Laboratory B in Sungulʹ (Russian: Лаборатория Б в Сунгуль) is a now-ruined and abandoned building that was one of the laboratories under the 9th Chief Directorate of the NKVD (MVD after 1946) that contributed to the Soviet program of nuclear weapons. It was created in 1946 and closed in 1955, when some of its personnel were merged with the second Soviet nuclear design and assembly facility. It was run as a sharashka – a secret scientific facility run as a prison. Laboratory B employed German scientists from 1947 to 1953. It had two scientific divisions, radiochemistry and ; the latter was headed by the world-renowned geneticist N. V. Timofeev-Resovskij. For two years, the renowned German chemist, Nikolaus Riehl was the scientific director.