When Peer Review Fails NIF Debacle

[mheslep]

"When Peer Review Fails" NIF Debacle

Anyone have or seen comments on

C.E. Paine, M. McKinzie, T.B. Cochran, "When Peer Review Fails
The Roots of the National Ignition Facility (NIF) Debacle", 2000
http://www.nrdc.org/nuclear/nif2/nif2inx.asp

Some primary criticisms:
-Cost escallation from $400M to $4B
-Beam energy derating down now to 0.6MJ, while the Halite-Centurion weapons experiments showed perhaps 20MJ is needed for ignition.

I'm unable to find any direct answers for the criticisms on the NIF site. I'll add one of my own: I don't see any handling of the 1st wall problem, which for a pulsed concept like NIF, must handle 10^8 more energy than a steady state design while protecting the beam entry points.

mheslep

 

[theCandyman]

I thought the Spallation Neutron Source in Oak Ridge was to be used for research into "first wall" materials?

Besides, I think NIF is supposed to be for weapons research, not energy production, although that is a nice addition to getting it to work.

 

[Morbius]

Anyone have or seen comments on

C.E. Paine, M. McKinzie, T.B. Cochran, "When Peer Review Fails
The Roots of the National Ignition Facility (NIF) Debacle", 2000
http://www.nrdc.org/nuclear/nif2/nif2inx.asp

Some primary criticisms:
-Cost escallation from $400M to $4B
-Beam energy derating down now to 0.6MJ, while the Halite-Centurion weapons experiments showed perhaps 20MJ is needed for ignition.

I'm unable to find any direct answers for the criticisms on the NIF site. I'll add one of my own: I don't see any handling of the 1st wall problem, which for a pulsed concept like NIF, must handle 10^8 more energy than a steady state design while protecting the beam entry points.

mheslep

mheslep,

The fact that the report is from the NRDC - National Resources Defense Council - should tell it
all for you - the report is a bunch of CRAP!

Christopher Paine and the NRDC have been against NIF from day 1.

Progress at NIF has been proceeding apace - with MAJOR accomplishments in 2007:

http://www.llnl.gov/nif/project/news_NIF_leapsforward.html

As far as the power of the laser, NIF has already demonstrated that a single beam can develop
10.4 kJ of ultraviolet light [ the Nd-Glass laser actually produces near infrared which is then frequency
tripled to ultraviolet by KDP crystals ]:

http://www.llnl.gov/nif/project/news_nel1.html#doe

When all 192 independent beams are online - each producing 10.4 kJ - the entire laser will have
an output of 2 MJ which EXCEEDS the design target energy for NIF. I don't know WHERE
Paine came up with the idea that NIF had been "derated".

NIF was designed WITH the full results of experiments done on Nova, Omega, and the
Centurion-Halite program in mind.

http://www.llnl.gov/etr/pdfs/12_94.1.pdf

As the report states, the NIF concept was reviewed by the National Academy of Sciences,
and DOE's own prestigious review group, the JASONS.

I don't know where Paine got his cost escalation number from; but NIF was NEVER projected to
cost only $400M. NIF's predecessor, the 10-beam Nova laser; cost more than that! Only an
IDIOT would project that the much more ambitious 192-beam NIF would cost only $400M.

Recommendation #1 by this NRDC paper from 2000 states that NIF should be deferred until LLNL
built and operated a single beamline for NIF. That is EXACTLY what LLNL did and completed in 1994.
The laser was known as "Beamlet" and there is a picture of Beamlet
in the following article:

http://www.llnl.gov/str/Powell.html

NIF consists of 192 lasers of the Beamlet design. If one is going to make 192 identical
copies of the Bemlet for NIF; I don't see the merit in the NRDC recommendation that
LLNL should first build an 8-beam laser, then a 48-beam laser... The ONLY reason
I can see to do that is to draw out and delay the program and run up the costs. That
of course is EXACTLY what NRDC would like to see happen - because it would give
impetus for Congress to kill the program; which is the result NRDC hopes to achieve.

NIF did have cost overruns - due to bad management, NOT technical problems. From the
American Institute of Physics:

http://www.aip.org/fyi/2000/fyi00.006.htm

"The University of California President's Council National Ignition Facility Review Committee was
chaired by Steve Koonin, vice president and provost of the California Institute of Technology. The
committee's report (November 1999; 13 pages; can be accessed at
http://labs.ucop.edu/nr/nr112399.html/) found that "management deficiencies, rather than technical
problems, are the root cause of the cost and schedule overruns." The committee finds that Lawrence
Livermore National Laboratory, the University of California, and DOE all share the blame for poor
management of the project. The report identifies a series of management failings, including insufficient
technical definition and implementation plan; lack of effective system engineering and integration;
inadequate mechanisms to measure progress; lack of management attention at senior levels; a
do-it-yourself mentality that discouraged outside expertise; insufficient communication mechanisms;
and an ineffective review process.

The committee described three "contributing factors" to the overruns. First, the contingency funding of
15 percent was too low for a project of this size and complexity (the committee recommends about 30
percent). Secondly, the baseline cost and schedule were established too early, before the technical
definition and implementation plan were complete. Finally, some project activities suffered shortfalls in
funding. The report estimates a 12-18 month delay in design of some of the laser equipment, additional
delay in design of the laser and target system infrastructure, and corresponding cost growth on the order
of 30 percent of the total estimated cost (or about $400 million). Construction of the conventional facility
is about 70 percent complete and remains on schedule."

Perhaps THAT'S where Paine got his $400M number. The $400M is NOT the total cost of the
facility - it is an overrun of 30% on the $1.2B due to the factors listed in the second paragraph above.
As noted above, the $1.2B baseline cost was an underestimate. Congress and DOE wanted a
baseline cost from LLNL BEFORE the full technical design and implementation plan was complete.

As is pointed out above - much of the overrun was due to shortfalls in funding. When Congress cuts
the budget for the project - then NIF can't buy materials that are needed in a timely manner. Then
when those materials are ultimately purchased - the cost has gone up.

LLNL addressed the first wall problem LONG ago. In a commercial reactor, LLNL envisions that the
target could be surrounded by a "shower" of a molten salt of lithium, beryllium, and flourine. See the
HYLIFE-II on the last page of:

http://www.llnl.gov/nif/library/ife.pdf

In fact, one of the missions of NIF is to do tests to determine the performance of SEVERAL first wall
designs. First wall design has NOT been ignored - see page 6 and Figure 7:

www.llnl.gov/nif/icf/icfpubs/qrtly_reports/jan-mar95/Logan.pdf

Once again, we have another thoroughly DISCREDITED report from NRDC. In my opinion, I would think
they should give up - they already have ZERO credibility in the nuclear field. I guess they want to explore
the realm of NEGATIVE numbers.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Besides, I think NIF is supposed to be for weapons research, not energy production, although that is a nice addition to getting it to work.

Candyman,

EXACTLY! Although NIF has applications as a tool for ICF research - the PRIMARY mission for
NIF is part of the DOE's nuclear weapons program; Stockpile Stewardship.

That's why NRDC has nothing but BAD to say about NIF - they have been rabidly opposed to
the DOE nuclear weapons program.

Christopher Paine betrays his bias in his personal addendum to the report. He states that the
ICF program will only result in a proliferation of personnell trained in thermonuclear weapons
technology. The USA has always had a cadre of scientists trained in thermonuclear weapons
technology based at the two nuclear design labs, Los Alamos and Lawrence Livermore.
These scientists are bound by the USA's classification laws and procedures, and are not
allowed to disseminate nuclear weapons technology and information. When NIF is complete,
these scientists will operate just as they have done for decades; but instead of blowing holes
in the Nevada desert - their experiments will be done on NIF. The argument that NIF will
somehow increase the dissemination of thermonuclear weapons technology is unsubstantiated.

The main drive behind NIF was by the Clinton Administration's desire not to have to resume nuclear
testing. President Clinton wanted to have the CTBT - Comprehensive Test Ban Treaty - yet
President Clinton ackowledged that the US was going to maintain possession of nuclear weapons
for the indefinite future:

"As part of our national security strategy; the United States must and will retain strategic nuclear
forces sufficient to deter any future hostile foreign leadership with access to strategic nuclear forces
from acting against our vital interests and to convince it that seeking a nuclear advantage would be
futile. In this regard I consider the maintenance of a safe and reliable nuclear stockpile to be a
supreme national interest of the United States.

--President Wllliam J. Clinton
August 11, 1995

NIF is about the only device capable of doing experiments in the thermonuclear regime that had
heretofore only been accessible via underground nuclear testing. Since the weapons laboratories
needed to have access to that physical regime for the management and stewardship of the nation's
nuclear detterent; NIF was the only technology that could obviate the need for underground nuclear
testing.

Dr. Gregory Greenman
Physicist

 

[mheslep]

Candyman,

EXACTLY! Although NIF has applications as a tool for ICF research - the PRIMARY mission for
NIF is part of the DOE's nuclear weapons program; Stockpile Stewardship.

Fair enough, but then it should not be named the National IGNITION Facility implying the opposite.

 

[mheslep]

mheslep,

The fact that the report is from the NRDC - National Resources Defense Council - should tell it
all for you - the report is a bunch of CRAP!

Christopher Paine and the NRDC have been against NIF from day 1.

Progress at NIF has been proceeding apace - with MAJOR accomplishments in 2007:

http://www.llnl.gov/nif/project/news_NIF_leapsforward.html

That may be; I note that the NRDF report references itself frequently in the43 footnotes. However, many of the other references certainly are not 'crap' sources (Science, DOE reports, etc), and positing a press release from the owners of the $4B budget in response doesn't go far toward refuting the 'crap'. How about a GAO review, or some other peer reviewed work?

As far as the power of the laser, NIF has already demonstrated that a single beam can develop
10.4 kJ of ultraviolet light [ the Nd-Glass laser actually produces near infrared which is then frequency
tripled to ultraviolet by KDP crystals ]:

http://www.llnl.gov/nif/project/news_nel1.html#doe

When all 192 independent beams are online - each producing 10.4 kJ - the entire laser will have
an output of 2 MJ which EXCEEDS the design target energy for NIF. I don't know WHERE
Paine came up with the idea that NIF had been "derated".

NIF was designed WITH the full results of experiments done on Nova, Omega, and the
Centurion-Halite program in mind.

Can you comment then on the assertion, based on the Centurion-Halite experiments, that 20MJ are required for ignition and therefore even with complete NIF design goal success it would not come close to ignition?

 

[mheslep]

...
LLNL addressed the first wall problem LONG ago. In a commercial reactor, LLNL envisions that the
target could be surrounded by a "shower" of a molten salt of lithium, beryllium, and flourine. See the
HYLIFE-II on the last page of:

http://www.llnl.gov/nif/library/ife.pdf

In fact, one of the missions of NIF is to do tests to determine the performance of SEVERAL first wall
designs. First wall design has NOT been ignored - see page 6 and Figure 7:

www.llnl.gov/nif/icf/icfpubs/qrtly_reports/jan-mar95/Logan.pdf

Morbius -

Yes I see some nice graphics but no calculations, no numbers. Specifically with current wall materials what scale of power does NIF predict? No doubt a low megawatt reactor can be built, but 1GW? How does one protect the laser or ion apertures in the reaction chamber? A liquid Flibe bath must be behind the first wall (?) which would do well at handling the averaged energy flux just as is planned for ITER, but the peak energy is the problem here (10^8 x greater than average) and wall would ablate away with every shot.

 

[mheslep]

...
As far as the power of the laser, NIF has already demonstrated that a single beam can develop
10.4 kJ of ultraviolet light [ the Nd-Glass laser actually produces near infrared which is then frequency
tripled to ultraviolet by KDP crystals ]:

http://www.llnl.gov/nif/project/news_nel1.html#doe

When all 192 independent beams are online - each producing 10.4 kJ - the entire laser will have
an output of 2 MJ which EXCEEDS the design target energy for NIF. I don't know WHERE
Paine came up with the idea that NIF had been "derated".

Apparently the assertion comes from this '99 NIF report (reference [6] by Paine et al):
http://www.nrdc.org/nuclear/nif/nif1104.pdf
that states in several places that as of '99 the optics could only only tolerate 3j/cm^2 though they hoped for 8 J/cm^2; 3 J/cm^2 * NIF beam size=pi*20cm^2 = 3.8kJ per beam; with 192 beams ~ 0.7MJ. Your links indicate the optics limits have been much improved recently.

mheslep

 

[Morbius]

Fair enough, but then it should not be named the National IGNITION Facility implying the opposite.

mheslep,

It wasn't LLNL's idea to call it that, anyway.

Congress MANDATED it - because it is supposed to achieve IGNITION.

Besides, calling it IGNITION does NOT imply the opposite - i.e. does NOT
imply that the facility is NOT a part of the weapons program.

The word IGNITION means that the fusion reaction is self-sustaining. What you want
to do with that self-sustaining fusion reaction is a totally different matter.

However, Congress was told that NIF would achieve thermonuclear ignition, and
Congress demanded that the facility have a name with the word "ignition" in it.

Dr. Gregory Greenman
Physicist

 

[Morbius]

A liquid Flibe bath must be behind the first wall (?) which would do well at handling the averaged energy flux just as is planned for ITER, but the peak energy is the problem here (10^8 x greater than average) and wall would ablate away with every shot.

mheslep,

No the liquid Fibre is NOT behind the first wall - it IS the first wall.

In the HYLIFE-II concept, the liquid Fibre is not a bath but a shower.

The liquid is pouring out of the shower head in a whole forest of spray; like a shower head
set to a series of "needle sprays" - but with the needles VERY CLOSE together.

The laser beams actually shoot in extremely narrow angles between the needle sprays.

The laser window ports don't "see" enough of the exploding fusion pellet to get damaged.

Dr. Gregory Greenman
Physicist

 

[mheslep]

Yes well since:

Congress was told that NIF would achieve thermonuclear ignition,

then its no surprise that

Congress MANDATED it - because it is supposed to achieve IGNITION.

Besides, calling it IGNITION does NOT imply the opposite - i.e. does NOT
imply that the facility is NOT a part of the weapons program.

The word IGNITION means that the fusion reaction is self-sustaining. What you want
to do with that self-sustaining fusion reaction is a totally different matter.

You said up thread, in all caps:

the PRIMARY mission for NIF is part of the DOE's nuclear weapons program; Stockpile Stewardship.

Ignition, which LLNL told Congress it would do, as I said implies the PRIMARY mission is energy development and that weapons research is not PRIMARY.

 

[Morbius]

that states in several places that as of '99 the optics could only only tolerate 3j/cm^2 though they hoped for 8j/cm^2; 3j/cm2 * NIF beam size=pi*20cm^2 = 3.8kJ per beam; with 192 beams ~ 0.7Mj. Your links indicate the optics limits have been much improved recently

mheslep,

I think you and others are misreading what is meant here. It's NOT that the '99 optics could not tolerate
8 J/cm^2 at all; but how much deterioration the optics would see; and what the frequency of replacement
would be. That's basically an operational issue for NIF.

The implication of the NRDC article was that the optics could only handle 3 J/cm^2; therefore the
system couldn't achieve its objective which required 8 J/cm^2 That was NEVER the issue.

The question is how many shots at 8 J/cm^2 could the system withstand before some of the optics
needed to be replaced. The '99 optics could only withstand fluences of 3 J/cm^2 without degradtion;
i.e. they would not be sacrificial components.

If one had to live with the same materials available in '99; then parts of the system would be
sacrificial.

However, as the Technology Review article stated; there wasn't really a question of whether the
damage thresholds could be increased; but whether the project would get the funds and time to do the
necessary research. They stated that in any project of the size and scale of NIF, there would always
be technology development in the process of building the facility - it really isn't practical to do all
the technology develpment up-front.

Again, much of the program was really pushed forward by the desire of the then Clinton Administration
to have the Stockpile Stewardship program up and running, including an experimental facility
capable of reaching the thermonuclear regime; in time to support the Comprehensive Test Ban Treaty.

Much of the problem here with damage thresholds had to do with "cleanliness". The question was how
to get the NIF laser bay clean and dust free. After all, prior to the installation of the lasers; the laser
bay would be a construction site. The laser bay was going to have dust and dirt in it as one would
find in any industrial setting or any construction site of a commercial building.

It's the dust in the air, when it alights on optics and gets blasted by the lasers, that absorbs energy
which is deposited in the optics on which the dust sits. There was a big question as to how the
laser bay was going to be cleaned and how successful that cleaning would be. Like any research
project; those problems were worked and solved.

The laser bays have been cleaned. The optics is assembled in a clean room, and sealed in what are
called LRU's - Line Replaceable Units. These are big "cells" that are transported by special robots
from the clean room assembly area to the laser bays [ see 3rd picture in 3rd row shows 2 of the
3 robots]:

http://www.llnl.gov/nif/project/lib_highlights.html

As reported in the update I cited; the optics technology development problems have been resolved
and that the NIF beamlines are performing at levels exceeding design specification.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Ignition, which LLNL told Congress it would do, as I said implies the PRIMARY mission is energy development and that weapons research is not PRIMARY.

mheslep,

NO - that doesn't follow AT ALL!

Congress was told that NIF would achieve ignition.

Congress was also told that the PRIMARY mission for NIF was the Stockpile Stewardship program.
In fact, NIF was funded under the "umbrella" of the Stockpile Stewardship program, of which it is a major part.

Whether the system achieves ignition or not is a technical goal - do you get more energy out of the
system than you put into the system. Another way of looking at this question is to realize that it
is the same as asking "How much energy do you get out of the system?"

If you put "Y" Joules into the system, and get out "X" Joules, and X < Y; then you didn't ignite and
X is lower than Y.

However, if you get "Z" Joules out because you achieved ignition i.e Z > Y; then because of the
higher output "Z" - you can "visit" more space in the thermonuclear regime.

So whether or not NIF achieved ignition is another way of saying how useful it will be for visiting
regions of the thermonuclear regime that physicists would like to "visit" to do experiments.

Whether those experiments are in support of an energy program or a nuclear weapons program is
a totally different consideration than the physics goal of reaching ignition. BOTH applications would
be enhanced if the laser achieves ignition.

Dr. Gregory Greenman
Physicist

 

[mheslep]

mheslep,

No the liquid Fibre is NOT behind the first wall - it IS the first wall.

In the HYLIFE-II concept, the liquid Fibre is not a bath but a shower.

The liquid is pouring out of the shower head in a whole forest of spray; like a shower head
set to a series of "needle sprays" - but with the needles VERY CLOSE together.

The laser beams actually shoot in extremely narrow angles between the needle sprays.

The laser window ports don't "see" enough of the exploding fusion pellet to get damaged.

Dr. Gregory Greenman
Physicist

Interesting challenge. Fine control of molten spray in a vacuum. I imagine the pellet injection in such a bath is complicated too, but I suppose not overly. With regards to the laser windows, hmm. We're looking at an output of 20 to 40 MJ per shot? Assuming the energy release is ~ isotropic, and that the wall and windows might be, say, 1M away from the target then the wall flux is 100 to 300joules per cm^2 per shot, though still at a rate of 10 to 30 GW. I suppose steel, etc could handle that for a while but exposed thin film coated optics? With the radiation mostly as high MeV neutrons? No way to mechanically shutter in 10ns time frames.

EDIT: after more review of the beam path it appears that a) the optics are more like 2 to 3 meters away but b) the wedge lens exposure is also quite large - more like 10's to 100's of cm^2, the debris shield not withstanding.

 

[mheslep]

...
The laser bays have been cleaned. The optics is assembled in a clean room, and sealed in what are called LRU's - Line Replaceable Units. These are big "cells" that are transported by special robots from the clean room assembly area to the laser bays [ see 3rd picture in 3rd row shows 2 of the3 robots]:

http://www.llnl.gov/nif/project/lib_highlights.html

Cool, looks like a wafer fab clean room. Also, the growth of the large crystals is impressive.

 

[Morbius]

EDIT: after more review of the beam path it appears that a) the optics are more like 2 to 3 meters away but b) the wedge lens exposure is also quite large - more like 10's to 100's of cm^2, the debris shield not withstanding.

mheslep,

The optics are about 5 meters away from the target.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Interesting challenge. Fine control of molten spray in a vacuum. I imagine the pellet injection in such a bath is complicated too, but I suppose not overly.

mheslep,

Why would you think there is a problem with control of the spray in a vacuum.
Quite the opposite - there's nothing to perturb the spray - it just falls in laminar flow.
There's no turbulence to disrupt the flow - no entrainment of gas...

The pellet injection is simple too. The pellet injector is in the center of the "shower head"

You can devote as much area to the injector as you want. That is you put the injector at
the center of the shower head, and the first ring of molten salt nozzles can be at any radius
from the center that you desire.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Cool, looks like a wafer fab clean room.

mheslep,

Yes - cleanliness is one of the major factors in terms of damage.

Any little bits of dust and dirt that alight on the optics will absorb laser energy
and explode; which can damage the optics.

Dr. Gregory Greenman
Physicist

 

[mheslep]

mheslep,

Why would you think there is a problem with control of the spray in a vacuum.
Quite the opposite - there's nothing to perturb the spray - it just falls in laminar flow.
There's no turbulence to disrupt the flow - no entrainment of gas...

The nozzle exhaust of a rocket launch is a good example. Near sea level the exhaust trails vertically in column under the rocket, but at high altitude (low pressure) the exhaust column expands outward in all directions. Also, I would expect the spray to have some surface vaporization and out gassing, expanding into the path of the beam. Then, the spray must impact on some surface (1st wall?) from which it must back splash, mixing with the exploded pellet and housing debris. None of this must be allowed to enter the beam path and must all be completely evacuated prior to the next shot.

 

[mheslep]

mheslep,

The optics are about 5 meters away from the target.

Dr. Gregory Greenman
Physicist

Ok, how does one protect large optics ( the wedge lens) 5M away from a small thermo nuclear explosion?

 

[Morbius]

The nozzle exhaust of a rocket launch is a good example. Near sea level the exhaust trails vertically in column under the rocket, but at high altitude (low pressure) the exhaust column expands outward in all directions.

mheslep,

You don't understand anything about hydrodynamics.

You're just "guessing" based on "fuzzy feelings' of what might happen, without ANY
understanding of the physics.

The rocket nozzle is in a COMPLETELY DIFFERENT hydrodynamic regime; because the
flow is supersonic. Do you know why the nozzle of the rocket is bell-shaped - or divergent?

When you force a fluid through a "venturi" - a narrowing or constriction in the pipe; the
velocity of the fluid speeds up. When you force a fluid through divergent nozzle - it slows
down. The above is true IF the flow is sub-sonic.

However, if you have a sonic or supersonic flow; a divergent nozzle accelerates the flow.

The behavior of a hot supersonic flow at low ambient pressures tells you ABSOLUTELY
NOTHING about the type of flow one would expect in the molten salt shower.

Also, I would expect the spray to have some surface vaporization and out gassing, expanding into the path of the beam.

WRONG! The temperatures are not high enough for that to be of concern for the proposed designs.

Then, the spray must impact on some surface (1st wall?) from which it must back splash, mixing with the exploded pellet and housing debris. None of this must be allowed to enter the beam path and must all be completely evacuated prior to the next shot.

It's a very VISCOUS liquid - try thinking MOLASSES!

Why don't you THINK about the problems, how they might be solved, and do some research.

A LOT of very bright scientists worked years on this concept. Do you really think that one day
after you learn about the concept that you are going to be able to think up problems that the
scientists didn't think of and SOLVE?

Dr. Gregory Greenman
Physicist

 

[Morbius]

Ok, how does one protect large optics ( the wedge lens) 5M away from a small thermo nuclear explosion?

mheslep,

Here's a report that describes a lot of the features of the final leg of a given beamline:

http://www.llnl.gov/nif/icf/icfpubs/qrtly_reports/apr-june97/8-karpenko.pdf

The figure of 5m is NIF's distance; a commercial plant is not constrained to 5m.

Additionally, the large optical components are located outside the target chamber. There is
only a port in the chamber for the beam to pass. The shower provides only a very narrow
angle for the port to see the target.

Dr. Gregory Greenman
Physicist

 

[JeffKoch]

NIF is now complete, by the way, http://www.laserfocusworld.com/display_article/355517/12/none/none/TECHN/Construction-complete-on-National-Ignition-Facility,-%22world's-largest-laser%22 . National Ignition Campaign experiments start in July, with the first cryogenic implosion experiments starting in March 2010. 1.8 MJ-equivilent shots have already been demonstrated, and the facility has met all it's technical project completion milestones. Much work remains to be done, but it does appear that the author's concerns were misrepresented, probably for political reasons.

 

[mheslep]

NIF is now complete, by the way, http://www.laserfocusworld.com/display_article/355517/12/none/none/TECHN/Construction-complete-on-National-Ignition-Facility,-%22world's-largest-laser%22 . National Ignition Campaign experiments start in July, with the first cryogenic implosion experiments starting in March 2010. 1.8 MJ-equivilent shots have already been demonstrated, and the facility has met all it's technical project completion milestones. Much work remains to be done, but it does appear that the author's concerns were misrepresented, probably for political reasons.

Do you mean the author of the LFW article, or the OP piece from NRDC?

 

[Coin]

NIF is now complete, by the way, http://www.laserfocusworld.com/display_article/355517/12/none/none/TECHN/Construction-complete-on-National-Ignition-Facility,-%22world's-largest-laser%22 . National Ignition Campaign experiments start in July, with the first cryogenic implosion experiments starting in March 2010. 1.8 MJ-equivilent shots have already been demonstrated, and the facility has met all it's technical project completion milestones. Much work remains to be done, but it does appear that the author's concerns were misrepresented, probably for political reasons.

Some dumb questions if it is ok:

What results are hoped for in the July experiments?

What does "cryogenic implosion" mean and what results are hoped for in these experiments? (Google informs me that "Cryogenic Implosion" is a black metal band from the Ukraine. I will have to check that out when I get home...)

Also I am a little confused by this sentence in the article?

The energy level will be increased during the next several months, and when all NIF lasers are fired at full energy, they will deliver 1.8 megajoules of ultraviolet energy to a BB-sized target in a 20-nanosecond shaped laser pulse, generating 500 trillion watts of peak power--more than the peak electrical generating power of the entire United States

...but the NIF is in the United States ?! So where is the energy the NIF delivers coming from?

 

[Astronuc]

...but the NIF is in the United States ?! So where is the energy the NIF delivers coming from?

The electrical energy for NIF most likely comes from the commerical grid.

Note that while the power seems very high, the pulse width is very narrow.

20-nanosecond shaped laser pulse, generating 500 trillion watts of peak power--more than the peak electrical generating power of the entire United States.

20 E-9 s x 500 E12 W = 10 E6 W-s = 10 MJ.

Energy storage systems can accumulate energy over hours or days, and then release it very quickly.

https://www.llnl.gov/str/Payne.html
http://www.osti.gov/bridge/servlets/purl/305302-En4Axu/webviewable/305302.pdf

 

[JeffKoch]

Do you mean the author of the LFW article, or the OP piece from NRDC?

The OP link from NRDC, sorry if this was confusing.

 

[JeffKoch]

What results are hoped for in the July experiments?

Those experiments will begin to quantify the effects of laser-plasma interactions in large-scale hohlraums, and will set the maximum drive radiation temperature for future experiments intended to demonstrate fusion ignition and gain in the laboratory for the first time.

What does "cryogenic implosion" mean and what results are hoped for in these experiments? (Google informs me that "Cryogenic Implosion" is a black metal band from the Ukraine. I will have to check that out when I get home...)

I'm not familiar with that band, but cryogenic implosion means we will implode a capsule containing cryogenic hydrogen isotopes, which form a solid layer on the inside of the capsule. After many iterations to optimize implosion performance, the hoped-for result is a yield of DT fusion neutrons who's energy exceeds that of the drive laser used to generate the implosion (=gain). At that point we will claim victory, and we will continue to explore cryogenic implosions with the goal of optimizing them for fusion energy production in the form of power plants. I suspect we'll all be dead by the time we figure everything out and have competetive fusion energy plants operational, but this is a long-term R&D effort that might benefit our grandchildren and their descendents.

 

[Coin]

Jeff and astronuc, thanks much for the explanations!

EDIT: Just to update, having finally got a chance to check out the myspace page for the Ukranian "Cryogenic Implosion" I conclude they are decent if you're into that sort of thing but somewhat generic.

 

[JeffKoch]

EDIT: Just to update, having finally got a chance to check out the myspace page for the Ukranian "Cryogenic Implosion" I conclude they are decent if you're into that sort of thing but somewhat generic.

Sounds like my nephew's band, http://www.myspace.com/erebuswi . Not my cup of tea, but they have fun with it.

 

[JeffKoch]

Update: NIF dedication ceremonies were this weekend, it was quite the party with a wide array of government dignitaries in attendance. It's huge, it's real, and it works.

http://www.redorbit.com/news/technology/1697260/super_laser_as_hot_as_a_star_unveiled/index.html?source=r_technology

 

[mheslep]

Update: NIF dedication ceremonies were this weekend, it was quite the party with a wide array of government dignitaries in attendance. It's huge, it's real, and it works.

http://www.redorbit.com/news/technology/1697260/super_laser_as_hot_as_a_star_unveiled/index.html?source=r_technology

Well congratulations to all concerned on some substantial optical engineering. But 'it works'? The National Ignition Facility, works?

...NIF director Edward Moses said that a fusion reactions triggered by the super laser hitting hydrogen atoms will produce more energy than was required to prompt "ignition."

Not he hopes it will, or it might, it simply 'will'? What's published on this? I thought the Centurion Halite experiments indicated 20MJ were needed for ignition? Here we have something https://newsline.llnl.gov/_rev02/articles/2009/mar/03.13.09-nif.php" delivered to the target (still amazing), but is it known that this is enough for ignition?

 

[JeffKoch]

I thought the Centurion Halite experiments indicated 20MJ were needed for ignition? Here we have something https://newsline.llnl.gov/_rev02/articles/2009/mar/03.13.09-nif.php" delivered to the target (still amazing), but is it known that this is enough for ignition?

We don't know. This is cutting-edge physics research, we try to extrapolate from what we think we know based on past experiments (Nova, Omega, Centurion/Halite (all results are classified so take open literature commentary with many grains of salt)), but there's a non-zero chance that we've made a mistake. If we find that we've made a mistake, we'll work out how to fix it. Nothing is certain in this business, the same is true in any large experimental facility - we build bigger facilities in order to learn more, and that learning curve isn't always predictable in advance.