Talk:National Ignition Facility

Introducing myself

I am Lynda Seaver, the media liaison for the National Ignition Facility at Lawrence Livermore National Laboratory. NIF is undergoing some significant tests recently and I think the results would be of great interest on the Wikipedia page. So in the interest of full disclosure I want to introduce myself and let folks know I will be adding some info to the NIF page. Lseaveratnif (talk) 18:50, 29 March 2012 (UTC)Lseaveratnif

older material

On first reading of this page, the density of 1Kg/mL without context doesn't sound all that big a deal off the top of my head. Addition of a link for the "6 times the density of the sun's core" comment, and/or a reference point of 11.34g/mL for lead, would significantly help. - Omega (aka Erik Walthinsen, omega no at spam vcolo dot com) 22:52, Dec 16, 2005 (PDT)

The targets are held in place by natural spider silk. [1] - Omegatron 19:32, Apr 28, 2005 (UTC)

Status update

Taken from press release at LLNL http://www.llnl.gov/pao/news/news_releases/2005/NR-05-10-02.html

Inflation

"When first proposed in the early 1990s, the cost for a "super laser" was estimated at less than $700 million. Current estimates put the ultimate cost between $3.5 and $6 billion."

I think it would be a good idea to place a note that adjusts the 700 million dollars for inflation. Unfortunatly, I don't know the year the cost proposal was made. If someone finds out later on, they can use an inflation calculator. If we assume 1990 and compare to 2005, its approximatly 3-6 times as originally proposed. It's still a big under estimate but its less than what one who might not think to account for inflation would believe. --Dr. Eggman3 04:20, 26 March 2006 (UTC)

Inflation between 1990 and 2000 was 34%. It explains nothing of the problem IMHO, not even the original price bump to 1.1 billion. Maury 11:58, 13 September 2006 (UTC)

Frequency upconversion

I'm still a little confused about this. Is the primary frequency of the mainline laser in the IR? Or does the laser have a few fundamentals and the upconvertor is only changing some of them (which I consider less likely)? How effecient is the process? Maury 11:51, 20 September 2006 (UTC)

Answered my own question, article updated. Maury 12:21, 20 September 2006 (UTC)

Freq. tripling of the fundamental Nd IR line to 351nm UV on NIF approaches ~50% efficiency.--Deglr6328 09:04, 21 September 2006 (UTC)

OK, that parts better. But now how much energy is lost in the UV -> x-ray "conversion"? I'd like to get a figure on the total amount of x-ray energy delivered to the target, I think that would be very useful. Maury 00:41, 3 October 2006 (UTC)

Its significant. I don't know about exact numbers because it varies hugely depending on many many factors. The only reason they bother with it of course is because of its simillarity to the Teller-Ulam radiation case. The direct drive method is way more efficient. This 1999 NIF paper [2] claims a 85% efficiency of UV to X radiation conversion efficiency.... --Deglr6328 07:06, 3 October 2006 (UTC)

I'm reading that paper now... excellent ref BTW. OK, it seems that the conversion is very good, but there's the n(abs) number which is the big one I think. Also the paper seems to suggest that the delivered power to the hohlraum is 1.8 TJ, but I'm pretty sure that's the power before conversion into UV, which as you noted is about 50%. The paper is quite confusing on this point, because they seem to change their definitions. At the top they say the laser power is 1.8 TJ, but all the charts at the bottom have 4.7 MJ or less, and it's not at all obvious what they are talking about. I'll keep reading... Maury

Thanks for all the help Deglr! I worked all of your additions and reference into a new section that I think is fairly readable. I think the article has progressed tremendously in the last month or so -- in fact I'd claim it's likely one of the best intro articles on NIF available anywhere. Perhaps we should go for a featured article attempt? Maury 15:10, 3 October 2006 (UTC)

Sure. I've really enjoyed editing it with you! I'm not sure its ready for FA nomination though. Many details still need adding. I'd say once its about a third longer and double the citations it would be about ready. --Deglr6328 01:13, 4 October 2006 (UTC)

Darn, actually there is one more missing number -- how much energy is needed to pump the amplifiers? I now have the rest of the numbers; 4 MJ of IR comes out of the beamlines, that turns into a nominal 1.8 MJ of UV after upconversion, x-ray conversion eats up just under half of that, coupling with the target is fairly efficient and should result in between 600 kJ and 1 MJ being absorbed. 25% overall, which I consider quite good! That is expected to cause an ignition that results in 100 MJ of fusion energy being released. So if we know the amount of power dumped into those flashtubes, we can estimate the overall end-to-end gain. I didn't see this in the ref, but maybe I just missed it? Maury 15:14, 3 October 2006 (UTC)

File:Laser hohlraum target energy coupling.jpg

I think our numbers may be a bit off concerning the beam to hohlraum to target coupling efficiency....

The wall plug efficiency from electricity to 4MJ IR is just hideous. We're talking like ~1% efficient. The capacitors that fire the Xe flashlamps store an unbelievable 330MJ! [3] --Deglr6328 01:07, 4 October 2006 (UTC)

Youch. Well actually it's not that bad, they're going to get ~100 MJ back out, and with a spherical direct drive that would be more like 160 MJ if I'm running the numbers correctly. Do you know if the flashlamps fire once for each pulse? Or is there any energy left over that lets them fire a couple of pulses from a single pumping? Maury 20:16, 4 October 2006 (UTC)

They'll be lucky to get 2-3 shots off A DAY. The flashtubes fire once every 6-8 hours max. The Nd:glass heats up and becomes deformed, ruining the wavefront quality of the beam for hours after the shot until they cool down. So the sequence is: Xe lamps fire> Nd atoms into excited state population inversion > seed pulse is injected into beamline> beam is passed back and forth through the Nd glass slabs in the amp and through the spatial filter each 4 times (its switched using a PEPC[4]) to extract as much gain from the amps as possible before the pop. inversion is gone >beams are freq. converted and injected into target chamber. Remember, this all has to be done immediately when the lamps fire, the excited state decay time for Nd is like milliseconds at most (microseconds? can't remember). Do you have a link for the 160MJ number? I've never seen gain predictions that high! --Deglr6328 05:55, 5 October 2006 (UTC)

Great diagram! Now the number I had, 600 kJ -> 1 MJ, is directly quoted in one of those refs, the PDD one I think. The diagram seems to suggest a better UV-to-x-ray conversion, like 70%, and a much lower x-ray-to-capsule "delivery". Hmmm. Well at least now I clearly see why people think that magnetic confinement is the way to go! Maury 11:50, 5 October 2006 (UTC)

Oops, just saw your question there. The 160 MJ number is an estimate I made from the other numbers given in the refs. The one I mentioned in the first bit above stated that the fusion energy in the indirect drive configuration would be 100 MJ, and that was at a gain of 25. In the direct drive configuration it is expected the gain would be around 40. So I just did the conversion. I cannot find a real gain number for the saturn targets though, just "high". Maury 11:52, 5 October 2006 (UTC)

Nope, found those numbers too, the saturn targets peak around 37. So now we have direct refs for all of the gains and powers except the estimate I made above, but I believe it to be correct because the fusion power scales linearly with the gain in all of the other examples (which makes sense, because that what gain means!). Maury 12:30, 5 October 2006 (UTC)

In regards to efficiency, direct drive and fast ignition type schemes are theoretically much more efficient compared to indirect drive. While I don't have the numbers off hand, if you search the literature for "inertial confinement fast ignition" you should find some numbers. I believe the one I read a few years ago was from a Japanese Physicist. NIF is about 0.5% wall plug efficient and has theoretical rep rate between 6-8 hours. Replacing the Xe flash lamps with diodes can improve the laser driver efficiency better than an order of magnitude. For example, the MERCURY laser at LLNL is a design sutible for an ICF laser driver has demonstrated 10% wall plug efficiency and a rep rate of 10Hz. The Laser technology is steadily progressing. The logistics of target design, manufacture and delivery are probably the biggest challenges facing inertial fusion energy. Were potentially a few decades away from major break through that will make fusion energy a reality. However, I believe it's prudent to pursue both magnetic and inertial confinement.

Xenon or krypton?

Does anyone know what the gas mixture is in the flash lamps? The Xenon flash lamp article seems to imply that krypton is more likely, which might suggest a change to the article. Maury 22:13, 4 October 2006 (UTC)

Would you believe that I was JUST pondering this exact question today? I will look into it but I'm pretty sure they're mostly, if not all Xe. I think Kr is mostly used in arclamps and high rep. rate flashtubes. If the NIF tubes do have Kr I bet its only to make a penning mixture.--Deglr6328 04:37, 5 October 2006 (UTC)

I am unable to find a single refrence which says that the NIF lamps are filled with anything but Xe. --Deglr6328 05:01, 5 October 2006 (UTC)

Automated peer review

National Ignition Facility

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GA failed

I have failed this article according to the GA criteria. The article is only sourced for the last half of the article or so with entire sections for the first half lacking inline citations. Go through and add inline citations for any statements you think a reader may wonder about its verifiability. Make sure to fix up the section that has the weasel words tag and then remove it once the section is fixed. The article appears to be broad enough and has plenty of images (although see if you can space some of the beginning images out better). Once you fix these suggestions, consider renominating again or get a peer review first to get a better gauge on fixing any other issues I may have missed. If you don't agree with the review of the article, see Wikipedia:Good article review. Good job so far, and keep improving the article! --Nehrams2020 06:55, 19 March 2007 (UTC)

Shock Compression

To me it seems pretty obvious that if enough laser energy were directed at this "target" in a short enough time that the people at NIF could have a functioning nuclear bomb in their midst. In this article why is there no discussion of "shock compression"? This seems like such an obvious extension of their research.

I assume you meant to make this a new topic for the discussion.

That's what they're doing--making a controlled nuclear bomb. They direct a lot of watts (not energy) at the target. The amount of energy produced from fusion in NIF is around the number of calories in 150 candy bars (if they were burnt). So it isn't much of a bomb. 171.71.37.103 21:41, 6 June 2007 (UTC)

How was location for this project determined?

I excerpt from the introduction of the article as follows:

Then they must strike within 50 micrometers of their assigned spot on a target the size of a pencil eraser. Because the precise alignment of NIF's laser beams is extremely important for successful operation, the requirements for vibrational, thermal and seismic stability are unusually demanding. Critical components, weighing tens of tons, were located to a precision of 100 microns using a rigorous engineering process for design validation and as-installed verification.

Why on earth was this built in California, the state most infamous for seismic instability (earthquakes)? Shanoman (talk) 17:25, 31 March 2009 (UTC)

Um.... proximity to Lawrence Livermore maybe? Politics? —Preceding unsigned comment added by 166.56.100.129 (talk) 19:53, 31 March 2009 (UTC)

Good Article Review

I have re-listed this article for GA. Maury 17:34, 10 July 2007 (UTC)

Did you re-list for GA or did you only list at GA/R? If the article is listed at both, the nomination at GA/R needs to be withdrawn. LaraLove^T/_C 17:54, 10 July 2007 (UTC)

The Good article review has now been archived. Good luck with the GAC. Geometry guy 22:49, 10 July 2007 (UTC)

GA on Hold

GA review (see here for criteria)

1. It is reasonably well written.

   a (prose): b (MoS):

2. It is factually accurate and verifiable.

   a (references): b (citations to reliable sources): c (OR):

3. It is broad in its coverage.

   a (major aspects): b (focused):

4. It follows the neutral point of view policy.

   a (fair representation): b (all significant views):

5. It is stable.

   

6. It contains images, where possible, to illustrate the topic.

   a (tagged and captioned): b (lack of images does not in itself exclude GA): c (non-free images have fair use rationales):

7. Overall:

   a Pass/Fail:

I have placed this GA candidate on hold for the moment. Overall, it is very well written.

1. My main concern with the article is the lack of citations. The first citation encountered in the text is six paragraphs in. Additionally, the "NIF and ICF" and "Criticsm" sections are largely unsourced. ("Critics argue..." What critics?)
2. I think the sheer number of images detracts from the article. Text under the first image should be cut down severely; while I understand its importance to the article, it might work better as an external link. Keep the two diagrams and the picture of the fuel capsule, they add the most to the article.
3. Be careful about jargon, abbreviations especially. For instance, in the "Construction Problems" section, the article uses the abbreviation "LRUs" without telling what an LRU is. I think I'd also get rid of the bold words and clean up the first paragraph in the "Description" section.

Overall, I'd say you're very close though. Keep up the good work! shoy 01:10, 11 July 2007 (UTC)

The reason there are no cites in the first six paragraphs is because they consist of introductory material who's claims are re-made later (the first two) or are boilerplate text condensed from the fully refed main article (the next three) -- there is a ref in the 6th. The boilerplate is used across all of the ICF articles. The only paras below that without inlines are three in the NIF and ICF section, which, like the material above, are also historical notes and taken from fully refed articles. Every statement about the NIF itself is refed. I can't speak for the Criticsm section, not having edited any of it. Frankly, I'm not even sure it should be there, although that first statement is basically a truism. The debate between the magnetic and ICF approaches has been rancorous and ongoing for forty years now. How does one ref that though? Difficult to say,

As to the images, I really can't think of a better way to describe how the system works than use the image as a starting place -- that's why the first one ended up with so much text. It might be better served by moving this down into the Description section and simply pointing out parts with TLAs, but try as I might, I couldn't find a better lead-off image. I'm not really sure what to do about this, they're all interesting in their own right, but I would agree that together there are a lot.

I fixed LRU.

Maury 12:01, 11 July 2007 (UTC)

I added a gallery, but I haven't decided if it looks nicer or worse. Is it just me, or do galleries look poor? Maury 12:06, 11 July 2007 (UTC)

Correct me if I'm wrong, but I think that facts should be sourced the first time they're stated, but not any subsequent times. That way, it's easy for the reader to look back for the source, and they don't have to go hunting through the article. Similarly, I'd like the "boilerplate text" to be cited, even if it's just one source at the end of the paragraph. And the "Criticism" section really needs to be cited-- It may be true that there is controversy, but unless you can come up with a reliable source, Wikipedia can't say it (see WP:WEASEL). shoy 17:02, 11 July 2007 (UTC)

I think that facts should be sourced the first time they're stated, but not any subsequent times.

That's a stylistic interpretation, IMHO. If I'm going to cover the material in full fashion in the body, I put the ref there, where it is more "direct". IE, it is common to reduce entire paragraphs from the body into a single statement in the intro, placing the ref there removes much of the detail. Whereas the main body might have three paras with five refs, the intro statement might have one statement, and the five refs would be bewildering. There's no policy on this as far as I am aware, and it is by no means uncommon, every scientific paper I've ever read follows this style, for instance.

As to the critisms section, I'm happy removing it. Maury 17:41, 11 July 2007 (UTC)

I couldn't find any policy on it either. I would have written it differently, but what you've got is fine. As to the criticisms section, it really should be removed if there aren't any sources. shoy 18:18, 12 July 2007 (UTC)

Already done! (well, the offending portion anyway) Maury 21:04, 12 July 2007 (UTC)

Promoted. shoy 16:59, 13 July 2007 (UTC)

Shooting Pu or U on the NIF does not constitute a "subcritical" experiment. This erroneous statement was removed.

Ummm, what? The mass of the Pu or U is definitely subcritical! Maury 02:55, 19 July 2007 (UTC)

A "subcritical" experiment has specific goals that aren't necessarily addressed by a laser experiment which happens to utilize "subcritical" quantities of the materials. The "subcritical" reference is wildly wrong in the context of NIF experiments, for very specific reasons.

And I'm sure you'd be happy to define these "very specific reasons" and "specific goals", right? I'm not saying you're wrong, but you've offered nothing in way of support of your position. In support of mine, I point to the fact that NIF's budget and experimental schedule is dominated entirely by the NSP. I'm not convinced they consider ultra-density experiments with Pu so differently as you claim here. Maury 12:27, 19 July 2007 (UTC)

The rest of the sentence answers part of it - laser experiments are intended to provide precise equation of state (EOS) data, most importantly along a shock hugoniot (http://en.wikipedia.org/wiki/Rankine-Hugoniot_equation), for particular materials in particular parameter regimes, but subcritical explosions are intended to provide integrated weapon-specific data on performance in a fairly messy environment that can't provide precise EOS data, and doesn't need to in order to be successful. I'm not sure what "NSP" is, but the schedule and budget are dominated by ignition experiments, not by EOS experiments with nuclear materials. Just trying to be precise here.

GA review

At the risk of adding to the multitude of GA related-discussions for this article, I've asked for a Good Article Review of this article, since in my opinion it still does not satisfy requirements. Contributors and previous GA reviewers are welcome to contribute. Drewcifer3000 06:03, 22 August 2007 (UTC)

Where is the discussion? Maury 11:43, 24 August 2007 (UTC)

Corrections made on the target diameter (2 mm vs. 3) and the DT ice temperature (18+ K, not a few degrees). Invisiblemen 05:44, 10 September 2007 (UTC)

I've delisted this based on reviewers comments, but would encourage the editors to renominate the article at GAN. The main concern raised at the GAR was that some of the material in the article was not clearly traceable to reliable secondary sources in accordance with WP:RS. Geometry guy 20:52, 10 October 2007 (UTC)

The tenting material is in fact plastic webbing, not spider silk. Invisiblemen (talk) 14:00, 16 January 2008 (UTC)

On hold

So why have I put such a well written article on hold?

GA review (see here for criteria)

---

This is a nice piece of work, but it still has some shortcomings with respect to the good article criteria, but you can fix them easily.

1. It is reasonably well written.

   a (prose): b (MoS):

2. It is factually accurate and verifiable.

   a (references): b (citations to reliable sources): c (OR):

   The sources are not sufficient to cover the whole article, take the background section with not a single citation, or the fifth paragraph in the "description" section. "NIF and ICF" has similar problems, and so did the "criticism section". This problem might give rise to allegations of OR.

3. It is broad in its coverage.

   a (major aspects): b (focused):

   The article would be better if it had mentioned the people who had helped in its development a bit more.

4. It follows the neutral point of view policy.

   Fair representation without bias:

5. It is stable.

   No edit wars etc.:

6. It is illustrated by images, where possible and appropriate.

   a (images are tagged and non-free images have fair use rationales): b (appropriate use with suitable captions):

7. Overall:

   Pass/Fail:

I will gladly pass the article if these issues are addressed. Ah, so I do not forget, please use the CITE web template for the last citations. It is important to do so, for a GA and even more so for an FA if editors are taking that way. Good luck and see you in a week. Λua∫Wise ^{(Operibus anteire)} 17:03, 15 February 2008 (UTC)

It's a little hard to read the stuff above in "edit mode", so if I miss anything I blame the markup...

"take the background section with not a single citation"

The background section is a synopsis of the same section in the ICF article. References are provided in depth there, and after much argument the general consensus is that "copying references" is not really needed.

"has similar problems"

Can you be more specific here? One of the problems is that a particular para does not have a reference, but that's definitely not a GA requirement, or didn't use to be, anyway.

"CITE web template"

Since when did this become a GA requirement? And for the love of god, why?! The internal formatting of a non-visible markup element should not be the difference between a good and non-good article, IMHO.

Maury (talk) 17:22, 21 February 2008 (UTC)

I've re-written the criticism section, I think everything is reffed now. Maury (talk) 22:23, 21 February 2008 (UTC)

Actually, do we even need that section? Perhaps the last two sections could be combined? Hmmm. Maury (talk) 00:58, 22 February 2008 (UTC)

Ok, I'm looking over it as a whole to try to get a feel for some of the extra refs you wanted. If you see any honkers put a ref-needed and I have a good idea which one it came from so I can put it in quick.

I'm also thinking of greatly shortening the background section. I looked over the one in the Migma article, and while it could use some improvement itself, it's smaller, more comprehensive, and shorter too! If you wouldn't mind looking at that one, I'm thinking it might be a good idea to bring it in here during the GA. I'd also use the same one in the various other ICF articles - Shiva laser, Nova laser, HiPER etc. Maury (talk) 01:03, 22 February 2008 (UTC)

Extending the On hold period for 2 days

The final decision (fail or pass) will be made on the 24th of February.

Okay Maury, I agree with you on some issues and disagree with you on others.

First, The citation templates are not themselves required, the information they have is. Per WP:MoS which is referred to here clearly states that WP:verifiability is one of the major criteria. How is that related to CITE templates? They are related because web sites change, providing one url to back the whole paragraph is rather unreasonable. I know they are bulky, but are necessary. I am not objecting to the first sources, but rather to sources from 11-17 except 16. Access dates and titles must be provided. Do not agree?

I saw that you have rewritten the Criticisms section, certainly better than before. :)

The background section can be rewritten to make it more comprehensive and shorter.

Per WP:LEAD, the lead should summarise the article, which it does, but I think it would be better if some citations were used there, even if the same datum is referenced in a later section.

I hope you realise that I am not applying FA criteria on a GA candidate, and I also hope that I do not have harsh criteria. For the moment, I am leaning towards a Pass, but let's see what happens.

Cheers!

Λua∫Wise ^{(Operibus anteire)} 10:19, 22 February 2008 (UTC)

Is there a tool for converting the refs to cites? Something that you point to an url, type in anything it can't figure out, and then it inserts them? Maury (talk) 14:45, 24 February 2008 (UTC)

Hmmm...I have come across some tools that can do that, I think. I will do a quick search and get back to you. Λua∫Wise ^{(Operibus anteire)} 18:01, 24 February 2008 (UTC)

Okay, could this be of any help [5]?

There is some sort of an article here which might help as well [6].

Will you finish working on this article today, or should I defer the decision till tomorrow? Λua∫Wise ^{(Operibus anteire)} 18:07, 24 February 2008 (UTC)

Ignoring the use of CITE vs. REF, is there anything else that needs work right now? Maury (talk) 22:47, 25 February 2008 (UTC)

Yes, I have put some citation needed templates, they need to be fixed. Λua∫Wise ^{(Operibus anteire)} 17:59, 26 February 2008 (UTC)

Well I'm busy working on new articles, so you can just fail this one I guess. Maury (talk) 19:20, 26 February 2008 (UTC)

• If you're interested in really picky comments, the sentence "Its main roles will be the exploration of inertial confinement fusion and, through these experiments, exploring high-energy high-density physics and nuclear weapons for the United States." is not very well constructed (I wouldn't mention this if it wasn't so prominent, right at the top). "Exploration ... exploring" is uncomfortable, and, in any case, "exploring nuclear weapons" is probably not really what's meant. That would mean someone crawling around on top of a stockpile. It's also not absolutely clear which components the clause "for the United States" applies to. Sorry! —Preceding unsigned comment added by 86.133.48.221 (talk) 23:00, 24 February 2008 (UTC)

Yeah, I'm not a big fan of that sentence either. Hmmm... Maury (talk) 22:47, 25 February 2008 (UTC)

Failed "good article" nomination

This article failed good article nomination. This is how the article, as of February 27, 2008, compares against the six good article criteria:

1. Well written?: Pass

2. Factually accurate?: No, citations are needed. Many statements are left unsourced which could lead to accusations of OR and POV (especially in a topic of such scientific importance)

3. Broad in coverage?: Pass, although somethings need to be added per comments above.

4. Neutral point of view?: Pass

5. Article stability? Pass

6. Images?: Pass

When these issues are addressed, the article can be renominated. If you feel that this review is in error, feel free to take it have it reassessed. Thank you for your work so far.— Λua∫Wise ^{(Operibus anteire)} 14:17, 27 February 2008 (UTC)

Whoa

Aurawise posted a huge number of "cite neededs" on various locations around the article. The vast majority of these are covered in the citations already listed, often in the very same paragraph. Others are general background info that can be looked up in the articles on the ICF concept as a whole. Still others could not possibly be considered questionable (500 ps?! NEVER!). I might be verging on OWN here, but does anything else think these might be a little too much? Maury (talk) 16:41, 19 March 2008 (UTC)

Thank you LLNL!

I recently received a number of materials from LLNL, in particular Bob Hirschfeld, that have corrected a number of problems (thankfully mostly minor) and added up-to-date progress reports. Included were a considerable number of high quality references that are publicly accessible but somewhat difficult to find. I have also added a new paragraph on the new target designs, which had slipped under my radar and was a definite sin of omission. I believe the results speak for themselves. Thank you LLNL! Maury (talk) 23:55, 30 April 2008 (UTC)

This has evolved into a very nicely written and factually correct article, nice work. Invisiblemen (talk) 20:35, 25 July 2008 (UTC)

budget

I've heard other numbers, closer to 3.4 billion for the total construction costs of the project. Can anyone produce a citation? —Preceding unsigned comment added by 99.137.90.141 (talk) 23:46, 26 March 2009 (UTC)

Explicit discussion of the ignition chamber

Great article! I thought it was missing an explicit discussion of what exactly happens in the ignition chamber. Upon a successful ignition, is it expected that, say, 60% of the fuel will undergo fusion, and the result will be ... a fireball? How is the energy drained in such a way that the ignition chamber doesn't get destroyed? Tempshill (talk) 21:15, 31 March 2009 (UTC)

There does not appear to be any mention in the article about what happens to the resulting energy released from the fusion. Is the heat collected in the walls of the ignition chamber and used to drive a conventional generator, or does this particular test facility simply let the heat dissipate for now? Is this facility actually targeting break-even (electrical) energy production or is it simply a proof-of-concept device? — Loadmaster (talk) 20:51, 3 April 2009 (UTC)

NIF is purely an experimental device, and there is no attempt to gather any of the energy from the target chamber. Nor would the basic NIF design be useful for a power generating device, because the hundreds of MJ that go into the laser produce only ~30 MJ of energy. After conversion losses and such you'd be looking at 25 times as much energy in as you could get back out. There are some devices that may be able to make laser fusion practical, however, you might want to take a look at the HiPER article.

I think the idea of describing the results of the explosion is an excellent one! Doing a little conversion, I find that the 30 MJ is about the same as 5 kg of TNT. That seems like an excellent way to explain it. Maury Markowitz (talk) 23:28, 7 April 2009 (UTC)

How would the fusion energy be captured?

The article doesn't say how the energy created by ignition/fusion would be captured and distributed for use. This seems a significant omission, considering creating fusion energy for useful purposes is the main point of the facility. Dubiousraves (talk) 21:32, 1 April 2009 (UTC)

The NIF is not designed to capture energy, in the sense of electrical power generation. It's main purpose is the creation and observation of fusion reactions. Power generation is a "front" of the NIF. It's main purpose is to better understand nuclear reactions, for nuclear weapons. Since the USA is a member of the nuclear non-proliferation treaty, it's they only way to make sure the there nuclear weapons work as designed. As you may know, nuclear weapons do have a shelf life of roughly 50 years. The USA can "re-build" them, but not test them. So the NIF is the only way to test nuclear reactions, within there interpretation of the treaty... there is a lot of disagreement of the legality of the NIF. Hence why power generation, is used as a method, to discuss the operation of the NIF. You my not know this, but Hoya, a glass maker, who made the glass for the NIF lasers, has been under a boycott for some time. Power generation will be a spin-off of the NIF, but is not it's main purpose. Just to be clear, I'm not in disagreement of the NIF. I think it's quite fascinating, but I also realize its true purpose. Nebrot (talk) 10:45, 2 April 2009 (UTC)

You conflated the NNPT with the Comprehensive Test Ban Treaty. You'll need to cite sources for the above claims. Tempshill (talk) 18:05, 2 April 2009 (UTC)

I seriosly doubt the ability of this installation to get as much energy out of a reaction as it puts into it. Look at Iter, and how that structure, expected to cost over 10 billion (!) Euro, will not generate a single watt of elictricity to be distributed to consumers, because the technology is not yet there and ITER is simply a large research project. NIF is for weapons research, nothing else, and it becomes obvious when you compare it with ITER. -- DevSolar (talk) 15:18, 2 April 2009 (UTC)

I agree with the original poster that the energy capture issue isn't mentioned. That's probably because the NIF has no system for for it. However, there is a discussion of it at Inertial_confinement_fusion#Inertial_confinement_fusion_as_an_energy_source. Relevant to this article is how big of an explosion a successful test would produce. The article speaks of a hoped-for 700 tests per year. Presumably the resulting radiation, etc, would need to be contained in some manner. Are there any sources which discuss that aspect?   Will Beback  talk  21:33, 2 April 2009 (UTC)

Definition of Ignition

The definition of "ignition" (if any) used in the ICF community is not the same as that used in magnetic confinement fusion. The JASON report mentioned in the article says "Our working definition of “ignition and propagating burn” (often written simply as “achieving ignition” in this report) is a fusion energy yield at least equal to the laser energy absorbed in the target." In other words Q>1, using the terminology of magnetic confinement fusion. Note also that laser energy absorbed in the target is less than that delivered by the laser - but I don't know how much. A definition such as this really needs to go into the NIF article and other articles about ICF.194.81.223.66 (talk) 21:03, 2 April 2009 (UTC)

Odd, I just came to this page to mention the same thing. This is the first time I have heard "ignition" mean anything other than self-sustaining reactions, and suspected that it might have been a little slight-of-hand to allow a lesser goal to reached and still claim success. For instance, see this definition. In this case what the JASON report refers to is not ignition, but gain. This is also the definition used in the (somewhat disorganized) article on fusion energy gain factor here on the wiki. However, I have found several resources that suggest that both definitions are used:

The concept of ignition in fusion research is analogous to both those definitions of a fission explosion. The first definition of ignition is the creation of a self-propagating burn wave after the initial fusion reactions begin. This is a concept analogous to criticality in fission explosions. The second definition of ignition is that the energy output from the fusion reactions is more than the driver energy output (this is also called a gain of one and establishes the scientific feasibility of these devices). This is a concept analogous to fission explosions releasing more energy than the chemical high explosives used for compression.[7]

Further research would seem warranted. Maury Markowitz (talk) 12:40, 3 April 2009 (UTC)

"Test the theory of fusion power"

Orly? ~~

What the heck is LASNEX?

In the "LMF and Nova Upgrade" subsection of History, I read "Based on the LASNEX computer models,...". Using "the" to refer to LASNEX implies that the term has been previously defined, but this is not the case, it springs forth from the womb full-formed. Can this be expanded to say "LASNEX computer models developed by Biff McCool at Geek Heights University" or some such explication?

Other than that (and a minor thing with pourable buildings, which I changed), I was struck by how well-written and sourced this article is. Yes, it's full of acronyms and technical terms, but after all it's a super-high-power laser facility, not a toaster. (Although, hmm, it could probably do a nice job on a slice of seven-grain bread :)

Imagine my surprise then to read the last FAC review from a year ago. I guess that's why I'm not an FA reviewer. If anyone wants to give FA another shot, I'm willing to help with fetching water and mopping sweat off brows. I personally found the article engaging and informative from start to finish. Franamax (talk) 19:13, 10 June 2009 (UTC)

LASNEX should indeed be previously defined, as there is no article on that specifically. Adding it to that sentence would probably make it poor writing, so either before or after should do. --Izno (talk) 21:24, 10 June 2009 (UTC)

LASNEX is a computer program, I will add refs.

Thanks for the kind words, all too rare here in the wiki. As to the FA, it seems it broke on the rocks of the licensing of the images. There were a whole lot of people pretending to be IP lawyers, so I just gave up. Maury Markowitz (talk) 15:02, 30 June 2009 (UTC)

Personal history

Personal history is irrelevant to the discussion of NIF.Bsure (talk) 21:03, 25 January 2010 (UTC) Bsure (talk) 21:02, 25 January 2010 (UTC)

Could you explain that remark? --Orange Mike | Talk 00:23, 26 January 2010 (UTC)

The referenced article clearly states the PhD issue had nothing to do with NIF and neither had anything to do with the resignation due to "personal reasons". 66.27.92.27 (talk) 01:20, 26 January 2010 (UTC)

Problems like this are relevant to the history of this facility, why it took so long to be built, etc. --Orange Mike | Talk 01:37, 26 January 2010 (UTC)

The referenced GAO report does not name names - it states there were "many" reasons/people responsible for incorrectly budgeting for NIF initially. The character assasination that is intent here is based solely on a newspaper article. The article clearly is mixing two events and purposely misleading the facts. I don't think there is any reason to pick "one" name and make them the fall guy for all problems based on a NYTimes article. As mentioned elsewhere in this site, a newspaper article is not a defense to libel. If you insist on blaming one individual, it seems only prudent and unbiased to include his rebuttal - why would you object to that? I think you should stick to the basic facts and stop trying to place blame on one individual. Why so much negativity? It is unbecoming to Wikipedia in my opinion! —Preceding unsigned comment added by Bsure (talk • contribs) 01:54, 26 January 2010 (UTC)

I'm rather suspicious when a brand new editor shows up on such a passionate mission, what with how people try that all the time here and they're always sure they possess the one whole truth. However I've read through some sources and I'm OK with either removing the mention of Campbell's resignation or rewriting it (and much of the section actually). The cited source goes to some length to mention "world's leading experts in ultra-high-energy beams" and how the resignation was unrelated. Other reading suggests he never actually said he had a PHD, someone in the press office started calling him Dr. Campbell and he never said not to. And the problems came to light it seems as a result of a review that he himself requested. The Nature coverage (which is regarded as, umm, reliable) does mention "resigned...ostensibly because..." but focusses much more on the problems of implementation of the science, i.e. they forgot to include space for people and/or the proponents wanted a building small enough to actually build, clean-room provisions for the project, problems with the laser glass. Other sources talk about DOE as part of the project-management problem. I'm going to randomly dump various sources here as I close the windows, partly for my own convenience: orig OM reverted [8][9][10][11] I still haven't found whatever content is in the UC review by Koonan FPR, September/October 1999, p. 57. Anyway, I do agree there is not much relevance to the statement on Campbell's resignation appearing in this article unless it's more well-qualified. The rest of the section may need some looking at too, I'm not confident the description of the GAO report tells the full story, nor whether the section adequately describes the actual problems. It seems like someone lowballed the original cost and time estimate, but the sources I've seen are rather unclear on that. Franamax (talk) 04:56, 26 January 2010 (UTC)

I agree with much of what you said - not sure what you are "suspicious" about, but let's just applaud passion when you find it...in this current climate....most just "don't bother" to put forth the effort. At any rate, the section could use more detail about the many levels of problems - this is a highly technical effort -- the first of its kind -- hopefully, we will be reading all about its ignition successes in the future, but the initial problems could be more adequately described and the eventual steps to correct them. Much of this article focuses on the problems and criticisms.....needs more balance - the facility is the first of its kind and if experimentally successful, could be a major scientific advancement with kudos to the US - etc. And by the way....I applaud your passion and thank you, and the others, for your efforts! Bsure (talk) 18:20, 26 January 2010 (UTC)

NIF is hardly "first of its kind". It is, as the history demonstrates, literally a scaled up Nova. Nova was a scaled up Shiva. These things go back to the 60's. Maury Markowitz (talk) 11:26, 15 October 2010 (UTC)

NIF experiment gain question

I think the article is not clear enough on whole gain subject.

It said that whole amount of energy in capacitors is 400 MJ. Then in 3rd paragraph of 'NIF and ICF' I found that whole output supposed to be 45 MJ, at most 100 MJ.

How that correlated with media sources like this one -- http://news.bbc.co.uk/2/hi/7972865.stm

This "energy gain", as it is known, is key. If it works, NIF will release 10 to 100 times more energy than the amount pumped into the lasers to kick-start the reaction.

What does it mean? Can anyone provide explanation on NIF expected 'net gain' i.e ratio of energy output to energy input in clear form?

The article is using an artificially attractive set of numbers. They are comparing the power in the laser beam itself (1.9 MJ) to the fusion output (45 MJ). They are ignoring all the losses upstream from the beam. Actually I thought the article explained this well, but I guess it needs work. Can you offer some color on how I could improve that section? Maury Markowitz (talk) 11:18, 15 October 2010 (UTC)

PHELIX translation

Hi there, looking for someone, who's time and courage to translate and change the German written Wikipedia PHELIX [12] in a good English article. Best Regards --Commander-pirx (talk) 11:18, 23 November 2010 (UTC) ([13]

Semi-prot

I semi'd this as we were getting IPs rewriting the article to all positive stuff. Some of the sourcing looked dodgy as well. Can I suggest that if anyone has a problem with this, please raise it here and it can be discussed. If there is anything of the edit I took out that can be rescued, feel free to do it, but I wasn't happy at wholesale removal of apparently referenced material. --John (talk) 05:55, 28 September 2011 (UTC)

Would like to remove this statement from the NIF article: "Cochran described NIF director Edward Moses and his team as snake oil salemen." This is a personal attack on Ed Moses instead of an objective comment on the project. It's also inconsistent with Wiki's policy of not making personal attacks anywhere on the site, and with Wiki's editorial guidelines of maintaining a neutral point of view and not quoting from participants engaged in a heated dispute. Thanks. JacksIrving (talk) 01:25, 6 October 2011 (UTC)

I think a better solution is to simply remove the entire section. This was leftover material from an early version of the article that I felt uncomfortable deleting because it was well refed. However, it seems to add little that isn't better covered above. If no one objects, I'll simply cut it out. Maury Markowitz (talk) 12:20, 11 October 2011 (UTC)

The NIF has been operating and firing laser beams on target for over two years now. The criticisms section made sense several years ago, when there was still a debate about building the NIF and about what it should do, but that is now old history. Invisiblemen (talk) 23:03, 29 October 2011 (UTC)

Another section removed

There was a section headed with "Constructing NIF" that appears to be part of the major anon edits of recent times. There was some useful information in there, but reading over it it became clear it was a copy-n-paste from some external source - it referred to images that didn't exist, etc. A little googling brought me to this page, but I suspect this is scraped from another NIF page on the historical timeline. For now I've removed the text as possible copyvio, but I'd prefer to include sections of it if anyone wants to take a crack at it. Maury Markowitz (talk) 15:38, 31 October 2011 (UTC)

Happy to give that a try, and also include a bit more about how NIF is making progress toward ignition. Meanwhile, if there are no objections I'd also like to remove the last paragraph of the "Progress" section which is no longer relevant since NIF construction was completed over a year ago. JacksIrving (talk) 01:04, 15 November 2011 (UTC)

There now seems to be a section missing, with the jump from NIF Emerges to Re-Baseline and GAO Report skipping from 1994 to 2000 and the Re-Baseline section opening with "In the wake of these revelations," when no revelations are mentioned. --205.254.147.8 (talk) 15:16, 30 December 2011 (UTC)

I found several more examples of removed content that have been re-added. Maury Markowitz (talk) 18:55, 5 March 2012 (UTC)