NOT EVERY HYBRID BECOMES A PRIUS: THE CASE AGAINST THE FUSION-FISSION HYBRID CONCEPT

Transcription

1 NOT EVERY HYBRID BECOMES A PRIUS: THE CASE AGAINST THE FUSION-FISSION HYBRID CONCEPT IAP 2010 DON STEINER PROFESSOR EMERITUS,RPI JANUARY 22, 2010

2 IN 1997 TOYOTA INTRODUCED ITS HYBRID CAR CALLED THE PRIUS WITH ELECTRIC DRIVE

3 IN THE 1950s FORD PROPOSED ITS HYBRID CAR CALLED THE NUCLEON WITH NUCLEAR DRIVE

4 Past Experience Warns Us That The Premature Union of Two Technologies May Not Yield a Viable Hybrid Technology

5 The Essential Features of the Fusion- Fission Hybrid The hybrid consists of a fusion driver/core which is surrounded by a blanket containing fission fuel The primary fusion reaction of interest is the combination of the isotopes, deuterium and tritium, which yields an energetic neutron as one of its by- products This fusion neutron is the key to the hybrid s s potential for nuclear applications The hybrid blanket must also breed tritium in addition to accomplishing its fission objectives

6 To Assess the Potential of the Hybrid we must First Consider the Status of Both Fission and Fusion as Energy Sources

7 Over 400 Fission Reactors Operate World-Wide 7

8 The Core of a Typical Light Water Fission Reactor (LWR) Consists of Relatively Straightforward Technology 8

9 STATUS OF FISSION AS AN ENERGY SOURCE Nuclear energy is a significant contributor to U.S. and international electricity production 16% World, 20% U.S., 78% France Given the concern over carbon emissions, there may be significant growth in nuclear energy worldwide In the U.S., a once-through fuel cycle has been employed to-date Large quantities of spent fuel stored at reactor sites (no transportation, no recycle) Final waste disposal is not secured (Yucca Mountain off the table) The current approach is not sustainable in the long-term and two key issues must be addressed for the expansion of nuclear energy Waste Management Fuel Resource Management 9

10 In Brief (1) Fission is a mature energy technology which for the most part has a record of reliable and safe operation. (2) The expansion of fission energy will require solutions to the waste management and fuel resource issues. 10

11 Status Of Fusion as an Energy Source Fusion is yet to demonstrate that it can provide a reliable/safe energy source Experiments such as ITER (magnetic confinement) and NIF (inertial confinement) are key steps along the path to such a demonstration. However, significant R&D and time will be required beyond the ITER/NIF phase to establish fusion as a reliable/safe energy source 11

12 To better illustrate the status of fusion energy let us consider the situation for the Tokamak: The most mature magnetic confinement approach 12

13 The Core of the Tokamak is more Complex than that of a Fission Reactor 13

14 The Largest Operating Tokamak,The Joint European Torus (JET), is Largely a Physics Experiment

15 The Next Generation Tokamak: : International Thermonuclear Experimental Reactor (ITER) is Currently Under Construction

16 ITER has Limited Fusion Nuclear-Technology Goals First Plasma Nominal Plasma Hydrogen-Helium Complete Deuterium Complete Q=10 Long Pulse ITER CONSTRUCTION Assembly Phases 2 and 3 ITER OPERATIONS Integrated Commissioning Start Torus Pump Down Pump Down & Integrated Commissioning Magnet Commissioning Hydrogen-Helium Operations Campaign Assembly Phase 2 Assembly Phase 3 Commission, Cool & Vacuum Plasma Development and H&CD Commissioning Final Installation and Commissioning of Tritium Plant Full H&CD, TBM & Diagnostics Commissioning Deuterium Operations Campaign Deuterium-Tritium Operations Campaign Nuclear License Planned Shutdown Deuterium Operations Planned Shutdown Deuterium-Tritium Operations

17 Looking Beyond ITER (1) Following ITER,and preceding the Commercial Phase, there would be a DEMO Reactor which would demonstrate fusion nuclear technology. (2) There are Conceptual Designs for Commercial Reactors, however the details of the DEMO are yet to be defined. (3) The DEMO would be based on the same technology as a Commercial Reactor and would have to demonstrate reliable and safe operations.

18 The DEMO would operate with a lower availability than a Commercial Reactor

19 What Might the Timescale be for Practical Fusion Applications? JET first plasma occurred in June,1983 ITER first plasma is expected in 2018 (35 years following JET) The time frame for the DEMO is uncertain (how long after ITER?) Relative to fission, any practical applications of fusion energy must be viewed as very long-term

20 The Case For The Hybrid The hybrid can contribute to the expansion of nuclear energy by providing high support ratios for: Transmutation of wastes (subcritical( subcritical) Breeding fissile material (fission- suppressed) The hybrid can result in an earlier deployment of fusion than a pure-fusion power plant because: The plasma physics, technology, and engineering demands of the fusion driver are less stringent than those of a pure- fusion device Based on the above, it is argued that a hybrid-specific R&D program should be initiated now so that the hybrid option would be available in a year time frame

21 The Case Against the Hybrid The fission community has credible options for dealing with the waste and fuel supply issues The hybrid may reduce the plasma physics requirements for the fusion driver, but significant technology and engineering challenges remain beyond ITER which make an early deployment of the hybrid (25 50 years) problematic Based on the above, it is argued that it is both unnecessary and premature to initiate a hybrid specific R&D program at this point in time. In the future, fusion may be sufficiently developed to consider the hybrid as an option for the nuclear energy program

22 Why is it both unnecessary and premature to initiate a hybrid-specific R&D program at this point in time?

23 The Hybrid option is not necessary for the expansion of nuclear energy : The fission community is fully aware of the long-term issues facing expansion of nuclear energy and has identified credible options for dealing with waste and fuel supply

24 The World-Wide Fission Community is Exploring Approaches for Dealing with the Waste and Fuel Supply Issues For many decades, LWRs will be the dominant reactor type To deal with the sustainability limits of LWRs (thermal reactors), the introduction of fast reactors has been identified as an attractive option for the future expansion of nuclear power To achieve effective use of fuel resources and acceptable waste management options, the goal should be the introduction of a continuous recycle technology involving fast reactors Combined fuel cycles are under development to allow the gradual transition from thermal to fast systems 24

25 The Transition from LWRs to Fast Reactors (Robert Hill Nuclear Energy Division ANL) a Extend Uranium Resources Spent nuclear fuel will be separated into re- useable and waste materials Residual waste will go to a geological repository Uranium recycled for resource extension Fuel fabricated from recycled actinides used in recycle reactor Fuel cycle closure with repeated use in recycle reactor Recycle Used Uranium Recycle Reactor Fuel Recycled 25

26 Issues Determining The Pace of Implementation of Advanced Fission Reactors and Fuel Cycles Perceived National Need Funding Levels Policies regarding transportation, recycle, and disposition of wastes Given positive responses to the above, the advanced fission-based option could be available and implemented in about 25 years if necessary The fission-based approach could satisfy the waste and fuel needs for the foreseeable future 26

27 It is premature to launch a major hybrid R&D program at this point: The hybrid will require much of the same technology and engineering R&D required for the DEMO, but hybrid-specific R&D is not critical to the development of fusion energy 27

28 What R&D beyond ITER will be Required for the DEMO? In the EU and Japan recent activities have placed considerable attention on R&D needs and gaps beyond ITER. In 2008, DOE initiated a series of panels and workshops (ReNew) to respond to requests for a coherent fusion program plan beyond ITER to DEMO. The ARIES team began a study in 2007 to evaluate R&D needs and gaps for fusion from ITER to DEMO.

29 What were the results of the ReNeW and ARIES R&D assessments?

30 ReNeW: : DEMO Requirements Primary Requirements: Availability adequately high (A= 50-75%) and proven safety performance for the power producers to commit to building a commercial fusion plant. Supporting Requirements Integrated design: Integrated design for the fusion core components and balance of plant which provides adequate reliability, maintainability, and availability. Component reliability and maintainability: Component reliability and maintainability adequate to provide high availability. Component lifetimes: Component lifetimes adequate for achieving high availability. Inspection and maintenance system: Effective inspection and maintenance system. Many of the activities will have to be performed remotely.

31 ReNeW Conclusion: : ITER will provide valuable information for DEMO, but not all the information required, therefore substantial R&D will be needed beyond ITER

32 The Multi-Institutional ARIES Team has been Performing Fusion System Design and R&D Needs Studies for Two Decades 32

33 The ARIES Team used Technical Readiness Levels (TRLs used in Defense and other programs) to identify the R&D needs and gaps between the current status and the DEMO Power plant Proof of Principle Demo Evaluation of a Concept s Readiness TRL Issues, components or systems encompassing the key challenges Item 1 Item 2 Item 3 Etc. Basic and applied science phase

34 An R&D evaluation was performed for a DEMO based on a reference ARIES power plant in 3 broad areas TRL Power management Plasma power distribution Heat and particle flux handling High temperature and power conversion Power core fabrication Power core lifetime Safety and environment Tritium control and confinement Activation product control Radioactive waste management Reliable/stable plant operations Level completed Level in progress Plasma control Plant integrated control Fuel cycle control Maintenance

35 For this case, the ITER program contributes in some areas, but very little in others TRL PoP DEMO Power management Plasma power distribution Heat and particle flux handling High temperature and power conversion Power core fabrication Power core lifetime Safety and environment Tritium control and confinement Activation product control Radioactive waste management Reliable/stable plant operations Plasma control Plant integrated control Level completed Level in progress ITER contribution Fuel cycle control Maintenance

36 Fusion-based Component Test Facilities (CTFs) will be required to fill the gaps in order to move forward with the DEMO TRL PoP DEMO Power management Plasma power distribution Heat and particle flux handling High temperature and power conversion Power core fabrication Power core lifetime Safety and environment Tritium control and confinement Activation product control Radioactive waste management Reliable/stable plant operations Plasma control Plant integrated control Fuel cycle control Level completed Level in progress ITER contribution CTF s Maintenance

37 Much of the Technology and Engineering R&D Required for the DEMO will also be Required for the HYBRID and Includes Materials Performance Data Reliability Data Availability Data Maintainability Data Safety Data System Integration Data Component Lifetime Data Hybrid-specific R&D is not required for the DEMO and should be deferred until the practicality of fusion energy is established

38 Additional Considerations Regarding Hybrid Implementation Policy decisions on waste transportation, reprocessing, and disposition will also be required for the hybrid as well as fission to move forward Several hybrid driver options, fuel cycles and associated blankets have been proposed, some with very advanced technology no consensus exists What would it take to license a hybrid, combining fission and fusion components? International cooperation on hybrid R&D? China, Korea, and Russia have expressed interest in pursuing the hybrid political decision for the US 38

39 In Summary If the expansion of nuclear energy becomes a national priority, the fission community has credible options for dealing with the waste and fuel supply issues These options could be implemented in about 25 years and could provide viable solutions for the foreseeable future The development of a reliable/safe fusion power core is a very long-term R&D endeavor and should be the primary focus of the fusion program In the future the hybrid may offer a useful addition to the nuclear energy program, but there is no immediate need for hybrid-specific R&D

40 What Strategy Should The US Nuclear Energy Programs Pursue? A Vigorous R&D Program to Develop Fission Advanced Reactors and Fuel Cycles A Reinvigorated Fusion R&D Program Emphasizing Fusion Nuclear Technology and Addressing the Gaps Required for the DEMO The Hybrid Option Could be Revisited Once the Above Programs Have Proven Results

41 Backup Slides

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43 Providing 3 T for D-T Fusion Reactors Tritium is radioactive and decays with a halflife ~ 12.3 years and thus does not occur in our environment in sufficient quantity to provide the basis for an energy economy Therefore fusion reactors based on D-T reactions must generate (breed) the tritium they burn

44 Providing 3 T for D-T Fusion Reactors n alpha D + T blanket fusion plasma

45 Providing 3 T for D-T Fusion Reactors Thus, the fuel requirements for a D + T based fusion power economy are: Deuterium and Lithium Both of which are abundant materials