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Wierman, T. E.

Publications and source records attributed to Wierman, T. E..

10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Enhanced Component Performance Study: Air-Operated Valves 1998–2012

This report presents an enhanced performance evaluation of air-operated valves (AOVs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2012 for the component reliability as reported in the Equipment Performance and Information Exchange (EPIX). Results (beta distributions for failure probabilities upon demand and gamma distributions for rates) are used as inputs to the U.S. Nuclear Regulatory Commission standardized plant analysis risk models of U.S. commercial nuclear power plants. The AOV failure modes considered are failure-to-open/close, failure to operate or control, and spurious operation. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. No statistically significant increasing trends were identified in the AOV results. Statistically significant decreasing trends were identified in two areas: AOV operation demands less than or equal to 20 demands per year and greater than 20 demands.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

Enhanced Component Performance Study: Turbine-Driven Pumps 1998–2012

This report presents an enhanced performance evaluation of turbine-driven pumps (TDPs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2012 for the component reliability as reported in the Equipment Performance and Information Exchange (EPIX). The TDP failure modes considered are failure to start, failure to run less than or equal to 1 hour, failure to run more than 1 hour, and (for normally running systems) failure to run. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. No statistically significant increasing trends were identified in the TDP results. Statistically significant decreasing trends were identified for TDP run hours per reactor critical year and start demands.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

Enhanced Component Performance Study: Motor-Operated Valves 1998–2012

This report presents an enhanced performance evaluation of motor-operated valves (MOVs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2012 for the component reliability as reported in the Equipment Performance and Information Exchange (EPIX). The MOV failure modes considered are failure to open/close, failure to operate or control, and spurious operation. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. No statistically significant increasing trends were identified in the MOV results. Statistically significant decreasing trends were identified for failure to open/close and operation demands.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

Enhanced Component Performance Study: Motor-Driven Pumps 1998–2012

This report presents an enhanced performance evaluation of motor-driven valves (MDPs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2012 for the component reliability as reported in the Equipment Performance and Information Exchange (EPIX). The MDP failure modes considered for standby systems are failure to start, failure to run less than or equal to 1 hour, and failure to run more than 1 hour; for normally running systems, the failure modes considered are failure to start and failure to run. An 8 hr unreliability estimate is also calculated and trended. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. One statistically significant increasing trend was identified in the MDP results for standby MDP run hours per reactor critical year. Statistically significant decreasing trends were identified for unreliability (for standby and normally running systems) frequency of failure-to-start events for standby systems and failure probability for standby systems.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

System Study: High-Pressure Safety Injection 1998–2012

This report presents an unreliability evaluation of the high-pressure safety injection system (HPSI) at 69 U.S. commercial nuclear power plants. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPSI results.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

System Study: High-Pressure Coolant Injection 1998-2012

This report presents an unreliability evaluation of the high-pressure coolant injection system (HPCI) at 69 U.S. commercial nuclear power plants. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPCI results.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

System Study: Emergency Power System 1998–2012

This report presents an unreliability evaluation of the emergency power system (EPS) at 104 U.S. commercial nuclear power plants. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. A statistically significant increasing trend was identified for unreliability (8 hour model) as a function of fiscal year. No statistically significant decreasing trend was identified in the EPS results.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

System Study: Reactor Core Isolation Cooling 1998–2012

This report presents an unreliability evaluation of the reactor core isolation cooling (RCIC) system at 31 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing trend was identified in the HPCI results. Statistically significant decreasing trends were identified for RCIC start-only and 8-hour trends.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

System Study: High-Pressure Core Spray 1998–2012

This report presents an unreliability evaluation of the high-pressure core spray (HPCS) at 8 U.S. commercial boiling water reactors. Demand, run hours, and failure data from fiscal year 1998 through 2012 for selected components were obtained from the Equipment Performance and Information Exchange (EPIX). The unreliability results are trended for the most recent 10 year period while yearly estimates for system unreliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the HPCS results.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2013

Analysis of Loss-of-Offsite-Power Events 1998–2012

Loss of offsite power (LOOP) can have a major negative impact on a power plant’s ability to achieve and maintain safe shutdown conditions. Risk analyses performed loss of all alternating current power contributes over 70% of the overall risk at some U.S. nuclear plants. LOOP event and subsequent restoration of offsite power are important inputs to plant probabilistic risk assessments. This report presents a statistical and engineering analysis of LOOP frequencies and durations at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience from fiscal year 1998 through 2012. Frequencies and durations were determined for four event categories: plant-centered, switchyard-centered, grid-related, and weather-related. The EDG failure modes considered are failure to start, failure to load and run, and failure to run more than 1 hour. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. A statistically significant increase in industry performance was identified for plant-centered and switchyard-centered LOOP frequencies. There is no statistically significant trend in LOOP durations.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗