I have a vague recollection of K.A. Applegate's Remnants series briefly describing the failure of the protective systems, I want to say in the second book. It was one of those rushed, fleeing a dying Earth scenarios, and the majority of the crew died in cryosleep before arriving. There was some stuff about the effect it had on the corpses, which got a little gruesome.
From an actual science perspective, even an inch of lead will work fantastically, but water is now and will always be my preferred solution to a too-many-zoomies problem. (See Chernobyl's graphite sheathes for reasons why solids can really screw you over.) The thing is that lead is a) heavy and b) itself toxic. You don't want your spaceship any heavier than it has to be if you have to get it off the ground and you don't want to fill it with something that you know is toxic without a really good reason and a modicum of assurance that it won't get into the food. You could thwart the heaviness if you build the ship in space and never have to break atmosphere, but the toxicity would require engineering an internal jacket to protect your crew from their protection.
And since NASA can't decide whether there is a small problem, a big problem, or no problem, you can do that part as big as you want. (Radiation studies are hideously complicated, and the sample sizes they are working with for their studies are, by necessity, too small to be accurately extrapolated onto the populace at large. Mostly what they are sure about is that the low-energy types of radiation in cosmic radiation (maybe) doesn't cause cancer, which (mostly) conflicts with what we already knew from bad decisions made in the middle part of the last century. Radiation is wild, y'all.)
You should note that the most extreme estimates have an annual dose of ~1Sv for (Unshielded) spaceflight, and that in 2000 the occupational limits dropped from 4Sv to 2Sv, lifetime. There is some talk that there is a greater threat to women, because of breast cancer and ovarian cancer, but there is exactly 0 scientific data to support that. Actually, there is 0 scientific research done on it, it's total speculation. Rough estimates and incomplete data suggest liver tumors (Of all things) are the most likely type.
I'm pretty sure this does not answer your initial question. Sorry.
