We claim the ornamental design for radiation protective headwear, as shown and described.
FIG. 1 is a front view of a radiation protective headwear in a state of use in which it is worn on a user's head;
FIG. 2 is a top view of the radiation protective headwear in a state of use in which it is worn on a user's head;
FIG. 3 is a left side view of the radiation protective headwear in a state of use in which it is worn on a user's head;
FIG. 4 is a right side elevation view of the radiation protective headwear in a state of use in which it is worn on a user's head;
FIG. 5 is a rear view of the radiation protective headwear in a state of use in which it is worn on a user's head; and,
FIG. 6 is a right side view of the radiation protective headwear in a state of non-use in which it is collapsed, a left side view being a mirror image thereof.
The broken lines illustrate environment which forms no part of what is claimed.