PSAM 16 - Session W21 Overview

PSAM 16 Conference Session W21 Overview

Session Chair: Antonios Zoulis (antonios.zoulis@nrc.gov)

Paper 1 DJ234

Lead Author: Daniel Clayton

Summary of the Nuclear Risk Assessment 2019 Update for the Mars 2020 Mission Environmental Impact Statement
In the summer of 2020, the National Aeronautics and Space Administration (NASA) launched a spacecraft as part of the Mars 2020 mission. The rover on the spacecraft uses a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) to provide continuous electrical and thermal power for the mission. The MMRTG uses radioactive plutonium dioxide. NASA prepared a Supplemental Environmental Impact Statement (SEIS) for the mission in accordance with the National Environmental Policy Act. The SEIS provides information related to updates to the potential environmental impacts associated with the Mars 2020 mission as outlined in the Final Environmental Impact Statement (FEIS) for the Mars 2020 Mission issued in 2014 and associated Record of Decision (ROD) issued in January 2015. The Nuclear Risk Assessment (NRA) 2019 Update includes new and updated Mars 2020 mission information since the publication of the 2014 FEIS and the updates to the Launch Approval Process with the issuance of National Security Presidential Memorandum 20 (NSPM-20). The NRA 2019 Update addresses the responses of the MMRTG to potential accident and abort conditions during the launch opportunity for the Mars 2020 mission and the associated consequences. This information provides the technical basis for the radiological risks discussed in the SEIS. This paper provides a summary of the methods and results used in the NRA 2019 Update. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2022-1403A

Summary of the Nuclear Risk Assessment 2019 Update for the Mars 2020 Mission Environmental Impact Statement

In the summer of 2020, the National Aeronautics and Space Administration (NASA) launched a spacecraft as part of the Mars 2020 mission. The rover on the spacecraft uses a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) to provide continuous electrical and thermal power for the mission. The MMRTG uses radioactive plutonium dioxide. NASA prepared a Supplemental Environmental Impact Statement (SEIS) for the mission in accordance with the National Environmental Policy Act. The SEIS provides information related to updates to the potential environmental impacts associated with the Mars 2020 mission as outlined in the Final Environmental Impact Statement (FEIS) for the Mars 2020 Mission issued in 2014 and associated Record of Decision (ROD) issued in January 2015. The Nuclear Risk Assessment (NRA) 2019 Update includes new and updated Mars 2020 mission information since the publication of the 2014 FEIS and the updates to the Launch Approval Process with the issuance of National Security Presidential Memorandum 20 (NSPM-20). The NRA 2019 Update addresses the responses of the MMRTG to potential accident and abort conditions during the launch opportunity for the Mars 2020 mission and the associated consequences. This information provides the technical basis for the radiological risks discussed in the SEIS. This paper provides a summary of the methods and results used in the NRA 2019 Update. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2022-1403A

Paper DJ234 | Download the paper file. | Download the presentation PowerPoint file.

Name: Daniel Clayton (djclayt@sandia.gov)

Bio: Daniel Clayton is a Principal Member of the Technical Staff at Sandia National Laboratories in Albuquerque, New Mexico. He is the Project Manager of the Space Nuclear Systems Launch Safety group, simulating and predicting behavior of nuclear components during space launch accidents. Dr. Clayton received his B.S. and Ph.D. degrees in Chemical Engineering from Brigham Young University. His areas of expertise include atmospheric dispersion, computational fluid dynamics modeling, consequence analysis, launch accident sequencing, model development/coding, and risk assessments.

Country: USA
Company: Sandia National Laboratories
Job Title: Space Nuclear Launch Safety Program Manager

Paper 2 TE44

Lead Author: Teri Hamlin

Use of Preliminary PRA to Inform Decisions During Initial NASA Gateway Development
How do you use Probabilistic Risk Assessment (PRA) to support a program in development before designs are even known? Traditional PRAs require detailed design information and early in a program life cycle such information is not available. National Aeronautics and Space Administration (NASA) Safety and Mission Assurance (SMA) developed a preliminary PRA for the Gateway Program based upon NASA reference designs utilizing data and models from pervious PRA studies as surrogates for the Gateway systems. Gateway will be a lunar outpost that supports missions to the moon and includes several elements/modules developed by NASA and International Partners. NASA SMA began supporting Gateway in fall 2017 during initial formulation and continues to support the Gateway Program today. This paper will explore how the NASA SMA developed preliminary PRA was used to inform Gateway Program decisions with specific examples provided.

Use of Preliminary PRA to Inform Decisions During Initial NASA Gateway Development

How do you use Probabilistic Risk Assessment (PRA) to support a program in development before designs are even known? Traditional PRAs require detailed design information and early in a program life cycle such information is not available. National Aeronautics and Space Administration (NASA) Safety and Mission Assurance (SMA) developed a preliminary PRA for the Gateway Program based upon NASA reference designs utilizing data and models from pervious PRA studies as surrogates for the Gateway systems. Gateway will be a lunar outpost that supports missions to the moon and includes several elements/modules developed by NASA and International Partners. NASA SMA began supporting Gateway in fall 2017 during initial formulation and continues to support the Gateway Program today. This paper will explore how the NASA SMA developed preliminary PRA was used to inform Gateway Program decisions with specific examples provided.

Paper TE44 | Download the paper file. | Download the presentation PowerPoint file.

Name: Teri Hamlin (Teri.l.hamlin@nasa.gov)

Bio: Teri Hamlin is the Gateway Probabilistic Risk Assessment (PRA) Lead at Johnson Space Center (JSC). As the Gateway PRA Lead, she is responsible for development of PRA models to assess Loss of Crew (LOC) and Loss of Mission (LOM) risk for Gateway, performing risk trades as needed. Prior to joining the Gateway team Hamlin was the Commercial Crew Program (CCP) PRA lead where she initially assisted in the development of commercial crew requirements and PSA methodology and eventually provided insight into the commercial providers LOC and LOM assessments. Hamlin began her career at JSC Safety and Mission Assessment (SMA) Analysis Branch in the Shuttle Program as the Shuttle PRA Lead until Shuttle retirement following STS-135 in July 2011.

Country: USA
Company: NASA
Job Title: AST, SAFETY & MISSION ASSURANCE

Paper 3 JL65

Lead Author: James Lin

Analysis of Frequency of Aircraft Impact from Overflights
Evaluation of the frequency of aircraft impact from overflights during the in-flight phase has become more challenging in recent years due to changes in the flight paths (even for itinerary flights) and difficulty in collecting flight frequency data. In present-day aviation, airplanes can fly using the Global Positioning System (GPS) and do not always have to follow the airways. Flight paths are primarily based on the shortest routes between the origin and destination navigated by the GPS. Therefore, the frequency of enroute overflights in the airspace nearby a nuclear facility cannot be just estimated by the air traffic along the nearby airways as specified in NUREG-800, Section 3.5.1.6. All overflights within certain distance from the facility should be considered. Air traffic in the airspace nearby a nuclear facility should be estimated using the Federal Aviation Administration (FAA) records on the flights crossing specific latitude/longitude boundaries, which includes not only aircraft operations into and out of a nearby airport, but also overflights through the same airspace without landing at that airport. This paper will describe the underlying considerations in the NUREG-800 equation used for calculating the overflight impact frequency. It will also discuss in detail how the frequency of aircraft impact from enroute overflights can be analyzed considering the type of FAA data that is available. Three separate methods that have been considered for the evaluation of aircraft impact frequency (i.e., crash density, flight density, and flight hour density methods) will be described. The flight density method is an extension of the method specified in NUREG-800 for assessing the frequency of impact from flights along the nearby airways. The in-flight aircraft impact frequencies can be estimated using the FAA radar data, which is not in the form of statistics that can be readily used for the aircraft impact frequency calculation. These data from the FAA Traffic Flow Management System repository are digitalized points from the radar monitoring of the flight trajectory from airport to airport. The FAA air traffic data is processed to derive the unique overflights nearby a facility, the closest distance between the facility and each unique flight, and the frequency of these flights. In processing the FAA radar data, the closest distance between the facility and each unique flight is used to determine the lateral aircraft impact range based on the model adopted by NUREG-800. For each class of aircraft, its total frequency of crashing into a facility can be estimated by summing the products of in-flight crash rate, effective facility target area, and the inverse of lateral aircraft impact range over all unique flights. This can be calculated for several cases of the maximum closest distance, which is used to determine the appropriate area around the facility for characterizing the aircraft impact hazard.

Analysis of Frequency of Aircraft Impact from Overflights

Evaluation of the frequency of aircraft impact from overflights during the in-flight phase has become more challenging in recent years due to changes in the flight paths (even for itinerary flights) and difficulty in collecting flight frequency data. In present-day aviation, airplanes can fly using the Global Positioning System (GPS) and do not always have to follow the airways. Flight paths are primarily based on the shortest routes between the origin and destination navigated by the GPS. Therefore, the frequency of enroute overflights in the airspace nearby a nuclear facility cannot be just estimated by the air traffic along the nearby airways as specified in NUREG-800, Section 3.5.1.6. All overflights within certain distance from the facility should be considered. Air traffic in the airspace nearby a nuclear facility should be estimated using the Federal Aviation Administration (FAA) records on the flights crossing specific latitude/longitude boundaries, which includes not only aircraft operations into and out of a nearby airport, but also overflights through the same airspace without landing at that airport. This paper will describe the underlying considerations in the NUREG-800 equation used for calculating the overflight impact frequency. It will also discuss in detail how the frequency of aircraft impact from enroute overflights can be analyzed considering the type of FAA data that is available. Three separate methods that have been considered for the evaluation of aircraft impact frequency (i.e., crash density, flight density, and flight hour density methods) will be described. The flight density method is an extension of the method specified in NUREG-800 for assessing the frequency of impact from flights along the nearby airways. The in-flight aircraft impact frequencies can be estimated using the FAA radar data, which is not in the form of statistics that can be readily used for the aircraft impact frequency calculation. These data from the FAA Traffic Flow Management System repository are digitalized points from the radar monitoring of the flight trajectory from airport to airport. The FAA air traffic data is processed to derive the unique overflights nearby a facility, the closest distance between the facility and each unique flight, and the frequency of these flights. In processing the FAA radar data, the closest distance between the facility and each unique flight is used to determine the lateral aircraft impact range based on the model adopted by NUREG-800. For each class of aircraft, its total frequency of crashing into a facility can be estimated by summing the products of in-flight crash rate, effective facility target area, and the inverse of lateral aircraft impact range over all unique flights. This can be calculated for several cases of the maximum closest distance, which is used to determine the appropriate area around the facility for characterizing the aircraft impact hazard.

Paper JL65 | Download the paper file. | Download the presentation PowerPoint file.

Name: James Lin (jlin@absconsulting.com)

Bio: Mr. Lin is a senior consultant in the Irvine, California office of ABSG Consulting Inc. He has worked in the area of quantitative risk assessment and risk management for 42 years. Mr. Lin received his master degree in Nuclear Science and Engineering from University of California in Los Angeles. He has authored or co-authored more than 200 technical papers and reports.

Country: USA
Company: ABSG Consulting Inc.
Job Title: Director