In this manner, back pressure is not applied to the hydraulic piston at the emergency time, thereby smoothly operating the control rod. (Sikiya, K.)

  1. Reactor shutdown device

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Kiyoshi; Aono, Hidehiro [Hitachi Ltd., Tokyo (Japan); Fujita, Kaoru; Ishikawa, Tsuyoshi

    1996-02-20

    The present invention concerns a reactor shutdown device of a LMFBR type reactor, and provides a magnetic circuit having a sharp changing property of holding force relative to temperature change. Namely, a magnetic bridge is attached to a portion of the magnetic circuit. Then, required conditions are satisfied. Alternatively, even if the temperature dependent change of magnetic saturation of a temperature sensing alloy itself is somewhat moderated, the holding force from an erroneous dropping preventive temperature to a separating temperature can be abruptly reduced while keeping the holding force at a temperature lower than the erroneous dropping preventive temperature. Provision of the magnetic bridge increases the temperature dependent change of the holding force of the entire magnetic circuit. As a result, margin for the design of the temperature sensing alloy is extended. Actual design is enabled, and the range for selecting the temperature sensing alloy can be enlarged. (I.S.).

  2. Reactor shutdown device

    International Nuclear Information System (INIS)

    Harada, Kiyoshi; Aono, Hidehiro; Fujita, Kaoru; Ishikawa, Tsuyoshi.

    1996-01-01

    The present invention concerns a reactor shutdown device of a LMFBR type reactor, and provides a magnetic circuit having a sharp changing property of holding force relative to temperature change. Namely, a magnetic bridge is attached to a portion of the magnetic circuit. Then, required conditions are satisfied. Alternatively, even if the temperature dependent change of magnetic saturation of a temperature sensing alloy itself is somewhat moderated, the holding force from an erroneous dropping preventive temperature to a separating temperature can be abruptly reduced while keeping the holding force at a temperature lower than the erroneous dropping preventive temperature. Provision of the magnetic bridge increases the temperature dependent change of the holding force of the entire magnetic circuit. As a result, margin for the design of the temperature sensing alloy is extended. Actual design is enabled, and the range for selecting the temperature sensing alloy can be enlarged. (I.S.)

  3. Magnetic disconnect for secondary shutdown

    International Nuclear Information System (INIS)

    Lessor, D.L.

    1972-01-01

    A description is given of studies to develop a magnetic holding clutch in the control rod drive line as an alternate shutdown device for the FFTF. Results indicate that a three-phase disconnect, hold, and backup shutdown system can be designed to operate satisfactorily. (U.S.)

  4. Communication received from the Permanent Mission of the Netherlands on behalf of the Member States of the Nuclear Suppliers Group

    International Nuclear Information System (INIS)

    2000-01-01

    The Director General has received a letter dated 4 April 2000 from the Permanent Mission of the Netherlands to the Agency on behalf of Member States of the 'Nuclear Suppliers Group' (NSG). Attached to this letter is an updated version of a paper entitled 'The Nuclear Suppliers Group: Its Origins, Roles and Activities'. The original version of the paper was issued as INFCIRC/539 on 15 September 1997. In the light of the wish expressed at the end of the letter, the revised version of the paper, attached hereto, is being circulated to Member States of the IAEA as INFCIRC/539/Rev.1

  5. Communication received from the permanent mission of Australia on behalf of the Member States of the nuclear suppliers group

    International Nuclear Information System (INIS)

    1997-01-01

    The document reproduces the text of a letter dated 13 August 1997 received by the Director General of the IAEA from the Permanent Mission of Australia to the Agency on behalf of the Member States of the 'Nuclear Suppliers Group (NSG)'. Attached to this letter was a paper entitled 'The Nuclear Suppliers Group: Its origins, role and activities'. The purpose of the letter and the attached paper was to provide detailed background to the origins of guidelines that govern the export of items exclusively for nuclear use and the export of nuclear related dual-use items and technologies. These guidelines were published by the Agency in documents INFCIRC/254/Rev.3/Part 1 and INFCIRC/254/Rev.2/Part 2/Mod.1

  6. Optimal shutdown management

    International Nuclear Information System (INIS)

    Bottasso, C L; Croce, A; Riboldi, C E D

    2014-01-01

    The paper presents a novel approach for the synthesis of the open-loop pitch profile during emergency shutdowns. The problem is of interest in the design of wind turbines, as such maneuvers often generate design driving loads on some of the machine components. The pitch profile synthesis is formulated as a constrained optimal control problem, solved numerically using a direct single shooting approach. A cost function expressing a compromise between load reduction and rotor overspeed is minimized with respect to the unknown blade pitch profile. Constraints may include a load reduction not-to-exceed the next dominating loads, a not-to-be-exceeded maximum rotor speed, and a maximum achievable blade pitch rate. Cost function and constraints are computed over a possibly large number of operating conditions, defined so as to cover as well as possible the operating situations encountered in the lifetime of the machine. All such conditions are simulated by using a high-fidelity aeroservoelastic model of the wind turbine, ensuring the accuracy of the evaluation of all relevant parameters. The paper demonstrates the capabilities of the novel proposed formulation, by optimizing the pitch profile of a multi-MW wind turbine. Results show that the procedure can reliably identify optimal pitch profiles that reduce design-driving loads, in a fully automated way

  7. Optimal shutdown management

    Science.gov (United States)

    Bottasso, C. L.; Croce, A.; Riboldi, C. E. D.

    2014-06-01

    The paper presents a novel approach for the synthesis of the open-loop pitch profile during emergency shutdowns. The problem is of interest in the design of wind turbines, as such maneuvers often generate design driving loads on some of the machine components. The pitch profile synthesis is formulated as a constrained optimal control problem, solved numerically using a direct single shooting approach. A cost function expressing a compromise between load reduction and rotor overspeed is minimized with respect to the unknown blade pitch profile. Constraints may include a load reduction not-to-exceed the next dominating loads, a not-to-be-exceeded maximum rotor speed, and a maximum achievable blade pitch rate. Cost function and constraints are computed over a possibly large number of operating conditions, defined so as to cover as well as possible the operating situations encountered in the lifetime of the machine. All such conditions are simulated by using a high-fidelity aeroservoelastic model of the wind turbine, ensuring the accuracy of the evaluation of all relevant parameters. The paper demonstrates the capabilities of the novel proposed formulation, by optimizing the pitch profile of a multi-MW wind turbine. Results show that the procedure can reliably identify optimal pitch profiles that reduce design-driving loads, in a fully automated way.

  8. Reactor shutdown device

    International Nuclear Information System (INIS)

    Ito, Masahiko

    1990-01-01

    The object of the present invention is to reliably shutdown an LMFBR type reactor upon accident of the reactor. That is, curie point magnetic member is made annular so that it can be moved between the outer circumference of an electromagnet and the position above the electromagnet. This enables to enlarge the curie point magnetic member since it is no more necessary to be inserted it in a guide tube. Accordingly, attracting force upon normal operation is increased to remarkably improve the reliability against erronerous scram, etc. Further, since a required gap is formed between the curie point magnetic member and the electromagnet and the heat of coolants is efficiently transmitted to the curie point magnetic member, rapid scram is possible. Further, a position support mechanism is disposed to a part of a control element or at the inner side of the guiding tube for urging and actuating the armature to make it protrude above the top of the guiding tube. With such a constitution, since the armature can be adsorbed without inserting the curie point magnetic member and the electromagnet guide tube, the same effect as in the case of inserting them can be obtained. (I.S.)

  9. 78 FR 49553 - Three Mile Island, Unit 2; Post Shutdown Decommissioning Activities Report

    Science.gov (United States)

    2013-08-14

    ... NUCLEAR REGULATORY COMMISSION [Docket No. 50-320; NRC-2013-0183] Three Mile Island, Unit 2; Post Shutdown Decommissioning Activities Report AGENCY: Nuclear Regulatory Commission. ACTION: Notice of receipt... Shutdown Decommissioning Activity Report (PSDAR) for Three Mile Island, Unit 2 (TMI-2). The PSDAR provides...

  10. 77 FR 10576 - Methodology for Low Power/Shutdown Fire PRA

    Science.gov (United States)

    2012-02-22

    ... NUCLEAR REGULATORY COMMISSION [NRC-2011-0295] Methodology for Low Power/Shutdown Fire PRA AGENCY.../Shutdown Fire PRA.'' In response to request from members of the public, the NRC is extending the public... risk assessment (PRA) method for quantitatively analyzing fire risk in commercial nuclear power plants...

  11. 76 FR 81998 - Methodology for Low Power/Shutdown Fire PRA

    Science.gov (United States)

    2011-12-29

    ... NUCLEAR REGULATORY COMMISSION [NRC-2011-0295] Methodology for Low Power/Shutdown Fire PRA AGENCY..., ``Methodology for Low Power/Shutdown Fire PRA--Draft Report for Comment.'' DATES: Submit comments by March 01... risk assessment (PRA) method for quantitatively analyzing fire risk in commercial nuclear power plants...

  12. 78 FR 38739 - Standard Format and Content for Post-Shutdown Decommissioning Activities Report

    Science.gov (United States)

    2013-06-27

    ... NUCLEAR REGULATORY COMMISSION [NRC-2012-0299] Standard Format and Content for Post-Shutdown Decommissioning Activities Report AGENCY: Nuclear Regulatory Commission. ACTION: Regulatory guide; issuance..., ``Standard Format and Content for Post-shutdown Decommissioning Activities Report.'' This guide describes a...

  13. Communication received on 12 September 2006 from the Permanent Mission of Japan to the Agency concerning arrangements for the assurance of nuclear fuel supply

    International Nuclear Information System (INIS)

    2006-01-01

    The Secretariat has received on 12 September 2006 a communication from the Permanent Mission of Japan attaching a document entitled 'Japan's Proposal: IAEA Standby Arrangements System for the Assurance of Nuclear Fuel Supply'. As requested by the Permanent Mission, the text of the attachment is herewith reproduced for the information of Member States

  14. Communication dated 8 April 2014 received from the Permanent Mission of the Netherlands to the Agency regarding The Hague Nuclear Security Summit Communiqué

    International Nuclear Information System (INIS)

    2014-01-01

    The Director General has received a communication dated 8 April 2014 from the Permanent Mission of the Netherlands to the Agency, enclosing the Communiqué of the Nuclear Security Summit 2014, which took place on 24-25 March 2014 in The Hague. The communication and, as requested by the Permanent Mission, the Communiqué are circulated herewith for information [es

  15. Communication dated 8 April 2014 received from the Permanent Mission of the Netherlands to the Agency regarding The Hague Nuclear Security Summit Communiqué

    International Nuclear Information System (INIS)

    2014-01-01

    The Director General has received a communication dated 8 April 2014 from the Permanent Mission of the Netherlands to the Agency, enclosing the Communiqué of the Nuclear Security Summit 2014, which took place on 24-25 March 2014 in The Hague. The communication and, as requested by the Permanent Mission, the Communiqué are circulated herewith for information

  16. Startup, Shutdown, & Malfunction (SSM) Emissions

    Science.gov (United States)

    EPA issued a final action to ensure states have plans in place that are fully consistent with the Clean Air Act and recent court decisions concerning startup, shutdown and malfunction (SSM) operations.

  17. Study of methodology for low power/shutdown fire PSA

    International Nuclear Information System (INIS)

    Yan Zhen; Li Zhaohua; Li Lin; Song Lei

    2014-01-01

    As a risk assessment technology based on probability, the fire PSA is accepted abroad by nuclear industry in its application in the risk assessment for nuclear power plants. Based on the industry experience, the fire-induced impact on the plant safety during low power and shutdown operation cannot be neglected, therefore fire PSA can be used to assess the corresponding fire risk. However, there is no corresponding domestic guidance/standard as well as accepted analysis methodology up to date. Through investigating the latest evolvement on fire PSA during low power and shutdown operation, and integrating its characteristic with the corresponding engineering experience, an engineering methodology to evaluate the fire risk during low power and shutdown operation for nuclear power plant is established in this paper. In addition, an analysis demonstration as an example is given. (authors)

  18. A Bayesian reliability study on motorized valves for the emergency core cooling, heat transport isolation and shutdown cooling systems at Gentilly-2 Nuclear Generating Station

    International Nuclear Information System (INIS)

    Smith, J.E.; Rennick, D.F.; Nainer, A.

    1996-01-01

    The objective of this is to examine operational data on 32 motorized valves in the emergency core cooling, shutdown cooling and heat transport isolation systems and determine if the evidence would support a reduction in testing frequency of these valves. The methodology used is to examine the data which has accumulated on motorized valve failures since Gentilly-2 first entered service, compare these data with similar data from other sources, and determine whether the evidence indicate that demand-based, wear out type failure mechanisms play a significant role in the recorded failures. The statistical data are then updated, using a Bayesian updating procedure, to obtain revised time based failure rates and demand based probabilities of failure on demand for the motorized valves. The revised failure rates and probabilities are then applied to the fault tree models for the systems of interest to determine what effects there would be, with the current test intervals and with extended test intervals, on the probability of failure of the systems. (author)

  19. Hazard Classification for Fuel Supply Shutdown Facility

    International Nuclear Information System (INIS)

    BENECKE, M.W.

    2000-01-01

    Final hazard classification for the 300 Area N Reactor fuel storage facility resulted in the assignment of Nuclear Facility Hazard Category 3 for the uranium metal fuel and feed material storage buildings (303-A, 303-B, 303-G, 3712, and 3716). Radiological for the residual uranium and thorium oxide storage building and an empty former fuel storage building that may be used for limited radioactive material storage in the future (303-K/3707-G, and 303-E), and Industrial for the remainder of the Fuel Supply Shutdown buildings (303-F/311 Tank Farm, 303-M, 313-S, 333, 334 and Tank Farm, 334-A, and MO-052)

  20. Accident analyses in nuclear power plants following external initiating events and in the shutdown state. Final report; Unfallanalysen in Kernkraftwerken nach anlagenexternen ausloesenden Ereignissen und im Nichtleistungsbetrieb. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, Horst; Kowalik, Michael; Mildenberger, Oliver; Hage, Michael

    2016-06-15

    The work which is documented here provides the methodological basis for improvement of the state of knowledge for accident sequences after plant external initiating events and for accident sequences which begin in the shutdown state. The analyses have been done for a PWR and for a BWR reference plant. The work has been supported by the German federal ministry BMUB under the label 3612R01361. Top objectives of the work are: - Identify relevant event sequences in order to define characteristic initial and boundary conditions - Perform accident analysis of selected sequences - Evaluate the relevance of accident sequences in a qualitative way The accident analysis is performed with the code MELCOR 1.8.6. The applied input data set has been significantly improved compared to previous analyses. The event tree method which is established in PSA level 2 has been applied for creating a structure for a unified summarization and evaluation of the results from the accident analyses. The computer code EVNTRE has been applied for this purpose. In contrast to a PSA level 2, the branching probabilities of the event tree have not been determined with the usual accuracy, but they are given in an approximate way only. For the PWR, the analyses show a considerable protective effect of the containment also in the case of beyond design events. For the BWR, there is a rather high probability for containment failure under core melt impact, but nevertheless the release of radionuclides into the environment is very limited because of plant internal retention mechanisms. This report concludes with remarks about existing knowledge gaps and with regard to core melt sequences, and about possible improvements of the plant safety.

  1. Reliability analysis of shutdown system

    International Nuclear Information System (INIS)

    Kumar, C. Senthil; John Arul, A.; Pal Singh, Om; Suryaprakasa Rao, K.

    2005-01-01

    This paper presents the results of reliability analysis of Shutdown System (SDS) of Indian Prototype Fast Breeder Reactor. Reliability analysis carried out using Fault Tree Analysis predicts a value of 3.5 x 10 -8 /de for failure of shutdown function in case of global faults and 4.4 x 10 -8 /de for local faults. Based on 20 de/y, the frequency of shutdown function failure is 0.7 x 10 -6 /ry, which meets the reliability target, set by the Indian Atomic Energy Regulatory Board. The reliability is limited by Common Cause Failure (CCF) of actuation part of SDS and to a lesser extent CCF of electronic components. The failure frequency of individual systems is -3 /ry, which also meets the safety criteria. Uncertainty analysis indicates a maximum error factor of 5 for the top event unavailability

  2. Communication dated 10 September 2008 received from the Permanent Mission of Germany to the Agency regarding a 'Statement on Civil Nuclear Cooperation with India'

    International Nuclear Information System (INIS)

    2008-01-01

    The Agency has received a communication dated 10 September 2008 from the Permanent Mission of Germany, forwarding a letter from the Chairman of the Nuclear Suppliers Group (NSG) to the Director General attached to which was a 'Statement on Civil Nuclear Cooperation with India' adopted by the NSG. As requested in the communication, the attachment is herewith circulated for information

  3. Nuclear power. BGH ruling of 16.1.1997 (Az: III ZR 117/95) relating to the action for damages in the matter of the shut-down Muehlheim-Kaerl-Kaerlich Reactor

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    The German Federal High Court (BGH) non-appealably rejected part of the claims for damages of the owner/operator of the Muehlheim-Kaerlich nuclear power station asserted in an action against the Federal State of Rhineland-Palatinate and remanded the case to the lower court for clarification of the remaining claims. The plant operator claimed compensation for damage incurred in the wake of the annulment of the first partial permit issued for the nuclear power plant in 1975 and declared to be void for reasons of non-compliance with the licensing provisions of section 7, sub-section 2 AtG (Atomic Energy Act), and breach of official duty of civil servants of the licensing authority of Rhineland-Palatinate. Due to this decision of the Federal Administrative Court, the plant was shut down in 1988. The claims asserted by the operator relate among other items to compensation for construction, operation and shut-down operation costs. (orig./CB) [de

  4. Using management of aging in German nuclear power plants - aspects of KTA 1403 pertaining to residual power operation, post-shutdown operation and residual operation

    International Nuclear Information System (INIS)

    Barreiro, Pablo; Bever, Thomas; Brast, Gerhard; Elsche, Bjoern; Reese, Sven H.; Grossmann, Patrick; Widera, Martin; Huettner, Frank; Linnemann, Thomas; Smit, Swen-Olaf; Zander, Ralf-Michael

    2013-01-01

    Management of aging in nuclear power plants originated in the United States of America and became a topic of debate in Germany from the late 1990s onward. On the basis of the existing plant-specific measures practiced comprehensively, KTA 1403, ''Management of Aging in Nuclear Power Plants'', was drafted and finalized in 2010. This publication first presents the context of AM with regard to German nuclear power plants, including references to national and international historical developments. Against this backdrop, the difference between management of aging and lifetime management is discussed next. This is followed by a description of the status of the AM process in nuclear power plants currently in operation, especially organizational plant-specific implementation. As a consequence of the decision by the German federal government to discontinue the peaceful use of nuclear power in Germany and the associated 13th amendment to the Atomic Energy Act of July 31, 2011, a considerable part of the German nuclear power plant park already lost its right of power operation. In this situation, aspects of AM are discussed for plants in the no-power, post-operation and residual operation phases. Finally, experience accumulated in plant-specific execution of the AM process on the basis of KTA 1403 is considered and summarized.

  5. Development of moving alternating magnetic filter using permanent magnet for removal of radioactive corrosion product from nuclear power plant

    International Nuclear Information System (INIS)

    Song, M. C.; Kim, S. I.; Lee, K. J.

    2002-01-01

    Radioactive Corrosion Products (CRUD) which are generated by the neutron activation of general corrosion products at the nuclear power plant are the major source of occupational radiation exposure. Most of the CRUD has a characteristic of showing strong ferrimagnetisms. Along with the new development and production of permanent magnet (rare earth magnet) which generates much stronger magnetic field than the conventional magnet, new type of magnetic filter that can separate CRUD efficiently and eventually reduce radiation exposure of personnel at nuclear power plant is suggested. This separator consists of inner and outer magnet assemblies, coolant channel and container surrounding the outer magnet assembly. The rotational motion of the inner and outer permanent magnet assemblies surrounding the coolant channel by driving motor system produces moving alternating magnetic fields in the coolant channel. The CRUD can be separated from the coolant by the moving alternating magnetic field. This study describes the results of preliminary experiment performed with the different flow rates of coolant and rotation velocities of magnet assemblies. This new magnetic filter shows better performance results of filtering the magnetite at coolant (water). Flow rates, rotating velocities of magnet assemblies and particle sizes turn out to be very important design parameters

  6. Legal consequences of nuclear accidents and shutdowns. Regulatory matters. Private litigation matters. Transcript of proceedings, held in Hershey, Pennsylvania, July 27-28, 1979

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    Four months after the Three Mile Island-2 accident, the Pennsylvania Law Journal assembled many of the most prominent attorneys with experience in nuclear power issues to discuss and explore some of the questions confronting lawyers and their clients affected by the nation's worst civilian nuclear accident. It is significant that the conference was held in Hershey, Pennsylvania, seven miles from Harrisburg, the State Capitol, and 15 miles from Three Mile Island. The conference focused on the legal issues, of rates, used and useful, and cost of replacement energy; and the litigation issues - extraordinary nuclear occurrence, theories of liability, and damages. The audience also had a need to discuss the future of Federal regulation as well as the issues of most immediate concern

  7. Procedures for analysis of accidents in shutdown modes for WWER nuclear power plants. A publication of the extrabudgetary programme on the safety of WWER and RBMK nuclear power plants

    International Nuclear Information System (INIS)

    1997-07-01

    Operational events occurring during shutdown conditions contribute significantly to the NPP risk due to the fact that both preventive and mitigatory capabilities of the plant are somehow degraded. The need for detailed information in the performance and review of accident analysis for WWER type NPPs was identified as a priority within IAEA Extrabudgetary Program on Safety of WWER and RBMK NPPs. The present guidelines were developed through two consultants meetings in 1995 and 1996. The guidelines establish a set of criteria for performing deterministic analysis of accidents, initiated by events occurring under shutdown conditions. This report is mostly relevant for licensing type calculations, and may to a certain extent, also used for development, improvement or justification of the plant limits and conditions, emergency operating procedures, operator training programs and probabilistic safety studies. The guidelines apply to all WWER plants in operation and/or under construction

  8. Backup passive reactivity shutdown systems

    International Nuclear Information System (INIS)

    Ashurko, Yu.M.; Kuznetsov, L.A.

    1996-01-01

    The paper reviews self-actuated shutdown systems (SASSs) for liquid metal-cooled fast reactors (LMFRs). Principles of operation are described, advantages and drawbacks analyzed, and prospects for application in advanced fast reactors examined. Ways to improve reactor self-protection via reactivity feedback amplification and related problems are discussed. (author). 9 refs, 12 figs

  9. Backup passive reactivity shutdown systems

    Energy Technology Data Exchange (ETDEWEB)

    Ashurko, Yu M; Kuznetsov, L A [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1996-12-01

    The paper reviews self-actuated shutdown systems (SASSs) for liquid metal-cooled fast reactors (LMFRs). Principles of operation are described, advantages and drawbacks analyzed, and prospects for application in advanced fast reactors examined. Ways to improve reactor self-protection via reactivity feedback amplification and related problems are discussed. (author). 9 refs, 12 figs.

  10. Elementary calculation of the shutdown delay of a pile

    International Nuclear Information System (INIS)

    Yvon, J.

    1949-04-01

    This study analyzes theoretically the progress of the shutdown of a nuclear pile (reactor) when a cadmium rod is introduced instantaneously. For simplification reasons, the environment of the pile is considered as homogenous and only thermal neutrons are considered (delayed neutrons are neglected). Calculation is made first for a plane configuration (plane vessel, plane multiplier without reflector, and plane multiplier with reflector), and then for a cylindrical configuration (multiplier without reflector, multiplier with infinitely thick reflector, finite cylindrical piles without reflector and with reflector). The self-sustain conditions are calculated for each case and the multiplication length and the shutdown delay are deduced. (J.S.)

  11. The Bulgaria before shut-down of next two blocks

    International Nuclear Information System (INIS)

    Dobak, D.

    2005-01-01

    The Ministry of Trade and Industry of United Kingdom in the frame of realization of programmes for the Middle and East Europe in the area of nuclear energetics during October 5 - 7, 2005 in Kozloduj has organized the Second International Conference on the theme 'Liquidation, social and economic changes'. In this paper author informs about Kozloduj NPP and plans for shut-down of this NPP as well as consequences of the shut-down. One of them the increase of unemployment and social impact for this region are presented

  12. Plant operational states analysis in low power and shutdown PSA

    International Nuclear Information System (INIS)

    He Jiandong; Qiu Yongping; Zhang Qinfang; An Hongzhen; Li Maolin

    2013-01-01

    The purpose of Plant Operational States (POS) analysis is to disperse the continuous and dynamic process of low power and shutdown operation, which is the basis of developing event tree models for accident sequence analysis. According to the design of a 300 MW Nuclear Power Plant Project, operating experience and procedures of the reference plant, a detailed POS analysis is carried out based on relative criteria. Then, several kinds of POS are obtained, and the duration of each POS is calculated according to the operation records of the reference plant. The POS analysis is an important element in low power and shutdown PSA. The methodology and contents provide reference for POS analysis. (authors)

  13. BWR shutdown analyzer using artificial intelligence (AI) techniques

    International Nuclear Information System (INIS)

    Cain, D.G.

    1986-01-01

    A prototype alarm system for detecting abnormal reactor shutdowns based on artificial intelligence technology is described. The system incorporates knowledge about Boiling Water Reactor (BWR) plant design and component behavior, as well as knowledge required to distinguish normal, abnormal, and ATWS accident conditions. The system was developed using a software tool environment for creating knowledge-based applications on a LISP machine. To facilitate prototype implementation and evaluation, a casual simulation of BWR shutdown sequences was developed and interfaced with the alarm system. An intelligent graphics interface for execution and control is described. System performance considerations and general observations relating to artificial intelligence application to nuclear power plant problems are provided

  14. Improvements in the nuclear power plants - a permanent task for the plant management

    International Nuclear Information System (INIS)

    Langetepe, G.

    1991-01-01

    The main motives of the operators of nuclear power plants for carrying out backfitting measures are given by the following objectives: (1) to operate the nuclear power plants, older ones too, at a high level of safety, and to keep a lowest possible difference to the respective level of science and technology, (2) to ensure preconditions for a best possible economical operation, also with changing cost structures, (3) to create preconditions for the longest possible operational time. Operational times of more than 40 years have been throught to be realistic. A constant analysis of the operational safety of the whole plant is necessary for laying down the measures for backfitting of the plant. This analysis must also include the valuation of the nuclear safety in accordance with the progressive level of sience and technology. The proccess of backfitting in the German nuclear power plants will be illustrated with the help of several examples. (orig.) [de

  15. Permanent radiation and weather monitoring systems at the Posiva nuclear waste facilities

    International Nuclear Information System (INIS)

    Laukkanen, J.; Palomaeki, M.; Viitanen, P.; Kumpula, L.

    2012-12-01

    Posiva Oy is planning to build a complex of two nuclear waste facilities in Olkiluoto. The facilities will encapsulate and dispose the spent nuclear fuel from the nuclear power plants operated by Posiva's owners into Olkiluoto bedrock. The spent fuel is strongly radioactive, so the radiation safety of the facilities and their processes for its users and the environment must be ensured. This paper deals with of the stationary radiation and weather measurement systems designed for the monitoring of Posiva's nuclear waste facilities and their processes. The systems are used for monitoring the encapsulation and disposal facilities and processes, as well as the emissions to the environment. The document collects also the system design basis and other requirements to be considered in the design of these systems at this early stage. (orig.)

  16. Control rod shutdown system

    International Nuclear Information System (INIS)

    Miyamoto, Yoshiyuki; Higashigawa, Yuichi.

    1996-01-01

    The present invention provides a control rod terminating system in a BWR type nuclear power plant, which stops an induction electric motor as rapidly as possible to terminate the control rods. Namely, the control rod stopping system controls reactor power by inserting/withdrawing control rods into a reactor by driving them by the induction electric motor. The system is provided with a control device for controlling the control rods and a control device for controlling the braking device. The control device outputs a braking operation signal for actuating the braking device during operation of the control rods to stop the operation of the control rods. Further, the braking device has at least two kinds of breaks, namely, a first and a second brakes. The two kinds of brakes are actuated by receiving the brake operation signals at different timings. The brake device is used also for keeping the control rods after the stopping. Even if a stopping torque of each of the breaks is small, different two kinds of brakes are operated at different timings thereby capable of obtaining a large stopping torque as a total. (I.S.)

  17. Permanently magnetized high gradient magnetic air filters for the nuclear industry

    International Nuclear Information System (INIS)

    Watson, J.H.P.

    1995-01-01

    This paper describes the structure and testing of two novel permanently magnetized magnetic filters for fine radioactive material. In the first filter the holes in the filter are left open as capture proceeds which means the pressure drop builds up only slowly. This filter is not suitable for composite particles which can be broken by mechanical forces. The second filter has been changed so as to strongly capture particles composed of fine particles weakly bound together which tend to break when captured. This uses a principle of assisted capture in which coarse particles aid the capture of the fine fragments. These filters have the following characteristics: (1) no external magnet is required, (2) no external power is required, (3) small in size and portable, (4) easily interchangeable, and (5) can be cleaned without demagnetizing by using a magnetic fluid which matches the susceptibility of the captured particles

  18. The Defense Science Board Permanent Task Force on Nuclear Weapons Surety. Report on the Unauthorized Movement of Nuclear Weapons

    National Research Council Canada - National Science Library

    Welch, Larry D; Agnew, Harold M; Bien, Lyle G; Crawford, John C; Foster, Jr., John S; Gold, Sydell P; McCarthy, James P; Mies, Richard W; Neary, Thomas H; Selden, Robert L

    2008-01-01

    ...]) and the Commander, U.S. Strategic Command to conduct an independent investigation of the unauthorized transfer of nuclear warheads between Minot Air Force Base, North Dakota, and Barksdale Air Force Base, Louisiana on 30 August 2007...

  19. Defence-in-depth strategy of fire protection and its relevance after final shutdown (by the example of Germany)

    Energy Technology Data Exchange (ETDEWEB)

    Beesen, Michael; Ernst, Benjamin; Fischer, Guenter [TUeV SUeD Industrie Service GmbH (Germany)

    2015-12-15

    Nuclear power plants (NPP) are protected against internal and external fires by a fire protection defence-in-depth concept including the following precautionary measures: operational, structural and equipment related fire protection measures as well as manual fire fighting. The fire protection measures are designed in consideration of fires to be expected (from fire loads permanently and temporarily present together with potential ignition sources) in order to prevent a violation of both the protection goals of public law and the nuclear protection goals / radiological safety objectives in case of internal and external fires. The aspect ''What is the future significance of the fire protection defence-in-depth concept?'' needs to be considered with regard to the situation following the final shutdown. From our point of view as a TSO (technical safety organization) both the non-nuclear protection goals (e.g. prevent occurrence of a fire; ensure escape and rescue of humans) as well as the nuclear ones have to be ensured after final shutdown of a nuclear plant. The protection goals of public law will almost completely remain after the plant has stopped commercial operation while the nuclear safety objectives will be stepwise reduced in consideration of the decommissioning status until the end of the nuclear supervision. Nevertheless, the fire protection concept must clearly specify those fire protection measures that are necessary to ensure the plants' safety. The situation on site regularly needs to be under examination to check if the fire protection concept covers all conditions to be considered and if the existing fire protection measures are sufficient or if an adaption is necessary.

  20. Decree no. 2002-447 of the 27 march 2002 authorizing the Normandy society of preserve and sterilization to realize definitive shutdowns and dismantling operations of the nuclear installation no. 152 situated on the territory of Osmanville (Calvados)

    International Nuclear Information System (INIS)

    2002-01-01

    The decree presents the shutdown preliminary obligations, the installation quality, the prevention of radioactivity dissemination risk, the workers protection, the wastes management, the fire prevention. (A.L.B.)

  1. The relationship between radiation load and chromosome aberrations in permanent staff of nuclear facilities

    International Nuclear Information System (INIS)

    Heubisch, W.

    1982-01-01

    Employees of nuclear power stations can be exposed to an increased risk. Using chromosome analytical methods an attempt is made to establish a dose-response relationship for relatively low radiation dose levels. Chromosome aberrations in lymphocytes at the stage of mitosis were classified according to morphological structure and gaps. Correlation and regression analysis produced a positive relationship compared to the previous year's dose and aberrations, whereas no dependence could be proved for the actual age dose and age. (DG) [de

  2. Shutdowns/scrams at BWRs reported under new 1984 LER rule

    International Nuclear Information System (INIS)

    Mays, G.T.

    1985-01-01

    Operating experience data from nuclear power plants are essential for safety and reliability analyses. The Licensee Event Reports (LERs), submitted to the NRC by nuclear power plant utilities, contain much of this data. One of the significant aspects of the new LER rule includes the requirement to report all plant shutdowns whereas prior to 1984, not all shutdowns were reported as LERs. This paper reviews the shutdowns and scrams occurring during the first six months of 1984 at BWRs as reported under the new LER rule. The review focused on systems involved, causes, and personnel interactions

  3. Magnetic latch trigger for inherent shutdown assembly

    International Nuclear Information System (INIS)

    Sowa, E.S.

    1976-01-01

    An inherent shutdown assembly for a nuclear reactor is provided. A neutron absorber is held ready to be inserted into the reactor core by a magnetic latch. The latch includes a magnet whose lines of force are linked by a yoke of material whose Curie point is at the critical temperature of the reactor at which the neutron absorber is to be inserted into the reactor core. The yoke is in contact with the core coolant or fissionable material so that when the coolant or the fissionable material increase in temperature above the Curie point the yoke loses its magnetic susceptibility and the magnetic link is broken, thereby causing the absorber to be released into the reactor core. 6 claims, 3 figures

  4. Communication received from the permanent mission of the Argentine Republic regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    1994-11-01

    On 11 May 1994, the Director General received a note verbale from the Permanent Mission of Argentina to the International Atomic Energy Agency relating to the export of nuclear material, equipment and technology. The purpose of this note verbale is to provide further information on the nuclear export policies and practices of the Government of the Argentine Republic. In the light of the wish expressed at the end of the note verbale, the text of the note verbale is annexed hereto

  5. Communication received from the permanent mission of the Argentine Republic regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    1994-11-01

    On 11 May 1994, the Director General received a note verbale from the Permanent Mission of Argentina to the International Atomic Energy Agency relating to the export of nuclear material, equipment and technology. The purpose of this note verbale is to provide further information on nuclear export policies and practices of the Government of the Argentine Republic. In the light of the wish expressed at the end of the note verbale, the text of the note verbale is annexed hereto

  6. Communication of 10 December 2003 from the Permanent Mission of the People's Republic of China to the International Atomic Energy Agency regarding China's nuclear policies and practices

    International Nuclear Information System (INIS)

    2004-01-01

    The Director General has received a letter of 10 December 2003 from the Permanent Mission of the People's Republic of China providing a White Paper on the nuclear non-proliferation policy and measures of the People's Republic of China. In light of the wish expressed in the penultimate paragraph, the letter and the White Paper are attached hereto

  7. Communication Received from the Permanent Mission of Pakistan to the International Atomic Energy Agency Concerning the Promulgation of the Pakistan Nuclear Regulatory Authority Ordinance 2001

    International Nuclear Information System (INIS)

    2001-01-01

    The Director General has received a communication dated 30 January 2001 from the Permanent Mission of Pakistan forwarding a press release concerning the promulgation of the Pakistan Nuclear Regulatory Authority Ordinance 2001. As requested in that communication, the press release is attached hereto for the information of Member States

  8. Communication from the Permanent Mission of Finland to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    2000-01-01

    The document reproduces the text of the Note Verbale received by the Director General of the IAEA from the Permanent Mission of Finland providing information on the export policies and practices of the Government of Finland with respect to the export of nuclear material, equipment and technology

  9. Communication of 20 October 2003 from the Permanent Mission of the Republic of Estonia to the International Atomic Energy Agency regarding Estonia's nuclear policies and practices

    International Nuclear Information System (INIS)

    2004-01-01

    The Director General has received a Note Verbale of 20 October 2003 from the Permanent Mission of the Republic of Estonia providing information about the nuclear policies and practices of the Republic of Estonia. In light of the wish expressed in the Note Verbale, its text is attached hereto

  10. Communication dated 2 March 2007 from the Permanent Mission of the Islamic Republic of Iran to the Agency concerning the nuclear activities of Iran

    International Nuclear Information System (INIS)

    2007-01-01

    The Secretariat has received a Note Verbale dated 2 March 2007 from the Permanent Mission of the Islamic Republic of Iran (Iran), attaching a letter dated 19 February 2007 addressed to the Director General from the Resident Representative of Iran concerning the nuclear activities of Iran. The Note Verbale and, as requested therein, its attachment, are circulated herewith

  11. Communication from the Permanent Mission of Australia to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    2000-01-01

    The document reproduces the text of the Note Verbale received by the Director General of the IAEA from the Permanent Mission of Australia providing information on the export policies and practices of the Government of Australia with respect to the export of nuclear material, equipment and technology

  12. Communication dated 18 May 2009 received from the Permanent Mission of Kazakhstan to the Agency enclosing a position paper regarding the establishment of IAEA nuclear fuel banks

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a communication dated 18 May 2009 from the Permanent Mission of Kazakhstan, transmitting a position paper of Kazakhstan regarding the establishment of IAEA nuclear fuel banks. As requested in that communication, the attached position paper is herewith circulated for the information of all Member States

  13. Communication of 26 January 2004 from the Permanent Mission of the People's Republic of China to the International Atomic Energy Agency regarding China's nuclear policies and practices

    International Nuclear Information System (INIS)

    2004-01-01

    The Director General has received a Note Verbale dated 26 January 2004 from the Permanent Mission of the People's Republic of China regarding China's nuclear policies and practices. In the light of the wish expressed in the penultimate paragraph, the Note Verbale is attached hereto

  14. Communication from the Permanent Mission of France to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    2000-01-01

    The document reproduces the text of the Note Verbale received by the Director General of the IAEA from the Permanent Mission of France to the IAEA providing information on the policies and practices of the Government of France with respect to the export of nuclear material, equipment and technology

  15. Communication received from the Permanent Mission of Thailand regarding the Treaty on the Southeast Asia Nuclear Weapon-Free Zone (Treaty of Bangkok)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-04

    The document reproduces the text of the Note Verbale dated 25 September 1997 received by the Agency from the Permanent Mission of Thailand to the Agency concerning the Treaty on the Southeast Asia Nuclear Weapon-Free Zone (Treaty of Bangkok), and as attachment the text of the above mentioned Treaty

  16. Communication received from the Permanent Mission of Thailand regarding the Treaty on the Southeast Asia Nuclear Weapon-Free Zone (Treaty of Bangkok)

    International Nuclear Information System (INIS)

    1998-01-01

    The document reproduces the text of the Note Verbale dated 25 September 1997 received by the Agency from the Permanent Mission of Thailand to the Agency concerning the Treaty on the Southeast Asia Nuclear Weapon-Free Zone (Treaty of Bangkok), and as attachment the text of the above mentioned Treaty

  17. Communication of 22 March 2002 from the Permanent Mission of the Republic of Kazakhstan to the International Atomic Energy Agency regarding Kazakhstan's nuclear policies and practices

    International Nuclear Information System (INIS)

    2002-01-01

    The Director General has received a note verbale of 22 March 2002 from the Permanent Mission of the Republic of Kazakhstan providing information about the nuclear policies and practices of the Republic of Kazakhstan. In the light of the wish expressed in the note verbale, its text is attached hereto

  18. Oak Ridge Research Reactor shutdown maintenance and surveillance

    International Nuclear Information System (INIS)

    Coleman, G.H.; Laughlin, D.L.

    1990-10-01

    The Department of Energy ordered the Oak Ridge Research Center Reactor to be placed in permanent shutdown on July 14, 1987. Maintenance activities, both mechanical and instrument, were essentially routine in nature. The performance of the instrumentation for the facility was satisfactory, and maintenance required is provided. The performance of the process system was satisfactory, and maintenance required is indicated. The results of efficiency tests of the various gaseous-waste filters have been summarized and preparations for transfer of the facility to the remedial action program is also indicated

  19. Seismic qualification of SPX1 shutdown systems - tests and calculations

    International Nuclear Information System (INIS)

    Brochard, D.; Buland, P.

    1988-01-01

    The SUPERPHENIX 1 shutdown system is composed of two main systems: the Complementary Shutdown System SAC (Systeme d'Arret Complementaire) and the Primary Shutdown System (SCP) (Systeme de Commande Principal). In case of a seismic event, the insertability of the different shutdown systems has to be demonstrated. Tests have been performed on the SAC and have shown that this system was not sensitive to the seismic excitation (the drop time increases of 10% at SSE level). For the SCP, as an analytical demonstration was felt difficult to achieve, it was decided to perform a full scale testing program. These tests have been performed for the two types of SCP which are present in Superphenix: SCP 1 (Creusot Loire design), SCP 2 (Novatome design). As there was no existing facility in France to test this kind of slender structure (21 metres high) a new facility named VESUBIE was designed and installed in an existing pit located at the Saclay nuclear research center. The objectives of the tests were the following: to demonstrate insertability of control rod; to demonstrate absence of seismic induced damage to the SCP; to measure increase of scram time; to measure seismic induced stresses; to obtain data for code correlation. After completion of the tests, measurements have been correlated with results obtained from a non-linear finite element model. Time history correlations were achieved for SCP 1. Afterwards a calculation was performed in hot condition to find if there was some effect of temperature on SCP seismic response. 2 refs, 8 figs

  20. Causes of extended shutdown state of 'RA' research reactor in Vinca Institute

    International Nuclear Information System (INIS)

    Pesic, M.; Kolundzija, V.; Ljubenov, V.; Cupac, S.

    2001-01-01

    This paper describes the causes and reasons for extended shutdown state of RA research reactor in the 'Vinca' Institute of Nuclear Sciences. Technical and legal matters that led to decision to stop RA reactor operation in 1984 and further problems related to maintenance and preparation for continuation of operation are given. Influence of nuclear policy of Yugoslav government and the 'Vinca' Institute at prolongation of the reactor shutdown state, as consequence of changing of nuclear programme in the country and the world are discussed and underlined. An overview of the legislation in the field of nuclear safety and regulatory control of radiation sources and radioactive materials in Yugoslavia is presented. (author)

  1. Multi-unit shutdown due to boiler feedwater chemical excursion

    International Nuclear Information System (INIS)

    Diebel, M.E.

    1991-01-01

    Ontario Hydro's Bruce Nuclear Generating Station 'B' consists of four 935 W CANDU units located on the east shore of Lake Huron in the province of Ontario, Canada. On July 25 and 26, 1989 three of the four operating units were shutdown due to boiler feedwater chemical excursions initiated by a process upset in the Water Treatment Plant that provides demineralized make-up water to all four units. The chemicals that escaped from an ion exchange vessel during a routine regeneration very quickly spread through the condensate make-up system and into the boiler feedwater systems. This resulted in boiler sulfate levels exceeding shutdown limits. A total of 260 GWH of electrical generation was unexpectedly made unavailable to the grid at a time of peak seasonal demand. This event exposed several unforeseen deficiencies and vulnerabilities in the automatic demineralized water make-up quality protection scheme, system designs, operating procedures and the ability of operating personnel to recognize and appropriately respond to such an event. The combination of these factors contributed towards turning a minor system upset into a major multi-unit shutdown. This paper provides the details of the actual event initiation in the Water Treatment Plant and describes the sequence of events that led to the eventual shutdown of three units and near shutdown of the fourth. The design inadequacies, procedural deficiencies and operating personnel responses and difficulties are described. The process of recovering from this event, the flushing out of system piping, boilers and the feedwater train is covered as well as our experiences with setting up supplemental demineralized water supplies including trucking in water and the use of rental trailer mounted demineralizing systems. System design, procedural and operational changes that have been made and that are still being worked on in response to this event are described. The latest evidence of the effect of this event on boiler tube

  2. Simulation of a hypothetical liquid relief valve failure (open) at Embalse nuclear power plant when a reactor shutdown is considered; Simulacion de la evolucion de la CNE (central nuclear Embalse) en el caso hipotetico de la apertura espuria de una valvula de alivio liquido con disparo del reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bedrossian, G; Gersberg, S [Comision Nacional de Energia Atomica, San Martin (Argentina). Unidad de Actividad Reactores y Centrales Nucleares

    1997-12-31

    The study of the spurious opening of the liquid relief valves is of great interest in CANDU nuclear power plants because this could lead to a loss of coolant through the degasser-condenser relief valves, and implies an undesirable intermittent opening/closure of them. In fact, there is a specific procedure to follow at Embalse nuclear power plant whenever this abnormal situation occurs. This procedure contains a section where a reactor trip is considered. Really, automatic reactor trip is not accepted to occur. No trip parameters set points are through to be reached (neutronic or process). However, the procedure considers the situation where the reactor does trip. We analyzed the plant behavior when a reactor shutdown is triggered. Our objective was to assess if after this trip, the procedure can lead the plant to a safe situation, preventing high pressures in the degasser-condenser and with the inventory recovered in the storage tank. The case was analyzed with Firebird III, Mod. 1.0 code. Two situations were considered: trip at 40 sec. and trip at 180 sec. after the liquid relief valve failed opened (the latter when the degasser-condenser fills up). Procedure analysis and code simulations showed that following the steps recommended, provided the liquid relief valve can be closed manually, the inventory that enters the degasser-condenser from the heat transport primary system through the failed valve could be recovered in the storage tank, leading the plant to shutdown in safe conditions, and preventing the degasser-condenser relief valves setpoint from being reached. (author). 3 refs., 10 figs.

  3. Communication dated 26 May 2009 received from the Permanent Mission of Austria to the Agency enclosing a working paper regarding Multilateralisation of the Nuclear Fuel Cycle

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a communication dated 26 May 2009 from the Permanent Mission of Austria, transmitting a working paper entitled 'Multilateralisation of the Nuclear Fuel Cycle: Increasing Transparency and Sustainable Security'. The working paper is based on a food-for-thought paper previously submitted by Austria on 10 May 2007, and issued as INFCIRC/706. As requested in that communication, the working paper is herewith circulated for the information of all Member States

  4. Communication from the Permanent Mission of Cyprus to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    2001-01-01

    The Director General of the International Atomic Energy Agency has received a Note Verbale from the Permanent Mission of Cyprus providing information on the export policies and practices of the Government of Cyprus with respect to the export of nuclear material, equipment and technology. In the light of the wish expressed at the end of the Note Verbale, the text of the Note Verbale is attached. The attachment to the Note Verbale was issued previously as INFCIRC/254/Rev. 4/Part 1

  5. Text of communication of 14 November 2000 received from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency concerning nuclear disarmament

    International Nuclear Information System (INIS)

    2000-01-01

    The Director General has received a communication dated 14 November 2000 from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency concerning nuclear disarmament, attaching a statement by the President of the Russian Federation. The text of the communication and, as requested therein, the text of the President of the Russian Federation, are attached hereto for the information of Member States

  6. Communication from the Permanent Missions of the Russian Federation and the United States of America regarding a joint statement on nuclear cooperation

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a communication from the Permanent Missions of the Russian Federation and the United States of America, transmitting the text of the Joint Statement by the Presidents of the Russian Federation and the United States of America on Nuclear Cooperation issued on 6 July 2009 in Moscow. As requested in that communication, the abovementioned statement is herewith circulated for the information of all Member States

  7. Communication dated 23 June 2009 received from the Permanent Mission of the United States of America with regard to Global Initiative to Combat Nuclear Terrorism Plenary Meeting

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a communication dated 23 June 2009 from the Permanent Mission of the United States of America transmitting the 16 June 2009 message from President Barack Obama to the Global Initiative to Combat Nuclear Terrorism (GICNT) Plenary Meeting held in the Hague on 16-17 June 2009. As requested in that communication, the abovementioned message is herewith circulated for the information of all Member States

  8. Maintenance, repair and operation (MRO) of shutdown facilities

    International Nuclear Information System (INIS)

    Kenny, S.

    2006-01-01

    What level of maintenance does one apply to a shutdown facility? Well it depends on who you ask. Operations staff sees facilities that have completed their useful life cycle as a cost drain while Decommissioning staff sees this as the start of a new life cycle. Based on the decommissioning plan for the particular facility the building could complete another full life cycle while under decommissioning whether it is in storage with surveillance mode or under active decommissioning. This paper will explore how you maintain a facility and systems for many years after its useful life until final decommissioning is completed. When a building is declared redundant, who looks after it until the final decommissioning end state is achieved? At the AECL, Chalk River Labs site the safe shutdown and turnover process is one key element that initiates the decommissioning process. The real trick is orchestrating maintenance, repair and operation plans for a facility that has been poorly invested in during its last years of useful life cycle. To add to that usually shutdowns are prolonged for many years beyond the expected turnover period. During this presentation I will cover what AECL is doing to ensure that the facilities are maintained in a proper state until final decommissioning can be completed. All facilities or systems travel through the same life cycle, design, construction, commissioning, operation, shutdown and demolition. As we all know, nuclear facilities add one more interesting twist to this life cycle called Decommissioning that lands between shutdown and demolition. As a facility nears the shutdown phase, operations staff loose interest in the facility and stop investing in upgrades, repairs and maintenance but continue to invest and focus on maximizing operations. Facility maintenance standards produced by the International Facility Maintenance Association (IFMA) based on a survey done every year state that 2.2% of the total operating costs for the site should be

  9. Communication received from the permanent mission of Austria regarding the provision of certain additional information on production, inventories and international transfers of nuclear material and on exports of certain relevant equipment and non-nuclear material

    International Nuclear Information System (INIS)

    1996-01-01

    The Director General received a note verbale of 13 June 1996 from Permanent Mission of Austria regarding the provision of certain additional information on production, inventories and international transfers of nuclear material and on exports of certain relevant equipment and non-nuclear material. In the light of the request expressed at the end of the note verbale, the text of the note verbale is being circulated

  10. Communication received from the Permanent Mission of Sweden regarding the provision of certain additional information on production, inventories and international transfers of nuclear material and on exports of certain relevant equipment and non-nuclear material

    International Nuclear Information System (INIS)

    1996-01-01

    The document reproduces the text of a note verbale dated 28 June 1996 received by the Director General of IAEA from the Permanent Mission of Sweden through which the Government of Sweden provides, on a voluntary basis, certain additional information on production, inventories and international transfers of nuclear material and on exports of certain relevant equipment and non-nuclear material, in order to assist the Agency in the discharge of its safeguards responsibilities

  11. Communication received from the permanent mission of Finland regarding the provision of certain additional information on production, inventories and international transfers of nuclear material and on exports of certain relevant equipment and non-nuclear material

    International Nuclear Information System (INIS)

    1996-01-01

    The Director General received a note verbale of 8 February 1996 from Permanent Mission of Finland regarding the provision of certain additional information on production, inventories and international transfers of nuclear material and on exports of certain relevant equipment and non-nuclear material. In the light of the request expressed at the and of the note verbale, the text of the note verbale is being circulated

  12. Shutdown Chemistry Process Development for PWR Primary System

    Energy Technology Data Exchange (ETDEWEB)

    Sung, K.B. [Korea Electric Power Research Institute, Taejeon (Korea, Republic of)

    1997-12-31

    This study report presents the shutdown chemistry of PWR primary system to reduce and remove the radioactive corrosion products which were deposited on the nuclear fuel rods surface and the outside of core like steam generator channel head, RCS pipings etc. The major research results are the follows ; the deposition radioactive mechanism of corrosion products, the radiochemical composition, the condition of coolant chemistry to promote the dissolution of radioactive cobalt and nickel ferrite, the control method of dissolved hydrogen concentration in the coolant by the mechanical and chemical methods. The another part of study is to investigate the removal characteristics of corrosion product ions and particles by the demineralization system to suggest the method which the system could be operate effectively in shut-down purification period. (author). 19 refs., 25 figs., 48 tabs.

  13. 235U Holdup Measurement Program in support of facility shutdown

    International Nuclear Information System (INIS)

    Thomason, R.S.; Griffin, J.C.; Lien, O.G.; McElroy, R.D.

    1991-01-01

    In 1989, the Department of Energy directed shutdown of an enriched uranium processing facility at Savannah River Site. As part of the shutdown requirements, deinventory and cleanout of process equipment and nondestructive measurement of the remaining 235 U holdup were required. The holdup measurements had safeguards, accountability, and nuclear criticality safety significance; therefore, a technically defensible and well-documented holdup measurement program was needed. Appropriate standards were fabricated, measurement techniques were selected, and an aggressive schedule was followed. Early in the program, offsite experts reviewed the measurement program, and their recommendations were adopted. Contact and far-field methods were used for most measurements, but some process equipment required special attention. All holdup measurements were documented, and each report was subjected to internal peer review. Some measured values were checked against values obtained by other methods; agreement was generally good

  14. Communication dated 30 May 2014 received from the Permanent Mission of Uzbekistan to the Agency regarding the implementation of the initiative of the President of Uzbekistan on Establishing a Nuclear-Weapon-Free Zone in Central Asia

    International Nuclear Information System (INIS)

    2014-01-01

    The Director General has received a note verbale dated 30 May 2014 from the Permanent Mission of Uzbekistan to the Agency regarding the implementation of the initiative of the President of Uzbekistan, HE Mr Islam Karimov, on Establishing a Nuclear-Weapon-Free Zone in Central Asia. The note verbale and its attachment are circulated herewith for information, as requested by the Permanent Mission

  15. Technical Specification action statements requiring shutdown

    International Nuclear Information System (INIS)

    Mankamo, T.; Kim, I.S.; Samanta, P.K.

    1993-11-01

    When safety systems fail during power operation, the limiting conditions for operation (LCOs) and associated action statements of technical specifications typically require that the plant be shut down within the limits of allowed outage time (AOT). However, when a system needed to remove decay heat, such as the residual heat removal (RHR) system, is inoperable or degraded, shutting down the plant may not necessarily be preferable, from a risk perspective, to continuing power operation over a usual repair time, giving priority to the repairs. The risk impact of the basic operational alternatives, i.e., continued operation or shutdown, was evaluated for failures in the RHR and standby service water (SSW) systems of a boiling-water reactor (BWR) nuclear power plant. A complete or partial failure of the SSW system fails or degrades not only the RHR system but other front-line safety systems supported by the SSW system. This report presents the methodology to evaluate the risk impact of LCOs and associated AOT; the results of risk evaluation from its application to the RHR and SSW systems of a BWR; the findings from the risk-sensitivity analyses to identify alternative operational policies; and the major insights and recommendations to improve the technical specifications action statements

  16. Reactor shutdown back-up system

    International Nuclear Information System (INIS)

    Hirao, Seizo; Sakashita, Motoaki.

    1982-01-01

    Purpose: To prevent back flow of poison upon injection to a moderator recycling pipeway. Constitution: In a nuclear reactor comprising a moderator recycling system for recycling and cooling moderator through a control rod guide pipe and a rapid poison injection system for rapidly injecting a poison solution at high density into the moderator by way of the same control rod guide pipe as a reactor shutdown back-up system, a mechanism is provided for preventing the back flow of a poison solution at high density into the moderator recycling system upon rapid injection of poison. An orifice provided in the joining pipeway to the control rod guide pipe on the side of the moderator recycling system is utilized as the back flow preventing device for the poison solution and the diameter for the orifice is determined so as to provide a constant ratio between the pressure loss in the control rod guide pipe and the pressure loss in the moderator recycling system pipe line upon usual reactor operation. (Kawakami, Y.)

  17. Reactor shut-down device

    International Nuclear Information System (INIS)

    Otsuka, Fumio; Horikawa, Yuji.

    1990-01-01

    The present invention concerns an externally disposed reactor shut-down device for an FBR type reactor using liquid sodium as coolants. An introducing pipe having an outlet port disposed at an upper portion thereof is disposed at a lower end of an upper guide tube. An extension tube, an L-shaped measuring wire support and a measuring wire are disposed at the inside of the guide tube. With such a constitution, low temperature coolants flown out from the lower guide tube of a control rod and a great amount of high temperature coolants flown out from the lower guide tube of a fuel assembly are introduced smoothly to the introducing tube having the measuring wire support disposed therein. Accordingly, the high temperature coolants can be prevented from flowing out to the outside of the introducing tube and coolants after mixing can be flown and hit against a curie point electromagnet efficiently. This can make the response to abnormal temperature rise of coolants satisfactory and can provide reliable reactor scram. (I.N.)

  18. Design philosophy of PFBR shutdown systems

    International Nuclear Information System (INIS)

    Rajan Babu, V.; Vijayashree, R.; Govindarajan, S.; Vaidyanathan, G.; Muralikrishna, G.; Shanmugam, T.K.; Chetal, S.C.; Raghavan, K.; Bhoje, S.B.

    1996-01-01

    This paper presents the overall design philosophy of shutdown system of 500 MWe Prototype Fast Breeder Reactor (PFBR). It discusses design criteria, parameters calling for safety action, different safety actions and the concepts conceived for shutdown systems. In tune with the philosophy of defence-in-depth, additional passive shutdown features, viz., Self Actuating Device (SADE) and Curie Point Magnetic (CPM) switch and protective feature like absorber rod Stroke Limiting Device (SLD) are contemplated. It also discusses about suitability of Gas Expansion Module (GEM) as one of the safety devices in PFBR. (author). 3 refs, 3 figs, 1 tab

  19. Post Fire Safe Shutdown Analysis Using a Fault Tree Logic Model

    International Nuclear Information System (INIS)

    Yim, Hyun Tae; Park, Jun Hyun

    2005-01-01

    Every nuclear power plant should have its own fire hazard analysis including the fire safe shutdown analysis. A safe shutdown (SSD) analysis is performed to demonstrate the capability of the plant to safely shut down for a fire in any given area. The basic assumption is that there will be fire damage to all cables and equipment located within a common fire area. When evaluating the SSD capabilities of the plant, based on a review of the systems, equipment and cables within each fire area, it should be determined which shutdown paths are either unaffected or least impacted by a postulated fire within the fire area. Instead of seeking a success path for safe shutdown given all cables and equipment damaged by a fire, there can be an alternative approach to determine the SSD capability: fault tree analysis. This paper introduces the methodology for fire SSD analysis using a fault tree logic model

  20. Updating of the program for simulation of Darlington shutdown and regulation systems

    International Nuclear Information System (INIS)

    1988-07-01

    This report describes the current status of the developments of a simulation of the Darlington Nuclear Generating Station shutdown and regulating systems, DARSIM done under contract to the Atomic Energy Control Board (AECB). The DARSIM program simulates the spatial neutron dynamics, the regulation of the reactor power, and shutdown system 1 and shutdown system 2 software. The DARSIM program operates in the interactive simulation program environment. DARSIM was installed on the APOLLO computer at the AECB and a version for an IBM-PC was also provided for the exclusive use of the AECB. Shutdown system software was updated to incorporate the latest revisions in the functional specifications. Additional developments have been provided to assist in the use and interpretation of the DARSIM results

  1. Comparison of Qualitative and Quantitative Risk Results for Shutdown Operation

    International Nuclear Information System (INIS)

    Oh, Hae Cheol; Kim, Myung Ki; Chung, Bag Soon; Seo, Mi Ro; Hong, Sung Yull

    2006-01-01

    The Defense-In-Depth philosophy is a fundamental concept of nuclear safety. The objective of Defense-In- Depth (DID) evaluation is to assess the level of Defense- In-Depth maintained during the various plant maintenance activities. Especially for shutdown and outage operations, the Defense-In-Depth might be challenged due to the reduction in redundancy and diversity resulting from the maintenance. The qualitative defense-in-depth evaluation using deterministic trees such as SFAT (Safety Function Assessment Tree), can provide 'Safety' related information on the levels of defense-in-depth according to the plant configuration including the levels of redundancy and diversity. For the more reasonable color decision of SFAT, it is necessary to identify the risk impact of degradation of redundancy and diversity of mitigation systems. The probabilistic safety analysis for the shutdown status can provide risk information related on the degradation of redundancy and diversity level for the safety functions during outage. Insights from the both methods for the plant status can be the same or different. The results of DID approach and PSA for the shutdown state are compared in this paper

  2. Risks Associated with Shutdown in PWRs

    International Nuclear Information System (INIS)

    Grlicarev, I.

    1996-01-01

    The selected set of risks associated with reactor shutdown in PWRs are outlined and discussed (e. g. outage planning, residual heat removal capability, rapid boron dilution, containment integrity, fire protection). The contribution of different outage strategies to overall core damage risk during shutdown is assessed for a particular basic outage plan. The factors which increase or minimize the probability of reactor coolant boiling or core damage are analysed. (author)

  3. Current status of geotechnical research on the long-term safety of permanent repositories for nuclear waste

    International Nuclear Information System (INIS)

    Langer, M.

    1988-01-01

    The planned permanent underground repository for non-heat-generating wastes in the former Konrad iron-ore mine is now in the final stages of the plan approval procedures. The deadline for the final stages of the plan approval procedures for the Gorleben salt dome is approaching. It is time to give an account of what has been accomplished in the geotechnical field. The BGR has developed a complex geotechnical stability analysis that takes into account the requirements of permanent storage and the objectives required for the protection of the biosphere. This stability analysis is based on the following considerations: Owing to the complexity of the boundary conditions, a cavity intended for a permanent repository can be demonstrated to be safe only by a combination of studies and simulations. These studies must integrate engineering geology, geotechnics, rock mechanics, statics, monitoring of the conditions in the repository, and mining expertise. (orig.) With 27 figs

  4. ORNL Isotopes Facilities Shutdown Program Plan

    International Nuclear Information System (INIS)

    Gibson, S.M.; Patton, B.D.; Sears, M.B.

    1990-10-01

    This plan presents the results of a technical and economic assessment for shutdown of the Oak Ridge National Laboratory (ORNL) isotopes production and distribution facilities. On December 11, 1989, the Department of Energy (DOE), Headquarters, in a memorandum addressed to DOE Oak Ridge Operations Office (DOE-ORO), gave instructions to prepare the ORNL isotopes production and distribution facilities, with the exception of immediate facility needs for krypton-85, tritium, and yttrium-90, for safe shutdown. In response to the memorandum, ORNL identified 17 facilities for shutdown. Each of these facilities is located within the ORNL complex with the exception of Building 9204-3, which is located at the Y-12 Weapons Production Plant. These facilities have been used extensively for the production of radioactive materials by the DOE Isotopes Program. They currently house a large inventory of radioactive materials. Over the years, these aging facilities have inherited the problems associated with storing and processing highly radioactive materials (i.e., facilities' materials degradation and contamination). During FY 1990, ORNL is addressing the requirements for placing these facilities into safe shutdown while maintaining the facilities under the existing maintenance and surveillance plan. The day-to-day operations associated with the surveillance and maintenance of a facility include building checks to ensure that building parameters are meeting the required operational safety requirements, performance of contamination control measures, and preventative maintenance on the facility and facility equipment. Shutdown implementation will begin in FY 1993, and shutdown completion will occur by the end of FY 1994

  5. Proceedings of workshop on reactor shutdown system

    International Nuclear Information System (INIS)

    1997-03-01

    India has gained considerable experience in design, development, construction and operation of research and power reactors during the last four decades. Reactor shutdown system (RSS) is the most important engineered safety system of any reactor. A lot of technological developments have taken place to improve the reactor shutdown systems, particularly with advancement in reliability analysis and instrumentation and control. If the reactor is not shutdown, the fuel may melt, releasing radioactivity and possibly reactivity addition as in the case of Fast Breeder Reactor (FBR). Apart from radiological safety consequences, large investment has to be written off. The function of the RSS is to stop fission chain reaction and prevent breach of fuel. The design of RSS is multidisciplinary. It requires reactor physics analysis, design of absorber rods, drive mechanisms, safety logic to order shutdown and instrumentation to detect unsafe conditions. High reliability is essential and this requires two independent shutdown systems. This book contains the proceedings of the workshop on reactor shutdown system and papers relevant to INIS are indexed separately

  6. Nuclear topics

    International Nuclear Information System (INIS)

    Lukner, C.

    1982-07-01

    The pamphlet touches on all aspects of nuclear energy, from the world energy demands and consumption, the energy program of the Federal Government, nuclear power plants in the world, nuclear fusion, nuclear liability up to the nuclear fuel cycle and the shutdown of nuclear power plants. (HSCH) [de

  7. Communication from the Permanent Mission of Australia to the International Atomic Energy Agency regarding Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2002-01-01

    The Director General of the International Atomic Energy Agency has received a Note Verbale from the Permanent Mission of Australia, dated 31 August 2001, providing information on the export policies and practices of the Government of Australia with respect to the export of nuclear material, equipment and technology. In the light of the wish expressed at the end of the Note Verbale, the text of the Note Verbale is attached. The attachment referenced in the Note Verbale was issued previously as INFCIRC/254/Rev. 5/Part 1

  8. Optimization of reactor coolant shutdown chemistry practices for crud inventory management

    International Nuclear Information System (INIS)

    Fellers, B.; Barnette, J.; Stevens, J.; Perkins, D.

    2002-01-01

    This report describes reactor coolant shutdown chemistry control practices at Comanche Peak Steam Electric Station (CPSES, TXU-Generation, USA). The shutdown evolution is managed from a process control perspective to achieve conditions most favorable to crud decomposition and to avoiding re-precipitation of metals. The report discusses the evolution of current industry practices and the necessity for greater emphasis on shutdown chemistry control in response to Axial Offset Anomaly and growth of ex-core radiation fields during outage conditions. Nuclear Industry experience with axial offset anomaly (AOA), radiation field growth and unexpected behavior of crud during reactor shutdowns has encouraged the refinement of chemistry control practices during plant shutdown and startup. The strong implication of nickel rich crud as a cause of AOA and unexpected crud behavior has resulted in a focus on nickel inventory management. The goals for Comanche Peak Steam Electric Station (CPSES) include maintaining solubility of metals and radioisotopes, maximizing nickel removal and effective cleanup with demineralizers. This paper provides results and lessons learned from long term efforts to optimize the shutdown process. (authors)

  9. Nuclear instrumentation system operating experience and nuclear instrument testing in the EBR-II

    International Nuclear Information System (INIS)

    Yingling, G.E.; Curran, R.N.

    1980-01-01

    In March of 1972 three wide range nuclear channels were purchased from Gulf Atomics Corporation and installed in EBR-II as a test. The three channels were operated as a test until April 1975 when they became a permanent part of the reactor shutdown system. Also described are the activities involved in evaluating and qualifying neutron detectors for LMFBR applications. Included are descriptions of the ANL Components Technology Division Test Program and the EBR-II Nuclear Instrument Test Facilities (NITF) used for the in-reactor testing and a summary of program test results from EBR-II

  10. Chronology of the beryllium replacement shutdown at the High Flux Isotope Reactor (HFIR), 1983

    International Nuclear Information System (INIS)

    Kohring, M.W.

    1984-04-01

    In addition to the permanent beryllium reflector, several other components were replaced. The outer shroud and lower tracks were replaced. The new control rod access plugs and the upper tracks were installed. Replacement of collimator tubes for HB-1 and -2 are tentatively slated for the next permanent beryllium changeout. Inspection of the reactor vessel, the vessel-to-nozzle welds, core support structure, and vessel internal cladding showed them to be in acceptable condition. The highest, accumulative radiation doses received by Reactor Operations personnel during the shutdown, in mrem, were 665, 606, and 560; the highest for P and E personnel were 520, 505, and 475

  11. Communication Received from the Permanent Mission of the Netherlands regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2011-12-01

    The Agency has received a Note Verbale from the Permanent Mission of the Kingdom of the Netherlands, dated 12 July 2011, in which it requests that the Agency circulate to all Member States a letter of 12 July 2011 from the Chairman of the Nuclear Suppliers Group, Ambassador Piet de Klerk, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments' Guidelines for Nuclear Transfers [es

  12. Communication Received from the Permanent Mission of Brazil regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2008-01-01

    The Agency has received a Note Verbale from the Permanent Mission of Brazil, dated 22 March 2007, in which it requests that the Agency circulate to all Member States a letter of 12 December 2006 from the Chairman of the Nuclear Suppliers Group, Ambassador Jose Artur Denot Medeiros, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxemburg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments' Guidelines for Nuclear Transfers [es

  13. Communication Received from the Permanent Mission of the Netherlands regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2011-01-01

    The Agency has received a Note Verbale from the Permanent Mission of the Kingdom of the Netherlands, dated 12 July 2011, in which it requests that the Agency circulate to all Member States a letter of 12 July 2011 from the Chairman of the Nuclear Suppliers Group, Ambassador Piet de Klerk, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments' Guidelines for Nuclear Transfers

  14. Communication Received from the Permanent Mission of Brazil regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2007-01-01

    The Agency has received a Note Verbale from the Permanent Mission of Brazil, dated 22 March 2007, in which it requests that the Agency circulate to all Member States a letter of 12 December 2006 from the Chairman of the Nuclear Suppliers Group, Ambassador Jose Artur Denot Medeiros, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxemburg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments' Guidelines for Nuclear Transfers

  15. Improvements of primary coolant shutdown chemistry and reactor coolant system cleanup

    International Nuclear Information System (INIS)

    Gaudard, G.; Gilles, B.; Mesnage, F.; Cattant, F.

    2002-01-01

    In the framework of a radiation exposure management program entitled >, EDF aims at decreasing the mass dosimetry of nuclear power plants workers. So, the annual dose per unit, which has improved from 2.44 m.Sv in 1991 to 1.08 in 2000, should target 0.8 mSv in the year 2005 term in order to meet the results of the best nuclear operators. One of the guidelines for irradiation source term reduction is the optimization of operation parameters, including reactor coolant system (RCS) chemistry in operation, RCS shutdown chemistry and RCS cleanup improvement. This paper presents the EDF strategy for the shutdown and start up RCS chemistry optimization. All the shutdown modes have been reviewed and for each of them, the chemical specifications will be fine tuned. A survey of some US PWRs shutdown practices has been conducted for an acid and reducing shutdown chemistry implementation test at one EDF unit. This survey shows that deviating from the EPRI recommended practice for acid and reducing shutdown chemistry is possible and that critical path impact can be minimized. The paper also presents some investigations about soluble and insoluble species behavior and characterization; the study focuses here on 110m Ag, 122 Sb, 124 Sb and iodine contamination. Concerning RCS cleanup improvement, the paper presents two studies. The first one highlights some limited design modifications that are either underway or planned, for an increased flow rate during the most critical periods of the shutdown. The second one focuses on the strategy EDF envisions for filters and resins selection criteria. Matching the study on contaminants behavior with the study of filters and resins selection criteria should allow improving the cleanup efficiency. (authors)

  16. First LHC Shutdown: Coordination and Schedule Issues

    CERN Document Server

    Coupard, J; Grillot, S

    2010-01-01

    The first LHC shutdown started in fall 2008, just after the incident on the 19th of September 2008. In addition to the typical work of a shutdown, a large number of interventions, related to the “consolidation after the incident” were performed in the LHC loop. Moreover the amount of work increased during the shutdown, following the recommendations and conclusions of the different working groups in charge of the safety of the personnel and of the machine. This paper will give an overview of the work performed, the organization of the coordination, emphasizing the new safety risks (electrical and cryogenic), and how the interventions were implemented in order to ensure both the safety of personnel and a minimized time window.

  17. Training simulator for advanced gas-cooled reactor (AGR) shutdown sequence equipment

    International Nuclear Information System (INIS)

    Shankland, J.P.; Nixon, G.L.

    1978-01-01

    Successful shutdown of nuclear plant is of prime importance for both safety and economic reasons and large sums of money are spent on equipment to make shutdowns fully automatic, thus removing the possibility of operator errors. While this aim can largely be realized, one must consider the possibility of automatic equipment or plant failures when operators are required to take manual action, and off-line training facilities should be available to operating staff to minimize the risk of incorrect actions being taken. This paper presents the practice adopted at Hunterston 'B' Nuclear Power Station to solve this problem and concerns the computer-based training simulator for the Reactor Shutdown Sequence Equipment (RSSE) which was commissioned in January 1977. The plant associated with shutdown is briefly described and the reasoning which shows the need for a simulator is outlined. The paper also gives details of the comprehensive facilities available on the simulator and goes on to describe the form that shutdown training takes and the experience gained at this time. (author)

  18. The accidents during shutdown conditions Temelin NPP

    International Nuclear Information System (INIS)

    Sykora, M.; Mlady, O.

    1996-01-01

    Two parallel activities oriented for the accidents during shutdown conditions are performed at Temelin NPP: Development of symptom based emergency operating procedures (EOPs) applicable for the accidents which could occur during operational modes 1 through 4; independent evaluation of plant safety as part of the Temelin Shutdown probabilistic assessment to define the accidents which could occur during mode 5 and 6 for which the EOPs must be extended. Both these activities are in progress now because Temelin plant is still in the construction phase

  19. Permanent education

    International Nuclear Information System (INIS)

    Gardien, S.; Kirsch, R.

    1998-01-01

    The permanent education of the IPN-Lyon inscribes itself completely in the priorities of the tri-annual plan of education of CNRS. These priorities contribute to evolution of research, evaluation of the professions, integration during the professional carriers of the personnel and form the frame for new management practice implementation

  20. Measurement of the power trasient and valve closing time, for the zone control system, during a programmed shutdown in August 1989 and its relation with the class IV partial loss event occurred on 27/12/88 in CNE (Embalse nuclear power plant)

    International Nuclear Information System (INIS)

    Paz, A.O. de; Moreno, C.A.; Vinez, J.C.

    1990-01-01

    A description is made of a number of measurements performed during the programmed shutdown on Embalse nuclear power plant (CNE) (August 1989) to validate the existance of a reactivity insertion owing to the emptying of the liquid zone control system. In the event occurred on 27/12/88 when there was a partial loss Cl IV. Once the existance of this contribution was confirmed, the pertinent corrective measures were taken and the test was repeated to verify the effectiveness of the latter. The temporal evolution of a number of neutronic variables and process variables of the liquid zone system were stored in an IBM-PC XT equipped with analog-to-digital converters, for later analysis. (Author) [es

  1. Nuclear Energy Data - 2014

    International Nuclear Information System (INIS)

    2014-01-01

    Nuclear Energy Data is the OECD Nuclear Energy Agency's annual compilation of statistics and country reports documenting the status of nuclear power in the OECD area. Information provided by member country governments includes statistics on installed generating capacity, total electricity produced by all sources and by nuclear power, nuclear energy policies and fuel cycle developments, as well as projected generating capacity and electricity production to 2035, where available. Total electricity generation at nuclear power plants and the share of electricity production from nuclear power plants remained steady in 2013 despite the progressive shutdown of all reactors in Japan leading up to September and the permanent closure of six reactors in the OECD area. Governments committed to maintaining nuclear power in the energy mix advanced plans for increasing nuclear generating capacity, and progress was made in the development of deep geological repositories for spent nuclear fuel, with Finland expected to have the first such facility in operation in the early 2020's. Further details on these and other developments are provided in the publication's numerous tables, graphs and country reports. This publication contains 'StatLinks'. For each StatLink, the reader will find a URL which leads to the corresponding spreadsheet. These links work in the same way as an Internet link. (authors)

  2. On line testing of shutdown system

    International Nuclear Information System (INIS)

    Ramnath, S.; Swaminathan, P.; Sreenivasan, P.

    1997-01-01

    For ensuring high reliability and availability, safety related Instrumentation channels are triplicated. Solid state electronics can fail in safe or unsafe mode. Hence, it is necessary to supervise the safety related Instrumentation channels from sensor to final shutdown system. Microprocessor/ Microcontroller/ ASIC based online supervision systems are detailed in this paper. (author)

  3. Component failures that lead to manual shutdowns

    International Nuclear Information System (INIS)

    1979-01-01

    The data for this report are taken from a population of thirty-five LWRs, al of which differ appreciably in size, design, and age. Appendix A provides a graphical display of the number of manual shutdowns per operating year as a function of plant age, with the frequency adjusted to reflect plant availability

  4. Impact of shutdown risk on risk-based assessment of technical specifications

    International Nuclear Information System (INIS)

    Deriot, S.

    1992-10-01

    This paper describes the current work performed by the Research and Development Division of EDF concerning risk-based assessment of Operating Technical Specifications (OTS). The current risk-based assessment of OTS at EDF is presented. Then, the level 1 Probabilistic Safety Assessment of unit 3 of the Paluel nuclear power station (called PSA 1300) is described. It is fully computerized and takes into account the risk in shutdown states. A case study is presented. It shows that the fact of considering shutdown risk suggests that the current OTS should be modified

  5. BWR startup and shutdown activity transport control

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, S.E., E-mail: sgarcia@epri.com [Electric Power Research Inst. (EPRI), Palo Alto, California (United States); Giannelli, J.F.; Jarvis, A.J., E-mail: jgiannelli@finetech.com, E-mail: ajarvis@finetech.com [Finetech, Inc., Parsippany, New Jersey (United States)

    2010-07-01

    This paper summarizes BWR industry experience on good practices for controlling the transport of corrosion product activity during shutdowns, particularly refueling outages, and for startup chemistry control to minimize IGSCC (intergranular stress corrosion cracking). For shutdown, overall goals are to minimize adverse impacts of crud bursts and the time required to remove activated corrosion products from the reactor coolant during the shutdown process prior to refueling, and to assist plants in predicting and controlling radiation exposure during outages. For startup, the overall goals are to highlight conditions during early heatup and startup when sources of reactor coolant oxidants are high, when there is a greater likelihood for chemical excursions associated with refueling outage work activities, and when hydrogen injection is not available to mitigate IGSCC due to system design limitations. BWR water chemistry has changed significantly in recent years with the adoption of hydrogen water chemistry, zinc addition and noble metal chemical applications. These processes have, in some instances, resulted in significant activity increases during shutdown evolutions, which together with reduced time for cleanup because of shorter outages, has consequently increased outage radiation exposure. A review several recent outages shows that adverse effects from these conditions can be minimized, leading to the set of good practice recommendations for shutdown chemistry control. Most plants lose the majority of their hydrogen availability hours during early startup because feedwater hydrogen injection systems were not originally designed to inject hydrogen below 20% power. Hydrogen availability has improved through modifications to inject hydrogen at lower power levels, some near 5%. However, data indicate that IGSCC is accelerated during early startup, when dissolved oxygen and hydrogen peroxide levels are high and reactor coolant temperatures are in the 300 to 400 {sup o

  6. Effect of dc-power-system reliability on reactor-shutdown cooling

    International Nuclear Information System (INIS)

    Kolaczkowski, A.M.; Baranowsky, P.W.; Hickman, J.W.

    1981-01-01

    The DC power systems in a nuclear power plant provide control and motive power to valves, instrumentation, emergency diesel generators, and many other components and systems during all phases of plant operation including abnormal shutdowns and accident situations. A specific area of concern is the adequacy of the minimum design requirements for DC power systems, particularly with regard to multiple and common cause failures. This concern relates to the application of the single failure criterion for assuring a reliable DC power supply which may be required for the functionability of shutdown cooling systems. The results are presented of a reliability based study performed to assess the adequacy of DC power supply design requirements for currently operating light water reactors with particular attention to shutdown cooling requirements

  7. 40 CFR 52.271 - Malfunction, startup, and shutdown regulations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Malfunction, startup, and shutdown..., startup, and shutdown regulations. (a) The following regulations are disapproved because they would permit... malfunctions and/or fail to sufficiently limit startup and shutdown exemptions to those periods where it is...

  8. The permanent forward (Some episodes from the history of the Laboratory of Nuclear Problems, 1949-1999)

    International Nuclear Information System (INIS)

    Soroko, L.M.

    2001-01-01

    Out of about 6000 scientific investigations, performed at the Laboratory of Nuclear Problems of the JINR during the 50 years of its activity, there were chosen those ones which can be regarded as being on the world scale, on the Russian or, finally, on the JINR's scale. The author was a participant or the direct witness of the episodes described in this paper

  9. The political economics of the permanent war and the political economics of the nuclear war. Strategic approaches for Latin America

    International Nuclear Information System (INIS)

    Gomez L, I.I.

    2005-01-01

    This work treats on the hypothesis that the American imperialism uses its nuclear arsenal for reforming geographical spaces that allow him to impel its economic development in the context of the progressive exhaustion of the natural resources of the planet and of the ferocious dispute for market niches and investment destinations, and like the political and military decisions crawl to the different scenarios of economic competition. In the chapter 1 it is insinuated like has been reproduced the Warlike-industrial Complex (CBI) American from the second world postwar period until the present time in the idea of explaining like it is that it is valorized to the capital in scale enlarged starting from the denominated sector producing of destruction means and understanding that the system specifically capitalist is a system where continually the is destroyed previously taken place to manufacture a new merchandise in a luck of creative destruction. In the chapter 2, the topic of the specific contradictions of the CBI is approached that disable him to be the tip of lance of the world imperialism. The chapter 3 try on the productive linkages in the production of nuclear bombs, as well as in the production of the vectors of nuclear transportation and on the implications derived for the world security of the different industries associated to the nuclear energy (as the petroleum, the electricity, the natural gas) and to the transportation vectors of these locating which you/they are the different States where the world supremacy is disputed and that they have like one of its so many negotiation-confrontation letters its nuclear strategic arsenals. What is looked for in a thermonuclear war is the enemy's total elimination, from their offensive capacity, their defensive capacity, until their supplies, their reservations, etc., with the result that the chapters 4 and 5 of this thesis are presented to offer a better understanding that they mean the nuclear arsenals in the

  10. Document status for 1 and 2 Kozloduy NPP decommissioning activities -Phase 'Final Shutdown'

    International Nuclear Information System (INIS)

    Vangev, A.; Boyadjiev, Z.

    1997-01-01

    Decommissioning process (D and D) is the final phase of each nuclear reactor life cycle. The first nuclear reactor generation has reached his expiration life date. Decommissioning working documentation had not been taken into account at the project and construction stage. The decommissioning activities, planning and legislation has to develop along their operation. Most of developed nuclear energetic countries have gathered good experience and have create their own decommissioning strategy. This report represents in brief an overview of different country's approaches and the Kozloduy NPP decommissioning activity intention in near future and reviews the D and D working document status for 1 and 2 Kozloduy NPP Units decommissioning. Kozloduy NPP D and D task to the moment is to plan the first stage of the decommissioning process - 'The Final Shutdown' and to prepare the working documents for the phase execution. The Final Shutdown of Kozloduy NPP - 1 is the termination of operation of the Units 1 and 2 and the electricity production cessation after their useful life exhaust. In accordance with the legal legislation in Bulgaria only the normal planned termination of operation on units 1 and 2 should be prescribed. The project results concern the initial condition of the equipment and systems, their preparation and sequence for defueling, decontamination and dismantling. A plan for activities' organization for D and D and Complex Characterization of the Site under consideration will contain the following documents: 1. Time-schedule for the sequence of activities during the stages of the Final Shutdown and Safe Enclosure preparation. Technical project for organization of work related to Final Shutdown; 2. Complex Characterization Programme for a condition investigation of the Units 1 and 2 equipment and systems. 3. Technical project for design modifications and dismantling of equipment and systems which violate the radiation and nuclear safety during the Final Shutdown

  11. Nuclear power plants: 2013 atw compact statistics

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2014-03-15

    At the end of 2013, nuclear power plants were available for energy supply in 31 countries of the world. A total of 437 nuclear power plants were in operation with an aggregate gross power of approx. 393 GWe and an aggregate net power, respectively, of 372 GWe. This means that the number was unchanged compared to the previous year's number on 31 December 2012. The available gross power of nuclear power plants increased by approx. 2 GWe from 2012 to the end of 2013. In total 4 nuclear generating units were commissioned in 2013 in China (+2) and in the Republic Korea (+1). 6 nuclear generating units were decommissioned in 2013. Four units in the U.S.A. (-4) were shut down due to economical reasons. In Canada (-2) the operation status of 2 units was changed from long-term shutdown to permanently shutdown. 70 nuclear generating units with an aggregate gross power of approx. 73 GWe, were under construction in 15 countries end of 2013. New or continued projects are notified from (in brackets: number of new projects) China (+3), Belarus (+1), Rep. of Korea (+1) and the United Arab Emirates (+1). Some 115 new nuclear power plants are in the concrete project design, planning and licensing phases worldwide; on some of them, contracts have already been awarded. Another units are in their preliminary project phases. (orig.)

  12. Nuclear power plants: 2013 atw compact statistics

    International Nuclear Information System (INIS)

    Anon.

    2014-01-01

    At the end of 2013, nuclear power plants were available for energy supply in 31 countries of the world. A total of 437 nuclear power plants were in operation with an aggregate gross power of approx. 393 GWe and an aggregate net power, respectively, of 372 GWe. This means that the number was unchanged compared to the previous year's number on 31 December 2012. The available gross power of nuclear power plants increased by approx. 2 GWe from 2012 to the end of 2013. In total 4 nuclear generating units were commissioned in 2013 in China (+2) and in the Republic Korea (+1). 6 nuclear generating units were decommissioned in 2013. Four units in the U.S.A. (-4) were shut down due to economical reasons. In Canada (-2) the operation status of 2 units was changed from long-term shutdown to permanently shutdown. 70 nuclear generating units with an aggregate gross power of approx. 73 GWe, were under construction in 15 countries end of 2013. New or continued projects are notified from (in brackets: number of new projects) China (+3), Belarus (+1), Rep. of Korea (+1) and the United Arab Emirates (+1). Some 115 new nuclear power plants are in the concrete project design, planning and licensing phases worldwide; on some of them, contracts have already been awarded. Another units are in their preliminary project phases. (orig.)

  13. Verification and validation of the R2Smesh approach for the calculation of high resolution shutdown dose rate distributions

    Czech Academy of Sciences Publication Activity Database

    Majerle, Mitja; Leichtle, D.; Fischer, U.; Serikov, A.

    2012-01-01

    Roč. 87, 5-6 (2012), s. 443-447 ISSN 0920-3796 Institutional support: RVO:61389005 Keywords : MCNP * FISPACT * shutdown dose rate Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 0.842, year: 2012

  14. Controlled shutdown of a fuel cell

    Science.gov (United States)

    Clingerman, Bruce J.; Keskula, Donald H.

    2002-01-01

    A method is provided for the shutdown of a fuel cell system to relieve system overpressure while maintaining air compressor operation, and corresponding vent valving and control arrangement. The method and venting arrangement are employed in a fuel cell system, for instance a vehicle propulsion system, comprising, in fluid communication, an air compressor having an outlet for providing air to the system, a combustor operative to provide combustor exhaust to the fuel processor.

  15. MCR2S unstructured mesh capabilities for use in shutdown dose rate analysis

    International Nuclear Information System (INIS)

    Eade, T.; Stonell, D.; Turner, A.

    2015-01-01

    Highlights: • Advancements in shutdown dose rate calculations will be needed as fusion moves from experimental reactors to full scale demonstration reactors in order to ensure the safety of personnel. • The MCR2S shutdown dose rate tool has been modified to allow shutdown dose rates calculations using an unstructured mesh. • The unstructured mesh capability of MCR2S was used on three shutdown dose rate models, a simple sphere, the ITER computational benchmark and the DEMO computational benchmark. • The results showed a reasonable agreement between an unstructured mesh approach and the CSG approach and highlighted the need to carefully choose the unstructured mesh resolution. - Abstract: As nuclear fusion progresses towards a sustainable energy source and the power of tokamak devices increases, a greater understanding of the radiation fields will be required. As well as on-load radiation fields, off-load or shutdown radiation field are an important consideration for the safety and economic viability of a commercial fusion reactor. Previously codes such as MCR2S have been written in order to predict the shutdown dose rates within, and in regions surrounding, a fusion reactor. MCR2S utilises a constructive solid geometry (CSG) model and a superimposed structured mesh to calculate 3-D maps of the shutdown dose rate. A new approach to MCR2S calculations is proposed and implemented using a single unstructured mesh to replace both the CSG model and the superimposed structured mesh. This new MCR2S approach has been demonstrated on three models of increasing complexity. These models were: a sphere, the ITER computational shutdown dose rate benchmark and the DEMO computational shutdown dose rate benchmark. In each case the results were compared to MCR2S calculations performed using MCR2S with CSG geometry and a superimposed structured mesh. It was concluded that the results from the unstructured mesh implementation of MCR2S compared well to the CSG structured mesh

  16. Evolution of shutdown mechanism for PHWRs

    International Nuclear Information System (INIS)

    Singh, Manjit; Govindarajan, G.

    1997-01-01

    In 500 MWe PHWR, there are two independent fast acting shutdown systems namely (1) mechanical shut-off rod system and (2) liquid poison injection system. Both systems are independently capable of keeping the reactor in sub-critical condition during long shutdown. Mechanical shut-off rod system being primary shutdown system calls for a very high reliability of operation as well as effectiveness, which are mainly governed by its ability to operate within a very short time and the magnitude of negative reactivity worth it can provide. Mechanical shut-off rods are normally parked above the core by shut-off rod drive mechanism. On receiving a scram signal, shut-off rods are released from the holding electromagnetic clutch and fall under gravity into the core. This paper discusses the salient features of mechanical shut-off rod system. A brief account of detailed design and development of sub-assemblies of shut-off rod drive mechanism is also presented. (author)

  17. Shutdown chemistry optimization at Maanshan NPP

    International Nuclear Information System (INIS)

    Sun Yuanlung; Chuang Benjamin; Su Kouhwa; Kao Jueiting

    2009-01-01

    At Maanshan PWRs, a significant piping radiation buildup caused by crud burst from fuel surface in the beginning of RFO used to be blamed as a contribution to high personal exposures during outage. Therefore, several modifications on shutdown chemistry procedures such as, early lithium removal, rapid boration, dissolved hydrogen removal, extended RCP operation, and maintaining maximum let down flow, have been consecutively conducted since no.1RFO-16, 2006. The important operational and chemical parameters of modified shutdown chemistry procedures adopted in no.2 RFO-17, 2008 and superiority in low reading (2 mSv/hr) from let down heat exchangers area radiation monitor over 11mSv/hr of no.1 RFO-16 at the same area will be addressed in this paper. At the end of no.2 RFO-17, low personal exposures of 765 man-mSv (TLD)verified the absence of crud burst during shutdown chemistry process and broke records of Maanshan NPP as well. Even with a new job on PZR pre-emptive dissimilar weld overlay which exhausting 17.37% of total 797 man-mSv(TLD) in the latest no.1 RFO-18, 659 man-mSv (TLD) made another record low in the history of Maanshan. (author)

  18. LMFBR self-activated shutdown systems

    International Nuclear Information System (INIS)

    Sowa, E.S.; Barthold, W.P.; Eggen, D.T.; Huebotter, P.R.; Josephson, J.; Pizzica, P.A.; Turski, R.B.; van Erp, J.B.

    1976-01-01

    Self-actuated shutdown systems (SASSs), fully contained within the dimensions of a fuel subassembly and installed in the core in judiciously chosen locations, can provide an important additional safety feature for LMFBRs. If actuated by phenomena inherent to the system and its immediate environment, these systems can contribute considerably to the total reliability of the overall plant protection system, in particular as regards protection against human error. It was shown that this type of shutdown system is capable of inserting a substantial amount of negative reactivity into the core with a relatively small impact on plant performance. Furthermore, it was shown that a coolable geometry can be maintained in LMFBRs of current design for a wide spectrum of accident initiators, and for a range of response times and insertion rates which appear to be achievable within practical design limits. Experiments showed that Curie-point-operated devices have considerable promise for application in self-actuated shutdown systems, in particular as regards meeting the requirements of testability and resettability

  19. Communication of 8 June 2009 received from the Permanent Mission of the Republic of Korea concerning a non-paper 'The Republic of Korea's suggestion on possible criteria for multilateral approaches to the nuclear fuel cycle'

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a communication dated 8 June 2009 from the Permanent Mission of the Republic of Korea, transmitting the text of a non-paper entitled 'The Republic of Korea's Suggestion on Possible Criteria for Multilateral Approaches to the Nuclear Fuel Cycle'. As requested in that communication, the abovementioned non-paper is herewith circulated for the information of all Member States

  20. Communication from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for transfers of nuclear-related dual-use equipment, materials, software and related technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-08-04

    The document reproduces the text of the Note Verbale received by the Director General of the IAEA from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency providing information on the export policies and practices of the Government of the Russian Federation with respect to the export of nuclear-related dual-use equipment, materials, software and related technology.

  1. Communication from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for transfers of nuclear-related dual-use equipment, materials, software and related technology

    International Nuclear Information System (INIS)

    2000-01-01

    The document reproduces the text of the Note Verbale received by the Director General of the IAEA from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency providing information on the export policies and practices of the Government of the Russian Federation with respect to the export of nuclear-related dual-use equipment, materials, software and related technology

  2. Communication from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency regarding the export of nuclear material and of certain categories of equipment and other material

    International Nuclear Information System (INIS)

    2000-01-01

    The document reproduces the text of a letter received by the Director general of the IAEA from Permanent Mission of the Russian Federation to the International Atomic Energy Agency concerning the export of nuclear material and of certain categories of equipment and other material

  3. Communication from the Permanent Mission of Malta to the International Atomic Energy Agency regarding guidelines for the transfers of nuclear-related dual-use equipment, materials, software and related technology

    International Nuclear Information System (INIS)

    2004-01-01

    The Director General has received a Note Verbale from the Permanent Mission of Malta, dated 3 December 2003, regarding Malta's nuclear policies and practices. In the light of the wish expressed at the end of the Note Verbale, its text is attached

  4. Communication of 29 April 1996 received from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-07

    The document contains the text of a note verbale dated 29 April 1996 received by the Director General of IAEA from the Permanent Mission of the Russian Federation which provides information on the export policies and practices of the Government of the Russian Federation with respect to transfer of nuclear-related dual-use equipment, material and related technology.

  5. Communication of 29 April 1996 received from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    1996-01-01

    The document contains the text of a note verbale dated 29 April 1996 received by the Director General of IAEA from the Permanent Mission of the Russian Federation which provides information on the export policies and practices of the Government of the Russian Federation with respect to transfer of nuclear-related dual-use equipment, material and related technology

  6. Communication dated 4 July 2008 received from the Permanent Mission of Mongolia to the Agency concerning implementation of the law of Mongolia on its nuclear-weapon-free status

    International Nuclear Information System (INIS)

    2008-01-01

    The Secretariat has received a Note Verbale dated 4 July 2008 from the Permanent Mission of Mongolia requesting that information pertaining to the law of Mongolia on its nuclear-weapon-free status be circulated as an information document. The Note Verbale and, as requested therein, the attachment thereto, are circulated herewith for the information of Member States

  7. The use of digital computers in CANDU shutdown systems

    International Nuclear Information System (INIS)

    Gilbert, R.S.; Komorowski, C.W.

    1986-01-01

    This paper summarizes the application of computers in CANDU shutdown systems. A general description of systems that are already in service is presented along with a description of a fully computerized shutdown system which is scheduled to enter service in 1987. In reviewing the use of computers in the shutdown systems there are three functional areas where computers have been or are being applied. These are (i) shutdown system monitoring, (ii) parameter display and testing and (iii) shutdown initiation. In recent years various factors (References 1 and 2) have influenced the development and deployment of systems which have addressed two of these functions. At the present time a system is also being designed which addresses all of these areas in a comprehensive manner. This fully computerized shutdown system reflects the previous design, and licensing experience which was gained in earlier applications. Prior to describing the specific systems which have been designed a short summary of CANDU shutdown system characteristics is presented

  8. Nuclear decommissioning planning, execution and international experience

    CERN Document Server

    2012-01-01

    A title that critically reviews the decommissioning and decontamination processes and technologies available for rehabilitating sites used for nuclear power generation and civilian nuclear facilities, from fundamental issues and best practices, to procedures and technology, and onto decommissioning and decontamination case studies.$bOnce a nuclear installation has reached the end of its safe and economical operational lifetime, the need for its decommissioning arises. Different strategies can be employed for nuclear decommissioning, based on the evaluation of particular hazards and their attendant risks, as well as on the analysis of costs of clean-up and waste management. This allows for decommissioning either soon after permanent shutdown, or perhaps a long time later, the latter course allowing for radioactivity levels to drop in any activated or contaminated components. It is crucial for clear processes and best practices to be applied in decommissioning such installations and sites, particular where any ...

  9. RECAP, Replacement Energy Cost for Short-Term Reactor Plant Shut-Down

    International Nuclear Information System (INIS)

    VanKuiken, J.C.; Daun, C.J.; Jusko, M.J.

    1995-01-01

    1 - Description of program or function: RECAP (Replacement Energy Cost Analysis Package) determines the replacement energy costs associated with short-term shutdowns or de-ratings of one or more nuclear reactors. Replacement energy cost refers to the change in generating-system production cost that results from shutting down a reactor. The cost calculations are based on the seasonal, unit-specific cost estimates for 1988-1991 for all 117 nuclear electricity-generating units in the U.S. RECAP is menu-driven, allowing the user to define specific case studies in terms of parameters such as the units to be included, the length and timing of the shutdown or de-rating period, the unit capacity factors, and the reference year for reporting cost results. In addition to simultaneous shutdown cases, more complicated situations, such as overlapping shutdown periods or shutdowns that occur in different years, can be examined through use of a present-worth calculation option. 2 - Method of solution: The user selects a set of units for analysis, defines a shutdown (or de-rating) period, and specifies any planned maintenance outages, delays in unit start-ups, or changes in default capacity factors. The program then determines which seasonal cost numbers to apply, estimates total and daily costs, and makes the appropriate adjustments for multiple outages if they are encountered. The change in production cost is determined from the difference between the total variable costs (variable fuel cost, variable operation and maintenance cost, and purchased energy cost) when the reactor is available for generation and when it is not. Changes in reference-year dollars are based on gross national product (GNP) price deflators or on optional use inputs. Once RECAP has completed the initial cost estimates for a case study (or series of case studies), present-worth analysis can be conducted using different reference-year dollars and discount rates, as specified by the user. The program uses

  10. Brief account of the design philosophy for third Qinshan NPP shutdown safety system based on practical application

    International Nuclear Information System (INIS)

    Xiong Weihua

    2005-01-01

    Qinshan CANDU power plant is uses the Canadian proven CANDU6 nuclear power technology. It has two characteristic: 1. heavy water-as moderator and coolant; 2. natural uranium as the fuel and change fuel during normal operating. CANDU6 include four special safety system: the No.1 shutdown system (SDS No.1), the No.2 shutdown system (SDS No.2), the containment system, the emergency core cooling system (ECCS). QinShan CANDU power plant is the first commercial PHWR nuclear power plant in China. And some aspect is not similar to everybody. The intention of the article is to introduce the basic design and functions. (authors)

  11. Nuclear power world report 2013

    International Nuclear Information System (INIS)

    Anon.

    2014-01-01

    At the end of 2013, 435 nuclear power plants were available for energy supply in 31 countries of the world. This means that the number decreased by 2 units compared to the previous year's number on 31 December 2012. The aggregate gross power of the plants amounted to approx. 398,861 MWe, the aggregate net power, to 378,070 MWe (gross: 392,793 MWe, net: 372,572 MWe, new data base as of 2013: nameplate capacities). Four units were commissioned in 2014; three units in China and one in India. Eight units were shut down permanently in 2013; 2 units in Japan, and four units in the USA. Two units in Canada were declared permanently shut-down after a long-term shutdown. 70 nuclear generating units - 2 more than at the end of 2012 - were under construction in late 2013 in 15 countries with an aggregate gross power of approx. 73,814 MWe and net power of approx. 69,279 MWe. Six new projects have been started in 2013 in four countries (Belarus, China, the Republic of Korea, and the United Arab Emirates). Worldwide, some 125 new nuclear power plants are in the concrete project design, planning, and licensing phases; in some of these cases license applications have been submitted or contracts have already been signed. Some 100 further projects are planned. Net electricity generation in nuclear power plants worldwide in 2013 achieved a level of approx. 2,364.15 billion (109) kWh (2012: approx. 2,350.80 billion kWh). Since the first generation of electricity in a nuclear power plant in the EBR-I fast breeder (USA) on December 20, 1951, cumulated net production has reached approx. 70,310 billion kWh, and operating experience has grown to some 15,400 reactor years. (orig.)

  12. Nuclear power world report 2013

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2014-07-15

    At the end of 2013, 435 nuclear power plants were available for energy supply in 31 countries of the world. This means that the number decreased by 2 units compared to the previous year's number on 31 December 2012. The aggregate gross power of the plants amounted to approx. 398,861 MWe, the aggregate net power, to 378,070 MWe (gross: 392,793 MWe, net: 372,572 MWe, new data base as of 2013: nameplate capacities). Four units were commissioned in 2014; three units in China and one in India. Eight units were shut down permanently in 2013; 2 units in Japan, and four units in the USA. Two units in Canada were declared permanently shut-down after a long-term shutdown. 70 nuclear generating units - 2 more than at the end of 2012 - were under construction in late 2013 in 15 countries with an aggregate gross power of approx. 73,814 MWe and net power of approx. 69,279 MWe. Six new projects have been started in 2013 in four countries (Belarus, China, the Republic of Korea, and the United Arab Emirates). Worldwide, some 125 new nuclear power plants are in the concrete project design, planning, and licensing phases; in some of these cases license applications have been submitted or contracts have already been signed. Some 100 further projects are planned. Net electricity generation in nuclear power plants worldwide in 2013 achieved a level of approx. 2,364.15 billion (109) kWh (2012: approx. 2,350.80 billion kWh). Since the first generation of electricity in a nuclear power plant in the EBR-I fast breeder (USA) on December 20, 1951, cumulated net production has reached approx. 70,310 billion kWh, and operating experience has grown to some 15,400 reactor years. (orig.)

  13. A Fast Shutdown Technique for Large Tokamaks

    International Nuclear Information System (INIS)

    Fredrickson, E.; Schmidt, G.L.; Hill, K.; Jardin, S.C.

    1999-01-01

    A practical method is proposed for the fast shutdown of a large ignited tokamak. The method consists of injecting a rapid series of 30-50 deuterium pellets doped with a small ( 0.0005%) concentration of Krypton impurity, and simultaneously ramping the plasma current and shaping fields down over a period of several seconds using the poloidal field system. Detailed modeling with the Tokamak Simulation Code using a newly developed pellet mass deposition model shows that this method should terminate the discharge in a controlled and stable way without producing significant numbers of runaway electrons. A partial prototyping of this technique was accomplished in TFTR

  14. Technical Assessment: WRAP 1 HVAC Passive Shutdown

    International Nuclear Information System (INIS)

    Ball, D.E.; Nash, C.R.; Stroup, J.L.

    1993-01-01

    As the result of careful interpretation of DOE Order 6430.lA and other DOE Orders, the HVAC system for WRAP 1 has been greatly simplified. The HVAC system is now designed to safely shut down to Passive State if power fails for any reason. The fans cease functioning, allowing the Zone 1 and Zone 2 HVAC Confinement Systems to breathe with respect to atmospheric pressure changes. Simplifying the HVAC system avoided overdesign. Construction costs were reduced by eliminating unnecessary equipment. This report summarizes work that was done to define the criteria, physical concepts, and operational experiences that lead to the passive shutdown design for WRAP 1 confinement HVAC systems

  15. Radiochemical guidelines and process specifications for reactor shutdown: the EDF strategy

    International Nuclear Information System (INIS)

    Mole, D.; Wintergerst, M.; Meylogan, Th.; Rocher, A.; Sagot, M.J.; Bonelli, V.; Bonnefon, J.; Dupont, B.

    2012-09-01

    Changes to French nuclear regulations made in June 2006 [1.] have made it necessary for EDF to modify its ruling principles. These modifications required the restructuring of radiochemical guidelines to better reflect their impact on nuclear safety, the environment and radioprotection. In accordance with these aims, a new authoritative document has been produced. This ruling document identifies all parameters with a potential impact on nuclear safety, radiological releases to the environment and personnel dose rates. These diagnostic and control parameters have been identified for a reactor in production and for a reactor during shutdown. For parameters related to a reactor in production, some indicators are used to evaluate impacts on availability, radioprotection and the environment during shutdown and on outage and to anticipate mitigation ways. On the other side, several parameters related to the stages of shutdown were also directly evaluated in order to minimize the impacts. This paper describes the EDF methodology used to establish operational documents: radiochemical guidelines and process specifications, and includes the following: - description of monitored parameters and their associated areas of risk; - justification of target values, frequencies of inspection and the required actions for the monitored parameters. The sizing methodology is based on theoretical studies and on EDF operational experience analysis. By implementing in the operational and technical specifications requirements linked to nuclear safety, radioprotection and environment respect, EDF will benefit from an improved compromise between these areas as well as an increased focus. (authors)

  16. TRACG-CFD analysis of ESBWR reactor water cleanup shutdown cooling system mixing coefficient

    International Nuclear Information System (INIS)

    Gallardo, J.; Marquino, W.; Mistreanu, A.; Yang, J.

    2015-09-01

    The ESBWR is a 1520 nominal [M We] Generation III+ natural circulation boiling water reactor designed to high levels of safety utilizing features that have been successfully used before in operating BWRs, as well as standard features common to A BWR. In September of 2014, the US NRC has certified the ESBWR design for use in the USA. The RWCU/Sdc is an auxiliary system for the ESBWR nuclear island. Basic functions it performs include purifying the reactor coolant during normal operation and shutdown and providing shutdown cooling and cooldown to cold shutdown conditions. The performance of the RWCU system during shutdown cooling is directly related to the temperature of the water removed through the outlets, which is coupled with the vessel and F W temperatures through a thermal mixing coefficient. The complex three-dimensional (3-D) geometry of the BWR downcomer and lower plenum has a great impact on the flow mixing. Only a fine mesh technique like CFD can predict the 3-D temperature distribution in the RPV during shutdown and provide the RWCU/Sdc system inlet temperature. Plant shutdown is an unsteady event by nature and was modeled as a succession of CFD steady-state simulations. It is required to establish the mixing coefficient (which is a function of the heat balance and the core flow) during the operation of the RWCU system in the multiple shutdown cooling modes, and therefore a range of core flows needs to be estimated using quasi steady states obtained with TRACG. The lower end of that range is obtained from a system with minimal power decay heat and core flow; while the higher end corresponds to the power at the beginning of RWCU/Sdc operation when the cooldown is transferred to the RWCU/Sdc after the initial depressurization via the turbine bypass valves. Because the ESBWR RWCU/Sdc return and suction designs provide good mixing, the uniform mixing energy balance was found to be an adequate alternative for deriving the mixing coefficient. The CFD mass flow

  17. TRACG-CFD analysis of ESBWR reactor water cleanup shutdown cooling system mixing coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, J. [UNAM, Facultad de Ingenieria, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Marquino, W.; Mistreanu, A.; Yang, J., E-mail: euqrop@hotmail.com [General Electric Hitachi Nuclear Energy, Wilmington, 28401 North Carolina (United States)

    2015-09-15

    The ESBWR is a 1520 nominal [M We] Generation III+ natural circulation boiling water reactor designed to high levels of safety utilizing features that have been successfully used before in operating BWRs, as well as standard features common to A BWR. In September of 2014, the US NRC has certified the ESBWR design for use in the USA. The RWCU/Sdc is an auxiliary system for the ESBWR nuclear island. Basic functions it performs include purifying the reactor coolant during normal operation and shutdown and providing shutdown cooling and cooldown to cold shutdown conditions. The performance of the RWCU system during shutdown cooling is directly related to the temperature of the water removed through the outlets, which is coupled with the vessel and F W temperatures through a thermal mixing coefficient. The complex three-dimensional (3-D) geometry of the BWR downcomer and lower plenum has a great impact on the flow mixing. Only a fine mesh technique like CFD can predict the 3-D temperature distribution in the RPV during shutdown and provide the RWCU/Sdc system inlet temperature. Plant shutdown is an unsteady event by nature and was modeled as a succession of CFD steady-state simulations. It is required to establish the mixing coefficient (which is a function of the heat balance and the core flow) during the operation of the RWCU system in the multiple shutdown cooling modes, and therefore a range of core flows needs to be estimated using quasi steady states obtained with TRACG. The lower end of that range is obtained from a system with minimal power decay heat and core flow; while the higher end corresponds to the power at the beginning of RWCU/Sdc operation when the cooldown is transferred to the RWCU/Sdc after the initial depressurization via the turbine bypass valves. Because the ESBWR RWCU/Sdc return and suction designs provide good mixing, the uniform mixing energy balance was found to be an adequate alternative for deriving the mixing coefficient. The CFD mass flow

  18. Shutdown risk management applied at Philadelphia Electric Company

    International Nuclear Information System (INIS)

    Dagan, William J.; True, Douglas E.; Wilson, Thomas; Truax, William

    2004-01-01

    The development and implementation of an effective risk management program requires basic risk or safety knowledge and the conversion of such information into effective management tools. ERIN Engineering and Research, Inc., under contract to the Electric Power Research Institute, has developed an effective program. Outage Risk Assessment and Management (ORAM), to provide plant and management personnel with understandable results of shutdown risk studies. With this tool, the impact of plans and decision options can be readily determined and displayed for the decision maker. This paper describes these methods and their application to the Limerick Nuclear Station of Philadelphia Electric Company. It also sets forth a broader application of these methods to include support of management decisions at-power and following forced outages. The result is an integrated risk management framework which can allow management and technical personnel to utilize readily available and understandable risk insights to optimize each activity. This paper addresses the resolution of several key issues in detail: How was the ORAM risk management method employed to represent the existing plant shutdown procedures and policies? How did the ORAM risk management method enhance the decision-making ability of the outage management staff? How was the ORAM software efficiently integrated with the outage scheduling software? How is quantitative risk information generated and used for outage planning and control? The ORAM risk management philosophy utilizes a series of colors to depict various risk configurations. Each such configuration has associated with it clear guidance. By modifying the conditions existing in the plant it is possible to impact the type of risk being encountered as well as the guidance which is appropriate for that period. In addition, the duration of a particular configuration can be effectively managed to reduce the overall risk impact. These are achieved with minimal

  19. IAEA’s Perspectives on Global Nuclear Power – Opportunities and Challenges

    International Nuclear Information System (INIS)

    Park, J.K.

    2014-01-01

    Status of global nuclear power: 437 reactors in operation (374.5 GWe); 2 reactors in long-term shutdown; 149 reactors in permanent shutdown; 70 reactors under construction. [As of Sep. 2014] Latest connections to the grid: - Ningde-2, 1000 MW(e), PWR, China; - Atucha-2, 692 MW(e), PHWR, Argentina; - Fuqing-1, 1000 MW(e), PWR, China). [Website: http://www.iaea.org/pris/]. IAEA projections of nuclear power: • Sep. 2014: 374.5 GWe; • 2030 - low 400.6 GWe: 7.0% increase; - high 699.2 GWe: 86.7% increase; • 2050 - low 412.9 GWe: 10.3% increase; - high 1091.7 GWe: 191.5% increase

  20. The Intelligent Safety System: could it introduce complex computing into CANDU shutdown systems

    International Nuclear Information System (INIS)

    Hall, J.A.; Hinds, H.W.; Pensom, C.F.; Barker, C.J.; Jobse, A.H.

    1984-07-01

    The Intelligent Safety System is a computerized shutdown system being developed at the Chalk River Nuclear Laboratories (CRNL) for future CANDU nuclear reactors. It differs from current CANDU shutdown systems in both the algorithm used and the size and complexity of computers required to implement the concept. This paper provides an overview of the project, with emphasis on the computing aspects. Early in the project several needs leading to an introduction of computing complexity were identified, and a computing system that met these needs was conceived. The current work at CRNL centers on building a laboratory demonstration of the Intelligent Safety System, and evaluating the reliability and testability of the concept. Some fundamental problems must still be addressed for the Intelligent Safety System to be acceptable to a CANDU owner and to the regulatory authorities. These are also discussed along with a description of how the Intelligent Safety System might solve these problems

  1. Study on the Post-Fire Safe-Shutdown Analysis for CANDU NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Hwan; Kim, Yun Jung; Park, Mun Hee [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The purpose of this paper is to study a method of the Post-Fire Safe-Shutdown Analysis in order to apply to CANDU NPPs when one group of the Safety Structures, Systems and Components(SCCs) is failed by Fire. The purpose of Fire Protection is prevention, suppression of the fire and mitigation of the effect on the Nuclear Safety. When fire takes place at the Nuclear Power Plants(NPPs), the reactor should achieve and maintain safe shut-down condition and minimize radioactive material release to an environment. The purpose of the Post-Fire SSA process is an evaluation process during a fire at NPPs. At this study, the process was conceptually adopted for control room complex of CANDU NPPs. The Core Damage Frequency of the Reactor will be evaluated more accurately if the SSA is adopted adequately at a fire.

  2. LHC Report: The shutdown work nearing completion

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The work planned for the LHC injector chain during the winter shutdown is nearing completion. The PS Booster (PSB) and PS will be closed to access next week, and the control of machine access will be transferred to the CERN Control Centre in preparation for the resumption of machine operation. Hardware tests are being performed in all the machines.   Tests are under way in the LHC tunnel. The technical teams are putting the finishing touches to the work planned for the winter shutdown. At the Linac2, the PS Booster and the PS, work will be completed next week and hardware tests will be carried out soon after. POPS, the new powering system for the PS, will be commissioned for the first time in the coming days after the necessary preliminary tests have been carried out. At the SPS, various magnets have been replaced over recent weeks and the performance tests on the main power supply and other hardware tests will be able to start shortly. After that, the machine will be ready for operation with b...

  3. Technical Meeting on Passive Shutdown Systems for Liquid Metal-Cooled Fast Reactors. Working Material

    International Nuclear Information System (INIS)

    2015-01-01

    A major focus of the design of modern fast reactor systems is on inherent and passive safety. Specific systems to improve reactor safety performance during accidental transients have been developed in nearly all fast reactor programs, and a large number of proposed systems have reached various stages of maturity. This Technical Meeting on Passive Shutdown Systems for Fast Reactors, which was recommended by the Technical Working Group on Fast Reactors (TWG-FR), addressed Member States’ expressed need for information exchange on projects and programs in the field, as well as for the identification of priorities based on the analysis of technology gaps to be covered through R&D activities. This meeting was limited to shutdown systems only, and did not include other passive features such as natural circulation decay heat removal systems etc.; however the meeting catered to passive shutdown safety devices applicable to all types of fast neutron systems. It was agreed to initiate a new study and produce a Nuclear Energy Series (NES) Technical Report to collect information about the existing operational systems as well as innovative concepts under development. This will be a useful source for member states interested in gaining technical expertise to develop passive shutdown systems as well as to highlight the importance and development in this area

  4. Nuclear energy over the last 20 years and current developments

    International Nuclear Information System (INIS)

    1995-01-01

    The round-table debate was chaired by Jose Maria Fernandez-Rua, who began with a presentation of the current situation in the nuclear sector, namely the permanent shutdown of Lemoniz, Valdecaballeros and Trillo nuclear power plants, and continued with the introduction of the participants: Javier de Pinedo, Director of Generation for Iberdrola; Alberto Lopez, General Manager of Enresa; Guillermo Velarde, Director of the Institute of Nuclear Fusion of the ETSIIM; Adolfo Garcia Rodriguez, General Manager of Empresarios Agrupados; Enrique Garcia Alvarez, technical Director of the Endesa Group; Rafael Caro, Member of the Nuclear Safety Council; Juan Velarde Fuentes; Professor of Economics at the Universidad Complutense in Madrid, and Agustin Alonso, Professor of Nuclear Technology at ETSIIM (Author)

  5. Outcomes of an international initiative for harmonization of low power and shutdown probabilistic safety assessment

    Directory of Open Access Journals (Sweden)

    Manna Giustino

    2010-01-01

    Full Text Available Many probabilistic safety assessment studies completed to the date have demonstrated that the risk dealing with low power and shutdown operation of nuclear power plants is often comparable with the risk of at-power operation, and the main contributors to the low power and shutdown risk often deal with human factors. Since the beginning of the nuclear power generation, human performance has been a very important factor in all phases of the plant lifecycle: design, commissioning, operation, maintenance, surveillance, modification, decommissioning and dismantling. The importance of this aspect has been confirmed by recent operating experience. This paper provides the insights and conclusions of a workshop organized in 2007 by the IAEA and the Joint Research Centre of the European Commission, on Harmonization of low power and shutdown probabilistic safety assessment for WWER nuclear power plants. The major objective of the workshop was to provide a comparison of the approaches and the results of human reliability analyses and gain insights in the enhanced handling of human factors.

  6. Needs for R and D and innovations to address challenges of nuclear facility decommissioning after its normal shutdown versus advanced approaches required for Fukushima Daiichi NPS decommissioning. Needs and emergency technologies for decommissioning

    International Nuclear Information System (INIS)

    Laurent, G.

    2017-01-01

    Taking into account several attempts to address variety of needs for R and D related to the decommissioning challenges such as: - Characterisation and survey prior to dismantling, - Technologies for dismantling, - Decontamination and on-site remediation, - Material and waste management, - Site characterisation and environmental monitoring. This presentation will give an update of approaches in several countries for R and D to aim at more efficient and effective decommissioning and, above all, to reduce current labour intensive needs to implement this kind of work. The evidence of the particular needs to coordinate efforts both for 'normal decommissioning' and accident cases like Fukushima Daiichi will be offered by demonstrating that, for a large part, that needs might be considered as similar. Some examples of particular interest will be given and it will be emphasized the need to adapt existing and/or new technologies from 'non-nuclear' areas to use them for nuclear decommissioning. The global interest to evaluate and to coordinate R and D efforts will be demonstrated. Consequently there might be a large international interest to increase the consensus where R and D can be better directed. The more comprehensive coordination should support improvement of the overview of future decommissioning needs to implement the decommissioning activities more effectively in terms of time and finance, not compromising safety. (author)

  7. Essure Permanent Birth Control

    Science.gov (United States)

    ... Prosthetics Essure Permanent Birth Control Essure Permanent Birth Control Share Tweet Linkedin Pin it More sharing options ... Print Essure is a a permanently implanted birth control device for women (female sterilization). Implantation of Essure ...

  8. COMPUTING SERVICES DURING THE ANNUAL CERN SHUTDOWN

    CERN Multimedia

    2000-01-01

    As in previous years, computing services run by IT division will be left running unattended during the annual shutdown. The following points should be noted. No interruptions are scheduled for local and wide area networking and the ACB, e-mail and unix interactive services. Maintenance work is scheduled for the NICE home directory servers and the central Web servers. Users must, therefore, expect service interruptions. Unix batch services will be available but without access to HPSS or to manually mounted tapes. Dedicated Engineering services, general purpose database services and the Helpdesk will be closed during this period. An operator service will be maintained and can be reached at extension 75011 or by email to: computer.operations@cern.ch Users should be aware that, except where there are special arrangements, any major problems that develop during this period will most likely be resolved only after CERN has reopened. In particular, we cannot guarantee backups for Home Directory files for eithe...

  9. The Shutdown Dissociation Scale (Shut-D)

    Science.gov (United States)

    Schalinski, Inga; Schauer, Maggie; Elbert, Thomas

    2015-01-01

    The evolutionary model of the defense cascade by Schauer and Elbert (2010) provides a theoretical frame for a short interview to assess problems underlying and leading to the dissociative subtype of posttraumatic stress disorder. Based on known characteristics of the defense stages “fright,” “flag,” and “faint,” we designed a structured interview to assess the vulnerability for the respective types of dissociation. Most of the scales that assess dissociative phenomena are designed as self-report questionnaires. Their items are usually selected based on more heuristic considerations rather than a theoretical model and thus include anything from minor dissociative experiences to major pathological dissociation. The shutdown dissociation scale (Shut-D) was applied in several studies in patients with a history of multiple traumatic events and different disorders that have been shown previously to be prone to symptoms of dissociation. The goal of the present investigation was to obtain psychometric characteristics of the Shut-D (including factor structure, internal consistency, retest reliability, predictive, convergent and criterion-related concurrent validity). A total population of 225 patients and 68 healthy controls were accessed. Shut-D appears to have sufficient internal reliability, excellent retest reliability, high convergent validity, and satisfactory predictive validity, while the summed score of the scale reliably separates patients with exposure to trauma (in different diagnostic groups) from healthy controls. The Shut-D is a brief structured interview for assessing the vulnerability to dissociate as a consequence of exposure to traumatic stressors. The scale demonstrates high-quality psychometric properties and may be useful for researchers and clinicians in assessing shutdown dissociation as well as in predicting the risk of dissociative responding. PMID:25976478

  10. The Shutdown Dissociation Scale (Shut-D

    Directory of Open Access Journals (Sweden)

    Inga Schalinski

    2015-05-01

    Full Text Available The evolutionary model of the defense cascade by Schauer and Elbert (2010 provides a theoretical frame for a short interview to assess problems underlying and leading to the dissociative subtype of posttraumatic stress disorder. Based on known characteristics of the defense stages “fright,” “flag,” and “faint,” we designed a structured interview to assess the vulnerability for the respective types of dissociation. Most of the scales that assess dissociative phenomena are designed as self-report questionnaires. Their items are usually selected based on more heuristic considerations rather than a theoretical model and thus include anything from minor dissociative experiences to major pathological dissociation. The shutdown dissociation scale (Shut-D was applied in several studies in patients with a history of multiple traumatic events and different disorders that have been shown previously to be prone to symptoms of dissociation. The goal of the present investigation was to obtain psychometric characteristics of the Shut-D (including factor structure, internal consistency, retest reliability, predictive, convergent and criterion-related concurrent validity.A total population of 225 patients and 68 healthy controls were accessed. Shut-D appears to have sufficient internal reliability, excellent retest reliability, high convergent validity, and satisfactory predictive validity, while the summed score of the scale reliably separates patients with exposure to trauma (in different diagnostic groups from healthy controls.The Shut-D is a brief structured interview for assessing the vulnerability to dissociate as a consequence of exposure to traumatic stressors. The scale demonstrates high-quality psychometric properties and may be useful for researchers and clinicians in assessing shutdown dissociation as well as in predicting the risk of dissociative responding.

  11. Communication dated 30 May 2007 from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland to the IAEA concerning enrichment bonds - A voluntary scheme for reliable access to nuclear fuel

    International Nuclear Information System (INIS)

    2007-01-01

    The Secretariat has received a letter dated 30 May 2007 from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland to the IAEA attaching a UK Non-paper entitled 'Food for Thought: Enrichment Bonds - A Voluntary Scheme for Reliable Access to Nuclear Fuel'. As requested in that letter, the letter and the attachment is now being circulated for the information of all Member States

  12. Communication dated 12 March 2009 received from the Permanent Missions of China, France, Germany, Russia, the United Kingdom and the United States of America regarding a joint statement on Iran's nuclear programme

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a communication dated 12 March 2009 from the Permanent Missions of China, France, Germany, Russia, the United Kingdom and the United States of America, transmitting to the attention of all Member States of the IAEA a joint statement on Iran's nuclear programme, delivered at the March Board of Governors meeting. As requested in that communication, the attached statement is herewith circulated for the information of all Member States

  13. Communication of 10 June 2009 received from the Permanent Mission of the United Kingdom with regard to the International Nuclear Fuel Supply Conference: Securing safe access to peaceful power

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a communication dated 10 June 2009 from the Permanent Mission of the United Kingdom of Great Britain and Northern Ireland, attaching a note from the United Kingdom and the final remarks of the Chairman of the International Nuclear Fuel Supply Conference: Securing safe access to peaceful power, held in London on 17 and 18 March 2009. As requested in that communication, the note and final remarks are herewith circulated for the information of Member States

  14. Communication of 29 April 1996 received from the permanent mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-07

    The Director General of the International Atomic Energy Agency has received a note verbale of 29 April 1996 from the Permanent Mission of the Russian Federation providing information on the export policies and practices of the Government of the Russian Federation with respect to nuclear transfers. In light of the request expressed in the note verbale, the text of the note verbale and its attachment is being circulated.

  15. Communication dated 29 June 2009 received from the Permanent Mission of Kazakhstan with regard to a press release to note a commemorative meeting of the 20th anniversary of shutting down of the Semipalatinsk nuclear testing site

    International Nuclear Information System (INIS)

    2009-01-01

    The Secretariat has received a Note Verbale dated 29 June 2009 from the Permanent Mission of Kazakhstan, transmitting the text of a press release to note a commemorative meeting of the 20th anniversary of shutting down of the Semipalatinsk nuclear testing site, which was held in Semipalatinsk, Kazakhstan on 18 June 2009. As requested in that communication, the abovementioned press release is herewith circulated for the information of all Member States

  16. Communication of 29 April 1996 received from the permanent mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for the export of nuclear material, equipment and technology

    International Nuclear Information System (INIS)

    1996-01-01

    The Director General of the International Atomic Energy Agency has received a note verbale of 29 April 1996 from the Permanent Mission of the Russian Federation providing information on the export policies and practices of the Government of the Russian Federation with respect to nuclear transfers. In light of the request expressed in the note verbale, the text of the note verbale and its attachment is being circulated

  17. Certificate for Safe Emergency Shutdown of Wind Turbines

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Svenstrup, Mikael; Pedersen, Andreas Søndergaard

    2013-01-01

    To avoid damage to a wind turbine in the case of a fault or a large wind gust, a detection scheme for emergency shutdown is developed. Specifically, the concept of a safety envelope is introduced. Within the safety envelope, the system can be shutdown without risking structural damage to the turb...

  18. Letter report seismic shutdown system failure mode and effect analysis

    International Nuclear Information System (INIS)

    KECK, R.D.

    1999-01-01

    The Supply Ventilation System Seismic Shutdown ensures that the 234-52 building supply fans, the dry air process fans and vertical development calciner are shutdown following a seismic event. This evaluates the failure modes and determines the effects of the failure modes

  19. Communication Received from the Permanent Mission of the United States of America to the International Atomic Energy Agency on Behalf of the Member States of the Nuclear Suppliers Group

    International Nuclear Information System (INIS)

    2012-01-01

    The Secretariat has received a note verbale dated 12 October 2012 from the Permanent Mission of the United States of America to the IAEA, on behalf of the Participating Governments of the Nuclear Suppliers Group (NSG). Attached to this letter is an updated version of a paper entitled 'The Nuclear Suppliers Group: Its origins, role and activities.'The original version of this paper was issued as INFCIRC/539 on 15 September 1997: revisions were issued on 17 April 2000, 16 September 2003 and 5 November 2009

  20. Communication Received from the Permanent Mission of the United States of America to the International Atomic Energy Agency on Behalf of the Member States of the Nuclear Suppliers Group

    International Nuclear Information System (INIS)

    2012-01-01

    The Secretariat has received a note verbale dated 12 October 2012 from the Permanent Mission of the United States of America to the IAEA, on behalf of the Participating Governments of the Nuclear Suppliers Group (NSG). Attached to this letter is an updated version of a paper entitled 'The Nuclear Suppliers Group: Its origins, role and activities.'The original version of this paper was issued as INFCIRC/539 on 15 September 1997: revisions were issued on 17 April 2000, 16 September 2003 and 5 November 2009 [es

  1. Communication dated 11 September 2006 from the Permanent Mission of the Republic of Kazakhstan regarding the Treaty on a Nuclear-Weapon-Free Zone in Central Asia signed on 8 September 2006

    International Nuclear Information System (INIS)

    2007-01-01

    The Secretariat has received a Note Verbale, dated 11 September 2006, from the Permanent Mission of the Republic of Kazakhstan to the IAEA regarding the Treaty on a Nuclear-Weapon-Free Zone in Central Asia signed on 8 September 2006 in Semipalatinsk by the leaders of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan. The Note Verbale and, as requested therein, the enclosed information regarding the Treaty on a Nuclear-Weapon-Free Zone in Central Asia, is reproduced herewith for the information of Member States

  2. Benefits of actinide-only burnup credit for shutdown PWRs

    International Nuclear Information System (INIS)

    Lancaster, D.; Fuentes, E.; Kang, C.; Rivard, D.

    1998-02-01

    Owners of PWRs that are shutdown prior to resolution of interim storage or permanent disposal issues have to make difficult decisions on what to do with their spent fuel. Maine Yankee is currently evaluating multiple options for spent fuel storage. Their spent fuel pool has 1,434 assemblies. In order to evaluate the value to a utility of actinide-only burnup credit, analysis of the number of canisters required with and without burnup credit was made. In order to perform the analysis, loading curves were developed for the Holtec Hi-Star 100/MPC-32. The MPC-32 is hoped to be representative of future burnup credit designs from many vendors. The loading curves were generated using the actinide-only burnup credit currently under NRC review. The canister was analyzed for full loading (32 assemblies) and with partial loadings of 30 and 28 assemblies. If no burnup credit is used the maximum capacity was assumed to be 24 assemblies. this reduced capacity is due to the space required for flux traps which are needed to sufficiently reduce the canister reactivity for the fresh fuel assumption. Without burnup credit the 1,343 assemblies would require 60 canisters. If all the fuel could be loaded into the 32 assembly canisters only 45 canisters would be required. Although the actinide-only burnup credit approach is very conservative, the total number of canisters required is only 47 which is only two short of the minimum possible number of canisters. The utility is expected to buy the canister and the storage overpack. A reasonable cost estimate for the canister plus overpack is $500,000. Actinide-only burnup credit would save 13 canisters and overpacks which is a savings of about $6.5 million. This savings is somewhat reduced since burnup credit requires a verification measurement of burnup. The measurement costs for these assemblies can be estimated as about $1 million. The net savings would be $5.5 million

  3. Supplementary shutdown system of 220 MWe standard PHWR in India

    International Nuclear Information System (INIS)

    Muktibodh, U.C.

    1997-01-01

    The design objective of the shutdown system is to make the reactor subcritical and hold it in that state for an extended period of time. This objective must be realised under all anticipated operational occurrences and postulated abnormal conditions even during most reactive state of the core. PHWR design criteria for shutdown stipulates requirement of two independent diverse and fast acting shutdown systems, either of which acting alone should meet the above objectives. This requirement would normally call for a large number of reactivity mechanism penetrations into the calandria. From the point of view of space availability at the reactivity mechanism area on top of calandria, for the relatively small core of 220 MWe PHWRs, and ease of maintenance realisation of the total worth by either of the shutdown systems acting alone was difficult. To overcome this engineering constraint and at the same time to satisfy the design criteria, a unique approach to meet the reactivity demands for shutdown was adopted. The reactivity requirements of the shutdown consists of fast and slow reactivity changes. For the shutdown system of 220 MWe PHWRs, the approach of realizing fast reactivity changes with dual redundant, diverse, fast acting shutdown systems aided by a slow acting shutdown system to counter delayed reactivity changes was conceived. The supplementary slow acting shutdown system is called upon to act after actuation of either of the two redundant fast acting systems and is referred to as Liquid Poison Injection System (LPIS). The system adds bulk amount of neutron poison (boric acid), equivalent to 45 mk, directly into the moderator through two nozzles in calandria using pneumatic pressure. This paper describes the design of LPIS as envisaged for the standardised 220 MWe PHWRs. (author)

  4. Nuclear decommissioning: A problem that won't go away

    International Nuclear Information System (INIS)

    Lenssen, N.

    1999-01-01

    The problem of shutdown reactors is growing steadily. As of the beginning of 1999, 94 reactors have been shutdown, only 429 were in operation, meaning that one out of 5.5 reactors ever built was permanently closed. Yet only a handful of these have actually been dismantled. Some countries as Japan and USA, have announced their policies that hey plan to dismantle their reactors in a decade or two after closure. Other countries like Canada or France intend to wait several decades. At the extreme United Kingdom decided to wait more than 100 years. This old shutdown reactors could become a near permanent fixture in some countries. The problem is that, the longer the reactors run, the more radioactive their interiors become, the more difficult, dangerous and expensive is to dismantle the plants, to store and bury the residual radioactive waste. Despite some early real experience with the cost of decommissioning plants, it still remains uncertain just what those costs will be and who will pay. Estimates of the dismantling cost have ranged from 10% of the initial capital investment up to 40% and even 100%. Thus, decommissioning could become the largest remaining expense facing the nuclear industry and the governments who have supported it, particularly if efforts to confine radioactive waste fail. The challenge facing the human societies is to keep nuclear waste including the shuttered plants in isolation for the many millennia that make up the hazardous life of these materials. In this light, no matter what becomes of nuclear power, the nuclear age will continue for a very long time

  5. The analysis of pressurizer safety valve stuck open accident for low power and shutdown PSA

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ho Gon; Park, Jin Hee; Jang, Seong Chul; Kim, Tae Woon

    2005-01-01

    The PSV (Pressurizer Safety Valve) popping test carried out practically in the early phase of a refueling outage has a little possibility of triggering a test-induced LOCA due to a PSV not fully closed or stuck open. According to a KSNP (Korea Standard Nuclear Power Plant) low power and shutdown PSA (Probabilistic Safety Assessment), the failure of a HPSI (High Pressure Safety Injection) following a PSV stuck open was identified as a dominant accident sequence with a significant contribution to low power and shutdown risks. In this study, we aim to investigate the consequences of the NPP for the various accident sequences following the PSV stuck open as an initiating event through the thermal-hydraulic system code calculations. Also, we search the accident mitigation method for the sequence of HPSI failure, then, the applicability of the method is verified by the simulations using T/H system code.

  6. Analysis of failure dependent test, repair and shutdown strategies for redundant trains

    International Nuclear Information System (INIS)

    Uryasev, S.; Samanta, P.

    1994-09-01

    Failure-dependent testing implies a test of a redundant components (or trains) when failure of one component has been detected. The purpose of such testing is to detect any common cause failures (CCFs) of multiple components so that a corrective action such as repair or plant shutdown can be taken to reduce the residence time of multiple failures, given a failure has been detected. This type of testing focuses on reducing the conditional risk of CCFs. Formulas for calculating the conditional failure probability of a two train system with different test, repair and shutdown strategies are developed. A methodology is presented with an example calculation showing the risk-effectiveness of failure-dependent strategies for emergency diesel generators (EDGs) in nuclear power plants (NPPs)

  7. Quality of the current low power and shutdown PSA practice

    International Nuclear Information System (INIS)

    Jang, Seung Cheol; Park, Jin Hee; Lim, Ho Gon; Kim, Tae Woon

    2004-01-01

    A probabilistic safety assessment (PSA) for the low-power and shutdown (LPSD) modes in a Korea standard nuclear power plant (KSNP) has been performed for the purpose of estimating the LPSD risk and identifying the vulnerabilities of LPSD operations. Both the operational experience and PSA results indicate that the risks from LPSD operations could be comparable with those from power operations. However, the application of the LPSD risk insights to risk-informed decision making has been slow to be adopted in practice. It is largely due to the question of whether the current LPSD PSA practice is appropriate for application to risk-informed decision making or not. Such a question has to do with the quality of the current LPSD PSA practice. In this paper, we have performed self-assessment of the KSNP LPSD PSA quality based on the ANS Standard (draft as of 13 Sep. 2002). The aims of the work are to find the LPSD PSA technical areas insufficient for application to risk-informed decision making and to efficiently allocate the limited research resources to improve the LPSD PSA model quality. Many useful findings regarding the current LPSD PSA quality are presented in this paper

  8. Reactivity initiated accidents and loss of shutdown - 20 years later

    International Nuclear Information System (INIS)

    Luxat, J.C.

    2007-01-01

    A review of the safety of Ontario's nuclear power reactors was conducted in 1987 after the Chernobyl accident. As part of this review an analysis was performed of a Loss of Coolant Accident in a Pickering A unit with coincident failure to shutdown. This analysis showed that the power excursion was halted by channel and calandria vessel failures leading to moderator fluid displacement. The containment structure did not fail and, at worst might suffer minor cracking at the top of the dome of the reactor building. Overall the dose consequences of such an accident were no worse than the limiting design basis dual failure event. In the intervening twenty years following this analysis, Significant experimental information has been obtained that relates to power pulse behaviour. This information, together with conservatisms in he original analysis, are reviewed and assessed in this paper. In addition, the issue of reactivity initiated events in other reactor types is reviewed to identify the reactor design characteristics that are of importance in these events. Contrary to popular belief the existence of positive coolant void reactivity is not as significant a factor as it is sometimes stated to be. On balance, with appropriate design measures, no one reactor type can be claimed to be 'more safe' than another. The underlying basis for this statement is articulated in this paper. (author)

  9. Reactor shutdown system of prototype fast breeder reactor

    International Nuclear Information System (INIS)

    Govindarajan, S.; Singh, Om Pal; Kasinathan, N.; Paramasivan Pillai, C.; Arul, A.J.; Chetal, S.C.

    2002-01-01

    Full text: The shutdown system of PFBR is designed to assure a very high reliability by employing well known principles of redundancy, diversity and independence. The failure probability of the shutdown system limited to -6 / ry. Salient features of the shutdown system are: Two independent shutdown systems, each of them able to accommodate an additional single failure and made up of a trip system and an associated absorber rod group. Diversity between trip systems, rods and mechanisms. Initiation of SCRAM by two diverse physical parameters of the two shutdown systems for design events leading potentially to unacceptable conditions is the core. The first group of nine rods called control and safety rods (CSR) is used for both shutdown as well as power regulation. The second group consisting of three rods known as diverse safety rods (DSR) is used only for shutdown. Diversity between the two groups is ensured by varying the operating conditions of the electromagnets and the configurations of the mobile parts. The reactivity worth of the absorber rods have been chosen such that each group of rods would ensure cold shutdown on SCRAM even when the most reactive rod of the group fails to drop. Together the two groups ensure a shutdown margin of 5000 pcm. The speed and individual rod worth of the CSR is chosen from operational and safety considerations during reactor start up and raising of power. Required drop time of rods during SCRAM depends on the incident considered. For a severe reactivity incident of 3 $/s this has to be limited to 1s and is ensured by limiting electromagnet response time and facilitating drop by gravity. Design safety limits for core components have been determined and SCRAM parameters have been identified by plant dynamic analysis to restrict the temperatures of core components within the limits. The SCRAM parameters are distributed between the two systems appropriately. Fault tree analysis of the system has been carried out to determine the

  10. COMPUTING SERVICES DURING THE ANNUAL CERN SHUTDOWN

    CERN Multimedia

    2001-01-01

    As in previous years, computing services run by IT division will be left running unattended during the annual shutdown. The following points should be noted. No interruptions are scheduled for local and wide area networking and the ACB, e-mail and unix interactive services. Unix batch services will be available but without access to manually mounted tapes. Dedicated Engineering services, general purpose database services and the Helpdesk will be closed during this period. An operator service will be maintained and can be reached at extension 75011 or by Email to computer.operations@cern.ch. Users should be aware that, except where there are special arrangements, any major problems that develop during this period will most likely be resolved only after CERN has reopened. In particular, we cannot guarantee backups for Home Directory files (for Unix or Windows) or for email folders. Any changes that you make to your files during this period may be lost in the event of a disk failure. Please note that all t...

  11. Criteria for remote shutdown for light water reactors

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    This Standard provides design criteria which require that: (1) specific controls and monitoring equipment shall be provided for achieving and maintaining the plant in a safe shutdown condition; (2) these controls be installed at a location (or locations) that is physically remote from the control room and cable spreading areas; (3) simultaneous control from both locations shall be prevented by administrative controls or devices for transfer of control from the control room to the remote location(s); and (4) the remote controls be used as defense-in-depth measure in addition to the control room shutdown controls and as a minimum shall provide for one complete channel of shutdown equipment

  12. An economic evaluation of the economics of the Rancho Seco nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Craig, P P [California Univ., Davis, CA (USA). Dept. of Applied Science; Marcus, W B [JBS Energy, Inc., Broderick, CA (USA)

    1991-03-01

    Escalating costs of operating reactors may make it economically advantageous to close them down and purchase small, cheap technologies such as combined-cycle systems. We examine the arguments pro and con for the Rancho Seco nuclear reactor, owned by the Sacramento Municipal Utility District (SMUD) and now permanently shut-down. We conclude that if the reactor could be run no better than it has run in the past, there was no clear advantage to continued operation. Optimistic scenarios show a net advantage to running it, and pessimistic scenarios show a net disadvantage. The total range of plausible costs is narrow; the financial impact of either choice on consumers would have been small. The analysis suggests that decisions on whether to close down existing reactors are highly case specific, but that strong economic arguments for shut-down can exist if reactor performance is poor and/or if maintenance expenses are high. (author).

  13. An economic evaluation of the economics of the Rancho Seco nuclear reactor

    International Nuclear Information System (INIS)

    Craig, P.P.

    1991-01-01

    Escalating costs of operating reactors may make it economically advantageous to close them down and purchase small, cheap technologies such as combined-cycle systems. We examine the arguments pro and con for the Rancho Seco nuclear reactor, owned by the Sacramento Municipal Utility District (SMUD) and now permanently shut-down. We conclude that if the reactor could be run no better than it has run in the past, there was no clear advantage to continued operation. Optimistic scenarios show a net advantage to running it, and pessimistic scenarios show a net disadvantage. The total range of plausible costs is narrow; the financial impact of either choice on consumers would have been small. The analysis suggests that decisions on whether to close down existing reactors are highly case specific, but that strong economic arguments for shut-down can exist if reactor performance is poor and/or if maintenance expenses are high. (author)

  14. Nuclear power plants

    International Nuclear Information System (INIS)

    1985-01-01

    Data concerning the existing nuclear power plants in the world are presented. The data was retrieved from the SIEN (Nuclear and Energetic Information System) data bank. The information are organized in table forms as follows: nuclear plants, its status and type; installed nuclear power plants by country; nuclear power plants under construction by country; planned nuclear power plants by country; cancelled nuclear power plants by country; shut-down nuclear power plants by country. (E.G.) [pt

  15. Fuel Supply Shutdown Facility Interim Operational Safety Requirements

    International Nuclear Information System (INIS)

    BENECKE, M.W.

    2000-01-01

    The Interim Operational Safety Requirements for the Fuel Supply Shutdown (FSS) Facility define acceptable conditions, safe boundaries, bases thereof, and management of administrative controls to ensure safe operation of the facility

  16. Italy: Analysis of Solutions for Passively Actuated Safety Shutdown Devices

    International Nuclear Information System (INIS)

    Burgazzi, L.

    2015-01-01

    This article looks at different special shutdown systems specifically engineered for prevention of severe accidents, to be implemented on Fast Reactors, with main focus on the investigation of the performance of the self-actuated shutdown systems in Sodium Fast Reactors. The passive shut-down systems are designed to shut-down system only by inherent passive reactivity feedback mechanism, under unprotected accident conditions, implying failure of reactor protection system. They are conceived to be self-actuated without any signal elaboration, since the actuation of the system is triggered by the effects induced by the transient like material dilatation, in case of overheating of the coolant for instance, according to Fast Reactor design to meet the safety requirements

  17. Startup, Shutdown, & Malfunction (SSM) Emissions at Industrial Facilities

    Science.gov (United States)

    EPA issued a final action to ensure states have plans in place that are fully consistent with the Clean Air Act and recent court decisions concerning startup, shutdown and malfunction (SSM) operations.

  18. Loss of shutdown cooling during degassing in Doel 1

    International Nuclear Information System (INIS)

    1996-01-01

    The presentation describes loss of shutdown cooling event during degassing in Doel 1 reactor, including description of Doel 1 features,status of plant prior to incident, event sequence and incident causes

  19. Safety analysis of Ignalina NPP during shutdown conditions

    International Nuclear Information System (INIS)

    Kaliatka, A.; Uspuras, E.

    2000-01-01

    The accident analysis for the Ignalina NPP with RBMK-1500 reactors at normal operating conditions and at minimum controlled power level (during startup of the reactor) has been performed in the frame of the project I n-Depth Safety Assessment of the Ignalina NPP , which was completed in 1996. However, the plant conditions during the reactor shutdown differ from conditions during reactor operation at full power (equipment status in protection systems, set points for actuation of safety and protection systems, etc.). Results of RELAP5 simulation of two worst initiating events during reactor shutdown - Pressure Header rupture in case of steam reactor cooldown as well as Pressure Header rupture in case of water reactor cooldown are discussed in the paper. Results of analysis shown that reactor are reliably cooled in both cases. Further analysis for all range of initial events during reactor shutdown and at shutdown conditions is recommended. (author)

  20. FPGA Implementation of the stepwise shutdown system

    Energy Technology Data Exchange (ETDEWEB)

    Lotjonen, L.

    2012-07-01

    This report elaborates the design process of applications for field-programmable gate array (FPGA) devices. Brief introductions to EPGA technology and the design process are first given and then the design phases are walked through with the aid of a case study. FPGA is a programmable logic device that is programmed by the customer rather than the manufacturer. They are also usually re-programmable which enables updating their programming and otherwise modifying the design. There are also one-time programmable FPGAs that can be used when security issues require it. FPGA is said to be 'hardware designed like software', which means that the design process resembles software development but the end-product is considered a hardware application because the execution of the functions is entirely different from a microprocessor. This duality can give both the flexibility of software and the reliability of hardware. The FPGA design and verification and validation (V and V) methods for NPP safety systems have not yet matured because the technology is rather new in the field. Software development methods and stanfards can be used to some extent but the hardware aspects bring new challenges that cannot be tacled using purely software methods. International efforts are being made to development formal and consistent design and V and V methodology regulations for FPGA devices. A preventive safety function called Stepwise Shutdown System (SWS) was implemented on an Actel M1 IGLOO field-programmable gate array (FPGA) device. SWS is used to drive a process into a normal state if the process measurements deviate from the desired operating values. This can happen in case of process disturbances. The SWS implementation processfrom the reguirements to the functional device is elaborated. The design is tested via simulation and hardware testing. The case study is to be further expanded as a part of a master's thesis. (orig.)

  1. FPGA Implementation of the stepwise shutdown system

    International Nuclear Information System (INIS)

    Lotjonen, L.

    2012-01-01

    This report elaborates the design process of applications for field-programmable gate array (FPGA) devices. Brief introductions to EPGA technology and the design process are first given and then the design phases are walked through with the aid of a case study. FPGA is a programmable logic device that is programmed by the customer rather than the manufacturer. They are also usually re-programmable which enables updating their programming and otherwise modifying the design. There are also one-time programmable FPGAs that can be used when security issues require it. FPGA is said to be 'hardware designed like software', which means that the design process resembles software development but the end-product is considered a hardware application because the execution of the functions is entirely different from a microprocessor. This duality can give both the flexibility of software and the reliability of hardware. The FPGA design and verification and validation (V and V) methods for NPP safety systems have not yet matured because the technology is rather new in the field. Software development methods and standards can be used to some extent but the hardware aspects bring new challenges that cannot be tackled using purely software methods. International efforts are being made to development formal and consistent design and V and V methodology regulations for FPGA devices. A preventive safety function called Stepwise Shutdown System (SWS) was implemented on an Actel M1 IGLOO field-programmable gate array (FPGA) device. SWS is used to drive a process into a normal state if the process measurements deviate from the desired operating values. This can happen in case of process disturbances. The SWS implementation process from the requirements to the functional device is elaborated. The design is tested via simulation and hardware testing. The case study is to be further expanded as a part of a master's thesis. (orig.)

  2. Summary of Information Presented at an NRC-Sponsored Low-Power Shutdown Public Workshop, April 27, 1999, Rockville, Maryland

    International Nuclear Information System (INIS)

    Wheeler, Timothy A.; Whitehead, Donnie W.; Lois, Erasmia

    1999-01-01

    This report summarizes a public workshop that was held on April 27, 1999, in Rockville, Maryland. The workshop was conducted as part of the US Nuclear Regulatory Commission's (NRC) efforts to further develop its understanding of the risks associated with low power and shutdown operations at US nuclear power plants. A sufficient understanding of such risks is required to support decision-making for risk-informed regulation, in particular Regulatory Guide 1.174, and the development of a consensus standard. During the workshop the NRC staff discussed and requested feedback from the public (including representatives of the nuclear industry, state governments, consultants, private industry, and the media) on the risk associated with low-power and shutdown operations

  3. Summary of Information Presented at an NRC-Sponsored Low-Power Shutdown Public Workshop, April 27, 1999, Rockville, Maryland

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, Timothy A.; Whitehead, Donnie W.; Lois, Erasmia

    1999-07-01

    This report summarizes a public workshop that was held on April 27, 1999, in Rockville, Maryland. The workshop was conducted as part of the US Nuclear Regulatory Commission's (NRC) efforts to further develop its understanding of the risks associated with low power and shutdown operations at US nuclear power plants. A sufficient understanding of such risks is required to support decision-making for risk-informed regulation, in particular Regulatory Guide 1.174, and the development of a consensus standard. During the workshop the NRC staff discussed and requested feedback from the public (including representatives of the nuclear industry, state governments, consultants, private industry, and the media) on the risk associated with low-power and shutdown operations.

  4. Event data collection and database development during plant shutdown and low power operations at domestic and foreign reactors

    International Nuclear Information System (INIS)

    Kim, T. Y.; Park, J. H.; Han, S. J.; Im, H. K.; Jang, S. C.

    2003-01-01

    To reduce conservatism and to obtain completeness for Low Power and ShutDown(LPSD) PSA of nuclear plants, total of 625 event data have collected during shutdown and low power operations which have occurred during about 30 years at nuclear power plants of USA and European countries including 2 domestic events. To utilize efficiently these event data, a database program which is called LEDB (Low power and shutdown Event Database) was developed and all the event data collected were inserted in that program. By reviewing and analyzing these event data various way, a lot of very useful insights and ideas for preventing similar events from reoccurrence in domestic nuclear power plants can be obtained

  5. Nuclear reactor control and shutdown device with limited travel

    International Nuclear Information System (INIS)

    Mehren, F.; Blombach, J.; Kretzen, H.H.

    1984-01-01

    The clutch for an absorber rod held in the closed position by an electromagnet with an armature is angled so that with uncontrolled lifting the clutch can be disengaged if the holding magnet current has not been removed. A switch bar controlling the clutch and connected to the magnet armature is provided with cams, which when the highest permitted end position is reached run up against a stop ring. Continuous lifting pulls the armature from the magnet by force. The relative movement produced between the switch bar and the drive bar open the clutch, and the absorber rod can fall into the fission zone. (orig./HP) [de

  6. Prevention device for rapid reactor core shutdown in BWR type reactors

    International Nuclear Information System (INIS)

    Koshi, Yuji; Karatsu, Hiroyuki.

    1986-01-01

    Purpose: To surely prevent rapid shutdown of a nuclear reactor upon partial load interruption due to rapid increase in the system frequency. Constitution: If a partial load interruption greater than the sum of the turbine by-pass valve capacity and the load setting bias portion is applied in a BWR type power plant, the amount of main steams issued from the reactor is decreased, the thermal input/output balance of the reactor is lost, the reactor pressure is increased, the void is collapsed, the neutron fluxes are increased and the reactor power rises to generate rapid reactor shutdown. In view of the above, the turbine speed signal is compared with a speed setting value in a recycling flowrate control device and the recycling pump is controlled to decrease the recycling flowrate in order to compensate the increase in the neutron fluxes accompanying the reactor power up. In this way, transient changes in the reactor core pressure and the neutron fluxes are kept within a setting point for the rapid reactor shutdown operation thereby enabling to continue the plant operation. (Horiuchi, T.)

  7. Retrofit of AECL CAN6 seals into the Pickering shutdown cooling pumps

    International Nuclear Information System (INIS)

    Rhodes, D.; Metcalfe, R.; Brown, G.

    1997-01-01

    The existing mechanical seals in the shutdown cooling (SDC) pumps at the eight-unit Pickering Nuclear Generating Station have caused as least seven forced outages in the last fifteen years. The SDC pumps were originally intended to run only during shutdowns, mostly at low pressure, except for short periods during routine testing of SDC isolation valves while the plant is operating at full pressure to verify that the emergency core injection system is available. Unfortunately, in practice, some SDC pumps must be run much more frequently than this to prevent overheating or freezing of components in the system while the plant is at power. This more severe service has decreased seal lifetime from about 8000 running hours to about 3000 running hours. Rather than tackling the difficult task of eliminating on-power running of the pumps, Pickering decided to install a more robust seal design that could withstand this. Through the process of competitive tender, AECL's CAN6 seal was chosen. This seal has a successful history in similarly demanding conditions in boiling water reactors in the USA. To supplement this and demonstrate there would be no 'surprises,' a 2000-hour test program was conducted. Testing consisted of simulating all the expected conditions, plus some special tests under abnormal conditions. This has given assurance that the seal will operate reliably in the Pickering shutdown cooling pumps. (author)

  8. Retrofit of AECL CAN6 seals into the Pickering shutdown cooling pumps

    International Nuclear Information System (INIS)

    Rhodes, D.; Metcalfe, R.; Brown, G.; Kiameh, P.; Burchett, P.

    1997-01-01

    The existing mechanical seals in the shutdown cooling (SDC) pumps at the eight-unit Pickering Nuclear Generating Station have caused at least seven forced outages in the last fifteen years. The SDC pumps were originally intended to run only during shutdowns, mostly at low pressure, except for short periods during routine testing of SDC isolation valves while the plant is operating at full pressure to verify that the emergency core injection system is available. Unfortunately, in practice, some SDC pumps must be run much more frequently than this to prevent overheating or freezing of components in the system while the plant is at power. This more severe service has decreased seal lifetime from about 8000 running hours to about 3000 running hours. Rather than tackling the difficult task of eliminating on-power running of the pumps, Pickering decided to install a more robust seal design that could withstand this. Through the process of competitive tender, AECL's CAN6 seal was chosen. This seal has a successful history in similarly demanding conditions in boiling water reactors in the USA. To supplement this and demonstrate there would be no 'surprises,' a 2000-hour test program was conducted. Testing consisted of simulating all the expected conditions, plus some special tests under abnormal conditions. This has given assurance that the seal will operate reliably in the Pickering shutdown cooling pumps. (author)

  9. Risk impact of BWR technical specifications requirements during shutdown

    International Nuclear Information System (INIS)

    Staple, B.D.; Kirk, H.K.; Yakle, J.

    1994-10-01

    This report presents an application of probabilistic models and risk based criteria for determining the risk impact of the Limiting Conditions of Operations (LCOs) in the Technical Specifications (TSs) of a boiling water reactor during shutdown. This analysis studied the risk impact of the current requirements of Allowed Outage Times (AOTs) and Surveillance Test Intervals (STIs) in eight Plant Operational States (POSs) which encompass power operations, shutdown, and refueling. This report also discusses insights concerning TS action statements

  10. Startup and shutdown of the PULSAR Tokamak Reactor

    International Nuclear Information System (INIS)

    Werley, K.A.; Bathke, C.G.

    1994-01-01

    Start-up conditions are examined for a pulsed tokamak reactor that uses only inductive plasma current drive for startup, burn and shutdown. A zero-dimensional (profile-averaged) model that describes plasma power and particle balance equations is used to study several aspects of plasma startup and shutdown, including optimization of the startup pathway tradeoff of auxiliary startup heating power versus startup time, volt-second consumtion, thermal stability and partial-power operations

  11. Marxism as permanent revolution

    NARCIS (Netherlands)

    van Ree, E.

    2013-01-01

    This article argues that the 'permanent revolution' represented the dominant element in Karl Marx and Friedrich Engels' political discourse, and that it tended to overrule considerations encapsulated in 'historical materialism'. In Marx and Engels's understanding, permanent revolution did not

  12. Communication dated 10 September 2008 received from the Permanent Mission of Egypt to the Agency concerning the High Level Policy Review Seminar of African Regional Cooperative Agreement for Research, Development and Training related to Nuclear Science and Technology (AFRA)

    International Nuclear Information System (INIS)

    2008-01-01

    The Secretariat has received a communication dated 10 September 2008 from the Permanent Mission of Egypt enclosing the documents of the High Level Policy Review Seminar of the African Regional Cooperative Agreement for Research, Development and Training related to Nuclear Science and Technology (AFRA) held in Aswan, Egypt on 28-29 November 2007. The communication, and as requested therein, the enclosures containing the Declaration of Aswan, the Aswan Action Plan and the Profile of the Regional Strategic Cooperative Framework (2008-2013) are circulated herewith for information

  13. Communication from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for transfers of nuclear-related dual-use equipment, materials, software and related technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-12-10

    The Director General of the International Atomic Energy Agency has received a Note Verbale from the Permanent Mission of the Russian Federation providing information on the export policies and practices of the Government of the Russian Federation with respect to the export of nuclear-related dual-use equipment, materials, software and related technology. In the light of the wish expressed at the end of the Note Verbale, the text of the Note Verbale is attached. The attachment to the Note Verbale was issued previously as INFCIRC/2541Rev. 4/Part 2.

  14. Communication from the Permanent Mission of the Russian Federation to the International Atomic Energy Agency regarding guidelines for transfers of nuclear-related dual-use equipment, materials, software and related technology

    International Nuclear Information System (INIS)

    2001-01-01

    The Director General of the International Atomic Energy Agency has received a Note Verbale from the Permanent Mission of the Russian Federation providing information on the export policies and practices of the Government of the Russian Federation with respect to the export of nuclear-related dual-use equipment, materials, software and related technology. In the light of the wish expressed at the end of the Note Verbale, the text of the Note Verbale is attached. The attachment to the Note Verbale was issued previously as INFCIRC/2541Rev. 4/Part 2

  15. Communication from the Permanent Missions of Brazil and Romania to the International Atomic Energy Agency Regarding Guidelines for the Transfers of Nuclear-Related Dual-Use Equipment, Materials, Software and Related Technology

    International Nuclear Information System (INIS)

    2003-01-01

    The Director General of the International Atomic Energy Agency has received Notes Verbale from the Permanent Missions of Brazil and Romania, dated 28 February 2003, providing information on the export policies and practices of the Governments of Brazil and Romania with respect to the export of nuclear-related dual-use equipment, materials, software and related technology. In the light of the wish expressed at the end of each Note Verbale, the text of the Notes Verbale is attached. The attachment referenced in the Note Verbale was issued previously as INFCIRC/254/Rev.5/Part 2

  16. Nuclear Technology Review 2015

    International Nuclear Information System (INIS)

    2015-08-01

    With 438 reactors operating at the end of 2014, nuclear energy had a global generating capacity of 376.2 GW(e). There was only one permanent shutdown. There were five new grid connections and three construction starts on new reactors. Near and long term growth prospects remained centred in Asia, particularly in China. Of the 70 reactors under construction, 46 were in Asia, as were 32 of the last 40 reactors that have been connected to the grid since 2004. Thirty countries currently use nuclear power and about the same number are considering, planning or actively working to include it as part of their energy mix. Of the 30 operating countries, 13 are either constructing new plants or actively completing previously suspended construction projects, and 12 are planning either to construct new plants or to complete suspended construction projects. Several countries that have decided to introduce nuclear power are at advanced stages of infrastructure preparation. The IAEA’s 2014 projections show a growth between 8% and 88% in nuclear power capacity by the year 2030. Growth of population and demand for electricity in the developing world, recognition of the role nuclear power plays in reducing greenhouse gas emissions, the importance of security of energy supply and the volatility of fossil fuel prices point to nuclear energy playing an important role in the energy mix in the long run. Safety improvements have continued to be made at nuclear power plants (NPPs) throughout the world. These have included identifying and applying lessons learned from the accident at the Fukushima Daiichi Nuclear Power Plant, improving the effectiveness of defence in depth, strengthening emergency preparedness and response capabilities, enhancing capacity building, and protecting people and the environment from ionizing radiation

  17. Basis for Interim Operation for Fuel Supply Shutdown Facility

    International Nuclear Information System (INIS)

    BENECKE, M.W.

    2003-01-01

    This document establishes the Basis for Interim Operation (BIO) for the Fuel Supply Shutdown Facility (FSS) as managed by the 300 Area Deactivation Project (300 ADP) organization in accordance with the requirements of the Project Hanford Management Contract procedure (PHMC) HNF-PRO-700, ''Safety Analysis and Technical Safety Requirements''. A hazard classification (Benecke 2003a) has been prepared for the facility in accordance with DOE-STD-1027-92 resulting in the assignment of Hazard Category 3 for FSS Facility buildings that store N Reactor fuel materials (303-B, 3712, and 3716). All others are designated Industrial buildings. It is concluded that the risks associated with the current and planned operational mode of the FSS Facility (uranium storage, uranium repackaging and shipment, cleanup, and transition activities, etc.) are acceptable. The potential radiological dose and toxicological consequences for a range of credible uranium storage building have been analyzed using Hanford accepted methods. Risk Class designations are summarized for representative events in Table 1.6-1. Mitigation was not considered for any event except the random fire event that exceeds predicted consequences based on existing source and combustible loading because of an inadvertent increase in combustible loading. For that event, a housekeeping program to manage transient combustibles is credited to reduce the probability. An additional administrative control is established to protect assumptions regarding source term by limiting inventories of fuel and combustible materials. Another is established to maintain the criticality safety program. Additional defense-in-depth controls are established to perform fire protection system testing, inspection, and maintenance to ensure predicted availability of those systems, and to maintain the radiological control program. It is also concluded that because an accidental nuclear criticality is not credible based on the low uranium enrichment

  18. A Study on the Risk Reduction Effect by MLCS (Mid-loop Level Control System) of EUAPR using the Low-Power and Shutdown PSA Result

    International Nuclear Information System (INIS)

    Lee, Keunsung; Choi, Sunmi; Kim, Eden

    2016-01-01

    The EU-APR design has been developed in order to expand and diversify the global nuclear power market of APR1400. For the improvement of shutdown risk for the EUAPR, the mid-loop level control system (MLCS) is considered during mid-loop operation for the EU-APR, which is not incorporated into SKN 3 and 4 (APR1400 Type) in Korea. Commonly, the risk associated with the NPP can be identified through the PSA. Thus, this paper discusses the low power and shutdown (LPSD) risk reduction effect by MLCS using the Low-Power and Shutdown PSA Result. LPSD level 1 PSA models for EU-APR have been developed. The risk reduction effect by MLCS is discussed. Because the loss of shutdown cooling function during mid-loop is one of the most vulnerable events, the MLCS have a significant influence on CDF in LPSD PSA. The shutdown risk of domestic power plants would likely be reduced if the MLCS is adopted in all operating NPPs in Korea during the mid-loop operation. It is expected that this work will contribute to reduce shutdown risk of domestic power plants

  19. Communication Received from the Permanent Mission of the United States of America to the International Atomic Energy Agency regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Secretariat has received a note verbale from the Permanent Mission of the United States of America, dated 12 October 2012, in which it requests that the Agency circulates, to all Member States, a letter of 5 September 2012 from the Chairman of the Nuclear Suppliers Group, Mr Richard J.K. Stratford, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments' Guidelines for Nuclear Transfers

  20. Communication Received from the Permanent Mission of the United States of America to the International Atomic Energy Agency regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Secretariat has received a note verbale from the Permanent Mission of the United States of America, dated 12 October 2012, in which it requests that the Agency circulates, to all Member States, a letter of 5 September 2012 from the Chairman of the Nuclear Suppliers Group, Mr Richard J.K. Stratford, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments’ Guidelines for Nuclear Transfers [es

  1. Communication Received from the Permanent Mission of the United States of America to the International Atomic Energy Agency regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Secretariat has received a note verbale from the Permanent Mission of the United States of America, dated 12 October 2012, in which it requests that the Agency circulates, to all Member States, a letter of 5 September 2012 from the Chairman of the Nuclear Suppliers Group, Mr Richard J.K. Stratford, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments’ Guidelines for Nuclear Transfers

  2. Reactor safety review of permanent changes

    International Nuclear Information System (INIS)

    Lam, K.F.

    1997-01-01

    Operational compliance engineers review all changes as part of a change control process. Each change, permanent or temporary, is required to undergo an intricate review process to ensure that the benefits associated with the change outweigh the risk. For permanent changes, it is necessary to ensure that the proposed design meets the nuclear safety requirements, conforms to the licensing requirements and complies with regulatory requirements. In addition, during installation of the permanent change and prior to in-service, a configuration management process is in place to align the change with operating and maintenance documents. (author)

  3. Study on the identification of main drivers affecting the performance of human operators during low power and shutdown operation

    International Nuclear Information System (INIS)

    Kim, Ar Ryum; Park, Jinkyun; Kim, Ji Tae; Kim, Jaewhan; Seong, Poong Hyun

    2016-01-01

    Highlights: • The performance of human operator during LPSD operation is significantly important. • Human performance is affected by drivers such as procedure, training, and etc. • Main drivers during LPSD operation at domestic NPPs were suggested. • It is expected that it will be used for estimating human reliability during LPSD operation. - Abstract: In the past, many researchers believed that a reactor during low power and shutdown operation was sufficiently safe. This belief has been changed by the number of accidents during such types of operation, which is significantly high. Also, it was pointed out that one of the main differences between low power and shutdown operation and full power operation is the significance of human action because there are huge amounts of human actions due to extensive maintenance and testing while automatic control and safety functions may be disabled and procedures are insufficient or incomplete. This paper suggests the main drivers in performing human reliability analysis. For this study, we reviewed eight reports relating to human performance during low power and shutdown operation and applied a root cause analysis method for 53 human or human-related events at domestic nuclear power plants to derive the main drivers that affect the occurrence of those events. As a result, several main drivers were derived, such as procedures, training, experience of personnel, and workload/stress. It is expected that these main drivers will be used to perform human reliability analysis for low power and shutdown operation.

  4. The Alternative Design Features for Safety Enhancement in Shutdown Operation

    International Nuclear Information System (INIS)

    Oh, Hae Cheol; Kim, Myung Ki; Chung, Bag Soon; Seo, Mi Ro

    2009-01-01

    PSA can be used to confirm that the new plant design is complied with the applicable safety goals, and to select among the alternate design options. A shutdown PSA provides insight for outage planning schedule, outage management practices, and design modifications. Considering the results of both LPSD PSA studies and operating experiences for low power and shutdown, the improvements can be proposed to reduce the high risk contribution. The improvements/enhancements during shutdown operation may be divided into categories such as hardware, administrative management, and operational procedure. This paper presents on an example how the risk related to an accidental situation can be reduced, focusing the hardware design changes for the newly designed NPPs

  5. CV activities on the LHC complex during the long shutdown

    CERN Document Server

    Deleval, S; Body, Y; Obrecht, M; Moccia, S; Peon, G

    2011-01-01

    The presentation gives an overview of the major projects and work foreseen to be performed during next long shutdown on cooling and ventilation plants. Several projects are needed following the experience of the last years when LHC was running, in particular the modifications in the water cooling circuits presently in overflow. Some other projects are linked to the CV consolidation plan. Finally, most of the work shall be done to respond to additional requests: SR buildings air conditioning, the need to be able to clean and maintain the LHC cooling towers without a complete stop of cooling circuits, the upgrade of the air conditioning of the CCC rack room cooling etc. For all these activities, the author will detail constraints and the impact on the schedule and on the operation of the plants that will however need to run for most of the shutdown duration. The consequence of postponing the long shutdown from 2012 to 2013 will be also covered.

  6. The permanent process

    DEFF Research Database (Denmark)

    Møller, Jesper; McCullagh, Peter

    We extend the boson process first to a large class of Cox processes and second an even larger class of infinitely divisible point processes. Density and moment results are studied in detail. These results are obtained in closed form as weighted permanents, so the extension is called a permanent...... process. Temporal extensions and a particularly tractable case of the permanent process are also studied. Extensions of the ferminon process along similar lines, leading to so-called determinant processes, are discussed at the end. While the permanent process is attractive, the determinant process...

  7. Control rod drive of nuclear reactor

    International Nuclear Information System (INIS)

    Zhuchkov, I.I.; Gorjunov, V.S.; Zaitsev, B.I.

    1980-01-01

    This invention relates to nuclear reactors and, more particularly, to a drive of a control rod of a nuclear reactor and allows power control, excess reactivity compensation, and emergency shut-down of a reactor. (author)

  8. Core shutdown report: Subcycle K-14.1

    International Nuclear Information System (INIS)

    Gough, S.T.

    1992-05-01

    When a reactor is shut down, there is a set of rules that must be followed to guarantee that the reactor remains in a safe shutdown state. Some of these rules involve the cooling of heat generating assemblies before, during, and after charge-discharge (C ampersand D) operations. These rules ensure that C ampersand D operations will not endanger the integrity of the fuel or targets by allowing them to overheat. DPSOL 105-1225, Assembly Discharge and Forced Cooling Requirements, is the primary operations procedure that governs these cooling rules. The specific shutdown cooling limits that are input into this procedure are contained within this report

  9. Study on secondary shutdown systems in Tehran research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, H.R.; Fadaei, A.H., E-mail: Fadaei_amir@aut.ac.ir; Gharib, M.

    2015-09-15

    Highlights: • A study was undertaken to summarize the techniques for secondary shutdown systems (SSS). • Neutronic calculation performed for proposed systems as SSS. • Dumping the heavy water stored in the reflector vessel is capable to shut down reactor. • Neutronic and transient calculation was done for validating the selected SSS. • All calculation shown that this system has advantages in safety and neutron economy. - Abstract: One important safety aspect of any research reactor is the ability to shut down the reactor. Usually, research reactors, currently in operation, have a single shutdown system based on the simultaneous insertion of the all control rods into the reactor core through gravity. Nevertheless, the International Atomic Energy Agency currently recommends use of two shutdown systems which are fully independent from each other to guarantee secure shutdown when one of them fails. This work presents an investigative study into secondary shutdown systems, which will be an important safety component in the research reactor and will provide another alternative way to shut down the reactor emergently. As part of this project, a study was undertaken to summarize the techniques that are currently used at world-wide research reactors for recognizing available techniques to consider in research reactors. Removal of the reflector, removal of the fuels, change in critical shape of reactor core and insertion of neutron absorber between the core and reflector are selected as possible techniques in mentioned function. In the next step, a comparison is performed for these methods from neutronic aspects. Then, chosen method is studied from the transient behavior point of view. Tehran research reactor which is a 5 MW open-pool reactor selected as a case study and all calculations are carried out for it. It has 5 control rods which serve the purpose of both reactivity control and shutdown of reactor under abnormal condition. Results indicated that heavy

  10. Modelling the fluid structure interaction produced by a waterhammer during shutdown of high-pressure pumps

    International Nuclear Information System (INIS)

    Erath, W.; Nowotny, B.; Maetz, J.

    1999-01-01

    Measurements of an experiment in a pipe system with pump shutdown and valve closing have been performed in the nuclear power plant KRB II (Gundremmingen, Germany). Comparative calculations of fluid and structure including interaction show an excellent agreement with the measured results. Theory and implementation of the fluid structure interaction (FSI) and the results of the comparison are described. The following measurements have been compared with calculations: (1) experiments in Delft, Netherlands to analyse the FSI; and (2) experiment with pump shutdown and valve closing in the nuclear power plant KRB II has been performed. It turns out, that the consideration of the FSI is necessary for an exact calculation of 'soft' piping systems. It has significant application in current waterhammer problems. For example, water column closure, vapour collapse, check valve slamming continues to create waterhammers in the energy industry. An important consequence of the FSI is mostly a significant increase of the effective structural damping. This mitigates - so far in all KED's calculations the FSI has taken into account - an amplification of pipe movements due to pressure waves in resonance with structural eigenvalues. To investigate the integrity of pipe systems pipe stresses are calculated. Taking FSI into account they are reduced by 10-40% in the actual case. (orig.)

  11. Communication Received from the Permanent Mission of Mexico to the International Atomic Energy Agency Regarding Guidelines for the Export of Nuclear Material, Equipment and Technology and the Guidelines for Transfers of Nuclear-related Dual-use Equipment, Materials, Software and Related Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Director General has received a note verbale dated 15 June 2012 from the Permanent Mission of Mexico to the International Atomic Energy Agency providing information on the decision of the Government of Mexico to act in accordance with the 'Guidelines for the Export of Nuclear Material, Equipment and Technology', issued as document INFCIRC/254/Rev.10/Part 1, including its Annexes, and with the 'Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Material, Software and Related Technology', issued as document INFCIRC/254/Rev.8/Part 2

  12. Communication Received from the PermanentMission of Mexico to the International Atomic Energy Agency Regarding Guidelines for the Export of Nuclear Material, Equipment and Technology and the Guidelines for Transfers of Nuclear-related Dual-use Equipment, Materials, Software and Related Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Director General has received a note verbale dated 15 June 2012 from the Permanent Mission of Mexico to the International Atomic Energy Agency providing information on the decision of the Government of Mexico to act in accordance with the 'Guidelines for the Export of Nuclear Material, Equipment and Technology', issued as document INFCIRC/254/Rev.10/Part 1, including its Annexes, and with the 'Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Material, Software and Related Technology', issued as document INFCIRC/254/Rev.8/Part 2

  13. Communication Received from the Permanent Mission of the Republic of Serbia to the International Atomic Energy Agency Regarding Guidelines for the Export of Nuclear Material, Equipment and Technology and the Guidelines for Transfers of Nuclear-related Dual-use Equipment, Materials, Software and Related Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Director General has received a note verbale dated 28 September 2012 from the Permanent Mission of Serbia to the International Atomic Energy Agency providing information on the decision of the Government of Serbia to adhere to the 'Guidelines for the Export of Nuclear Material, Equipment and Technology', issued as document INFCIRC/254/Rev.10/Part 1, including its Annexes, and with the 'Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Material, Software and Related Technology', issued as document INFCIRC/254/Rev.8/Part 2 [fr

  14. Communication Received from the PermanentMission of Mexico to the International Atomic Energy Agency Regarding Guidelines for the Export of Nuclear Material, Equipment and Technology and the Guidelines for Transfers of Nuclear-related Dual-use Equipment, Materials, Software and Related Technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-06-19

    The Director General has received a note verbale dated 15 June 2012 from the Permanent Mission of Mexico to the International Atomic Energy Agency providing information on the decision of the Government of Mexico to act in accordance with the 'Guidelines for the Export of Nuclear Material, Equipment and Technology', issued as document INFCIRC/254/Rev.10/Part 1, including its Annexes, and with the 'Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Material, Software and Related Technology', issued as document INFCIRC/254/Rev.8/Part 2.

  15. Communication Received from the Permanent Mission of Mexico to the International Atomic Energy Agency Regarding Guidelines for the Export of Nuclear Material, Equipment and Technology and the Guidelines for Transfers of Nuclear-related Dual-use Equipment, Materials, Software and Related Technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-06-19

    The Director General has received a note verbale dated 15 June 2012 from the Permanent Mission of Mexico to the International Atomic Energy Agency providing information on the decision of the Government of Mexico to act in accordance with the 'Guidelines for the Export of Nuclear Material, Equipment and Technology', issued as document INFCIRC/254/Rev.10/Part 1, including its Annexes, and with the 'Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Material, Software and Related Technology', issued as document INFCIRC/254/Rev.8/Part 2.

  16. Communication Received from the Permanent Mission of the Republic of Serbia to the International Atomic Energy Agency Regarding Guidelines for the Export of Nuclear Material, Equipment and Technology and the Guidelines for Transfers of Nuclear-related Dual-use Equipment, Materials, Software and Related Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Director General has received a note verbale dated 28 September 2012 from the Permanent Mission of Serbia to the International Atomic Energy Agency providing information on the decision of the Government of Serbia to adhere to the 'Guidelines for the Export of Nuclear Material, Equipment and Technology', issued as document INFCIRC/254/Rev.10/Part 1, including its Annexes, and with the 'Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Material, Software and Related Technology', issued as document INFCIRC/254/Rev.8/Part 2 [es

  17. Communication Received from the Permanent Mission of the Republic of Serbia to the International Atomic Energy Agency Regarding Guidelines for the Export of Nuclear Material, Equipment and Technology and the Guidelines for Transfers of Nuclear-related Dual-use Equipment, Materials, Software and Related Technology

    International Nuclear Information System (INIS)

    2012-01-01

    The Director General has received a note verbale dated 28 September 2012 from the Permanent Mission of Serbia to the International Atomic Energy Agency providing information on the decision of the Government of Serbia to adhere to the 'Guidelines for the Export of Nuclear Material, Equipment and Technology', issued as document INFCIRC/254/Rev.10/Part 1, including its Annexes, and with the 'Guidelines for Transfers of Nuclear-Related Dual-Use Equipment, Material, Software and Related Technology', issued as document INFCIRC/254/Rev.8/Part 2

  18. Maintenance implementation plan for fuel supply shutdown

    International Nuclear Information System (INIS)

    Stephenson, R.L.

    1995-06-01

    This Maintenance Implementation Plan is written to satisfy the requirements of DOE Order 4330.4B, ''MAINTENANCE MANAGEMENT PROGRAM'', that specifies the general policy and objectives for the establishment of DOE controlled maintenance programs. These Programs provide for the management and performance of cost-effective maintenance and repair of Department of Energy (DOE) property, which includes facilities. A review of DOE Order 4330.4B, particularly Chapter II the nuclear portion, against existing WHC site programs and policies has provided assurance that most requirements of this order have already been implemented by existing WHC programs. Applicable requirements and guidelines of 4330.4B that are deficient or not implemented are presently being developed and implemented through WHC site policies and programs. Where no program is presently identified or being developed for 4330.4B requirements, responsibility for implementation has been assigned within this plan

  19. Fuel supply shutdown facility interim operational safety requirements

    International Nuclear Information System (INIS)

    Besser, R.L.; Brehm, J.R.; Benecke, M.W.; Remaize, J.A.

    1995-01-01

    These Interim Operational Safety Requirements (IOSR) for the Fuel Supply Shutdown (FSS) facility define acceptable conditions, safe boundaries, bases thereof, and management or administrative controls to ensure safe operation. The IOSRs apply to the fuel material storage buildings in various modes (operation, storage, surveillance)

  20. 300 Area fuel supply shutdown facility hazards assessment

    International Nuclear Information System (INIS)

    Campbell, L.R.

    1998-01-01

    This document establishes the technical basis in support of Emergency Planning activities for the 300 Area Fuel Supply Shutdown Facilities on the Hanford Site. Through this document, the technical basis for the development of facility specific Emergency Action Levels and Emergency Planning Zone, is demonstrated

  1. Small leak shutdown, location, and behavior in LMFBR steam generators

    International Nuclear Information System (INIS)

    Sandusky, D.W.

    1976-01-01

    The paper summarizes an experimental study of small leaks tested under LMFBR steam generator conditions. Defected tubes were exposed to flowing sodium and steam. The observed behavior of the defected tubes is reported along with test results of shutdown methods. Leak location methods were investigated. Methods were identified to open plugged defects for helium leak testing and detect plugged leaks by nondestructive testing

  2. Operating and maintenance experience of Dhruva secondary shutdown system

    International Nuclear Information System (INIS)

    Sharma, U.L.; Bharathan, R.

    1997-01-01

    Nine numbers of cadmium shut-off rods are used as primary fast acting shutdown devices while moderator dumping is used as secondary shutdown system. The secondary shutdown system in Dhruva reactor comprises of 3 dump valves and 3 control valves. Under normal operations, the control valves are used to control the moderator level and thereby the reactor power. Under Trip conditions the dump valves as well as the control valves open fully, dumping the moderator to the dump tank, thereby acting as secondary shutdown devices. While the failure of any of these valves to close fully is an incident, the failure of any of these valves to open on a demand is a safety related unusual occurrence and needs to be viewed seriously. During the last 11 years of operation of these valves, there was one incidence of a valve not closing fully and there were two instances of a valve not opening fully on demand. The possible causes, the corrective action taken to rehabilitate these valves and the elaborate system preparations undertaken to enable maintenance jobs are described. (author)

  3. Summary of Session 5 and 6 'Long Shutdown 1'

    Energy Technology Data Exchange (ETDEWEB)

    Bordry, F; Foraz, K [European Organization for Nuclear Research, Geneva (Switzerland)

    2012-07-01

    This paper summarizes the sessions devoted to Long Shutdown 1 (LS1) in the LHC, injectors and experiments. The time frame and start date were discussed, with the main activities from powering tests prior to warm-up up to physics were presented. The session finished with a discussion on the maximum reasonable energy. (author)

  4. Reactor Shutdown Mechanism by Top-mounted Hydraulic System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Haun; Cho, Yeong Garp; Choi, Myoung Hwan; Lee, Jin Haeng; Huh, Hyung; Kim, Jong In [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    There are two types of reactor shutdown mechanisms in HANARO. One is the mechanism driven by a hydraulic system, and the other is driven by a stepping motor. In HANARO, there are four Control Rod Drive Mechanisms (CRDMs) with an individual step motor and four Shutoff (SO) Units with an individual hydraulic system located at the top of reactor pool. The absorber rods in SO units are poised at the top of the core by the hydraulic force during normal operation. The rods of SO units drop by gravity as the first reactor showdown mechanism when a trip is commended by the reactor protection system (RPS). The rods in CRDMs also drop by gravity together as a redundant shutdown mechanism. When a trip is commended by the reactor regulating system (RRS), the absorber rods of CRDM only drop; while the absorber rods of SO units stay at the top of the core by the hydraulic system. The reactivity control mechanisms of in JRTR, one of the new research reactor with plate type fuels, consist of four CRDMs driven by an individual step motor and two second shutdown drive mechanisms (SSDMs) driven by an individual hydraulic system as shown in Fig. 1. The CRDMs act as the first reactor shutdown mechanism and reactor regulating as well. The top-mounted SSDM driven by the hydraulic system for the JRTR is under design in KAERI. The SSDM provides an alternate and independent means of reactor shutdown. The second shutdown rods (SSRs) of the SSDM are poised at the top of the core by the hydraulic system during the normal operation and drop by gravity for the reactor trip. Based on the proven technology of the design, operation and maintenance for HANARO, the SSDM for the JRTR has been optimized by the design improvement from the experience and test. This paper aims for the introduction of the SSDM in the process of the basic design. The major differences of the shutdown mechanisms by the hydraulic system are compared between HANARO and JRTR, and the design features, system, structure and

  5. Management of accidental scenarios involving the loss of RHRS under shutdown conditions

    International Nuclear Information System (INIS)

    Serradell, V.; Villanueva, J.F.; Martorell, S.; Carlos, S.; Pelayo, F.; Mendizabal, R.; Sol, I.

    2009-01-01

    Results from current Probabilistic Safety Assessment studies of Nuclear Power Plants show the importance of some risky scenarios with the plant at low power and shutdown conditions as compared to the accident scenarios with the plant operating at full power. Technical Specifications establish the Limiting Conditions for operation to assure the plant integrity in each Plant Operational State (POS). Moreover, the plant configuration may differ from the beginning to the end of a certain Plant Operational State, so the Limiting Conditions for Operation (LCO) established could be revised as, depending on the plant configuration, the transient evolution may be slightly different. For a PWR plant, one of the most risky accidental sequences in shutdown is the loss of the residual heat removal system, Using the information provided by the plant low power probabilistic safety analysis (LPSA), which should address the Limiting Conditions for Operation imposed by the current Technical Specification, two situations are distinguished: Main Reactor Cooling System (RCS) fully filled with water and RCS partially filled. In addition, while the primary system is partially filled in Cold Shutdown, two different plant configurations can be distinguished, which depend on the particular POS: RCS open and closed. For each case, the corresponding Technical Specification establishes the path to evacuate the residual heat generated. This paper explores the possibility of having alternative or complementary sources for heat removal others than the ones established in the Technical Specification. Especial attention is paid to the role of Steam Generators as an effective heat sink and the possibility of restart of the redundant RHR train. Such alternatives will influence LPSA implementation results. To perform this analysis the loss of the RHR system in a PWR plant has been simulated using RELAP-5 considering the plant in different plant operational states. One of the main results of this work

  6. Elementary calculation of the shutdown delay of a pile; Calcul elementaire de la periode d'extinction d'une pile

    Energy Technology Data Exchange (ETDEWEB)

    Yvon, J

    1949-04-01

    This study analyzes theoretically the progress of the shutdown of a nuclear pile (reactor) when a cadmium rod is introduced instantaneously. For simplification reasons, the environment of the pile is considered as homogenous and only thermal neutrons are considered (delayed neutrons are neglected). Calculation is made first for a plane configuration (plane vessel, plane multiplier without reflector, and plane multiplier with reflector), and then for a cylindrical configuration (multiplier without reflector, multiplier with infinitely thick reflector, finite cylindrical piles without reflector and with reflector). The self-sustain conditions are calculated for each case and the multiplication length and the shutdown delay are deduced. (J.S.)

  7. Safety considerations for research reactors in extended shutdown

    International Nuclear Information System (INIS)

    2004-01-01

    According to the IAEA Research Reactor Database, in the last 20 years, 367 research reactors have been shut down. Of these, 109 have undergone decommissioning and the rest are in extended shutdown with no clear definition about their future. Still other research reactors are infrequently operated with no meaningful utilization programme. These two situations present concerns related to safety such as loss of corporate memory, personnel qualification, maintenance of components and systems and preparation and maintenance of documentation. There are many reasons to shut down a reactor; these may include: - the need to carry out modifications in the reactor systems; - the need for refurbishment to extend the lifetime of the reactor; - the need to repair reactor structures, systems, or components; - the need to remedy technical problems; - regulatory or public concerns; - local conflicts or wars; - political convenience; - the lack of resources. While any one of these reasons may lead to shutdown of a reactor, each will present unique problems to the reactor management. The large variations from one research reactor to the next also will contribute to the uniqueness of the problems. Any option that the reactor management adopts will affect the future of the facility. Options may include dealing with the cause of the shutdown and returning to normal operation, extending the shutdown period waiting a future decision, or decommissioning. Such options are carefully and properly analysed to ensure that the solution selected is the best in terms of reactor type and size, period of shutdown and legal, economic and social considerations. This publication provides information in support of the IAEA safety standards for research reactors

  8. Communication of 10 January 2008 received from the Permanent Mission of the United Kingdom regarding the Export of Nuclear Material and of Certain Categories of Equipment and Other Material

    International Nuclear Information System (INIS)

    2008-01-01

    The Director General has received a note ver bale from the Permanent Mission of the United Kingdom, dated 10 January 2008, in which it requests that the Agency circulate to all Member States a letter of 12 December 2006 from the Chairman of the Zangger Committee, Mr. Pavel Klucky, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belgium, Bulgaria, Canada, China, Croatia, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Republic of Korea, Luxemburg, the Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, concerning the export of nuclear material and of certain categories of equipment and other material [es

  9. Communication of 2 June 2009 received from the Permanent Mission of the United Kingdom regarding the Export of Nuclear Material and of Certain Categories of Equipment and Other Material

    International Nuclear Information System (INIS)

    2009-01-01

    The Director General has received a note ver bale from the Permanent Mission of the United Kingdom, dated 2 June 2009, in which it requests that the Agency circulate to all Member States a letter of 28 May 2009 from the Chairman of the Zangger Committee, Mr. Pavel Klucky, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belgium, Bulgaria, Canada, China, Croatia, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Kazakhstan, the Republic of Korea, Luxemburg, the Netherlands, Norway, Poland, Portugal, Romania, the Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom and the United States of America, concerning a number of corrections to the communication regarding the export of nuclear material and of certain categories of equipment and other material published in INFCIRC/209/Rev.2 [fr

  10. Communication of 10 January 2008 received from the Permanent Mission of the United Kingdom regarding the Export of Nuclear Material and of Certain Categories of Equipment and Other Material

    International Nuclear Information System (INIS)

    2008-01-01

    The Director General has received a note ver bale from the Permanent Mission of the United Kingdom, dated 10 January 2008, in which it requests that the Agency circulate to all Member States a letter of 12 December 2006 from the Chairman of the Zangger Committee, Mr. Pavel Klucky, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belgium, Bulgaria, Canada, China, Croatia, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Republic of Korea, Luxemburg, the Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, concerning the export of nuclear material and of certain categories of equipment and other material [fr

  11. Communication of 2 June 2009 received from the Permanent Mission of the United Kingdom regarding the Export of Nuclear Material and of Certain Categories of Equipment and Other Material

    International Nuclear Information System (INIS)

    2009-01-01

    The Director General has received a note ver bale from the Permanent Mission of the United Kingdom, dated 2 June 2009, in which it requests that the Agency circulate to all Member States a letter of 28 May 2009 from the Chairman of the Zangger Committee, Mr. Pavel Klucky, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belgium, Bulgaria, Canada, China, Croatia, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Kazakhstan, the Republic of Korea, Luxemburg, the Netherlands, Norway, Poland, Portugal, Romania, the Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom and the United States of America, concerning a number of corrections to the communication regarding the export of nuclear material and of certain categories of equipment and other material published in INFCIRC/209/Rev.2 [ru

  12. Communication of 10 January 2008 received from the Permanent Mission of the United Kingdom regarding the Export of Nuclear Material and of Certain Categories of Equipment and Other Material

    International Nuclear Information System (INIS)

    2008-01-01

    The Director General has received a note ver bale from the Permanent Mission of the United Kingdom, dated 10 January 2008, in which it requests that the Agency circulate to all Member States a letter of 12 December 2006 from the Chairman of the Zangger Committee, Mr. Pavel Klucky, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belgium, Bulgaria, Canada, China, Croatia, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Republic of Korea, Luxemburg, the Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, concerning the export of nuclear material and of certain categories of equipment and other material [ru

  13. Communication of 2 June 2009 received from the Permanent Mission of the United Kingdom regarding the Export of Nuclear Material and of Certain Categories of Equipment and Other Material

    International Nuclear Information System (INIS)

    2009-01-01

    The Director General has received a note ver bale from the Permanent Mission of the United Kingdom, dated 2 June 2009, in which it requests that the Agency circulate to all Member States a letter of 28 May 2009 from the Chairman of the Zangger Committee, Mr. Pavel Klucky, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belgium, Bulgaria, Canada, China, Croatia, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Kazakhstan, the Republic of Korea, Luxemburg, the Netherlands, Norway, Poland, Portugal, Romania, the Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom and the United States of America, concerning a number of corrections to the communication regarding the export of nuclear material and of certain categories of equipment and other material published in INFCIRC/209/Rev.2 [es

  14. Enhancing Efficiency of Safeguards at Facilities that are Shutdown or Closed-Down, including those being Decommissioned

    Energy Technology Data Exchange (ETDEWEB)

    Moran, B. [Brookhaven National Lab. (BNL), Upton, NY (United States); Stern, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Colley, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Marzo, M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-12-15

    International Atomic Energy Agency (IAEA) safeguards involves verification activities at a wide range of facilities in a variety of operational phases (e.g., under construction, start-up, operating, shutdown, closed-down, and decommissioned). Safeguards optimization for each different facility type and operational phase is essential for the effectiveness of safeguards implementation. The IAEA’s current guidance regarding safeguards for the different facility types in the various lifecycle phases is provided in its Design Information Examination (DIE) and Verification (DIV) procedure. 1 Greater efficiency in safeguarding facilities that are shut down or closed down, including those being decommissioned, could allow the IAEA to use a greater portion of its effort to conduct other verification activities. Consequently, the National Nuclear Security Administration’s Office of International Nuclear Safeguards sponsored this study to evaluate whether there is an opportunity to optimize safeguards approaches for facilities that are shutdown or closed-down. The purpose of this paper is to examine existing safeguards approaches for shutdown and closed-down facilities, including facilities being decommissioned, and to seek to identify whether they may be optimized.

  15. Advance and permanent public information

    International Nuclear Information System (INIS)

    d'Oleon, C.

    1990-01-01

    The accident at CHERNOBYL highlighted one of the major problems facing the nuclear industry at present and during the years to come: the need to provide information. There are two aspects to this requirement: information at a time of crisis issued when an accident such as that at CHERNOBYL takes place, but which has to be based on a procedure set up before the crisis, and advance and permanent information which prepares the ground for information at a time of crisis. The requirement for information is of particular importance in France, given the preponderance of nuclear energy in the electricity generating industry. The procedure covers the principles which were forcefully asserted by the French public authorities during the CHERNOBYL crisis, the resources strengthened or established at that time, and finally, the introduction of a policy of wider-ranging communication which is based on the idea that one can never compromise with safety

  16. Recent experience about the influence of primary coolant and shutdown chemistry on cobalt activity at Beznau NPP

    International Nuclear Information System (INIS)

    Mailand, I.; Venz, H.

    2007-01-01

    The Beznau nuclear power plant comprises two identical 380 MWe PWR units, commissioned in 1969 and 1971. The surfaces of the new steam generator tube material, Inconel 690, are the main source of 58 Co. The 60 Co originates predominantly from the Cobalt alloy, Stellite, which is installed in valves and pump bearings because of the very good hardness of this material. By means of optimised shutdown chemistry it is possible to reduce the amount of NiO on the fuel rods, leading to reduced Co-58 peaks in subsequent cycles. The optimised shutdown chemistry during the past few years and especially the strict separation of acid-reducing phase from the acid-oxidising phase as well as the results of studies and the resulting operational experiences are important basics for the actual operation mode of the Beznau NPP. (orig.)

  17. Nuclear Waste Fund management

    International Nuclear Information System (INIS)

    Hobart, L.

    1984-01-01

    The Nuclear Waste Fund involves a number of features which make it a unique federal program. Its primary purpose is to finance one of the largest and most controversial public works programs in the history of the United States. Despite the program's indicated size and advance publicity, no one knows exactly where the anticipated projects will be built, who will construct them, what they will look like when they are done or how they will be operated and by whom. Implimentation of this effort, if statutory targets are actually met, covers a 16-year period. To cover the costs of the program, the Federal Government will tax nuclear power at the rate of 1 mil per kilowatt hour generated. This makes it one of the biggest and longest-lived examples of advance collections for construction work in progress in the history of the United States. While the Department of Energy is authorized to collect funds for the program the Nuclear Regulatory Commission has the authority to cut off this revenue stream by the shutdown of particular reactors or particular reactor types. If all goes well, the Federal Government will begin receiving spent nuclear fuel by 1998, continuing to assess a fee which will cover operating and maintenance costs. If all does not go well, the Federal Government and/or utilities will have to take other steps to solve the problem of permanent disposal. Should the latter circumstance prevail, presumably not only used to date but the $7.5 billion would be spent. The Nuclear Waste Policy Act of 1982, contains no clear provision for utility refunds in that case

  18. 2012 nuclear power world report; Kernenergie Weltreport 2012

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2013-06-15

    At the end of 2012, 437 nuclear power plants were available for energy supply in 31 countries of the world. This means that the number was unchanged compared to the previous year's number on 31 December 2011. The aggregate gross power of the plants amounted to approx. 392,793 MWe, the aggregate net power, to 372,572 MWe. This indicates a slight increase of gross and net capacity (gross: 389,367 MWe, net: 369,371 MWe) Two units were commissioned in 2012; 1 unit in China and the Republic of Korea each. Two reactors in Canada resumed commercial operation after a long-term shutdown. The units have been layed-up since the mid 1990ies. Four units were shut down permanently in 2012; 2 units in the United Kingdom, and one unit in Canada and Spain each. The shut-downs in the United Kingdom and Canada have been planned on a long-term base. 68 nuclear generating units - 5 more than at the end of 2011 - were under construction in late 2012 in 14 countries with an aggregate gross power of approx. 70,933 MWe and net power of approx. 66,244 MWe. 9 new projects have been started in 2012 in 3 countries (China, United Arab Emirates, USA). Worldwide, some 110 new nuclear power plants are in the concrete project design, planning, and licensing phases; in some of these cases license applications have been submitted or contracts have already been signed. Some 100 further projects are planned. Net electricity generation in nuclear power plants worldwide in 2012 achieved a level of approx. 2,346.16 billion kWh (2011: approx. 2,497.1 billion kWh). The main cause for the lower production have been the permanent shut-downs of almost all nuclear power plants in Japan since the natural disaster on 11 March 2011. Since the first generation of electricity in a nuclear power plant in the EBR-I fast breeder (USA) on December 20, 1951, cumulated net production has reached approx. 67,946 billion kWh, and operating experience has grown to some 15,050 reactor years. (orig.)

  19. Nuclear energy world Report 2012. September 2013 update

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2013-11-15

    At the end of 2012, 437 nuclear power plants were available for energy supply in 31 countries of the world. This means that the number was unchanged compared to the previous year's number on 31 December 2011. The aggregate gross power of the plants amounted to approx. 392,793 MWe, the aggregate net power, to 372,572 MWe. This indicates a slight increase of gross and net capacity (gross: 389,367 MWe, net: 369,371 MWe). Two units were commissioned in 2012; one unit in China and the Republic of Korea each. Two reactors in Canada resumed commercial operation after a long-term shutdown. The units have been layed-up since the mid 1990ies. Four units were shut down permanently in 2012; 2 units in the United Kingdom, and one unit in Canada and Spain each. The shut-downs in the United Kingdom and Canada have been planned on a long-term base. 68 nuclear generating units - 5 more than at the end of 2011 - were under construction in late 2012 in 14 countries with an aggregate gross power of approx. 70,933 MWe and net power of approx. 66,244 MWe. 9 new projects have been started in 2012 in three countries (China, United Arab Emirates, USA). Worldwide, some 110 new nuclear power plants are in the concrete project design, planning, and licensing phases; in some of these cases license applications have been submitted or contracts have already been signed. Some 100 further projects are planned. Net electricity generation in nuclear power plants worldwide in 2012 achieved a level of approx. 2,350.80 billion (109) kWh (2011: approx. 2,497.10 billion kWh). The main cause for the lower production have been the permanent shut-downs of almost all nuclear power plants in Japan since the natural disaster on 11 March 2011. Since the first generation of electricity in a nuclear power plant in the EBR-I fast breeder (USA) on December 20, 1951, cumulated net production has reached approx. 67,950 billion kWh, and operating experience has grown to some 15,050 reactor years. (orig.)

  20. Permanences GAG-EPA

    CERN Document Server

    GAC-EPA

    2015-01-01

    Le GAC organise chaque mois des permanences avec entretiens individuels. La prochaine permanence se tiendra le : Mardi 5 mai de 13 h 30 à 16 h 00 Salle de réunion de l’Association du personnel Les permanences suivantes auront lieu les mardis 2 juin, 1er septembre, 6 octobre, 3 novembre et 1er décembre 2015. Les permanences du Groupement des Anciens sont ouvertes aux bénéficiaires de la Caisse de pensions (y compris les conjoints survivants) et à tous ceux qui approchent de la retraite. Nous invitons vivement ces derniers à s’associer à notre groupement en se procurant, auprès de l’Association du personnel, les documents nécessaires.

  1. Permanent quadrupole magnets

    International Nuclear Information System (INIS)

    Bush, E.D. Jr.

    1976-01-01

    A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. Based on preliminary tests, it was seen that permanent quadrupole magnets can offer a low cost, reliable solution in applications requiring small, fixed-field focusing devices for use in ion or electron-beam transport systems. Permanent magnets do require special considerations in design, fabrication, handling, and service that are different than encountered in conventional quadrupole magnets. If these basic conditions are satisfied, the resulting beam-focusing device would be stable, maintenance free, with virtually an indefinite lifetime

  2. Permanent quadrupole magnets

    International Nuclear Information System (INIS)

    Bush, E.D. Jr.

    1976-01-01

    A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. (author)

  3. Marxism as permanent revolution

    OpenAIRE

    van Ree, E.

    2013-01-01

    This article argues that the 'permanent revolution' represented the dominant element in Karl Marx and Friedrich Engels' political discourse, and that it tended to overrule considerations encapsulated in 'historical materialism'. In Marx and Engels's understanding, permanent revolution did not represent a historical shortcut under exceptional circumstances, but the course revolutions in the modern era would normally take. Marx and Engels traced back the pattern to the sixteenth century. It is ...

  4. Methods for nondestructive assay holdup measurements in shutdown uranium enrichment facilities

    International Nuclear Information System (INIS)

    Hagenauer, R.C.; Mayer, R.L. II.

    1991-09-01

    Measurement surveys of uranium holdup using nondestructive assay (NDA) techniques are being conducted for shutdown gaseous diffusion facilities at the Oak Ridge K-25 Site (formerly the Oak Ridge Gaseous Diffusion Plant). When in operation, these facilities processed UF 6 with enrichments ranging from 0.2 to 93 wt % 235 U. Following final shutdown of all process facilities, NDA surveys were initiated to provide process holdup data for the planning and implementation of decontamination and decommissioning activities. A three-step process is used to locate and quantify deposits: (1) high-resolution gamma-ray measurements are performed to generally define the relative abundances of radioisotopes present, (2) sizable deposits are identified using gamma-ray scanning methods, and (3) the deposits are quantified using neutron measurement methods. Following initial quantitative measurements, deposit sizes are calculated; high-resolution gamma-ray measurements are then performed on the items containing large deposits. The quantitative estimates for the large deposits are refined on the basis of these measurements. Facility management is using the results of the survey to support a variety of activities including isolation and removal of large deposits; performing health, safety, and environmental analyses; and improving facility nuclear material control and accountability records. 3 refs., 1 tab

  5. Study of the cost-benefit analysis method for safety. Meeting of the Permanent Group in charge of nuclear reactors on the 5 July 2007

    International Nuclear Information System (INIS)

    2007-07-01

    After a recall of the history of the issue of third decennial visit of the 900 MW reactors, of the IRSN preliminary analysis, of elements given to the Permanent Group, of requests made by the ASN, and a presentation of the analysis performed by the IRSN, this large report presents the cost-benefit analysis method and its potential applications (principle, cost assessment, safety assessment, examples) and reports international experience gained in this area: the risk-informed approach (within the IAEA, in the USA, France and other European countries, the specific cost-benefit approach), existing cost-benefit type methods (comparison between methods used in the USA, in France and in Canada), and monetary assessment of accidents. It reports the application of the cost-benefit method for safety and its limitations, and then its application to modifications which have been implemented after safety re-examinations. It discusses the use of level 1 and 2 safety probabilistic studies, and reports the use of a cost-benefit method for safety within the frame of safety re-examinations

  6. 77 FR 73968 - Reconsideration of Certain New Source and Startup/Shutdown Issues: National Emission Standards...

    Science.gov (United States)

    2012-12-12

    ...; FRL-9762-1] RIN 2060-AR62 Reconsideration of Certain New Source and Startup/Shutdown Issues: National... Source and Startup/Shutdown Issues: National Emission Standards for Hazardous Air Pollutants from Coal... November 30, 2012, proposed ``Reconsideration of Certain New Source and Startup/Shutdown Issues: National...

  7. Shutdown cooling temperature perturbation test for analysis of potential flow blockages

    International Nuclear Information System (INIS)

    Handbury, J.; Newman, C.; Shynot, T.

    1996-01-01

    This paper details the methods and results of the 'shutdown cooling test' in October 1995. This novel test was conducted at PLGS while the reactor was shutdown and shutdown cooling (SDC) waster was recirculating to find potential channel blockages resulting from the introduction of wood debris. This test discovered most of the channels that contained major wood and metal debris. (author)

  8. Opinion of the IRSN on serviceability of the 900 MWe reactor vessel - Answers to demands of the Nuclear Permanent Department of December 2005 - Mechanical aspect

    International Nuclear Information System (INIS)

    2010-05-01

    As three demands had been made to EDF in December 2005 regarding the serviceability and more particularly the mechanical behaviour of the 900 MWe reactor vessels, this report discusses the evolution brought to models and proposed by EDF to correct the defect plasticity and take residual stresses into account. This discussion notably concerns the defect height and length range, and the admissible residual stress, but also the use of safety coefficients, transient application, fluence and the brittle-ductile transition temperature. This report from the French Nuclear Safety and Radioprotection Institute (IRSN) outlines the failure risks associated to the vessel in some specific nuclear power stations. Recommendations are made regarding the residual stress amplitude, the risk of fracture by cleavage, and actions to correct fracture risk margins on vessels which do not comply with regulatory criteria

  9. Radiologic states of the WWR-S Bucharest Reactor following definitive shutdown

    International Nuclear Information System (INIS)

    Garlea, C.; Kelerman, C.; Mocioiu, D.; Garlea, I.

    2001-01-01

    The definitive shutdown of a reactor raises problems related to the management of the radioactive inventory. To define the radioactive inventory contained in the burned nuclear fuel and in the neutron activated structural materials computation methods are to be used. Besides the radioactive inventory contained in the main block of the reactor, the one due to the primary circuit contaminated mainly with fission products and corrosion products activated in the reactor core, transported and deposed on the components of the cooling primary circuit should be added. Also another component of the radioactive inventory intervenes, namely, the one due to the contamination of the technological rooms used for various operations the nuclear activities (hot cells, pump room, reactor hall, passage ways to the hot cells and for radioactive source, radioisotope and radioactive waste transport). The activities which made used of the neutron and gamma fluxes for radioisotope production, materials irradiation, research, component testing, resulted in radioactive waste, technological or accidental contaminations of the technological rooms of the reactor. Inspections and current repair interventions resulted also in radioactive waste an contaminations. Consequently systematic measurements with qualified equipment dedicated to alpha, beta, gamma contamination measurements as well as to dose rates determinations for the personnel exposed are necessary. Irrespective of the duration of the reactor conservation or shutdown, the radiologic monitoring should continue. This work presents the results obtained by the research group 'Restoration of Nuclear Sites', working with the IFIN-HH, regarding both the radioactive inventory calculation and measurements of contamination of technological rooms and environment in the reactor vicinity

  10. Demonstration of a transportable storage system for spent nuclear fuel

    International Nuclear Information System (INIS)

    Shetler, J.R.; Miller, K.R.; Jones, R.E.

    1993-01-01

    The purpose of this paper is to discuss the joint demonstration project between the Sacramento Municipal Utility District (SMUD) and the US Department of Energy (DOE) regarding the use of a transportable storage system for the long-term storage and subsequent transport of spent nuclear fuel. SMUD's Rancho Seco nuclear generating station was shut down permanently in June 1989. After the shutdown, SMUD began planning the decommissioning process, including the disposition of the spent nuclear fuel. Concurrently, Congress had directed the Secretary of Energy to develop a plan for the use of dual-purpose casks. Licensing and demonstrating a dual-purpose cask, or transportable storage system, would be a step toward achieving Congress's goal of demonstrating a technology that can be used to minimize the handling of spent nuclear fuel from the time the fuel is permanently removed from the reactor through to its ultimate disposal at a DOE facility. For SMUD, using a transportable storage system at the Rancho Seco Independent Spent-Fuel Storage Installation supports the goal of abandoning Rancho Seco's spent-fuel pool as decommissioning proceeds

  11. Decommissioning of nuclear facilities: 'it can and has been done'

    International Nuclear Information System (INIS)

    2009-01-01

    Considerable international experience gained over the last 20 years demonstrates that nuclear facilities can be safely dismantled and decommissioned once a decision is made to cease operations and permanently shut them down. The term decommissioning is used to describe all the management and technical actions associated with ceasing operation of a nuclear installation and its subsequent dismantling to facilitate its removal from regulatory control (de-licensing). These actions involve decontamination of structures and components, dismantling of components and demolition of buildings, remediation of any contaminated ground and removal of the resulting waste. Worldwide, of the more than 560 commercial nuclear power plants that are or have been in operation, about 120 plants have been permanently shut down and are at some stage of decommissioning. About 10% of all shutdown plants have been fully decommissioned, including eight reactors of more than 100 MWe. A larger number of various types of fuel cycle and research facilities have also been shut down and decommissioned, including: facilities for the extraction and enrichment of uranium, facilities for fuel fabrication and reprocessing, laboratories, isotope production facilities and particle accelerators. This brochure looks at decommissioning across a spectrum of nuclear facilities and shows worldwide examples of successful projects. Further information can be found in NEA publications and on a number of web-sites

  12. On the startup and shutdown of a tandem mirror reactor

    International Nuclear Information System (INIS)

    Chang, F.R.; DeCanio, F.T.; Fisher, J.L.; Madden, P.A.

    1979-01-01

    The startup and shutdown of a fusion reactor must be performed in such a way that the plasma remains MHD stable. In a tandem mirror the stability depends on a sufficiently high pressure ratio between the plugs and the central cell, of the order of 100. Control of the neutral beam input to the plugs by means of active feedback has been investigated to achieve an acceptable pressure ratio throughout the entire startup/shutdown transient. An algorithm to control the beam input power has been developed. The control law was subsequently tested in a tandem mirror simulation code. This paper describes the basic models incorporated in the simulation, as well as the derivation of the control algorithm. The simulation results are presented and the practicality of implementing the algorithm is discussed. 4 refs

  13. Transient fission-product release during reactor shutdown and startup

    International Nuclear Information System (INIS)

    Hunt, C.E.L.; Lewis, B.J.; Dickson, L.W.

    1997-12-01

    Sweep-gas experiments performed at AECL's Chalk River Laboratories from 1979 to 1985 have been further analysed to determine the fraction of the gaseous fission-product inventory that is released on reactor shutdown and startup. Empirical equations were derived and applied to calculate the stable xenon release from companion fuel elements and from a well-documented experimental fuel bundle irradiated in the NRU reactor. The calculated gas release could be matched to the measured values within about a factor of two for an experimental irradiation with a burnup of 217 MWh/kgU. There was also limited information on the fraction of the radioactive iodine that was exposed, but not released, on reactor shutdown. An empirical equation is proposed for calculating this fraction. (author)

  14. The shutdown reactor: Optimizing spent fuel storage cost

    International Nuclear Information System (INIS)

    Pennington, C.W.

    1995-01-01

    Several studies have indicated that the most prudent way to store fuel at a shutdown reactor site safely and economically is through the use of a dry storage facility licensed under 10CFR72. While such storage is certainly safe, is it true that the dry ISFSI represents the safest and most economical approach for the utility? While no one is really able to answer that question definitely, as yet, Holtec has studied this issue for some time and believes that both an economic and safety case can be made for an optimization strategy that calls for the use of both wet and dry ISFSI storage of spent fuel at some plants. For the sake of brevity, this paper summarizes some of Holtec's findings with respect to the economics of maintaining some fuel in wet storage at a shutdown reactor. The safety issue, or more importantly the perception of safety of spent fuel in wet storage, still varies too much with the eye of the beholder, and until a more rigorous presentation of safety analyses can be made in a regulatory setting, it is not practically useful to argue about how many angels can sit on the head of a safety-related pin. Holtec is prepared to present such analyses, but this does not appear to be the proper venue. Thus, this paper simply looks at certain economic elements of a wet ISFSI at a shutdown reactor to make a prima facie case that wet storage has some attractiveness at a shutdown reactor and should not be rejected out of hand. Indeed, an optimization study at certain plants may well show the economic vitality of keeping some fuel in the pool and converting the NRC licensing coverage from 10CFR50 to 10CFR72. If the economics look attractive, then the safety issue may be confronted with a compelling interest

  15. Uncertainty reduction requirements in cores designed for passive reactivity shutdown

    International Nuclear Information System (INIS)

    Wade, D.C.

    1988-01-01

    The first purpose of this paper is to describe the changed focus of neutronics accuracy requirements existing in the current US advanced LMR development program where passive shutdown is a major design goal. The second purpose is to provide the background and rationale which supports the selection of a formal data fitting methodology as the means for the application of critical experiment measurements to meet these accuracy needs. 6 refs., 1 fig., 2 tabs

  16. Passive shut-down of ITER plasma by Be evaporation

    International Nuclear Information System (INIS)

    Amano, Tsuneo.

    1996-02-01

    In an accident event where the cooling system of first wall of the ITER fails, the first wall temperature continues to rise as long as the ignited state of the core plasma persists. In this paper, a passive shut-down scheme of the ITER from this accident by evaporated Be from the first wall is examined. It is shown the estimated Be influx 5 10 24 /sec is sufficient to quench the ignition. (author)

  17. Primary circuit water chemistry during shutdown period at Kalinin NPP

    International Nuclear Information System (INIS)

    Gorbatenko, S.; Otchenashev, G.; Yurmanov, V.

    2005-01-01

    The primary circuit water chemistry feature at Kalinin NPP is using of special up-dated regime during the period of unit shutdown for refueling. The main objective of up-dated regime is removing from the circuit long time living corrosion products on SVO-2 ion exchange filters with the purpose of dose rates reduction from the equipment and in such a way reduction of maintenance personnel overexposure. (N.T.)

  18. Communication received from the Permanent Mission of Denmark to the Agency regarding Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2007-01-01

    The Director General of the International Atomic Energy Agency has received Notes Verbales, dated 1 December 2005, from the Resident Representatives to the Agency of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Czech Republic, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, New Zealand, Poland, Portugal, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, relating to the export of nuclear material, equipment and technology

  19. Communication received from the Permanent Mission of Denmark to the Agency regarding Guidelines for the Export of Nuclear Material, Equipment and Technology

    International Nuclear Information System (INIS)

    2007-01-01

    The Director General of the International Atomic Energy Agency has received Notes Verbales, dated 1 December 2005, from the Resident Representatives to the Agency of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Czech Republic, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, New Zealand, Poland, Portugal, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, relating to the export of nuclear material, equipment and technology [es

  20. Probabilistic analysis of 900 MWe PWR. Shutdown technical specifications

    International Nuclear Information System (INIS)

    Mattei, J.M.; Bars, G.

    1987-11-01

    During annual shutdown, preventive maintenance and modifications which are made on PWRs cause scheduled unavailabilities of equipment or systems which might harm the safety of the installation, in spite of the low level of decay heat during this period. The pumps in the auxiliary feedwater system, component cooling water system, service water system, the water injection arrays (LPIS, HPIS, CVCS), and the containment spray system may have scheduled unavailability, as well as the power supply of the electricity boards. The EDF utility is aware of the risks related to these situations for which accident procedures have been set up and hence has proposed limiting downtime for this equipment during the shutdown period, through technical specifications. The project defines the equipment required to ensure the functions important for safety during the various shutdown phases (criticality, water inventory, evacuation of decay heat, containment). In order to be able to judge the acceptability of these specifications, the IPSN, the technical support of the Service Central de Surete des Installations Nucleaires, has used probabilistic methodology to analyse the impact on the core melt probability of these specifications, for a French 900 MWe PWR

  1. Evaluation of the safety margins during shutdown for NPP Krsko

    International Nuclear Information System (INIS)

    Bencik, V.; Sadek, S.; Bajs, T.

    2004-01-01

    In the paper the results of RELAP5/mod3.3 calculations of critical parameters during shutdown for NPP Krsko are presented. Conservative evaluations have been performed at NPP Krsko to determine the minimum configuration of systems required for the safe shutdown operation. Critical parameters in these evaluations are defined as the time to start of the boiling and the time of the core dry-out. In order to have better insight into the available margins, the best estimate code RELAP5/mod3.3 has been used to calculate the same parameters. The analyzed transient is the loss of the Residual Heat Removal (RHR) system, which is used to remove decay heat during shutdown conditions. Several configurations that include open and closed Reactor Coolant System (RCS) were considered in the evaluation. The RELAP5/mod3.3 analysis of the loss of the RHR system has been performed for the following cases: 1) RCS closed and water solid, 2) RCS closed and partially drained, 3) Pressurizer manway open, Steam Generator (SG) U tubes partially drained, 4) Pressurizer and SG manways open, SG U tubes completely drained, 5) Pressurizer manway open, SGs drained, SG nozzle dams installed and 6) SG nozzle dams installed, pressurizer manway open, 1 inch break at RHR pump discharge in the loop with pressurizer. Both RHR trains were assumed in operation prior to start of the transient. The maximum average steady state temperature for all analyzed cases was limited to 333 K. (author)

  2. Nuclear analysis for ITER

    International Nuclear Information System (INIS)

    Santoro, R.T.; Iida, H.; Khripunov, V.; Petrizzi, L.; Sato, S.; Sawan, M.; Shatalov, G.; Schipakin, O.

    2001-01-01

    This paper summarizes the main results of nuclear analysis calculations performed during the International Thermonuclear Experimental Reactor (ITER) Engineering Design Activity (EDA). Major efforts were devoted to fulfilling the General Design Requirements to minimize the nuclear heating rate in the superconducting magnets and ensuring that radiation conditions at the cryostat are suitable for hands-on-maintenance after reactor shut-down. (author)

  3. Risk contribution from low power and shutdown of a pressurized water reactor

    International Nuclear Information System (INIS)

    Chu, T.L.; Pratt, W.T.

    1997-01-01

    During 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. Two plants, Surry (a pressurized water reactor) and Grand Gulf (a boiling water reactor), were selected for study by Brookhaven National Laboratory and Sandia National Laboratories, respectively. The program objectives included assessing the risks of severe accidents initiated during plant operational states other than full power operation and comparing estimated core damage frequencies, important accident sequences, and other qualitative and quantitative results with full power accidents as assessed in NUREG-1150. The scope included a Level 3 PRA for traditional internal events and a Level 1 PRA on fire, flooding, and seismically induced core damage sequences. 12 refs., 7 tabs

  4. Selection of equipment for safe shutdown in the event of earthquake

    International Nuclear Information System (INIS)

    Romano Gomez, J.; Perez Alcaniz, T.; Esteban Barriendos, M.

    1993-01-01

    This paper presents the work carried out at the Almaraz Nuclear Power Plant for selecting equipment that contributes to reactor safe shutdown in the event of earthquake. The objective was to comply with the requirements defined by the US NRC in Generic Letter 87-02, 'Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors'. The analysis framework and the method applied followed the generic procedures prepared by the Seismic Qualification Utility Group of which Almaraz NPP is a member, along with other Spanish power plants. The equipment selected shall be subjected to the Application Programme of the above-mentioned Generic Letter. The aim has been to cover the objectives of the programme and, at the same time, to ensure compatibility with plant operating procedures. (author)

  5. Questions and answers about the reactor shutdown at the Barsebaeck plant

    International Nuclear Information System (INIS)

    1992-01-01

    At a scram at the Barsebaeck 2 reactor on July 28 1992, a safety valve open unintentionally, and steam was released from the reactor vessel into the containment. The emergency spray system started sprinkling the vessel (the core spray system was also active for a short while). After one hour, the sprinkling was interupted, and at about the same time it was found that the steam jet had tore off insulation material (from the containment walls) which started to clog the sieves for the emergency sprinkling water, disturbing the pumping. The clogging appeared much more rapidly than expected (1 h in stead of 10 h). Five Swedish reactors for similar design have been shutdown pending a reconstruction of the emergency spray feed system. This pamphlet is directed to the general public, explaining the problems and commenting on nuclear safety issues

  6. Monitoring the risk of loss of heat sink during plant shutdowns at Bruce Generating Station 'A'

    International Nuclear Information System (INIS)

    Krishnan, K.S.; Mancuso, F.; Vecchiarelli, D.

    1996-01-01

    A relatively simple loss of shutdown heat sink fault tree model has been developed and used during unit outages at Bruce Nuclear Generation Station 'A' to assess, from a risk and reliability perspective, alternative heat sink strategies and to aid in decisions on allowable outage configurations. The model is adjusted to reflect the various unit configurations planned during a specific outage, and identifies events and event combinations leading to loss of fuel cooling. The calculated failure frequencies are compared to the limits consistent with corporate and international public safety goals. The importance measures generated by the interrogation of the fault tree model for each outage configuration are also used to reschedule configurations with high fuel damage frequency later into the outage and to control the configurations with relatively high probability of fuel damage to short intervals at the most appropriate time into the outage. (author)

  7. The Chernobyl plant shutdown; L'arret de la centrale de Tchernobyl

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    The Chernobylsk-1 reactor, operational in september 1977 has been stopped in november 1996; the Chernobylsk-2 reactor started in november 1978 is out of order since 1991 following a fire. The Chernobylsk-3 reactor began in 1981. During the last three years it occurs several maintenance operations that stop it. In june 2000, the Ukrainian authorities decided to stop it definitively on the 15. of december (2000). This file handles the subject. it is divided in four chapters: the first one gives the general context of the plant shutdown, the second chapter studies the supporting projects to stop definitively the nuclear plant, the third chapter treats the question of the sarcophagus, and the fourth and final chapter studies the consequences of the accident and the contaminated territories. (N.C.)

  8. Extending reactor time-to-poison and reducing poison shutdown time by pre-shutdown power alterations

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, Edward

    1963-10-15

    Manipulation of reactor power prior to shutdown and increasing the time- to-poison a sufficient amount to enable the required maintenance work to be completed and the reactor immediately restarted are discussed. The method employed in the NRU Reactor to gain the maximum timeto-poison with the least production loss is outlined. The method is based on intuition and is described by means of an analog of the iodine--xenon equations rather than the equations themselves. (C.E.S.)

  9. Kinetic analyses on startup and shutdown chemistry of BWR plant

    International Nuclear Information System (INIS)

    Domae, Masafumi; Fujiwara, Kazutoshi; Inagaki, Hiromitsu

    2012-09-01

    During startup and shutdown of Boiling Water Reactor (BWR) plants, temperature and dissolved oxygen (DO) concentration of reactor water change in a wide range. The changes result in variation of conductivity and pH of the reactor water. It has been speculated that the water chemistry change is due to dissolution of the oxides on fuel claddings and structural materials. However, detailed mechanism is not known. In the present paper, trend of recent water chemistry in several BWR plants during startup and shutdown is presented. Conductivity and pH are convenient indication of coolant purity. We tried to clarify the mechanism of the change in the conductivity and the pH value during startup and shutdown, based on the water chemistry data measured. In the water chemistry data, change in chromate concentration and Ni 2+ concentration is rather large. It is assumed that change in the chromate concentration and the Ni 2+ concentration results in the time variation of the conductivity and the pH value. It is reasonable to consider that the increase in the chromate concentration and the Ni 2+ concentration is ascribed to dissolution of Cr oxides and Ni oxides, respectively. A model of dissolution of the Cr oxides and the Ni oxides is proposed. A concept of finite inventory of the Cr oxides and the Ni oxides in the coolant system is introduced. The model is as follows. Chromate is generated by oxidation of the Cr oxides and the Cr dissolution rate depends on the DO concentration. The dissolution rate of chromate is in proportion to DO concentration, the inventory of Cr and difference between solubility limit and the chromate concentration. On the other hand, Ni 2+ is formed by dissolution of the Ni oxides, and DO is not necessary in this process. The dissolution rate of Ni 2+ is in proportion to the inventory of Ni and difference between solubility limit and the Ni 2+ concentration. Coolant is continuously purified, and the chromate concentration and the Ni 2+ concentration

  10. Introduction to permanent magnets

    International Nuclear Information System (INIS)

    Zijlstra, H.

    1985-01-01

    Some general considerations concerning the application of permanent magnets are developed. The relevant magnet properties are discussed, with particular reference to Nd-Fe-B alloy. The author comes to the following conclusions; the air gap field B should be high, for high electrical efficiency; the magnet should face the air gap, for efficient use of the magnet material; the magnet material should therefore have a high remanence; and the new Nd-Fe-B magnet fits in nicely, having (potentially) the highest remanence ever reported in permanent magnets, combined with sufficient coercivity to sustain it

  11. Work Breakdown Structure and Work Packages for Decommissioning the Nuclear Research Reactor VVR-S Magurele-Bucharest

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-06-15

    The research reactor type VVR-S (tank type, water cooled, moderator and reflector, thermal power 2 MW, thermal energy 9.52 GWd) was put into service in July 1957, and in December 1997, was shut down. In 2002, the Romanian Government decided to put the research reactor into a permanent shutdown condition in order to start decommissioning. This nuclear facility had been used in nuclear research and radioisotope production for 40 years without any events, incidents or accidents. At the same site, in the immediate vicinity of the research reactor, there are many other nuclear facilities: a radioactive waste treatment plant, a tandem Van de Graaff heavy ion accelerator, a cyclotron, an industrial irradiator and a radioisotope production centre.

  12. 2010 nuclear power world report

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    At the end of 2010, 443 nuclear power plants were available for energy supply in 30 countries of the world. This are 6 plants more than at the end of 2009. The aggregate gross power of the plants amounted to approx. 396,118 MWe, the aggregate net power, to 375,947 MWe. This capacity numbers are a little bit more than one year before (gross: 391,551 MWe, net: 371,331 MWe). Six unites were commissioned in 2010; 2 units in China and India each and one unit in the Republic of Korea and Russia each. One unit, the Fast Breeder Pilot Reactor Monju in Japan, was connected to the grid after a long-term shutdown. One nuclear power plant, the Prototype Fast Breeder Reactor Phenix in France, was shut down permanently in 2010. 62 nuclear generating units, i.e. 9 plants more than at the end of 2009, were under construction in late 2010 in 15 countries with an aggregate gross power of approx. 63,998 MWe. Worldwide, some 90 new nuclear power plants are in the concrete project design, planning, and licensing phases; in some of these cases license applications have been submitted or contracts have already been signed. Some 120 further projects are planned. Net electricity generation in nuclear power plants worldwide in 2010 achieved another reasonable ranking level of approx. 2,627.5 billion kWh (2009: approx. 2,558 billion kWh). Since the first generation of electricity in a nuclear power plant in the EBR-I fast breeder (USA) on December 20, 1951, cumulated net production has reached approx. 63,100 billion kWh, and operating experience has grown to some 14,400 reactor years. (orig.)

  13. Object permanence in lemurs.

    Science.gov (United States)

    Deppe, Anja M; Wright, Patricia C; Szelistowski, William A

    2009-03-01

    Object permanence, the ability to mentally represent objects that have disappeared from view, should be advantageous to animals in their interaction with the natural world. The objective of this study was to examine whether lemurs possess object permanence. Thirteen adult subjects representing four species of diurnal lemur (Eulemur fulvus rufus, Eulemur mongoz, Lemur catta and Hapalemur griseus) were presented with seven standard Piagetian visible and invisible object displacement tests, plus one single visible test where the subject had to wait predetermined times before allowed to search, and two invisible tests where each hiding place was made visually unique. In all visible tests lemurs were able to find an object that had been in clear view before being hidden. However, when lemurs were not allowed to search for up to 25-s, performance declined with increasing time-delay. Subjects did not outperform chance on any invisible displacements regardless of whether hiding places were visually uniform or unique, therefore the upper limit of object permanence observed was Stage 5b. Lemur species in this study eat stationary foods and are not subject to stalking predators, thus Stage 5 object permanence is probably sufficient to solve most problems encountered in the wild.

  14. 40 CFR 60.1695 - What happens to the operating requirements during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... requirements during periods of startup, shutdown, and malfunction? 60.1695 Section 60.1695 Protection of... Requirements § 60.1695 What happens to the operating requirements during periods of startup, shutdown, and... municipal waste combustion unit startup, shutdown, or malfunction. (b) Each startup, shutdown, or...

  15. 40 CFR 60.1220 - What happens to the emission limits during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... during periods of startup, shutdown, and malfunction? 60.1220 Section 60.1220 Protection of Environment... Emission Limits § 60.1220 What happens to the emission limits during periods of startup, shutdown, and... waste combustion unit startup, shutdown, or malfunction. (b) Each startup, shutdown, or malfunction must...

  16. 40 CFR 62.15150 - What happens to the operating requirements during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... requirements during periods of startup, shutdown, and malfunction? 62.15150 Section 62.15150 Protection of... § 62.15150 What happens to the operating requirements during periods of startup, shutdown, and... municipal waste combustion unit startup, shutdown, or malfunction. (b) Each startup, shutdown, or...

  17. Calculation of the negative reactivity inserted by the shutdown system number two (SDS2) of a CANDU reactor

    Energy Technology Data Exchange (ETDEWEB)

    Arsenault, B [Ecole Polytechnique, Montreal, PQ (Canada)

    1994-12-31

    The secondary shutdown system (SDS2) of a CANDU reactor consists of liquid poison injection through nozzles disposed horizontally across the core. The nominal concentration of gadolinium nitrate poison is 8000 ppm. With the methods available to the nuclear industry for calculating the negative reactivity inserted by the SDS2, some approximations are needed, and a simplified model of poison propagation has to be used to calculate the differential cross sections. The objective of this paper is to evaluate the errors introduced by the approximations in the supercell and core calculations. The MULTICELL and EXCELL codes gave different power distributions, and further work was recommended. 9 refs., 2 tabs., 4 figs.

  18. Reliability analysis of self-actuated shutdown system

    International Nuclear Information System (INIS)

    Itooka, S.; Kumasaka, K.; Okabe, A.; Satoh, K.; Tsukui, Y.

    1991-01-01

    An analytical study was performed for the reliability of a self-actuated shutdown system (SASS) under the unprotected loss of flow (ULOF) event in a typical loop-type liquid metal fast breeder reactor (LMFBR) by the use of the response surface Monte Carlo analysis method. Dominant parameters for the SASS, such as Curie point characteristics, subassembly outlet coolant temperature, electromagnetic surface condition, etc., were selected and their probability density functions (PDFs) were determined by the design study information and experimental data. To get the response surface function (RSF) for the maximum coolant temperature, transient analyses of ULOF were performed by utilizing the experimental design method in the determination of analytical cases. Then, the RSF was derived by the multi-variable regression analysis. The unreliability of the SASS was evaluated as a probability that the maximum coolant temperature exceeded an acceptable level, employing the Monte Carlo calculation using the above PDFs and RSF. In this study, sensitivities to the dominant parameter were compared. The dispersion of subassembly outlet coolant temperature near the SASS-was found to be one of the most sensitive parameters. Fault tree analysis was performed using this value for the SASS in order to evaluate the shutdown system reliability. As a result of this study, the effectiveness of the SASS on the reliability improvement in the LMFBR shutdown system was analytically confirmed. This study has been performed as a part of joint research and development projects for DFBR under the sponsorship of the nine Japanese electric power companies, Electric Power Development Company and the Japan Atomic Power Company. (author)

  19. Safe shutdown analysis for submerged equipment inside containment

    International Nuclear Information System (INIS)

    Song, Dong Soo; Lee, Seung Chan; Yoon, Duk Joo; Ha, Sang Jun

    2017-01-01

    The purpose of the paper is to analyze internal flooding effects on the submerged safety-related components inside containment building. Safe shutdown analysis has been performed based on the criteria, assumptions and guideline provided in ANSI/ANS-56.11-1988 and ANSI/ANS-58.11-1988. Flooding can be postulated from a failure of several systems located inside the containment. Loss of coolant accident (LOCA), Feed water line break (FWLB), and other pipe breaks/cracks are assumed. The worst case flooding scenario is a large break LOCA. The maximum flood level for a large break LOCA is calculated based on the combined inventory of the reactor coolant system, the three accumulators, the boron injection tank (BIT), the chemical additive tank (CAT), and the refueling water storage tank (RWST) flooding the containment. The maximum flood level that could occur from all of the water which is available in containment is 2.3 m from the base elevation. A detailed flooding analysis for the components has been performed to demonstrate that internal flooding resulting from a postulated initiating event does not cause the loss of equipment required to achieve and maintain safe shutdown of the plant, emergency core cooling capability, or equipment whose failure could result in unacceptable offsite radiological consequences. The flood height can be calculated as h = (dh/dt) x (t-t 0 ) + h 0 , where h = time dependent flood height and subscript 0 means the initial value and height slope dh/dt. In summary, the submerged components inside containment are acceptable because they complete the mission of safety injection (SI) prior to submeregency or have no safe shutdown function including containment isolation during an accident. (author)

  20. Long-term problem for the nuclear industry

    International Nuclear Information System (INIS)

    Norman, C.

    1982-01-01

    Dismantling of the 24-year-old Shippingport atomic power station over the next two years will test whether the nuclear industry can safely dispose of high-level radioactive facilities. Recent findings that some components will remain radioactive longer than anticipated may require dismantling instead of the permanent entombment the industry was planning. The five-year dismantlement will cost $40 million and generate 11,700 cubic meters of radioactive waste. Larger reactors will be even more costly. Current regulations require utilities to choose between dismantlement, safe storage, or entombment of contaminated materials. Each has its problems, but the industry objects to an evolving policy for dismantling and an accompanying requirement for a segregated decommissioning fund that would be set aside before a reactor begins operating or during plant lifetime. The latter would require an adequate insurance mechanism to cover premature shutdown

  1. Approach and results of the PWR low power and shutdown accident frequencies program - Coarse screening analysis for Surry

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Luckas, W.; Wong, S.M.; Fitzpatrick, R.G.

    1991-01-01

    Traditionally, probabilistic risk analyses of severe accidents in nuclear power plants have limited themselves to consideration of the set of initiating events occurring during full power operation. However, some analyses of accident initiators during low power, shutdown, and other modes of plant operation other than full power have been performed. These studies as well as the Chernobyl accident and recent operating experience at US pressurized water reactors (PWRs) suggested that risks during low power and shutdown could be significant. As such, the analysis of the frequencies, consequences, and risks of these accidents was identified as one task in the Nuclear Regulatory Commission staff's study of the implications of the Chernobyl accident to US commercial nuclear power plants. This program is an ongoing high priority effort at Brookhaven National Laboratory (BNL). The scope includes a Level 1 probabilistic risk assessment (PRA) with internal fire and flood for Surry Unit 1 (PWR). This program is also closely coupled to a parallel project for the Grand Gulf plant (BWWR) being conducted by SNL. The program is being performed in two phases. Phase 1 represents a coarse screening analysis to identify dominant accident scenarios as well as risk dominant plant configurations and plant operating states. In Phase 2, a detailed PRA will be performed for the dominant accident scenarios/operating states identified in Phase 1. The objectives, results and insights of Phase 1 are discussed in the paper

  2. Evaluation of power behavior during startup and shutdown procedures of the IPR-R1 Triga Reactor

    International Nuclear Information System (INIS)

    Zangirolami, Dante M.; Mesquita, Amir Z.; Ferreira, Andrea V.

    2009-01-01

    The IPR-R1 nuclear reactor of Centro de Desenvolvimento da Tecnologia Nuclear - CDTN/CNEN is a TRIGA Mark I pool type reactor cooled by natural circulation of light water. In the IPR-R1, the power is measured by four nuclear channels, neutron-sensitive chambers, which are mounted around the reactor core: the Startup Channel for power indication during reactor startup; the Logarithmic Wide Range Power Monitoring Channel; the Linear Multi-Range Power Monitoring Channel and the Percent Power Safety Channel. A data acquisition system automatically does the monitoring and storage of all the reactor operational parameters including the reactor power. The startup procedure is manual and the time to reach the desired reactor power level is different on each irradiation which may introduces differences in induced activity of samples irradiated in different irradiations. In this work, the power evolution during startup and shutdown periods of IPR-R1 operation was evaluated and the mean values of reactor energy production in these operational phases were obtained. The analyses were performed on basis of the Linear Multi-Range Channel data. The results show that the sum of startup and shutdown periods corresponds to 1% of released energy for irradiations during 1h at 100kW. This value may be useful to correct experimental data in neutron activation experiments. (author)

  3. Transient fission product release during reactor shutdown and startup

    International Nuclear Information System (INIS)

    Hunt, C.E.L.; Lewis, B.J.

    1995-01-01

    Sweep gas experiments performed at CRL from 1979 to 1985 have been analysed to determine the fraction of the fission product gas inventory that is released on reactor shutdown and startup. Empirical equations were derived and applied to calculate the xenon release from companion fuel elements and from a well documented experimental fuel bundle irradiated in the NRU reactor. The measured gas release could be matched to within about a factor of two for an experimental irradiation with a burnup of 217 MWh/kgU. (author)

  4. Shutdown channels and fitted interlocks in atomic reactors

    International Nuclear Information System (INIS)

    Furet, J.; Landauer, C.

    1968-01-01

    This catalogue consists of tables (one per reactor) giving the following information: number and type of detectors, range of the shutdown channels, nature of the associated electronics, thresholds setting off the alarms, fitted interlocks. These cards have been drawn up with a view to an examination of the reactors safety by the 'Reactor Safety Sub-Commission', they take into account the latest decisions. The reactors involved in this review are: Azur, Cabri, Castor-Pollux, Cesar-Marius-2, Edf-2, EL3, EL4, Eole, G1, G2-G3, Harmonie, Isis, Masurca, Melusine, Minerve, Osiris, Pegase, Peggy, PAT, Rapsodie, SENA, Siloe, Siloette, Triton-Nereide, and Ulysse. (authors) [fr

  5. Modelling of liquid injection shutdown system (LISS) in ACR-1000

    International Nuclear Information System (INIS)

    Boubcher, M.; Colton, A.; Donnelly, J.V.

    2008-01-01

    Modelling of the Liquid Injection Shutdown System (LISS) in the ACR-1000 reactor core must account for the major phenomena that occur following its activation, namely the moderator hydraulics and core neutronics. The former requires modelling of the poison volumes, their time of entry into the reactor, and their propagation into the moderator after emission from the nozzle. The latter requires the reactivity worth of varying volumes and geometries of poisoned moderator fluid in order to simulate the reactivity effect of the injected poison. The time-dependent poison map is generated from hydraulic calculations, and then the neutronics data for standard geometries and concentrations is constructed using DRAGON. (author)

  6. Reliability modeling of Clinch River breeder reactor electrical shutdown systems

    International Nuclear Information System (INIS)

    Schatz, R.A.; Duetsch, K.L.

    1974-01-01

    The initial simulation of the probabilistic properties of the Clinch River Breeder Reactor Plant (CRBRP) electrical shutdown systems is described. A model of the reliability (and availability) of the systems is presented utilizing Success State and continuous-time, discrete state Markov modeling techniques as significant elements of an overall reliability assessment process capable of demonstrating the achievement of program goals. This model is examined for its sensitivity to safe/unsafe failure rates, sybsystem redundant configurations, test and repair intervals, monitoring by reactor operators; and the control exercised over system reliability by design modifications and the selection of system operating characteristics. (U.S.)

  7. Quality assurance program plan fuel supply shutdown project

    International Nuclear Information System (INIS)

    Metcalf, I.L.

    1998-01-01

    This Quality Assurance Program plan (QAPP) describes how the Fuel Supply Shutdown (FSS) project organization implements the quality assurance requirements of HNF-MP-599, Project Hanford Quality Assurance Program Description (QAPD) and the B and W Hanford Company Quality Assurance Program Plan (QAPP), FSP-MP-004. The QAPP applies to facility structures, systems, and components and to activities (e.g., design, procurement, testing, operations, maintenance, etc.) that could affect structures, systems, and components. This QAPP also provides a roadmap of applicable Project Hanford Policies and Procedures (PHPP) which may be utilized by the FSS project organization to implement the requirements of this QAPP

  8. The Question of Decalage Between Object Permanence and Person Permanence

    Science.gov (United States)

    And Others; Jackson, Elaine

    1978-01-01

    Presents a study of decalage between object permanence and person permanence. Decalage was influenced by environmental as well as stimulus factors with infants tested between 6- and 81/4-months/of-age. (BD)

  9. Is Slovakia prepared for nuclear power boom?

    International Nuclear Information System (INIS)

    Mikus, T.

    2009-01-01

    In this lecture the statistical data about number of reactors in operation worldwide, nuclear share in electricity generation in 2008, number of reactors by age and shutdown reactors by country are reviewed. Current Slovak national situation is discussed.

  10. Variable Permanent Magnet Quadrupole

    International Nuclear Information System (INIS)

    Mihara, T.; Iwashita, Y.; Kyoto U.; Kumada, M.; NIRS, Chiba; Spencer, C.M.; SLAC

    2007-01-01

    A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments

  11. Experience gained during commissioning and trial operation of Mochovce Nuclear Power Plant

    International Nuclear Information System (INIS)

    GaL, P.; Adamica, T.; Marosik, V.; Rehak, A.

    2000-01-01

    In this paper authors describe the experience gained during commissioning and trial operation of Mochovce NPP (EMO). The first year of EMO operation from the point of view of safety and reliability was successful. Evidently we were challenged with certain problems characteristic to this stage of operation which resulted in automatic reactor shutdown. There were 11 automatic shutdowns in 1998 by action of the quick emergency protection AO-1 and two manual shutdowns by the AO-1 key. In 1999, there were 6 automatic shutdowns by action of the quick emergency protection AO-1. Three of them was connected to the falsely activated binary signal of MCP switch of, in two cases the reason came out from the turbo-generator (TG) cooling water system. Very positive trend in the operation of both units shows the fact that during all commissioning period of the second unit there were only three automatic reactor shutdowns by the signal AO-1. All these actions were done in frame of commissioning tests. All causes which activated the automatic unit shutdowns were found out and rectified, the overall tuning of the cooling water system is on the process now. The solution of this problem is possible only power commissioning, and in the stage of the trial operation had no direct impacts on the nuclear, radiation, or technical safety respectively. In 1998 two events according to the INES scale after second unit commissioning because of two unit links of the cooling water system. The operational events during the commissioning tests, start-up tests, physical commissioning, were ranked the category 1 ('Action of SIS U040 p po <8,34 MPa at the system 2 and 3' and 'Breaching the L and C'). In 1999 only events occurred that were ranked in the category safety insignificant events and lower (category 0, or off the scale respectively). In the frame of the safety culture principles adopted, such as critical attitude, exact and careful approach, and communication, these problems were given the

  12. Superconducting permanent magnets

    International Nuclear Information System (INIS)

    Wipf, S.L.; Laquer, H.L.

    1989-01-01

    The concept of superconducting permanent magnets with fields trapped in shells or cylinders of Type II superconductors is an old one. Unfortunately, the low values of 0.5 to 1T for the first flux jump field, which is independent of the actual current density, have frustrated its implementation with classical Type II superconductors. The fact that the flux jump fields for high temperature superconductors should be an order of magnitude larger at liquid nitrogen temperatures allows us to reconsider these options. Analysis of the hysteresis patterns, based on the critical state model, shows that, if the dimensions are chosen so that the sample is penetrated at a field B/sub p/, which is equal to or just less than the first flux jump field, B/sub fj/, a temporarily applied field of 2B/sub fj/ will trap 0.5 B/sub fj/. Thus for a 90 K superconductor with a B/sub fj/ of 6T, a permanent field of 3 T should be trapped, with an energy product of 1.8 MJ/m/sup 3/ (225 MG . Oe). This is five times as large as for the best permanent magnet materials. The authors discuss means to verify the analysis and the limitations imposed by the low critical current densities in presently available high temperature superconductors

  13. Global shutdown dose rate maps for a DEMO conceptual design

    International Nuclear Information System (INIS)

    Leichtle, D.; Pereslavtsev, P.; Sanz, J.; Catalan, J.P.; Juarez, R.

    2015-01-01

    Highlights: • Application of R2S-method on high-resolution full torus sector mesh for DEMO. • Absorbed dose rates after shutdown for a variely of RH equipment at typical locations. • Idenification of radiation levels at several port based locations. - Abstract: For the calculations of highly reliable shutdown dose rate (SDR) maps in fusion devices like a DEMO plant, the Rigorous-2-step (R2S) method is nowadays routinely applied using high-resolution decay gamma sources from initial high-resolution neutron flux meshes activating all materials in the system. This approach has been utilized in the present paper with the objective to provide SDR results relevant for RH systems of a conceptual DEMO design developed in the EU. The primary objective was to assess specific locations of interest for RH equipment inside the vessel and along the extension of maintenance ports. To this end, a provisional DEMO MCNP model has been used, featuring HCLL-type blankets, tungsten/copper divertor, manifolds, vacuum vessel with ports and toroidal field coils. The operational scenario assumed 2.1 GW fusion power and a life-time of 20 years with plant availability of 30%, where removable parts will be extracted after 5.2 years. Results of absorbed dose rate distributions for several relevant materials are presented and discussed in terms of the different contributions from the various activated components.

  14. Low Power Shutdown PSA for CANDU Type Plants

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Yeon Kyoung; Kim, Myung Su [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    KHNP also have concentrated on full power PSA. Some recently constructed OPR1000 type plants and APR1400 type plants have performed the low power and shutdown (LPSD) PSA. The purpose of LPSD PSA is to identify the main contributors on the accident sequences of core damage and to find the measure of safety improvement. After the Fukushima accident, Korean regulatory agency required the shutdown severe accident management guidelines (SSAMG) development for safety enhancement. For the reliability of SSAMG, KHNP should develop the LPSD PSA. Especially, the LPSD PSA for CANDU type plant had developed for the first time in Korea. This paper illustrates how the LPSD PSA for CANDU type developed and the core damage frequency (CDF) is different with that of full power PSA. KHNP performed LPSD PSA to develop the SSAMG after the Fukushima accidents. The results show that risk at the specific operation mode during outage is higher than that of full power operation. Also, the results indicated that recovery failure of class 4 power at the POS 5A, 5B contribute dominantly to the total CDF from importances analysis. LPSD PSA results such as CDF with initiating events and POSs, risk results with plant damage state, and containment failure probability and frequency with POSs can be used by inputs for developing the SSAMG.

  15. Design and analysis of shutdown mechanisms of PFBR

    International Nuclear Information System (INIS)

    Vijayashree, R.; Rajan Babu, V.; Puthiyavinayagam, P.; Chellapandi, P.; Chetal, S.C.

    2009-01-01

    Prototype Fast Breeder Reactor (PFBR) is equipped with two independent, fast acting and diverse shutdown systems. The absorber rod of the first system is called Control and Safety Rod (CSR) and that of the second system is called Diverse Safety Rod (DSR). The respective drive mechanisms are called Control and Safety Rod Drive Mechanism (CSRDM) and Diverse Safety Rod Drive Mechanism (DSRDM). The conceptual features of the Absorber Rods (ARs) and Absorber Rod Drive Mechanisms (ARDMs) are given in the figures. The functions and design specifications of the ARDMs are listed. The theoretical results of the performance of the shutdown systems during scram are presented. The design was always backed up with testing and design validation. The individual subassemblies testing and the design have proceeded side by side, the efforts finally culminated into the manufacturing of 1:1 scale prototype ARDMs and ARs. The prototypes were extensively tested in air, water and sodium to qualify them for reactor application. A companion paper in this conference gives the details of design validation by testing. This paper gives a brief account of the design of ARDMs and ARs. (author)

  16. Runaway electron generation during plasma shutdown by killer pellet injection

    International Nuclear Information System (INIS)

    Gal, K; Feher, T; Smith, H; Fueloep, T; Helander, P

    2008-01-01

    Tokamak discharges are sometimes terminated by disruptions that may cause large mechanical and thermal loads on the vessel. To mitigate disruption-induced problems it has been proposed that 'killer' pellets could be injected into the plasma in order to safely terminate the discharge. Killer pellets enhance radiative energy loss and thereby lead to rapid cooling and shutdown of the discharge. But pellets may also cause runaway electron generation, as has been observed in experiments in several tokamaks. In this work, runaway dynamics in connection with deuterium or carbon pellet-induced fast plasma shutdown is considered. A pellet code, which calculates the material deposition and initial cooling caused by the pellet is coupled to a runaway code, which determines the subsequent temperature evolution and runaway generation. In this way, a tool has been created to test the suitability of different pellet injection scenarios for disruption mitigation. If runaway generation is avoided, the resulting current quench times are too long to safely avoid large forces on the vessel due to halo currents

  17. Global shutdown dose rate maps for a DEMO conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    Leichtle, D., E-mail: dieter.leichtle@f4e.europa.eu [Karlsruhe Institute of Technology KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Pereslavtsev, P. [Karlsruhe Institute of Technology KIT, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Sanz, J.; Catalan, J.P.; Juarez, R. [Universidad Nacional de Educación a Distancia(UNED), E.T.S. Ingenieros Industriales, C/ Juan del Rosal 12, 28040 Madrid (Spain)

    2015-10-15

    Highlights: • Application of R2S-method on high-resolution full torus sector mesh for DEMO. • Absorbed dose rates after shutdown for a variely of RH equipment at typical locations. • Idenification of radiation levels at several port based locations. - Abstract: For the calculations of highly reliable shutdown dose rate (SDR) maps in fusion devices like a DEMO plant, the Rigorous-2-step (R2S) method is nowadays routinely applied using high-resolution decay gamma sources from initial high-resolution neutron flux meshes activating all materials in the system. This approach has been utilized in the present paper with the objective to provide SDR results relevant for RH systems of a conceptual DEMO design developed in the EU. The primary objective was to assess specific locations of interest for RH equipment inside the vessel and along the extension of maintenance ports. To this end, a provisional DEMO MCNP model has been used, featuring HCLL-type blankets, tungsten/copper divertor, manifolds, vacuum vessel with ports and toroidal field coils. The operational scenario assumed 2.1 GW fusion power and a life-time of 20 years with plant availability of 30%, where removable parts will be extracted after 5.2 years. Results of absorbed dose rate distributions for several relevant materials are presented and discussed in terms of the different contributions from the various activated components.

  18. Risk contribution from low power, shutdown, and other operational modes beyond full power

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, D.W.; Brown, T.D. [Sandia National Labs., Albuquerque, NM (United States); Chu, T.L. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1995-04-01

    During 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. Two plants, Surry (a pressurized water reactor) and Grand Gulf (a boiling water reactor), were selected for study by Brookhaven National Laboratory and Sandia National Laboratories, respectively. The program objectives included assessing the risks of severe accidents initiated during plant operational states other than full power and comparing estimated core damage frequencies, important accident sequences, and other qualitative and quantitative results with full power accidents as assessed in NUREG-1150. The scope included a Level 3 probabilistic risk assessment (PRA) for traditional internal events and a Level 1 PRA on fire, flooding, and seismically induced core damage sequences. A phased approach was used in Level 1. In Phase 1 the concept of plant operational states (POSs) was developed to provide a better representation of the plant as it transitions from power to nonpower operation. This included a coarse screening analysis of all POSs to identify vulnerable plant configurations, to characterize (on a high, medium, or low basis) potential frequencies of core damage accidents, and to provide a foundation for a detailed Phase 2 analysis. In Phase 2, selected POSs from both Grand Gulf and Surry were chosen for detailed analysis. For Grand Gulf, POS 5 (approximately cold shutdown as defined by Grand Gulf Technical Specifications) during a refueling outage was selected. For Surry, three POSs representing the time the plant spends in midloop operation were chosen for analysis. These included POS 6 and POS 10 of a refueling outage and POS 6 of a drained maintenance outage. Level 1 and Level 2/3 results from both the Surry and Grand Gulf analyses are presented.

  19. Risk contribution from low power and shutdown of a pressurized water reactor

    International Nuclear Information System (INIS)

    Chu, T.L.; Pratt, W.T.

    1997-01-01

    During 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. Two plants, Surry (a pressurized water reactor) and Grand Gulf (a boiling water reactor), were selected for study by Brookhaven National Laboratory and Sandia National Laboratories, respectively. The program objectives included assessing the risks of severe accidents initiated during plant operational states other than full power operation and comparing estimated core damage frequencies, important accident sequences, and other qualitative and quantitative results with full power accidents as assessed in NUREG-1150. The scope included a Level 3 PRA for traditional internal events and a Level 1 PRA on fire, flooding, and seismically induced core damage sequences. A phased approach was used in Level 1. In Phase 1 the concept of plant operational states (POSs) was developed to provide a better representation of the plant as it transitions from power to non power operation. This included a coarse screening analysis of all POSs to identify vulnerable plant configurations, to characterize (on a high, medium, or low basis) potential frequencies of core damage accidents, and to provide a foundation for a detailed Phase 2 analysis. In Phase 2, selected POSs from both Grand Gulf and Surry were chosen for detailed analysis. For Grand Gulf, POS 5 (approximately Cold Shutdown as defined by Grand Gulf Technical Specifications) during a refueling outage was selected. For Surry, three POSs representing the time the plant spends in mid loop operation were chosen for analysis. Level 1 and Level 2/3 results from the Surry analyses are presented

  20. Risk contribution from low power, shutdown, and other operational modes beyond full power

    International Nuclear Information System (INIS)

    Whitehead, D.W.; Brown, T.D.; Chu, T.L.; Pratt, W.T.

    1995-01-01

    During 1989 the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. Two plants, Surry (a pressurized water reactor) and Grand Gulf (a boiling water reactor), were selected for study by Brookhaven National Laboratory and Sandia National Laboratories, respectively. The program objectives included assessing the risks of severe accidents initiated during plant operational states other than full power and comparing estimated core damage frequencies, important accident sequences, and other qualitative and quantitative results with full power accidents as assessed in NUREG-1150. The scope included a Level 3 probabilistic risk assessment (PRA) for traditional internal events and a Level 1 PRA on fire, flooding, and seismically induced core damage sequences. A phased approach was used in Level 1. In Phase 1 the concept of plant operational states (POSs) was developed to provide a better representation of the plant as it transitions from power to nonpower operation. This included a coarse screening analysis of all POSs to identify vulnerable plant configurations, to characterize (on a high, medium, or low basis) potential frequencies of core damage accidents, and to provide a foundation for a detailed Phase 2 analysis. In Phase 2, selected POSs from both Grand Gulf and Surry were chosen for detailed analysis. For Grand Gulf, POS 5 (approximately cold shutdown as defined by Grand Gulf Technical Specifications) during a refueling outage was selected. For Surry, three POSs representing the time the plant spends in midloop operation were chosen for analysis. These included POS 6 and POS 10 of a refueling outage and POS 6 of a drained maintenance outage. Level 1 and Level 2/3 results from both the Surry and Grand Gulf analyses are presented

  1. Shutdown dose rate analysis with CAD geometry, Cartesian/tetrahedral mesh, and advanced variance reduction

    International Nuclear Information System (INIS)

    Biondo, Elliott D.; Davis, Andrew; Wilson, Paul P.H.

    2016-01-01

    Highlights: • A CAD-based shutdown dose rate analysis workflow has been implemented. • Cartesian and superimposed tetrahedral mesh are fully supported. • Biased and unbiased photon source sampling options are available. • Hybrid Monte Carlo/deterministic techniques accelerate photon transport. • The workflow has been validated with the FNG-ITER benchmark problem. - Abstract: In fusion energy systems (FES) high-energy neutrons born from burning plasma activate system components to form radionuclides. The biological dose rate that results from photons emitted by these radionuclides after shutdown—the shutdown dose rate (SDR)—must be quantified for maintenance planning. This can be done using the Rigorous Two-Step (R2S) method, which involves separate neutron and photon transport calculations, coupled by a nuclear inventory analysis code. The geometric complexity and highly attenuating configuration of FES motivates the use of CAD geometry and advanced variance reduction for this analysis. An R2S workflow has been created with the new capability of performing SDR analysis directly from CAD geometry with Cartesian or tetrahedral meshes and with biased photon source sampling, enabling the use of the Consistent Adjoint Driven Importance Sampling (CADIS) variance reduction technique. This workflow has been validated with the Frascati Neutron Generator (FNG)-ITER SDR benchmark using both Cartesian and tetrahedral meshes and both unbiased and biased photon source sampling. All results are within 20.4% of experimental values, which constitutes satisfactory agreement. Photon transport using CADIS is demonstrated to yield speedups as high as 8.5·10"5 for problems using the FNG geometry.

  2. Standardization of the time for the execution of HANARO start-up and shutdown procedures

    International Nuclear Information System (INIS)

    Choi, H. Y.; Lim, I. C.; Hwang, S. R.; Kang, T. J.; Youn, D. B.

    2003-01-01

    For the standardization of the time to execute HANARO start-up and shutdown procedures, code names were assigned to the individual procedures and the work time were investigated. The data recorded by the operators during start-up and shutdown were statistically analyzed. The analysis results will be used for the standardization of start-up and shutdown procedures and it will be reflected in the procedure document

  3. Analysis of HFETR shut-down state caused by loss of off-site power supply

    International Nuclear Information System (INIS)

    Wang Jinghu

    1997-01-01

    During the last 15 years, there are more than 40 unplanned shut-downs caused by loss of off-site power in HFETR. Because HFETR is a special research reactor, the author describes the shut-down state as three period. The author also discusses the influence of the number of shut-down due to loss of off-site power supply on the reactor safety, and propose some suggestions and measures to reduce the effects

  4. Lawful Permanent Residents - Annual Report

    Data.gov (United States)

    Department of Homeland Security — A lawful permanent resident (LPR) or 'green card' recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  5. The political economics of the permanent war and the political economics of the nuclear war. Strategic approaches for Latin America; La economia politica de la guerra permanente y la economia politica de la guerra nuclear. Aproximaciones estrategicas para America Latina

    Energy Technology Data Exchange (ETDEWEB)

    Gomez L, I.I

    2005-07-01

    This work treats on the hypothesis that the American imperialism uses its nuclear arsenal for reforming geographical spaces that allow him to impel its economic development in the context of the progressive exhaustion of the natural resources of the planet and of the ferocious dispute for market niches and investment destinations, and like the political and military decisions crawl to the different scenarios of economic competition. In the chapter 1 it is insinuated like has been reproduced the Warlike-industrial Complex (CBI) American from the second world postwar period until the present time in the idea of explaining like it is that it is valorized to the capital in scale enlarged starting from the denominated sector producing of destruction means and understanding that the system specifically capitalist is a system where continually the is destroyed previously taken place to manufacture a new merchandise in a luck of creative destruction. In the chapter 2, the topic of the specific contradictions of the CBI is approached that disable him to be the tip of lance of the world imperialism. The chapter 3 try on the productive linkages in the production of nuclear bombs, as well as in the production of the vectors of nuclear transportation and on the implications derived for the world security of the different industries associated to the nuclear energy (as the petroleum, the electricity, the natural gas) and to the transportation vectors of these locating which you/they are the different States where the world supremacy is disputed and that they have like one of its so many negotiation-confrontation letters its nuclear strategic arsenals. What is looked for in a thermonuclear war is the enemy's total elimination, from their offensive capacity, their defensive capacity, until their supplies, their reservations, etc., with the result that the chapters 4 and 5 of this thesis are presented to offer a better understanding that they mean the nuclear arsenals in the

  6. Level 1 probabilistic risk assessment of low power and shutdown operations at a PWR: Phase 2 results

    International Nuclear Information System (INIS)

    Chu, T.L.; Bozoki, G.; Kohut, P.; Musicki, Z.; Wong, S.M.; Yang, J.; Hsu, C.J.; Diamond, D.J.; Su, R.F.; Holmes, B.; Siu, N.; Bley, D.; Lin, J.

    1992-01-01

    As a result of the Chernobyl accident and other precursor events (e.g., Diablo Canyon), the US Nuclear Regulatory Commission's (NRC's) Office of Nuclear Regulatory Research (RES) initiated an extensive project during 1989 to carefully examine the potential risks during Low Power and Shutdown (LP ampersand S) operations. Shortly after the program began, an event occurred at the Vogtle plant during shutdown, which further intensified the effort of the LP ampersand S program. In the LP ampersand S program, one pressurized water reactor (PWR), Surry, and one boiling water reactor (BWR), Grand Gulf, were selected, mainly because they were previously analyzed in the NUREG-1150 Study. The Level-1 Program is being performed in two phases. Phase 1 was dedicated to performing a coarse screening level-1 analysis including internal fire and flood. A draft report was completed in November, 1991. In the phase 2 study, mid-loop operations at the Surry plant were analyzed in detail. The objective of this paper is to present the approach of the phase 2 study and the preliminary results and insights

  7. Communication dated 1 August 2008 received from the Permanent Mission of the Islamic Republic of Iran to the Agency concerning the text of the 'Statement on the Islamic Republic of Iran's Nuclear Issue' adopted by the XV Ministerial Conference of the Non-Aligned Movement

    International Nuclear Information System (INIS)

    2008-01-01

    The Secretariat has received a Note Verbale dated 1 August 2008 from the Permanent Mission of the Islamic Republic of Iran, attaching the text of the 'Statement on the Islamic Republic of Iran's Nuclear Issue' adopted by the XV Ministerial Conference of the Non-Aligned Movement held in Tehran from 27 to 30 July 2008. The Note Verbale and, as requested therein, its attachment are circulated herewith for the information of Member States

  8. Production capabilities in US nuclear reactors for medical radioisotopes

    International Nuclear Information System (INIS)

    Mirzadeh, S.; Callahan, A.P.; Knapp, F.F. Jr.; Schenter, R.E.

    1992-11-01

    The availability of reactor-produced radioisotopes in the United States for use in medical research and nuclear medicine has traditionally depended on facilities which are an integral part of the US national laboratories and a few reactors at universities. One exception is the reactor in Sterling Forest, New York, originally operated as part of the Cintichem (Union Carbide) system, which is currently in the process of permanent shutdown. Since there are no industry-run reactors in the US, the national laboratories and universities thus play a critical role in providing reactor-produced radioisotopes for medical research and clinical use. The goal of this survey is to provide a comprehensive summary of these production capabilities. With the temporary shutdown of the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) in November 1986, the radioisotopes required for DOE-supported radionuclide generators were made available at the Brookhaven National Laboratory (BNL) High Flux Beam Reactor (HFBR). In March 1988, however, the HFBR was temporarily shut down which forced investigators to look at other reactors for production of the radioisotopes. During this period the Missouri University Research Reactor (MURR) played an important role in providing these services. The HFIR resumed routine operation in July 1990 at 85 MW power, and the HFBR resumed operation in June 1991, at 30 MW power. At the time of the HFBR shutdown, there was no available comprehensive overview which could provide information on status of the reactors operating in the US and their capabilities for radioisotope production. The obvious need for a useful overview was thus the impetus for preparing this survey, which would provide an up-to-date summary of those reactors available in the US at both the DOE-funded national laboratories and at US universities where service irradiations are currently or expected to be conducted

  9. Production capabilities in US nuclear reactors for medical radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Mirzadeh, S.; Callahan, A.P.; Knapp, F.F. Jr. (Oak Ridge National Lab., TN (United States)); Schenter, R.E. (Westinghouse Hanford Co., Richland, WA (United States))

    1992-11-01

    The availability of reactor-produced radioisotopes in the United States for use in medical research and nuclear medicine has traditionally depended on facilities which are an integral part of the US national laboratories and a few reactors at universities. One exception is the reactor in Sterling Forest, New York, originally operated as part of the Cintichem (Union Carbide) system, which is currently in the process of permanent shutdown. Since there are no industry-run reactors in the US, the national laboratories and universities thus play a critical role in providing reactor-produced radioisotopes for medical research and clinical use. The goal of this survey is to provide a comprehensive summary of these production capabilities. With the temporary shutdown of the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) in November 1986, the radioisotopes required for DOE-supported radionuclide generators were made available at the Brookhaven National Laboratory (BNL) High Flux Beam Reactor (HFBR). In March 1988, however, the HFBR was temporarily shut down which forced investigators to look at other reactors for production of the radioisotopes. During this period the Missouri University Research Reactor (MURR) played an important role in providing these services. The HFIR resumed routine operation in July 1990 at 85 MW power, and the HFBR resumed operation in June 1991, at 30 MW power. At the time of the HFBR shutdown, there was no available comprehensive overview which could provide information on status of the reactors operating in the US and their capabilities for radioisotope production. The obvious need for a useful overview was thus the impetus for preparing this survey, which would provide an up-to-date summary of those reactors available in the US at both the DOE-funded national laboratories and at US universities where service irradiations are currently or expected to be conducted.

  10. Spent fuel acceptance scenarios devoted to shutdown reactors: A preliminary analysis

    International Nuclear Information System (INIS)

    Wood, T.W.; Plummer, A.M.; Dippold, D.G.; Short, S.M.

    1989-10-01

    Spent fuel acceptance schedules and the allocation of federal acceptance capacity among commercial nuclear power reactors have important operational and cost consequences for reactor operators. Alternative allocation schemes were investigated to some extent in DOE's MRS Systems Study. The current study supplements these analyses for a class of acceptance schemes in which the acceptance capacity of the federal radioactive waste management system is allocated principally to shutdown commercial power reactors, and extends the scope of analysis to include considerations of at-reactor cask loading rates. The operational consequences of these schemes for power reactors, as measured in terms of quantity of spent fuel storage requirement above storage pool capacities and number of years of pool operations after last discharge, are estimated, as are the associated utility costs. This study does not attempt to examine the inter-utility equity considerations involved in departures from the current oldest-fuel-first (OFF) allocation rule as specified in the ''Standard Contract for Disposal of Spent Nuclear Fuel and/or High-Level Radioactive Waste.'' In the sense that the alternative allocations are more economically efficient than OFF, however, they approximate the allocations that could result from free exchange of acceptance rights among utilities. Such a process would result in the preservation of inter-utility equity. 13 refs., 9 figs., 9 tabs

  11. Actions for continued safe wet storage of spent nuclear fuel at VVR-S reactor in Bucharest-Magurele

    International Nuclear Information System (INIS)

    Isbasescu, M.; Zorliu, A.; Silviu-laurentiu, B.; Stefan, V. . E-mail address of corresponding author: mirifa@ifin.nipne.ro; Isbasescu, M.)

    2005-01-01

    The Romanian VVR-S research reactor is located 8 kilometers from Bucharest in the town of Magurele and was operated by the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH). The reactor first reached criticality in July 1957 and operated until December 1997 when it was permanently shutdown. The VVR - S reactor of IFIN has two repositories for spent fuel elements: (1) Cooling pool located in the reactor room; (2) Long-term repositories located outside the reactor building - SNFW (spent nuclear fuel warehouse). The major factors believed to influence the pitting of aluminium alloys are conductivity, pH, and bicarbonate, chloride, sulphate and oxygen content. Some of these parameters have been analyzed at SNFW-IFIN-HH. (author)

  12. Nuclear Technology Review 2012

    International Nuclear Information System (INIS)

    2012-09-01

    In 2011, nuclear energy continued to play an important role in global electricity production despite the accident at the Fukushima Daiichi nuclear power plant (NPP). Total generating nuclear power capacity was slightly lower than in previous years due to the permanent shutdown of 13 reactors in 2011, including 8 in Germany and 4 in Japan in the wake of the accident. However, there were 7 new grid connections compared to 5 in 2010, 2 in 2009 and none in 2008. Significant growth in the use of nuclear energy worldwide is still anticipated - between 35% and 100% by 2030 - although the Agency projections for 2030 are 7-8% lower than projections made in 2010. The factors that have contributed to an increased interest in nuclear power did not change: an increasing global demand for energy, concerns about climate change, energy security and uncertainty about fossil fuel supplies. Most of the growth is still expected in countries that already have operating NPPs, especially in Asia, with China and India remaining the main centres of expansion while the Russian Federation will also remain a centre of strong growth. The 7-8% drop in projected growth for 2030 reflects an accelerated phase-out of nuclear power in Germany, some immediate shutdowns and a government review of the planned expansion in Japan, as well as temporary delays in expansion in several other countries. Measures taken by countries as a result of the Fukushima Daiichi nuclear accident have been varied. A number of countries announced reviews of their programmes. Belgium, Germany and Switzerland took additional steps to phase out nuclear power entirely while others re-emphasized their expansion plans. Many Member States carried out national safety assessment reviews in 2011 (often called 'stress tests'), and commitments were made to complete any remaining assessments promptly and to implement the necessary corrective action. In countries considering the introduction of nuclear power, interest remained strong

  13. FFTF [Fast Flux Test Facility] reactor shutdown system reliability reevaluation

    International Nuclear Information System (INIS)

    Pierce, B.F.

    1986-07-01

    The reliability analysis of the Fast Flux Test Facility reactor shutdown system was reevaluated. Failure information based on five years of plant operating experience was used to verify original reliability numbers or to establish new ones. Also, system modifications made subsequent to performance of the original analysis were incorporated into the reevaluation. Reliability calculations and sensitivity analyses were performed using a commercially available spreadsheet on a personal computer. The spreadsheet was configured so that future failures could be tracked and compared with expected failures. A number of recommendations resulted from the reevaluation including both increased and decreased surveillance intervals. All recommendations were based on meeting or exceeding existing reliability goals. Considerable cost savings will be incurred upon implementation of the recommendations

  14. CORAL and COOL during the LHC long shutdown.

    CERN Document Server

    Valassi, Andrea; Dulstra, D; Goyal, N; Salnikov, A; Trentadue, R; Wache, M

    2014-01-01

    CORAL and COOL are two software packages used by the LHC experiments for managing detector conditions and other types of data using relational database technologies. They have been developed and maintained within the LCG Persistency Framework, a common project of the CERN IT department with ATLAS, CMS and LHCb. This presentation reports on the status of CORAL and COOL at the time of CHEP2013, covering the new features and enhancements in both packages, as well as the changes and improvements in the software process infrastructure. It also reviews the usage of the software in the experiments and the outlook for ongoing and future activities during the LHC long shutdown (LS1) and beyond.

  15. CORAL and COOL during the LHC long shutdown

    CERN Multimedia

    Valassi, A; Dykstra, D; Goyal, N; Salnikov, A; Trentadue, R; Wache, M

    2013-01-01

    CORAL and COOL are two software packages used by the LHC experiments for managing detector conditions and other types of data using relational database technologies. They have been developed and maintained within the LCG Persistency Framework, a common project of the CERN IT department with ATLAS, CMS and LHCb. This presentation reports on the status of CORAL and COOL at the time of CHEP2013, covering the new features and enhancements in both packages, as well as the changes and improvements in the software process infrastructure. It also reviews the usage of the software in the experiments and the outlook for ongoing and future activities during the LHC long shutdown (LS1) and beyond.

  16. High level waste facilities - Continuing operation or orderly shutdown

    International Nuclear Information System (INIS)

    Decker, L.A.

    1998-04-01

    Two options for Environmental Impact Statement No action alternatives describe operation of the radioactive liquid waste facilities at the Idaho Chemical Processing Plant at the Idaho National Engineering and Environmental Laboratory. The first alternative describes continued operation of all facilities as planned and budgeted through 2020. Institutional control for 100 years would follow shutdown of operational facilities. Alternatively, the facilities would be shut down in an orderly fashion without completing planned activities. The facilities and associated operations are described. Remaining sodium bearing liquid waste will be converted to solid calcine in the New Waste Calcining Facility (NWCF) or will be left in the waste tanks. The calcine solids will be stored in the existing Calcine Solids Storage Facilities (CSSF). Regulatory and cost impacts are discussed

  17. Failure and Reliability Analysis for the Master Pump Shutdown System

    International Nuclear Information System (INIS)

    BEVINS, R.R.

    2000-01-01

    The Master Pump Shutdown System (MPSS) will be installed in the 200 Areas of the Hanford Site to monitor and control the transfer of liquid waste between tank farms and between the 200 West and 200 East areas through the Cross-Site Transfer Line. The Safety Function provided by the MPSS is to shutdown any waste transfer process within or between tank farms if a waste leak should occur along the selected transfer route. The MPSS, which provides this Safety Class Function, is composed of Programmable Logic Controllers (PLCs), interconnecting wires, relays, Human to Machine Interfaces (HMI), and software. These components are defined as providing a Safety Class Function and will be designated in this report as MPSS/PLC. Input signals to the MPSS/PLC are provided by leak detection systems from each of the tank farm leak detector locations along the waste transfer route. The combination of the MPSS/PLC, leak detection system, and transfer pump controller system will be referred to as MPSS/SYS. The components addressed in this analysis are associated with the MPSS/SYS. The purpose of this failure and reliability analysis is to address the following design issues of the Project Development Specification (PDS) for the MPSS/SYS (HNF 2000a): (1) Single Component Failure Criterion, (2) System Status Upon Loss of Electrical Power, (3) Physical Separation of Safety Class cables, (4) Physical Isolation of Safety Class Wiring from General Service Wiring, and (5) Meeting the MPSS/PLC Option 1b (RPP 1999) Reliability estimate. The failure and reliability analysis examined the system on a component level basis and identified any hardware or software elements that could fail and/or prevent the system from performing its intended safety function

  18. New permanent magnets

    Science.gov (United States)

    Müller, K.-H.; Krabbes, G.; Fink, J.; Gruß, S.; Kirchner, A.; Fuchs, G.; Schultz, L.

    2001-05-01

    Permanent magnets play an important role and are widely spread in daily-life applications. Due to their very low costs, large availability of the row materials and their high chemical stability, hard ferrites are still dominant in the permanent magnet market although their relatively poor magnetic properties are a distinct disadvantage. Today's high-performance magnets are mostly made from Nd 2Fe 14B. The aim of research is to combine the large spontaneous magnetization of 3d metals with strong anisotropy fields known from rare-earth transition-metal compounds and, at the same time, to maintain a high value of the Curie temperature. However, the number of iron-rich rare-earth intermetallics is very limited and, consequently, not much success can be noted in this field for the last 10 years. One alternative concept is to use magnetic fields trapped in type II superconductors where much higher fields can be achieved compared to conventional rare-earth magnets. Very recently, we obtained a trapped field as high as 14.4 T in a melt-textured YBCO bulk sample of a few centimeters in diameter. This is the highest value ever achieved in a bulk superconductor. The trapped field of a superconductor is not governed by the Laplace equation and, therefore, levitation works without any additional (active) stabilization. The disadvantage of these magnets is their low working temperature (of liquid nitrogen and below).

  19. Cryogenic Permanent Magnet Undulators

    International Nuclear Information System (INIS)

    Chavanne, J.; Lebec, G.; Penel, C.; Revol, F.; Kitegi, C.

    2010-01-01

    For an in-vacuum undulator operated at small gaps the permanent magnet material needs to be highly resistant to possible electron beam exposure. At room temperature, one generally uses Sm 2 Co 17 or high coercivity NdFeB magnets at the expense of a limited field performance. In a cryogenic permanent magnet undulator (CPMU), at a temperature of around 150 K, any NdFeB grade reveals a coercivity large enough to be radiation resistant. In particular, very high remanence NdFeB material can be used to build undulators with enhanced field and X-ray brilliance at high photon energy provided that the pre-baking of the undulator above 100 deg. C can be eliminated. The ESRF has developed a full scale 2 m long CPMU with a period of 18 mm. This prototype has been in operation on the ID6 test beamline since January 2008. A significant effort was put into the characterization of NdFeB material at low temperature, the development of dedicated magnetic measurement systems and cooling methods. The measured heat budget with beam is found to be larger than expected without compromising the smooth operation of the device. Leading on from this first experience, new CPMUs are currently being considered for the upgrade of the ESRF.

  20. EDF decommissioning programme a global commitment to safety, environment and cost efficiency of nuclear energy

    International Nuclear Information System (INIS)

    Grenouillet, J.-J.

    2002-01-01

    EDF has 9 NPPs permanently shutdown and under decommissioning. EDF considers that if the nuclear option is to remain open, it is necessary to deal with increasing public concerns for environmental and waste management issues. Therefore EDF has decided to achieve total dismantling of all shutdown reactor in the next 25 years. The Decommissioning Program has been developed including 2 stages of activities. The first stage consists of: 1) Final dismantling of Brennilis in 2015; 2) A dismantling demonstration of a PWR reactor building (Chooz A) before starting replacing the population of PWRs currently in operation; 3) Final dismantling of reactor containment of a GCR (Bugey 1) as a first of its kind. The second stage includes: 1)Dismantling of following 5 GCR (Saint Laurent A1 and A2, Chinon A1, A2 and A3); 2) Final dismantling of Chooz A and Bugey 1 in 2025. The successful implementation relies on the simplification of the regulatory process; availability of treatment, conditioning and disposal facilities and effective nuclear industry. The main issue is availability of time and waste solutions such as opening of a Very Low Waste disposal in 2003 (130 000 tons); opening of a new disposal for graphite and radiferous wastes (17 000 tons) in 2010 and opening in 2007-2008 of a centralized interim storage (BANEDA) facility for long-lived Medium Level Wastes (500 tons including filters, control rods etc)Three investigations are to be carried out for high level radioactive waste before 2006

  1. Stabilization and shutdown of Oak Ridge National Laboratory's Radioisotopes Production Facility

    International Nuclear Information System (INIS)

    Eversole, R.E.

    1992-01-01

    The Oak Ridge National Laboratory (ORNL) has been involved in the production and distribution of a variety of radioisotopes for medical, scientific and industrial applications since the late 1940s. Production of these materials was concentrated in a number of facilities primarily built in the 1950s and 1960s. Due to the age and deteriorating condition of these facilities, it was determined in 1989 that it would not be cost effective to upgrade these facilities to bring them into compliance with contemporary environmental, safety and health standards. The US Department of Energy (DOE) instructed ORNL to halt the production of isotopes in these facilities and maintain the facilities in safe standby condition while preparing a stabilization and shutdown plan. The goal was to place the former isotope production facilities in a radiologically and industrially safe condition to allow a 5-year deferral of the initiation of environmental restoration (ER) activities. In response to DOE's instructions, ORNL identified 17 facilities for shutdown, addressed the shutdown requirements for each facility, and prepared and implemented a three-phase, 4-year plan for shutdown of the facilities. The Isotopes Facilities Shutdown Program (IFSP) office was created to execute the stabilization and shutdown plan. The program is entering its third year in which the actual shutdown of the facilities is initiated. Accomplishments to date have included consolidation of all isotopes inventory into one facility, DOE approval of the IFSP Environmental Assessment (EA), and implementation of a detailed management plan for the shutdown of the facilities

  2. 40 CFR 63.310 - Requirements for startups, shutdowns, and malfunctions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Requirements for startups, shutdowns, and malfunctions. 63.310 Section 63.310 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Coke Oven Batteries § 63.310 Requirements for startups, shutdowns...

  3. 40 CFR 62.14645 - What happens during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false What happens during periods of startup... Limits § 62.14645 What happens during periods of startup, shutdown, and malfunction? (a) The emission limitations and operating limits apply at all times except during periods of CISWI unit startup, shutdown, or...

  4. 40 CFR 60.2918 - What happens during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What happens during periods of startup... of startup, shutdown, and malfunction? The emission limitations and operating limits apply at all times except during OSWI unit startups, shutdowns, or malfunctions. Performance Testing ...

  5. 40 CFR 63.2852 - What is a startup, shutdown, and malfunction plan?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true What is a startup, shutdown, and... Production Compliance Requirements § 63.2852 What is a startup, shutdown, and malfunction plan? You must...)(2) malfunction period, or the § 63.2850(c)(2) or (d)(2) initial startup period. The SSM plan must...

  6. 40 CFR 60.2685 - What happens during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What happens during periods of startup... happens during periods of startup, shutdown, and malfunction? (a) The emission limitations and operating limits apply at all times except during CISWI unit startups, shutdowns, or malfunctions. (b) Each...

  7. 40 CFR 65.6 - Startup, shutdown, and malfunction plan and procedures.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Startup, shutdown, and malfunction... (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE General Provisions § 65.6 Startup... Group 2A or Group 2B process vents. (b) Startup, shutdown, and malfunction plan—(1) Description and...

  8. 40 CFR 60.3025 - What happens during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What happens during periods of startup... during periods of startup, shutdown, and malfunction? The emission limitations and operating limits apply at all times except during OSWI unit startups, shutdowns, or malfunctions. Model Rule—Performance...

  9. 30 CFR 57.8534 - Shutdown or failure of auxiliary fans.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shutdown or failure of auxiliary fans. 57.8534... Ventilation Underground Only § 57.8534 Shutdown or failure of auxiliary fans. (a) Auxiliary fans installed and... fan maintenance or fan adjustments where air quality is maintained in compliance with the applicable...

  10. An analysis of operational experience during low power and shutdown and a plan for addressing human reliability assessment issues

    International Nuclear Information System (INIS)

    Barriere, M.; Luckas, W.; Whitehead, D.; Ramey-Smith, A.

    1994-06-01

    Recent nuclear power plant events (e.g. Chernobyl, Diablo Canyon, and Vogtle) and US Nuclear Regulatory Commission (NRC) reports (e.g. NUREG-1449) have led to concerns regarding human reliability during low power and shutdown (LP ampersand S) conditions and limitations of human reliability analysis (HRA) methodologies in adequately representing the LP ampersand S environment. As a result of these concerns, the NRC initiated two parallel research projects to assess the influence of LP ampersand S conditions on human reliability through an analysis of operational experience at pressurized water reactors (PWRs) an boiling water reactors (BWRs). These research projects, performed by Brookhaven National Laboratory for PWRS, and Sandia National Laboratories for BWRs, identified unique aspects of human performance during LP ampersand S conditions and provided a program plan for research and development necessary to improve existing HRA methodologies. This report documents the results of the analysis of LP ampersand S operating experience and describes the improved HRA program plan

  11. Nuclear power: the political challenge

    International Nuclear Information System (INIS)

    Adam, G.

    2009-01-01

    A brief overview of the political and economical situation and nuclear energy problems in Europe is given. The author presented his opinion on topic such as need of nuclear power, Kozloduy NPP units 1-4 shutdown, climate change , energy security, environmental problems

  12. Shutdown dose rate analysis of European test blanket modules shields in ITER Equatorial Port #16

    Energy Technology Data Exchange (ETDEWEB)

    Juárez, Rafael, E-mail: rjuarez@ind.uned.es [Departamento de Ingeniería Energética, ETSII-UNED, Calle Juan del Rosal 12, Madrid 28040 (Spain); Sauvan, Patrick; Perez, Lucia [Departamento de Ingeniería Energética, ETSII-UNED, Calle Juan del Rosal 12, Madrid 28040 (Spain); Panayotov, Dobromir; Vallory, Joelle; Zmitko, Milan; Poitevin, Yves [Fusion for Energy (F4E), Torres Diagonal Litoral B3, Josep Pla 2, Barcelona 08019 (Spain); Sanz, Javier [Departamento de Ingeniería Energética, ETSII-UNED, Calle Juan del Rosal 12, Madrid 28040 (Spain)

    2016-11-01

    Highlights: • Nuclear analysis for European TBMs and shields, in ITER Equatorial Port #16, has been conducted in support of the ‘Concept Design Review’ from ITER. • The objective of the work is the characterization of the Shutdown Dose Rates at Equatorial Port #16 interspace. • The role played by the TBM and TBM shields, the equatorial port gaps and the vacuum vessel permeation, in terms of neutron flux transmission is assessed. • The role played by the TBM, TBM shields, Port Plug Frame, Pipe Forest and the machine in terms of activation is also investigated. - Abstract: ‘Fusion for Energy’ (F4E) is designing, developing, and implementing the European Helium-Cooled Lead-Lithium (HCLL) and Helium-Cooled Pebble-Bed (HCPB) Test Blanket Systems (TBSs) for ITER (Nuclear Facility INB-174). An essential element of the Conceptual Design Review (CDR) of these TBSs is the demonstration of capability of Test Blanket Modules (TBM) and their shields to fulfil their function and comply with the design requirements. One of the TBM shields highly relevant design aspects is the project target for shutdown dose rates (SDDR) in the interspace. We investigated two functions of the TBMs and TBM shields—the neutron flux attenuation along the shields, and the reduction of the activation of the components contributing to SDDR. It is shown that TBMs and TBM shields reduce significantly the neutron flux in the port plug (PP). In terms of neutron flux attenuation, the TBM shield provides sufficient neutron flux reduction, being responsible for 5 × 10{sup 6} n/cm{sup 2} s at port interspace, while the EPP gaps and BSM gaps are responsible for 5 × 10{sup 7} n/cm{sup 2} s each. When considering closed upper, lower and lateral neighbour equatorial ports (thus, excluding the cross-talk between ports), a SDDR of 121 μSv/h averaged near the port closure flange was obtained, out of which, only 4 μSv/h are due to the activation of TBMs and TBM shields. Maximum SDDR in the range

  13. Experience with after-shutdown decay heat removal - BWRs and PWRs

    International Nuclear Information System (INIS)

    Haugh, J.J.; Mollerus, F.J.; Booth, H.R.

    1992-01-01

    Boiling-water reactors (BWRs) and pressurized-water reactors (PWRs) make use of residual heat removal systems (RHRSs) during reactor shutdown. RHRS operational events involving an actual loss or significant degradation of an RHRS during shutdown heat removal are often prompted or aggravated by complex, changing plant conditions and by concurrent maintenance operations. Events involving loss of coolant inventory, loss of decay heat removal capability, or inadvertent pressurization while in cold shutdown have occurred. Because fewer automatic protective fetures are operative during cold shutdowns, both prevention and termination of events depend heavily on operator action. The preservation of RHRS cooling should be an important priority in all shutdown operations, particularly where there is substantial decay heat and a reduced water inventory. 13 refs., 3 figs., 4 tabs

  14. Nuclear safety - Topical issues

    International Nuclear Information System (INIS)

    1995-01-01

    The following topical issues related to nuclear safety are discussed: steam generators; maintenance strategies; control rod drive nozzle cracks; core shrouds cracks; sump strainer blockage; fire protection; computer software important for safety; safety during shutdown; operational safety experience; external hazards and other site related issues. 5 figs, 5 tabs

  15. Reactor control and protection of full scope simulator for Qinshan 300 MW Nuclear Power Unit

    International Nuclear Information System (INIS)

    Zhu Jinping; Sun Jiliang

    1996-01-01

    The control and protection simulation of Qinshan 300 MW Nuclear Power Unit, including the nuclear control, the pressurizer pressure control, the pressurizer level control, the rod control, the reactor shutdown protection and engineered safety feature etc are briefly introduced

  16. Nuclear knowledge development in Armenia

    International Nuclear Information System (INIS)

    Gevorgyan, A.A.

    2004-01-01

    Armenia has rather rich history of nuclear knowledge development. During the last several decades, depending on circumstances related with the ANPP main mile stones - construction, putting into operation, shutdown, restarting - nuclear knowledge was having its ups and downs. Though it has high level of development, there has been yet a need of preservation accumulated nuclear knowledge, and appropriate proceeding with the nuclear knowledge in Armenia. (author)

  17. Communication Received from the Permanent Mission of Brazil regarding Certain Member States' Guidelines for the Export of Nuclear Material, Equipment and Technology; Comunicacion recibida de la Mision Permanente del Brasil relativa a las directrices de ciertos Estados Miembros para la exportacion de materiales, equipos y tecnologia nucleares

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-16

    The Agency has received a Note Verbale from the Permanent Mission of Brazil, dated 22 March 2007, in which it requests that the Agency circulate to all Member States a letter of 12 December 2006 from the Chairman of the Nuclear Suppliers Group, Ambassador Jose Artur Denot Medeiros, to the Director General, on behalf of the Governments of Argentina, Australia, Austria, Belarus, Belgium, Brazil, Bulgaria, Canada, China, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, Kazakhstan, Republic of Korea, Latvia, Lithuania, Luxemburg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russian Federation, Slovakia, Slovenia, South Africa, Spain, Sweden, Switzerland, Turkey, Ukraine, the United Kingdom of Great Britain and Northern Ireland and the United States of America, providing further information on those Governments' Guidelines for Nuclear Transfers [Spanish] El Organismo ha recibido una nota verbal de la Mision Permanente del Brasil, de fecha 22 de marzo de 2007, en la que le solicita que distribuya a todos los Estados Miembros una carta de 12 de diciembre de 2006 enviada al Director General por el Presidente del Grupo de Suministradores Nucleares, el Embajador Jose Artur Denot Medeiros, en nombre de los Gobiernos de Alemania, Argentina, Australia, Austria, Belarus, Belgica, Brasil, Bulgaria, Canada, Croacia, China, Chipre, Dinamarca, Eslovaquia, Eslovenia, Espana, Estados Unidos de America, Estonia, Federacion de Rusia, Finlandia, Francia, Grecia, Hungria, Irlanda, Italia, Japon, Kazajstan, Letonia, Lituania, Luxemburgo, Malta, Noruega, Nueva Zelandia, Paises Bajos, Polonia, Portugal, Reino Unido de Gran Bretana e Irlanda del Norte, Republica Checa, Republica de Corea, Rumania, Sudafrica, Suecia, Suiza, Turquia y Ucrania, por la que se proporciona mas informacion sobre las Directrices de esos Gobiernos para las transferencias nucleares.

  18. SCE, PG ampersand E face off with California PUC on shutdown

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    The California Public Utilities Commission (CPUC) continues its consideration of a proposal to close permanently the San Onofre nuclear station, near San Clemente, California. In its report to the full CPUC, the Division of Ratepayer Advocates (DRA) concluded that continuing to operate San Onofre was not cost-effective compared with the cost of replacement power. The DRA claims the state could save money by closing the plant and utilizing demand-side management programs and power purchases from other utilities to replace the power from San Onofre at a lower cost

  19. Risk of nuclear power generation as business (continued)

    International Nuclear Information System (INIS)

    Sato, Satoshi

    2017-01-01

    This paper described the following: (1) fleet formation of power companies that operate nuclear power plants in the U.S., (2) collaboration, competition, and merger between plant makers, (3) stress corrosion cracking of stream generators for PWR and their thin heat transfer tubes, especially stress corrosion cracking under primary cooling water environment (PWSCC), and (4) replacement project from Inconel 600 MA to Inconel 600 TT or 690 TT of steam generator thin heat transfer tubes of PWR plants in the U.S. and others. In addition, it described the troubles at San Onofre Nuclear Power Station in California: wear of steam generator thin tubes of Units 2 and 3, and leakage from primary system to secondary system of Unit 3, and permanent shutdown. It also described the detail of damages compensation talks between South California Edison Company that operates San Onofre nuclear power plant and Mitsubishi Heavy Industries Ltd. which supplied the steam generator. Although the operation of the 1.7 million kW plant became impossible due to the bud shedding of nuclear power renaissance, these troubles might have saved the nightmare of drifting on the way. (A.O.)

  20. 40 CFR 60.1710 - What happens to the emission limits during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... during periods of startup, shutdown, and malfunction? 60.1710 Section 60.1710 Protection of Environment... during periods of startup, shutdown, and malfunction? (a) The emission limits of this subpart apply at all times except during periods of municipal waste combustion unit startup, shutdown, or malfunction...

  1. 40 CFR 62.15165 - What happens to the emission limits during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... during periods of startup, shutdown, and malfunction? 62.15165 Section 62.15165 Protection of Environment... emission limits during periods of startup, shutdown, and malfunction? (a) The emission limits of this subpart apply at all times except during periods of municipal waste combustion unit startup, shutdown, or...

  2. 40 CFR 60.1205 - What happens to the operating requirements during periods of startup, shutdown, and malfunction?

    Science.gov (United States)

    2010-07-01

    ... requirements during periods of startup, shutdown, and malfunction? 60.1205 Section 60.1205 Protection of... requirements during periods of startup, shutdown, and malfunction? (a) The operating requirements of this subpart apply at all times except during periods of municipal waste combustion unit startup, shutdown, or...

  3. Interim Safety Basis for Fuel Supply Shutdown Facility

    International Nuclear Information System (INIS)

    BENECKE, M.W.

    2000-01-01

    This ISB, in conjunction with the IOSR, provides the required basis for interim operation or restrictions on interim operations and administrative controls for the facility until a SAR is prepared in accordance with the new requirements or the facility is shut down. It is concluded that the risks associated with tha current and anticipated mode of the facility, uranium disposition, clean up, and transition activities required for permanent closure, are within risk guidelines

  4. Shutdown decay heat removal analysis: Plant case studies and special issues: Summary report

    International Nuclear Information System (INIS)

    Ericson, D.M. Jr.; Cramond, W.R.; Sanders, G.A.; Hatch, S.W.

    1989-04-01

    Shutdown Decay Heat Removal Requirements has been designated as Unresolved Safety Issue (USI) A-45. The overall objectives of the USI A-45 program were to evaluate the safety adequacy of decay heat removal (DHR) systems in existing light water reactor nuclear power plants and to assess the value and impact (benefit-cost) of alternative measures for improving the overall reliability of the DHR function. To provide the technical data required to meet these objectives a program was developed that examined the state of DHR system reliability in a sample of existing plants. This program identified potential vulnerabilities and identified and established the feasibility of potential measures to improve the reliability of the DHR function. A value/impact (V/I) analysis of the more promising of such measures was conducted and documented. This report summarizes those studies. In addition, because of the evolving nature of V/I analyses in support of regulation, a number of supporting studies related to appropriate procedures and measures for the V/I analyses were also conducted. These studies are also summarized herein. This report only summarizes findings of technical studies performed by Sandia National Laboratories as part of the program to resolve this issue. 46 refs., 7 figs., 124 tabs

  5. Development of Risk Assessment Technology for Low Power, Shutdown and Digital I and C Systems

    International Nuclear Information System (INIS)

    Jang, Seung Cheol; Kang, Hyung Gook; Lim, Ho Gon; Park, Jin Hee; Eom, Heung Sub; Kim, Tae Woon; Ha, Jae Joo

    2005-04-01

    There are two technical areas to deal with in the project; the low power and shutdown probabilistic safety assessment (PSA), and the digital I and C PSA. The scope and contents of each area could be summarized as follows: Quality assessment of a LPSD PSA model for a Korean Standard Nuclear Power Plant (KSNP), Quality improvement of the KSNP LPSD PSA model in the following four technical areas; plant operating status (POS), initiating event analysis, determination of success criteria, accident sequence analysis, Development of the LPSD risk management technologies, Unavailability analysis of Digital safety systems such as Digital Plant Protection System (DPPS) and Digital Engineered Safety Feature Actuation System (DESFAS), Impact analysis of the digital safety systems on plant risks throughout of the digital plant risk models for evaluating core damage frequency (CDF) and large early release frequency (LERF), Study on the methodologies for treating digital-specific problems in the digital I and C PSA such as reliability of safety-critical software, common cause failure (CCF) of digital components, fault coverage, etc

  6. Development of Risk Assessment Technology for Low Power, Shutdown and Digital I and C Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Seung Cheol; Kang, Hyung Gook; Lim, Ho Gon; Park, Jin Hee; Eom, Heung Sub; Kim, Tae Woon; Ha, Jae Joo

    2005-04-15

    There are two technical areas to deal with in the project; the low power and shutdown probabilistic safety assessment (PSA), and the digital I and C PSA. The scope and contents of each area could be summarized as follows: Quality assessment of a LPSD PSA model for a Korean Standard Nuclear Power Plant (KSNP), Quality improvement of the KSNP LPSD PSA model in the following four technical areas; plant operating status (POS), initiating event analysis, determination of success criteria, accident sequence analysis, Development of the LPSD risk management technologies, Unavailability analysis of Digital safety systems such as Digital Plant Protection System (DPPS) and Digital Engineered Safety Feature Actuation System (DESFAS), Impact analysis of the digital safety systems on plant risks throughout of the digital plant risk models for evaluating core damage frequency (CDF) and large early release frequency (LERF), Study on the methodologies for treating digital-specific problems in the digital I and C PSA such as reliability of safety-critical software, common cause failure (CCF) of digital components, fault coverage, etc.

  7. Level 1 shutdown and low power operation of Mochovce NPP, Unit 1, Slovakia

    International Nuclear Information System (INIS)

    Halada, P.; Cillik, I.; Stojka, T.; Kuzma, M.; Prochaska, J.; Vrtik, L.

    2004-01-01

    The paper presents general approach, used methods and form of documentation of the results that have been applied within the shutdown and low power PSA (SPSA) study for Mochovce NPP, Unit 1, Slovakia. The SPSA project was realized by VUJE Trnava Inc., Slovakia in 2001-2002 years. The Level 1 SPSA study for Mochovce NPP Unit 1 covers internal events as well as internal (fires, floods and heavy load drop) and external (aircraft crash, extreme meteorological conditions, seismic event and influence of surrounding industry) hazards. Mochovce NPP consists of two operating units equipped with VVER 440/V213 reactors safety upgraded before construction finishing and operation start. 87 safety measures based on VVER 440 operational experience and international mission insights were implemented to enhance its operational and nuclear safety. The SPSA relates to full power PSA (FPSA) as a continuation of the effort to create a harmonized level 1 PSA model for all operational modes of the plant with the goal to use it for further purposes as follows: Real Time Risk Monitor, Maintenance Optimization, Technical Specifications Optimization, Living PSA. (author)

  8. Control of radio-iodine at the German reprocessing plant WAK during operation and after shutdown

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, F.J.; Herrmann, B.; Kuhn, K.D. [Wiederaufarbeitungsanlage Karlsruhe (Germany)] [and others

    1997-08-01

    During 20 years of operation 207 metric tons of oxide fuel from nuclear power reactors with 19 kg of iodine-129 had been reprocessed in the WAK plant near Karlsruhe. In January 1991 the WAK Plant was shut down. During operation iodine releases of the plant as well as the iodine distribution over the liquid and gaseous process streams had been determined. Most of the iodine is evolved into the dissolver off-gas in volatile form. The remainder is dispersed over many aqueous, organic and especially gaseous process and waste streams. After shut down of the plant in January 1991, iodine measurements in the off-gas streams have been continued up to now. Whereas the iodine-129 concentration in the dissolver off-gas dropped during six months after shutdown by three orders of magnitude, the iodine concentrations in the vessel ventilation system of the PUREX process and the cell vent system decreased only by a factor of 10 during the same period. Iodine-129 releases of the liquid high active waste storage tanks did not decrease distinctly. The removal efficiencies of the silver impregnated iodine filters in the different off-gas streams of the WAK plant depend on the iodine concentration in the off-gas. The reason of the observed dependence of the DF on the iodine-129 concentration might be due to the presence of organic iodine compounds which are difficult to remove. 13 refs., 3 figs.

  9. Management of Spent Nuclear Fuel of Nuclear Research Reactor VVR-S at the National Institute of Physics and Nuclear Engineering, Bucharest, Romania

    Science.gov (United States)

    Biro, Lucian

    2009-05-01

    The Nuclear Research Reactor VVR-S (RR-VVR-S) located in Magurele-Bucharest, Romania, was designed for research and radioisotope production. It was commissioned in 1957 and operated without any event or accident for forty years until shut down in 1997. In 2002, by government decree, it was permanently shutdown for decommissioning. The National Institute of Physics and Nuclear Engineering (IFIN-HH) is responsible for decommissioning the RR-VVR-S, the first nuclear decommissioning project in Romania. In this context, IFIN-HH prepared and obtained approval from the Romanian Nuclear Regulatory Body for the Decommissioning Plan. One of the most important aspects for decommissioning the RR-VVR-S is solving the issue of the fresh and spent nuclear fuel (SNF) stored on site in wet storage pools. In the framework of the Russian Research Reactor Fuel Return Program (RRRFR), managed by the U.S. Department of Energy and in cooperation with the International Atomic Energy Agency and the Rosatom State Corporation, Romania repatriated all fresh HEU fuel to the Russian Federation in 2003 and the HEU SNF will be repatriated to Russia in 2009. With the experience and lessons learned from this action and with the financial support of the Romanian Government it will be possible for Romania to also repatriate the LEU SNF to the Russian Federation before starting the dismantling and decontamination of the nuclear facility. [4pt] In collaboration with K. Allen, Idaho National Laboratory, USA; L. Biro, National Commission for Nuclear Activities Control, Romania; and M. Dragusin, National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania.

  10. Energy of the LHC after the 2013-2014 shutdown

    International Nuclear Information System (INIS)

    Todesco, E.; Lorin, C.; Bajko, M.

    2012-01-01

    In 2008 all the LHC main dipole circuits were trained to 5 TeV, two sectors to 6 TeV, and one sector was pushed up to 6.6 TeV. In the 5-6 TeV range, a few quenches were needed to retrain the LHC dipoles, and none for the quadrupoles. On the other hand, in the 6- 7 TeV range a larger than expected number of quenches was observed in the main dipoles. Using this limited set of data, tentative estimates were given to guess the number of quenches needed to reach nominal energy. After three years, the only additional experimental data are the retraining of the magnets individually tested at SM18, either coming from the spares or from the 3-4 sector. After presenting this additional information, we will consider the different scenarios that can be envisaged to train the LHC main magnets after the Long Shut-down 1 (LS1), the expected energy, the impact on the commissioning time and the associated risk. (authors)

  11. Sensitivity of BWR shutdown margin tests to local reactivity anomalies

    International Nuclear Information System (INIS)

    Cokinos, D.M.; Carew, J.F.

    1987-01-01

    Successful shutdown margin (SDM) demonstration is a required procedure in the startup of a newly configured boiling water reactor (BWR) core. In its most reactive condition throughout a cycle, a BWR core must be capable of being made subcritical by a specified margin with the highest worth control rod fully withdrawn and all other rods at their fully inserted positions. Two different methods are used to demonstrate SDM: (a) the adjacent-rod test and (b) the in-sequence test. In the adjacent-rod test, the strongest rod is fully withdrawn and an adjacent rod is withdrawn to reach criticality. In the in-sequence test, control rods spread throughout the core are withdrawn in a predetermined sequence of withdrawals. Larger than expected core k/sub eff/ values have been observed during the performance of BWR SDM tests. The purpose of the work summarized in this paper has been to investigated and quantify the sensitivity of both the adjacent-rod and in-sequence SDM tests to local reactivity anomalies. This was accomplished by introducing reactivity perturbations at selected four-bundle cell locations and by evaluating their effect on core reactivity in each of the two tests

  12. Operating experiences of reactor shutdown system at MAPS

    International Nuclear Information System (INIS)

    Kotteeswaran, T.J.; Subramani, V.A.; Hariharan, K.

    1997-01-01

    The reactors in Madras Atomic Power Station (MAPS), Kalpakkam are Pressurised Heavy Water Reactors (PHWR) similar to RAPS, Kota. The moderator heavy water is pumped into the calandria from dump tank to make the reactor critical. Later with the calandria level held constant at 92% FT, the further power changes are being done with the movement of adjuster rods. The moderator is held in calandria by means of helium gas pressure differential between top of calandria and dump tank located below. The shutdown of the reactor is effected by dumping the moderator water to dump tank by fast equalizing of helium gas pressure. In the revised mode of operation of moderator circuit after the moderator inlet manifold failure, the dump timing was observed to be more compared to the normal value. This was investigated and observed to be due to accumulation of D 2 O in the gas space above dump valves, which was affecting the helium equalizing flow. Also some of Indicating Alarm Meters (IAM) in protective system initiating the trip signals have failed in the unsafe mode. They have been modified to avoid the recurrence of the failures. (author)

  13. Advanced wind turbine with lift-destroying aileron for shutdown

    Science.gov (United States)

    Coleman, Clint; Juengst, Theresa M.; Zuteck, Michael D.

    1996-06-18

    An advanced aileron configuration for wind turbine rotors featuring an aileron with a bottom surface that slopes upwardly at an angle toward the nose region of the aileron. The aileron rotates about a center of rotation which is located within the envelope of the aileron, but does not protrude substantially into the air flowing past the aileron while the aileron is deflected to angles within a control range of angles. This allows for strong positive control of the rotation of the rotor. When the aileron is rotated to angles within a shutdown range of deflection angles, lift-destroying, turbulence-producing cross-flow of air through a flow gap, and turbulence created by the aileron, create sufficient drag to stop rotation of the rotor assembly. The profile of the aileron further allows the center of rotation to be located within the envelope of the aileron, at or near the centers of pressure and mass of the aileron. The location of the center of rotation optimizes aerodynamically and gyroscopically induced hinge moments and provides a fail safe configuration.

  14. [The Object Permanence Fallacy.] Commentary.

    Science.gov (United States)

    Bradley, Ben S.

    1996-01-01

    Suggests that Greenberg's challenge to the centrality of object permanence in developmental thinking reveals that developmentalists' theories about childhood speak about their own self-images. Notes that developmentalists have been guilty of not only the object permanence fallacy but also the genetic fallacy, or the mistaken belief that describing…

  15. Reliability of Offshore Wind Turbine Drivetrains based on Measured Shut-down Events

    DEFF Research Database (Denmark)

    Natarajan, Anand; Buhl, Thomas

    2015-01-01

    by initiating blade pitching to feather and also sometimes using the generator torqueas a brake mechanism. The shutdowns due to wind speed variation nearcut-out are predicted using an Inverse First Order Reliability Model(IFORM) whereby an expected annual frequency of normal shutdownsat cut-out is put forth...... normal operation and with shutdowns. The maximum coefficient of variation (CoV) due to varying wind conditions was found on the low speed shaft torsion, but the shutdowns by themselves were not seento significantly change the fatigue loads....

  16. Accident sequence analysis for a BWR [Boiling Water Reactor] during low power and shutdown operations

    International Nuclear Information System (INIS)

    Whitehead, D.W.; Hake, T.M.

    1990-01-01

    Most previous Probabilistic Risk Assessments have excluded consideration of accidents initiated in low power and shutdown modes of operation. A study of the risk associated with operation in low power and shutdown is being performed at Sandia National Laboratories for a US Boiling Water Reactor (BWR). This paper describes the proposed methodology for the analysis of the risk associated with the operation of a BWR during low power and shutdown modes and presents preliminary information resulting from the application of the methodology. 2 refs., 2 tabs

  17. Plant Operation Station for HTR-PM Low Power and Shutdown operation Probabilistic safety analysis

    International Nuclear Information System (INIS)

    Liu Tao; Tong Jiejuan

    2014-01-01

    Full range Probabilistic safety analysis (PSA) is one of key conditions for nuclear power plant (NPP) licensing according to the requirement of nuclear safety regulatory authority. High Temperature Gas Cooled Reactor Pebble-bed Module (HTR-PM) has developed construction design and prepared for the charging license application. So after the normal power operation PSA submitted for review, the Low power and Shutdown operation Probabilistic safety analysis (LSPSA) also begin. The results of LSPSA will together with prior normal power PSA results to demonstrate the safety level of HTR-PM NPP Plant Operation Station (POS) is one of important terms in LSPSA. The definition of POS lays the foundation for LSPSA modeling. POS provides initial and boundary conditions for the following event tree and fault tree model development. The aim of this paper is to describe the state-of-the-art of POS definition for HTR-PM LSPSA. As for the first attempt to the high temperature gas cooled reactor module plant, the methodology and procedure of POS definition refers to the LWR LSPSA guidance, and adds to plant initial status analysis due to the HTR-PM characteristics. A specific set of POS grouping vectors is investigate and suggested for HTR-PM NPP, which reflects the characteristics of plant modularization and on-line refueling. As a result, seven POSs are given according to the grouping vectors at the end of the paper. They will be used to the LSPSA modelling and adjusted if necessary. The papers ’work may provide reference to the analogous NPP LSPSA. (author)

  18. Cyclic movement pin mechanism for controlling a nuclear reactor

    International Nuclear Information System (INIS)

    Joly, J.G.; Martin, Jean.

    1981-01-01

    This invention concerns a recurring movement pin mechanism for controlling a nuclear reactor by shifting a neutron absorbing assembly, vertically mobile in the nuclear reactor, to adjust the power and for emergency shut-down. This mechanism ensures a continuous movement and accurate shut-down at any level of the travel height of the absorbing assembly in the core. It also prevents the impacts of the pivoting pins in the control rod slots [fr

  19. Inspection maintenance and planning of shutdown in thermal electric generating plants

    International Nuclear Information System (INIS)

    Dezordi, W.L.; Correa, D.A.; Kina, M.

    1984-01-01

    The schedule shutdown of an industrial plant and, more specifically, of an electrical generating station, is becoming increasingly important. The major parameters to be taken into account for the planning of such a shutdown are basically of economic-financial nature such as costs of the related services (materials, equipment, manpower, etc), loss of revenue caused by the station's shutdown as well as by the station availability, and other requirements expected from it by the Load Dispatch and consumers. Improving the equipment's performances and the station's availability are the fundamental objectives to be strived for. The authors present in this paper, in an abridged form, the planning tools used for thermal electric generating plants shutdowns for inspections, maintenance and design changes implementation. (Author) [pt

  20. Reload safety evaluation of boron dilution accident related to shutdown margin proportional to boron concentration

    International Nuclear Information System (INIS)

    Zee, Sung Kyun; Lee, Ki Bog; Song, Jae Woong

    1993-06-01

    This report investigates the efficient safety evaluation method and analysis procedure on Boron Dilution Accident(BDA) under the proportional shutdown margin to boron concentration. Also investigated are problems caused by applying this shutdown margin limit. Through this investigation, the safety of Kori-3 Cycle-8, Yonggwang-2 Cycle-7, Kori-4 Cycle-8 and Yonggwang-1 Cycle-8 with respect to BDA is verified. In order to satisfy the shutdown margin requirement in the Technical Specifications, it is shown that the High Flux Alarm at Shutdown Setting for Kori-4 Cycle-8 and Yonggwang-1 Cycle-8 at Mode 5 should be set at 2 or the Technical Specification should be revised. (Author)

  1. Probabilities of inherent shutdown of unprotected events in innovative liquid metal reactors

    International Nuclear Information System (INIS)

    Mueller, C.J.; Wade, D.C.

    1988-01-01

    The uncertainty in predicting the effectiveness of inherent shutdown in innovative liquid metal cooled reactors with metallic fuel results from three broad contributing areas of uncertainty: (1) the inability to exactly predict the frequency of ATWS events with potential to challenge the safety systems and require inherent shutdown; (2) the approximation of representing all such events by a selected set of ''generic scenarios''; and (3) the inability to exactly calculate the core response to the selected generic scenarios. This paper discusses the work being done to address each of these contributing areas, identifies the design and research approaches being used at Argonne National Laboratory to reducing the key contributions to uncertainties in inherent shutdown, and presents results. The conditional probabilities (given ATWS initiation) of achieving temperatures capable of defeating inherent shutdown are shown to range from /approximately/0.1% to negligible for current designs

  2. Despite the Shutdown, Rescheduled NIH Research Festival Brings Science to the Forefront | Poster

    Science.gov (United States)

    By Andrea Frydl, Contributing Writer Although it was delayed by almost a month because of the federal shutdown, the NIH Research Festival still took place at the NIH Clinical Center in Bethesda, Md., and attendance was high.

  3. Effects of shutdown chemistry on steam generator radiation levels at Point Beach Unit 2. Interim report

    International Nuclear Information System (INIS)

    Kormuth, J.W.

    1982-05-01

    A refueling shutdown chemistry test was conducted at a PWR, Point Beach Unit 2. The objective was to yield reactor coolant chemistry data during the cooldown/shutdown process which might establish a relationship between shutdown chemistry and its effects on steam generator radiation fields. Of particular concern were the effects of the presence of hydrogen in the coolant as contrasted to an oxygenated coolant. Analysis of reactor coolant samples showed a rapid soluble release (spike) in Co-58, Co-60, and nickel caused by oxygenation of the coolant. The measurement of radioisotope specific activities indicates that the material undergoing dissolution during the shutdown originated from different sources which had varying histories of activation. The test program developed no data which would support theories that oxygenation of the coolant while the steam generators are full of water contributes to increased steam generator radiation levels

  4. Station blackout with failure of wired shutdown system for AHWR

    International Nuclear Information System (INIS)

    Srivastava, A.; Contractor, A.D.; Chatterjee, B.; Kumar, Rajesh

    2015-01-01

    Advanced Heavy Water Reactor (AHWR) is a vertical pressure tube type boiling light water cooled and heavy water moderated reactor. This reactor has several advance safety features. One of the important passive design features of this reactor is that the heat removal is achieved through natural circulation of primary coolant at all power level without primary coolant pumps. Station blackout (SBO) scenario has become very important in aftermath of Fukushima event. The existing reactor has to demonstrate that design features are sufficient to mitigate the scenario whereas the new reactor design are adding specific features to tackle such scenario for prolonged period. The present study demonstrates the design features of AHWR to mitigate the SBO scenario along with failure of wired shutdown system. SBO event leads to feed water pump trip and loss of condenser vacuum which in turn results into loss of feed water and turbine trip on low condenser vacuum signal. Stoppage of steam flow to the turbine and bypass to the condenser lead to bottling up of the system, causing MHT pressure to rise. In the absence of reactor scram, the pressure continues to rise. Isolation Condenser (IC) valve starts opening at a pressure of 7.65 MPa. The pressure continues to rise as IC system is designed for decay heat removal and reactor power is brought down to decay power level through Passive Poison Injection System (PPIS) when the pressure reaches 8.4 MPa. The analysis shows that the event do not lead to undesirable clad surface temperature rise due to reactor trip by PPIS and decay heat removal for prolonged time by IC system. Thermal hydraulic response of different parameters like pressure, temperatures, and flows in MHT system is analyzed for this scenario. Pressure during transient is found to be well below the system pressure criteria of 110% of design pressure. This analysis highlights the design robustness of AHWR. (author)

  5. Interim safety basis for fuel supply shutdown facility

    International Nuclear Information System (INIS)

    Brehm, J.R.; Deobald, T.L.; Benecke, M.W.; Remaize, J.A.

    1995-01-01

    This ISB in conjunction with the new TSRs, will provide the required basis for interim operation or restrictions on interim operations and administrative controls for the Facility until a SAR is prepared in accordance with the new requirements. It is concluded that the risk associated with the current operational mode of the Facility, uranium closure, clean up, and transition activities required for permanent closure, are within Risk Acceptance Guidelines. The Facility is classified as a Moderate Hazard Facility because of the potential for an unmitigated fire associated with the uranium storage buildings

  6. Topology optimized permanent magnet systems

    Science.gov (United States)

    Bjørk, R.; Bahl, C. R. H.; Insinga, A. R.

    2017-09-01

    Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. The Halbach cylinder is topology optimized with iron and an increase of 15% in magnetic efficiency is shown. A topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111%. Finally, a permanent magnet with alternating high and low field regions is topology optimized and a Λcool figure of merit of 0.472 is reached, which is an increase of 100% compared to a previous optimized design.

  7. Topology optimized permanent magnet systems

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian; Insinga, Andrea Roberto

    2017-01-01

    Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. The Halbach cylinder is topology optimized with iron...... and an increase of 15% in magnetic efficiency is shown. A topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111%. Finally, a permanent magnet with alternating high and low field regions is topology optimized and a ΛcoolΛcool figure of merit of 0...

  8. Periodic permanent magnet focused klystron

    Science.gov (United States)

    Ferguson, Patrick; Read, Michael; Ives, R Lawrence

    2015-04-21

    A periodic permanent magnet (PPM) klystron has beam transport structures and RF cavity structures, each of which has permanent magnets placed substantially equidistant from a beam tunnel formed about the central axis, and which are also outside the extent of a cooling chamber. The RF cavity sections also have permanent magnets which are placed substantially equidistant from the beam tunnel, but which include an RF cavity coupling to the beam tunnel for enhancement of RF carried by an electron beam in the beam tunnel.

  9. Communication of 7 August 2007 from the Permanent Mission of Pakistan to the IAEA concerning the establishment of the oversight Board to monitor the implementation of Pakistan's export control on goods, technologies, materials and equipment related to nuclear and biological weapons and their Delivery Systems Act (Act No.V) 2004

    International Nuclear Information System (INIS)

    2007-01-01

    The Secretariat has received a Note Verbale dated 7 August 2007 from the Permanent Mission of Pakistan enclosing a copy of the Gazette of Pakistan S.R.O. No.693(I)/2007, dated 11 July 2007, regarding the establishment of the Oversight Board to monitor the implementation of Pakistan's Export Control on Goods, Technologies, Materials and Equipment related to Nuclear and Biological Weapons and their Delivery Systems Act (Act No.V) 2004, including the formation and functioning of Strategic Export Control Division. As requested in the Note Verbale, the Note Verbale and the enclosure thereto are circulated for the information of Member States

  10. Electricite de France Strategy for its nuclear power plants' decommissioning programme

    International Nuclear Information System (INIS)

    Knockaert, J.M.; Gatineau, J.P.

    1992-01-01

    Although final shutdown of the first large PWR Power Stations should not occur before 2015, Electricity of France is nevertheless directly concerned by the decommissioning of its nuclear plants. The shutdown programme of the gas-graphite units is in progress and the medium-power PWR plant (300 MWe) installed at Chooz in the Ardennes will be finally shutdown at the end of 1991. This solution requires EDF to have a policy available which enables it to simultaneously run the double operation 'Plant shutdown-decommissioning' and 'New constructions-increasing available power' from both the technical and financial viewpoints. (author)

  11. Failure of PWR-RHRS under cold shutdown conditions: Experimental results from the PKL test facility

    International Nuclear Information System (INIS)

    Mandl, R.M.; Umminger, K.J.; Logt, J.V.D.

    1991-01-01

    The Residual Heat Removal System (RHRS) of a PWR is designed to transfer thermal energy from the core after plant shutdown and maintain the plant in cold shutdown or refuelling conditions for extended periods of time. Initial reactor cooling after shutdown is achieved by dissipating heat through the steam generators (SGs) and discharging steam to the condenser by means of the Turbine Bypass System (TBS). When the reactor coolant temperature has dropped to about 160C and pressure has been reduced to 30 bar the RHRS is placed into operation. it reduces the coolant temperature to 50C within 20 hours after shutdown. The time margin for establishing alternate methods of heat removal following a failure of the RHRS depends on the Reactor Coolant System (RCS) temperature, the decay heat rate and the amount of RCS inventory. During some shutdown operations the RCS may be partially drained (e. g. to perform SG inspections). Decreased primary system inventory can significantly reduce the time available to recover the RHRS's function prior to bulk boiling and possible core uncovery. In the PKL test facility, which simulates a 1,300 MWe 4-loop PWR on a scale 1:145, a failure of RHRS under cold shutdown conditions was performed. This presentation gives a brief description of the test facility followed by the test objectives and results of this experiment

  12. Reactor shutdowns loom up for 1980s as nation moves deeper into spent fuel pickle

    International Nuclear Information System (INIS)

    Kowal, D.J.

    1977-01-01

    The U.S. faces a short-term problem of inadequate electric generating capacity and a long-term problem of nuclear weapons proliferation unless a solution is found to the impasse over spent-fuel reprocessing. The Carter Administration policy of deferring commercial reprocessing indefinitely conflicts with its inaction in constructing permanent storage facilities. The dilemma, due to an abrupt change of direction after 20 years of government support for commercial reprocessing, is traced to India's 1974 nuclear explosion and a subsequent reassessment of proliferation risks. The economic impact of present U.S. policies is expected to be a significant increase in the price of uranium, while trade negotiations, based to some extent on the U.S. nuclear industry and uranium enrichment capability, could suffer. Indications are noted that the Administration may be reassessing whether the U.S. can determine the worldwide nuclear energy future, or if the net result will be to deprive the U.S. of an important energy source. The case is developed for reprocessing and co-location of facilities for security reasons, with an immediate program for expanding storage capacity

  13. United States nuclear regulatory commission program for inspection of decommissioning nuclear power plants

    International Nuclear Information System (INIS)

    Harris, P.W.

    2001-01-01

    The United States Nuclear Regulatory Commission (USNRC or Commission) has been inspecting decommissioning commercial nuclear power plants in the United States (U.S.) since the first such facility permanently shutdown in September 1967. Decommissioning inspections have principally focused on the safe storage and maintenance of spent reactor fuel; occupational radiation exposure; environmental radiological releases; the dismantlement and decontamination of structures, systems, and components identified to contain or potentially contain licensed radioactive material; and the performance of final radiological survey of the site and remaining structures to support termination of the USNRC-issued operating license. Over the last 5 years, USNRC inspection effort in these areas has been assessed and found to provide reasonable confidence that decommissioning can be conducted safely and in accordance with Commission rules and regulations. Recently, the staff has achieved a better understanding of the risks associated with particular decommissioning accidents 1 and plans to apply these insights to amendments proposed to enhance decommissioning rules and regulations. The probabilities, scenarios, and conclusions resulting from this effort are being assessed as to their applicability to the inspection of decommissioning commercial power reactors. (author)

  14. United States nuclear regulatory commission program for inspection of decommissioning nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Harris, P.W. [U.S. Nuclear Regulatory Commission, Washington, DC (United States)

    2001-07-01

    The United States Nuclear Regulatory Commission (USNRC or Commission) has been inspecting decommissioning commercial nuclear power plants in the United States (U.S.) since the first such facility permanently shutdown in September 1967. Decommissioning inspections have principally focused on the safe storage and maintenance of spent reactor fuel; occupational radiation exposure; environmental radiological releases; the dismantlement and decontamination of structures, systems, and components identified to contain or potentially contain licensed radioactive material; and the performance of final radiological survey of the site and remaining structures to support termination of the USNRC-issued operating license. Over the last 5 years, USNRC inspection effort in these areas has been assessed and found to provide reasonable confidence that decommissioning can be conducted safely and in accordance with Commission rules and regulations. Recently, the staff has achieved a better understanding of the risks associated with particular decommissioning accidents 1 and plans to apply these insights to amendments proposed to enhance decommissioning rules and regulations. The probabilities, scenarios, and conclusions resulting from this effort are being assessed as to their applicability to the inspection of decommissioning commercial power reactors. (author)

  15. Nuclear

    International Nuclear Information System (INIS)

    2014-01-01

    This document proposes a presentation and discussion of the main notions, issues, principles, or characteristics related to nuclear energy: radioactivity (presence in the environment, explanation, measurement, periods and activities, low doses, applications), fuel cycle (front end, mining and ore concentration, refining and conversion, fuel fabrication, in the reactor, back end with reprocessing and recycling, transport), the future of the thorium-based fuel cycle (motivations, benefits and drawbacks), nuclear reactors (principles of fission reactors, reactor types, PWR reactors, BWR, heavy-water reactor, high temperature reactor of HTR, future reactors), nuclear wastes (classification, packaging and storage, legal aspects, vitrification, choice of a deep storage option, quantities and costs, foreign practices), radioactive releases of nuclear installations (main released radio-elements, radioactive releases by nuclear reactors and by La Hague plant, gaseous and liquid effluents, impact of releases, regulation), the OSPAR Convention, management and safety of nuclear activities (from control to quality insurance, to quality management and to sustainable development), national safety bodies (mission, means, organisation and activities of ASN, IRSN, HCTISN), international bodies, nuclear and medicine (applications of radioactivity, medical imagery, radiotherapy, doses in nuclear medicine, implementation, the accident in Epinal), nuclear and R and D (past R and D programmes and expenses, main actors in France and present funding, main R and D axis, international cooperation)

  16. Lawful Permanent Residents Fiscal Year 2014 Country

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  17. Lawful Permanent Residents Fiscal Year 2011 State

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  18. Lawful Permanent Residents Fiscal Year 2015 Country

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  19. Lawful Permanent Residents Fiscal Year 2016 State

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  20. Lawful Permanent Residents Fiscal Year 2014 State

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...