Operation Of Nuclear Plants Research Articles

The development and use of large scale information systems for plant operating experience and component failure data

The design of pressure components for very high levels of structural reliability involves taking account of three types of variations or uncertainties. These include (1) the normal range of materials properties measured under laboratory conditions; (2) the normal or calculated ranges of load and duty cycles; (3) the added range of variation in properties due to fabrication, environment, and aging, and the possible added range of load or duty cycles due to infrequent transient conditions. Direct testing and analysis can reasonably attain confidence of failure rates of 10 −3/yr. The assurance of still lower rates - to 10 −6/yr, desirable for nuclear applications, benefits from a combination of testing and analysis, but augmented by intensive use of actual field experience of failures or degradation found by inspection. The scopes and uses of two major data systems are described. These are (1) the Significant Events Evaluation and Information Network (SEE-IN), and (2) the Nuclear Plant Reliability Data System (NPRDS). Together these systems cover the cumulative experience of ∼1,000 unit-years of nuclear plant operation. Uses of these systems to refine operations, maintenance, rework, and in some cases design or specifications, is described.

Environmental Reporting: Before and After TMI

Mass media coverage of environmental events and issues, including problems at nuclear power plants, is a complicated affair, full of controversy and constraints imposed by the complexity of the information to be covered and by journalistic traditions and media economic conditions. Smaller newspapers and broadcast stations have a particularly hard time because they do not often employ reporters that have enough educational background or experience in a given area to cover complex technical topics. The author covered the Three Mile Island accident and studied the media coverage of TMI before and during the accident to find out how much local residents have been told about the general nuclear plant operations and possible consequences of the accident. She discussed her findings in this paper.

Anticipating Control Failure and Operator Error in Nuclear Power Plant Safety

In the operation of commercial nuclear power plants, large guidebooks have been prepared, documenting proper procedures in the event of various hardware or control failures. Although recognized as having a major impact on overall system safety, human error has not received as much attention from the standpoint of anticipating specific errors and designing against them. Using system diagrams constructed from overall plan design diagrams, it was possible to define subsystem dependencies. It was then possible to construct 80 realistic operation and maintenance errors and control malfunctions, to analyze their symptoms and effects, and to construct sequences of actions to mitigate the situation or to prevent serious consequences. Preventative as well as corrective measures were developed. Methods employed in this study appear to have general application in system safety.

The Safe Operation of Nuclear Plants: Implementing Federal Policy in the Aftermath of Three Mile Island

The safe operation of nuclear power plants represents an important class of problems in the implementation of regulatory policy. These problems are characterized by a low tolerance for terror, high organizational and technical complexity, and highly visible, costly outcomes. The key to designing policies that address these problems is not to predict and regulate every possible source of error, but to design incentives such that organizations create their own error-detecting and solving systems. The current policy toward nuclear plant safety stresses technical and regulatory solutions at the expense of financial incentives that would induce utilities and plant personnel to engage in safe operation.

The Use of Historical Data Storage and Retrieval Systems at Nuclear Power Plants

In order to assist the nuclear plant operator in the assessment of useful historical plant information, C-E has developed the Historical Data Storage and Retrieval (HDSR) system, which will record, store, recall, and display historical information as it is needed by plant personnel. The system has been designed to respond to the user's needs under a variety of situations. The user is offered the choice of viewing historical data on color video displays as groups or on computer printouts as logs. The graphical representation is based upon a sectoring concept that provides a zoom-in enlargement of sections of the HDSR graphs.

Human reliability in nuclear plant operation and maintenance : Goldman, A., and Koch, W.K. In: Proceedings of the 1981 Annual Reliability and Maintainability Symposium, Jan 1981, pp 180–184

Human reliability is a central concept in assuring the safety and productivity of man-machine systems; but application to nuclear plant operation and maintenance management have been neglected. Correcting that oversight is possible and would be immediately effective. The relationship between state-of-the-art in human factors technology and maintenance is explained and the role of management in monitoring human reliability is made explicit. 9 refs.

Submarine Propulsion in the Royal Navy

The paper outlines the history of submarine propulsion from the early days, through the hydrogen peroxide plants on Explorer and Excalibur to the setting up of the nuclear submarine programme. The building of the submarine prototype at Dounreay, the purchase of the Dreadnought plant from the US and the design and construction of the Valiant class submarines formed the base for developments in the 1960s leading to the highly successful Resolution and Swiftsure class submarines. Lessons learned from the design, building and operation of nuclear submarine propulsion plants are discussed and the future requirements for unproved operational characteristics and for higher nuclear safety standards are examined against the constraints of keeping unit costs under control. The success of the nuclear submarine programme is shown by the position today where the Royal Navy has sixteen nuclear submarines in service, a new submarine class under construction and work on the next generation of nuclear propulsion plants well advanced.

The application of fracture mechanics in thermally stressed structures

There is considerable interest in calculating stress intensity factors at crack tips in thermally stressed structures, particularly in the power generation industry where the safe operation of both conventional and nuclear plant is founded on rigorous safety cases. Analytical methods to study such problems are of limited scope, although they can be extended by introducing numerical techniques. Purpose built numerical methods, however, offer a much greater and more accurate solution capability and in particular the finite element method is well advanced. Such methods are described, including how stress intensity factors can be obtained from the finite element results. They are then applied to a range of thermally stressed problems including plates with central cracks and cylinders with axial and circumferential cracks. Both steady state and transient temperature distributions arising from typical thermal shocks are considered.

Nuclear personnel training after TMI-2: The GPUN response

GPUN has made a significant commitment to improved training of all personnel involved in nuclear plant operations and support. This is demonstrated by the large increases in the numbers and quality of training personnel, improvements in training facilities, commitment to purchase basic principles trainers and replica simulators, implementation of a six-shift rotation with a 5-day training week, revision and upgrading of operator training and requalification programs and the significant expansion of training for all categories of GPU Nuclear personnel.

Criteria for safety related nuclear plant operator actions: A preliminary assessment of available data

The need for a quantitative data base on the reliability of nuclear power plant operators has long been recognised by human factors and reliability analysts, and the great need for further assessment of operator performance under accident conditions has been dramatically emphasised by the incident at Three Mile Island-2. In the US, an effort has been under way for a number of years to develop a design standard to define when required manual operator action can be accepted as part of a nuclear plant design basis. Insufficient data are available to provide quantitative guidelines for the standard. To provide the necessary data base to support such standards and the necessary quantitative assessment of operator reliability, the US Nuclear Regulatory Commission is sponsoring a study at Oak Ridge National Laboratory to develop the data base. A preliminary assessment, completed in April 1979, concluded that sufficient data from US operating experience did not exist to provide an adequate data base. A programme of research using full-scope nuclear plant simulators and results that are correlated to field data was suggested. That programme was recently initiated. This paper reviews the approach, results and conclusions of the preliminary assessment and summarises the planned research programme of simulator studies.

Fracture mechanics in design and service: ‘living with defects’ - Fracture mechanics as an aid to design and operation of nuclear plant

Fracture mechanics analyses are an important part of nuclear plant design, supplementing the conventional design protection against failure to cover the possibility of the presence of crack-like defects. The degree of detail and accuracy required for a particular application depends on the possible consequences of a failure and whether the assessment is concerned with plant safety or with aspects of reliability. In the former case, a conservative approach is necessary and the prevention of initiation is the usual criterion. This approach is typified by the safety assessment applied to pressurized water reactor pressure vessels, which is outlined and discussed in relation to elastic plastic approaches and the importance of plant transient conditions, material properties (especially in weldments) and possible defect distributions. Fracture mechanics can help in defining quality control and quality assurance procedures, including both requirements for mechanical property appraisal and nondestructive testing. The latter aspects extend into operation, in respect of monitoring of plant conditions, surveillance of changes in material properties and the use of periodic inspection and plant condition monitoring techniques. A number of examples are quoted and recommendations made to permit improved fracture mechanics assessments.

A Design to Enhance Detection of Preselected Events for Risk Reduction

This paper discusses the need to develop additional aids for nuclear plant operators during accident situations. The role of the operator, his working environment, the attitudes of licensing authorities, and the accident situation itself are discussed. The point is made that the mental flexibility of the operator, which is essential during an unanticipated accident sequence, must be in top condition during a high stress incident - exactly the type of incident which will promote the mental rigidity. Increased operator training alone is judged to be insufficient unless supplemented by other approaches to the problem. A system proposed by General Atomic to improve the situation is discussed - its principles are given and a test of the system, based upon the Three Mile Island accident, is described.

Maintenance and Testing Errors in Nuclear Power Plants: A Preliminary Assessment

Safety and reliability in the operation of nuclear power plants have been topics for intense analysis and debate in recent years. Once crucial factor which has received little attention until very recently, is human reliability in the operation, maintenance and testing of nuclear plants. Maintenance and testing errors are of particular importance in that, despite the fact that they are relatively few in number compared with hardware related events, their occurrence programs the system for future operator errors bv introducing erroneous data in operator-hardware system communication or by eliminating a portion of that communication. Erroneous data or a lack of anticipated feedback following control actions by the operator can tend to cause further inappropriate responses and to escalate the frequency of operator errors. Such effects are most undesirable during emergencies. A number of improvements based upon improved human factors engineering will be necessary to eliminate maintenance errors of the type encountered in this study. These include: standardization of design for given types of subsystems, standardization of maintenance operations, work simplification involving both physical and psychological aspects of maintenance work, the use of training simulators to increase the amount of practice in performing maintenance operations, automanual control to show predicted outcome of results, assignment of individual responsibility and accountability to specific hardware subsystems, measures of job performance against some criterion, programmed instruction, improved divisions of responsibility among maintenance, operating and technical personnel, and improved management practices.

Training System of PWR Type Nuclear Plant Operators

Training System of PWR Type Nuclear Plant Operators

Meeting ofIAEA Experts on85Kr Formed During Operation of Nuclear Plants

Meeting ofIAEA Experts on85Kr Formed During Operation of Nuclear Plants

A Strategy for a Non-Nuclear Future

The need for nuclear power may not be as great as the electric power industry has led the nation to believe, according to the authors. They argue that 64 of the 72 nuclear plants operating in the United States could be shut down immediately if the existing non-nuclear capacity of the electric power industry were fully utilized; and the remaining 8 plants could be phased out within a few years. They cite already-available alternative power sources that could guarantee the additional energy needed for a non-nuclear future. They state that the transition to a nuclear-free electric system could be implemented with little or no increased expense to consumers or taxpayers; that, in fact, elimination of all nuclear plants might actually be cheaper, given the rapid rise in nuclear construction costs as more and more new flaws are discovered or old ones acknowledged. The authors feel that environmental risks of nuclear power plant operation could be eliminated in exchange for a small, temporary increase in air pollution from coal- and oil-fired plants. The increase in sulfur dioxide and particulate pollution could be offset within several years by an accelerated program to install flue-gas scrubbing equipment. Suggestions for meeting a projected shortfallmore » in future capacity are given. The authors also touch lightly on institutional barriers that would have to be overcome before phasing out nuclear power. 4 figures, 4 tables.« less

The Effects of Learning by Doing on Nuclear Plant Operating Reliability

The Effects of Learning by Doing on Nuclear Plant Operating Reliability

Price-Anderson act declared unconstitutional: The decision and its effects on nuclear power

In March 1977, the $560 million limit on liability in the Price-Anderson Act was declared unconstitutional. The Price-Anderson Act sets forth a combination private-public insurance and compensation system for handling risks associated with commercial nuclear operations. The limit was found to violate the due process and equal protection provisions of the Fifth Amendment of the U.S. Constitution. This paper examines the salient points of the decision which include: (a) the effects of nuclear plant operations on the plaintiffs; (b) the dependence of nuclear power development on the Price-Anderson Act; (c) the plaintiff's right to bring suit; and (d) the rationale for declaring the Act unconstitutional. The potential effects include the possibility that many utilities and suppliers of nuclear plant components will terminate their nuclear business, the availability of capital funds for nuclear plants will be reduced, and that cost of capital will be increased to reflect the greater risk of nuclear development.

Design of a small single-purpose nuclear desalination plant compatible with the local resources in the middle east

Present plans in the Middle East involve the construction of several nuclear power plants with desalination capabilities to provide power and water to meet the requirements of the anticipated growth in the industrial sector and development of new settlements to improve the socio-economical aspects of population distribution. This effort has been matched by a program initiated by the Development Consultants Association (DCA) to provide the necessary training, manpower and expertise necessary for adequate involvement in siting, design, construction and operation of both nuclear and desalination plants. In this paper results of the preliminary stages of the design of a 2.6 million gallons per day (1000 cubic meters/day) single-purpose 40 MW thermal MSF-heavy water nuclear plant are reported. Design objectives and philosophy are reviewed. A descriprion is given of the neutronic, thermal, control and mechanical design parameters of the plant. The design is based on utilization of available local material, technology and manpower. The feasibility of production of heavy water in the fertilizer production plants and the extraction of natural uranium from the phospahate mines on the Red Sea coast are considered pointing out further stages of development and future plans.

Practical limitations of criteria for limiting radiation risks to the public

This paper is a sequel to an earlier contribution to this journal which reviewed the formal basis of the radiological protection criteria and dose limits employed in the control of radiation risks to members of the public. It outlines the methods employed to relate basic dose limits recommended by the I.C.R.P. and the M.R.C. to measureable environmental parameters through Derived Working Limits (DWLs) and Emergency Reference Levels (ERLs). The simplifying assumptions underlying these concepts and the practical limitations which they impose upon the use of DWLs and ERLs in the control of radiation exposure are described. Examples drawn from a range of operational and accidental releases of radioactivity from nuclear power reactors are used to illustrate areas in which improvements in design and operating criteria are needed in the future. In this paper it is shown that although derived parameters, such as DWLs and ERLs, will continue to be relevant in cases where a single radionuclide irradiates predominantly a single human body organ via a well defined pathway, the simplifications involved in their derivation impose limitations upon their usefulness in many practical situations. This will become increasingly true within an expanding nuclear power industry, where a wide range of radionuclides are generated and may be released to the environment either through routine operational discharges or accidentally under fault conditions. As the number and types of nuclear installations grow, it will become increasingly difficult to identify unambiguously a single critical route to man, either due to variations in the isotopic mixture originating from a given source or due to the introduction of additional sources which contribute to the exposure of a given individual. In addition, while the use of DWLs and ERLs enables the operator to demonstrate compliance with the basic dose limits, these parameters in themselves do not provide a numerate measure of the associated risks to members of the public. Dose estimation techniques, based on improved environmental and metabolic models, are however becoming available which enable a comprehensive description to be given of the dose distribution within an individual or group for any exposure regime of interest. The implications of these new techniques in the design and operation of nuclear plant are discussed and, in the case of accidental discharge limits, a modification of the current ERL dose limits used within the U.K. is suggested to take account of the relative risks associated with single organ and whole body exposure.