Traceability of Software Safety Requirements in Legacy Safety Critical Systems
Hill, Janice L.
2007-01-01
How can traceability of software safety requirements be created for legacy safety critical systems? Requirements in safety standards are imposed most times during contract negotiations. On the other hand, there are instances where safety standards are levied on legacy safety critical systems, some of which may be considered for reuse for new applications. Safety standards often specify that software development documentation include process-oriented and technical safety requirements, and also require that system and software safety analyses are performed supporting technical safety requirements implementation. So what can be done if the requisite documents for establishing and maintaining safety requirements traceability are not available?
Analyzing Software Requirements Errors in Safety-Critical, Embedded Systems
Lutz, Robyn R.
1993-01-01
This paper analyzes the root causes of safety-related software errors in safety-critical, embedded systems. The results show that software errors identified as potentially hazardous to the system tend to be produced by different error mechanisms than non- safety-related software errors. Safety-related software errors are shown to arise most commonly from (1) discrepancies between the documented requirements specifications and the requirements needed for correct functioning of the system and (2) misunderstandings of the software's interface with the rest of the system. The paper uses these results to identify methods by which requirements errors can be prevented. The goal is to reduce safety-related software errors and to enhance the safety of complex, embedded systems.
International Nuclear Information System (INIS)
Sankar, Bindu; Sasidhar Rao, B.; Ilango Sambasivam, S.; Swaminathan, P.
2002-01-01
Full text: Real time computer systems are increasingly used for safety critical supervision and control of nuclear reactors. Typical application areas are supervision of reactor core against coolant flow blockage, supervision of clad hot spot, supervision of undesirable power excursion, power control and control logic for fuel handling systems. The most frequent cause of fault in safety critical real time computer system is traced to fuzziness in requirement specification. To ensure the specified safety, it is necessary to model the requirement specification of safety critical real time computer systems using formal mathematical methods. Modeling eliminates the fuzziness in the requirement specification and also helps to prepare the verification and validation schemes. Test data can be easily designed from the model of the requirement specification. Z and B are the popular languages used for modeling the requirement specification. A typical safety critical real time computer system for supervising the reactor core of prototype fast breeder reactor (PFBR) against flow blockage is taken as case study. Modeling techniques and the actual model are explained in detail. The advantages of modeling for ensuring the safety are summarized
Regulatory considerations for computational requirements for nuclear criticality safety
International Nuclear Information System (INIS)
Bidinger, G.H.
1995-01-01
As part of its safety mission, the U.S. Nuclear Regulatory Commission (NRC) approves the use of computational methods as part of the demonstration of nuclear criticality safety. While each NRC office has different criteria for accepting computational methods for nuclear criticality safety results, the Office of Nuclear Materials Safety and Safeguards (NMSS) approves the use of specific computational methods and methodologies for nuclear criticality safety analyses by specific companies (licensees or consultants). By contrast, the Office of Nuclear Reactor Regulation approves codes for general use. Historically, computational methods progressed from empirical methods to one-dimensional diffusion and discrete ordinates transport calculations and then to three-dimensional Monte Carlo transport calculations. With the advent of faster computational ability, three-dimensional diffusion and discrete ordinates transport calculations are gaining favor. With the proper user controls, NMSS has accepted any and all of these methods for demonstrations of nuclear criticality safety
2011 Annual Criticality Safety Program Performance Summary
Energy Technology Data Exchange (ETDEWEB)
Andrea Hoffman
2011-12-01
The 2011 review of the INL Criticality Safety Program has determined that the program is robust and effective. The review was prepared for, and fulfills Contract Data Requirements List (CDRL) item H.20, 'Annual Criticality Safety Program performance summary that includes the status of assessments, issues, corrective actions, infractions, requirements management, training, and programmatic support.' This performance summary addresses the status of these important elements of the INL Criticality Safety Program. Assessments - Assessments in 2011 were planned and scheduled. The scheduled assessments included a Criticality Safety Program Effectiveness Review, Criticality Control Area Inspections, a Protection of Controlled Unclassified Information Inspection, an Assessment of Criticality Safety SQA, and this management assessment of the Criticality Safety Program. All of the assessments were completed with the exception of the 'Effectiveness Review' for SSPSF, which was delayed due to emerging work. Although minor issues were identified in the assessments, no issues or combination of issues indicated that the INL Criticality Safety Program was ineffective. The identification of issues demonstrates the importance of an assessment program to the overall health and effectiveness of the INL Criticality Safety Program. Issues and Corrective Actions - There are relatively few criticality safety related issues in the Laboratory ICAMS system. Most were identified by Criticality Safety Program assessments. No issues indicate ineffectiveness in the INL Criticality Safety Program. All of the issues are being worked and there are no imminent criticality concerns. Infractions - There was one criticality safety related violation in 2011. On January 18, 2011, it was discovered that a fuel plate bundle in the Nuclear Materials Inspection and Storage (NMIS) facility exceeded the fissionable mass limit, resulting in a technical safety requirement (TSR) violation. The
Tank farms criticality safety manual
International Nuclear Information System (INIS)
FORT, L.A.
2003-01-01
This document defines the Tank Farms Contractor (TFC) criticality safety program, as required by Title 10 Code of Federal Regulations (CFR-), Subpart 830.204(b)(6), ''Documented Safety Analysis'' (10 CFR- 830.204 (b)(6)), and US Department of Energy (DOE) 0 420.1A, Facility Safety, Section 4.3, ''Criticality Safety.'' In addition, this document contains certain best management practices, adopted by TFC management based on successful Hanford Site facility practices. Requirements in this manual are based on the contractor requirements document (CRD) found in Attachment 2 of DOE 0 420.1A, Section 4.3, ''Nuclear Criticality Safety,'' and the cited revisions of applicable standards published jointly by the American National Standards Institute (ANSI) and the American Nuclear Society (ANS) as listed in Appendix A. As an informational device, requirements directly imposed by the CRD or ANSI/ANS Standards are shown in boldface. Requirements developed as best management practices through experience and maintained consistent with Hanford Site practice are shown in italics. Recommendations and explanatory material are provided in plain type
Linking Safety Analysis to Safety Requirements
DEFF Research Database (Denmark)
Hansen, Kirsten Mark
Software for safety critical systems must deal with the hazards identified by safety analysistechniques: Fault trees, event trees,and cause consequence diagrams can be interpreted as safety requirements and used in the design activity. We propose that the safety analysis and the system design use...
Requirement analysis of the safety-critical software implementation for the nuclear power plant
International Nuclear Information System (INIS)
Chang, Hoon Seon; Jung, Jae Cheon; Kim, Jae Hack; Nam, Sang Ku; Kim, Hang Bae
2005-01-01
The safety critical software shall be implemented under the strict regulation and standards along with hardware qualification. In general, the safety critical software has been implemented using functional block language (FBL) and structured language like C in the real project. Software design shall comply with such characteristics as; modularity, simplicity, minimizing the use of sub-routine, and excluding the interrupt logic. To meet these prerequisites, we used the computer-aided software engineering (CASE) tool to substantiate the requirements traceability matrix that were manually developed using Word processors or Spreadsheets. And the coding standard and manual have been developed to confirm the quality of software development process, such as; readability, consistency, and maintainability in compliance with NUREG/CR-6463. System level preliminary hazard analysis (PHA) is performed by analyzing preliminary safety analysis report (PSAR) and FMEA document. The modularity concept is effectively implemented for the overall module configurations and functions using RTP software development tool. The response time imposed on the basis of the deterministic structure of the safety-critical software was measured
Engineering design guidelines for nuclear criticality safety
International Nuclear Information System (INIS)
Waltz, W.R.
1988-08-01
This document provides general engineering design guidelines specific to nuclear criticality safety for a facility where the potential for a criticality accident exists. The guide is applicable to the design of new SRP/SRL facilities and to major modifications Of existing facilities. The document is intended an: A guide for persons actively engaged in the design process. A resource document for persons charged with design review for adequacy relative to criticality safety. A resource document for facility operating personnel. The guide defines six basic criticality safety design objectives and provides information to assist in accomplishing each objective. The guide in intended to supplement the design requirements relating to criticality safety contained in applicable Department of Energy (DOE) documents. The scope of the guide is limited to engineering design guidelines associated with criticality safety and does not include other areas of the design process, such as: criticality safety analytical methods and modeling, nor requirements for control of the design process
Software Safety Risk in Legacy Safety-Critical Computer Systems
Hill, Janice L.; Baggs, Rhoda
2007-01-01
Safety Standards contain technical and process-oriented safety requirements. Technical requirements are those such as "must work" and "must not work" functions in the system. Process-Oriented requirements are software engineering and safety management process requirements. Address the system perspective and some cover just software in the system > NASA-STD-8719.13B Software Safety Standard is the current standard of interest. NASA programs/projects will have their own set of safety requirements derived from the standard. Safety Cases: a) Documented demonstration that a system complies with the specified safety requirements. b) Evidence is gathered on the integrity of the system and put forward as an argued case. [Gardener (ed.)] c) Problems occur when trying to meet safety standards, and thus make retrospective safety cases, in legacy safety-critical computer systems.
Nuclear Criticality Safety Department Qualification Program
International Nuclear Information System (INIS)
Carroll, K.J.; Taylor, R.G.; Worley, C.A.
1996-01-01
The Nuclear Criticality Safety Department (NCSD) is committed to developing and maintaining a staff of highly qualified personnel to meet the current and anticipated needs in Nuclear Criticality Safety (NCS) at the Oak Ridge Y-12 Plant. This document defines the Qualification Program to address the NCSD technical and managerial qualification as required by the Y-1 2 Training Implementation Matrix (TIM). This Qualification Program is in compliance with DOE Order 5480.20A and applicable Lockheed Martin Energy Systems, Inc. (LMES) and Y-1 2 Plant procedures. It is implemented through a combination of WES plant-wide training courses and professional nuclear criticality safety training provided within the department. This document supersedes Y/DD-694, Revision 2, 2/27/96, Qualification Program, Nuclear Criticality Safety Department There are no backfit requirements associated with revisions to this document
ALARP considerations in criticality safety assessments
International Nuclear Information System (INIS)
Bowden, Russell L.; Barnes, Andrew; Thorne, Peter R.; Venner, Jack
2003-01-01
Demonstrating that the risk to the public and workers is As Low As Reasonably Practicable (ALARP) is a fundamental requirement of safety cases for nuclear facilities in the United Kingdom. This is embodied in the Safety Assessment Principles (SAPs) published by the Regulator, the essence of which is incorporated within the safety assessment processes of the various nuclear site licensees. The concept of ALARP within criticality safety assessments has taken some time to establish in the United Kingdom. In principle, the licensee is obliged to search for a deterministic criticality safety solution, such as safe geometry vessels and passive control features, rather than placing reliance on active measurement devices and plant administrative controls. This paper presents a consideration of some ALARP issues in relation to the development of criticality safety cases. The paper utilises some idealised examples covering a range of issues facing the criticality safety assessor, including new plant design, operational plant and decommissioning activities. These examples are used to outline the elements of the criticality safety cases and present a discussion of ALARP in the context of criticality safety assessments. (author)
Criticality Safety Evaluation for the TACS at DAF
Energy Technology Data Exchange (ETDEWEB)
Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2011-06-10
Hands-on experimental training in the physical behavior of multiplying systems is one of ten key areas of training required for practitioners to become qualified in the discipline of criticality safety as identified in DOE-STD-1135-99, Guidance for Nuclear Criticality Safety Engineer Training and Qualification. This document is a criticality safety evaluation of the training activities and operations associated with HS-3201-P, Nuclear Criticality 4-Day Training Course (Practical). This course was designed to also address the training needs of nuclear criticality safety professionals under the auspices of the NNSA Nuclear Criticality Safety Program1. The hands-on, or laboratory, portion of the course will utilize the Training Assembly for Criticality Safety (TACS) and will be conducted in the Device Assembly Facility (DAF) at the Nevada Nuclear Security Site (NNSS). The training activities will be conducted by Lawrence Livermore National Laboratory following the requirements of an Integrated Work Sheet (IWS) and associated Safety Plan. Students will be allowed to handle the fissile material under the supervision of an LLNL Certified Fissile Material Handler.
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
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.
DRY TRANSFER FACILITY CRITICALITY SAFETY CALCULATIONS
International Nuclear Information System (INIS)
C.E. Sanders
2005-01-01
This design calculation updates the previous criticality evaluation for the fuel handling, transfer, and staging operations to be performed in the Dry Transfer Facility (DTF) including the remediation area. The purpose of the calculation is to demonstrate that operations performed in the DTF and RF meet the nuclear criticality safety design criteria specified in the ''Project Design Criteria (PDC) Document'' (BSC 2004 [DIRS 171599], Section 4.9.2.2), the nuclear facility safety requirement in ''Project Requirements Document'' (Canori and Leitner 2003 [DIRS 166275], p. 4-206), the functional/operational nuclear safety requirement in the ''Project Functional and Operational Requirements'' document (Curry 2004 [DIRS 170557], p. 75), and the functional nuclear criticality safety requirements described in the ''Dry Transfer Facility Description Document'' (BSC 2005 [DIRS 173737], p. 3-8). A description of the changes is as follows: (1) Update the supporting calculations for the various Category 1 and 2 event sequences as identified in the ''Categorization of Event Sequences for License Application'' (BSC 2005 [DIRS 171429], Section 7). (2) Update the criticality safety calculations for the DTF staging racks and the remediation pool to reflect the current design. This design calculation focuses on commercial spent nuclear fuel (SNF) assemblies, i.e., pressurized water reactor (PWR) and boiling water reactor (BWR) SNF. U.S. Department of Energy (DOE) Environmental Management (EM) owned SNF is evaluated in depth in the ''Canister Handling Facility Criticality Safety Calculations'' (BSC 2005 [DIRS 173284]) and is also applicable to DTF operations. Further, the design and safety analyses of the naval SNF canisters are the responsibility of the U.S. Department of the Navy (Naval Nuclear Propulsion Program) and will not be included in this document. Also, note that the results for the Monitored Geologic Repository (MGR) Site specific Cask (MSC) calculations are limited to the
Nuclear criticality safety department training implementation
International Nuclear Information System (INIS)
Carroll, K.J.; Taylor, R.G.; Worley, C.A.
1996-01-01
The Nuclear Criticality Safety Department (NCSD) is committed to developing and maintaining a staff of qualified personnel to meet the current and anticipated needs in Nuclear Criticality Safety (NCS) at the Oak Ridge Y-12 Plant. The NCSD Qualification Program is described in Y/DD-694, Qualification Program, Nuclear Criticality Safety Department This document provides a listing of the roles and responsibilities of NCSD personnel with respect to training and details of the Training Management System (TMS) programs, Mentoring Checklists and Checksheets, as well as other documentation utilized to implement the program. This document supersedes Y/DD-696, Revision 2, dated 3/27/96, Training Implementation, Nuclear Criticality Safety Department. There are no backfit requirements associated with revisions to this document
USNRC licensing process as related to nuclear criticality safety
International Nuclear Information System (INIS)
Ketzlach, N.
1987-01-01
The U.S. Code of Federal Regulations establishes procedures and criteria for the issuance of licenses to receive title to, own, acquire, deliver, receive, possess, use, and initially transfer special nuclear material; and establishes and provides for the terms and conditions upon which the Nuclear Regulatory Commission (NRC) will issue such licenses. Section 70.22 of the regulations, ''Contents of Applications'', requires that applications for licenses contain proposed procedures to avoid accidental conditions of criticality. These procedures are elements of a nuclear criticality safety program for operations with fissionable materials at fuels and materials facilities (i.e., fuel cycle facilities other than nuclear reactors) in which there exists a potential for criticality accidents. To assist the applicant in providing specific information needed for a nuclear criticality safety program in a license application, the NRC has issued regulatory guides. The NRC requirements for nuclear criticality safety include organizational, administrative, and technical requirements. For purely technical matters on nuclear criticality safety these guides endorse national standards. Others provide guidance on the standard format and content of license applications, guidance on evaluating radiological consequences of criticality accidents, or guidance for dealing with other radiation safety issues. (author)
Safety of Research Reactors. Specific Safety Requirements (French Edition)
International Nuclear Information System (INIS)
2017-01-01
This Safety Requirements publication establishes requirements for all main areas of safety for research reactors, with particular emphasis on requirements for design and operation. It explains the safety objectives and concepts that form the basis for safety and safety assessment for all stages in the lifetime of a research reactor. Technical and administrative requirements for the safety of new research reactors are established in accordance with these objectives and concepts, and they are to be applied to the extent practicable for existing research reactors. The safety requirements established in this publication for the management of safety and regulatory supervision apply to site evaluation, design, manufacturing, construction, commissioning, operation (including utilization and modification), and planning for decommissioning of research reactors (including critical assemblies and subcritical assemblies). The publication is intended for use by regulatory bodies and other organizations with responsibilities in these areas and in safety analysis, verification and review, and the provision of technical support.
Test process for the safety-critical embedded software
International Nuclear Information System (INIS)
Sung, Ahyoung; Choi, Byoungju; Lee, Jangsoo
2004-01-01
Digitalization of nuclear Instrumentation and Control (I and C) system requires high reliability of not only hardware but also software. Verification and Validation (V and V) process is recommended for software reliability. But a more quantitative method is necessary such as software testing. Most of software in the nuclear I and C system is safety-critical embedded software. Safety-critical embedded software is specified, verified and developed according to V and V process. Hence two types of software testing techniques are necessary for the developed code. First, code-based software testing is required to examine the developed code. Second, after code-based software testing, software testing affected by hardware is required to reveal the interaction fault that may cause unexpected results. We call the testing of hardware's influence on software, an interaction testing. In case of safety-critical embedded software, it is also important to consider the interaction between hardware and software. Even if no faults are detected when testing either hardware or software alone, combining these components may lead to unexpected results due to the interaction. In this paper, we propose a software test process that embraces test levels, test techniques, required test tasks and documents for safety-critical embedded software. We apply the proposed test process to safety-critical embedded software as a case study, and show the effectiveness of it. (author)
Nuclear criticality safety training: guidelines for DOE contractors
International Nuclear Information System (INIS)
Crowell, M.R.
1983-09-01
The DOE Order 5480.1A, Chapter V, Safety of Nuclear Facilities, establishes safety procedures and requirements for DOE nuclear facilities. This guide has been developed as an aid to implementing the Chapter V requirements pertaining to nuclear criticality safety training. The guide outlines relevant conceptual knowledge and demonstrated good practices in job performance. It addresses training program operations requirements in the areas of employee evaluations, employee training records, training program evaluations, and training program records. It also suggests appropriate feedback mechanisms for criticality safety training program improvement. The emphasis is on academic rather than hands-on training. This allows a decoupling of these guidelines from specific facilities. It would be unrealistic to dictate a universal program of training because of the wide variation of operations, levels of experience, and work environments among DOE contractors and facilities. Hence, these guidelines do not address the actual implementation of a nuclear criticality safety training program, but rather they outline the general characteristics that should be included
International Nuclear Information System (INIS)
TOFFER, H.
2006-01-01
Since the end of the cold war, the need for operating weapons production facilities has faded. Criticality Safety Limits and controls supporting production modes in these facilities became outdated and furthermore lacked the procedure based rigor dictated by present day requirements. In the past, in many instances, the formalism of present day criticality safety evaluations was not applied. Some of the safety evaluations amounted to a paragraph in a notebook with no safety basis and questionable arguments with respect to double contingency criteria. When material stabilization, clean out, and deactivation activities commenced, large numbers of these older criticality safety evaluations were uncovered with limits and controls backed up by tenuous arguments. A dilemma developed: on the one hand, cleanup activities were placed on very aggressive schedules; on the other hand, a highly structured approach to limits development was required and applied to the cleanup operations. Some creative approaches were needed to cope with the limits development process
A study of software safety analysis system for safety-critical software
International Nuclear Information System (INIS)
Chang, H. S.; Shin, H. K.; Chang, Y. W.; Jung, J. C.; Kim, J. H.; Han, H. H.; Son, H. S.
2004-01-01
The core factors and requirements for the safety-critical software traced and the methodology adopted in each stage of software life cycle are presented. In concept phase, Failure Modes and Effects Analysis (FMEA) for the system has been performed. The feasibility evaluation of selected safety parameter was performed and Preliminary Hazards Analysis list was prepared using HAZOP(Hazard and Operability) technique. And the check list for management control has been produced via walk-through technique. Based on the evaluation of the check list, activities to be performed in requirement phase have been determined. In the design phase, hazard analysis has been performed to check the safety capability of the system with regard to safety software algorithm using Fault Tree Analysis (FTA). In the test phase, the test items based on FMEA have been checked for fitness guided by an accident scenario. The pressurizer low pressure trip algorithm has been selected to apply FTA method to software safety analysis as a sample. By applying CASE tool, the requirements traceability of safety critical system has been enhanced during all of software life cycle phases
Experience with performance based training of nuclear criticality safety engineers
International Nuclear Information System (INIS)
Taylor, R.G.
1993-01-01
For non-reactor nuclear facilities, the U.S. Department of Energy (DOE) does not require that nuclear criticality safety engineers demonstrate qualification for their job. It is likely, however, that more formalism will be required in the future. Current DOE requirements for those positions which do have to demonstrate qualification indicate that qualification should be achieved by using a systematic approach such as performance based training (PBT). Assuming that PBT would be an acceptable mechanism for nuclear criticality safety engineer training in a more formal environment, a site-specific analysis of the nuclear criticality safety engineer job was performed. Based on this analysis, classes are being developed and delivered to a target audience of newer nuclear criticality safety engineers. Because current interest is in developing training for selected aspects of the nuclear criticality safety engineer job, the analysis is incompletely developed in some areas
CANISTER HANDLING FACILITY CRITICALITY SAFETY CALCULATIONS
International Nuclear Information System (INIS)
C.E. Sanders
2005-01-01
This design calculation revises and updates the previous criticality evaluation for the canister handling, transfer and staging operations to be performed in the Canister Handling Facility (CHF) documented in BSC [Bechtel SAIC Company] 2004 [DIRS 167614]. The purpose of the calculation is to demonstrate that the handling operations of canisters performed in the CHF meet the nuclear criticality safety design criteria specified in the ''Project Design Criteria (PDC) Document'' (BSC 2004 [DIRS 171599], Section 4.9.2.2), the nuclear facility safety requirement in ''Project Requirements Document'' (Canori and Leitner 2003 [DIRS 166275], p. 4-206), the functional/operational nuclear safety requirement in the ''Project Functional and Operational Requirements'' document (Curry 2004 [DIRS 170557], p. 75), and the functional nuclear criticality safety requirements described in the ''Canister Handling Facility Description Document'' (BSC 2004 [DIRS 168992], Sections 3.1.1.3.4.13 and 3.2.3). Specific scope of work contained in this activity consists of updating the Category 1 and 2 event sequence evaluations as identified in the ''Categorization of Event Sequences for License Application'' (BSC 2004 [DIRS 167268], Section 7). The CHF is limited in throughput capacity to handling sealed U.S. Department of Energy (DOE) spent nuclear fuel (SNF) and high-level radioactive waste (HLW) canisters, defense high-level radioactive waste (DHLW), naval canisters, multicanister overpacks (MCOs), vertical dual-purpose canisters (DPCs), and multipurpose canisters (MPCs) (if and when they become available) (BSC 2004 [DIRS 168992], p. 1-1). It should be noted that the design and safety analyses of the naval canisters are the responsibility of the U.S. Department of the Navy (Naval Nuclear Propulsion Program) and will not be included in this document. In addition, this calculation is valid for the current design of the CHF and may not reflect the ongoing design evolution of the facility
Martin Marietta Energy Systems Nuclear Criticality Safety Improvement Program
International Nuclear Information System (INIS)
Speas, I.G.
1987-01-01
This report addresses questions raised by criticality safety violation at several DOE plants. Two charts are included that define the severity and reporting requirements for the six levels of accidents. A summary is given of all reported criticality incident at the DOE plants involved. The report concludes with Martin Marietta's Nuclear Criticality Safety Policy Statement
Overview of DOE/ONS criticality safety projects
International Nuclear Information System (INIS)
Barber, R.W.; Brown, B.P.; Hopper, C.M.
1985-01-01
The evolution of Federal involvement with nuclear criticality safety has traversed through the 1940's and early 1950's with the Manhattan Engineering District, the 1950's and 1960's with the Atomic Energy Commission, the early 1970's with the Energy Research and Development Administration, and the late 1970's to date with the US Department of Energy. The importance of nuclear criticality safety has been maintained throughout these periods; however, criticality safety has received shifting emphases in research/applications, promulgations of regulations/standards, origins of fiscal support and organization. In June 1981 the Office of Nuclear Safety was established in response to a Department of Energy study of the impact of the March 1979 Three Mile Island accident. The organizational structure of the ONS, its program for establishing and maintaining a progressive nuclear criticality safety program, and associated projects, and current history of ONS's fiscal support of program projects is presented. With the establishment of the ONS came concomitant missions to develop and maintain nuclear safety policy and requirements, to provide independent assurance that nuclear operations are performed safely, to provide resources and management for DOE responses to nuclear accidents, and to provide technical support. In the past four years, ONS has developed and initiated a continuing Department Nuclear Criticality Safety Program in such areas as communications and information, physics of criticality, knowledge of factors affecting criticality, and computational capability
Supplement to safety analysis report. 306-W building operations safety requirement
International Nuclear Information System (INIS)
Richey, C.R.
1979-08-01
The operations safety requirements (OSRs) presented in this report define the conditions, safe boundaries, and management control needed for safely conducting operations with radioactive materials in the Pacific Northwest Laboratory (PNL) 306-W building. The safety requirements are organized in five sections. Safety limits are safety-related process variables that are observable and measurable. Limiting conditions cover: equipment and technical conditions and characteristics of the facility and operations necessary for continued safe operation. Surveillance requirements prescribe the requirements for checking systems and components that are essential to safety. Equipment design controls require that changes to process equipment and systems be independently checked and approved to assure that the changes will have no adverse effect on safety. Administrative controls describe and discuss the organization and administrative systems and procedures to be used for safe operation of the facility. Details of the implementation of the operations safety requirements are prescribed by internal PNL documents such as criticality safety specifications and radiation work procedures
International Nuclear Information System (INIS)
Walker, G.
1983-01-01
When a sufficient quantity of fissile material is brought together a self-sustaining neutron chain reaction will be started in it and will continue until some change occurs in the fissile material to stop the chain reaction. The quantity of fissile material required is the 'Critical Mass'. This is not a fixed quantity even for a given type of fissile material but varies between quite wide limits depending on a number of factors. In a nuclear reactor the critical mass of fissile material is assembled under well-defined condition to produce a controllable chain reaction. The same materials have to be handled outside the reactor in all stages of fuel element manufacture, storage, transport and irradiated fuel reprocessing. At any stage it is possible (at least in principle) to assemble a critical mass and thus initiate an accidental and uncontrollable chain reaction. Avoiding this is what criticality safety is all about. A system is just critical when the rate of production of neutrons balances the rate of loss either by escape or by absorption. The factors affecting criticality are, therefore, those which effect neutron production and loss. The principal ones are:- type of nuclide and enrichment (or isotopic composition), moderation, reflection, concentration (density), shape and interaction. Each factor is considered in detail. (author)
Tank waste remediation system nuclear criticality safety inspection and assessment plan
International Nuclear Information System (INIS)
VAIL, T.S.
1999-01-01
This plan provides a management approved procedure for inspections and assessments of sufficient depth to validate that the Tank Waste Remediation System (TWRS) facility complies with the requirements of the Project Hanford criticality safety program, NHF-PRO-334, ''Criticality Safety General, Requirements''
Experience with performance based training of nuclear criticality safety engineers
International Nuclear Information System (INIS)
Taylor, R.G.
1993-01-01
Historically, new entrants to the practice of nuclear criticality safety have learned their job primarily by on-the-job training (OJT) often by association with an experienced nuclear criticality safety engineer who probably also learned their job by OJT. Typically, the new entrant learned what he/she needed to know to solve a particular problem and accumulated experience as more problems were solved. It is likely that more formalism will be required in the future. Current US Department of Energy requirements for those positions which have to demonstrate qualification indicate that it should be achieved by using a systematic approach such as performance based training (PBT). Assuming that PBT would be an acceptable mechanism for nuclear criticality safety engineer training in a more formal environment, a site-specific analysis of the nuclear criticality safety engineer job was performed. Based on this analysis, classes are being developed and delivered to a target audience of newer nuclear criticality safety engineers. Because current interest is in developing training for selected aspects of the nuclear criticality safety engineer job, the analysis i's incompletely developed in some areas. Details of this analysis are provided in this report
CANISTER HANDLING FACILITY CRITICALITY SAFETY CALCULATIONS
Energy Technology Data Exchange (ETDEWEB)
C.E. Sanders
2005-04-07
This design calculation revises and updates the previous criticality evaluation for the canister handling, transfer and staging operations to be performed in the Canister Handling Facility (CHF) documented in BSC [Bechtel SAIC Company] 2004 [DIRS 167614]. The purpose of the calculation is to demonstrate that the handling operations of canisters performed in the CHF meet the nuclear criticality safety design criteria specified in the ''Project Design Criteria (PDC) Document'' (BSC 2004 [DIRS 171599], Section 4.9.2.2), the nuclear facility safety requirement in ''Project Requirements Document'' (Canori and Leitner 2003 [DIRS 166275], p. 4-206), the functional/operational nuclear safety requirement in the ''Project Functional and Operational Requirements'' document (Curry 2004 [DIRS 170557], p. 75), and the functional nuclear criticality safety requirements described in the ''Canister Handling Facility Description Document'' (BSC 2004 [DIRS 168992], Sections 3.1.1.3.4.13 and 3.2.3). Specific scope of work contained in this activity consists of updating the Category 1 and 2 event sequence evaluations as identified in the ''Categorization of Event Sequences for License Application'' (BSC 2004 [DIRS 167268], Section 7). The CHF is limited in throughput capacity to handling sealed U.S. Department of Energy (DOE) spent nuclear fuel (SNF) and high-level radioactive waste (HLW) canisters, defense high-level radioactive waste (DHLW), naval canisters, multicanister overpacks (MCOs), vertical dual-purpose canisters (DPCs), and multipurpose canisters (MPCs) (if and when they become available) (BSC 2004 [DIRS 168992], p. 1-1). It should be noted that the design and safety analyses of the naval canisters are the responsibility of the U.S. Department of the Navy (Naval Nuclear Propulsion Program) and will not be included in this document. In addition, this calculation is valid for
ACRR fuel storage racks criticality safety analysis
International Nuclear Information System (INIS)
Bodette, D.E.; Naegeli, R.E.
1997-10-01
This document presents the criticality safety analysis for a new fuel storage rack to support modification of the Annular Core Research Reactor for production of molybdenum-99 at Sandia National Laboratories, Technical Area V facilities. Criticality calculations with the MCNP code investigated various contingencies for the criticality control parameters. Important contingencies included mix of fuel element types stored, water density due to air bubbles or water level for the over-moderated racks, interaction with existing fuel storage racks and fuel storage holsters in the fuel storage pool, neutron absorption of planned rack design and materials, and criticality changes due to manufacturing tolerances or damage. Some limitations or restrictions on use of the new fuel storage rack for storage operations were developed through the criticality analysis and are required to meet the double contingency requirements of criticality safety. As shown in the analysis, this system will remain subcritical under all credible upset conditions. Administrative controls are necessary for loading, moving, and handling the storage rack as well as for control of operations around it. 21 refs., 16 figs., 4 tabs
Nuclear criticality safety parameter evaluation for uranium metallic alloy
Energy Technology Data Exchange (ETDEWEB)
Sanchez, Andrea; Abe, Alfredo, E-mail: andreasdpz@hotmail.com, E-mail: abye@uol.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Energia Nuclear
2013-07-01
Nuclear criticality safety during fuel fabrication process, transport and storage of fissile and fissionable materials requires criticality safety analysis. Normally the analysis involves computer calculations and safety parameters determination. There are many different Criticality Safety Handbooks where such safety parameters for several different fissile mixtures are presented. The handbooks have been published to provide data and safety principles for the design, safety evaluation and licensing of operations, transport and storage of fissile and fissionable materials. The data often comprise not only critical values, but also subcritical limits and safe parameters obtained for specific conditions using criticality safety calculation codes such as SCALE system. Although many data are available for different fissile and fissionable materials, compounds, mixtures, different enrichment level, there are a lack of information regarding a uranium metal alloy, specifically UMo and UNbZr. Nowadays uranium metal alloy as fuel have been investigated under RERTR program as possible candidate to became a new fuel for research reactor due to high density. This work aim to evaluate a set of criticality safety parameters for uranium metal alloy using SCALE system and MCNP Monte Carlo code. (author)
Explicit Precedence Constraints in Safety-Critical Java
DEFF Research Database (Denmark)
Puffitsch, Wolfgang; Noulard, Eric; Pagetti, Claire
2013-01-01
Safety-critical Java (SCJ) aims at making the amenities of Java available for the development of safety-critical applications. The multi-rate synchronous language Prelude facilitates the specification of the communication and timing requirements of complex real-time systems. This paper combines...... to provide explicit support for precedence constraints. We present the considerations behind the design of this extension and discuss our experiences with a first prototype implementation based on the SCJ implementation of the Java Optimized Processor....
Criticality Safety in the Handling of Fissile Material. Specific Safety Guide
Energy Technology Data Exchange (ETDEWEB)
NONE
2014-05-15
This Safety Guide provides guidance and recommendations on how to meet the relevant requirements for ensuring subcriticality when dealing with fissile material and for planning the response to criticality accidents. The guidance and recommendations are applicable to both regulatory bodies and operating organizations. The objectives of criticality safety are to prevent a self-sustained nuclear chain reaction and to minimize the consequences of this if it were to occur. The Safety Guide makes recommendations on how to ensure subcriticality in systems involving fissile materials during normal operation, anticipated operational occurrences, and, in the case of accident conditions, within design basis accidents, from initial design through commissioning, operation, and decommissioning and disposal.
HSE's safety assessment principles for criticality safety
International Nuclear Information System (INIS)
Simister, D N; Finnerty, M D; Warburton, S J; Thomas, E A; Macphail, M R
2008-01-01
The Health and Safety Executive (HSE) published its revised Safety Assessment Principles for Nuclear Facilities (SAPs) in December 2006. The SAPs are primarily intended for use by HSE's inspectors when judging the adequacy of safety cases for nuclear facilities. The revised SAPs relate to all aspects of safety in nuclear facilities including the technical discipline of criticality safety. The purpose of this paper is to set out for the benefit of a wider audience some of the thinking behind the final published words and to provide an insight into the development of UK regulatory guidance. The paper notes that it is HSE's intention that the Safety Assessment Principles should be viewed as a reflection of good practice in the context of interpreting primary legislation such as the requirements under site licence conditions for arrangements for producing an adequate safety case and for producing a suitable and sufficient risk assessment under the Ionising Radiations Regulations 1999 (SI1999/3232 www.opsi.gov.uk/si/si1999/uksi_19993232_en.pdf). (memorandum)
Diversity requirements for safety critical software-based automation systems
International Nuclear Information System (INIS)
Korhonen, J.; Pulkkinen, U.; Haapanen, P.
1998-03-01
System vendors nowadays propose software-based systems even for the most critical safety functions in nuclear power plants. Due to the nature and mechanisms of influence of software faults new methods are needed for the safety and reliability evaluation of these systems. In the research project 'Programmable automation systems in nuclear power plants (OHA)' various safety assessment methods and tools for software based systems are developed and evaluated. This report first discusses the (common cause) failure mechanisms in software-based systems, then defines fault-tolerant system architectures to avoid common cause failures, then studies the various alternatives to apply diversity and their influence on system reliability. Finally, a method for the assessment of diversity is described. Other recently published reports in OHA-report series handles the statistical reliability assessment of software based (STUK-YTO-TR 119), usage models in reliability assessment of software-based systems (STUK-YTO-TR 128) and handling of programmable automation in plant PSA-studies (STUK-YTO-TR 129)
48 CFR 209.270 - Aviation and ship critical safety items.
2010-10-01
... Requirements 209.270 Aviation and ship critical safety items. ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Aviation and ship critical safety items. 209.270 Section 209.270 Federal Acquisition Regulations System DEFENSE ACQUISITION...
Nuclear criticality safety program at the Fuel Cycle Facility
International Nuclear Information System (INIS)
Lell, R.M.; Fujita, E.K.; Tracy, D.B.; Klann, R.T.; Imel, G.R.; Benedict, R.W.; Rigg, R.H.
1994-01-01
The Fuel Cycle Facility (FCF) is designed to demonstrate the feasibility of a novel commercial-scale remote pyrometallurgical process for metallic fuels from liquid metal-cooled reactors and to show closure of the Integral Fast Reactor (IFR) fuel cycle. Requirements for nuclear criticality safety impose the most restrictive of the various constraints on the operation of FCF. The upper limits on batch sizes and other important process parameters are determined principally by criticality safety considerations. To maintain an efficient operation within appropriate safety limits, it is necessary to formulate a nuclear criticality safety program that integrates equipment design, process development, process modeling, conduct of operations, a measurement program, adequate material control procedures, and nuclear criticality analysis. The nuclear criticality safety program for FCF reflects this integration, ensuring that the facility can be operated efficiently without compromising safety. The experience gained from the conduct of this program in the Fuel cycle Facility will be used to design and safely operate IFR facilities on a commercial scale. The key features of the nuclear criticality safety program are described. The relationship of these features to normal facility operation is also described
Review of WHC criticality safety audit findings for 1970-1981
International Nuclear Information System (INIS)
Rogers, C.A.; Paglieri, J.N.
1984-01-01
At Westinghouse Hanford Company (WHC) all fissionable material handling must meet DOE requirements for safety. This necessitates a program of regular audits by the Safety group to verify compliance with criticality safety limits and controls and to alert facility management to observed discrepancies and potential problems. Audits of fissionable material facilities by Safety are required at least once every 6 months, but in practice are conducted more frequently. This paper summarizes findings from over 400 criticality safety audits conducted by Safety between July 1970 and July 1981 in seven fissionable material facilities to show their types and frequencies of occurrence. All limit violations occurring during this period are summarized, including those found by the operating group. 1 ref., 1 tab
A software engineering process for safety-critical software application
International Nuclear Information System (INIS)
Kang, Byung Heon; Kim, Hang Bae; Chang, Hoon Seon; Jeon, Jong Sun
1995-01-01
Application of computer software to safety-critical systems in on the increase. To be successful, the software must be designed and constructed to meet the functional and performance requirements of the system. For safety reason, the software must be demonstrated not only to meet these requirements, but also to operate safely as a component within the system. For longer-term cost consideration, the software must be designed and structured to ease future maintenance and modifications. This paper presents a software engineering process for the production of safety-critical software for a nuclear power plant. The presentation is expository in nature of a viable high quality safety-critical software development. It is based on the ideas of a rational design process and on the experience of the adaptation of such process in the production of the safety-critical software for the shutdown system number two of Wolsung 2, 3 and 4 nuclear power generation plants. This process is significantly different from a conventional process in terms of rigorous software development phases and software design techniques, The process covers documentation, design, verification and testing using mathematically precise notations and highly reviewable tabular format to specify software requirements and software requirements and software requirements and code against software design using static analysis. The software engineering process described in this paper applies the principle of information-hiding decomposition in software design using a modular design technique so that when a change is required or an error is detected, the affected scope can be readily and confidently located. it also facilitates a sense of high degree of confidence in the 'correctness' of the software production, and provides a relatively simple and straightforward code implementation effort. 1 figs., 10 refs. (Author)
Nuclear criticality safety guide
International Nuclear Information System (INIS)
Pruvost, N.L.; Paxton, H.C.
1996-09-01
This technical reference document cites information related to nuclear criticality safety principles, experience, and practice. The document also provides general guidance for criticality safety personnel and regulators
Nuclear criticality safety guide
Energy Technology Data Exchange (ETDEWEB)
Pruvost, N.L.; Paxton, H.C. [eds.
1996-09-01
This technical reference document cites information related to nuclear criticality safety principles, experience, and practice. The document also provides general guidance for criticality safety personnel and regulators.
Prerequisites of ideal safety-critical organizations
International Nuclear Information System (INIS)
Takeuchi, Michiru; Hikono, Masaru; Matsui, Yuko; Goto, Manabu; Sakuda, Hiroshi
2013-01-01
This study explores the prerequisites of ideal safety-critical organizations, marshalling arguments of 4 areas of organizational research on safety, each of which has overlap: a safety culture, high reliability organizations (HROs), organizational resilience, and leadership especially in safety-critical organizations. The approach taken in this study was to retrieve questionnaire items or items on checklists of the 4 research areas and use them as materials of abduction (as referred to in the KJ method). The results showed that the prerequisites of ideal safety-oriented organizations consist of 9 factors as follows: (1) The organization provides resources and infrastructure to ensure safety. (2) The organization has a sharable vision. (3) Management attaches importance to safety. (4) Employees openly communicate issues and share wide-ranging information with each other. (5) Adjustments and improvements are made as the organization's situation changes. (6) Learning activities from mistakes and failures are performed. (7) Management creates a positive work environment and promotes good relations in the workplace. (8) Workers have good relations in the workplace. (9) Employees have all the necessary requirements to undertake their own functions, and act conservatively. (author)
A formal safety analysis for PLC software-based safety critical system using Z
International Nuclear Information System (INIS)
Koh, Jung Soo
1997-02-01
This paper describes a formal safety analysis technique which is demonstrated by performing empirical formal safety analysis with the case study of beamline hutch door Interlock system that is developed by using PLC (Programmable Logic Controller) systems at the Pohang Accelerator Laboratory. In order to perform formal safety analysis, we have built the Z formal specifications representation from user requirement written in ambiguous natural language and target PLC ladder logic, respectively. We have also studied the effective method to express typical PLC timer component by using specific Z formal notation which is supported by temporal history. We present a formal proof technique specifying and verifying that the hazardous states are not introduced into ladder logic in the PLC-based safety critical system. And also, we have found that some errors or mismatches in user requirement and final implemented PLC ladder logic while analyzing the process of the consistency and completeness of Z translated formal specifications. In the case of relatively small systems like Beamline hutch door interlock system, a formal safety analysis including explicit proof is highly recommended so that the safety of PLC-based critical system may be enhanced and guaranteed. It also provides a helpful benefits enough to comprehend user requirement expressed by ambiguous natural language
Product Engineering Class in the Software Safety Risk Taxonomy for Building Safety-Critical Systems
Hill, Janice; Victor, Daniel
2008-01-01
When software safety requirements are imposed on legacy safety-critical systems, retrospective safety cases need to be formulated as part of recertifying the systems for further use and risks must be documented and managed to give confidence for reusing the systems. The SEJ Software Development Risk Taxonomy [4] focuses on general software development issues. It does not, however, cover all the safety risks. The Software Safety Risk Taxonomy [8] was developed which provides a construct for eliciting and categorizing software safety risks in a straightforward manner. In this paper, we present extended work on the taxonomy for safety that incorporates the additional issues inherent in the development and maintenance of safety-critical systems with software. An instrument called a Software Safety Risk Taxonomy Based Questionnaire (TBQ) is generated containing questions addressing each safety attribute in the Software Safety Risk Taxonomy. Software safety risks are surfaced using the new TBQ and then analyzed. In this paper we give the definitions for the specialized Product Engineering Class within the Software Safety Risk Taxonomy. At the end of the paper, we present the tool known as the 'Legacy Systems Risk Database Tool' that is used to collect and analyze the data required to show traceability to a particular safety standard
Energy Technology Data Exchange (ETDEWEB)
Yamanaka, Alan Joseph Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-10-13
Guidance has been requested from the Nuclear Criticality Safety Division (NCSD) regarding processes that involve 520 grams of fissionable material or less. This Level-3 evaluation was conducted and documented in accordance with NCS-AP-004 (Ref. 1), formerly NCS-GUIDE-01. This evaluation is being written as a generic evaluation for all operations that will be able to operate using a 520-gram mass limit. Implementation for specific operations will be performed using a Level 1 CSED, which will confirm and document that this CSED can be used for the specific operation as discussed in NCS-MEMO-17-007 (Ref. 2). This Level 3 CSED updates and supersedes the analysis performed in NCS-TECH-14-014 (Ref. 3).
Design aspects of safety critical instrumentation of nuclear installations
Energy Technology Data Exchange (ETDEWEB)
Swaminathan, P. [Electronics Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)]. E-mail: swamy@igcar.ernet.in
2005-07-01
Safety critical instrumentation systems ensure safe shutdown/configuration of the nuclear installation when process status exceeds the safety threshold limits. Design requirements for safety critical instrumentation such as functional and electrical independence, fail-safe design, and architecture to ensure the specified unsafe failure rate and safe failure rate, human machine interface (HMI), etc., are explained with examples. Different fault tolerant architectures like 1/2, 2/2, 2/3 hot stand-by are compared for safety critical instrumentation. For embedded systems, software quality assurance is detailed both during design phase and O and M phase. Different software development models such as waterfall model and spiral model are explained with examples. The error distribution in embedded system is detailed. The usage of formal method is outlined to reduce the specification error. The guidelines for coding of application software are outlined. The interface problems of safety critical instrumentation with sensors, actuators, other computer systems, etc., are detailed with examples. Testability and maintainability shall be taken into account during design phase. Online diagnostics for safety critical instrumentation is detailed with examples. Salient details of design guides from Atomic Energy Regulatory Board, International Atomic Energy Agency and standards from IEEE, BIS are given towards the design of safety critical instrumentation systems. (author)
Design aspects of safety critical instrumentation of nuclear installations
International Nuclear Information System (INIS)
Swaminathan, P.
2005-01-01
Safety critical instrumentation systems ensure safe shutdown/configuration of the nuclear installation when process status exceeds the safety threshold limits. Design requirements for safety critical instrumentation such as functional and electrical independence, fail-safe design, and architecture to ensure the specified unsafe failure rate and safe failure rate, human machine interface (HMI), etc., are explained with examples. Different fault tolerant architectures like 1/2, 2/2, 2/3 hot stand-by are compared for safety critical instrumentation. For embedded systems, software quality assurance is detailed both during design phase and O and M phase. Different software development models such as waterfall model and spiral model are explained with examples. The error distribution in embedded system is detailed. The usage of formal method is outlined to reduce the specification error. The guidelines for coding of application software are outlined. The interface problems of safety critical instrumentation with sensors, actuators, other computer systems, etc., are detailed with examples. Testability and maintainability shall be taken into account during design phase. Online diagnostics for safety critical instrumentation is detailed with examples. Salient details of design guides from Atomic Energy Regulatory Board, International Atomic Energy Agency and standards from IEEE, BIS are given towards the design of safety critical instrumentation systems. (author)
Influence of safeguards and fire protection on criticality safety
International Nuclear Information System (INIS)
Six, D.E.
1980-01-01
There are several positive influences of safeguards and fire protection on criticality safety. Experts in each discipline must be aware of regulations and requirements of the others and work together to ensure a fault-tree design. EG and G Idaho, Inc., routinely uses an Occupancy-Use Readiness Manual to consider all aspects of criticality safety, fire protection, and safeguards. The use of the analytical tree is described
Validation testing of safety-critical software
International Nuclear Information System (INIS)
Kim, Hang Bae; Han, Jae Bok
1995-01-01
A software engineering process has been developed for the design of safety critical software for Wolsung 2/3/4 project to satisfy the requirements of the regulatory body. Among the process, this paper described the detail process of validation testing performed to ensure that the software with its hardware, developed by the design group, satisfies the requirements of the functional specification prepared by the independent functional group. To perform the tests, test facility and test software were developed and actual safety system computer was connected. Three kinds of test cases, i.e., functional test, performance test and self-check test, were programmed and run to verify each functional specifications. Test failures were feedback to the design group to revise the software and test results were analyzed and documented in the report to submit to the regulatory body. The test methodology and procedure were very efficient and satisfactory to perform the systematic and automatic test. The test results were also acceptable and successful to verify the software acts as specified in the program functional specification. This methodology can be applied to the validation of other safety-critical software. 2 figs., 2 tabs., 14 refs. (Author)
Nuclear Criticality Safety Organization qualification program. Revision 4
International Nuclear Information System (INIS)
Carroll, K.J.; Taylor, R.G.; Worley, C.A.
1997-01-01
The Nuclear Criticality Safety Organization (NCSO) is committed to developing and maintaining a staff of highly qualified personnel to meet the current and anticipated needs in Nuclear Criticality Safety (NCS) at the Oak Ridge Y-12 Plant. This document defines the Qualification Program to address the NCSO technical and managerial qualification as required by the Y-12 Training Implementation Matrix (TIM). It is implemented through a combination of LMES plant-wide training courses and professional nuclear criticality safety training provided within the organization. This Qualification Program is applicable to technical and managerial NCSO personnel, including temporary personnel, sub-contractors and/or LMES employees on loan to the NCSO, who perform the NCS tasks or serve NCS-related positions as defined in sections 5 and 6 of this program
Nuclear criticality safety specialist training and qualification programs
International Nuclear Information System (INIS)
Hopper, C.M.
1993-01-01
Since the beginning of the Nuclear Criticality Safety Division of the American Nuclear Society (ANS) in 1967, the nuclear criticality safety (NCS) community has sought to provide an exchange of information at a national level to facilitate the education and development of NCS specialists. In addition, individual criticality safety organizations within government contractor and licensed commercial nonreactor facilities have developed training and qualification programs for their NCS specialists. However, there has been substantial variability in the content and quality of these program requirements and personnel qualifications, at least as measured within the government contractor community. The purpose of this paper is to provide a brief, general history of staff training and to describe the current direction and focus of US DOE guidance for the content of training and qualification programs designed to develop NCS specialists
Development of High-Level Safety Requirements for a Pyroprocessing Facility
Energy Technology Data Exchange (ETDEWEB)
Seo, Seok Jun; Jo, Woo Jin; You, Gil Sung; Choung, Won Myung; Lee, Ho Hee; Kim, Hyun Min; Jeon, Hong Rae; Ku, Jeong Hoe; Lee, Hyo Jik [KAERI, Daejeon (Korea, Republic of)
2016-05-15
Korea Atomic Energy Research Institute (KAERI) has been developing a pyroproceesing technology to reduce the waste volume and recycle some elements. The pyroprocessing includes several treatment processes which are related with not only radiological and physical but also chemical and electrochemical properties. Thus, it is of importance to establish safety design requirements considering all the aspects of those properties for a reliable pyroprocessing facility. In this study, high-level requirements are presented in terms of not only radiation protection, nuclear criticality, fire protection, and seismic safety but also confinement and chemical safety for the unique characteristics of a pyroprocessing facility. Several high-level safety design requirements such as radiation protection, nuclear criticality, fire protection, seismic, confinement, and chemical processing were presented for a pyroprocessing facility. The requirements must fulfill domestic and international safety technology standards for a nuclear facility. Furthermore, additional requirements should be considered for the unique electrochemical treatments in a pyroprocessing facility.
Review of studies on criticality safety evaluation and criticality experiment methods
International Nuclear Information System (INIS)
Naito, Yoshitaka; Yamamoto, Toshihiro; Misawa, Tsuyoshi; Yamane, Yuichi
2013-01-01
Since the early 1960s, many studies on criticality safety evaluation have been conducted in Japan. Computer code systems were developed initially by employing finite difference methods, and more recently by using Monte Carlo methods. Criticality experiments have also been carried out in many laboratories in Japan as well as overseas. By effectively using these study results, the Japanese Criticality Safety Handbook was published in 1988, almost the intermediate point of the last 50 years. An increased interest has been shown in criticality safety studies, and a Working Party on Nuclear Criticality Safety (WPNCS) was set up by the Nuclear Science Committee of Organisation Economic Co-operation and Development in 1997. WPNCS has several task forces in charge of each of the International Criticality Safety Benchmark Evaluation Program (ICSBEP), Subcritical Measurement, Experimental Needs, Burn-up Credit Studies and Minimum Critical Values. Criticality safety studies in Japan have been carried out in cooperation with WPNCS. This paper describes criticality safety study activities in Japan along with the contents of the Japanese Criticality Safety Handbook and the tasks of WPNCS. (author)
ICSBEP-2007, International Criticality Safety Benchmark Experiment Handbook
International Nuclear Information System (INIS)
Blair Briggs, J.
2007-01-01
1 - Description: The Critically Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the United Sates Department of Energy. The project quickly became an international effort as scientist from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) is now an official activity of the Organization of Economic Cooperation and Development - Nuclear Energy Agency (OECD-NEA). This handbook contains criticality safety benchmark specifications that have been derived from experiments that were performed at various nuclear critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculational techniques used to establish minimum subcritical margins for operations with fissile material. The example calculations presented do not constitute a validation of the codes or cross section data. The work of the ICSBEP is documented as an International Handbook of Evaluated Criticality Safety Benchmark Experiments. Currently, the handbook spans over 42,000 pages and contains 464 evaluations representing 4,092 critical, near-critical, or subcritical configurations and 21 criticality alarm placement/shielding configurations with multiple dose points for each and 46 configurations that have been categorized as fundamental physics measurements that are relevant to criticality safety applications. The handbook is intended for use by criticality safety analysts to perform necessary validations of their calculational techniques and is expected to be a valuable tool for decades to come. The ICSBEP Handbook is available on DVD. You may request a DVD by completing the DVD Request Form on the internet. Access to the Handbook on the Internet requires a password. You may request a password by completing the Password Request Form. The Web address is: http://icsbep.inel.gov/handbook.shtml 2 - Method of solution: Experiments that are found
Request from nuclear fuel cycle and criticality safety design
International Nuclear Information System (INIS)
Hamasaki, Manabu; Sakashita, Kiichiro; Natsume, Toshihiro
2005-01-01
The quality and reliability of criticality safety design of nuclear fuel cycle systems such as fuel fabrication facilities, fuel reprocessing facilities, storage systems of various forms of nuclear materials or transportation casks have been largely dependent on the quality of criticality safety analyses using qualified criticality calculation code systems and reliable nuclear data sets. In this report, we summarize the characteristics of the nuclear fuel cycle systems and the perspective of the requirements for the nuclear data, with brief comments on the recent issue about spent fuel disposal. (author)
Nuclear criticality safety guide
International Nuclear Information System (INIS)
Ro, Seong Ki; Shin, Hee Seong; Park, Seong Won; Shin, Young Joon.
1997-06-01
Nuclear criticality safety guide was described for handling, transportation and storage of nuclear fissile materials in this report. The major part of the report was excerpted frp, TID-7016(revision 2) and nuclear criticality safety written by Knief. (author). 16 tabs., 44 figs., 5 refs
French safety and criticality testing programmes
International Nuclear Information System (INIS)
Barbry, F.; Leclerc, J.; Manaranche, J.C.; Maubert, L.
1982-01-01
This article underlines the need to include experimental safety-criticality programmes in the French nuclear effort. The means and methods used at the Section of Experimental Nuclear Safety and Criticality Research, attached to the CEA Valduc Centre, are described. Three experimental programmes are presented: safety-criticality of the PWR fuel cycle, neutron poisoning of plutonium solutions by gadolinium and safety-criticality of slightly enriched and slightly moderated uranium oxide. Criticality accidents studies in solution are then described [fr
Analysis of Critical Characteristics for Safety Graded Personnel Computers in the KNICS Architecture
International Nuclear Information System (INIS)
Lee, Hyun Chul; Lee, Dong Young
2009-01-01
Critical characteristics analysis of a safety related item is to identify characteristics to be verified to replace an original item with the dedicated item. It is sure that the dedicated item meeting critical characteristics would perform its intended safety function instead of the specified item. KNICS project developed two safety systems: IDiPS RPS (Reactor Protection System) and IDiPS ESF-CCS (Engineered Safety Features-Component Control System). Two safety systems of IDiPS are equipped with personnel computers, so-called COMs (Cabinet Operator Modules), in their cabinets. The personnel computers, COMs, are responsible for safety system monitoring, testing, and maintaining. Even though two safety systems are safety critical system, the personnel computers of two systems, i.e. COMs, are not graded as safety-graded items. Regulation requirements are expected to be strengthened, and the functions of the personnel computer may be enhanced to include safety-related functions and safety functions, it would be necessary that the grade of the personnel computers is adjusted to a higher level, the safety grade. To try to upgrade a non safety system, i.e. COMs, to a safety system, its safety functions and requirements, i.e. critical characteristics, must be identified and verified. This paper describes the process of the identification of critical characteristics and the results of analysis
Nuclear data for criticality safety
International Nuclear Information System (INIS)
Westfall, R.M.
1994-01-01
A brief overview is presented on emerging requirements for new criticality safety analyses arising from applications involving nuclear waste management, facility remediation, and the storage of nuclear weapons components. A derivation of criticality analyses from the specifications of national consensus standards is given. These analyses, both static and dynamic, define the needs for nuclear data. Integral data, used primarily for analytical validation, and differential data, used in performing the analyses, are listed, along with desirable margins of uncertainty. Examples are given of needs for additional data to address systems having intermediate neutron energy spectra and/or containing nuclides of intermediate mass number
A study on quantitative V and V of safety-critical software
International Nuclear Information System (INIS)
Eom, H. S.; Kang, H. G.; Chang, S. C.; Ha, J. J.; Son, H. S.
2004-03-01
Recently practical needs have required quantitative features for the software reliability for Probabilistic Safety Assessment which is one of the important methods being used in assessing the overall safety of nuclear power plant. But the conventional assessment methods of software reliability could not provide enough information for PSA of NPP, therefore current assessments of a digital system which includes safety-critical software usually exclude the software part or use arbitrary values. This paper describes a Bayesian Belief Networks based method that models the rule-based qualitative software assessment method for a practical use and can produce quantitative results for PSA. The framework was constructed by utilizing BBN that can combine the qualitative and quantitative evidence relevant to the reliability of safety-critical software and can infer a conclusion in a formal and a quantitative way. The case study was performed by applying the method for assessing the quality of software requirement specification of safety-critical software that will be embedded in reactor protection system
Criticality Safety Basics for INL FMHs and CSOs
Energy Technology Data Exchange (ETDEWEB)
V. L. Putman
2012-04-01
Nuclear power is a valuable and efficient energy alternative in our energy-intensive society. However, material that can generate nuclear power has properties that require this material be handled with caution. If improperly handled, a criticality accident could result, which could severely harm workers. This document is a modular self-study guide about Criticality Safety Principles. This guide's purpose it to help you work safely in areas where fissionable nuclear materials may be present, avoiding the severe radiological and programmatic impacts of a criticality accident. It is designed to stress the fundamental physical concepts behind criticality controls and the importance of criticality safety when handling fissionable materials outside nuclear reactors. This study guide was developed for fissionable-material-handler and criticality-safety-officer candidates to use with related web-based course 00INL189, BEA Criticality Safety Principles, and to help prepare for the course exams. These individuals must understand basic information presented here. This guide may also be useful to other Idaho National Laboratory personnel who must know criticality safety basics to perform their assignments safely or to design critically safe equipment or operations. This guide also includes additional information that will not be included in 00INL189 tests. The additional information is in appendices and paragraphs with headings that begin with 'Did you know,' or with, 'Been there Done that'. Fissionable-material-handler and criticality-safety-officer candidates may review additional information at their own discretion. This guide is revised as needed to reflect program changes, user requests, and better information. Issued in 2006, Revision 0 established the basic text and integrated various programs from former contractors. Revision 1 incorporates operation and program changes implemented since 2006. It also incorporates suggestions, clarifications
Computational methods for nuclear criticality safety analysis
International Nuclear Information System (INIS)
Maragni, M.G.
1992-01-01
Nuclear criticality safety analyses require the utilization of methods which have been tested and verified against benchmarks results. In this work, criticality calculations based on the KENO-IV and MCNP codes are studied aiming the qualification of these methods at the IPEN-CNEN/SP and COPESP. The utilization of variance reduction techniques is important to reduce the computer execution time, and several of them are analysed. As practical example of the above methods, a criticality safety analysis for the storage tubes for irradiated fuel elements from the IEA-R1 research has been carried out. This analysis showed that the MCNP code is more adequate for problems with complex geometries, and the KENO-IV code shows conservative results when it is not used the generalized geometry option. (author)
Utilization of the MCNP-3A code for criticality safety analysis
International Nuclear Information System (INIS)
Maragni, M.G.; Moreira, J.M.L.
1996-01-01
In the last decade, Brazil started to operate facilities for processing and storing uranium in different forms. The necessity of criticality safety analysis appeared in the design phase of the uranium pilot process plants and also in the licensing of transportation and storage of fissile materials. The 2-MW research reactor and the Angra I power plant also required criticality safety assessments because their spent-fuel storage was approaching full-capacity utilization. The criticality safety analysis in Brazil has been based on KENO IV code calculations, which present some difficulties for correct geometry representation. The MCNP-3A code is not reported to be used frequently for criticality safety analysis in Brazil, but its good geometry representation makes it a possible tool for treating problems of complex geometry. A set of benchmark tests was performed to verify its applicability for criticality safety analysis in Brazil. This paper presents several benchmark tests aimed at selecting a set of options available in the MCNP-3A code that would be adequate for criticality safety analysis. The MCNP-3A code is also compared with the KENO-IV code regarding its performance for criticality safety analysis
International handbook of evaluated criticality safety benchmark experiments
International Nuclear Information System (INIS)
2010-01-01
The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the United States Department of Energy. The project quickly became an international effort as scientists from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) became an official activity of the Organization for Economic Cooperation and Development - Nuclear Energy Agency (OECD-NEA) in 1995. This handbook contains criticality safety benchmark specifications that have been derived from experiments performed at various nuclear critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculational techniques used to establish minimum subcritical margins for operations with fissile material and to determine criticality alarm requirement and placement. Many of the specifications are also useful for nuclear data testing. Example calculations are presented; however, these calculations do not constitute a validation of the codes or cross section data. The evaluated criticality safety benchmark data are given in nine volumes. These volumes span over 55,000 pages and contain 516 evaluations with benchmark specifications for 4,405 critical, near critical, or subcritical configurations, 24 criticality alarm placement / shielding configurations with multiple dose points for each, and 200 configurations that have been categorized as fundamental physics measurements that are relevant to criticality safety applications. Experiments that are found unacceptable for use as criticality safety benchmark experiments are discussed in these evaluations; however, benchmark specifications are not derived for such experiments (in some cases models are provided in an appendix). Approximately 770 experimental configurations are categorized as unacceptable for use as criticality safety benchmark experiments. Additional evaluations are in progress and will be
Module Testing Techniques for Nuclear Safety Critical Software Using LDRA Testing Tool
International Nuclear Information System (INIS)
Moon, Kwon-Ki; Kim, Do-Yeon; Chang, Hoon-Seon; Chang, Young-Woo; Yun, Jae-Hee; Park, Jee-Duck; Kim, Jae-Hack
2006-01-01
The safety critical software in the I and C systems of nuclear power plants requires high functional integrity and reliability. To achieve those requirement goals, the safety critical software should be verified and tested according to related codes and standards through verification and validation (V and V) activities. The safety critical software testing is performed at various stages during the development of the software, and is generally classified as three major activities: module testing, system integration testing, and system validation testing. Module testing involves the evaluation of module level functions of hardware and software. System integration testing investigates the characteristics of a collection of modules and aims at establishing their correct interactions. System validation testing demonstrates that the complete system satisfies its functional requirements. In order to generate reliable software and reduce high maintenance cost, it is important that software testing is carried out at module level. Module testing for the nuclear safety critical software has rarely been performed by formal and proven testing tools because of its various constraints. LDRA testing tool is a widely used and proven tool set that provides powerful source code testing and analysis facilities for the V and V of general purpose software and safety critical software. Use of the tool set is indispensable where software is required to be reliable and as error-free as possible, and its use brings in substantial time and cost savings, and efficiency
International Nuclear Information System (INIS)
Umeda, Miki; Sugikawa, Susumu; Nakamura, Kazuhito; Egashira, Tetsurou
1998-08-01
Design and construction of a plutonium dissolver using silver mediated electrolytic oxidation method are promoted in NUCEF. Criticality safety analysis for the plutonium dissolver is described in this report. The electrolytic plutonium dissolver consists of connection pipes and three pots for MOX powder supply, circulation and electrolysis. The criticality control for the dissolver is made by geometrically safe shape with mass limitation. Monte Carlo code KENO-IV using MGCL-137 library based on ENDF/B-IV was used for the criticality safety analysis for the plutonium dissolver. Considering the required size for construction and criticality safety, diameter of pot and distance between two pots were determined. On this condition, the criticality safety analysis for the plutonium dissolver with connection pipes was carried out. As the result of the criticality safety analysis, an effective neutron multiplication factor keff of 0.91 was obtained and the criticality safety of the plutonium dissolver was confirmed on the basis of criteria of ≤0.95. (author)
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
Nuclear criticality safety: 2-day training course
International Nuclear Information System (INIS)
Schlesser, J.A.
1997-02-01
This compilation of notes is presented as a source reference for the criticality safety course. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used as Los Alamos; be able to identify examples of circumstances present during criticality accidents; have participated in conducting two critical experiments; be asked to complete a critique of the nuclear criticality safety training course
Nuclear criticality safety: 2-day training course
Energy Technology Data Exchange (ETDEWEB)
Schlesser, J.A. [ed.] [comp.
1997-02-01
This compilation of notes is presented as a source reference for the criticality safety course. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used as Los Alamos; be able to identify examples of circumstances present during criticality accidents; have participated in conducting two critical experiments; be asked to complete a critique of the nuclear criticality safety training course.
International Nuclear Information System (INIS)
RAMBLE, A.L.
2000-01-01
The purpose of this document is to record the technical evaluation of the Operational Safety Requirements described in the Plutonium Finishing Plant Final (PFP) Operational Safety Requirements, WHC-SD-CP-OSR-010. Rev. 0-N , Section 3.1.1, ''Criticality Prevention System.'' This document, with its appendices, provides the following: (1) The results of a review of Criticality Safety Analysis Reports (CSAR), later called Criticality Safety Evaluation Reports (CSER), and Criticality Prevention Specifications (CPS) to determine which equipment or components analyzed in the CSER or CPS are considered as one of the two unlikely, independent, and concurrent changes before a criticality accident is possible. (2) Evaluations of equipment or components to determine the safety boundary for the system (Section 4). (3) A list of essential drawings that show the safety system or component (Appendix A). (4) A list of the safety envelope (SE) equipment (Appendix B). (5) Functional requirements for the individual safety envelope equipment (Sections 3 and 4). (6) A list of the operational and surveillance procedures necessary to maintain the system equipment within the safety envelope (Section 5)
Safety-critical Java for embedded systems
DEFF Research Database (Denmark)
Schoeberl, Martin; Dalsgaard, Andreas Engelbredt; Hansen, René Rydhof
2016-01-01
This paper presents the motivation for and outcomes of an engineering research project on certifiable Javafor embedded systems. The project supports the upcoming standard for safety-critical Java, which defines asubset of Java and libraries aiming for development of high criticality systems....... The outcome of this projectinclude prototype safety-critical Java implementations, a time-predictable Java processor, analysis tools formemory safety, and example applications to explore the usability of safety-critical Java for this applicationarea. The text summarizes developments and key contributions...
Outline of criticality safety research project
International Nuclear Information System (INIS)
Kobayashi, Iwao; Tachimori, Shoichi; Suzaki, Takenori; Takeshita, Isao; Miyoshi, Yoshinori; Nakajima, Ken; Sakurai, Satoshi; Yanagisawa, Hiroshi
1987-01-01
As the power generation capacity of LWRs in Japan increased, the establishment and development of nuclear fuel cycle have become the important subject. Conforming to the safety research project of the nation, the Japan Atomic Energy Research Institute has advanced the project of constructing a new research facility, that is, Nuclear Fuel Cycle Engineering Research Facility (NUCEF). In this facility, it is planned to carry out the research on criticality safety, upgraded reprocessing techniques, and the treatment and disposal of transuranium element wastes. In this paper, the subjects of criticality safety research and the research carried out with a criticality safety experiment facility which is expected to be installed in the NUCEF are briefly reported. The experimental data obtained from the criticality safety handbooks and published literatures in foreign countries are short of the data on the mixture of low enriched uranium and plutonium which is treated in the reprocessing of spent fuel from LWRs. The acquisition of the criticality data for various forms of fuel, the elucidation of the scenario of criticality accidents, and the soundness of the confinement system for gaseous fission products and plutonium are the main subjects. The Static Criticality Safety Facility, Transient Criticality Safety Facility and pulse column system are the main facilities. (Kako, I.)
NSPWG-recommended safety requirements and guidelines for SEI nuclear propulsion
International Nuclear Information System (INIS)
Marshall, A.C.; Lee, J.H.; McCulloch, W.H.; Sawyer, J.C. Jr.; Bari, R.A.; Brown, N.W.; Cullingford, H.S.; Hardy, A.C.; Remp, K.; Sholtis, J.A.
1992-01-01
An Interagency Nuclear Safety Policy Working Group (NSPWG) was chartered to recommend nuclear safety policy, requirements, and guidelines for the Space Exploration Initiative (SEI) nuclear propulsion program to facilitate the implementation of mission planning and conceptual design studies. The NSPWG developed a top- level policy to provide the guiding principles for the development and implementation of the nuclear propulsion safety program and the development of Safety Functional Requirements. In addition the NSPWG reviewed safety issues for nuclear propulsion and recommended top-level safety requirements and guidelines to address these issues. Safety requirements were developed for reactor start-up, inadvertent criticality, radiological release and exposure, disposal, entry, and safeguards. Guidelines were recommended for risk/reliability, operational safety, flight trajectory and mission abort, space debris and meteoroids, and ground test safety. In this paper the specific requirements and guidelines will be discussed
Overview of Risk Mitigation for Safety-Critical Computer-Based Systems
Torres-Pomales, Wilfredo
2015-01-01
This report presents a high-level overview of a general strategy to mitigate the risks from threats to safety-critical computer-based systems. In this context, a safety threat is a process or phenomenon that can cause operational safety hazards in the form of computational system failures. This report is intended to provide insight into the safety-risk mitigation problem and the characteristics of potential solutions. The limitations of the general risk mitigation strategy are discussed and some options to overcome these limitations are provided. This work is part of an ongoing effort to enable well-founded assurance of safety-related properties of complex safety-critical computer-based aircraft systems by developing an effective capability to model and reason about the safety implications of system requirements and design.
Nuclear criticality safety: 2-day training course
International Nuclear Information System (INIS)
Schlesser, J.A.
1992-11-01
This compilation of notes is presented as a source reference for the criticality safety course. At the completion of this training course, the attendee will: (1) be able to define terms commonly used in nuclear criticality safety; (2) be able to appreciate the fundamentals of nuclear criticality safety; (3) be able to identify factors which affect nuclear criticality safety; (4) be able to identify examples of criticality controls as used at Los Alamos; (5) be able to identify examples of circumstances present during criticality accidents; (6) have participated in conducting two critical experiments
International Nuclear Information System (INIS)
Lee, Jang Soo; Kim, Jang Yeol; Eum, Heung Seop.
1997-07-01
Recently, the safety planning for safety-critical software systems is being recognized as the most important phase in the software life cycle, and being developed new regulatory positions and standards by the regulatory and the standardization organization. The requirements for software important to safety of nuclear reactor are described in such positions and standards. Most of them are describing mandatory requirements, what shall be done, for the safety-critical software. The developers of such a software. However, there have been a lot of controversial factors on whether the work practices satisfy the regulatory requirements, and to justify the safety of such a system developed by the work practices, between the licenser and the licensee. We believe it is caused by the reason that there is a gap between the mandatory requirements (What) and the work practices (How). We have developed a guidance to fill such gap, which can be useful for both licenser and licensee to conduct a justification of the safety in the planning phase of developing the software for nuclear reactor protection systems. (author). 67 refs., 13 tabs., 2 figs
Energy Technology Data Exchange (ETDEWEB)
Lee, Jang Soo; Kim, Jang Yeol; Eum, Heung Seop
1997-07-01
Recently, the safety planning for safety-critical software systems is being recognized as the most important phase in the software life cycle, and being developed new regulatory positions and standards by the regulatory and the standardization organization. The requirements for software important to safety of nuclear reactor are described in such positions and standards. Most of them are describing mandatory requirements, what shall be done, for the safety-critical software. The developers of such a software. However, there have been a lot of controversial factors on whether the work practices satisfy the regulatory requirements, and to justify the safety of such a system developed by the work practices, between the licenser and the licensee. We believe it is caused by the reason that there is a gap between the mandatory requirements (What) and the work practices (How). We have developed a guidance to fill such gap, which can be useful for both licenser and licensee to conduct a justification of the safety in the planning phase of developing the software for nuclear reactor protection systems. (author). 67 refs., 13 tabs., 2 figs.
Security for safety critical space borne systems
Legrand, Sue
1987-01-01
The Space Station contains safety critical computer software components in systems that can affect life and vital property. These components require a multilevel secure system that provides dynamic access control of the data and processes involved. A study is under way to define requirements for a security model providing access control through level B3 of the Orange Book. The model will be prototyped at NASA-Johnson Space Center.
Software quality assurance plans for safety-critical software
International Nuclear Information System (INIS)
Liddle, P.
2006-01-01
Application software is defined as safety-critical if a fault in the software could prevent the system components from performing their nuclear-safety functions. Therefore, for nuclear-safety systems, the AREVA TELEPERM R XS (TXS) system is classified 1E, as defined in the Inst. of Electrical and Electronics Engineers (IEEE) Std 603-1998. The application software is classified as Software Integrity Level (SIL)-4, as defined in IEEE Std 7-4.3.2-2003. The AREVA NP Inc. Software Program Manual (SPM) describes the measures taken to ensure that the TELEPERM XS application software attains a level of quality commensurate with its importance to safety. The manual also describes how TELEPERM XS correctly performs the required safety functions and conforms to established technical and documentation requirements, conventions, rules, and standards. The program manual covers the requirements definition, detailed design, integration, and test phases for the TELEPERM XS application software, and supporting software created by AREVA NP Inc. The SPM is required for all safety-related TELEPERM XS system applications. The program comprises several basic plans and practices: 1. A Software Quality-Assurance Plan (SQAP) that describes the processes necessary to ensure that the software attains a level of quality commensurate with its importance to safety function. 2. A Software Safety Plan (SSP) that identifies the process to reasonably ensure that safety-critical software performs as intended during all abnormal conditions and events, and does not introduce any new hazards that could jeopardize the health and safety of the public. 3. A Software Verification and Validation (V and V) Plan that describes the method of ensuring the software is in accordance with the requirements. 4. A Software Configuration Management Plan (SCMP) that describes the method of maintaining the software in an identifiable state at all times. 5. A Software Operations and Maintenance Plan (SO and MP) that
The Dynamics of Agile Practices for Safety-Critical Software Development
DEFF Research Database (Denmark)
Nielsen, Peter Axel; Tordrup Heeager, Lise
2017-01-01
This short paper reports from a case study of the agile development of safety-critical software. It utilizes a framework of dynamic relationships between agile practices with the purpose of demonstrating the utility of the framework to understand a case in its context, and it shows significant...... dynamics. The study is concluded by pointing at which further research on the framework is required to use the framework in managing the agile development of safety-critical software....
Elements of a nuclear criticality safety program
International Nuclear Information System (INIS)
Hopper, C.M.
1995-01-01
Nuclear criticality safety programs throughout the United States are quite successful, as compared with other safety disciplines, at protecting life and property, especially when regarded as a developing safety function with no historical perspective for the cause and effect of process nuclear criticality accidents before 1943. The programs evolved through self-imposed and regulatory-imposed incentives. They are the products of conscientious individuals, supportive corporations, obliged regulators, and intervenors (political, public, and private). The maturing of nuclear criticality safety programs throughout the United States has been spasmodic, with stability provided by the volunteer standards efforts within the American Nuclear Society. This presentation provides the status, relative to current needs, for nuclear criticality safety program elements that address organization of and assignments for nuclear criticality safety program responsibilities; personnel qualifications; and analytical capabilities for the technical definition of critical, subcritical, safety and operating limits, and program quality assurance
Criticality safety evaluation in Tokai Reprocessing Plant
International Nuclear Information System (INIS)
Shirai, Nobutoshi; Nakajima, Masayoshi; Takaya, Akikazu; Ohnuma, Hideyuki; Shirouzu, Hidetomo; Hayashi, Shinichiro; Yoshikawa, Koji; Suto, Toshiyuki
2000-04-01
Criticality limits for equipments in Tokai Reprocessing Plant which handle fissile material solution and are under shape and dimension control were reevaluated based on the guideline No.10 'Criticality safety of single unit' in the regulatory guide for reprocessing plant safety. This report presents criticality safety evaluation of each equipment as single unit. Criticality safety of multiple units in a cell or a room was also evaluated. The evaluated equipments were ones in dissolution, separation, purification, denitration, Pu product storage, and Pu conversion processes. As a result, it was reconfirmed that the equipments were safe enough from a view point of criticality safety of single unit and multiple units. (author)
International Criticality Safety Benchmark Evaluation Project (ICSBEP) - ICSBEP 2015 Handbook
International Nuclear Information System (INIS)
Bess, John D.
2015-01-01
The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the United States Department of Energy (DOE). The project quickly became an international effort as scientists from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) became an official activity of the Nuclear Energy Agency (NEA) in 1995. This handbook contains criticality safety benchmark specifications that have been derived from experiments performed at various critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculation techniques used to establish minimum subcritical margins for operations with fissile material and to determine criticality alarm requirements and placement. Many of the specifications are also useful for nuclear data testing. Example calculations are presented; however, these calculations do not constitute a validation of the codes or cross-section data. The evaluated criticality safety benchmark data are given in nine volumes. These volumes span approximately 69000 pages and contain 567 evaluations with benchmark specifications for 4874 critical, near-critical or subcritical configurations, 31 criticality alarm placement/shielding configurations with multiple dose points for each, and 207 configurations that have been categorised as fundamental physics measurements that are relevant to criticality safety applications. New to the handbook are benchmark specifications for neutron activation foil and thermoluminescent dosimeter measurements performed at the SILENE critical assembly in Valduc, France as part of a joint venture in 2010 between the US DOE and the French Alternative Energies and Atomic Energy Commission (CEA). A photograph of this experiment is shown on the front cover. Experiments that are found unacceptable for use as criticality safety benchmark experiments are discussed in these
Safety of Research Reactors. Safety Requirements
International Nuclear Information System (INIS)
2010-01-01
The main objective of this Safety Requirements publication is to provide a basis for safety and a basis for safety assessment for all stages in the lifetime of a research reactor. Another objective is to establish requirements on aspects relating to regulatory control, the management of safety, site evaluation, design, operation and decommissioning. Technical and administrative requirements for the safety of research reactors are established in accordance with these objectives. This Safety Requirements publication is intended for use by organizations engaged in the site evaluation, design, manufacturing, construction, operation and decommissioning of research reactors as well as by regulatory bodies
Nuclear criticality safety handbook. Version 2
International Nuclear Information System (INIS)
1999-03-01
The Nuclear Criticality Safety Handbook, Version 2 essentially includes the description of the Supplement Report to the Nuclear Criticality Safety Handbook, released in 1995, into the first version of Nuclear Criticality Safety Handbook, published in 1988. The following two points are new: (1) exemplifying safety margins related to modelled dissolution and extraction processes, (2) describing evaluation methods and alarm system for criticality accidents. Revision is made based on previous studies for the chapter that treats modelling the fuel system: e.g., the fuel grain size that the system can be regarded as homogeneous, non-uniformity effect of fuel solution, and burnup credit. This revision solves the inconsistencies found in the first version between the evaluation of errors found in JACS code system and criticality condition data that were calculated based on the evaluation. (author)
Performance Testing Methodology for Safety-Critical Programmable Logic Controller
International Nuclear Information System (INIS)
Kim, Chang Ho; Oh, Do Young; Kim, Ji Hyeon; Kim, Sung Ho; Sohn, Se Do
2009-01-01
The Programmable Logic Controller (PLC) for use in Nuclear Power Plant safety-related applications is being developed and tested first time in Korea. This safety-related PLC is being developed with requirements of regulatory guideline and industry standards for safety system. To test that the quality of the developed PLC is sufficient to be used in safety critical system, document review and various product testings were performed over the development documents for S/W, H/W, and V/V. This paper provides the performance testing methodology and its effectiveness for PLC platform conducted by KOPEC
Quantitative reliability assessment for safety critical system software
International Nuclear Information System (INIS)
Chung, Dae Won; Kwon, Soon Man
2005-01-01
An essential issue in the replacement of the old analogue I and C to computer-based digital systems in nuclear power plants is the quantitative software reliability assessment. Software reliability models have been successfully applied to many industrial applications, but have the unfortunate drawback of requiring data from which one can formulate a model. Software which is developed for safety critical applications is frequently unable to produce such data for at least two reasons. First, the software is frequently one-of-a-kind, and second, it rarely fails. Safety critical software is normally expected to pass every unit test producing precious little failure data. The basic premise of the rare events approach is that well-tested software does not fail under normal routine and input signals, which means that failures must be triggered by unusual input data and computer states. The failure data found under the reasonable testing cases and testing time for these conditions should be considered for the quantitative reliability assessment. We will present the quantitative reliability assessment methodology of safety critical software for rare failure cases in this paper
Criticality safety basics, a study guide
Energy Technology Data Exchange (ETDEWEB)
V. L. Putman
1999-09-01
This document is a self-study and classroom guide, for criticality safety of activities with fissile materials outside nuclear reactors. This guide provides a basic overview of criticality safety and criticality accident prevention methods divided into three parts: theory, application, and history. Except for topic emphasis, theory and history information is general, while application information is specific to the Idaho National Engineering and Environmental Laboratory (INEEL). Information presented here should be useful to personnel who must know criticality safety basics to perform their assignments safely or to design critically safe equipment or operations. However, the guide's primary target audience is fissile material handler candidates.
Criticality safety basics, a study guide
International Nuclear Information System (INIS)
Putman, V.L.
1999-01-01
This document is a self-study and classroom guide, for criticality safety of activities with fissile materials outside nuclear reactors. This guide provides a basic overview of criticality safety and criticality accident prevention methods divided into three parts: theory, application, and history. Except for topic emphasis, theory and history information is general, while application information is specific to the Idaho National Engineering and Environmental Laboratory (INEEL). Information presented here should be useful to personnel who must know criticality safety basics to perform their assignments safely or to design critically safe equipment or operations. However, the guide's primary target audience is fissile material handler candidates
Validation of calculational methods for nuclear criticality safety - approved 1975
International Nuclear Information System (INIS)
Anon.
1977-01-01
The American National Standard for Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors, N16.1-1975, states in 4.2.5: In the absence of directly applicable experimental measurements, the limits may be derived from calculations made by a method shown to be valid by comparison with experimental data, provided sufficient allowances are made for uncertainties in the data and in the calculations. There are many methods of calculation which vary widely in basis and form. Each has its place in the broad spectrum of problems encountered in the nuclear criticality safety field; however, the general procedure to be followed in establishing validity is common to all. The standard states the requirements for establishing the validity and area(s) of applicability of any calculational method used in assessing nuclear criticality safety
Energy Technology Data Exchange (ETDEWEB)
Joo, Sungmoon; Suh, Yong-Suk; Park, Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2016-10-15
This study was motivated by a research reactor project where the owner of the project and the equipment vendors are from two different standards frameworks. This paper reviews two major standards frameworks - NRC-IEEE and IAEA-IEC - and the software classification schemes as a background, then discuss the V and V issue. The purpose of this paper is by no means to solve the cross-standards-framework qualification issue, but, rather, is to remind the stakeholders of research reactor projects. V and V are also essential for the approval from regulatory bodies. As standards define or recommend consolidated engineering practices, methods, or criteria, V and V activities for software qualification are not exceptional. Within a standards framework, usually, the processes for the qualification of safety-critical software are well-established such that the safety is maximized while minimizing the compromises in software quality, safety, and reliability. When, however, multiple standards frameworks are involved in a research reactor project, it is difficult for equipment vendors to implement appropriate V and V activities as there is no unified view on this cross-standards-framework qualification issue yet. There are two major standards frameworks for safety-critical software development in nuclear industry. Unfortunately different safety classifications for software and thus different requirements for qualification are in place. What makes things worse is that (i) there are ambiguities in the standards and rooms for each stakeholders’ interpretation, and (ii) there is no one-to-one mapping between the associated V and V methods and activities. These may put the stakeholders of research reactor projects in trouble.
International Nuclear Information System (INIS)
Joo, Sungmoon; Suh, Yong-Suk; Park, Cheol
2016-01-01
This study was motivated by a research reactor project where the owner of the project and the equipment vendors are from two different standards frameworks. This paper reviews two major standards frameworks - NRC-IEEE and IAEA-IEC - and the software classification schemes as a background, then discuss the V and V issue. The purpose of this paper is by no means to solve the cross-standards-framework qualification issue, but, rather, is to remind the stakeholders of research reactor projects. V and V are also essential for the approval from regulatory bodies. As standards define or recommend consolidated engineering practices, methods, or criteria, V and V activities for software qualification are not exceptional. Within a standards framework, usually, the processes for the qualification of safety-critical software are well-established such that the safety is maximized while minimizing the compromises in software quality, safety, and reliability. When, however, multiple standards frameworks are involved in a research reactor project, it is difficult for equipment vendors to implement appropriate V and V activities as there is no unified view on this cross-standards-framework qualification issue yet. There are two major standards frameworks for safety-critical software development in nuclear industry. Unfortunately different safety classifications for software and thus different requirements for qualification are in place. What makes things worse is that (i) there are ambiguities in the standards and rooms for each stakeholders’ interpretation, and (ii) there is no one-to-one mapping between the associated V and V methods and activities. These may put the stakeholders of research reactor projects in trouble
Energy Technology Data Exchange (ETDEWEB)
NONE
2015-04-15
This handbook was prepared primarily with the aim to provide information to experts in industry, authorities or research facilities engaged in criticality-safety-related problems that will allow an adequate and rapid assessment of criticality safety issues already in the planning and preparation of nuclear facilities. However, it is not the intention of the authors of the handbook to offer ready solutions to complex problems of nuclear safety. Such questions have to remain subject to an in-depth analysis and assessment to be carried out by dedicated criticality safety experts. Compared with the previous edition dated December 1998, this handbook has been further revised and supplemented. The proven basic structure of the handbook remains unchanged. The handbook follows in some ways similar criticality handbooks or instructions published in the USA, UK, France, Japan and the former Soviet Union. The expedient use of the information given in this handbook requires a fundamental understanding of criticality and the terminology of nuclear safety. In Vol. 1, ''Criticality and Nuclear Safety'', therefore, first the most important terms and fundamentals are introduced and explained. Subsequently, experimental techniques and calculation methods for evaluating criticality problems are presented. The following chapters of Vol. 1 deal i. a. with the effect of neutron reflectors and absorbers, neutron interaction, measuring methods for criticality, and organisational safety measures and provide an overview of criticality-relevant operational experience and of criticality accidents and their potential hazardous impact. Vol. 2 parts 1 and 2 finally compile criticality parameters in graphical and tabular form. The individual graph sheets are provided with an initially explained set of identifiers, to allow the quick finding of the information of current interest. Part 1 includes criticality parameters for systems with {sup 235}U as fissile material, while part
Using fuzzy self-organising maps for safety critical systems
International Nuclear Information System (INIS)
Kurd, Zeshan; Kelly, Tim P.
2007-01-01
This paper defines a type of constrained artificial neural network (ANN) that enables analytical certification arguments whilst retaining valuable performance characteristics. Previous work has defined a safety lifecycle for ANNs without detailing a specific neural model. Building on this previous work, the underpinning of the devised model is based upon an existing neuro-fuzzy system called the fuzzy self-organising map (FSOM). The FSOM is type of 'hybrid' ANN which allows behaviour to be described qualitatively and quantitatively using meaningful expressions. Safety of the FSOM is argued through adherence to safety requirements-derived from hazard analysis and expressed using safety constraints. The approach enables the construction of compelling (product-based) arguments for mitigation of potential failure modes associated with the FSOM. The constrained FSOM has been termed a 'safety critical artificial neural network' (SCANN). The SCANN can be used for non-linear function approximation and allows certified learning and generalisation for high criticality roles. A discussion of benefits for real-world applications is also presented
International Nuclear Information System (INIS)
1993-11-01
This document contains guidelines that should be followed when preparing Criticality Safety Evaluations that will be used to demonstrate the safety of operations performed at DOE non-reactor nuclear facilities. Adherence to these guidelines will provide consistency and uniformity in criticality safety evaluations (CSEs) across the complex and will document compliance with the requirements of DOE Order 5480.24
CTMCONTROL: Addressing the MC/DC Objective for Safety-Critical Automotive Software
Mjeda , Anila; Hinchey , Mike
2013-01-01
International audience; We propose a method tailored to the requirements of safety-critical embedded automotive software, named CTMCONTROL. CTMCONTROL has a par-ticular focus on the specification-based control logic of the system under test and offers improvements in testing coverage metrics over a classic method which is routinely used in industry. The proposed method targets the Modified Condition/ Decision Coverage (MC/DC) objective for automotive safety-critical software. CTMCONTROL is va...
Critical experiments facility and criticality safety programs at JAERI
International Nuclear Information System (INIS)
Kobayashi, Iwao; Tachimori, Shoichi; Takeshita, Isao; Suzaki, Takenori; Miyoshi, Yoshinori; Nomura, Yasushi
1985-10-01
The nuclear criticality safety is becoming a key point in Japan in the safety considerations for nuclear installations outside reactors such as spent fuel reprocessing facilities, plutonium fuel fabrication facilities, large scale hot alboratories, and so on. Especially a large scale spent fuel reprocessing facility is being designed and would be constructed in near future, therefore extensive experimental studies are needed for compilation of our own technical standards and also for verification of safety in a potential criticality accident to obtain public acceptance. Japan Atomic Energy Research Institute is proceeding a construction program of a new criticality safety experimental facility where criticality data can be obtained for such solution fuels as mainly handled in a reprocessing facility and also chemical process experiments can be performed to investigate abnormal phenomena, e.g. plutonium behavior in solvent extraction process by using pulsed colums. In FY 1985 detail design of the facility will be completed and licensing review by the government would start in FY 1986. Experiments would start in FY 1990. Research subjects and main specifications of the facility are described. (author)
System Guidelines for EMC Safety-Critical Circuits: Design, Selection, and Margin Demonstration
Lawton, R. M.
1996-01-01
Demonstration of safety margins for critical points (circuits) has traditionally been required since it first became a part of systems-level Electromagnetic Compatibility (EMC) requirements of MIL-E-6051C. The goal of this document is to present cost-effective guidelines for ensuring adequate Electromagnetic Effects (EME) safety margins on spacecraft critical circuits. It is for the use of NASA and other government agencies and their contractors to prevent loss of life, loss of spacecraft, or unacceptable degradation. This document provides practical definition and treatment guidance to contain costs within affordable limits.
An aspect-oriented approach for designing safety-critical systems
Petrov, Z.; Zaykov, P. G.; Cardoso, J. P.; Coutinho, J. G. F.; Diniz, P. C.; Luk, W.
The development of avionics systems is typically a tedious and cumbersome process. In addition to the required functions, developers must consider various and often conflicting non-functional requirements such as safety, performance, and energy efficiency. Certainly, an integrated approach with a seamless design flow that is capable of requirements modelling and supporting refinement down to an actual implementation in a traceable way, may lead to a significant acceleration of development cycles. This paper presents an aspect-oriented approach supported by a tool chain that deals with functional and non-functional requirements in an integrated manner. It also discusses how the approach can be applied to development of safety-critical systems and provides experimental results.
Autoclave nuclear criticality safety analysis
Energy Technology Data Exchange (ETDEWEB)
D`Aquila, D.M. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States); Tayloe, R.W. Jr. [Battelle, Columbus, OH (United States)
1991-12-31
Steam-heated autoclaves are used in gaseous diffusion uranium enrichment plants to heat large cylinders of UF{sub 6}. Nuclear criticality safety for these autoclaves is evaluated. To enhance criticality safety, systems are incorporated into the design of autoclaves to limit the amount of water present. These safety systems also increase the likelihood that any UF{sub 6} inadvertently released from a cylinder into an autoclave is not released to the environment. Up to 140 pounds of water can be held up in large autoclaves. This mass of water is sufficient to support a nuclear criticality when optimally combined with 125 pounds of UF{sub 6} enriched to 5 percent U{sup 235}. However, water in autoclaves is widely dispersed as condensed droplets and vapor, and is extremely unlikely to form a critical configuration with released UF{sub 6}.
Criticality safety engineering at the Savannah River Site - the 1990s
International Nuclear Information System (INIS)
Chandler, J.R.; Apperson, C.E. Jr.
1996-01-01
The privatization and downsizing effort that is ongoing within the U.S. Department of Energy (DOE) is requiring a change in the management of criticality safety engineering resources at the Savannah River Site (SRS). Downsizing affects the number of criticality engineers employed by the prime contractor, Westinghouse Savannah River Company (WSRC), and privatization affects the manner in which business is conducted. In the past, criticality engineers at the SRS have been part of the engineering organizations that support each facility handling fissile material. This practice led to different criticality safety engineering organizations dedicated to fuel fabrication activities, reactor loading and unloading activities, separation and waste management operations, and research and development
Anatomy of safety-critical computing problems
International Nuclear Information System (INIS)
Swu Yih; Fan Chinfeng; Shirazi, Behrooz
1995-01-01
This paper analyzes the obstacles faced by current safety-critical computing applications. The major problem lies in the difficulty to provide complete and convincing safety evidence to prove that the software is safe. We explain this problem from a fundamental perspective by analyzing the essence of safety analysis against that of software developed by current practice. Our basic belief is that in order to perform a successful safety analysis, the state space structure of the analyzed system must have some properties as prerequisites. We propose the concept of safety analyzability, and derive its necessary and sufficient conditions; namely, definability, finiteness, commensurability, and tractability. We then examine software state space structures against these conditions, and affirm that the safety analyzability of safety-critical software developed by current practice is severely restricted by its state space structure and by the problem of exponential growth cost. Thus, except for small and simple systems, the safety evidence may not be complete and convincing. Our concepts and arguments successfully explain the current problematic situation faced by the safety-critical computing domain. The implications are also discussed
International Nuclear Information System (INIS)
2013-01-01
The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the United States Department of Energy. The project quickly became an international effort as scientists from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) became an official activity of the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) in 1995. This handbook contains criticality safety benchmark specifications that have been derived from experiments performed at various nuclear critical experiment facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculational techniques used to establish minimum subcritical margins for operations with fissile material and to determine criticality alarm requirement and placement. Many of the specifications are also useful for nuclear data testing. Example calculations are presented; however, these calculations do not constitute a validation of the codes or cross section data. The evaluated criticality safety benchmark data are given in nine volumes. These volumes span nearly 66,000 pages and contain 558 evaluations with benchmark specifications for 4,798 critical, near critical or subcritical configurations, 24 criticality alarm placement/shielding configurations with multiple dose points for each and 200 configurations that have been categorised as fundamental physics measurements that are relevant to criticality safety applications. New to the Handbook are benchmark specifications for Critical, Bare, HEU(93.2)- Metal Sphere experiments referred to as ORSphere that were performed by a team of experimenters at Oak Ridge National Laboratory in the early 1970's. A photograph of this assembly is shown on the front cover
International Nuclear Information System (INIS)
THOMAS, R.J.
2000-01-01
This document specifies the critical characteristics for Commercial Grade Items (CGI) procured for use in the Plutonium Finishing Plant as required by HNF-PRO-268 and HNF-PRO-1819. These are the minimum specifications that the equipment must meet in order to properly perform its safety function. There may be several manufacturers or models that meet the critical characteristics of any one item
Safety physics inter-comparison of advanced concepts of critical reactors and ADS
International Nuclear Information System (INIS)
Slessarev, I.
2001-01-01
Enhanced safety based on the principle of the natural ''self-defence'' is one of the most desirable features of innovative nuclear systems (critical or sub-critical) regarding both TRU transmutation and ''clean'' energy producer concepts. For the evaluation of the ''self-defence'' domain, the method of the asymptotic reactivity balance has been generalised. The promising option of Hybrids systems (that use a symbiosis of fission and spallation in sub-critical cores) which could benefit the advantages of both Accelerated Driven Systems of the traditional type and regular critical systems, has been advocated. General features of Hybrid dynamics have been presented and analysed. It was demonstrated that an external neutron source of Hybrids can expand the inherent safety potential significantly. This analysis has been applied to assess the safety physics potential of innovative concepts for prospective nuclear power both for energy producers and for transmutation. It has been found, that safety enhancement goal defines a choice of sub-criticality of Hybrids. As for energy producers with Th-fuel cycle, a significant sub-criticality level is required due to a necessity of an improvement of neutronics together with safety enhancement task. (author)
Software reliability for safety-critical applications
International Nuclear Information System (INIS)
Everett, B.; Musa, J.
1994-01-01
In this talk, the authors address the question open-quotes Can Software Reliability Engineering measurement and modeling techniques be applied to safety-critical applications?close quotes Quantitative techniques have long been applied in engineering hardware components of safety-critical applications. The authors have seen a growing acceptance and use of quantitative techniques in engineering software systems but a continuing reluctance in using such techniques in safety-critical applications. The general case posed against using quantitative techniques for software components runs along the following lines: safety-critical applications should be engineered such that catastrophic failures occur less frequently than one in a billion hours of operation; current software measurement/modeling techniques rely on using failure history data collected during testing; one would have to accumulate over a billion operational hours to verify failure rate objectives of about one per billion hours
Reusable libraries for safety-critical Java
DEFF Research Database (Denmark)
Rios Rivas, Juan Ricardo; Schoeberl, Martin
2014-01-01
The large collection of Java class libraries is a main factor of the success of Java. However, these libraries assume that a garbage-collected heap is used. Safety-critical Java uses scope-based memory areas instead of a garbage-collected heap. Therefore, the Java class libraries are problematic...... to use in safety-critical Java. We have identified common programming patterns in the Java class libraries that make them unsuitable for safety-critical Java. We propose ways to improve the libraries to avoid the impact of the identified problematic patterns. We illustrate these changes by implementing...
International Nuclear Information System (INIS)
Naito, Yoshitaka; Koyama, Takashi; Komuro, Yuichi
1986-03-01
Critical enrichment and critical density of homogenous infinite systems, such as U-H 2 O, UO 2 -H 2 O, UO 2 F 2 aqueous solution, UO 2 (NO 3 ) 2 aqueous solution, Pu-H 2 O, PuO 2 -H 2 O, Pu(NO 3 ) 4 aqueous solution and PuO 2 ·UO 2 -H 2 O, were calculated with the criticality safety evaluation computer code system JACS for nuclear criticality safety evaluation on fuel facilities. The computed results were compared with the data described in European and American criticality handbooks and showed good agreement with each other. (author)
American National Standard administrative practices for nuclear criticality safety, ANSI/ANS-8.19
International Nuclear Information System (INIS)
Smith, D.R.; Carson, R.W.
1991-01-01
American National Standard Administrative Practices for Nuclear Criticality Safety, ANSI/ANS-8.19, provides guidance for the administration of an effective program to control the risk of nuclear criticality in operations with fissile material outside reactors. The several sections of the standard address the responsibilities of management, supervisory personnel, and the criticality safety staff, as well as requirements and suggestions for the content of operating procedures, process evaluations, material control procedures, and emergency procedures
Evolvement of nuclear criticality safety programs
International Nuclear Information System (INIS)
Ketzlach, N.
1992-01-01
Nuclear criticality safety (NCS) has developed from a discipline requiring the services of personnel with only a background in reactor physics to that involving reactor physics, process engineering, and design as well as administration of the program to ensure all its requirements are implemented. When Oak Ridge National Laboratory (ORNL) was designed and constructed, the physicists at Los Alamos National Laboratory (LANL) were performing the criticality analyses. A physicist who had no chemical process or engineering experience was brought in from LANL to determine whether the facility would be safe. It was only because of his understanding of the reactor physics principles, scientific intuition, and some luck that the design and construction of the facility led to a safe plant. It took a number of years of experience with facility operations and the dedication of personnel for NCS to reach its present status as a recognized discipline
Nuclear Data Activities in Support of the DOE Nuclear Criticality Safety Program
International Nuclear Information System (INIS)
Westfall, R.M.; McKnight, R.D.
2005-01-01
The DOE Nuclear Criticality Safety Program (NCSP) provides the technical infrastructure maintenance for those technologies applied in the evaluation and performance of safe fissionable-material operations in the DOE complex. These technologies include an Analytical Methods element for neutron transport as well as the development of sensitivity/uncertainty methods, the performance of Critical Experiments, evaluation and qualification of experiments as Benchmarks, and a comprehensive Nuclear Data program coordinated by the NCSP Nuclear Data Advisory Group (NDAG).The NDAG gathers and evaluates differential and integral nuclear data, identifies deficiencies, and recommends priorities on meeting DOE criticality safety needs to the NCSP Criticality Safety Support Group (CSSG). Then the NDAG identifies the required resources and unique capabilities for meeting these needs, not only for performing measurements but also for data evaluation with nuclear model codes as well as for data processing for criticality safety applications. The NDAG coordinates effort with the leadership of the National Nuclear Data Center, the Cross Section Evaluation Working Group (CSEWG), and the Working Party on International Evaluation Cooperation (WPEC) of the OECD/NEA Nuclear Science Committee. The overall objective is to expedite the issuance of new data and methods to the DOE criticality safety user. This paper describes these activities in detail, with examples based upon special studies being performed in support of criticality safety for a variety of DOE operations
A desktop 3D printer in safety-critical Java
DEFF Research Database (Denmark)
Strøm, Tórur Biskopstø; Schoeberl, Martin
2012-01-01
there exist several safety-critical Java framework implementations, there is a lack of safety-critical use cases implemented according to the specification. In this paper we present a 3D printer and its safety-critical Java level 1 implementation as a use case. With basis in the implementation we evaluate......It is desirable to bring Java technology to safety-critical systems. To this end The Open Group has created the safety-critical Java specification, which will allow Java applications, written according to the specification, to be certifiable in accordance with safety-critical standards. Although...
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.
Review of Nuclear Criticality Safety Requirements Implementation for Hanford Tank Farms Facility
International Nuclear Information System (INIS)
DEFIGH PRICE, C.
2000-01-01
In November 1999, the Deputy Secretary of the Department of Energy directed a series of actions to strengthen the Department's ongoing nuclear criticality safety programs. A Review Plan describing lines of inquiry for assessing contractor programs was included. The Office of River Protection completed their assessment of the Tank Farm Contractor program in May 2000. This document supports that assessment by providing a compliance statement for each line of inquiry
Training and qualification program for nuclear criticality safety technical staff. Revision 1
International Nuclear Information System (INIS)
Taylor, R.G.; Worley, C.A.
1997-01-01
A training and qualification program for nuclear criticality safety technical staff personnel has been developed and implemented. All personnel who are to perform nuclear criticality safety technical work are required to participate in the program. The program includes both general nuclear criticality safety and plant specific knowledge components. Advantage can be taken of previous experience for that knowledge which is portable such as performance of computer calculations. Candidates step through a structured process which exposes them to basic background information, general plant information, and plant specific information which they need to safely and competently perform their jobs. Extensive documentation is generated to demonstrate that candidates have met the standards established for qualification
A formal safety analysis for PLC software-based safety critical system using Z
International Nuclear Information System (INIS)
Koh, Jung Soo; Seong, Poong Hyun
1997-01-01
This paper describes a formal safety analysis technique which is demonstrated by performing empirical formal safety analysis with the case study of beamline hutch door Interlock system that is developed by using PLC (Programmable Logic Controller) systems at the Pohang Accelerator Laboratory. In order to perform formed safety analysis, we have built the Z formal specifications representation from user requirement written in ambiguous natural language and target PLC ladder logic, respectively. We have also studied the effective method to express typical PLC timer component by using specific Z formal notation which is supported by temporal history. We present a formal proof technique specifying and verifying that the hazardous states are not introduced into ladder logic in the PLC-based safety critical system
A Profile for Safety Critical Java
DEFF Research Database (Denmark)
Schoeberl, Martin; Søndergaard, Hans; Thomsen, Bent
2007-01-01
We propose a new, minimal specification for real-time Java for safety critical applications. The intention is to provide a profile that supports programming of applications that can be validated against safety critical standards such as DO-178B [15]. The proposed profile is in line with the Java...... specification request JSR-302: Safety Critical Java Technology, which is still under discussion. In contrast to the current direction of the expert group for the JSR-302 we do not subset the rather complex Real-Time Specification for Java (RTSJ). Nevertheless, our profile can be implemented on top of an RTSJ...
Criticality safety research on nuclear fuel cycle facility
Energy Technology Data Exchange (ETDEWEB)
Miyoshi, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
2004-07-01
This paper present d s current status and future program of the criticality safety research on nuclear fuel cycle made by Japan Atomic Energy Research Institute. Experimental research on solution fuel treated in reprocessing plant has been performed using two critical facilities, STACY and TRACY. Fundamental data of static and transient characteristics are accumulated for validation of criticality safety codes. Subcritical measurements are also made for developing a monitoring system for criticality safety. Criticality safety codes system for solution and power system, and evaluation method related to burnup credit are developed. (author)
Patterns for Safety-Critical Java Memory Usage
DEFF Research Database (Denmark)
Rios Rivas, Juan Ricardo; Nilsen, Kelvin; Schoeberl, Martin
2012-01-01
Scoped memories are introduced in real-time Java profiles in order to make object allocation and deallocation time and space predictable. However, explicit scoping requires care from programmers when dealing with temporary objects, passing scope-allocated objects as arguments to methods, and retu......Scoped memories are introduced in real-time Java profiles in order to make object allocation and deallocation time and space predictable. However, explicit scoping requires care from programmers when dealing with temporary objects, passing scope-allocated objects as arguments to methods...... are illustrated by implementations in the safety-critical Java profile....
Nuclear criticality safety in Canada
International Nuclear Information System (INIS)
Shultz, K.R.
1980-04-01
The approach taken to nuclear criticality safety in Canada has been influenced by the historical development of participants. The roles played by governmental agencies and private industry since the Atomic Energy Control Act was passed into Canadian Law in 1946 are outlined to set the scene for the current situation and directions that may be taken in the future. Nuclear criticality safety puts emphasis on the control of materials called special fissionable material in Canada. A brief account is given of the historical development and philosophy underlying the existing regulations governing special fissionable material. Subsequent events have led to a change in emphasis in the regulatory process that has not yet been fully integrated into Canadian legislation and regulations. Current efforts towards further development of regulations governing the practice of nuclear criticality safety are described. (auth)
Safety physics inter-comparison of advanced concepts of critical reactors and ADS
Energy Technology Data Exchange (ETDEWEB)
Slessarev, I. [CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d' Etudes des Reacteurs
2001-07-01
Enhanced safety based on the principle of the natural ''self-defence'' is one of the most desirable features of innovative nuclear systems (critical or sub-critical) regarding both TRU transmutation and ''clean'' energy producer concepts. For the evaluation of the ''self-defence'' domain, the method of the asymptotic reactivity balance has been generalised. The promising option of Hybrids systems (that use a symbiosis of fission and spallation in sub-critical cores) which could benefit the advantages of both Accelerated Driven Systems of the traditional type and regular critical systems, has been advocated. General features of Hybrid dynamics have been presented and analysed. It was demonstrated that an external neutron source of Hybrids can expand the inherent safety potential significantly. This analysis has been applied to assess the safety physics potential of innovative concepts for prospective nuclear power both for energy producers and for transmutation. It has been found, that safety enhancement goal defines a choice of sub-criticality of Hybrids. As for energy producers with Th-fuel cycle, a significant sub-criticality level is required due to a necessity of an improvement of neutronics together with safety enhancement task. (author)
2010-09-29
The Food and Drug Administration (FDA) is amending its regulations governing safety reporting requirements for human drug and biological products subject to an investigational new drug application (IND). The final rule codifies the agency's expectations for timely review, evaluation, and submission of relevant and useful safety information and implements internationally harmonized definitions and reporting standards. The revisions will improve the utility of IND safety reports, reduce the number of reports that do not contribute in a meaningful way to the developing safety profile of the drug, expedite FDA's review of critical safety information, better protect human subjects enrolled in clinical trials, subject bioavailability and bioequivalence studies to safety reporting requirements, promote a consistent approach to safety reporting internationally, and enable the agency to better protect and promote public health.
Energy Technology Data Exchange (ETDEWEB)
NONE
1998-09-01
This Department of Energy (DOE) is approved for use by all components of DOE. It contains guidelines that should be followed when preparing Criticality Safety Evaluations that will be used to demonstrate the safety of operations performed at DOE Non-Reactor Nuclear Facilities. Adherence with these guidelines will provide consistency and uniformity in Criticality Safety Evaluations (CSEs) across the complex and will document compliance with DOE Order 5480.24 requirements as they pertain to CSEs.
International Nuclear Information System (INIS)
1998-09-01
This Department of Energy (DOE) is approved for use by all components of DOE. It contains guidelines that should be followed when preparing Criticality Safety Evaluations that will be used to demonstrate the safety of operations performed at DOE Non-Reactor Nuclear Facilities. Adherence with these guidelines will provide consistency and uniformity in Criticality Safety Evaluations (CSEs) across the complex and will document compliance with DOE Order 5480.24 requirements as they pertain to CSEs
Nuclear criticality safety: 3-day training course
International Nuclear Information System (INIS)
Schlesser, J.A.
1993-06-01
The open-quotes 3-Day Training Courseclose quotes is an intensive course in criticality safety consisting of lectures and laboratory sessions, including active student participation in actual critical experiments, a visit to a plutonium processing facility, and in-depth discussions on safety philosophy. The program is directed toward personnel who currently have criticality safety responsibilities in the capacity of supervisory staff and/or line management. This compilation of notes is presented as a source reference for the criticality safety course. It represents the contributions of many people, particularly Tom McLaughlin, the course's primary instructor. It should be noted that when chapters were extracted, an attempt was made to maintain footnotes and references as originally written. Photographs and illustrations are numbered sequentially
Criticality safety issues in the disposition of BN-350 spent fuel
International Nuclear Information System (INIS)
Schaefer, R. W.; Klann, R. T.; Koltyshev, S. M.; Krechetov, S.
2000-01-01
A criticality safety analysis has been performed as part of the BN-350 spent fuel disposition project being conducted jointly by the DOE and Kazakhstan. The Kazakhstan regulations are reasonably consistent with those of the DOE. The high enrichment and severe undermoderation of this fast reactor fuel has significant criticality safety consequences. A detailed modeling approach was used that showed some configurations to be safe that otherwise would be rejected. Reasonable requirements for design and operations were needed, and with them, all operations were found to be safe
Status of criticality safety research at NUCEF
Energy Technology Data Exchange (ETDEWEB)
Nakajima, Ken [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-03-01
Two critical facilities, named STACY (Static Experiment Critical Facility) and TRACY (Transient Experiment Critical Facility), at the Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF) started their hot operations in 1995. Since then, basic experimental data for criticality safety research have been accumulated using STACY, and supercritical experiments for the study of criticality accident in a reprocessing plant have been performed using TRACY. In this paper, the outline of those critical facilities and the main results of TRACY experiments are presented. (author)
Proceedings of the Nuclear Criticality Technology Safety Workshop
Energy Technology Data Exchange (ETDEWEB)
Rene G. Sanchez
1998-04-01
This document contains summaries of most of the papers presented at the 1995 Nuclear Criticality Technology Safety Project (NCTSP) meeting, which was held May 16 and 17 at San Diego, Ca. The meeting was broken up into seven sessions, which covered the following topics: (1) Criticality Safety of Project Sapphire; (2) Relevant Experiments For Criticality Safety; (3) Interactions with the Former Soviet Union; (4) Misapplications and Limitations of Monte Carlo Methods Directed Toward Criticality Safety Analyses; (5) Monte Carlo Vulnerabilities of Execution and Interpretation; (6) Monte Carlo Vulnerabilities of Representation; and (7) Benchmark Comparisons.
Program of nuclear criticality safety experiment at JAERI
International Nuclear Information System (INIS)
Kobayashi, Iwao; Tachimori, Shoichi; Takeshita, Isao; Suzaki, Takenori; Ohnishi, Nobuaki
1983-11-01
JAERI is promoting the nuclear criticality safety research program, in which a new facility for criticality safety experiments (Criticality Safety Experimental Facility : CSEF) is to be built for the experiments with solution fuel. One of the experimental researches is to measure, collect and evaluate the experimental data needed for evaluation of criticality safety of the nuclear fuel cycle facilities. Another research area is a study of the phenomena themselves which are incidental to postulated critical accidents. Investigation of the scale and characteristics of the influences caused by the accident is also included in this research. The result of the conceptual design of CSEF is summarized in this report. (author)
Qualification of safety-critical software for digital reactor safety system in nuclear power plants
International Nuclear Information System (INIS)
Kwon, Kee-Choon; Park, Gee-Yong; Kim, Jang-Yeol; Lee, Jang-Soo
2013-01-01
This paper describes the software qualification activities for the safety-critical software of the digital reactor safety system in nuclear power plants. The main activities of the software qualification processes are the preparation of software planning documentations, verification and validation (V and V) of the software requirements specifications (SRS), software design specifications (SDS) and codes, and the testing of the integrated software and integrated system. Moreover, the software safety analysis and software configuration management are involved in the software qualification processes. The V and V procedure for SRS and SDS contains a technical evaluation, licensing suitability evaluation, inspection and traceability analysis, formal verification, software safety analysis, and an evaluation of the software configuration management. The V and V processes for the code are a traceability analysis, source code inspection, test case and test procedure generation. Testing is the major V and V activity of the software integration and system integration phases. The software safety analysis employs a hazard operability method and software fault tree analysis. The software configuration management in each software life cycle is performed by the use of a nuclear software configuration management tool. Through these activities, we can achieve the functionality, performance, reliability, and safety that are the major V and V objectives of the safety-critical software in nuclear power plants. (author)
The International Criticality Safety Benchmark Evaluation Project
International Nuclear Information System (INIS)
Briggs, B. J.; Dean, V. F.; Pesic, M. P.
2001-01-01
In order to properly manage the risk of a nuclear criticality accident, it is important to establish the conditions for which such an accident becomes possible for any activity involving fissile material. Only when this information is known is it possible to establish the likelihood of actually achieving such conditions. It is therefore important that criticality safety analysts have confidence in the accuracy of their calculations. Confidence in analytical results can only be gained through comparison of those results with experimental data. The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in October of 1992 by the US Department of Energy. The project was managed through the Idaho National Engineering and Environmental Laboratory (INEEL), but involved nationally known criticality safety experts from Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Savannah River Technology Center, Oak Ridge National Laboratory and the Y-12 Plant, Hanford, Argonne National Laboratory, and the Rocky Flats Plant. An International Criticality Safety Data Exchange component was added to the project during 1994 and the project became what is currently known as the International Criticality Safety Benchmark Evaluation Project (ICSBEP). Representatives from the United Kingdom, France, Japan, the Russian Federation, Hungary, Kazakhstan, Korea, Slovenia, Yugoslavia, Spain, and Israel are now participating on the project In December of 1994, the ICSBEP became an official activity of the Organization for Economic Cooperation and Development - Nuclear Energy Agency's (OECD-NEA) Nuclear Science Committee. The United States currently remains the lead country, providing most of the administrative support. The purpose of the ICSBEP is to: (1) identify and evaluate a comprehensive set of critical benchmark data; (2) verify the data, to the extent possible, by reviewing original and subsequently revised documentation, and by talking with the
Criticality safety assessment of FBTR fuel sub-assemblies using WIMS cross section set
International Nuclear Information System (INIS)
Gupta, H.C.; Chakraborty, B.
2002-01-01
Full text: FBTR's irradiated fuel sub-assemblies (FSAs) are sent to RML at Indira Gandhi Centre for Atomic Research for post irradiation examination. The FSAs are cut open and the fuel pins are separated for examination in the hot cells. It was required to evaluate the criticality safety in handling the FSAs in the hot cells. Criticality safety studies for handling two as well as three irradiated FSAs in the hot cells under dry conditions were carried out by the Safety Group at IGCAR, Kalpakkam. Monte Carlo code KENO (Version Va) which uses 16-group Hansen-Roach cross-section set was used for the calculations. Subsequently, during the safety review of the proposition by the Safety Review Committee (SARCOP) of AERB, it was stipulated to carry out the criticality safety studies under flooded condition also. We carried out the criticality safety studies for these fuel sub assemblies in different configurations under dry (buried in concrete) as well as wet condition (flooded with light water) using Monte Carlo codes MONALI (developed at BARC) and KENO4 using WlMS-69 group cross section set. Results of our analyses under various conditions are presented in this paper
Architecture Level Safety Analyses for Safety-Critical Systems
Directory of Open Access Journals (Sweden)
K. S. Kushal
2017-01-01
Full Text Available The dependency of complex embedded Safety-Critical Systems across Avionics and Aerospace domains on their underlying software and hardware components has gradually increased with progression in time. Such application domain systems are developed based on a complex integrated architecture, which is modular in nature. Engineering practices assured with system safety standards to manage the failure, faulty, and unsafe operational conditions are very much necessary. System safety analyses involve the analysis of complex software architecture of the system, a major aspect in leading to fatal consequences in the behaviour of Safety-Critical Systems, and provide high reliability and dependability factors during their development. In this paper, we propose an architecture fault modeling and the safety analyses approach that will aid in identifying and eliminating the design flaws. The formal foundations of SAE Architecture Analysis & Design Language (AADL augmented with the Error Model Annex (EMV are discussed. The fault propagation, failure behaviour, and the composite behaviour of the design flaws/failures are considered for architecture safety analysis. The illustration of the proposed approach is validated by implementing the Speed Control Unit of Power-Boat Autopilot (PBA system. The Error Model Annex (EMV is guided with the pattern of consideration and inclusion of probable failure scenarios and propagation of fault conditions in the Speed Control Unit of Power-Boat Autopilot (PBA. This helps in validating the system architecture with the detection of the error event in the model and its impact in the operational environment. This also provides an insight of the certification impact that these exceptional conditions pose at various criticality levels and design assurance levels and its implications in verifying and validating the designs.
Plant safety review from mass criticality accident
International Nuclear Information System (INIS)
Susanto, B.G.
2000-01-01
The review has been done to understand the resent status of the plant in facing postulated mass criticality accident. From the design concept of the plant all the components in the system including functional groups have been designed based on favorable mass/geometry safety principle. The criticality safety for each component is guaranteed because all the dimensions relevant to criticality of the components are smaller than dimensions of 'favorable mass/geometry'. The procedures covering all aspects affecting quality including the safety related are developed and adhered to at all times. Staff are indoctrinated periodically in short training session to warn the important of the safety in process of production. The plant is fully equipped with 6 (six) criticality detectors in strategic places to alert employees whenever the postulated mass criticality accident occur. In the event of Nuclear Emergency Preparedness, PT BATAN TEKNOLOGI has also proposed the organization structure how promptly to report the crisis to Nuclear Energy Control Board (BAPETEN) Indonesia. (author)
Nuclear Criticality Safety Handbook, Version 2. English translation
International Nuclear Information System (INIS)
2001-08-01
The Nuclear Criticality Safety Handbook, Version 2 essentially includes the description of the Supplement Report to the Nuclear Criticality Safety Handbook, released in 1995, into the first version of the Nuclear Criticality Safety Handbook, published in 1988. The following two points are new: (1) exemplifying safety margins related to modeled dissolution and extraction processes, (2) describing evaluation methods and alarm system for criticality accidents. Revision has been made based on previous studies for the chapter that treats modeling the fuel system: e.g., the fuel grain size that the system can be regarded as homogeneous, non-uniformity effect of fuel solution, an burnup credit. This revision has solved the inconsistencies found in the first version between the evaluation of errors found in JACS code system and the criticality condition data that were calculated based on the evaluation. This report is an English translation of the Nuclear Criticality Safety Handbook, Version 2, originally published in Japanese as JAERI 1340 in 1999. (author)
Realism in nuclear criticality safety
International Nuclear Information System (INIS)
McLaughlin, T. P.
2009-01-01
Commercial nuclear power plant operation and regulation have made remarkable progress since the Three Mile Island Accident. This is attributed largely to a heavy dose of introspection and self-regulation by the industry and to a significant infusion of risk-informed and performance-based regulation by the Nuclear Regulatory Commission. This truly represents reality in action both by the plant operators and the regulators. On the other hand, the implementation of nuclear criticality safety in ex-reactor operations involving significant quantities of fissile material has not progressed, but, tragically, it has regressed. Not only is the practice of the discipline in excess of a factor of ten more expensive than decades ago; the trend continues. This unfortunate reality is attributed to a lack of coordination within the industry (as contrasted to what occurred in the reactor operations sector), and to a lack of implementation of risk-informed and performance-based regulation by the NRC While the criticality safety discipline is orders of magnitude smaller than the reactor safety discipline, both operators and regulators must learn from the progress made in reactor safety and apply it to the former to reduce the waste, inefficiency and potentially increased accident risks associated with current practices. Only when these changes are made will there be progress made toward putting realism back into nuclear criticality safety. (authors)
Introduction to 'International Handbook of Criticality Safety Benchmark Experiments'
International Nuclear Information System (INIS)
Komuro, Yuichi
1998-01-01
The Criticality Safety Benchmark Evaluation Project (CSBEP) was initiated in 1992 by the United States Department of Energy. The project quickly became an international effort as scientists from other interested countries became involved. The International Criticality Safety Benchmark Evaluation Project (ICSBEP) is now an official activity of the Organization for Economic Cooperation and Development-Nuclear Energy Agency (OECD-NEA). 'International Handbook of Criticality Safety Benchmark Experiments' was prepared and is updated year by year by the working group of the project. This handbook contains criticality safety benchmark specifications that have been derived from experiments that were performed at various nuclear critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculation techniques used. The author briefly introduces the informative handbook and would like to encourage Japanese engineers who are in charge of nuclear criticality safety to use the handbook. (author)
Minimum qualifications for nuclear criticality safety professionals
International Nuclear Information System (INIS)
Ketzlach, N.
1990-01-01
A Nuclear Criticality Technology and Safety Training Committee has been established within the U.S. Department of Energy (DOE) Nuclear Criticality Safety and Technology Project to review and, if necessary, develop standards for the training of personnel involved in nuclear criticality safety (NCS). The committee is exploring the need for developing a standard or other mechanism for establishing minimum qualifications for NCS professionals. The development of standards and regulatory guides for nuclear power plant personnel may serve as a guide in developing the minimum qualifications for NCS professionals
International Nuclear Information System (INIS)
Koo, Seo Ryong; Seong, Poong Hyun; Yoo, Junbeom; Cha, Sung Deok; Yoo, Yeong Jae
2005-01-01
A thorough requirements analysis is indispensable for developing and implementing safety-critical software systems such as nuclear power plant (NPP) software systems because a single error in the requirements can generate serious software faults. However, it is very difficult to completely analyze system requirements. In this paper, an effective technique for the software requirements analysis is suggested. For requirements verification and validation (V and V) tasks, our technique uses software inspection, requirement traceability, and formal specification with structural decomposition. Software inspection and requirements traceability analysis are widely considered the most effective software V and V methods. Although formal methods are also considered an effective V and V activity, they are difficult to use properly in the nuclear fields as well as in other fields because of their mathematical nature. In this work, we propose an integrated environment (IE) approach for requirements, which is an integrated approach that enables easy inspection by combining requirement traceability and effective use of a formal method. The paper also introduces computer-aided tools for supporting IE approach for requirements. Called the nuclear software inspection support and requirements traceability (NuSISRT), the tool incorporates software inspection, requirement traceability, and formal specification capabilities. We designed the NuSISRT to partially automate software inspection and analysis of requirement traceability. In addition, for the formal specification and analysis, we used the formal requirements specification and analysis tool for nuclear engineering (NuSRS)
International Nuclear Information System (INIS)
Rathbun, R.
1993-01-01
Review of NMP-NCS-930087, open-quotes Nuclear Criticality Safety Evaluation 93-04 Enriched Uranium Receipt (U), July 30, 1993, close quotes was requested of SRTC (Savannah River Technology Center) Applied Physics Group. The NCSE is a criticality assessment to determine the mass limit for Engineered Low Level Trench (ELLT) waste uranium burial. The intent is to bury uranium in pits that would be separated by a specified amount of undisturbed soil. The scope of the technical review, documented in this report, consisted of (1) an independent check of the methods and models employed, (2) independent HRXN/KENO-V.a calculations of alternate configurations, (3) application of ANSI/ANS 8.1, and (4) verification of WSRC Nuclear Criticality Safety Manual procedures. The NCSE under review concludes that a 500 gram limit per burial position is acceptable to ensure the burial site remains in a critically safe configuration for all normal and single credible abnormal conditions. This reviewer agrees with that conclusion
Safety of nuclear power plants: Operation. Safety requirements
International Nuclear Information System (INIS)
2004-01-01
The safety of a nuclear power plant is ensured by means of its proper siting, design, construction and commissioning, followed by the proper management and operation of the plant. In a later phase, proper decommissioning is required. This Safety Requirements publication supersedes the Code on the Safety of Nuclear Power Plants: Operation, which was issued in 1988 as Safety Series No. 50-C-O (Rev. 1). The purpose of this revision was: to restructure Safety Series No. 50-C-O (Rev. 1) in the light of the basic objectives, concepts and principles in the Safety Fundamentals publication The Safety of Nuclear Installations. To be consistent with the requirements of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources. And to reflect current practice and new concepts and technical developments. Guidance on fulfillment of these Safety Requirements may be found in the appropriate Safety Guides relating to plant operation. The objective of this publication is to establish the requirements which, in the light of experience and the present state of technology, must be satisfied to ensure the safe operation of nuclear power plants. These requirements are governed by the basic objectives, concepts and principles that are presented in the Safety Fundamentals publication The Safety of Nuclear Installations. This publication deals with matters specific to the safe operation of land based stationary thermal neutron nuclear power plants, and also covers their commissioning and subsequent decommissioning
Safety of nuclear power plants: Operation. Safety requirements
International Nuclear Information System (INIS)
2003-01-01
The safety of a nuclear power plant is ensured by means of its proper siting, design, construction and commissioning, followed by the proper management and operation of the plant. In a later phase, proper decommissioning is required. This Safety Requirements publication supersedes the Code on the Safety of Nuclear Power Plants: Operation, which was issued in 1988 as Safety Series No. 50-C-O (Rev. 1). The purpose of this revision was: to restructure Safety Series No. 50-C-O (Rev. 1) in the light of the basic objectives, concepts and principles in the Safety Fundamentals publication The Safety of Nuclear Installations. To be consistent with the requirements of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources. And to reflect current practice and new concepts and technical developments. Guidance on fulfillment of these Safety Requirements may be found in the appropriate Safety Guides relating to plant operation. The objective of this publication is to establish the requirements which, in the light of experience and the present state of technology, must be satisfied to ensure the safe operation of nuclear power plants. These requirements are governed by the basic objectives, concepts and principles that are presented in the Safety Fundamentals publication The Safety of Nuclear Installations. This publication deals with matters specific to the safe operation of land based stationary thermal neutron nuclear power plants, and also covers their commissioning and subsequent decommissioning
Safety of nuclear power plants: Operation. Safety requirements
International Nuclear Information System (INIS)
2000-01-01
The safety of a nuclear power plant is ensured by means of its proper siting, design, construction and commissioning, followed by the proper management and operation of the plant. In a later phase, proper decommissioning is required. This Safety Requirements publication supersedes the Code on the Safety of Nuclear Power Plants: Operation, which was issued in 1988 as Safety Series No. 50-C-O (Rev. 1). The purpose of this revision was: to restructure Safety Series No. 50-C-O (Rev. 1) in the light of the basic objectives, concepts and principles in the Safety Fundamentals publication The Safety of Nuclear Installations; to be consistent with the requirements of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources; and to reflect current practice and new concepts and technical developments. Guidance on fulfillment of these Safety Requirements may be found in the appropriate Safety Guides relating to plant operation. The objective of this publication is to establish the requirements which, in the light of experience and the present state of technology, must be satisfied to ensure the safe operation of nuclear power plants. These requirements are governed by the basic objectives, concepts and principles that are presented in the Safety Fundamentals publication The Safety of Nuclear Installations. This publication deals with matters specific to the safe operation of land based stationary thermal neutron nuclear power plants, and also covers their commissioning and subsequent decommissioning
Nuclear Criticality Safety Data Book
Energy Technology Data Exchange (ETDEWEB)
Hollenbach, D. F. [Y-12 National Security Complex, Oak Ridge, TN (United States)
2016-11-14
The objective of this document is to support the revision of criticality safety process studies (CSPSs) for the Uranium Processing Facility (UPF) at the Y-12 National Security Complex (Y-12). This design analysis and calculation (DAC) document contains development and justification for generic inputs typically used in Nuclear Criticality Safety (NCS) DACs to model both normal and abnormal conditions of processes at UPF to support CSPSs. This will provide consistency between NCS DACs and efficiency in preparation and review of DACs, as frequently used data are provided in one reference source.
Nuclear Criticality Safety Data Book
International Nuclear Information System (INIS)
Hollenbach, D. F.
2016-01-01
The objective of this document is to support the revision of criticality safety process studies (CSPSs) for the Uranium Processing Facility (UPF) at the Y-12 National Security Complex (Y-12). This design analysis and calculation (DAC) document contains development and justification for generic inputs typically used in Nuclear Criticality Safety (NCS) DACs to model both normal and abnormal conditions of processes at UPF to support CSPSs. This will provide consistency between NCS DACs and efficiency in preparation and review of DACs, as frequently used data are provided in one reference source.
Exemption, exception and other criteria for transport criticality safety
International Nuclear Information System (INIS)
Mennerdahl, D.
2004-01-01
Many strange concepts, requirements and specifications related to criticality safety are present in the Regulations. Some earlier problems have been corrected but, going back to 1961 and the first edition of the Regulations, it seems as many changes have been to the worse. Fissile material was defined correctly as a material that could consist of or contain fissile nuclides. Materials consisting of pure fissile nuclides don't exist but are important in package designs. 238 Pu was included as a fissile nuclide only as an emergency, because there was no alternative, but this caused some people to think that all nuclides supporting criticality are fissile. Neutron interaction between different (non-identical) packages had to be evaluated, making the transport index or allowable number of packages a credible safety control. That is not true anymore. The 15 gram exception limit for fissile nuclides was combined with a transport mode limit, similar to but more restrictive than the current consignment limit. The confinement system was introduced to help with formulation of a single requirement for safety of the containment system but is becoming something very different. Controls before the first use of a packaging have become controls of the first use of a package, supporting multiple shipments of the same package. The lack of exemption limits for fissile material essentially makes all radioactive materials fissile (all radioactive material contains some fissile atoms). Radioactive material seems to be defined without consideration of the criticality hazard of the material. LSA materials are defined with consideration of criticality, but only relates to quantities in fissile exceptions when other properties can be equally or more important. In July 2004, a number of proposals to IAEA have been submitted by Sweden to improve and expand the criticality safety control of the Regulations. Essential is the introduction of the fissionable nuclide and material concepts in
Exemption, exception and other criteria for transport criticality safety
Energy Technology Data Exchange (ETDEWEB)
Mennerdahl, D. [E Mennerdahl Systems, Taeby (Sweden)
2004-07-01
Many strange concepts, requirements and specifications related to criticality safety are present in the Regulations. Some earlier problems have been corrected but, going back to 1961 and the first edition of the Regulations, it seems as many changes have been to the worse. Fissile material was defined correctly as a material that could consist of or contain fissile nuclides. Materials consisting of pure fissile nuclides don't exist but are important in package designs. {sup 238}Pu was included as a fissile nuclide only as an emergency, because there was no alternative, but this caused some people to think that all nuclides supporting criticality are fissile. Neutron interaction between different (non-identical) packages had to be evaluated, making the transport index or allowable number of packages a credible safety control. That is not true anymore. The 15 gram exception limit for fissile nuclides was combined with a transport mode limit, similar to but more restrictive than the current consignment limit. The confinement system was introduced to help with formulation of a single requirement for safety of the containment system but is becoming something very different. Controls before the first use of a packaging have become controls of the first use of a package, supporting multiple shipments of the same package. The lack of exemption limits for fissile material essentially makes all radioactive materials fissile (all radioactive material contains some fissile atoms). Radioactive material seems to be defined without consideration of the criticality hazard of the material. LSA materials are defined with consideration of criticality, but only relates to quantities in fissile exceptions when other properties can be equally or more important. In July 2004, a number of proposals to IAEA have been submitted by Sweden to improve and expand the criticality safety control of the Regulations. Essential is the introduction of the fissionable nuclide and material
Researches on nuclear criticality safety evaluation
Energy Technology Data Exchange (ETDEWEB)
Okuno, Hiroshi; Suyama, Kenya; Nomura, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
2003-10-01
For criticality safety evaluation of burnup fuel, the general-purpose burnup calculation code, SWAT, was revised, and its precision was confirmed through comparison with other results from OECD/NEA's burnup credit benchmarks. Effect by replacing the evaluated nuclear data from JENDL-3.2 to ENDF/B-VI and JEF-2.2 was also studied. Correction factors were derived for conservative evaluation of nuclide concentrations obtained with the simplified burnup code ORIGEN2.1. The critical masses of curium were calculated and evaluated for nuclear criticality safety management of minor actinides. (author)
Researches on nuclear criticality safety evaluation
International Nuclear Information System (INIS)
Okuno, Hiroshi; Suyama, Kenya; Nomura, Yasushi
2003-01-01
For criticality safety evaluation of burnup fuel, the general-purpose burnup calculation code, SWAT, was revised, and its precision was confirmed through comparison with other results from OECD/NEA's burnup credit benchmarks. Effect by replacing the evaluated nuclear data from JENDL-3.2 to ENDF/B-VI and JEF-2.2 was also studied. Correction factors were derived for conservative evaluation of nuclide concentrations obtained with the simplified burnup code ORIGEN2.1. The critical masses of curium were calculated and evaluated for nuclear criticality safety management of minor actinides. (author)
Economics of the specification 6M safety re-evaluation and regulatory requirements
International Nuclear Information System (INIS)
Hopper, C.M.
1985-01-01
The objective of this work was to examine the potential economic impact of the DOT Specification 6M criticality safety re-evaluation and regulatory requirements. The examination was based upon comparative analyses of current authorized fissile material load limits for the 6M, current Federal regulations (and interpretations) limiting the contents of Type B fissile material packages, limiting aggregates of fissile material packages, and recent proposed fissile material mass limits derived from specialized criticality safety analyses of the 6M package. The work examines influences on cost in transportation, handling, and storage of fissile materials. Depending upon facility throughput requirements (and assumed incremental costs of fissile material packaging, storage, and transport), operating, facility storage capacity, and transportation costs can be reduced significantly. As an example of the pricing algorithm application based upon reasonable cost influences, the magnitude of the first year cost reductions could extend beyond four times the cost of the packaging nuclear criticality safety re-evaluation. 1 tab
Safety of nuclear power plants: Design. Safety requirements
International Nuclear Information System (INIS)
2000-01-01
The present publication supersedes the Code on the Safety of Nuclear Power Plants: Design (Safety Series No. 50-C-D (Rev. 1), issued in 1988). It takes account of developments relating to the safety of nuclear power plants since the Code on Design was last revised. These developments include the issuing of the Safety Fundamentals publication, The Safety of Nuclear Installations, and the present revision of various safety standards and other publications relating to safety. Requirements for nuclear safety are intended to ensure adequate protection of site personnel, the public and the environment from the effects of ionizing radiation arising from nuclear power plants. It is recognized that technology and scientific knowledge advance, and nuclear safety and what is considered adequate protection are not static entities. Safety requirements change with these developments and this publication reflects the present consensus. This Safety Requirements publication takes account of the developments in safety requirements by, for example, including the consideration of severe accidents in the design process. Other topics that have been given more detailed attention include management of safety, design management, plant ageing and wearing out effects, computer based safety systems, external and internal hazards, human factors, feedback of operational experience, and safety assessment and verification. This publication establishes safety requirements that define the elements necessary to ensure nuclear safety. These requirements are applicable to safety functions and the associated structures, systems and components, as well as to procedures important to safety in nuclear power plants. It is expected that this publication will be used primarily for land based stationary nuclear power plants with water cooled reactors designed for electricity generation or for other heat production applications (such as district heating or desalination). It is recognized that in the case of
Safety of nuclear power plants: Design. Safety requirements
International Nuclear Information System (INIS)
2004-01-01
The present publication supersedes the Code on the Safety of Nuclear Power Plants: Design (Safety Series No. 50-C-D (Rev. 1), issued in 1988). It takes account of developments relating to the safety of nuclear power plants since the Code on Design was last revised. These developments include the issuing of the Safety Fundamentals publication, The Safety of Nuclear Installations, and the present revision of various safety standards and other publications relating to safety. Requirements for nuclear safety are intended to ensure adequate protection of site personnel, the public and the environment from the effects of ionizing radiation arising from nuclear power plants. It is recognized that technology and scientific knowledge advance, and nuclear safety and what is considered adequate protection are not static entities. Safety requirements change with these developments and this publication reflects the present consensus. This Safety Requirements publication takes account of the developments in safety requirements by, for example, including the consideration of severe accidents in the design process. Other topics that have been given more detailed attention include management of safety, design management, plant ageing and wearing out effects, computer based safety systems, external and internal hazards, human factors, feedback of operational experience, and safety assessment and verification. This publication establishes safety requirements that define the elements necessary to ensure nuclear safety. These requirements are applicable to safety functions and the associated structures, systems and components, as well as to procedures important to safety in nuclear power plants. It is expected that this publication will be used primarily for land based stationary nuclear power plants with water cooled reactors designed for electricity generation or for other heat production applications (such as district heating or desalination). It is recognized that in the case of
Criticality Safety Evaluation of Hanford Tank Farms Facility
Energy Technology Data Exchange (ETDEWEB)
WEISS, E.V.
2000-12-15
Data and calculations from previous criticality safety evaluations and analyses were used to evaluate criticality safety for the entire Tank Farms facility to support the continued waste storage mission. This criticality safety evaluation concludes that a criticality accident at the Tank Farms facility is an incredible event due to the existing form (chemistry) and distribution (neutron absorbers) of tank waste. Limits and controls for receipt of waste from other facilities and maintenance of tank waste condition are set forth to maintain the margin subcriticality in tank waste.
Criticality Safety Evaluation of Hanford Tank Farms Facility
International Nuclear Information System (INIS)
WEISS, E.V.
2000-01-01
Data and calculations from previous criticality safety evaluations and analyses were used to evaluate criticality safety for the entire Tank Farms facility to support the continued waste storage mission. This criticality safety evaluation concludes that a criticality accident at the Tank Farms facility is an incredible event due to the existing form (chemistry) and distribution (neutron absorbers) of tank waste. Limits and controls for receipt of waste from other facilities and maintenance of tank waste condition are set forth to maintain the margin subcriticality in tank waste
Cultural safety and the challenges of translating critically oriented knowledge in practice.
Browne, Annette J; Varcoe, Colleen; Smye, Victoria; Reimer-Kirkham, Sheryl; Lynam, M Judith; Wong, Sabrina
2009-07-01
Cultural safety is a relatively new concept that has emerged in the New Zealand nursing context and is being taken up in various ways in Canadian health care discourses. Our research team has been exploring the relevance of cultural safety in the Canadian context, most recently in relation to a knowledge-translation study conducted with nurses practising in a large tertiary hospital. We were drawn to using cultural safety because we conceptualized it as being compatible with critical theoretical perspectives that foster a focus on power imbalances and inequitable social relationships in health care; the interrelated problems of culturalism and racialization; and a commitment to social justice as central to the social mandate of nursing. Engaging in this knowledge-translation study has provided new perspectives on the complexities, ambiguities and tensions that need to be considered when using the concept of cultural safety to draw attention to racialization, culturalism, and health and health care inequities. The philosophic analysis discussed in this paper represents an epistemological grounding for the concept of cultural safety that links directly to particular moral ends with social justice implications. Although cultural safety is a concept that we have firmly positioned within the paradigm of critical inquiry, ambiguities associated with the notions of 'culture', 'safety', and 'cultural safety' need to be anticipated and addressed if they are to be effectively used to draw attention to critical social justice issues in practice settings. Using cultural safety in practice settings to draw attention to and prompt critical reflection on politicized knowledge, therefore, brings an added layer of complexity. To address these complexities, we propose that what may be required to effectively use cultural safety in the knowledge-translation process is a 'social justice curriculum for practice' that would foster a philosophical stance of critical inquiry at both the
Spent fuel storage criticality safety
Energy Technology Data Exchange (ETDEWEB)
Amin, E M; Elmessiry, A M [National center of nuclear safety and radiation control atomic energy authority, (Egypt)
1995-10-01
The safety aspects of the spent fuel storage pool of the Egyptian test and research reactor one (ET-R R-1) has to be assessed as part of a general overall safety evaluation to be included in a safety analysis report (SAR) for this reactor. The present work treats the criticality safety of the spent fuel storage pool. Conservative calculations based on using fresh fuel has been performed, as well as less conservative using burned fuel. The calculations include cross library generation for burned and fresh fuel for the ET-R R-1 fuel type. The WIMS-D 4 code has been used in library generation and burn up calculation the critically calculations are performed using the one dimensional transport code (ANISN) and the two dimensional diffusion code (DIXY2). The possibility of increasing the storage efficiency either by insertion of absorber sheets of soluble boron salts or by reduction of fuel rod separation has been studied. 8 figs., 2 tabs.
Spent fuel storage criticality safety
International Nuclear Information System (INIS)
Amin, E.M.; Elmessiry, A.M.
1995-01-01
The safety aspects of the spent fuel storage pool of the Egyptian test and research reactor one (ET-R R-1) has to be assessed as part of a general overall safety evaluation to be included in a safety analysis report (SAR) for this reactor. The present work treats the criticality safety of the spent fuel storage pool. Conservative calculations based on using fresh fuel has been performed, as well as less conservative using burned fuel. The calculations include cross library generation for burned and fresh fuel for the ET-R R-1 fuel type. The WIMS-D 4 code has been used in library generation and burn up calculation the critically calculations are performed using the one dimensional transport code (ANISN) and the two dimensional diffusion code (DIXY2). The possibility of increasing the storage efficiency either by insertion of absorber sheets of soluble boron salts or by reduction of fuel rod separation has been studied. 8 figs., 2 tabs
A Web-Based Nuclear Criticality Safety Bibliographic Database
International Nuclear Information System (INIS)
Koponen, B L; Huang, S
2007-01-01
A bibliographic criticality safety database of over 13,000 records is available on the Internet as part of the U.S. Department of Energy's (DOE) Nuclear Criticality Safety Program (NCSP) website. This database is easy to access via the Internet and gets substantial daily usage. This database and other criticality safety resources are available at ncsp.llnl.gov. The web database has evolved from more than thirty years of effort at Lawrence Livermore National Laboratory (LLNL), beginning with compilations of critical experiment reports and American Nuclear Society Transactions
K-effective as a measure of criticality safety
International Nuclear Information System (INIS)
Venner, J.; Haley, R.M.; Bowden, R.L.
2003-01-01
This paper considers the relation between the neutron multiplication of a system, k-effective, and critical parameters. It aims to investigate whether k-effective is always the most appropriate measure of safety. For simple systems handbook data can be effectively utilized, applying a safety factor to critical masses. In such situations, the criticality safety margin is readily apparent. However, more complex systems may use the calculated value of neutron multiplication to assess the criticality safety of the system under investigation. A problem arises because there is no exact consistency between k-effective and the physical margin of subcriticality, in terms of parameters such as mass. In the UK, commonly accepted safety criteria are applied to limit the k-effective of the system being assessed. These margins of subcriticality have no definitive justification to support the values chosen and might be considered rather arbitrary in nature. This paper aims to answer this question of suitability by investigating the relation between k-effective and the physical critical parameters for a wide range of systems. It concludes that the safety criteria currently applied in the UK are valid, but some difference exists between safety factors applied to the mass of fissile material present and the corresponding value of k-effective. (author)
Proceedings of the nuclear criticality technology safety project
Energy Technology Data Exchange (ETDEWEB)
Sanchez, R.G. [comp.
1997-06-01
This document contains summaries of the most of the papers presented at the 1994 Nuclear Criticality Technology Safety Project (NCTSP) meeting, which was held May 10 and 11 at Williamsburg, Va. The meeting was broken up into seven sessions, which covered the following topics: (1) Validation and Application of Calculations; (2) Relevant Experiments for Criticality Safety; (3) Experimental Facilities and Capabilities; (4) Rad-Waste and Weapons Disassembly; (5) Criticality Safety Software and Development; (6) Criticality Safety Studies at Universities; and (7) Training. The minutes and list of participants of the Critical Experiment Needs Identification Workgroup meeting, which was held on May 9 at the same venue, has been included as an appendix. A second appendix contains the names and addresses of all NCTSP meeting participants. Separate abstracts have been indexed to the database for contributions to this proceedings.
Proceedings of the nuclear criticality technology safety project
International Nuclear Information System (INIS)
Sanchez, R.G.
1997-06-01
This document contains summaries of the most of the papers presented at the 1994 Nuclear Criticality Technology Safety Project (NCTSP) meeting, which was held May 10 and 11 at Williamsburg, Va. The meeting was broken up into seven sessions, which covered the following topics: (1) Validation and Application of Calculations; (2) Relevant Experiments for Criticality Safety; (3) Experimental Facilities and Capabilities; (4) Rad-Waste and Weapons Disassembly; (5) Criticality Safety Software and Development; (6) Criticality Safety Studies at Universities; and (7) Training. The minutes and list of participants of the Critical Experiment Needs Identification Workgroup meeting, which was held on May 9 at the same venue, has been included as an appendix. A second appendix contains the names and addresses of all NCTSP meeting participants. Separate abstracts have been indexed to the database for contributions to this proceedings
International Nuclear Information System (INIS)
Vnukov, V.S.; Rjazanov, B.G.; Sviridov, V.I.; Frolov, V.V.; Zubkov, Y.N.
1991-01-01
The paper describes the general principles of nuclear criticality safety for handling, processing, transportation and fissile materials storing. Measures to limit the consequences of critical accidents are discussed for the fuel processing plants and fissile materials storage. The system of scientific and technical measures on nuclear criticality safety as well as the system of control and state supervision based on the rules, limits and requirements are described. The criticality safety aspects for various stages of handling nuclear materials are considered. The paper gives descriptions of the methods and approaches for critical risk assessments for the processing facilities, plants and storages. (Author)
Safety of Nuclear Power Plants: Design. Specific Safety Requirements
International Nuclear Information System (INIS)
2012-01-01
On the basis of the principles included in the Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, this Safety Requirements publication establishes requirements applicable to the design of nuclear power plants. It covers the design phase and provides input for the safe operation of the power plant. It elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.
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)
Use of a Web Site to Enhance Criticality Safety Training
International Nuclear Information System (INIS)
Huang, S T; Morman, J
2003-01-01
Currently, a website dedicated to enhancing communication and dissemination of criticality safety information is sponsored by the U.S. Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP). This website was developed as part of the DOE response to the Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 97-2, which reflected the need to make criticality safety information available to a wide audience. The website is the focal point for DOE nuclear criticality safety (NCS) activities, resources and references, including hyperlinks to other sites actively involved in the collection and dissemination of criticality safety information. The website is maintained by the Lawrence Livermore National Laboratory (LLNL) under auspices of the NCSP management. One area of the website contains a series of Nuclear Criticality Safety Engineer Training (NCSET) modules. During the past few years, many users worldwide have accessed the NCSET section of the NCSP website and have downloaded the training modules as an aid for their training programs. This trend was remarkable in that it points out a continuing need of the criticality safety community across the globe. It has long been recognized that training of criticality safety professionals is a continuing process involving both knowledge-based training and experience-based operations floor training. As more of the experienced criticality safety professionals reach retirement age, the opportunities for mentoring programs are reduced. It is essential that some method be provided to assist the training of young criticality safety professionals to replenish this limited human expert resource to support on-going and future nuclear operations. The main objective of this paper is to present the features of the NCSP website, including its mission, contents, and most importantly its use for the dissemination of training modules to the criticality safety community. We will discuss lessons learned and several ideas
Energy Technology Data Exchange (ETDEWEB)
White, W.F.
1997-05-13
The purpose of this document is to provide the definition and means of maintaining the Safety Envelope (SE) related to the Criticality Alarm System (CAS). This document provides amplification of the Limiting Condition for Operation (LCO) described in the Plutonium Finishing Plant (PFP) Operational Safety Requirements (OSR), WHC-SD-CP-OSR-010, Rev. 0, 1994, Section 3.1.2, Criticality Detectors and Alarms. This document, with its appendices, provides the following: (1) System functional requirements for determining system operability (Section 3); (2) A list of annotated system block diagrams which indicate the safety envelope boundaries (Appendix C); (3) A list of the Safety Class 1 and 2 Safety Envelope (SC-1/2 SE) equipment for input into the Master Component Index (Appendix B); (4) Functional requirements for individual SC-1/2 SE components, including appropriate setpoints and process parameters (Section 6 and Appendix A); (5) A list of the operational, maintenance and surveillance procedures necessary to operate and maintain the SC-1/2 SE components as required by the LCO (Section 6 and Appendix A).
International Nuclear Information System (INIS)
White, W.F.
1997-01-01
The purpose of this document is to provide the definition and means of maintaining the Safety Envelope (SE) related to the Criticality Alarm System (CAS). This document provides amplification of the Limiting Condition for Operation (LCO) described in the Plutonium Finishing Plant (PFP) Operational Safety Requirements (OSR), WHC-SD-CP-OSR-010, Rev. 0, 1994, Section 3.1.2, Criticality Detectors and Alarms. This document, with its appendices, provides the following: (1) System functional requirements for determining system operability (Section 3); (2) A list of annotated system block diagrams which indicate the safety envelope boundaries (Appendix C); (3) A list of the Safety Class 1 and 2 Safety Envelope (SC-1/2 SE) equipment for input into the Master Component Index (Appendix B); (4) Functional requirements for individual SC-1/2 SE components, including appropriate setpoints and process parameters (Section 6 and Appendix A); (5) A list of the operational, maintenance and surveillance procedures necessary to operate and maintain the SC-1/2 SE components as required by the LCO (Section 6 and Appendix A)
International Nuclear Information System (INIS)
2003-10-01
This proceedings contain (technical, oral and poster papers) presented papers at the Seventh International Conference on Nuclear Criticality Safety ICNC2003 held on 20-24 October 2003, in Tokai, Ibaraki, Japan, following ICNC'99 in Versailles, France. The theme of this conference is 'Challenges in the Pursuit of Global Nuclear Criticality Safety'. This proceedings represent the current status of nuclear criticality safety research throughout the world. The 81 of the presented papers are indexed individually. (J.P.N.)
International Nuclear Information System (INIS)
2003-10-01
This proceedings contain (technical, oral and poster papers) presented papers at the Seventh International Conference on Nuclear Criticality Safety ICNC2003 held on 20-24 October 2003, in Tokai, Ibaraki, Japan, following ICNC'99 in Versailles, France. The theme of this conference is 'Challenges in the Pursuit of Global Nuclear Criticality Safety'. This proceedings represent the current status of nuclear criticality safety research throughout the world. The 79 of the presented papers are indexed individually. (J.P.N.)
Safety assessment for facilities and activities. General safety requirements. Pt. 4
International Nuclear Information System (INIS)
2009-01-01
The Safety Fundamentals publication, Fundamental Safety Principles, establishes principles for ensuring the protection of workers, the public and the environment, now and in the future, from harmful effects of ionizing radiation. The objective of this Safety Requirements publication is to establish the generally applicable requirements to be fulfilled in safety assessment for facilities and activities, with special attention paid to defence in depth, quantitative analyses and the application of a graded approach to the ranges of facilities and of activities that are addressed. The publication also addresses the independent verification of the safety assessment that needs to be carried out by the originators and users of the safety assessment. This publication is intended to provide a consistent and coherent basis for safety assessment across all facilities and activities, which will facilitate the transfer of good practices between organizations conducting safety assessments and will assist in enhancing the confidence of all interested parties that an adequate level of safety has been achieved for facilities and activities. The requirements, which are derived from the Fundamental Safety Principles, relate to any human activity that may cause people to be exposed to radiation risks arising from facilities and activities, as follows: Facilities includes: (a) Nuclear power plants; (b) Other reactors (such as research reactors and critical assemblies); (c) Enrichment facilities and fuel fabrication facilities; (d) Conversion facilities used to generate UF 6 ; (e) Storage and reprocessing plants for irradiated fuel; (f) Facilities for radioactive waste management where radioactive waste is treated, conditioned, stored or disposed of; (g) Any other places where radioactive materials are produced, processed, used, handled or stored; (h) Irradiation facilities for medical, industrial, research and other purposes, and any places where radiation generators are installed; (i
Safety Assessment for Facilities and Activities. General Safety Requirements. Pt. 4
International Nuclear Information System (INIS)
2009-01-01
The Safety Fundamentals publication, Fundamental Safety Principles, establishes principles for ensuring the protection of workers, the public and the environment, now and in the future, from harmful effects of ionizing radiation. The objective of this Safety Requirements publication is to establish the generally applicable requirements to be fulfilled in safety assessment for facilities and activities, with special attention paid to defence in depth, quantitative analyses and the application of a graded approach to the ranges of facilities and of activities that are addressed. The publication also addresses the independent verification of the safety assessment that needs to be carried out by the originators and users of the safety assessment. This publication is intended to provide a consistent and coherent basis for safety assessment across all facilities and activities, which will facilitate the transfer of good practices between organizations conducting safety assessments and will assist in enhancing the confidence of all interested parties that an adequate level of safety has been achieved for facilities and activities. The requirements, which are derived from the Fundamental Safety Principles, relate to any human activity that may cause people to be exposed to radiation risks arising from facilities and activities, as follows: Facilities includes: (a) Nuclear power plants; (b) Other reactors (such as research reactors and critical assemblies); (c) Enrichment facilities and fuel fabrication facilities; (d) Conversion facilities used to generate UF6; (e) Storage and reprocessing plants for irradiated fuel; (f) Facilities for radioactive waste management where radioactive waste is treated, conditioned, stored or disposed of; (g) Any other places where radioactive materials are produced, processed, used, handled or stored; (h) Irradiation facilities for medical, industrial, research and other purposes, and any places where radiation generators are installed; (i
Safety Assessment for Facilities and Activities. General Safety Requirements. Pt. 4
International Nuclear Information System (INIS)
2010-01-01
The Safety Fundamentals publication, Fundamental Safety Principles, establishes principles for ensuring the protection of workers, the public and the environment, now and in the future, from harmful effects of ionizing radiation. The objective of this Safety Requirements publication is to establish the generally applicable requirements to be fulfilled in safety assessment for facilities and activities, with special attention paid to defence in depth, quantitative analyses and the application of a graded approach to the ranges of facilities and of activities that are addressed. The publication also addresses the independent verification of the safety assessment that needs to be carried out by the originators and users of the safety assessment. This publication is intended to provide a consistent and coherent basis for safety assessment across all facilities and activities, which will facilitate the transfer of good practices between organizations conducting safety assessments and will assist in enhancing the confidence of all interested parties that an adequate level of safety has been achieved for facilities and activities. The requirements, which are derived from the Fundamental Safety Principles, relate to any human activity that may cause people to be exposed to radiation risks arising from facilities and activities, as follows: Facilities includes: (a) Nuclear power plants; (b) Other reactors (such as research reactors and critical assemblies); (c) Enrichment facilities and fuel fabrication facilities; (d) Conversion facilities used to generate UF6; (e) Storage and reprocessing plants for irradiated fuel; (f) Facilities for radioactive waste management where radioactive waste is treated, conditioned, stored or disposed of; (g) Any other places where radioactive materials are produced, processed, used, handled or stored; (h) Irradiation facilities for medical, industrial, research and other purposes, and any places where radiation generators are installed; (i
Safety Assessment for Facilities and Activities. General Safety Requirements. Pt. 4
International Nuclear Information System (INIS)
2009-01-01
The Safety Fundamentals publication, Fundamental Safety Principles, establishes principles for ensuring the protection of workers, the public and the environment, now and in the future, from harmful effects of ionizing radiation.? read more The objective of this Safety Requirements publication is to establish the generally applicable requirements to be fulfilled in safety assessment for facilities and activities, with special attention paid to defence in depth, quantitative analyses and the application of a graded approach to the ranges of facilities and of activities that are addressed. The publication also addresses the independent verification of the safety assessment that needs to be carried out by the originators and users of the safety assessment. This publication is intended to provide a consistent and coherent basis for safety assessment across all facilities and activities, which will facilitate the transfer of good practices between organizations conducting safety assessments and will assist in enhancing the confidence of all interested parties that an adequate level of safety has been achieved for facilities and activities. The requirements, which are derived from the Fundamental Safety Principles, relate to any human activity that may cause people to be exposed to radiation risks arising from facilities and activities, as follows: Facilities includes: (a) Nuclear power plants; (b) Other reactors (such as research reactors and critical assemblies); (c) Enrichment facilities and fuel fabrication facilities; (d) Conversion facilities used to generate UF6; (e) Storage and reprocessing plants for irradiated fuel; (f) Facilities for radioactive waste management where radioactive waste is treated, conditioned, stored or disposed of; (g) Any other places where radioactive materials are produced, processed, used, handled or stored; (h) Irradiation facilities for medical, industrial, research and other purposes, and any places where radiation generators are
75 FR 60129 - Draft Guidance for Industry and Investigators on Safety Reporting Requirements for...
2010-09-29
...., Bldg. 51, rm. 2201, Silver Spring, MD 20993-0002; or the Office of Communication, Outreach, and...'s ability to review critical safety information, improve safety monitoring of human drug and..., will represent the Agency's current thinking on safety reporting requirements for INDs and BA/BE...
Criticality safety studies at VTT Energy
International Nuclear Information System (INIS)
Roine, T.; Anttila, M.
1995-01-01
At VTT Energy a compact reactor physics calculation system is applied in many kind of problems. Generation of group constants for static and dynamic core calculations, flux and dose rate calculations as well as criticality safety studies are performed basically with the same codes. In the presentation a short overview of the wide variety of criticality safety problems analyzed at VTT Energy is given. The calculation system with some illustrative examples is also described. (12 refs., 1 tab.)
Isotopic dilution requirements for 233U criticality safety in processing and disposal facilities
International Nuclear Information System (INIS)
Elam, K.R.; Forsberg, C.W.; Hopper, C.M.; Wright, R.Q.
1997-11-01
The disposal of excess 233 U as waste is being considered. Because 233 U is a fissile material, one of the key requirements for processing 233 U to a final waste form and disposing of it is to avoid nuclear criticality. For many processing and disposal options, isotopic dilution is the most feasible and preferred option to avoid nuclear criticality. Isotopic dilution is dilution of fissile 233 U with nonfissile 238 U. The use of isotopic dilution removes any need to control nuclear criticality in process or disposal facilities through geometry or chemical composition. Isotopic dilution allows the use of existing waste management facilities, that are not designed for significant quantities of fissile materials, to be used for processing and disposing of 233 U. The amount of isotopic dilution required to reduce criticality concerns to reasonable levels was determined in this study to be ∼ 0.66 wt% 233 U. The numerical calculations used to define this limit consisted of a homogeneous system of silicon dioxide (SiO 2 ), water (H 2 O), 233 U, and depleted uranium (DU) in which the ratio of each component was varied to determine the conditions of maximum nuclear reactivity. About 188 parts of DU (0.2 wt% 235 U) are required to dilute 1 part of 233 U to this limit in a water-moderated system with no SiO 2 present. Thus, for the US inventory of 233 U, several hundred metric tons of DU would be required for isotopic dilution
Recent and proposed changes in criticality alarm system requirements
International Nuclear Information System (INIS)
Putman, V.L.
1998-01-01
Various changes in criticality alarm system (CAS) requirements of American Nuclear Society (ANS) standards, US Department of Energy (DOE) orders, US Nuclear Regulatory Commission (NRC) regulations and guidance, and Occupational Safety and Health Administration (OSHA) standards or regulations were approved or proposed in the last 5 yr. Many changes interpreted or clarified existing requirements or accommodated technological or organizational developments. However, some changes could substantively affect CAS programs, including several changes originally thought to be editorial. These changes are discussed here
Graydon, Patrick J.; Holloway, C. M.
2015-01-01
Safe use of software in safety-critical applications requires well-founded means of determining whether software is fit for such use. While software in industries such as aviation has a good safety record, little is known about whether standards for software in safety-critical applications 'work' (or even what that means). It is often (implicitly) argued that software is fit for safety-critical use because it conforms to an appropriate standard. Without knowing whether a standard works, such reliance is an experiment; without carefully collecting assessment data, that experiment is unplanned. To help plan the experiment, we organized a workshop to develop practical ideas for assessing software safety standards. In this paper, we relate and elaborate on the workshop discussion, which revealed subtle but important study design considerations and practical barriers to collecting appropriate historical data and recruiting appropriate experimental subjects. We discuss assessing standards as written and as applied, several candidate definitions for what it means for a standard to 'work,' and key assessment strategies and study techniques and the pros and cons of each. Finally, we conclude with thoughts about the kinds of research that will be required and how academia, industry, and regulators might collaborate to overcome the noted barriers.
Energy Technology Data Exchange (ETDEWEB)
Nirider, L. Tom
2003-08-06
This document was designed as a reference and a primer for facility and project managers responsible for Deactivation and Decommissioning (D&D) processes in facilities containing significant inventories of fissionable materials. The document contains lessons learned and guidance for the development and management of criticality safety programs. It also contains information gleaned from occurrence reports, assessment reports, facility operations and management, NDA program reviews, criticality safety experts, and criticality safety evaluations. This information is designed to assist in the planning process and operational activities. Sufficient details are provided to allow the reader to understand the events, the lessons learned, and how to apply the information to present or planned D&D processes. Information is also provided on general lessons learned including criticality safety evaluations and criticality safety program requirements during D&D activities. The document also explores recent and past criticality accidents in operating facilities, and it extracts lessons learned pertinent to D&D activities. A reference section is included to provide additional information. This document does not address D&D lessons learned that are not pertinent to criticality safety.
The automatic programming for safety-critical software in nuclear power plants
Energy Technology Data Exchange (ETDEWEB)
Kim, Jang Yeol; Eom, Heung Seop; Choi, You Rark
1998-06-01
We defined the Korean unique safety-critical software development methodology by modifying Dr. Harel`s statechart-based on formal methods in order to digitalized the reactor protection system. It is suggested software requirement specification guideline to specify design specification which is basis for requirement specification and automatic programming by the caused by shutdown parameter logic of the steam generator water level for Wolsung 2/3/4 unit SDS no.1 and simulated it by binding the Graphic User Interface (GUI). We generated the K and R C code automatically by utilizing the Statemate MAGNUM Sharpshooter/C code generator. Auto-generated K and R C code is machine independent code and has high productivity, quality and provability. The following are the summaries of major research and development. - Set up the Korean unique safety-critical software development methodology - Developed software requirement specification guidelines - Developed software design specification guidelines - Reactor trip modeling for steam generator waster level Wolsung 2/3/4 SDS no. 1 shutdown parameter logic - Graphic panel binding with GUI. (author). 20 refs., 12 tabs., 15 figs
The automatic programming for safety-critical software in nuclear power plants
International Nuclear Information System (INIS)
Kim, Jang Yeol; Eom, Heung Seop; Choi, You Rark
1998-06-01
We defined the Korean unique safety-critical software development methodology by modifying Dr. Harel's statechart-based on formal methods in order to digitalized the reactor protection system. It is suggested software requirement specification guideline to specify design specification which is basis for requirement specification and automatic programming by the caused by shutdown parameter logic of the steam generator water level for Wolsung 2/3/4 unit SDS no.1 and simulated it by binding the Graphic User Interface (GUI). We generated the K and R C code automatically by utilizing the Statemate MAGNUM Sharpshooter/C code generator. Auto-generated K and R C code is machine independent code and has high productivity, quality and provability. The following are the summaries of major research and development. - Set up the Korean unique safety-critical software development methodology - Developed software requirement specification guidelines - Developed software design specification guidelines - Reactor trip modeling for steam generator waster level Wolsung 2/3/4 SDS no. 1 shutdown parameter logic - Graphic panel binding with GUI. (author). 20 refs., 12 tabs., 15 figs
The Health and Safety Executive's regulatory framework for control of nuclear criticality safety
International Nuclear Information System (INIS)
Smith, K.; Simister, D.N.
1991-01-01
In the United Kingdom the Health and Safety at Work Act, 1974 is the main legal instrument under which risks to people from work activities are controlled. Certain sections of the Nuclear Installations Act, 1965 which deal with the licensing of nuclear sites and the regulatory control of risks arising from them, including the risk from accidental criticality, are relevant statutory provisions of the Health and Safety at Work Act. The responsibility for safety rests with the operator who has to make and implement arrangements to prevent accidental criticality. The adequacy of these arrangements must be demonstrated in a safety case to the regulatory authorities. Operators are encouraged to treat each plant on its own merits and develop the safety case accordingly. The Nuclear Installations Inspectorate (NII), for its part, assesses the adequacy of the operator's safety case against the industry's own standards and criteria, but more particularly against the NII's safety assessment principles and guides, and international standards. Risks should be made as low as reasonably practicable. Generally, the NII seeks improvements in safety using an enforcement policy which operates at a number of levels, ranging from persuasion through discussion to the ultimate deterrent of withdrawal of a site licence. This paper describes the role of the NII, which includes a specialist criticality expertise, within the Health and Safety Executive, in regulating the nuclear sites from the criticality safety viewpoint. (Author)
Nuclear criticality safety basics for personnel working with nuclear fissionable materials. Phase I
International Nuclear Information System (INIS)
Vausher, A.L.
1984-10-01
DOE order 5480.1A, Chapter V, ''Safety of Nuclear Facilities,'' establishes safety procedures and requirements for DOE nuclear facilities. The ''Nuclear Criticality Safety Basic Program - Phase I'' is documented in this report. The revised program has been developed to clearly illustrate the concept of nuclear safety and to help the individual employee incorporate safe behavior in his daily work performance. Because of this, the subject of safety has been approached through its three fundamentals: scientific basis, engineering criteria, and administrative controls. Only basics of these three elements were presented. 5 refs
Multiprocessor Priority Ceiling Emulation for Safety-Critical Java
DEFF Research Database (Denmark)
Strøm, Torur Biskopstø; Schoeberl, Martin
2015-01-01
Priority ceiling emulation has preferable properties on uniprocessor systems, such as avoiding priority inversion and being deadlock free. This has made it a popular locking protocol. According to the safety-critical Java specication, priority ceiling emulation is a requirement for implementations....... However, implementing the protocol for multiprocessor systemsis more complex so implementations might perform worse than non-preemptive implementations. In this paper we compare two multiprocessor lock implementations with hardware support for the Java optimized processor: non-preemptive locking...
A Methodological Framework for Software Safety in Safety Critical Computer Systems
P. V. Srinivas Acharyulu; P. Seetharamaiah
2012-01-01
Software safety must deal with the principles of safety management, safety engineering and software engineering for developing safety-critical computer systems, with the target of making the system safe, risk-free and fail-safe in addition to provide a clarified differentaition for assessing and evaluating the risk, with the principles of software risk management. Problem statement: Prevailing software quality models, standards were not subsisting in adequately addressing the software safety ...
Proceedings of KURRI symposium on criticality safety
International Nuclear Information System (INIS)
Nishina, Kojiro; Kanda, Keiji
1984-01-01
On August 8, 1984, at the Reactor Application Center of the Research Reactor Institute, Kyoto University, the symposium on criticality safety was held, and 81 participants from various fields of reactor physics, nuclear fuel cycle engineering, reactor chemistry, nuclear chemistry, health physics and so on discussed the problem. The gists of the presentation are collected in this report. The contents are the techniques of evaluating criticality safety in respective fuel facilities, the system of control and its concept, the course and plan of the research on criticality safety in Japan and foreign countries, the techniques of determining multiplication factor and so on, and the review of present status, the pointing-out of problems and the report of new techniques were made. The measures coping with criticality safety have been mostly to meet urgent demand, but its fundamental examination and long term research should be carried out. This symposium was planned as the preparation for such research project, and favorable comment was given by the participants. In the next symposium, it is considered better to limit the themes and to allot more time to respective lectures. (Kako, I.)
Requirements on waste forms for the planned Konrad repository based on criticality calculations
International Nuclear Information System (INIS)
Berg, H.P.
1988-02-01
In the framework of the safety analyses for the planned Konrad repository it has been investigated whether a criticality incident may be possible during the operational phase or in the post-operational phase. The analysis has shown that the criticality safety is ensured by limitation of a mass concentration of the fissile material in the waste form group and by determination of a maximum permissible mass of fissile material per waste package. The resulting requirements of the waste packages, including a mixture in the cross-section of an emplacement room, are explained. (orig.) [de
OECD/NEA working party on nuclear criticality safety: Challenge of new realities
International Nuclear Information System (INIS)
Nomura, Y.; Brady, M.C.; Briggs, J.B.; Sartori, E.
1998-01-01
New issues in criticality safety continue to emerge as spent fuel storage facilities reach the saturation point, fuel enrichments and burn-ups increase and new types of plutonium-carrying fuels are being developed. The new challenges related to the manipulation, transportation and storage of fuel demand further work to improve models predicting behavior through new experiments, especially where there is a lack of data in the present databases. This article summarizes the activities of the OECD/NEA working groups that coordinate and carry out work in the domain of criticality safety. Particular attention is devoted to establishing sound databases required in this area and to addressing issues of high relevance such as burn-up credit. This is aimed toward improving safety and identifying economic solutions to issues concerning the back end of the fuel cycle
SCALE 5: Powerful new criticality safety analysis tools
International Nuclear Information System (INIS)
Bowman, Stephen M.; Hollenbach, Daniel F.; Dehart, Mark D.; Rearden, Bradley T.; Gauld, Ian C.; Goluoglu, Sedat
2003-01-01
Version 5 of the SCALE computer software system developed at Oak Ridge National Laboratory, scheduled for release in December 2003, contains several significant new modules and sequences for criticality safety analysis and marks the most important update to SCALE in more than a decade. This paper highlights the capabilities of these new modules and sequences, including continuous energy flux spectra for processing multigroup problem-dependent cross sections; one- and three-dimensional sensitivity and uncertainty analyses for criticality safety evaluations; two-dimensional flexible mesh discrete ordinates code; automated burnup-credit analysis sequence; and one-dimensional material distribution optimization for criticality safety. (author)
SCALE Graphical Developments for Improved Criticality Safety Analyses
International Nuclear Information System (INIS)
Barnett, D.L.; Bowman, S.M.; Horwedel, J.E.; Petrie, L.M.
1999-01-01
New computer graphic developments at Oak Ridge National Ridge National Laboratory (ORNL) are being used to provide visualization of criticality safety models and calculational results as well as tools for criticality safety analysis input preparation. The purpose of this paper is to present the status of current development efforts to continue to enhance the SCALE (Standardized Computer Analyses for Licensing Evaluations) computer software system. Applications for criticality safety analysis in the areas of 3-D model visualization, input preparation and execution via a graphical user interface (GUI), and two-dimensional (2-D) plotting of results are discussed
International Nuclear Information System (INIS)
NIRIDER, L.T.
2003-01-01
This document was designed as a reference and a primer for facility and project managers responsible for Deactivation and Decommissioning (D and D) processes in facilities containing significant inventories of fissionable materials. The document contains lessons learned and guidance for the development and management of criticality safety programs. It also contains information gleaned from occurrence reports, assessment reports, facility operations and management, NDA program reviews, criticality safety experts, and criticality safety evaluations. This information is designed to assist in the planning process and operational activities. Sufficient details are provided to allow the reader to understand the events, the lessons learned, and how to apply the information to present or planned D and D processes. Information is also provided on general lessons learned including criticality safety evaluations and criticality safety program requirements during D and D activities. The document also explores recent and past criticality accidents in operating facilities, and it extracts lessons learned pertinent to D and D activities. A reference section is included to provide additional information. This document does not address D and D lessons learned that are not pertinent to criticality safety
Criticality Safety Information Resource Center Web portal: www.csirc.net
International Nuclear Information System (INIS)
Harmon, C.D. II; Jones, T.
2000-01-01
The Nuclear Criticality Safety Group (ESH-6) at Los Alamos National Laboratory (LANL) is in the process of collecting and archiving historical and technical information related to nuclear criticality safety from LANL and other facilities. In an ongoing effort, this information is being made available via the Criticality Safety Information Resource Center (CSIRC) web site, which is hosted and maintained by ESH-6 staff. Recently, the CSIRC Web site was recreated as a Web portal that provides the criticality safety community with much more than just archived data
Development of an FPGA-based controller for safety critical application
International Nuclear Information System (INIS)
Xing, A.; De Grosbois, J.; Sklyar, V.; Archer, P.; Awwal, A.
2011-01-01
In implementing safety functions, Field Programmable Gate Arrays (FPGA) technology offers a distinct combination of benefits and advantages over microprocessor-based systems. FPGAs can be designed such that the final product is purely hardware, without any overhead runtime software, bringing the design closer to a conventional hardware-based solution. On the other hand, FPGAs can implement more complex safety logic that would generally require microprocessor-based safety systems. There are now qualified FPGA-based platforms available on the market with a credible use history in safety applications in nuclear power plants. Atomic Energy of Canada (AECL), in collaboration with RPC Radiy, has initiated a development program to define a vigorous FPGA engineering process suitable for implementing safety critical functions at the application development level. This paper provides an update on the FPGA development program along with the proposed design model using function block diagrams for the development of safety controllers in CANDU applications. (author)
Concepts and techniques: Active electronics and computers in safety-critical accelerator operation
International Nuclear Information System (INIS)
Frankel, R.S.
1995-01-01
The Relativistic Heavy Ion Collider (RHIC) under construction at Brookhaven National Laboratory, requires an extensive Access Control System to protect personnel from Radiation, Oxygen Deficiency and Electrical hazards. In addition, the complicated nature of operation of the Collider as part of a complex of other Accelerators necessitates the use of active electronic measurement circuitry to ensure compliance with established Operational Safety Limits. Solutions were devised which permit the use of modern computer and interconnections technology for Safety-Critical applications, while preserving and enhancing, tried and proven protection methods. In addition a set of Guidelines, regarding required performance for Accelerator Safety Systems and a Handbook of design criteria and rules were developed to assist future system designers and to provide a framework for internal review and regulation
Concepts and techniques: Active electronics and computers in safety-critical accelerator operation
Energy Technology Data Exchange (ETDEWEB)
Frankel, R.S.
1995-12-31
The Relativistic Heavy Ion Collider (RHIC) under construction at Brookhaven National Laboratory, requires an extensive Access Control System to protect personnel from Radiation, Oxygen Deficiency and Electrical hazards. In addition, the complicated nature of operation of the Collider as part of a complex of other Accelerators necessitates the use of active electronic measurement circuitry to ensure compliance with established Operational Safety Limits. Solutions were devised which permit the use of modern computer and interconnections technology for Safety-Critical applications, while preserving and enhancing, tried and proven protection methods. In addition a set of Guidelines, regarding required performance for Accelerator Safety Systems and a Handbook of design criteria and rules were developed to assist future system designers and to provide a framework for internal review and regulation.
Applications of PRA in nuclear criticality safety
International Nuclear Information System (INIS)
McLaughlin, T.P.
1992-01-01
Traditionally, criticality accident prevention at Los Alamos has been based on a thorough review and understanding of proposed operations of changes to operations, involving both process supervision and criticality safety staff. The outcome of this communication was usually an agreement, based on professional judgement, that certain accident sequences were credible and had to be reduced in likelihood either by administrative controls or by equipment design and others were not credible, and thus did not warrant expenditures to further reduce their likelihood. The extent of analysis and documentation was generally in proportion to the complexity of the operation but did not include quantified risk assessments. During the last three years nuclear criticality safety related Probabilistic Risk Assessments (PRAs) have been preformed on operations in two Los Alamos facilities. Both of these were conducted in order to better understand the cost/benefit aspects of PRA's as they apply to largely ''hands-on'' operations with fissile material for which human errors or equipment failures significant to criticality safety are both rare and unique. Based on these two applications and an appreciation of the historical criticality accident record (frequency and consequences) it is apparent that quantified risk assessments should be performed very selectively
Safety of nuclear fuel cycle facilities. Safety requirements
International Nuclear Information System (INIS)
2008-01-01
This publication covers the broad scope of requirements for fuel cycle facilities that, in light of the experience and present state of technology, must be satisfied to ensure safety for the lifetime of the facility. Topics of specific reference include aspects of nuclear fuel generation, storage, reprocessing and disposal. Contents: 1. Introduction; 2. The safety objective, concepts and safety principles; 3. Legal framework and regulatory supervision; 4. The management system and verification of safety; 5. Siting of the facility; 6. Design of the facility; 7. Construction of the facility; 8. Commissioning of the facility; 9. Operation of the facility; 10. Decommissioning of the facility; Appendix I: Requirements specific to uranium fuel fabrication facilities; Appendix II: Requirements specific to mixed oxide fuel fabrication facilities; Appendix III: Requirements specific to conversion facilities and enrichment facilities
Verification of safety critical software
International Nuclear Information System (INIS)
Son, Ki Chang; Chun, Chong Son; Lee, Byeong Joo; Lee, Soon Sung; Lee, Byung Chai
1996-01-01
To assure quality of safety critical software, software should be developed in accordance with software development procedures and rigorous software verification and validation should be performed. Software verification is the formal act of reviewing, testing of checking, and documenting whether software components comply with the specified requirements for a particular stage of the development phase[1]. New software verification methodology was developed and was applied to the Shutdown System No. 1 and 2 (SDS1,2) for Wolsung 2,3 and 4 nuclear power plants by Korea Atomic Energy Research Institute(KAERI) and Atomic Energy of Canada Limited(AECL) in order to satisfy new regulation requirements of Atomic Energy Control Boars(AECB). Software verification methodology applied to SDS1 for Wolsung 2,3 and 4 project will be described in this paper. Some errors were found by this methodology during the software development for SDS1 and were corrected by software designer. Outputs from Wolsung 2,3 and 4 project have demonstrated that the use of this methodology results in a high quality, cost-effective product. 15 refs., 6 figs. (author)
Recommendations for preparing the criticality safety evaluation of transportation packages
International Nuclear Information System (INIS)
Dyer, H.R.; Parks, C.V.
1997-04-01
This report provides recommendations on preparing the criticality safety section of an application for approval of a transportation package containing fissile material. The analytical approach to the evaluation is emphasized rather than the performance standards that the package must meet. Where performance standards are addressed, this report incorporates the requirements of 10 CFR Part 71. 12 refs., 6 figs., 8 tabs
Lecture notes for criticality safety
International Nuclear Information System (INIS)
Fullwood, R.
1992-03-01
These lecture notes for criticality safety are prepared for the training of Department of Energy supervisory, project management, and administrative staff. Technical training and basic mathematics are assumed. The notes are designed for a two-day course, taught by two lecturers. Video tapes may be used at the options of the instructors. The notes provide all the materials that are necessary but outside reading will assist in the fullest understanding. The course begins with a nuclear physics overview. The reader is led from the macroscopic world into the microscopic world of atoms and the elementary particles that constitute atoms. The particles, their masses and sizes and properties associated with radioactive decay and fission are introduced along with Einstein's mass-energy equivalence. Radioactive decay, nuclear reactions, radiation penetration, shielding and health-effects are discussed to understand protection in case of a criticality accident. Fission, the fission products, particles and energy released are presented to appreciate the dangers of criticality. Nuclear cross sections are introduced to understand the effectiveness of slow neutrons to produce fission. Chain reactors are presented as an economy; effective use of the neutrons from fission leads to more fission resulting in a power reactor or a criticality excursion. The six-factor formula is presented for managing the neutron budget. This leads to concepts of material and geometric buckling which are used in simple calculations to assure safety from criticality. Experimental measurements and computer code calculations of criticality are discussed. To emphasize the reality, historical criticality accidents are presented in a table with major ones discussed to provide lessons-learned. Finally, standards, NRC guides and regulations, and DOE orders relating to criticality protection are presented
OECD/NEA working party on nuclear criticality safety: challenge of new realities
International Nuclear Information System (INIS)
Nomura, Y.; Brady, M.C.; Briggs, J.B.; Sartori, E.
1998-01-01
New issues in critically safety continue to emerge as spent fuel storage facilities reach the saturation point, fuel enrichments and burn-ups increase and new types of plutonium-carrying fuels are being developed. The new challenges related to the manipulation, transportation and storage of fuel demand further work to improve models predicting behaviour through new experiments, especially where there is a lack of data the present databases. This article summarizes the activities of the OECD/NEA working groups that co-ordinate and carry out work in the domain of criticality safety. Particular attention is devoted to establishing sound databases required in this area and to addressing issues of high relevance such as burn-up credit. This is aimed toward improving safety and identifying economic solutions to issues concerning the back end of the fuel cycle. (authors)
International Nuclear Information System (INIS)
Ahmed, Rizwan; Koo, June Mo; Jeong, Yong Hoon; Heo, Gyunyoung
2011-01-01
A safety-critical system has to qualify the performance-related requirements and the safety-related requirements simultaneously. Conceptually, design processes should consider both of them simultaneously but the practices do not and/or cannot follow such a theoretical approach due to the limitation of design resources. From our experience, we found that safety-related functions must be simultaneously resolved with the development of performance-related functions, particularly, in case of safety-critical systems. Since, success and failure domain analyses are essential for the investigation of performance-related and safety-related requirements, respectively, we articulated our perception to Axiomatic Design (AD), Fault Tree Analysis (FTA), and TRIZ. A design evolution procedure considering feedbacks from AD to identify functional couplings, TRIZ methodology to explore uncoupling solutions and FTA to improve reliability in a systematic way is presented here. A case study regarding design of safety injection tank installed in a nuclear power plant is also included to illustrate the proposed framework. It is expected that several iterations between AD-TRIZ-FTA would result into an optimized design which could be tested against the desired performance and safety criteria.
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Rizwan; Koo, June Mo [Department of Nuclear Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Heo, Gyunyoung, E-mail: gheo@khu.ac.k [Department of Nuclear Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)
2011-01-15
A safety-critical system has to qualify the performance-related requirements and the safety-related requirements simultaneously. Conceptually, design processes should consider both of them simultaneously but the practices do not and/or cannot follow such a theoretical approach due to the limitation of design resources. From our experience, we found that safety-related functions must be simultaneously resolved with the development of performance-related functions, particularly, in case of safety-critical systems. Since, success and failure domain analyses are essential for the investigation of performance-related and safety-related requirements, respectively, we articulated our perception to Axiomatic Design (AD), Fault Tree Analysis (FTA), and TRIZ. A design evolution procedure considering feedbacks from AD to identify functional couplings, TRIZ methodology to explore uncoupling solutions and FTA to improve reliability in a systematic way is presented here. A case study regarding design of safety injection tank installed in a nuclear power plant is also included to illustrate the proposed framework. It is expected that several iterations between AD-TRIZ-FTA would result into an optimized design which could be tested against the desired performance and safety criteria.
Implications of Monte Carlo Statistical Errors in Criticality Safety Assessments
International Nuclear Information System (INIS)
Pevey, Ronald E.
2005-01-01
Most criticality safety calculations are performed using Monte Carlo techniques because of Monte Carlo's ability to handle complex three-dimensional geometries. For Monte Carlo calculations, the more histories sampled, the lower the standard deviation of the resulting estimates. The common intuition is, therefore, that the more histories, the better; as a result, analysts tend to run Monte Carlo analyses as long as possible (or at least to a minimum acceptable uncertainty). For Monte Carlo criticality safety analyses, however, the optimization situation is complicated by the fact that procedures usually require that an extra margin of safety be added because of the statistical uncertainty of the Monte Carlo calculations. This additional safety margin affects the impact of the choice of the calculational standard deviation, both on production and on safety. This paper shows that, under the assumptions of normally distributed benchmarking calculational errors and exact compliance with the upper subcritical limit (USL), the standard deviation that optimizes production is zero, but there is a non-zero value of the calculational standard deviation that minimizes the risk of inadvertently labeling a supercritical configuration as subcritical. Furthermore, this value is shown to be a simple function of the typical benchmarking step outcomes--the bias, the standard deviation of the bias, the upper subcritical limit, and the number of standard deviations added to calculated k-effectives before comparison to the USL
International Nuclear Information System (INIS)
Sheaffer, M.K.; Keeton, S.C.; Lutz, H.F.
1995-06-01
This report evaluates nuclear criticality safety for large cylinder cleaning operations in the Decontamination and Recovery Facility, X-705, at the Portsmouth Gaseous Diffusion Plant. A general description of current cleaning procedures and required hardware/equipment is presented, and documentation for large cylinder cleaning operations is identified and described. Control parameters, design features, administrative controls, and safety systems relevant to nuclear criticality are discussed individually, followed by an overall assessment based on the Double Contingency Principle. Recommendations for enhanced safety are suggested, and issues for increased efficiency are presented
SCALE criticality safety verification and validation package
International Nuclear Information System (INIS)
Bowman, S.M.; Emmett, M.B.; Jordan, W.C.
1998-01-01
Verification and validation (V and V) are essential elements of software quality assurance (QA) for computer codes that are used for performing scientific calculations. V and V provides a means to ensure the reliability and accuracy of such software. As part of the SCALE QA and V and V plans, a general V and V package for the SCALE criticality safety codes has been assembled, tested and documented. The SCALE criticality safety V and V package is being made available to SCALE users through the Radiation Safety Information Computational Center (RSICC) to assist them in performing adequate V and V for their SCALE applications
International Nuclear Information System (INIS)
Jung, Jae Cheon; Chang, Hoon Seon; Chang, Young Woo; Kim, Jae Hack; Sohn, Se Do
2005-01-01
The major issues of the safety critical software are formalism and V and V. Implementing these two characteristics in the safety critical software will greatly enhance the quality of software product. The structure based development requires lots of output documents from the requirements phase to the testing phase. The requirements analysis phase is open omitted. According to the Standish group report in 2001, 49% of software project is cancelled before completion or never implemented. In addition, 23% is completed and become operational, but over-budget, over the time estimation, and with fewer features and functions than initially specified. They identified ten success factors. Among them, firm basic requirements and formal methods are technically achievable factors while the remaining eight are management related. Misunderstanding of requirements due to lack of communication between the design engineer and verification engineer causes unexpected result such as functionality error of system. Safety critical software shall comply with such characteristics as; modularity, simplicity, minimizing the sub-routine, and excluding the interrupt routine. In addition, the crosslink fault and erroneous function shall be eliminated. The easiness of repairing work after the installation shall be achieved as well. In consideration of the above issues, we evaluate the model driven development (MDD) methods for nuclear I and C systems software. For qualitative analysis, the unified modeling language (UML), functional block language (FBL) and the safety critical application environment (SCADE) are tested for the above characteristics
International Nuclear Information System (INIS)
Rathbun, R.
1994-01-01
Review of SRT-CMA-940003, ''Phase I Criticality Analysis For The 9972-9975 Family Of Shipping Casks (U). (SRT-CMA-940003).'' January 22, 1994, has been performed by the SRTC Applied Physics Group. The NCSE is a criticality assessment of the 9972-9975 family of shipping casks. This work is a follow-on of a previous criticality safety evaluation, with the differences between this and the previous evaluation are that now wall tolerances are modeled and more sophisticated analytical methods are applied. The NCSE under review concludes that, with one exception, the previously specified plutonium and uranium mass limits for 9972-9975 family of shipping casks do ensure that WSRC Nuclear Criticality Safety Manual requirements (ref. 1) are satisfied. The one exception is that the plutonium mass limit for the 9974 cask had to be reduced from 4.4 to 4.3 kg. In contrast, the 7.5 kg uranium mass limit for the 9974 cask was raised to 14.5 kg, making the uranium mass identical for all casks in this family. This technical review consisted of an independent check of the methods and models employed, application of ANSI/ANS 8.1 and 8.15, and verification of WSRC Nuclear Criticality Safety Manual procedures
An integrated environment of software development and V and V for PLC based safety-critical systems
International Nuclear Information System (INIS)
Koo, Seo Ryong
2005-02-01
To develop and implement a safety-critical system, the requirements of the system must be analyzed thoroughly during the phases of a software development's life cycle because a single error in the requirements can generate serious software faults. We therefore propose an Integrated Environment (IE) approach for requirements which is an integrated approach that enables easy inspection by combining requirement traceability and effective use of a formal method. For the V and V tasks of requirements phase, our approach uses software inspection, requirement traceability, and formal specification with structural decomposition. Software inspection and the analysis of requirements traceability are the most effective methods of software V and V. Although formal methods are also considered an effective V and V activity, they are difficult to use properly in nuclear fields, as well as in other fields, because of their mathematical nature. We also propose another Integrated Environment (IE) for the design and implementation of safety-critical systems. In this study, a nuclear FED-style design specification and analysis (NuFDS) approach was proposed for PLC based safety-critical systems. The NuFDS approach is suggested in a straightforward manner for the effective and formal specification and analysis of software designs. Accordingly, the proposed NuFDS approach comprises one technique for specifying the software design and another for analyzing the software design. In addition, with the NuFDS approach, we can analyze the safety of software on the basis of fault tree synthesis. To analyze the design phase more effectively, we propose a technique of fault tree synthesis, along with a universal fault tree template for the architecture modules of nuclear software. Various tools have been needed to make software V and V more convenient. We therefore developed four kinds of computer-aided software engineering tools that could be used in accordance with the software's life cycle to
Leadership and Management for Safety. General Safety Requirements
International Nuclear Information System (INIS)
2016-01-01
This Safety Requirements publication establishes requirements that support Principle 3 of the Fundamental Safety Principles in relation to establishing, sustaining and continuously improving leadership and management for safety and an integrated management system. It emphasizes that leadership for safety, management for safety, an effective management system and a systemic approach (i.e. an approach in which interactions between technical, human and organizational factors are duly considered) are all essential to the specification and application of adequate safety measures and to the fostering of a strong safety culture. Leadership and an effective management system will integrate safety, health, environmental, security, quality, human-and-organizational factor, societal and economic elements. The management system will ensure the fostering of a strong safety culture, regular assessment of performance and the application of lessons from experience. The publication is intended for use by regulatory bodies, operating organizations (registrants and licensees) and other organizations concerned with facilities and activities that give rise to radiation risks
Criticality safety (prospect of study in NUCEF)
International Nuclear Information System (INIS)
Itagaki, Masafumi
1996-01-01
Experimental studies of criticality safety are under way using STACY and TRACY in NUCEF. Collection of fundamental data on criticality in a solution system is undergoing with STACY to confirm that the likelihood of criticality safety in the system constructed on the assumption of apparatuses in a reprocessing plant is enough large. Whereas some experiments simulating criticality accidents in a reprocessing plant using TRACY were designed to investigate the behaviors of fuel solution and radioactive matters in order to clarify whether it is possible to safely shut them in the facility even if a critical accident occurs. Both STACY and TRACY reached the criticality in 1995. Up to now a series of criticality experiments have been done using STACY with a core tank φ60 cm and the first periodical examination is now under way. On the other hand, we have a plan using TRACY to investigate the behaviors of nuclear heat solution at a criticality accident, and the releasing, transfer and deposition of radioactive materials. After reaching the criticality for the first, the performance verification test has been conducted. The full-scale study using TRACY is planned to begin in the second half of 1996. (M.N.)
Nuclear criticality safety program at the University of Tennessee-Knoxville
International Nuclear Information System (INIS)
Basoglu, B.; Bentley, C.; Brewer, R.; Dunn, M.; Haught, C.; Plaster, M.; Wilkinson, A.; Dodds, H.; Elliott, E.; Waddell, W.
1993-01-01
This paper presents an overview of the nuclear criticality safety (NCS) educational program at the University of Tennessee-Knoxville. The program is an academic specialization for nuclear engineering graduate students pursuing either the MS or PhD degree and includes special NCS courses and NCS research projects. Both the courses and the research projects serve as partial fulfillment of the requirements for the degree being pursued
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 of Nuclear Power Plants: Design. Specific Safety Requirements (Chinese Ed.)
International Nuclear Information System (INIS)
2012-01-01
On the basis of the principles included in the Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, this Safety Requirements publication establishes requirements applicable to the design of nuclear power plants. It covers the design phase and provides input for the safe operation of the power plant. It elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.
Safety of Nuclear Power Plants: Design. Specific Safety Requirements (French Ed.)
International Nuclear Information System (INIS)
2012-01-01
On the basis of the principles included in the Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, this Safety Requirements publication establishes requirements applicable to the design of nuclear power plants. It covers the design phase and provides input for the safe operation of the power plant. It elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.
Safety of Nuclear Power Plants: Design. Specific Safety Requirements (Arabic Ed.)
International Nuclear Information System (INIS)
2012-01-01
On the basis of the principles included in the Fundamental Safety Principles, IAEA Safety Standards Series No. SF-1, this Safety Requirements publication establishes requirements applicable to the design of nuclear power plants. It covers the design phase and provides input for the safe operation of the power plant. It elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.
Use of a web site to enhance criticality safety training
International Nuclear Information System (INIS)
Huang, Song T.; Morman, James A.
2003-01-01
Establishment of the NCSP (Nuclear Criticality Safety Program) website represents one attempt by the NCS (Nuclear Criticality Safety) community to meet the need to enhance communication and disseminate NCS information to a wider audience. With the aging work force in this important technical field, there is a common recognition of the need to capture the corporate knowledge of these people and provide an easily accessible, web-based training opportunity to those people just entering the field of criticality safety. A multimedia-based site can provide a wide range of possibilities for criticality safety training. Training modules could range from simple text-based material, similar to the NCSET (Nuclear Criticality Safety Engineer Training) modules, to interactive web-based training classes, to video lecture series. For example, the Los Alamos National Laboratory video series of interviews with pioneers of criticality safety could easily be incorporated into training modules. Obviously, the development of such a program depends largely upon the need and participation of experts who share the same vision and enthusiasm of training the next generation of criticality safety engineers. The NCSP website is just one example of the potential benefits that web-based training can offer. You are encouraged to browse the NCSP website at http://ncsp.llnl.gov. We solicit your ideas in the training of future NCS engineers and welcome your participation with us in developing future multimedia training modules. (author)
International Nuclear Information System (INIS)
Hopper, Calvin Mitchell
2011-01-01
In May 1973 the University of New Mexico conducted the first nationwide criticality safety training and education week-long short course for nuclear criticality safety engineers. Subsequent to that course, the Los Alamos Critical Experiments Facility (LACEF) developed very successful 'hands-on' subcritical and critical training programs for operators, supervisors, and engineering staff. Since the inception of the US Department of Energy (DOE) Nuclear Criticality Technology and Safety Project (NCT and SP) in 1983, the DOE has stimulated contractor facilities and laboratories to collaborate in the furthering of nuclear criticality as a discipline. That effort included the education and training of nuclear criticality safety engineers (NCSEs). In 1985 a textbook was written that established a path toward formalizing education and training for NCSEs. Though the NCT and SP went through a brief hiatus from 1990 to 1992, other DOE-supported programs were evolving to the benefit of NCSE training and education. In 1993 the DOE established a Nuclear Criticality Safety Program (NCSP) and undertook a comprehensive development effort to expand the extant LACEF 'hands-on' course specifically for the education and training of NCSEs. That successful education and training was interrupted in 2006 for the closing of the LACEF and the accompanying movement of materials and critical experiment machines to the Nevada Test Site. Prior to that closing, the Lawrence Livermore National Laboratory (LLNL) was commissioned by the US DOE NCSP to establish an independent hands-on NCSE subcritical education and training course. The course provided an interim transition for the establishment of a reinvigorated and expanded two-week NCSE education and training program in 2011. The 2011 piloted two-week course was coordinated by the Oak Ridge National Laboratory (ORNL) and jointly conducted by the Los Alamos National Laboratory (LANL) classroom education and facility training, the Sandia National
Present status of Japanese Criticality Safety Handbook
International Nuclear Information System (INIS)
Okuno, Hiroshi
1999-01-01
A draft of the second edition of Nuclear Criticality Safety Handbook has been finalized, and it is under examination by reviewing committee for JAERI Report. Working Group designated for revising the Japanese Criticality Safety Handbook, which is chaired by Prof. Yamane, is now preparing for 'Guide on Burnup Credit for Storage and Transport of Spent Nuclear Fuel' and second edition of 'Data Collection' part of Handbook. Activities related to revising the Handbook might give a hint for a future experiment at STACY. (author)
Supplement report to the Nuclear Criticality Safety Handbook of Japan
International Nuclear Information System (INIS)
Okuno, Hiroshi; Komuro, Yuichi; Nakajima, Ken
1995-10-01
Supplementing works to 'The Nuclear Criticality Safety Handbook' of Japan have been continued since 1988, the year the handbook edited by the Science and Technology Agency first appeared. This report publishes the fruits obtained in the supplementing works. Substantial improvements are made in the chapters of 'Modelling the evaluation object' and 'Methodology for analytical safety assessment', and newly added are chapters of 'Criticality safety of chemical processes', 'Criticality accidents and their evaluation methods' and 'Basic principles on design and installation of criticality alarm system'. (author)
The International Criticality Safety Benchmark Evaluation Project (ICSBEP)
International Nuclear Information System (INIS)
Briggs, J.B.
2003-01-01
The International Criticality Safety Benchmark Evaluation Project (ICSBEP) was initiated in 1992 by the United States Department of Energy. The ICSBEP became an official activity of the Organisation for Economic Cooperation and Development (OECD) - Nuclear Energy Agency (NEA) in 1995. Representatives from the United States, United Kingdom, France, Japan, the Russian Federation, Hungary, Republic of Korea, Slovenia, Yugoslavia, Kazakhstan, Israel, Spain, and Brazil are now participating. The purpose of the ICSBEP is to identify, evaluate, verify, and formally document a comprehensive and internationally peer-reviewed set of criticality safety benchmark data. The work of the ICSBEP is published as an OECD handbook entitled 'International Handbook of Evaluated Criticality Safety Benchmark Experiments.' The 2003 Edition of the Handbook contains benchmark model specifications for 3070 critical or subcritical configurations that are intended for validating computer codes that calculate effective neutron multiplication and for testing basic nuclear data. (author)
Criticality safety and facility design considerations
International Nuclear Information System (INIS)
Waltz, W.R.
1991-06-01
Operations with fissile material introduce the risk of a criticality accident that may be lethal to nearby personnel. In addition, concerns over criticality safety can result in substantial delays and shutdown of facility operations. For these reasons, it is clear that the prevention of a nuclear criticality accident should play a major role in the design of a nuclear facility. The emphasis of this report will be placed on engineering design considerations in the prevention of criticality. The discussion will not include other important aspects, such as the physics of calculating limits nor criticality alarm systems
Criticality safety training at Westinghouse Hanford Company
International Nuclear Information System (INIS)
Rogers, C.A.; Paglieri, J.N.
1983-01-01
In 1972 the Westinghouse Hanford Company (WHC) established a comprehensive program to certify personnel who handle fissionable materials. As the quantity of fissionable material handled at WHC has increased so has the scope of training to assure that all employes perform their work in a safe manner. This paper describes training for personnel engaged in fuel fabrication and handling activities. Most of this training is provided by the Fissionable Material Handlers Certification Program. This program meets or exceeds all DOE requirements for training and has been attended by more than 475 employes. Since the program was instituted, the rate of occurrence of criticality safety limit violations has decreased by 50%
Fission, critical mass and safety-a historical review
International Nuclear Information System (INIS)
Meggitt, Geoff
2006-01-01
Since the discovery of fission, the notion of a chain reaction in a critical mass releasing massive amounts of energy has haunted physicists. The possibility of a bomb or a reactor prompted much of the early work on determining a critical mass, but the need to avoid an accidental critical excursion during processing or transport of fissile material drove much that took place subsequently. Because of the variety of possible situations that might arise, it took some time to develop adequate theoretical tools for criticality safety and the early assessments were based on direct experiment. Some extension of these experiments to closely similar situations proved possible, but it was not until the 1960s that theoretical methods (and computers to run them) developed enough for them to become reliable assessment tools. Validating such theoretical methods remained a concern, but by the end of the century they formed the backbone of criticality safety assessment. This paper traces the evolution of these methods, principally in the UK and USA, and summarises some related work concerned with the nature of criticality accidents and their radiological consequences. It also indicates how the results have been communicated and used in ensuring nuclear safety. (review)
USAEC Controls for Nuclear Criticality Safety
Energy Technology Data Exchange (ETDEWEB)
McCluggage, W. C. [Division of Operational Safety, United States Atomic Energy Commission Washington, DC (United States)
1966-05-15
This is a paper written to provide a broad general view of the United States Atomic Energy Commission's controls for nuclear criticality safety within its own facilities. Included also is a brief' discussion of the USAEC's methods of obtaining assurance that the controls are being applied. The body of the document contains three sections. The first two describe the functions of the USAEC; the third deals with the contractors. The provisions of the Atomic Energy Act applicable to health and safety are discussed in relation to nuclear criticality safety. The use of United States Atomic Energy Commission manual chapters and Federal regulations is described. The functions of the USAEC Headquarters' offices and the operations offices are briefly outlined. Comments regarding the USAEC's inspection, auditing and appraisal programmes are included. Also briefly mentioned are the basic qualifications which must be met to become a contractor to possess and process or use fissionable materials. On the plant, factory or facility level the duties and responsibilities of industrial management are briefly outlined. The fundamental standards and their origin, together with the principal documents and guides are mentioned. The chief methods of control used by contractors operating large USAEC facilities and plants are described and compared. These include diagrams of how a typical nuclear criticality safety problem is handled from inception, design, construction and finally plant operation. Also included is a brief discussion of the contractors' methods of assuring strict employee compliance with the operating rules and limits. (author)
Consensus standards utilized and implemented for nuclear criticality safety in Japan
International Nuclear Information System (INIS)
Nomura, Yasushi; Okuno, Hiroshi; Naito, Yoshitaka
1996-01-01
The fundamental framework for the criticality safety of nuclear fuel facilities regulations is, in many advanced countries, generally formulated so that technical standards or handbook data are utilized to support the licensing safety review and to implement its guidelines. In Japan also, adequacy of the safety design of nuclear fuel facilities is checked and reviewed on the basis of licensing safety review guides. These guides are, first, open-quotes The Basic Guides for Licensing Safety Review of Nuclear Fuel Facilities,close quotes and as its subsidiaries, open-quotes The Uranium Fuel Fabrication Facility Licensing Safety Review Guidesclose quotes and open-quotes The Reprocessing Facility Licensing Safety Review Guides.close quotes The open-quotes Nuclear Criticality Safety Handbook close-quote of Japan and the Technical Data Collection are published and utilized to supply related data and information for the licensing safety review, such as for the Rokkasho reprocessing plant. The well-established technical standards and data abroad such as those by the American Nuclear Society and the American National Standards Institute are also utilized to complement the standards in Japan. The basic principles of criticality safety control for nuclear fuel facilities in Japan are duly stipulated in the aforementioned basic guides as follows: 1. Guide 10: Criticality control for a single unit; 2. Guide 11: Criticality control for multiple units; 3. Guide 12: Consideration for a criticality accident
Nuclear criticality safety staff training and qualifications at Los Alamos National Laboratory
International Nuclear Information System (INIS)
Monahan, S.P.; McLaughlin, T.P.
1997-01-01
Operations involving significant quantities of fissile material have been conducted at Los Alamos National Laboratory continuously since 1943. Until the advent of the Laboratory's Nuclear Criticality Safety Committee (NCSC) in 1957, line management had sole responsibility for controlling criticality risks. From 1957 until 1961, the NCSC was the Laboratory body which promulgated policy guidance as well as some technical guidance for specific operations. In 1961 the Laboratory created the position of Nuclear Criticality Safety Office (in addition to the NCSC). In 1980, Laboratory management moved the Criticality Safety Officer (and one other LACEF staff member who, by that time, was also working nearly full-time on criticality safety issues) into the Health Division office. Later that same year the Criticality Safety Group, H-6 (at that time) was created within H-Division, and staffed by these two individuals. The training and education of these individuals in the art of criticality safety was almost entirely self-regulated, depending heavily on technical interactions between each other, as well as NCSC, LACEF, operations, other facility, and broader criticality safety community personnel. Although the Los Alamos criticality safety group has grown both in size and formality of operations since 1980, the basic philosophy that a criticality specialist must be developed through mentoring and self motivation remains the same. Formally, this philosophy has been captured in an internal policy, document ''Conduct of Business in the Nuclear Criticality Safety Group.'' There are no short cuts or substitutes in the development of a criticality safety specialist. A person must have a self-motivated personality, excellent communications skills, a thorough understanding of the principals of neutron physics, a safety-conscious and helpful attitude, a good perspective of real risk, as well as a detailed understanding of process operations and credible upsets
Proceedings of the first annual Nuclear Criticality Safety Technology Project
International Nuclear Information System (INIS)
Rutherford, D.A.
1994-09-01
This document represents the published proceedings of the first annual Nuclear Criticality Safety Technology Project (NCSTP) Workshop, which took place May 12--14, 1992, in Gaithersburg, Md. The conference consisted of four sessions, each dealing with a specific aspect of nuclear criticality safety issues. The session titles were ''Criticality Code Development, Usage, and Validation,'' ''Experimental Needs, Facilities, and Measurements,'' ''Regulation, Compliance, and Their Effects on Nuclear Criticality Technology and Safety,'' and ''The Nuclear Criticality Community Response to the USDOE Regulations and Compliance Directives.'' The conference also sponsored a Working Group session, a report of the NCSTP Working Group is also presented. Individual papers have been cataloged separately
Safety of magnetic fusion facilities: Requirements
International Nuclear Information System (INIS)
1996-05-01
This Standard identifies safety requirements for magnetic fusion facilities. Safety functions are used to define outcomes that must be achieved to ensure that exposures to radiation, hazardous materials, or other hazards are maintained within acceptable limits. Requirements applicable to magnetic fusion facilities have been derived from Federal law, policy, and other documents. In addition to specific safety requirements, broad direction is given in the form of safety principles that are to be implemented and within which safety can be achieved
IAEA safety requirements for safety assessment of fuel cycle facilities and activities
International Nuclear Information System (INIS)
Jones, G.
2013-01-01
The IAEA's Statute authorises the Agency to establish standards of safety for protection of health and minimisation of danger to life and property. In that respect, the IAEA has established a Safety Fundamentals publication which contains ten safety principles for ensuring the protection of workers, the public and the environment from the harmful effects of ionising radiation. A number of these principles require safety assessments to be carried out as a means of evaluating compliance with safety requirements for all nuclear facilities and activities and to determine the measures that need to be taken to ensure safety. The safety assessments are required to be carried out and documented by the organisation responsible for operating the facility or conducting the activity, are to be independently verified and are to be submitted to the regulatory body as part of the licensing or authorisation process. In addition to the principles of the Safety Fundamentals, the IAEA establishes requirements that must be met to ensure the protection of people and the environment and which are governed by the principles in the Safety Fundamentals. The IAEA's Safety Requirements publication 'Safety Assessment for Facilities and Activities', establishes the safety requirements that need to be fulfilled in conducting and maintaining safety assessments for the lifetime of facilities and activities, with specific attention to defence in depth and the requirement for a graded approach to the application of these safety requirements across the wide range of fuel cycle facilities and activities. Requirements for independent verification of the safety assessment that needs to be carried out by the operating organisation, including the requirement for the safety assessment to be periodically reviewed and updated are also covered. For many fuel cycle facilities and activities, environmental impact assessments and non-radiological risk assessments will be required. The
Providing Nuclear Criticality Safety Analysis Education through Benchmark Experiment Evaluation
International Nuclear Information System (INIS)
Bess, John D.; Briggs, J. Blair; Nigg, David W.
2009-01-01
One of the challenges that today's new workforce of nuclear criticality safety engineers face is the opportunity to provide assessment of nuclear systems and establish safety guidelines without having received significant experience or hands-on training prior to graduation. Participation in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and/or the International Reactor Physics Experiment Evaluation Project (IRPhEP) provides students and young professionals the opportunity to gain experience and enhance critical engineering skills.
Characterization strategy report for the criticality safety issue
International Nuclear Information System (INIS)
Doherty, A.L.; Doctor, P.G.; Felmy, A.R.; Prichard, A.W.; Serne, R.J.
1997-06-01
High-level radioactive waste from nuclear fuels processing is stored in underground waste storage tanks located in the tank farms on the Hanford Site. Waste in tank storage contains low concentrations of fissile isotopes, primarily U-235 and Pu-239. The composition and the distribution of the waste components within the storage environment is highly complex and not subject to easy investigation. An important safety concern is the preclusion of a self-sustaining neutron chain reaction, also known as a nuclear criticality. A thorough technical evaluation of processes, phenomena, and conditions is required to make sure that subcriticality will be ensured for both current and future tank operations. Subcriticality limits must be based on considerations of tank processes and take into account all chemical and geometrical phenomena that are occurring in the tanks. The important chemical and physical phenomena are those capable of influencing the mixing of fissile material and neutron absorbers such that the degree of subcriticality could be adversely impacted. This report describes a logical approach to resolving the criticality safety issues in the Hanford waste tanks. The approach uses a structured logic diagram (SLD) to identify the characterization needed to quantify risk. The scope of this section of the report is limited to those branches of logic needed to quantify the risk associated with a criticality event occurring. The process is linked to a conceptual model that depicts key modes of failure which are linked to the SLD. Data that are needed include adequate knowledge of the chemical and geometric form of the materials of interest. This information is used to determine how much energy the waste would release in the various domains of the tank, the toxicity of the region associated with a criticality event, and the probability of the initiating criticality event
Smith, David J
2010-01-01
Electrical, electronic and programmable electronic systems increasingly carry out safety functions to guard workers and the public against injury or death and the environment against pollution. The international functional safety standard IEC 61508 was revised in 2010, and this is the first comprehensive guide available to the revised standard. As functional safety is applicable to many industries, this book will have a wide readership beyond the chemical and process sector, including oil and gas, power generation, nuclear, aircraft, and automotive industries, plus project, instrumentation, design, and control engineers. * The only comprehensive guide to IEC 61508, updated to cover the 2010 amendments, that will ensure engineers are compliant with the latest process safety systems design and operation standards* Helps readers understand the process required to apply safety critical systems standards* Real-world approach helps users to interpret the standard, with case studies and best practice design examples...
Calculational study for criticality safety data of fissionable actinides
International Nuclear Information System (INIS)
Nojiri, Ichiro; Fukasaku, Yasuhiro.
1997-01-01
This study has been carried out to obtain basic criticality safety characteristics of minor actinides nuclides. Criticality safety data of minor actinides nuclides have been surveyed through public literatures. Critical mass of seven nuclides, Np-237, Am-241, Am-242m, Am-243, Cm-243, Cm-244 and Cm-245, have been calculated by using two code systems of criticality safety analysis, SCALE-4 and MCNP4A, under some material and reflector conditions. Some applicable cross-section libraries have been used for each code systems. Calculated data have been compared with each other and with published data. The results of this comparison shows that there is no discrepancy within the computational codes and the calculated data is strongly depend on the cross-section library. (author)
Safety of Nuclear Power Plants: Design. Specific Safety Requirements (Spanish Edition)
International Nuclear Information System (INIS)
2012-01-01
This publication is a revision of Safety Requirements No. NS-R-1, Safety of Nuclear Power Plants: Design. It establishes requirements applicable to the design of nuclear power plants and elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. It will be useful for organizations involved in the design, manufacture, construction, modification, maintenance, operation and decommissioning of nuclear power plants, as well as for regulatory bodies. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.
Safety of Nuclear Power Plants: Design. Specific Safety Requirements (Russian Edition)
International Nuclear Information System (INIS)
2012-01-01
This publication is a revision of Safety Requirements No. NS-R-1, Safety of Nuclear Power Plants: Design. It establishes requirements applicable to the design of nuclear power plants and elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. It will be useful for organizations involved in the design, manufacture, construction, modification, maintenance, operation and decommissioning of nuclear power plants, as well as for regulatory bodies. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.
A comparative study of formal methods for safety critical software in nuclear power plant
International Nuclear Information System (INIS)
Sohn, Se Do; Seong Poong Hyun
2000-01-01
The requirement of ultra high reliability of the safety critical software can not be demonstrated by testing alone. The specification based on formal method is recommended for safety system software. But there exist various kinds of formal methods, and this variety of formal method is recognized as an obstacle to the wide use of formal method. In this paper six different formal method have been applied to the same part of the functional requirements that is calculation algorithm intensive. The specification results were compared against the criteria that is derived from the characteristics that good software requirements specifications should have and regulatory body recommends to have. The application experience shows that the critical characteristics should be defined first, then appropriate method has to e selected. In our case, the Software Cost Reduction method was recommended for internal condition or calculation algorithm checking, and state chart method is recommended for the external behavioral description. (author)
Administrative practices for nuclear criticality safety, ANSI/ANS-8.19-1996
International Nuclear Information System (INIS)
Smith, D.R.
1996-01-01
American National Standard, open-quotes Administrative Practices for Nuclear Criticality Safety,close quotes American National Standards Institute/American Nuclear Society (ANSI/ANS)-8.19-1996, addresses the responsibilities of management, supervision, and the criticality safety staff in the administration of an effective criticality safety program. Characteristics of operating procedures, process evaluations, material control procedures, and emergency plans are discussed
Nuclear criticality safety. Chapter 0530 of AEC manual
International Nuclear Information System (INIS)
2006-01-01
The programme objectives of this chapter of the U.S. Atomic Energy Commission manual on nuclear criticality safety are to protect the health and safety of the public and of the government and contractor personnel working in plants that handle fissionable material and to protect public and private property from the consequences of a criticality accident occurring in AEC-owned plants and other AEC-contracted activities involving fissionable materials
Nuclear critical safety analysis for UX-30 transport of freight package
International Nuclear Information System (INIS)
Quan Yanhui; Zhou Qi; Yin Shenggui
2014-01-01
The nuclear critical safety analysis and evaluation for UX-30 transport freight package in the natural condition and accident condition were carried out with MONK-9A code and MCNP code. Firstly, the critical benchmark experiment data of public in international were selected, and the deflection and subcritical limiting value with MONK-9A code and MCNP code in calculating same material form were validated and confirmed. Secondly, the neutron efficiency multiplication factors in the natural condition and accident condition were calculated and analyzed, and the safety in transport process was evaluated by taking conservative suppose of nuclear critical safety. The calculation results show that the max value of k eff for UX-30 transport freight package is less than the subcritical limiting value, and the UX-30 transport freight package is in the state of subcritical safety. Moreover, the critical safety index (CSI) for UX-30 package can define zero based on the definition of critical safety index. (authors)
Safety design requirements for safety systems and components of JSFR
International Nuclear Information System (INIS)
Kubo, Shigenobu; Shimakawa, Yoshio; Yamano, Hidemasa; Kotake, Shoji
2011-01-01
Safety design requirements for JSFR were summarized taking the development targets of the FaCT project and design feature of JSFR into account. The related safety principle and requirements for Monju, CRBRP, PRISM, SPX, LWRs, IAEA standards, goals of GIF, basic principle of INPRO etc. were also taken into account so that the safety design requirements can be a next-generation global standard. The development targets for safety and reliability are set based on those of FaCT, namely, ensuring safety and reliability equal to future LWR and related fuel cycle facilities. In order to achieve these targets, the defence-in-depth concept is used as the basic safety design principle. General features of the safety design requirements are 1) Achievement of higher reliability, 2) Achievement of higher inspectability and maintainability, 3) Introduction of passive safety features, 4) Reduction of operator action needs, 5) Design consideration against Beyond Design Basis Events, 6) In-Vessel Retention of degraded core materials, 7) Prevention and mitigation against sodium chemical reactions, and 8) Design against external events. The current specific requirements for each system and component are summarized taking the basic design concept of JSFR into account, which is an advanced loop-type large-output power plant with a mixed-oxide-fuelled core. (author)
Criticality safety engineer training at WSRC
International Nuclear Information System (INIS)
Williamson, T.G.; Mincey, J.F.
1993-01-01
Two programs designed to prepare engineers for certification as criticality safety engineers are offered at Westinghouse Savannah River Company (WSRC). One program, Student On Loan Criticality Engineer Training (SOLCET), is an intensive 2-yr course involving lectures, rigorous problem assignments, and mentoring. The other program, In-Field Criticality Engineer Training (IN-FIELD), is a less intensive series of lectures and problem assignments. Both courses are conducted by members of the Applied Physics Group (APG) of the Savannah River Technical Center, the organization at WSRC responsible for the operation and maintenance of criticality codes and for training of code users
Criticality Safety Basics for INL Emergency Responders
Energy Technology Data Exchange (ETDEWEB)
Valerie L. Putman
2012-08-01
This document is a modular self-study guide about criticality safety principles for Idaho National Laboratory emergency responders. This guide provides basic criticality safety information for people who, in response to an emergency, might enter an area that contains much fissionable (or fissile) material. The information should help responders understand unique factors that might be important in responding to a criticality accident or in preventing a criticality accident while responding to a different emergency.
This study guide specifically supplements web-based training for firefighters (0INL1226) and includes information for other Idaho National Laboratory first responders. However, the guide audience also includes other first responders such as radiological control personnel.
For interested readers, this guide includes clearly marked additional information that will not be included on tests. The additional information includes historical examples (Been there. Done that.), as well as facts and more in-depth information (Did you know …).
INL criticality safety personnel revise this guide as needed to reflect program changes, user requests, and better information. Revision 0, issued May 2007, established the basic text. Revision 1 incorporates operation, program, and training changes implemented since 2007. Revision 1 increases focus on first responders because later responders are more likely to have more assistance and guidance from facility personnel and subject matter experts. Revision 1 also completely reorganized the training to better emphasize physical concepts behind the criticality controls that help keep emergency responders safe. The changes are based on and consistent with changes made to course 0INL1226.
Nuclear Criticality Technology and Safety Project parameter study database
International Nuclear Information System (INIS)
Toffer, H.; Erickson, D.G.; Samuel, T.J.; Pearson, J.S.
1993-03-01
A computerized, knowledge-screened, comprehensive database of the nuclear criticality safety documentation has been assembled as part of the Nuclear Criticality Technology and Safety (NCTS) Project. The database is focused on nuclear criticality parameter studies. The database has been computerized using dBASE III Plus and can be used on a personal computer or a workstation. More than 1300 documents have been reviewed by nuclear criticality specialists over the last 5 years to produce over 800 database entries. Nuclear criticality specialists will be able to access the database and retrieve information about topical parameter studies, authors, and chronology. The database places the accumulated knowledge in the nuclear criticality area over the last 50 years at the fingertips of a criticality analyst
International Nuclear Information System (INIS)
Williams, R.A.
1995-01-01
The Columbia Fuel Fabrication Facility of the Westinghouse Commercial Nuclear Fuel Division manufactures low-enriched uranium fuel and associated components for use in commercial pressurized water power reactors. To support development of a comprehensive integrated safety assessment (ISA) for the facility, as well as to address increasing U.S. Nuclear Regulatory Commission (NRC) expectations regarding such a facility's criticality safety assessments, a project is under way to complete criticality safety evaluations (CSEs) of all plant systems used in processing nuclear materials. Each CSE is made up of seven sections, prepared by a multidisciplinary team of process engineers, systems engineers, safety engineers, maintenance representatives, and operators. This paper provides a cursory outline of the type of information presented in a CSE
An evaluation of safety-critical Java on a Java processor
Rios Rivas, Juan Ricardo; Schoeberl, Martin
2014-01-01
The safety-critical Java (SCJ) specification provides a restricted set of the Java language intended for applications that require certification. In order to test the specification, implementations are emerging and the need to evaluate those implementations in a systematic way is becoming important. In this paper we evaluate our SCJ implementation which is based on the Java Optimized Processor JOP and we measure different performance and timeliness criteria relevant to hard real-time systems....
How to interpret safety critical failures in risk and reliability assessments
International Nuclear Information System (INIS)
Selvik, Jon Tømmerås; Signoret, Jean-Pierre
2017-01-01
Management of safety systems often receives high attention due to the potential for industrial accidents. In risk and reliability literature concerning such systems, and particularly concerning safety-instrumented systems, one frequently comes across the term ‘safety critical failure’. It is a term associated with the term ‘critical failure’, and it is often deduced that a safety critical failure refers to a failure occurring in a safety critical system. Although this is correct in some situations, it is not matching with for example the mathematical definition given in ISO/TR 12489:2013 on reliability modeling, where a clear distinction is made between ‘safe failures’ and ‘dangerous failures’. In this article, we show that different interpretations of the term ‘safety critical failure’ exist, and there is room for misinterpretations and misunderstandings regarding risk and reliability assessments where failure information linked to safety systems are used, and which could influence decision-making. The article gives some examples from the oil and gas industry, showing different possible interpretations of the term. In particular we discuss the link between criticality and failure. The article points in general to the importance of adequate risk communication when using the term, and gives some clarification on interpretation in risk and reliability assessments.
Safety of Nuclear Power Plants: Commissioning and Operation. Specific Safety Requirements
International Nuclear Information System (INIS)
2016-01-01
This publication describes the requirements to be met to ensure the safe operation of nuclear power plants. It takes into account developments in areas such as long term operation of nuclear power plants, plant ageing, periodic safety review, probabilistic safety analysis and risk informed decision making processes. In addition, the requirements are governed by, and must apply, the safety objective and safety principles that are established in the IAEA Safety Standards Series No. SF-1, Fundamental Safety Principles. A review of Safety Requirements publications was commenced in 2011 following the accident in the Fukushima Daiichi nuclear power plant in Japan. The review revealed no significant areas of weakness and resulted in just a small set of amendments to strengthen the requirements and facilitate their implementation, which are contained in the present publication
Software for safety critical applications
International Nuclear Information System (INIS)
Kropik, M.; Matejka, K.; Jurickova, M.; Chudy, R.
2001-01-01
The contribution gives an overview of the project of the software development for safety critical applications. This project has been carried out since 1997. The principal goal of the project was to establish a research laboratory for the development of the software with the highest requirements for quality and reliability. This laboratory was established at the department, equipped with proper hardware and software to support software development. A research team of predominantly young researchers for software development was created. The activities of the research team started with studying and proposing the software development methodology. In addition, this methodology was applied to the real software development. The verification and validation process followed the software development. The validation system for the integrated hardware and software tests was brought into being and its control software was developed. The quality of the software tools was also observed, and the SOSAT tool was used during these activities. National and international contacts were established and maintained during the project solution.(author)
International Nuclear Information System (INIS)
White, W.F.
1997-01-01
The Criticality Alarm System (CAS) provides continuous detection for high radiation (criticality) events and automatically initiates an evacuation signal to affected personnel. The Safety Envelope (SE) for PFP includes the necessary equipment and the required procedures to ensure the CAS is capable of performing its intended function. This document provides the definition and means of maintaining the SE for PFP related to the CAS. This document also identifies and provides a justification for those portions of the CAS excluded from the PFP Safety Envelope
Preparation for the second edition of nuclear criticality safety handbook
International Nuclear Information System (INIS)
Okuno, Hiroshi; Nomura, Yasushi
1997-01-01
The making of the second edition of Nuclear Criticality Safety Handbook entered the final stage of investigation by the working group. In the second edition, the newest results of the researches in Japan were taken. In this report, among the subjects which were examined continuously from the first edition published in 1988, the size of fuel particles which can be regarded as homogeneous even in a heterogeneous system, the reactivity effect when fuel concentration distribution became not uniform in a homogeneous fuel system, the method of evaluating criticality safety in which submersion is not assumed, and the criticality data when fuel burning is considered are explained. Further, about the matters related to the criticality in chemical processes and the matters related to criticality accident, the outlines are introduced. Finally, the state of preparation for aiming at the third edition is mentioned. Criticality safety control is important for overall nuclear fuel cycle including the transportation and storage of fuel. The course of the publication of this Handbook is outlined. The matters which have been successively examined from the first edition, the results of criticality safety analysis for the dissolving tanks of fuel reprocessing, and the analysis code and the simplified evaluation method for criticality accident are reported. (K.I.)
Safety culture and subcontractor network governance in a complex safety critical project
International Nuclear Information System (INIS)
Oedewald, Pia; Gotcheva, Nadezhda
2015-01-01
In safety critical industries many activities are currently carried out by subcontractor networks. Nevertheless, there are few studies where the core dimensions of resilience would have been studied in safety critical network activities. This paper claims that engineering resilience into a system is largely about steering the development of culture of the system towards better ability to anticipate, monitor, respond and learn. Thus, safety culture literature has relevance in resilience engineering field. This paper analyzes practical and theoretical challenges in applying the concept of safety culture in a complex, dynamic network of subcontractors involved in the construction of a new nuclear power plant in Finland, Olkiluoto 3. The concept of safety culture is in focus since it is widely used in nuclear industry and bridges the scientific and practical interests. This paper approaches subcontractor networks as complex systems. However, the management model of the Olkiluoto 3 project is to a large degree a traditional top-down hierarchy, which creates a mismatch between the management approach and the characteristics of the system to be managed. New insights were drawn from network governance studies. - Highlights: • We studied a relevant topical subject safety culture in nuclear new build project. • We integrated safety science challenges and network governance studies. • We produced practicable insights in managing safety of subcontractor networks
Safety of Nuclear Power Plants: Commissioning and Operation. Specific Safety Requirements
International Nuclear Information System (INIS)
2017-01-01
This publication is a revision of IAEA Safety Standards Series No. NS-R-2, Safety of Nuclear Power Plants: Operation, and has been extended to cover the commissioning stage. It describes the requirements to be met to ensure the safe commissioning, operation, and transition from operation to decommissioning of nuclear power plants. Over recent years there have been developments in areas such as long term operation of nuclear power plants, plant ageing, periodic safety review, probabilistic safety analysis review and risk informed decision making processes. It became necessary to revise the IAEA’s Safety Requirements in these areas and to correct and/or improve the publication on the basis of feedback from its application by both the IAEA and its Member States. In addition, the requirements are governed by, and must apply, the safety objective and safety principles that are established in the IAEA Safety Standards Series No. SF-1, Fundamental Safety Principles. A review of Safety Requirements publications, initiated in 2011 following the accident in the Fukushima Daiichi nuclear power plant in Japan, revealed no significant areas of weakness but resulted in a small set of amendments to strengthen the requirements and facilitate their implementation. These are contained in the present publication.
Criticality safety benchmark evaluation project: Recovering the past
Energy Technology Data Exchange (ETDEWEB)
Trumble, E.F.
1997-06-01
A very brief summary of the Criticality Safety Benchmark Evaluation Project of the Westinghouse Savannah River Company is provided in this paper. The purpose of the project is to provide a source of evaluated criticality safety experiments in an easily usable format. Another project goal is to search for any experiments that may have been lost or contain discrepancies, and to determine if they can be used. Results of evaluated experiments are being published as US DOE handbooks.
The Criticality Safety Information Resource Center (CSIRC) at Los Alamos National Laboratory
International Nuclear Information System (INIS)
Henderson, B.D.; Meade, R.A.; Pruvost, N.L.
1999-01-01
The Criticality Safety Information Resource Center (CSIRC) at Los Alamos National Laboratory (LANL) is a program jointly funded by the U.S. Department of Energy (DOE) and the U.S. Nuclear Regulatory Commission (NRC) in conjunction with the Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 97-2. The goal of CSIRC is to preserve primary criticality safety documentation from U.S. critical experimental sites and to make this information available for the benefit of the technical community. Progress in archiving criticality safety primary documents at the LANL archives as well as efforts to make this information available to researchers are discussed. The CSIRC project has a natural linkage to the International Criticality Safety Benchmark Evaluation Project (ICSBEP). This paper raises the possibility that the CSIRC project will evolve in a fashion similar to the ICSBEP. Exploring the implications of linking the CSIRC to the international criticality safety community is the motivation for this paper
CSER 98-003: criticality safety evaluation report for PFP glovebox HC-21A with button can opening
International Nuclear Information System (INIS)
ERICKSON, D.G.
1999-01-01
Glovebox HC-21A is an enclosure where cans containing plutonium metal buttons or other plutonium bearing materials are prepared for thermal stabilization in the muffle furnaces. The Inert Atmosphere Confinement (IAC), a new feature added to Glovebox HC-21 A, allows the opening of containers suspected of containing hydrided plutonium metal. The argon atmosphere in the IAC prevents an adverse reaction between oxygen and the hydride. The hydride is then stabilized in a controlled manner to prevent glovebox over pressurization. After removal from the containers, the plutonium metal buttons or plutonium bearing materials will be placed into muffle furnace boats and then be sent to one of the muffle furnace gloveboxes for stabilization. The materials allowed to be brought into Glovebox HC-21A are limited to those with a hydrogen to fissile atom ratio (H/X) ≤ 20. Glovebox HC-21A is classified as a DRY glovebox, meaning it has no internal liquid lines, and no free liquids or solutions are allowed to be introduced. The double contingency principle states that designs shall incorporate sufficient factors of safety to require at least two unlikely, independent, and concurrent changes in process conditions before a criticality accident is possible. This criticality safety evaluation report (CSER) shows that the operations to be performed in this glovebox are safe from a criticality standpoint. No single identified event that causes criticality controls to be lost exceeded the criticality safety limit of k eff = 0.95 (including uncertainties). Therefore, this CSER meets the requirements for a criticality analysis contained in the Hanford Site Nuclear Criticality Safety Manual, HNF-PRO-334, and meets the double contingency principle
CSER 98-003: Criticality safety evaluation report for PFP glovebox HC-21A with button can opening
International Nuclear Information System (INIS)
ERICKSON, D.G.
1999-01-01
Glovebox HC-21A is an enclosure where cans containing plutonium metal buttons or other plutonium bearing materials are prepared for thermal stabilization in the muffle furnaces. The Inert Atmosphere Confinement (IAC), a new feature added to Glovebox HC-21A, allows the opening of containers suspected of containing hydrided plutonium metal. The argon atmosphere in the IAC prevents an adverse reaction between oxygen and the hydride. The hydride is then stabilized in a controlled manner to prevent glovebox over pressurization. After removal from the containers, the plutonium metal buttons or plutonium bearing materials will be placed into muffle furnace boats and then be sent to one of the muffle furnace gloveboxes for stabilization. The materials allowed to be brought into GloveboxHC-21 A are limited to those with a hydrogen to fissile atom ratio (H/X) ≤ 20. Glovebox HC-21A is classified as a DRY glovebox, meaning it has no internal liquid lines, and no free liquids or solutions are allowed to be introduced. The double contingency principle states that designs shall incorporate sufficient factors of safety to require at least two unlikely, independent, and concurrent changes in process conditions before a criticality accident is possible. This criticality safety evaluation report (CSER) shows that the operations to be performed in this glovebox are safe from a criticality standpoint. No single identified event that causes criticality controls to be lost exceeded the criticality safety limit of k eff = 0.95. Therefore, this CSER meets the requirements for a criticality analysis contained in the Hanford Site Nuclear Criticality Safety Manual, HNF-PRO-334, and meets the double contingency principle
Recommendations relating to safety-critical real-time software in nuclear power plants
International Nuclear Information System (INIS)
1992-01-01
The Advisory Committee on Nuclear Safety (ACNS) has reviewed safety issues associated with the software for the digital computers in the safety shutdown systems for the Darlington NGS. From this review the ACNS has developed four recommendations for safety-critical real-time software in nuclear power plants. These recommendations cover: the completion of the present efforts to develop an overall standard and sub-tier standards for safety-critical real-time software; the preparation of schedules and lists of responsibilities for this development; the concentration of AECB efforts on ensuring the scrutability of safety-critical real-time software; and, the collection of data on reliability and causes of failure (error) of safety-critical real-time software systems and on the probability and causes of common-mode failures (errors). (9 refs.)
Tank waste remediation system nuclear criticality safety program management review
International Nuclear Information System (INIS)
BRADY RAAP, M.C.
1999-01-01
This document provides the results of an internal management review of the Tank Waste Remediation System (TWRS) criticality safety program, performed in advance of the DOE/RL assessment for closure of the TWRS Nuclear Criticality Safety Issue, March 1994. Resolution of the safety issue was identified as Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-40-12, due September 1999
Agility in Development of Safety-Critical Software: A Conceptual Model
DEFF Research Database (Denmark)
Tordrup Heeager, Lise; Nielsen, Peter Axel
2018-01-01
Safety-critical information systems are being used increasingly as we see applications in new areas such as personal medical devices, traffic control and detection of pathogens. A current research debate is whether safety-critical systems must be developed with traditional waterfall processes...
Site evaluation for nuclear installations. Safety requirements
International Nuclear Information System (INIS)
2003-01-01
This Safety Requirements publication supersedes the Code on the Safety of Nuclear Power Plants: Siting, which was issued in 1988 as Safety Series No. 50-C-S (Rev. 1). It takes account of developments relating to site evaluations for nuclear installations since the Code on Siting was last revised. These developments include the issuing of the Safety Fundamentals publication on The Safety of Nuclear Installations, and the revision of various safety standards and other publications relating to safety. Requirements for site evaluation are intended to ensure adequate protection of site personnel, the public and the environment from the effects of ionizing radiation arising from nuclear installations. It is recognized that there are steady advances in technology and scientific knowledge, in nuclear safety and in what is considered adequate protection. Safety requirements change with these advances and this publication reflects the present consensus among States. This Safety Requirements publication was prepared under the IAEA programme on safety standards for nuclear installations. It establishes requirements and provides criteria for ensuring safety in site evaluation for nuclear installations. The Safety Guides on site evaluation listed in the references provide recommendations on how to meet the requirements established in this Safety Requirements publication. The objective of this publication is to establish the requirements for the elements of a site evaluation for a nuclear installation so as to characterize fully the site specific conditions pertinent to the safety of a nuclear installation. The purpose is to establish requirements for criteria, to be applied as appropriate to site and site-installation interaction in operational states and accident conditions, including those that could lead to emergency measures for: (a) Defining the extent of information on a proposed site to be presented by the applicant; (b) Evaluating a proposed site to ensure that the site
International Nuclear Information System (INIS)
WITTEKIND, W.D.
2001-01-01
This analysis meets the requirements of HNF-7098, Criticality Safety Program, (FH 2001a). HNF-7098 states that before starting a new operation with fissile material or before an existing operation is changed, it shall be determined that the entire process will be subcritical under both normal and credible abnormal conditions. To demonstrate the Incredibility Principle is satisfied, this Criticality Safety Evaluation Report (CSER) shows that the form or distribution is such that criticality is impossible. This evaluation demonstrated, that on the basis of effective 235 U enrichment, criticality is not possible. The minimum blanket assembly exposure is 4,375 MW t d/MTU for fissile material that is shown to fulfill the Incredibility Principle safety criterion on the basis of enrichment
Criticality safety analysis of spent fuel storage for NPP Mochovce using MCNP5
International Nuclear Information System (INIS)
Farkas, G.; Hascik, J.; Lueley, J.; Vrban, B.; Petriska, M.; Slugen, V.; Urban, P.
2011-01-01
The paper presents results of nuclear criticality safety analysis of spent fuel storage for the first and second unit of NPP Mochovce. The spent fuel storage pool (compact and reserve grid) was modeled using the Monte Carlo code MCNP5. Conservative approach was applied and calculation of k eff values was performed for normal and various postulated emergency conditions in order to evaluate the final maximal k eff values. The requirement of current safety regulations to ensure 5% subcriticality was met except one especially conservative case. (Authors)
Range Flight Safety Requirements
Loftin, Charles E.; Hudson, Sandra M.
2018-01-01
The purpose of this NASA Technical Standard is to provide the technical requirements for the NPR 8715.5, Range Flight Safety Program, in regards to protection of the public, the NASA workforce, and property as it pertains to risk analysis, Flight Safety Systems (FSS), and range flight operations. This standard is approved for use by NASA Headquarters and NASA Centers, including Component Facilities and Technical and Service Support Centers, and may be cited in contract, program, and other Agency documents as a technical requirement. This standard may also apply to the Jet Propulsion Laboratory or to other contractors, grant recipients, or parties to agreements to the extent specified or referenced in their contracts, grants, or agreements, when these organizations conduct or participate in missions that involve range flight operations as defined by NPR 8715.5.1.2.2 In this standard, all mandatory actions (i.e., requirements) are denoted by statements containing the term “shall.”1.3 TailoringTailoring of this standard for application to a specific program or project shall be formally documented as part of program or project requirements and approved by the responsible Technical Authority in accordance with NPR 8715.3, NASA General Safety Program Requirements.
Energy Technology Data Exchange (ETDEWEB)
Williams, R.A. [Westinghouse Electric Corp., Columbia, SC (United States)
1995-12-31
The Columbia Fuel Fabrication Facility of the Westinghouse Commercial Nuclear Fuel Division manufactures low-enriched uranium fuel and associated components for use in commercial pressurized water power reactors. To support development of a comprehensive integrated safety assessment (ISA) for the facility, as well as to address increasing U.S. Nuclear Regulatory Commission (NRC) expectations regarding such a facility`s criticality safety assessments, a project is under way to complete criticality safety evaluations (CSEs) of all plant systems used in processing nuclear materials. Each CSE is made up of seven sections, prepared by a multidisciplinary team of process engineers, systems engineers, safety engineers, maintenance representatives, and operators. This paper provides a cursory outline of the type of information presented in a CSE.
Disposal of Radioactive Waste. Specific Safety Requirements
International Nuclear Information System (INIS)
2011-01-01
This publication establishes requirements applicable to all types of radioactive waste disposal facility. It is linked to the fundamental safety principles for each disposal option and establishes a set of strategic requirements that must be in place before facilities are developed. Consideration is also given to the safety of existing facilities developed prior to the establishment of present day standards. The requirements will be complemented by Safety Guides that will provide guidance on good practice for meeting the requirements for different types of waste disposal facility. Contents: 1. Introduction; 2. Protection of people and the environment; 3. Safety requirements for planning for the disposal of radioactive waste; 4. Requirements for the development, operation and closure of a disposal facility; 5. Assurance of safety; 6. Existing disposal facilities; Appendices.
Criticality Safety Support to a Project Addressing SNM Legacy Items at LLNL
International Nuclear Information System (INIS)
Pearson, J S; Burch, J G; Dodson, K E; Huang, S T
2005-01-01
The programmatic, facility and criticality safety support staffs at the LLNL Plutonium Facility worked together to successfully develop and implement a project to process legacy (DNFSB Recommendation 94-1 and non-Environmental, Safety, and Health (ES and H) labeled) materials in storage. Over many years, material had accumulated in storage that lacked information to adequately characterize the material for current criticality safety controls used in the facility. Generally, the fissionable material mass information was well known, but other information such as form, impurities, internal packaging, and presence of internal moderating or reflecting materials were not well documented. In many cases, the material was excess to programmatic need, but such a determination was difficult with the little information given on MC and A labels and in the MC and A database. The material was not packaged as efficiently as possible, so it also occupied much more valuable storage space than was necessary. Although safe as stored, the inadequately characterized material posed a risk for criticality safety noncompliances if moved within the facility under current criticality safety controls. A Legacy Item Implementation Plan was developed and implemented to deal with this problem. Reasonable bounding conditions were determined for the material involved, and criticality safety evaluations were completed. Two appropriately designated glove boxes were identified and criticality safety controls were developed to safely inspect the material. Inspecting the material involved identifying containers of legacy material, followed by opening, evaluating, processing if necessary, characterizing and repackaging the material. Material from multiple containers was consolidated more efficiently thus decreasing the total number of stored items to about one half of the highest count. Current packaging requirements were implemented. Detailed characterization of the material was captured in databases
Applications of PRA in nuclear criticality safety
International Nuclear Information System (INIS)
McLaughlin, T.P.
1992-01-01
Traditionally, criticality accident prevention at Los Alamos National Laboratory (LANL) has been based on a thorough review and understanding of proposed operations or changes to operations involving both process supervision and criticality safety staff. The outcome of this communication was usually an agreement, based on professional judgment, that certain accident sequences were credible and had to be precluded by design; others were incredible and thus did not warrant expenditures to further reduce their likelihood. The extent of documentation was generally in proportion to the complexity of the operation but never as detailed as that associated with quantified risk assessments. During the last 3 yr, nuclear criticality safety-related probabilistic risk assessments (PRAs) have been performed on operations in two LANL facilities. Both of these were conducted in order to better understand the cost/benefit aspects of PRAs as they apply to largely hands-on operations with fissile material
Computational methods for criticality safety analysis within the scale system
International Nuclear Information System (INIS)
Parks, C.V.; Petrie, L.M.; Landers, N.F.; Bucholz, J.A.
1986-01-01
The criticality safety analysis capabilities within the SCALE system are centered around the Monte Carlo codes KENO IV and KENO V.a, which are both included in SCALE as functional modules. The XSDRNPM-S module is also an important tool within SCALE for obtaining multiplication factors for one-dimensional system models. This paper reviews the features and modeling capabilities of these codes along with their implementation within the Criticality Safety Analysis Sequences (CSAS) of SCALE. The CSAS modules provide automated cross-section processing and user-friendly input that allow criticality safety analyses to be done in an efficient and accurate manner. 14 refs., 2 figs., 3 tabs
Method of V ampersand V for safety-critical software in NPPs
International Nuclear Information System (INIS)
Kim, Jang-Yeol; Lee, Jang-Soo; Kwon, Kee-Choon
1997-01-01
Safety-critical software is software used in systems in which a failure could affect personal or equipment safety or result in large financial or social loss. Examples of systems using safety-critical software are systems such as plant protection systems in nuclear power plants (NPPs), process control systems in chemical plants, and medical instruments such as the Therac-25 medical accelerator. This paper presents verification and validation (V ampersand V) methodology for safety-critical software in NPP safety systems. In addition, it addresses issues related to NPP safety systems, such as independence parameters, software safety analysis (SSA) concepts, commercial off-the-shelf (COTS) software evaluation criteria, and interrelationships among software and system assurance organizations. It includes the concepts of existing industrial standards on software V ampersand V, Institute of Electrical and Electronics Engineers (IEEE) Standards 1012 and 1059. This safety-critical software V ampersand V methodology covers V ampersand V scope, a regulatory framework as part of its acceptance criteria, V ampersand V activities and task entrance and exit criteria, reviews and audits, testing and quality assurance records of V ampersand V material, configuration management activities related to V ampersand V, and software V ampersand V (SVV) plan (SVVP) production
Torres-Pomales, Wilfredo
2014-01-01
A system is safety-critical if its failure can endanger human life or cause significant damage to property or the environment. State-of-the-art computer systems on commercial aircraft are highly complex, software-intensive, functionally integrated, and network-centric systems of systems. Ensuring that such systems are safe and comply with existing safety regulations is costly and time-consuming as the level of rigor in the development process, especially the validation and verification activities, is determined by considerations of system complexity and safety criticality. A significant degree of care and deep insight into the operational principles of these systems is required to ensure adequate coverage of all design implications relevant to system safety. Model-based development methodologies, methods, tools, and techniques facilitate collaboration and enable the use of common design artifacts among groups dealing with different aspects of the development of a system. This paper examines the application of model-based development to complex and safety-critical aircraft computer systems. Benefits and detriments are identified and an overall assessment of the approach is given.
Criticality safety analysis of Hanford Waste Tank 241-101-SY
International Nuclear Information System (INIS)
Perry, R.T.; Sapir, J.L.; Krohn, B.J.
1993-01-01
As part of a safety assessment for proposed pump mixing operations to mitigate episodic gas releases in Tank 241-101-SY at the Hanford Site, Richland, Washington, a criticality safety analysis was made using the Sn transport code ONEDANT. The tank contains approximately one million gallons of waste and an estimated 910 G of plutonium. the criticality analysis considers reconfiguration and underestimation of plutonium content. The results indicate that Tank SY-101 does not present a criticality hazard. These methods are also used in criticality analyses of other Hanford tanks
Criticality safety evaluation report for FFTF 42% fuel assemblies
International Nuclear Information System (INIS)
Richard, R.F.
1997-01-01
An FFTF tritium/isotope production mission will require a new fuel supply. The reference design core will use a mixed oxide fuel nominally enriched to 40 wt% Pu. This enrichment is significantly higher than that of the standard Driver Fuel Assemblies used in past operations. Consequently, criticality safety for handling and storage of this fuel must be addressed. The purpose of this document is to begin the process by determining the minimum critical number for these new fuel assemblies in water, sodium and air. This analysis is preliminary and further work can be done to refine the results reported here. Analysis was initially done using 45 wt 5 PuO. Additionally, a preliminary assessment is done concerning storage of these fuel assemblies in Interim Decay Storage (IDS), Fuel Storage Facility (FSF), and Core Component Containers/Interim Storage Casks (CCC/ISC)
Developing guidance in the nuclear criticality safety assessment for fuel cycle facilities
International Nuclear Information System (INIS)
Galet, C.; Evo, S.
2012-01-01
In this poster IRSN (Institute for radiation protection and nuclear safety) presents its safety guides whose purpose is to transmit the safety assessment know-how to any 'junior' staff or even to give a view of the safety approach on the overall risks to any staff member. IRSN has written a first version of such a safety guide for fuel cycle facilities and laboratories. It is organized into several chapters: some refer to types of assessments, others concern the types of risks. Currently, this guide contains 13 chapters and each chapter consists of three parts. In parallel to the development of criticality chapter of this guide, the IRSN criticality department has developed a nuclear criticality safety guide. It follows the structure of the three parts fore-mentioned, but it presents a more detailed first part and integrates, in the third part, the experience feedback collected on nuclear facilities. The nuclear criticality safety guide is online on the IRSN's web site
Research on neutron source multiplication method in nuclear critical safety
International Nuclear Information System (INIS)
Zhu Qingfu; Shi Yongqian; Hu Dingsheng
2005-01-01
The paper concerns in the neutron source multiplication method research in nuclear critical safety. Based on the neutron diffusion equation with external neutron source the effective sub-critical multiplication factor k s is deduced, and k s is different to the effective neutron multiplication factor k eff in the case of sub-critical system with external neutron source. The verification experiment on the sub-critical system indicates that the parameter measured with neutron source multiplication method is k s , and k s is related to the external neutron source position in sub-critical system and external neutron source spectrum. The relation between k s and k eff and the effect of them on nuclear critical safety is discussed. (author)
Leadership and Management for Safety. General Safety Requirements (Arabic Edition)
International Nuclear Information System (INIS)
2016-01-01
This Safety Requirements publication establishes requirements that support Principle 3 of the Fundamental Safety Principles in relation to establishing, sustaining and continuously improving leadership and management for safety and an integrated management system. It emphasizes that leadership for safety, management for safety, an effective management system and a systemic approach (i.e. an approach in which interactions between technical, human and organizational factors are duly considered) are all essential to the specification and application of adequate safety measures and to the fostering of a strong safety culture. Leadership and an effective management system will integrate safety, health, environmental, security, quality, human-and-organizational factors, societal and economic elements. The management system will ensure the fostering of a strong safety culture, regular assessment of performance and the application of lessons from experience. The publication is intended for use by regulatory bodies, operating organizations and other organizations concerned with facilities and activities that give rise to radiation risks.
Leadership and Management for Safety. General Safety Requirements (Chinese Edition)
International Nuclear Information System (INIS)
2016-01-01
This Safety Requirements publication establishes requirements that support Principle 3 of the Fundamental Safety Principles in relation to establishing, sustaining and continuously improving leadership and management for safety and an integrated management system. It emphasizes that leadership for safety, management for safety, an effective management system and a systemic approach (i.e. an approach in which interactions between technical, human and organizational factors are duly considered) are all essential to the specification and application of adequate safety measures and to the fostering of a strong safety culture. Leadership and an effective management system will integrate safety, health, environmental, security, quality, human-and-organizational factors, societal and economic elements. The management system will ensure the fostering of a strong safety culture, regular assessment of performance and the application of lessons from experience. The publication is intended for use by regulatory bodies, operating organizations and other organizations concerned with facilities and activities that give rise to radiation risks.
Leadership and Management for Safety. General Safety Requirements (French Edition)
International Nuclear Information System (INIS)
2016-01-01
This Safety Requirements publication establishes requirements that support Principle 3 of the Fundamental Safety Principles in relation to establishing, sustaining and continuously improving leadership and management for safety and an integrated management system. It emphasizes that leadership for safety, management for safety, an effective management system and a systemic approach (i.e. an approach in which interactions between technical, human and organizational factors are duly considered) are all essential to the specification and application of adequate safety measures and to the fostering of a strong safety culture. Leadership and an effective management system will integrate safety, health, environmental, security, quality, human-and-organizational factors, societal and economic elements. The management system will ensure the fostering of a strong safety culture, regular assessment of performance and the application of lessons from experience. The publication is intended for use by regulatory bodies, operating organizations and other organizations concerned with facilities and activities that give rise to radiation risks.
Leadership and Management for Safety. General Safety Requirements (Spanish Edition)
International Nuclear Information System (INIS)
2017-01-01
his Safety Requirements publication establishes requirements that support Principle 3 of the Fundamental Safety Principles in relation to establishing, sustaining and continuously improving leadership and management for safety and an integrated management system. It emphasizes that leadership for safety, management for safety, an effective management system and a systemic approach (i.e. an approach in which interactions between technical, human and organizational factors are duly considered) are all essential to the specification and application of adequate safety measures and to the fostering of a strong safety culture. Leadership and an effective management system will integrate safety, health, environmental, security, quality, human-and-organizational factors, societal and economic elements. The management system will ensure the fostering of a strong safety culture, regular assessment of performance and the application of lessons from experience. The publication is intended for use by regulatory bodies, operating organizations and other organizations concerned with facilities and activities that give rise to radiation risks.
International Nuclear Information System (INIS)
Koh, Kwang Yong; Seong, Poong Hyun
2005-01-01
Safety-critical software process is composed of development process, verification and validation (V and V) process and safety analysis process. Safety analysis process has been often treated as an additional process and not found in a conventional software process. But software safety analysis (SSA) is required if software is applied to a safety system, and the SSA shall be performed independently for the safety software through software development life cycle (SDLC). Of all the phases in software development, requirements engineering is generally considered to play the most critical role in determining the overall software quality. NASA data demonstrate that nearly 75% of failures found in operational software were caused by errors in the requirements. The verification process in requirements phase checks the correctness of software requirements specification, and the safety analysis process analyzes the safety-related properties in detail. In this paper, the method for safety analysis at requirements phase of software development life cycle using symbolic model verifier (SMV) is proposed. Hazard is discovered by hazard analysis and in other to use SMV for the safety analysis, the safety-related properties are expressed by computation tree logic (CTL)
Criticality safety training at the Hot Fuel Examination Facility
International Nuclear Information System (INIS)
Garcia, A.S.; Courtney, J.C.; Thelen, V.N.
1983-01-01
HFEF comprises four hot cells and out-of-cell support facilities for the US breeder program. The HFEF criticality safety program includes training in the basic theory of criticality and in specific criticality hazard control rules that apply to HFEF. A professional staff-member oversees the implementation of the criticality prevention program
International Nuclear Information System (INIS)
Kwon, K. C.; Park, G. Y.
2006-01-01
This paper describes the Verification and Validation (V and V) activities for the safety-critical software in a Digital Reactor Protection System (DRPS) that is being developed through the Korea nuclear instrumentation and control system project. The main activities of the DRPS V and V process are a preparation of the software planning documentation, a verification of the software according to the software life cycle, a software safety analysis and a software configuration management. The verification works for the Software Requirement Specification (SRS) of the DRPS consist of a technical evaluation, a licensing suitability evaluation, a inspection and traceability analysis, a formal verification, and preparing a test plan and procedure. Especially, the SRS is specified by the formal specification method in the development phase, and the formal SRS is verified by a formal verification method. Through these activities, we believe we can achieve the functionality, performance, reliability, and safety that are the major V and V objectives of the nuclear safety-critical software in a DRPS. (authors)
Design Information from the PSA for Digital Safety-Critical Systems
International Nuclear Information System (INIS)
Kang, Hyun Gook; Jang, Seung Cheol
2005-01-01
Many safety-critical applications such as nuclear field application usually adopt a similar design strategy for digital safety-critical systems. Their differences from the normal design for the non-safety-critical applications could be summarized as: multiple-redundancy, highly reliable components, strengthened monitoring mechanism, verified software, and automated test procedure. These items are focusing on maintaining the capability to perform the given safety function when it is requested. For the past several decades, probabilistic safety assessment (PSA) techniques are used in the nuclear industry to assess the relative effects of contributing events on plant risk and system reliability. They provide a unifying means of assessing physical faults, recovery processes, contributing effects, human actions, and other events that have a high degree of uncertainty. The applications of PSA provide not only the analysis results of already installed system but also the useful information for the system under design. The information could be derived from the PSA experience of the various safety-critical systems. Thanks to the design flexibility, the digital system is one of the most suitable candidates for risk-informed design (RID). In this article, we will describe the feedbacks for system design and try to develop a procedure for RID. Even though the procedure is not sophisticated enough now, it could be the start point of the further investigation for developing more complete and practical methodology
SACS2: Dynamic and Formal Safety Analysis Method for Complex Safety Critical System
International Nuclear Information System (INIS)
Koh, Kwang Yong; Seong, Poong Hyun
2009-01-01
Fault tree analysis (FTA) is one of the most widely used safety analysis technique in the development of safety critical systems. However, over the years, several drawbacks of the conventional FTA have become apparent. One major drawback is that conventional FTA uses only static gates and hence can not capture dynamic behaviors of the complex system precisely. Although several attempts such as dynamic fault tree (DFT), PANDORA, formal fault tree (FFT) and so on, have been made to overcome this problem, they can not still do absolute or actual time modeling because they adapt relative time concept and can capture only sequential behaviors of the system. Second drawback of conventional FTA is its lack of rigorous semantics. Because it is informal in nature, safety analysis results heavily depend on an analyst's ability and are error-prone. Finally reasoning process which is to check whether basic events really cause top events is done manually and hence very labor-intensive and timeconsuming for the complex systems. In this paper, we propose a new safety analysis method for complex safety critical system in qualitative manner. We introduce several temporal gates based on timed computational tree logic (TCTL) which can represent quantitative notion of time. Then, we translate the information of the fault trees into UPPAAL query language and the reasoning process is automatically done by UPPAAL which is the model checker for time critical system
Applications of probabilistic risk analysis in nuclear criticality safety design
International Nuclear Information System (INIS)
Chang, J.K.
1992-01-01
Many documents have been prepared that try to define the scope of the criticality analysis and that suggest adding probabilistic risk analysis (PRA) to the deterministic safety analysis. The report of the US Department of Energy (DOE) AL 5481.1B suggested that an accident is credible if the occurrence probability is >1 x 10 -6 /yr. The draft DOE 5480 safety analysis report suggested that safety analyses should include the application of methods such as deterministic safety analysis, risk assessment, reliability engineering, common-cause failure analysis, human reliability analysis, and human factor safety analysis techniques. The US Nuclear Regulatory Commission (NRC) report NRC SG830.110 suggested that major safety analysis methods should include but not be limited to risk assessment, reliability engineering, and human factor safety analysis. All of these suggestions have recommended including PRA in the traditional criticality analysis
Role of criticality models in ANSI standards for nuclear criticality safety
International Nuclear Information System (INIS)
Thomas, J.T.
1976-01-01
Two methods used in nuclear criticality safety evaluations in the area of neutron interaction among subcritical components of fissile materials are the solid angle and surface density techniques. The accuracy and use of these models are briefly discussed
International Nuclear Information System (INIS)
Busch, R.D.
1990-01-01
Since 1973, the University of New Mexico (UNM) has given ten short courses in nuclear criticality safety (NCS). Generally, thee have been given every other year, although in 1989 it was decided to offer the course on an annual basis. This decision was primarily based on the large demand for NCS specialists and a large turnover rate in the industry. The purpose of the course is to provide a 1-week overview of NCS. The typical student has been involved in NCS for <1 yr, although it many cases they have been associated with the nuclear industry in other capacities for many years. The short course is conducted at several levels. Carefully prepared lectures provide the information framework for selected topics. The following topics are covered in the course: basic reactor theory, criticality accidents and consequences, hand calculations, administration of a criticality safety program, regulators and their processes, computer methods and applications, experimental methods and correlations, overview of some process operations, and transportation and storage issues in NCS
Safety of Nuclear Power Plants: Design. Specific Safety Requirements (French Edition)
International Nuclear Information System (INIS)
2017-01-01
This publication establishes requirements applicable to the design of nuclear power plants and elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. It will be useful for organizations involved in design, manufacture, construction, modification, maintenance, operation and decommissioning of nuclear power plants, as well as for regulatory bodies. A review of Safety Requirements publications was commenced in 2011 following the accident in the Fukushima Daiichi nuclear power plant in Japan. The review revealed no significant areas of weakness and resulted in just a small set of amendments to strengthen the requirements and facilitate their implementation, which are contained in the present publication.
Safety of Nuclear Power Plants: Design. Specific Safety Requirements (Russian Edition)
International Nuclear Information System (INIS)
2016-01-01
This publication establishes requirements applicable to the design of nuclear power plants and elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. It will be useful for organizations involved in design, manufacture, construction, modification, maintenance, operation and decommissioning of nuclear power plants, as well as for regulatory bodies. A review of Safety Requirements publications was commenced in 2011 following the accident in the Fukushima Daiichi nuclear power plant in Japan. The review revealed no significant areas of weakness and resulted in just a small set of amendments to strengthen the requirements and facilitate their implementation, which are contained in the present publication.
Safety of Nuclear Power Plants: Design. Specific Safety Requirements (Arabic Edition)
International Nuclear Information System (INIS)
2017-01-01
This publication establishes requirements applicable to the design of nuclear power plants and elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. It will be useful for organizations involved in design, manufacture, construction, modification, maintenance, operation and decommissioning of nuclear power plants, as well as for regulatory bodies. A review of Safety Requirements publications was commenced in 2011 following the accident in the Fukushima Daiichi nuclear power plant in Japan. The review revealed no significant areas of weakness and resulted in just a small set of amendments to strengthen the requirements and facilitate their implementation, which are contained in the present publication.
International Nuclear Information System (INIS)
Mezrahi, Arnaldo; Crispim, Verginia R.
2009-01-01
This work evaluates in a critical way the safety and radiological protection recommendations established by the International Atomic Energy Agency - IAEA and adopted national and internationally, for the transport of uranium and thorium ores and concentrates, known according the transport regulations, as being of the Low Specific Activity Material Type-I, LSA-I, basing on more realistic scenarios than the presently existent, aiming at the determination of maximum exposure levels of radiation as well as the maximal contents of those materials in packages and conveyance. A general overview taking into account the scenarios foreseen by the regulations of the IAEA pointed out for a need of a better justification of the requirements edited by the Agency or should be used to support a request of revision of those regulations, national and internationally adopted, in the pertinent aspects to the transport of uranium and thorium ores and concentrates. (author)
Criticality safety study of shutdown diffusion cascade coolers
International Nuclear Information System (INIS)
Paschal, L.S.; Basoglu, B.; Bentley, C.L.; Dunn, M.E.
1996-01-01
Gaseous diffusion plants use cascade coolers in the production of highly enriched uranium (HEU) to remove heat from the enriched stream of UF 6 . The cascade coolers operate like shell and tube heat exchangers with the UF 6 on the shell side and Freon on the tube side. Recirculating cooling water (RCW) in condensers is used to cool the Freon. A criticality safety analysis was previously performed for cascade coolers during normal operation. The purpose of this paper is to evaluate several different hypothetical accidents regarding RCW ingress into the cooler to determine whether criticality safety concerns exist
Technical bases for criticality safety standards
International Nuclear Information System (INIS)
Clayton, E.D.
1980-01-01
An American National Standard implies a consensus of those substantially concerned with its scope and provisions. The technical basis, or foundation, on which the consensus rests, must in turn, be firmly established and documented for public review. The technical bases are discussed and reviewed of several standards in different stages of completion and acceptance: ANSI/ANS-8.12, 1978, Nuclear Criticality Control and Safety of Homogeneous Plutonium - Uranium Mixtures Outside Reactors (Approved July 17, 1978); ANS-815, Nuclear Criticality Control of Special Actinide Elements (Draft No. 5 of newly proposed standard); ANS-8.14, Use of Solutions of Neutron Absorbers for Criticality Control (Draft No. 4 of newly proposed standard); ANS-8.5 (Revision of N16.4, 1971), Use of Borosilicate-Glass Raschig Rings as a Neutron Absorber in Solutions of Fissile Material (Draft No. 5 as a result of prescribed five-year review and update of old standard). In each of the preceding, the newly proposed (or revised) limits are based on the extension of experimental data via well established calculations, or by means of independent calculations with adequate margins for uncertainties. The four cases serve to illustrate the insight of the work group members in the establishment of the technical bases for the limits and the level of activity required on their part in the preparation of ANSI Standards. A time span of from four up to seven years has not been uncommon for the preparation, review, and acceptance of an ANSI Standard. 8 figures. 7 tables
Criticality safety study of dry spent fuel cask loaded with increased enrichment fuel
International Nuclear Information System (INIS)
Bznuni, S.; Baghdasaryan, N.; Amirjanyan, A.
2013-01-01
Existing Dry Spent Fuel Casks (DSC) for transporting and storing of Armenian NPP fuel was licensed for WWER-440 fuel assemblies with 3.6% enrichment. Having in mind that ANPP introduced new fuel assemblies with increased enrichment (3.82 %) re-assessment of criticality safety analysis for DSC is required. Criticality safety analysis of DSC was performed by KENO-VI program using 238-GROUP ENDF/B-VII.0 LIBRARY (V7-238). Results of analysis showed that additional 8 borated racks for fuel assemblies should be included in the design of DSC. In addition feasibility study was performed to find out level of burnup-credit approach implementation to keep current design of DSC unchanged. Burnup-credit analysis was performed by STARBUCS program using axial burnup profiles from Armenian NPP neutronics analysis carried out by BIPR code. (authors)
Energy Technology Data Exchange (ETDEWEB)
Kim, Taeman, E-mail: tmkim@korad.or.kr [Korea Radioactive Waste Agency (KORAD), 1045 Daedeokdaero, Yuseong-Gu, Daejeon 305-353 (Korea, Republic of); Dho, Hoseog; Baeg, Chang-Yeal [Korea Radioactive Waste Agency (KORAD), 1045 Daedeokdaero, Yuseong-Gu, Daejeon 305-353 (Korea, Republic of); Lee, Gang-uk [Korea Nuclear Engineering and Service Co. (KONES), Hyundai Plaza, 341-4 Jangdae-dong, Yuseong-gu, Daejeon (Korea, Republic of)
2014-10-15
Highlights: • DPC is under development led by Korea Radioactive Waste Agency in South Korea. • The results of criticality analysis with respect to design requirements. • The k{sub eff} under normal and off-normal conditions were 0.36 and 0.46, respectively. • In addition, the k{sub eff} under a postulated accident condition was evaluated to be 0.94. - Abstract: A dual-purpose metal cask is under development led by Korea Radioactive Waste Agency (KORAD) in Korea, for the dry interim storage and long-distance transportation. This cask comprises a main body made of carbon steel and a stainless steel Dry Shielded Canister (DSC), with stainless steel baskets inside to contain spent fuel assemblies. In this study, nuclear criticality safety analysis was conducted as a part of safety assessment of the metal cask. Analysis to show criticality safety in accordance with regulatory requirements of PWR spent fuel storage was carried out. 10CFR72.124 “Criteria for nuclear criticality safety” and the Regulatory Guide of the American Nuclear Society, ANSI/ANS-57.9 “Design Criteria for an Independent Spent Fuel” and US NRC's “Standard Review Plan for Spent Fuel Dry Storage Systems at a General License Facility” were employed as regulatory standard and criteria. This paper shows results of criticality analysis with respect to each designated criterion with modeling of a virtual nuclear fuel assembly and a cask body that induces the maximum reactivity among various design basis fuels of the metal cask. In addition, the sensitivity analysis of nuclear criticality taking into account the various modeling deviation such as manufacturing tolerance and modeling assumptions of conventional models was carried out to ensure the reliability of the analysis result. The criticality evaluation result of the metal cask and the maximum k{sub eff} under normal and off-normal conditions were 0.36884 and 0.46255, respectively. The maximum k{sub eff} under a postulated
International Nuclear Information System (INIS)
Doucet, M.; Zheng, S.; Mouton, J.; Porte, R.
2003-01-01
In France the 1999' Tokai Mura criticality accident in Japan had a big impact on the nuclear fuel manufacturing facility community. Moreover this accident led to a large public discussion about all the nuclear facilities. The French Safety Authorities made strong requirements to the industrials to revisit completely their safety analysis files mainly those concerning nuclear fuels treatments. The FRAMATOME-ANP production of its French low enriched (5 w/o) UO2 fuel fabrication plant (FBFC/Romans) exceeds 1000 metric tons a year. Special attention was given to the emergency evacuation plan that should be followed in case of a criticality accident. If a criticality accident happens, site internal and external radioprotection requirements need to have an emergency evacuation plan showing the different routes where the absorbed doses will be as low as possible for people. The French Safety Authorities require also an update of the old based neutron source term accounting for state of the art methodology. UO2 blenders units contain a large amount of dry powder strictly controlled by moderation; a hypothetical water leakage inside one of these apparatus is simulated by increasing the water content of the powder. The resulted reactivity insertion is performed by several static calculations. The French IRSN/CEA CRISTAL codes are used to perform these static calculations. The kinetic criticality code POWDER simulates the power excursion versus time and determines the consequent total energy source term. MNCP4B performs the source term propagation (including neutrons and gamma) used to determine the isodose curves needed to define the emergency evacuation plant. This paper deals with the approach FRAMATOME-ANP has taken to assess Safety Authorities demands using the more up to date calculation tools and methodology. (author)
International Nuclear Information System (INIS)
Tollefson, D.A.; Elliott, E.P.; Dyer, H.R.; Thompson, S.A.
1993-01-01
Validation of computer codes and nuclear data (cross-section) libraries using benchmark quality critical (or certain subcritical) experiments is an essential part of a nuclear criticality safety evaluation. The validation results establish the credibility of the calculational tools for use in evaluating a particular application. Validation of the calculational tools is addressed in several American National Standards Institute/American Nuclear Society (ANSI/ANS) standards, with ANSI/ANS-8.1 being the most relevant. Documentation of the validation is a required part of all safety analyses involving significant quantities of fissile materials. In the case of transportation of fissile materials, the safety analysis report for packaging (SARP) must contain a thorough discussion of benchmark experiments, detailing how the experiments relate to the significant packaging and contents materials (fissile, moderating, neutron absorbing) within the package. The experiments recommended in this paper are needed to address certain areas related to transportation of unirradiated fissile materials in drum-type containers (packagings) for which current data are inadequate or are lacking
Lecture Notes on Criticality Safety Validation Using MCNP & Whisper
Energy Technology Data Exchange (ETDEWEB)
Brown, Forrest B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rising, Michael Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Alwin, Jennifer Louise [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-03-11
Training classes for nuclear criticality safety, MCNP documentation. The need for, and problems surrounding, validation of computer codes and data area considered first. Then some background for MCNP & Whisper is given--best practices for Monte Carlo criticality calculations, neutron spectra, S(α,β) thermal neutron scattering data, nuclear data sensitivities, covariance data, and correlation coefficients. Whisper is computational software designed to assist the nuclear criticality safety analyst with validation studies with the Monte Carlo radiation transport package MCNP. Whisper's methodology (benchmark selection – Ck's, weights; extreme value theory – bias, bias uncertainty; MOS for nuclear data uncertainty – GLLS) and usage are discussed.
An evaluation of safety-critical Java on a Java processor
DEFF Research Database (Denmark)
Rios Rivas, Juan Ricardo; Schoeberl, Martin
2014-01-01
The safety-critical Java (SCJ) specification provides a restricted set of the Java language intended for applications that require certification. In order to test the specification, implementations are emerging and the need to evaluate those implementations in a systematic way is becoming important....... In this paper we evaluate our SCJ implementation which is based on the Java Optimized Processor JOP and we measure different performance and timeliness criteria relevant to hard real-time systems. Our implementation targets Level 0 and Level1 of the specification and to test it we use a series of micro...
Nuclear criticality safety analysis for the traveller PWR fuel shipping package
Energy Technology Data Exchange (ETDEWEB)
Vescovi, P.J.; Kent, N.A.; Casado, C.A. [Westinghouse Electric Co., LLC, Columbia, SC (United States)]|[ENUSA Industrias Avanzadas SA, Madrid (Spain)
2004-07-01
The Traveller PWR fresh fuel shipping package represents a radical departure from conventional PWR fuel package designs. Two immediately noticeable features of the Traveller are that it carries a single fuel assembly instead of two as do other package designs, and that it has built-in moderator, which forms part of the flux-trap system. The criticality safety case shows that the Traveller satisfies both U.S. and IAEA licensing requirements, and demonstrates that the package remains acceptably subcritical under normal conditions and hypothetical accident conditions of transport. This paper looks at the modeling techniques that were used to analyze the several accident scenarios that were considered, including: Lattice pitch expansion; Lattice pitch expansion along the fuel assembly length; Preferential flooding (selective flooding of different cavities); Differential flooding (varying water levels inside different cavities); Partial flooding (varying water density); Axial rod displacement; o Sensitivity studies of variable foam densities and boron content in packaging; Analysis for carrying loose rods in a rodbox; The criticality safety case for the Traveller proved to be a successful cooperative effort between ENUSA and Westinghouse.
Nuclear criticality safety analysis for the traveller PWR fuel shipping package
International Nuclear Information System (INIS)
Vescovi, P.J.; Kent, N.A.; Casado, C.A.
2004-01-01
The Traveller PWR fresh fuel shipping package represents a radical departure from conventional PWR fuel package designs. Two immediately noticeable features of the Traveller are that it carries a single fuel assembly instead of two as do other package designs, and that it has built-in moderator, which forms part of the flux-trap system. The criticality safety case shows that the Traveller satisfies both U.S. and IAEA licensing requirements, and demonstrates that the package remains acceptably subcritical under normal conditions and hypothetical accident conditions of transport. This paper looks at the modeling techniques that were used to analyze the several accident scenarios that were considered, including: Lattice pitch expansion; Lattice pitch expansion along the fuel assembly length; Preferential flooding (selective flooding of different cavities); Differential flooding (varying water levels inside different cavities); Partial flooding (varying water density); Axial rod displacement; o Sensitivity studies of variable foam densities and boron content in packaging; Analysis for carrying loose rods in a rodbox; The criticality safety case for the Traveller proved to be a successful cooperative effort between ENUSA and Westinghouse
Safety prediction for basic components of safety-critical software based on static testing
International Nuclear Information System (INIS)
Son, H.S.; Seong, P.H.
2000-01-01
The purpose of this work is to develop a safety prediction method, with which we can predict the risk of software components based on static testing results at the early development stage. The predictive model combines the major factor with the quality factor for the components, which are calculated based on the measures proposed in this work. The application to a safety-critical software system demonstrates the feasibility of the safety prediction method. (authors)
International Nuclear Information System (INIS)
Rathbun, R.
1994-01-01
Review of NMP-NCS-94-0087, ''Nuclear Criticality Safety Evaluation 94-02: Uranium Solidification Facility Pencil Tank Module Spacing (U), April 18, 1994,'' was requested of the SRTC Applied Physics Group. The NCSE is a criticality assessment to show that the USF process module spacing, as given in Non-Conformance Report SHM-0045, remains safe for operation. The NCSE under review concludes that the module spacing as given in Non-Conformance Report SHM-0045 remains in a critically safe configuration for all normal and single credible abnormal conditions. After a thorough review of the NCSE, this reviewer agrees with that conclusion
Criticality Safety Evaluation of Hanford Site High Level Waste Storage Tanks
Energy Technology Data Exchange (ETDEWEB)
ROGERS, C.A.
2000-02-17
This criticality safety evaluation covers operations for waste in underground storage tanks at the high-level waste tank farms on the Hanford site. This evaluation provides the bases for criticality safety limits and controls to govern receipt, transfer, and long-term storage of tank waste. Justification is provided that a nuclear criticality accident cannot occur for tank farms operations, based on current fissile material and operating conditions.
Criticality Safety Evaluation of Hanford Site High-Level Waste Storage Tanks
International Nuclear Information System (INIS)
ROGERS, C.A.
2000-01-01
This criticality safety evaluation covers operations for waste in underground storage tanks at the high-level waste tank farms on the Hanford site. This evaluation provides the bases for criticality safety limits and controls to govern receipt, transfer, and long-term storage of tank waste. Justification is provided that a nuclear criticality accident cannot occur for tank farms operations, based on current fissile material and operating conditions
Computational Methods for Sensitivity and Uncertainty Analysis in Criticality Safety
International Nuclear Information System (INIS)
Broadhead, B.L.; Childs, R.L.; Rearden, B.T.
1999-01-01
Interest in the sensitivity methods that were developed and widely used in the 1970s (the FORSS methodology at ORNL among others) has increased recently as a result of potential use in the area of criticality safety data validation procedures to define computational bias, uncertainties and area(s) of applicability. Functional forms of the resulting sensitivity coefficients can be used as formal parameters in the determination of applicability of benchmark experiments to their corresponding industrial application areas. In order for these techniques to be generally useful to the criticality safety practitioner, the procedures governing their use had to be updated and simplified. This paper will describe the resulting sensitivity analysis tools that have been generated for potential use by the criticality safety community
Towards the Verification of Safety-critical Autonomous Systems in Dynamic Environments
Directory of Open Access Journals (Sweden)
Adina Aniculaesei
2016-12-01
Full Text Available There is an increasing necessity to deploy autonomous systems in highly heterogeneous, dynamic environments, e.g. service robots in hospitals or autonomous cars on highways. Due to the uncertainty in these environments, the verification results obtained with respect to the system and environment models at design-time might not be transferable to the system behavior at run time. For autonomous systems operating in dynamic environments, safety of motion and collision avoidance are critical requirements. With regard to these requirements, Macek et al. [6] define the passive safety property, which requires that no collision can occur while the autonomous system is moving. To verify this property, we adopt a two phase process which combines static verification methods, used at design time, with dynamic ones, used at run time. In the design phase, we exploit UPPAAL to formalize the autonomous system and its environment as timed automata and the safety property as TCTL formula and to verify the correctness of these models with respect to this property. For the runtime phase, we build a monitor to check whether the assumptions made at design time are also correct at run time. If the current system observations of the environment do not correspond to the initial system assumptions, the monitor sends feedback to the system and the system enters a passive safe state.
Safety critical software design approach developed for Canadian nuclear power plants
International Nuclear Information System (INIS)
Ichiyen, M.M.; Joannou, P.K.
1995-01-01
Recently two methodologies were developed that comply with a high safety critical standard: the Rational Design Process, which can be characterized as a methodology based on state machines where the required behaviour of the software is defined using mathematical functions written in a notation which has a well defined syntax and semantics, and the Integrated Approach, which uses a graphical functional notation to specify the functional software requirements. The first implementations based on the two methodologies are discussed. Results from all phases of testing show a remarkably low number of errors, demonstrating that the new methodologies have indeed led to a higher demonstrable level of software reliability. (orig./HP) [de
Energy Requirements in Critically Ill Patients
2018-01-01
During the management of critical illness, optimal nutritional support is an important key for achieving positive clinical outcomes. Compared to healthy people, critically ill patients have higher energy expenditure, thereby their energy requirements and risk of malnutrition being increased. Assessing individual nutritional requirement is essential for a successful nutritional support, including the adequate energy supply. Methods to assess energy requirements include indirect calorimetry (IC) which is considered as a reference method, and the predictive equations which are commonly used due to the difficulty of using IC in certain conditions. In this study, a literature review was conducted on the energy metabolic changes in critically ill patients, and the implications for the estimation of energy requirements in this population. In addition, the issue of optimal caloric goal during nutrition support is discussed, as well as the accuracy of selected resting energy expenditure predictive equations, commonly used in critically ill patients.
Energy Requirements in Critically Ill Patients.
Ndahimana, Didace; Kim, Eun-Kyung
2018-04-01
During the management of critical illness, optimal nutritional support is an important key for achieving positive clinical outcomes. Compared to healthy people, critically ill patients have higher energy expenditure, thereby their energy requirements and risk of malnutrition being increased. Assessing individual nutritional requirement is essential for a successful nutritional support, including the adequate energy supply. Methods to assess energy requirements include indirect calorimetry (IC) which is considered as a reference method, and the predictive equations which are commonly used due to the difficulty of using IC in certain conditions. In this study, a literature review was conducted on the energy metabolic changes in critically ill patients, and the implications for the estimation of energy requirements in this population. In addition, the issue of optimal caloric goal during nutrition support is discussed, as well as the accuracy of selected resting energy expenditure predictive equations, commonly used in critically ill patients.
Criticality safety enhancements for SCALE 6.2 and beyond
International Nuclear Information System (INIS)
Rearden, Bradley T.; Bekar, Kursat B.; Celik, Cihangir; Clarno, Kevin T.; Dunn, Michael E.; Hart, Shane W.; Ibrahim, Ahmad M.; Johnson, Seth R.; Langley, Brandon R.; Lefebvre, Jordan P.; Lefebvre, Robert A.; Marshall, William J.; Mertyurek, Ugur; Mueller, Don; Peplow, Douglas E.; Perfetti, Christopher M.; Petrie Jr, Lester M.; Thompson, Adam B.; Wiarda, Dorothea; Wieselquist, William A.; Williams, Mark L.
2015-01-01
SCALE is a widely used suite of tools for nuclear systems modeling and simulation that provides comprehensive, verified and validated, user-friendly capabilities for criticality safety, reactor physics, radiation shielding, and sensitivity and uncertainty analysis. Since 1980, regulators, industry, and research institutions around the world have relied on SCALE for nuclear safety analysis and design. SCALE 6.2 provides several new capabilities and significant improvements in many existing features for criticality safety analysis. Enhancements are realized for nuclear data; multigroup resonance self-shielding; continuous-energy Monte Carlo analysis for sensitivity/uncertainty analysis, radiation shielding, and depletion; and graphical user interfaces. An overview of these capabilities is provided in this paper, and additional details are provided in several companion papers.
The development of safety requirements
International Nuclear Information System (INIS)
Jorel, M.
2009-01-01
This document describes the safety approach followed in France for the design of nuclear reactors. This safety approach is based on safety principles from which stem safety requirements that set limiting values for specific parameters. The improvements in computerized simulation, the use of more adequate new materials, a better knowledge of the concerned physical processes, the changes in the reactor operations (higher discharge burnups for instance) have to be taken into account for the definition of safety criteria and the setting of limiting values. The developments of the safety criteria linked to the risks of cladding failure and loss of primary coolant are presented. (A.C.)
International Nuclear Information System (INIS)
2016-01-01
This publication describes the requirements to be met to ensure the safe operation of nuclear power plants. It takes into account developments in areas such as long term operation of nuclear power plants, plant ageing, periodic safety review, probabilistic safety analysis and risk informed decision making processes. In addition, the requirements are governed by, and must apply, the safety objective and safety principles that are established in the IAEA Safety Standards Series No. SF-1, Fundamental Safety Principles. A review of Safety Requirements publications was commenced in 2011 following the accident in the Fukushima Daiichi nuclear power plant in Japan. The review revealed no significant areas of weakness and resulted in just a small set of amendments to strengthen the requirements and facilitate their implementation, which are contained in the present publication.
Safety Design Approach for the Development of Safety Requirements for Design of Commercial HTGR
International Nuclear Information System (INIS)
Ohashi, Hirofumi; Sato, Hiroyuki; Nakagawa, Shigeaki; Tachibana, Yukio; Nishihara, Tetsuo; Yan, Xing; Sakaba, Nariaki; Kunitomi, Kazuhiko
2014-01-01
The research committee on “Safety requirements for HTGR design” was established in 2013 under the Atomic Energy Society of Japan to develop the draft safety requirements for the design of commercial High Temperature Gas-cooled Reactors (HTGRs), which incorporate the HTGR safety features demonstrated using the High Temperature Engineering Test Reactor (HTTR), lessons learned from the accident of Fukushima Daiichi Nuclear Power Station and requirements for the integration of the hydrogen production plants. The safety design approach for the commercial HTGRs which is a basement of the safety requirements is determined prior to the development of the safety requirements. The safety design approaches for the commercial HTGRs are to confine the radioactive materials within the coated fuel particles not only during normal operation but also during accident conditions, and the integrity of the coated fuel particles and other requiring physical barriers are protected by the inherent and passive safety features. This paper describes the main topics of the research committee, the safety design approaches and the safety functions of the commercial HTGRs determined in the research committee. (author)
Safety prediction for basic components of safety critical software based on static testing
International Nuclear Information System (INIS)
Son, H.S.; Seong, P.H.
2001-01-01
The purpose of this work is to develop a safety prediction method, with which we can predict the risk of software components based on static testing results at the early development stage. The predictive model combines the major factor with the quality factor for the components, both of which are calculated based on the measures proposed in this work. The application to a safety-critical software system demonstrates the feasibility of the safety prediction method. (authors)
Safety Critical Java for Robotics Programming
DEFF Research Database (Denmark)
Thomsen, Bent; Luckow, Kasper Søe; Bøgholm, Thomas
2015-01-01
This paper introduces Safety Critical Java (SCJ) and argues its readiness for robotics programming. We give an overview of the work done at Aalborg University and elsewhere on SCJl, some of its implementations in the form of the JOP, FijiVM and HVM and some of the tools, especially WCA, Teta...
Nuclear Criticality Safety Organization training implementation. Revision 4
International Nuclear Information System (INIS)
Carroll, K.J.; Taylor, R.G.; Worley, C.A.
1997-01-01
The Nuclear Criticality Safety Organization (NCSO) is committed to developing and maintaining a staff of qualified personnel to meet the current and anticipated needs in Nuclear Criticality Safety (NCS) at the Oak Ridge Y-12 Plant. This document provides a listing of the roles and responsibilities of NCSO personnel with respect to training and details of the Training Management System (TMS) programs, Mentoring Checklists and Checksheets, as well as other documentation utilized to implement the program. This Training Implementation document is applicable to all technical and managerial NCSO personnel, including temporary personnel, sub-contractors and/or LMES employees on loan to the NCSO, who are in a qualification program
Nuclear Criticality Safety Organization training implementation. Revision 4
Energy Technology Data Exchange (ETDEWEB)
Carroll, K.J.; Taylor, R.G.; Worley, C.A.
1997-05-19
The Nuclear Criticality Safety Organization (NCSO) is committed to developing and maintaining a staff of qualified personnel to meet the current and anticipated needs in Nuclear Criticality Safety (NCS) at the Oak Ridge Y-12 Plant. This document provides a listing of the roles and responsibilities of NCSO personnel with respect to training and details of the Training Management System (TMS) programs, Mentoring Checklists and Checksheets, as well as other documentation utilized to implement the program. This Training Implementation document is applicable to all technical and managerial NCSO personnel, including temporary personnel, sub-contractors and/or LMES employees on loan to the NCSO, who are in a qualification program.
Belcastro, Christine M.
2010-01-01
Loss of control remains one of the largest contributors to aircraft fatal accidents worldwide. Aircraft loss-of-control accidents are highly complex in that they can result from numerous causal and contributing factors acting alone or (more often) in combination. Hence, there is no single intervention strategy to prevent these accidents and reducing them will require a holistic integrated intervention capability. Future onboard integrated system technologies developed for preventing loss of vehicle control accidents must be able to assure safe operation under the associated off-nominal conditions. The transition of these technologies into the commercial fleet will require their extensive validation and verification (V and V) and ultimate certification. The V and V of complex integrated systems poses major nontrivial technical challenges particularly for safety-critical operation under highly off-nominal conditions associated with aircraft loss-of-control events. This paper summarizes the V and V problem and presents a proposed process that could be applied to complex integrated safety-critical systems developed for preventing aircraft loss-of-control accidents. A summary of recent research accomplishments in this effort is also provided.
Development of Safety-Critical Software for Nuclear Power Plant using a CASE Tool
Energy Technology Data Exchange (ETDEWEB)
Kim, Chang Ho; Oh, Do Young; Kim, Koh Eun; Choi, Woong Seock; Sohn, Se Do; Kim, Jae Hack; Kim, Hang Bae [KEPCO E and C, Daejeon (Korea, Republic of)
2011-08-15
The Integrated SOftware Development Environment (ISODE) is developed to provide the major S/W life cycle processes that are composed of development process, V/V process, requirements traceability process, and automated document generation process and target importing process to Programmable Logic Controller (PLC) platform. This provides critical safety software developers with a certified, domain optimized, model-based development environment, and the associated services to reduce time and efforts to develop software such as debugging, simulation, code generation and document generation. This also provides critical safety software verifiers with integrated V/V features of each phase of the software life cycle using appropriate tools such as model test coverage, formal verification, and automated report generation. In addition to development and verification, the ISODE gives a complete traceability solution from the SW design phase to the testing phase. Using this information, the coverage and impact analysis can be done easily whenever software modification is necessary. The final source codes of ISODE are imported into the newly developed PLC environment, as a module based after automatically converted into the format required by PLC. Additional tests for module and unit level are performed on the target platform.
Development of Safety-Critical Software for Nuclear Power Plant using a CASE Tool
International Nuclear Information System (INIS)
Kim, Chang Ho; Oh, Do Young; Kim, Koh Eun; Choi, Woong Seock; Sohn, Se Do; Kim, Jae Hack; Kim, Hang Bae
2011-01-01
The Integrated SOftware Development Environment (ISODE) is developed to provide the major S/W life cycle processes that are composed of development process, V/V process, requirements traceability process, and automated document generation process and target importing process to Programmable Logic Controller (PLC) platform. This provides critical safety software developers with a certified, domain optimized, model-based development environment, and the associated services to reduce time and efforts to develop software such as debugging, simulation, code generation and document generation. This also provides critical safety software verifiers with integrated V/V features of each phase of the software life cycle using appropriate tools such as model test coverage, formal verification, and automated report generation. In addition to development and verification, the ISODE gives a complete traceability solution from the SW design phase to the testing phase. Using this information, the coverage and impact analysis can be done easily whenever software modification is necessary. The final source codes of ISODE are imported into the newly developed PLC environment, as a module based after automatically converted into the format required by PLC. Additional tests for module and unit level are performed on the target platform
Robust optical sensors for safety critical automotive applications
De Locht, Cliff; De Knibber, Sven; Maddalena, Sam
2008-02-01
Optical sensors for the automotive industry need to be robust, high performing and low cost. This paper focuses on the impact of automotive requirements on optical sensor design and packaging. Main strategies to lower optical sensor entry barriers in the automotive market include: Perform sensor calibration and tuning by the sensor manufacturer, sensor test modes on chip to guarantee functional integrity at operation, and package technology is key. As a conclusion, optical sensor applications are growing in automotive. Optical sensor robustness matured to the level of safety critical applications like Electrical Power Assisted Steering (EPAS) and Drive-by-Wire by optical linear arrays based systems and Automated Cruise Control (ACC), Lane Change Assist and Driver Classification/Smart Airbag Deployment by camera imagers based systems.
International Nuclear Information System (INIS)
Kim, Man Cheol; Jang, Seung Cheol; Ha, Jae Joo
2006-01-01
As digital systems are gradually introduced to nuclear power plants (NPPs), the need of quantitatively analyzing the reliability of the digital systems is also increasing. Kang and Sung identified (1) software reliability, (2) common-cause failures (CCFs), and (3) fault coverage as the three most critical factors in the reliability analysis of digital systems. For the estimation of the safety-critical software (the software that is used in safety-critical digital systems), the use of Bayesian Belief Networks (BBNs) seems to be most widely used. The use of BBNs in reliability estimation of safety-critical software is basically a process of indirectly assigning a reliability based on various observed information and experts' opinions. When software testing results or software failure histories are available, we can use a process of directly estimating the reliability of the software using various software reliability growth models such as Jelinski- Moranda model and Goel-Okumoto's nonhomogeneous Poisson process (NHPP) model. Even though it is generally known that software reliability growth models cannot be applied to safety-critical software due to small number of expected failure data from the testing of safety-critical software, we try to find possibilities and corresponding limitations of applying software reliability growth models to safety critical software
International Nuclear Information System (INIS)
2017-01-01
This publication is a revision of IAEA Safety Standards Series No. NS-R-2, Safety of Nuclear Power Plants: Operation, and has been extended to cover the commissioning stage. It describes the requirements to be met to ensure the safe commissioning, operation, and transition from operation to decommissioning of nuclear power plants. Over recent years there have been developments in areas such as long term operation of nuclear power plants, plant ageing, periodic safety review, probabilistic safety analysis review and risk informed decision making processes. It became necessary to revise the IAEA’s Safety Requirements in these areas and to correct and/or improve the publication on the basis of feedback from its application by both the IAEA and its Member States. In addition, the requirements are governed by, and must apply, the safety objective and safety principles that are established in the IAEA Safety Standards Series No. SF-1, Fundamental Safety Principles. A review of Safety Requirements publications, initiated in 2011 following the accident in the Fukushima Daiichi nuclear power plant in Japan, revealed no significant areas of weakness but resulted in a small set of amendments to strengthen the requirements and facilitate their implementation. These are contained in the present publication.
Radiation safety requirements for radionuclide laboratories
International Nuclear Information System (INIS)
1993-01-01
In accordance with the section 26 of the Finnish Radiation Act (592/91) the safety requirements to be taken into account in planning laboratories and other premises, which affect safety in the use of radioactive materials, are confirmed by the Finnish Centre for Radiation and Nuclear Safety. The guide specifies the requirements for laboratories and storage rooms in which radioactive materials are used or stored as unsealed sources. There are also some general instructions concerning work procedures in a radionuclide laboratory
Data-Centric Knowledge Discovery Strategy for a Safety-Critical Sensor Application
Directory of Open Access Journals (Sweden)
Nilamadhab Mishra
2014-01-01
Full Text Available In an indoor safety-critical application, sensors and actuators are clustered together to accomplish critical actions within a limited time constraint. The cluster may be controlled by a dedicated programmed autonomous microcontroller device powered with electricity to perform in-network time critical functions, such as data collection, data processing, and knowledge production. In a data-centric sensor network, approximately 3–60% of the sensor data are faulty, and the data collected from the sensor environment are highly unstructured and ambiguous. Therefore, for safety-critical sensor applications, actuators must function intelligently within a hard time frame and have proper knowledge to perform their logical actions. This paper proposes a knowledge discovery strategy and an exploration algorithm for indoor safety-critical industrial applications. The application evidence and discussion validate that the proposed strategy and algorithm can be implemented for knowledge discovery within the operational framework.
The International Criticality Safety Benchmark Evaluation Project on the Internet
International Nuclear Information System (INIS)
Briggs, J.B.; Brennan, S.A.; Scott, L.
2000-01-01
The International Criticality Safety Benchmark Evaluation Project (ICSBEP) was initiated in October 1992 by the US Department of Energy's (DOE's) defense programs and is documented in the Transactions of numerous American Nuclear Society and International Criticality Safety Conferences. The work of the ICSBEP is documented as an Organization for Economic Cooperation and Development (OECD) handbook, International Handbook of Evaluated Criticality Safety Benchmark Experiments. The ICSBEP Internet site was established in 1996 and its address is http://icsbep.inel.gov/icsbep. A copy of the ICSBEP home page is shown in Fig. 1. The ICSBEP Internet site contains the five primary links. Internal sublinks to other relevant sites are also provided within the ICSBEP Internet site. A brief description of each of the five primary ICSBEP Internet site links is given
Criticality safety evaluation of disposing of K Basin sludge in double-shell tank AW-105
International Nuclear Information System (INIS)
ROGERS, C.A.
1999-01-01
A criticality safety evaluation is made of the disposal of K Basin sludge in double-shell tank (DST) AW-105 located in the 200 east area of Hanford Site. The technical basis is provided for limits and controls to be used in the development of a criticality prevention specification (CPS). A model of K Basin sludge is developed to account for fuel burnup. The iron/uranium mass ration required to ensure an acceptable magrin of subcriticality is determined
A PLC generic requirements and specification for safety-related applications in nuclear power plants
International Nuclear Information System (INIS)
Han, Jea Bok; Lee, C. K.; Lee, D. Y.
2001-12-01
This report presents the requirements and specification to be applied to the generic qualification of programmable Logic Controller(PLC), which is being developed as part of the KNICS project, 'Development of the Digital Reactor Safety Systems' of which purpose is the application to safety-related instrumentation and control systems in nuclear power plants. This report defines the essential and critical characteristics that shall be included as part of a PLC design for safety-related application. The characteristics include performance, reliability, accuracy, the overall response time from an input to the PLC exceeding it trip condition to the resulting outputs, and the specification of processors and memories in digital controller. It also specifies the quality assurance process for software development, dealing with executive software, firmware, application software tools for developing the application software, and human machine interface(HMI). In addition, this report reviews the published standards and guidelines that are required for the PLC development and the quality assurance processes such as environment requirements, seismic withstand requirements, EMI/RFI withstand requirements, and isolation test
Memory Management for Safety-Critical Java
DEFF Research Database (Denmark)
Schoeberl, Martin
2011-01-01
Safety-Critical Java (SCJ) is based on the Real-Time Specification for Java. To simplify the certification of Java programs, SCJ supports only a restricted scoped memory model. Individual threads share only immortal memory and the newly introduced mission memory. All other scoped memories...... implementation is evaluated on an embedded Java processor....
Criticality safety for TMI-2 canister storage at INEL
International Nuclear Information System (INIS)
Jones, R.R.; Briggs, J.B.; Ayers, A.L. Jr.
1986-01-01
Canisters containing Three Mile Island Unit 2 (TMI-2) core debris will be researched, stored, and prepared for final disposition at the Idaho National Engineering Laboratory (INEL). The canisters will be placed into storage modules and assembled into a storage rack, which will be located in the Test Area North (TAN) storage pool. Criticality safety calculations were made (a) to ensure that the storage rack is safe for both normal and accident conditions and (b) to determine the effects of degradation of construction materials (Boraflex and polyethylene) on criticality safety
Safety-Critical Java for Embedded Systems
DEFF Research Database (Denmark)
Rios Rivas, Juan Ricardo
for Java aims at providing a reduced set of the Java programming language that can be used for systems that need to be certified at the highest levels of criticality. Safety-critical Java (SCJ) restricts how a developer can structure an application by providing a specific programming model...... and by restricting the set of methods and libraries that can be used. Furthermore, its memory model do not use a garbage-collected heap but scoped memories. In this thesis we examine the use of the SCJ specification through an implementation in a time-predictable, FPGA-based Java processor. The specification is now...
Critical incidents related to cardiac arrests reported to the Danish Patient Safety Database
DEFF Research Database (Denmark)
Andersen, Peter Oluf; Maaløe, Rikke; Andersen, Henning Boje
2010-01-01
Background Critical incident reports can identify areas for improvement in resuscitation practice. The Danish Patient Safety Database is a mandatory reporting system and receives critical incident reports submitted by hospital personnel. The aim of this study is to identify, analyse and categorize...... critical incidents related to cardiac arrests reported to the Danish Patient Safety Database. Methods The search terms “cardiac arrest” and “resuscitation” were used to identify reports in the Danish Patient Safety Database. Identified critical incidents were then classified into categories. Results One...
Assessment of criticality safety
International Nuclear Information System (INIS)
Lloyd, R.C.; Heaberlin, S.W.; Clayton, E.D.; Carter, R.D.
1979-01-01
A study was made of 100 violations of criticality safety specifications reported over a 10-y period in the operations of fuel reprocessing plants. The seriousness of each rule violation was evaluated by assigning it a severity index value. The underlying causes or reasons, for the violations were identified. A criticality event tree was constructed using the parameters, causes, and reasons found in the analysis of the infractions. The event tree provides a means for visualizing the paths to an accidental criticality. Some 65% of the violations were caused by misinterpretation on the part of the operator, being attributed to a lack of clarity in the specification and insufficient training; 33% were attributed to lack of care, whereas only 2% were caused by mechanical failure. A fault tree was constructed by assembling the events that could contribute to an accident. With suitable data on the probabilities of contributing events, the probability of the accident's occurrence can be forecast. Estimated probabilities for criticality were made, based on the limited data available, that in this case indicate a minimum time span of 244 y of plant operation per accident ranging up to approx. 3000 y subject to the various underlying assumptions made. Some general suggestions for improvement are formulated based on the cases studied. Although conclusions for other plants may differ in detail, the general method of analysis and the fault tree logic should prove applicable. 4 figures, 8 tables
High level issues in reliability quantification of safety-critical software
International Nuclear Information System (INIS)
Kim, Man Cheol
2012-01-01
For the purpose of developing a consensus method for the reliability assessment of safety-critical digital instrumentation and control systems in nuclear power plants, several high level issues in reliability assessment of the safety-critical software based on Bayesian belief network modeling and statistical testing are discussed. Related to the Bayesian belief network modeling, the relation between the assessment approach and the sources of evidence, the relation between qualitative evidence and quantitative evidence, how to consider qualitative evidence, and the cause-consequence relation are discussed. Related to the statistical testing, the need of the consideration of context-specific software failure probabilities and the inability to perform a huge number of tests in the real world are discussed. The discussions in this paper are expected to provide a common basis for future discussions on the reliability assessment of safety-critical software. (author)
Criticality safety considerations. Integral Monitored Retrievable Storage (MRS) Facility
International Nuclear Information System (INIS)
1986-09-01
This report summarizes the criticality analysis performed to address criticality safety concerns and to support facility design during the conceptual design phase of the Monitored Retrievable Storage (MRS) Facility. The report addresses the criticality safety concerns, the design features of the facility relative to criticality, and the results of the analysis of both normal operating and hypothetical off-normal conditions. Key references are provided (Appendix C) if additional information is desired by the reader. The MRS Facility design was developed and the related analysis was performed in accordance with the MRS Facility Functional Design Criteria and the Basis for Design. The detailed description and calculations are documented in the Integral MRS Facility Conceptual Design Report. In addition to the summary portion of this report, explanatary notes for various terms, calculation methodology, and design parameters are presented in Appendix A. Appendix B provides a brief glossary of technical terms
Parametric Criticality Safety Calculations for Arrays of TRU Waste Containers
Energy Technology Data Exchange (ETDEWEB)
Gough, Sean T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-10-26
The Nuclear Criticality Safety Division (NCSD) has performed criticality safety calculations for finite and infinite arrays of transuranic (TRU) waste containers. The results of these analyses may be applied in any technical area onsite (e.g., TA-54, TA-55, etc.), as long as the assumptions herein are met. These calculations are designed to update the existing reference calculations for waste arrays documented in Reference 1, in order to meet current guidance on calculational methodology.
Safety critical application of fuzzy control
International Nuclear Information System (INIS)
Schildt, G.H.
1995-01-01
After an introduction into safety terms a short description of fuzzy logic will be given. Especially, for safety critical applications of fuzzy controllers a possible controller structure will be described. The following items will be discussed: Configuration of fuzzy controllers, design aspects like fuzzfiication, inference strategies, defuzzification and types of membership functions. As an example a typical fuzzy rule set will be presented. Especially, real-time behaviour a fuzzy controllers is mentioned. An example of fuzzy controlling for temperature control purpose within a nuclear reactor together with membership functions and inference strategy of such a fuzzy controller will be presented. (author). 4 refs, 17 figs
Investigation on regulatory requirements for radiation safety management
International Nuclear Information System (INIS)
Han, Eun Ok; Choi, Yoon Seok; Cho, Dae Hyung
2013-01-01
NRC recognizes that efficient management of radiation safety plan is an important factor to achieve radiation safety service. In case of Korea, the contents to perform the actual radiation safety management are legally contained in radiation safety management reports based on the Nuclear Safety Act. It is to prioritize the importance of safety regulations in each sector in accordance with the current situation of radiation and radioactive isotopes-used industry and to provide a basis for deriving safety requirements and safety regulations system maintenance by the priority of radiation safety management regulations. It would be helpful to achieve regulations to conform to reality based on international standards if consistent safety requirements is developed for domestic users, national standards and international standards on the basis of the results of questions answered by radiation safety managers, who lead on-site radiation safety management, about the priority of important factors in radioactive sources use, sales, production, moving user companies, to check whether derived configuration requirements for radiation safety management are suitable for domestic status
Nuclear data needs within the U. S. Nuclear Criticality Safety program
International Nuclear Information System (INIS)
McKnight, R.D.; Dunn, M.E.; Little, R.C.; Felty, J.R.; McKamy, J.N.
2008-01-01
This paper will present the nuclear data needs currently identified within the US Nuclear Criticality Safety Program (NCSP). It will identify the priority data needs; it will describe the process of prioritizing those needs; and it will provide brief examples of recent data advances which have successfully addressed some of the priority criticality safety data needs.
Tool-based requirement traceability between requirement and design artifacts
Turban, Bernhard
2013-01-01
Processes for developing safety-critical systems impose special demands on ensuring requirements traceability. Achieving valuable traceability information, however, is especially difficult concerning the transition from requirements to design. Bernhard Turban analyzes systems and software engineering theories cross-cutting the issue (embedded systems development, systems engineering, software engineering, requirements engineering and management, design theory and processes for safety-critical systems). As a solution, the author proposes a new tool approach to support designers in their thinkin
Model checking of safety-critical software in the nuclear engineering domain
International Nuclear Information System (INIS)
Lahtinen, J.; Valkonen, J.; Björkman, K.; Frits, J.; Niemelä, I.; Heljanko, K.
2012-01-01
Instrumentation and control (I and C) systems play a vital role in the operation of safety-critical processes. Digital programmable logic controllers (PLC) enable sophisticated control tasks which sets high requirements for system validation and verification methods. Testing and simulation have an important role in the overall verification of a system but are not suitable for comprehensive evaluation because only a limited number of system behaviors can be analyzed due to time limitations. Testing is also performed too late in the development lifecycle and thus the correction of design errors is expensive. This paper discusses the role of formal methods in software development in the area of nuclear engineering. It puts forward model checking, a computer-aided formal method for verifying the correctness of a system design model, as a promising approach to system verification. The main contribution of the paper is the development of systematic methodology for modeling safety critical systems in the nuclear domain. Two case studies are reviewed, in which we have found errors that were previously not detected. We also discuss the actions that should be taken in order to increase confidence in the model checking process.
Dozza, Marco; González, Nieves Pañeda
2013-11-01
New trends in research on traffic accidents include Naturalistic Driving Studies (NDS). NDS are based on large scale data collection of driver, vehicle, and environment information in real world. NDS data sets have proven to be extremely valuable for the analysis of safety critical events such as crashes and near crashes. However, finding safety critical events in NDS data is often difficult and time consuming. Safety critical events are currently identified using kinematic triggers, for instance searching for deceleration below a certain threshold signifying harsh braking. Due to the low sensitivity and specificity of this filtering procedure, manual review of video data is currently necessary to decide whether the events identified by the triggers are actually safety critical. Such reviewing procedure is based on subjective decisions, is expensive and time consuming, and often tedious for the analysts. Furthermore, since NDS data is exponentially growing over time, this reviewing procedure may not be viable anymore in the very near future. This study tested the hypothesis that automatic processing of driver video information could increase the correct classification of safety critical events from kinematic triggers in naturalistic driving data. Review of about 400 video sequences recorded from the events, collected by 100 Volvo cars in the euroFOT project, suggested that drivers' individual reaction may be the key to recognize safety critical events. In fact, whether an event is safety critical or not often depends on the individual driver. A few algorithms, able to automatically classify driver reaction from video data, have been compared. The results presented in this paper show that the state of the art subjective review procedures to identify safety critical events from NDS can benefit from automated objective video processing. In addition, this paper discusses the major challenges in making such video analysis viable for future NDS and new potential
Merger of Nuclear Data with Criticality Safety Calculations
Energy Technology Data Exchange (ETDEWEB)
Derrien, H.; Larson, N.M.; Leal, L.C.
1999-09-20
In this paper we report on current activities related to the merger of differential/integral data (especially in the resolved-resonance region) with nuclear criticality safety computations. Techniques are outlined for closer coupling of many processes � measurement, data reduction, differential-data analysis, integral-data analysis, generating multigroup cross sections, data-testing, criticality computations � which in the past have been treated independently.
Merger of Nuclear Data with Criticality Safety Calculations
International Nuclear Information System (INIS)
Derrien, H.; Larson, N.M.; Leal, L.C.
1999-01-01
In this paper we report on current activities related to the merger of differential/integral data (especially in the resolved-resonance region) with nuclear criticality safety computations. Techniques are outlined for closer coupling of many processes measurement, data reduction, differential-data analysis, integral-data analysis, generating multigroup cross sections, data-testing, criticality computations which in the past have been treated independently
Nuclear criticality safety assessment of ORR, NBS, and HFBR fuel element shipping package
International Nuclear Information System (INIS)
Thomas, J.T.
1979-01-01
A fuel element shipping package employing a borated-phenolic foam as a thermal insulating material is designed to transport as many as seven fuel elements for use in the Oak Ridge Research Reactor, the Brookhaven Fast Beam Reactor, or the National Bureau of Standards Reactor. This report presents the criticality safety evaluation and demonstrates that the requirements for a Fissile Class I package are satisfied by the design
International Nuclear Information System (INIS)
Mitake, Susumu
2003-01-01
Validation of the continuous-energy Monte Carlo criticality-safety analysis system, comprising the MVP code and neutron cross sections based on JENDL-3.2, was examined using benchmarks evaluated in the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments'. Eight experiments (116 configurations) for the plutonium solution and plutonium-uranium mixture systems performed at Valduc, Battelle Pacific Northwest Laboratories, and other facilities were selected and used in the studies. The averaged multiplication factors calculated with MVP and MCNP-4B using the same neutron cross-section libraries based on JENDL-3.2 were in good agreement. Based on methods provided in the Japanese nuclear criticality-safety handbook, the estimated criticality lower-limit multiplication factors to be used as a subcriticality criterion for the criticality-safety evaluation of nuclear facilities were obtained. The analysis proved the applicability of the MVP code to the criticality-safety analysis of nuclear fuel facilities, particularly to the analysis of systems fueled with plutonium and in homogeneous and thermal-energy conditions
Accomplishment of 10-year research in NUCEF and future development. Criticality safety research
International Nuclear Information System (INIS)
Miyoshi, Yoshinori
2005-01-01
Since 1995, static and transient critical experiments on low enriched uranyl nitrate solution have been performed using two solution type criticality facilities, STACY and TRACY constructed in NUCEF. The obtained fundamental and systematic data on aqueous solution were used to validate the criticality safety calculation codes and to develop the transient analyses codes for criticality accident evaluation. This paper describes the outline of the criticality safety research conducted in NUCEF. (author)
SRTC criticality safety technical review of SRT-CMA-930039
International Nuclear Information System (INIS)
Rathbun, R.
1993-01-01
Review of SRT-CMA-930039, ''Nuclear Criticality Safety Evaluation (NCSE): DWPF Melter-Batch 1,'' December 1, 1993, has been performed by the Savannah River Technical Center (SRTC) Applied Physics Group. The NCSE is a criticality assessment of the Melt Cell in the DWPF. Additionally, this pertains only to Batch 1 operation, which differs from batches to follow. Plans for subsequent batch operations call for fissile material in the Salt Cell feed-stream, which necessitates a separate criticality evaluation in the future. The NCSE under review concludes that the process is safe from criticality events, even in the event that all lithium and boron neutron poisons are lost, provided uranium enrichments are less than 40%. Furthermore, if all the lithium and as much as 98% of the boron would be lost, uranium enrichments of 100% would be allowable. After a thorough review of the NCSE, this reviewer agrees with that conclusion. This technical review consisted of: an independent check of the methods and models employed, independent calculations application of ANSI/ANS 8.1, verification of WSRC Nuclear Criticality Safety Manual( 2 ) procedures
Safety requirements applicable to the SMART design
International Nuclear Information System (INIS)
Seul, Kwang Won; Kim, Wee Kyong; Kim, Hho Jung
1999-01-01
The 330 MW thermal power of integral reactor, named SMART (System integrated Modular Advanced ReacTor), is under development at KAERI for seawater desalination application and electricity generation. The final product of nuclear desalination plant (NDP) is electricity and fresh water. Thus, in addition to the protection of the public around the plant facility from the possible release of radioactive materials, the fresh water should be prevented from radioactivity contamination. In this study, to ensure the safety of SMART reactor in the early stage of design development, the safety requirements applicable to the SMART design were investigated, based on the current regulatory requirements for the existing NPPs and the advanced light water reactor (LWR) designs. The interface requirements related to the desalination facility were also investigated, based on the recent IAEA research activities pertaining to the NDP. As a result, it was found that the current regulatory requirements and guidance for the existing NPPs and advanced LWR designs are applicable to the SMART design and its safety evaluation. However, the safety requirements related to the SMART-specific design and the desalination plant are needed to develop in the future to assure the safety of the SMART reactor
Criticality safety analyses in SKODA JS a.s
International Nuclear Information System (INIS)
Mikolas, P.; Svarny, J.
1999-01-01
This paper describes criticality safety analyses of spent fuel systems for storage and transport of spent fuel performed in SKODA JS s.r.o.. Analyses were performed for different systems both at NPP site including originally designed spent fuel pool with a large pitch between assemblies without any special absorbing material, high density spent fuel pool with an additional absorption by boron steel, depository rack for fresh fuel assemblies with a very large pitch between fuel assemblies, a container for transport of fresh fuel into the reactor pool and a cask for transport and storage of spent fuel and container for final storage depository. required subcriticality has been proven taking into account all possible unfavourable conditions, uncertainties etc. In two cases, burnup credit methodology is expected to be used. (Authors)
HTR-PM Safety requirement and Licensing experience
International Nuclear Information System (INIS)
Li Fu; Zhang Zuoyi; Dong Yujie; Wu Zongxin; Sun Yuliang
2014-01-01
HTR-PM is a 200MWe modular pebble bed high temperature reactor demonstration plant which is being built in Shidao Bay, Weihai, Shandong, China. The main design parameters of HTR-PM were fixed in 2006, the basic design was completed in 2008. The review of Preliminary Safety Analysis Report (PSAR) of HTR-PM was started in April 2008, completed in September 2009. In general, HTR- PM design complies with the current safety requirement for nuclear power plant in China, no special standards are developed for modular HTR. Anyway, Chinese Nuclear Safety Authority, together with the designers, developed some dedicated design criteria for key systems and components and published the guideline for the review of safety analysis report of HTR-PM, based on the experiences from licensing of HTR-10 and new development of nuclear safety. The probabilistic safety goal for HTR-PM was also defined by the safety authority. The review of HTR-PM PSAR lasted for one and a half years, with 3 dialogues meetings and 8 topics meetings, with more than 2000 worksheets and answer sheets. The heavily discussed topics during the PSAR review process included: the requirement for the sub-atmospheric ventilation system, the utilization of PSA in design process, the scope of beyond design basis accidents, the requirement for the qualification of TRISO coating particle fuel, and etc. Because of the characteristics of first of a kind for the demonstration plant, the safety authority emphasized the requirement for the experiment and validation, the PSAR was licensed with certain licensing conditions. The whole licensing process was under control, and was re-evaluated again after Fukushima accident to be shown that the design of HTR-PM complies with current safety requirement. This is a good example for how to license a new reactor. (author)
Criticality safety analysis for mockup facility
International Nuclear Information System (INIS)
Shin, Young Joon; Shin, Hee Sung; Kim, Ik Soo; Oh, Seung Chul; Ro, Seung Gy; Bae, Kang Mok
2000-03-01
Benchmark calculations for SCALE4.4 CSAS6 module have been performed for 31 UO 2 fuel, 15MOX fuel and 10 metal material criticality experiments and then calculation biases of the SCALE 4.4 CSAS6 module have been revealed to be 0.00982, 0.00579 and 0.02347, respectively. When CSAS6 is applied to the criticality safety analysis for the mockup facility in which several kinds of nuclear material components are included, the calculation bias of CSAS6 is conservatively taken to be 0.02347. With the aid of this benchmarked code system, criticality safety analyses for the mockup facility at normal and hypothetical accidental conditions have been carried out. It appears that the maximum K eff is 0.28356 well below than the critical limit, K eff =0.95 at normal condition. In a hypothetical accidental condition, the maximum K eff is found to be 0.73527 much lower than the subcritical limit. For another hypothetical accidental condition the nuclear material leaks out of container and spread or lump in the floor, it was assumed that the nuclear material is shaped into a slab and water exists in the empty space of the nuclear material. K eff has been calculated as function of slab thickness and the volume ratio of water to nuclear material. The result shows that the K eff increases as the water volume ratio increases. It is also revealed that the K eff reaches to the maximum value when water if filled in the empty space of nuclear material. The maximum K eff value is 0.93960 lower than the subcritical limit
Criticality safety analysis of a calciner exit chute
International Nuclear Information System (INIS)
Haught, C.F.; Basoglu, B.; Brewer, R.W.; Hollenback, D.F.; Wilkinson, A.D.; Dodds, H.L.
1994-01-01
Calcination of uranyl nitrate into uranium oxide is part of normal operations of some enrichment plants. Typically, a calciner discharges uranium oxide powder (U 3 O 8 ) into an exit chute that directs the powder into a receiving can located in a glove box. One possible scenario for a criticality accident is the exit chute becoming blocked with powder near its discharge. The blockage restricts the flow of powder causing the exit chute to become filled with the powder. If blockage does occur, the height of the powder could reach a level that would not be safe from a criticality point of view. In this analysis, the subcritical height limit is examined for 98% enriched U 3 O 8 in the exit chute with full water reflection and optimal water moderation. The height limit for ensuring criticality safety during such an accumulation is 28.2 cm above the top of the discharge pipe at the bottom of the chute. Chute design variations are also evaluated with full water reflection and optimal water moderation. Subcritical configurations for the exit chute variation are developed, but the configurations are not safe when combined with the calciner. To ensure criticality safety, modifications must be made to the calciner tube or safety measures must be implemented if these designs are to be utilized with 98% enriched material. A geometrically safe configuration for the exit chute is developed for a blockage of 20% enriched powder with full water reflection and optimal water moderation, and this configuration is safe when combined with the existing calciner
Regulatory aspects of criticality control in Australia
International Nuclear Information System (INIS)
Zimin, Sergei
2003-01-01
With the creation of Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) the Australian approach to criticality safety was revisited. Consistency with international best practices is required by the Act that created ARPANSA and this was applied to practices in criticality safety adopted in other countries. This required extensive regulatory efforts both in auditing the major Australian Nuclear Operator, Australian Nuclear Science and Technology Organisation (ANSTO), and assessing the existing in Australia criticality safety practices and implementing the required changes using the new legislative power of ARPANSA. The adopted regulatory approach is formulated through both the issued by ARPANSA licenses for nuclear installations (including reactors, fuel stores and radioactive waste stores) and the string of new regulatory documents, including the Regulatory Assessment Principles and the Regulatory Assessment Guidelines for criticality safety. The main features of the adopted regulation include the requirements of independent peer-review, ongoing refresher training coupled with annual accreditation and the reliance on the safe design rather than on an administrative control. (author)
Criticality safety evaluation report for K Basin filter cartridges
International Nuclear Information System (INIS)
Schwinkendorf, K.N.
1995-01-01
A criticality safety evaluation of the K Basin filter cartridge assemblies has been completed to support operations without a criticality alarm system. The results show that for normal operation, the filter cartridge assembly is far below the safety limit of k eff = 0.95, which is applied to plutonium systems at the Hanford Site. During normal operating conditions, uranium, plutonium, and fission and corrosion products in solution are continually accumulating in the available void spaces inside the filter cartridge medium. Currently, filter cartridge assemblies are scheduled to be replaced at six month intervals in KE Basin, and at one year intervals in KW Basin. According to available plutonium concentration data for KE Basin and data for the U/Pu ratio, it will take many times the six-month replacement time for sufficient fissionable material accumulation to take place to exceed the safety limit of k eff = 0.95, especially given the conservative assumption that the presence of fission and corrosion products is ignored. Accumulation of sludge with a composition typical of that measured in the sand filter backwash pit will not lead to a k eff = 0.95 value. For off-normal scenarios, it would require at least two unlikely, independent, and concurrent events to take place before the k eff = 0.95 limit was exceeded. Contingencies considered include failure to replace the filter cartridge assemblies at the scheduled time resulting in additional buildup of fissionable material, the loss of geometry control from the filter cartridge assembly breaking apart and releasing the individual filter cartridges into an optimal configuration, and concentrations of plutonium at U/Pu ratios less than measured data for KE Basin, typically close to 400 according to extensive measurements in the sand filter backwash pit and plutonium production information
Geological disposal of radioactive waste. Safety requirements
International Nuclear Information System (INIS)
2006-01-01
This Safety Requirements publication is concerned with providing protection to people and the environment from the hazards associated with waste management activities related to disposal, i.e. hazards that could arise during the operating period and following closure. It sets out the protection objectives and criteria for geological disposal and establishes the requirements that must be met to ensure the safety of this disposal option, consistent with the established principles of safety for radioactive waste management. It is intended for use by those involved in radioactive waste management and in making decisions in relation to the development, operation and closure of geological disposal facilities, especially those concerned with the related regulatory aspects. This publication contains 1. Introduction; 2. Protection of human health and the environment; 3. The safety requirements for geological disposal; 4. Requirements for the development, operation and closure of geological disposal facilities; Appendix: Assurance of compliance with the safety objective and criteria; Annex I: Geological disposal and the principles of radioactive waste management; Annex II: Principles of radioactive waste management
A systematic approach for safety evidence collection in the safety-critical domain
Lin, H.; Wu, Ji; Yuan, C.; Luo, Y.; Brand, van den M.G.J.; Engelen, L.J.P.
2015-01-01
In order to show that the required safety objectives are met, it is necessary to collect safety evidence in the form of consistent and complete data. However, manual safety evidence collection is usually tedious and time-consuming, due to a large number of artifacts and implicit relations between
Diversity for security: case assessment for FPGA-based safety-critical systems
Directory of Open Access Journals (Sweden)
Kharchenko Vyacheslav
2016-01-01
Full Text Available Industrial safety critical instrumentation and control systems (I&Cs are facing more with information (in general and cyber, in particular security threats and attacks. The application of programmable logic, first of all, field programmable gate arrays (FPGA in critical systems causes specific safety deficits. Security assessment techniques for such systems are based on heuristic knowledges and the expert judgment. Main challenge is how to take into account features of FPGA technology for safety critical I&Cs including systems in which are applied diversity approach to minimize risks of common cause failure. Such systems are called multi-version (MV systems. The goal of the paper is in description of the technique and tool for case-based security assessment of MV FPGA-based I&Cs.
International Nuclear Information System (INIS)
Gore, B.F.; Davenport, L.C.
1981-04-01
Factors affecting the safety of criticality experiments using heterogeneous assemblies are described and assessed. It is concluded that there is no substantial change in safety from experiments already being routinely performed at the Critical Mass Laboratory (CML), and that laboratory and personnel safety are adequately provided by the combination of engineered and administrative safety limits enforced at the CML. This conclusion is based on the analysis of operational controls, potential hazards, and the consequences of accidents. Contingencies considered that could affect nuclear criticality include manual changes in fuel loadings, water flooding, fire, explosion, loss of services, earthquake, windstorm, and flood. Other potential hazards considered include radiation exposure to personnel, and potential releases within the Assembly Room and outside to the environment. It is concluded that the Maximum Credible Nuclear Burst of 3 x 10 18 fissions (which served as the design basis for the CML) is valid for heterogeneous assemblies as well as homogeneous assemblies. This is based upon examination of the results of reactor destructive tests and the results of the SL-1 reactor destructive accident. The production of blast effects which might jeopardize the CML critical assembly room (of thick reinforced concrete) is not considered credible due to the extreme circumstances required to produce blast effects in reactor destructive tests. Consequently, it is concluded that, for experiments with heterogeneous assemblies, the consequences of the Maximum Credible Burst are unchanged from those previously estimated for experiments with homogeneous systems
Benchmarking criticality safety calculations with subcritical experiments
International Nuclear Information System (INIS)
Mihalczo, J.T.
1984-06-01
Calculation of the neutron multiplication factor at delayed criticality may be necessary for benchmarking calculations but it may not be sufficient. The use of subcritical experiments to benchmark criticality safety calculations could result in substantial savings in fuel material costs for experiments. In some cases subcritical configurations could be used to benchmark calculations where sufficient fuel to achieve delayed criticality is not available. By performing a variety of measurements with subcritical configurations, much detailed information can be obtained which can be compared directly with calculations. This paper discusses several measurements that can be performed with subcritical assemblies and presents examples that include comparisons between calculation and experiment where possible. Where not, examples from critical experiments have been used but the measurement methods could also be used for subcritical experiments
The Qualification Experiences for Safety-critical Software of POSAFE-Q
Energy Technology Data Exchange (ETDEWEB)
Kim, Jang Yeol; Son, Kwang Seop; Cheon, Se Woo; Lee, Jang Soo; Kwon, Kee Choon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2009-05-15
Programmable Logic Controllers (PLC) have been applied to the Reactor Protection System (RPS) and the Engineered Safety Feature (ESF)-Component Control System (CCS) as the major safety system components of nuclear power plants. This paper describes experiences on the qualification of the safety-critical software including the pCOS kernel and system tasks related to a safety-grade PLC, i.e. the works done for the Software Verification and Validation, Software Safety Analysis, Software Quality Assurance, and Software Configuration Management etc.
Safety impacts of bicycle infrastructure: A critical review.
DiGioia, Jonathan; Watkins, Kari Edison; Xu, Yanzhi; Rodgers, Michael; Guensler, Randall
2017-06-01
This paper takes a critical look at the present state of bicycle infrastructure treatment safety research, highlighting data needs. Safety literature relating to 22 bicycle treatments is examined, including findings, study methodologies, and data sources used in the studies. Some preliminary conclusions related to research efficacy are drawn from the available data and findings in the research. While the current body of bicycle safety literature points toward some defensible conclusions regarding the safety and effectiveness of certain bicycle treatments, such as bike lanes and removal of on-street parking, the vast majority treatments are still in need of rigorous research. Fundamental questions arise regarding appropriate exposure measures, crash measures, and crash data sources. This research will aid transportation departments with regard to decisions about bicycle infrastructure and guide future research efforts toward understanding safety impacts of bicycle infrastructure. Copyright © 2017 Elsevier Ltd and National Safety Council. All rights reserved.
Intermediate probabilistic safety assessment approach for safety critical digital systems
International Nuclear Information System (INIS)
Taeyong, Sung; Hyun Gook, Kang
2001-01-01
Even though the conventional probabilistic safety assessment methods are immature for applying to microprocessor-based digital systems, practical needs force to apply it. In the Korea, UCN 5 and 6 units are being constructed and Korean Next Generation Reactor is being designed using the digital instrumentation and control equipment for the safety related functions. Korean regulatory body requires probabilistic safety assessment. This paper analyzes the difficulties on the assessment of digital systems and suggests an intermediate framework for evaluating their safety using fault tree models. The framework deals with several important characteristics of digital systems including software modules and fault-tolerant features. We expect that the analysis result will provide valuable design feedback. (authors)
Formal model-based development for safety-critical embedded software
International Nuclear Information System (INIS)
Kim, Jin Hyun; Choi, Jin Young
2005-01-01
Safety-critical embedded software for nuclear I and C system is developed under the safety and reliability regulation. Programmable logic controller(PLC) is a computer system for instrumentation and control (I and C) system of nuclear power plants. PLC consists of various I and C logics in software, including real-time operating system (RTOS). Hence, errors related with RTOS should be detected and eliminated in development processes. Practically, the verification and validation for errors in RTOS is performed in test procedure, in which a lot of tasks for testing are embedded in RTOS and are running under a test environments. But the test process can not be enough to guarantee the safety and reliability of RTOS. Therefore, in this paper, we introduce to applying formal methods with the development of software for the PLC. We particularity apply formal methods to a development of RTOS for PLC, which is a safety critical level. In this development, we use the state charts of I-Logix to specify and verification and model checking to verify the specification
Formal model-based development for safety-critical embedded software
Energy Technology Data Exchange (ETDEWEB)
Kim, Jin Hyun; Choi, Jin Young [Korea University, seoul (Korea, Republic of)
2005-11-15
Safety-critical embedded software for nuclear I and C system is developed under the safety and reliability regulation. Programmable logic controller(PLC) is a computer system for instrumentation and control (I and C) system of nuclear power plants. PLC consists of various I and C logics in software, including real-time operating system (RTOS). Hence, errors related with RTOS should be detected and eliminated in development processes. Practically, the verification and validation for errors in RTOS is performed in test procedure, in which a lot of tasks for testing are embedded in RTOS and are running under a test environments. But the test process can not be enough to guarantee the safety and reliability of RTOS. Therefore, in this paper, we introduce to applying formal methods with the development of software for the PLC. We particularity apply formal methods to a development of RTOS for PLC, which is a safety critical level. In this development, we use the state charts of I-Logix to specify and verification and model checking to verify the specification.
Maintaining scale as a realiable computational system for criticality safety analysis
International Nuclear Information System (INIS)
Bowmann, S.M.; Parks, C.V.; Martin, S.K.
1995-01-01
Accurate and reliable computational methods are essential for nuclear criticality safety analyses. The SCALE (Standardized Computer Analyses for Licensing Evaluation) computer code system was originally developed at Oak Ridge National Laboratory (ORNL) to enable users to easily set up and perform criticality safety analyses, as well as shielding, depletion, and heat transfer analyses. Over the fifteen-year life of SCALE, the mainstay of the system has been the criticality safety analysis sequences that have featured the KENO-IV and KENO-V.A Monte Carlo codes and the XSDRNPM one-dimensional discrete-ordinates code. The criticality safety analysis sequences provide automated material and problem-dependent resonance processing for each criticality calculation. This report details configuration management which is essential because SCALE consists of more than 25 computer codes (referred to as modules) that share libraries of commonly used subroutines. Changes to a single subroutine in some cases affect almost every module in SCALE exclamation point Controlled access to program source and executables and accurate documentation of modifications are essential to maintaining SCALE as a reliable code system. The modules and subroutine libraries in SCALE are programmed by a staff of approximately ten Code Managers. The SCALE Software Coordinator maintains the SCALE system and is the only person who modifies the production source, executables, and data libraries. All modifications must be authorized by the SCALE Project Leader prior to implementation
Critical safety function guidelines for experimental fusion facilities
International Nuclear Information System (INIS)
Cadwallader, L.C.
1989-01-01
As fusion experiments proceed toward deuterium-tritium operation, more attention is being given to public safety. This paper presents the four classes of functions that fusion experiments must provide to assure safe, stable shutdown and retention of radionuclides. These functions are referred to as critical safety functions (CSFs). Selecting CSFs is an important step in probabilistic risk assessment (PRA). An example of CSF selection and usage for the Compact Ignition Tokamak (CIT) is also presented
Krauesslar, Victoria; Avery, Rachel E; Passmore, Jonathan
2015-01-01
Safety coaching interventions have become a common feature in the safety critical offshore working environments of the North Sea. Whilst the beneficial impact of coaching as an organizational tool has been evidenced, there remains a question specifically over the use of safety coaching and its impact on behavioural change and producing safe working practices. A series of 24 semi-structured interviews were conducted with three groups of experts in the offshore industry: safety coaches, offshore managers and HSE directors. Using a thematic analysis approach, several significant themes were identified across the three expert groups including connecting with and creating safety ownership in the individual, personal significance and humanisation, ingraining safety and assessing and measuring a safety coach's competence. Results suggest clear utility of safety coaching when applied by safety coaches with appropriate coach training and understanding of safety issues in an offshore environment. The current work has found that the use of safety coaching in the safety critical offshore oil and gas industry is a powerful tool in managing and promoting a culture of safety and care.
New enhancements to SCALE for criticality safety analysis
International Nuclear Information System (INIS)
Hollenbach, D.F.; Bowman, S.M.; Petrie, L.M.; Parks, C.V.
1995-01-01
As the speed, available memory, and reliability of computer hardware increases and the cost decreases, the complexity and usability of computer software will increase, taking advantage of the new hardware capabilities. Computer programs today must be more flexible and user friendly than those of the past. Within available resources, the SCALE staff at Oak Ridge National Laboratory (ORNL) is committed to upgrading its computer codes to keep pace with the current level of technology. This paper examines recent additions and enhancements to the criticality safety analysis sections of the SCALE code package. These recent additions and enhancements made to SCALE can be divided into nine categories: (1) new analytical computer codes, (2) new cross-section libraries, (3) new criticality search sequences, (4) enhanced graphical capabilities, (5) additional KENO enhancements, (6) enhanced resonance processing capabilities, (7) enhanced material information processing capabilities, (8) portability of the SCALE code package, and (9) other minor enhancements, modifications, and corrections to SCALE. Each of these additions and enhancements to the criticality safety analysis capabilities of the SCALE code system are discussed below
Natural Language Interface for Safety Certification of Safety-Critical Software
Denney, Ewen; Fischer, Bernd
2011-01-01
Model-based design and automated code generation are being used increasingly at NASA. The trend is to move beyond simulation and prototyping to actual flight code, particularly in the guidance, navigation, and control domain. However, there are substantial obstacles to more widespread adoption of code generators in such safety-critical domains. Since code generators are typically not qualified, there is no guarantee that their output is correct, and consequently the generated code still needs to be fully tested and certified. The AutoCert generator plug-in supports the certification of automatically generated code by formally verifying that the generated code is free of different safety violations, by constructing an independently verifiable certificate, and by explaining its analysis in a textual form suitable for code reviews.
Site safety requirements for high level waste disposal
International Nuclear Information System (INIS)
Chen Weiming; Wang Ju
2006-01-01
This paper outlines the content, status and trend of site safety requirements of International Atomic Energy Agency, America, France, Sweden, Finland and Japan. Site safety requirements are usually represented as advantageous vis-a-vis disadvantagous conditions, and potential advantage vis-a-vis disadvantage conditions, respectively in aspects of geohydrology, geochemistry, lithology, climate and human intrusion etc. Study framework and steps of site safety requirements for China are discussed under the view of systems science. (authors)
New requirements on safety of nuclear power plants according to the IAEA safety standards
International Nuclear Information System (INIS)
Misak, J.
2005-01-01
In this presentation author presents new requirements on safety of nuclear power plants according to the IAEA safety standards. It is concluded that: - New set of IAEA Safety Standards is close to completion: around 40 standards for NPPs; - Different interpretation of IAEA Safety Standards at present: best world practices instead of previous 'minimum common denominator'; - A number of safety improvements required for NPPs; - Requirements related to BDBAs and severe accidents are the most demanding due to degradation of barriers: hardware modifications and accident management; - Large variety between countries in implementation of accident management programmes: from minimum to major hardware modifications; -Distinction between existing and new NPPs is essential from the point of view of the requirements; WWER 440 reactors have potential to reflect IAEA Safety Standards for existing NPPs; relatively low reactor power offers broader possibilities
Alam, Muhammad Mahtab; Ben Hamida, Elyes
2014-05-23
In this survey a new application paradigm life and safety for critical operations and missions using wearable Wireless Body Area Networks (WBANs) technology is introduced. This paradigm has a vast scope of applications, including disaster management, worker safety in harsh environments such as roadside and building workers, mobile health monitoring, ambient assisted living and many more. It is often the case that during the critical operations and the target conditions, the existing infrastructure is either absent, damaged or overcrowded. In this context, it is envisioned that WBANs will enable the quick deployment of ad-hoc/on-the-fly communication networks to help save many lives and ensuring people's safety. However, to understand the applications more deeply and their specific characteristics and requirements, this survey presents a comprehensive study on the applications scenarios, their context and specific requirements. It explores details of the key enabling standards, existing state-of-the-art research studies, and projects to understand their limitations before realizing aforementioned applications. Application-specific challenges and issues are discussed comprehensively from various perspectives and future research and development directions are highlighted as an inspiration for new innovative solutions. To conclude, this survey opens up a good opportunity for companies and research centers to investigate old but still new problems, in the realm of wearable technologies, which are increasingly evolving and getting more and more attention recently.
Critical safety function guidelines for experimental fusion facilities
International Nuclear Information System (INIS)
Cadwallader, L.C.
1989-01-01
As fusion experiments proceed toward deuterium-tritium operation, more attention is being given to public safety. This paper presents the four classes of functions that fusion experiments must provide to assure safe, stable shutdown and retention of radionuclides. These functions are referred to as critical safety functions (CSFs). Selecting CSFs is an important step in probabilistic risk assessment (PRA). An example of CSF selection and usage for the Compact Ignition Tokamak (CIT) is also presented. 10 refs., 6 figs
Kuo, Calvin C; Robb, William J
2013-06-01
The prevention of medical and surgical harm remains an important public health problem despite increased awareness and implementation of safety programs. Successful introduction and maintenance of surgical safety programs require both surgeon leadership and collaborative surgeon-hospital alignment. Documentation of success of such surgical safety programs in orthopaedic practice is limited. We describe the scope of orthopaedic surgical patient safety issues, define critical elements of orthopaedic surgical safety, and outline leadership roles for orthopaedic surgeons needed to establish and sustain a culture of safety in contemporary healthcare systems. We identified the most common causes of preventable surgical harm based on adverse and sentinel surgical events reported to The Joint Commission. A comprehensive literature review through a MEDLINE(®) database search (January 1982 through April 2012) to identify pertinent orthopaedic surgical safety articles found 14 articles. Where gaps in orthopaedic literature were identified, the review was supplemented by 22 nonorthopaedic surgical references. Our final review included 36 articles. Six important surgical safety program elements needed to eliminate preventable surgical harm were identified: (1) effective surgical team communication, (2) proper informed consent, (3) implementation and regular use of surgical checklists, (4) proper surgical site/procedure identification, (5) reduction of surgical team distractions, and (6) routine surgical data collection and analysis to improve the safety and quality of surgical patient care. Successful surgical safety programs require a culture of safety supported by all six key surgical safety program elements, active surgeon champions, and collaborative hospital and/or administrative support designed to enhance surgical safety and improve surgical patient outcomes. Further research measuring improvements from such surgical safety systems in orthopaedic care is needed.
Classification for Safety-Critical Car-Cyclist Scenarios Using Machine Learning
Cara, I.; Gelder, E.D.
2015-01-01
The number of fatal car-cyclist accidents is increasing. Advanced Driver Assistance Systems (ADAS) can improve the safety of cyclists, but they need to be tested with realistic safety-critical car-cyclist scenarios. In order to store only relevant scenarios, an online classification algorithm is
Development and experimental qualification of the new safety-criticality CRISTAL package
International Nuclear Information System (INIS)
Mattera, Ch.
1998-11-01
This thesis is concerned with Criticality-Safety studies related to the French Nuclear Fuel Cycle. We first describe the steps in the nuclear fuel cycle and the specific characteristics of these studies compared with those performed in Reactor Physics. In order to respond to the future requirements of the French Nuclear Program, we have developed a new package CRISTAL based on a recent cross sections library (CEA 93) and the newest accurate codes (APOLLO 2, MORET 4, TRIPOLI 4). The CRISTAL system includes two calculations routes: a design route which will be used by French Industry (COGEMA/SGN) and a reference route. To transfer this package to the French industry, we have elaborated calculation schemes for fissile solutions, dissolver media, transport casks and storage pools. Afterwards, these schemes have been used for the CRISTAL experimental validation. We have also contributed to the CRISTAL experimental database by reevaluating a French storage pool experiment: the CRISTO II experiment. This revaluation has been submitted to the OECD working group in order that this experiment can be used by international criticality safety engineers to validate calculations methods. This work represents a large contribution to the recommendation of accurate calculation schemes and to the experimental validation of the CRISTAL package. These studies came up to the French Industry expectations. (author)
Development and experimental testing of the new safety-criticality Cristal package
International Nuclear Information System (INIS)
Mattera, Ch.
1998-01-01
This thesis is concerned with Criticality-Safety studies related to the French Nuclear Fuel Cycle. We first describe the steps in the nuclear fuel cycle and the specific characteristics of these studies compared with those performed in Reactor Physics. In order to respond to the future requirements of the French Nuclear Program, we have developed a new package CRISTAL based on a recent cross sections library (CEA93) and the newest accurate codes (APOLLO2, MORET4, TRIPOLI4). The cristal system includes two calculations routes: a design route which will be used by French Industry (COGEMA/SGN) and a reference route.) To transfer this package to the French industry, we have elaborated calculation schemes for fissile solutions, dissolver media, transport casks and storage pools. Afterwards, these schemes have been used for the CRISTAL experimental validation. We have also contributed to the CRISTAL experimental database by reevaluating a French storage pool experiment: the CRISTO II experiment. This revaluation has been submitted to the OCDE working group in order that this experiment can be used by international criticality safety engineers to validate calculations methods. This work represents a large contribution to the recommendation of accurate calculation schemes and to the experimental validation of the CRISTAL package. These studies came up to the French Industry expectations. (author)
Developing software for safety-critical applications
International Nuclear Information System (INIS)
Chudleigh, M.
1989-01-01
The effective implementation of many safety-critical systems involves microprocessors running software which needs to be of very high integrity. This article describes some of the problems of producing such software and the place of software within the total system. A development strategy is proposed based on three principles: the goal of defect-free development, the use of mathematical formalism, and the use of an independent team for testing. (author)
Supporting Multiprocessors in the Icecap Safety-Critical Java Run-Time Environment
DEFF Research Database (Denmark)
Zhao, Shuai; Wellings, Andy; Korsholm, Stephan Erbs
The current version of the Safety Critical Java (SCJ) specification defines three compliance levels. Level 0 targets single processor programs while Level 1 and 2 can support multiprocessor platforms. Level 1 programs must be fully partitioned but Level 2 programs can also be more globally...... scheduled. As of yet, there is no official Reference Implementation for SCJ. However, the icecap project has produced a Safety-Critical Java Run-time Environment based on the Hardware-near Virtual Machine (HVM). This supports SCJ at all compliance levels and provides an implementation of the safety......-critical Java (javax.safetycritical) package. This is still work-in-progress and lacks certain key features. Among these is the ability to support multiprocessor platforms. In this paper, we explore two possible options to adding multiprocessor support to this environment: the “green thread” and the “native...
Dry critical experiments and analyses performed in support of the Topaz-2 Safety Program
International Nuclear Information System (INIS)
Pelowitz, D.B.; Sapir, J.; Glushkov, E.S.; Ponomarev-Stepnoi, N.N.; Bubelev, V.G.; Kompanietz, G.B.; Krutov, A.M.; Polyakov, D.N.; Loynstev, V.A.
1994-01-01
In December 1991, the Strategic Defense Initiative Organization decided to investigate the possibility of launching a Russian Topaz-2 space nuclear power system. Functional safety requirements developed for the Topaz mission mandated that the reactor remain subcritical when flooded and immersed in water. Initial experiments and analyses performed in Russia and the United States indicated that the reactor could potentially become supercritical in several water- or sand-immersion scenarios. Consequently, a series of critical experiments was performed on the Narciss M-II facility at the Kurchatov Institute to measure the reactivity effects of water and sand immersion, to quantify the effectiveness of reactor modifications proposed to preclude criticality, and to benchmark the calculational methods and nuclear data used in the Topaz-2 safety analyses. In this paper we describe the Narciss M-II experimental configurations along with the associated calculational models and methods. We also present and compare the measured and calculated results for the dry experimental configurations
Dry critical experiments and analyses performed in support of the TOPAZ-2 safety program
International Nuclear Information System (INIS)
Pelowitz, D.B.; Sapir, J.; Glushkov, E.S.; Ponomarev-Stepnoi, N.N.; Bubelev, V.G.; Kompanietz, G.B.; Krutov, A.M.; Polyakov, D.N.; Lobynstev, V.A.
1995-01-01
In December 1991, the Strategic Defense Initiative Organization decided to investigate the possibility of launching a Russian Topaz-2 space nuclear power system. Functional safety requirements developed for the Topaz mission mandated that the reactor remain subcritical when flooded and immersed in water. Initial experiments and analyses performed in Russia and the United States indicated that the reactor could potentially become supercritical in several water- or sand-immersion scenarios. Consequently, a series of critical experiments was performed on the Narciss M-II facility at the Kurchatov Institute to measure the reactivity effects of water and sand immersion, to quantify the effectiveness of reactor modifications proposed to preclude criticality, and to benchmark the calculational methods and nuclear data used in the Topaz-2 safety analyses. In this paper we describe the Narciss M-II experimental configurations along with the associated calculational models and methods. We also present and compare the measured and calculated results for the dry experimental configurations. copyright 1995 American Institute of Physics
Sensitivity and uncertainty analyses applied to criticality safety validation. Volume 2
International Nuclear Information System (INIS)
Broadhead, B.L.; Hopper, C.M.; Parks, C.V.
1999-01-01
This report presents the application of sensitivity and uncertainty (S/U) analysis methodologies developed in Volume 1 to the code/data validation tasks of a criticality safety computational study. Sensitivity and uncertainty analysis methods were first developed for application to fast reactor studies in the 1970s. This work has revitalized and updated the existing S/U computational capabilities such that they can be used as prototypic modules of the SCALE code system, which contains criticality analysis tools currently in use by criticality safety practitioners. After complete development, simplified tools are expected to be released for general use. The methods for application of S/U and generalized linear-least-square methodology (GLLSM) tools to the criticality safety validation procedures were described in Volume 1 of this report. Volume 2 of this report presents the application of these procedures to the validation of criticality safety analyses supporting uranium operations where enrichments are greater than 5 wt %. Specifically, the traditional k eff trending analyses are compared with newly developed k eff trending procedures, utilizing the D and c k coefficients described in Volume 1. These newly developed procedures are applied to a family of postulated systems involving U(11)O 2 fuel, with H/X values ranging from 0--1,000. These analyses produced a series of guidance and recommendations for the general usage of these various techniques. Recommendations for future work are also detailed
Planning the Unplanned Experiment: Assessing the Efficacy of Standards for Safety Critical Software
Graydon, Patrick J.; Holloway, C. Michael
2015-01-01
We need well-founded means of determining whether software is t for use in safety-critical applications. While software in industries such as aviation has an excellent safety record, the fact that software aws have contributed to deaths illustrates the need for justi ably high con dence in software. It is often argued that software is t for safety-critical use because it conforms to a standard for software in safety-critical systems. But little is known about whether such standards `work.' Reliance upon a standard without knowing whether it works is an experiment; without collecting data to assess the standard, this experiment is unplanned. This paper reports on a workshop intended to explore how standards could practicably be assessed. Planning the Unplanned Experiment: Assessing the Ecacy of Standards for Safety Critical Software (AESSCS) was held on 13 May 2014 in conjunction with the European Dependable Computing Conference (EDCC). We summarize and elaborate on the workshop's discussion of the topic, including both the presented positions and the dialogue that ensued.
Therapeutic Plasma Exchange in Critically Ill Children Requiring Intensive Care.
Cortina, Gerard; McRae, Rosemary; Chiletti, Roberto; Butt, Warwick
2018-02-01
To characterize the clinical indications, procedural safety, and outcome of critically ill children requiring therapeutic plasma exchange. Retrospective observational study based on a prospective registry. Tertiary and quaternary referral 30-bed PICU. Forty-eight critically ill children who received therapeutic plasma exchange during an 8-year period (2007-2014) were included in the study. Therapeutic plasma exchange. A total of 48 patients underwent 244 therapeutic plasma exchange sessions. Of those, therapeutic plasma exchange was performed as sole procedure in 193 (79%), in combination with continuous renal replacement therapy in 40 (16.4%) and additional extracorporeal membrane oxygenation in 11 (4.6%) sessions. The most common admission diagnoses were hematologic disorders (30%), solid organ transplantation (20%), neurologic disorders (20%), and rheumatologic disorders (15%). Complications associated with the procedure occurred in 50 (21.2%) therapeutic plasma exchange sessions. Overall, patient survival from ICU was 82%. Although patients requiring therapeutic plasma exchange alone (n = 31; 64%) had a survival rate of 97%, those with additional continuous renal replacement therapy (n = 13; 27%) and extracorporeal membrane oxygenation (n = 4; 8%) had survival rates of 69% and 50%, respectively. Factors associated with increased mortality were lower Pediatric Index of Mortality 2 score, need for mechanical ventilation, higher number of failed organs, and longer ICU stay. Our results indicate that, in specialized centers, therapeutic plasma exchange can be performed relatively safely in critically ill children, alone or in combination with continuous renal replacement therapy and extracorporeal membrane oxygenation. Outcome in children requiring therapeutic plasma exchange alone is excellent. However, survival decreases with the number of failed organs and the need for continuous renal replacement therapy and extracorporeal membrane oxygenation.
International Nuclear Information System (INIS)
Bock, M.; Stuke, M.; Behler, M.
2013-01-01
The validation of a code for criticality safety analysis requires the recalculation of benchmark experiments. The selected benchmark experiments are chosen such that they have properties similar to the application case that has to be assessed. A common source of benchmark experiments is the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments' (ICSBEP Handbook) compiled by the 'International Criticality Safety Benchmark Evaluation Project' (ICSBEP). In order to take full advantage of the information provided by the individual benchmark descriptions for the application case, the recommended procedure is to perform an uncertainty analysis. The latter is based on the uncertainties of experimental results included in most of the benchmark descriptions. They can be performed by means of the Monte Carlo sampling technique. The consideration of uncertainties is also being introduced in the supplementary sheet of DIN 25478 'Application of computer codes in the assessment of criticality safety'. However, for a correct treatment of uncertainties taking into account the individual uncertainties of the benchmark experiments is insufficient. In addition, correlations between benchmark experiments have to be handled correctly. For example, these correlations can arise due to different cases of a benchmark experiment sharing the same components like fuel pins or fissile solutions. Thus, manufacturing tolerances of these components (e.g. diameter of the fuel pellets) have to be considered in a consistent manner in all cases of the benchmark experiment. At the 2012 meeting of the Expert Group on 'Uncertainty Analysis for Criticality Safety Assessment' (UACSA) of the OECD/NEA a benchmark proposal was outlined that aimed for the determination of the impact on benchmark correlations on the estimation of the computational bias of the neutron multiplication factor (k eff ). The analysis presented here is based on this proposal. (orig.)
Cyber Security Threats to Safety-Critical, Space-Based Infrastructures
Johnson, C. W.; Atencia Yepez, A.
2012-01-01
Space-based systems play an important role within national critical infrastructures. They are being integrated into advanced air-traffic management applications, rail signalling systems, energy distribution software etc. Unfortunately, the end users of communications, location sensing and timing applications often fail to understand that these infrastructures are vulnerable to a wide range of security threats. The following pages focus on concerns associated with potential cyber-attacks. These are important because future attacks may invalidate many of the safety assumptions that support the provision of critical space-based services. These safety assumptions are based on standard forms of hazard analysis that ignore cyber-security considerations This is a significant limitation when, for instance, security attacks can simultaneously exploit multiple vulnerabilities in a manner that would never occur without a deliberate enemy seeking to damage space based systems and ground infrastructures. We address this concern through the development of a combined safety and security risk assessment methodology. The aim is to identify attack scenarios that justify the allocation of additional design resources so that safety barriers can be strengthened to increase our resilience against security threats.
International Nuclear Information System (INIS)
Koo, Seo Ryong; Seong, Poong Hyun; Yoo, Jun Beom; Cha, Sung Deok; Youn, Cheong; Han, Hyun Chul
2006-01-01
As the use of digital systems becomes more prevalent, adequate techniques for software specification and analysis have become increasingly important in Nuclear Power Plant (NPP) safety-critical systems. Additionally, the importance of software Verification and Validation (V and V) based on adequate specification has received greater emphasis in view of improving software quality. For thorough V and V of safety-critical systems, V and V should be performed throughout the software lifecycle. However, systematic V and V is difficult as it involves many manual-oriented tasks. Tool support is needed in order to more conveniently perform software V and V. In response, we developed four kinds of Computer Aided Software Engineering (CASE) tools to support system specification for a formal-based analysis according to the software lifecycle. In this work, we achieved optimized integration of each tool. The toolset, NuSEE, is an integrated environment for software specification and V and V for PLC based safety-critical systems. In accordance with the software lifecycle, NuSEE consists of NuSISRT for the concept phase, NuSRS for the requirements phase, NuSDS for the design phase and NuSCM for configuration management. It is believed that after further development our integrated environment will be a unique and promising software specification and analysis toolset that will support the entire software lifecycle for the development of PLC based NPP safety-critical systems
A study to develop the domestic functional requirements of the specific safety systems of CANDU
Energy Technology Data Exchange (ETDEWEB)
Kim, Man Woong [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of); Lee, Jae Young; Park, Kun Chul [Handong Global Univ., Pohang (Korea, Republic of)] (and others)
2003-03-15
The present research has been made to develop and review critically the functional requirements of the specific safety systems of CANDU such as SDS-1, SDS2, ECCS, and containment. Based on R documents for this, a systematic study was made to develop the domestic regulation statements. Also, the conventional laws are carefully reviewed to see the compatibility to CANDU. Also, the safety assessment method for CANDU was studied by reviewing C documents and recommendation of IAEA. Through the present works, the vague policy in the CANDU safety regulation is cleaning up in a systematic form and a new frame to measure the objective risk of nuclear power plants was developed.
A study to develop the domestic functional requirements of the specific safety systems of CANDU
Energy Technology Data Exchange (ETDEWEB)
Kim, Man Woong; Lee, Jae Young; Bang, Kwang Hyun [Handong Global Univ., Pohang (Korea, Republic of)] (and others)
2001-03-15
The present research has been made to develop and review critically the functional requirements of the specific safety systems of CANDU such as SOS-1, SOS-2, ECCS and containment. Based on R documents for this, a systematic study was made to develop the domestic regulation statements. Also, the conventional laws are carefully reviewed to see the compatibility to CANDU. Also, the safety assessment method for CANDU was studied by reviewing C documents and recommendation of IAEA. Through the present works, the vague policy in the CANDU safety regulation is cleaning up in a systematic form and a new frame to measure the objective risk of nuclear power plants was developed.
Criticality Safety Problems Related to Storage of Highly Active Liquid Waste
International Nuclear Information System (INIS)
Amin, E.
1999-01-01
The geometries of liquid waste storage tanks are not generally safe against criticality. Normally, this does not cause problems as fissile materials exist in nitric acid solution only as depleted uranium or in insignificant concentration of the originally reprocessed inventory of plutonium. However, if sedimentation of solid particles would occur, the deposited material would cause criticality safety problems. Particularly, non-horizontal installation of the storage tanks would increase the Eigen value. The effect of the storage tank inclination and the presence of transplutonium elements on the criticality safety are investigated using the NCNSRC code packages. The results are compared well with a similar German published results
10 CFR 76.87 - Technical safety requirements.
2010-01-01
...: (1) Effects of natural phenomena; (2) Building and process ventilation and offgas; (3) Criticality...; (8) Environmental protection; (9) Packaging and transporting nuclear materials; (10) Accident analysis; (11) Chemical safety; (12) Sharing of facilities, structures, systems and components; (13...
Criticality safety philosophy for the Sellafield MOX plant
International Nuclear Information System (INIS)
Edge, Jane; Gulliford, Jim
2003-01-01
The Sellafield MOX Plant (SMP) has been operational since 2001, blending plutonium dioxide from THORP reprocessing operations, with uranium dioxide to produce Mixed Oxide (MOX) fuel elements. In handling the quantities of fuel associated with a commercial fuel fabrication plant, it is necessary to impose criticality controls. Plutonium dioxide (PuO 2 ), uranium dioxide (UO 2 ) and recycled MOX are mixed together in batches. An Engineered Protection System (EPS) prevents the production of MOX powder in excess of 20w/o Pu(fissile)/(Pu+U), achieved through the combination of a weight-based' system and a diverse 'neutron monitoring' radiometric system. The 'neutron monitoring' component of the EPS determines the fissile enrichment of the batch of MOX powder, based on pessimistic isotopic requirements of the PuO 2 feedstock powder. Guaranteeing the maximum MOX enrichment of 20w/o Pu(fissile)/(Pu + U) at an early stage of the fuel manufacturing process enables the criticality safety assessor to demonstrate that normal operations are deterministically safe. This paper describes in detail the EPS at the front end of plant and the engineered and operational protection in downstream areas. In addition plant operational experience in producing the first fuel assemblies is discussed. (author)
Process management - critical safety issues with focus on risk management
International Nuclear Information System (INIS)
Sanne, Johan M.
2005-12-01
Organizational changes focused on process orientation are taking place among Swedish nuclear power plants, aiming at improving the operation. The Swedish Nuclear Power Inspectorate has identified a need for increased knowledge within the area for its regulatory activities. In order to analyze what process orientation imply for nuclear power plant safety a number of questions must be asked: 1. How is safety in nuclear power production created currently? What significance does the functional organization play? 2. How can organizational forms be analysed? What consequences does quality management have for work and for the enterprise? 3. Why should nuclear power plants be process oriented? Who are the customers and what are their customer values? Which customers are expected to contribute from process orientation? 4. What can one learn from process orientation in other safety critical systems? What is the effect on those features that currently create safety? 5. Could customer values increase for one customer without decreasing for other customers? What is the relationship between economic and safety interests from an increased process orientation? The deregulation of the electricity market have caused an interest in increased economic efficiency, which is the motivation for the interest in process orientation. among other means. It is the nuclear power plants' owners and the distributors (often the same corporations) that have the strongest interest in process orientation. If the functional organization and associated practices are decomposed, the prerequisites of the risk management regime changes, perhaps deteriorating its functionality. When nuclear power operators consider the introduction of process orientation, the Nuclear Power Inspectorate should require that 1. The operators perform a risk analysis beforehand concerning the potential consequences that process orientation might convey: the analysis should contain a model specifying how safety is currently
[Storage of plant protection products in farms: minimum safety requirements].
Dutto, Moreno; Alfonzo, Santo; Rubbiani, Maristella
2012-01-01
Failure to comply with requirements for proper storage and use of pesticides in farms can be extremely hazardous and the risk of accidents involving farm workers, other persons and even animals is high. There are still wide differences in the interpretation of the concept of "securing or making safe", by workers in this sector. One of the critical points detected, particularly in the fruit sector, is the establishment of an adequate storage site for plant protection products. The definition of "safe storage of pesticides" is still unclear despite the recent enactment of Legislative Decree 81/2008 regulating health and work safety in Italy. In addition, there are no national guidelines setting clear minimum criteria for storage of plant protection products in farms. The authors, on the basis of their professional experience and through analysis of recent legislation, establish certain minimum safety standards for storage of pesticides in farms.
Single parameter controls for nuclear criticality safety at the Oak Ridge Y-12 Plant
International Nuclear Information System (INIS)
Baker, J.S.; Peek, W.M.
1995-01-01
At the Oak Ridge Y-12 Plant, there are numerous situations in which nuclear criticality safety must be assured and subcriticality demonstrated by some method other than the straightforward use of the double contingency principle. Some cases are cited, and the criticality safety evaluation of contaminated combustible waste collectors is considered in detail. The criticality safety evaluation for combustible collectors is based on applying one very good control to the one controllable parameter. Safety can only be defended when the contingency of excess density is limited to a credible value based on process knowledge. No reasonable single failure is found that will result in a criticality accident. The historically accepted viewpoint is that this meets double contingency, even though there are not two independent controls on the single parameter of interest
Meeting the maglev system's safety requirements
Energy Technology Data Exchange (ETDEWEB)
Pierick, K
1983-12-01
The author shows how the safety requirements of the maglev track system derive from the general legal conditions for the safety of tracked transport. It is described how their compliance beyond the so-called ''development-accompanying'' and ''acceptance-preparatory'' safety work can be assured for the Transrapid test layout (TVE) now building in Emsland and also for later application as public transport system in Germany within the meaning of the General Railway Act.
Generic Safety Requirements for Developing Safe Insulin Pump Software
Zhang, Yi; Jetley, Raoul; Jones, Paul L; Ray, Arnab
2011-01-01
Background The authors previously introduced a highly abstract generic insulin infusion pump (GIIP) model that identified common features and hazards shared by most insulin pumps on the market. The aim of this article is to extend our previous work on the GIIP model by articulating safety requirements that address the identified GIIP hazards. These safety requirements can be validated by manufacturers, and may ultimately serve as a safety reference for insulin pump software. Together, these two publications can serve as a basis for discussing insulin pump safety in the diabetes community. Methods In our previous work, we established a generic insulin pump architecture that abstracts functions common to many insulin pumps currently on the market and near-future pump designs. We then carried out a preliminary hazard analysis based on this architecture that included consultations with many domain experts. Further consultation with domain experts resulted in the safety requirements used in the modeling work presented in this article. Results Generic safety requirements for the GIIP model are presented, as appropriate, in parameterized format to accommodate clinical practices or specific insulin pump criteria important to safe device performance. Conclusions We believe that there is considerable value in having the diabetes, academic, and manufacturing communities consider and discuss these generic safety requirements. We hope that the communities will extend and revise them, make them more representative and comprehensive, experiment with them, and use them as a means for assessing the safety of insulin pump software designs. One potential use of these requirements is to integrate them into model-based engineering (MBE) software development methods. We believe, based on our experiences, that implementing safety requirements using MBE methods holds promise in reducing design/implementation flaws in insulin pump development and evolutionary processes, therefore improving
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
78 FR 46560 - Pipeline Safety: Class Location Requirements
2013-08-01
... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration 49 CFR Part... class location requirements for gas transmission pipelines. Section 5 of the Pipeline Safety, Regulatory... and, with respect to gas transmission pipeline facilities, whether applying IMP requirements to...
Impact of Fuel Failure on Criticality Safety of Used Nuclear Fuel
International Nuclear Information System (INIS)
Marshall, William J.; Wagner, John C.
2012-01-01
Commercial used nuclear fuel (UNF) in the United States is expected to remain in storage for considerably longer periods than originally intended (e.g., 45 GWd/t) may increase the potential for fuel failure during normal and accident conditions involving storage and transportation. Fuel failure, depending on the severity, can result in changes to the geometric configuration of the fuel, which has safety and regulatory implications. The likelihood and extent of fuel reconfiguration and its impact on the safety of the UNF is not well understood. The objective of this work is to assess and quantify the impact of fuel reconfiguration due to fuel failure on criticality safety of UNF in storage and transportation casks. This effort is primarily motivated by concerns related to the potential for fuel degradation during ES periods and transportation following ES. The criticality analyses consider representative UNF designs and cask systems and a range of fuel enrichments, burnups, and cooling times. The various failed-fuel configurations considered are designed to bound the anticipated effects of individual rod and general cladding failure, fuel rod deformation, loss of neutron absorber materials, degradation of canister internals, and gross assembly failure. The results quantify the potential impact on criticality safety associated with fuel reconfiguration and may be used to guide future research, design, and regulatory activities. Although it can be concluded that the criticality safety impacts of fuel reconfiguration during transportation subsequent to ES are manageable, the results indicate that certain configurations can result in a large increase in the effective neutron multiplication factor, k eff . Future work to inform decision making relative to which configurations are credible, and therefore need to be considered in a safety evaluation, is recommended.
Optimal Braking Patterns and Forces in Autonomous Safety-Critical Maneuvers
Fors, Victor
2018-01-01
The trend of more advanced driver-assistance features and the development toward autonomous vehicles enable new possibilities in the area of active safety. With more information available in the vehicle about the surrounding traffic and the road ahead, there is the possibility of improved active-safety systems that make use of this information for stability control in safety-critical maneuvers. Such a system could adaptively make a trade-off between controlling the longitudinal, lateral, and ...
Requirements for reflection in the critical care environment
Directory of Open Access Journals (Sweden)
Celia J. Filmalter
2015-03-01
Full Text Available Background: Reflection is recognised as an important method for practice development. The importance of reflection is well documented in the literature, but the requirements for reflection remain unclear. Objectives: To explore and describe the requirements for reflection in the critical care environment as viewed by educators of qualified critical care nurses. Method: A focus group interview was conducted to explore and describe the views of educators of qualified critical care nurses regarding requirements for reflection in the critical care environment. Results: The themes that emerged from the focus group were buy-in from stakeholders –management, facilitators and critical care nurses, and the need to create an environment where reflection can occur. Conclusion: Critical care nurses should be allowed time to reflect on their practice and be supported by peers as well as a facilitator in a non-intimidating way to promote emancipatorypractice development.
Energy Technology Data Exchange (ETDEWEB)
J. Blair Briggs; Lori Scott; Yolanda Rugama; Enrico Sartori
2009-09-01
High-quality integral benchmark experiments have always been a priority for criticality safety. However, interest in integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties accelerate to meet the demands of future criticality safety needs to support next generation reactor and advanced fuel cycle concepts. The importance of drawing upon existing benchmark data is becoming more apparent because of dwindling availability of critical facilities worldwide and the high cost of performing new experiments. Integral benchmark data from the International Handbook of Evaluated Criticality Safety Benchmark Experiments and the International Handbook of Reactor Physics Benchmark Experiments are widely used. Benchmark data have been added to these two handbooks since the last Nuclear Criticality Safety Division Topical Meeting in Knoxville, Tennessee (September 2005). This paper highlights these additions.
International Nuclear Information System (INIS)
Briggs, J. B.; Scott, L.; Rugama, Y.; Sartori, E.
2009-01-01
High-quality integral benchmark experiments have always been a priority for criticality safety. However, interest in integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties accelerate to meet the demands of future criticality safety needs to support next generation reactor and advanced fuel cycle concepts. The importance of drawing upon existing benchmark data is becoming more apparent because of dwindling availability of critical facilities worldwide and the high cost of performing new experiments. Integral benchmark data from the International Handbook of Evaluated Criticality Safety Benchmark Experiments and the International Handbook of Reactor Physics Benchmark Experiments are widely used. Benchmark data have been added to these two handbooks since the last Nuclear Criticality Safety Division Topical Meeting in Knoxville, Tennessee (September 2005). This paper highlights these additions. (authors)
International Nuclear Information System (INIS)
Briggs, J. Blair; Scott, Lori; Rugama, Yolanda; Sartori, Enrico
2009-01-01
High-quality integral benchmark experiments have always been a priority for criticality safety. However, interest in integral benchmark data is increasing as efforts to quantify and reduce calculational uncertainties accelerate to meet the demands of future criticality safety needs to support next generation reactor and advanced fuel cycle concepts. The importance of drawing upon existing benchmark data is becoming more apparent because of dwindling availability of critical facilities worldwide and the high cost of performing new experiments. Integral benchmark data from the International Handbook of Evaluated Criticality Safety Benchmark Experiments and the International Handbook of Reactor Physics Benchmark Experiments are widely used. Benchmark data have been added to these two handbooks since the last Nuclear Criticality Safety Division Topical Meeting in Knoxville, Tennessee (September 2005). This paper highlights these additions.
CSER 94-012: Criticality safety evaluation report for 340 Facility
International Nuclear Information System (INIS)
Altschuler, S.J.
1995-01-01
This Criticality Safety Evaluation Report (CSER) covers the 340 Facility which acts as a collecting point for liquid and solid waste from various facilities in the 300 Area. Criticality safety is achieved by controlling the amount and concentration of the fissionable material sent to the 340 Facility from the originating facilities in the 300 Area, a method similar to that used elsewhere at Hanford for the waste tank farms. Unlike those, however, the waste received at the 340 Facility will be far less radioactive. It is concluded that present operations meet the two contingency criterion. The facility will still be safely subcritical even after two independent and concurrent failures (either of equipment or administrative controls). The solid waste storage and liquid waste will be managed separately. The solid waste storage area is classified as exempt because it contains less than 15 grams of fissionable materials. The Radioactive Liquid Waste System is classified as isolated because it contains less than one third of a minimum critical mass. The criticality safety of the 340 Facility devoted to the Radioactive Liquid Waste System (RLWS) is assured by the form and concentration of the fissile material and could also be classified as a limited control facility. However, the 340 Facility has been operated as an isolated facility which results in a more conservative limit
American National Standards and the DOE - A cooperative effort to promote nuclear criticality safety
International Nuclear Information System (INIS)
Rothleder, B.M.
1996-01-01
The U.S. Department of Energy's (DOE's) new criticality safety order, DOE Order 420.1 (open-quotes Facility Safety,close quotes October 13, 1995), Sec. 4.3 (open-quotes Nuclear Criticality Safetyclose quotes), invokes, as an integral part, 12 appropriate American National Standards Institute/American Nuclear Society (ANSI/ANS) Series-8 standards for nuclear criticality safety, but with modifications. (The order that 420.1/4.3 replaced also invoked some ANSI/ANS Series-8 standards.) These modifications include DOE operation-specific exceptions to the standards and elaborations on some of the wording in the standards
SCALE system cross-section validation for criticality safety analysis
International Nuclear Information System (INIS)
Hathout, A.M.; Westfall, R.M.; Dodds, H.L. Jr.
1980-01-01
The purpose of this study is to test selected data from three cross-section libraries for use in the criticality safety analysis of UO 2 fuel rod lattices. The libraries, which are distributed with the SCALE system, are used to analyze potential criticality problems which could arise in the industrial fuel cycle for PWR and BWR reactors. Fuel lattice criticality problems could occur in pool storage, dry storage with accidental moderation, shearing and dissolution of irradiated elements, and in fuel transport and storage due to inadequate packing and shipping cask design. The data were tested by using the SCALE system to analyze 25 recently performed critical experiments
14 CFR 417.121 - Safety critical preflight operations.
2010-01-01
... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Safety critical preflight operations. 417.121 Section 417.121 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION... surveillance. A launch operator must implement its hazard area surveillance and clearance plan, of § 417.111(j...
Private Memory Allocation Analysis for Safety-Critical Java
DEFF Research Database (Denmark)
Dalsgaard, Andreas E.; Hansen, René Rydhof; Schoeberl, Martin
2012-01-01
Safety-critical Java (SCJ) avoids garbage collection and uses a scope based memory model. This memory model is based on a restricted version of RTSJ [2] style scopes. The scopes form a clear hierarchy with different lifetimes. Therefore, references between objects in different scopes are only...
Chip-Multiprocessor Hardware Locks for Safety-Critical Java
DEFF Research Database (Denmark)
Strøm, Torur Biskopstø; Puffitsch, Wolfgang; Schoeberl, Martin
2013-01-01
and may void a task set's schedulability. In this paper we present a hardware locking mechanism to reduce the synchronization overhead. The solution is implemented for the chip-multiprocessor version of the Java Optimized Processor in the context of safety-critical Java. The implementation is compared...
Criticality safety validation of MCNP5 using continuous energy libraries
International Nuclear Information System (INIS)
Salome, Jean A.D.; Pereira, Claubia; Assuncao, Jonathan B.A.; Veloso, Maria Auxiliadora F.; Costa, Antonella L.; Silva, Clarysson A.M. da
2013-01-01
The study of subcritical systems is very important in the design, installation and operation of various devices, mainly nuclear reactors and power plants. The information generated by these systems guide the decisions to be taken in the executive project, the economic viability and the safety measures to be employed in a nuclear facility. Simulating some experiments from the International Handbook of Evaluated Criticality Safety Benchmark Experiments, the code MCNP5 was validated to nuclear criticality analysis. Its continuous libraries were used. The average values and standard deviation (SD) were evaluated. The results obtained with the code are very similar to the values obtained by the benchmark experiments. (author)
International standardization of safety requirements for fast reactors
International Nuclear Information System (INIS)
2011-06-01
Japan Atomic Energy Agency (JAEA) is conducting the FaCT (Fast Reactor Cycle Technology Development) project in cooperation with Japan Atomic Power Company (JAPC) and Mitsubishi FBR systems inc. (MFBR), where an advanced loop-type fast reactor named JSFR (Japan Sodium-cooled Fast Reactor) is being developed. It is important to develop software technologies (a safety guideline, safety design criteria, safety design standards etc.) of FBRs as well as hardware ones (a reactor plant itself) in order to address prospective worldwide utilization of FBR technology. Therefore, it is expected to establish a rational safety guideline applicable to the JSFR and harmonized with national nuclear-safety regulations as well, including Japan, the United States and the European Union. This report presents domestic and international status of safety guideline development for sodium-cooled fast reactors (SFRs), results of comparative study for safety requirements provided in existing documents and a proposal for safety requirements of future SFRs with a roadmap for their refinement and worldwide utilization. (author)
Finite test sets development method for test execution of safety critical software
International Nuclear Information System (INIS)
Shin, Sung Min; Kim, Hee Eun; Kang, Hyun Gook; Lee, Sung Jiun
2014-01-01
The V and V method has been utilized for this safety critical software, while SRGM has difficulties because of lack of failure occurrence data on developing phase. For the safety critical software, however, failure data cannot be gathered after installation in real plant when we consider the severe consequence. Therefore, to complement the V and V method, the test-based method need to be developed. Some studies on test-based reliability quantification method for safety critical software have been conducted in nuclear field. These studies provide useful guidance on generating test sets. An important concept of the guidance is that the test sets represent 'trajectories' (a series of successive values for the input variables of a program that occur during the operation of the software over time) in the space of inputs to the software.. Actually, the inputs to the software depends on the state of plant at that time, and these inputs form a new internal state of the software by changing values of some variables. In other words, internal state of the software at specific timing depends on the history of past inputs. Here the internal state of the software which can be changed by past inputs is named as Context of Software (CoS). In a certain CoS, a software failure occurs when a fault is triggered by some inputs. To cover the failure occurrence mechanism of a software, preceding researches insist that the inputs should be a trajectory form. However, in this approach, there are two critical problems. One is the length of the trajectory input. Input trajectory should long enough to cover failure mechanism, but the enough length is not clear. What is worse, to cover some accident scenario, one set of input should represent dozen hours of successive values. The other problem is number of tests needed. To satisfy a target reliability with reasonable confidence level, very large number of test sets are required. Development of this number of test sets is a herculean
Safety design guides for seismic requirements for CANDU 9
International Nuclear Information System (INIS)
Lee, Duk Su; Chang, Woo Hyun; Lee, Nam Young; A. C. D. Wright
1996-03-01
This safety design guide for seismic requirements for CANDU 9 describes the seismic design philosophy, defines the applicable earthquakes and identifies the structures and systems requiring seismic qualification to ensure that the essential safety function can be adequately satisfied following earthquake. The detailed requirements for structures, systems and components which must be seismically qualified are specified in the Appendix. The change status of the regulatory requirements, code and standards should be traced and this safety design guide shall be updated accordingly. 1 fig., (Author) .new
International Nuclear Information System (INIS)
Shi Yongqian; Zhu Qingfu; Hu Dingsheng; He Tao; Yao Shigui; Lin Shenghuo
2004-01-01
The paper gives experiment theory and experiment method of neutron source multiplication method for site measurement technology in the nuclear critical safety. The measured parameter by source multiplication method actually is a sub-critical with source neutron effective multiplication factor k s , but not the neutron effective multiplication factor k eff . The experiment research has been done on the uranium solution nuclear critical safety experiment assembly. The k s of different sub-criticality is measured by neutron source multiplication experiment method, and k eff of different sub-criticality, the reactivity coefficient of unit solution level, is first measured by period method, and then multiplied by difference of critical solution level and sub-critical solution level and obtained the reactivity of sub-critical solution level. The k eff finally can be extracted from reactivity formula. The effect on the nuclear critical safety and different between k eff and k s are discussed
Disposal of Radioactive Waste. Specific Safety Requirements (Spanish Edition)
International Nuclear Information System (INIS)
2012-01-01
This Safety Requirements publication applies to the disposal of radioactive waste of all types by means of emplacement in designed disposal facilities, subject to the necessary limitations and controls being placed on the disposal of the waste and on the development, operation and closure of facilities. The classification of radioactive waste is discussed. This Safety Requirements publication establishes requirements to provide assurance of the radiation safety of the disposal of radioactive waste, in the operation of a disposal facility and especially after its closure. The fundamental safety objective is to protect people and the environment from harmful effects of ionizing radiation. This is achieved by setting requirements on the site selection and evaluation and design of a disposal facility, and on its construction, operation and closure, including organizational and regulatory requirements.
Fire safety requirements for electrical cables towards nuclear reactor safety
International Nuclear Information System (INIS)
Raju, M.R.
2002-01-01
Full text: Electrical power supply forms a very important part of any nuclear reactor. Power supplies have been categorized in to class I, II, III and IV from reliability point. The safety related equipment are provided with highly reliable power supply to achieve the safety of very high order. Vast network of cables in a nuclear reactor are grouped and segregated to ensure availability of power to at least one group under all anticipated occurrences. Since fire can result in failures leading to unavailability of power caused by common cause, both passive and active fire protection methods are adopted in addition to fire detection system. The paper describes the requirement for passive fire protection to electrical cables viz. fire barrier and fire breaks. The paper gives an account of the tests required to standardize the products. Fire safety implementation for cables in research reactors is described
Safety analysis of the Los Alamos critical experiments facility
International Nuclear Information System (INIS)
Paxton, H.C.
1975-10-01
The safety of Pajarito Site critical assembly operations depends upon protection built into the facility, upon knowledgeable personnel, and upon good practice as defined by operating procedures and experimental plans. Distance, supplemented by shielding in some cases, would protect personnel against an extreme accident generating 10 19 fissions. During the facility's 28-year history, the direct cost of criticality accidents has translated to a risk of less than $200 per year
Criticality safety benchmarking of PASC-3 and ECNJEF1.1
International Nuclear Information System (INIS)
Li, J.
1992-09-01
To validate the code system PASC-3 and the multigroup cross section library ECNJEF1.1 on various applications many benchmarks are required. This report presents the results of critically safety benchmarking for five calculational and four experimental benchmarks. These benchmarks are related to the transport package of fissile materials such as spent fuel. The fissile nuclides in these benchmarks are 235 U and 239 Pu. The modules of PASC-3 which have been used for the calculations are BONAMI, NITAWL and KENO.5A. The final results for the experimental benchmarks do agree well with experimental data. For the calculational benchmarks the results presented here are in reasonable agreement with the results from other investigations. (author). 8 refs.; 20 figs.; 5 tabs
Analysing context-dependent deviations in interacting with safety-critical systems
International Nuclear Information System (INIS)
Paterno, Fabio; Santoro, Carmen
2006-01-01
Mobile technology is penetrating many areas of human life. This implies that the context of use can vary in many respects. We present a method that aims to support designers in managing the complex design space when considering applications with varying contexts and help them to identify solutions that support users in performing their activities while preserving usability and safety. The method is a novel combination of an analysis of both potential deviations in task performance and most suitable information representations based on distributed cognition. The originality of the contribution is in providing a conceptual tool for better understanding the impact of context of use on user interaction in safety-critical domains. In order to present our approach we provide an example in which the implications of introducing new support through mobile devices in a safety-critical system are identified and analysed in terms of potential hazards
Overview of the activities of the OECD/NEA/NSC working party on nuclear criticality safety
International Nuclear Information System (INIS)
Nouri, A.; Blomquist, R.; Bradyraap, M.; Briggs, B.; Cousinou, P.; Nomura, Y.; Weber, W.
2003-01-01
The OECD Nuclear Energy Agency (NEA) started dealing with criticality-safety related subjects back in the seventies. In the mid-nineties, several activities related to criticality-safety were grouped together into the Working Party on Nuclear Criticality Safety. This working party has since been operating and reporting to the Nuclear Science Committee. Six expert groups co-ordinate various activities ranging from experimental evaluations to code and data inter-comparisons for the study of static and transient criticality behaviours. The paper describes current activities performed in this framework and the achievements of the various expert groups. (author)
The main requirements of the International Basic Safety Standards
International Nuclear Information System (INIS)
Webb, G.A.M.
1998-01-01
The main requirements of the new international basic safety standards are discussed, including such topics as health effects of ionizing radiations, the revision of basic safety standards, the requirements for radiation protection practices, the requirements for intervention,and the field of regulatory infrastructures. (A.K.)
Real-time software use in nuclear materials handling criticality safety control
International Nuclear Information System (INIS)
Huang, S.; Lappa, D.; Chiao, T.; Parrish, C.; Carlson, R.; Lewis, J.; Shikany, D.; Woo, H.
1997-01-01
This paper addresses the use of real-time software to assist handlers of fissionable nuclear material. We focus specifically on the issue of workstation mass limits, and the need for handlers to be aware of, and check against, those mass limits during material transfers. Here ''mass limits'' generally refer to criticality safety mass limits; however, in some instances, workstation mass limits for some materials may be governed by considerations other than criticality, e.g., fire or release consequence limitation. As a case study, we provide a simplified reliability comparison of the use of a manual two handler system with a software-assisted two handler system. We identify the interface points between software and handlers that are relevant to criticality safety
Proceedings of the Nuclear Criticality Technology and Safety Project Workshop
Energy Technology Data Exchange (ETDEWEB)
Sanchez, R.G. [comp.
1994-01-01
This report is the proceedings of the annual Nuclear Criticality Technology and Safety Project (NCTSP) Workshop held in Monterey, California, on April 16--28, 1993. The NCTSP was sponsored by the Department of Energy and organized by the Los Alamos Critical Experiments Facility. The report is divided into six sections reflecting the sessions outlined on the workshop agenda.
Proceedings of the Nuclear Criticality Technology and Safety Project Workshop
International Nuclear Information System (INIS)
Sanchez, R.G.
1994-01-01
This report is the proceedings of the annual Nuclear Criticality Technology and Safety Project (NCTSP) Workshop held in Monterey, California, on April 16--28, 1993. The NCTSP was sponsored by the Department of Energy and organized by the Los Alamos Critical Experiments Facility. The report is divided into six sections reflecting the sessions outlined on the workshop agenda
New developments enhancing MCNP for criticality safety
International Nuclear Information System (INIS)
Hendricks, J.S.; McKinney, G.W.; Forster, R.A.
1993-01-01
Since the early 80's MCNP has had three estimates of k eff : collision, absorption, and track length. MCNP has also had collision and absorption estimators of removal lifetime. These are calculated for every cycle and are averaged over the cycles as simple averages and covariance weighted averages. Correlation coefficients between estimators are also calculated. These criticality estimators are all in addition to the extensive summary information and tally edits used in shielding and other problems. A number of significant new developments have been made to enhance the MCNP Monte Carlo radiation transport code for criticality safety applications. These are available in the newly released MCNP4A version of the code
International Nuclear Information System (INIS)
Thomauske, B.
2008-01-01
The German Federal Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU) on August 12, 2008 published a July 29, 2008 draft of the ''Safety Requirements to Be Met in Final Storage of Heat-producing Radioactive Waste.'' As announced by the BMU, these safety requirements are to bring up to the state of the art the safety criteria of 1983. Over a couple of years, efforts had been made to adapt the criteria to the internationally accepted standard as demanded by the Advisory Committees on Reactor Safeguards (RSK) and Radiation Protection (SSK). The main changes made by the BMU are the introduction of a phased procedure in building repositories. A phased plans approval procedure under the Atomic Energy Act has been foreseen by the Ministry for this purpose. In addition, the draft provides for the introduction of a risk-based goal of protection. To ensure retrievability of the waste, the casks are to have a demonstrated service life of 500 years. The BMU draft safety requirements are unable to bring the safety criteria of 1983 up to the current state of the art. Here are the key points of criticism: - A risk-based goal of protection is introduced. The yardstick to be applied is to be defined in a guideline yet to be elaborated. As a consequence, the draft lacks substance. - As in licensing of nuclear facilities, the licensing procedure provides for a phased plans approval procedure for exploration. This analogy does not exist, as exploration is not the first phase of the plant to be built but a measure which is a precondition for obtaining a permit for construction and operation. - The information contained in the draft indicates that, contrary to international recommendations, it tightens the goal of protection by more than one order of magnitude. - The requirements to be met by the casks because of retrievability impose constraints on solutions optimized for safety in emplacement technology. - The risk-based approach is not mature and is
A study on methodologies for assessing safety critical network's risk impact on Nuclear Power Plant
International Nuclear Information System (INIS)
Lim, T. J.; Lee, H. J.; Park, S. K.; Seo, S. J.
2006-08-01
The objectives of this project is to investigate and study existing reliability analysis techniques for communication networks in order to develop reliability analysis models for Nuclear Power Plant's safety-critical networks. It is necessary to make a comprehensive survey of current methodologies for communication network reliability. Major outputs of the first year study are design characteristics of safety-critical communication networks, efficient algorithms for quantifying reliability of communication networks, and preliminary models for assessing reliability of safety-critical communication networks
Directory of Open Access Journals (Sweden)
Christiaan G. Joubert
2017-04-01
Full Text Available Background: Motivation for this study was found in concern expressed by civil aviation organisations that specialists in the air navigation services provider sector require appropriate and beneficial organisational leadership to encourage, enable and manage transformation within this highly structured setting. Also, academic research puts emphasis on a need for investigations of the roles, expectations and requirements of followers in the leadership–followership relationship. Followers’ experiences and expectations of leadership behaviours in an air navigation service provider (ANSP organisation were investigated and served as orientation and setting applicable to this study. Aim: The aim of the research was to identify and understand how follower experiences and expectations of leadership behaviours in a safety-critical commercial environment can affect leadership training and growth. The above-mentioned motivated this investigation of leadership traits and behaviours within an explicit context and from a follower’s viewpoint. Setting: The setting for the study was twenty two Air Traffic and Navigation Services Company sites where followers’ experiences and expectations of leadership behaviours in an air navigation service provider (ANSP organisation were investigated and served as orientation and setting applicable to this study. Methods: An ethnographic case study research style was adopted and followed because it allowed for an all-inclusive, holistic narrative report and interpretation. The samples for the quantitative and qualitative components of this study were parallel and methods employed addressed different aspects of the phenomenon, which allowed for a mixed methods research design. A one-way causality in the research design was observed because traits of followers that might influence leaders’ behaviours were excluded. Data were collected by means of a Leader Trait and Behaviour Questionnaire completed by participants
Safety Requirements and Modern Technical Requirements in Human Information Systems in Amman Hotels
Farouq Ahmad Alazzam; Sattam Rakan Allahawiah; Mohammad Nayef Alsarayreh; Kafa Hmoud Abdallah al Nawaiseh
2015-01-01
This study aimed to demonstrate the availability of Safety requirements and modern technical requirements in human information systems in Amman hotels. an the most important results of this study is the availability of security and safety requirements in human information systems In Amman hotels and The adequacy of the information that it provided .and show that all departments are not connected by appropriate and effective communication networks in adequate form . Also sophisticated operatin...
International Nuclear Information System (INIS)
Losey, D. C.; Miles, R. E.; Perks, M. F.
2009-01-01
The Criticality Safety Evaluation Report (CSER) for the Hanford Tank Waste Treatment and Immobilization Plant (WTP) has been developed as a single, integrated evaluation with a scope that covers all of the planned WTP operations. This integrated approach is atypical, as the scopes of criticality evaluations are usually more narrowly defined. Several adjustments were made in developing the WTP CSER, but the primary changes were to provide introductory overview for the criticality safety control strategy and to provide in-depth analysis of the underlying physical and chemical mechanisms that contribute to ensuring safety. The integrated approach for the CSER allowed a more consistent evaluation of safety and avoided redundancies that occur when evaluation is distributed over multiple documents. While the approach used with the WTP CSER necessitated more coordination and teamwork, it has yielded a report is that more integrated and concise than is typical. The integrated approach with the CSER produced a simple criticality control scheme that uses relatively few controls. (authors)
International Nuclear Information System (INIS)
Kim, Man Cheol; Jang, Seung Cheol; Ha, Jae Joo
2007-01-01
It is generally known that software reliability growth models such as the Jelinski-Moranda model and the Goel-Okumoto's Non-Homogeneous Poisson Process (NHPP) model cannot be applied to safety-critical software due to a lack of software failure data. In this paper, by applying two of the most widely known software reliability growth models to sample software failure data, we demonstrate the possibility of using the software reliability growth models to prove the high reliability of safety-critical software. The high sensitivity of a piece of software's reliability to software failure data, as well as a lack of sufficient software failure data, is also identified as a possible limitation when applying the software reliability growth models to safety-critical software
Burn-up credit in criticality safety of PWR spent fuel
Energy Technology Data Exchange (ETDEWEB)
Mahmoud, Rowayda F., E-mail: Rowayda_mahmoud@yahoo.com [Metallurgy Department, Nuclear Research Center, Atomic Energy Authority (Egypt); Shaat, Mohamed K. [Nuclear Engineering, Reactors Department, Nuclear Research Center, Atomic Energy Authority (Egypt); Nagy, M.E.; Agamy, S.A. [Professor of Nuclear Engineering, Nuclear and Radiation Department, Alexandria University (Egypt); Abdelrahman, Adel A. [Metallurgy Department, Nuclear Research Center, Atomic Energy Authority (Egypt)
2014-12-15
Highlights: • Designing spent fuel wet storage using WIMS-5D and MCNP-5 code. • Studying fresh and burned fuel with/out absorber like “B{sub 4}C and Ag–In–Cd” in racks. • Sub-criticality was confirmed for fresh and burned fuel under specific cases. • Studies for BU credit recommend increasing fuel burn-up to 60.0 GWD/MTU. • Those studies require new core structure materials, fuel composition and cladding. - Abstract: The criticality safety calculations were performed for a proposed design of a wet spent fuel storage pool. This pool will be used for the storage of spent fuel discharged from a typical pressurized water reactor (PWR). The mathematical model based on the international validated codes, WIMS-5 and MCNP-5 were used for calculating the effective multiplication factor, k{sub eff}, for the spent fuel stored in the pool. The data library for the multi-group neutron microscopic cross-sections was used for the cell calculations. The k{sub eff} was calculated for several changes in water density, water level, assembly pitch and burn-up with different initial fuel enrichment and new types and amounts of fixed absorbers. Also, k{sub eff} was calculated for the conservative fresh fuel case. The results of the calculations confirmed that the effective multiplication factor for the spent fuel storage is sub-critical for all normal and abnormal states. The future strategy for the burn-up credit recommends increasing the fuel burn-up to a value >60.0 GWD/MTU, which requires new fuel composition and new fuel cladding material with the assessment of the effects of negative reactivity build up.
International Nuclear Information System (INIS)
WHITE, W.F.
1999-01-01
This document specifies the critical characteristics for Commercial Grade Items (CGI) procured for PFP's criticality alarm system as required by HNF-PRO-268 and HNF-PRO-1819. These are the minimum specifications that the equipment must meet in order to properly perform its safety function. There may be several manufacturers or models that meet the critical characteristics for any one item. PFP's Criticality Alarm System includes the nine criticality alarm system panels and their associated hardware. This includes all parts up to the first breaker in the electrical distribution system. Specific system boundaries and justifications are contained in HNF-SD-CP-SDD-003, ''Definition and Means of Maintaining the Criticality Detectors and Alarms Portion of the PFP Safety Envelope.'' The procurement requirements associated with the system necessitates procurement of some system equipment as Commercial Grade Items in accordance with HNF-PRO-268, ''Control of Purchased Items and Services.''
From Safety Critical Java Programs to Timed Process Models
DEFF Research Database (Denmark)
Thomsen, Bent; Luckow, Kasper Søe; Thomsen, Lone Leth
2015-01-01
frameworks, we have in recent years pursued an agenda of translating hard-real-time embedded safety critical programs written in the Safety Critical Java Profile [33] into networks of timed automata [4] and subjecting those to automated analysis using the UPPAAL model checker [10]. Several tools have been...... built and the tools have been used to analyse a number of systems for properties such as worst case execution time, schedulability and energy optimization [12–14,19,34,36,38]. In this paper we will elaborate on the theoretical underpinning of the translation from Java programs to timed automata models...... and briefly summarize some of the results based on this translation. Furthermore, we discuss future work, especially relations to the work in [16,24] as Java recently has adopted first class higher order functions in the form of lambda abstractions....
Long-term criticality safety concerns associated with surplus fissile material disposition
International Nuclear Information System (INIS)
Choi, J.S.
1995-01-01
A substantial inventory of surplus fissile material would result from ongoing and planned dismantlement of US and Russian nuclear weapons. This surplus fissile material could be dispositioned by irradiation in nuclear reactors, and the resulting spent MOx fuel would be similar in radiation characteristics to regular LWR spent UO2 fuel. The surplus fissile material could also be immobilized into high-level waste forms, such as borosilicate glass, synroc, or metal-alloy matrix. The MOx spent fuel, or the immobilized waste forms, could then be directly disposed of in a geologic repository. Long-term criticality safety concerns arise because the fissile contents (i.e., Pu-239 and its decay daughter U-235) in these waste forms are higher than in LWR spent UO2 fuel. MOx spent fuel could contain 3 to 4 wt% of reactor-grade plutonium, compared to only 0.9 wt% of plutonium in LWR spent UO2 fuel. At some future time (tens of thousand of years), when the waste forms had deteriorated due to intruding groundwater, the water could mix with the long-lived fissile materials to form into a critical system. If the critical system is self-sustaining, somewhat like the natural-occurring reactor in OKLO, fission products produced could readily be available for dissolution and release out to the accessible environment, adversely affecting public health and safety. This paper will address ongoing activities to evaluate long-term criticality safety concerns associated with disposition of fissile material in a geologic setting. Issues to be addressed include the identification of a worst-case water-intrusion scenario and waste-form geometries which present the most concern for long-term criticality safety; and suggests of technical solutions for such concerns
Waste Encapsulation and Storage Facility interim operational safety requirements
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.
Licensing process for safety-critical software-based systems
Energy Technology Data Exchange (ETDEWEB)
Haapanen, P. [VTT Automation, Espoo (Finland); Korhonen, J. [VTT Electronics, Espoo (Finland); Pulkkinen, U. [VTT Automation, Espoo (Finland)
2000-12-01
System vendors nowadays propose software-based technology even for the most critical safety functions in nuclear power plants. Due to the nature of software faults and the way they cause system failures new methods are needed for the safety and reliability evaluation of these systems. In the research project 'Programmable automation systems in nuclear power plants (OHA)', financed together by the Radiation and Nuclear Safety Authority (STUK), the Ministry of Trade and Industry (KTM) and the Technical Research Centre of Finland (VTT), various safety assessment methods and tools for software based systems are developed and evaluated. As a part of the OHA-work a reference model for the licensing process for software-based safety automation systems is defined. The licensing process is defined as the set of interrelated activities whose purpose is to produce and assess evidence concerning the safety and reliability of the system/application to be licensed and to make the decision about the granting the construction and operation permissions based on this evidence. The parties of the licensing process are the authority, the licensee (the utility company), system vendors and their subcontractors and possible external independent assessors. The responsibility about the production of the evidence in first place lies at the licensee who in most cases rests heavily on the vendor expertise. The evaluation and gauging of the evidence is carried out by the authority (possibly using external experts), who also can acquire additional evidence by using their own (independent) methods and tools. Central issue in the licensing process is to combine the quality evidence about the system development process with the information acquired through tests, analyses and operational experience. The purpose of the licensing process described in this report is to act as a reference model both for the authority and the licensee when planning the licensing of individual applications
Licensing process for safety-critical software-based systems
International Nuclear Information System (INIS)
Haapanen, P.; Korhonen, J.; Pulkkinen, U.
2000-12-01
System vendors nowadays propose software-based technology even for the most critical safety functions in nuclear power plants. Due to the nature of software faults and the way they cause system failures new methods are needed for the safety and reliability evaluation of these systems. In the research project 'Programmable automation systems in nuclear power plants (OHA)', financed together by the Radiation and Nuclear Safety Authority (STUK), the Ministry of Trade and Industry (KTM) and the Technical Research Centre of Finland (VTT), various safety assessment methods and tools for software based systems are developed and evaluated. As a part of the OHA-work a reference model for the licensing process for software-based safety automation systems is defined. The licensing process is defined as the set of interrelated activities whose purpose is to produce and assess evidence concerning the safety and reliability of the system/application to be licensed and to make the decision about the granting the construction and operation permissions based on this evidence. The parties of the licensing process are the authority, the licensee (the utility company), system vendors and their subcontractors and possible external independent assessors. The responsibility about the production of the evidence in first place lies at the licensee who in most cases rests heavily on the vendor expertise. The evaluation and gauging of the evidence is carried out by the authority (possibly using external experts), who also can acquire additional evidence by using their own (independent) methods and tools. Central issue in the licensing process is to combine the quality evidence about the system development process with the information acquired through tests, analyses and operational experience. The purpose of the licensing process described in this report is to act as a reference model both for the authority and the licensee when planning the licensing of individual applications. Many of the
International Nuclear Information System (INIS)
Povyakalo, A.A.
2000-01-01
The paper provides basic definitions and describes the basic procedure of the Formal Qualitative Safety Analysis (FQSA) of critical software algorithms. The procedure is described by C-based pseudo-code. It uses the notion of weakest precondition and representation of a given critical algorithm by a Gurevich's Abstract State Mashine (GASM). For a given GASM and a given Catastrophe Condition the procedure results in a Catastrophe Inevitability Condition (it means that every sequence of algorithm steps lead to a catastrophe early or late), Danger Condition (it means that next step may lead to a catastrophe or make a catastrophe to be inevitable, but a catastrophe may be prevented yet), Safety Condition (it means that a next step can not lead to a catastrophe or make a catastrophe to be inevitable). The using of proposed procedure is illustrated by a simplest test example of algorithm. The FQSA provides a logical basis for PSA of critical algorithm. (author)
Failure mode and effect analysis on safety critical components of space travel
Directory of Open Access Journals (Sweden)
Kouroush Jenab
2015-07-01
Full Text Available Sending men to space has never been an ordinary activity, it requires years of planning and preparation in order to have a chance of success. The payoffs of reliable and repeatable space flight are many, including both Commercial and Military opportunities. In order for reliable and repeatable space flight to become a reality, catastrophic failures need to be detected and mitigated before they occur. It can be shown that small pieces of a design which seem ordinary can create devastating impacts if not designed and tested properly. This paper will address the use of a Failure Mode, Effects, and Criticality Analysis (FMECA with modified Risk Priority Number (RPN and its application to safety critical design components of shuttle liftoff. An example will be presented here which specifically focuses on the Solid Rocket Boosters (SRBs to illustrate the FMECA approach to reliable space travel.
Bowen, Brent, Ed.
This document contains four papers concerning collegiate aviation research and education solutions to critical safety issues. "Panel Proposal Titled Collegiate Aviation Research and Education Solutions to Critical Safety Issues for the Tim Forte Collegiate Aviation Safety Symposium" (Brent Bowen) presents proposals for panels on the…
Fissile materials principles of criticality safety in handling and processing
International Nuclear Information System (INIS)
1976-01-01
This Swedish Standard consists of the English version of the International Standard ISO 1709-1975-Nuclear energy. Fissile materials. Principles of criticality safety in handling and processing. (author)
Critical/non-critical system methodology report
International Nuclear Information System (INIS)
1989-01-01
The method used to determine how the waste Isolation Pilot Plant (WIPP) facilities/systems were classified as critical or non-critical to the receipt of CH waste is described within this report. All WIPP critical facilities/systems are listed in the Operational Readiness Review Dictionary. Using the Final Safety Analysis Report (FSAR) as a guide to define the boundaries of the facilities/systems, a direct correlation of the ORR Dictionary to the FSAR can be obtained. The critical facilities/systems are those which are directly related to or have a critical support role in the receipt of CH waste. The facility/systems must meet one of the following requirements to be considered critical: (a) confinement or measure of the release of radioactive materials; (b) continued receipt and/or storage of transuranic waste (TRU) without an interruption greater than one month according to the shipping plan schedule; (c) the environmental and occupational safety of personnel meets the established site programs; and (d) the physical security of the WIPP facilities
FOOD QUALITY MANAGEMENT AND SAFETY
Rizwana Khatoon; Debkumar Chakraborty; R.C. Chandni; Amar Sankar; A.V. Raghu
2017-01-01
Food safety system mainly focuses on identifying and preventing hazards that may lead product to deteriorate. The main important of manufacturing practice is a system that ensures that products meet food safety, quality and legal requirements. The hazard analysis and critical control point system, applies to food safety management, uses the approach of controlling critical points in food handling to prevent food safety problems. Besides enhancing food safety, other benefits of applying HACCP ...
Effect of fissile isotope burnup on criticality safety for stored disintegrated fuel rods
International Nuclear Information System (INIS)
Heaberlin, S.W.; Selby, G.P.
1978-09-01
If the fuel rods were to disintegrate and water added, a criticality could occur in a 13-in. PWR canister with fresh fuel enriched to 3.5 wt % 235 U. The question is, ''If credit could be taken for burnup, could this indicate a subcritical condition.'' In attempting to answer this question, a series of calculations were performed. A set of isotopic concentrations were generated for 5,000, 10,000, 15,000, and 20,000 MWD/MTU burnup levels. Four reflector materials, water, concrete and two types of soil, were considered. Results indicate that allowing credit for fissile isotope burnup does not completely remove the concern for criticality safety in the event of rod disintegration. Reactivities which are ''subcritical'' (k/sub eff/ = 0.95) would not occur for three of the four reflector materials at even the 20,000 MWD/MTU burnup level in the 13-in. canister. The water reflected canister would achieve the k/sub eff/ = 0.95 level near 18,000 MWD/MTU. A smaller canister could be postulated. If a quarter inch gap is allowed, a Westinghouse 17 x 17 PWR assembly requires a 12 1 / 4 inch diameter canister. For such a canister with water reflection the ''subcritical'' (k/sub eff/ = 0.95) level would be reached near 15,000 MWD/MTU. The soil reflected canisters would reach this level between 18,000 and 19,000 MWD/MTU. Considering the difficulties in taking credit for burnup, such modest gains in apparent safety are not encouraging. This situation might be improved, however, if credit were also taken for neutron absorption by fission product poisons produced during burnup. It is strongly recommended that other approaches to a solution of the criticality safety problem be considered
International Nuclear Information System (INIS)
Sheaffer, M.K.; Keeton, S.C.
1993-01-01
This report evaluates nuclear criticality safety for Spray Booth Operations in the Decontamination and Recovery Facility, X-705, at the Portsmouth Gaseous Diffusion Plant. A general description of current procedures and related hardware/equipment is presented. Control parameters relevant to nuclear criticality safety are explained, and a consolidated listing of administrative controls and safety systems is developed. Based on compliance with DOE Orders and MMES practices, the overall operation is evaluated, and recommendations for enhanced safety are suggested
Software Reliability Issues Concerning Large and Safety Critical Software Systems
Kamel, Khaled; Brown, Barbara
1996-01-01
This research was undertaken to provide NASA with a survey of state-of-the-art techniques using in industrial and academia to provide safe, reliable, and maintainable software to drive large systems. Such systems must match the complexity and strict safety requirements of NASA's shuttle system. In particular, the Launch Processing System (LPS) is being considered for replacement. The LPS is responsible for monitoring and commanding the shuttle during test, repair, and launch phases. NASA built this system in the 1970's using mostly hardware techniques to provide for increased reliability, but it did so often using custom-built equipment, which has not been able to keep up with current technologies. This report surveys the major techniques used in industry and academia to ensure reliability in large and critical computer systems.
Criticality safety of low-density storage arrays
International Nuclear Information System (INIS)
Bauer, T. H.; Nuclear Engineering Division
2005-01-01
This paper proposes a straightforward bounding method for the criticality safety analysis of fissionable materials configured into large arrays of standard containers. While criticality-safe storage limits have been well established for single containers, even under flooded conditions, it is also necessary to rule out any potential for criticality arising from neutronic interactions among multiple containers that might build up over long distances in a large array. Traditionally, the array problem has been approached by individual Monte Carlo analyses of explicit arrangements of single units and their surroundings. Deemphasizing specific configurations, the present technique takes advantage of low average density of fissionable material in typical storage arrays to separate neutron interactions that take place in the neutron's 'birth unit' from subsequent interactions in a dilute array. Numerous explicit Monte Carlo analyses show that array effects may be conservatively calculated by analyses that homogenize fissionable contents and depend only on the overall array shape, size, and reflective boundary
Criticality safety of low-density storage arrays
International Nuclear Information System (INIS)
Bauer, T.H.
1996-01-01
This paper proposes a straightforward bounding method for the criticality safety analysis of fissionable materials configured into large arrays of standard containers. While criticality-safe storage limits have been well established for single containers, even under flooded conditions, it is also necessary to rule out any potential for criticality arising from neutronic interactions among multiple containers that might build up over long distances in a large array. Traditionally, the array problem has been approached by individual Monte Carlo analyses of explicit arrangements of single units and their surroundings. Deemphasizing specific configurations, the present technique takes advantage of low average density of fissionable material in typical storage arrays to separate neutron interactions that take place in the neutron's open-quotes birth unitclose quotes from subsequent interactions in a dilute array. Numerous explicit Monte Carlo analyses show that array effects may be conservatively calculated by analyses that homogenize fissionable contents and depend only on the overall array shape, size, and reflective boundary
REVEAL - A tool for rule driven analysis of safety critical software
International Nuclear Information System (INIS)
Miedl, H.; Kersken, M.
1998-01-01
As the determination of ultrahigh reliability figures for safety critical software is hardly possible, national and international guidelines and standards give mainly requirements for the qualitative evaluation of software. An analysis whether all these requirements are fulfilled is time and effort consuming and prone to errors, if performed manually by analysts, and should instead be dedicated to tools as far as possible. There are many ''general-purpose'' software analysis tools, both static and dynamic, which help analyzing the source code. However, they are not designed to assess the adherence to specific requirements of guidelines and standards in the nuclear field. Against the background of the development of I and C systems in the nuclear field which are based on digital techniques and implemented in high level language, it is essential that the assessor or licenser has a tool with which he can automatically and uniformly qualify as many aspects as possible of the high level language software. For this purpose the software analysis tool REVEAL has been developed at ISTec and the Halden Reactor Project. (author)
Critical safety issues in the design of fusion machines
International Nuclear Information System (INIS)
Kramer, W.
1991-01-01
In the course of developing fusion machines both general safety considerations and safety assessments for the various components and systems of actual machines increase in number and become more and more coherent. This is particularly true for the NET/ITER projects where safety analysis plays an increasing role for the design of the machine. Since in a D/T tokamak the radiological hazards will be dominant basic radiological safety objectives are discussed. Critical safety issues as identified in particular by the NET/ITER community are reviewed. Subsequently, issues of major concern are considered both for normal operation and for conceivable accidents. The following accidents are considered to be crucial: Loss of cooling in plasma facing components, loss of vacuum, tritium system failure, and magnet system failure. To mitigate accident consequences a confinement concept based on passive features and multiple barriers including detritiation and filtering has to be applied. The reactor building as final barrier needs special attention to cope with both internal and external hazards. (orig.)
Directory of Open Access Journals (Sweden)
Sergio Saponara
2016-03-01
Full Text Available This paper presents an actuator control unit (ACU with a 450-J embedded energy storage backup to face safety critical mechatronic applications. The idea is to ensure full operation of electric actuators, even in the case of battery failure, by using supercapacitors as a local energy tank. Thanks to integrated switching converter circuitry, the supercapacitors provide the required voltage and current levels for the required time to guarantee actuator operation until the system enters into safety mode. Experimental results are presented for a target application related to the control of servomotors for a robotized prosthetic arm. Mechatronic devices for rehabilitation or assisted living of injured and/or elderly people are available today. In most cases, they are battery powered with lithium-based cells, providing high energy density and low weight, but at the expense of a reduced robustness compared to lead-acid- or nickel-based battery cells. The ACU of this work ensures full operation of the wearable robotized arm, controlled through acceleration and electromyography (EMG sensor signals, even in the case of battery failure, thanks to the embedded energy backup unit. To prove the configurability and scalability of the proposed solution, experimental results related to the electric actuation of the car door latch and of a robotized gearbox in vehicles are also shown. The reliability of the energy backup device has been assessed in a wide temperature range, from −40 to 130 °C, and in a durability test campaign of more than 10,000 cycles. Achieved results prove the suitability of the proposed approach for ACUs requiring a burst of power of hundreds of watts for only a few seconds in safety-critical applications. Alternatively, the aging and temperature characterizations of energy backup units is limited to supercapacitors of thousands of farads for high power applications (e.g., electric/hybrid propulsion and with a temperature range limited to
Donovan, Sarah-Louise; Salmon, Paul M; Horberry, Timothy; Lenné, Michael G
2018-01-01
Safety leadership is an important factor in supporting safe performance in the workplace. The present case study examined the role of safety leadership during the Bingham Canyon Mine high-wall failure, a significant mining incident in which no fatalities or injuries were incurred. The Critical Decision Method (CDM) was used in conjunction with a self-reporting approach to examine safety leadership in terms of decisions, behaviours and actions that contributed to the incidents' safe outcome. Mapping the analysis onto Rasmussen's Risk Management Framework (Rasmussen, 1997), the findings demonstrate clear links between safety leadership decisions, and emergent behaviours and actions across the work system. Communication and engagement based decisions featured most prominently, and were linked to different leadership practices across the work system. Further, a core sub-set of CDM decision elements were linked to the open flow and exchange of information across the work system, which was critical to supporting the safe outcome. The findings provide practical implications for the development of safety leadership capability to support safety within the mining industry. Copyright © 2017 Elsevier Ltd. All rights reserved.
OSHA safety requirements for hazardous chemicals in the workplace.
Dohms, J
1992-01-01
This article outlines the Occupational Safety and Health Administration (OSHA) requirements set forth by the Hazard Communication Standard, which has been in effect for the healthcare industry since 1987. Administrators who have not taken concrete steps to address employee health and safety issues relating to hazardous chemicals are encouraged to do so to avoid the potential of large fines for cited violations. While some states administer their own occupational safety and health programs, they must adopt standards and enforce requirements that are at least as effective as federal requirements.
Cluster monte carlo method for nuclear criticality safety calculation
International Nuclear Information System (INIS)
Pei Lucheng
1984-01-01
One of the most important applications of the Monte Carlo method is the calculation of the nuclear criticality safety. The fair source game problem was presented at almost the same time as the Monte Carlo method was applied to calculating the nuclear criticality safety. The source iteration cost may be reduced as much as possible or no need for any source iteration. This kind of problems all belongs to the fair source game prolems, among which, the optimal source game is without any source iteration. Although the single neutron Monte Carlo method solved the problem without the source iteration, there is still quite an apparent shortcoming in it, that is, it solves the problem without the source iteration only in the asymptotic sense. In this work, a new Monte Carlo method called the cluster Monte Carlo method is given to solve the problem further
The Canadian Nuclear Safety Commission's financial guarantee requirements
International Nuclear Information System (INIS)
Ferch, R.
2006-01-01
The Nuclear Safety and Control Act gives the Canadian Nuclear Safety Commission (CNSC) the legal authority to require licensees to provide financial guarantees in order to meet the purposes of the Act. CNSC policy and guidance with regard to financial guarantees is outlined, and the current status of financial guarantee requirements as applied to various CNSC licensees is described. (author)
Impact of axial burnup profile on criticality safety of ANPP spent fuel cask
International Nuclear Information System (INIS)
Bznuni, S.
2006-01-01
Criticality safety assessment for WWER-440 NUHOMS cask with spent nuclear fuel from Armenian NPP has been performed. The cask was designed in such way that the neutron multiplication factor k eff must be below 0,95 for all operational modes and accident conditions. Usually for criticality analysis, fresh fuel approach with the highest enrichment is taken as conservative assumption as it was done for ANPP. NRSC ANRA in order to improve future fuel storage efficiency initiated research with taking into account burn up credit in the criticality safety assessment. Axial burn up profile (end effect) has essential impact on criticality safety justification analysis. However this phenomenon was not taken into account in the Safety Analysis Report of NUHOMS spent fuel storage constructed on the site of ANPP. Although ANRA does not yet accept burn up credit approach for ANPP spent fuel storage, assessment of impact of axial burnup profile on criticality of spent fuel assemblies has important value for future activities of ANRA. This paper presents results of criticality calculations of spent fuel assemblies with axial burn up profile. Horizontal burn up profile isn't taken account since influence of the horizontal variation of the burn up is much less than the axial variation. The actinides and actinides + fission products approach are discussed. The calculations were carried out with STARBUCS module of SCALE 5.0 code package developed at Oak Ridge National laboratory. SCALE5.0 sequence CSAS26 (KENO-VI) was used for evaluation the k eff for 3-D problems. Obtained results showed that criticality of ANPP spent fuel cask is very sensitive to the end effect
International Nuclear Information System (INIS)
Kataoka, Isao; Sekimoto, Hiroshi
2000-01-01
The Research Committee of Nuclear Safety carried out a research on criticality accident at the JCO plant according to statement of president of the Japan Atomic Energy Society on October 8, 1999, of which results are planned to be summarized by the constitutions shown as follows, for a report on the 'Questionnaires of criticality accident in the Uranium Fuel Processing Plant of the JCO, Inc.': general criticality safety, fuel cycle and the JCO, Inc.; elucidation on progress and fact of accident; cause analysis and problem picking-up; proposals on improvement; and duty of the Society. Among them, on last two items, because of a conclusion to be required for members of the Society at discussions of the Committee, some questionnaires were send to more than 1800 of them on April 5, 2000 with name of chairman of the Committee. As results of the questionnaires contained proposals and opinions on a great numbers of fields, some key-words like words were found on a shape of repeating in most questionnaires. As they were thought to be very important nuclei in these two items, they were further largely classified to use for summarizing proposals and opinions on the questionnaires. This questionnaire had a big characteristic on the duty of the Society in comparison with those in the other organizations. (G.K.)
Safety considerations of new critical assembly for the Research Reactor Institute, Kyoto University
International Nuclear Information System (INIS)
Umeda, Iwao; Matsuoka, Naomi; Harada, Yoshihiko; Miyamoto, Keiji; Kanazawa, Takashi
1975-01-01
The new critical assembly type of nuclear reactor having three cores for the first time in the world was completed successfully at the Research Reactor Institute of Kyoto University in autumn of 1974. It is called KUCA (Kyoto University Critical Assembly). Safety of the critical assembly was considered sufficiently in consequence of discussions between the researchers of the institute and the design group of our company, and then many bright ideas were created through the discussions. This paper is described the new safety design of main equipments - oil pressure type center core drive mechanism, removable water overflow mechanism, core division mechanism, control rod drive mechansim, protection instrumentation system and interlock key system - for the critical assembly. (author)
Energy Technology Data Exchange (ETDEWEB)
NONE
2012-04-15
This publication is a revision of Safety Requirements No. NS-R-1, Safety of Nuclear Power Plants: Design. It establishes requirements applicable to the design of nuclear power plants and elaborates on the safety objective, safety principles and concepts that provide the basis for deriving the safety requirements that must be met for the design of a nuclear power plant. It will be useful for organizations involved in the design, manufacture, construction, modification, maintenance, operation and decommissioning of nuclear power plants, as well as for regulatory bodies. Contents: 1. Introduction; 2. Applying the safety principles and concepts; 3. Management of safety in design; 4. Principal technical requirements; 5. General plant design; 6. Design of specific plant systems.
International Nuclear Information System (INIS)
1991-12-01
As part of ongoing US Nuclear Regulatory Commission (NRC) efforts to ensure the quality and accountability of safety issue information, a program was established whereby an annual NUREG report would be published on the status of licensee implementation and NRC verification of safety issues in major NRC requirements areas. This information was compiled and reported in three NUREG volumes. Volume 1, published in March 1991, addressed the status of of Three Mile Island (TMI) Action Plan Requirements. Volume 2, published in May 1991, addressed the status of unresolved safety issues (USIs). Volume 3, published in June 1991, addressed the implementation and verification status of generic safety issues (GSIs). This annual NUREG report combines these volumes into a single report and provides updated information as of September 30, 1991. The data contained in these NUREG reports are a product of the NRC's Safety Issues Management System (SIMS) database, which is maintained by the Project Management Staff in the Office of Nuclear Reactor Regulation and by NRC regional personnel. This report is to provide a comprehensive description of the implementation and verification status of TMI Action Plan Requirements, safety issues designated as USIs, and GSIs that have been resolved and involve implementation of an action or actions by licensees. This report makes the information available to other interested parties, including the public. An additional purpose of this NUREG report is to serve as a follow-on to NUREG-0933, ''A Prioritization of Generic Safety Issues,'' which tracks safety issues up until requirements are approved for imposition at licensed plants or until the NRC issues a request for action by licensees
High-Speed Maglev Trains; German Safety Requirements
1991-12-31
This document is a translation of technology-specific safety requirements developed : for the German Transrapid Maglev technology. These requirements were developed by a : working group composed of representatives of German Federal Railways (DB), Tes...
GROWTH OF THE INTERNATIONAL CRITICALITY SAFETY AND REACTOR PHYSICS EXPERIMENT EVALUATION PROJECTS
Energy Technology Data Exchange (ETDEWEB)
J. Blair Briggs; John D. Bess; Jim Gulliford
2011-09-01
Since the International Conference on Nuclear Criticality Safety (ICNC) 2007, the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP) have continued to expand their efforts and broaden their scope. Eighteen countries participated on the ICSBEP in 2007. Now, there are 20, with recent contributions from Sweden and Argentina. The IRPhEP has also expanded from eight contributing countries in 2007 to 16 in 2011. Since ICNC 2007, the contents of the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments1' have increased from 442 evaluations (38000 pages), containing benchmark specifications for 3955 critical or subcritical configurations to 516 evaluations (nearly 55000 pages), containing benchmark specifications for 4405 critical or subcritical configurations in the 2010 Edition of the ICSBEP Handbook. The contents of the Handbook have also increased from 21 to 24 criticality-alarm-placement/shielding configurations with multiple dose points for each, and from 20 to 200 configurations categorized as fundamental physics measurements relevant to criticality safety applications. Approximately 25 new evaluations and 150 additional configurations are expected to be added to the 2011 edition of the Handbook. Since ICNC 2007, the contents of the 'International Handbook of Evaluated Reactor Physics Benchmark Experiments2' have increased from 16 different experimental series that were performed at 12 different reactor facilities to 53 experimental series that were performed at 30 different reactor facilities in the 2011 edition of the Handbook. Considerable effort has also been made to improve the functionality of the searchable database, DICE (Database for the International Criticality Benchmark Evaluation Project) and verify the accuracy of the data contained therein. DICE will be discussed in separate papers at ICNC 2011. The status of the
Metrics design for safety assessment
Luo, Yaping; van den Brand, M.G.J.
2016-01-01
Context:In the safety domain, safety assessment is used to show that safety-critical systems meet the required safety objectives. This process is also referred to as safety assurance and certification. During this procedure, safety standards are used as development guidelines to keep the risk at an
Energy Technology Data Exchange (ETDEWEB)
Mattson, Roger J.
1989-09-01
This is a report on the 1989 independent Criticality Safety Assessment of the Rocky Flats Plant, primarily in response to public concerns that nuclear criticality accidents involving plutonium may have occurred at this nuclear weapon component fabrication and processing plant. The report evaluates environmental issues, fissile material storage practices, ventilation system problem areas, and criticality safety practices. While no evidence of a criticality accident was found, several recommendations are made for criticality safety improvements. 9 tabs.
Neutron nuclear data measurements for criticality safety
Directory of Open Access Journals (Sweden)
Guber Klaus
2017-01-01
Full Text Available To support the US Department of Energy Nuclear Criticality Safety Program, neutron-induced cross section experiments were performed at the Geel Electron Linear Accelerator of the Joint Research Center Site Geel, European Union. Neutron capture and transmission measurements were carried out using metallic natural cerium and vanadium samples. Together with existing data, the measured data will be used for a new evaluation and will be submitted with covariances to the ENDF/B nuclear data library.
NCIS: a nuclear criticality information system
International Nuclear Information System (INIS)
Koponen, B.L.; Hampel, V.E.
1984-01-01
The NCIS is one of the developments carried out to meet the requirements in the field of criticality safety information. Its primary goal is to enhance nuclear criticality safety by dissemination of data, standards, and training material. This paper presents the ''NCIS'' progess since 1950: computer-searching, database management, nuclear critical experiments bibliography. American Nuclear Society transactions criticality safety publications compilation, edition of a personnel directory representing over 140 organizations located in 16 countries and showing a wide range of specialists involved in the field of nuclear criticality safety. The NCIS uses the information management and communication resources of TIS (Technology Information System): automated access procedures; creation of program-dependent information systems; communications. The NCIS is still in a growing, formative stage; it has concentrated first on collecting and organizing the nuclear criticality literature; nuclear critical data, calculational tools, standards, and training materials will follow. Finally the planned and contemplated resources are dealt with: expansion of bibliographic compilations; news database; fundamental criticality safety reference; criticality benchmarck database; user community; training resources; related resources; criticality accident database; dynamic databook; dynamic textbook; expert knowledge system; and, extraction of intelligence
Cyclic executive for safety-critical Java on chip-multiprocessors
DEFF Research Database (Denmark)
Ravn, Anders P.; Schoeberl, Martin
2010-01-01
, that uses model checking to find a static schedule, if one exists at all, which gives an implementation of a table driven multiprocessor scheduler. To evaluate the proposed cyclic executive for multiprocessors we have implemented it in the context of safety-critical Java on a Java processor....
International Nuclear Information System (INIS)
Lee, Seung Jun; Jung, Wondea Jung
2015-01-01
Some researchers recognized Bayesian belief network (BBN) method to be a promising method of quantifying software reliability. Brookhaven National Laboratory (BNL) comprehensively reviewed various quantitative software reliability methods to identify the most promising methods for use in probabilistic safety assessments (PSAs) of digital systems of NPPs against a set of the most desirable characteristics developed therein. BBNs are recognized as a promising way of quantifying software reliability and are useful for integrating many aspects of software engineering and quality assurance. The method explicitly incorporates important factors relevant to reliability, such as the quality of the developer, the development process, problem complexity, testing effort, and the operation environment. In this work, a BBN model was developed to estimate the number of remained defects in a safety-critical software based on the quality evaluation of software development life cycle (SDLC). Even though a number of software reliability evaluation methods exist, none of them can be applicable to the safety-critical software in an NPP because software quality in terms of PDF is required for the PSA
Criticality safety of solvent extraction process
International Nuclear Information System (INIS)
Tachimori, Shoichi; Miyoshi, Yoshinori
1987-01-01
The article presents some comments on criticality safety of solvent extraction processes. When used as an extracting medium, tributyl phosphate extracts nitric acid and water, in addition to nitrates of U and Pu, into the organic phase. The amount of these chemical species extracted into the organic phase is dependent on and restricted by the concentrations of tributyl phosphate and other components. For criticality control, measures are taken to decrease the concentration of tributyl phosphate in the organic phase, in addition to control of the U and Pu concentrations in the feed water phase. It should be remembered that complexes of tributyl phosphate with nitrates of such metals as Pu(IV), Pu(VI), U(IV) and Th(IV) do not dissolve uniformly in the organic phase. In criticality calculation for solution-handling systems, U and Pu are generally assumed to have a valence of 6 and 4, respectively. In the reprocessing extraction process, however, U and Pu can have a valence of 4, and 3 and 6, respectively. The organic phase and aqueous phase contact in a counter-current flow. U and Pu will be accumulated if they are not brought out of the extraction system by this flow. (Nogami, K.)
Vectorization of the KENO V.a criticality safety code
International Nuclear Information System (INIS)
Hollenbach, D.F.; Dodds, H.L.; Petrie, L.M.
1991-01-01
The development of the vector processor, which is used in the current generation of supercomputers and is beginning to be used in workstations, provides the potential for dramatic speed-up for codes that are able to process data as vectors. Unfortunately, the stochastic nature of Monte Carlo codes prevents the old scalar version of these codes from taking advantage of the vector processors. New Monte Carlo algorithms that process all the histories undergoing the same event as a batch are required. Recently, new vectorized Monte Carlo codes have been developed that show significant speed-ups when compared to the scalar version of themselves or equivalent codes. This paper discusses the vectorization of an already existing and widely used criticality safety code, KENO V.a All the changes made to KENO V.a are transparent to the user making it possible to upgrade from the standard scalar version of KENO V.a to the vectorized version without learning a new code
Discussion on several important safety requirements for the new nuclear power plant
International Nuclear Information System (INIS)
Yan Tianwen; Li Jigen; Zhang Lin; Feng Youcai; Jia Xiang; Li Wenhong
2013-01-01
Post the Fukushima nuclear accident, the Chinese government raised higher safety goals and safety requirements for the new nuclear power plant to be constructed. The paper expounded the important indicators of safety requirements and the aspects of safety modification that had been developed for the new NPPs. It also discussed and analyzed the main fields required by the new NPPs safety requirements in the safety goals, safety evaluation of sites, defenses of internal and external events, severe accident prevention and mitigation, design of reactor core, containment system and I and C system, and optimization of engineering measure, which gave some references to the design, construction and safety modifications of new NPPs in China. (authors)
Basuni, Enas M; Bayoumi, Magda M
2015-01-13
Intensive care units (ICUs) provide lifesaving care for the critically ill patients and are associated with significant risks. Moreover complexity of care within ICUs requires that the health care professionals exhibit a trans-disciplinary level of competency to improve patient safety. This study aimed at using staff development strategies through implementing patient safety educational program that may minimize the medical errors and improve patient outcome in hospital. The study was carried out using a quasi experimental design. The settings included the intensive care units at General Mohail Hospital and National Mohail Hospital, King Khalid University, Saudi Arabia. The study was conducted from March to June 2012. A convenience sample of all prevalent nurses at three shifts in the aforementioned settings during the study period was recruited. The program was implemented on 50 staff nurses in different ICUs. Their age ranged between 25-40 years. Statistically significant relation was revealed between safety climate and job satisfaction among nurses in the study sample (p=0.001). The years of experiences in ICU ranged between one year 11 (16.4) to 10 years 20 (29.8), most of them (68%) were working in variable shift, while 32% were day shift only. Improvements were observed in safety climate, teamwork climate, and nurse turnover rates on ICUs after implementing a safety program. On the heels of this improvement; nurses' total knowledge, skills and attitude were enhanced regarding patient safety dimensions. Continuous educational program for ICUs nursing staff through organized in-service training is needed to increase their knowledge and skills about the importance of improving patient safety measure. Emphasizing on effective collaborative system also will improve patient safety measures in ICUS.
International Nuclear Information System (INIS)
Busche, D.M.
1995-09-01
During Fiscal Year 1992, the US Department of Energy, Richland Operations Office (RL) separately transmitted the following US Department of Energy (DOE) Orders to Westinghouse Hanford Company (WHC) for compliance: DOE 5480.21, ''Unreviewed Safety Questions,'' DOE 5480.22, ''Technical Safety Requirements,'' and DOE 5480.23, ''Nuclear Safety Analysis Reports.'' WHC has proceeded with its impact assessment and implementation process for the Orders. The Orders are closely-related and contain some requirements that are either identical, similar, or logically-related. Consequently, WHC has developed a strategy calling for an integrated implementation of the three Orders. The strategy is comprised of three primary objectives, namely: Obtain DOE approval of a single list of DOE-owned and WHC-managed Nuclear Facilities, Establish and/or upgrade the ''Safety Basis'' for each Nuclear Facility, and Establish a functional Unreviewed Safety Question (USQ) process to govern the management and preservation of the Safety Basis for each Nuclear Facility. WHC has developed policy-revision and facility-specific implementation plans to accomplish near-term tasks associated with the above strategic objectives. This plan, which as originally submitted in August 1993 and approved, provided an interpretation of the new DOE Nuclear Facility definition and an initial list of WHC-managed Nuclear Facilities. For each current existing Nuclear Facility, existing Safety Basis documents are identified and the plan/status is provided for the ISB. Plans for upgrading SARs and developing TSRs will be provided after issuance of the corresponding Rules
Critical safety parameters: The logical approach to refresher training
International Nuclear Information System (INIS)
Johnson, A.R.; Pilkington, W.; Turner, S.
1991-01-01
Nuclear power plant managers must ensure that control room staff are able to perform effectively. This is of particular importance through the longer term after initial authorization. Traditionally refresher training has been based on delivery of fragmented training packages typically derived from the initial authorization training programs. Various approaches have been taken to provide a more integrated refresher training program. However, methods such as job and task analysis and subject matter expert derived training have tended to develop without a focused clear overall training objective. The primary objective of all control room staff training is to ensure a proper and safe response to all plant transients. At the Point Lepreau Nuclear Plant, this has defined the Critical Safety Parameter based refresher training program. The overall objective of the Critical Safety Parameter training program is to ensure that control room staff can monitor and control a discrete set of plant parameters. Maintenance of the selected parameters within defined boundaries assures adequate cooling of the fuel and containment of radioactivity. Control room staff need to be able to reliably respond correctly to plant transients under potentially high stress conditions,. utilizing the essential knowledge and skills to deal with such transients. The inference is that the knowledge and skills must be limited to that which can be reliably recalled. This paper describes how the Point Lepreau Nuclear Plant has developed a refresher training program on the basis of a limited number of Critical Safety Parameters. Through this approach, it has been possible to define the essential set of knowledge and skills which ensures a correct response to plant transients
Design requirements of communication architecture of SMART safety system
International Nuclear Information System (INIS)
Park, H. Y.; Kim, D. H.; Sin, Y. C.; Lee, J. Y.
2001-01-01
To develop the communication network architecture of safety system of SMART, the evaluation elements for reliability and performance factors are extracted from commercial networks and classified the required-level by importance. A predictable determinacy, status and fixed based architecture, separation and isolation from other systems, high reliability, verification and validation are introduced as the essential requirements of safety system communication network. Based on the suggested requirements, optical cable, star topology, synchronous transmission, point-to-point physical link, connection-oriented logical link, MAC (medium access control) with fixed allocation are selected as the design elements. The proposed architecture will be applied as basic communication network architecture of SMART safety system
The official website of the U.S. department of energy's nuclear criticality safety program
Energy Technology Data Exchange (ETDEWEB)
Koponen, B.; Heinrichs, D.; Lee, C. [Lawrence Livermore National Laboratory, CA (United States); Scott, L. [SAIC, Solana Beach, CA (United States)
2014-07-01
The U.S. Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP) mission is to provide sustainable expert leadership, direction, and the technical infrastructure necessary to develop, maintain, and disseminate the essential technical tools, training, and data to support safe, efficient fissionable material operations within the DOE. The NCSP Website site makes a variety of information available to the criticality safety practitioner, including reference materials, training modules and links to related sites. It assists criticality safety personnel to keep abreast of NCSP activities or current developments in criticality safety via a 'What's New' section within the Website. Convenient access to the many useful features of the Website is available via drop-down menus. The Website is also available to non-DOE and international professionals tasked with ensuring safe operations involving fissionable nuclear materials. (author)
International Nuclear Information System (INIS)
Broadhead, B.L.; Hopper, C.M.; Childs, R.L.; Parks, C.V.
1999-01-01
This report presents the application of sensitivity and uncertainty (S/U) analysis methodologies to the code/data validation tasks of a criticality safety computational study. Sensitivity and uncertainty analysis methods were first developed for application to fast reactor studies in the 1970s. This work has revitalized and updated the available S/U computational capabilities such that they can be used as prototypic modules of the SCALE code system, which contains criticality analysis tools currently used by criticality safety practitioners. After complete development, simplified tools are expected to be released for general use. The S/U methods that are presented in this volume are designed to provide a formal means of establishing the range (or area) of applicability for criticality safety data validation studies. The development of parameters that are analogous to the standard trending parameters forms the key to the technique. These parameters are the D parameters, which represent the differences by group of sensitivity profiles, and the ck parameters, which are the correlation coefficients for the calculational uncertainties between systems; each set of parameters gives information relative to the similarity between pairs of selected systems, e.g., a critical experiment and a specific real-world system (the application)
TWRS safety SSCs: Requirements and characteristics
International Nuclear Information System (INIS)
Smith-Fewell, M.A.
1997-01-01
Safety Systems, Structures, and Components (SSCs) have been identified from hazard and accident analyses. These analyses were performed to support the Tank Waste Remediation System (TWRS) Final Safety Analysis Report (FSAR) and Basis for Interim Operation (BID). The text identifies and evaluates the SSCs and their supporting SSCs to show that they either prevent the occurrence of the accident or mitigate the consequences of the accident to below the acceptance guidelines. The requirements for the SSCs to fulfill these tasks are described
Evaluation for nuclear safety-critical software reliability of DCS
International Nuclear Information System (INIS)
Liu Ying
2015-01-01
With the development of control and information technology at NPPs, software reliability is important because software failure is usually considered as one form of common cause failures in Digital I and C Systems (DCS). The reliability analysis of DCS, particularly qualitative and quantitative evaluation on the nuclear safety-critical software reliability belongs to a great challenge. To solve this problem, not only comprehensive evaluation model and stage evaluation models are built in this paper, but also prediction and sensibility analysis are given to the models. It can make besement for evaluating the reliability and safety of DCS. (author)
A new approach to the criticality safety assessment of PCM at BNFL Sellafield
International Nuclear Information System (INIS)
Darby, Sam; Kirkwood, Dave
2003-01-01
Plutonium Contaminated Material (PCM) arises as a solid waste on the Sellafield Site and is packaged into 200 litre drums which are placed into interim surface storage arrays. These wastes may also contain 235 U. The traditional approach to criticality safety has been based on ''worst-case'' reactivity modelling. This has recently led to a number of difficulties by implying that the 230 g (Pu + 235 U) drum limit is very important for criticality safety and the assay instruments used to demonstrate compliance with the limit need a high level of safety reliability. Also, the reliability and accuracy of the assay results of historical or legacy PCM became an issue. The new focus on substantiation of safety related equipment in BNFL has highlighted reliability shortfalls for the assay instruments. To overcome these shortfalls, additional operational practices on the PCM handling regimes were introduced to give increased confidence in the fissile assay results. These practices significantly delayed processing PCM waste stocks and resulted in significant additional operator dose uptake. Thus there were strong reasons to improve the existing approach. This paper describes a new approach to the criticality modelling of PCM. (author)
Understanding the application of knowledge management to the safety critical facilities
International Nuclear Information System (INIS)
Ilina, Elena
2010-01-01
Challenges to the operating nuclear power plants and transport infrastructures are outlined. It is concluded that most aggravating factors are related to knowledge. Thus, of necessity, effective knowledge management is required. Knowledge management theories are reviewed in their historical perspective as a natural extension and unification of information theories and theories about learning. The first line is identified with names as Wiener, Ashby, Shannon, Jaynes, Dretske, Harkevich. The second line - with Vygotsky, Engestroem, Carayannis. The recent developments of knowledge management theorists as Davenport, Prusak, Drew, Wiig, Zack are considered stressing learning, retaining of knowledge, approaching the state awareness of awareness, and alignment of knowledge management with the strategy of the concerned organizations. Further, some of the details and results are presented of what is achieved so far. More specifically, knowledge management tools are applied to the practical work activities as event reporting, data collection, condition assessment, verification of safety functions and incident investigation. Obstacles are identified and improvements are proposed. Finally, it is advised to continue to implement and further develop knowledge management tools in the organizations involved in various aspects of safety critical facilities
NASA's Software Safety Standard
Ramsay, Christopher M.
2007-01-01
NASA relies more and more on software to control, monitor, and verify its safety critical systems, facilities and operations. Since the 1960's there has hardly been a spacecraft launched that does not have a computer on board that will provide command and control services. There have been recent incidents where software has played a role in high-profile mission failures and hazardous incidents. For example, the Mars Orbiter, Mars Polar Lander, the DART (Demonstration of Autonomous Rendezvous Technology), and MER (Mars Exploration Rover) Spirit anomalies were all caused or contributed to by software. The Mission Control Centers for the Shuttle, ISS, and unmanned programs are highly dependant on software for data displays, analysis, and mission planning. Despite this growing dependence on software control and monitoring, there has been little to no consistent application of software safety practices and methodology to NASA's projects with safety critical software. Meanwhile, academia and private industry have been stepping forward with procedures and standards for safety critical systems and software, for example Dr. Nancy Leveson's book Safeware: System Safety and Computers. The NASA Software Safety Standard, originally published in 1997, was widely ignored due to its complexity and poor organization. It also focused on concepts rather than definite procedural requirements organized around a software project lifecycle. Led by NASA Headquarters Office of Safety and Mission Assurance, the NASA Software Safety Standard has recently undergone a significant update. This new standard provides the procedures and guidelines for evaluating a project for safety criticality and then lays out the minimum project lifecycle requirements to assure the software is created, operated, and maintained in the safest possible manner. This update of the standard clearly delineates the minimum set of software safety requirements for a project without detailing the implementation for those
Nutritional requirements of the critically ill patient.
Chan, Daniel L
2004-02-01
The presence or development of malnutrition during critical illness has been unequivocally associated with increased morbidity and mortality in people. Recognition that malnutrition may similarly affect veterinary patients emphasizes the need to properly address the nutritional requirements of hospitalized dogs and cats. Because of a lack in veterinary studies evaluating the nutritional requirements of critically ill small animals, current recommendations for nutritional support of veterinary patients are based largely on sound clinical judgment and the best information available, including data from experimental animal models and human studies. This, however, should not discourage the veterinary practitioner from implementing nutritional support in critically ill patients. Similar to many supportive measures of critically ill patients, nutritional interventions can have a significant impact on patient morbidity and may even improve survival. The first step of nutritional support is to identify patients most likely to benefit from nutritional intervention. Careful assessment of the patient and appraisal of its nutritional needs provide the basis for a nutritional plan, which includes choosing the optimal route of nutritional support, determining the number of calories to provide, and determining the composition of the diet. Ultimately, the success of the nutritional management of critically ill dogs and cats will depend on close monitoring and frequent reassessment.
International Nuclear Information System (INIS)
Huget, R.G.; Viola, M.; Froebel, P.A.
1995-01-01
Ontario Hydro has had experience in designing and qualifying safety critical software used in the reactor shutdown systems of its nuclear generating stations. During software design, an analysis of system level hazards and potential hardware failure effects provide input to determining what safeguards will be needed. One form of safeguard, called software self checks, continually monitor the health of the computer on line. The design of self checks usually is a trade off between the amount of computing resources required, the software complexity, and the level of safeguarding provided. As part of the software verification activity, a software hazards analysis is performed, which identifiers any failure modes that could lead to the software causing an unsafe state, and which recommends changes to mitigate that potential. These recommendations may involve a re-structuring of the software to be more resistant to failure, or the introduction of other safeguarding measures. This paper discusses how Ontario Hydro has implemented these aspects of software design and verification into safety critical software used in reactor shutdown systems
Characteristics of safety critical organizations . work psychological perspective
International Nuclear Information System (INIS)
Oedewald, P.; Reiman, T.
2006-02-01
This book deals with organizations that operate in high hazard industries, such as the nuclear power, aviation, oil and chemical industry organisations. The society puts a great strain on these organisations to rigorously manage the risks inherent in the technology they use and the products they produce. In this book, an organisational psychology view is taken to analyse what are the typical challenges of daily work in these environments. The analysis is based on a literature review about human and organisational factors in safety critical industries, and on the interviews of Finnish safety experts and safety managers from four different companies. In addition to this, personnel interviews conducted in the Finnish nuclear power plants are utilised. The authors come up with eight themes that seem to be common organizational challenges cross the industries. These include e.g. how does the personnel understand the risks and what is the right level for rules and procedures to guide the work activities. The primary aim of this book is to contribute to the Finnish nuclear safety research and safety management discussion. However, the book is equally suitable for risk management, organizational development and human resources management specialists in different industries. The purpose is to encourage readers to consider how the human and organizational factors are seen in the field they work in. (orig.)
Training and qualification program for nuclear criticality safety technical staff
International Nuclear Information System (INIS)
Taylor, R.G.; Worley, C.A.
1996-01-01
A training and qualification program for nuclear criticality safety technical staff personnel has been developed and implemented. The program is compliant with requirements and provides evidence that a systematic approach has been taken to indoctrinate new technical staff. Development involved task analysis to determine activities where training was necessary and the standard which must be attained to qualify. Structured mentoring is used where experienced personnel interact with candidates using checksheets to guide candidates through various steps and to provide evidence that steps have been accomplished. Credit can be taken for the previous experience of personnel by means of evaluation boards which can credit or modify checksheet steps. Considering just the wealth of business practice and site specific information a new person at a facility needs to assimilate, the program has been effective in indoctrinating new technical staff personnel and integrating them into a productive role. The program includes continuing training
New Improved Nuclear Data for Nuclear Criticality and Safety
International Nuclear Information System (INIS)
Guber, Klaus H.; Leal, Luiz C.; Lampoudis, C.; Kopecky, S.; Schillebeeckx, P.; Emiliani, F.; Wynants, R.; Siegler, P.
2011-01-01
The Geel Electron Linear Accelerator (GELINA) was used to measure neutron total and capture cross sections of 182,183,184,186 W and 63,65 Cu in the energy range from 100 eV to ∼200 keV using the time-of-flight method. GELINA is the only high-power white neutron source with excellent timing resolution and ideally suited for these experiments. Concerns about the use of existing cross-section data in nuclear criticality calculations using Monte Carlo codes and benchmarks were a prime motivator for the new cross-section measurements. To support the Nuclear Criticality Safety Program, neutron cross-section measurements were initiated using GELINA at the EC-JRC-IRMM. Concerns about data deficiencies in some existing cross-section evaluations from libraries such as ENDF/B, JEFF, or JENDL for nuclear criticality calculations were the prime motivator for new cross-section measurements. Over the past years many troubles with existing nuclear data have emerged, such as problems related to proper normalization, neutron sensitivity backgrounds, poorly characterized samples, and use of improper pulse-height weighting functions. These deficiencies may occur in the resolved- and unresolved-resonance region and may lead to erroneous nuclear criticality calculations. An example is the use of the evaluated neutron cross-section data for tungsten in nuclear criticality safety calculations, which exhibit discrepancies in benchmark calculations and show the need for reliable covariance data. We measured the neutron total and capture cross sections of 182,183,184,186 W and 63,65 Cu in the neutron energy range from 100 eV to several hundred keV. This will help to improve the representation of the cross sections since most of the available evaluated data rely only on old measurements. Usually these measurements were done with poor experimental resolution or only over a very limited energy range, which is insufficient for the current application.
Technical safety requirements for the Annular Core Research Reactor Facility (ACRRF)
International Nuclear Information System (INIS)
Boldt, K.R.; Morris, F.M.; Talley, D.G.; McCrory, F.M.
1998-01-01
The Technical Safety Requirements (TSR) document is prepared and issued in compliance with DOE Order 5480.22, Technical Safety Requirements. The bases for the TSR are established in the ACRRF Safety Analysis Report issued in compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports. The TSR identifies the operational conditions, boundaries, and administrative controls for the safe operation of the facility
Criticality safety of spent fuel casks considering water inleakage
International Nuclear Information System (INIS)
Osgood, N.L.; Withee, C.J.; Easton, E.P.
2004-01-01
A fundamental safety design parameter for all fissile material packages is that a single package must be critically safe even if water leaks into the containment system. In addition, criticality safety must be assured for arrays of packages under normal conditions of transport (undamaged packages) and under hypothetical accident conditions (damaged packages). The U.S. Nuclear Regulatory Commission staff has revised the review protocol for demonstrating criticality safety for spent fuel casks. Previous review guidance specified that water inleakage be considered under accident conditions. This practice was based on the fact that the leak tightness of spent fuel casks is typically demonstrated by use of structural analysis and not by physical testing. In addition, since a single package was shown to be safe with water inleakage, it was concluded that this analysis was also applicable to an array of damaged packages, since the heavy shield walls in spent fuel casks neutronically isolate each cask in the array. Inherent in this conclusion is that the fuel assembly geometry does not change significantly, even under drop test conditions. Requests for shipping fuel with burnup exceeding 40 GWd/MTU, including very high burnups exceeding 60 GWD/MTU, caused a reassessment of this assumption. Fuel cladding structural strength and ductility were not clearly predictable for these higher burnups. Therefore the single package analysis for an undamaged package may not be applicable for the damaged package. NRC staff developed a new practice for review of spent fuel casks under accident conditions. The practice presents two methods for approval that would allow an assessment of potential reconfiguration of the fuel assembly under accident conditions, or, alternatively, a demonstration of the water-exclusion boundary through physical testing
Governmental, Legal and Regulatory Framework for Safety. General Safety Requirements. Part 1
Energy Technology Data Exchange (ETDEWEB)
NONE
2010-09-15
The objective of this publication is to establish requirements in respect of the governmental, legal and regulatory framework for safety. It covers the essential aspects of the framework for establishing a regulatory body and taking other actions necessary to ensure the effective regulatory control of facilities and activities utilized for peaceful purposes. Other responsibilities and functions, such as liaison within the global safety regime and on support services for safety (including radiation protection), emergency preparedness and response, nuclear security, and the State system of accounting for and control of nuclear material, are also covered.
International Nuclear Information System (INIS)
Wang, Tai-Ran; Mousseau, Vincent; Pedroni, Nicola; Zio, Enrico
2017-01-01
The technical problem addressed in the present paper is the assessment of the safety criticality of energy production systems. An empirical classification model is developed, based on the Majority Rule Sorting method, to evaluate the class of criticallity of the plant/system of interest, with respect to safety. The model is built on the basis of a (limited-size) set of data representing the characteristics of a number of plants and their corresponding criticality classes, as assigned by experts. The construction of the classification model may raise two issues. First, the classification examples provided by the experts may contain contradictions: a validation of the consistency of the considered dataset is, thus, required. Second, uncertainty affects the process: a quantitative assessment of the performance of the classification model is, thus, in order, in terms of accuracy and confidence in the class assignments. In this paper, two approaches are proposed to tackle the first issue: the inconsistencies in the data examples are “resolved” by deleting or relaxing, respectively, some constraints in the model construction process. Three methods are proposed to address the second issue: (i) a model retrieval-based approach, (ii) the Bootstrap method and (iii) the cross-validation technique. Numerical analyses are presented with reference to an artificial case study regarding the classification of Nuclear Power Plants. - Highlights: • We use a hierarchical framework to represent safety criticality. • We use an empirical classification model to evaluate safety criticality. • Inconsistencies in data examples are “resolved” by deleting/relaxing constraints. • Accuracy and confidence in the class assignments are computed by three methods. • Method is applied to fictitious Nuclear Power Plants.
Nuclear safety requirements for upgrading the National Repository for Radioactive Wastes-Baita Bihor
International Nuclear Information System (INIS)
Vladescu, Gabriela; Necula, Daniela
2000-01-01
The upgrading project of National Repository for Radioactive Wastes-Baita Bihor is based on the integrated concept of nuclear safety. Its ingredients are the following: A. The principles of nuclear safety regarding the management of radioactive wastes and radioprotection; B. Safety objectives for final disposal of low- and intermediate-level radioactive wastes; C. Safety criteria for final disposal of low- and intermediate-level radioactive wastes; D. Assessment of safety criteria fulfillment for final disposal of low- and intermediate-level radioactive wastes. Concerning the nuclear safety in radioactive waste management the following issues are considered: population health protection, preventing transfrontier contamination, future generation radiation protection, national legislation, control of radioactive waste production, interplay between radioactive waste production and management, radioactive waste repository safety. The safety criteria of final disposal of low- and intermediate-level radioactive wastes are discussed by taking into account the geological and hydrogeological configuration, the physico-chemical and geochemical characteristics, the tectonics and seismicity conditions, extreme climatic potential events at the mine location. Concerning the requirements upon the repository, the following aspects are analyzed: the impact on environment, the safety system reliability, the criticality control, the filling composition to prevent radioactive leakage, the repository final sealing, the surveillance. Concerning the radioactive waste, specific criteria taken into account are the radionuclide content, the chemical composition and stability, waste material endurance to heat and radiation. The waste packaging criteria discussed are the mechanical endurance, materials toughness and types as related to deterioration caused by handling, transportation, storing or accidents. Fulfillment of safety criteria is assessed by scenarios analyses and analyses of