At our Round there is the Rule of gaining the righteous Fury on Psychic attacks. To confirm the righteous Fury the Psyker has to make a challenging (+0) Willpower-Roll. If the Roll was successfull the same rules apply as a normal Weapon.
Additionaly the Psyker who wants to cast Holocaust has to be afraid that the Fire burns so hat that he will burn his own Soul away. Because the Righteous Fury is on EACH Damage Roll with a natural 0.