Editing Red Snow (section)

==Design==
Red Snow used the [[Thermonuclear weapon#Basic principle|primary stage]] Peter, an anglicised version of the US Python device used in the W28.<ref name=NukeInfoWE177>{{cite web |url=http://www.nuclear-weapons.info/vw.htm#WE.177 |title=WE.177 |last=Burnell |first=Brian |date=2018-04-15 |website=Nuclear Weapons: a Guide to British Nuclear Weapon Projects |access-date=2022-05-03 |quote="PETER – A boosted fission device, an anglicised copy of the W-34 Python primary used in the Red Snow strategic warhead and it was already in production in the UK, so could be available quickly. Yield of 11 kt was not capable of enlargement to the sizes specified by OR.1176 / 1177." |archive-date=27 September 2018 |archive-url=https://web.archive.org/web/20180927142646/http://www.nuclear-weapons.info/vw.htm#WE.177 |url-status=live }}</ref> The Peter device contained {{convert|2.25|kg|lb}} of plutonium and {{convert|1.4|kg|lb}} of uranium. The kiloton Red Snow contained {{convert|1.6|kg|lb}} of plutonium, {{convert|11|kg|lb}} of uranium, {{convert|0.6|kg|lb}} of lithium deuteride and {{convert|2.49|to|2.54|g}} of tritium, while in megaton Red Snow all the values stayed the same except the lithium deuteride amount which increased to {{convert|16|kg|lb}}.<ref name=UKAEA/>

The device was fitted inside weapon cases from the older Yellow Sun weapons. This may have been to simplify crew retraining, simplify integration of the new weapon to existing platforms, or to hide the radical reduction in weapon size.<ref name=NukeArcUK/>