https://hdl.handle.net/1721.1/67475 Sun, 05 Apr 2026 06:42:07 GMT 2026-04-05T06:42:07Z https://hdl.handle.net/1721.1/75134 A System Dynamics Model of the Energy Policymaking Process Oggianu, Stella Maris; Hansen, Kent F. Electric energy is a fundamental commodity for any aspects of the modern world. However, there are many uncertainties in the sources of electricity that are going to be used in the future. Some of these uncertainties are inherent to the electricity technologies and to the costs of fuels, but the biggest uncertainties come from the impact of future regulations and policies on capital costs, and operations and maintenance costs. Although system dynamics models have been extensively used for applications to the electric power, all the existing models are based on the supply/demand dynamics, and policies are considered as externalities. On the contrary, the energy policymaking model (the EPM model) presented in this report focuses on the complementary problem. This is, the determination of how byproducts and issues related to the adequate supply of electric energy modify the opinions and perceptions of the diverse sectors of the social/political environment; the analysis of the aspects of this environment that account for the formation of energy policies, and the assessment of how these policies are determinants of the technology used to supply electricity. The technologies considered are nuclear, fossil and windmills. The architecture of the EPM model is based on the assumption that policies are formed to minimize societal concerns regarding energy availability and price, nuclear waste, nuclear proliferation, nuclear safety, fossil emissions including greenhouse effect, acid rain, and land requirements for windmills. In this way, each technology is measured by its ability to reduce these concerns. The resulting policies impact on the economics of each of these options. At the same time, economics determines the selection of the new source of electricity. One of the most important results derived from the simulations done through the EPM model is that the revival of the nuclear industry may not be enough to prevent the increase in the production of greenhouse gases. The limited capacity of the industry to build plants is an important factor to consider. Another result is that the opening of Yucca Mountain at the earliest date means the removal of an important barrier for the future growth of the industry, as the risk premium of nuclear power plants may be reduced. Also derived from the use of the EPM model is that the electricity market should not be completely deregulated due to the likely be shortage of electricity supply, and high concerns regarding electricity availability, during peak demands. Thu, 01 Aug 2002 00:00:00 GMT https://hdl.handle.net/1721.1/75134 2002-08-01T00:00:00Z https://hdl.handle.net/1721.1/75128 CATILaC: Computer-Aided Technique for Identifying Latent Conditions User's Manual, Version 1.2 Marchinkowski, K.; Weil, R.; Apostolakis, George E. 1. Overview 1.1 Introduction to the CATILaC Methodology By understanding the way that a facility coordinates the work it does, failure events can be placed into a broader organizational context. Once the organizational context is understood, steps can be taken to reduce the possibility of common-cause organizational failures. When this type of analysis is done in the context of a traditional Root Cause Analysis program, substantial insight into the possible causes of operational incidents can be obtained. This software package is designed to guide the user through the process of placing failure events into their organizational context. In doing so, the causes of the events and the human and hardware failures or deficiencies that lead to them will be better understood. Better corrective actions can be developed for all levels of the organization. The methodology involves both understanding what happened during the course of the event and identifying the hardware failures that contributed to its occurrence. To do this the analyst must identify the sequence of failures that occurred and the causes for each, locate the initiating, or trigger, event, and find the latent failures that became active during the event. Once the event is understood, the human contributions to each of the hardware factors must be identified and analyzed. During the analysis, deficient tasks within work processes are identified. By doing this, the latent conditions that led to the event can be discovered. Figure 1 shows how human contributions are linked to fallible decisions/organizational factors. CATILaC is focused on hardware failures and the human contributions that cause them rather than on operator actions that contribute to the event. Operations at a nuclear plant, especially post-trigger recovery actions, do not lend themselves to this type of work process analysis. Although it can be done using this software (see discussion of how to include operator contributions in Appendix I), there are other, more complete methods available to do that type of analysis. Sat, 01 Apr 2000 00:00:00 GMT https://hdl.handle.net/1721.1/75128 2000-04-01T00:00:00Z https://hdl.handle.net/1721.1/75127 Analysis and Utilization of Operating Experience for Organizational Learning Weil, R.; Apostolakis, George E. The objective of this report is to clarify the ways that organizational factors influence nuclear power plant performance in order to improve performance. Therefore, this report studied the nuclear power plant organizational environment by identifying and detailing its important work processes. These work processes are: the Work Request Work Process; the Condition Reporting Work Process; the External Operating Experience Work Process; the Design Change Process; and the Procedure Change Work Process. Using this information, a methodology of incident investigation that targets organizational deficiencies contributing to events was developed. Using this methodology to analyze recent significant incidents, a list of important organizational factors and the context within which they influence the successful completion of tasks was identified. These factors are: 1) Communication - Pervasive – Most important between different units and departments; 2) Formalization -Execution; 3) Goal Prioritization - Prioritization; 4) Problem Identification - Planning, scheduling, and return to normal line-up; 5) Roles and Responsibilities - Execution; and 6) Technical Knowledge (job specific knowledge and broad based knowledge) - Job specific knowledge – execution/ Broad based knowledge –prioritization, planning, scheduling, and other tasks. Although safety culture and organizational learning are not listed, they are important. The reason for their exclusion is that they are not single organizational factors useful when cited in incident investigations. Rather, safety culture is a term used to describe all organizational factors, including organizational structure, that impact performance. Similarly, organizational learning was excluded because it is a collection of programs, processes, individual attitudes and culture responsible for learning. Although organizational learning was not listed, it was studied resulting in the development of the Utilization of Operating Experience Work Process. The Utilization of Operating Experience Work Process consists of the following seven steps: 1) Identification; 2) Screening/Prioritization/Dissemination; 3) Investigation/Evaluation; 4) Development; ii i 5) Implementation; 6) Closeout; and 7) Verification/Validation. Since prioritization was identified as important in the above work process and the analysis of significant events, a methodology for the prioritization of work activities at nuclear power plants was developed. This methodology produces a prioritization tool that assigns a numerical performance index to each item requiring prioritization. Applying the methodology at Seabrook Station produced a tool that allowed those who prioritize external operating experience to more efficiently and accurately do so. In addition to the success of the application at Seabrook, a workshop was held at MIT with experts in prioritizing external operating experience. These experts further validated the methodology and the resulting tool. The final piece of work in this report is an analysis of the NRC's revised oversight process as it relates to safety culture. The performance-based regulatory approach is appropriate for regulating safety culture. However, the NRC should continue the analysis of operating experience to identify additional organizational factors and the context within which they influence performance. Furthermore, they should develop performance indicators and measurement instruments for each organizational factor so that plants would be better able to take responsibility to proactively manage their safety culture. Fri, 01 Jun 2001 00:00:00 GMT https://hdl.handle.net/1721.1/75127 2001-06-01T00:00:00Z https://hdl.handle.net/1721.1/75021 A Unified Risk-Informed Framework to Assess the Proliferation Risk and License the Proliferation Performace of Nuclear Energy d'Oro, Edoardo Cavalieri; Golay, Michael J. In order to strengthen the current non-proliferation regime it is necessary to guarantee high standards of security for the sites that use, store, produce, or reprocess special nuclear materials (SNM). The current surge of interest in nuclear energy requires resolution of concerns about the appropriateness of the current nuclear non-proliferation regulatory framework for the threats challenging nuclear energy systems (NES). This is especially true also considering that the structure of the current industry is exposed to imminent significant changes such as the introduction of small modular reactors (SMR), and the adoption of nuclear power in countries with unstable political systems. Over recent decades, countries nominally adhering to the Non-Proliferation Treaty (NPT) violated it by building concealed facilities, by manipulating the configuration of their power plants, and by diverting material from their nuclear energy research and production sites. These events show evidence of a major paradigm shift in the area of non-proliferation, which started with the rivalry between two major opponents (each being guardian of its arsenal and technologies during the cold-war), and later reconfigured itself into the confrontation between countries hosting nuclear technologies, or networks of opponents, trying to acquire materials, knowledge and skills necessary to build a nuclear weapon. To create an appropriate response to all the above issues, and thus to strengthen back the non-proliferation regime, while confronting the shifted paradigm of nuclear proliferation, new tools and methods for evaluating the proliferation risk associated with nuclear energy systems become necessary. In this thesis, I discuss some of the fundamental traits and assumptions of the framework I developed in order to assess the proliferation risks associated with NESs. Important decisions within the proliferation domain, can be evaluated by a systematic and holistic approach. The high-level objective of the framework proposed here is to create a license process for the proliferation performance of NESs, and to provide a platform to assist the evaluations of the different alternatives than can be taken in order to strengthen the current non-proliferation regime. Thu, 01 Sep 2011 00:00:00 GMT https://hdl.handle.net/1721.1/75021 2011-09-01T00:00:00Z https://hdl.handle.net/1721.1/75020 Application of the Technology Neutral Framework to Sodium-­Cooled Fast Reactors Johnson, Brian C.; Apostolakis, George E. Sodium cooled fast reactors (SFRs) are considered as a novel example to exercise the Technology Neutral Framework (TNF) proposed in NUREG-1860. One reason for considering SFRs is that they have historically had a licensing problem due to postulated core disruptive accidents. Two SFR designs are considered, and both meet the goals of the TNF that LWRs typically would not. Considering these goals have been met, a method for improving economics is proposed where systems of low risk-importance are identified as candidates for removal, simplification, or removal from safety grade. Seismic risk dominates these designs and is found to be a limiting factor when applying the TNF. Thu, 01 Sep 2011 00:00:00 GMT https://hdl.handle.net/1721.1/75020 2011-09-01T00:00:00Z https://hdl.handle.net/1721.1/75019 Stress Corrosion Cracking and Crack Tip Characterization of Alloy X-750 in Light Water Reactor Environments Gibbs, Jonathan Paul; Ballinger, Ronald; Ballinger, Ronald Stress corrosion cracking (SCC) susceptibility of Inconel Alloy X-750 in the HTH condition has been evaluated in high purity water at 93 and 288°C under Boiling Water Reactor Normal Water Chemistry (NWC) and Hydrogen Water Chemistry (HWC) conditions. SCC crack growth rates of approximately 1.1x10-7 mm/s (K=28 MPa√m) under NWC conditions and 1.4x10-8 mm/s (K=28 MPa√m) under HWC in high purity water at 288°C were observed. The environmental conditions were changed from NWC to HWC during constant K loading, and the crack growth rate immediately slowed down by approximately one order of magnitude. The alloy was also tested in HWC at 93°C. No SCC crack growth was observed at K= 35 MPa√m for the length of time tested at 93°C. The fracture mode transitioned from predominantly transgranular cracking under fatigue conditions to a mixture of intergranular, pseudo-intergranular, and a small amount of transgranular fracture in constant stress intensity SCC. Pseudo-intergranular cracking is when a crack propagates directly adjacent to the grain boundary carbides and not actually on the grain boundary. The SCC crack tips were characterized with scanning electron microscopy (SEM) and 3D Atom Probe Tomography (APT). The SEM analysis was focused on the fractographic analysis and crackpropagation mode. The crack was observed to propagate adjacent to grain boundary carbides (pseudo-intergranular) and along a boundary with high coherency where no carbides were present (intergranular). The small and localized areas of transgranular cracking were occasionally seen between two regions of intergranular cracking. The APT reconstructions of the crack tips and crack wall identified several key features contributing to the SCC process: 1) Preferential oxygen transport occurs in either a finger-like or crystallographic morphology extending from the crack tip region. These regions are enriched in both oxygen and oxide with the oxide being a chromium-nickel spinel. 2) The matrix ahead of each finger-like “tunnel” is enriched in oxygen and predominantly chromium oxide. This indicates that oxygen is diffusing ahead of the crack tip into the bulk material. 3) The oxygen that penetrates directly into the base material from the crack walls in an ordered manner suggests that it is controlled by crystallographic features. 4) The main SCC crack tip is full of predominantly oxide phase and, to a lesser extent, metal atoms. The very crack tip forms a spinel of chromium and nickel oxides. Iron oxide begins to contribute to the oxide spinel approximately 25-30 nm from the actual tip. 5) The γ’ precipitates that are directly adjacent to each crack tip and crack wall were deficient in aluminum content. The aluminum content in the bulk γ ’ was approximately 6.6 at % and the near-crack γ ’ aluminum content ranged from 2.5-3.5 at %. The range of affected γ ’ was approximately 100 nm wide. Thu, 01 Sep 2011 00:00:00 GMT https://hdl.handle.net/1721.1/75019 2011-09-01T00:00:00Z https://hdl.handle.net/1721.1/75018 Uncertainty And Sensitivity Analysis For Long-Running Computer Codes: A Critical Review Langewisch, D. R. Fri, 01 Jan 2010 00:00:00 GMT https://hdl.handle.net/1721.1/75018 2010-01-01T00:00:00Z https://hdl.handle.net/1721.1/75017 Use of Information Theory Techniques with System Dynamics Models Middleton, Bobby D. Research was done to show how the output distribution of a system with random variables changes as the input distributions and other parameters are changed. Using Information Theory techniques, these different input and output distributions were analytically studied to try to quantify the uncertainty that exists in both the input and output distributions and to determine any relationships between the input uncertainty and output uncertainty. A simplified System Dynamics model of a generic Nuclear Power Plant Construction project was then created. The model was simple enough to allow for relative ease in analyzing data, but detailed enough to allow for changes within the model that could be interpreted as policy changes within the organization. The model was then run with various distributions for different input variables. Data was collected from these simulations for analysis. Using the results of the analytic research mentioned above, this data was analyzed to determine the feasibility of using Information Theory to enhance System Dynamics as a tool to help organizations with policy-making decisions. Results show that use of Information Theory to complement System Dynamics would be helpful in such situations. Thu, 01 Sep 2005 00:00:00 GMT https://hdl.handle.net/1721.1/75017 2005-09-01T00:00:00Z https://hdl.handle.net/1721.1/75016 A System Dynamics Model of the Energy Policymaking Process Oggianu, Stella Maris; Hansen, Kent F. Electric energy is a fundamental commodity for any aspects of the modern world. However, there are many uncertainties in the sources of electricity that are going to be used in the future. Some of these uncertainties are inherent to the electricity technologies and to the costs of fuels, but the biggest uncertainties come from the impact of future regulations and policies on capital costs, and operations and maintenance costs. Although system dynamics models have been extensively used for applications to the electric power, all the existing models are based on the supply/demand dynamics, and policies are considered as externalities. On the contrary, the energy policymaking model (the EPM model) presented in this report focuses on the complementary problem. This is, the determination of how byproducts and issues related to the adequate supply of electric energy modify the opinions and perceptions of the diverse sectors of the social/political environment; the analysis of the aspects of this environment that account for the formation of energy policies, and the assessment of how these policies are determinants of the technology used to supply electricity. The technologies considered are nuclear, fossil and windmills. The architecture of the EPM model is based on the assumption that policies are formed to minimize societal concerns regarding energy availability and price, nuclear waste, nuclear proliferation, nuclear safety, fossil emissions including greenhouse effect, acid rain, and land requirements for windmills. In this way, each technology is measured by its ability to reduce these concerns. The resulting policies impact on the economics of each of these options. At the same time, economics determines the selection of the new source of electricity. One of the most important results derived from the simulations done through the EPM model is that the revival of the nuclear industry may not be enough to prevent the increase in the production of greenhouse gases. The limited capacity of the industry to build plants is an important factor to consider. Another result is that the opening of Yucca Mountain at the earliest date means the removal of an important barrier for the future growth of the industry, as the risk premium of nuclear power plants may be reduced. Also derived from the use of the EPM model is that the electricity market should not be completely deregulated due to the likely be shortage of electricity supply, and high concerns regarding electricity availability, during peak demands. Thu, 01 Aug 2002 00:00:00 GMT https://hdl.handle.net/1721.1/75016 2002-08-01T00:00:00Z https://hdl.handle.net/1721.1/75015 Feasibility Investigations for Risk-Based Nuclear Safety Regulation Beer, B. C.; Golay, M. W.; Apostolakis, G. E. Thu, 01 Feb 2001 00:00:00 GMT https://hdl.handle.net/1721.1/75015 2001-02-01T00:00:00Z https://hdl.handle.net/1721.1/75014 CATILaC: Computer-Aided Technique for Identifying Latent Conditions User's Manual, Version 1.2 Marchinkowski, K.; Weil, R.; Apostolakis, G. A. Sat, 01 Apr 2000 00:00:00 GMT https://hdl.handle.net/1721.1/75014 2000-04-01T00:00:00Z https://hdl.handle.net/1721.1/74996 Analysis and Utilization of Operating Experience for Organizational Learning Apostolakis, G. E.; Weil, Richard The objective of this report is to clarify the ways that organizational factors influence nuclear power plant performance in order to improve performance. Therefore, this report studied the nuclear power plant organizational environment by identifying and detailing its important work processes. These work processes are: the Work Request Work Process; the Condition Reporting Work Process; the External Operating Experience Work Process; the Design Change Process; and the Procedure Change Work Process. Using this information, a methodology of incident investigation that targets organizational deficiencies contributing to events was developed. Using this methodology to analyze recent significant incidents, a list of important organizational factors and the context within which they influence the successful completion of tasks was identified. These factors are: 1) Communication - Pervasive – Most important between different units and departments; 2) Formalization -Execution; 3) Goal Prioritization - Prioritization; 4) Problem Identification - Planning, scheduling, and return to normal line-up; 5) Roles and Responsibilities - Execution; and 6) Technical Knowledge (job specific knowledge and broad based knowledge) - Job specific knowledge – execution/ Broad based knowledge –prioritization, planning, scheduling, and other tasks. Although safety culture and organizational learning are not listed, they are important. The reason for their exclusion is that they are not single organizational factors useful when cited in incident investigations. Rather, safety culture is a term used to describe all organizational factors, including organizational structure, that impact performance. Similarly, organizational learning was excluded because it is a collection of programs, processes, individual attitudes and culture responsible for learning. Although organizational learning was not listed, it was studied resulting in the development of the Utilization of Operating Experience Work Process. The Utilization of Operating Experience Work Process consists of the following seven steps: 1) Identification; 2) Screening/Prioritization/Dissemination; 3) Investigation/Evaluation; 4) Development; ii i 5) Implementation; 6) Closeout; and 7) Verification/Validation. Since prioritization was identified as important in the above work process and the analysis of significant events, a methodology for the prioritization of work activities at nuclear power plants was developed. This methodology produces a prioritization tool that assigns a numerical performance index to each item requiring prioritization. Applying the methodology at Seabrook Station produced a tool that allowed those who prioritize external operating experience to more efficiently and accurately do so. In addition to the success of the application at Seabrook, a workshop was held at MIT with experts in prioritizing external operating experience. These experts further validated the methodology and the resulting tool. The final piece of work in this report is an analysis of the NRC's revised oversight process as it relates to safety culture. The performance-based regulatory approach is appropriate for regulating safety culture. However, the NRC should continue the analysis of Fri, 01 Jun 2001 00:00:00 GMT https://hdl.handle.net/1721.1/74996 2001-06-01T00:00:00Z