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PREPUBLICATION COPY--SUBJECT TO FURTHER EDITORIAL CORRECTION
7249
7250 Appendix J
7251
7252 Detailed Discussion of Technology Applications Event Profiles
7253
7254 The following narratives will indicate the steps required for each TA to reach the starting
7255 point of the DEMO conceptual design. Conceptual design of DEMO reactors will depend
7256 upon one or more TAs successfully achieving TRLs of 6 for each component of that TA
7257 “package.” The specific steps are meant to be illustrative of the conditional requirements
7258 that DOE should set down in its planning process—requirements that should be regularly
7259 updated based on scientific and technological progress.
7260
7261 Laser IFE Events-Based Roadmap to DEMO (TA-1)
7262
7263 In addition to the target gain and laser efficiency demonstrations required before
7264 operation of an FTF or design of a DEMO reactor, additional detailed pre-conditions
7265 are required for each of three main laser IFE candidate technology applications
7266 (TA's).
7267
7268 Indirect Drive Target with Diode-Pumped Laser: Pre-conditions for FTF or
7269 DEMO
7270
7271 1a. In the present National Ignition Facility (NIF) indirect drive campaign, if
7272 1
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7295
7296 Direct Drive Target with Diode-Pumped Laser: Pre-conditions for FTF or
7297 DEMO
7298
7299 As with indirect drive, the diode-pumped laser will be optically very similar to the
7300 flashlamp-pumped NIF laser, and so laser performance on NIF will define future
7301 expectations in direct drive with a diode-pumped laser.
7302
7303 Regardless of the outcome on indirect drive, even in the case that reactor-scale gain is
7304 achieved (1a above), the NIF laser should be used to study direct drive targets as
7305 planned.
7306
7307 Polar direct drive (PDD) is an interim approach to spherical direct drive that employs
7308 the existing NIF beam ports. However, ignition with PDD is uncertain due to likely
7309 laser plasma instability (LPI) differences between the "equatorial" and more polar
7310 beams. Polar direct drive may be a valid test-bed for a preview of spherical direct
7311 drive interactions on the NIF laser.
7312
7313 2a. In event 1b above, with G<1 in indirect drive at the end of the ignition
7314 campaign, NIF should be upgraded as planned for polar direct drive studies (2017)
7315 with beam smoothing (estimated $30M for materials) and employed in a study of
7316 polar direct drive physics at reactor plasma scale size. If modeling of the results with
7317 validated codes points to likely G>1 with spherical direct drive, NIF should be re-
7318 configured at the earliest opportunity to a true SDD configuration (estimated $300M).
7319
7320 2b. If 1
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7341 There is not an ignition-level facility available at the KrF wavelength of 248nm with
7342 bandwidth of 3THz. However, calculations presented to the committee based upon
7343 spherical direct drive predict the lowest energy threshold for ignition to occur with
7344 KrF. These calculations are plausible because of the higher LPI threshold of KrF by a
7345 factor of 2 compared to 3ω thresholds at 351nm. This potential benefit of KrF
7346 suggests that, if reactor-scale gain of 140 is achieved under heading 2b above, cost
7347 effective power generation could be possible with KrF-driven IFE.
7348
7349 Prior to construction and operation of a 400-500kJ KrF laser FTF for the exploration
7350 of spherical direct drive physics with reactor-scale targets at 248nm, the committee
7351 suggests the following list of pre-conditions to maximize the chance that power
7352 generation by KrF-driven, direct-drive IFE will be cost competitive.
7353
7354 3a. A single shot 15-25kJ KrF beamline operates at 0.01Hz with the desired pulse
7355 shape, focal uniformity and zooming (~20 copies of this beamline would drive the
7356 facility).
7357
7358 3b. The NRL Electra repetitive test of a 500J KrF laser at 5Hz runs for >107
7359 pulses with efficiency of >6 percent and a clear projection of the same technology to
7360 the 15-25kJ module at >109 pulses.
7361
7362 3c. Experimental evidence validates some aspects of high gain (>140) in 2D(+)
7363 calculations that include the most advanced validated models of laser plasma
7364 interaction at 248nm, and incorporate learning from SDD experiments on NIF.
7365
7366 3d. A chamber design exists that projects to >108 pulses with the threat spectrum
7367 of direct drive targets, to include a plausible final optics design, and that direct drive
7368 targets can be injected into the chamber and engaged by the laser at >5 Hz rate.
7369
7370 3e. Target manufacture projects to mass production at the quality desired for
7371 direct drive and within the cost required for power production.
7372
7373 3f. KrF direct drive laser IFE is estimated to be cost-competitive with other IFE
7374 or MFE plant designs.
7375
7376 Note: NIF can also be upgraded to operate at 4ω in the deep UV if such operation is
7377 necessary for testing LPI at the deep UV vs 351nm.
7378
7379 Heavy-Ion IFE Events-Based Roadmap to DEMO (TA-2)
7380
7381 There are several technical approaches to heavy-ion inertial fusion. Each approach
7382 uses a particular kind of accelerator, a particular kind of target, and a particular kind
7383 of chamber. The two principal types of accelerators are radio-frequency (RF)
7384 accelerators and induction linear accelerators (linacs). Unlike laser fusion, there is
7385 nearly a continuum of targets ranging from targets that are fully directly driven to
7386 targets that are indirectly driven. Ultimately, the program must determine the optimal
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7387 point in this continuum but, in this section, we will simply distinguish between direct
7388 drive and indirect drive. As is the case for lasers, the target ignition modes include
7389 hot-spot ignition, shock ignition, and fast ignition. Heavy-ion fusion appears to be
7390 compatible with several types of chambers, but most power plant studies have
7391 adopted chambers with thick liquid walls to minimize radiation-damage materials
7392 issues.
7393
7394 In order to make progress on limited funds there has, for many years, been an
7395 informal agreement that the United States would pursue induction linacs while the
7396 foreign programs would pursue RF accelerators. In the near-term it is not necessary
7397 to choose between direct drive and indirect drive. The accelerator requirements for
7398 the two cases are similar. The accelerator requirements for fast ignition are quite
7399 different. Fast ignition targets require high kinetic energy ions compared to other
7400 types of targets. The large RF heavy ion accelerators in Germany and Russia are
7401 designed to produce high kinetic energies. Fast ignition is an important part of some
7402 of these foreign programs. Although large future machines such as the Facility for
7403 Antiproton and Ion Research (FAIR) in Germany may be able to do some preliminary
7404 experiments on fast ignition, they will likely fall short of the required ignition
7405 temperature by more than two orders of magnitude. Consequently it appears difficult
7406 to validate ion fast ignition physics. In the remainder of this section we will consider
7407 only the US program—induction linacs and direct or indirect drive.
7408
7409 Pre-conditions for FTF or DEMO.
7410
7411 Much of the target information for heavy-ion fusion is based on computer simulations
7412 using the codes that are also used for laser and pulsed power fusion. There is also
7413 limited experimental information on ion-driven fusion, including heavy-ion energy
7414 deposition experiments in cold and laser-heated matter and light-ion-beam-driven
7415 hohlraum data up to about 60 eV 1,2. For information on inertial confinement fusion
7416 physics, it is currently necessary to rely on classified data and the laser fusion
7417 programs, particularly the NIF program. Given this situation, we now turn to the pre-
7418 conditions needed for a heavy-ion fusion FTF or DEMO:
7419
7420 1a. Laboratory-scale ignition on NIF or elsewhere is necessary. These ignition
7421 experiments must be convincingly connected, using state-of-the-art computer
7422 simulations and existing ion target data, to the achievement of high gain (G > 30) ion-
7423 driven targets. Since the fuel capsules for indirectly driven ion-beam fusion are
7424 similar or identical to those for indirectly driven laser fusion, and since ions have
7425 driven hohlraums to approximately 60 eV, it is much easier to make a convincing
7426 connection for indirect drive than for direct drive.
1
Intense Ion Beams For Inertial Confinement Fusion, Mehlhorn TA, IEEE Transactions On
Plasma Science , V. 25(#6) pp. 1336-1356 Dec 1997
2
M. S. Derzon, G. A. Chandler, R. J. Dukart, D. J. Johnson, R. J.Leeper, M. K. Matzen, E. J.
McGuire, T. A. Mehlhorn, A. R. Moats, R. E. Olson, and C. L. Ruiz, ³Li-beam-heated
hohlraum experiments at particle-beam-fusion-accelerator-II,² Phys. Rev. Lett., vol. 76, pp.
435438, 1996
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7427
7428 1b. In addition to the current uncertainties in target physics, there are also
7429 uncertainties in accelerator physics, at least for the high current beams needed for
7430 fusion. To address these uncertainties it is necessary to show that NDCX-II, the ion
7431 induction linac currently coming on line at the Lawrence Berkeley National
7432 Laboratory, meets its designs goals and that its performance matches theory and
7433 simulation. A result of these experiments should be a validation of the accelerator
7434 and beam physics codes at increasing intensity.
7435
7436 1c. Transport of driver-scale beam charge density in magnetic quadrupoles without
7437 serious degradation of beam quality (ability to be focused) must be demonstrated and
7438 provide further validation for beam transport codes. This can be done by restarting
7439 and upgrading the existing HCX accelerator at LBNL.
7440
7441 1d. Ion sources, magnetic quadrupole arrays, high-gradient insulators, high-voltage
7442 pulsers (similar to those needed for the KrF and PP approaches to IFE), and magnetic
7443 materials for induction cores must be further developed to demonstrate adequate cost,
7444 reliability, durability, voltage gradient, and efficiency. These components must be
7445 assembled into induction acceleration units in an IRE. Pulsing these units at 10 Hz
7446 for 3 years will give a total of approximately 109 shots of reliability and durability
7447 testing.
7448
7449 1e. It is necessary to produce a complete design of a final focusing system that
7450 rigorously meets all known requirements associated with beam physics and shielding.
7451 This focusing system must be integrated with a credible chamber design.
7452
7453 1f. The successful completion of items a through e leads to a major decision point,
7454 the decision to proceed with the construction of a 10 kJ to 100 kJ accelerator, the
7455 initial step of an FTF. This accelerator must validate the performance of scaled
7456 hohlraums and/or adequate hydrodynamic stability for directly driven ion targets. If
7457 the estimated cost of this facility is greater than a few hundred million dollars, item d
7458 has failed to demonstrate adequate cost since the cost of this facility would not
7459 extrapolate to acceptable cost for a full-scale driver.
7460
7461 1g. If the intermediate accelerator described in f successfully validates the target
7462 physics for direct and/or indirect drive, and if credible target fabrication techniques
7463 and a credible chamber have been successfully demonstrated, there is enough
7464 information to make a decision to construct a full-scale accelerator driver. This driver
7465 must demonstrate an efficiency-gain product ≥ 10. At this point, enough information
7466 would be available to proceed to an FTF. To minimize the cost of performing the
7467 demonstration of efficiency and gain, the driver would be built initially without all the
7468 power supplies necessary for high repetition rate. It would be upgraded to drive an
7469 FTF by adding more power supplies.
7470
7471
7472 Pulsed Power IFE Events-Based Roadmap to DEMO (TA-3)
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7473
7474 There are two Technology Applications (TAs) to pulsed power (PP) inertial fusion
7475 energy (IFE) at present. One involves magnetic implosion of magnetized, laser-
7476 preheated fusion fuel on a ~100 nanosecond time scale and goes by the name of
7477 Magnetized Liner Inertial Fusion, or MagLIF. Other unpublished approaches that
7478 would use ~100 ns pulsed power to implode fusion fuel are also under consideration.
7479 The other TA, called Magnetized Target Fusion, or MTF, is related to MagLIF
7480 through the use of pulsed power technology and magnetic implosion as the driver
7481 approach, but is otherwise quite distinct—the implosion time scale is more than 10
7482 times longer, the length scale is more than 10 times larger, the magnetic configuration
7483 is different (MTF seeks to compress a field reversed configuration because of the
7484 longer time scale) and the plasma density is 100−1000 times lower. In a broad IFE
7485 program including PP IFE, there would be one down-select based upon physics and
7486 technology between the shorter and longer pulse PP IFE TAs.
7487
7488 Although the power-plant ideas presented by the proponents of MagLIF and MTF
7489 differ, the challenges are the same: high yield per pulse in a liquid wall chamber at a
7490 repetition rate of order 0.1 HZ, and the chamber must be commercially viable and
7491 long-lived; and delivery of the current to the target must be accomplished reliably
7492 with standoff. Generically, the latter challenge is addressed with Recyclable
7493 Transmission Lines (RTLs), and the chamber is assumed to be a thick liquid wall
7494 chamber that must recover “completely” to its undisturbed state in the ~10 seconds
7495 between pulses.
7496
7497 MagLIF: Pre-conditions for FTF or DEMO.
7498
7499 Up to now, all “data” on MagLIF is from computer simulations. A substantial
7500 systematic experimental campaign is planned each year for 5 years to validate the
7501 computer simulations and to determine if the goal of scientific breakeven can be
7502 achieved on the existing 27 MA Z-machine at Sandia. Scientific breakeven is defined
7503 as fusion energy out (using D-T fuel) equals energy delivered to the fuel.
7504
7505 1a. If scientific breakeven is achieved and predictive validity of the design code(s) is
7506 demonstrated, results should be compared with other existing results. If one is clearly
7507 making more progress than the other, a down-select might be made by the end of the
7508 5-year period based upon code predictions of which will be the most favorable
7509 approach for IFE. Here we must assume that it is unnecessary to take into account
7510 differences in reactor technology to do this down-selection. However, if there are
7511 significant differences, the necessary engineering design tasks should be carried out
7512 during the 5-year period. The conceptual design of a gain > 1 facility should be
7513 developed. If possible, that facility should be designed to be upgradeable to a high
7514 gain facility (FTF) rather than requiring a completely new facility.
7515
7516 1b. If scientific breakeven is achieved but predictive capability is not achieved,
7517 experiments and theoretical research must continue before any decision is made to go
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7518 for an IFE ignition facility. However, NNSA may decide to initiate preparations for a
7519 single-shot ignition and high gain facility depending upon mission requirements.
7520
7521 1c. If scientific breakeven is not achieved and the reasons are not understood,
7522 MagLIF’s place in the broad IFE program should be reconsidered in light of progress
7523 on other TAs.
7524
7525 1d. Pulsed power technology must have favorable long life-time and high efficiency
7526 projections as well as low maintenance and repair cost expectations for MagLIF to go
7527 on to an FTF although a single shot high gain facility may still be of interest to
7528 NNSA.
7529
7530 1e. A conceptual chamber design with life expectancy >107 pulses must exist for the
7531 0.1Hz, 10 GJ yields presently favored by PP IFE proponents or the approach must be
7532 re-optimized at a different rep-rate and yield per pulse; and engineering projections
7533 for use of RTL’s must be favorable and proof of principle experiments for their use in
7534 a pulsed power system must be successful before an FTF design is undertaken.
7535
7536 MTF approach to PP IFE: Preconditions for FTF or DEMO.
7537
7538 Laboratory experiments on the Shiva Star (operating at 4.5 MJ) capacitor bank
7539 deliver up to 12 MA of current to a 10 cm diameter, 30 cm long, 1 mm thick
7540 aluminum (Al) cylinder. Assuming success of integrated experiments in which field
7541 reversed configuration plasmas are injected into the Al cylinder and then imploded,
7542 explosively driven experiments are to follow. Computer simulations are carried out
7543 using the Mach2 MHD code.
7544
7545 2a. The Shiva Star experiments are expected to achieve >1019/cm3, 3-5 keV ~ 1-cm-
7546 diameter plasmas confined in a 300-500 T (peak field) field-reversed plasma
7547 configuration in ~3 years. Success here would lead to the explosively driven
7548 implosion experiments, which could achieve breakeven. The success of the
7549 explosively driven experiments together with demonstrated predictive capability
7550 would make MTF a competitor at the time of PP IFE down select in about 5 years.
7551 Predictive capability must mean that the enhancement of yield due to the presence of
7552 magnetic field in the initial plasma should be understood in detail in spite of poor
7553 diagnostic access.
7554
7555 2b. If scientific breakeven is achieved but predictive capability is not achieved,
7556 experiments and theoretical research must continue before any decision is made to go
7557 for an IFE ignition facility.
7558
7559 2c. If scientific breakeven is not achieved and reasons are not understood, MTF’s
7560 place in the broad IFE program should be reconsidered in light of progress on other
7561 TAs.
7562
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7563 2d. Pulsed power technology must have favorable long life-time and high efficiency
7564 projections as well as low maintenance and repair cost expectations for MTF to go on
7565 to an FTF, although a single shot high gain facility may still be of interest to NNSA.
7566
7567 2e. A conceptual chamber design with life expectancy >107 pulses must exist for the
7568 0.1Hz, 5 GJ yields presently favored by MTF proponents; and engineering
7569 projections for use of RTL’s must be favorable and proof of principle experiments for
7570 their use in a pulsed power system must be successful before an FTF design is
7571 undertaken.
7572
7573
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