Some of the oldest of the weapons in the active stockpile are versions of the B61 bomb, an aircraft-delivered weapon that is a key component of the United States’ commitments to the North Atlantic Treaty Organization’s (NATO) nuclear deterrent. 2The B61s committed to NATO are maintained in an operational configuration and can be delivered by both U.S. fighter aircraft and aircraft of predesignated, trained, and certified NATO allies.
The B61-12 LEP will consolidate and replace the B61-3, -4, -7, and -10 to reduce the number of gravity bombs in the stockpile, consistent with Nuclear Posture Review Report (DOD 2010) objectives. The first production unit is planned for FY 2020. The program is running on schedule and within budget.
The National Nuclear Security Administration announced the successful field test of the modernized gravity nuclear bomb in Nevada. The NNSA and the US Air Force completed the first qualification flight test of the B61-12 gravity nuclear bomb on 14 March 2017 at the Tonopah Test Range in Nevada, the agency announced. The test was intended to evaluate the weapon’s “non-nuclear functions" and the capability of the F-16 fighter to successfully deploy the bomb. An F-16 fighter from Nellis Air Force Base dropped the “non-nuclear test assembly," the NNSA said in a statement. “The successful test provides critical qualification data to validate that the baseline design meets military requirements," said Brigadier General Michael Lutton, NNSA’s principal assistant deputy administrator for military application. The NNSA is part of the Department of Energy, which is charged with managing US nuclear weapons.
To maintain the readiness of the B61 and other weapons in the stockpile, the Department of Energy’s (DOE) National Nuclear Security Administration (NNSA) and DOD undertake life extension programs (LEP) that entail refurbishing or replacing weapons’ components to extend the lives of weapons by 20 years or more.
Under the B61 LEP, NNSA and the Air Force—the armed service responsible for air-delivered weapons such as the B61—plan to consolidate four of the five versions of the B61 bomb (B61 legacy bombs), each of which was designed to fulfill specific military requirements, into a single weapon known as the B61-12, which will be equipped with a new tail kit guidance assembly that will enable it to meet all military requirements.
Legacy B61 bombs comprise three tactical bombs, known as the B61-3, the B61-4, and the B61-10, and two strategic bombs, the B61-7 and the B61-11. The B61-12 LEP consolidates capabilities of the three tactical variants and the B61-7.
The single variant will operate in two modes: System 1 (analog/ballistic mode) and System 2 (digital/guided mode). The B61 Mod 12 Life Extension Program Tailkit Assembly (B61 Mod 12 LEP TKA) (herein referred to as B61-12 TKA) is the enabler for realizing System 2. This is an Air Force led, joint DoD/Department of Energy (DOE) program managed through the B61 LEP Project Officers Group and its subgroups. The consolidation of B61 legacy bombs into the single B61-12 weapon is expected to allow NNSA and DOD to reduce the number of nuclear gravity bombs in the stockpile by about one-half.
In addition, DOD and NNSA expect the B61-12 to provide mission capabilities that will allow the retirement of a megaton-class weapon, the B83-1 bomb, that would be expected to produce significantly more collateral damage than the lower-yield B61-12. Altogether, the reduction in the number of bombs and retirement of the B83-1 bomb will reduce the amount of special nuclear material in the US stockpile of gravity bombs by more than one-half.
The B61-12 will be able to strike within 30 meters of its target, while existing US nuclear bombs have circular error probabilities (CEP) of between 110-170 meters. The B61-12 accuracy allows the bomb to destroy targets that would have previously necessitated the use of a larger but more indiscriminate weapon [hence the retirement of the megaton-class B83-1 bomb]. Given the B61-12 relatively low yield, it would produce less nuclear fallout than earlier nuclear weapons. Critics charge that this lower fallout also lowers the cost and scope of a nuclear strike — which could in turn increase the possibility that the bomb would actually be used in a military engagement.
Because critical components in B61 legacy bombs are approaching the end of their operational lives, NNSA and DOD have underscored the importance of beginning production of the B61-12 in 2020 and completing the LEP by 2024 to uphold the United States’ commitments to NATO’s nuclear deterrent. With thousands of individual components, the B61-12 LEP is the most complicated and expensive LEP undertaken since DOE initiated stockpile life extension activities in January 1996.
The B61-12 life extension program's (LEP) managers have developed a management approach that officials from the Department of Energy's (DOE) National Nuclear Security Administration (NNSA) and the Department of Defense (DOD) regard as improved over the management approach used for past LEPs, which experienced schedule delays and cost overruns.
Among other things, the B61-12 LEP is the first LEP to use earned value management, a tool that measures the planned versus actual value of work accomplished in a given period, which may help NNSA ensure that work progresses on budget and on schedule. It is also the first LEP to integrate the schedules and cost estimates for activities at all participating NNSA sites. NNSA used this new approach to inform its first Program Execution Guide for defense programs, issued in August 2014, which applies to all NNSA defense programs. NNSA's new management approach notwithstanding, the B61-12 LEP faces ongoing management challenges in some areas, including staff shortfalls and an earned value management system that has yet to be tested. The new management approach may help the LEP address these potential challenges, but it is too soon to determine whether this will be the case.
To manage risks in the B61-12 LEP, NNSA and the Air Force use a risk management database and integrated schedules to categorize risks and incorporate risk management steps in the schedules. According to NNSA and Air Force officials, some risks have already been managed in this manner. For example, NNSA estimates that making a needed material procurement in advance prevented a potential delay of more than a year and a potential cost increase of more than $2 million. Remaining risks include the risk that components may fail in certain flight environments and risks related to testing of certain nonnuclear components. NNSA is also working to ensure future compatibility with the F-35 aircraft.
NNSA and Air Force officials said they will not know for several years whether steps planned to manage these risks are adequate. A constrained development and production schedule—which DOE's and DOD's Nuclear Weapons Council characterized as having “little, if any, margin left"—complicates efforts to manage risks. Factors constraining the schedule include the aging of components in current versions of the B61, delays in starting the B61-12 LEP because of a lengthy design study, the effects of sequestration, and the need to complete the B61-12 LEP so that NNSA can begin other planned LEPs.
In February 2012, the Nuclear Weapons Council, chaired by the Under Secretary of Defense for Acquisition, Technology and Logistics (USD(AT&L)), authorized the B61 Life Extension Program to progress to Phase 6.3 of the nuclear systems life cycle as defined by DoD Instruction 5030.55. This major milestone cleared the path for the National Nuclear Security Administration to begin Engineering Development for the B61-12 warhead refurbishment effort.
On November 27, 2012, the B61-12 TKA program office awarded a Cost Plus Incentive Fee contract to Boeing for EMD Phase 1 with priced options for EMD Phase 2 and a Technical Data Package. In addition, the contract contains production lot design-to-unit-cost goals, which are tied to performance incentives for the production phase of the program. Finally, the APB was approved on December 14, 2012. Major risks include concurrent development activities being conducted by the DoD for the B61-12 TKA and the Department of Energy for the Bomb Assembly. Therefore, threshold dates are one year beyond objective dates in the APB for Milestone C, First TKA Production Delivery, and Full Rate Production Decision to mitigate the risks associated with concurrent development activities.
In April 2013, the B61-12 TKA program office completed a System Requirements Review followed by a System Functional Review in May 2013. In August 2013, the B61-12 TKA program office, in conjunction with Boeing, completed the EMD Phase 1 Integrated Baseline Review.
The United States Air Force (USAF) and National Nuclear Security Administration (NNSA) completed the first development flight test of a non-nuclear B61-12 gravity bomb at Tonopah Test Range in Nevada on 01 July 2015. This test marks a major milestone for the B61-12 Life Extension Program, demonstrating end-to-end system performance under representative delivery conditions.
The flight test asset consisted of hardware designed by Sandia National and Los Alamos National Laboratories, manufactured by the National Security Enterprise Plants, and mated to the USAF tail-kit assembly, designed by The Boeing Company. This test was the first of three development flight tests for the B61-12 Life Extension Program (LEP), with two additional development flight tests scheduled for later this calendar year. This test demonstrated successful performance in realistic flight environments followed by an effective release of a development test unit from a USAF F-15E from Nellis AFB. Telemetry, tracking and video data were successfully collected. This test provided confidence in the weapon system and instrumentation system designs and the hardware at its current state prior to going to a baseline design review in 2016.
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