—Rachel S. Cohen
A1C William Ray, 90th Missile Maintenance Squadron
maintainer, removes the screws holding the nose point of a Minuteman III
ICBM to the rest of the reentry system inside a payload transporter in
the F.E. Warren AFB, Wyo., missile complex, on Aug. 24, 2016. Air Force photo by SrA. Brandon Valle.
The National Nuclear Security Administration has canceled its previous plan to refurbish a warhead for use on the Air Force’s future land-based intercontinental ballistic missiles as well as on the Navy’s submarine-launched ballistic missiles, according to a December 2018 NNSA report to Congress that Air Force Magazine viewed Jan. 29.
“[NNSA] is no longer planning for an interoperable warhead program as previously conceived,” the report states. “NNSA has no plans to pursue a W78 life-extension program using the existing aeroshell.”
Instead, NNSA will pursue a safer but slightly more expensive warhead for the future Ground-Based Strategic Deterrent, the W87-1, which is expected to cost between $8.6 billion and $14.8 billion before accounting for the fissile pit inside. The program began in November 2018, according to the Government Accountability Office.
Pit production could add $300 million to $750 million to the program’s overall price tag, which includes the projected budget and activities like technology maturation, though that estimate may change based on a forthcoming weapon design and cost report.
Pursuing a life-extension program for the W78 warhead was projected to total $8.5 billion to $14.2 billion, according to NNSA. W78s are now deployed on the Minuteman III missiles that are spread across silos in Montana, North Dakota, and Wyoming, with the replacement warhead to follow in Fiscal 2030.
The warhead replacement’s updated price tag comes the week after the Congressional Budget Office revealed that modernizing America’s nuclear triad is now expected to cost nearly $500 billion through Fiscal 2028, including $61 billion to update and operate the ICBM enterprise. The growing figures could lend ammunition to lawmakers like House Armed Services Committee Chair Adam Smith (D-Wash.) who oppose the nuclear modernization effort in its current form, while proponents say a new nuclear triad is affordable.
While the two warhead replacement costs are similar, NNSA now argues reworking the W78 “would not meet military requirements and would present several significant challenges and issues."
A newly developed W87-1 would be an “insensitive high explosive,” which experts believe are safer because they are less likely than current “conventional high explosives” to detonate in an accident, like a fire or an unexpected impact. Insensitive high explosives meet improved Air Force and NNSA safety and security requirements, have improved controls to ensure proper launches, and can be more efficiently produced, according to the NNSA report.
In fact, switching to an insensitive warhead could potentially double the amount produced. Conventional explosives are separated from each other and handled one at a time to lower the chance of an accident that would trigger an explosion, but multiple insensitive explosives could be built in the same area at once.
“Operations on IHE-based weapons are conducted in bays that are designed with the understanding that the probability of high explosive detonation or high explosive violent reaction during weapons operations is essentially zero,” NNSA wrote.
A congressional source told Air Force Magazine the US has prioritized nuclear safety and security since the end of the Cold War at the risk of fielding less responsive or reliable munitions, and that converting the warhead to an insensitive variant is seen as a step in the right direction.
Fitting an insensitive explosive in the Minuteman III’s current Mk12A aeroshell—which carries and protects the nuclear warhead inside—poses “significant technical problems” because it is larger and heavier.
“Fortunately, for the W87-1, conditions allow trade space in terms of mass and volume for an IHE-based primary [fission explosive],” the report adds.
It’s unclear how the Nuclear Weapons Council’s directive to end the interoperable warhead effort in its earlier form will affect the Air Force’s fledgling acquisition program for a new GBSD re-entry vehicle, the Mark 21A, which was supposed to carry the IW-1.
The IW-1 initiative aimed to update the Air Force’s W78 and the Navy’s W88 and package them together into a warhead that could be used by either service’s nuclear arsenal. Now, a November 2018 GAO publication says the Navy plans to “complete a study examining the feasibility of using the nuclear explosive package developed for the W78 replacement warhead in its SLBM [Submarine Launched Ballistic Missile] system by the end of fiscal year 2019.”
The Nuclear Weapons Council approved the W87-1 program in August 2018 to start in Fiscal 2019, according to NNSA. W87-1 received $53 million this fiscal year. A chart included in the document, which projects costs through Fiscal 2037, shows annual spending on W87-1 would peak around $700 million in Fiscal 2030 under a low estimate, or at about $1.2 billion in Fiscal 2031 under a high estimate.
“Previous [NNSA Stockpile Stewardship and Management Plan] estimates, which reflect the [Interoperable Warhead 1] program, underestimated the complexity of addressing challenges of newly manufactured warhead components including development of IHE, enhanced classification anticipated with GBSD, surety features in ballistic missiles, new capability needed for secondary and nuclear explosive package work, increased program management control, and integration with [the] GBSD and Air Force aeroshell acquisition program,” the report states. “These complexities have been adjusted based on experiences and lessons learned from the W80-4, B61-12, and W88 Alt 370 programs. This projection more accurately reflects programmatic funding needs than previous estimates for IW-1.”
Kingston Reif, director for disarmament and threat reduction policy at the Arms Control Association, praised the IW-1 plan’s cancellation, calling it unnecessary and almost certainly financially infeasible.
“The lessened commitment to interoperable warheads does not appear to have reduced the projected cost of replacing the W78,” Reif said in a Jan. 30 email. “Indeed, the report notes that previous NNSA estimates underestimated the complexity and cost of the IW-1! Which should cause us to be skeptical about the estimated cost of the W87-1!”
GAO showed NNSA spent $114.5 million on the W78 replacement program—later known as IW-1 before becoming W87-1—between 2011 and 2014. From Fiscal 2015 to 2017, another $4.3 million was carried over from past years to close out life-extension programs for the W78 and W88 warheads.
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