It's probably related to ITU-R BT.601
to get the R,G,B levels.
As for what the phosphor wavelengths are, I'd guess that they are similar to CRT phosphors, as here: http://en.wikipedia.org/wiki/Phosphor#Cathode_ray_tubes
Red: Yttrium oxide-sulfide activated with europium is used as the red phosphor in color CRTs. The development of color TVs took a long time due to the long search for a red phosphor. The first red emitting rare earth phosphor, YVO4,Eu3, was introduced by Levine and Palilla as a primary color in television in 1964. In single crystal form, it was used as an excellent polarizer and laser material.
Green: Combination of zinc sulfide with copper, the P31 phosphor or ZnS:Cu, provides green light peaking at 531 nm, with long glow.
Blue: Combination of zinc sulfide with few ppm of silver, the ZnS:Ag, when excited by electrons, provides strong blue glow with maximum at 450 nm, with short afterglow with 200 nanosecond duration. It is known as the P22B phosphor. This material, zinc sulfide silver, is still one of the most efficient phosphors in cathode ray tubes. It is used as a blue phosphor in color CRTs.
Not sure what red phosphor wavelength is, but some research on the subject may reveal it.
I'd guess modern plasmas vary the phosphors slightly for improved efficiency and reduced afterglow.
If you have well defined phosphors then all you need to get right is the YCbCr to RGB.