The Russians don't seem to mind equipping Iran with the equipment and materials to go nuclear. Maybe this is why:
TSAR Hydrogen Bomb Detonated by USSR
The TSAR was "capable" of 100 megatons, but the video shows one throttled back to just 50...
The original, November 1961 A.E.C. estimate of the yield was 55–60 Mt, but since 1991 all Russian sources have stated its yield as 50 Mt. Khrushchev warned in a filmed speech to the Supreme Soviet of the existence of a 100 Mt bomb (technically the design was capable of this yield). Although simplistic fireball calculations predicted the fireball would impact the ground, the bomb's own shock wave reflected back and prevented this.[9] The fireball reached nearly as high as the altitude of the release plane and was visible at almost 1,000 kilometres (620 mi) away from where it ascended. The subsequent mushroom cloud was about 64 kilometres (40 mi) high (over seven times the height of Mount Everest), which meant that the cloud was above the stratosphere and well inside the mesosphere when it peaked. The base of the cloud was 40 kilometres (25 mi) wide. All buildings in the village of Severny (both wooden and brick), located 55 kilometres (34 mi) from ground zero within the Sukhoy Nos test range, were destroyed. In districts hundreds of kilometers from ground zero wooden houses were destroyed, stone ones lost their roofs, windows and doors; and radio communications were interrupted for almost one hour. One participant in the test saw a bright flash through dark goggles and felt the effects of a thermal pulse even at a distance of 270 kilometres (170 mi). The heat from the explosion could have caused third-degree burns 100 km (62 mi) away from ground zero. A shock wave was observed in the air at Dikson settlement 700 kilometres (430 mi) away; windowpanes were partially broken to distances of 900 kilometres (560 mi).[10] Atmospheric focusing caused blast damage at even greater distances, breaking windows in Norway and Finland. The seismic shock[verification needed] created by the detonation was measurable even on its third passage around the Earth.[11] Its seismic body wave magnitude was about 5 to 5.25.[9] The energy yield was around 8.1 on the Richter scale but, since the bomb was detonated in air rather than underground, most of the energy was not converted to seismic waves. The TNT equivalent of the 50 Mt test could be represented by a cube of TNT 312 metres (1023 feet) on a side, approximately the height of the Eiffel Tower.