JASON on the B61 Life Extension Program

September 26, 2013 | 9:22 am
Stephen Young
Senior Washington Representative

At the request of Congress, in 2012 the independent science advisory group JASON reviewed the planned life extension program (LEP) for the B61 nuclear bomb—the so-called 3B option. This option includes modest changes to the nuclear explosive package (NEP).

The review (released publicly here for the first time) considered two questions:

  •  The extent to which the nuclear scope is required to enhance the safety, security and maintainability of a refurbished B61
  • Whether changes to the weapon will affect the long-term safety, security, reliability and military characteristics

Given the considerable hullabaloo around the program, JASON’s assessment is relatively positive:

  • The changes to the NEP projected in the 3B design are modest, prudent, and should enhance the maintainability of the refurbished B61 while providing relatively large performance margins of this system without putting at risk its already substantial safety and security capabilities
  • The changes to the B61 NEP will extend the time between LLCE [limited lifetime component exchange] events, but otherwise are not expected to affect significantly its long-term safety, security, reliability and military characteristics.

The most important takeaway from the JASON report is this: Should schedule problems develop (as they invariably do), the NNSA must focus on what needs to be done, not on what might be desirable.

But it is also important to note what the report did not look at and did not say.

But let’s start with the limited scope of the study. JASON only assessed the NNSA’s preferred Option 3B, although it does note that Option 3B is much reduced in scope relative to the more technically aggressive Option 2C that the NNSA originally preferred. (Option 2C was rejected by the Nuclear Weapons Council. As one official explained it to me, 2C is the Cadillac, while 3B is the Lexus. That is, both are expensive, but the 3B doesn’t quite have all the bells and whistles of the 2C.)

But these are only two of the seven different options that the NNSA developed.

The least aggressive of these seven options is presumably the so-called “triple-alt” option that Sen. Dianne Feinstein (D-CA) flagged when she first highlighted her concerns about the costs of the proposed B61 LEP. The triple-alt would only replace three critical components—the radar, the neutron generator, and the power source. The latter two are limited life components that must be replaced in any event—with or without a LEP. The NNSA now strongly objects to that option, arguing that it does not meet military requirements.

That still leaves four other options that JASON did not study, at least some of which are presumably less aggressive than either Option 2C or 3B. How many of the improvements JASON cites for 3B could be achieved with less effort and cost than what everyone agrees is the shockingly expensive current B61 LEP?

The cost question is a doozy. If the B61 LEP had stayed at around $4 billion as originally estimated, the program would probably have sailed through Congress. But once the DOD estimated the cost at $10 billion, and the NNSA at $8 billion, for somewhere around 400 warheads, heads started to turn.

And the improvements that JASON notes in Option 3B are relatively modest. The most positive thing the JASON report says about the new version is that it will require less work on the part of the DOD in the long run. That is, the modified warhead “will enable a significant reduction in DOD maintenance by lengthening the limited life component (LLC) exchange interval.” This refers to a substantially larger gas transfer system that, according to Hill staff, will allow the tritium supply to last up to 10 years, rather than the 3-4 years at present. (Tritium, a radioactive gas that boosts the yield of the primary of a nuclear weapon, decays at the rate of 5.5 percent each year and must be replaced regularly.)

The JASON report also notes that Option 3B would lead to “logical but modest enhancements to the safety and security of the refurbished B61 NEP.” The most notable improvement described is replacing the detonators with a safer but “well-proven” version already used in the W88 warhead. But, as the JASON reports notes, the B61 already has “substantial safety and security capabilities.” These include insensitive high explosive and a fire resistant pit.


Just when it is necessary to produce a modified B61 has been an evolving story. Originally the NNSA said it absolutely, positively had to be delivered by 2017. Then a year later, in 2012, the deadline was slipped to 2019. The JASON report notes that a major factor in this deadline was the arrival of the new nuclear-capable version of the F35 fighter aircraft, which had been scheduled for 2017 and then slipped to 2019. It has now slipped even further, to 2020 at least.

It is interesting to note what the JASON report says about other drivers for the schedule. It cites “political reasons involving our NATO allies” and “the Pentagon’s already strongly expressed displeasure at the inability to complete the W76 as scheduled.” In other words, the NNSA needs to keep on pace or our allies and the Pentagon may be upset.

That does not mean no work is required. As I wrote in an earlier piece, the NNSA claims that if the 2019 deadline is missed, by 2021 or 2022 the reliability of the warheads will begin to decline and it won’t be possible to certify them. Presumably that applies to the limited life components of the warhead; neither the JASON report nor the NNSA provides any details.

The more important point that JASON makes is that, to meet its schedule, the NNSA should focus on what has to be done, not what might be desired:

“In implementing important and desirable, but not essential, elements in the 3B program, there should be a clear understanding of their cost and impact on the schedule. These elements should be prioritized in the event that unanticipated program delays or cost overruns are encountered that could threaten meeting the FPU [first production unit] deadline.”

In other words, a significant portion of the work proposed for the B61 is not essential. It is someone’s wish list, either the NNSA’s or the DOD’s. Yet that wish list, the JASON report notes, could become the reason that the production schedule ends up slipping yet again.

That concern is what drives the Senate appropriation committee’s position: A simpler (and less expensive) life extension program would be more likely to be delivered on time and on budget.

Particularly given the NNSA’s track record of busting budgets and missing schedules, there is a certain undeniable logic to that train of thought.