Configuration of risk monitor system by plant defense-in-depth risk monitor and reliability monitor

International Nuclear Information System (INIS)

Yoshikawa, Hidekazu; Lind Morten; Yang Ming; Hashim Muhammad; Zhang Zhijian

2012-01-01

A new method of risk monitor system of a nuclear power plant has been proposed from the aspect by what degree of safety functions incorporated in the plant system is maintained by multiple barriers of defense-in-depth (DiD). Wherein, the central idea is plant DiD risk monitor and reliability monitor derived from the five aspects of (1) design principle of nuclear safety based on DiD concept, (2) definition of risk and risk to be monitored, (3) severe accident phenomena as major risk, (4) scheme of risk ranking, and (5) dynamic risk display. In this paper, the overall frame of the proposed risk monitor system is summarized and the detailed discussion is made on major items such as definition of risk and risk ranking, anatomy of fault occurrence, two-layer configuration of risk monitor, how to configure individual elements of plant DiD risk monitor, and lastly how to apply for a PWR safety system. (author)

Configuration of Risk Monitor System by PLant Defense-In.Depth Monitor and Relability Monitor

DEFF Research Database (Denmark)

Yoshikawa, Hidekazu; Lind, Morten; Yang, Ming

2012-01-01

A new method of risk monitor system of a nuclear power plant has been proposed from the aspect by what degree of safety functions incorporated in the plant system is maintained by multiple barriers of defense-in-depth (DiD). Wherein, the central idea is plant DiD risk monitor and reliability...... monitor derived from the four aspects of (i) design principle of nuclear safety to realize DiD concept, (ii) definition of risk and risk to be monitored, (iii) severe accident phenomena as major risk, (iv) scheme of risk ranking, and (v) dynamic risk display. In this paper, the overall frame...... of the proposed frame on risk monitor system is summarized and the detailed discussion is made on the definitions of major terminologies of risk, risk ranking, anatomy of fault occurrence, two-layer configuration of risk monitor, how to configure individual elements of plant DiD risk monitor and its example...

Modeling and Analyzing Intrusion Attempts to a Computer Network Operating in a Defense in Depth Posture

National Research Council Canada - National Science Library

Givens, Mark

2004-01-01

In order to ensure the confidentially, integrity, and availability of networked resources operating on the Global Information Grid, the Department of Defense has incorporated a "Defense-in-Depth" posture...

Defense-in-depth and diversity assessment of the RESAR-414 Integrated Protection System

International Nuclear Information System (INIS)

1979-01-01

This report discusses the defense-in-depth and diversity principles as they apply to safety related instrumentation and presents guidelines which can be used to assess the degree to which the designs of complex, interconnected safety systems conform to these principles. These guidelines are based on the use of the block concept, an approach in which the components and modules of the system are aggregated into a small number of functional units, or blocks, to simplify the analysis. It is believed that the use of the block concept and the guidelines will result in a conservative assessment of the capability of such systems to function when subjected to postulated to common-mode failures. A preliminary assessment of the RESAR-414 Integrated Protection System by means of the guidelines is also presented. The results of this assessment support the conclusion that, for purposes of a preliminary design approval, the RESAR-414 Integrated Protection System is acceptable. However, the assessment, has also resulted in requirements for additional analyses and tests, the results of which must demonstrate conformance to the guidelines prior to the issuance of a Final Design Approval

Defence-in-depth and new reactors

International Nuclear Information System (INIS)

Bonaca, M.

2002-01-01

Defense-in-Depth (DID) is the structured approach to nuclear reactor safety that is at the basis of the safety features of the current generation of operating plants. This approach developed as a means of compensating for uncertainties in equipment and human performance, and it has evolved since the 1950's from its early use as a reactor safety guiding principle to its current broad, systematic application as an overall safety philosophy incorporating lessons learned from the current generation of operating reactors. The NRC white paper on risk-informed and performance based regulation defines DID as ''...an element of the NRC's Safety Philosophy that employs successive compensatory measures to prevent accidents or mitigate damage if a malfunction, accident, or naturally caused event occurs at a nuclear facility. This philosophy ensures that safety will not be wholly dependent on any single element...The net effect of incorporating defense-in-depth...is that the facility...tends to be more tolerant of failures and external challenges''. In practical terms, DID results from the implementation of multiple measures to prevent and mitigate accidents, to contain their consequences, and to establish an acceptable balance between prevention and mitigation. Its pervasive application in reactor safety design and regulation is translated into many precepts and technical requirements of the current body of regulation. (author)

Flood risk and economically optimal safety targets for coastal flood defense systems

NARCIS (Netherlands)

Dupuits, E.J.C.; Schweckendiek, T.

2015-01-01

A front defense can improve the reliability of a rear defense in a coastal flood defense system. The influence of this interdependency on the accompanying economically optimal safety targets of both front and rear defense is investigated. The results preliminary suggest that the optimal safety level

Reactor system safety assurance

International Nuclear Information System (INIS)

Mattson, R.J.

1984-01-01

The philosophy of reactor safety is that design should follow established and conservative engineering practices, there should be safety margins in all modes of plant operation, special systems should be provided for accidents, and safety systems should have redundant components. This philosophy provides ''defense in depth.'' Additionally, the safety of nuclear power plants relies on ''safety systems'' to assure acceptable response to design basis events. Operating experience has shown the need to study plant response to more frequent upset conditions and to account for the influence of operators and non-safety systems on overall performance. Defense in depth is being supplemented by risk and reliability assessment

Improvements in Defense in Depth in French Nuclear Power Plants Following Fukushima Accidents

Energy Technology Data Exchange (ETDEWEB)

Barbaud, J. [EDF SEPTEN, Villeurbanne Cedex (France); Pouget-Abadie, X., E-mail: jean.barbaud@edf.fr [EDF DIN Headquarters, Saint-Denis (France)

2014-10-15

The accidents which occurred in the nuclear power plants in Fukushima-Daiichi resulted in a complementary safety assessment (CSA or stress-tests) of all French NPPs to confirm their compliance with their design bases and to evaluate their behaviour beyond it. They have shown that nuclear facilities have a satisfactory level of safety, but it had been decided to significantly improve their robustness to extreme situations, beyond the safety margins they have already. Planned improvements include several parts, where the main ones are the implementation of a hardened safety core (HSC) of key components for the management of extreme situations resulting from a hazard beyond the design and deployment of a nuclear rapid response force (FARN). The hardened safety core aims to avoid massive releases and lasting effects in the environment. It relies on existing or new components designed or verified to hazards with significant margins compared to the design levels of NPP beyond. It also includes provisions allowing crisis management, including crisis centre and communication means. The FARN complements the HSC and the crisis organization to bring from off-site sufficient human and material resources to increase the autonomy of the site. All these improvement contribute to a better defence in depth. (author)

Safety Culture as a Pillar of Defense-in-Depth Implementation at the Experimental Fuel Element Installation, Batan Indonesia

Energy Technology Data Exchange (ETDEWEB)

Hardiyanti, H.; Herutomo, B.; Suryaman, G.K., E-mail: hrdyanti@batan.go.id [Center for Nuclear Fuel Technology – National Nuclear Energy Agency (BATAN) Tangerang (Indonesia)

2014-10-15

Defence-in-depth (DID) needs to be implemented not only in a nuclear power plant, but also in a non-reactor nuclear facility. The application of safety culture in a nuclear facility is one way of DID implementation. Safety culture aims at the performance of safe works, the prevention of deviation, and the accomplishment of quality operation. It is in accordance with the first level of DID concept which is the prevention of abnormal operation and failures that is done through conservative design and high quality in construction and operation. Experimental Fuel Element Installation (EFEI) is a nonreactor nuclear facility that belongs to BATAN (the National Nuclear Energy Agency of the Republic of Indonesia) that functions as its research and development facility on power reactor fuel production. The objective of safety culture implementation in the EFEI is to encourage workers to have a stronger sense of responsibility on safety and to contribute actively for its development. The enhancement of safety culture in the EFEI refers to the attributes of a strong safety culture listed in the IAEA Safety Standard Series No.GS-G-3.5 (The Management System for Nuclear Installations Safety Guide). The strategies performed were: a) Internalization of safety values through activities such as briefings, “coffee morning”, visual management, workshops, and training; b) Enhancement of leadership effectiveness through activities such as senior management visits, safety leadership training, and personnel qualification training; c) Integration of safety into all work processes through activities such as setting up HIRADC (hazard identification, risk assessment, and determining controls) documents, setting up WHA (workplace hazard assessment), and routine housekeeping; d) Learning about safety through activities such as occupational health and safety inspections, safety self-assessments, open reporting on safety incidents, and participation in the FINAS (fuel incident notification

Safety issues at the defense production reactors

International Nuclear Information System (INIS)

1987-01-01

The United States produces plutonium and tritium for use in nuclear weapons at the defense production reactors endash the N Reactor in Washington and the Savannah River reactors in South Carolina. This report reaches general conclusions about the management of those reactors and highlights a number of safety and technical issues that should be resolved. The report provides an assessment of the safety management, safety review, and safety methodology employed by the Department of Energy and the private contractors who operate the reactors for the federal government. The report is necessarily based on a limited review of the defense production reactors. It does not address whether any of the reactors are ''safe,'' because such an analysis would involve a determination of acceptable risk endash a matter of obvious importance, but one that was beyond the purview of the committee. It also does not address whether the safety of the production reactors is comparable to that of commercial nuclear power stations, because even this narrower question extended beyond the charge to the committee and would have involved detailed analyses that the committee could not undertake

IAEA safety fundamentals: the safety of nuclear installations and the defence in depth concept

International Nuclear Information System (INIS)

Aro, I.

2005-01-01

This presentation is a replica of the similar presentation provided by the IAEA Basic Professional Training Course on Nuclear Safety. The presentation utilizes the IAEA Safety Series document No. 110, Safety Fundamentals: the Safety of Nuclear Installations. The objective of the presentation is to provide the basic rationale for actions in provision of nuclear safety. The presentation also provides basis to understand national nuclear safety requirements. There are three Safety Fundamentals documents in the IAEA Safety Series: one for nuclear safety, one for radiation safety and one for waste safety. The IAEA is currently revising its Safety Fundamentals by combining them into one general Safety Fundamentals document. The IAEA Safety Fundamentals are not binding requirements to the Member States. But, a very similar text has been provided in the Convention on Nuclear Safety which is legally binding for the Member State after ratification by the Parliament. This presentation concentrates on nuclear safety. The Safety Fundamentals documents are the 'policy documents' of the IAEA Safety Standards Series. They state the basic objectives, concepts and principles involved in ensuring protection and safety in the development and application of atomic energy for peaceful purposes. They will state - without providing technical details and without going into the application of principles - the rationale for actions necessary in meeting Safety Requirements. Chapter 7 of this presentation describes the basic features of defence in depth concept which is referred to in the Safety Fundamentals document. The defence in depth concept is a key issue in reaching high level of safety specifically at the design stage but as the reader can see the extended concept also refers to the operational stage. The appendix has been taken directly from the IAEA Basic Professional Training Course on Nuclear Safety and applied to the Finnish conditions. The text originates from the references

Defence-in-depth and development of safety requirements for advanced nuclear reactors

International Nuclear Information System (INIS)

Carnino, A.; Gasparini, M.

2002-01-01

The paper addresses a general approach for the preparation of the design safety requirements using the IAEA Safety Objectives and the strategy of defence-in-depth. It proposes a general method (top-down approach) to prepare safety requirements for a given kind of reactor using the IAEA requirements for nuclear power plants as a starting point through a critical interpretation and application of the strategy of defence-in-depth. The IAEA has recently developed a general methodology for screening the defence-in-depth of nuclear power plants starting from the fundamental safety objectives as proposed in the IAEA Safety Fundamentals. This methodology may provide a useful tool for the preparation of safety requirements for the design and operation of any kind of reactor. Currently the IAEA is preparing the technical basis for the development of safety requirements for Modular High Temperature Gas Reactors, with the aim of showing the viability of the method. A draft TECDOC has been prepared and circulated among several experts for comments. This paper is largely based on the content of the draft TECDOC. (authors)

Regulatory point of view on defense in depth approach to fire protection in nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Rinta-Filppula, Samu; Lehto, Matti; Vaelikangas, Pekka [Radiation and Nuclear Safety Authority STUK, Helsinki (Finland)

2015-12-15

The defense-in-depth (DiD) principle is a relatively new approach to fire protection design, even though DiD has been used in nuclear power plant (NPP) safety evaluation and design for decades (IAEA 75-INSAG-3, Rev. 1/INSAG-12). It is the main design criterion in fire protection in the latest edition of Finnish Radiation and Nuclear Safety Authority (STUK) issued guide YVL B.8 for the fire protection in nuclear facilities. The DiD approach to fire protection consists of four levels of defense: preventing the ignition of fires, detecting and extinguishing of ignited fires, preventing fire growth and spreading, confining the fire so that safety functions can be performed irrespective of the effects of the fire. The design of fire protection should take all these levels into account so that fire protection is well balanced and not dependent on a single fire protection factor or level of DiD. Despite being central to the design of fire protection, corresponding evaluations of DiD are done according to more or less unambiguous methods. The main goal of this study is to start the development of such, as much as possible, unambiguous systematic and logical method. First issue then is to build a picture of how fire safety features are executed on different levels of DiD and what is the corresponding safety importance to NPP. The Loviisa NPP was studied as an example case due to a long history of fire safety improvements since commissioning in 1977. The improvements are sorted qualitatively by their means of fire safety impact and level of DiD approach to fire protection and general plant DiD. The correspondence between the two DiD principles is an interesting issue which is discussed in this paper. Finally, Fire PRA is used to determine the safety importance of the improvements. The method proposed for the evaluation of DiD approach to fire protection is a combined ignition root cause analysis - event tree of fire scenario - consequential failure modes and effects analysis

Assessment of Factors Associated with the Safety Depth of GV15 Yamen

Directory of Open Access Journals (Sweden)

Park Soo-Jung

2014-03-01

Full Text Available Objectives: Yamen is the fifteenth acupoint of the Governor Vessel Meridian (GV15. It is anatomically close to the medulla oblongata, so finding the safety depth of the acupoint is very important. However, few studies on the safety depth of GV15 have been done. Methods: This study tried to measure the safety depth of GV15 by using magnetic resonance imaging (MRI scans and to analyze the factors affecting the safety depth through multiple regression analyses. This study was carried out for patients who had a brain MRI scan while visiting Jeonju Wonkwang Hospital, Korea. The shortest distance between the glabella and the occipital protuberance (DGO, the horizontal distance between the glabella and the back of the head (DGB and the dangerous depth (DD were measured from the sagittal views of the MRI images. The DD is the horizontal distance from the skin’s surface at GV15 to the spinal dura mater. Results: The model suggested that the safety depth (SD was significantly associated with gender (β = 0.474, P < 0.0001, DGO (β = 0.272, P = 0.027, and BMI (β = 0.249, P = 0.005 and the combination of three variables can explain the SD, with R2 = 0.571 (Table 3 A longer SD was associated with males and with greater BMI and DGO. Conclusion: This study suggests that gender, BMI and DGO may be important factors when the SD of GV15 is considered clinically through a multiple regression analysis of GV15.

The PSA assessment of Defense in Depth Memorandum and proposals

International Nuclear Information System (INIS)

Fiorini, Gian-Luigi; La Rovere, Stefano

2016-01-01

This report concerns the peculiar roles of the Defence-in-Depth (DiD) concept and the Probabilistic Safety Assessment (PSA) approach for the optimization of the safety performances of the nuclear installation. It proposes a conceptual framework and related process for the assessment of the 'safety architecture' implementing DiD, which is articulated in four main steps devoted to (1) the formulation of the safety objectives, (2) the identification of loads and environmental conditions, (3) the representation of the safety architecture and (4) the evaluation of the physical performance and reliability of the levels of DiD. A final additional step achieves the practical assessment of the safety architecture and the corresponding DiD with the support of the PSA. The comprehensive safety assessment of the implemented architecture needs its multi-dimensional representation, i.e. for given initiating event, sequence of possible failures, affected safety function and level of DiD. The risk space (frequency/probability of occurrence, versus consequences) is the framework for the integration between the DiD concept and the PSA approach. Additional qualitative key-notions are introduced in order to address the compliance of the safety architecture with a number of international safety requirements. In this context, the role of the PSA is no longer limited to the verification of the fulfilment of probabilistic targets but includes different contributions to the assessment of the DiD identified in this report. (authors)

Waste Encapsulation and Storage Facility interim operational safety requirements

CERN Document Server

Covey, L I

2000-01-01

The Interim Operational Safety Requirements (IOSRs) for the Waste Encapsulation and Storage Facility (WESF) define acceptable conditions, safe boundaries, bases thereof, and management or administrative controls required to ensure safe operation during receipt and inspection of cesium and strontium capsules from private irradiators; decontamination of the capsules and equipment; surveillance of the stored capsules; and maintenance activities. Controls required for public safety, significant defense-in-depth, significant worker safety, and for maintaining radiological consequences below risk evaluation guidelines (EGs) are included.

Safety assessment of inter-channel / inter-system digital communications: A defensive measures approach

International Nuclear Information System (INIS)

Thuy, N. N. Q.

2006-01-01

Inappropriately designed inter-channel and inter-system digital communications could initiate common cause failure of multiple channels or multiple systems. Defensive measures were introduced in EPRI report TR-1002835 (Guideline for Performing Defense-in-Depth and Diversity Assessments for Digital Upgrades) to assess, on a deterministic basis, the susceptibility of digital systems architectures to common-cause failures. This paper suggests how this approach could be applied to assess inter-channel and inter-system digital communications from a safety standpoint. The first step of the approach is to systematically identify the so called 'influence factors' that one end of the data communication path can have on the other. Potential factors to be considered would typically include data values, data volumes and data rates. The second step of the approach is to characterize the ways possible failures of a given end of the communication path could affect these influence factors (e.g., incorrect data values, excessive data rates, time-outs, incorrect data volumes). The third step is to analyze the designed-in measures taken to guarantee independence of the other end. In addition to classical error detection and correction codes, typical defensive measures are one-way data communication, fixed-rate data communication, fixed-volume data communication, validation of data values. (authors)

Annual report to Congress: Department of Energy activities relating to the Defense Nuclear Facilities Safety Board, Calendar Year 1999

International Nuclear Information System (INIS)

2000-01-01

This is the tenth Annual Report to the Congress describing Department of Energy activities in response to formal recommendations and other interactions with the Defense Nuclear Facilities Safety Board (Board). The Board, an independent executive-branch agency established in 1988, provides advice and recommendations to the Secretary of Energy regarding public health and safety issues at the Department's defense nuclear facilities. The Board also reviews and evaluates the content and implementation of health and safety standards, as well as other requirements, relating to the design, construction, operation, and decommissioning of the Department's defense nuclear facilities. During 1999, Departmental activities resulted in the closure of nine Board recommendations. In addition, the Department has completed all implementation plan milestones associated with three Board recommendations. One new Board recommendation was received and accepted by the Department in 1999, and a new implementation plan is being developed to address this recommendation. The Department has also made significant progress with a number of broad-based initiatives to improve safety. These include expanded implementation of integrated safety management at field sites, opening of a repository for long-term storage of transuranic wastes, and continued progress on stabilizing excess nuclear materials to achieve significant risk reduction

Modeling Safety Barriers and Defense in Depth with Mulitlevel Flow Modeling

DEFF Research Database (Denmark)

Lind, Morten

2012-01-01

in MFM is a barrier function. It is shown that other barrier types can be represented andthat their combination into barrier chains may be used to analyze and design levels of safety in automated processes.Suggestion for further research on barrier modeling with MFM are included....

Cold Vacuum Drying (CVD) Facility Technical Safety Requirements

International Nuclear Information System (INIS)

KRAHN, D.E.

2000-01-01

The Technical Safety Requirements (TSRs) for the Cold Vacuum Drying Facility define acceptable conditions, safe boundaries, bases thereof, and management or administrative controls required to ensure safe operation during receipt of multi-canister overpacks (MCOs) containing spent nuclear fuel. removal of free water from the MCOs using the cold vacuum drying process, and inerting and testing of the MCOs before transport to the Canister Storage Building. Controls required for public safety, significant defense in depth, significant worker safety, and for maintaining radiological and toxicological consequences below risk evaluation guidelines are included

76 FR 2151 - Assumption Buster Workshop: Defense-in-Depth is a Smart Investment for Cyber Security

Science.gov (United States)

2011-01-12

... day-long workshop on the pros and cons of the defense-in-depth strategy for cyber security. The... Technology Research and Development (NITRD) Program. ACTION: Call for participation. FOR FURTHER INFORMATION... Information Technology Research and Development (NITRD) Program on behalf of the SCORE Committee. Background...

Safety issues at the defense production reactors

International Nuclear Information System (INIS)

1987-01-01

The United States produces plutonium and tritium for use in nuclear weapons at the defense production reactors - the N Reactor in Washington and the Savannah River reactors in South Carolina. This report reaches general conclusions about the management of those reactors and highlights a number of safety and technical issues that should be resolved. The report provides an assessment of the safety management, safety review, and safety methodology employed by the Department of Energy and the private contractors who operate the reactors for the federal government. This report examines the safety objective established by the Department of Energy for the production reactors and the process the Department of its contractors use to implement the objective; focuses on a variety of uncertainties concerning the production reactors, particularly those related to potential vulnerabilities to severe accidents; and identifies ways in which the DOE approach to management of the safety of the production reactors can be improved

76 FR 6637 - Assumption Buster Workshop: Defense-in-Depth Is a Smart Investment for Cyber Security

Science.gov (United States)

2011-02-07

... the pros and cons of the Defense-in-Depth strategy for cyber security. The workshop will be held March... Technology Research and Development (NITRD) Program. ACTION: Call for participation. FOR FURTHER INFORMATION... notice is issued by the National Coordination Office for the Networking and Information Technology...

Annual report to Congress: Department of Energy activities relating to the Defense Nuclear Facilities Safety Board, Calendar Year 1999

Energy Technology Data Exchange (ETDEWEB)

None

2000-02-01

This is the tenth Annual Report to the Congress describing Department of Energy activities in response to formal recommendations and other interactions with the Defense Nuclear Facilities Safety Board (Board). The Board, an independent executive-branch agency established in 1988, provides advice and recommendations to the Secretary of Energy regarding public health and safety issues at the Department's defense nuclear facilities. The Board also reviews and evaluates the content and implementation of health and safety standards, as well as other requirements, relating to the design, construction, operation, and decommissioning of the Department's defense nuclear facilities. During 1999, Departmental activities resulted in the closure of nine Board recommendations. In addition, the Department has completed all implementation plan milestones associated with three Board recommendations. One new Board recommendation was received and accepted by the Department in 1999, and a new implementation plan is being developed to address this recommendation. The Department has also made significant progress with a number of broad-based initiatives to improve safety. These include expanded implementation of integrated safety management at field sites, opening of a repository for long-term storage of transuranic wastes, and continued progress on stabilizing excess nuclear materials to achieve significant risk reduction.

Internal safety review team at Comanche Peak SES

Energy Technology Data Exchange (ETDEWEB)

Davis, D [Comanche Peak Steam Electric Staion, Texas Utilities, TX (United States)

1997-09-01

The presentations describes the following issues: levels of defense in depth; internal safety review organizations; methods used to perform safety assessment; safety committee review; quality verification; root cause analysis; human performance program; industry operating experience.

Defense-in-depth approach against a beyond design basis event

Energy Technology Data Exchange (ETDEWEB)

Hoang, H., E-mail: Hoa.hoang@ge.com [GE Hitachi Nuclear Energy, 1989 Little Orchard St., 95125 San Jose, California (United States)

2013-10-15

The US industry, with the approval of the Nuclear Regulatory Commission, is promoting an approach to add diverse and flexible mitigation strategies, or Flex, that will increase the defense-in-depth capability for the nuclear power plants in the event of beyond design basis event, such as at the Fukushima Dai-ichi station. The objective of Flex is to establish and indefinite coping capability to prevent damage to the fuel in the core and spent fuel pool, and to maintain the containment function by utilizing installed equipment, on-site portable equipment and pre-staged off-site resources. This capability will address both an extended loss of all Ac power and a loss of ultimate heat sink which could arise following a design basis event with additional failures, and conditions from a beyond design basis event. (author)

Defense-in-depth approach against a beyond design basis event

International Nuclear Information System (INIS)

Hoang, H.

2013-10-01

The US industry, with the approval of the Nuclear Regulatory Commission, is promoting an approach to add diverse and flexible mitigation strategies, or Flex, that will increase the defense-in-depth capability for the nuclear power plants in the event of beyond design basis event, such as at the Fukushima Dai-ichi station. The objective of Flex is to establish and indefinite coping capability to prevent damage to the fuel in the core and spent fuel pool, and to maintain the containment function by utilizing installed equipment, on-site portable equipment and pre-staged off-site resources. This capability will address both an extended loss of all Ac power and a loss of ultimate heat sink which could arise following a design basis event with additional failures, and conditions from a beyond design basis event. (author)

Implementation plan for the Defense Nuclear Facilities Safety Board Recommendation 90-7

International Nuclear Information System (INIS)

Borsheim, G.L.; Cash, R.J.; Dukelow, G.T.

1992-12-01

This document revises the original plan submitted in March 1991 for implementing the recommendations made by the Defense Nuclear Facilities Safety Board in their Recommendation 90-7 to the US Department of Energy. Recommendation 90-7 addresses safety issues of concern for 24 single-shell, high-level radioactive waste tanks containing ferrocyanide compounds at the Hanford Site. The waste in these tanks is a potential safety concern because, under certain conditions involving elevated temperatures and low concentrations of nonparticipating diluents, ferrocyanide compounds in the presence of oxidizing materials can undergo a runaway (propagating) chemical reaction. This document describes those activities underway by the Hanford Site contractor responsible for waste tank safety that address each of the six parts of Defense Nuclear Facilities Safety Board Recommendation 90-7. This document also identifies the progress made on these activities since the beginning of the ferrocyanide safety program in September 1990. Revised schedules for planned activities are also included

Defense against common-mode failures in protection system design

International Nuclear Information System (INIS)

Wyman, R.H.; Johnson, G.L.

1998-01-01

The introduction of digital instrumentation and control into reactor safety systems creates a heightened concern about common-mode failure. This paper discusses the concern and methods of cope with the concern. Common-mode failures have been a 'fact-of-life' in existing systems. The informal introduction of defense-in-depth and diversity (D-in-D and D) - coupled with the fact that hardware common-mode failures are often distributed in time - has allowed systems to deal with past common-mode failures. However, identical software operating in identical redundant systems presents the potential for simultaneous failure. Consequently, the use of digital systems raises the concern about common-mode failure to a new level. A more methodical approach to mitigating common-mode failure is needed to address these concerns. Purposeful introduction of D-in-D and D has been used as a defense against common-mode failure in reactor protection systems. At least two diverse systems are provided to mitigate any potential initiating event. Additionally, diverse displays and controls are provided to allow the operator to monitor plant status and manually initiate engineered safety features. A special form of common-mode failure analysis called 'defense-in-depth and diversity analysis' has been developed to identify possible common-mode failure vulnerabilities in digital systems. An overview of this analysis technique is provided. (author)

Defense against common-mode failures in protection system design

International Nuclear Information System (INIS)

Wyman, R.H.; Johnson, G.L.

1997-01-01

The introduction of digital instrumentation and control into reactor safety systems creates a heightened concern about common-mode failure. This paper discusses the concern and methods to cope with the concern. Common-mode failures have been a ''fact-of-life'' in existing systems. The informal introduction of defense-in-depth and diversity (D-in-D ampersand D)-coupled with the fact that hardware common-mode failures are often distributed in time-has allowed systems to deal with past common-mode failures. However, identical software operating in identical redundant systems presents the potential for simultaneous failure. Consequently, the use of digital systems raises the concern about common-mode failure to a new level. A more methodical approach to mitigating common-mode failure is needed to address these concerns. Purposeful introduction of D-in-D ampersand D has been used as a defense against common-mode failure in reactor protection systems. At least two diverse systems are provided to mitigate any potential initiating event. Additionally, diverse displays and controls are provided to allow the operator to monitor plant status and manually initiate engineered safety features. A special form of conimon-mode failure analysis called ''defense-in-depth and diversity analysis'' has been developed to identify possible conimon-mode failure vulnerabilities in digital systems. An overview of this analysis technique is provided

Synergy in the areas of NPP nuclear safety and nuclear security

International Nuclear Information System (INIS)

Dybach, A.M.; Kuzmyak, I.Ya.; Kukhotskij, A.V.

2013-01-01

The paper considers the question of synergy between nuclear safety and nuclear security. Special attention is paid to identifying interface of the two areas of safety and definition of common principles for nuclear security and nuclear safety measures. The principles of defense in depth, safety culture and graded approach are analyzed in detail.Specific features characteristic of nuclear safety and security are outlined

75 FR 9196 - Letter From Secretary of Energy Accepting Defense Nuclear Facilities Safety Board (Board...

Science.gov (United States)

2010-03-01

... DEPARTMENT OF ENERGY Letter From Secretary of Energy Accepting Defense Nuclear Facilities Safety Board (Board) Recommendation 2009-2 AGENCY: Department of Energy. ACTION: Notice. SUMMARY: The...: The Department of Energy (DOE) acknowledges receipt of Defense Nuclear Facilities Safety Board (Board...

Defence in depth in nuclear safety. INSAG-10. A report by the International Nuclear Safety Advisory Group

International Nuclear Information System (INIS)

1996-01-01

The present report deals with the concept of defence in depth in nuclear and radiation safety, discussing its objectives, strategy, implementation and future development. The report is intended for use by governmental authorities and by the nuclear industry and its supporting organizations. It is intended to stimulate discussion and to promote practical action at all levels to enhance safety. 6 refs, 1 tab

A line of defense approach to fissile material control

International Nuclear Information System (INIS)

Holloway, S.P.; Holloway, N.J.

1995-01-01

A crucial element of the safety policy of the UK Atomic Weapons Establishment (AWE) is that concerned with the safe control of fissile material in order to minimize the potential for unplanned criticality. The principles by which AWE controls fissile material advocate a simple Line of Defense (LOD) approach to assessing criticality-safety related aspects of fissile operations. An LOD assessment provides a measure of the depth of defense available to prevent general types of criticality accident and can be used to demonstrate compliance with the risk-based Basic Safety Limits (BSLs) and Objectives (BSOs) used by the UK Nuclear Installations Inspectorate (NII) to judge the safety of operations in accordance with its Safety Assessment Principles (SAPs) for Nuclear Plants. This paper discusses the LOD concept, the basis of LOD assessment and describes LODs specific to criticality control

Comparison of potential health and safety impacts of different disposal options for defense high-level wastes

International Nuclear Information System (INIS)

Kocher, D.C.; Smith, E.D.; Witherspoon, J.P.

1984-01-01

A comparative assessment has been performed of the potential long- and short-term health and safety impacts of different disposal options for defense high-level wastes. Conservative models and assumptions were used. The assessment suggests that considerations of health and safety will not be significant in choosing among disposal options, primarily because of the need to meet stringent standards in all cases. Rather, the ease and cost of assuring compliance of a particular disposal option with health and safety standards may be a more important factor. 11 references

Safety philosophy for nuclear power plants in egypt

International Nuclear Information System (INIS)

Mervat, S.A.; Hammad, F.H.

1988-01-01

This work establishes the basic principles of a safety philosophy for nuclear power plants in egypt. A number of deterministic requirements stemming the multiple barriers and the defense-in-depth concept are emphasised. other requirements in the areas of siting, operational safety, safety analysis, special issues, and experience feedback are also identified. The role of international cooperation in nuclear safety technology-transfer and nuclear emergencies is highlighted. In addition probabilistic ally based guidelines are set for acceptable risk and dose limits

A defence in depth approach to safety assessment of existing nuclear power plant

International Nuclear Information System (INIS)

Butcher, P.; Holloway, N.J.

1998-01-01

The safety assessment of plant built to earlier standards requires an approach to prioritisation of upgrades that is based on sound engineering and safety principles. The principles of defence in depth are universally accepted and can form the basis of a prioritisation scheme for safety issues, and hence for the upgrading required to address them. The described scheme includes criteria for acceptability and issue prioritisation that are based on the number of lines of defence and the consequences of their failure. They are thus equivalent in concept to risk criteria, but are based on deterministic principles. This scheme has been applied successfully to the RBMK plant at Ignalina in Lithuania, for which a Western-style Safety Analysis Report has recently been produced and reviewed by joint Western and Eastern teams. An extended Safety Improvement Programme (SIP2) has been developed and agreed, based on prioritisations from the defence in depth assessment. (author)

Guidelines on the defense-in-depth and diversity planning and analysis in digital instrumentation and control systems

International Nuclear Information System (INIS)

Cheon, Se Woo; Park, Jong Kyun; Lee, Ki Young; Kwon, Ki Choon; Lee, Jang Soo; Kim, Jang Yeol

2000-08-01

Digital instrumentation and control (I and C) systems are becoming an ever-increasing part in I and C systems of nuclear power plants due to such features such as versatility, flexibility, and reduced sizes. The digital technology introduces a possibility that common-cause or common-mode failures (CCF or CMF) may cause redundant safety systems to fail in such a way that there is loss of safety function. A special form of CMF analysis called 'defense-in-depth and diversity' (D-in-D and D) analysis has been developed to identify possible common-mode failure vulnerabilities and to support a specific licensing action in digital systems. There are two main stages in D-in-D and D activities: both plan and analysis. The purposes of this technical report are i) to review background of D-in-D and D and some of important issues in digital D-in-D and D, ii) to provide guidelines for a vendor to prepare planning and/or analysis documents on D-in-D and D, and iii) to provide guidelines for an evaluator to review applicant's D-in-D and D planning and/or analysis documents, to ensure that the requirements of the D-in-D and D for digital I and C systems are followed. Most of guidelines suggested in this report were based on NUREG/CR-6303 which was published in 1994. The report will be helpful for a vendor to prepare and for an evaluator to review both D-in-D and D planning or analysis documents for digital I and C systems such as the KNGR project

Guidelines on the defense-in-depth and diversity planning and analysis in digital instrumentation and control systems

Energy Technology Data Exchange (ETDEWEB)

Cheon, Se Woo; Park, Jong Kyun; Lee, Ki Young; Kwon, Ki Choon; Lee, Jang Soo; Kim, Jang Yeol

2000-08-01

Digital instrumentation and control (I and C) systems are becoming an ever-increasing part in I and C systems of nuclear power plants due to such features such as versatility, flexibility, and reduced sizes. The digital technology introduces a possibility that common-cause or common-mode failures (CCF or CMF) may cause redundant safety systems to fail in such a way that there is loss of safety function. A special form of CMF analysis called 'defense-in-depth and diversity' (D-in-D and D) analysis has been developed to identify possible common-mode failure vulnerabilities and to support a specific licensing action in digital systems. There are two main stages in D-in-D and D activities: both plan and analysis. The purposes of this technical report are (i) to review background of D-in-D and D and some of important issues in digital D-in-D and D, (ii) to provide guidelines for a vendor to prepare planning and/or analysis documents on D-in-D and D, and (iii) to provide guidelines for an evaluator to review applicant's D-in-D and D planning and/or analysis documents, to ensure that the requirements of the D-in-D and D for digital I and C systems are followed. Most of guidelines suggested in this report were based on NUREG/CR-6303 which was published in 1994. The report will be helpful for a vendor to prepare and for an evaluator to review both D-in-D and D planning or analysis documents for digital I and C systems such as the KNGR project.

Joint probability safety assessment for NPP defense infrastructure against extreme external natural hazards

International Nuclear Information System (INIS)

Guilin, L.; Defu, L.; Huajun, L.; Fengqing, W.; Tao, Z.

2012-01-01

With the increasing tendency of natural hazards, the typhoon, hurricane and tropical Cyclone induced surge, wave, precipitation, flood and wind as extreme external loads menacing Nuclear Power Plants (NPP) in coastal and inland provinces of China. For all of planned, designed And constructed NPP the National Nuclear Safety Administration of China and IAEA recommended Probable Maximum Hurricane /Typhoon/(PMH/T), Probable Maximum Storm Surge (PMSS), Probable Maximum Flood (PMF), Design Basis Flood (DBF) as safety regulations for NPP defense infrastructures. This paper discusses the joint probability analysis of simultaneous occurrence typhoon induced extreme external hazards and compare with IAEA 2006-2009 recommended safety regulation design criteria for some NPP defense infrastructures along China coast. (authors)

Safety significance of ATR passive safety response attributes

International Nuclear Information System (INIS)

Atkinson, S.A.

1990-01-01

The Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory was designed with some passive safety response attributes which contribute to the safety of the facility. The three passive safety attributes being evaluated in the paper are: 1) In-core and in-vessel natural convection cooling, 2) a passive heat sink capability of the ATR primary coolant system (PCS) for the transfer of decay power from the uninsulated piping to the confinement, and 3) gravity feed of emergency coolant makeup. The safety significance of the ATR passive safety response attributes is that the reactor can passively respond to most transients, given a reactor scram, to provide adequate decay power removal and a significant time for operator action should the normal active heat removal systems and their backup systems both fail. The ATR Interim Level 1 Probabilistic Risk Assessment (PRA) models and results were used to evaluate the significance to ATR fuel damage frequency (or probability) of the above three passive response attributes. The results of the evaluation indicate that the first attribute is a major safety characteristic of the ATR. The second attribute has a noticeable but only minor safety significance. The third attribute has no significant influence on the ATR firewater injection system (emergency coolant system)

DOE Defense Program (DP) safety programs. Final report, Task 003

International Nuclear Information System (INIS)

1998-01-01

The overall objective of the work on Task 003 of Subcontract 9-X52-W7423-1 was to provide LANL with support to the DOE Defense Program (DP) Safety Programs. The effort included the identification of appropriate safety requirements, the refinement of a DP-specific Safety Analysis Report (SAR) Format and Content Guide (FCG) and Comprehensive Review Plan (CRP), incorporation of graded approach instructions into the guidance, and the development of a safety analysis methodologies document. All tasks which were assigned under this Task Order were completed. Descriptions of the objectives of each task and effort performed to complete each objective is provided here

An Overview and Evaluation of U.S. SFR Safety Approach

International Nuclear Information System (INIS)

Sofu, Tanju

2013-01-01

Safety Approach: • The traditional approach to demonstrating adequacy of defense-in-depth in a design is deterministic, but a combination of deterministic and probabilistic approaches is increasingly recommended for especially for advanced reactors. – Deterministic approach classifies initiating events by likelihood, while the risk-informed approach introduces a quantified probability estimate. • Risk-informed and performance-based safety approach considers both probability and consequences of events. – Accidents with large consequences are reduced in risk significance by requiring that their probability are acceptably small

Survey of the Diversity and Defense-in-Depth Technologies for Application to NPP Digital I and C Systems

International Nuclear Information System (INIS)

Cheon, S. W.; Kim, J. Y.; Choi, J. G.

2011-09-01

This report reviews the nature of common-cause failures (CCFs) of the digital I and C (instrumentation and control) systems, diversity and defense-in-depth (D3) technologies and those practices in nuclear power plants. The report presents the diversity strategies, which consist of combinations of diversity attributes and their associated criteria. The report also presents assessment of the nature of CCFs and compensating diversity attributes. The diversity usage classification scheme involves three families of strategies: (1) different technologies (Strategies A), (2) different approaches within the same technology (Strategies B), and (3) different architectures within the same technology (Strategies C). The grouping of diversity criteria combinations establishes baseline diversity usage and facilitates a systematic organization of strategic approaches for coping with CCF vulnerabilities. Effectively, these baseline sets of diversity criteria constitute appropriate CCF mitigating strategies for digital safety systems. The strategies represent guidance on acceptable diversity usage and can be applied directly to ensure that CCF vulnerabilities identified through a D3 assessment have been adequately resolved. Additionally, the report presents the framework of diversity usage tables are presented for capturing practices regarding diversity usage

Knowledge-based software design for Defense-in-Depth risk monitor system and application for AP1000

International Nuclear Information System (INIS)

Ma Zhanguo; Yoshikawa, Hidekazu; Yang Ming; Nakagawa, Takashi

2017-01-01

As part of the new risk monitor system, the software for the plant Defense-in-Depth (DiD) risk monitor system was designed based on the state-transition and finite-state machine, and then the knowledge-based software was developed by object-oriented method utilizing the Unified Modeling Language (UML). Currently, there are mainly two functions in the developed plant DiD risk monitor software that are knowledge-base editor which is used to model the system in a hierarchical manner and the interaction simulator that simulates the interactions between the different actors in the model. In this paper, a model for playing its behavior is called an Actor which is modeled at the top level. The passive safety AP1000 power plant was studied and the small-break loss-of-coolant accident (SBLOCA) design basis accident transient is modeled using the plant DiD risk monitor software. Furthermore, the simulation result is shown for the interactions between the actors which are defined in the plant DiD risk monitor system as PLANT actor, OPERATOR actor, and SUPERVISOR actor. This paper shows that it is feasible to model the nuclear power plant knowledge base using the software modeling technique. The software can make the large knowledge base for the nuclear power plant with small effort. (author)

WNP-2 outage safety review methodology

International Nuclear Information System (INIS)

Chiang, Albert; Fu, James

2004-01-01

A practical and versatile method was developed in the flow chart and checklist forms to show the defense-in-depth for various key safety functions of a nuclear power plant during shutdown. Using four different colors (green, yellow, orange, and red) for indication of levels of defense-in-depth is visually impressive, easy to understand, and was adopted by the outage management personnel as a convenient reference tool for maintenance activity planning before the outage, and schedule changes during the outage. This paper describes the method and its application at Washington Public Power Supply System's Nuclear Project 2 (WNP-2). (author)

Method for performing diversity and defense-in-depth analyses of reactor protection systems

International Nuclear Information System (INIS)

Preckshot, G.G.

1994-12-01

The purpose of this NUREG is to describe a method for analyzing computer-based nuclear reactor protection systems that discovers design vulnerabilities to common-mode failure. The potential for common-mode failure has become an important issue as the software content of protection systems has increased. This potential was not present in earlier analog protection systems because it could usually be assumed that common-mode failure, if it did occur, was due to slow processes such as corrosion or premature wear-out. This assumption is no longer true for systems containing software. It is the purpose of the analysis method described here to determine points of a design for which credible common-mode failures are uncompensated either by diversity or defense-in-depth

Safety strategy

International Nuclear Information System (INIS)

Schultheiss, G.F.

1980-01-01

The basis for safety strategy in nuclear industry and especially nuclear power plants is the prevention of radioactivity release inside or outside of the technical installation. Therefore either technical or administrative measures are combined to a general strategy concept. This introduction will explain in more detail the following topics: - basic principles of safety - lines of assurance (LOA) - defense in depth - deterministic and probabilistic methods. This presentation is seen as an introduction to the more detailed discussion following in this course, nevertheless some selected examples will be used to illustrate the aspects of safety strategy development although they might be repeated later on. (orig.)

Annual report to Congress. Department of Energy activities relating to the Defense Nuclear Facilities Safety Board, calendar year 2000

Energy Technology Data Exchange (ETDEWEB)

None

2001-03-01

This Annual Report to the Congress describes the Department of Energy's activities in response to formal recommendations and other interactions with the Defense Nuclear Facilities Safety Board. During 2000, the Department completed its implementation and proposed closure of one Board recommendation and completed all implementation plan milestones associated with two additional Board recommendations. Also in 2000, the Department formally accepted two new Board recommendations and developed implementation plans in response to those recommendations. The Department also made significant progress with a number of broad-based safety initiatives. These include initial implementation of integrated safety management at field sites and within headquarters program offices, issuance of a nuclear safety rule, and continued progress on stabilizing excess nuclear materials to achieve significant risk reduction.

Annual report to Congress. Department of Energy activities relating to the Defense Nuclear Facilities Safety Board, calendar year 2000

International Nuclear Information System (INIS)

2001-01-01

This Annual Report to the Congress describes the Department of Energy's activities in response to formal recommendations and other interactions with the Defense Nuclear Facilities Safety Board. During 2000, the Department completed its implementation and proposed closure of one Board recommendation and completed all implementation plan milestones associated with two additional Board recommendations. Also in 2000, the Department formally accepted two new Board recommendations and developed implementation plans in response to those recommendations. The Department also made significant progress with a number of broad-based safety initiatives. These include initial implementation of integrated safety management at field sites and within headquarters program offices, issuance of a nuclear safety rule, and continued progress on stabilizing excess nuclear materials to achieve significant risk reduction

Safety assurance logic techniques for evaluation of accident prevention and mitigation

International Nuclear Information System (INIS)

McWethy, L.M.; Hagan, J.W.

1976-01-01

Safety assurance methods have been developed and applied in reactor safety assessments of FFTF. These methods promote visibility of the total safety provided by the plant, both in prevention of off-normal or accident conditions as well as provision of various features which terminate conditions within acceptable bounds if such conditions should occur. One of the primary techniques applied in safety assurance is the development of safety assurance diagrams. These diagrams explicitly identify the multiple lines of defense which prevent accident progression. The diagrams graphically demonstrate the defense-in-depth provided by the plant for each postulated occurrence. Lines of defense are shown against ever having an occurrence in the first place; thus giving appropriate emphasis on accident prevention, and visibility to the designer's role in promoting this level of safety. These diagrams, or accident process trees, also show graphically the various paths of postulated accident progression to their logical termination. Evaluation of the importance and strength of each line-of-defense assures fulfillment of the safety objectives of the overall plant system

Quarterly report on Defense Nuclear Facilities Safety Board Recommendation 90-7 for the period ending December 31, 1992

International Nuclear Information System (INIS)

Cash, R.J.; Dukelow, G.T.; Forbes, C.J.

1993-03-01

This is the seventh quarterly report on the progress of activities addressing safety issues associated with Hanford Site high-level radioactive waste tanks that contain ferrocyanide compounds. In the presence of oxidizing materials, such as nitrates or nitrites, ferrocyanide can be made to explode in the laboratory by heating it to high temperatures [above 285 degrees C (545 degrees F)]. In the mid 1950s approximately 140 metric tons of ferrocyanide were added to 24 underground high-level radioactive waste tanks. An implementation plan (Cash 1991) responding to the Defense Nuclear Facilities Safety Board Recommendation 90-7 (FR 1990) was issued in March 1991 describing the activities that were planned and underway to address each of the six parts of Recommendation 90-7. A revision to the original plan was transmitted to US Department of Energy by Westinghouse Hanford Company in December 1992. Milestones completed this quarter are described in this report. Contents of this report include: Introduction; Defense Nuclear Facilities Safety Board Implementation Plan Task Activities (Defense Nuclear Facilities Safety Board Recommendation for enhanced temperature measurement, Recommendation for continuous temperature monitoring, Recommendation for cover gas monitoring, Recommendation for ferrocyanide waste characterization, Recommendation for chemical reaction studies, and Recommendation for emergency response planning); Schedules; and References. All actions recommended by the Defense Nuclear Facilities Safety Board for emergency planning by Hanford Site emergency preparedness organizations have been completed

The in-depth safety assessment (ISA) pilot projects in Ukraine

International Nuclear Information System (INIS)

Kot, C. A.

1998-01-01

Ukraine operates pressurized water reactors of the Soviet-designed type, VVER. All Ukrainian plants are currently operating with annually renewable permits until they update their safety analysis reports (SARs). After approval of the SARS by the Ukrainian Nuclear Regulatory Authority, the plants will be granted longer-term operating licenses. In September 1995, the Nuclear Regulatory Authority and the Government Nuclear Power Coordinating Committee of Ukraine issued a new contents requirement for the safety analysis reports of VVERs in Ukraine. It contains requirements in three major areas: design basis accident (DBA) analysis, probabilistic risk assessment (PRA), and beyond design-basis accident (BDBA) analysis. The DBA requirements are an expanded version of the older SAR requirements. The last two requirements, on PRA and BDBA, are new. The US Department of Energy (USDOE), through the International Nuclear Safety Program (INSP), has initiated an assistance and technology transfer program to Ukraine to assist their nuclear power stations in developing a Western-type technical basis for the new SARS. USDOE sponsored In-Depth Safety Assessments (ISAs) have been initiated at three pilot nuclear reactor units in Ukraine, South Ukraine Unit 1, Zaporizhzhya Unit 5, and Rivne Unit 1. USDOE/INSP have structured the ISA program in such a way as to provide maximum assistance and technology transfer to Ukraine while encouraging and supporting the Ukrainian plants to take the responsibility and initiative and to perform the required assessments

A generalized framework for assessment of safety margins in nuclear power plants

International Nuclear Information System (INIS)

Gavrilas, M.; Youngblood, B.; Prelewicz, D.; Meyer, Jim

2004-01-01

The protection of public health and safety, and the environment from inadvertent releases of radioactive materials from nuclear power plants relies on the implementation of the defense-in-depth strategy. The term defense-in-depth evolved historically, and thus its application has not always been uniform. The use of the term in the context of the U.S. Nuclear Regulatory Commission (NRC) safety philosophy entails the reliance of a nuclear facility on successive compensatory measures in preventing accidents or mitigating damage caused by malfunctions, accidents, or naturally occurring events. The introduction of probabilistic risk analyses with NUREG-74/014 and subsequent evolution in risk assessment techniques, are leading to the implementation of risk informed regulation to ensure the safety of the public and the environment. Risk informed regulation minimizes the likelihood of overlooking potentially significant accident sequences while limiting unnecessary burdens imposed on licensees. The proposed framework merges fundamental elements of safety regulation: defense-in depth, safety margins and probabilistic risk. It formalizes the relationship between probabilistic risk assessment (PRA) methods and data, and deterministic analyses in a manner consistent with NRC's defense-in-depth philosophy. Succinctly put, the likelihood and consequences of accident scenarios are considered simultaneously and quantified by a plant safety metric. The integration of these fundamental elements into a practically applicable safety framework is consistent with the NRC policy statement on use of probabilistic risk assessment methods and the November 2002 Regulatory Guide on risk informed decisions on plant-specific changes to the licensing basis. Safety information resulting from the application of the framework supersedes traditional safety figures of merit. Safety quantifiers, referred herein as safety indices, expand on the qualifier outcomes that currently accompany fault tree

Refinement of nuclear safety education reinforcing technical succession

International Nuclear Information System (INIS)

Yokobori, Seiichi

2008-01-01

In April 2008, Musashi Institute of Technology established another faculty, the Faculty of Nuclear Safety Engineering, to educate students for nuclear engineering to meet the demands of personnel for nuclear business. At this new faculty, students mainly obtain professional knowledge and skills related to nuclear safety issues. This article described refinement of nuclear safety education by reinforcing technical succession topics, such as Rankine cycle, fission, two-phase flow, defense in depth in safety. LOCA/ECCS, seismic effects, reactor maintenance. (T. Tanaka)

A step towards positive safety culture in DAE units

International Nuclear Information System (INIS)

Ramprasad, K.

2016-01-01

Department of Atomic Energy (DAE) has considered safety as its priority, since inception in late 1950s, in all its activities. A belief in safety principles like defense-in depth, diversity, multi-tier review, etc. has laid a long path of success in safety management for decades. Multitude of DAE activities in the past few decades, especially in application of nuclear energy in scientific research, industrial, medical, agriculture and food technologies, often, poses new challenges in safety management. A good safety management system is in place in DAE units to cope up with the challenges of the evolving technologies. An opportunity is taken through this workshop to highlight extra efforts to be taken to inch forward in developing a strong safety culture

Nuclear reactor safety in the USA

International Nuclear Information System (INIS)

Vigil, J.C.

1983-01-01

Nuclear reactor safety in the USA has emphasized a defense-in-depth approach to protecting the public from reactor accidents. This approach was severely tested by the Three Mile Island accident and was found to be effective in safeguarding the public health and safety. However, the economic impact of the TMI accident was very large. Consequently, more attention is now being given to plant protection as well as public-health protection in reactor-safety studies. Sophisticated computer simulations at Los Alamos are making major contributions in this area. In terms of public risk, nuclear power plants compare favorably with other large-scale alternatives to electricity generation. Unfortunately, there is a large gulf between the real risks of nuclear power and the present public perception of these risks

Safety design study of fast breeder reactors in Japan

International Nuclear Information System (INIS)

Miura, M.; Inagaki, T.

1992-01-01

This paper reports on two fast breeder reactor (FBR) concepts, the tank type and the loop type, that have been studied as possible reactor designs to be used for a demonstration FBR (DFBR). The basic principle fo the DFBR design is to ensure plant safety through a defense-in-depth methodology. Improvements in the seismic and thermal stress designs have been attempted for both reactor concepts. The system design study strives to maximize the reliability of the safety-related systems and to rationalize commercialization of the plant

Investment in defense and cost of predator-induced defense along a resource gradient

DEFF Research Database (Denmark)

Steiner, Uli

2007-01-01

An organism's investment in different traits to reduce predation is determined by the fitness benefit of the defense relative to the fitness costs associated with the allocation of time and resources to the defense. Inherent tradeoffs in time and resource allocation should result in differential...... investment in defense along a resource gradient, but competing models predict different patterns of investment. There are currently insufficient empirical data on changes in investment in defensive traits or their costs along resource gradients to differentiate between the competing allocation models....... In this study, I exposed tadpoles to caged predators along a resource gradient in order to estimate investment in defense and costs of defense by assessing predator-induced plasticity. Induced defenses included increased tail depth, reduced feeding, and reduced swimming activity; costs associated...

AP1000{sup R} nuclear power plant safety overview for spent fuel cooling

Energy Technology Data Exchange (ETDEWEB)

Gorgemans, J.; Mulhollem, L.; Glavin, J.; Pfister, A.; Conway, L.; Schulz, T.; Oriani, L.; Cummins, E.; Winters, J. [Westinghouse Electric Company LLC, 1000 Westinghouse Drive, Cranberry Township, PA 16066 (United States)

2012-07-01

The AP1000{sup R} plant is an 1100-MWe class pressurized water reactor with passive safety features and extensive plant simplifications that enhance construction, operation, maintenance, safety and costs. The AP1000 design uses passive features to mitigate design basis accidents. The passive safety systems are designed to function without safety-grade support systems such as AC power, component cooling water, service water or HVAC. Furthermore, these passive features 'fail safe' during a non-LOCA event such that DC power and instrumentation are not required. The AP1000 also has simple, active, defense-in-depth systems to support normal plant operations. These active systems provide the first level of defense against more probable events and they provide investment protection, reduce the demands on the passive features and support the probabilistic risk assessment. The AP1000 passive safety approach allows the plant to achieve and maintain safe shutdown in case of an accident for 72 hours without operator action, meeting the expectations provided in the U.S. Utility Requirement Document and the European Utility Requirements for passive plants. Limited operator actions are required to maintain safe conditions in the spent fuel pool via passive means. In line with the AP1000 approach to safety described above, the AP1000 plant design features multiple, diverse lines of defense to ensure spent fuel cooling can be maintained for design-basis events and beyond design-basis accidents. During normal and abnormal conditions, defense-in-depth and other systems provide highly reliable spent fuel pool cooling. They rely on off-site AC power or the on-site standby diesel generators. For unlikely design basis events with an extended loss of AC power (i.e., station blackout) or loss of heat sink or both, spent fuel cooling can still be provided indefinitely: - Passive systems, requiring minimal or no operator actions, are sufficient for at least 72 hours under all

CNS Orientations, Safety Objectives and Implementation of the Defence in Depth Concept

Energy Technology Data Exchange (ETDEWEB)

Lacoste, A.C., E-mail: Andre-Claude.LACOSTE@asn.fr [Autorité de Sureté Nucléaire, Montrouge (France)

2014-10-15

Full text: The 6th Review Meeting of the Convention on Nuclear Safety (CNS) is convened in Vienna next year for two weeks from Monday March 24{sup th} to Friday April 4{sup th} 2014. The consequences and the lessons learnt from the accident that occurred at the Fukushima Daiichi nuclear power plant will be a major issue. The 2nd Extraordinary Meeting of the CNS in August 2012 was totally devoted to the Fukushima Daiichi accident. One of its main conclusions was Conclusion 17 included in the summary report which says: ''Nuclear power plants should be designed, constructed and operated with the objectives of preventing accidents and, should an accident occur, mitigating its effects and avoiding off-site contamination. The Contracting Parties also noted that regulatory authorities should ensure that these objectives are applied in order to identify and implement appropriate safety improvements at existing plants''. The wording of the sentences of Conclusion 17 dedicated, the first one to new built reactors, the second one to existing plants, can be improved and clarified. But obviously the issue of the off-site consequences of an accident is fundamental. So the in-depth question comes: what can and should be done to achieve these safety objectives? And in particular how to improve the definition and then the implementation of the Defence in Depth Concept? From my point of view, this is clearly the main issue of this Conference. (author)

A new approach to determine the environmental qualification requirements for the safety related equipment

International Nuclear Information System (INIS)

Hasnaoui, C.; Parent, G.

2000-01-01

The objective of the environmental qualification of safety related equipment is to ensure that the plant defense-in-depth is not compromised by common mode failures following design basis accidents with a harsh environment. A new approach based on safety functions has been developed to determine what safety-related equipment is required to function during and after a design basis accident, as well as their environmental qualification requirements. The main feature of this approach is to use auxiliary safety functions established from safety requirements as credited in the safety analyses. This approach is undertaken in three steps: identification of the auxiliary safety functions of each main safety function; determination of the main equipment groups required for each auxiliary safety function; and review of the safety analyses for design basis accidents in order to determine the credited auxiliary safety functions and their mission times for each accident scenario. Some of the benefits of the proposed approach for the determination of the safety environmental qualification requirements are: a systematic approach for the review of safety analyses based on a safety function check list, and the insurance, with the availability of the safety functions, that Gentilly-2 defense-in-depth would not be compromised by design basis accidents with a harsh environment. (author)

Lessons learned - development of the tritium facilities 5480.23 safety analysis report and technical safety requirements

International Nuclear Information System (INIS)

Cappucci, A.J. Jr.; Bowman, M.E.; Goff, L.

1997-01-01

A review was performed which identified open-quotes Lessons Learnedclose quotes from the development of the 5480.23 Tritium Safety Analysis Report (SAR) and the Technical Safety Requirements (TSR) for the Tritium Facilities (TF). The open-quotes Lessons Learnedclose quotes were based on an evaluation of the use of the SRS procedures, processes, and work practices which contributed to the success or lack thereof. This review also identified recommendations and suggestions for improving the development of SARs and TSRs at SRS. The 5480.23 SAR describes the site for the TF, the various process systems in the process buildings, a complete hazards and accident analysis of the most significant hazards affecting the nearby offsite population, and the selection of safety systems, structures, and components to protect both the public and site workers. It also provides descriptions of important programs and processes which add defense in depth to public and worker protection

SRP reactor safety evolution

International Nuclear Information System (INIS)

Rankin, D.B.

1984-01-01

The Savannah River Plant reactors have operated for over 100 reactor years without an incident of significant consequence to on or off-site personnel. The reactor safety posture incorporates a conservative, failure-tolerant design; extensive administrative controls carried out through detailed operating and emergency written procedures; and multiple engineered safety systems backed by comprehensive safety analyses, adapting through the years as operating experience, changes in reactor operational modes, equipment modernization, and experience in the nuclear power industry suggested. Independent technical reviews and audits as well as a strong organizational structure also contribute to the defense-in-depth safety posture. A complete review of safety history would discuss all of the above contributors and the interplay of roles. This report, however, is limited to evolution of the engineered safety features and some of the supporting analyses. The discussion of safety history is divided into finite periods of operating history for preservation of historical perspective and ease of understanding by the reader. Programs in progress are also included. The accident at Three Mile Island was assessed for its safety implications to SRP operation. Resulting recommendations and their current status are discussed separately at the end of the report. 16 refs., 3 figs

Rethinking Defensive Information Warfare

National Research Council Canada - National Science Library

French, Geoffrey S

2004-01-01

.... This paper examines defensive tactics and strategies from the German defense in depth that emerged from World War I to the American Active Defense that developed in the Cold War and proposes a new mindset for DIW that draws on these operational concepts from military history.

Experimental evidence concerning the significant information depth of electron backscatter diffraction (EBSD)

Energy Technology Data Exchange (ETDEWEB)

Wisniewski, Wolfgang, E-mail: wolfgang.w@uni-jena.de [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Saager, Stefan [Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, Winterbergstraße 28, 01277 Dresden (Germany); Böbenroth, Andrea [Fraunhofer Institute for the Microstructure of Materials and Systems IMWS, Walter-Huelse-Straße 1, 06120 Halle (Saale) (Germany); Rüssel, Christian [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

2017-02-15

Experiments concerning the information depth of electron backscatter diffraction (EBSD) are performed on samples featuring an amorphous wedge on a crystalline substrate and a crystalline wedge on an amorphous substrate. The effects of the acceleration voltage and exemplary software settings on the ability to measure through an amorphous layer are presented. Changes in the EBSD-signal could be detected through a ≈142 nm thick layer of amorphous Si while orientation measurements could be performed through a ≈116 nm thick layer when using a voltage of 30 kV. The complexity of the information depth significant to a given EBSD-pattern and the multiple parameters influencing it are discussed. It is suggested that a “core information depth” is significant to high quality patterns while a larger “maximum information depth” becomes relevant when the pattern quality decreases or the sample is inhomogeneous within the information volume, i.e. in the form of partially crystalline materials or crystal layers in the nm scale. - Highlights: • Experimental evidence of the significant information depth of EBSD is presented. • Effects of the voltage and exemplary software settings are discussed. • Dependence of the significant information depth on the pattern quality is proposed. • The information depth may reach up to 142 nm in Si when using a voltage of 30 kV. • The information depth depends on the available technology.

User requirements in the area of safety of innovative nuclear reactors and fuel cycle installations

International Nuclear Information System (INIS)

Kuczera, B.; Juhn, P.E.; Fukuda, K.; )

2002-01-01

Full text: Against the background of already existing IAEA and INSAC publications in the area of safety, in the framework of the International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) a set of user requirements for the safety of future nuclear installations has been established. Five top-level requirements are expected to apply to any type of innovative design. They should foster an increased level of safety that is transparent to and fully accepted by the general public. The approach to future reactor safety includes two complementary strategies: increased emphasis on inherent safety characteristics and enhancement of defense in depth. As compared to existing plants, the effectiveness of preventing measures should be highly enhanced, resulting in fewer mitigation measures. The targets and possible approaches of each of the five levels of defense developed for innovative reactor designs are outlined in the paper

Safety significance of ATR [Advanced Test Reactor] passive safety response attributes

International Nuclear Information System (INIS)

Atkinson, S.A.

1989-01-01

The Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory was designed with some passive safety response attributes which contribute to the safety posture of the facility. The three passive safety attributes being evaluated in the paper are: (1) In-core and in-vessel natural convection cooling, (2) a passive heat sink capability of the ATR primary coolant system (PCS) for the transfer of decay power from the uninsulated piping to the confinement, and (3) gravity feed of emergency coolant makeup. The safety significance of the ATR passive safety response attributes is that the reactor can passively respond for most transients, given a reactor scram, to provide adequate decay power removal and a significant time for operator action should the normal active heat removal systems and their backup systems both fail. The ATR Interim Level 1 Probabilistic Risk Assessment (PRA) model ands results were used to evaluate the significance to ATR fuel damage frequency (or probability) of the above three passive response attributes. The results of the evaluation indicate that the first attribute is a major safety characteristic of the ATR. The second attribute has a noticeable but only minor safety significance. The third attribute has no significant influence on the ATR Level 1 PRA because of the diversity and redundancy of the ATR firewater injection system (emergency coolant system). 8 refs., 4 figs., 1 tab

76 FR 14590 - Defense Federal Acquisition Regulation Supplement; Safety of Facilities, Infrastructure, and...

Science.gov (United States)

2011-03-17

... makes it unlikely that a small business could afford to sustain the infrastructure required to perform...-AG73 Defense Federal Acquisition Regulation Supplement; Safety of Facilities, Infrastructure, and... facilities, infrastructure, and equipment that are intended for use by military or civilian personnel of the...

Strengthening safety of nuclear power by learning lessons from the accident at TEPCO's Fukushima-Daiichi Nuclear Power Plant

International Nuclear Information System (INIS)

Omoto, Akira

2011-01-01

The paper first discusses ongoing onsite stabilization activities at Fukushima-Daiichi NPP and a plan for onsite and offsite remedial actions including decontamination and defueling. Four key lessons learned (LL) are raised; safety regulation and safety culture, workable/executable severe accident management procedure, crisis management and design. Global actions for strengthening safety in post-Fukushima era would be built around the IAEA action plan, under recognition of national responsibility. For specific country and plant, a combination of the following may help; a) overall assessment of safety and reflection of Fukushima LL in the light of principles in INSAG-12, b) specific plant assessment of risks from internal, external and security-related events for identifying vulnerabilities and continuous safety improvement, and c) international peer review for comprehensiveness, objectivity and confidence building. In this context, the followings could be worth receiving attention; a) to revisit defense-in-depth, while utilizing risk information, for its completeness and effectiveness (especially, strengthened defense against environmental contamination by effective combination of provisions and management as well as attentiveness and careful attitude towards uncertainties across all layers of defense-in-depth), b) to restore public confidence, c) to cooperate for safety infrastructure in newcomers, d) to build internationally harmonized and cooperative scheme for liability. (author)

Study on the KALIMER safety approach

International Nuclear Information System (INIS)

Kim, Eui Kwang; Han, Do Hee; Kim, Young Cheol.

1997-01-01

This study describes KALIMER's safety approach, how to establish the safety criteria and temperature limit, how to define safety evaluation events, and some safety research and development needs items. It is recommended that the KALIMER's approach to safety use seven levels of safety design and a defense-in-depth design approach with particular emphasis on inherent passive features. In order to establish as set DBEs for KALIMER safety evaluation, the procedure is explained how to define safety evaluation events. Final selection is to be determined later with the final establishment of design concepts. On the basis of preliminary studies and evaluation of the plant safety related areas, the KALIMER and PRISM have following three main difference that may require special research and development for KALIMER. (author). 7 refs., 6 tabs., 6 figs

Application of the Defense-in-Depth Concept in the Projects of New-Generation NPPs Equipped with VVER Reactors

Energy Technology Data Exchange (ETDEWEB)

Shvyryaev, Yu. V.; Morozov, V. B.; Kuchumov, A.Yu., E-mail: morozov@aep.ru [JSC Atomenergoproekt, Moscow (Russian Federation)

2014-10-15

The projects of new-generation NPPs equipped with VVER reactors are developed as projects the safety level of which is superior to that of NPPs that are currently in operation. The main design solutions adopted for implementing the defence-in-depth (DiD) concept in the projects of new-generation NPPs equipped with VVER reactors are briefly characterized in the paper. (author)

NPP Temelin safety analysis reports and PSA status

International Nuclear Information System (INIS)

Mlady, O.

1999-01-01

To enhance the safety level of Temelin NPP, recommendations of the international reviews were implemented into the design as well as into organization of the plant construction and preparation for operation. The safety assessment of these design changes has been integrated and reflected in the Safety Analysis Reports, which follow the internationally accepted guidelines. All safety analyses within Safety Analysis Reports were repeated carefully considering technical improvements and replacements to complement preliminary safety documentation. These analyses were performed by advanced western computer codes to the depth and in the structure required by western standards. The Temelin NPP followed a systematic approach in the functional design of the Reactor Protection System and related safety analyses. Modifications of reactor protection system increase defense in depth and facilitate demonstrating that LOCA and radiological limits are met for non-LOCA events. The rigorous safety analysis methodology provides assurance that LOCA and radiological limits are met. Established and accepted safety analysis methodology and accepted criteria were applied to Temelin NPP meeting US NRC and Czech Republic requirements. IAEA guidelines and recommendations

Reinforcing Defence in Depth: A Practical Systemic Approach

International Nuclear Information System (INIS)

Watts, G.; Misak, J.

2016-01-01

The concept of defence in depth for ensuring nuclear safety of nuclear installations is often oversimplified and interpreted as a set of physical barriers, whose integrity is ensured by safety provisions in the form of the plant systems implemented independently at various levels of defence. However, the provisions established at each level of defence should in general terms include not only hardware components (active and passive systems), but more comprehensively, also inherent safety characteristics, safety margins, operating procedures and guidelines, quality assurance, safety culture, staff training, and many other organizational measures as parts of management of safety. Many of the above mentioned provisions belong to the category of human and organizational factors. While various hardware components are typically specific for different levels of defence, human and organizational factors may have an impact on several levels of defence. These factors are associated with large uncertainties and can result in latent weaknesses. Their implementation can negatively affect several levels of defence at the same time. The proposed paper will underline the need for a more comprehensive view of the defence in depth concept in order to provide a practical and effective tool for a systemic approach to safety. The paper will consist of two main parts. The first part will introduce a screening method developed by the IAEA as a tool for facilitating the assessment of the comprehensiveness of defence in depth. The method uses screening of safety provisions at five levels of defence to ensure integrity of the physical barriers and achievement of safety objectives at each level of defence. The second part of the paper will focus on human and organizational factors considered as provisions for reliable performance of safety functions. It will explain the significant shift in the demands on the human system between levels 3 and 4 of the defence in depth framework, and will

Defence in depth in nuclear safety

International Nuclear Information System (INIS)

Jayakumar, J.S.

2016-01-01

Nuclear energy is clean and can prevent global warming and hence it has a lot of importance in the current world. In order for the safe and reliable operation of the NPP, a defence in depth concept has been practised, so that even one level of protection fails the subsequent one will contain the hazardous situation. Various levels, both from consideration of the physical barriers and implementation are described in this paper. Three major accidents happened in nuclear reactors are analysed from the defence in depth concept and shortcomings are discussed. (author)

Safety design

International Nuclear Information System (INIS)

Kunitomi, Kazuhiko; Shiozawa, Shusaku

2004-01-01

JAERI established the safety design philosophy of the HTTR based on that of current reactors such as LWR in Japan, considering inherent safety features of the HTTR. The strategy of defense in depth was implemented so that the safety engineering functions such as control of reactivity, removal of residual heat and confinement of fission products shall be well performed to ensure safety. However, unlike the LWR, the inherent design features of the high-temperature gas-cooled reactor (HTGR) enables the HTTR meet stringent regulatory criteria without much dependence on active safety systems. On the other hand, the safety in an accident typical to the HTGR such as the depressurization accident initiated by a primary pipe rupture shall be ensured. The safety design philosophy of the HTTR considers these unique features appropriately and is expected to be the basis for future Japanese HTGRs. This paper describes the safety design philosophy and safety evaluation procedure of the HTTR especially focusing on unique considerations to the HTTR. Also, experiences obtained from an HTTR safety review and R and D needs for establishing the safety philosophy for the future HTGRs are reported

Categorization of safety related motor operated valve safety significance for Ulchin Unit 3

International Nuclear Information System (INIS)

Kang, D. I.; Kim, K. Y.

2002-03-01

We performed a categorization of safety related Motor Operated Valve (MOV) safety significance for Ulchin Unit 3. The safety evaluation of MOV of domestic nuclear power plants affects the generic data used for the quantification of MOV common cause failure ( CCF) events in Ulchin Units 3 PSA. Therefore, in this study, we re-estimated the MGL(Multiple Greek Letter) parameter used for the evaluation of MOV CCF probabilities in Ulchin Units 3 Probabilistic Safety Assessment (PSA) and performed a classification of the MOV safety significance. The re-estimation results of the MGL parameter show that its value is decreased by 30% compared with the current value in Ulchin Unit 3 PSA. The categorization results of MOV safety significance using the changed value of MGL parameter shows that the number of HSSCs(High Safety Significant Components) is decreased by 54.5% compared with those using the current value of it in Ulchin Units 3 PSA

Insight and Lessons Learned on Safety Culture from Analysis of Inspection Findings and Events

International Nuclear Information System (INIS)

Kim, J.T.; Jung, S.J.; Choi, Y.S.

2016-01-01

Safety culture has been a main subject of scrutiny in major accidents of modern complex technologies. The Fukushima accident also plausibly has its root cause deep into weak safety culture. After the Fukushima accident in Japan 2011, many critics have searched for cultural factors that caused the unacceptable negligence pervaded in Japan’s nuclear society. Renewed emphasis has also been placed on rebuilding strong safety culture by operators, regulators, and relevant institutions worldwide. Significant progress has been made in approach to safety culture and this led to a new perspective different from the existing normative assessment method both in operators and regulatory side. Regulatory expectations and oversight of them are based on such a new holistic concept for human, organizational and cultural elements to maintain and strengthen the integrity of defense in depth and consequently nuclear safety.

Light Water Reactor Sustainability Program: Risk-Informed Safety Margins Characterization (RISMC) Pathway Technical Program Plan

International Nuclear Information System (INIS)

Smith, Curtis; Rabiti, Cristian; Martineau, Richard; Szilard, Ronaldo

2016-01-01

Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly ''over-design'' portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as ''safety margin.'' Historically, specific safety margin provisions have been formulated, primarily based on ''engineering judgment.''

Problems of probabilistic safety assessment after Fukushima Daiichi nuclear power plant accident

International Nuclear Information System (INIS)

Sugiyama, Naoki

2011-01-01

Probabilistic safety assessment (PSA) methodology to assure nuclear safety is had great expectations of lessons learned from Fukushima Daiichi nuclear power plant (NPP) accident and on the other hand this accident made actualized technical problems of PSA. Effectiveness of current PSA methodology for risk assessment was confirmed by comparing the accident development with accident scenario of PSA and equipment failure rate. From a viewpoint of nuclear safety objective and defense in depth approach of IAEA, technical problems of PSA were (1) extension of PSA for spent fuel pool and waste disposal system as well as level 3PSA for broader environmental contamination and (2) overlapping of accident scenario of plural unit site, balance of high quality plant management and preceding negation, treatment of uncertainty of external events, severe accident measure and human reliability analysis and reflection of disaster prevention capability to level 3PSA. In order to upgrade PSA technology, six proposals were described for nuclear safety and defense in depth, comprehensive evaluation scope and catch-up of latest technology, necessity of strategic preparation of PSA standard, human resources fostering and risk communication. (T. Tanaka)

A Review on Internet of Things for Defense and Public Safety

Science.gov (United States)

Fraga-Lamas, Paula; Fernández-Caramés, Tiago M.; Suárez-Albela, Manuel; Castedo, Luis; González-López, Miguel

2016-01-01

The Internet of Things (IoT) is undeniably transforming the way that organizations communicate and organize everyday businesses and industrial procedures. Its adoption has proven well suited for sectors that manage a large number of assets and coordinate complex and distributed processes. This survey analyzes the great potential for applying IoT technologies (i.e., data-driven applications or embedded automation and intelligent adaptive systems) to revolutionize modern warfare and provide benefits similar to those in industry. It identifies scenarios where Defense and Public Safety (PS) could leverage better commercial IoT capabilities to deliver greater survivability to the warfighter or first responders, while reducing costs and increasing operation efficiency and effectiveness. This article reviews the main tactical requirements and the architecture, examining gaps and shortcomings in existing IoT systems across the military field and mission-critical scenarios. The review characterizes the open challenges for a broad deployment and presents a research roadmap for enabling an affordable IoT for defense and PS. PMID:27782052

Assessment of defence in depth for nuclear power plants

International Nuclear Information System (INIS)

2005-01-01

Defence in depth is a comprehensive approach to safety that has been developed by nuclear power experts to ensure with high confidence that the public and the environment are protected from any hazards posed by the use of nuclear power for the generation of electricity. The concepts of defence in depth and safety culture have served the nuclear power industry well as a basic philosophy for the safe design and operation of nuclear power plants. Properly applied, defence in depth ensures that no single human error or equipment failure at one level of defence, nor even a combination of failures at more than one level of defence, propagates to jeopardize defence in depth at the subsequent level or leads to harm to the public or the environment. The importance of the concept of defence in depth is underlined in IAEA Safety Standards, in particular in the requirements set forth in the Safety Standards: Safety of Nuclear Power Plants: Design (NS-R-1) and Safety Assessment and Verification for Nuclear Power Plants (NS-G-1.2). A specific report, Defence in Depth in Nuclear Safety (INSAG-10), describes the objectives, strategy, implementation and future development in the area of defence in depth in nuclear and radiation safety. In the report Basic Safety Principles for Nuclear Power Plants (INSAG-12), defence in depth is recognized as one of the fundamental safety principles that underlie the safety of nuclear power plants. In consonance with those high level publications, this Safety Report provides more specific technical information on the implementation of this concept in the siting, design, construction and operation of nuclear power plants. It describes a method for comprehensive and balanced review of the provisions required for implementing defence in depth in existing plants. This publication is intended to provide guidance primarily for the self-assessment by plant operators of the comprehensiveness and quality of defence in depth provisions. It can be used

Design concepts and safety concerns of the small and medium size reactors (SMR)

International Nuclear Information System (INIS)

Seul, Kwang Won; Lee, Jae Hun; Kim, Hho Jung

1998-01-01

The small and medium size reactors (SMR) and interface facilities such as desalination plant are expected to be located near the population area because of restrictions in transporting the plant products such as fresh water to long distance area. To protect the public around the plant facility from the possible release of radioactive materials, the design development of the SMR is focusing on an enhancement of the safety and reliability as well as the economics. In this study, the major safety concepts of the SMR designs significantly different from the current PWR designs are investigated and the safety concerns applicable to the integrated SMR design of Korea (called SMART), were identified. Those safety issues include the use of proven technology, application of strengthening defense in depth, event categorization and selection, simplification of emergency planning, determination of accident source terms and so on. The efforts to resolve the safety concerns in the design stage will provide an improvement of the safety of the SMART design

Light Water Reactor Sustainability Program Risk-Informed Safety Margins Characterization (RISMC) PathwayTechnical Program Plan

Energy Technology Data Exchange (ETDEWEB)

Curtis Smith; Cristian Rabiti; Richard Martineau

2012-11-01

Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated, primarily based on “engineering judgment.”

Light Water Reactor Sustainability Program: Risk-Informed Safety Margins Characterization (RISMC) Pathway Technical Program Plan

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Szilard, Ronaldo [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-09-01

Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). As the current Light Water Reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of Systems, Structures, and Components (SSCs) degradations or failures that initiate safety-significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated, primarily based on “engineering judgment.”

Safety tests file

International Nuclear Information System (INIS)

2011-01-01

The design and operation of nuclear power plants is governed by strict and clearly defined regulations designed to ensure their safety in all circumstances. Since the first nuclear reactors were commissioned, the basic safety principles and the corresponding practical requirements have constantly evolved and been enhanced, benefiting from operating experience feedback from reactors around the world (about 500 production reactors currently in service). Reactor safety has from the outset been built around the 'defense in depth' concept, which aims to prevent melting of the core and radioactive releases into the environment. It can be summarized as follows: over and above all the measures taken to prevent accidents, the principle that accidents do occur has to be accepted. We then assess their consequences and take steps to contain them at the level of severity at which they occur. (authors)

Using in-depth investigations to identify transportation safety issues for wheelchair-seated occupants of motor vehicles.

Science.gov (United States)

Schneider, Lawrence W; Klinich, Kathleen D; Moore, Jamie L; MacWilliams, Joel B

2010-04-01

In-depth investigations of motor-vehicle crashes involve detailed inspection, measurement, and photodocumentation of vehicle exterior and interior damage, evidence of belt-restraint use, and evidence of occupant contacts with the vehicle interior. Results of in-depth investigations thereby provide the most objective way to identify current and emerging injury problems and issues in occupant safety and crash protection, and provide important feedback on the real-world performance of the latest restraint-system and vehicle crashworthiness technologies. To provide an objective understanding of real-world transportation safety issues for wheelchair-seated travelers, the University of Michigan Transportation Research Institute (UMTRI) has been conducting and assembling data from in-depth investigations of motor-vehicle crashes and non-crash adverse moving-vehicle incidents, such as emergency vehicle braking, turning, and swerving, in which there was at least one vehicle occupant sitting in a wheelchair. The results of 39 investigations involving 42 wheelchair-seated occupants have been assembled and entered into a wheelchair-occupant crash/injury database. In addition, a biomechanical analysis of each case has been performed to identify key safety issues for wheelchair-seated travelers. The wheelchairs of 34 of the 42 occupants who were seated in wheelchairs while traveling in motor vehicles were effectively secured by either a four-point, strap-type tiedown system or a docking securement device, and all but one of these properly secured wheelchairs remained in place during the crash or non-collision event. However, 30 of the 42 occupants were improperly restrained, either because of non-use or incomplete use of available belt restraints, or because the belt restraints were improperly positioned on the occupant's body. Twenty-six of the 42 occupants sustained significant injuries and 10 of these occupants died as a direct result of injuries sustained, or from

A Review on Internet of Things for Defense and Public Safety

Directory of Open Access Journals (Sweden)

Paula Fraga-Lamas

2016-10-01

Full Text Available The Internet of Things (IoT is undeniably transforming the way that organizations communicate and organize everyday businesses and industrial procedures. Its adoption has proven well suited for sectors that manage a large number of assets and coordinate complex and distributed processes. This survey analyzes the great potential for applying IoT technologies (i.e., data-driven applications or embedded automation and intelligent adaptive systems to revolutionize modern warfare and provide benefits similar to those in industry. It identifies scenarios where Defense and Public Safety (PS could leverage better commercial IoT capabilities to deliver greater survivability to the warfighter or first responders, while reducing costs and increasing operation efficiency and effectiveness. This article reviews the main tactical requirements and the architecture, examining gaps and shortcomings in existing IoT systems across the military field and mission-critical scenarios. The review characterizes the open challenges for a broad deployment and presents a research roadmap for enabling an affordable IoT for defense and PS.

A Review on Internet of Things for Defense and Public Safety.

Science.gov (United States)

Fraga-Lamas, Paula; Fernández-Caramés, Tiago M; Suárez-Albela, Manuel; Castedo, Luis; González-López, Miguel

2016-10-05

The Internet of Things (IoT) is undeniably transforming the way that organizations communicate and organize everyday businesses and industrial procedures. Its adoption has proven well suited for sectors that manage a large number of assets and coordinate complex and distributed processes. This survey analyzes the great potential for applying IoT technologies (i.e., data-driven applications or embedded automation and intelligent adaptive systems) to revolutionize modern warfare and provide benefits similar to those in industry. It identifies scenarios where Defense and Public Safety (PS) could leverage better commercial IoT capabilities to deliver greater survivability to the warfighter or first responders, while reducing costs and increasing operation efficiency and effectiveness. This article reviews the main tactical requirements and the architecture, examining gaps and shortcomings in existing IoT systems across the military field and mission-critical scenarios. The review characterizes the open challenges for a broad deployment and presents a research roadmap for enabling an affordable IoT for defense and PS.

Nuclear safety

International Nuclear Information System (INIS)

1991-02-01

This book reviews the accomplishments, operations, and problems faced by the defense Nuclear Facilities Safety Board. Specifically, it discusses the recommendations that the Safety Board made to improve safety and health conditions at the Department of Energy's defense nuclear facilities, problems the Safety Board has encountered in hiring technical staff, and management problems that could affect the Safety Board's independence and credibility

Regulatory Expectations for Safety Culture

Energy Technology Data Exchange (ETDEWEB)

Jung, Su Jin; Oh, Jang Jin; Choi, Young Sung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2014-05-15

The oversight of licensee's safety culture becomes an important issue that attracts great public and political concerns recently in Korea. Beginning from the intended violation of rules, a series of corruptions, documents forgery and disclosure of wrong-doings made the public think that the whole mindset of nuclear workers has been inadequate. Thus, they are demanding that safety culture shall be improved and that regulatory body shall play more roles and responsibilities for the improvements and oversight for them. This paper introduces, as an effort of regulatory side, recent changes in the role of regulators in safety culture, regulatory expectations on the desired status of licensee's safety culture, the pilot inspection program for safety culture and research activity for the development of oversight system. After the Fukushima accident in Japan 2011, many critics has searched for cultural factors that caused the unacceptable negligence pervaded in Japan nuclear society and the renewed emphasis has been placed on rebuilding safety culture by operators, regulators, and relevant institutions globally. Significant progress has been made in how to approach safety culture and led to a new perspective different from the existing normative assessment method both in operators and regulatory side. Regulatory expectations and oversight of them are based on such a new holistic concept for human, organizational and cultural elements to maintain and strengthen the integrity of defense in depth and consequently nuclear safety.

Regulatory Expectations for Safety Culture

International Nuclear Information System (INIS)

Jung, Su Jin; Oh, Jang Jin; Choi, Young Sung

2014-01-01

The oversight of licensee's safety culture becomes an important issue that attracts great public and political concerns recently in Korea. Beginning from the intended violation of rules, a series of corruptions, documents forgery and disclosure of wrong-doings made the public think that the whole mindset of nuclear workers has been inadequate. Thus, they are demanding that safety culture shall be improved and that regulatory body shall play more roles and responsibilities for the improvements and oversight for them. This paper introduces, as an effort of regulatory side, recent changes in the role of regulators in safety culture, regulatory expectations on the desired status of licensee's safety culture, the pilot inspection program for safety culture and research activity for the development of oversight system. After the Fukushima accident in Japan 2011, many critics has searched for cultural factors that caused the unacceptable negligence pervaded in Japan nuclear society and the renewed emphasis has been placed on rebuilding safety culture by operators, regulators, and relevant institutions globally. Significant progress has been made in how to approach safety culture and led to a new perspective different from the existing normative assessment method both in operators and regulatory side. Regulatory expectations and oversight of them are based on such a new holistic concept for human, organizational and cultural elements to maintain and strengthen the integrity of defense in depth and consequently nuclear safety

Analysis Method of Common Cause Failure on Non-safety Digital Control System

Energy Technology Data Exchange (ETDEWEB)

Kim, Yun Goo; Oh, Eun Gse [KHNP, Daejeon (Korea, Republic of)

2014-08-15

The effects of common cause failure on safety digital instrumentation and control system had been considered in defense in depth analysis with safety analysis method. However, the effects of common cause failure on non-safety digital instrumentation and control system also should be evaluated. The common cause failure can be included in credible failure on the non-safety system. In the I and C architecture of nuclear power plant, many design feature has been applied for the functional integrity of control system. One of that is segmentation. Segmentation defenses the propagation of faults in the I and C architecture. Some of effects from common cause failure also can be limited by segmentation. Therefore, in this paper there are two type of failure mode, one is failures in one control group which is segmented, and the other is failures in multiple control group because that the segmentation cannot defense all effects from common cause failure. For each type, the worst failure scenario is needed to be determined, so the analysis method has been proposed in this paper. The evaluation can be qualitative when there is sufficient justification that the effects are bounded in previous safety analysis. When it is not bounded in previous safety analysis, additional analysis should be done with conservative assumptions method of previous safety analysis or best estimation method with realistic assumptions.

Defense in Depth Added to Malicious Activities Simulation Tools (MAST)

Science.gov (United States)

2015-09-01

5 a. Triple Data Encryption Standard (3DES)..............................13 b. Advanced Encryption Standard ( AES ...10 Figure 4. DES Encryption , from [5] ................................................................................12 Figure 5. AES Encryption ...Associated Data AES Advanced Encryption System CBC Cipher Block Chaining DES Data Encryption Standard DOD Department of Defense DSA Digital Signature

Nuclear Safety R&D for the Knowledge-Based Implementation of Defence in Depth

Energy Technology Data Exchange (ETDEWEB)

Baek, W-P., E-mail: wpbaek@kaeri.re.kr [Korea Atomic Energy Research Institute (KAERI), Department of Nuclear Safety Research, Yuseong-gu, Daejeon (Korea, Republic of)

2014-10-15

Assuring a high level of safety is a pre-requisite for the development and utilization of nuclear technology. The most fundamental approach for nuclear power plant (NPP) safety is “defence in depth (DiD),” which is a combination of multiple physical barriers and multiple (generally 5) levels of protection, with the aim of accident prevention and mitigation. NPPs around the world have shown excellent safety records for over 14,500 cumulative reactor years, compared with other electricity sources, by properly implementing DiD. However, the occurrence and severe consequences of the Fukushima accident have provoked controversy on the completeness of the DiD concept. There have been active discussions on DiD with respect to the Fukushima accident. A general consensus has been arrived that the concept of DiD is still valid but its implementation was incomplete for the Fukushima NPP. Had DiD been properly implemented during the design, construction and operation, much better provisioning against the extreme earthquake and tsunami would have been available and the accident consequences would not have been so disastrous.

Software safety analysis techniques for developing safety critical software in the digital protection system of the LMR

Energy Technology Data Exchange (ETDEWEB)

Lee, Jang Soo; Cheon, Se Woo; Kim, Chang Hoi; Sim, Yun Sub

2001-02-01

This report has described the software safety analysis techniques and the engineering guidelines for developing safety critical software to identify the state of the art in this field and to give the software safety engineer a trail map between the code and standards layer and the design methodology and documents layer. We have surveyed the management aspects of software safety activities during the software lifecycle in order to improve the safety. After identifying the conventional safety analysis techniques for systems, we have surveyed in details the software safety analysis techniques, software FMEA(Failure Mode and Effects Analysis), software HAZOP(Hazard and Operability Analysis), and software FTA(Fault Tree Analysis). We have also surveyed the state of the art in the software reliability assessment techniques. The most important results from the reliability techniques are not the specific probability numbers generated, but the insights into the risk importance of software features. To defend against potential common-mode failures, high quality, defense-in-depth, and diversity are considered to be key elements in digital I and C system design. To minimize the possibility of CMFs and thus increase the plant reliability, we have provided D-in-D and D analysis guidelines.

Software safety analysis techniques for developing safety critical software in the digital protection system of the LMR

International Nuclear Information System (INIS)

Lee, Jang Soo; Cheon, Se Woo; Kim, Chang Hoi; Sim, Yun Sub

2001-02-01

This report has described the software safety analysis techniques and the engineering guidelines for developing safety critical software to identify the state of the art in this field and to give the software safety engineer a trail map between the code and standards layer and the design methodology and documents layer. We have surveyed the management aspects of software safety activities during the software lifecycle in order to improve the safety. After identifying the conventional safety analysis techniques for systems, we have surveyed in details the software safety analysis techniques, software FMEA(Failure Mode and Effects Analysis), software HAZOP(Hazard and Operability Analysis), and software FTA(Fault Tree Analysis). We have also surveyed the state of the art in the software reliability assessment techniques. The most important results from the reliability techniques are not the specific probability numbers generated, but the insights into the risk importance of software features. To defend against potential common-mode failures, high quality, defense-in-depth, and diversity are considered to be key elements in digital I and C system design. To minimize the possibility of CMFs and thus increase the plant reliability, we have provided D-in-D and D analysis guidelines

Westinghouse Advances in Passive Plant Safety

International Nuclear Information System (INIS)

Bruschi, H. J.; Manager, General; Gerstenhaber, E.

1993-01-01

On June 26, 1992, Westinghouse submitted the Ap600 Standard Safety Analysis Report and comprehensive PIRA results to the U. S. NRC for review as part of the Ap600 design certification program. This major milestone was met on time on a schedule set more than 3 years before submittal and is the result of the cooperative efforts of the U. S. Department of Energy (DOE), the Electric Power Requirements Program, and the Westinghouse Ap600 design team. These efforts were initiated in 1985 to develop a 600 MW advanced light water reactor plant design based on specific technical requirements established to provide the safety, simplicity, reliability, and economics necessary for the next generation of nuclear power plants. The Ap600 design achieves the ALRR safety requirements through ample design margins, simplified safety systems based on natural driving forces, and on a human-engineered man-machine interface system. Extensive Probabilistic Risk evolution, have recently shown that even if none of the active defense-in-depth safety systems are available, the passive systems alone meet safety goals. Furthermore, many tests in an extensive test program have begun or have been completed. Early tests show that passive safety perform well and meet design expectations

An observational study of defensible space in the neighbourhood park

Science.gov (United States)

Marzukhi, M. A.; Afiq, M. A.; Zaki, S. Ahmad; Ling, O. H. L.

2018-02-01

The planning of neighborhood park is important to provide space for interaction, leisure, and recreation among residents in any neighbourhood area. However, on an almost daily basis, newspapers report inappropriate incidents such as snatch theft, robbery and street attack that occurred in the neighborhood park. These cases reflect the significance of physical planning and design of neighborhood park that directly affect the safety and comfort of the users. Thus, this study attempts to engage with the defensible space concept in ensuring the security elements be applied in the planning of the recreational area. This study adopts a qualitative method form of research that is retrofitted to an observational study. The observational study is significant for revealing the condition of a neighbourhood park in the ‘real-world,’ in which direct observation is conducted on Taman Tasik Puchong Perdana. The observer focused on four elements or variables of defensible space concept including the provision of facilities in the neighborhood park, territoriality, surveillance, image and milieu. The findings revealed that the planning of Taman Tasik Puchong Perdana does not deliberate the defensible space elements, which may contribute to the crime activities in the park. In these circumstances, the planning of neighbourhood park needs to include proposals for the implementation of defensible space in response to the challenges underpinned by crime problems. Besides, the awareness among the residents needs to be emphasized with the support from local authorities and other organizations to manage and sustain the safety environment in the neighborhood park.

The design and safety features of the IRIS reactor

International Nuclear Information System (INIS)

Carelli, Mario D.; Conway, L.E.; Oriani, L.; Petrovic, B.; Lombardi, C.V.; Ricotti, M.E.; Barroso, A.C.O.; Collado, J.M.; Cinotti, L.; Todreas, N.E.; Grgic, D.; Moraes, M.M.; Boroughs, R.D.; Ninokata, H.; Ingersoll, D.T.; Oriolo, F.

2004-01-01

Salient features of the International Reactor Innovative and Secure (IRIS) are presented here. IRIS, an integral, modular, medium size (335 MWe) PWR, has been under development since the turn of the century by an international consortium led by Westinghouse and including over 20 organizations from nine countries. Described here are the features of the integral design which includes steam generators, pumps and pressurizer inside the vessel, together with the core, control rods, and neutron reflector/shield. A brief summary is provided of the IRIS approach to extended maintenance over a 48-month schedule. The unique IRIS safety-by-design approach is discussed, which, by eliminating accidents, at the design stage, or decreasing their consequences/probabilities when outright elimination is not possible, provides a very powerful first level of defense in depth. The safety-by-design allows a significant reduction and simplification of the passive safety systems, which are presented here, together with an assessment of the IRIS response to transients and postulated accidents

GNF Defense in Depth Update

Energy Technology Data Exchange (ETDEWEB)

Lingenfelter, Andrew A.; Schneider, Robert J.; Cantonwine, Paul E.; Moore, Brian; Rea, John; Crawford, Douglas C. [Global Nuclear Fuel, P.O. Box 780 M/C H25, Wilmington, NC 28402 (United States)

2009-06-15

Global Nuclear Fuel (GNF) has designed, fabricated, and placed into operation more than 9 million fuel rods in approximately 135 thousand assemblies. Customer satisfaction has always compelled GNF to reduce fuel rod failures (defined here as fuel rods that breach or leak in service), However, increasing success with and subsequent expectations for economic performance of nuclear reactor plants have raised broader Industry emphasis on fuel reliability. In 2005, GNF established its Defense-in-Depth (DID) Program for the purpose of focusing attention on the many aspects of fuel design, fabrication, performance, and utilization that affect fuel reliability as well as on the key methods that govern the utilization of GNF fuel. The Program is structured to address each of the identified in-service, fuel failure mechanisms. This paper provides a summary of GNF fuel performance, following previous updates. This paper will discuss recent GNF fuel reliability and channel performance, GNF2 introduction status, and methods. GNF's more recent fuel experience includes approximately 3.8 million GE11/13 (9x9) and GE12/14 (10x10) fuel rods, well over half of which are the GE12/14 design. (Those figures also include roughly 25,000 recently-introduced GNF2 fuel rods.) Reliability, expressed as annual, observed fuel failure rates (i.e., number of rods failed each year divided by the number of opportunities, or fuel rods in service), has improved for each year since 2005. The GNF fuel failure rate for years leading up to 2007 and 2008 has been on the order of 5 to 7 ppm (excluding the corrosion events of 2001-2003), and as of this writing (January 2009) the current in-service failure has decreased to around 1.5 ppm. Failures in GE14 fuel rod failures have been primarily due to debris-fretting (> 60%), with other failures being duty-related or yet undetermined. The only failure observed in GNF2 to date was a single, early-life debris failure in a bundle not equipped with GNF

Safety culture : a significant influence on safety in transportation

Science.gov (United States)

2017-08-01

An organizations safety culture can influence safety outcomes. Research and experience show that when safety culture is strong, accidents are less frequent and less severe. As a result, building and maintaining strong safety cultures should be a t...

Safety philosophy and licensing practice in different member states of IAEA: Canada

International Nuclear Information System (INIS)

Boyd, F.C.

1981-01-01

The lecture will provide an outline of the Canadian nuclear organization and basic characteristics of the CANDU reactor as a background for a brief description of the nuclear power plant licensing process and the safety philosophy followed. The regulatory agency (Atomic Energy Control Board) follows a three step licensing procedure, Site Acceptance, Construction Approval, Operating Licence. Defense in depth is followed as a general safety concept, but is applied in a special way. Completely separate and independant safety systems are required and basic criteria established through reference dose limits for any assumed failure (or initiating event) in any process (operating) system and for any such failure combined with complete failure at any safety system. The application of the Canadian approach in other countries will be mentioned. (orig./RW)

Lessons Learned from Process Safety Management: A Practical Guide to Defence in Depth

Energy Technology Data Exchange (ETDEWEB)

Langerman, N., E-mail: neal@chemical-safety.com [Advanced Chemical Safety, Inc., San Diego (United States)

2014-10-15

Full text: Beginning with the experiences of Alfred Nobel, the chemical enterprise has learned from failures and implemented layers of protection to prevent unwanted incidents. Nobel developed dynamite as a more stable alternative to nitroglycerin, a process we would today call “inherently safer technology”. In recent years, the USA has issued regulations requiring formal “risk management plans” to identify and mitigate production risks. The USA set up the “Chemical Safety and Hazard Investigation Board” as an independent investigator of serious chemical enterprise incidents with a mission to issue recommendations aimed at preventing repeated incidents based on lessons learned. Following a particularly violent explosion in Texas in 1989, the US Occupational Safety and Health Administration issued the “Process Safety Management” (PSM) rule. PSM is a singular guide to defence in depth for preventing large-scale production incidents. The formalism is equally applicable to the chemical enterprise and the nuclear installation enterprise. This presentation will discuss the key elements of PSM and offer suggestions on using PSM as a guide to developing multiple layers of protection. The methods of PSM are applicable to Nuclear Generating Stations, research reactors, fuel reprocessing plants and fissile material storage and handling. Examples from both the chemical and nuclear enterprises will be used to illustrate key points. (author)

Objective Provision Trees of Reactivity Control Safety Function for Sodium-Cooled Fast Reactor

Energy Technology Data Exchange (ETDEWEB)

Kang, Bongsuk; Yang, Huichang [TUEV Rheinland Korea Ltd., Seoul (Korea, Republic of); Suh, Namduk [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2014-05-15

The purpose of this OPT is first to assure the DiD design during the licensing of Sf, but it will also contribute in evaluating the completeness of regulatory requirements under development by Korea Institute of Nuclear Safety (KINS). Based on the definition of Defense-in-Depth (DiD) levels and safety functions for KALIMER Sodium-Cooled Fast Reactor (SFR), suggested in the reference and, Objective Provision Trees (OPTs) of reactivity control function for level 1, 2, 3 and 4 DiD were developed and suggested in this paper. The challenges and mechanisms and provisions were briefly explained in this paper. Comparing the mechanisms and provisions with the requirements will contribute in identifying the missing requirements. Since the design of Prototype Gen-IV Sf (PGSFR) is not mature yet, the OPT is developed for KALIMER design. Developed level 1 to 4 OPTs in this study can be used for the identification of potential design vulnerabilities. When detailed identification of provisions in terms of design features were achieved through the next step of this study, it can contribute to the establishment of defense-in-depth evaluation frame for the regulatory reviews for the licensing process. In the next stage of this study, other safety function will be researched and findings can be suggested as recommendations for the safety improvement.

Objective Provision Trees of Reactivity Control Safety Function for Sodium-Cooled Fast Reactor

International Nuclear Information System (INIS)

Kang, Bongsuk; Yang, Huichang; Suh, Namduk

2014-01-01

The purpose of this OPT is first to assure the DiD design during the licensing of Sf, but it will also contribute in evaluating the completeness of regulatory requirements under development by Korea Institute of Nuclear Safety (KINS). Based on the definition of Defense-in-Depth (DiD) levels and safety functions for KALIMER Sodium-Cooled Fast Reactor (SFR), suggested in the reference and, Objective Provision Trees (OPTs) of reactivity control function for level 1, 2, 3 and 4 DiD were developed and suggested in this paper. The challenges and mechanisms and provisions were briefly explained in this paper. Comparing the mechanisms and provisions with the requirements will contribute in identifying the missing requirements. Since the design of Prototype Gen-IV Sf (PGSFR) is not mature yet, the OPT is developed for KALIMER design. Developed level 1 to 4 OPTs in this study can be used for the identification of potential design vulnerabilities. When detailed identification of provisions in terms of design features were achieved through the next step of this study, it can contribute to the establishment of defense-in-depth evaluation frame for the regulatory reviews for the licensing process. In the next stage of this study, other safety function will be researched and findings can be suggested as recommendations for the safety improvement

Progress in the U.S. department of energy sponsored in-depth safety assessments of VVER and RBMK reactors

International Nuclear Information System (INIS)

Binder, J.L.; Petri, M.C.; Pasedag, W.F.

2001-01-01

Since the disastrous accident at Chernobyl Nuclear Power Plant Unit 4 in 1986, there has been international recognition of the safety concerns posed by the operation of 67 Soviet-designed commercial nuclear reactors. These reactors are operated in eight countries from the former Soviet Union and its former satellite states in Central and Eastern Europe. The majority of these plants are in the Russian Federation (30 units) and Ukraine (14 units). New plants are in various stages of construction. U.S. support to improve the safety of Soviet-designed reactors over the past decade has been intended to enhance operational safety, provide for risk-reduction measures, and enhance regulatory capability. The U.S. approach to improving the safety of Soviet-designed reactors has matured into a large multi-year program known as the Soviet-Designed Reactor Safety Program that is managed by the U.S. Department of Energy (US DOE). The mission of the program is to implement a self-sustaining nuclear safety improvement program that would lead to internationally accepted safety practices at the plants. Those practices would create a safety culture that would be reflected in the operation, regulation, and professional attitudes of the designers, operators, and regulators of the nuclear facilities. A key component of this larger program has been the Plant Safety Evaluation Program, which supports in-depth safety assessments of VVER and RBMK plants. (author)

Control Systems Cyber Security:Defense in Depth Strategies

Energy Technology Data Exchange (ETDEWEB)

David Kuipers; Mark Fabro

2006-05-01

Information infrastructures across many public and private domains share several common attributes regarding IT deployments and data communications. This is particularly true in the control systems domain. A majority of the systems use robust architectures to enhance business and reduce costs by increasing the integration of external, business, and control system networks. However, multi-network integration strategies often lead to vulnerabilities that greatly reduce the security of an organization, and can expose mission-critical control systems to cyber threats. This document provides guidance and direction for developing ‘defense-in-depth’ strategies for organizations that use control system networks while maintaining a multi-tier information architecture that requires: Maintenance of various field devices, telemetry collection, and/or industrial-level process systems Access to facilities via remote data link or modem Public facing services for customer or corporate operations A robust business environment that requires connections among the control system domain, the external Internet, and other peer organizations.

Quarterly report on Defense Nuclear Facilities Safety Board Recommendation 90-7

International Nuclear Information System (INIS)

Cash, R.J.; Dukelow, G.T.

1991-10-01

This is the second quarterly report on the progress of activities addressing safety issues associated with Hanford Site high-level radioactive waste tanks that contain ferrocyanide compounds. An implementation plan (Cash 1991) responding to the Defense Nuclear Facilities Safety Board Recommendation 90-7 (FR 1990) was issued in March 1991 describing the activities planned and underway to address each of the six parts of the recommendation. All of the activities listed in the implementation plan are underway, including the multifunctional instrument tree and infrared tasks which resumed in late July. Although technical difficulties and resource limitations delayed some work, noteworthy progress has been made in completing a number of ferrocyanide program milestones. Thermal modeling shows that the heat loading of tank 241-BY-104 is much lower than previously listed and that significant hot spots within the waste are highly unlikely, if not possible. Computerized continuous temperature monitoring was installed on schedule on five of the highest interest tanks and five additional tanks will be on-line in December. Tank intrusive sampling is proceeding and the first vapor samples were obtained in mid-October. Spectral scans were completed for twelve tanks and substantial progress was made on design of an infrared scanning system. Chemical reaction studies are underway with synthetic ferrocyanide compounds believed to be more representative of the ferrocyanide materials actually deposited in the tanks. Tests indicate that water plays a major role in impeding a possible runaway reaction. An emergency planning exercise was conducted in May, emergency procedures were updated this quarter, and validation of the procedures and a second emergency exercise is scheduled for October

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

Improved safety of the system 80+TM standard plants design through increased diversity and redundancy of safety systems

International Nuclear Information System (INIS)

Matzie, Regis A.; Carpentino, Frederick L.; Robertson, James E.

1996-01-01

Safely systems in the System 80+ TM Standard Plant are designed with more redundancy, diversity and simplicity than earlier nuclear power plant designs. These gains were accomplished by an evolutionary process that preserved the desirable and proven features in currently operating nuclear plants, while improving reliability and defense-in-depth. The System 80+ safety systems are the primary contributors to a core damage frequency that is more than 100 times lower than 1980's vintage U. S. designs, including the predecessor System 80 R standard nuclear steam supply system (NSSS) design. The System 80+ design includes significant improvements to the safety injection system, emergency feedwater system, shutdown cooling system, containment spray system, reactor coolant gas vent system, and to their vital support systems. These improvements enhance performance for traditional design basis events and significantly reduce the probability of a severe accident. The System 80+ design also incorporates safety systems to mitigate a severe accident. The added systems include the rapid depressurization system, the in-containment refueling water storage tank, the cavity flooding system. These systems fully address the U. S. Nuclear Regulatory Commission's (US NRC) severe accident policy. The System 80+ safety systems are integrated with the System 80+ Nuclear Island (NI) design. The NI general arrangement provides quadrant separation of the safety systems for protection from fire and flooding, and large equipment pull spaces and lay down areas for maintenance. This paper will describe the System 80+ safety systems advanced design features, the improved accident prevention and mitigation capabilities, and startup, operating and maintenance benefits

Quarterly report on Defense Nuclear Facilities Safety Board Recommendation 90-7 for the period ending December 31, 1991

International Nuclear Information System (INIS)

Cash, R.J.; Dukelow, G.T.; Atwood, J.M.

1992-01-01

This quarterly report provides a status of the activities underway at the Hanford Site on the ferrocyanide safety issues as requested by the Defense Nuclear Facilities Safety Board (DNFSB) in their Recommendation 90-7 (FR 1990). In March 1991, an DNFSB Implementation Plan (Cash 1991a) was prepared and sent to the DNFSB responding to the six parts of Recommendation 90-7. All of the activities in the DNFSB Implementation Plan are underway and the status of each is described

Development of safety function assessment trees for pressurized heavy water reactor LP/SD operations

International Nuclear Information System (INIS)

Yang, Hui Chang; Chung, Chang Hyun; Kim, Ki Yong; Jee, Moon Hak; Sung, Chang Kyoung

2003-01-01

The objective of Configuration Risk Management Program(CRMP) is to maintain the safety level by assuring the defense-in-depth of nuclear power plant while the configurations are changed during plant operations, especially for the LP/SD. Such a safety purpose can be achieved by establishing the risk monitoring programs with both quantitative and qualitative features. Generally, the quantitative risk evaluation models, i.e., PRA models are used for the risk evaluation during full power operation, and the qualitative risk evaluation models such as safety function assessment trees are used. Through this study, safety function assessment trees were developed

Safety considerations of PWR's

International Nuclear Information System (INIS)

Arnold, W.H. Jr.

1977-01-01

The safety of the central station pressurized water reactor is well established and substantiated by its excellent operating record. Operating data from 55 reactors of this type have established a record of safe operating history unparalleled by any modern large scale industry. The 186 plants under construction require a continuing commitment to maintain this outstanding record. The safety of the PWR has been further verified by the recently completed Reactor Safety Study (''Rasmussen'' Report). Not only has this study confirmed the exceptionally low risk associated with PWR operation, it has also introduced a valuable new tool in the decision making process. PWR designs, utilizing the philosophy of defense in depth, provide the bases for evaluating margins of safety. The design of the reactor coolant system, the containment system, emergency core cooling system and other related systems and components provide substantial margins of safety under both normal and postulated accident conditions even considering simultaneous effects of earthquakes and other environmental phenomena. Margins of safety in the assessment of various postulated accident conditions, with emphasis on the postulated loss of reactor coolant accident (LOCA), have been evaluated in depth as exemplified by the comprehensive ECCS rulemaking hearings followed by imposition of very conservative Nuclear Regulatory Commission requirements. When evaluated on an engineering best estimate approach, the significant margins to safety for a LOCA become more apparent. Extensive test programs have also substantiated margins to safety limits. These programs have included both separate effects and systems tests. Component testing has also been performed to substantiate performance levels under adverse combinations of environmental stress. The importance of utilizing past experience and of optimizing the deployment of incremental resources is self evident. Recent safety concerns have included specific areas such

Safety and regulatory researches on the SMART reactor

International Nuclear Information System (INIS)

Seul, Kwang Won; Kim, Wee Kyong; Chang, Moo Hee

2000-01-01

The 330 MW thermal power of integral pressurized water reactor, named SMART (System integrated Modular Advanced ReacTor), is under development at the Korea Atomic Energy Research Institute (KAERI) for seawater desalination application and electricity generation. The plant is expected to install near the population zone. Thus, the public around the plant should be in depth protected from the possible release of radioactive materials, and also the fresh water should be prevented from radioactivity contamination. Currently, in parallel with the design development, the regulatory research is being conducted to identify and resolve the safety concerns of the nuclear desalination plant. Until now, some general items to be considered in the safety aspects have been identified for the conceptual design of SMART. They include the use of proven technology, application of strengthening defense-in-depth, event categorization and selection, effects of desalination plant, and maintainability of major components. These cooperative researches with regulatory body in the design stage are expected to provide an opportunity to early resolve the safety concerns and eventually the licensing stability of the SMART design. (author)

AREVA advanced safety IC solutions and licensing experience for new nuclear builds and modernization projects - 15545

International Nuclear Information System (INIS)

Fourestie, B.; Pickelmann, J.; Richter, S.; Hilsenkopf, P.; Paris, P.

2015-01-01

Regulatory requirements for the Instrumentation and Control (IC) for Nuclear Power Plants have become significantly more stringent during the last 10 years in the areas of software development and qualification, traceability, diversity, or seismic requirements for instance, and with the introduction of new standards (such as the IEC 62566, or the IEC 62003). Based on a large and comprehensive experience gained from projects in several regulatory environments and different plant types (including non-OEM plants), AREVA has developed and adapted its processes and products to provide state-of-the-art IC solutions in full compliance with the regulatory demands and requirements in terms of robustness (independence, defense-in-depth, diversity and cyber-security). In this paper we present the safety IC platforms developed by AREVA. These platforms include TELEPERM XS as the computerized safety IC platform for class 1 system implementation, the Qualified Display System (QDS) for safety classified screen-based interface, and UNICORN as fully diverse analog safety IC platform for backup systems

Nuclear criticality safety analysis summary report: The S-area defense waste processing facility

International Nuclear Information System (INIS)

Ha, B.C.

1994-01-01

The S-Area Defense Waste Processing Facility (DWPF) can process all of the high level radioactive wastes currently stored at the Savannah River Site with negligible risk of nuclear criticality. The characteristics which make the DWPF critically safe are: (1) abundance of neutron absorbers in the waste feeds; (2) and low concentration of fissionable material. This report documents the criticality safety arguments for the S-Area DWPF process as required by DOE orders to characterize and to justify the low potential for criticality. It documents that the nature of the waste feeds and the nature of the DWPF process chemistry preclude criticality

Safety significance evaluation system

International Nuclear Information System (INIS)

Lew, B.S.; Yee, D.; Brewer, W.K.; Quattro, P.J.; Kirby, K.D.

1991-01-01

This paper reports that the Pacific Gas and Electric Company (PG and E), in cooperation with ABZ, Incorporated and Science Applications International Corporation (SAIC), investigated the use of artificial intelligence-based programming techniques to assist utility personnel in regulatory compliance problems. The result of this investigation is that artificial intelligence-based programming techniques can successfully be applied to this problem. To demonstrate this, a general methodology was developed and several prototype systems based on this methodology were developed. The prototypes address U.S. Nuclear Regulatory Commission (NRC) event reportability requirements, technical specification compliance based on plant equipment status, and quality assurance assistance. This collection of prototype modules is named the safety significance evaluation system

Introduction to South Africa's safety classification

Energy Technology Data Exchange (ETDEWEB)

Kang, Kyung Jun; Wu, Sang Ik; Yoon, Juh Yeon [KAERI, Daejeon (Korea, Republic of)

2012-10-15

The safety functions of nuclear reactor facilities such as research reactors have to be maintained for all initiating events, incidents and accidents. From the position of licensee, it is a very important issue and design challenge to meet the licensing requirements for the final goal of proper safety functions from nuclear regulator. This paper intends to introduce and understand South Africa's licensing requirements and processing for safety classification of SSCs. South Africa's licensing requirements are shown in Table 1. Three categories A, B and C are categorized based on the occurrence frequency and the dose limitation of worker and public exposure. The Defense in Depth (DiD) and ALARA principle are forced to apply to a nuclear reactor facility design. Also, South Africa's safety and quality class compare with that of ANSI 51.1.

International review of Kursk unit 1 in-depth safety analysis report

International Nuclear Information System (INIS)

Chouha, M.; Bolshov, L.; Butcher, P.; Janke, R.; Parsons, T.; Weber, J.P.

2004-01-01

The paper presents the objectives, organisation, main findings and conclusions of the international review of the Kursk unit 1 safety analysis report (K1IRSR). The K1IRSR was administered by RISKAUDIT IRSN/GRS international and carried out by international experts from 7 western countries plus the Russian Federation, under the supervision of the safety review group (SRG) of the European bank for reconstruction and development (EBRD). The project was financed by the nuclear safety account (NSA) administered by the EBRD. The Russian experts worked under a contract with IBRAE financed by Rosenergoatom. The main conclusions were that the SAR followed a correct approach, broadly in line with Russian and international guidance documents, but needed improvement in structure and content. It established that the safety level of the unit has been increased significantly by the modernisation programme. The important deviations of the unit from current Russian regulations and the IAEA safety issues for RBMK are either fully resolved or are being addressed to the extent possible by compensatory measures to further reduce the risk. The K1IRSR experts have made a number of recommendations for improvement of the K1SAR. The authors agreed to take the recommendations into account in future revision of the K1SAR. (orig.)

2004 annual report. Defense, safety, energy, information, health. CEA in the center of big European challenges

International Nuclear Information System (INIS)

2005-01-01

This document is the 2004 annual report of the French atomic energy commission (CEA). It presents the R and D activities of the CEA in three main domains: 1 - defense and safety, maintaining perenniality of nuclear dissuasion and nuclear safety: supplying nuclear weapons to armies, maintaining dissuasion capability with the simulation program, sharing R and D means with the scientific community and the industrial world, designing and maintaining naval nuclear propulsion reactors, cleansing Marcoule and Pierrelatte facilities, monitoring treaties and fighting against proliferation and terrorism; 2 - energy, developing more competitive and cleaner energy sources: nuclear waste management, optimization of industrial nuclear activities, future nuclear systems and new energy technologies, basic research on energy, radiobiology and toxicology; 3 - information and health, valorizing industry thanks to technological research and supplying new tools for health and medical research: micro- and nano-technologies, software technologies, basic research for industrial innovation, nuclear technologies for health and bio-technologies. (J.S.)

Common cause failure: enhancing defenses against root cause and coupling factor

Energy Technology Data Exchange (ETDEWEB)

Kaushik, Poorva; Kim, Sok Chul [KINS, Daejeon (Korea, Republic of)

2016-10-15

A Common Cause Failure(CCF) event refers to a specific class of dependent events that result from co-existence of two main factors: Susceptibility of components to fail or become unavailable due to particular root cause of failure, and coupling factor coupling mechanism) that creates the condition for multiple components getting affected. PSA (Probabilistic Safety Assessment) operating experience of Nuclear Power Plants have demonstrated that dependent events such as CCF events are major contributor to risk during operation. From cost-benefit consideration, putting significant design modifications in place to prevent CCF would not be desirable in terms of risk management regulatory effectiveness and efficiency. The aim of this study was to propose feasible defenses against CCF from cost benefit consideration to enhance the safety. This study provides the CDM and CFDM of EDG. Defenses employed against cause and coupling factor can be easily employed in operation and maintenance programme of NPP and are not an additional cost burden. Such enhancement of defense against the CCF can give a modest improvement in CDF. This approach is specifically helpful in plants that are already under operation and significant modifications are not economically feasible.

The Defence in Depth Concept Applied to the New Regulatory Requirements in Japan

Energy Technology Data Exchange (ETDEWEB)

Yamagata, H., E-mail: hiroshi_yamagata@nsr.go.jp [Nuclear Regulation Authority, Minato-ku, Tokyo (Japan)

2014-10-15

Full text: The new regulatory requirements based on lessons learnt from Fukushima Daiichi accident, which places emphasis on Defense-in-Depth concept, was put into effect in Japan on 8th July, 2013. It is required to prepare multi-layered protective measures. Each layer should achieve the objective only in that layer regardless of the measures in the other layers. The challenge is how to enhance independence of measures between layers. In the third layer, the current concept of design regarding safety relies on “single failure”, whose condition is elimination of common cause failure (CCF). To eliminate CCFs we introduced a more accurate approach in assessment of earthquake and tsunami, and introduction of measures against tsunami inundation. Redundancy of safety systems could not eliminate CCF by extreme natural hazards. Safety system should be designed by due consideration of diversity and independence including spatial dispersement. In the fourth layer, multi-layered protective measures are also applied for severe accidents, which consists of “prevention of core damage” under multiple failure, “prevention of containment failure”, and “prevention of large release, that is controlled release by venting”. In the fifth layer, we also require operators to prepare measures for “suppression of radioactive materials dispersion”. Of course, off-site emergency preparedness and response has been enhanced by introduction of PAZ and UPZ. Introduction of “Specialized Safety Facility” against intentional aircraft crash will contribute enhancement of some layers by providing electricity and water under extremely severe conditions. The new regulatory requirements are not our goal, just a first step. It is expected for regulator and operators to improve safety continuously by periodic comprehensive safety assessments including IPE, IPEEE, Margin test, and etc. We have to make an upward spiral of nuclear safety. (author)

Report from the nuclear safety authority about the preparation of nuclear facilities to the year 2000 transition

International Nuclear Information System (INIS)

Lacoste, A.C.

1999-01-01

The French nuclear safety authority with the technical help of the Institute of Nuclear Protection and Safety (IPSN) started in 1998 an evaluation and control work of the measures taken by the different nuclear facility operators in anticipation of the year 2000 transition. This report makes a status of the state of preparation of nuclear facilities prior to the transition: 1 - The nuclear safety and the year 2000 transition (defense-in-depth approach, preventive actions); 2 - The action of the safety authority (demands addressed to the operators of nuclear facilities, technical evaluation and control of the methodology adopted by each operator, preparation of the safety authority to the transition, follow up of the international actions); 3 - Status of the preparation of the different operators: Electricite de France (EdF) (corrective actions, inventory and investigation of computer systems, results, corrections, preventive actions, defensive actions, synthesis), research centres, storage sites and shutdown reactors, waste storage centres of the ANDRA, CEA facilities, decommissioned or partially dismantled reactors, fuel cycle centres.. (J.S.)

Status of conceptual safety design study of Japanese sodium-cooled fast reactor

International Nuclear Information System (INIS)

Kubo, Shigenobu; Kurisaka, Kenichi; Niwa, Hajime; Shimakawa, Yoshio

2005-01-01

In this paper, the current conceptual safety design and related evaluation of Japanese Sodium-cooled Fast Reactor which is studied in the framework of the Feasibility Study (FS) on commercialized Fast Reactor Cycle Systems in Japan are described. The purpose of the safety design is to establish a feasible safety concept of FBR which aims at a sustainable energy source of the next generations. The safety targets and the safety design principle are set aiming at realizing worldwide acceptability of the safety level. The basic safety design concept, which can meet the safety targets, was formulated taking along with the defense-in-depth philosophy as the basic safety design principle. In order to cope with wide range of energy and resource demands, there are some various designs both of oxide and metal fuel for JSFR. Some analytical results of typical design basis events, design extension conditions and core damage frequency estimation show the feasibility of the safety design concept for them. (author)

77 FR 51943 - Procedures for Safety Investigations

Science.gov (United States)

2012-08-28

... rule, Procedures for Safety Investigations, which published July 27, 2012 in the Federal Register, 77... DEFENSE NUCLEAR FACILITIES SAFETY BOARD 10 CFR Part 1708 Procedures for Safety Investigations AGENCY: Defense Nuclear Facilities Safety Board. ACTION: Proposed rule; extension of comment period...

Experience in safety review of design solutions of the state-of-the-art WWER-type NPPs

International Nuclear Information System (INIS)

Khamaza, A.A.

2015-01-01

The experience of the Federal Budget Institution of the Scientific and Technical Center for Nuclear and Radiation Safety in the field of expertise of the safety rationales for nuclear power plants with WWER-type reactors of new projects is disclosed. In determining the priority, in addition to the necessary time and financial resources, it also took into account the extent to which these activities significantly affect the completeness of the implementation of levels of defense in depth related to the management of beyond-design-basis accidents, including severe ones. And also, what impact does this or that measure have on reducing the likelihood of the onset of severe radiation effects. When examining the safety justification for new design solutions (including for nuclear power plants with a reactor type WWER), it is advisable to adhere to the following approach: during the examination it is necessary to study the experience in the country and the world related to the proposed new design solutions; It is preferable to take advantage of the differential approach to assessing various aspects related to nuclear and radiation safety. The result of the examination of the justification for new design solutions may be recommendations on the development of existing regulatory documents or development of the Regulatory Authority [ru

Strategic variation in mobbing as a front line of defense against brood parasitism.

Science.gov (United States)

Welbergen, Justin A; Davies, Nicholas B

2009-02-10

Coevolutionary arms races, where adaptations in one party select for counter-adaptations in another and vice versa, are fundamental to interactions between organisms and their predators, pathogens, and parasites [1]. Avian brood parasites and their hosts have emerged as model systems for studying such reciprocal coevolutionary processes [2, 3]. For example, hosts have evolved changes in egg appearance and rejection of foreign eggs in response to brood parasitism from cuckoos, and cuckoos have evolved host-egg mimicry as a counter-response [4-6]. However, the host's front line of defense is protecting the nest from being parasitized in the first place [7-10], yet little is known about the effectiveness of nest defense as an antiparasite adaptation, and its coevolutionary significance remains poorly understood [10]. Here we show first that mobbing of common cuckoos Cuculus canorus by reed warblers Acrocephalus scirpaceus is an effective defense against parasitism. Second, mobbing of cuckoos is a phenotypically plastic trait that is modified strategically according to local parasitism risk. This supports the view that hosts use a "defense in-depth strategy," with successive flexible lines of defense that coevolve with corresponding offensive lines of the parasite. This highlights the need for more holistic research into the coevolutionary consequences when multiple adaptations and counter-adaptations evolve in concert [11].

Cyber security level assignment for research reactor digital instrumentation and control system architecture using concept of defense in depth

International Nuclear Information System (INIS)

Shin, Jin Soo; Heo, Gyun Young; Son, Han Seong; Kim, Young Ki; Park, Jaek Wan

2012-01-01

Due to recent aging of the analog instrumentation of many nuclear power plants (NPPs) and research reactors, the system reliability decreases while maintenance and testing costs increase. In addition, it is difficult to find the substitutable analog equipment s due to obsolescence. Therefore, the instrumentation and control (I and C) systems have changed from analog system to digital system due to these facts. With the introduction of digital systems, research reactors are forced to care for the problem of cyber attacks because I and C systems have been digitalized using networks or communication systems. Especially, it is more issued at research reactors due to the accessibility of human resources. In the real world, an IBM researcher has been successful in controlling the software by penetrating a NPPs network in U.S. on July 2008 and acquiring the control right of nuclear facilities after one week. Moreover, the malignant code called 'stuxnet' impaired the nearly 1,000 centrifugal separators in Iran according to an IAEA report. The problem of cyber attacks highlights the important of cyber security, which should be emphasized. Defense.in.depth (DID) is a significant concept for the cyber security to work properly. DID institutes and maintains a hardy program for critical digital asset (CDA) by implementing multiple security boundaries. In this work, we assign cyber security levels to a typical digital I and C system using DID concept. This work is very useful in applying the concept of DID to nuclear industry with respect to cyber security

Cyber security level assignment for research reactor digital instrumentation and control system architecture using concept of defense in depth

Energy Technology Data Exchange (ETDEWEB)

Shin, Jin Soo; Heo, Gyun Young [Kyung Hee University, Seoul (Korea, Republic of); Son, Han Seong [Joongbu Univ., Chungnam (Korea, Republic of); Kim, Young Ki; Park, Jaek Wan [KAERI, Daejeon (Korea, Republic of)

2012-10-15

Due to recent aging of the analog instrumentation of many nuclear power plants (NPPs) and research reactors, the system reliability decreases while maintenance and testing costs increase. In addition, it is difficult to find the substitutable analog equipment s due to obsolescence. Therefore, the instrumentation and control (I and C) systems have changed from analog system to digital system due to these facts. With the introduction of digital systems, research reactors are forced to care for the problem of cyber attacks because I and C systems have been digitalized using networks or communication systems. Especially, it is more issued at research reactors due to the accessibility of human resources. In the real world, an IBM researcher has been successful in controlling the software by penetrating a NPPs network in U.S. on July 2008 and acquiring the control right of nuclear facilities after one week. Moreover, the malignant code called 'stuxnet' impaired the nearly 1,000 centrifugal separators in Iran according to an IAEA report. The problem of cyber attacks highlights the important of cyber security, which should be emphasized. Defense.in.depth (DID) is a significant concept for the cyber security to work properly. DID institutes and maintains a hardy program for critical digital asset (CDA) by implementing multiple security boundaries. In this work, we assign cyber security levels to a typical digital I and C system using DID concept. This work is very useful in applying the concept of DID to nuclear industry with respect to cyber security.

Safety in depth for nuclear waste disposal

Energy Technology Data Exchange (ETDEWEB)

Ringwood, T [Australian National Univ., Canberra. Research School of Earth Sciences

1980-11-27

A nuclear waste disposal strategy is described in which the radionuclides are immobilised in widely-dispersed drill holes in an extremely stable and leach resistant titanate ceramic form (SYNROC) at depths of 1500 to 4000 metres. The advantages of this method over that of burying such wastes in large centralised mined repositories at 500 to 700 metres in suitable geological strata are examined.

International Conference on Topical Issues in Nuclear Installation Safety: Defence in Depth — Advances and Challenges for Nuclear Installation Safety. Proceedings of an International Conference held in Vienna, Austria, 21-24 October 2013

Energy Technology Data Exchange (ETDEWEB)

NONE

2014-10-15

The fifth International Conference on Topical Issues in Nuclear Installation Safety was dedicated to the defence in depth (DID) concept which is fundamental to the safety of nuclear installations. The main focus of the conference was to foster the exchange of information on the implementation of DID and the associated challenges. This CD-ROM contains the papers presented at the conference as well as the summary and conclusions, including recommendations for further actions to strengthen DID and its implementation.

French PWR Safety Philosophy

International Nuclear Information System (INIS)

Conte, M. M.

1986-01-01

The first 900 MWe units, built under the American Westinghouse licence and with reference to the U. S. regulation, were followed by 28 standardized units, C P1 and C P2 series. Increasing knowledge and lessons learned from starting and operating experience of French nuclear power plants, completed by the experience learned from the operation of foreign reactors, has contributed to the improvement of French PWR design and safety philosophy. As early as 1976, this experience was taken into account by French Safety organisms to discuss, with Electricite de France, the safety options for the planned 1300 MWe units, P4 and P4 series. In 1983, the new reactor scheduled, Ni4 series 1400 MWe, is a totally French design which satisfies the French regulations and other French standards and codes. Based on a deterministic approach, the French safety analysis was progressively completed by a probabilistic approach each of them having possibilities and limits. Increasing knowledge and lessons learned from operating experience have contributed to the French safety philosophy improvement. The methodology now applied to safety evaluation develops a new facet of the in depth defense concept by taking highly unlikely events into consideration, by developing the search of safety consistency of the design, and by completing the deterministic approach by the probabilistic one

Significance of Waterway Navigation Positioning Systems On Ship's Manoeuvring Safety

Science.gov (United States)

Galor, W.

The main goal of navigation is to lead the ship to the point of destination safety and efficiently. Various factors may affect ship realisating this process. The ship movement on waterway are mainly limited by water area dimensions (surface and depth). These limitations cause the requirement to realise the proper of ship movement trajectory. In case when this re requirement cant't fulfil then marine accident may happend. This fact is unwanted event caused losses of human health and life, damage or loss of cargo and ship, pollution of natural environment, damage of port structures or blocking the port of its ports and lost of salvage operation. These losses in same cases can be catas- trophical especially while e.i. crude oil spilling could be place. To realise of safety navigation process is needed to embrace the ship's movement trajectory by waterways area. The ship's trajectory is described by manoeuvring lane as a surface of water area which is require to realise of safety ship movement. Many conditions affect to ship manoeuvring line. The main are following: positioning accuracy, ship's manoeuvring features and phenomena's of shore and ship's bulk common affecting. The accuracy of positioning system is most important. This system depends on coast navigation mark- ing which can range many kinds of technical realisation. Mainly used systems based on lights (line), radionavigation (local system or GPS, DGPS), or radars. If accuracy of positiong is higer, then safety of navigation is growing. This article presents these problems exemplifying with approaching channel to ports situated on West Pomera- nian water region.

Examination of risk significant configuration during low power and shutdown with ORION and PSA

Energy Technology Data Exchange (ETDEWEB)

Park, Chul Kyu; Oh, Seung Jong [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2015-10-15

This paper suggests an approach to calculate the increased CDF corresponding to Orange and Red states in ORION program and analyzed the result of calculation. This approach is expected to be useful for checking the adequacy of the LPSD PSA. And also, the result of this calculation can provide the information about which SSCs for certain SF are more sensitive to risk in particular POS. Defense-in-depth is a safety philosophy in which multiple lines of defense and conservative design and evaluation methods are applied to ensure the safety of the public. Based on this philosophy EPRI developed Outage Risk Assessment and Management (ORAM) program as a qualitative assessment to better manage the risk during low power and shutdown event after the Vogtle loss of vital AC power and RHR event in 1990. Each risk level of RED, ORANGE color status caused by the degradation of each key safety function might be different depend on the importance of each key safety function. However we can't know how much different. If we know the quantitative information about the risk level represented by color, we can take and prepare concrete actions to reduce the risk level of the plant with rescheduling maintenance, strengthen surveillance for important safety function, and developing outage management strategy. The probabilistic safety analysis for low power and shutdown period can provide risk information with quantitative value related on the degradation of redundancy and diversity level for the safety functions during outage. In this study, we calculated the increased Core Damage frequency (CDF) of each RED and ORANGE states in ORION program caused by the degradation of each key safety function by modifying LPSD PSA model. The result of calculation and analysis could be effective to check adequacy and find improvement for these two methods.

A risk-informed perspective on deterministic safety analysis of nuclear power plants

International Nuclear Information System (INIS)

Wan, P.T.

2009-01-01

In this work, the deterministic safety analysis (DSA) approach to nuclear safety is examined from a risk-informed perspective. One objective of safety analysis of a nuclear power plant is to demonstrate via analysis that the risks to the public from events or accidents that are within the design basis of the power plant are within acceptable levels with a high degree of assurance. This nuclear safety analysis objective can be translated into two requirements on the risk estimates of design basis events or accidents: the nominal risk estimate to the public must be shown to be within acceptable levels, and the uncertainty in the risk estimates must be shown to be small on an absolute or relative basis. The DSA approach combined with the defense-in-depth (DID) principle is a simplified safety analysis approach that attempts to achieve the above safety analysis objective in the face of potentially large uncertainties in the risk estimates of a nuclear power plant by treating the various uncertainty contributors using a stylized conservative binary (yes-no) approach, and applying multiple overlapping physical barriers and defense levels to protect against the release of radioactivity from the reactor. It is shown that by focusing on the consequence aspect of risk, the previous two nuclear safety analysis requirements on risk can be satisfied with the DSA-DID approach to nuclear safety. It is also shown the use of multiple overlapping physical barriers and defense levels in the traditional DSA-DID approach to nuclear safety is risk-informed in the sense that it provides a consistently high level of confidence in the validity of the safety analysis results for various design basis events or accidents with a wide range of frequency of occurrence. It is hoped that by providing a linkage between the consequence analysis approach in DSA with a risk-informed perspective, greater understanding of the limitation and capability of the DSA approach is obtained. (author)

Study of flood defense structural measures priorities using Compromise Programming technique

Science.gov (United States)

Lim, D.; Jeong, S.

2017-12-01

Recent climate change of global warming has led to the frequent occurrence of heavy regional rainfalls. As such, inundation vulnerability increases in urban areas with high population density due to the low runoff carrying capacity. This study selects a sample area (Janghang-eup, the Republic of Korea), which is one of the most vulnerable areas to flooding, analyzing the urban flood runoff model (XP-SWMM) and using the MCDM (Multi-Criteria Decision Making) technique to establish flood protection structural measures. To this end, we compare the alternatives and choose the optimal flood defense measure: our model is utilized with three flood prevention structural measures; (i) drainage pipe construction; (ii) water detention; and (iii) flood pumping station. Dividing the target area into three small basins, we propose flood evaluations for an inundation decrease by studying the flooded area, the maximum inundation depth, the damaged residential area, and the construction cost. In addition, Compromise Programming determines the priority of the alternatives. As a consequent, this study suggests flood pumping station for Zone 1 and drainage pipe construction for Zone 2 and Zone 3, respectively, as the optimal flood defense alternative. Keywords : MCDM; Compromise Programming; Urban Flood Prevention; This research was supported by a grant [MPSS-DP-2013-62] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

Urban youth, fear of crime, and resulting defensive actions.

Science.gov (United States)

Williams, J S; Singh, B K; Singh, B B

1994-01-01

One of the most neglected populations studied in victimology has been juveniles. The present study examines the impact of fear of crime among a sample of urban youth on their defensive actions. Studies of urban adult populations have found that a significant number of people fear to venture outside their homes at night. When they do go out, they often take defensive measures to insure their safety. Carrying "mace," whistles, guns, knives, and clubs, for example, is not uncommon. Some have indicated that they have undertaken training in a variety of self-defensive arts and/or keep dogs to protect themselves from the possibility of being victimized. Using data collected from a sample of 1,775 urban youth in 1986 it was found that this population has taken many of the same defensive actions. Only 11% of the sample indicated that they had not taken any defensive actions as a result of fear of crime. Nearly three-fifths took the precaution of having an escort when they went out at night. Learning a technique of self-defense was reported by 19% of the sample; 10% indicated that they carried "mace" or some other type of repellant. Only 4% reported that they carried a whistle because of crime concerns. Significant predictors of personal defensive actions include gender, crime-witnessing status, victimization status and type of victimization (theft vs. witnessing Other defensive actions taken by members of the respondents' households included installing a burglar alarm (22%), keeping a "trained dog" (17%), keeping lights on a night (39%), and installing security locks (38%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Study of defense styles, defenses and coping strategies in alcohol-dependent population].

Science.gov (United States)

Ribadier, A; Varescon, I

2017-05-01

Defense mechanisms have been seen to greatly change over time and across different definitions made by different theoretical currents. Recently with the definition provided by the DSM IV, defense mechanisms have integrated the concept of coping as a defensive factor. These mechanisms are no longer considered just through a psychodynamic approach but also through a cognitive and behavioral one. In recent years, new theories have therefore integrated these two components of the defensive operation. According to Chabrol and Callahan (2013), defense mechanisms precede coping strategies. In individuals with psychopathological disorders, these authors indicate a relative stability of these mechanisms. Also, we asked about the presence of unique characteristics among people with alcohol dependence. Indeed, studies conducted with people with alcohol dependence highlight the presence of a neurotic defense style and some highly immature defenses (projection, acting out, splitting and somatization). In terms of coping strategies, persons with alcohol dependence preferentially use avoidant strategies and strategies focused on emotion. However, although several studies have been conducted to assess coping strategies and defense styles within a population of individuals with an alcohol problem, at the present time none of them has taken into account all these aspects of defense mechanisms. The aim of this study is therefore to study the defenses and defense styles and coping strategies in an alcohol-dependent population. This multicenter study (3 CHU, 1 center of supportive care and prevention in addiction and 1 clinic) received a favorable opinion of an Institutional Review Board (IRB Registration #: 00001072). Eighty alcohol-dependent individuals responded to a questionnaire assessing sociodemographic characteristics and elements related to the course of consumption. Coping strategies were assessed by means of a questionnaire validated in French: the Brief Cope. The Defense

Introduction of the Amendment of IAEA Safety Requirements Reflected Lessons Learned from Fukushima Nuclear Accident

Energy Technology Data Exchange (ETDEWEB)

Ahn, Sang-Kyu; Ahn, Hyung-Joon; Kim, Sun-Hae; Cheong, Jae-Hak [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-10-15

The following five Safety Requirements publications were amended: Governmental, Legal and Regulatory Framework for Safety (GSR Part 1, 2010), Site Evaluation for Nuclear Installations (NS-R-3, 2003), Safety of Nuclear Power Plants: Design (SSR-2/1, 2012), Safety of Nuclear Power Plants: Commissioning and Operation (SSR-2/2, 2011), and Safety Assessment for Facilities and Activities (GSR Part 4, 2009). Figure 1 shows IAEA Safety Standards Categories Major amendments of five Safety Requirements publications were introduced and analyzed in this study. The five IAEA safety requirements publications which are GSR Part 1 and 4, NS-R-3 and SSR-2/1 and 2, were amended to reflect the lesson learned from the Fukushima accident and other operating experiences. Specially, 36 provisions were modified and the new 29 provision with 1 requirement (No. 67: Emergency response facilities on the site) of the SSR-2/1 were established. Since the Fukushima accident happened, a new word, design extension conditions (DECs) which cover substantially the beyond design basis accidents (BDBA), including severe accident conditions, was created and more elaborated by the world nuclear experts. Design extension conditions could include conditions in events without significant fuel degradation and conditions with core melting. Figure 2 shows the range of the DECs. The amendment of the five IAEA safety requirements publications are focused at the prevention of initiating events, which would lead to the DECs, and mitigation of the consequences of DECs by the enhanced defense in depth principle. The following examples of the IAEA requirements to prevent the initiating events are: margins for withstanding external events; margins for avoiding cliff edge effects; safety assessment for multiple facilities or activities at a single site; safety assessment in cases where resources at a facility are shared; consideration of the potential occurrence of events in combination; establishing levels of hazard

Critical Characteristics of Radiation Detection System Components to be Dedicated for use in Safety Class and Safety Significant System

International Nuclear Information System (INIS)

DAVIS, S.J.

2000-01-01

This document identifies critical characteristics of components to be dedicated for use in Safety Significant (SS) Systems, Structures, or Components (SSCs). This document identifies the requirements for the components of the common, radiation area, monitor alarm in the WESF pool cell. These are procured as Commercial Grade Items (CGI), with the qualification testing and formal dedication to be performed at the Waste Encapsulation Storage Facility (WESF) for use in safety significant systems. System modifications are to be performed in accordance with the approved design. Components for this change are commercially available and interchangeable with the existing alarm configuration This document focuses on the operational requirements for alarm, declaration of the safety classification, identification of critical characteristics, and interpretation of requirements for procurement. Critical characteristics are identified herein and must be verified, followed by formal dedication, prior to the components being used in safety related applications

Safety in nuclear power plants

International Nuclear Information System (INIS)

Koeberlein, K.

1987-01-01

In nuclear power plants large amounts of radioactive fission products ensue from the fission of uranium. In order to protect the environment, the radioactive material is confined in multiple 'activity barriers' (crystal matrix of the fuel, fuel cladding, coolant boundary, safety containment, reactor building). These barriers are protected by applying a defense-in-depth concept (high quality requirements, protection systems which recognize and terminate operational incidents, safety systems to cope with accidents). In spite of a favorable safety record of German nuclear power plants it is obvious - and became most evident by the Chernobyl accident - that absolute safety is not achievable. At Chernobyl, however, design disadvantages of that reactor type (like positive reactivity feedback of coolant voiding, missing safety containment) played an important role in accident initiation and progression. Such features of the Russian 'graphite-moderated pressure tube boiling water reactor' are different from those of light water reactors operating in western countries. The essential steps of the waste management of the nuclear fuel cycle ('Entsorgung') are the interim storage, the shipment, and the reprocessing of the spent fuel and the final repository of radioactive waste. Reprocessing means the separation of fossil material (uranium, plutonium) from radioactive waste. Legal requirements for radiological protection of the environment, which are identical for nuclear power plants and reprocessing plant, are complied with by means of comprehensive filter systems. Safety problems of a reprocessing plant are eased considerably by the fact that system pressures, process temperatures and energy densities are low. In order to confine the radioactive waste from the biosphere for a very long period of time, it is to be discarded after appropriate treatment into the deep geological underground of salt domes. (orig./HP) [de

Reinforcement of Defence-in-Depth: Modification Practice After the Fukushima Nuclear Accident

Energy Technology Data Exchange (ETDEWEB)

Wang, Y.; Tang, H.; Mao, Q., E-mail: wangyuhong@cgnpc.com.cn [China Nuclear Power Design Co., Ltd Xia Meilin, Futian District, Shenzhen, Guangdong Province (China)

2014-10-15

The Fukushima Daiichi nuclear accident revealed the importance and demand for further reinforcement of defence in- depth. CGN (China General Nuclear Power Group) has made a complete safety assessment on CPR1000 nuclear power plants under construction in China. Dozens of modifications have been implemented based on the assessment findings and lessons learned from Fukushima nuclear accident, taking into account of PSA (Probabilistic Safety Analysis) and comparison analysis of the latest regulations and standards. These modifications help to enhance nuclear safety significantly for nuclear power plants under construction in China, and provide helpful modification guidance for nuclear power plants in operation of the same type. (author)

Audit Report The Procurement of Safety Class/Safety-Significant Items at the Savannah River Site

International Nuclear Information System (INIS)

2009-01-01

the Savannah River Site. Our review disclosed that the Department had procured and installed safety-class and safety-significant SSCs that did not meet NQA-1 quality standards. Specifically, we identified multiple instances in which critical components did not meet required quality and safety standards. For example: (1) Three structural components were procured and installed by the prime contractor at Savannah River during construction of the MOX Facility that did not meet the technical specifications for items relied on for safety. These substandard items necessitated costly and time consuming remedial action to, among other things, ensure that nonconforming materials and equipment would function within safety margins; (2) In six instances, items used in the construction of TEF failed to satisfy quality standards. In one of these situations, operating procedures had to be modified to ensure that the problem item did not compromise safety; and (3) Finally, at the ISP, one component that did not meet quality standards was procured. The failure of the item could have resulted in a spill of up to 15,000 gallons of high-level radioactive waste. Based on an extensive examination of relevant internal controls and procurement practices, we concluded that these failures were attributable to inadequate attention to quality assurance at Savannah River. Simply put, Departmental controls were not adequate to prevent and/or detect quality assurance problems. For example, Federal and prime contractor officials did not expressly require that subcontractors or lower-tiered vendors comply with quality assurance requirements. Additionally, management did not effectively communicate quality assurance concerns between the several Departmental program elements operating at Savannah River. The procurement and installation of these nonconforming components resulted in cost increases. For example, as of October 2008, the MOX Facility had incurred costs of more than $680,000 due to problems

Reactor safety research against the backdrop of the Energy-Omnibus Law

International Nuclear Information System (INIS)

Kuczera, B.

1995-01-01

On July 19, 1994, the German Federal Parliament adopted the Coal/Nuclear Power Omnibus Law, in which a new quality of safety of future nuclear power plants has been laid down. The defense-in-depth safety concept underlying the nuclear power plants currently in operation is derived from the principle of safety precautions made against reactor accidents, and encompasses preventive measures of accident mangement and mitigating measures of containing possible consequences. Accident management leads to the requirement that even in the most unlikely accidents with core meltdown the consequences remain limited to the plant. A new quality in reactor safety is represented by the System 80+ advanced pressurized water reactor and by the European Pressurized Water Reactor, EPR. Despite different views about the approaches used to address individaul aspects in the achievement of safety goals, there is agreement on the principle that risk provisions, by achieving more transparency, are to result in better public acceptance of the peaceful uses of nuclear power. (orig.) [de

Institutional Strength in Depth

International Nuclear Information System (INIS)

Weightman, M.

2016-01-01

Much work has been undertaken in order to identify, learn and implement the lessons from the TEPCO Fukushima Daiichi nuclear accident. These have mainly targeted on engineering or operational lessons. Less attention has been paid to the institutional lessons, although there have been some measures to improve individual peer reviews, particularly by the World Association of Nuclear Operators, and the authoritative IAEA report published in 2015 brought forward several important lessons for regulators and advocated a system approach. The report noted that one of the contributing factors the accident was the tendency of stakeholders not to challenge. Additionally, it reported deficiencies in the regulatory authority and system. Earlier, the root cause of the accident was identified by a Japanese independent parliamentary report as being cultural and institutional. The sum total of the institutions, the safety system, was ineffective. While it is important to address the many technical and operational lessons these may not necessary address this more fundamental lesson, and may not serve to provide robust defences against human or institutional failings over a wide variety of possible events and combinations. The overall lesson is that we can have rigorous and comprehensive safety standards and other tools in place to deliver high levels of safety, but ultimately what is important is the ability of the nuclear safety system to ensure that the relevant institutions diligently and effectively apply those standards and tools — to be robust and resilient. This has led to the consideration of applying the principles of the strength in depth philosophy to a nuclear safety system as a way of providing a framework for developing, assessing, reviewing and improving the system. At an IAEA conference in October 2013, a model was presented for a robust national nuclear safety system based on strength in depth philosophy. The model highlighted three main layers: industry, the

Using level-I PRA for enhanced safety of the advanced neutron source reactor

International Nuclear Information System (INIS)

Ramsey, C.T.; Linn, M.A.

1995-01-01

The phase-1, level-I probabilistic risk assessment (PRA) of the Advanced Neutron Source (ANS) reactor has been completed as part of the conceptual design phase of this proposed research facility. Since project inception, PRA and reliability concepts have been an integral part of the design evolutions contributing to many of the safety features in the current design. The level-I PRA has been used to evaluate the internal events core damage frequency against project goals and to identify systems important to safety and availability, and it will continue to guide and provide support to accident analysis, both severe and nonsevere. The results also reflect the risk value of defense-in-depth safety features in reducing the likelihood of core damage

Role of Laws and Regulations For Nuclear Energy Installation in Developing Safety Measures Against Accident

International Nuclear Information System (INIS)

Hussein, A.Z.; Zakaria, Kh.M.

2011-01-01

The energy industry has been considered as an economic development driver. The fundamental safety policy for nuclear facilities is to protect health and safety of the public and the site personnel against undue risks associated with radiation and radioactive materials resulting from normal operation and abnormal conditions. This policy is implemented, based on the as low as reasonably achievable (ALARA) principle for normal operation and the defense-in-depth principle (prevention of the occurrence of anomalies, prevention of the escalation of anomalies into accidents, and prevention of excessive release of radioactive materials into the environment), through establishment of safety guides and standards. More over the consideration of suitable site selection and safety design, verification by safety evaluation, quality assurance for manufacturing, construction and operation, periodic testing and inspection, confirmation by regulatory bodies, and reflection of experienced troubles to safety countermeasures. Are of these paramount importance concepts are applied variety of nuclear facilities, which is, nuclear reactors, uranium enrichment plants, fuel conversion/fabrication plants, reprocessing plants, radioactive waste management facilities, and so on, considering unique features of each facility.

Software Quality Assurance for Nuclear Safety Systems

International Nuclear Information System (INIS)

Sparkman, D R; Lagdon, R

2004-01-01

-critical software and applies the highest level of rigor for those systems. DOE has further defined a risk approach to nuclear safety system software consistent with the analyses required for operation of nuclear facilities. This requires the grading of software in terms of safety class and safety significant structures, systems and components (SSCs). Safety-class SSCs are related to public safety where as safety-significant SSCs are identified for specific aspects of defense-in-depth and worker safety. Industry standards do not directly categorize nuclear safety software and DOE sites are not consistent in their approach to nuclear safety software quality assurance. DOE is establishing a more detailed graded approach for software associated with safety class and safety significant systems. This paper presents the process and results that DOE utilized to develop a detailed classification scheme for nuclear safety software

[Psychometric assessment of defense mechanisms: correlation between questionnaire and expert rating. Initial study of validity].

Science.gov (United States)

Reister, G; Fellhauer, R F; Franz, M; Wirth, T; Schellberg, D; Schepank, H; Tress, W

1993-01-01

Within the limits of an epidemiological longitudinal field survey on prevalence and course of psychogenic disorders a high-risk-population suffering from medical psychogenic impairment was investigated. The study was conducted in order to verify an etiological multi-level-model of psychogenic disorders in relation to the socialempiric variables "critical life events" and "social support" as well as the depth psychological oriented construct "personality". Besides other instruments a self rating scale based on Vallant's hierarchical model of defense, i.e. the german adaptation of the DSQ (Defense Style Questionnaire) of Bond and coworkers, was used for the accurate measurement of relevant personality parameters. Although defense processes predominantly work unconscious, manifestations of defense mechanisms could be measured indirectly by means of the rating scale. Its essential dimensions separated clinical patients from a group of healthy controls. Furthermore an immature organisation of defense was found to be related to psychogenic impairment. Concerning self- and expert-rating a significant correlation between "immature defense" and the defense mechanisms "schizoid phantasy", "projection" and "acting out" was proved.

Problems and Mitigation Strategies for Developing and Validating Statistical Cyber Defenses

Science.gov (United States)

2014-04-01

such as Firewalls , HTTP proxies, and application-level Attribute Based Ac- cess Control [1] to provide a layered defense in depth. The spe- cific...research and technology develop- ment in several areas including: cyber defense, synthetic biology, advanced design tools, AI learning, and quantum

Defense islands in bacterial and archaeal genomes and prediction of novel defense systems.

Science.gov (United States)

Makarova, Kira S; Wolf, Yuri I; Snir, Sagi; Koonin, Eugene V

2011-11-01

The arms race between cellular life forms and viruses is a major driving force of evolution. A substantial fraction of bacterial and archaeal genomes is dedicated to antivirus defense. We analyzed the distribution of defense genes and typical mobilome components (such as viral and transposon genes) in bacterial and archaeal genomes and demonstrated statistically significant clustering of antivirus defense systems and mobile genes and elements in genomic islands. The defense islands are enriched in putative operons and contain numerous overrepresented gene families. A detailed sequence analysis of the proteins encoded by genes in these families shows that many of them are diverged variants of known defense system components, whereas others show features, such as characteristic operonic organization, that are suggestive of novel defense systems. Thus, genomic islands provide abundant material for the experimental study of bacterial and archaeal antivirus defense. Except for the CRISPR-Cas systems, different classes of defense systems, in particular toxin-antitoxin and restriction-modification systems, show nonrandom clustering in defense islands. It remains unclear to what extent these associations reflect functional cooperation between different defense systems and to what extent the islands are genomic "sinks" that accumulate diverse nonessential genes, particularly those acquired via horizontal gene transfer. The characteristics of defense islands resemble those of mobilome islands. Defense and mobilome genes are nonrandomly associated in islands, suggesting nonadaptive evolution of the islands via a preferential attachment-like mechanism underpinned by the addictive properties of defense systems such as toxins-antitoxins and an important role of horizontal mobility in the evolution of these islands.

Assessment of the factors with significant influence on safety culture

International Nuclear Information System (INIS)

Farcasiu, M.; Nitoi, M.

2013-01-01

In this paper, a qualitative and a quantitative evaluation of the factors with significant impact on safety culture were performed. These techniques were established and applied in accordance with IAEA standards. In order to show the applicability and opportunity of the methodology a specific case study was prepared: safety culture evaluation for INR Pitesti. The qualitative evaluation was performed using specific developed questionnaires. Through analysis of the completed questionnaires was established the development stage of safety culture at INR. The quantitative evaluation was performed using a guide to rate the influence factors. For each factor was identified the influence (negative or positive) and ranking score was estimated using scoring criteria. The results have emphasized safety culture stages. The paper demonstrates the fact that using both quantitative and qualitative assessment techniques, a practical value of the safety culture concept is given. (authors)

MicroRNA-Mediated Gene Silencing in Plant Defense and Viral Counter-Defense

Directory of Open Access Journals (Sweden)

Sheng-Rui Liu

2017-09-01

Full Text Available MicroRNAs (miRNAs are non-coding RNAs of approximately 20–24 nucleotides in length that serve as central regulators of eukaryotic gene expression by targeting mRNAs for cleavage or translational repression. In plants, miRNAs are associated with numerous regulatory pathways in growth and development processes, and defensive responses in plant–pathogen interactions. Recently, significant progress has been made in understanding miRNA-mediated gene silencing and how viruses counter this defense mechanism. Here, we summarize the current knowledge and recent advances in understanding the roles of miRNAs involved in the plant defense against viruses and viral counter-defense. We also document the application of miRNAs in plant antiviral defense. This review discusses the current understanding of the mechanisms of miRNA-mediated gene silencing and provides insights on the never-ending arms race between plants and viruses.

Knee Kinetics during Squats of Varying Loads and Depths in Recreationally Trained Females.

Science.gov (United States)

Flores, Victoria; Becker, James; Burkhardt, Eric; Cotter, Joshua

2018-03-06

The back squat exercise is typically practiced with varying squat depths and barbell loads. However, depth has been inconsistently defined, resulting in unclear safety precautions when squatting with loads. Additionally, females exhibit anatomical and kinematic differences to males which may predispose them to knee joint injuries. The purpose of this study was to characterize peak knee extensor moments (pKEMs) at three commonly practiced squat depths of above parallel, parallel, and full depth, and with three loads of 0% (unloaded), 50%, and 85% depth-specific one repetition maximum (1RM) in recreationally active females. Nineteen females (age, 25.1 ± 5.8 years; body mass, 62.5 ± 10.2 kg; height, 1.6 ± 0.10 m; mean ± SD) performed squats of randomized depth and load. Inverse dynamics were used to obtain pKEMs from three-dimensional knee kinematics. Depth and load had significant interaction effects on pKEMs (p = 0.014). Significantly greater pKEMs were observed at full depth compared to parallel depth with 50% 1RM load (p = 0.001, d = 0.615), and 85% 1RM load (p = 0.010, d = 0.714). Greater pKEMs were also observed at full depth compared to above parallel depth with 50% 1RM load (p = 0.003, d = 0.504). Results indicate effect of load on female pKEMs do not follow a progressively increasing pattern with either increasing depth or load. Therefore, when high knee loading is a concern, individuals are must carefully consider both the depth of squat being performed and the relative load they are using.

29 CFR 1630.15 - Defenses.

Science.gov (United States)

2010-07-01

... safety of the individual or others in the workplace. (See § 1630.2(r) defining direct threat.) (c) Other...) Conflict with other Federal laws. It may be a defense to a charge of discrimination under this part that a...

Defense styles of pedophilic offenders.

Science.gov (United States)

Drapeau, Martin; Beretta, Véronique; de Roten, Yves; Koerner, Annett; Despland, Jean-Nicolas

2008-04-01

This pilot study investigated the defense styles of pedophile sexual offenders. Interviews with 20 pedophiles and 20 controls were scored using the Defense Mechanisms Rating Scales. Results showed that pedophiles had a significantly lower overall defensive functioning score than the controls. Pedophiles used significantly fewer obsessional-level defenses but more major image-distorting and action-level defenses. Results also suggested differences in the prevalence of individual defenses where pedophiles used more dissociation, displacement, denial, autistic fantasy, splitting of object, projective identification, acting out, and passive aggressive behavior but less intellectualization and rationalization.

Role of the Regulatory Body in Implementing Defence in Depth in Nuclear Installations - Regulatory Oversight in Egypt

Energy Technology Data Exchange (ETDEWEB)

El-Sheikh, B. M., E-mail: badawymel@yahoo.com [Egyptian Nuclear and Radiological Regulatory Authority Cairo (Egypt)

2014-10-15

The fundamental objective of all nuclear safety regulatory bodies is to ensure that nuclear facilities are operated at all times in an acceptably safe manner including the safe conduct of decommissioning activities. Defence in depth is recognized as one of the fundamental safety principles that underlie the safety of nuclear power plants. Defence in depth is implemented to provide a graded protection against a wide variety of transients, incidents and accidents, including equipment failures and human errors within nuclear power plants and events initiated outside plants. The Regulator Body plays an important role in implementing defence in depth in nuclear installations in the context of a clear allocation of responsibilities with an operating organization. This role starting with setting safety objectives and by its own independent review and technical assessment of the safety justifications provided by the operating organization in addition to safety culture investigating within relevant organizations. This paper briefly reviews this role in normal operation and post accidents, and its effects on overall nuclear safety in nuclear installations with reference to Egyptian regulatory oversight. (author)

Induction of defensive enzymes (isozymes) during defense against ...

African Journals Online (AJOL)

user

2012-09-06

Sep 6, 2012 ... defense against two different fungal pathogens in pear calli ... study the biochemical changes in relation to plant defense ... relatively easy to manipulate by empirical means, allowing for a ... earlier phase, and the degree of rot was significantly ..... resistance of fruit, and they play an important role in the.

Guidance on the implementation of a risk based safety performance monitoring system for nuclear power plants

International Nuclear Information System (INIS)

Sewell, R.T.; Kuritzky, A.S.; Khatib-Rahbar, M.

1997-05-01

The principal objective of the present study is to review and evaluate existing Performance Indicator (PI) monitoring programs, and to develop and demonstrate an overall PSA-based methodology and framework for the monitoring and use of risk-based PIs and SIs (Safety Indicator), that would enable: Identification of trends and patterns in safety performance at a specific plant and a population of plants; Assessment of the significance of the trends and patterns; Identification of precursors of accident sequences and safety reductions; Identification of the most critical functional areas of concern, especially as they relate to a defense-in-depth safety philosophy; Comparison of safety performance trends at a plant with those at comparable plants; Incorporation of the PIs and SIs into a risk- and performance-based decision process. To support the overall project objective, it is important that information needs and data collection procedures are clearly outlined. Of key significance in this regard is the premise that a performance monitoring system should not be burdened by an excessive number of low-level PIs that may have only a peripheral relationship to safety. Other supporting objectives of the study include: To identify and discuss other issues pertaining to the practical implementation of a safety performance monitoring system (outlining the databases and algorithms needed); and to demonstrate implementation of the preliminary guidance for monitoring and use of the selected set of PIs and SIs, within the proposed framework, via application to the operating history of a NPP having a PSA and readily available event data

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

Yearly program of safety research for nuclear facilities and others

International Nuclear Information System (INIS)

1987-01-01

The development of FBRs in Japan has steadily progressed, and subsequently to the experimental reactor 'Joyo' and the prototype reactor 'Monju', by promoting the construction of a demonstration reactor, the stage of verifying and acquiring skill of the electricity generation plant technology of practical scale, improving the performance and establishing the economical efficiency is about to begin. The development of FBRs in Japan has been advanced independently as a national project, and the method of preventing accidents in the actual reactors has been thoroughly taken. 'On the way of thinking in the safety evaluation of FBRs' was decided by the Nuclear Safety Commission. When the safety research from 1987 is systematized, as the constituents of safety logic, the way of thinking of the defense in depth, the way of thinking of the classification according to importance, the way of thinking of multilayer barriers against radioactive substances, and the way of thinking on severe accidents were investigated. The research concerning the decision of safety design and evaluation policy, and the safety research regarding accident prevention and relaxation, accident evaluation and severe accidents are reported. (Kako, I.)

Some practical examples of defence in depth analysis for category IV gamma irradiators

International Nuclear Information System (INIS)

Rodrigues Junior, Ary de Araujo

2014-01-01

The Defence in Depth concept provides a major contribution to the safety philosophy of irradiation facilities. But problems occur when somebody tries to understand or analyse a safety system or develop a new one because there is a lack of practical examples in Safety Series 107 or other IAEA (International Atomic Energy Agency) publications for irradiation facilities. This paper tries to fill this lack of information by providing a series of practical examples and explanations about Defence in Depth concepts. (author)

Some practical examples of defence in depth analysis for category IV gamma irradiators

Energy Technology Data Exchange (ETDEWEB)

Rodrigues Junior, Ary de Araujo, E-mail: aryarj@ig.com.br [Universidade Estadual de Maringa (UEM), Maringa, PR (Brazil). Dept. de Fisica

2014-07-01

The Defence in Depth concept provides a major contribution to the safety philosophy of irradiation facilities. But problems occur when somebody tries to understand or analyse a safety system or develop a new one because there is a lack of practical examples in Safety Series 107 or other IAEA (International Atomic Energy Agency) publications for irradiation facilities. This paper tries to fill this lack of information by providing a series of practical examples and explanations about Defence in Depth concepts. (author)

Safety Oversight of Decommissioning Activities at DOE Nuclear Sites

International Nuclear Information System (INIS)

Zull, Lawrence M.; Yeniscavich, William

2008-01-01

The Defense Nuclear Facilities Safety Board (Board) is an independent federal agency established by Congress in 1988 to provide nuclear safety oversight of activities at U.S. Department of Energy (DOE) defense nuclear facilities. The activities under the Board's jurisdiction include the design, construction, startup, operation, and decommissioning of defense nuclear facilities at DOE sites. This paper reviews the Board's safety oversight of decommissioning activities at DOE sites, identifies the safety problems observed, and discusses Board initiatives to improve the safety of decommissioning activities at DOE sites. The decommissioning of former defense nuclear facilities has reduced the risk of radioactive material contamination and exposure to the public and site workers. In general, efforts to perform decommissioning work at DOE defense nuclear sites have been successful, and contractors performing decommissioning work have a good safety record. Decommissioning activities have recently been completed at sites identified for closure, including the Rocky Flats Environmental Technology Site, the Fernald Closure Project, and the Miamisburg Closure Project (the Mound site). The Rocky Flats and Fernald sites, which produced plutonium parts and uranium materials for defense needs (respectively), have been turned into wildlife refuges. The Mound site, which performed R and D activities on nuclear materials, has been converted into an industrial and technology park called the Mound Advanced Technology Center. The DOE Office of Legacy Management is responsible for the long term stewardship of these former EM sites. The Board has reviewed many decommissioning activities, and noted that there are valuable lessons learned that can benefit both DOE and the contractor. As part of its ongoing safety oversight responsibilities, the Board and its staff will continue to review the safety of DOE and contractor decommissioning activities at DOE defense nuclear sites

Performance Analysis and Optimal Allocation of Layered Defense M/M/N Queueing Systems

Directory of Open Access Journals (Sweden)

Longyue Li

2016-01-01

Full Text Available One important mission of strategic defense is to develop an integrated layered Ballistic Missile Defense System (BMDS. Motivated by the queueing theory, we presented a work for the representation, modeling, performance simulation, and channels optimal allocation of the layered BMDS M/M/N queueing systems. Firstly, in order to simulate the process of defense and to study the Defense Effectiveness (DE, we modeled and simulated the M/M/N queueing system of layered BMDS. Specifically, we proposed the M/M/N/N and M/M/N/C queueing model for short defense depth and long defense depth, respectively; single target channel and multiple target channels were distinguished in each model. Secondly, we considered the problem of assigning limited target channels to incoming targets, we illustrated how to allocate channels for achieving the best DE, and we also proposed a novel and robust search algorithm for obtaining the minimum channel requirements across a set of neighborhoods. Simultaneously, we presented examples of optimal allocation problems under different constraints. Thirdly, several simulation examples verified the effectiveness of the proposed queueing models. This work may help to understand the rules of queueing process and to provide optimal configuration suggestions for defense decision-making.

Development of Safety Significance Evaluation Program for Accidents and Events in NPPs

International Nuclear Information System (INIS)

Yang, Hui Chang; Hong, Seok Jin; Cho, Nam Chul; Chung, Dae Wook; Lee, Chang Joo

2010-01-01

To evaluate the significance in terms of safety for the accidents and events occurred in nuclear power plants using probabilistic safety assessment techniques can provide useful insights to the regulator. Based on the quantified risk information of accident or event occurred, regulators can decide which regulatory areas should be focused than the others. To support these regulatory analysis activities, KINS-ASP program was developed. KINS-ASP program can supports the risk increase due to the occurred accidents or events by providing the graphic interfaces and linked quantification engines for the PSA experts and non- PSA acquainted regulators both

Evolutionary approaches for the safety evaluation of the nuclear fuel cycle facilities: lessons learnt from french experiences and assessment of future challenges

International Nuclear Information System (INIS)

Greneche, D.

2007-01-01

This paper is aimed at presenting the recent work carried out in France on the evolution of the safety of the nuclear fuel cycle facilities (FCF). 5 main categories of FCF have been dealt with in this article: uranium conversion, uranium enrichment, fresh fuel fabrication (including Mox fuel), spent fuel storage, and spent fuel reprocessing. The specific of FCF are reviewed and it appears that FCF have generally a safety advantage over reactors: the relatively slow evolution of physico-chemical phenomena causing severe accident conditions. Generally speaking, nuclear safety is ensured through the combination of actions taken at 4 levels: design, implementation, operation and inspection. It must be underlined that the French safety analysis process is primarily based on a deterministic approach (itself based on the fundamental principle of defense-in-depth), supplemented if necessary with probabilistic safety assessment (PSA) to detect potential weak points in a nuclear facility. All this process is well implemented in reactors but in the case of FCF it is generally limited to the deterministic approach. It is showed that the approaches and general principles implemented in the safety analysis of reactors apply well to FCF but the probabilistic analysis of safety remains nevertheless little practiced in FCF for which they still require significant developments. (A.C.)

Accident management-defence in depth in Indian PHWRS

International Nuclear Information System (INIS)

Jagannad, V.B.L.; Reddy, V.V.; Hajela, Sameer; Bhatia, C.M.; Nair, Suma

2015-01-01

Defence in Depth (DiD) is the established safety principle for the design of Nuclear Power Plants (NPPs). Accident at Fukushima Dai-ichi had highlighted the importance of provisions at Level-4 and 5 of DiD. Post Fukushima accident, on-site measures have been strengthened for Indian Nuclear Power Plants. On procedural front, Accident Management Guidelines have been introduced to handle events more severe than design basis accidents. This paper elaborates enhancement of Defence in Depth provisions for Indian Nuclear Power Plants. (author)

Priming of antiherbivore defensive responses in plants

Institute of Scientific and Technical Information of China (English)

Jinwon Kim; Gary W.Felton

2013-01-01

Defense priming is defined as increased readiness of defense induction.A growing body of literature indicates that plants (or intact parts of a plant) are primed in anticipation of impending environmental stresses,both biotic and abiotic,and upon the following stimulus,induce defenses more quickly and strongly.For instance,some plants previously exposed to herbivore-inducible plant volatiles (HIPVs) from neighboring plants under herbivore attack show faster or stronger defense activation and enhanced insect resistance when challenged with secondary insect feeding.Research on priming of antiherbivore defense has been limited to the HIPV-mediated mechanism until recently,but significant advances were made in the past three years,including non-HIPV-mediated defense priming,epigenetic modifications as the molecular mechanism of priming,and others.It is timely to consider the advances in research on defense priming in the plantinsect interactions.

Safety assessment of the liquid-fed ceramic melter process

International Nuclear Information System (INIS)

Buelt, J.L.; Partain, W.L.

1980-08-01

As part of its development program for the solidification of high-level nuclear waste, Pacific Northwest Laboratory assessed the safety issues for a complete liquid-fed ceramic melter (LFCM) process. The LFCM process, an adaption of commercial glass-making technology, is being developed to convert high-level liquid waste from the nuclear fuel cycle into glass. This safety assessment uncovered no unresolved or significant safety problems with the LFCM process. Although in this assessment the LFCM process was not directly compared with other solidification processes, the safety hazards of the LFCM process are comparable to those of other processes. The high processing temperatures of the glass in the LFCM pose no additional significant safety concerns, and the dispersible inventory of dried waste (calcine) is small. This safety assessment was based on the nuclear power waste flowsheet, since power waste is more radioactive than defense waste at the time of solidification, and all accident conditions for the power waste would have greater radiological consequences than those for defense waste. An exhaustive list of possible off-standard conditions and equipment failures was compiled. These accidents were then classified according to severity of consequence and type of accident. Radionuclide releases to the stack were calculated for each group of accidents using conservative assumptions regarding the retention and decontamination features of the process and facility. Two recommendations that should be considered by process designers are given in the safety assessment

Knee Joint Kinetics in Relation to Commonly Prescribed Squat Loads and Depths

Science.gov (United States)

Cotter, Joshua A.; Chaudhari, Ait M.; Jamison, Steve T.; Devor, Steven T.

2014-01-01

Controversy exists regarding the safety and performance benefits of performing the squat exercise to depths beyond 90° of knee flexion. Our aim was to compare the net peak external knee flexion moments (pEKFM) experienced over typical ranges of squat loads and depths. Sixteen recreationally trained males (n = 16; 22.7 ± 1.1 yrs; 85.4 ± 2.1 kg; 177.6 ± 0.96 cm; mean ± SEM) with no previous lower limb surgeries or other orthopedic issues and at least one year of consistent resistance training experience while utilizing the squat exercise performed single repetition squat trials in a random order at squat depths of above parallel, parallel, and below parallel. Less than one week before testing, one repetition maximum (1RM) values were found for each squat depth. Subsequent testing required subjects to perform squats at the three depths with three different loads: unloaded, 50% 1RM, and 85% 1RM (nine total trials). Force platform and kinematic data were collected to calculate pEKFM. To assess differences among loads and depths, a two-factor (load and depth) repeated-measures ANOVA with significance set at the P Squat 1RM significantly decreased 13.6% from the above parallel to parallel squat and another 3.6% from the parallel to the below parallel squat (P squat depth and load were increased (P ≤ 0.02). Slopes of pEKFM were greater from unloaded to 50% 1RM than when progressing from 50% to 85% 1RM (P squat loads used with increasing depths are not enough to offset increases in pEKFM. PMID:23085977

Approaches to safety, environment and regulatory approval for the International Thermonuclear Experimental Reactor

International Nuclear Information System (INIS)

Saji, G.; Bartels, H.W.; Chuyanov, V.; Holland, D.; Kashirski, A.V.; Morozov, S.I.; Piet, S.J.; Poucet, A.; Raeder, J.; Rebut, P.H.; Topilski, L.N.

1995-01-01

International Thermonuclear Experimental Reactor (ITER) Engineering Design Activities (EDA) in safety and environment are approaching the point where conceptual safety design, topic studies and research will give way to project oriented engineering design activities. The Joint Central Team (JCT) is promoting safety design and analysis necessary for siting and regulatory approval. Scoping studies are underway at the general level, in terms of laying out the safety and environmental design framework for ITER. ITER must follow the nuclear regulations of the host country as the future construction site of ITER. That is, regulatory approval is required before construction of ITER. Thus, during the EDA, some preparations are necessary for the future application for regulatory approval. Notwithstanding the future host country's jurisdictional framework of nuclear regulations, the primary responsibility for safety and reliability of ITER rests with the legally responsible body which will operate ITER. Since scientific utilization of ITER and protection of the large investment depends on safe and reliable operation of ITER, we are highly motivated to achieve maximum levels of operability, maintainability, and safety. ITER will be the first fusion facility in which overall 'nuclear safety' provisions need to be integrated into the facility. For example, it will be the first fusion facility with significant decay heat and structural radiational damage. Since ITER is an experimental facility, it is also important that necessary experiments can be performed within some safety design limits without requiring extensive regulatory procedures. ITER will be designed with such a robust safety envelope compatible with the fusion power and the energy inventories. The basic approach to safety will be realized by 'defense-in-depth'. (orig.)

Operating experience feedback from safety significant events at research reactors

Energy Technology Data Exchange (ETDEWEB)

Shokr, A.M. [Atomic Energy Authority, Abouzabal (Egypt). Egypt Second Research Reactor; Rao, D. [Bhabha Atomic Research Centre, Mumbai (India)

2015-05-15

Operating experience feedback is an effective mechanism to provide lessons learned from the events and the associated corrective actions to prevent recurrence of events, resulting in improving safety in the nuclear installations. This paper analyzes the events of safety significance that have been occurred at research reactors and discusses the root causes and lessons learned from these events. Insights from literature on events at research reactors and feedback from events at nuclear power plants that are relevant to research reactors are also presented along with discussions. The results of the analysis showed the importance of communication of safety information and exchange of operating experience are vital to prevent reoccurrences of events. The analysis showed also the need for continued attention to human factors and training of operating personnel, and the need for establishing systematic ageing management programmes of reactor facilities, and programmes for safety management of handling of nuclear fuel, core components, and experimental devices.

Operating experience feedback from safety significant events at research reactors

International Nuclear Information System (INIS)

Shokr, A.M.

2015-01-01

Operating experience feedback is an effective mechanism to provide lessons learned from the events and the associated corrective actions to prevent recurrence of events, resulting in improving safety in the nuclear installations. This paper analyzes the events of safety significance that have been occurred at research reactors and discusses the root causes and lessons learned from these events. Insights from literature on events at research reactors and feedback from events at nuclear power plants that are relevant to research reactors are also presented along with discussions. The results of the analysis showed the importance of communication of safety information and exchange of operating experience are vital to prevent reoccurrences of events. The analysis showed also the need for continued attention to human factors and training of operating personnel, and the need for establishing systematic ageing management programmes of reactor facilities, and programmes for safety management of handling of nuclear fuel, core components, and experimental devices.

Perspectives on understanding and verifying the safety terrain of modular high temperature gas-cooled reactors

Energy Technology Data Exchange (ETDEWEB)

Carlson, Donald E., E-mail: donald@carlsonperin.net [11221 Empire Lane, Rockville, MD 20852 (United States); Ball, Sydney J., E-mail: beckysyd@comcast.net [100 Greywood Place, Oak Ridge, TN 37830 (United States)

2016-09-15

The passive safety characteristics of modular high temperature gas-cooled reactors (HTGRs) are conceptually well known and are largely supported by insights from past and ongoing research. This paper offers perspectives on selected issues in areas where further analysis and testing achievable within existing research and demonstration programs could help address residual uncertainties and better support the analysis of safety performance and the regulatory assessment of defense in depth. Areas considered include the evaluation of normal and anomalous core operating conditions and the analysis of accidents involving loss of forced cooling, coolant depressurization, air ingress, moisture ingress, and reactivity events. In addition to discussing associated uncertainties and potential measures to address them, this paper also proposes supplemental “safety terrain” studies that would use realistic assessments of postulated extreme event sequences to establish a more comprehensive understanding of the inherent behaviors and ultimate safety capabilities of modular HTGRs.

Perspectives on Understanding and Verifying the Safety Terrain of Modular High Temperature Gas-Cooled Reactors

International Nuclear Information System (INIS)

Carlson, Donald E.

2014-01-01

The inherent safety characteristics of modular high temperature gas-cooled reactors (HTGRs) are conceptually well known and are largely supported by insights from past and ongoing research. This paper offers perspectives on selected issues in areas where further analysis and testing achievable within existing research and demonstration programs could help address residual uncertainties and better support the analysis of safety performance and the regulatory assessment of defense in depth. Areas considered include the evaluation of normal and anomalous core operating conditions and the analysis of accidents involving coolant depressurization, air ingress, moisture ingress, and reactivity insertion. In addition to discussing associated uncertainties and potential measures to address them, the paper also proposes supplemental “safety terrain” studies that would use realistic assessments of postulated extreme event sequences to establish a more comprehensive understanding of the inherent behaviors and ultimate safety capabilities of modular HTGRs. (author)

Complementary safety assessments of the French nuclear power plants (European 'stress tests'). Report by the French nuclear safety authority - December 2011

International Nuclear Information System (INIS)

2011-12-01

After having recalled the organisation of nuclear safety and radiation protection regulation in France, presented the French nuclear safety regulations (acts, decrees, orders, ASN decisions, rules and guides), described the nuclear safety approach in France (the 'defense in depth' concept), and ASN's sanctions powers, this report presents the French approach to complementary safety assessments (CSAs) with their different types of specifications (those consistent with European specification, those broader than the European specifications, and those which take into account some situations resulting from a malevolent act), and with the different categories of facilities concerned by these CSAs. It presents the organisation of the targeted inspections and outlines the transparency of this action and public information. Then, after an overview of the French nuclear power plant fleet, it discusses how earthquakes, flooding, and other extreme natural phenomena related to flooding are taken into account in the design of facilities and in terms of evaluation of safety margins. It describes the consequences of some critical situations (loss of electrical power supplies and cooling systems) and how they could be dealt with. It also addresses the different aspects of a severe accident management (organisation, measures, and actions to be performed) and the conditions related to the use of outside contractors

Status of nuclear safety developments and prospects for the future

International Nuclear Information System (INIS)

Birkhofer, A.; Laverie, M.

1992-01-01

During the eighties, the emphasis on safety questions progressively shifted from design and construction of plants towards the operation of existing plants. Lessons learned from incidents and accidents in national or foreign plants, experience gained from the operation and maintenance of plants, research and ageing of installations were some of the issues on which, at that time, the nuclear community focused its attention and concern. At the same time, numerous actions, dedicated to the strengthening of defense-in-depth which consists of piling up enough dispositions (or defense lines) to be able to deal with situations even beyond the initial design of plants, were implemented. Despite all these technical precautions to reduce the risk to the public and the environment, the acceptance level decreased in some countries, due to the impact of T.M.T. and Chernobyl, a certain misunderstanding between technicians and the public proceeding from a lack of openness and poor communication

Objective Provision Tree (OPT) in sodium cooled fast reactors; Objective Provision Tree (OPT) en reactores rapidos refrigerados por sodio. Aplicacion a la funcion de seguridad de evacuacion de calor residual

Energy Technology Data Exchange (ETDEWEB)

Queral, C.; Montero-Mayorga, J.; Gonzalez-Cadelo, J.

2013-07-01

Application to the safety function of residual heat removal As part of the project {sup S}afety Assessment for Reactor of GEN-IV (SARGEN IV) has been implemented the methodology ISAM from the IAEA to the safety assessment of new sodium reactor designs. Within the ISAM, a new tool to facilitate this assessment is the Objective Provision Tree (OPT) which documents the provisions necessary for each of the levels of defense in depth, as well as for each critical function of security. Due to the design innovations that have sodium reactors, the evaluation of safety and licensing of these reactors requires special considerations. In this work we have analyzed the mechanisms of failure of the safety function concerning the evacuation of waste heat, and have been proposed different provisions for each of the first three levels of defense in depth. The main result of this work is reflected in the elaboration of the OPTs, one for each of the first three levels of defense in depth for the safety of evacuation of residual heat function. These trees represent in a schematic way the provisions necessary to comply with the objectives of each level which are respectively: 1) deviations from normal operation, 2) control of abnormal operation and fault detection and 3) incidental control.

Compatibility of safety and security

International Nuclear Information System (INIS)

Jalouneix, J.

2013-01-01

Nuclear safety means the achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, the public and the environment from undue radiation hazards while nuclear security means the prevention and detection of, and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear material. Nuclear safety and nuclear security present large similarities in their aim as in their methods and are mutually complementary in the field of protection with regard to the risk of sabotage. However they show specific attributes in certain areas which leads to differences in their implementation. For instance security culture must integrate deterrence and confidentiality while safety culture implies transparency and open dialogue. Two important design principles apply identically for safety and security: the graded approach and the defense in depth. There are also strong similarities in operating provisions: -) a same need to check the availability of the equipment, -) a same need to treat the experience feedback, or -) a same need to update the basic rules. There are also strong similarities in emergency management, for instance the elaboration of emergency plans and the performance of periodic exercises. Activities related to safety of security of an installation must be managed by a quality management system. For all types of nuclear activities and facilities, a well shared safety culture and security culture is the guarantee of a safe and secure operation. The slides of the presentation have been added at the end of the paper

2004 annual report. Defense, safety, energy, information, health. CEA in the center of big European challenges; Rapport annuel 2004. Defense, securite, energie, information, sante. Le CEA au coeur des grands defis europeens

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This document is the 2004 annual report of the French atomic energy commission (CEA). It presents the R and D activities of the CEA in three main domains: 1 - defense and safety, maintaining perenniality of nuclear dissuasion and nuclear safety: supplying nuclear weapons to armies, maintaining dissuasion capability with the simulation program, sharing R and D means with the scientific community and the industrial world, designing and maintaining naval nuclear propulsion reactors, cleansing Marcoule and Pierrelatte facilities, monitoring treaties and fighting against proliferation and terrorism; 2 - energy, developing more competitive and cleaner energy sources: nuclear waste management, optimization of industrial nuclear activities, future nuclear systems and new energy technologies, basic research on energy, radiobiology and toxicology; 3 - information and health, valorizing industry thanks to technological research and supplying new tools for health and medical research: micro- and nano-technologies, software technologies, basic research for industrial innovation, nuclear technologies for health and bio-technologies. (J.S.)

Defense Islands in Bacterial and Archaeal Genomes and Prediction of Novel Defense Systems ▿†‡

Science.gov (United States)

Makarova, Kira S.; Wolf, Yuri I.; Snir, Sagi; Koonin, Eugene V.

2011-01-01

The arms race between cellular life forms and viruses is a major driving force of evolution. A substantial fraction of bacterial and archaeal genomes is dedicated to antivirus defense. We analyzed the distribution of defense genes and typical mobilome components (such as viral and transposon genes) in bacterial and archaeal genomes and demonstrated statistically significant clustering of antivirus defense systems and mobile genes and elements in genomic islands. The defense islands are enriched in putative operons and contain numerous overrepresented gene families. A detailed sequence analysis of the proteins encoded by genes in these families shows that many of them are diverged variants of known defense system components, whereas others show features, such as characteristic operonic organization, that are suggestive of novel defense systems. Thus, genomic islands provide abundant material for the experimental study of bacterial and archaeal antivirus defense. Except for the CRISPR-Cas systems, different classes of defense systems, in particular toxin-antitoxin and restriction-modification systems, show nonrandom clustering in defense islands. It remains unclear to what extent these associations reflect functional cooperation between different defense systems and to what extent the islands are genomic “sinks” that accumulate diverse nonessential genes, particularly those acquired via horizontal gene transfer. The characteristics of defense islands resemble those of mobilome islands. Defense and mobilome genes are nonrandomly associated in islands, suggesting nonadaptive evolution of the islands via a preferential attachment-like mechanism underpinned by the addictive properties of defense systems such as toxins-antitoxins and an important role of horizontal mobility in the evolution of these islands. PMID:21908672

Safety of nuclear installations. An international comparison

International Nuclear Information System (INIS)

Renner, Andrea; Diwes, Andreas; Reingardt, Martin

2010-01-01

Safeguarding of nuclear power plants against disruptive actions or other external hazards is part of the plant design and presumption of an operation license. The general principle is defense in depth involving different security zones with separate barriers. The safeguards for nuclear installations are organized in three areas of responsibility: governmental measures (police, military), technical (detectors, scanners, illuminations, camera tracking, concrete barriers) and personnel measures (access control, security personnel, alarm) of the operating company. International responsibilities results from the treaty on the non-proliferation of nuclear weapons and several IAEA documents. The authors discuss the national regulations in Germany, Switzerland, United Kingdom and USA. Older NPPs that are not in compliance with actual safety standards will be a topic of increasing importance.

Safety standards of flood defenses

NARCIS (Netherlands)

Vrijling, J.K.; Schweckendiek, T.; Kanning, W.

2011-01-01

Current design codes like the Eurocode use safety or reliability classes to assign target reliabilities to different types of structures or structural members according to the potential consequences of failure. That, in essence, is a risk-based criterion. A wide range of structures is designed with

Safety Justification and Safety Case for Safety-critical Software in Digital Reactor Protection System

International Nuclear Information System (INIS)

Kwon, Kee-Choon; Lee, Jang-Soo; Jee, Eunkyoung

2016-01-01

Nuclear safety-critical software is under strict regulatory requirements and these regulatory requirements are essential for ensuring the safety of nuclear power plants. The verification & validation (V and V) and hazard analysis of the safety-critical software are required to follow regulatory requirements through the entire software life cycle. In order to obtain a license from the regulatory body through the development and validation of safety-critical software, it is essential to meet the standards which are required by the regulatory body throughout the software development process. Generally, large amounts of documents, which demonstrate safety justification including standard compliance, V and V, hazard analysis, and vulnerability assessment activities, are submitted to the regulatory body during the licensing process. It is not easy to accurately read and evaluate the whole documentation for the development activities, implementation technology, and validation activities. The safety case methodology has been kwon a promising approach to evaluate the level and depth of the development and validation results. A safety case is a structured argument, supported by a body of evidence that provides a compelling, comprehensible, and valid case that a system is safe for a given application in a given operating environment. It is suggested to evaluate the level and depth of the results of development and validation by applying safety case methodology to achieve software safety demonstration. A lot of documents provided as evidence are connected to claim that corresponds to the topic for safety demonstration. We demonstrated a case study in which more systematic safety demonstration for the target system software is performed via safety case construction than simply listing the documents

Safety Justification and Safety Case for Safety-critical Software in Digital Reactor Protection System

Energy Technology Data Exchange (ETDEWEB)

Kwon, Kee-Choon; Lee, Jang-Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Jee, Eunkyoung [KAIST, Daejeon (Korea, Republic of)

2016-10-15

Nuclear safety-critical software is under strict regulatory requirements and these regulatory requirements are essential for ensuring the safety of nuclear power plants. The verification & validation (V and V) and hazard analysis of the safety-critical software are required to follow regulatory requirements through the entire software life cycle. In order to obtain a license from the regulatory body through the development and validation of safety-critical software, it is essential to meet the standards which are required by the regulatory body throughout the software development process. Generally, large amounts of documents, which demonstrate safety justification including standard compliance, V and V, hazard analysis, and vulnerability assessment activities, are submitted to the regulatory body during the licensing process. It is not easy to accurately read and evaluate the whole documentation for the development activities, implementation technology, and validation activities. The safety case methodology has been kwon a promising approach to evaluate the level and depth of the development and validation results. A safety case is a structured argument, supported by a body of evidence that provides a compelling, comprehensible, and valid case that a system is safe for a given application in a given operating environment. It is suggested to evaluate the level and depth of the results of development and validation by applying safety case methodology to achieve software safety demonstration. A lot of documents provided as evidence are connected to claim that corresponds to the topic for safety demonstration. We demonstrated a case study in which more systematic safety demonstration for the target system software is performed via safety case construction than simply listing the documents.

Defence in depth by 'Leittechnique' systems with graded intelligence

International Nuclear Information System (INIS)

Aleite, W.

1983-01-01

In the past, only two types of nuclear power plant instrumentation and control systems were in use in the Federal Republic of Germany (FRG): safety systems and operational systems. Present nuclear power plant 'Leittechnique' systems in the FRG have been expanded from this 'black-and-white' status to multiple-grade systems with respect to safety, qualification requirements and intelligence. The extensive experience of the past has encouraged the rule-making committees - representing all parties working in the nuclear field - to differentiate between the protection limitations and condition limitations of the reactor protection system on one hand and the information systems (including the accident monitoring and alarm system) of different safety importance on the other, assuming additional extensive application of non-safety-grade operational Leittechnique systems. These definitions of categories are in accordance with international practice and enable designers to apply 'echelons of defence', composed of equipment of all categories, in accordance with 'defence-in-depth' concepts. They also simplify the introduction of computerized equipment, especially in the lower safety categories. Status, background and reasons of the introduction, as well as typical defence-in-depth modes, of the first running Leittechnique system of this kind (in the Grafenrheinfeld nuclear power plant) and especially their different tasks in disturbance handling are described. The international situation and future developments are briefly characterized. (author)

A digest of the Nuclear Safety Division report on the Fukushima Dai-ichi accident seminar (4). Issues identified by the accident

International Nuclear Information System (INIS)

Moriyama, Kumiaki; Abe, Kiyoharu

2013-01-01

AESJ Nuclear Safety Division published 'Report on the Fukushima Dai-ichi Accident Seminar - what was wrong and what should been down in future-' which would be published as five special articles of the AESJ journal. The Fukushima Dai-ichi accident identified issues of several activities directly related with nuclear safety in the areas of safety design, severe accident management and safety regulations. PRA, operational experiences and safety research could not always contribute safety assurance of nuclear power plant so much. This article (4) summarized technical issues based on related facts of the accident as much as possible and discussed' what was wrong and what should be down in future'. Important issues were identified from defense-in-depth philosophy and lessons learned on safety design were obtained from accident progression analysis. Activities against external events and continuous improvements of safety standards based on latest knowledge were most indispensable. Strong cooperation among experts in different areas was also needed. (T. Tanaka)

Assessment of the nuclear installation's safety significant events

International Nuclear Information System (INIS)

Vidican, D.

2005-01-01

This document tries to establish, based on the available documentation, the main steps in development of Assessment of the Events in Nuclear Installations. It takes into account: selection of the safety significant occurrences, establishing the direct cause and contributors as well as the root cause and contributors. Also, the document presents the necessary corrective actions and generic lessons to be learned from the event. The document is based especially on IAEA - ASSET guidelines and DOE root cause analysis Guidance. (author)

Safety Education in Driving. 2nd Revision.

Science.gov (United States)

Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

Intended for driving instruction students, this publication contains instructional materials for safety education. It contains six sections on facts and figures; defensive driving; safety devices; restraints; emergency situations; and other highway users. Each section consists of reading material followed by an activity or activities. A total of…

Analysis approach for common cause failure on non-safety digital control system

Energy Technology Data Exchange (ETDEWEB)

Kim, Yun Goo; Oh, Eungse [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

2014-05-15

The effects of common cause failure (CCF) on safety digital instrumentation and control (I and C) system had been considered in defense in depth and diversity coping analysis with safety analysis method. For the non-safety system, single failure had been considered for safety analysis. IEEE Std. 603-1991, Clause 5.6.3.1(2), 'Isolation' states that no credible failure on the non-safety side of an isolation device shall prevent any portion of a safety system from meeting its minimum performance requirements during and following any design basis event requiring that safety function. The software CCF is one of the credible failure on the non-safety side. In advanced digital I and C system, same hardware component is used for different control system and the defect in manufacture or common external event can generate CCF. Moreover, the non-safety I and C system uses complex software for its various function and software quality assurance for the development process is less severe than safety software for the cost effective design. Therefore the potential defects in software cannot be ignored and the effect of software CCF on non-safety I and C system is needed to be evaluated. This paper proposes the general process and considerations for the analysis of CCF on non-safety I and C system.

Communication's Role in Safety Management and Performance for the Road Safety Practices

OpenAIRE

Salim Keffane (s)

2014-01-01

Communication among organizations could play an important role in increasing road safety. To get in-depth knowledge of its role, this study measured managers' and employees' perceptions of the communication's role on six safety management and performance criteria for road safety practices by conducting a survey using a questionnaire among 165 employees and 135 managers. Path analysis using AMOS-19 software shows that some of the safety management road safety practices have high correlation wi...

Nondestructive estimation of depth of surface opening cracks in concrete beams

International Nuclear Information System (INIS)

Arne, Kevin; In, Chiwon; Kurtis, Kimberly; Kim, Jin-Yeon; Jacobs, Laurence J.

2014-01-01

Concrete is one of the most widely used construction materials and thus assessment of damage in concrete structures is of the utmost importance from both a safety point of view and a financial point of view. Of particular interest are surface opening cracks that extend through the concrete cover, as this can expose the steel reinforcement bars underneath and induce corrosion in them. This corrosion can lead to significant subsequent damage in concrete such as cracking and delamination of the cover concrete as well as rust staining on the surface of concrete. Concrete beams are designed and constructed in such a way to provide crack depths up to around 13 cm. Two different types of measurements are made in-situ to estimate depths of real surface cracks (as opposed to saw-cut notches) after unloading: one based on the impact-echo method and the other one based on the diffuse ultrasonic method. These measurements are compared to the crack depth visually observed on the sides of the beams. Discussions are given as to the advantages and disadvantages of each method

Safety significance of inadvertent operation of motor-operated valves in nuclear power plants

International Nuclear Information System (INIS)

Ruger, C.J.; Higgins, J.C.; Carbonaro, J.F.; Hall, R.E.

1994-01-01

Concerns about the consequences of valve mispositioning were brought to the forefront following an event at Davis Besse in 1985. The concern related to the ability to reposition open-quotes position-changeableclose quotes motor-operated valves (MOVs) from the control room in the event of their inadvertent operation and was documented in U.S. Nuclear Regulatory Commission (USNRC) Bulletin 85-03 and Generic Letter (GL) 89-10. The mispositioned MOVs may not be able to be returned to their required position due to high differential pressure or high flow conditions across the valves. The inability to reposition such valves may have significantly safety consequences, as in the Davis Besse event. However, full consideration of such mispositioning in safety analyses and in MOV test programs can be labor intensive and expensive. Industry raised concerns that consideration of position-changeable valves under GL 89-10 would not decrease the probability of core damage to an extent that would justify licensee costs. As a response, Brookhaven National Laboratory has conducted separate scoping studies for both boiling water reactors (BWRs) and pressurized water reactors (PWRs) using probabilistic risk assessment (PRA) techniques to determine if such valve mispositioning by itself is significant to safety. The approach used internal events PRA models to survey the order of magnitude of the risk-significance of valve mispositioning by considering the failure of selected position-changeable MOVs. The change in core damage frequency was determined for each valve considered, and the results were presented as a risk increase ratio for each of four assumed MOV failure rates. The risk increase ratios resulting from this failure rate sensitivity study can be used as a basis for a determination of the risk-significance of the MOV mispositioning issues for BWRs and PWRs

Ullage Compatible Optical Sensor for Monitoring Safety Significant Malfunctions, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Significant emphasis has been placed on aircraft fuel tank safety following the TWA Flight 800 accident in July 1996. Upon investigation, the National Transportation...

Multimegawatt Space Reactor Safety

International Nuclear Information System (INIS)

Stanley, M.L.

1989-01-01

The Multimegawatt (MMW) Space Reactor Project supports the Strategic Defense Initiative Office requirement to provide reliable, safe, cost-effective, electrical power in the MMW range. Specifically, power may be used for neutral particle beams, free electron lasers, electromagnetic launchers, and orbital transfer vehicles. This power plant technology may also apply to the electrical power required for other uses such as deep-space probes and planetary exploration. The Multimegawatt Space Reactor Project, the Thermionic Fuel Element Verification Program, and Centaurus Program all support the Multimegawatt Space Nuclear Power Program and form an important part of the US Department of Energy's (DOE's) space and defense power systems activities. A major objective of the MMW project is the development of a reference flight system design that provides the desired levels of public safety, health protection, and special nuclear material (SNM) protection when used during its designated missions. The safety requirements for the MMW project are a hierarchy of requirements that consist of safety requirements/regulations, a safety policy, general safety criteria, safety technical specifications, safety design specifications, and the system design. This paper describes the strategy and philosophy behind the development of the safety requirements imposed upon the MMW concept developers. The safety organization, safety policy, generic safety issues, general safety criteria, and the safety technical specifications are discussed

Significance of FIZ Technik Databases in nuclear safety and environmental protection

International Nuclear Information System (INIS)

Das, N.K.

1993-01-01

The language of the abstracts of the FIZ Technik databases is primarly German (e.g. DOMA 80%, SDIM 70%). Furthermore FIZ Technik offers licence databases on engineering and technology, management, manufacturers, products, contacts, standards and specifications, geosciences and natural resources. The contents and structure of the databases are described in the FIZ Technik bluesheets and the database news. With some examples the significance of the FIZ Technik databases DOMA, ZDEE, SDIM, SILI and MEDI in nuclear safety and environmental protection is shown. (orig.)

Safety significance of steam generator tube degradation mechanisms

Energy Technology Data Exchange (ETDEWEB)

Roussel, G; Mignot, P [AIB-Vincotte Nuclear - AVN, Brussels (Belgium)

1991-07-01

Steam generator (SG) tube bundle is a part of the Reactor Coolant Pressure Boundary (RCPB): this means that its integrity must be maintained. However, operating experience shows various types of tube degradation to occur in the SG tubing, which may lead to SG tube leaks or SG tube ruptures and create a loss of primary system coolant through the SG, therefore providing a direct path to the environment outside the primary containment structure. In this paper, the major types of known SG tube degradations are described and analyzed in order to assess their safety significance with regard to SG tube integrity. In conclusion: The operational reliability and the safety of the PWR steam generator s requires a sufficient knowledge of the degradation mechanisms to determine the amount of degradation that a tube can withstand and the time that it may remain in operation. They also require the availability of inspection techniques to accurately detect and characterize the various degradations. The status of understanding of the major types of degradation summarized in this paper shows and justifies why efforts are being performed to improve the management of the steam generator tube defects.

Patient safety culture in China: a case study in an outpatient setting in Beijing.

Science.gov (United States)

Liu, Chaojie; Liu, Weiwei; Wang, Yuanyuan; Zhang, Zhihong; Wang, Peng

2014-07-01

To investigate the patient safety culture in an outpatient setting in Beijing and explore the meaning and implications of the safety culture from the perspective of health workers and patients. A mixed methods approach involving a questionnaire survey and in-depth interviews was adopted. Among the 410 invited staff members, 318 completed the Hospital Survey of Patient Safety Culture (HSOPC). Patient safety culture was described using 12 subscale scores. Inter-subscale correlation analysis, ANOVA and stepwise multivariate regression analyses were performed to identify the determinants of the patient safety culture scores. Interviewees included 22 patients selected through opportunity sampling and 27 staff members selected through purposive sampling. The interview data were analysed thematically. The survey respondents perceived high levels of unsafe care but had personally reported few events. Lack of 'communication openness' was identified as a major safety culture problem, and a perception of 'penalty' was the greatest barrier to the encouragement of error reporting. Cohesive 'teamwork within units', while found to be an area of strength, conversely served as a protective and defensive mechanism for medical practice. Low levels of trust between providers and consumers and lack of management support constituted an obstacle to building a positive patient safety culture. This study in China demonstrates that a punitive approach to error is still widespread despite increasing awareness of unsafe care, and managers have been slow in acknowledging the importance of building a positive patient safety culture. Strong 'teamwork within units', a common area of strength, could fuel the concealment of errors. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

LFR safety approach and main ELFR safety analysis results

International Nuclear Information System (INIS)

Bubelis, E.; Schikorr, M.; Frogheri, M.; Mansani, L.; Bandini, G.; Burgazzi, L.; Mikityuk, K.; Zhang, Y.; Lo Frano, R.; Forgione, N.

2013-01-01

LFR safety approach: → A global safety approach for the LFR reference plant has been assessed and the safety analyses methodology has been developed. → LFR follows the general guidelines of the Generation IV safety concept recommendations. Thus, improved safety and higher reliability are recognized as an essential priority. → The fundamental safety objectives and the Defence-in-Depth (DiD) approach, as described by IAEA Safety Guides, have been preserved. → The recommendations of the Risk and Safety Working Group (RSWG) of GEN-IV IF has been taken into account: • safety is to be “built-in” in the fundamental design rather than “added on”; • full implementation of the Defence-in-Depth principles in a manner that is demonstrably exhaustive, progressive, tolerant, forgiving and well-balanced; • “risk-informed” approach - deterministic approach complemented with a probabilistic one; • adoption of an integrated methodology that can be used to evaluate and document the safety of Gen IV nuclear systems - ISAM. In particular the OPT tool is the fundamental methodology used throughout the design process

Inherent and passive safety measures in accelerator driven systems: a safety strategy for ADS

International Nuclear Information System (INIS)

Maschek, W.; Rineiski, A.; Morita, K.; Flad, M.

2001-01-01

The efficiency of Accelerator Driven Systems (ADSs) for the transmutation and incineration of nuclear waste is strongly related to the utilization of so-called dedicated fuels. In the ideal case these fuels should consist of pure TRUs without fertile materials as 238 U or 232 Th to achieve highest incineration/transmutation rates. Dedicated fuels still have to be developed and programs are under way for their fabrication, irradiation and testing. These fertile-free fuels may suffer from deteriorated thermal or thermo-mechanical properties, as a reduced melting point, reduced thermal conductivity or even thermal instability. First analyses have shown that the use of dedicated fuels may lead to a strong deterioration of the safety parameters of the reactor core as e.g. the void worth, the Doppler or the kinetics quantities as neutron generation time and β eff . In addition, a dedicated core may contain multiple ''critical'' fuel masses, resulting in a considerable recriticality potential. Current knowledge on these dedicated fuels suggests that ''critical'' reactors may not be feasible, because of safety reasons. However, for ADSs, the salient hope has been promoted that due to the subcriticality of the system the poor safety features of such fuels could be coped with. Analyses are presented which show potential safety problems for such dedicated cores. Respecting the results of these analyses a safety strategy is proposed along the lines of defense approach in analogy with ideas formerly developed for fast reactors. Inherent and passive safety measures are integrated into the various defense lines. (author)

A quantitative approach for risk-informed safety significance categorization in option-2

International Nuclear Information System (INIS)

Ha, Jun Su; Seong, Poong Hyun

2004-01-01

OPTION-2 recommends that Structures, Systems, or Components (SSCs) of Nuclear Power Plants (NPPs) should be categorized into four groups according to their safety significance as well as whether they are safety-related or not. With changes to the scope of SSCs covered by 10 CFR 50, safety-related components which categorized into low safety significant SSC (RISC-3 SSC) can be exempted from the existing conservative burden (or requirements). As OPTION-2 paradigm is applied, a lot of SSCs may be categorized into RISC-3 SSCs. Changes in treatment of the RISC-3 SSCs will be recommended and then finally the recommended changes shall be evaluated. Consequently, before recommending the changes in treatment, probable candidate SSCs for the changes in treatment need to be identified for efficient risk-informed regulation and application (RIRA). Hence, in this work, a validation focused on the RISC-3 SSCs is proposed to identify probable candidate SSCs. Burden to Importance Ratio (BIR) is utilized as a quantitative measure for the validation. BIR is a measure representing the extent of resources or requirements imposed on a SSC with respect to the value of the importance measure of the SSC. Therefore SSCs having high BIR can be considered as probable candidate SSCs for the changes in treatment. In addition, the final decision whether RISC-3 SSCs can be considered as probable candidate SSCs or not should be made by an expert panel. For the effective decision making, a structured mathematical decision-making process is constructed based on Belief Networks (BBN) to overcome demerits of conventional group meeting based on unstructured discussion for decision-making. To demonstrate the usefulness of the proposed approach, the approach is applied to 22 components selected from 512 In-Service Test (IST) components of Ulchin unit 3. The results of the application show that the proposed approach can identify probable candidate SSCs for changes in treatment. The identification of the

Antiviral Defense Mechanisms in Honey Bees

Science.gov (United States)

Brutscher, Laura M.; Daughenbaugh, Katie F.; Flenniken, Michelle L.

2015-01-01

Honey bees are significant pollinators of agricultural crops and other important plant species. High annual losses of honey bee colonies in North America and in some parts of Europe have profound ecological and economic implications. Colony losses have been attributed to multiple factors including RNA viruses, thus understanding bee antiviral defense mechanisms may result in the development of strategies that mitigate colony losses. Honey bee antiviral defense mechanisms include RNA-interference, pathogen-associated molecular pattern (PAMP) triggered signal transduction cascades, and reactive oxygen species generation. However, the relative importance of these and other pathways is largely uncharacterized. Herein we review the current understanding of honey bee antiviral defense mechanisms and suggest important avenues for future investigation. PMID:26273564

Safety of CANDU nuclear power stations

International Nuclear Information System (INIS)

Snell, V.G.

1978-11-01

A nuclear plant contains a large amount of radioactive material which could be a potential threat to public health. The plant is therefore designed, built and operated so that the risk to the public is low. Careful design of the normal reactor systems is the first line of defense. These systems are highly resistant to an accident happening in the first place, and can also be effective in stopping it if it does happen. Independent and redundant safety sytems minimize the effects of an accident, or stop it completely. They include shutdown systems, emergency core cooling systems, and containment systems. Massive impairment of any one safety system together with an accident can be tolerated. This 'defence in depth' approach recognizes that men and machines are imperfect and that the unexpected happens. The nuclear power plant need not be perfect to be safe. To allow meaningful judgements we must know how safe the plant is. The Atomic Energy Control Board guidelines give one such measure, but they may overestimate the true risk. We interpret these guidelines as an upper limit to the total risk, and trace their evolution. (author)

Safety and security aspects in design of digital safety I and C in nuclear power plants

International Nuclear Information System (INIS)

Ding, Yongjian; Waedt, Karl

2016-01-01

The paper describes a safety objective oriented systematic design approach of digital (computerized) safety I and C in modern nuclear power plants which considers the plant safety requirements as well as cybersecurity needs. The defence in depth philosophy is applied by using different defence lines in the I and C architecture and protection zones in the plant IT environment.

Safety and security aspects in design of digital safety I and C in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Ding, Yongjian [University of Applied Sciences Magdeburg-Stendal, Magdeburg (Germany). Inst. of Electrical Engineering; Waedt, Karl [Areva GmbH, Erlangen (Germany). PEAS-G

2016-05-15

The paper describes a safety objective oriented systematic design approach of digital (computerized) safety I and C in modern nuclear power plants which considers the plant safety requirements as well as cybersecurity needs. The defence in depth philosophy is applied by using different defence lines in the I and C architecture and protection zones in the plant IT environment.

Light Water Reactor (LWR) safety

International Nuclear Information System (INIS)

Sehgal, Bal Raj

2006-01-01

In this paper, a historical review of the developments in the safely of LWR power plants is presented. The paper reviews the developments prior to the TMI-2 accident, i.e. the concept of the defense in depth, the design basis, the large LOCA technical controversies and the LWR safety research programs. The TMI-2 accident, which became a turning point in the history of the development of nuclear power is described briefly. The Chernobyl accident, which terrified the world and almost completely curtailed the development of nuclear power is also described briefly. The great international effort of research in the LWR design-base and severe accidents, which was, respectively, conducted prior to and following the TMI-2 and Chernobyl accidents is described next. We conclude that with the knowledge gained and the improvements in plant organisation/management and in the training of the staff at the presently-installed nuclear power stations, the LWR plants have achieved very high standards of safety and performance. The Generation 3 + LWR power plants, next to be installed, may claim to have reached the goal of assuring the safety of the public to a very large extent. This review is based on the historical developments in LWR safety that occurred primarily in USA. however, they are valid for the rest of the Western World. This review can not do justice to the many many fine contributions that have been made over the last fifty years to the cause of LWR safety. We apologize if we have not mentioned them. We also apologize for not providing references to many of the fine investigations, which have contributed towards LWR safety earning the conclusions that we describe just above

Inclusion of Premeditated Threats in the Safety Methodology for NPPs

International Nuclear Information System (INIS)

Levanon, I.

2014-01-01

classical one are: • Rate of change of the threat; • Design Basis Threat (DBT) and beyond it, including Defense in Depth (DID); • State and licensee responsibility; • Probabilistic Safety Assessment. These key issues are discussed below in light of the above two postulates and related publications, mainly of the US NRC (Nuclear Regulatory Commission). Problems are detailed and partial solutions are suggested

Enforcement actions: significant actions resolved. Quarterly progress report, July-September 1982

International Nuclear Information System (INIS)

1982-10-01

This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July to September 1982) and includes copies of letters, notices, and orders sent by the Nuclear Regulatory Commission to the licensee with respect to the enforcement action. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, in the interest of promoting public health and safety as well as common defense and security. This publication is issued on a quarterly basis to include significant enforcement actions resolved during the preceding quarter

Critical Reflections on Conservatism in Nuclear Safety Regulation

International Nuclear Information System (INIS)

Choi, Young Sung; Choi, Kwang Sik

2007-01-01

A recent report published by the Committee on Nuclear Regulatory Activities (CNRA) of the OECD Nuclear Energy Agency (NEA) says that a fundamental principle for safety regulators is the practice of conservative decision making. Nuclear regulators frequently face challenging issues surrounded by uncertainties or lack of data and information. No matter what efforts will be made to collect the available information and to assess the issues, nobody can clear all the uncertainties and make absolutely certain decision. More often than not, the regulators have to make a decision in light of continuing uncertainties and limited information. It is at this point that the principle of conservatism should play a role. However the principle comes in many diverse forms such as default conservatism, precautionary principle, defense in depth and realistic conservatism. These different forms of conservatism have different roles and meanings that will take a decision maker to drastically different results. This paper reviews different forms of conservatism in critical way, presents analytical framework for decision making under uncertainty and suggests future research works needed

The Department of Energy nuclear criticality safety program

International Nuclear Information System (INIS)

Felty, J.R.

2004-01-01

This paper broadly covers key events and activities from which the Department of Energy Nuclear Criticality Safety Program (NCSP) evolved. The NCSP maintains fundamental infrastructure that supports operational criticality safety programs. This infrastructure includes continued development and maintenance of key calculational tools, differential and integral data measurements, benchmark compilation, development of training resources, hands-on training, and web-based systems to enhance information preservation and dissemination. The NCSP was initiated in response to Defense Nuclear Facilities Safety Board Recommendation 97-2, Criticality Safety, and evolved from a predecessor program, the Nuclear Criticality Predictability Program, that was initiated in response to Defense Nuclear Facilities Safety Board Recommendation 93-2, The Need for Critical Experiment Capability. This paper also discusses the role Dr. Sol Pearlstein played in helping the Department of Energy lay the foundation for a robust and enduring criticality safety infrastructure.

Aviation safety : FAA and DOD response to similar safety concerns

Science.gov (United States)

2002-01-01

Report to the Honorable Norman Y. Mineta, Secretary of Transportation, and the Honorable Donald H. Rumsfeld, Secretary of Defense. : Safety of aircraft is a paramount concern in both civilian and military aviation. The Federal Aviation Administration...

High bit depth infrared image compression via low bit depth codecs

DEFF Research Database (Denmark)

Belyaev, Evgeny; Mantel, Claire; Forchhammer, Søren

2017-01-01

images via 8 bit depth codecs in the following way. First, an input 16 bit depth image is mapped into 8 bit depth images, e.g., the first image contains only the most significant bytes (MSB image) and the second one contains only the least significant bytes (LSB image). Then each image is compressed.......264/AVC codecs, which are usually available in efficient implementations, and compare their rate-distortion performance with JPEG2000, JPEG-XT and H.265/HEVC codecs supporting direct compression of infrared images in 16 bit depth format. A preliminary result shows that two 8 bit H.264/AVC codecs can...

Trapped between institutions and politics : The role of politics and social dynamics in institutional performance for flood defense management in Jakarta, Indonesia

NARCIS (Netherlands)

Simanjuntak, I.; Frantzeskaki, N.; Enserink, B.; Ravesteijn, W.

2011-01-01

Flood defense management in Jakarta is a critical governmental activity given that Jakarta is a low-lying delta metropolis and trade center which relies on its safety for the continuity of the economic activities. Despite the urgency for action flood defense policy implementation was a lengthy and

Nuclear health and safety

International Nuclear Information System (INIS)

1991-04-01

Numerous environmental, safety, and health problems found at other Department of Energy (DOE) defense nuclear facilities precipitated a review of these conditions at DOE's contractor-operated Pantex Plant, where our nation's nuclear weapons are assembled. This book focuses the review on examining key safety and health problems at Pantex and determining the need for external safety oversight of the plant

Successive Evolutions of the Defence in Depth Concept

Energy Technology Data Exchange (ETDEWEB)

Poulat, B., E-mail: B.Poulat@iaea.org [International Atomic Energy Agency (IAEA), Department of Nuclear Safety and Security, Wagramer Strasse 5, P.O. Box 100, 1400 Vienna (Austria)

2014-10-15

Following Fukushima Daiichi accident, the Defence-in-depth concept, which is usually defined as a combination of a number of consecutive and independent levels of protection that would have to fail before harmful effects could be caused, has been confirmed as an essential element to be applied in the design of a nuclear facility to protect people and the environment. However, and although the implementation of the defence in depth concept had been required for long, the Fukushima Daiichi accident and the “stress tests” conducted in different countries have revealed deficiencies in its implementation. Consequently within the review of the IAEA safety requirements requested by Member states, it was important to check whether this concept was appropriately defined in order to be properly understood and fully implemented by vendors and operating organizations. By screening the successive definitions of the defence in depth principle and concept, this paper emphasizes the few issues which have been gradually clarified and enhanced to ensure effectiveness of the defence in depth as expressed from its original statement. (author)

The safety of future reactors

International Nuclear Information System (INIS)

Tanguy, P.

1992-01-01

To sum up, I would like to underline once again the importance of experience feedback. This issue can only be properly handled by reversing the thought process which lay behind the construction of the current NPP's. The design was the springboard for building the reactors and then operating them. Throughout construction and at times during operation, many difficulties arose, which were overcome by modifications. The need today is to go back down the line in the opposite direction : to use operational and constructional experience to restructure the design. Furthermore, the design of future reactors appears to me as a process which must be founded upon two guiding principles : defense in depth and a PSA-type probabilistic approach. They seem to me ideally fitted to underpin such a process, especially in the case of an evolutionary-type reactor project. Such a strategy requires the cooperation of many participants supported by a high level of safety culture, as defined in the report published by the IAEA in 1991 : a permanent questioning attitude, a prudent approach and efficient communication between all of the individuals and organizations involved. Failure to make such an effort might well compromise the safety goals mentioned earlier in this paper. (author) any other organization. (author)

Western European Nuclear Regulators’ Association (WENRA) Views on Defence-in-Depth for New Reactors

Energy Technology Data Exchange (ETDEWEB)

Reiman, L.; Routamo, T. [STUK, Helsinki (Finland); Féron, F., E-mail: lasse.reiman@stuk.fi [ASN (France)

2014-10-15

WENRA published in 2010 a statement on safety objectives for new NPPs. Based on these objectives, WENRA decided to develop common positions, compiled in a booklet (available on www.wenra.org), on selected key safety issues for the design of new NPPs. One position presents WENRA’s Defence-in-Depth approach, describing WENRA’s expectation that multiple failure events and core melt accidents are considered in the original design of new nuclear power plants; another position presents expectations on the independence between different levels of Defence-in-Depth. (author)

Defence in Depth by Design for the Advanced GIII NPP in China

Energy Technology Data Exchange (ETDEWEB)

Liu, S.; Zhang, Y.; Zhang, X., E-mail: liusongtao.npic@gmail.com [Science and Technology on Reactor System Design Technology Laboratory Chengdu, Sichuan (China)

2014-10-15

This paper describes the design of the advanced nuclear power plant ACP1000 in China that keeps the principle of defence in depth. To enhance the safety of the new generation NPPs, passive and active engineering safety features are used. The reactor will be kept safe under design basis accidents by using active engineering safety features, such as the medium and low pressure safety injection systems, and the emergency feedwater system. Under beyond DBAs, the passive safety systems will be actuated to keep removing residual heat for more than 72 hours, and to keep the core melt retained and cooled in the vessel. After the Fukushima nuclear accident, there are six main design enhancements in ACP1000 to meet the demands of the China authorities. (author)

Proposal strategy and policy on nuclear safety for no-more severe accidents

International Nuclear Information System (INIS)

2013-01-01

Following the outspoken advice saying 'scientists and engineers concerning with nuclear power promotion and safety should be responsible for clarifying how preventable or what measures should be needed to prevent severe accidents occurring at Fukushima Daiichi nuclear power plants (NPPs)', committee on prevention of severe accidents at NPPs was established by relevant nuclear scientists and engineers involved so as to discuss basic issues to be solved from scientific and technical viewpoints. Based on the review of 'defense in depth' concept and accident analysis at Fukushima nuclear accident, four major proposals and six supplements to be established were identified such as: (1) finding mechanism of beyond imagination events for natural disaster, terrorism, and internal events, (2) reform of comprehensive safety standards and guidelines with performance basis easy to reflect latest knowledge and technology as 'back-fitting', (3) severe accidents measures, their validation, and drilling on accident management to advance procedures and develop human resources, and (4) risk communications and public disclosure of information. This article described backgrounds of committee's proposals on nuclear safety for no-more severe accidents. (T. Tanaka)

Groundwater Depth Affects Phosphorus But Not Carbon and Nitrogen Concentrations of a Desert Phreatophyte in Northwest China.

Science.gov (United States)

Zhang, Bo; Gao, Xiaopeng; Li, Lei; Lu, Yan; Shareef, Muhammad; Huang, Caibian; Liu, Guojun; Gui, Dongwei; Zeng, Fanjiang

2018-01-01

Ecological stoichiometry is an important aspect in the analysis of the changes in ecological system composition, structure, and function and understanding of plant adaptation in habitats. Leaf carbon (C), nitrogen (N), and phosphorus (P) concentrations in desert phreatophytes can be affected by different depths of groundwater through its effect on the adsorption and utilization of nutrient and plant biomass. We examined the biomass, soil organic C, available (mineral) N, and available P, and leaf C, N, and P concentrations of Alhagi sparsifolia grown at varying groundwater depths of 2.5, 4.5, and 11.0 m in 2015 and 2016 growing seasons in a desert-oasis ecotone in northwest China. The biomass of A. sparsifolia and the C, N, and P concentrations in soil and A. sparsifolia showed different responses to various groundwater depths. The leaf P concentration of A. sparsifolia was lower at 4.5 m than at 2.5 and 11.0 m likely because of a biomass dilution effect. By contrast, leaf C and N concentrations were generally unaffected by groundwater depth, thereby confirming that C and N accumulations in A. sparsifolia were predominantly determined by C fixation through the photosynthesis and biological fixation of atmospheric N 2 , respectively. Soil C, N, and P concentrations at 4.5 m were significantly lower than those at 11.0 m. Leaf P concentration was significantly and positively correlated with soil N concentration at all of the groundwater depths. The C:N and C:P mass ratios of A. sparsifolia at 4.5 m were higher than those at the other groundwater depths, suggesting a defensive life history strategy. Conversely, A. sparsifolia likely adopted a competitive strategy at 2.5 and 11.0 m as indicated by the low C:N and C:P mass ratios. To our knowledge, this study is the first to elucidate the variation in the C, N, and P stoichiometry of a desert phreatophyte at different groundwater depths in an arid ecosystem.

Bruce NGS a loss of flow analysis for effectiveness of level 2 defence-in-depth provisions

International Nuclear Information System (INIS)

Won, W.; Jiang, Y.; Kwee, M.; Xue, J.

2014-01-01

The concept of defence-in-depth is applied to CANDU (CANada Deuterium Uranium) reactor designs and operations to provide series of levels of defence to prevent accidents progressing and to provide protection for reactor and public safety. The level 2 defence-in-depth provisions are designed to detect and intercept deviation from normal operation in order to prevent anticipated operating occurrences (AOOs) from escalating to accident conditions, and to return the plant to a state of normal operations, according to the Canada Nuclear Safety Commission (CNSC) regulatory document RD-337. Historically, safety analysis has focused on the effectiveness of level 3 defence-in-depth provisions in accident conditions, and the effectiveness of level 2 defence-in-depth has not been assessed. In this study, the effectiveness of Level 2 defence-in-depth is assessed for loss of flow (LOF) events for Bruce Nuclear Generating Station (NGS) A reactors. The level 2 defence-in-depth in Bruce NGS A design is identified to be the stepback function of reactor regulating system (RRS). The behavior of RRS stepback following the initiation of loss of flow event is simulated using RFSP/TUF/RRS - em coupled code. The behavior of full system and single channel is simulated and assessed against the acceptance criteria - fitness for service of systems, structures and components (SSCs). (author)

Bruce NGS a loss of flow analysis for effectiveness of level 2 defence-in-depth provisions

Energy Technology Data Exchange (ETDEWEB)

Won, W. [AMEC NSS, Toronto, ON (Canada); Jiang, Y.; Kwee, M.; Xue, J. [Bruce Power, Toronto, ON (Canada)

2014-07-01

The concept of defence-in-depth is applied to CANDU (CANada Deuterium Uranium) reactor designs and operations to provide series of levels of defence to prevent accidents progressing and to provide protection for reactor and public safety. The level 2 defence-in-depth provisions are designed to detect and intercept deviation from normal operation in order to prevent anticipated operating occurrences (AOOs) from escalating to accident conditions, and to return the plant to a state of normal operations, according to the Canada Nuclear Safety Commission (CNSC) regulatory document RD-337. Historically, safety analysis has focused on the effectiveness of level 3 defence-in-depth provisions in accident conditions, and the effectiveness of level 2 defence-in-depth has not been assessed. In this study, the effectiveness of Level 2 defence-in-depth is assessed for loss of flow (LOF) events for Bruce Nuclear Generating Station (NGS) A reactors. The level 2 defence-in-depth in Bruce NGS A design is identified to be the stepback function of reactor regulating system (RRS). The behavior of RRS stepback following the initiation of loss of flow event is simulated using RFSP/TUF/RRS{sub -}em coupled code. The behavior of full system and single channel is simulated and assessed against the acceptance criteria - fitness for service of systems, structures and components (SSCs). (author)

Rock mechanics contributions from defense programs

International Nuclear Information System (INIS)

Heuze, F.E.

1992-02-01

An attempt is made at illustrating the many contributions to rock mechanics from US defense programs, over the past 30-plus years. Large advances have been achieved in the technology-base area covering instrumentation, material properties, physical modeling, constitutive relations and numerical simulations. In the applications field, much progress has been made in understanding and being able to predict rock mass behavior related to underground explosions, cratering, projectile penetration, and defense nuclear waste storage. All these activities stand on their own merit as benefits to national security. But their impact is even broader, because they have found widespread applications in the non-defense sector; to name a few: the prediction of the response of underground structures to major earthquakes, the physics of the earth's interior at great depths, instrumentation for monitoring mine blasting, thermo-mechanical instrumentation useful for civilian nuclear waste repositories, dynamic properties of earthquake faults, and transient large-strain numerical modeling of geological processes, such as diapirism. There is not pretense that this summary is exhaustive. It is meant to highlight success stories representative of DOE and DOD geotechnical activities, and to point to remaining challenges

Defence in depth for electric power supplies in Indian nuclear power plants

International Nuclear Information System (INIS)

Gupta, S.K.; Srivasista, K.; Solanki, R.B.

2009-01-01

The purpose of electric power supply system in a nuclear power plant is to supply and distribute reliable electric power to safety related systems and systems important to safety in various forms, arrangements and combinations of redundancy and diversity in order to perform safety functions required during operational states and design basis events (DBE) such as shutting down the reactor, maintaining the reactor in safe shutdown state, containment isolation and reactor core cooling preventing significant release of radioactive material to the environment. Hence the design basis of electric power supply systems includes identification of DBE that require power supplies, adequacy of redundancy and diversity, environmental conditions to which electric equipment are qualified, identification of loads requiring interrupted and uninterrupted power supplies, time sequence in which emergency loads are to be supplied in case of interruption, provisions for maintaining and testing, consideration for minimum duration capability of emergency power supplies during station blackout etc. Based on operation experience, results of probability safety assessment and certain weaknesses noticed in defence in depth of electric power supply systems, several continuous design improvements have been made in Indian nuclear power plants during operating phase and life extension. Instituting various tests during initial commissioning, subsequent operation and life extension has ensured high standards of performance of electric power supplies. Some of these aspects are highlighted in this paper

Safety at civil basic nuclear installations other than nuclear power plants in France. Lessons learned by IRSN from significant events reported in 2013 and 2014

International Nuclear Information System (INIS)

2016-01-01

IRSN publishes the lessons learned from its analysis of significant events which have occurred in 2013 and 2014 at 82 civil basic nuclear installations (INBs) other than nuclear power plants (NPPs). Produced every two year since 2009, this report concerns 73 facilities such as plants, laboratories, facilities for the treatment, disposal and storage of waste, and facilities which have been decommissioned, and 9 research reactors, operated by around twenty different licensees in France. 210 and 227 significant events were respectively reported in 2013 and 2014 to the French Nuclear Safety Authority (ASN). This number remains similar to previous years and tends to 'stabilize' at around 200 to 220. On the one hand, among the improvements observed in 2013 and 2014, IRSN found two subjects of particular interest: - Efforts made by the licensees to increase reliability of organisational and human measures related to handling operations, in particular at the spent fuel reprocessing plant of AREVA NC La Hague and in the radioactive waste storage facilities operated by the CEA. - Important improvement program deployed by the licensee of the FBFC plant in Romans-sur-Isere (Drome) to enhance operating practices, particularly regarding management of criticality risks (prevention of uncontrolled chain reactions). On the other hand, three subjects still require special vigilance by licensees: - Ensuring full control over the safety documentation of facilities. IRSN's cross-cutting analysis of events reveal a large number of cases for which parts of the safety documentation are not fully understood at the facilities, are not applied, are inaccurate or not applicable to the situation. - Ensuring in-depth and comprehensive planning of installation clean-up and dismantling operations. Risks of worker exposure to ionising radiation are higher during these operations which may require personnel to work in close proximity to radioactive materials. - Ensuring more

Defense Treaty Inspection Readiness Program

International Nuclear Information System (INIS)

Cronin, J.J.; Kohen, M.D.; Rivers, J.D.

1996-01-01

The Defense Treaty Inspection Readiness Program (DTIRP) was established by the Department of Defense in 1990 to assist defense facilities in preparing for treaty verification activities. Led by the On-Site Inspection Agency (OSIA), an element of the Department of Defense, DTIRP''s membership includes representatives from other Department of Defense agencies, the Department of Energy (DOE), the Central Intelligence Agency, the Federal Bureau of Investigation, the Department of Commerce, and others. The Office of Safeguards and Security has a significant interest in this program, due to the number of national defense facilities within its purview that are candidates for future inspections. As a result, the Office of Safeguards and Security has taken a very active role in DTIRP. This paper discusses the Office of Safeguards and Security''s increasing involvement in various elements of the DTIRP, ranging from facility assessments to training development and implementation

Opening Address [5. International Conference on Topical Issues in Nuclear Installation Safety: Defence in Depth — Advances and Challenges for Nuclear Installation Safety, Vienna, Austria, 21-24 October 2013

Energy Technology Data Exchange (ETDEWEB)

Flory, D. [International Atomic Energy Agency, Department of Nuclear Safety and Security, Vienna (Austria)

2014-10-15

We anticipate that the working sessions of this conference will allow us to share experience and enhance our understanding on safety measures on the implementation of DID in siting, design and construction; commissioning and operation; accident management and emergency preparedness and response; as well as the cross cutting organizational, technical and human factors issues that underlie defence in depth. While substantial efforts and resources have been invested to gain an understanding of what happened and why in the Fukushima Daiichi accident and much progress has been made, additional lessons learned will need to be taken forward. Learning and sharing lessons learned, and implementing the activities necessary for progress to be ongoing, is a quest for improvement that must never cease.

Tactile defensiveness and stereotyped behaviors.

Science.gov (United States)

Baranek, G T; Foster, L G; Berkson, G

1997-02-01

This study explores the constructs of stereotyped behaviors (e.g., repetitive motor patterns, object manipulations, behavioral rigidities) and tactile defensiveness as relevant to occupational therapy theory and practice and attempts to test their purported relationships in children with developmental disabilities. Twenty-eight children with developmental disabilities and autism were assessed on eight factors of stereotyped behavior via a questionnaire and by four measures of tactile defensiveness. The subjects' scores from the questionnaire were correlated with their scores on the tactile defensiveness measures to see what, if any, relationship among these behaviors exists. Significant relationships emerged from the data, indicating that subjects with higher levels of tactile defensiveness were also more likely to evidence rigid or inflexible behaviors, repetitive verbalizations, visual stereotypes, and abnormal focused affections that are often associated with autism. No significant association was found between motor and object stereotypes and tactile defensiveness. These relationships could not be explained solely by maturational factors. The results suggest that clinicians should include observations of stereotyped behaviors, particularly behavioral rigidities, in conjunction with assessments of sensory defensiveness because these are related phenomena that may pose unique challenges for children with developmental disabilities and autism. Further study is needed to determine the causal mechanisms responsible for these relationships.

The role of risk assessment and safety analysis in integrated safety assessments

International Nuclear Information System (INIS)

Niall, R.; Hunt, M.; Wierman, T.E.

1990-01-01

To ensure that the design and operation of both nuclear and non- nuclear hazardous facilities is acceptable, and meets all societal safety expectations, a rigorous deterministic and probabilistic assessment is necessary. An approach is introduced, founded on the concept of an ''Integrated Safety Assessment.'' It merges the commonly performed safety and risk analyses and uses them in concert to provide decision makers with the necessary depth of understanding to achieve ''adequacy.'' 3 refs., 1 fig

IRSN - Annual Report 2013. Financial Report 2013. Enhancing nuclear safety

International Nuclear Information System (INIS)

Schuler, Matthieu; Marchal, Valerie; Albert, Marc-Gerard; Aurelle, Jacques; Bigot, Marie-Pierre; Bruna, Giovanni; Charron, Sylvie; Clavelle, Stephanie; Cousinou, Patrick; Deschamps, Patrice; Delattre, Aleth; Demeillers, Didier; Dumas, Agnes; Franquard, Dominique; Laloi, Patrick; Lorthioir, Stephane; Monti, Pascale; Rollinger, Francois; Rouyer, Veronique; Rutschkovsky, Nathalie; Scott De Martinville, Edouard; Tharaud, Christine; Verpeaux, Jean-Luc; Jaunet, Camille; Hedouin, Jean-Christophe; Pascal-Heuze, Charlotte

2014-03-01

IRSN, a public entity with industrial and commercial activities, is placed under the joint authority of the Ministries of Defense, Environment, Industry, Research, and Health. It is the nation's public service expert in nuclear and radiation risks, and its activities cover all the related scientific and technical issues. Its areas of specialization include the environment and radiological emergency response, human radiation protection in both a medical and professional capacity, and in both normal and post-accident situations, the prevention of major accidents, nuclear reactor safety, as well as safety in nuclear plants and laboratories, transport and waste treatment, and nuclear defense and security expertise. IRSN interacts with all parties concerned by these risks (public authorities, in particular nuclear safety and security authorities, local authorities, companies, research organizations, stakeholders' associations, etc.) to contribute to public policy issues relating to nuclear safety, human and environmental protection against ionizing radiation, and the protection of nuclear materials, facilities, and transport against the risk of malicious acts. This document is the 2013 issue of IRSN's activity report. Content: 1 - Organization, key figures; 2 - Strategy: Progress and main activities in 2013, Transparency and communications policy, Promoting a safety and radiation protection culture; 3 - Activities: Safety (Safety of existing facilities, Studies and researches, About defense, Conducting assessments of future facilities); Nuclear security and non-proliferation (Nuclear security activities, International non-proliferation controls); Radiation protection - environment and human health (Environmental and population exposure, Radiation protection in the workplace, Effects of chronic exposure, Protection in health care); Emergency and post-accident situations efficiency; 4 - Efficiency: Health, safety, environmental, protection and quality, Human resources

Achieving RCRA compliance in DOE defense waste management operations

International Nuclear Information System (INIS)

Frankhauser, W.A.; Shepard, M.D.

1989-01-01

The U.S. Department of Energy (DOE) generates significant volumes of radioactive mixed waste (RMW) through its defense-related activities. Defense RMW is co-regulated by DOE and the U.S. Environmental Protection Agency/State agencies in accordance with requirements of the Resource Conservation and Recovery Act (RCRA) and the Atomic Energy Act (AEA). This paper highlights some of the problems encountered in co-regulation and discusses achievements of the defense waste management program in integrating RCRA requirements into RMW operations. Defense waste sites are planning facility modifications and major new construction projects to develop treatment, storage and disposal capacity for existing RMW inventories and projected needs

Emotional exhaustion and defense mechanisms in intensive therapy unit nurses.

Science.gov (United States)

Regan, Anna; Howard, Ruth A; Oyebode, Jan R

2009-05-01

Contrary to its original conceptualization, research has found that emotional demands do not lead to burnout in nurses. According to psychoanalytic theory, unconscious defense mechanisms may protect nurses from conscious awareness of work-related anxiety. This prevents self-report and may explain research findings. The maturity of defense style influences how anxiety is managed. Immature defenses prevent the conscious processing necessary for resolution of anxiety. Therefore, it is hypothesized that the use of immature defenses will lead to emotional exhaustion. This cross-sectional study used questionnaires to explore the defense mechanisms of 87 Intensive Therapy Unit nurses. Although the sample endorsed a predominantly mature defense style, the use of immature defenses predicted emotional exhaustion. Also, lower levels of reported stress associated with emotional demands predicted emotional exhaustion. Although this strongly implies the mediating role of immature defense mechanisms, the results were not statistically significant.

Effects of Gain/Loss Framing in Cyber Defense Decision-Making

Energy Technology Data Exchange (ETDEWEB)

Bos, Nathan; Paul, Celeste; Gersh, John; Greenberg, Ariel; Piatko, Christine; Sperling, Scott; Spitaletta, Jason; Arendt, Dustin L.; Burtner, Edwin R.

2016-10-24

Cyber defense requires decision making under uncertainty. Yet this critical area has not been a strong focus of research in judgment and decision-making. Future defense systems, which will rely on software-defined networks and may employ ‘moving target’ defenses, will increasingly automate lower level detection and analysis, but will still require humans in the loop for higher level judgment. We studied the decision making process and outcomes of 17 experienced network defense professionals who worked through a set of realistic network defense scenarios. We manipulated gain versus loss framing in a cyber defense scenario, and found significant effects in one of two focal problems. Defenders that began with a network already in quarantine (gain framing) used a quarantine system more than those that did not (loss framing). We also found some difference in perceived workload and efficacy. Alternate explanations of these findings and implications for network defense are discussed.

Human factors in layers of defense in airport security

NARCIS (Netherlands)

Andriessen, H.; Van Gulijk, C.; Ale, B.J.M.

2012-01-01

Airport security systems are built up out of layers of defence based on the security-in-depth model (Talbot & Jakeman, 2008). The Transport Safety Authority (TSA) in the United States defined a staggering 20 layers of defence to control security risks. This means that not only security personnel is

Enforcement actions: significant actions resolved. Quarterly progress report, January-June 1982

International Nuclear Information System (INIS)

1982-09-01

This compilation summarizes significant enforcement actions that have been resolved during two quarterly periods (January to June 1982) and includes copies of letters, notices, and orders sent by the Nuclear Regulatory Commission to the licensee with respect to the enforcement action. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, in the interest of promoting public health and safety as well as common defense and security. The intention is that this publication will be issued on a quarterly basis to include significant enforcement actions resolved during the preceding quarter

DHS Office of Health Affairs Chemical Defense Program Analyzes Subway Safety Against Chemical Terrorist Threats

OpenAIRE

Center for Homeland Defense and Security

2012-01-01

Center for Homeland Defense and Security, OUT OF THE CLASSROOM In an article for the journal Domestic Preparedness, Joselito Ignacio examines how to protect subway riders from chemical attacks. Ignacio graduated from the Center for Homeland Defense and Security in...

76 FR 72391 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

Science.gov (United States)

2011-11-23

... DEPARTMENT OF DEFENSE Office of the Secretary [Docket ID DOD-2011-OS-0055] Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense. ACTION: Revised Defense Logistics Agency...

Studies on the hepatic antioxidant defense system in &lambda ...

African Journals Online (AJOL)

Studies on the hepatic antioxidant defense system in λ cyhalothrin-induced ... Significant (P<0.05) elevation in the level of lipid peroxidation was observed in λ ... The results of the present investigation have indicated that the tissue antioxidant defense system is operating at a lower rate despite ... HOW TO USE AJOL.

Presentation on development of safety assessment reports in Romania

International Nuclear Information System (INIS)

Goicea, L.

2002-01-01

This presentation shows whole steps of Cernavoda 2 NPP licensing and accident management relevant changes considered. There are description of CANDU Safety principles and design criteria, as well as FSAR structured according to NRC Regulatory Guide 1.70, format of presentation of accident analyses, applicable acceptant criteria to analyses and Design Codes, Safety standards and Safety Guides used. The main features of CANDU reactors are presented, including of base design characteristics and describing of structures of CANDU reactors. During the licensing Cernavoda 2 are passed through Site approval, Construction permits of NPP system (1980-1993), Final construction license (1993) and Commissioning license (1995). In the May 1998 the First operating license is issued, based on FSAR Phase 1, Full power probationary report and carried out the requirements related to revising the FSAR and initiating of the Modernization program. To achieve the defense in depth concept are used and implemented the norms and quality standards during all plant stages, as well as selecting the high quality materials. During all plant stages is keeps strictly accomplishment of the quality requirements, and ensures a high level of reliability by using of operating principle and fabrication. In NPP operation is established using of the approved operating concept permitting only the safe condition for reactor operation. In the process of Cernavoda NPP licensing and operating the CSA and CGSB Canadian Standards, ASME and ANSI American Standards, Romanian Norms are implemented. Another useful Codes and Standards are implemented too, as ACI, ASTM, ANSI, AWS and others. In accident analysis for Safety Analysis Report for Cernavoda Unit 1 are involved 37 computer codes, in such areas as Reactor physics, Thermal-hydraulics, Fuel behavior, Fuel channel, Containment, and Fission product release and dose calculation

A new safety approach in the design of fast reactors

International Nuclear Information System (INIS)

Neuhold, R.J.; Marchaterre, J.F.; Waltar, A.E.

1987-01-01

A new approach to achieving fast reactor safety goals is becoming really apparent in the US Fast Reactor Program. Whereas the ''defense is best'' philosophy still prevails, there has been a tangible shift toward emphasizing passive mechanisms to protect the reactor and provide public safety---rather than relying on add-on active, engineered safety systems. This paper reviews the technical basis for this new safety approach and provides discussion on its implementation in current US liquid metal-cooled reactor designs. 4 refs., 4 figs

Safety principles for nuclear power plants

International Nuclear Information System (INIS)

Vuorinen, A.

1993-01-01

The role and purpose of safety principles for nuclear power plants are discussed. A brief information is presented on safety objectives as given in the INSAG documents. The possible linkage is discussed between the two mentioned elements of nuclear safety and safety culture. Safety culture is a rather new concept and there is more than one interpretation of the definition given by INSAG. The defence in depth is defined by INSAG as a fundamental principle of safety technology of nuclear power. Discussed is the overall strategy for safety measures, and features of nuclear power plants provided by the defence-in-depth concept. (Z.S.) 7 refs

Study of General health, resiliency, and defense mechanisms in patients with migraine headache

Directory of Open Access Journals (Sweden)

Alireza Aghayusefi

2013-06-01

Full Text Available Background: Migraine is a neurological disease that the etiology, several factors affect its onset or its exacerbation. One of the factors affecting disease is psychological factors such as defense mechanisms, resiliency, and general health. This study assessed the relationship between general health, resiliency, and general defense mechanisms, and also predicts the general health of people with migraine headaches that have a high resiliency and use mature defense mechanisms. Material and Methods: 50 women with migraine headache in the city of Bushehr using defense mechanisms, resiliency, and general health questionnaires were studied. For statistical analysis, Pearson correlation and multiple regression tests were used by SPSS 17 software. Results: The results showed that most of the defense mechanisms of migraine sufferers are Immature and Neuroticism. There is significant negative correlation between the deterioration of general health and resiliency as well as the mature defense mechanism (p=0/003, and also there is a significant positive correlation between this deterioration with neuroticism (p=0/040 and immature defense mechanisms (p=0/041. On the other hand there is significant negative correlation between resiliencies with immature (p=0/009 and neuroticism defense mechanisms (p=0/04, and also with mature defense mechanism has a significant positive correlation (p=0/003. Also, as more people use the mature defense mechanism, their deterioration of general health will be reduced, but this relationship will be stronger with the presence of resiliency. So migraine people use the mature defense mechanisms with high resiliency will have more favorable general health (less deterioration of general health. Conclusion: This study showed that migraine patients use the mature defense mechanisms with high resiliency will have more favorable general health (less deterioration of general health.

Promoter-Based Integration in Plant Defense Regulation

DEFF Research Database (Denmark)

Li, Baohua; Gaudinier, Allison; Tang, Michelle

2014-01-01

A key unanswered question in plant biology is how a plant regulates metabolism to maximize performance across an array of biotic and abiotic environmental stresses. In this study, we addressed the potential breadth of transcriptional regulation that can alter accumulation of the defensive...... glucosinolate metabolites in Arabidopsis (Arabidopsis thaliana). A systematic yeast one-hybrid study was used to identify hundreds of unique potential regulatory interactions with a nearly complete complement of 21 promoters for the aliphatic glucosinolate pathway. Conducting high-throughput phenotypic...... validation, we showed that >75% of tested transcription factor (TF) mutants significantly altered the accumulation of the defensive glucosinolates. These glucosinolate phenotypes were conditional upon the environment and tissue type, suggesting that these TFs may allow the plant to tune its defenses...

The Concept of Defense Management in the 21st Century within Indonesia Maritime Security Framework

Directory of Open Access Journals (Sweden)

Herlina Juni Risma Saragih

2018-03-01

Full Text Available Conflict of Maritime Security in the Asia Pacific region, especially South China Sea is a conflict that has long occurred and a problem that is often raised both in a regional and international level. Related to the conflict takes Strategy and Management of the State's defense to anticipate the impact of the conflict situations on defense and security of the region. The purpose of this study is to analyze the concept of Defence Management Indonesia in the 21st century in the context of Indonesian Maritime Security, Case Studies U.S Rebalancing in Asia Pacific and South China Sea conflict, as well as to determine the readiness of Defence Management capabilities in the face of threats. The method used is a qualitative method of data collection methods through in-depth interview to the informant. The results showed that in order to improve maritime security in Indonesia has not been implemented in a structured and comprehensive defense in accordance with the management perspective of the countries more advanced, especially on defense preparedness in logistics management as a managing and defense equipment avaible owned by Indonesia government. Based on these results it is suggested the need for socialization implementation of Defense Management in Asia Pacific by Indonesia government in the context of Maritime Security comprehensively.

Defence in Depth: Assessment of Comprehensiveness and Further Strengthening of the Concept

Energy Technology Data Exchange (ETDEWEB)

Misak, J., E-mail: Jozef.Misak@ujv.cz

2014-10-15

Full text: Defence in depth concept based on multiple levels of protection of the workers, public and the environment against radiation harm is and should remain an essential strategy for ensuring safety of nuclear power plants. This strategy should be comprehensively implemented through all stages of the plant lifetime, from the siting through construction and operation up to decommissioning. First part of the presentation will introduce a screening method developed by the IAEA as a tool facilitating the assessment of the comprehensiveness of defence in depth and will indicate further possibilities for using and updating the approach by taking into account recent lessons learned. Although it is clear that it is not possible for any industrial facility including nuclear power plants to fully eliminate the risk, further strengthening the defence in depth in particular at level 4 dealing with design extension conditions gives very high confidence in prevention and effective mitigation of severe accidents so that they are either practically eliminated or their consequences are limited in area and time. Second part of the presentation will discuss several issues associated with current efforts for strengthening the defence in depth, including the issues of practical elimination, independence and diversity of safety provisions at different levels of defence. (author)

Data-plane Defenses against Routing Attacks on Tor

Directory of Open Access Journals (Sweden)

Tan Henry

2016-10-01

Full Text Available Tor is susceptible to traffic correlation attacks in which an adversary who observes flows entering and leaving the anonymity network can apply statistical techniques to correlate flows and de-anonymize their endpoints. While an adversary may not be naturally positioned to conduct such attacks, a recent study shows that the Internet’s control-plane can be manipulated to increase an adversary’s view of the network, and consequently, improve its ability to perform traffic correlation. This paper explores, in-depth, the effects of control-plane attacks on the security of the Tor network. Using accurate models of the live Tor network, we quantify Tor’s susceptibility to these attacks by measuring the fraction of the Tor network that is vulnerable and the advantage to the adversary of performing the attacks. We further propose defense mechanisms that protect Tor users from manipulations at the control-plane. Perhaps surprisingly, we show that by leveraging existing trust anchors in Tor, defenses deployed only in the data-plane are sufficient to detect most control-plane attacks. Our defenses do not assume the active participation of Internet Service Providers, and require only very small changes to Tor. We show that our defenses result in a more than tenfold decrease in the effectiveness of certain control-plane attacks.

Management of safety culture

International Nuclear Information System (INIS)

Kavsek, D.

2004-01-01

The strengthening of safety culture in an organization has become an increasingly important issue for nuclear industry. A high level of safety performance is essential for business success in intensely competitive global environment. This presentation offers a discussion of some principles and activities used in enhancing safety performance and appropriate safety behaviour at the Krsko NPP. Over the years a number of events have occurred in nuclear industry that have involved problems in human performance. A review of these and other significant events has identified recurring weaknesses in plant safety culture and policy. Focusing attention on the strengthening of relevant processes can help plants avoid similar undesirable events. The policy of the Krsko NPP is that all employees concerned shall constantly be alert to opportunities to reduce risks to the lowest practicable level and to achieve excellence in plant safety. The most important objective is to protect individuals, society and the environment by establishing and maintaining an effective defense against radiological hazard in the nuclear power plant. It is achieved through the use of reliable structures, components, systems, and procedures, as well as plant personnel committed to a strong safety culture. The elements of safety culture include both organizational and individual aspects. Elements commonly included at the organizational level are senior management commitment to safety, organizational effectiveness, effective communication, organizational learning, and a culture that encourages identification and resolution of safety issues. Elements identified at the individual level include personal accountability, a questioning attitude, communication, procedural adherence, etc.(author)

Safety culture as an element of contact and cooperation between utilities, research and safety authorities

International Nuclear Information System (INIS)

Hoegberg, L.

1994-01-01

The safety culture approach may simply be seen as a recognition of the close interdependence between safety and organisational processes: achievement of technical safety objectives will largely depend on the quality of the implementation processes in the organisations concerned. With a slight modification of the original INSAG formulation, SKI defines safety culture as 'a consciously formulated and implemented set of values in an organisation, which establishes that, as an overriding priority, safety issues receive the attention warranted by their significance'. In practice, a high level of safety culture means the systematic organisation and implementation of a number of activities aimed at creating a high quality defence in depth against both technical and human failures that may cause accidents. An enquiring and learning attitude is a key element of such a safety culture. For example, to prevent accidents, the organisation always needs to be reactive to incidents, by performing proper root cause analysis of both technical and organisational factors, and taking appropriate corrective actions. The long term organisational objective should be to be proactive and identify deficiencies in technology and organisation that may lead to serious incidents or, at worst, accidents and take corrective action even before actual occurrence of incidents of substantial safety significance. (author) 13 refs

Depth of Cervical Intraepithelial Neoplasia Grade 3 in Peruvian Women: Implications for Therapeutic Depth of Necrosis.

Science.gov (United States)

Taxa, Luis; Jeronimo, Jose; Alonzo, Todd A; Gage, Julia; Castle, Philip E; Cremer, Miriam L; Felix, Juan C

2018-01-01

To determine the involvement of cervical intraepithelial neoplasia grade 3 (CIN3) in a population of women in a lower-resource setting. One hundred twelve consecutive cone excision specimens with histological diagnosis of CIN3 were retrieved from the National Institute of Neoplastic Diseases in Lima Peru. Two pathologists independently evaluated each specimen microscopically and confirmed 107 cases that could be measured by optical micrometry. Depth and breadth of the lesions were measured microscopically. The mean maximal depth of cervical involvement by CIN3 was 2 ± 0.13 mm; depth was less than 3.5 mm in 89.7% of cases and less than 5 mm in 93.5%. Mean breadth of CIN3 was 7.3 ± 4.4 mm; breadth was less than 15.9 mm in 95% of cases and less than 20.5 mm in 99.7%. The correlation coefficient between breadth and depth of CIN3 was 0.61. No significant correlation was found between age and depth. Depth of CIN3 involvement in a developing country is significantly deeper than that reported in the United States. Treatment selection for women with CIN3 and risk of treatment failure may vary between developing and developed countries because of the difference in the depth of lesions. Countries with underscreened populations need to consider the increased disease severity in devising treatment strategies.

Associations between parents' perception of neighbourhood environments and safety with physical activity of primary school children in Klang, Selangor, Malaysia.

Science.gov (United States)

Tung, S E H; Ng, X H; Chin, Y S; Mohd Taib, M N

2016-07-01

This study aimed to evaluate parental perception of neighbourhood environments and safety in association with children's physical activity among primary school children in Klang, Selangor, Malaysia. A total of 250 children (9-12 years of age) and their parents participated in this cross-sectional study. Physical Activity Questionnaire for Older Children and Neighbourhood Environmental Walkability Scale as well as questions on constrained behaviours (avoidance and defensive behaviours) were used to assess the children's physical activity and parental perception of neighbourhood environment and safety, respectively. More than one-third (36.0%) of the children were physically inactive compared with only a small percentage (4.8%) who were physically active, with boys achieving higher physical activity levels than girls (t = 2.564, P = 0.011). For the environmental scale, parents' perception of land-use mix (access) (r = 0.173, P = 0.006), traffic hazards (r = -0.152, P = 0.016) and defensive behaviour (r = -0.024, P = 0.143) correlated significantly with children's physical activity. In multiple linear regression analysis, child's gender (β = -0.226; P = 0.003), parent's education (β = 0.140; P = 0.001), household income (β = 0.151; P = 0.024), land-use mix (access) (β = 0.134; P = 0.011) and defensive behaviour (β = -0.017; P = 0.038) were significantly associated with physical activity in children (R = 0.349, F = 6.760; P safety and constrained behaviours with their children's participation in active play. Interventions aimed to increase actual and perceived safety and reduce perceptions of risk by parents in safe neighbourhoods can be targeted to increase children's physical activity in their local neighbourhoods. © 2016 John Wiley & Sons Ltd.

Safety at basic nuclear facilities other than nuclear power plants. Lessons learned from significant events reported in 2011 and 2012

International Nuclear Information System (INIS)

2014-01-01

The third report on the safety of basic nuclear installations in France other than power reactors presents an IRSN's analysis of significant events reported to the Nuclear Safety Authority in the years 2011 and 2012. It covers plants, laboratories, research reactors and facilities for the treatment, storage or disposal of waste. This report aims to contribute to a better understanding by stakeholders and more widely by the public of the safety and radiation protection issues associated with the operation of nuclear facilities, the progress made in terms of safety as well as the identified deficiencies. The main trend shows, once again, the significant role of organizational and human factors in the significant events that occurred in 2011 and 2012, of which the vast majority are without noteworthy consequences. Aging mechanisms are another major cause of equipment failure and require special attention. The report also provides IRSN's analysis of specific events that are particularly instructive for facility safety and a synthesis of assessments performed by IRSN on topics that are important for safety and radiation protection. IRSN also includes an overview of its analysis of measures proposed by licensees for increasing the safety of their facilities after the March 2011 accident at the Fukushima Daiichi nuclear power plant in Japan, which consist of providing a 'hardened safety core' to confront extreme situations (earthquake, flooding, etc.) that are unlikely but plausible and can bring about levels of hazards higher than those taken into account in the design of the facilities

The role of PSA in safety management

International Nuclear Information System (INIS)

Szikszai, T.

1997-01-01

The presentation discusses the following issues: defence in depth principle (the role of the barriers, how does PSA represents the barriers?); the safety management and nuclear power plants; the probabilistic and deterministic approaches; the PSA applications and safety management

Efficient Depth Enhancement Using a Combination of Color and Depth Information.

Science.gov (United States)

Lee, Kyungjae; Ban, Yuseok; Lee, Sangyoun

2017-07-01

Studies on depth images containing three-dimensional information have been performed for many practical applications. However, the depth images acquired from depth sensors have inherent problems, such as missing values and noisy boundaries. These problems significantly affect the performance of applications that use a depth image as their input. This paper describes a depth enhancement algorithm based on a combination of color and depth information. To fill depth holes and recover object shapes, asynchronous cellular automata with neighborhood distance maps are used. Image segmentation and a weighted linear combination of spatial filtering algorithms are applied to extract object regions and fill disocclusion in the object regions. Experimental results on both real-world and public datasets show that the proposed method enhances the quality of the depth image with low computational complexity, outperforming conventional methods on a number of metrics. Furthermore, to verify the performance of the proposed method, we present stereoscopic images generated by the enhanced depth image to illustrate the improvement in quality.

Light water reactor safety. Past, present and future

International Nuclear Information System (INIS)

Sehgal, Bal Raj

2009-01-01

This paper presents a review of the past, present and possible future developments in light water reactor (LWR) safety. The paper divides the past into two periods: the distant past i.e., before the TMI-2 accident when the main concern was with the design basis, the general design criteria, the concept of the defense in depth, the thermal hydraulics of the large loss of coolant accident (LOCA) and the success of the emergency core cooling system (ECCS), and the near past, i.e., after the TMI-2 accident when the main concern was with the physics of the postulated severe accidents: their prevention and mitigation. The present period is chosen as the translation of the research on the design basis and severe accidents into practical designs of Gen III+ with their core catchers and severe accident management (SAM) strategies, which could, in fact, provide ample assurances of public safety even for very severe accidents. The paper attempts to describe the remaining safety issues for both the Gen II and Gen III+ nuclear plants. The more important safety challenges are being posed by the recent moves of (1) extension of the life of the presently installed Gen II LWRs to 60 years (and perhaps to 80 years) and (2) the large uprates in power that are being sought for the Gen II LWRs. Clearly, the safety margins will be tested by these moves of long extended operations with greater power ratings of the Gen II plants. A prognosis of the emerging development trends in the LWR safety has been attempted with some suggestions. (author)

76 FR 28757 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

Science.gov (United States)

2011-05-18

... DEPARTMENT OF DEFENSE Office of the Secretary [DOCKET ID DOD-2011-OS-0055] Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense. ACTION: Notice of Availability (NOA) of Revised...

76 FR 53119 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

Science.gov (United States)

2011-08-25

... DEPARTMENT OF DEFENSE Office of the Secretary [Docket ID: DOD-2011-OS-0055] Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense. ACTION: Comment Addressed on Notice of...

Defense styles explain psychiatric symptoms: an empirical study.

Science.gov (United States)

Holi, M M; Sammallahti, P R; Aalberg, V A

1999-11-01

To examine the relation between psychiatric symptoms and defense mechanisms, we administered two questionnaires, the Symptom Check-list 90 (SCL-90) and the Defense Style Questionnaire (DSQ) to 122 psychiatric out-patients and to a community sample of 337 subjects. Using regression analysis, we found that 51.8% of the variation in subject's Global Severity Index value could be explained by his defense style. Of the three defense styles, the immature style explained most of the variation in the symptoms. We found little overall evidence for specific connections between particular defenses and symptoms. Projection and dissociation were central in most of the symptom dimensions. We compared patients and controls with the same level of general symptom severity and found that patients used significantly more devaluation and splitting, and controls used significantly more altruism and idealization. Whether defenses predispose to certain symptomatology or are one of its aspects is discussed.

LANL Safety Conscious Work Environment (SCWE) Self-Assessment

Energy Technology Data Exchange (ETDEWEB)

Hargis, Barbara C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-01-29

On December 21, 2012 Secretary of Energy Chu transmitted to the Defense Nuclear Facilities Safety Board (DNFSB) revised commitments on the implementation plan for Safety Culture at the Waste Treatment and Immobilization Plant. Action 2-5 was revised to require contractors and federal organizations to complete Safety Conscious Work Environment (SCWE) selfassessments and provide reports to the appropriate U.S. Department of Energy (DOE) - Headquarters Program Office by September 2013. Los Alamos National Laboratory (LANL) planned and conducted a Safety Conscious Work Environment (SCWE) Self-Assessment over the time period July through August, 2013 in accordance with the SCWE Self-Assessment Guidance provided by DOE. Significant field work was conducted over the 2-week period August 5-16, 2013. The purpose of the self-assessment was to evaluate whether programs and processes associated with a SCWE are in place and whether they are effective in supporting and promoting a SCWE.

Formal Specification and Run-time Monitoring Within the Ballistic Missile Defense Project

National Research Council Canada - National Science Library

Caffall, Dale S; Cook, Thomas; Drusinsky, Doron; Michael, James B; Shing, Man-Tak; Sklavounos, Nicholas

2005-01-01

.... Ballistic Missile Defense Advanced Battle Manager (ABM) project in an effort that is amongst the most comprehensive application of formal methods to a large-scale safety-critical software application ever reported...

Ego defense mechanisms in Pakistani medical students: a cross sectional analysis

Directory of Open Access Journals (Sweden)

Khalid Roha

2010-01-01

Full Text Available Abstract Background Ego defense mechanisms (or factors, defined by Freud as unconscious resources used by the ego to reduce conflict between the id and superego, are a reflection of how an individual deals with conflict and stress. This study assesses the prevalence of various ego defense mechanisms employed by medical students of Karachi, which is a group with higher stress levels than the general population. Methods A questionnaire based cross-sectional study was conducted on 682 students from five major medical colleges of Karachi over 4 weeks in November 2006. Ego defense mechanisms were assessed using the Defense Style Questionnaire (DSQ-40 individually and as grouped under Mature, Immature, and Neurotic factors. Results Lower mean scores of Immature defense mechanisms (4.78 were identified than those for Neurotic (5.62 and Mature (5.60 mechanisms among medical students of Karachi. Immature mechanisms were more commonly employed by males whereas females employed more Neurotic mechanisms than males. Neurotic and Immature defenses were significantly more prevalent in first and second year students. Mature mechanisms were significantly higher in students enrolled in Government colleges than Private institutions (p Conclusions Immature defense mechanisms were less commonly employed than Neurotic and Mature mechanisms among medical students of Karachi. The greater employment of Neurotic defenses may reflect greater stress levels than the general population. Employment of these mechanisms was associated with female gender, enrollment in a private medical college, and students enrolled in the first 2 years of medical school.

Seismic measures and defence in depth of nuclear power plant. Lessons learned from the great east Japan earthquake

International Nuclear Information System (INIS)

Ochiai, Kanehiro

2011-01-01

The Great East Japan Earthquake occurred in March 11, 2011 brought about severe accident at nuclear power plant, which gave significant lessons to nuclear experts concerned with safety measures. Concepts of defence in depth was basic philosophy to assure safety of nuclear power plant even against uncertainties exceeding design basis. This concept consisted of prevention, monitoring, and action to mitigate consequences of failures such as a series of physical barriers between the reactor core and the environment, which were called multiple safety systems, each with backup and designed to accommodate human error. As for natural disaster, depth of recognition of characteristic of natural phenomena and its effect and engineering judgment was of prime importance. Different waveforms of ground motion at Fukushima and Onagawa at the Great East Japan Earthquake showed that design ground motion should have large uncertainties. To cope with uncertainties of ground motion, robust seismic measures based on experience were such as design of static seismic intensity and rigid structure of natural period less than 0.1 sec. As for tsunami, defence in depth measures were prepared for the cooling of reactor core, spent fuel and related electric generation equipment with taking into account 1) time lag between tsunami generation and arrival, 2) tsunami affected area could be limited by coastal levee or anti-inundation measure, 3) system redundancy could be assured by different locations of equipments and 4) repair works could be done by shipment of replacement equipment from outside due to limitation of affected regional area. Success examples of Onagawa, Tokai unit 2, Fukushima Daiichi unit 6 and Fukushima Daini Nuclear Power Plants could suggest definite tsunami defence in depth measures. Containment vent system as final heat sink and emergency condenser as reactor core cooling at outage should be properly utilized for Fukushima Daiichi unit 1 Nuclear Power Plant. (T. Tanaka)

Defensive Medicine in U.S. Spine Neurosurgery.

Science.gov (United States)

Din, Ryan S; Yan, Sandra C; Cote, David J; Acosta, Michael A; Smith, Timothy R

2017-02-01

Observational cross-sectional survey. To compare defensive practices of U.S. spine and nonspine neurosurgeons in the context of state medical liability risk. Defensive medicine is a commonly reported and costly phenomenon in neurosurgery. Although state liability risk is thought to contribute greatly to defensive practice, variation within neurosurgical specialties has not been well explored. A validated, online survey was sent via email to 3344 members of the American Board of Neurological Surgeons. The instrument contained eight question domains: surgeon characteristics, patient characteristics, practice type, insurance type, surgeon liability profile, basic surgeon reimbursement, surgeon perceptions of medical legal environment, and the practice of defensive medicine. The overall response rate was 30.6% (n = 1026), including 499 neurosurgeons performing mainly spine procedures (48.6%). Spine neurosurgeons had a similar average practice duration as nonspine neurosurgeons (16.6 vs 16.9 years, P = 0.64) and comparable lifetime case volume (4767 vs 4,703, P = 0.71). The average annual malpractice premium for spine neurosurgeons was similar to nonspine neurosurgeons ($104,480.52 vs $101,721.76, P = 0.60). On average, spine neurosurgeons had a significantly higher rate of ordering labs, medications, referrals, procedures, and imaging solely for liability concerns compared with nonspine neurosurgeons (89.2% vs 84.6%, P = 0.031). Multivariate analysis revealed that spine neurosurgeons were roughly 3 times more likely to practice defensively compared with nonspine neurosurgeons (odds ratio, OR = 2.9, P = 0.001) when controlling for high-risk procedures (OR = 7.8, P < 0.001), annual malpractice premium (OR = 3.3, P = 0.01), percentage of patients publicly insured (OR = 1.1, P = 0.80), malpractice claims in the last 3 years (OR = 1.13, P = 0.71), and state medical-legal environment (OR = 1.3, P = 0

Application of System and Integration Readiness Levels to Department of Defense Research and Development

Science.gov (United States)

2016-07-01

prompting folding foot-pegs. The human-motorcycle interface maturity followed the technical maturity at the expense of safety. Early airplanes were...this paper shows matrix notation in both reduced tensor notation and matrix notation as a convenience for a multidisciplinary audience. SRLj, [SRL...index for managing the acquisition of defense systems. Paper presented at National Defense Industrial Association 13th Annual Systems Engineering

A method for risk-informed safety significance categorization using the analytic hierarchy process and bayesian belief networks

International Nuclear Information System (INIS)

Ha, Jun Su; Seong, Poong Hyun

2004-01-01

A risk-informed safety significance categorization (RISSC) is to categorize structures, systems, or components (SSCs) of a nuclear power plant (NPP) into two or more groups, according to their safety significance using both probabilistic and deterministic insights. In the conventional methods for the RISSC, the SSCs are quantitatively categorized according to their importance measures for the initial categorization. The final decisions (categorizations) of SSCs, however, are qualitatively made by an expert panel through discussions and adjustments of opinions by using the probabilistic insights compiled in the initial categorization process and combining the probabilistic insights with the deterministic insights. Therefore, owing to the qualitative and linear decision-making process, the conventional methods have the demerits as follows: (1) they are very costly in terms of time and labor, (2) it is not easy to reach the final decision, when the opinions of the experts are in conflict and (3) they have an overlapping process due to the linear paradigm (the categorization is performed twice - first, by the engineers who propose the method, and second, by the expert panel). In this work, a method for RISSC using the analytic hierarchy process (AHP) and bayesian belief networks (BBN) is proposed to overcome the demerits of the conventional methods and to effectively arrive at a final decision (or categorization). By using the AHP and BBN, the expert panel takes part in the early stage of the categorization (that is, the quantification process) and the safety significance based on both probabilistic and deterministic insights is quantified. According to that safety significance, SSCs are quantitatively categorized into three categories such as high safety significant category (Hi), potentially safety significant category (Po), or low safety significant category (Lo). The proposed method was applied to the components such as CC-V073, CV-V530, and SI-V644 in Ulchin Unit

Public safety risk management at socio-economic and / or historic-cultural significant dam sites

Energy Technology Data Exchange (ETDEWEB)

Earle, Gordon D.; Ryan, Katherine; Pyykonen, Nicole K.; Pitts, Lucas [Otonabee Region Conservation Authority, Peterborough, (Canada)

2010-07-01

The Lang Dam and adjoining gristmill, located near Peterborough are integral parts of the Lang Pioneer Village museum. Activities occurring within close proximity to the dam have led to safety issues. The owner (ORCA) has developed and implemented public safety management plans (PSMPs) for each of its water control structures, including the Lang Dam. ORCA gave special attention to the social, economic, aesthetic, historic and cultural dimensions associated the implementation of public safety management plans. These factors play a significant role in how well public safety measures (PSMs) are received by stakeholder groups and the general public. This paper reported the challenges of developing and implementing a PSMP for the Lang Dam, with the focus on property site-specific PSMS while preserving socio-economic and historic-cultural character and values. It was demonstrated that the dam owners, regulatory authorities, control agencies and preservationists need to come together to develop a holistic public safety management process.

Proposed Use of a Constructed Wetland for the Treatment of Metals in the S-04 Outfall of the Defense Waste Processing Facility at the Savannah River Site

International Nuclear Information System (INIS)

Glover, T.

1999-01-01

The DWPF is part of an integrated waste treatment system at the SRS to treat wastes containing radioactive contaminants. In the early 1980s the DOE recognized that there would be significant safety and cost advantages associated with immobilizing the radioactive waste in a stable solid form. The Defense Waste Processing Facility was designed and constructed to accomplish this task

Proposed Use of a Constructed Wetland for the Treatment of Metals in the S-04 Outfall of the Defense Waste Processing Facility at the Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

Glover, T.

1999-11-23

The DWPF is part of an integrated waste treatment system at the SRS to treat wastes containing radioactive contaminants. In the early 1980s the DOE recognized that there would be significant safety and cost advantages associated with immobilizing the radioactive waste in a stable solid form. The Defense Waste Processing Facility was designed and constructed to accomplish this task.

Establishment of a rationalized safety assurance logic aiming at FBRs with enhanced social acceptance (1). Interim report of CEA/JNC collaboration NWP-5(a) from 1999 to 2001: common view and JNC's contribution

International Nuclear Information System (INIS)

Niwa, Hajime; Tobita, Yoshiharu; Kurisaka, Kenichi; Kubo, Shigenobu; Kamiyama, Kenji

2001-12-01

This is an interim report describing the progress and the results of the collaborative research works between JNC and CEA on the safety logic in future fast reactors under the title of 'Establishment of a Rationalized Safety Assurance Logic Aiming at FBRs with Enhanced Social Acceptance' from 1999 to 2001. This contains JNC's contribution and common view of both partners. (1) Safety goals are proposed from JNC and CEA. Significant coherency is found such as to keep defense-in depth concept, mitigation measures against core melt are taken into account for containment design, evacuation free' concept is pursued, quantitative safety target is also considered as well as deterministic approach, and improvement of social acceptance is considered from the development stage of the fuel cycle including nuclear power plants. (2) Safety characteristics of each candidate coolant were compared and discussed. Gas-cooled fast reactor is a common interest area. Discussions are focused on: safety design requirements, safety evaluation events list, transient behavior analysis, core catcher designs, and so on. (3) JNC's results include criticality map for predicting CDA behavior and consequences, and CDA analysis results of lead-cooled and gas-cooled fast reactors with SIMMER-III. The collaboration on the action NWP-5a is recognized as being of great importance for the orientation of the innovative design studies. (author)

Effects of inserted depth of wall penetration on basal stability of foundation pits

Science.gov (United States)

Zhou, Aizhao; Shen, Hao; Sun, Jinguo

2017-05-01

Evaluation of basal heave stability is one of important design checks for excavations in soft clays. The commonly used classical calculation method based on limit equilibrium theory and the safety coefficient formula recommended by the current code, do not consider the influence of supporting structure of foundation pit depth heave stability, which results in conservative. Considering the wall stiffness and strength, the effective stress changes in different depth of soil, the frictional resistance between the retaining wall and the passive zone, the vertical shear resistance of the soil behind the wall and other factors. The modified safety factor calculation formula of foundation pit stability is presented, comparison analysis of calculation method combined with examples. The calculation results show that the safety factor of foundation pit stability is improved considering the influence of supporting structure depth, the calculation results are more reasonable.

Transportation System Risk Assessment on DOE Defense Program shipments

International Nuclear Information System (INIS)

Brumburgh, G.P.; Kimura, C.Y.; Alesso, H.P.; Prassinos, P.G.

1992-01-01

Substantial effort has been expended concerning the level of safety provided to persons, property, and the environment from the hazards associated with transporting radioactive material. This work provided an impetus for the Department of Energy to investigate the use of probabilistic risk assessment techniques to supplement the deterministic approach to transportation safety. The DOE recently decided to incorporate the methodologies associated with PRAs in the process for authorizing the transportation of nuclear components, special assemblies, and radioactive materials affiliated with the DOE Defense Program. Accordingly, the LLNL, sponsored by the DOE/AL, is tasked with developing a safety guide series to provide guidance to preparers performing a transportation system risk assessment

Basic recognition on safety of nuclear electric power generation

International Nuclear Information System (INIS)

Miyazaki, Keiji

1995-01-01

The safety of nuclear electric power generation is not to inflict radiation damage on public. Natural radiation is about 1 mSv every year. As far as the core melting on large scale does not occur, there is not the possibility of exerting serious radiation effect to public. The way of thinking on ensuring the safety is defense in depth. The first protection is the prevention of abnormality, the second protection is the prevention of accidents, and the third protection is the relaxation of effect. As design base accidents, the loss of coolant accident due to the breakdown of inlet pipings of reactors and the breaking of fine tubes in steam generators are included. The suitability of location is evaluated. As the large scale accidents of nuclear power stations in the past, Chernobyl accident and Three Mile Island accident are explained. The features of the countermeasures to the accident in Mihama No. 2 plant are described. The countermeasures to severe accidents, namely accident management and general preventive maintenance are explained. The background of the nonconfidence feeling to nuclear electric power generation and the importance of opening information to public are shown. (K.I.)

Should Nuclear Safety Care About Resilience Engineering?

International Nuclear Information System (INIS)

Paries, J.

2016-01-01

The current nuclear industry safety paradigm is based on the deterministic and/or probabilistic anticipation of all potential situations, and the predetermination of all the (safe) responses. Even the defense in depth concept, which is the core of the nuclear safety strategy and is intended to handle situations in which part of the control is lost, heavily relies on detailed anticipations. In other words, nuclear safety is mainly expected from the real world’s conformity to a designed-to-be-safe world, i.e., a well controlled world, where organizations, processes, hardware, teams, and individuals comply with their rationally predetermined behaviors. In this “command and control” perspective, risk is seen as mainly generated by deviations and variations from rules, procedures, norms, and expectations. However, real operations are complex, even in normal situations, which means that they include some unpredictable events and adaptation behaviors. The traditional “command and control” perspective fail to properly acknowledge the limits to predictability inherent to a complex adaptive system. It actually strives to reduce complexity through tighter compliance to specifications and to improve predictions capabilities through a tighter monitoring of “weak signals” and “precursors”. But in a complex world, precursors are usually obvious after the event, while not identifiable before. And the efforts made to reduce complexity may also simultaneously tighten couplings between system’s components— hence increase complexity — and reduce the diversity and flexibility needed to respond to it.

Defense Business Board

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Skip to main content (Press Enter). Toggle navigation Defense Business Board Search Search Defense Business Board: Search Search Defense Business Board: Search Defense Business Board Business Excellence in Defense of the Nation Defense Business Board Home Charter Members Meetings Studies Contact Us The Defense

Methodology for safety and security of radioactive sources and materials. The Israeli approach

International Nuclear Information System (INIS)

Keren, M.

1998-01-01

About 10 Radioactive incidents occurred in Israel during 1996-1997. Some of them were theft or lost of Radioactive equipment or sources, some happened because misuse of Radioactive equipment and some of other reasons. Part of them could be eliminated if a better methodological attitude to the subject existed. A new methodology for notification, registration and licensing is described. Hopefully this methodology will increase defense in depth and the Safety and Security of Radioactive sources and materials. Information on the inventory of Radioactive sources and materials is essential. Where they are situated, what is the supply rate or all history from berth to grave. Persons involved are important: Who are the Radiation Safety Officers (RSO), what is their training and updating programs. As much as possible information on the site and places where those Radioactive sources and materials are used. Procedures for security of sources and materials is part of site information, beside safety precautions. Users are obliged to inform on any changes and to ask for confirmation to those changes. The same is when high activity sources are moved across the country. (author)

Identifying the most significant indicators of the total road safety performance index.

Science.gov (United States)

Tešić, Milan; Hermans, Elke; Lipovac, Krsto; Pešić, Dalibor

2018-04-01

trauma management. This will help achieve the standardization of indicators including data collection procedures and selection of the key list of indicators that need to be monitored. Based on the results, it has been concluded that the use of the most contributing indicators will make it possible to assess the level of road safety on a territory, with an acceptable quality score by focusing on the low-ranked countries. A smaller set of significant indicators defined in this manner can serve for a fast and simple understanding of a road safety situation and assessment of effects of measures undertaken. Also, this universal index approach is applicable in cases when a broader comprehensive set of indicators is analyzed, which provides a more accurate identification of weaker points and rank the countries in a more meaningful way. Copyright © 2018 Elsevier Ltd. All rights reserved.

32 CFR 989.27 - Occupational safety and health.

Science.gov (United States)

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Occupational safety and health. 989.27 Section... PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.27 Occupational safety and health. Assess direct and indirect impacts of proposed actions on the safety and health of Air Force employees and...

SELF-DEFENSE IN KARABAKH CONFLICT?

Directory of Open Access Journals (Sweden)

Saeed Bagheri

2015-01-01

Full Text Available Use of force is one of the principles of international law which has been banned by the UN Charter and modern constitutions. However, since the enforcement of the UN Charter, self-defense has become the preferred excuse for states to justify their use of force. But applying self-defense requires some conditions. Immediacy is one of the important conditions of self-defense. Immediacy defined as the time span between armed attacks and reaction to it, is the main discourse. This condition requires self defense immediately after the armed conflict or during a rational time span since its occurance.In this respect, the emerging Karabakh Conflict between Armenia and Azerbaijan in the 1990s is important. After Armenia’s armed attacks, Azerbaijan has acted within the scope of legitimate self-defense. But in accordance with UN Security Council cease-fire resolution Azerbaijan has suspended its self-defense actions. However, today, still twenty percent of Azerbaijani territory is still under Armenian occupation. Accordingly, after a long time the validity of Azerbaijan’s right to legitimate self-defense is still subject to arguments.In this article, by comparing two different approaches (strict and board interpretation approaches on the temporal link between the measures of self-defense and the armed attacks (immediacy, the temporal link between the self-defense countermeasures of Azerbaijan and armed attacks by Armenia in Karabakh Conflict will be examined.

Analysis of collective defense in finals of 2012. Radivoj Korac Cup

Directory of Open Access Journals (Sweden)

Stanković Aleksandar

2013-01-01

Full Text Available The aim of this research was to determine and analyze use, the way of organization and successfulness of collective defense, as well as effects of use of specific defense types. In this case of study, empirically non experimental method and monitoring technique which enables research of technically tactical activities in basketball were used. The sample of research included eight basketball teams, competitors in finals of Radivoj Korac Cup, held in Nis in 2012. In the research seven games were analyzed - four quarterfinal games, two semifinal games and one finals game. The data was collected by the monitoring technique, and analysis of collective defense is done based on variables on which, organization and successfulness of collective defense depends on. Five general variables, seven that refers to the type of defense and five variables of defense activities were included in this analysis and the results of the survey were expressed with quantitative values. With data analysis, it was realized that the team that had higher percentage of general defense efficiency was winning the game. While watching the games an impression that, the players on outer positions were significantly contributing to the efficiency of defense was made, while inner positions players showed much less mobility in defense.

High bit depth infrared image compression via low bit depth codecs

Science.gov (United States)

Belyaev, Evgeny; Mantel, Claire; Forchhammer, Søren

2017-08-01

Future infrared remote sensing systems, such as monitoring of the Earth's environment by satellites, infrastructure inspection by unmanned airborne vehicles etc., will require 16 bit depth infrared images to be compressed and stored or transmitted for further analysis. Such systems are equipped with low power embedded platforms where image or video data is compressed by a hardware block called the video processing unit (VPU). However, in many cases using two 8-bit VPUs can provide advantages compared with using higher bit depth image compression directly. We propose to compress 16 bit depth images via 8 bit depth codecs in the following way. First, an input 16 bit depth image is mapped into 8 bit depth images, e.g., the first image contains only the most significant bytes (MSB image) and the second one contains only the least significant bytes (LSB image). Then each image is compressed by an image or video codec with 8 bits per pixel input format. We analyze how the compression parameters for both MSB and LSB images should be chosen to provide the maximum objective quality for a given compression ratio. Finally, we apply the proposed infrared image compression method utilizing JPEG and H.264/AVC codecs, which are usually available in efficient implementations, and compare their rate-distortion performance with JPEG2000, JPEG-XT and H.265/HEVC codecs supporting direct compression of infrared images in 16 bit depth format. A preliminary result shows that two 8 bit H.264/AVC codecs can achieve similar result as 16 bit HEVC codec.

Safety practice and regulations in different IGORR member countries

International Nuclear Information System (INIS)

Hickman, C.; Minguet, J.L.; Arnould, F.

1999-01-01

In the suggestions of the 1996 IGORR 5 conference, Technicatome proposed 'Comparing Regulations for Research Reactors in Participating Countries'. The aim was to enhance and facilitate the dissemination of pertinent information amongst potential utilities of operational research reactors. A questionnaire on the following topics was subsequently sent out to IGORR 5 participants : Procedures for Research Reactors and Associated Equipment, Safety Analysis, Safety Related Components, Radiation Protection and Management of Nuclear materials. The objective of the present paper is to identify major trends, similarities and differences in the approaches adopted by different countries. Its scope has been limited to: Licensing and Regulatory approach; Operating and Safety documents; Safety Analysis; Radiological Safety; Management of Nuclear Materials. The investigations carried out indicate that to a large extent international recommendations (IAEA, ICPR,..) are being followed and that there is a general tendency to integrate them into national legislation and regulations. Although Safety Culture varies from one country to another an overall general consensus exists on the basic approach to safety inasmuch as: different countries have their own legally defined Safety Authorities, a Preliminary Safety Report is required before a research reactor can be built, and a final Safety Report before the core can be loaded with nuclear fuel and the reactor made critical; these documents must be accepted by the Safety Authorities concerned; a combination of defense-in-depth strategy (deterministic approach) and probabilistic analysis is applied; three or more safety classes are used to categorize systems and components; the single failure criterion is taken into consideration for systems and components having safety functions; both Operating Basis and Safety Shutdown type earthquakes are considered; the crashing of an aircraft onto a research reactor is taken into consideration

A study of the face validity of the 40 item version of the Defense Style Questionnaire (DSQ-40).

Science.gov (United States)

Chabrol, Henri; Rousseau, Amélie; Rodgers, Rachel; Callahan, Stacey; Pirlot, Gérard; Sztulman, Henri

2005-11-01

There are few studies examining the face validity of the 40-item version of the Defense Style Questionnaire (DSQ-40). Moreover, the existing studies have provided conflicting results. The present study provides an in-depth examination of the face validity of the DSQ-40. Eight clinicians independently attributed each item of the DSQ-40 to a defense mechanism. The defense mechanisms listed in the DSM-IV Defensive Functioning Scale and their definitions were provided as a guide, along with the definition of those defense mechanisms investigated by the DSQ that are not included. It was further specified that the raters could attribute the items to defense mechanisms other than those listed or coping mechanisms. Twelve items out of 40 (30%) were attributed to the defense mechanisms they were supposed to investigate by fewer than four out of the eight raters. This result suggests that a substantial part of the DSQ-40 is lacking in face validity.

Enforcement actions: significant actions resolved. Quarterly progress report, July-September 1985. Volume 4, No. 3

International Nuclear Information System (INIS)

1985-11-01

This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July-September 1985) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions, and the licensees' responses. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, in the interest of promoting public health and safety as well as common defense and security

Enforcement actions: significant actions resolved. Quarterly progress report, January-March 1986. Volume 5, No. 1

International Nuclear Information System (INIS)

1986-05-01

This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (January-March 1986) and includes copies of letters, notices, and orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions, and the licensees' responses. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, in the interest of promoting public health and safety as well as common defense and security

Enforcement actions: significant actions resolved. Quarterly progress report, April-June 1986. Volume 5, No. 2

International Nuclear Information System (INIS)

1986-08-01

This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (April-June 1986) and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions and the licensees' responses. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, in the interest of promoting public health and safety as well as common defense and security

Enforcement actions: significant actions resolved. Quarterly progress report, July-September 1984. Volume 3, No. 3

International Nuclear Information System (INIS)

1984-10-01

This compilation summarizes significant enforcement actions that have been resolved during one quarterly period (July-September 1984 and includes copies of letters, Notices, and Orders sent by the Nuclear Regulatory Commission to licensees with respect to these enforcement actions and the licensees' responses. It is anticipated that the information in this publication will be widely disseminated to managers and employees engaged in activities licensed by the NRC, in the interest of promoting public health and safety as well as common defense and security

32 CFR 651.39 - Significance.

Science.gov (United States)

2010-07-01

... existing pollution standards; cause water, air, noise, soil, or underground pollution; impair visibility... Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.39 Significance. (a) If the...

Self-Defense in Karabakh Conflict?

Directory of Open Access Journals (Sweden)

Saeed Bagheri

2015-01-01

Full Text Available Use of force is one of the principles of international law that has been banned by the UN Charter and modern constitutions. However, since the enforcement of the UN Charter, self-defense has become the preferred excuse for states to justify their use of force. Applying self-defense, however, requires some conditions. Immediacy is one of the important conditions of self-defense. This is defined as the timeframe between armed attacks and reaction to it. This situation requires self-defense immediately after the armed conflict or during a reasonable timeframe since its occurance.In this respect, emerging Karabakh Conflict between Armenia and Azerbaijan in the 1990s is important. In this article, by comparing two different approaches (strict and board interpretation of the temporal link between the measures of self-defense and the armed attacks (immediacy, the temporal link between the self-defense countermeasures of Azerbaijan and attacks by Armenia in Karabakh Conflict will be examined.

Prevent recurrence of nuclear disaster (2). Reconstruction of safety logic diagram of nuclear system

International Nuclear Information System (INIS)

Miyano, Hiroshi; Sekimura, Naoto; Nakamura, Takao; Narumiya, Yoshiyuki

2012-01-01

On March 11, 2011, severe accident occurred at multi units of nuclear power caused by natural disaster, which was the first of nuclear power in the world, and lead to nuclear disaster which contaminated a wide range of land and caused surrounding residents to evacuate for a long-term. Since Cyuetsu-oki earthquake and before this accident, Atomic Energy Society of Japan had activities to investigate 'safety of nuclear system' against earthquake beyond any expectation, identify research items and work out roadmap on future research activities. Correspondence against tsunami such as this accident was discussed but not included as proposal because of low tsunami hazards awareness. Based on this reflection and to prevent recurrence of nuclear disaster, reconsideration of nuclear safety from the standpoint of defense-in-depth against hazards beyond any expectation had been performed and proposed to establish roadmap for its realization. Basic principle of nuclear safety consisted of eleven principles so as to protect personnel and environment from harmful effects of radiation derived from nuclear facilities and their activities, which were categorized into three groups (responsibility and management system, personnel and environmental protection and prevention of accident initiation and effect mitigation). (T. Tanaka)

From Comprehensive Defense to Resilient City: Strategic Conception of Shanghai’s City Security in the New Normal

Institute of Scientific and Technical Information of China (English)

Shi Tingting; Li Min

2017-01-01

The trend of climate warming and deeper globalization is adding new content to urban risks in Shanghai, resulting in the adaption of traditional comprehensive defense planning to the new environment. Based on the resilient city theory, this paper proposes a transition for Shanghai from an original comprehensive defense to a resilient city vision through strategic framework and approaches from the three aspects of engineering technology, spatial defense, and social governance in the New Normal age. Meanwhile, it suggests that Shanghai should use information technology to enhance the level of risk monitoring and to improve engineering design standards; strengthen the resilience from the scales of “life circle-urban circle-municipal administrative area”; and innovate as well as improve the social safety governance.

A generic standard for assessing and managing activities with significant risk to health and safety

International Nuclear Information System (INIS)

Wilde, T.S.; Sandquist, G.M.

2005-01-01

Some operations and activities in industry, business, and government can present an unacceptable risk to health and safety if not performed according to established safety practices and documented procedures. The nuclear industry has extensive experience and commitment to assessing and controlling such risks. This paper provides a generic standard based upon DOE Standard DOE-STD-3007- 93, Nov 1993, Change Notice No. 1, Sep 1998. This generic standard can be used to assess practices and procedures employed by any industrial and government entity to ensure that an acceptable level of safety and control prevail for such operations. When any activity and operation is determined to involve significant risk to health and safety to workers or the public, the organization should adopt and establish an appropriate standard and methodology to ensure that adequate health and safety prevail. This paper uses DOE experience and standards to address activities with recognized potential for impact upon health and safety. Existing and future assessments of health and safety issues can be compared and evaluated against this generic standard for insuring that proper planning, analysis, review, and approval have been made. (authors)

FY2017 Defense Spending Under an Interim Continuing Resolution (CR): In Brief

Science.gov (United States)

2016-11-07

generally applicable rate in Section 101: “Notwithstanding section 101, amounts are provided for ‘Defense Nuclear Facilities Safety Board— Salaries...acquisition community must consider late enactment to be the norm [emphasis in original] rather than the exception and, therefore, plan their...would be capped at 12, instead of the requested 15. If held to the lower FY2016 production rates through January 2017, the Air Force could face a

Economic approaches to measuring the significance of food safety in international trade.

Science.gov (United States)

Caswell, J A

2000-12-20

International trade in food products has expanded rapidly in recent years. This paper presents economic approaches for analyzing the effects on trade in food products of the food safety requirements of governments and private buyers. Important economic incentives for companies to provide improved food safety arise from (1) public incentives such as ex ante requirements for sale of a product with sufficient quality and ex post penalties (liability) for sale of products with deficient quality, and (2) private incentives for producing quality such as internal performance goals (self-regulation) and the external (certification) requirements of buyers. The World Trade Organization's Sanitary Phytosanitary Agreement facilitates scrutiny of the benefits and costs of country-level regulatory programs and encourages regulatory rapprochement on food safety issues. Economists can help guide risk management decisions by providing estimates of the benefits and costs of programs to improve food safety and by analyzing their effect on trade in food products.

Application of the AHP method to analyze the significance of the factors affecting road traffic safety

Directory of Open Access Journals (Sweden)

Justyna SORDYL

2015-06-01

Full Text Available Over the past twenty years, the number of vehicles registered in Poland has grown rapidly. At the same time, a relatively small increase in the length of the road network has been observed. As a result of the limited capacity of available infrastructure, it leads to significant congestion and to increase of the probability of road accidents. The overall level of road safety depends on many factors - the behavior of road users, infrastructure solutions and the development of automotive technology. Thus the detailed assessment of the importance of individual elements determining road safety is difficult. The starting point is to organize the factors by grouping them into categories which are components of the DVE system (driver - vehicle - environment. In this work, to analyze the importance of individual factors affecting road safety, the use of analytic hierarchy process method (AHP was proposed. It is one of the multi-criteria methods which allows us to perform hierarchical analysis of the decision process, by means of experts’ opinions. Usage of AHP method enabled us to evaluate and rank the factors affecting road safety. This work attempts to link the statistical data and surveys in significance analysis of the elements determining road safety.

Safety evaluation report of the Waste Isolation Pilot Plant safety analysis report: Contact-handled transuranic waste disposal operations

International Nuclear Information System (INIS)

1997-02-01

DOE 5480.23, Nuclear Safety Analysis Reports, requires that the US Department of Energy conduct an independent, defensible, review in order to approve a Safety Analysis Report (SAR). That review and the SAR approval basis is documented in this formal Safety Evaluation Report (SER). This SER documents the DOE's review of the Waste Isolation Pilot Plant SAR and provides the Carlsbad Area Office Manager, the WIPP SAR approval authority, with the basis for approving the safety document. It concludes that the safety basis documented in the WIPP SAR is comprehensive, correct, and commensurate with hazards associated with planned waste disposal operations

The impact of water depth on safety and environmental performance in offshore oil and gas production

International Nuclear Information System (INIS)

Muehlenbachs, Lucija; Cohen, Mark A.; Gerarden, Todd

2013-01-01

This paper reports on an empirical analysis of company-reported incidents on oil and gas production platforms in the Gulf of Mexico between 1996 and 2010. During these years, there was a dramatic increase in the water depths at which offshore oil and gas is extracted. Controlling for platform characteristics such as age, quantity of oil and gas produced, and number of producing wells, we find that incidents (such as blowouts, injuries, and oil spills) are positively correlated with deeper water. Controlling for these and other characteristics, for an average platform, each 100 feet of added depth increases the probability of a company-reported incident by 8.5%. While further research into the causal connections between water depth and platform risks is warranted, this study highlights the potential value of increased monitoring of deeper water platforms. - Highlights: ► Analysis of performance indicators for oil production platforms in Gulf of Mexico. ► In recent years there have been dramatic increases in the water depths at which offshore oil and gas is extracted. ► Self-reported incidents (e.g. blowouts, injuries, spills) increase with water depth

NEA’S Plans for Strengthening International Implementation of the Application of Defence in Depth Philosophies in Nuclear Power Countries

Energy Technology Data Exchange (ETDEWEB)

Blundell, N., E-mail: Neil.BLUNDELL@oecd.org [Nuclear Safety Division, OECD NEA, Paris (France)

2014-10-15

Full text: Following the Fukushima Daiichi Accident the OECD NEA established and delivered three tasks related to Defence in Depth for its member states. These consisted of: • A review of member state and NEA activities directly related to the accident by the Fukushima Senior Task Group set up by the OECD NEA Committee for Nuclear Regulatory Activities (CNRA). • An international expert review of the NEA’s wide ranging joint nuclear safety research portfolio. • A joint workshop on ‘Challenges and Enhancements to Defence in Depth (DiD) in light of the Fukushima Daiichi Accident’ on 5th June 2013 by both the OECD NEA Committee for Nuclear Regulatory Activities (CNRA) and Committee for the Safety of Nuclear Installations (CSNI). These tasks encompassed firstly, how the NEA member states understand the concept of DiD and its value within Nuclear Safety. Secondly, how DiD is implemented at present, focussing on how it is implemented to deal with external events, and finally what future areas the NEA members considered NEA as a whole should be carrying forward to enhance the understanding and implementation of Defence-in-Depth. Such areas included: • Exploring what the DiD safety goal concept ”practically eliminate large and early offsite releases” means and how is it implemented. • Independence and margins in the implementation of DiD. • Human interventions considering catastrophic external events effects on emergency response and recovery. • Detailed identification of additional safety research after Fukushima. This presentation provides a summary of those tasks and NEA’s international programme of activities to bring its members together in those areas they highlighted to deliver enhancement in the understanding and implementation of defence in depth. (author)

Significance of actinide chemistry for the long-term safety of waste disposal

International Nuclear Information System (INIS)

Kim, Jae Il

2006-01-01

A geochemical approach to the long-term safety of waste disposal is discussed in connection with the significance of actinides, which shall deliver the major radioactivity inventory subsequent to the relatively short-term decay of fission products. Every power reactor generates transuranic (TRU) elements: plutonium and minor actinides (Np, Am, Cm), which consist chiefly of long-lived nuclides emitting alpha radiation. The amount of TRU actinides generated in a fuel life period is found to be relatively small (about 1 wt% or less in spent fuel) but their radioactivity persists many hundred thousands years. Geological confinement of waste containing TRU actinides demands, as a result, fundamental knowledge on the geochemical behavior of actinides in the repository environment for a long period of time. Appraisal of the scientific progress in this subject area is the main objective of the present paper. Following the introductory discussion on natural radioactivities, the nuclear fuel cycle is briefly brought up with reference to actinide generation and waste disposal. As the long-term disposal safety concerns inevitably with actinides, the significance of the aquatic actinide chemistry is summarized in two parts: the fundamental properties relevant to their aquatic behavior and the geochemical reactions in nanoscopic scale. The constrained space of writing allows discussion on some examples only, for which topics of the primary concern are selected, e.g. apparent solubility and colloid generation, colloid-facilitated migration, notable speciation of such processes, etc. Discussion is summed up to end with how to make a geochemical approach available for the long-term disposal safety of nuclear waste or for the Performance Assessment (PA) as known generally

Department of Agriculture, Food Safety and Inspection Service

Science.gov (United States)

... Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices Careers Contact Us Ask ... Reports Fact Sheets Food Defense and Emergency Response Food Safety Education FSIS ... Assistance Contact Centers Cooperative Agreements Email Subscription ...

United States Coast Guard Antisubmarine Warfare (ASW) in the Maritime Defense Zone (MDZ) - A Strategic Approach

Science.gov (United States)

1989-03-01

RIC ILE COPY AIR WAR COLLGE REEAC R~pCR UNITED STATES COAST GUARD ANTISUBMARINE WARFARE (ASW) IN THE MARITIME DEFENSE ZONE (MDZ) -A STRATEGIC...going to perform in these MDZs. Those tasks identified so far include: port and coastal physical security & preventive safety, mine warfare

Safety culture - Is it important?

International Nuclear Information System (INIS)

Ayres, R.A.; Reiss, R.E.

1998-01-01

A strong and improving safety culture provides the foundation for building long term success for a company. It is a cultural change for most organizations and requires years not months to achieve. Short term successes are typically achieved and the smart companies build upon and communicate those successes. For long term success, these companies never deviate or become complacent about maintaining a strong safety culture. There are several lessons learned from the nuclear industry that support the need to maintain a strong safety culture: 1)prevention of human errors costs less than dealing with the consequences 2)poorly designed processes cause the majority of human errors 3)quality supervision is a powerful tool in human error reduction 4)performance monitoring/trending and technology based root cause analysis are essential to human error reduction 5)human errors caused by misjudgment need special attention 6)procedural non-compliance needs a focused solution based on organizational psychology 7)the benefits of a well designed accountability system are very significant 8)knowledge and skills, more rules, are the last line of defense against problems. (authors)

Is flood defense changing in nature? Shifts in the flood defense strategy in six European countries

Directory of Open Access Journals (Sweden)

Mathilde Gralepois

2016-12-01

Full Text Available In many countries, flood defense has historically formed the core of flood risk management but this strategy is now evolving with the changing approach to risk management. This paper focuses on the neglected analysis of institutional changes within the flood defense strategies formulated and implemented in six European countries (Belgium, England, France, the Netherlands, Poland, and Sweden. The evolutions within the defense strategy over the last 30 years have been analyzed with the help of three mainstream institutional theories: a policy dynamics-oriented framework, a structure-oriented institutional theory on path dependency, and a policy actors-oriented analysis called the advocacy coalitions framework. We characterize the stability and evolution of the trends that affect the defense strategy in the six countries through four dimensions of a policy arrangement approach: actors, rules, resources, and discourses. We ask whether the strategy itself is changing radically, i.e., toward a discontinuous situation, and whether the processes of change are more incremental or radical. Our findings indicate that in the European countries studied, the position of defense strategy is continuous, as the classical role of flood defense remains dominant. With changing approaches to risk, integrated risk management, climate change, urban growth, participation in governance, and socioeconomic challenges, the flood defense strategy is increasingly under pressure to change. However, these changes can be defined as part of an adaptation of the defense strategy rather than as a real change in the nature of flood risk management.

Review of the Safety Design Approaches in Sodium Fast Reactors

International Nuclear Information System (INIS)

Suk, Soo Dong; Lee, Yong Bum

2009-12-01

The principle of the Defense in depth is essential in securing the safety of nuclear power plants, that is, to prevent cores-damaging severs accidents and to minimize the radiological consequences of the accidents 'as low as possible' (ALARA). One of the major design features of sodium fast reactors (SFRs) is that it has a large amount of sodium in the reactor vessel, providing a large heat capacity, such that it is feasible to contain the consequences of sever core damaging accidents in the vessel and primary system boundary. Containment of a severe accident in the primary system boundary, that is called in-vessel retention(IVR), is not a licensing requirement but set up as a design goal in most of the SFR design in the context of risk minimization. The objective of this report is to broadly review and compare the approaches and efforts made in the some of the major SFR designs of the US, Europe and Japan to prevent severe accidents and mitigate their consequences should they occur. Specifically, the subjects described in this report include design criteria or requirements, accident categorization and acceptance criteria, design features to prevent and contain severs accidents

Fuel Receiving and Storage Station. Nuclear Regulatory Commission's safety evaluation report

International Nuclear Information System (INIS)

1976-01-01

The safety evaluation report covers design of structures, components, equipment, and systems; nuclear criticality safety; radiological safety; accident analysis; conduct of operations; quality assurance; common defense and security; financial qualifications; financial protection and indemnity requirements; and technical specifications

Changes in the glucosinolate-myrosinase defense system in Brassica juncea cotyledons during seedling development.

Science.gov (United States)

Wallace, S K; Eigenbrode, Sanford D

2002-02-01

Optimal defense theory (ODT) predicts that plant defenses will be allocated to plant organs and tissues in proportion to their relative fitness values and susceptibilities to attack. This study was designed to test ODT predictions on the myrosinase-glucosinolate defense system in Brassica juncea by examining the relationships between the fitness value of B. juncea cotyledons and the levels and effectiveness of cotyledon defenses. Specifically, we estimated fitness value of cotyledons during plant development by measuring plant growth and seed production after cotyledon damage or removal at successive seedling ages. Cotyledon removal within five days of emergence had a significant impact on growth and seed production, but cotyledon removal at later stages did not. Consistent with ODT, glucosinolate and myrosinase levels in cotyledons also declined with seedling age, as did relative defenses against a generalist herbivore, Spodoptera eridania, as estimated by bioassay. Declines in glucosinolates were as predicted by a passive, allometric dilution model based on cotyledon expansion. Declines in myrosinase activity were significantly more gradual than predicted by allometric dilution, suggesting active retention of myrosinase activity as young cotyledons expand.

Nuclear safety

International Nuclear Information System (INIS)

Tarride, Bruno

2015-10-01

The author proposes an overview of methods and concepts used in the nuclear industry, at the design level as well as at the exploitation level, to ensure an acceptable safety level, notably in the case of nuclear reactors. He first addresses the general objectives of nuclear safety and the notion of acceptable risk: definition and organisation of nuclear safety (relationships between safety authorities and operators), notion of acceptable risk, deterministic safety approach and main safety principles (safety functions and confinement barriers, concept of defence in depth). Then, the author addresses the safety approach at the design level: studies of operational situations, studies of internal and external aggressions, safety report, design principles for important-for-safety systems (failure criterion, redundancy, failure prevention, safety classification). The next part addresses safety during exploitation and general exploitation rules: definition of the operation domain and of its limits, periodic controls and tests, management in case of incidents, accidents or aggressions

32 CFR 234.17 - Vehicles and traffic safety.

Science.gov (United States)

2010-07-01

... 32 National Defense 2 2010-07-01 2010-07-01 false Vehicles and traffic safety. 234.17 Section 234...) MISCELLANEOUS CONDUCT ON THE PENTAGON RESERVATION § 234.17 Vehicles and traffic safety. (a) In general. Unless... an alcoholic beverage. (1) Each person within a vehicle is responsible for complying with the...

Measuring patient safety culture in maternal and child health institutions in China: a qualitative study.

Science.gov (United States)

Wang, Yuanyuan; Liu, Weiwei; Shi, Huifeng; Liu, Chaojie; Wang, Yan

2017-07-12

Patient safety culture (PSC) plays a critical role in ensuring safe and quality care. Extensive PSC studies have been undertaken in hospitals. However, little is known about PSC in maternal and child health (MCH) institutions in China, which provide both population-based preventive services as well as individual care for patients. This study aimed to develop a theoretical framework for conceptualising PSC in MCH institutions in China. The study was undertaken in six MCH institutions (three in Hebei and three in Beijing). Participants (n=118) were recruited through stratified purposive sampling: 20 managers/administrators, 59 care providers and 39 patients. In-depth interviews were conducted with the participants. The interview data were coded using both inductive (based on the existing PSC theory developed by the Agency for Healthcare Research and Quality) and deductive (open coding arising from data) approaches. A PSC framework was formulated through axial coding that connected initial codes and selective coding that extracted a small number of themes. The interviewees considered patient safety in relation to six aspects: safety and security in public spaces, safety of medical services, privacy and information security, financial security, psychological safety and gap in services. A 12-dimensional PSC framework was developed, containing 69 items. While the existing PSC theory was confirmed by this study, some new themes emerged from the data. Patients expressed particular concerns about psychological safety and financial security. Defensive medical practices emerged as a PSC dimension that is associated with not only medical safety but also financial security and psychological safety. Patient engagement was also valued by the interviewees, especially the patients, as part of PSC. Although there are some common features in PSC across different healthcare delivery systems, PSC can also be context specific. In MCH settings in China, the meaning of 'patient safety

"Hand down, man down." Analysis of defensive adjustments in response to the hot hand in basketball using novel defense metrics.

Science.gov (United States)

Csapo, Peter; Raab, Markus

2014-01-01

The hot-hand phenomenon, according to which a player's performance is significantly elevated during certain phases relative to the expected performance based on the player's base rate, has left many researchers and fans in basketball puzzled: The vast majority of players, coaches and fans believe in its existence but statistical evidence supporting this belief has been scarce. It has frequently been argued that the hot hand in basketball is unobservable because of strategic adjustments and defensive interference of the opposing team. We use a dataset with novel metrics, such as the number of defenders and the defensive intensity for each shot attempt, which enable us to directly measure defensive pressure. First, we examine how the shooting percentage of NBA players changes relative to the attributes of each metric. We find that it is of lesser importance by how many defenders a player is guarded but that defensive intensity, e.g., whether a defender raises his hand when his opponent shoots, has a larger impact on shot difficulty. Second, we explore how the underlying metrics and shooting accuracy change as a function of streak length. Our results indicate that defensive pressure and shot difficulty increase (decrease) during hot (cold) streaks, so that defenders seem to behave according to the hot-hand belief and try to force hot players into more difficult shots. However, we find that shooting percentages of presumably hot players do not increase and that shooting performance is not related to streakiness, so that the defenders' hot-hand behavior cannot be considered ecologically rational. Therefore, we are unable to find evidence in favor of the hot-hand effect even when accounting for defensive pressure.

"Hand down, man down." Analysis of defensive adjustments in response to the hot hand in basketball using novel defense metrics.

Directory of Open Access Journals (Sweden)

Peter Csapo

Full Text Available The hot-hand phenomenon, according to which a player's performance is significantly elevated during certain phases relative to the expected performance based on the player's base rate, has left many researchers and fans in basketball puzzled: The vast majority of players, coaches and fans believe in its existence but statistical evidence supporting this belief has been scarce. It has frequently been argued that the hot hand in basketball is unobservable because of strategic adjustments and defensive interference of the opposing team. We use a dataset with novel metrics, such as the number of defenders and the defensive intensity for each shot attempt, which enable us to directly measure defensive pressure. First, we examine how the shooting percentage of NBA players changes relative to the attributes of each metric. We find that it is of lesser importance by how many defenders a player is guarded but that defensive intensity, e.g., whether a defender raises his hand when his opponent shoots, has a larger impact on shot difficulty. Second, we explore how the underlying metrics and shooting accuracy change as a function of streak length. Our results indicate that defensive pressure and shot difficulty increase (decrease during hot (cold streaks, so that defenders seem to behave according to the hot-hand belief and try to force hot players into more difficult shots. However, we find that shooting percentages of presumably hot players do not increase and that shooting performance is not related to streakiness, so that the defenders' hot-hand behavior cannot be considered ecologically rational. Therefore, we are unable to find evidence in favor of the hot-hand effect even when accounting for defensive pressure.

Statistical Analysis and Evaluation of the Depth of the Ruts on Lithuanian State Significance Roads

Directory of Open Access Journals (Sweden)

Erinijus Getautis

2011-04-01

Full Text Available The aim of this work is to gather information about the national flexible pavement roads ruts depth, to determine its statistical dispersijon index and to determine their validity for needed requirements. Analysis of scientific works of ruts apearance in the asphalt and their influence for driving is presented in this work. Dynamical models of ruts in asphalt are presented in the work as well. Experimental outcome data of rut depth dispersijon in the national highway of Lithuania Vilnius – Kaunas is prepared. Conclusions are formulated and presented. Article in Lithuanian

[Study on psychiatric disorders and defensive process assessed by the "defense style questionnaire" in sterile males SAMPLE consulting in andrology].

Science.gov (United States)

Bellone, M; Cottencin, O; Rigot, J M; Goudemand, M

2005-01-01

The literature about artificial insemination and the associated psychological, psychiatric and sexual disorders is relatively rich. But the majority of these studies is made in gynaecology, with a feminine approach of the disorder. There are very few works led in andrology. This justified the investigation of new trails in order to understand better the clinical context of the sterile man. We undertake a study about the psychiatric disorders among sterile men and about the defense styles. These are a clinical entity recently introduced in the quantitative psychopathology research. The defense style questionnaire (DSQ) is a psychometric scale used in common practice in order to measure the defense styles. We made this study in order to examine the psychiatric state of a sterile males sample consulting in andrology; to assess the defense style by means of the Bond and al DSQ-88 ; to look into a difference between the defensive process according to their clinical situation of azoospermic males or as the oligoazoospermic males and finally, to reveal a correlation between the psychiatric disorders developed in this sample of sterile males and the defensive process they used. There were 42 people (22 azoospermic males and 20 oligoazoospermic males) aged between 23 and 49 years old in the analysed sample. These have been selected at the surgery of andrology at the RUHC of Lille, depending on their arrival order for 6 months. There was no significant difference between the two groups as far as the age and the education standard are concerned. The selection criteria were medical and somatic. Our sample population were divided into two groups: azoospermia (no spermatozoon found in the semen analysis) and oligoasthenospermia (decrease of the number and the mobility of the spermatozoa and an increase of the percentage of atypical forms). The method first consisted in the DSQ, followed by the analysis of the psychiatric state according to the DSM IV, a hetero questionnaire to

IAEA safety standards and approach to safety of advanced reactors

International Nuclear Information System (INIS)

Gasparini, M.

2004-01-01

The paper presents an overview of the IAEA safety standards including their overall structure and purpose. A detailed presentation is devoted to the general approach to safety that is embodied in the current safety requirements for the design of nuclear power plants. A safety approach is proposed for the future. This approach can be used as reference for a safe design, for safety assessment and for the preparation of the safety requirements. The method proposes an integration of deterministic and risk informed concepts in the general frame of a generalized concept of safety goals and defence in depth. This methodology may provide a useful tool for the preparation of safety requirements for the design and operation of any kind of reactor including small and medium sized reactors with innovative safety features.(author)

76 FR 42686 - DOE Response to Recommendation 2011-1 of the Defense Nuclear Facilities Safety Board, Safety...

Science.gov (United States)

2011-07-19

... examples of a failed safety culture.'' The Department disagrees with this categorization and believes the... Safety Board, Safety Culture at the Waste Treatment and Immobilization Plant AGENCY: Department of Energy... Recommendation 2011-1, concerning Safety Culture at the Waste Treatment and Immobilization Plant, to the...

Costs and trade-offs of grazer-induced defenses in Scenedesmus under deficient resource

Science.gov (United States)

Zhu, Xuexia; Wang, Jun; Chen, Qinwen; Chen, Ge; Huang, Yuan; Yang, Zhou

2016-01-01

The green alga Scenedesmus obliquus can form inducible defensive morphs under grazing threat. Costs and trade-offs of inducible defense are expected to accompany the benefits of defensive morphs, but are hard to detect under nutrient-sufficient experimental conditions. To test the existence of costs associated with inducible defense, we cultured S. obliquus along resource availability gradients in the presence or absence of infochemical cues from Daphnia, and measured the strength of defensive colony formation and fitness characters. Under the lowest phosphorous concentration, the expression of inducible defensive colony resulted in decreased growth rate, which provides direct evidence for physiological costs. Along the gradient reduction of phosphorous concentration or light intensity, inducible defense in S. obliquus showed a decreasing trend. However, the photosynthetic efficiency of S. obliquus was barely affected by its defense responses, suggesting that the negative correlations between resource availability and colony formation of this alga may be due to resource-based trade-offs in the allocation of limited resources. Thus, our results indicated that expression of inducible defense of S. obliquus was impaired under insufficient phosphorus or light. Furthermore, under severe phosphate deficiency, obvious physiological costs of inducible defense could be detected even though defensive colony formation also decreased significantly. PMID:26932369

Evaluation of Depth of Field for depth perception in DVR

KAUST Repository

Grosset, A.V.Pascal; Schott, Mathias; Bonneau, Georges-Pierre; Hansen, Charles D.

2013-01-01

In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

Evaluation of Depth of Field for depth perception in DVR

KAUST Repository

Grosset, A.V.Pascal

2013-02-01

In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

An approach toward estimating the safety significance of normal and abnormal operating procedures in nuclear power plants

International Nuclear Information System (INIS)

Grant, T.F.; Harris, M.S.

1989-01-01

The Nuclear Regulatory Commission's TMI Action Plan calls for a long-term plan to upgrade operating procedures in nuclear power plants. The scope of Generic Issue Human Factors 4.4, which stems from this requirement, includes the recommendation of improvements in nuclear power plant normal and abnormal operating procedures (NOPs and AOPs) and the implementation of appropriate regulatory action. This paper will describe the objectives, methodologies, and results of a Battelle-conducted value impact assessment to determine the costs and benefits of having the NRC implement regulatory action that would specify requirements for the preparation of acceptable NOPs and AOPs by the Commission's nuclear power plant licensees. The results of this value impact assessment are expressed in terms of ten cost/benefit attributes that can be affected by the NRC regulatory action. Five of these attributes require the calculation of change in public risk that could be expected to result from the action which, in this case, required determining the safety significance of NOPs and AOPs. In order to estimate this safety significance, a multi-step methodology was created that relies on an existing Probabilistic Risk Assessment (PRA) to provide a quantitative framework for modeling the role of operating procedures. The purpose of this methodology is to determine what impact the improvement of NOPs and AOPs would have on public health and safety

Improving the safety of future nuclear fission power plants

International Nuclear Information System (INIS)

Frisch, W.; Gros, G.

2001-01-01

The main objectives and principles in nuclear fission reactor safety are presented, e.g. the defence in depth strategy and technical principles such as redundancy, diversity and physical separation. After a brief historical review of the continuous development of safety improvement, the most recent international discussion is presented. This includes mainly the international activities within IAEA and its International Nuclear Safety Advisory Group (INSAG). The safety improvement, presented in recommendations of IAEA and INSAG is expressed as an improvement of all elements and all levels of the defence in depth concept. Special emphasis is put on improvement of the highest level, which requires the implementation of means to mitigate consequences of accidents with severe core damage. The different future concepts are briefly characterised. Some examples from the French-German safety approach are taken to demonstrate how requirements for safety improvement by means of an enhancement of the defence in depth principle are developed