ARIES Documents
Utility Advisory Committee Reports
Minutes of the Fifth Meeting (October 13-14, 1994, UC San Diego)
Power Plant Studies Utility Advisory Committee, and EPRI Fusion Working
Group
INTRODUCTION
Dean Robert W. Conn opened the combined Utility Advisory Committee/EPRI Fusion
Working Group Meeting, hosted by UC San Diego, by welcoming all attendees. He
introduced Dr. Robert Iotti of Raytheon Engineers and Constructors, who
recently has been appointed as Administrative Officer to the ITER Joint Central
Team, to review the status of ITER.
ITER UPDATE
Dr. Iotti explained that his first and most important duty was to make sure
that the routine management processes were in place at the Joint Central Team
work sites and are working smoothly. After that, those management processes
that are unique to ITER and the technical issues will be addressed.
Dr. Iotti reviewed the status of ITER. He noted the significant change in
management style that had occurred recently within the ITER Joint Central Team,
towards a more team-oriented style which would better fit the current stage of
the project. He remarked that the previous management appeared to have been
criticized unduly, and that the previous manner of operation was probably
necessary during Protocol 1 since the goal was to make rapid progress towards
defining a conceptual design basis.
Critical topics that will receive much greater attention and input as the
design evolves include safety and remote maintenance. Other critical issues
requiring further design modifications are the magnets, divertor, and first
wall and blanket. It appeared that in the technical areas, not all of the
requirements had been clearly identified or correctly ranked. For instance,
the performance of the device had been the principal driver of the design,
while safety now will assume a much higher priority with remote handling
requirements, rather than solely performance driving the design details to a
greater extent. The designs of several systems are being re-examined to assure
that the selected design approach is appropriate. The items that are being
re-examined include the toroidal field (TF) coils, the choice of poloidal field
(PF) superconducting materials, the coil case design, the addition of another
PF coil, the remote handling aspects of the vacuum vessel, the divertor
armor material, a closer-fitting cryostat, and the tradeoff between plasma
control and reactive power.
The chairman of the joint committees, Steve Rosen, commented on the very high
post-shutdown dose rates within the ITER torus and asked if the predicted value
of 1x106 R/h radiation level at shutdown inside the torus is
correct. Both Dr. Iotti and Dr. Conn affirmed the nominal level is
expected to be 3x106 R/h within 24 h after shutdown, and that
the level would remain high for years. This is due to the choice of stainless
steel as the vessel structural material. Vanadium and silicon carbide (SiC)
composites would significantly reduce the level of the post-shutdown radiation
and its half life, but would not eliminate the need for remote handling
operation inside the torus. These low-activation materials, vanadium and SiC
composites, are not being used because there is insufficient engineering data
available to define their characteristics in the fusion environment. Large
scale manufacturing and fabrication techniques still must be developed, and
engineering codes (similar to ASME codes) are still to be developed. Thus the
structural material of the vessel must be stainless steel or the project would
have to be delayed until sufficient data becomes available.
Historically, it has taken decades to develop an acceptable database and
sufficient fabrication experience for the design of a Demo power plant. The
ensuing discussion resulted in general agreement that advanced materials will
be needed in order to make a tokamak attractive to a utility. ITER must give
the utilities the confidence that it will help support the rationale for
Demo.
Bob Conn explained that the physics goals will be demonstrated in the Basic
Performance Phase (BPP) of ITER. In the following phase, called the Extended
Performance Phase (EPP), a number of advanced breeding blanket modules will be
tested in ITER. Prior to this, a neutron-source materials test facility is
planned to provide sufficient test results for candidate materials to enable
confident design, fabrication, and operation of full-sized modules in the ITER
EPP phase. It was indicated that the ITER EPP phase could "qualify" first
walls, blankets, and divertors, though a final conclusion on this cannot yet be
made.
Given the current pace of effort on advanced materials testing and the tight
schedule for Demo, there appeared to be some weaknesses in the development
plan. For example, there was no indication that the materials test results
would flow into ITER before they were used in Demo design. Some concern
expressed by the Advisory Committee prompted the scheduling of presentations on
the topic of develoment pathways during the next meeting.
Another conclusion was that, unless there is an early and strong fusion
materials development program together with the construction of an appropriate
test facility or facilities, the currently planned Demo will not be viewed as a
true Demo by the utilities. It appears clear that ITER alone does not allow
proceeding directly to Demo. Dean Conn and Dr. Iotti explained that the
current DOE and ITER strategy does call for an advanced materials test
facility. The use of an advanced materials test facility, in combination with
limited component testing during the "extended performance phase" of ITER,
could still lead to the fusion Demo after ITER.
Dr. Iotti discussed the on-going regulatory and licensing efforts for ITER.
Several committees and working groups are trying to define approaches and
frameworks to streamline the process, while assuming the promise of a safe and
clean energy source. It is clear that ITER requirements will be more severe
than those envisioned for Demo and the follow-on commercial fusion power
plants. It is essential that ITER not set overly restrictive licensing and
regulatory precedents for subsequent fusion generating plants.
UPDATE FROM DOE
Al Opdenaker, Office of Fusion Energy, provided an overview of the U.S. fusion
program. He reviewed the current budget for OFE and outlined some of the
recent Congressional legislation which may impact the future direction of the
U.S. fusion program. ITER siting issues were raised, and the question of U.S.
interest (and commitment) was discussed in the event that ITER is sited
elsewhere. Specifically, the Committee asked if the U.S. wants ITER to be
sited in the U.S. Al Opdenaker responded that no decision has been made. Dean
Conn explained that acquiring the site for ITER may not be quite as desirable
as previously thought. An alternate premise that is now viable is that, with
the advent of higher quality communications, the experiments in ITER could be
conducted from remote sites. It is entirely possible that there will be fewer
scientists at the actual site than first thought and more scientists at
distributed sites. This would modify the economic assumptions that had been
considered so far as well as the anticipated technical benefits arising from
the economic contributions.
Various advisory and review committees have been formed and are expected to
assess the U.S. fusion program during the next few months. Of particular note
is the reconstitution of the Fusion Energy Advisory Committee (FEAC) following
an extended dormancy. Dean Conn will again assume the chairmanship. Steve
Rosen will be a member. The majority of the membership will be persons from
technical fields other than fusion and from industry. Previously the
membership consisted primarily of persons from within the fusion community.
ITER ECONOMIC STUDY
Ken Wilson reported the results of an ITER Economic Study on ITER siting that
had been undertaken by Argonne National Laboratory with the assistance of
external economic experts. The study addressed the national economic benefits
to the U.S., and the benefits to the local community, of siting the ITER within
the U.S. or elsewhere. The construction period was assumed to be 8 years at a
total cost of $10B, followed by an operating period of 18 years at a total cost
of $8.6B, with a further $1B being required for decommissioning, for a total
lifetime cost of $19.6B. An analysis based upon these assumptions concluded
that the host party would incur 40% of the total cost. Of the remaining 60% of
the cost, 42% would be spent by non-host parties within their local economies,
and 18% would be spent by non-host parties at the host site. There would be a
very small benefit to the U.S. economy overall through siting ITER in the U.S.,
and a small negative impact if ITER were sited elsewhere. On the other hand,
the benefits to the local community in which ITER is sited will be enormous.
Peak host employment by ITER itself is estimated at 3,000 during construction
(with 11,000 total additional jobs being generated in the local area) and at
900 during operation (with 4,000 total additional jobs in the local area). The
study did not, however, take into account any spin-offs that might arise from
ITER, nor did it consider what alternative benefits might arise if the money
was not spent on ITER but was spent on some other major project instead.
A new paradigm for international participation in ITER that had been suggested
by Dean Conn, in which many of the scientists and their support staff would
remain in their home country and interact effectively through advanced
telecommunications methods, would tend to reduce the incentive to host ITER.
FIRST-OF-A-KIND FACILITIES
Larry Papay of Bechtel discussed his experiences with first-of-a-kind energy
generation facilities and surveyed first-of-a-kind startup problems in several
related technologies involving facilities such as Clinch River, Cool Water,
Solar Two, and Superconducting Magnetic Energy Storage (SMES). Approaches to
forming consortia to build and operate a Demo were discussed. It was
emphasized that DOE must convince the utilities and industries to participate
early in the project to ensure that their own specific needs are satisfied and
competent engineering firms are available to build the fusion Demo. Having the
right project scope, plant size, and adequate funding are critical.
Dr. Papay thought that industry would be the likely project leaders, and that
government, industry and utilities would fund the project through some form of
cost sharing. Ideas for cost indemnification were discussed, based upon the
assumption that utilities would only participate in Demo if there was a clear
financial incentive to do so. For example, if the cost of Demo was 1.2 times
the prevailing cost of electricty (COE), but the U.S. Government subsidized 50%
of the cost, a utility might be willing to take the risk if it felt there was a
reasonable probability of a positive financial return on its investment.
Additional (financial) participation from the private sector, an industrial
consortium say, might be expected if the investment was seen to place the
consortium in a strong position to win future orders. Such a consortium might
comprise a number of industrial vendors, A&Es, and utilities. Governmental
assistance could take the form of direct funding, funding guarantees,
guaranteed (or forgiven) loans, or favorable tax incentives. The possibility
of a single vendor stepping forward and assuming a major portion of the $4B of
industrial funding that would be required to construct Demo was discussed.
Although a single vendor would be preferred, the consensus was that the
financial risk was too large for any one company to assume. Betting one's
company on the success of Demo would present too much of a risk based upon
today's knowledge.
The preferred size of Demo was discussed. Although there was a previous
successful program in which a demonstration unit rated at 10% of the required
commercial size was constructed and operated, a fusion generator this small was
not thought to be realistic for subsequent scaling to full size with low risk.
The feasible size for a demonstration fusion power plant was thought to lie
within the range of 30% to 80% of the required size of the commercial system.
This scenario balances a lower capital cost and a less profitable Demo against
a higher capital cost, a lower scalability risk, and a more profitable Demo.
Other unknowns involve the nature of the future energy market, the public
perception of energy options, and Federal legislation and regulations that will
change relationships within the energy community.
REMOTE HANDLING TECHNOLOGIES
Tom Burgess reviewed the remote handling technologies associated with TFTR and
JET and those being planned for ITER. Some of the manipulator systems in use
are extremely sophisticated, having as many as 28 degrees of freedom. In
general, these systems are extremely complex and often require long down-times
for replacement of even very small components. Existing maintenance schemes
clearly have been designed "a posteriori", much later than the design of the
basic tokamak itself.
Dr. Burgess described the evolving ITER Remote Handling requirements and
systems. Radiation doses of 3x106 R/h are expected as a remote
handling environment in the torus interior. Some ITER components (for example
the first wall, blanket, and divertor modules) are scheduled for regular
replacement. Other components (for example the cryostat and magnets) should
not require replacement during the entire life of the plant. In-torus remote
handling is to be accomplished at atmospheric pressure. Dr. Burgess described
some of the maintenance steps for ITER. All ITER components are being designed
to be removed and replaced remotely. For example, the divertor segment
replacement scheme requires the removal of up to four neighboring segments.
Most of the maintenance operations will be performed through small openings,
and require the use of either cantilevered arms or rail systems.
Steve Rosen remarked that remote handling is one of the most serious concerns
of the committee. Dr. Wilson reminded the audience that Dr. Iotti had
acknowledged the lack of consideration of remote handling in the earlier
design, and had expressed the firm intent to raise this issue to the forefront.
Dr. Najmabadi stated that commercial power plant remote handling systems would
be very different from these currently being designed for ITER, and explained a
potential maintenance scheme that had been developed during the ARIES study.
By taking advantage of the smaller plasma, fewer coils, and a novel cryostat
design, it was possible to place the TF coils far enough away from the
in-vessel components such that simple horizontal removal of entire segments
became possible on rails. In this instance, a stand-by segment would be
inserted quickly, and problems of the removed segment would be repaired away
from the fusion device.
Ken Wilson affirmed that, although stainless steel will be used as the
first-wall and blanket structural material in the Basic Performance Phase of
ITER, test modules of vanadium and liquid lithium will be available for
evaluation in the Engineering Performance Phase. This emphasized the need to
develop an advanced materials data base for the fusion environment with
adequate fluence to predict the end-of-life performance. Additionally, there
will be a need to validate component performance prior to the ITER Extended
Performance Phase, perhaps through small scale testing during the ITER Basic
Performance Phase or via testing in a separate volume neutron source.
REAL AND REACTIVE POWER REQUIREMENTS
Charles Neumeyer of Raytheon Engineers and Constructors presented the
current ITER active and reactive power requirements. The cycling poloidal
field coils require 3,500 MVA for operation. The final power requirements are
being developed to minimize the impact on the local utility that supplies the
power. High power demands for short time periods may pull down grid voltage
and frequency to unacceptable levels unless some modifications to the ITER
requirements are made.
TFTR: HISTORY AND RECENT RESULTS
Dr. Dale Meade of Princeton Plasma Physics Laboratory discussed the history of
TFTR and the most recent program achievements including results of DT
operation, neutron measurements and alpha physics. The goals set for TFTR in
1976 have been met and, in several areas, exceeded. An important observation
was confirmation that confinement in DT plasmas is better than that in pure
deuterium due to an expected, but poorly understood, mass effect. There will
now be an additional year of testing to explore D-T confinement enhancement and
higher power operating regimes.
Steve Rosen felt that the term "helium ash" should be avoided: the fusion
community has adopted an unfortunate nomenclature since the word "ash" gives
rise to negative connotations. In fact, helium is a naturally-occurring,
non-radioactive benign gas that we use in the Goodyear blimp and in balloons we
give to children as toys.
TFTR operates with limiters which are made of carbon fiber composite (CFC)
tiles aligned on the inboard side of the plasma. Some discussion and
explanation of the nature of limiter operation, and of the anticipated greater
efficiency that would arise from the use of a divertor, ensued. Magnetic
confinement of the plasma is opposed by pressure-driven diffusion. As the
plasma expands, first it brushes up against the tiles that comprise the
limiter. This evoked a discussion of the alignment requirements for these
tiles. In TFTR, the alignment tolerance requirement is ~1.5 mm with respect to
the magnetic field, but it is the nature of CFC's that misalignments tend to be
self-correcting.
One recent improvement in TFTR has been the installation of a cryogenic
distillation plant for tritium processing, designed and fabricated by Canadian
Fusion Fuels Technology Project. The plant has four distillation columns that
have a very low tritium inventory. The system works very efficiently despite
the fact that there is only a 1 K difference in boiling points between
hydrogen, deuterium, and tritium.
Some impressive neutron measurements have been made at TFTR. Neutron yields
agree with theoretical calculations, accounting for beam-beam, beam-plasma, and
plasma-plasma reactions.
Alpha-particle measurements using charge-exchange processes were described.
One of the more serious concerns with alpha reaction product generation is TAE
(toroidal Alfvén eigenmode) instabilities stimulated by high-energy
alphas. The phenomenon was observed in a single, high-power test shot.
Further investigation is needed to reproduce and verify its existence and,
should this be the case, to explore the use of density profiles to suppress and
control it.
A discussion of the regulatory process for TFTR was stimulated by Jack Kaslow.
TFTR experienced a difficult approval procedure for a DOE fusion facility, but
public acceptance of the facility has been excellent. TFTR used DOE
regulations, rather than those of the NRC, in much the same way that Rocky
Flats and Savannah River had. This has proved to be a tortuous, expensive, and
time-consuming process. Approximately $40M was spent in unforeseen ES&H
retrofits.
An overview of the plan for the U.S. fusion program plan was presented on a
single viewgraph. ITER was shown as the "integrator" machine, taking input
from TPX and from a Materials Test Facility which has not yet been approved,
and leading the way to a fusion Demo. The committee felt that the absence of a
materials test facility was a "show-stopper", since the technologies that will
be used for ITER will not be attractive to Demo and will certainly not attract
funding from the private sector. It was agreed that more attention would be
given at a future meeting to the testing facilities that would prepare the
program to move into technologies relevant to Demo and to a commercial
generating plant. Mark Tillack was tasked to present more detailed information
on this subject at the next meeting. The committee viewed this materials
research and component development as being critical to the commercial success
of the fusion program.
DEMO MISSION AND OBJECTIVES
Dean Robert Conn presented some initial results from the Starlight Demo reactor
study, focusing on the mission and goals of the Demo. In order for fusion to
be attractive, it must provide safety advantages over fission (since it is
unlikely to be less expensive) and cost advantages over solar (since it is
unlikely to be safer).
The question of scaling from Demo to a commercial power plant was discussed.
No obvious answer emerged from the discussion since the ability to scale
depends upon the characteristics of the technology. However, a Demo in the
range of 33% to 80% of the size of the follow-on commercial machine was thought
to be acceptable. On the other hand, a Demo at one tenth of full-scale was
thought not to be acceptable.
The trade-off between Demo cost of electricity and the total cost of the device
was discussed. The point was made that a smaller machine, constructed at lower
cost, may not be capable of producing electricity economically. Hence, even if
the U.S. Government were to pay half the cost of the plant, the utilities would
not be interested in it if they had to pay a per-kW-hr penalty. Steve Rosen
emphasized that without visionaries, fusion would be a "hard sell". The nature
of the present economic infrastructure tends to discourage visionaries; hence,
fusion simply must demonstrate a cost advantage.
Waste disposal and the decommissioning of Demo were discussed. It was
recommended that Demo should adopt methods of waste disposal which already
exist, and not propose new methods which could lead to long drawn out debates.
Although a fusion plant should be priced for, say, a 30-year economic life, the
licensing of a fusion plant should be for an indefinite period and should not
stipulate an expiration date. Since all of the life-limiting in-vessel
components can be replaced, artificial restrictions should not be placed on the
life of the plant.
DISCUSSION OF MINUTES OF THE PREVIOUS MEETING
A modification to the draft minutes of the previous meeting was discussed at
length. This included the cost projections for Demo and concepts for cost
sharing and consortia establishment. Aside from the modification, the minutes
were approved and Terry Davies was asked to distribute the final approved
minutes. In future meetings, the minutes of the previous meeting will be
distributed to the committee for approval prior to formal distribution.
DATE OF NEXT MEETING
The committee agreed to hold the next meeting at UC San Diego on February
16-17, 1995. Topics to be included are:
- The Safety, Siting and Regulatory Aspects of ITER and DEMO (e.g., Drs.
Iotti, Baker and Longhurst),
- Mission and Goals of DEMO (Dean Conn and Dr. Najmabadi),
- DEMO Testing Needs and Development Pathways (Dr. Tillack)
Appendix I: Meeting Attendees
Tom Burgess ORNL 615-574-7153
Bob Conn UC San Diego 619-534-6237
Terry Davies UCSD 619-534-9830
William Dove OFE/DOE 301-903-4598
Sheng Guangzhao SWIP 619-455-4258
Robert Iotti Raytheon/ITER
Jack Kaslow EPRI 603-894-6345
John McCann Conn Edison 914-734-5566
Dale Meade PPPL
Ronald Miller UCLA/UC San Diego 619-534-7842
Bill Muston Texas Utilities 214-812-8407
Farrokh Najmabadi UC San Diego 619-534-7869
Charles Neumeyer Raytheon 609-243-2159
Albert Opdenaker OFE/DOE
Steve Rosen HL&P 512-972-7138
Glenn T. Sager General Atomics 619-455-2543
Dai-Kai Sze ANL 208-252-4838
Mark Tillack UCSD 619-534-7897
Les Waganer McDonnell Douglas Aerospace 314-233-8617
Ken Wilson Sandia 510-294-2497
Clement Wong General Atomics 619-455-4258
Appendix II: Meeting Agenda
9:30 AM - OCTOBER 13, 1994
1. INTRODUCTION AND WELCOME ROBERT CONN
2. ITER UPDATE ROBERT IOTTI
3. DOE UPDATE AL OPDENAKER
4. ITER ECONOMIC STUDY KEN WILSON
LUNCH 12:00 NOON-1:00 PM
5. "FIRST OF A KIND" START UP EXPERIENCES LARRY PAPAY
6. ITER REMOTE MAINTENANCE TECHNIQUES TOM BURGESS AND
JOE HERNDON - ORNL
7. ITER REAL AND REACTIVE POWER REQUIREMENTS CHARLES NEUMEYER
ADJOURN - 4:00 PM
8:30 AM - OCTOBER 14, 1994
8. D-T EXPERIMENTS IN TFTR DALE MEADE
9. DEMO MISSION AND GOALS ROBERT CONN
10. SUMMARY & SELECTION OF ITEMS FOR NEXT MEETING ROBERT CONN & STEVE ROSEN
11. DATE AND LOCATION OF NEXT MEETING
ADJOURN - NOON
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