ABSG Consulting

Shillington, PA, United States

ABSG Consulting

Shillington, PA, United States

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Anderson B.T.,Boston University | Wang J.,ABSG Consulting | Salvucci G.,Boston University | Gopal S.,Boston University | Islam S.,Tufts University
Journal of Climate | Year: 2010

In this paper, the authors evaluate the significance of multidecadal trends in seasonal-mean summertime precipitation and precipitation characteristics over the southwestern United States using stochastic, chaindependent daily rainfall models. Unlike annual-mean precipitation, trends during the summertime monsoon, covering the period 1931-2000, indicate an overall increase in seasonal precipitation, the number of rainfall events, and the coverage of rainfall events in peripheral regions north of the "core" monsoon area of Arizona and western New Mexico. In addition, there is an increasing trend in intense storm activity and a decreasing trend in extreme dry-spell lengths. Over other regions of the domain, there are no discernible trends found in any of the observed characteristics. These trends are robust to the choice of start dates and, in the case of seasonal-mean precipitation, appear to persist into the current century. © 2010 American Meteorological Society.


Liming J.K.,ABSG Consulting | Reddington J.E.,CJR Engineering
International Topical Meeting on Probabilistic Safety Assessment and Analysis, PSA 2015 | Year: 2015

This paper summarizes a practical approach for human reliability analysis (HRA) performed in the context of a seismic probabilistic risk assessment (SPRA). The authors of this paper, with support from members of the FirstEnergy Nuclear Operating Company (FENOC) probabilistic risk assessment (PRA) staff and the ABSG Consulting Inc. (ABS Consulting) SPRA team, and applying the general guidance presented in the Electric Power Research Institute (EPRI) report entitled "A Preliminary Approach to Human Reliability Analysis for External Events with a Focus on Seismic," EPRI 1025294, developed and refined an SPRA HRA method, which they applied on the FENOC Davis-Besse, Perry, and Beaver Valley Units 1 and 2 SPRAs (four separate and unique nuclear power generating unit SPRAs) completed in late 2014. These four SPRAs were developed not only to respond to the requirements of U.S. Nuclear Regulatory Commission (NRC) Near-Term Task Force Recommendation 2.1 (Seismic), but also to support implementation of future risk-informed applications in accordance with the requirements stated in NRC Regulatory Guide 1.200, Revision 2, and the joint American Society of Mechanical Engineers (ASME) and American Nuclear Society (ANS) PRA Standard.


Patschke C.,ABSG Consulting
Process Safety Progress | Year: 2011

The OSHA Refinery National Emphasis Program (RNEP) and OSHA Voluntary Protection Program incorporate specific questions relative to many recognized and generally accepted good engineering practices (RAGAGEP). Many of the same RAGAGEP can be expected to be used in the OSHA Chemicals NEP as well. To comply with OSHA's process safety management (PSM) regulation and improve process safety at their sites, chemical industry personnel should be aware of what RAGAGEP OSHA is recognizing and inspecting against and their key requirements. This article will discuss: (1) OSHA's expectations for compliance with RAGAGEP, including some of the RAGAGEP OSHA references in compliance directives, instructions, and citations, (2) some citations issued by OSHA involving RAGAGEP, and (3) common RAGAGEP compliance issues ABSG Consulting observes when conducting PSM audits and assessments throughout the petrochemical and related industries. © 2011 American Institute of Chemical Engineers.


Lin J.C.,ABSG Consulting
PSAM 2014 - Probabilistic Safety Assessment and Management | Year: 2014

Due to the flammability and explosion characteristics of the propane vapor cloud, a nearby propane tank farm could possibly present a significant risk to the operation of nuclear power plants. Accidental releases of propane may occur in the propane supply pipeline, at the propane storage tanks, or on the propane transportation routes due to propane transport trailer truck accidents. Loss of containment could result in toxic vapor cloud affecting the nearby nuclear plant control room habitability, Vapor Cloud Explosion (VCE) overpressure due to both deflagration and detonation, Boiling Liquid Expanding Vapor Explosion (BLEVE) missile impacts, and thermal radiation from BLEVE fireballs, flash fires, pool fires, and jet fires. The thermal radiation impact ranges of a pool fire, jet fire, flash fire, and BLEVE fireball is typically less than the shortest distance between the propane tank farm and the nearby nuclear plant. The explosion overpressure and missiles are the most critical hazards to the nearby nuclear plants. Only VCE overpressure greater than 1 psi and BLEVE missiles can potentially impact the PRA related structures and equipment at the nearby nuclear plant. The total frequency of unacceptable damage at the nearby nuclear plant resulting from accidents at the propane tank farm and from propane transport truck accidents is estimated to be less than 10-7 per year. This paper discusses the insights gained from the analysis of the risk impact on a nearby nuclear plant due to accidental release of propane from the propane terminal related operations, including the propane storage/distribution facility and the propane transport trucks. The important considerations used in the analysis of the risk scenarios resulting from a propane transport truck accident, large and small releases at the propane distribution facility, and exploding missile hazards are presented.


Lin J.C.,ABSG Consulting
International Topical Meeting on Probabilistic Safety Assessment and Analysis 2013, PSA 2013 | Year: 2013

The risk of spent fuel pool (SFP) fire that may result from SFP leaks or other loss of inventory events is evaluated. The frequency of uncovery of spent fuel is estimated as a surrogate for the risk of spent fuel fire. The analysis includes both internal and external initiating events that may occur during power operation and during outage. The four categories of initiating events considered are: loss of SFP cooling, loss of SFP inventory, loss of offsite power, events that may cause catastrophic failure of the SFP structure, including earthquakes, tornado-generated missiles, aircraft crashes, and heavy load drops. The possible evolutions involved in the process from shutdown, reactor disassembly, fuel movement, to reactor reassembly are grouped into three general configurations: SFP to transfer canal gate installed, SFP to transfer canal gate removed and fuel transfer tube (FTT) isolation valve closed, and SFP to transfer canal gate removed and FTT isolation valve open. The dominant contributor to the frequency of uncovery of spent fuel stored in the SFP is seismic events. Power operation has the highest frequency of spent fuel uncovery among the different plant configurations because it has the longest duration compared to the outage configurations. Among the three outage configurations, the two configurations with the SFP gate installed or FTT isolated have greater contributions to the frequency of spent fuel uncovery, also because of the longer duration compared to the outage configuration in which the FTT is open.


Lin J.C.,ABSG Consulting
PSAM 2014 - Probabilistic Safety Assessment and Management | Year: 2014

Because the probable maximum events selected in FSAR for nuclear plants may not be the maximum possible events, they could possibly be exceeded by more severe events in the future. As such, there is a need to re-evaluate the other external hazards, especially those associated with the natural phenomena. To ensure that the maximum possible intensities of the natural phenomenon hazards are identified and analyzed, one has to be able to identify the physical limits of the parameters that define the intensities of the hazards. However, in some cases, it is truly difficult to identify the absolute, physical limits of parameters associated with selected natural hazards. One way to address the issue of exceeding the probable maximum event is to evaluate the quantitative risk in terms of core damage and large early release frequencies resulting from the specific hazard of concern. This will require the estimation of the hazard frequency. While it may be possible to assess the occurrence frequencies of selected natural phenomena of limited intensity, the uncertainty in the assessed frequencies of events with magnitude beyond the range of historical occurrences may be uncomfortably high. Furthermore, some of the external hazards may not lend themselves to an easy assessment of their occurrence frequencies. As such, deterministic criteria will still need to be used for the risk evaluation of selected hazard events. This paper groups the entire set of other external hazards into a number of categories and discusses the characteristics, PRA evaluation methods, and other aspects of each of these groups.


Lin J.C.,ABSG Consulting
International Topical Meeting on Probabilistic Safety Assessment and Analysis, PSA 2015 | Year: 2015

Relays are typically not structurally damaged during a seismic event. However, due to the low seismic ruggedness of the relay contacts, vibration induced actuation of certain relays could occur during an earthquake potentially resulting in an undesired equipment operation or change in equipment position/state. Relay chatter could also actuate the lockout devices associated with the supply breakers for essential buses and the emergency diesel generator (EDG) output breakers, thus requiring manual operator reset before these breakers can be re-closed. The most vulnerable portion of the control circuits that may cause the adverse effects of seismic relay chatter Include the seal-in function of motor-operated valves, seal-in feature of time overcurrent trips for medium voltage electrical loads (e.g., pumps and other medium voltage bus breakers), lockout design of the supply breakers for essential buses and the EDG output breakers. Most of the non-relay contact devices are not prone to chatter. However, mercury and sudden pressure switches on large power transformers, and small sensitive operator micro switches should still be evaluated in the seismic relay chatter analysis. These devices are typically located in the control circuits for the non-essential equipment, and therefore not likely to cause adverse impact on accident mitigation equipment, except for the potential lockout of auxiliary transformers and possible loss of offsite power resulting from the activation of sudden pressure relays due to earthquake induced pressure pulses. © 2015 by the American Nuclear Society.


Liming J.K.,ABSG Consulting
International Topical Meeting on Probabilistic Safety Assessment and Analysis, PSA 2015 | Year: 2015

This paper summarizes a practical approach for creating the technical infrastructure required to support effective and efficient implementation of risk-informed performance-based applications (RIPBAs) using probabilistic safety assessment (PSA) or probabilistic risk assessment (PRA) as a foundation. RIPBAs provide a way for nuclear utilities to leverage some of the substantial investments they have made in developing PSAs to reap significant cost savings over the remaining lives of their power plants. RIPBAs include programs that require approval from one or more regulators, as well as applications that require no approval or monitoring from organizations outside the utility company. Some examples of cost-saving RIPBAs include: • Industry Initiative 4B - Risk-Managed Technical Specifications (RMTS) Programs • Industry Initiative 5B - Risk-Informed Surveillance Frequency (RI-SFCP) Control Programs • 10 CFR 50.69 - Risk-Informed Graded Quality Assurance (RI-GQA) Programs • Risk-Informed In-Service Inspection (RI-ISI) Programs (e.g., for piping) • Risk-Informed In-Service Testing (RI-IST) Programs • Risk-Informed Containment Integrated and Local Leak Rate Testing • Risk-Informed Fire Protection Programs (e.g., National Fire Protection Association [NFPA] 805 Implementation) • GSI-191 (Containment Sump Issue) Resolution Support • Risk-Informed Plant Security Management Programs • Risk-Informed Performance-Based Asset Management (RIPBAM). © 2015 by the American Nuclear Society.


Hanchey K.,ABSG Consulting
Process Safety Progress | Year: 2010

OSHA has recently emphasized an added commitment to do more Refinery and Chemical National Emphasis Program inspections. This article outlines company methods to (a) limit exposure and expense by supplying the agency with requested information, (b) minimize site disruptions, and (c) make compliance improvements efficiently. A successful inspection requires the development of a strategy, tactics, teams, procedures, interview process, and general management of the inspection process. © 2010 American Institute of Chemical Engineers.


Lin J.C.,ABSG Consulting
11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, PSAM11 ESREL 2012 | Year: 2012

Earthquake is a key risk contributor to petrochemical/chemical plants due to the potential release of hazardous materials from the process systems. Risk analysis typically analyzes the consequences of hazardous releases by performing dispersion analysis and assessing the resulting fatalities. For each scenario, it identifies a release point and defines the release rate for the consequence analysis. For seismic events, releases may result from more than one piece of equipment due to ruptures of equipment of different types or correlated ruptures of components of the same/similar type. Since both involve simultaneous breaches and releases from multiple pieces of equipment, it is important that the consequence analysis accounts for the combined impact of these simultaneous releases due to the possible synergetic and threshold effects. Given that the seismic force has caused multiple breaches and releases from more than one piece of equipment at different locations, the consequence analysis of releases from more than one source must account for the collective releases from all simultaneous release sources. However, the current consequence analysis software can only model single-point releases. As such, the release rates from multiple release sources need to be combined and treated as if from a single source. To be conservative, the surrogate release point can either be the most conservative release location or a location from which the combined release can produce an impact range that envelops the impact ranges from the individual releases, especially in the direction toward the population centers. Without accounting for the combined release from multiple sources, the consequence would be underestimated. This is because, for example, when the plumes from multiple release points eventually join, the combined concentration could potentially cause more fatalities than the sum of what each can produce individually. Part of this is because of the threshold effect. Copyright © (2012) by IAPSAM & ESRA.

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