a small high field torus for changing...

SPARC Underground PSFC IAP, Jan 14th 2016, SPARC mission

SPARCSoonest/Smallest Private-Funded Affordable Robust Compact

A small high field torus for changing climates

B. Mumgaard, Z. Hartwig, B. Sorbom, D. Brunner

Thoughts on new technology, private funding, and modern innovation techniques to accelerate fusion energy


Viking, 1975, $4B, 15+yr program

• Viking 1&2 landed on Mars• Opened an entire scientific enterprise• Next steps were obviously eminent!

We’ll start with a different area of science/technology: NASA science prior to the 2000’s

1

Carl

2015 dollars


Viking, 1975, $4B, 15+yr program

• Viking 1&2 landed on Mars• Opened an entire scientific enterprise• Next steps were obviously eminent!

• Steps widely agreed upon, endorsed• But no agreement on the order to do it• So do it all or nothing!

It looked like we were going to understand Mars!We just needed to take the next big step.

1

Carl


Voyager, 1977$1B, on budget

on time

Galileo, 1986$3B, 3x cost overrun

10yrs to build, 7 years behind

Hubble, 1993$3B, 6x cost overrun


Mars observer, 1992 $2B, 2x cost overrun

8yrs to build, 4yrs behind

Cassini/CRAF, 1997, $5B, 2x cost overrun


Meanwhile, others at NASA were doing great, but very hard to wrangle missions.

2

2015 dollars



on time









Meanwhile, others at NASA were doing great, but very hard to wrangle missions.

2

They were technically and scientifically awesome with good ideas and great people behind them.

But when they went over budget and fell behind schedule they cannibalized other projects.

This was, naturally, upsetting to everybody on all sides of the issue.

Many studies have been performed to figure out why there were so many problems…

2015 dollars


Meanwhile, others at NASA were doing great, but very hard to wrangle things.


on time







Cassini, 1997, $5B, 2x cost overrun


“The more money that's involved, the less risk people want to

take. The less risk people want to take, the more they put into their

designs, to make sure their subsystem is super-reliable. The more

things they put in, the more expensive the project gets. The more

expensive it gets, the more instruments the scientists want to add,

because the cost is getting so high that they're afraid there won't be

another opportunity later on- they figure this is the last train out of

town. So little by little, the spacecraft becomes gilded. And you

have these bad dreams about a spacecraft so bulky and so heavy it

won't get off the ground- never mind the overblown cost.”

“That boils down to the higher the cost, the more you want to

protect your investment, so the more money you put into lowering

your risk. It becomes a vicious cycle.”

… the best synthesis came from someone who was there, speaking at the time it was happening:

- Rob Manning, Chief spacecraft engineer, JPL

[Pathfinder, Muirhead]

3



on time









"Gone ... is another chunk of NASA's eroding

reputation for technical brilliance“ –TIME

Then awful things happened. And science, government treasure, people’s life’s work, and NASA’s reputation were impacted.

4


This sucked. Hard. For everybody.


on time









"Gone ... is another chunk of NASA's eroding

reputation for technical brilliance“ –TIME

In 1993 NASA, Congress and The President agree:

NASA is DONE doing multi-billion dollar science missions.

The budgets will be small, if you go over budget it WILL be canceled.

“One failure away from extinction.”

4

NASA and science become a punchline…


Switching over to fusion:We had a good thing going with tokamaks... and then stalled out

Increase in DT fusion power over the first 2 days of D-T

operation on TFTR

TFTR, 1982, $0.5B, 6yrs to build

• In the 1970’s-1990’s tokamaks had drastically increasing demonstrated fusion performance

• TFTR and JET showed >10MW fusion power• Next steps were obviously eminent!

JET, 1983, $0.5B, 5yrs to build &

5



Increase in DT fusion power over the first 2 days of

operation on TFTR

TFTR, 1982, $0.5B, 6yrs to build

• In the 1970’s-1990’s tokamaks had drastically increasing demonstrated fusion performance

• TFTR and JET showed >10MW fusion power• Next steps were obviously eminent!

• Steps widely agreed upon, endorsed• But no agreement on the order to do it• So do it all or nothing!

JET, 1983, $0.5B, 5yrs to build &

5


2030s

1980s

1970s

1990s

Power plantConditions


ITER$25-50B, 5-10x cost overrun

>20yrs to build, >10 years behind

• Widespread agreement that the process, not the people, is to blame for the problems

• Now under constant review about how/whether to proceed

• Community’s future and people’s life’s work hang in the balance

• Up to the politicians to decide

6


SPARC: A small tokamak for changing climates

4 changing climates outside of fusion….

• How innovation is done has changed

• Private-funding is changing scientific R&D

• The Earth’s climate, and the response, is changing

• HTS changes the pathway to a tokamak fusion reactor

… set the stage for SPARC…

• A tokamak with a targeted mission

• With a conservative plasma physics basis

• A heat exhaust challenge with solutions that might work

• Mitigation of radiation in the magnets

… which we think could change fusion’s climate.



The 4 changing climates….


• Private-funding is changing scientific R&D



… set the stage for SPARC



• A heat exhaust challenge with solution scoping


… which we think might change fusion’s climate.

Back to that Mars community who now had no way to do what they wanted to do…


Something really interesting happened:A small group at JPL did things drastically differently

7

Mars Pathfinder, 1995$0.15B, on budget

on time (34mos) 100% successful

They found a little pot of money, not much..

.. quickly built a small, focused spacecraft..

.. taking risks only small budgets allow..

.. launched it to the red planet...

…using a novel combination of new technology, proven engineering and hard-won experience.

…bounced to a landing...

Unfolded a lander... …booted up, phoned home...

...took spectacular pictures…

…did 3 months of cutting-edge science...

…drove rover “Sojourner” to intriguing rocks...


• For 1/20th the price and for 1/3rd the development time of Viking, a team of ~100 people were able to land, drive a rover, and do compelling science on Mars

• This mission was considered to be “impossible”, “foolish” and “career suicide”

• It was an incredibly compelling story• Front page of every newspaper• Broke internet records• Inspired a generation of scientists and

engineers• Spawned a continuing legacy

(Spoiler!!) And helped bring Matt Damon home so he could give MIT’s

2016 commencement address.(How do you like them apples?)

….and the world turned and watched in awe.

8


Sojourner1995: ~$150M

Spirit/Opportunity2003 : ~$820M Curiosity

2012 : ~$2.4B

Success breeds success Mars 2020 Rover, caching samples for return

The successful mission came to define the era of“Better, Faster, Cheaper”

• The Mars budget grew from $50M/yr to $800M/yr

• A rapid series of missions were launched, each bootstrapping on the success of the others

• The program now attracts the best and brightest

• Now a multibillion dollar global endeavor making rapid progress and engaging the pubic

And it quintessentially changed the way NASA does robotic space while paving the way for a robust Mars program.

9

2015: Flowing water!

Looks like fun

Everybody working together


Sojourner1995: ~$150M

Spirit/Opportunity2003 : ~$820M Curiosity

2012 : ~$2.4B

Success breeds success Mars 2020 Rover, caching samples for return

The successful mission came to define“Better, Faster, Cheaper”

• The Mars budget grew from $50M/yr to $800M/yr

• A series of rapid missions were launched, each bootstrapping on the success of the others

• The program attracts the best and brightest

• Now a multibillion dollar global endeavor making rapid progress and engaging the pubic

And it quintessentially changed the way NASA does robotic space while paving the way for a robust Mars program.

9

Flowing water!

Everybody working together

After 20 years of little progress when budgets were loose

(1975-1995)…

…they made remarkable progress in 20 years when budgets were

tight (1995-2015)…

…initiated by the right approach, at the right time, in the right

place, solving the right problems, to change the outlook.


Imagine if we could do something like this in fusion.


operation on TFTR

10*SPARC foreshadowing


Imagine if we could do something like this in fusion.In 20 years it sure would be nice to say:


operation on TFTR

• The fusion funding grew to from <$250M/yr to >$2,500M/yr and the sources diversified

• Many targeted devices were built, retiring risks

• The program now attracts the best and brightest

• Now a multibillion dollar global endeavor making rapid progress and engaging the public

• Building an industry to help alleviate climate change

“What is fusion energy’s version of Pathfinder?”

10


Pathfinder, without knowing it at the time, was executing what we now call the lean innovation cycle.

11

1. Landing on Mars and roving (as opposed to orbiting) will provide compelling technical demonstration and

science, paving the way for further exploration

2. This could be done on a low budget using innovation and

targeted risk taking.

3. Largest risk and cost is entry, descent, landing. Use innovations:

Direct entry from deepspace, and use airbags to “just get it down”.

4. Test things extensively instead of adding redundancy.

Use spare parts where possible. Engage the public early and

often.

5. Build the smallest, simplest system possible. Stick to the budget and schedule, prevent scope

creep.

6. Launch it and land as the world watches it work.

7. The science community, the public, and NASA are

excited. Now have a proven way to land and do science.

Launch more rovers, landers, orbiters. Each time repeating

this cycle, building on past success. Each time retiring risks, raising excitement.

This is different from making a big list of feature, building a single large thing, and seeing if your assumptions were correct at the very end. (called waterfall development)


Keys:

• Cycle as fast as possible

• Always build the simplest, fastest,

cheapest thing customer will pay for

• Focus on the most valuable feature set,

the sponsor helps you figure this out

• Learn about your technology and also

about the customer at every cycle

• Involve user/customer/sponsors early

• Cycling fast allows you to take risks by

quickly pivoting away from failure

• Success can be quickly measured and

rewarded

• Eventually move from market to

market, avoiding the valley of death

12

Goes by many names: virtuous feedback cycle/lean startup/customer development/agile development/disruptive/move-fast-break things.


This is now the standard way to do technology development

Hardware, software, big company, small company…


13

1. A major barrier to commercial space is

nobody thinks a private company can develop and

launch a rocket

2. Success with a small rocket will lead to money for bigger rockets.

3. Largest risk is system integration, can be proven in

small rocket.

4. Build a company to design, prove and integrate totally

new engine and rocket

5. Make the (tiny) Falcon 1

6. Launch it. First 3 fail, 4th a success. Leads to large investment surge to begin developing larger Falcon 9 rocket.

7. Keep launching ever larger rockets, while

cycling to learn. Eventually get to Mars.




13





13

Number Title

6.933 Entrepreneurship in Engineering: The Founder's Journey

15.371 Innovation Teams

15.390A New Enterprises

15.232 Business Model Innovation: Global Health in Frontier Markets

15.615 Basic Business Law for the Entrepreneur and Manager

2.009 The Product Engineering Process

2.75 Medical Device Design

15.375 Development Ventures

15.136 Principles and Practice of Drug Development

15.128 Neurotechnology Ventures

15.366 Energy Ventures

15.367 Healthcare Ventures

15.933 Strategic Opportunities in Energy

2.723 Engineering Innovation and Design

15.36 Introduction to Technological Entrepreneurship

15.364 Regional Entrepreneurship Acceleration Lab

15.369 Seminar in Corporate Entrepreneurship

15.378 Building an Entrepreneurial Venture: Advanced Tools and Techniques

15.389A Global Entrepreneurship Lab

15.395A Entrepreneurship Without Borders

15.399 Entrepreneurship Lab

MIT courses this Fall that teach a variation of this



• Involve user/customer/funders early

• Success can be quickly measured and

rewarded

• Can quickly pivot away from failure

• Eventually move from market to

market, avoiding the valley of death

This is what the private fusion companies are doing

Except they are doing it with concepts with physics way behind the “standard” tokamak…. Why aren’t we doing this?

$>100M?$>100M?

$>10M????$5-10M

14






• Private-funding is changing scientific R&D funding









Private money is picking up some slack in federal funding.

• Private individuals, philanthropy, and industry are starting to fund science and

early-stage technology R&D which was once exclusively federal

• There are more billionaires than tough impactful problems

• There is much concern about this!

15


Private money is picking up some slack in federal funding.- For the certain type of projects.

Neuroscience: Allen Institute for Brain Science, $0.5B

Oceanography: Schmidt Ocean Institute, $0.2B

Space launch: SpaceX, Orbital Sciences, Virgin Galactic, $1.1B/yr

Astronomy: Thirty Meter Telescope, $1.4BGMT, $0.7B

Ecstatic astronomer

Astrophysics: Kavli Institutes, $0.1B

Human Genome Project: Celera, $0.3B

Nuclear Power:Terrapower

16*SPARC foreshadowing


Neuroscience: Allen Institute for Brain Science, $0.5B

Oceanography: Schmidt Ocean Institute, $0.2B

Space: $1.1B/yr

Astronomy: Thirty Meter Telescope, $1.4B

Ecstatic astronomer

Astrophysics: Kavli Institutes, $0.1B

Human Genome Project: Celera, $0.3B

Private funding for large science and technology is growing, supplementing

what used to only be federal areas.

But it isn’t a panacea.$1M- easy, $10M-maybe, $100M hard, $1B rare, $10B impossible

But you’ve got to find a way to bootstrap from low amounts, these projects did.

And it has differences from the way fusion is used to operating.

16

Private money is picking up some slack in federal funding.- For the certain type of projects.


Private funding picks different projects than federal funding.And has different metrics for success.

• Private funders expect projects to operate with fast progress and maximal learning/dollar at each step

• Private funders have many great options! This is cut-throat competition!

• The story must be compelling

• The steps must be doable soon

• Progress must be impactful and demonstrable

Private funded projects:

• Visibility is important

• Outsider approach is a plus

• Performance leads to $ for next cycle

• Someday payback with a product or quantifiable societal impact

Government funded projects:

• Constituency is important

• Consensus-based

• Long term on parallel problems

• Supposed to show steady progress in understanding

17


Some clarifying remarks

What I am NOT saying:

• The way we have worked in the past is inferior or bad

• We should change how we do everything

• We should abandon government funding

• That private science R&D is better than government or vice versa

What I AM saying:

• There are different innovation strategies for different types of problems and constraints

• The lean strategy has proven itself in risk intensive, resource constrained situations

• We should recognize that there are larger forces out there and always have been

• And recognize that we will be buffeted by many of them

• This is a reason to move fast and lean

• Government and Private funding sources are different and complementary

• We should recognize the different opportunities, methodologies, metrics, and

mechanisms that they put forward

• Taking the best from each side is a strong strategy both for single institutions and for

the program as a whole

Here and now is a unique place and time to try to do this with fusion

18


Response to climate change may be getting serious, including from philanthropies, foundations, in addition to investors

• Climate change is increasingly alarming to many people

• Driving industry R&D funding back into clean energy, though slowly

• Driving philanthropy and foundations into clean energy R&D

“The only reason I’m optimistic about

this problem is because of innovation.”

– Bill Gates

“The new model will be a public-private partnership

between governments, research institutions, and

investors. Scientists, engineers, and entrepreneurs can

invent and scale the innovative technologies that will

limit the impact of climate change while providing

affordable and reliable energy to everyone. ”

- Breakthrough Energy Coalition,

$2B fund backed by $240B net worth

• Fusion fits what they are looking for

• Yet fusion, as currently executed, is perceived to be too slow to impact climate change

19


WassercraftHydroHydroworld.com

High Temperature Superconductors (HTS) are very well suited for use in robust, compact, high-field magnets

• HTS has several important characteristics

• It has high current density

• It is tolerant to increased temperature

• It is tolerant to high magnetic field

• Its high strength metal tape construction

20





• It is tolerant to high magnetic field


• It is commercially available, it is good enough

Place your order today, get it in a few weeks ½ km of HTS tape, delivered to PSFC in Sep. prior to being wound into coil


20





• It is tolerance to high magnetic field


• It is commercially available, it is good enough

Place your order today, get it in a few weeks ½ km of HTS tape, delivered to PSFC in Sep.


1. J.P. Friedberg, Plasma Physics and Fusion Energy.

We now have a new qualitatively different tool to produce higher magnetic fields than previously

considered for fusion

[1] J.P. Freidberg, Plasma Physics and Fusion Energy.

26T small bore

non-insulatedHTS solenoid,

SUNAM

7Tintermediate

borenon-insulatedpancake coil at the PSFC

“Magnetic fusion, as its name implies, requires high magnetic fields.”

- J.P. Freidberg1

21


R0

Plasma

Shield/Blanket

Magnets

DivertorB0

Lets use this: Tokamaks use high-magnetic fields to confine the hot plasma long enough to produce fusion power

• Confine the hot plasma• Must be cryogenic superconductors

for a reactor

• Hotter than the sun• D-T reactions produce fusion power

• Helium heats the plasma• High-energy neutrons escape

• Exhaust port for intense plasma heat

𝑄 =𝑃𝑓𝑢𝑠𝑖𝑜𝑛

𝑃𝑒𝑥𝑡𝑒𝑟𝑛𝑎𝑙 ℎ𝑒𝑎𝑡𝑖𝑛𝑔

Fusion Goals• The fusion reaction make much more energy than it consumes• In steady-state economically and reliably

• Converts neutrons into heat• Shields the magnet from neutron damage• Breeds the fusion fuel

22

We’ve never gotten Q > 1


R, B plane.

23


Size (and field to some extent) has implications for how large an organization is needed to execute the plan.

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Mu

lti-

nat

ion

alsc

ale

23


Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Mu

lti-

nat

ion

alsc

ale


23


Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Mu

lti-

nat

ion

alsc

ale


23

Proposed

Proposed

Under construction


LTS super conductors put a limit on the field, closing off some operating space for steady-state devices.

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Inaccessible with Nb3Sn superconductors (LTS)

Mu

lti-

nat

ion

alsc

ale

23


High Q achievable in the upper right of the space made available by the previous generation of superconducting technology.

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Mu

lti-

nat

ion

alsc

ale

23


Q


So reactors (which have to be SC), have to live above 5m and at 5-6T. Everybody knows this.

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Reactor

Mu

lti-

nat

ion

alsc

ale

24


Q


The (old) plan: Go to highest field allowed first, then goes up in size. Minimize the number of steps since they’ll be $$.

Reactor

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale This path made sense using superconductors

if non-superconducting devices were considered side-tracks or dead ends.

ITER-EDA “This field is the highest that is practically achievable in large magnets with available superconducting materials.”[1]

[1] Huguet, M. “The ITER magnet system.” Fusion engineering and design 36.1 (1997): 23-32.

Mu

lti-

nat

ion

alsc

ale

25


Q


But HTS opens up a much larger plane. What are the implications?N

atio

nal

scal

eC

om

pan

y/la

b/

un

iver

sity

sca

le

Reactor

Mu

lti-

nat

ion

alsc

ale

26

Q


ARC becomes attractive as a smaller reactor, but its about the smallest reactor that one could build.

Nat

ion

alsc

ale

Can’t shield for long(nuclear physics)

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Reactor

Mu

lti-

nat

ion

alsc

ale

26

Q


Higher field becomes attractive for smaller reactors, but ARC its about the smallest reactor that one could build.

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Reactor

To scale

Mu

lti-

nat

ion

alsc

ale

26

Q



Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Such a device is still $$ and risky. What is the best path to get there? How does the opened space impact the desired path?

Reactor

To scale

Mu

lti-

nat

ion

alsc

ale

26

Q



Using what we’ve discussed from the previous sections we arrive at the SPARC strategy:

1. Hypothesize high return problems and the appetites of private funding to make fusion

relevant to climate change

2. Identify the space plasma physics and new HTS provides

to solve problems3. Identify physics,

engineering, and funding risks to doing a small mission

4. Converge on a problem/device/funder

combo within constraints

5. Build as simple a device that gets the job

done as soon as possible

7. Retire physics and engineering risks and learn about the attractiveness of fusion 6. Run the device, hit/miss

milestones, show/don’t show the potential

Repeat until fusion is a reality or

disproven.

27

*See Tesla


Using what we know from the previous sections we arrive at the SPARC strategy:

1. Hypothesize high return problems and the appetites of

private funding

2. Identify the space plasma physics and HTS provides to

solve problems3. Identify physics,

engineering, and funding risks







Repeat until fusion is a reality or

disproven.

28

Successfully executing this cycle a few times and proving our hypothesis that fusion is attractive could lead to:

• People will start to take notice of fusion as an important contributor

• Interest will grow, bringing funding to the entire field

• Other people will start other cycles

• Competitors indicate we are on the right track!

• Best to test all paths to the same goal

• Opportunities for industry, universities, startups, governments, international organizations will be created

• Together we will accelerate fusion development

• Nobody should plan to go it alone

• There are plenty of problems to solve, sharing knowledge and technology is the best strategy

A rising tide lifts all boats!


Using ARC as a starting point, hypothesize which problems have the highest return on investment?

ARC, MITproposed reactor

9.2 T, 500MW, Q=10

• ARC was a good start, but it was too expensive and too integrated for SPARC strategy

• It was targeted at the electricity generating industry, looks good there

• We can’t just scale it down

• Need to descope

How do we factor all this?Need a small enough, impactful enough, near-term enough set

29




9.2 T, 500MW, Q=10

• We need to at least have a good plan for all of them

• Some can be done offline in parallel or by others

• Some require a pilot plant


30




9.2 T, 500MW, Q=10

• Required in a long pulse integrated system

• Done in other existing or planned machines

• Doing them at high gain requires a large device





30




9.2 T, 500MW, Q=10







• These are very high visibility• Could be done in a small device at short(er) pulse • Others are not going to do these soon


30




9.2 T, 500MW, Q=10




• Some require a pilot plant• Some can be done offline in

parallel• We need to at least have a good

plan for all of them

• These are very high visibility• Could be done in a small device at short(er) pulse • Others are not going to do these soon


Customer Hypothesis:Demonstrating high gain plasmas and the key HTS technology would change the outlook, it would be attractive to private funders at 100s of M$.

Technology Hypothesis:High gain utilizing HTS magnets could make large rapid progress in a single machine for this price range.

Next step: Technical scoping analysis to firm up feasibility and identify risks

Then:Once we have a menu item, take it out into the real world, talk to potential funders and see if it is compelling enough. i.e. test hypotheses

31


A survey of popular media reveals that “breakeven” or “more energy out than put in” is a common metric to judge whether fusion is viable or not

“The goal for all these machines is to pass the

break-even point, where the reactor puts out

more energy than it takes to run it.”

- Time Magazine cover story, Nov. 2 2015

Power gain appears to be a good metric for fusion, it is long established, and it is high impact

32



How Close Are We to Fusion?




- Time Magazine cover story, Nov. 2 2015 “The only problem is we haven’t yet figured out

how to reach the breakeven energy point in

nuclear fusion—where we get out as much

energy as we put in—”

- Forbes article, Aug. 27 2015


32



Is Nuclear Fusion About to

Change Our World?









“Here’s the really important thing:

To be commercially viable, you have to

create more energy than the original energy

you used to heat the fuel”

- CNN article, Oct. 22, 2015


32




Start-Ups Take On

Challenge of Nuclear Fusion













- CNN article, Oct. 22, 2015“But on Earth, making hydrogen hot and dense

enough to sustain a controlled fusion reaction—one

that does not detonate like a thermonuclear bomb—

has been a challenge.”

- New York Times article, Oct. 25, 2015


32




UK Center to Shoot for

Fusion Record


















“This could bring JET up to the

coveted goal of “breakeven”

where fusion yields as much

energy as it consumes.”

- BBC article, Apr. 24, 2014


32



This is not a new trend


UK Center to Shoot for

Fusion Record


















“This could bring JET up to the

coveted goal of “breakeven”

where fusion yields as much

energy as it consumes.”

- BBC article, Apr. 24, 2014

[TFTR]…will achieve the combination of high

temperature, fuel density and confinement time

needed for the generation of more energy required

to produce the reaction, or “break-even”…

- New York Times article, Aug. 8. 1986

Fusion Machine at Princeton

Outheats Sun’s Core Tenfold


32




It is a long-established goal of the fusion community

It is a central goal of ITER, FIRE, BPX, CIT, Ignitor….

These devices attracted significant resources

ITER construction site

National Academies reports


33



If a high-gain compact experiment using HTS would be attractive…What are the technical challenges?



It is a long-established goal of the fusion community

It is a central goal of ITER, FIRE, BPX, CIT, Ignitor….

These devices attracted significant resources

High gain passes the “gut check”

It is the major milestone identified by start-ups attracting significant money

All the textbooks have a chapter, usually the first, dedicated to this

34


We work through the different subsystems from the inside out, seeing if our system is feasible.

𝑄 =𝑃𝑓𝑢𝑠𝑖𝑜𝑛

𝑃𝑒𝑥𝑡𝑒𝑟𝑛𝑎𝑙 ℎ𝑒𝑎𝑡𝑖𝑛𝑔

from ~1 to ~5

R0

Plasma

Shield/Blanket

Magnets

DivertorB0

Lets see how:

In a small HTS device affects these four areas, lets discuss how.

35


The plasma physics defines our operating space.We need to take what the plasma gives us.

R0

Plasma

B0

• Use a 0D plasma physics model based on empirical scaling relations

• Standard approach

• Use conservative plasma physics inputs widely demonstrated on tokamaks

SPARC ARC ITER Limit

βN 2 2.6 1.8 <2.8

fG <0.75 0.7 0.85 <1

q95 3 5 3 >3

H98 1 1.7 1 <1.7

• Self-consistently solve at different engineering parameters B0, R0, ε, κ, etc

• Output Q, Pfus, Pext, Ip, ne, Te, etc

• Check against existing devices and designsBottom line: Use existing, demonstrated plasma physicsto determine what is physically feasible

36


What if we gave up the requirement to shield for a long lifetime? …This fits well with the lean cycle outlook.

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Can’t shield for long

Reactor

To scale

Mu

lti-

nat

ion

alsc

ale

37

Q


The lower left, with 1<Q>5, 9T<B<13T looks like an interesting parameter range.

Nat

ion

alsc

ale

Co

mp

any/

lab

/u

niv

ersi

ty s

cale

Can’t shield for long

Reactor

To scale

Mu

lti-

nat

ion

alsc

ale

37

Q


This is ~10x smaller in volume than ARC, 10x larger than C-Mod.Similar in size to ASDEX-U, DIII-D, EAST, KSTAR, Tore Supra.

38


Such a device would make substantial fusion power,3-10x the current record.

39


A pulse length of ~10s is long enough to learn a lot. This is a major advantage over larger machines.

With SPARC, a lot of learning can now happen in 10s.

There are a lot of problems that are easier at 10s than 10 minutes:• Tritium issues• External Power• Nuclear issues• Cooling• Divertor heating

40


SPARC would operate at the PB/R, a figure of merit for divertors, of a reactor such as ARIES or ARC.

41


Three major first-wall problems

1. Avoid melting the plate

2. Avoid eroding plate

3. Thermal fatigue from many cycles

• Short-pulse, short-life experiments do not need to solve erosion problem, fatigue, and may not need active cooling

• Experience base:

• Surface sun ~ 0.06 GW/m2

• C-Mod q||~1 GW/m2

• SPARC q||~60 GW/m2

• Reactors q||~60 GW/m2

• Completely unexplored physics territory

• Physics models not yet predictive

• Uncertain if today’s physics solutions will project to the future

The divertor is problematic for any magnetically confined reactor device, it takes the immense heat.

R0 Divertor

B0

Bottom line: Treat this as a serious risk.Use all the known techniques.Find a solution for SPARC, it is ok if it doesn’t scale.

42


• 2 divertors (factor 2)

• 1° incident field angle (factor 60)

• Sweep strike point (~factor 10)

• Then see what fraction of power needs to be radiated to have solution for 10s pulse at full performance

Divertor risk mitigation strategy:Use all the techniques in the (current) book

Simulate Strikepoint sweep with 2 cm wide heat flux on 25 cm long divertor plate

43








q||=60 GW/m2 (PB/R=600), λq=0.3 mm (Bpol~2T)

43

Inertial cooled W tiles

frad required = 0.75

Tmelt








q||=60 GW/m2 (PB/R=600), λq=0.3 mm (Bpol~2T)

43

Inertial cooled W tiles

frad required = 0.75

Tmelt

ITER-style actively cooled W-monoblock

frad required = 0.5

Tmelt



A ‘standard’ divertor may be sufficient for the SPARC mission

Mitigation strategies identified thus far:

1. Run for shorter pulses

2. Draw from ITER technology and testing

• But increases complexity,

• Can beat it up since we have fewer pulses

3. Large scale strikepoint sweeping

4. Rely on seemingly reasonable radiative fractions

• Untested at these heat flux densities

5. Take it slow, learn as you go

6. Lower power by lower the plasma’s βN

7. Change divertor to carbon (groans)

Anticipate further research in this area to inform options.

44



A ‘standard’ divertor may be sufficient for the SPARC mission

Mitigation strategies identified thus far:

1. Run for shorter pulses

2. Draw from ITER technology and testing

• But increases complexity,

• Can beat it up since we have fewer pulses

3. Large scale strikepoint sweeping

4. Rely on seemingly reasonable radiative fractions

• Untested at these heat flux densities

5. Take it slow, learn as you go

6. Lower power by lower the plasma’s βN

7. Change divertor to carbon (groans)

Anticipate further research in this area to inform options.

45

Air bags weren’t the end-all-be-all of landing on Mars…

…but they allowed Pathfinder to quickly prove potential and generate momentum at low cost.

Showing that Mars was interesting and de-risking other things

generated the budgets that enabled us to get better at landing.

Pathfinder landing 1997

Curiosity landing 2012


By drastically thinning the shield the magnet is no longer protected from neutron damage or nuclear heating. (but the device is small!)

R0

Shield/Blanket

B0

The shield/blanket serves 3 purposes:

• Protect the magnets from neutron damage to the superconductor and insulator

• Limits the lifetime of the machine

• Absorbs the energy from the fusion power

• Avoid heating the cryogenic magnets

• Heat for power conversion

• Breeds the Tritium for the fuel cycle

• To do these functions effectively the shield/blanket must be 1-1.2m thick

• But this makes the machine R0>~3.5m

• SPARC solution: Run with a thin shieldBottom line: Determine the magnitude of the problem created by making the shield/blanket much thinner

46


TF Coils

ZrH2 Shielding

Plasma Volume

We created a new 3D parametric tokamak builder for MCNP to examine SPARC neutronics issues

Top view of

the tokamak

Side cutaway view of the tokamak

At the core is MCNP (Monte Carlo particle transport code from LANL), the gold-standard in neutronics

• C++ code parametrically builds a high-fidelity tokamak for MCNP input

• Takes Pfus(R, ε, κ, B) from plasma physics model• 3D geometry

47


Top view of

the tokamak

TF Coils

ZrH2 Shielding

Plasma Volume

Winding pack

insulation

CICC with

insulation

Pancake

insulation

TF cross section

with HTS CICC

mockup

We created a new 3D parametric tokamak builder for MCNP to examine SPARC neutronics issues

• C++ code parametrically builds a high-fidelity tokamak for MCNP input

• Takes Pfus(R, ε, κ, B) from plasma physics model• 3D geometry• Including the HTS and insulator

At the core is MCNP (Monte Carlo particle transport code from LANL), the gold-standard in neutronics

Quantitatively study SPARC neutronics issues:• TF HTS neutron flux >0.1 MeV • TF HTS insulator dose• Nuclear heating in TF coils

47


Under the conservative assumptions, SPARC HTS TF magnets survive for thousands of DT shots

B = 11T

B = 11T

Scan shield thickness and R0 to reach limits:• Insulator (polyamide) limit: 10 MGy is

conservative [1]• HTS limit: 3x1018 n/cm2 is conservative [2]• Inner leg is the limiting point

[1] Minervini, J. V et al., 2011. Electrical Insulation issues for a Fusion Nuclear Science Mission, PSFC Report RR-11-10

[2] Prokopec, R. et al., 2010. Characterization of advanced cyanate

ester/epoxy insulation systems before and after reactor irradiation. Fusion Engineering and Design, 85(2), pp.227–233.

Total global experience with DT plasmasin tokamaks: ~875 shots (~3000 seconds)

Example for R=150cm, shield=15cm, 10s shots

SPARC would increase DT operational experience >10x before burning out due to magnet irradiation

Shield doesn’t fit

BT [T] Insulator:

@10 Mgy

HTS:

@3x1018cm-2

9 ~9800 shots ~16800 shots

11 ~4000 shots ~6900 shots

13 ~1900 shots ~3300 shots

48


SPARC magnets are exposed to high nuclear heat loads due to minimal shielding, large solid angle

Nuclear heating is assessed at the inner leg, where space is the most limited and the heat load will be highest

Example: R=150cm, shield=15cm, ε=1/3

BT = 11T

• Cryogenic magnets (SC + structural case) are sensitive to volumetric nuclear heating• Worst case: TF magnet quench• Bad case: performance limits (e.g. shorter pulse length)• All cases: lower operating temperature = higher sensitivity

Volumetric cooling points of comparison:• Very high for a LTS magnet: ITER is <0.01MW/m3

• Moderate for a boiling LN2 system• Moderate for a 1phase water system: Car radiator ~ 1MW/m3

• Very low for a boiling water system: Fission BWR is > 50MW/m3

BT [T] TF heating [MW/m3]

9 ~1.0

11 ~2.5

13 ~5.2

49


The high critical temperature of HTS allows operation at 20-30K, where magnet heating can be handled.

• Material properties are highly dependent on temperature at low temperatures

• Changing operating temperature drastically changes cooling capabilities

50

4.2K

20K

300K

LHe LH2 LNe LN2Boiling point K 4.2 20.4 27.1 77.3

Carnot efficiency W/W 70 14 10 3

Steel heat capacity kJ/kg/K 2.6 14 23 0.2Thermal conductivity of steel 10-3W/m/K 0.29 2.2 3.1 7.9

• LHe is unattractive

• LH2 and LNe are more attractive

• Allowing the magnet to adiabatically heat to 30-35K from 20K works for <2-5MJ/m3 (<0.2-0.5MW/m3 )

• This is likely not effective enough

• Forced single-phase flow is marginal



51

LHe LH2 LNe LN2

Boiling point K 4.2 20.4 27.1 77.3Liquid heat of vaporization kJ/L 2.6 32 104 161

Gas volume from boiling m3/kJ 290 26 14 4

Critical boiling heat flux kW/m2 10 50 60 200

• Boiling LH2 or LNe2 is very effective compared to LHe

• Thermohydraulic calculations show a reasonable TF cooling channel arrangement can be done using 2-phase flow for LH2 and LNe

• There is extensive test data in cooling 2-phase flow in LH2, some from LNe

• SDI reactors, nuclear rockets, rocket engines

• These cryogens behave classically

• Extensive user-base for managing them

• But never been used to cool a superconducting magnet (because HTS is new)

LHe LH2 LNe LN2

Liquid vaporization rate L/s 392 32 9.6 6.2Gas production rate (Tboil) m3 gas /s 2.9 1.7 1.2 1.1Gas production rate (STP) m3 gas/s 290 26.2 13.6 4.2

• Example calc for 1MW:

LH2 cooled reactor



52

LHe LH2 LNe2 LN2

Boiling point K 4.2 20.4 27.1 77.3Liquid heat of vaporization kJ/L 2.6 32 104 161

Gas volume from boiling m3/kJ 290 26 14 4

Critical boiling heat flux kW/m2 10 50 60 200

• Boiling LH2 or LNe2 is very effective compared to LHe

• Thermohydraulic calculations show a reasonable TF cooling channel arrangement can be done using 2-phase flow for LH2 and LNe2

• There is extensive test data in cooling 2-phase flow in LH2, some from LNe2

• SDI reactors, nuclear rockets, rocket engines

• These cryogens behave classically

• Extensive user-base for managing them

• But never been used to cool a superconducting magnet (because HTS is new)

LHe LH2 LNe2 LN2

Liquid vaporization rate L/s 392 32 9.6 6.2Gas production rate (Tboil) m3 gas /s 2.9 1.7 1.2 1.1Gas production rate (STP) m3 gas/s 290 26.2 13.6 4.2

• Example calc for 1MW:

LH2 cooled reactor

Magnet cryogenic heating risk mitigation strategies

LHe won’t work, but LH2 (20K)and LNe (27K) are attractive

1. Increase shielding/decrease pulse length/lower power and use adiabatic heating

2. Forced flow at high pressure

3. 2-phase boiling heat transfer

Notes:

• Low temperature superconductors could not take anywhere near this heat load, and thus require a large shield

• But HTS is different, it can operate at T>20K, thus small shield

• This is only a problem in D-T pulses, not D-D

• Experience by other fields with cryogens not typically used in fusion

• Pulsed operation and small size allows accumulating cryogen in a big tank and then shoving it through the magnet to cool.


R0

Plasma

Shield/Blanket

Magnets

DivertorB0

Summary of technical investigations performed on SPARC thus far.

• HTS has useful properties for this mission• High field• High current density• High temperature• High strength

• Q= 1 to 5, Pfus =50-200MW • Away from limits• Small size allows short pulses

• Must survive high pulsed PB/R• Several mitigation strategies identified

Other technical work performed• Sensitivity to plasma physics assumptions• Tritium requirements, handling, licensing• Magnet current densities, stresses, tape requirements

• Thin shield allows small size device• Magnet survives for thousands of shots• Results in significant magnet heating

• Several mitigation strategies identified that work for HTS

53



1. Hypothesize high return problems and the appetites of

private funding

2. Identify the space plasma physics and HTS provides to

solve problem3. Identify physics,

engineering, and funding risks







Repeat until fusion is a reality or disproven

54



1. High-gain demonstration using HTS could attract funding at a

budget commiserate with mission

2. A R=1.25-2m, B=9-11T HTS device would be able to demonstrate high gain

3. Risks are divertor, magnet engineering, magnet heating,

cost and scope creep







Repeat until fusion is a reality or disproven

55

SPARC Underground PSFC IAP, Jan 14th 2016, SPARC mission 56

Remember our imagination exercise?A possible roadmap to fusion in 20 years.


SPARC

HTS model coilsand conductors

56



SPARC

International SC PMI test stands+

+


Divertor Test Tokamak

56

Local test stands

Large, jointed HTS coils



FNSF/Pilot Plant

SPARC


+




56


Test stands and loops


FNSF/Pilot Plant

SPARC


+ Test stands and loops

& nuclear facilities




56



A natural thing for the MIT PSFC to do:

• The PSFC invented the high-field approach.

• It just needed material science to catch up!

• The place with the most experience with high-field tokamaks and magnets.

• Many major contributors HTS (& LTS) research and magnet development.

• Close integration with nuclear, mechanical, materials engineering.

• It is the right size lab to get things done well, done quickly, done cost-efficiently.

• We have little to worry about by being perceived as “outsiders”.

• We might have some spare space soon.

• MIT is well equipped to seek and secure this kind of funding.

• This approach dovetails with the MIT climate initiative and MIT in general.

• A community of World-class scientists, engineers, technicians, students

SPARC: A tokamak with a focused mission:

57

To advance fusion energy by leveraging fast cycle times, private funding, new technologies, and the global need for carbon-free energy


BACK UPs

58


How is SPARC different from previous Cu high field device designs?Similarities:

• Similar size, field, current

• Utilizing same well identified advantages of high-field plasma physics

• Targeted toward the break-even/burning plasma mission

• Based on the idea of learning quickly and retiring a specific set of risks

FIRE, R=2.0m, B=10TQ=10, t=20s

Ignitor, R=1.3m, B=13TQ=inf?, t=5s

BPX, R=2.6m, B=9TQ=25, t=10s

• Nominally pulsed,

• Limited pulse number (1-5k)

• With options for AT work in DD

• Cryogenic magnets at 20-70K

• Magnet heating sets pulse rep rate

• Minimal shielding

• Small, exploratory nuclear mission


• Cu devices and ITER would have operated in different physics regimes (density, field, size, confinement time) making projection uncertain

• SPARC and ARC operate in similar physics regimes

• ARC is an interpolation in major device parameters from SPARC+ world facilities

• Cu TF waveform severely constrained the pulse, the plasma was never be in steady-state (especially BPX, Ignitor)

• SPARC plasma relaxes and could possibly do long-pulse DD

• We have learned new things about plasmas since then

• Mostly bad, mostly in the divertor

FIRE, R=2.0m, B=10TQ=10, t=20s


BPX, R=2.6m, B=9TQ=25, t=10s

How is SPARC different from previous Cu high field device designs?Physics differences:


• Cu TF fabrication required significant engineering R&D but was a dead-end

• HTS is on the path to a reactor

• Cu TF Ohmic heating had serious implications on the other engineering systems

• Not an issue for HTS

• Cu TF heating set rep rate even for DD operation

• HTS for DD can be long pulse/high rep

• Cu TF has lower overall current density and strength compared to HTS projections

• A larger magnet inner leg

• FIRE TF took >600MW from the grid to operate, serious siting requirement

• SPARC takes much less power (estimated <100MW)

• Majority of cost (7/10s) was in pulsed power supplies >1100MW

FIRE, R=2.0m, B=10TQ=10, t=20s


BPX, R=2.6m, B=9TQ=25, t=10s

How is SPARC different from previous Cu high field device designs?Engineering differences:


• We have learned how bad big programs can be

• SPARC purposely tries to avoid scope creep

• These were large government funded programs

• SPARC is a fast focused private-funded venture

FIRE, R=2.0m, B=10TQ=10, t=20s


BPX, R=2.6m, B=9TQ=25, t=10s

• These devices had long-range programs over long periods

• Climate change has placed a new emphasis on fast progress

• HTS provides a compelling narrative element

• These were good ideas anyway, being similar is not so bad

• SPARC is new, FIRE is the past

How is SPARC different from previous Cu high field device designs?Programmatic differences:


Avoid spending all your time making things that didn’t solve the highest value problem. Wait to solve those until you bootstrap.

The old way of tech development:

• Most companies fail because they

develop something nobody wants

• They spend all their time and

money based on bad assumptions

Ideas weren’t good


• Most companies fail because they

develop something nobody wants

• They spend all their time and

money based on bad assumptions

Tried and true solution:

• Test assumptions early with real stuff

• Figure out what the right thing to

build at each step is:

• Who will pay for it?

• Why will they pay for it?

• Don’t prematurely optimize

• You don’t know what you think

you know

New technology is hard because both the technology and the final customer are unknown.


But industry won’t build giant machines until the risk is retired.

Forbes. 2014. Largest electric utilities in the U.S. in 2014, based on market value (in billion U.S. dollars)*. Statista. Accessed 03 December, 2014.

49.9

40.9

40.9

38.6

28.7

24.6

20.7

19.4

19

18.4

15.6

15.1

14.2

14

13.2

0 20 40 60

Duke Energy

Dominion Resources

NextEra Energy

Southern Co

Exelon

American Electric

PPL

PG&E

PSEG Public Service…

Edison International

Consolidated Edison

Xcel Energy

Northeast Utilities

FirstEnergy

DTE Energy

Utility market value in billion U.S. dollars

$25B-$50B: Too

much

• Western governments don’t build

power plants. Utilities do.

• US electrical utilities:

• They won’t do the early steps

• But when it works they will be the

ones that will buy it and advance it

• Smaller/cheaper is better at first

Are risk adverseAre bottom line driven

Don’t do early-stage R&DWant simple systemsKnow their businessHave to justify to investors

Are really concerned about uncertainty

Value reliability and maintainabilityHave short payoff horizons

Need things to work for a long timeHave lots of moneyWant to make more money


But industry won’t build giant machines until the risk is retired.

Forbes. 2014. Largest electric utilities in the U.S. in 2014, based on market value (in billion U.S. dollars)*. Statista. Accessed 03 December, 2014.

49.9

40.9

40.9

38.6

28.7

24.6

20.7

19.4

19

18.4

15.6

15.1

14.2

14

13.2

0 20 40 60

Duke Energy

Dominion Resources

NextEra Energy

Southern Co

Exelon

American Electric

PPL

PG&E

PSEG Public Service…

Edison International

Consolidated Edison

Xcel Energy

Northeast Utilities

FirstEnergy

DTE Energy

Utility market value in billion U.S. dollars

$25B-$50B: Too

much

• Western governments don’t build

power plants. Utilities do.

• US electrical utilities:

• They won’t do the early steps

• But when it works they will be the

ones that will buy it and advance it

• Smaller/cheaper is better at first

Are risk adverseAre bottom line driven

Don’t do early-stage R&DWant simple systemsKnow their businessHave to justify to investors

Are really concerned about uncertainty

Value reliability and maintainabilityHave short payoff horizons

Need things to work for a long timeHave lots of moneyWant to make more money

If government isn’t going to do it, and industry isn’t going to do it yet, then…

Who is going to fund the development of tokamaks for fusion energy?

Why are they going to fund them?

How do the answers influence the development path?


Generally the federal funding path is loosing appeal for large projects.

• US Federal funding for basic R&D is

structurally compromised


• Large, mission-oriented projects with long

timescales are particularly difficult to get

done

• Industry and philanthropy/foundations

are the growth areas


• What do they want done?


Foundation/Philanthropy “shoot the moon” example

• Identify new technologies that drastically change what can be done

• Demonstrate each key piece at small scale

• Fundraise to scale up in risk-minimizing manner

Next-generation giant telescopes

US federal government doesn’t fund telescopes anymore (now 6% of observing time)Active optics, adaptive optics, and segmented mirrors lead to paradigm shift in telescope designBeat Hubble at a fraction of cost “Discovery machines”.

GMT: $0.7B TMT: $1.4B

Private

Private

new

estFed

eral

Ecstatic astronomer


Foundation/Philanthropy “filing holes” example

• Identify exciting opportunities that are being ignored by the federal government

• Agility and accountability of for-profit with vison of a non-profit

• Show that value can be added across the board by filling “hole”

Allen Institute for Brain Science: $0.5B

Federal research is too uncoordinated. Needs for “basic” stuff not being met.Map the brain, generate public resources, enable federal research to be more effective

Schmidt Ocean Institute: $0.2B

Schmidt paid for an oceanographic research ship since the federal government won’t. Open access science.


Market driven minimally-viable-product examples in space propulsion

• Don’t make exactly what you want at each step, but make something SOMEONE will

pay you for while still on your critical path

• Re-invest to solve new problems toward ultimate goal

Goal: Human space colonization

• Progressively larger rockets

• Create new markets in space

• Big enough to go to Mars… someday

~$4.5B

20

10

20

15

20

06


Private funding picks different projects than federal funding.And has different metrics for success.

Private funded projects:

• At the whims of the funders

• Investor visibility is important

• Must have a narrative

• Technology demonstration important

• “Outsider” approach is a plus

• Relatively large appetite for risk

• Solve highest return problem first

• Must start small and then scale up

• Performance leads to $ for next problem

• Someday payback with a product or show

quantifiable societal impact

Government funded projects:

• At the whims of the politicians/bureaucrats

• Constituency is important

• Narrative must serve nation

• Scientific payback is paramount

• Consensus-based

• Relatively low appetite for risk

• Long term programs on parallel problems

• Must show steady progress in understanding

• Feedback not tied to performance

• Vague and open ended goal


A simple plasma physics model is used to scope the available plasma physics operating space.

• Inputs:

• Geometry and magnetic field: R0, ε, κ, B0

• Plasma physics: H, τE scaling, q95, βN,

• Minor parameters: ne and Te peaking, dilution, Zeff,

• Self-consistently solve for remaining parameters such as Q, Ip, Pfus, Ptrans, Pext, etc

• Iterate over fG (within limits) to optimize Q

• Including radiation, dilution, cross-section dependence, etc

• Check model against existing designs: ITER EDA, ITER FEAT, FIRE, ARC, EU DEMO

• Varying R0 and B0 with other inputs fixed to map region

• Identify interesting operating widow

• Check sensitivity to assumptions

ε=0.33, κ=1.8, H=1, ITER98y2, q95=3.0, βN = 2, fG<0.95

Zeff=1.5, dilution=0.9, pressure peaking = 2


Precedent exists for small nuclear private T licenses, and novel reactor licensing is currently in flux

A Q>1 with short DT pulse / low duty cycle operation could potentially be licensed as research facility, avoiding triggering full regulation• Minimal activation, onsite tritium (grams)• More flexible engineering, operations• Reduce required resources, financial cost,

license timelines• TFTR operated in this mode (2g invessel)

Precedent exists for private tritium site licenses (~grams)

Including legislation to enable private nuclear companies and academia to have access to Natl. Labs for testing novel reactors via Nuclear Energy Innovation Capabilities Act (H.R. 4084):

https://www.congress.gov/bill/114th-congress/house-bill/4084/

“Enabling the private sector to partner with the National Laboratories to demonstrate novel reactor

concepts for the purpose of resolving technical uncertainty associated with .. scientific discoveries

relevant for nuclear… engineering”

Many private companies working to reform licensing of nuclear prototypes:

Someday full US fusion licensing needs to be tackled. This will take substantial resources.SPARC Strategy: Near term avoidance while accumulating momentum, partners, and resources

ITER >1000 g

Civilian National Labs 20-200g

D-T n generator manufacturers <~ g

Jewelers/Gun sight manufacturers ~0.2 g

Academic/medical bio <~0.1 g

a small high field torus for changing...

Documents