RPS produce  electrical power by converting the heat generated by the natural  radioactive decay of Pu-238. NASA Selects RPS to Power Missions Based on the Agency’s Scientific Objectives and Mission Destinations, and Power Source Selections are Made Early in NASA’s Mission Review Process

According to the NASA officials we interviewed, NASA selects RPS to  power its missions based on the agency’s scientific objectives and  mission destinations. Prior to the establishment of DOE’s Supply Project in fiscal  year 2011, mission selections were influenced by the limited amount of  available Pu-238, NASA officials said. Multiple Factors Could Affect Demand for RPS and Pu-238

			Costs Associated with RPS and Missions Can Affect RPS Demand

NASA officials we interviewed said that the demand for RPS is driven by  a mission’s cost. For example, these officials said that they are reviewing a modular RPS  device. DOE Has Made Progress Reestablishing Pu- 238 Production but Faces Challenges that Could Affect Its Ability to Meet RPS and Pu-238 Demand

DOE has made progress reestablishing Pu-238 production to meet  NASA’s RPS demand, is in position to support NASA’s current plans for  solar system exploration, and anticipates being able to support two to  three RPS-powered missions per decade using new Pu-238 expected  from the Supply Project. DOE Has Made Progress Reestablishing Pu-238 Production to Meet NASA’s RPS Demand

DOE has made progress reestablishing Pu-238 production to meet  NASA’s future demand for Pu-238 to fuel RPS. DOE Faces Challenges with Key Aspects of Pu- 238 and RPS Production

DOE officials from INL, LANL, and ORNL identified several challenges  that need to be overcome for DOE to be able to meet its projected Supply  Project goal of 1.5 kg per year of Pu-238 by 2026, at the latest. According to DOE officials, DOE is still in  the experimental stage and has not perfected the chemical processing  required to extract new Pu-238 isotope from the irradiated targets, which  creates a bottleneck in the Supply Project and puts production goals at  risk. DOE officials stated that ATR must be used, as projected in DOE’s initial  plans, to reach the production goal of 1.5 kg of Pu-238 per year. However, DOE does not yet have an implementation plan under the new  constant GPHS production rate approach with milestones and interim  steps for the Supply Project or for RPS production that can be used to  show progress toward implementing efforts, show how risk is being  addressed or mitigated, or make adjustments to those efforts when  necessary. In addition, DOE’s new approach still does not improve the agency’s  ability to assess the long-term effects of the challenges associated with  Pu-238 and RPS production, such as chemical processing, availability of  reactor positions, target design and qualification, and prioritizing Pu-238  at PF-4. In addition, Standards for Internal Control in the  Federal Government states that agency management should use quality  information to achieve the entity’s objectives and communicate quality  information externally through reporting lines so that external parties can  help the entity achieve its objectives and address related risks. In  addition, DOE has identified key challenges to the Supply Project—such  as scaling up chemical processing and qualifying targets—that put  achieving Supply Project production goals at risk. However, DOE has not  fully assessed the potential long-term effects of these challenges on  production goals. While DOE officials anticipate that their new approach  to managing RPS and Pu-238 production will better help address these  challenges, DOE is in the very early stages of implementing this approach  and has not identified details, including milestones and interim steps, for  how it would address them. Recommendations for Executive Action

To help ensure the availability of Pu-238 and RPS for space exploration,  we recommend that the Secretary of Energy take the following three  actions: develop an implementation plan with milestones and interim steps for  the department’s management approach for Pu-238 and RPS  production; assess the long-term effects that known challenges may have on  production quantities, time frames, or required funding, and  communicate these potential effects to NASA; and develop a more comprehensive system to track more systemic risks,  beyond the specific technical risks identified by individual laboratories. Appendix I: Objectives, Scope, and Methodology

This report examines the National Aeronautics and Space  Administration’s (NASA) process for considering and selecting power  sources for missions, in particular the use of radioisotope power systems  (RPS), and the Department of Energy’s (DOE) ability to maintain the  necessary infrastructure and workforce for RPS and plutonium-238 (Pu- 238) production. Our objectives were to (1) describe how NASA selects  RPS for missions and what factors affect RPS and Pu-238 demand; and  (2) evaluate DOE’s progress in meeting NASA’s RPS and Pu-238  demand and what challenges, if any, DOE faces in meeting the demand.
Why GAO Did This Study

NASA uses RPS to generate electrical power in missions in which solar panels or batteries would be ineffective. RPS convert heat generated by the radioactive decay of Pu-238 into electricity. DOE maintains a capability to produce RPS for NASA missions, as well as a limited and aging supply of Pu-238 that will be depleted in the 2020s, according to NASA and DOE officials and documentation. With NASA funding, DOE initiated the Pu-238 Supply Project in 2011, with a goal of producing 1.5 kg of new Pu-238 per year by 2026. Without new Pu-238, future NASA missions requiring RPS are at risk.
GAO was asked to review planned RPS and Pu-238 production to support future NASA missions. This report (1) describes how NASA selects RPS for missions and what factors affect RPS and Pu-238 demand; and (2) evaluates DOE's progress and challenges in meeting NASA's RPS and Pu-238 demand. GAO reviewed NASA mission planning and DOE program documents, visited two DOE national laboratories involved in making new Pu-238 or RPS work, and interviewed agency officials.

What GAO Found

The National Aeronautics and Space Administration (NASA) selects radioisotope power systems (RPS) for missions primarily based on the agency's scientific objectives and mission destinations. Prior to the establishment of the Department of Energy's (DOE) Supply Project in fiscal year 2011 to produce new plutonium-238 (Pu-238), NASA officials said that Pu-238 supply was a limiting factor in selecting RPS-powered missions. After the initiation of the Supply Project, however, NASA officials GAO interviewed said that missions are selected independently of decisions on how to power them. Once a mission is selected, NASA considers power sources early in its mission review process. Multiple factors could affect NASA's demand for RPS and Pu-238. For example, high costs associated with RPS and missions can affect the demand for RPS because, according to officials, NASA's budget can only support one RPS mission about every 4 years. Expected technological advances in RPS efficiency could reduce NASA's demand for RPS and Pu-238.
DOE has made progress in reestablishing Pu-238 production to meet NASA's future demand to fuel RPS and has identified challenges to meeting its production goals. Specifically, since the start of the Supply Project, DOE has produced 100 grams of Pu-238 and expects to finalize production processes and produce interim quantities by 2019. However, DOE has also identified several challenges to meeting the Supply Project goal of producing 1.5 kilograms (kg) of new Pu-238 per year by 2026. DOE officials GAO interviewed said that DOE has not perfected the chemical processing required to extract new Pu-238 from irradiated targets to meet production goals. These officials also said that achieving the Pu-238 production goal is contingent on the use of two reactors, but only one reactor is currently qualified for Pu-238 production while the second reactor awaits scheduled maintenance. Moreover, while DOE has adopted a new approach for managing the Supply Project and RPS production—based on a constant production approach—the agency has not developed an implementation plan that identifies milestones and interim steps that can be used to demonstrate progress in meeting production goals and addressing previously identified challenges. GAO's prior work shows that plans that include milestones and interim steps help an agency to set priorities, use resources efficiently, and monitor progress in achieving agency goals. By developing a plan with milestones and interim steps for DOE's approach to managing Pu-238 and RPS production, DOE can show progress in implementing its approach and make adjustments when necessary. Lastly, DOE's new approach to managing the Supply Project does not improve its ability to assess the potential long-term effects of challenges DOE identified, such as chemical processing and reactor availability, or to communicate these effects to NASA. For example, DOE officials did not explain how the new approach would help assess the long-term effects of challenges, such as those related to chemical processing. Under Standards for Internal Control in the Federal Government , agencies should use quality information to achieve objectives and to communicate externally, so that external parties can help achieve agency objectives. Without the ability to assess the long-term effects of known challenges and communicate those effects to NASA, DOE may be jeopardizing NASA's ability to use RPS as a power source for future missions.

What GAO Recommends

GAO is making three recommendations, including that DOE develop a plan with milestones and interim steps for its Pu-238 and RPS production approach, and that DOE assess the long-term effects of known production challenges and communicate these effects to NASA. DOE concurred with GAO's recommendations.