Thursday, January 07, 2016

The North Korean "H-Bomb" tests

The DPRK leadership has claimed that it has the ability to make an "H-bomb", When people think about this - they usually assume a high yield 100kT-1MT device, this is the wrong way to think about it.

MT yield devices were valid in the US-USSR context only because the two nations were in a weapons race. They were trying to show each other up (that is why impractical devices like Tsar Bomba was made). Also neither nation had very good missile guidance technology. So there was very poor CEP and the push towards high yields came about because of that factor. Once the high yields were specified by the end user the AECs on both sides were on the hook for testing such devices (all practically considerations non-withstanding).

That kind of high yield device is meaningless in the Korean context. Even if DPRK could make such a device, there would be of no deterrent value as they would have no place to test such a device and no means of delivering such a complex device to any target. No one would believe them if they claimed that they had one of those.

Internally - as you are all aware - the grasp of the Kim family on the DPRK leadership is always contested at some level. If they assemble a device of MT capability (even theoretically) the possibility of it falling into the hands of someone who wants to depose the Kim dynasty will be too scary to Kim Jong Un. So such a high yield device will most likely never be assembled inside DPRK.

A more rational approach from their perspective is to seek the know-how to make such a device and then leverage their control over the proliferation of such knowledge to blackmail the world. Essentially global nuclear security regimes rely on keeping the exact "recipe" (in as much as one exists) for high yield thermonuclear weapon secret. Demonstrating knowledge of even a part of the recipe provides a lucrative option for a cash starved entity.

If the objective is knowledge building, then a much smaller test is sufficient - there is no need to demonstrate a high yield.

This kind of thing was attempted on fission devices early on in Los Alamos. It was called "tickling the dragon's tail" - a very dangerous set of experiments that tried to push certain nuclear fission reaction rates in a controlled fashion. This is more difficult to do in a fusion context because you have to use a fission reaction to kick-start a fusion reaction. Fusion reactions typically happen when nuclei collide at extremely high speeds. Those conditions are not easy to produce in a highly controlled fashion.  Perhaps the DPRK scientists have figured out a way to do this - that prospect is very disconcerting.

That sort of thing IMO is an explanation for the Lars Erik De Geer analysis of the 2010 data set that showed fluctuations in the ratio short lived isotopes and long lived isotopes. Lars' work was greeted with skepticism because there was no seismic signature.

The relevant questions then become the following:

1) Can DPRK access enough Deuterium or Tritium to produce a technology demonstrator?

This part is hotly debated,

It could be imported from Pakistan (as Jeffrey Lewis hints). Or it could be made at the Yongbyon facility - from Li-6 irradiated at the 5MWth reactor, and then refined in the new hot cell facility (as David Albright pointed out).

Deuterium is relatively easier to get one's hand on. Let us assume that DPRK picked that up from somewhere. With their underworld channels, it should not be impossible to get a hold of. The Tritium is another matter.

2) How much Tritium can DPRK get its hands on?

As the amounts needed for demonstrating a boosting effect is a few grams and a best case scenario for a 20 MWth reactor is ~ 30 grams of tritium per year (per J. Wilson at SRNL). Even if we assume that the Yongbyon reactor is up and running for about 10% of the time a normal reactor is running for, the DPRK people would be able to pull together enough Tritium in a few years.

The amount needed for a boosting experiment is not out of reach of the DPRK people - though this is likely to be the rate limiter in carrying out too many experiments.

3) So what sort of experiments could DPRK carry out? 

This part is a little difficult to answer publicly for obvious reasons, but without getting into any details, the DPRK might want to show that

a) it can actually achieve a nominal fusion yield from heating by a fission primary - specifically show that they are getting fast neutron production.

b) that they can demonstrate the achievement of large amounts of x-ray production and significant quantities of ablation induced pressure.

If they do either of those - their claims to "thermonuclear know-how" will be pretty hard to debate.

4) How does one know that they have really done either?

If the North Koreans decide to publish the data on local radio-isotope abundance shifts then we have a way to examining their claims.

There is a precedent to this - India did that in 1998. India was keen to have people take its claims seriously - so Sikka, Falguni et. al. published the radio-chem analysis. If DPRK leadership wants to be taken seriously - they will need to do likewise.

There may be remotely monitored signals (NOT seismic - think Neutrino or Xe or Ba isotope shifts) that show enough signal to noise to be considered viable as potential supporting evidence.

For example, given the rarity of detecting neutrinos, if there was a sudden increase in the number of neutrinos detected at the exact same time as the DPRK claims of testing - then that is a signature that could be interpreted independently of anything the DPRK leadership might want to claim.

5) What about the IMS and Seismology?

That is useful only for relative magnitude estimation. So far within the error of the data, all the tests have been comparable in yield.

Seismology absent detailed local geophysical knowledge lacks the ability to produce absolute numbers.

6) What does this mean for the regional stability?

If the North Koreans are able to present evidence of achieving either 3a) or 3b) - then the will be able to leverage keeping their mouth shut for concessions. It may be that the concession they seek is a readjustment of the NLL - either in the form of transit rights to Chinese ports from Haeju or in the form of a complete re-alignment of the NLL with their proposed MDL.

In a very unanticipated way - these claims (if proven accurate) will stabilize the region. They will shore up the DPRK leadership and increase the economic stability of DPRK.

With greater stability DPRK will have more to lose by going balls-out-insane.

Therein lies the paradox of nuclear weapons - you can have that knowledge and claim the ability to kill millions of people but you can't behave badly with anyone after that. 

Added on the 11th...

Alex Wellerstein, who runs the RestrictedData blog has similar views. Note the reference to the DPRK press release.

"Through the test conducted with indigenous wisdom, technology and efforts the DPRK fully proved that the technological specifications of the newly developed H-bomb for the purpose of test were accurate and scientifically verified the power of smaller H-bomb."



9 Comments:

At 8:14 AM, Blogger Ralphy said...

NOKO regime is maintaining control over its population by claiming threats of imminent American invasion. This psycho terrorism of its own population can have serious consequences and be used for justification of just about anything.

 
At 1:07 AM, Blogger Ralphy said...

US is in conference with SoKo about moving nuclear assets back to SoKo. China considers this a threat. All nuclear US assets were removed back from SoKo in the 1990's. I would like to see a permanent missile defense system there if one is not already.

 
At 1:10 AM, Blogger Ralphy said...

Some tactical nuke Lance missiles would be nice too. Although currently banned by START.

 
At 5:26 AM, Blogger maverick said...

Hello Ralphy,

It is efficient to wait for either DPRK RC measurements or for the South Korean Xe-133/133m detection to provide meaningful signal to noise before any military maneuvers are carried out.

The seismic data is not of a quality that one can base any stable conclusions on. The shifts in the data are too close to the noise floor.

In any case, the real target is whoever in DPRK actually knows something about the coupling between fission and fusion processes. That target's identity is not known at this time.

A more strategic approach is needed at this time. This target must first be located as it is the real power center in DPRK now (Little Kim Jong Un's antics non-withstanding)

 
At 6:18 PM, Blogger maverick said...

If there is any proliferation of knowledge relating to boosting or radiation pressure from North Korea to Pakistan, then GoI will be left with no choice but to expand its knowledge of ablation pressure.

 
At 1:30 PM, Blogger ACR said...

Dear Mav,

Will the current GoI take that call in the event of evidence of such a proliferation reaching it ? Or will it cave in to pressure from the usual suspects ? As of now, even routine testing of ballistic missiles seems to have marginally slowed down since the final years of the previous GoI.

 
At 1:34 PM, Blogger maverick said...

Hello ACR,

I really don't know the answer to your question. I really don't know how the current residents of RCR thinks.

There have always been four largely independent discussions

1) Are the delivery platforms survivable and reliable?
2) Are the guidance systems viable?
3) Are there secure communication resources in place to guarantee early warning and continuity?
4) What are the most appropriate packages?

From my journeys through the land, I think we are seeing a majority of the discussion on (1) - reaching a closing point. With the launch of the cannisterized Agni V and the Arihant class making its way through trials, the massive proliferation of potential sites in which platforms can be based, I anticipate that in the next decade, there will be very few doubts about the survivability or reliability of delivery vehicles.

Guidance systems is always a hot topic, but as NPL has delivered the physics package of an atomic clock to the nodal agency, I feel a simple chain might be possible - i.e. a PIGA, a RLG and a RF signal (sync-ed to the NPL's clocks). This is not the complete solution to the problems of guidance, but it is a point at which a viable system can be said to have been reached.

Everything above was achieved in Sharm-al-Shaking Manmohan Singhji's time. That so-called "Nikamma PM" did a lot of work. In fact he did 10x the work of all the mother and sister lovers that called him names. He was all work and almost no talk. That is why I really think highly of him.

There are a handful of assets currently deployed in early warning roles, but these are airborne assets and maintaining a continuous airborne picket is quite inefficient. As you know satellite coverage can have gaps due to cloud cover and bandwidth issues. With regards, continuity - there are still many problems. The most obvious of which is the matter of secure extraction. I am told a MI-17 flight is always on ADA within a few minutes of where he is, but I find myself doing the maths like this - if one has 11 minutes time-of-flight for an enemy platform, then assume 3-5 minutes for threat identification (tracking, discrimination and fingerprinting) and communication. That leaves 6-8 min to perform an extraction and ensure continuity. I don't know if the extraction can achieve the 10 miles of separation between ground zero and the principal in 6-8 minutes. That seems like a very very short time to do anything. I don't even know if it makes sense to drill this scenario.

On the matter of package sizes, my views are well known. I find it pointless to bring this issue up without some clarity or reasonable conclusions being reached on the other three issues. Increasing package yield invites an escalation, if one does it and the enemy follows by demonstrating a similar yield - then one has entered a place where those 6-8 minutes have shrunk to 3-4 min. So basically without a "Wing Attack Plan R" option - there is no hope for viable deterrence.

Normally I would keep quiet about this - but given the removal of Dr. Avinash Chander and the strange case of the TIFR Director appointment, I am left wondering if someone is trying to advance this discussion ahead of its scheduled time. Ever since March 2014, I have been waiting for the proverbial "Santhanam's second shoe" to drop and the air to fill with more uninformative tripe about packages and how they "should be made.. blah blah blah".

 
At 1:36 PM, Blogger maverick said...

Does anyone have access to the minutes of the meeting between MEA and DPRK representatives last year?

Or are those still classified?

 
At 6:24 AM, Blogger maverick said...

It appears that Kim is not happy with the manner in which the veracity of his claims is being doubted.

This is similar to the stunt Pakistan pulled when people questioned its capabilities.

By threatening people, by talking openly about getting ready to use nuclear weapons - Kim (and the Pakistanis in the past) is attempting to deflect attention from questions about the credibility of their claims of nuclear ownership.

He is basically saying "So you *really* think we don't have this figured out? - well let me get ready to nuke you and see if you still believe that I don't have this terrifying capability". Kim Jong Un is trying to scare people into accepting his claim of deep knowledge of nuclear technology without actual proof.

This kind of worked for the Pakistanis because the Indians had no real intention of calling them out. The Indians interpreted the lack of data from Pakistan as a sign that for all their talk, the Pakistanis weren't sure if they had the capabilities themselves. As far as India was concerned, this knowledge offered a deep sense of security - Pakistan could have all the fissile material in the world but if had no real clue how to assemble a proper fission device - it was unlikely to be able to deliver anything in excess of 15kT to an Indian target. That is why George Fernandes at the time said "India is a big country, we can take a few hits."

Unlike India - ROK is a small country. ROK can't take even a 1kT hit from DPRK. Given the position of ROK in the global electronic and engineering products economy, the US and others can't afford to have ROK take a 1kT hit. The world simply has no choice but to call Kim's bluff.

Escalating with rhetoric was a very foolish strategy for Kim to follow - now if there is *any* flaw (even the slightest amount) in the data collected from the recent DPRK test - then he will look like a fool and deterrence will most likely fail.

We are now extremely close to a failure of nuclear deterrence.

 

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