Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 1
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 338 SUMMARY 339 The potential for using fusion energy to produce commercial electric power was first 340 explored in the 1960s. Harnessing fusion energy offers the prospect of a nearly- 341 carbon-free energy source with a virtually unlimited supply of fuel (derived from 342 deuterium in water) and, unlike nuclear fission plants, fusion power plants, if 343 appropriately designed, would not produce large amounts of high-level nuclear waste 344 requiring long-term disposal. These prospects induced many nations around the world 345 to initiate R&D programs aimed at developing fusion as an energy source. Two 346 alternative approaches are being explored: magnetic fusion energy (MFE) and inertial 347 fusion energy (IFE). This report assesses the prospects for IFE, although there are 348 some elements common to the two approaches. Recognizing that the practical 349 realization of fusion energy remains decades away, the committee judges that the 350 potential benefits of inertial fusion energy justify it as part of the long-term U.S. 351 energy R&D portfolio. 352 To initiate fusion, the deuterium and tritium fuel must be heated to over 50 million 353 degrees and held together for long enough for the reactions to take place (see 354 Appendix A). The prospects for making inertial fusion a commercial energy source 355 depend on the ability to implode a fuel target to a high enough temperature and 356 pressure to initiate a fusion reaction that releases on the order of 100 times more 357 energy than was delivered to the target. 358 The current U.S. fleet of inertial fusion facilities offers a unique opportunity to 359 experiment at “fusion scale” where fusion conditions are accessible for the first time. 360 Indeed, significant fusion burn is expected on the National Ignition Facility in this 361 decade. A key aim of this study is to determine how best to exploit this opportunity to 362 advance the science and technology of inertial fusion energy (IFE). 363 364 Current R&D Status 365 U.S. research on inertial confinement fusion (ICF)—the basis for inertial fusion 366 energy—has been supported by the National Nuclear Security Administration 367 (NNSA) primarily for nuclear-weapons stockpile stewardship applications. This 368 research has benefitted inertial fusion for energy applications, because the two share 369 many common physics challenges. 370 The principal research efforts in the United States are aligned along the three major 371 energy sources for driving the implosion of inertial confinement fusion fuel pellets. 372 These are: (1) lasers (including solid state lasers at the Lawrence Livermore National 373 Laboratory’s National Ignition Facility and the University of Rochester’s Laboratory 1
OCR for page 2
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 374 for Laser Energetics, as well as the krypton fluoride gas lasers at the Naval Research 375 Laboratory; (2) particle beams, being explored by a consortium of laboratories led by 376 the Lawrence Berkeley National Laboratory; and (3) pulsed magnetic fields, being 377 explored on the Z machine at Sandia National Laboratory. 378 There has been substantial scientific and technological progress in inertial 379 confinement fusion during the past decade. 1 Despite these advances, the minimum 380 technical accomplishment that would give confidence that commercial IFE may be 381 feasible—the ignition 2 of a fuel pellet in the laboratory—has not been achieved as of 382 this writing. 3 383 For the first time a research facility, the National Ignition Facility4 (NIF) at Lawrence 384 Livermore National Laboratory, conducted a systematic campaign at an energy scale 385 that was projected to be sufficient to achieve ignition. The anticipated achievement of 386 ignition at NIF motivated the U.S. Department of Energy (DOE) to request that the 387 National Research Council review the prospects for inertial fusion energy in a report 388 with the following statement of task: 389 • Assess the prospects for generating power using inertial confinement fusion; 390 • Identify scientific and engineering challenges, cost targets, and R&D 391 objectives associated with developing an IFE demonstration plant; and 392 • Advise the U.S. Department of Energy on its development of an R&D 393 roadmap aimed at creating a conceptual design for an inertial fusion energy 394 demonstration plant. 395 A comparison of inertial fusion energy to magnetic fusion energy or any other 396 potential or available energy technologies (such as wind or nuclear fission), while a 397 very interesting subject of study, was also outside the committee’s purview. 398 There has been significant technical progress during the past year in the National 399 Ignition Campaign being carried out on the NIF. Nevertheless, ignition has taken 400 longer than scheduled. The results of the experiments performed to date have 401 differed from model projections and are not yet fully understood. It will likely take 402 significantly more than a year from now to gain a full understanding of the 403 discrepancies between theory and experiment and to make needed modifications to 1 Three major energy sources for driving the implosion of inertial fusion energy fuel pellets are discussed in this report. These are lasers (including solid state lasers and krypton fluoride gas lasers), particle beams, and pulsed magnetic fields. 2 In this report, ignition is defined as “scientific breakeven” in which the target releases an amount of energy equal to the energy incident upon it to drive the implosion. 3 As of December 27, 2012. 4 The National Ignition Facility, which was designed for stockpile stewardship applications, currently uses a solid-state laser driver and an indirect-drive target configuration. 2
OCR for page 3
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 404 optimize target performance. 5 Box 1.2 in Chapter 1 entitled “Recent Results From 405 the National Ignition Facility” provides a detailed discussion of the most recent 406 results from the National Ignition Facility, and Appendix I provides a more technical 407 discussion of this subject. 408 409 While the committee considers the achievement of ignition as an essential 410 prerequisite for initiating a national, coordinated, broad-based inertial fusion energy 411 program, the committee does not believe that the fact that NIF did not achieve 412 ignition by the end of the National Ignition Campaign on September 30, 2012 lessens 413 the long-term technical prospects for inertial fusion energy. It is important to note that 414 none of the expert committees 6 that reviewed NIF’s target performance concluded 415 that ignition would not be achievable at the facility. Furthermore, as the ICF Target 416 Physics Panel concluded, “So far as target physics is concerned, it is a modest step 417 from NIF scale to IFE scale. 7” A better understanding of the physics of indirect-drive 418 implosions is needed, as well as improved capabilities for simulating them. In 419 addition, alternative implosion modes (laser direct drive, shock ignition, heavy-ion 420 drive, and pulsed power drive) have yet to be adequately explored. It will therefore 421 be critical that the unique capabilities of the National Ignition Facility be used to 422 determine the viability of ignition at the million joule energy scale. 423 424 As the scientific basis for inertial fusion energy is better understood, —e.g., ignition 425 is achieved, or the conditions for ignition are better understood—the path forward for 426 inertial fusion energy research will diverge from NNSA’s weapons research program 427 as technologies specific to inertial fusion energy (e.g., high-repetition-rate driver 428 modules, chamber materials, mass-producible targets) will need to receive a higher 429 priority. 430 PRINCIPAL CONCLUSIONS AND RECOMMENDATIONS 431 432 With substantial input from the community, the committee conducted an intensive 433 review of approaches to inertial fusion energy (diode-pumped lasers, krypton fluoride 5 National Nuclear Security Administration, “NNSA’s Path Forward to Achieving Ignition in the Inertial Confinement Fusion Program: Report to Congress” December, 2012. 6 Department of Energy, Memo by D. H. Crandall to D. L. Cook, “External Review of the National Ignition Campaign,” July 19, 2012; National Ignition Campaign Technical Review Committee, “The National Ignition Campaign Technical Review Committee Report, For the Meeting Held on May 30 through June 1, 2012;” National Research Council, “Assessment of Inertial Confinement Fusion Targets,” The National Academies Press, Washington, D.C., 2012. 7 See Overarching Conclusion 1 from the ICF Target Physics Panel’s report. 3
OCR for page 4
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 434 lasers, heavy-ion accelerators, pulsed power; as well as indirect drive 8 and direct 435 drive 9). The committee’s principal conclusions and recommendations regarding its 436 assessment of the prospects for inertial fusion energy are given below. They are 437 grouped thematically under several general topic headings. A broader set of 438 conclusions and recommendations is contained in the individual chapters. Where 439 there is an overlap, the conclusions and recommendations are numbered as they 440 appear in the chapters, to point the reader to the location of more detailed discussion. 441 The recommendations are made in view of the current technical uncertainties and the 442 anticipated long timeframe to achieve commercialization of IFE. 443 444 445 Potential Benefits, Recent Progress, and Current Status of Inertial Fusion 446 Energy 447 448 Conclusion: The scientific and technological progress in inertial confinement fusion 449 has been substantial during the past decade, particularly in areas pertaining to the 450 achievement and understanding of high-energy-density conditions in the compressed 451 fuel, and in exploring several of the critical technologies required for inertial fusion 452 energy applications (e.g., high-repetition-rate lasers and heavy-ion-beam systems, 453 pulsed-power systems, and cryogenic target fabrication techniques). (Conclusion 1 454 from the Interim Report; Chapters 2 and 3 of this report) 455 456 Conclusion: It would be premature to choose a particular driver approach as the 457 preferred option for an inertial fusion energy demonstration plant at the present time. 458 (Conclusion 2 from the Interim Report) 459 460 Conclusion: The potential benefits of inertial confinement fusion energy (abundant 461 fuel, minimal greenhouse gas emissions, limited high-level radioactive waste 462 requiring long-term disposal) also provide a compelling rationale for establishing 463 inertial fusion energy R&D as part of the long-term U.S. energy R&D portfolio. A 464 portfolio strategy hedges against uncertainties in future availability of alternatives 465 due, for instance, to unforeseen circumstances. (Conclusion 1-1) 466 467 Factors Influencing the Commercialization of Inertial Fusion Energy 468 469 Conclusion: The cost of targets has a major impact on the economics of inertial 470 fusion energy power plants. Very large extrapolations are required from the current 471 state-of-the-art for fabricating targets for inertial confinement fusion research to the 472 ability to mass-produce inexpensive targets for inertial fusion energy systems. 473 (Conclusion 3-24) 8 In an indirect-drive target, the driver energy strikes the inner surface of a hollow chamber (the “hohlraum”) that surrounds the fuel capsule, exciting X-rays that transfer energy to the capsule. 9 In a direct-drive target, the driver energy strikes directly on the fuel capsule. The illumination geometry of the driver beams may be oblique (e.g. from diametrically opposite sides, called “polar direct drive”) or spherically symmetric. 4
OCR for page 5
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 474 475 Conclusion: As presently understood, an inertial fusion energy power plant would 476 have a high capital cost. Such plants would have to operate with a high availability. 477 Achieving high availabilities is a major challenge for fusion energy systems. This 478 would involve substantial testing of IFE plant components and the development of 479 sophisticated remote maintenance approaches. (Conclusion 3-23) 480 481 Recommendation: Economic analyses of inertial fusion energy power systems 482 should be an integral part of national program planning efforts, particularly as more 483 cost data become available. (Recommendation 3-10) 484 485 Recommendation: A comprehensive, systems engineering approach should be used 486 to assess the performance of IFE systems. Such analyses should also include the use 487 of a Technology Readiness Levels (TRL) methodology to help guide the allocation of 488 R&D funds. (Recommendation 3-11) 489 490 Conclusion: Some licensing/regulatory-related research has been carried out for the 491 ITER (magnetic fusion energy) program, and much of that work provides insights 492 into the licensing process and issues for inertial fusion energy. The Laser Inertial 493 Fusion Energy (LIFE) program at Lawrence Livermore National Laboratory has 494 considered licensing issues more than any other IFE approach; however, much more 495 effort would be required when a Nuclear Regulatory Commission license is pursued 496 for inertial fusion energy. (Conclusion 3-20) 497 498 499 The Establishment of an Integrated National Inertial Fusion Energy Program 500 and Its Characteristics 501 502 Conclusion: While there have been diverse past and ongoing research efforts 503 sponsored by various agencies and funding mechanisms that are relevant to IFE, at 504 the present time there is no nationally coordinated research and development program 505 in the United States aimed at the development of inertial fusion energy that 506 incorporates the spectrum of driver approaches (diode-pumped lasers, heavy ions, 507 krypton fluoride (KrF) lasers, pulsed power, or other concepts), the spectrum of target 508 designs, or any of the unique technologies needed to extract energy from any of the 509 variety of driver and target options. (Conclusion 4-9) 510 511 Conclusion: Funding for inertial confinement fusion is largely motivated by the U.S. 512 nuclear weapons program, due to its relevance to stewardship of the nuclear stockpile. 513 The National Nuclear Security Administration (NNSA) does not have an energy 514 mission and--in the event that ignition is achieved--the NNSA and inertial fusion 515 energy (IFE) research efforts will continue to diverge as technologies relevant to IFE 516 (e.g., high-repetition-rate driver modules, chamber materials, mass-producible 517 targets) begin to receive a higher priority in the IFE program. (Conclusion 4-10) 518 5
OCR for page 6
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 519 Conclusion: The appropriate time for the establishment of a national, coordinated, 520 broad-based inertial fusion energy program within DOE is when ignition is achieved. 521 (Conclusion 4-13) 522 523 Conclusion: At the present time, there is no single administrative home within the 524 Department of Energy that has been invested with the responsibility for administering 525 a National Inertial Fusion Energy R&D program. (Conclusion 4-16) 526 527 Recommendation: In the event that ignition is achieved on the National Ignition 528 Facility or another facility, and assuming that there is a federal commitment to 529 establish a national inertial fusion energy R&D program, the Department of Energy 530 should develop plans to administer such a national program (including both science 531 and technology research) through a single program office. (Recommendation 4-11) 532 533 Recommendation: The Department of Energy should use a milestone-based 534 roadmap approach, based on Technology Readiness Levels (TRLs), to assist in 535 planning the recommended national IFE program leading to a DEMO plant. The 536 plans should be updated on a regular basis to reassess each potential approach and set 537 priorities based on the level of progress. Suitable milestones for each driver-target 538 pair considered might include, at a minimum, the following technical goals: 539 1. Ignition 540 2. Reproducible modest gain 541 3. Reactor-scale gain 542 4. Reactor-scale gain with a cost-effective target 543 5. Reactor-scale gain with the required repetition rate (Recommendation 4-4) 544 545 Recommendation: The national inertial fusion energy technology effort should 546 leverage magnetic fusion energy materials and technology development in the United 547 States and abroad. Examples include: the ITER test blanket module R&D program, 548 materials development, plasma-facing components, tritium fuel cycle, remote 549 handling, and fusion safety analysis tools. (Recommendation 3-2) 550 551 552 Inertial Fusion Energy Drivers 553 554 Conclusion: There are potential advantages and uncertainties in target design as well 555 as different driver approaches to the extent that the question of “the best driver 556 approach” remains open. (Conclusion 4-5) 557 558 Laser Drivers 559 560 Conclusion: If the diode-pumped, solid-state laser technical approach is selected for 561 the roadmap development path, the demonstration of a diode-pumped, solid-state 562 laser beam-line module and line-replaceable-unit at full scale is a critical step toward 563 laser driver development for IFE. (Conclusion 2-2) 564 6
OCR for page 7
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 565 Conclusion: If the KrF laser technical approach is selected for the roadmap 566 development path, a very important element of the KrF laser inertial fusion energy 567 research and development program would be the demonstration of a multi-kJ, 5−10- 568 Hz, KrF laser module that meets all of the requirements for a Fusion Test Facility. 569 (Conclusion 2-6) 570 571 Heavy-Ion-Beam Drivers 572 573 Conclusion: Demonstrating that the Neutralized Drift Compression Experiment-II 574 (NDCX-II) meets its energy, current, pulse length, and spot-size objectives is of great 575 technical importance, both for heavy-ion inertial fusion energy applications and for 576 high-energy-density physics. (Conclusion 2-7) 577 578 Conclusion: Restarting the High-Current Experiment to undertake driver-scale beam 579 transport experiments, and restarting the enabling technology programs are crucial to 580 re-establishing a heavy-ion fusion program. (Conclusion 2-8) 581 582 Pulsed-Power Drivers 583 584 Conclusion: There has been considerable progress in the development of efficient 585 pulsed-power drivers of the type needed for inertial confinement fusion applications, 586 and the funding is in place to continue along that path. (Conclusion 2-12) 587 588 Conclusion: The major technology issues that would have to be resolved to make a 589 pulsed-power IFE system feasible—the recyclable transmission line and the ultra- 590 high-yield chamber technology development—are not receiving any significant 591 attention. (Conclusion 2-14) 592 593 Recommendation: Physics issues associated with the MagLIF concept should be 594 addressed in single-pulse mode during the next five years so as to determine its 595 scientific feasibility. (Recommendation 2-2) 596 597 Recommendation: Technical issues associated with the viability of recyclable 598 transmission lines and 0.1 Hz, 10-GJ-yield chambers should be addressed with 599 engineering feasibility studies in the next five years to assess the technical feasibility 600 of MagLIF as an inertial fusion energy system option. (Recommendation 2-3) 601 602 Other Critical Technologies for Inertial Fusion Energy 603 604 Conclusion: Significant IFE technology research and engineering efforts are required 605 to identify and develop solutions for critical technology issues and systems, such as: 606 targets and target systems; reaction chambers (first wall/blanket/shield); materials 607 development; tritium production, recovery and management systems; environment 608 and safety protection systems; and economics analysis. (Conclusion 3-3) 609 610 Target Technologies 7
OCR for page 8
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 611 612 Conclusion: An inertial fusion energy program would require an expanded effort on 613 target fabrication, injection, tracking, survivability and recycling. Target 614 technologies developed in the laboratory would need to be demonstrated on industrial 615 mass production equipment. A target technology program would be required for all 616 promising inertial fusion energy options, consistent with budgetary constraints. 617 (Conclusion 3-9) 618 619 Chamber Technologies 620 621 Conclusion: The chamber and blanket are critical elements of an inertial fusion 622 energy power plant, providing the means to convert the energy released in fusion 623 reactions into useful applications, as well as the means to breed the tritium fuel. The 624 choice and design of chamber technologies are strongly coupled to the choice and 625 design of driver and target technologies. A coordinated development program is 626 needed. (Conclusion 3-10) 627 628 The National Ignition Facility 629 630 Conclusion: The National Ignition Facility (NIF), designed for stockpile stewardship 631 applications, is also of great potential importance for advancing the technical basis for 632 inertial fusion energy (IFE) research. (Conclusion 4-15) 633 634 Conclusion: There has been good technical progress during the past year in the 635 ignition campaign carried out on the National Ignition Facility. Nevertheless, ignition 636 has been more difficult than anticipated and has not been achieved in the National 637 Ignition Campaign that ended on September 30, 2012. The experiments to date are 638 not fully understood. It will likely take significantly more than a year to gain a full 639 understanding of the discrepancies between theory and experiment and to make 640 needed modifications to optimize target performance. (Conclusion 2-1) 641 642 Recommendation: The target physics programs on NIF, Nike, OMEGA, and Z 643 should receive continued high priority. The program on NIF should be expanded to 644 include direct drive and alternate modes of ignition. It should aim for ignition with 645 moderate gain and comprehensive scientific understanding leading to predictive 646 capabilities of codes for a broad range of IFE targets. (Recommendation 2-1) 647 648 Recommendation: The achievement of ignition with laser-indirect drive at the 649 National Ignition Facility should not preclude experiments to test the feasibility of 650 laser-direct drive. Direct drive experiments should also be carried out because of the 651 potential of achieving higher gain and/or other technological advantages. 652 (Recommendation 4-7) 653 654 Recommendation: Planning should begin for making effective use of the National 655 Ignition Facility as one of the major program elements in an assessment of the 8
OCR for page 9
PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION 656 feasibility of inertial fusion energy. (Recommendation from interim report and 657 Recommendation 4-10 from this report) 658 659 Proliferation Risks 660 661 The NRC Panel on the Assessment of Inertial Confinement Fusion Targets has 662 examined the proliferation risks associated with inertial confinement fusion systems, 663 and the panel’s analysis and principal conclusions regarding proliferation risks are 664 presented in Chapter 3 of the panel’s report. The NRC Committee on the Prospects 665 for Inertial Confinement Fusion Energy Systems concurs with the Panel’s 666 conclusions, which are reiterated below for completeness. 667 668 Conclusion: At present, there are more proliferation concerns associated with 669 indirect-drive targets than with direct-drive targets. However, worldwide technology 670 developments may eventually render these concerns moot. 10 Remaining concerns are 671 likely to focus on the use of classified codes for target design. (Conclusion 3-1 from 672 the panel report) 673 674 Conclusion: The nuclear weapons proliferation risks associated with fusion power 675 plants are real, but are likely to be controllable. 11 These risks fall into three 676 categories: knowledge transfer; Special Nuclear Material (SNM) production; and 677 tritium diversion. (Conclusion 3-2 from the panel report) 678 679 Conclusion: Research facilities are likely to be a greater proliferation concern than 680 power plants. A working power plant is less flexible than a research facility, and it is 681 likely to be more difficult to explore a range of physics problems with a power plant. 682 However, domestic research facilities (which may have a mix of defense and 683 scientific missions) are more complicated to put under international safeguards than 684 commercial power plants. Furthermore, the issue of proliferation from research 685 facilities will have to be dealt with long before proliferation from potential power 686 plants becomes a concern. (Conclusion 3-3 from the panel report) 687 688 Conclusion: It will be important to consider international engagement regarding the 689 potential for proliferation associated with IFE power plants. (Conclusion 3-4 from 690 the panel report) 691 692 10 Progress in experiment and computation may eventually result in data, simulations, and knowledge that the U.S. presently considers classified becoming widely available. Classification concerns about different kinds of targets may then change considerably. 11 Proliferation of knowledge and Special Nuclear Material production are subject to control by international inspection of research facilities and plants; tritium diversion is a problem that will require careful attention. 9