Jen DiMascio Washington

In the Energy Department's National Nuclear Security Administration, (NNSA), officials of nuclear weapons programs try to keep them out of the limelight. But extending the life of the B61 is attracting all kinds of unwanted attention.

The cost of the nuclear bomb has doubled, with estimates now projecting that the weapon designed to defend Europe could cost $10 billion. On top of the weapon's ballooning price tag, the Air Force is working on a $1.2 billion tail kit program that adds a limited guidance capability to the bomb. And the arms control community is starting to buzz about the implications.

News about the B61's cost growth and two-year schedule delay is gaining traction on Capitol Hill. The concern among lawmakers could have implications for the program and the NNSA that oversees the U.S. nuclear force.

B61 bombs are the oldest in the U.S. stockpile. They entered the force in the 1970s, and can be used on fighter jets and long-range bombers. The arsenal has five different versions, both strategic and tactical, focused on protecting NATO members.

The latest life-extension program (LEP) aims to extend their life, merging four of those variants, all with different-sized explosive capabilities, into the B61-12. The B61-12 would draw on the design of the smallest nuclear explosive, or yield, weapon. The administration says using one variant will save money, and the B61-12 weapon would add an advanced security system to prevent unauthorized access to the weapons.

A wide range of players within the nuclear weapons complex are involved in the life-extension program. According to a Government Accountability Office report from 2011, Los Alamos National Laboratory in New Mexico and Sandia National Laboratory—run by a subsidiary of Lockheed Martin, in New Mexico and California—are directly involved in designing the refurbished B61. NNSA's Pantex Plant in Texas is tasked with assembling key subcomponents of the refurbished bomb. Additional work is completed at the Kansas City (Mo.) Plant. And a host of contractors, including Lockheed Martin and Boeing, are vying for the right to assemble the tail kit.