Question: Julin Bristol is the codename given to a nuclear weapon test conducted at the Nevada Test Site on 26 November 1991, as part of which United States's  nuclear test series was a group of 7 nuclear tests conducted in 1991–1992, the final series of US nuclear tests, it was the last test explosion of a British nuclear weapon?

Context paragraphs:
Operation Julin: The United States's Julin nuclear test series was a group of 7 nuclear tests conducted in 1991–1992.  These tests followed the "Operation Sculpin" series, and were the last before negotiations began for the Comprehensive Test Ban Treaty.

1989 Soviet nuclear tests: The Soviet Union's 1989 nuclear test series was a group of 7 nuclear tests conducted in 1989.  These tests followed the "1988 Soviet nuclear tests" series and preceded the "1990 Soviet nuclear tests" series.

1985 Soviet nuclear tests: The Soviet Union's 1985 nuclear test series was a group of 10 nuclear tests conducted in 1985.  These tests followed the "1984 Soviet nuclear tests" series and preceded the "1987 Soviet nuclear tests" series.

1989–91 French nuclear tests: The France's 1989-1991 nuclear test series was a group of 21 nuclear tests conducted in 1989-1991.  These tests followed the "1986–88 French nuclear tests" series and preceded the "1995–96 French nuclear tests" series.

1966–70 French nuclear tests: The France's 1966–1970 nuclear test series was a group of 22 nuclear tests conducted in 1966–1970.  These tests followed the "In Ekker series, French nuclear tests" series and preceded the "1971–74 French nuclear tests" series.

1955 Soviet nuclear tests: The Soviet Union's 1955 nuclear test series was a group of 7 nuclear tests conducted in 1955.  These tests followed the "1954 Soviet nuclear tests" series and preceded the "1956 Soviet nuclear tests" series.

1987 Soviet nuclear tests: The Soviet Union's 1987 nuclear test series was a group of 24 nuclear tests conducted in 1987.  These tests followed the "1985 Soviet nuclear tests" series and preceded the "1988 Soviet nuclear tests" series.

Julin Bristol: Julin Bristol is the codename given to a nuclear weapon test conducted at the Nevada Test Site on 26 November 1991.  Conducted as part of Operation Julin, the final series of US nuclear tests, it was the last test explosion of a British nuclear weapon.  Both the US and UK, as signatories of the Comprehensive Nuclear-Test-Ban Treaty, ceased nuclear testing after Operation Julin.

In Ekker series, French nuclear tests: The France's In Ekker nuclear test series was a group of 14 nuclear tests conducted in 1961-1966.  These tests followed the "Reggane series, French nuclear tests" series and preceded the "1966–70 French nuclear tests" series.

1988 Soviet nuclear tests: The Soviet Union's 1988 nuclear test series was a group of 16 nuclear tests conducted in 1988.  These tests followed the "1987 Soviet nuclear tests" series and preceded the "1989 Soviet nuclear tests" series.

Supporting paragraphs: Julin Bristol Operation Julin
Answer: Operation Julin