Operation Fusileer

Operation Fusileer. This was a series of underground nuclear tests conducted by the United States at the Nevada Test Site between 1985 and 1986. The operation was managed by scientists from the Lawrence Livermore National Laboratory under the auspices of the United States Department of Energy. Its primary focus was on advancing the understanding of nuclear weapon physics, particularly related to thermonuclear secondary stages and the effects of radiation on various materials.

Background and objectives

The program emerged during the latter stages of the Cold War, a period characterized by intense technological competition between the United States and the Soviet Union. Following the ratification of treaties like the Threshold Test Ban Treaty, the United States shifted its testing focus entirely underground. The strategic objectives of Operation Fusileer were multifaceted, aiming to validate new computer models for nuclear weapon design and gather crucial data on nuclear fusion reactions. These tests were part of a broader effort to ensure the reliability and safety of the enduring United States nuclear arsenal without conducting full-scale atmospheric detonations. Key figures in the Strategic Defense Initiative and agencies like the Defense Nuclear Agency had a vested interest in the results, which pertained to understanding X-ray output and radiation flow in weapon systems.

Planning and preparation

Extensive planning for the operation was led by physicists and engineers at the Lawrence Livermore National Laboratory, a key facility in the nation's nuclear weapons complex. Preparations involved sophisticated diagnostic equipment and required precise coordination with personnel from the Nevada Test Site and the United States Department of Energy. The experiments were designed to be contained within deep vertical shafts drilled into the desert geology of Yucca Flat or Pahute Mesa. Teams from the Sandia National Laboratories often contributed to the design of diagnostic canisters and data acquisition systems. This phase also involved rigorous safety reviews to prevent any release of radioactive material into the environment, adhering to protocols established after earlier incidents like the Baneberry test.

Execution and timeline

The operation comprised multiple individual detonations, each designated with a unique codename. The first test in the series, Fusileer-Azalea, was conducted on December 13, 1985. Subsequent shots, including Fusileer-Diana and Fusileer-Diana Moon, followed in 1986. Each event involved lowering a nuclear device and an array of diagnostic instruments into a prepared shaft, which was then stemmed and sealed. Upon detonation, the immense heat and pressure vaporized surrounding rock, creating a subterranean cavity. Sensitive instruments measured phenomena such as neutron flux, gamma ray spectra, and yield characteristics. Data was transmitted via hardened cables to recording stations before the shockwave destroyed the immediate experimental setup.

Results and impact

The tests successfully provided a wealth of data on secondary stage performance and radiation hydrodynamics, directly informing the ongoing Stockpile stewardship program. Scientists confirmed predictions about weapon physics and gained new insights into materials behavior under extreme conditions. The results had significant implications for the modernization efforts of systems like the B83 nuclear bomb and contributed to the knowledge base for potential future designs. Furthermore, the data aided in the calibration of supercomputers at facilities like the Los Alamos National Laboratory, enhancing the capability for computer simulation of nuclear explosions, which became paramount following the signing of the Comprehensive Nuclear-Test-Ban Treaty.

Aftermath and legacy

Operation Fusileer represented one of the final chapters of full-scale underground nuclear testing by the United States before the moratorium that began in 1992. The technical legacy of its findings was integrated into the Science Based Stockpile Stewardship program, established to maintain confidence in the nuclear deterrent without live testing. The site of the tests, the Nevada Test Site, was later renamed the Nevada National Security Site as its mission evolved toward subcritical experiments and non-proliferation work. The data archives from operations like Fusileer remain vital for informing the work of the National Nuclear Security Administration and for training new generations of weapons scientists in an era of no-yield testing.

Category:Cold War nuclear weapons testing of the United States Category:1985 in the United States Category:1986 in the United States Category:Nevada Test Site