The Knolls Atomic Power Laboratory (KAPL)-Kesselring, is engaged solely in research and development for the design and operation of naval nuclear propulsion plants. The Kesselring Site Operation (KSO) is located about 5 miles from Ballston Spa, NY, and 8 miles from the resort area of Saratoga Springs, NY.

By 1955 KAPL had designed a reactor that could propel a submarine for about three years of normal operations. A prototype of that first KAPL reactor was built and operated at the laboratory's Kesselring Site in West Milton, New York. The first shipboard application of the design was in the submarine SEAWOLF (SSN 575), which was commissioned in 1957.

Between 1958 and 1992 KSO contained four high power Naval Prototype reactor plants, namely the S3G, D1G, S7G, and S8G. These prototypes are essentially a section of the ship containing the power plant, or the reactor compartment and the engine room. The two oldest, S3G and D1G, have since been decommisioned.

Current activities include operation of the S7G Modifications and Additions to Reactor Facilities [MARF] Nuclear Prototype Training Unit in Ballston Spa. KAPL continues to train Navy nuclear propulsion plant operators at its prototype site in West Milton. KAPL has trained over 49,000 officers and enlisted personnel for the U.S. Navy since the beginning of the laboratory. Electric Boat Corp. is one of the contractors at the Kenneth A. Kesselring site in West Milton. The company refurbished the MARF and S8G nuclear reactors, with the project being completed in late 1997.

Activities relating to naval nuclear propulsion systems are performed in accordance with the requirements and authority of the Naval Nuclear Propulsion Program, a joint DOE and U.S. Department of Navy program responsible for all activities relating to naval nuclear propulsion. The Kesselring prototype site is also used to provide full-scale testing of propulsion plant hardware and to train personnel to operate these plants.