Yellow Sun nuclear weapon
Yellow Sun was the first thermonuclear weapon developed for operational service in the UK. Yellow Sun was a fission/fusion device intended for airdrop. The name referred to the bomb's casing, while the physics package wasGreen Grass. The neutron source for the physics package was called Blue Stone.
The initial Yellow Sun Stage 1 used the Green Bamboo tamper boosted fission warhead while Yellow Sun Stage 2 used a Green Granite fusion warhead with a yield of 400Kt.
Yellow Sun Mk1 was essentially a boosted fission weapon with a yield of about 500KT. Any weapon with a yield in excess of 500Kt was referred to as a Megaton weapon. Yellow Sun was also known as "Bomb, HE, 7000lb, HC"
Yellow Sun Mk2 had a yield of 1Mt. Yellow Sun was withdrawn when the RAF relinquished the strategic nuclear deterrent to the Royal Navy Polaris submarines.
The photograph is Crown Copyright.
Nuclear Weapons or The Colour Codes