The U282 is a television efficiency diode, used to return energy from the collapsing field in the line coils to the HT rail.
The peak current is given as 600 mA.
Mazda had great difficulty producing rectifier valves around the early 1950s. They all had flaking cathodes and usually ended in a firework display.
The construction is of two rectifier stacks connected internally in parallel.
The wide glass tube envelope is 29 mm in diameter, and excluding the base pins is 85 mm tall.
References: habits article & 1040
Absolute Maximum Operating Conditions¶
Updated January 18, 2017.