Editing Nuclear weapon design (section)

===Pure fusion weapons===
{{Main|Pure fusion weapon}}

Since the 1950s, the United States and Soviet Union investigated the possibility of releasing significant amounts of nuclear fusion energy without the use of a fission primary. Such "pure fusion weapons" were primarily imagined as low-yield, tactical nuclear weapons whose advantage would be their ability to be used without producing fallout on the scale of weapons that release fission products. In 1998, the [[United States Department of Energy]] declassified the following:
{{blockquote|
(1) Fact that the DOE made a substantial investment in the past to develop a pure fusion weapon

(2)	That the U.S. does not have and is not developing a pure fusion weapon; and
(3)	That no credible design for a pure fusion weapon resulted from the DOE investment.<ref>{{cite web|title=Restricted Data Declassification Decisions, 1946 to the Present (RDD-7)|url=https://sgp.fas.org/othergov/doe/rdd-7.html|date=1 January 2001}}</ref>}}

[[Red mercury]], a likely hoax substance, has been hyped as a catalyst for a pure fusion weapon.{{Citation needed|date=April 2024}}