Bob Peurifoy, former Vice President of Sandia national lab, was telling me about the “three eras” of the U.S. nuclear weapons stockpile. I thought I would explore the concept. As Bob knows, we are still stuck in the second era, but it isn’t for lack of trying.
The first era was the Cold War, when new weapons entered the stockpile regularly, massive numbers of nuclear weapons were produced and full-scale nuclear testing was frequent.
The second era was the post-Cold War period when production and design of new weapons, as well as full-scale testing, all stopped. The focus of the nuclear weapons complex shifted from developing and building new weapons to maintaining the existing stockpile.
Sustaining the Nuclear Stockpile
Thanks to significant efforts and investments, this effort has succeeded, far beyond many expectations. As lab officials and outside experts have stated repeatedly, we know far more now about how nuclear weapons work than we ever did during the age of nuclear testing.
In fact, just three years ago, a Livermore scientist won a prestigious award for solving a half-century old question about the “energy balance” between the primary and the secondary, allowing computer simulations to much more accurately model nuclear weapons, as verified by modeling previous explosive tests.
Trying To Do More
However, the work to maintain the stockpile has not kept everyone happy. That unhappiness has led to a push to enter the third age of the nuclear stockpile, where the United States seeks to develop and deploy new weapons without full-scale nuclear testing.
At times, the military has joined with the weapons labs in pushing for new weapons, in particular for the Robust Nuclear Earth Penetrator (see our cool/scary animation). First proposed in 2003, the RNEP sought to improve on the bunker-busting capabilities of the B61-11, the existing earth-penetrating nuclear gravity bomb in the U.S. stockpile. The RNEP project was still in the design phase when it was killed by Congress. That outcome, it is worth noting, resulted in large part from the opposition of the Republican majority in the House, where Rep. David Hobson (R-OH), chair of the energy and water appropriations committee, did not see the sense of investing in new weapons given the other challenges faced in the stockpile and complex.
Thus failed the first effort to push the U.S. stockpile into a third era.
New warhead proponents did not give up. The RNEP campaign was followed by the Reliable Replacement Warhead, an effort promoted largely by the weapons labs. Supporters of the RRW sought to portray it as NOT a new warhead, touting the fact that it would have no new capabilities and was based on a primary design that was developed but never fielded.
More broadly, the RRW effort became the linchpin for the effort to rebuild much of the weapons complex. NNSA documents called RRW the “driver” for complex transformation.
But the RRW fared no better in Congress than did the RNEP. Rep. Pete Visclosky (R-IN), who replaced Rep. Hobson when Democrats took over the House, stated that the RRW program “puts the cart before the horse,” and called on the DOE to focus on “reconfiguring the old Cold War complex and dismantling obsolete warheads.”
And Congress eliminated funding for the RRW, thus ending the second attempt to enter the third era.
A More Modest Approach?
With two strikes against it, the push has shifted from proposing new warheads to making significant changes to existing warheads. The new approach seeks to use Life Extension Programs—the current standard practice for maintaining the nuclear stockpile—as a vehicle to make major changes to warheads.
Previously, LEPs have largely (though not entirely) focused on keeping the weapons as they are. The general approach, particularly for the nuclear explosive package, was to replace parts with identical or equivalent components, and to generally avoid major changes. (The nuclear explosive package contains the plutonium-based primary and uranium-based secondary.)
That is not the path the NNSA is pursuing now.
The test case for this new approach is the B61 gravity bomb. DOE officials have described the redo for this warhead as the first “full scope LEP.” The LEP was aggressive and had multiple objectives, including:
- Integrate new Air Force delivery capability
- Consolidate (4) B61 modifications into a single bomb variant
- Improve weapon safety, use control and reliability
- Reduce special nuclear material
- Reduce maintenance and weapon exposure
- Improve physics margin
- Eliminate safety soft spots(!)
The Government Accountability Office, in its assessment of the program, noted “Unlike prior life extension programs, the ongoing B61 study was broadly scoped to accomplish a variety of goals—such as considering previously untried design options and concepts—in addition to replacing the bomb’s aging components.”
Problems along the Way
The path for the B61 has not gone as smoothly as the NNSA hoped.
First, the “untried design options and concepts” GAO mentions have, at least in one important area, been set aside.
Specifically, the NNSA was looking at installing multipoint safety and optical initiators, two advanced safety technologies that would have required modifying the warhead’s nuclear explosive package.
Multipoint safety seeks to lessen the chance of an accidental nuclear explosion if the conventional explosive accidentally ignites at more than one point nearly simultaneously. The current one-point safety requirement mandates that the risk of a nuclear detonation be no greater than one in a million if the conventional explosive accidentally ignites at one point, which official documents acknowledge is an “extraordinarily high reliability requirement.” The GAO notes that warheads in the current stockpile do not have multipoint safety, and even the NNSA does not consider the technology mature.
(I note that Bob Peurifoy states with absolute confidence that the stockpile actually already de facto HAS multipoint safety, and he would certainly know better than the GAO, but let’s set that aside. NNSA is still was declaring they planned to install it.)
Optical initiators use lasers transmitted via fiber optic cables to ignite the conventional explosives that compress the plutonium in the primary. (A patent that explains the process generically is here.) This technology has also never been fielded and is not mature, but in both cases the NNSA weapons labs believed they could make it work in time for the B-61 LEP.
Not Ready for Prime Time
However, the Nuclear Weapons Council, a joint DOD-DOE decision-making body, decided in December 2011 that the LEP should not include those technologies. Other safety and security features that do not require modifying the nuclear explosive package will be incorporated. Some components of the NEP will be “upgraded” much like is happening in the W76 LEP, where plastic parts and rubber cushions will be swapped out, but there will not be modifications.
Second, the cost for the LEP has skyrocketed. As recently as last year, in the FY12 Stockpile Stewardship and Management Plan, the NNSA estimated the LEP would cost $4 billion. However, a new estimate done by the Pentagon’s budget bureau states the cost will be $10.1 billion. (More on that in a future blog post soon.)
The cost increase caused Rep. Visclosky to bash the entire NNSA cost-estimating process: “The poster child of this inability to accurately estimate cost is the Life Extension Program for the B-61 bomb, the price tag of which has gone from $4 [billion] to $10 billion.”
This dramatic cost increase may lead to an even more modest LEP than currently planned for. In any event, as described above, the LEP will not be the “full-scope” program that the NNSA originally envisioned. Untested, unproven technologies, at least those inside the NEP, will remain on the shelf, at least for now.
Fourth Time’s the Charm?
That does not mean the weapons labs have given up, by any means. As we’ve described before, they still hope to combine the W78 and W88 warheads into a “common warhead” based on the W87. That warhead design could include a modified nuclear explosive package.
But, to date, the labs have failed to propel the United States into the third era of nuclear weapons, where new types of nuclear weapons can enter the stockpile without full-scale testing. A combination of Congressional resistance, technical challenges and good old common sense has held them back.